Sample records for conditional forebrain inactivation
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Tabuchi, Katsuhiko; Chen, Guiquan; Südhof, Thomas C; Shen, Jie
2009-06-03
Loss of presenilin function in adult mouse brains causes memory loss and age-related neurodegeneration. Since presenilin possesses gamma-secretase-dependent and -independent activities, it remains unknown which activity is required for presenilin-dependent memory formation and neuronal survival. To address this question, we generated postnatal forebrain-specific nicastrin conditional knock-out (cKO) mice, in which nicastrin, a subunit of gamma-secretase, is inactivated selectively in mature excitatory neurons of the cerebral cortex. nicastrin cKO mice display progressive impairment in learning and memory and exhibit age-dependent cortical neuronal loss, accompanied by astrocytosis, microgliosis, and hyperphosphorylation of the microtubule-associated protein Tau. The neurodegeneration observed in nicastrin cKO mice likely occurs via apoptosis, as evidenced by increased numbers of apoptotic neurons. These findings demonstrate an essential role of nicastrin in the execution of learning and memory and the maintenance of neuronal survival in the brain and suggest that presenilin functions in memory and neuronal survival via its role as a gamma-secretase subunit.
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Developmentally defined forebrain circuits regulate appetitive and aversive olfactory learning.
Muthusamy, Nagendran; Zhang, Xuying; Johnson, Caroline A; Yadav, Prem N; Ghashghaei, H Troy
2017-01-01
Postnatal and adult neurogenesis are region- and modality-specific, but the significance of developmentally distinct neuronal populations remains unclear. We demonstrate that chemogenetic inactivation of a subset of forebrain and olfactory neurons generated at birth disrupts responses to an aversive odor. In contrast, novel appetitive odor learning is sensitive to inactivation of adult-born neurons, revealing that developmentally defined sets of neurons may differentially participate in hedonic aspects of sensory learning.
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Forebrain pathway for auditory space processing in the barn owl.
Cohen, Y E; Miller, G L; Knudsen, E I
1998-02-01
The forebrain plays an important role in many aspects of sound localization behavior. Yet, the forebrain pathway that processes auditory spatial information is not known for any species. Using standard anatomic labeling techniques, we used a "top-down" approach to trace the flow of auditory spatial information from an output area of the forebrain sound localization pathway (the auditory archistriatum, AAr), back through the forebrain, and into the auditory midbrain. Previous work has demonstrated that AAr units are specialized for auditory space processing. The results presented here show that the AAr receives afferent input from Field L both directly and indirectly via the caudolateral neostriatum. Afferent input to Field L originates mainly in the auditory thalamus, nucleus ovoidalis, which, in turn, receives input from the central nucleus of the inferior colliculus. In addition, we confirmed previously reported projections of the AAr to the basal ganglia, the external nucleus of the inferior colliculus (ICX), the deep layers of the optic tectum, and various brain stem nuclei. A series of inactivation experiments demonstrated that the sharp tuning of AAr sites for binaural spatial cues depends on Field L input but not on input from the auditory space map in the midbrain ICX: pharmacological inactivation of Field L eliminated completely auditory responses in the AAr, whereas bilateral ablation of the midbrain ICX had no appreciable effect on AAr responses. We conclude, therefore, that the forebrain sound localization pathway can process auditory spatial information independently of the midbrain localization pathway.
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Wei, Catherine J.; Singer, Philipp; Coelho, Joana; Boison, Detlev; Feldon, Joram; Yee, Benjamin K.; Chen, Jiang-Fan
2011-01-01
The adenosine A2A receptor (A2AR) is highly enriched in the striatum where it is uniquely positioned to integrate dopaminergic, glutamatergic, and other signals to modulate cognition. Although previous studies support the hypothesis that A2AR inactivation can be pro-cognitive, analyses of A2AR's effects on cognitive functions have been restricted to a small subset of cognitive domains. Furthermore, the relative contribution of A2ARs in distinct brain regions remains largely unknown. Here, we studied the regulation of multiple memory processes by brain region-specific populations of A2ARs. Specifically, we evaluated the cognitive impacts of conditional A2AR deletion restricted to either the entire forebrain (i.e., cerebral cortex, hippocampus, and striatum, fb-A2AR KO) or to striatum alone (st-A2AR KO) in recognition memory, working memory, reference memory, and reversal learning. This comprehensive, comparative analysis showed for the first time that depletion of A2AR-dependent signaling in either the entire forebrain or striatum alone is associated with two specific phenotypes indicative of cognitive flexibility—enhanced working memory and enhanced reversal learning. These selective pro-cognitive phenotypes seemed largely attributed to inactivation of striatal A2ARs as they were captured by A2AR deletion restricted to striatal neurons. Neither spatial reference memory acquisition nor spatial recognition memory were grossly affected, and no evidence for compensatory changes in striatal or cortical D1, D2, or A1 receptor expression was found. This study provides the first direct demonstration that targeting striatal A2ARs may be an effective, novel strategy to facilitate cognitive flexibility under normal and pathologic conditions. PMID:21693634
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Wei, Catherine J; Singer, Philipp; Coelho, Joana; Boison, Detlev; Feldon, Joram; Yee, Benjamin K; Chen, Jiang-Fan
2011-01-01
The adenosine A(2A) receptor (A(2A)R) is highly enriched in the striatum where it is uniquely positioned to integrate dopaminergic, glutamatergic, and other signals to modulate cognition. Although previous studies support the hypothesis that A(2A)R inactivation can be pro-cognitive, analyses of A(2A)R's effects on cognitive functions have been restricted to a small subset of cognitive domains. Furthermore, the relative contribution of A(2A)Rs in distinct brain regions remains largely unknown. Here, we studied the regulation of multiple memory processes by brain region-specific populations of A(2A)Rs. Specifically, we evaluated the cognitive impacts of conditional A(2A)R deletion restricted to either the entire forebrain (i.e., cerebral cortex, hippocampus, and striatum, fb-A(2A)R KO) or to striatum alone (st-A(2A)R KO) in recognition memory, working memory, reference memory, and reversal learning. This comprehensive, comparative analysis showed for the first time that depletion of A(2A)R-dependent signaling in either the entire forebrain or striatum alone is associated with two specific phenotypes indicative of cognitive flexibility-enhanced working memory and enhanced reversal learning. These selective pro-cognitive phenotypes seemed largely attributed to inactivation of striatal A(2A)Rs as they were captured by A(2A)R deletion restricted to striatal neurons. Neither spatial reference memory acquisition nor spatial recognition memory were grossly affected, and no evidence for compensatory changes in striatal or cortical D(1), D(2), or A(1) receptor expression was found. This study provides the first direct demonstration that targeting striatal A(2A)Rs may be an effective, novel strategy to facilitate cognitive flexibility under normal and pathologic conditions.
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Wang, Xiao-Dong; Chen, Yuncai; Wolf, Miriam; Wagner, Klaus V.; Liebl, Claudia; Scharf, Sebastian H.; Harbich, Daniela; Mayer, Bianca; Wurst, Wolfgang; Holsboer, Florian; Deussing, Jan M.; Baram, Tallie Z.; Müller, Marianne B.; Schmidt, Mathias V.
2011-01-01
Chronic stress evokes profound structural and molecular changes in the hippocampus, which may underlie spatial memory deficits. Corticotropin-releasing hormone (CRH) and CRH receptor 1 (CRHR1) mediate some of the rapid effects of stress on dendritic spine morphology and modulate learning and memory, thus providing a potential molecular basis for impaired synaptic plasticity and spatial memory by repeated stress exposure. Using adult male mice with CRHR1 conditionally inactivated in the forebrain regions, we investigated the role of CRH-CRHR1 signaling in the effects of chronic social defeat stress on spatial memory, the dendritic morphology of hippocampal CA3 pyramidal neurons, and the hippocampal expression of nectin-3, a synaptic cell adhesion molecule important in synaptic remodeling. In chronically stressed wild-type mice, spatial memory was disrupted, and the complexity of apical dendrites of CA3 neurons reduced. In contrast, stressed mice with forebrain CRHR1 deficiency exhibited normal dendritic morphology of CA3 neurons and mild impairments in spatial memory. Additionally, we showed that the expression of nectin-3 in the CA3 area was regulated by chronic stress in a CRHR1-dependent fashion and associated with spatial memory and dendritic complexity. Moreover, forebrain CRHR1 deficiency prevented the down-regulation of hippocampal glucocorticoid receptor expression by chronic stress but induced increased body weight gain during persistent stress exposure. These findings underscore the important role of forebrain CRH-CRHR1 signaling in modulating chronic stress-induced cognitive, structural and molecular adaptations, with implications for stress-related psychiatric disorders. PMID:21296667
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Ho, Chao-Yi; Berridge, Kent C.
2014-01-01
Disgust is a prototypical type of negative affect. In animal models of excessive disgust, only a few brain sites are known in which localized dysfunction (lesions or neural inactivations) can induce intense ‘disgust reactions’ (e.g., gapes) to a normally pleasant sensation such as sweetness. Here we aimed to map forebrain candidates more precisely to identify where either local neuronal damage (excitotoxin lesions) or local pharmacological inactivation (muscimol-baclofen microinjections) caused rats to emit excessive sensory disgust reactions to sucrose. Our study compared subregions of nucleus accumbens shell, ventral pallidum, lateral hypothalamus and adjacent extended amygdala. Results indicated the posterior half of ventral pallidum to be the only forebrain site where intense sensory disgust gapes to sucrose were induced by both lesions and temporary inactivations (this site was previously identified as a hedonic hotspot for enhancements of sweetness ‘liking’). By comparison, for the nucleus accumbens, temporary GABA inactivations in the caudal half of the medial shell also generated sensory disgust but lesions never did at any site. Further, even inactivations failed to induce disgust in the rostral half of accumbens shell (which also contains a hedonic hotspot). In other structures, neither lesions nor inactivations induced disgust as long as the posterior ventral pallidum remained spared. We conclude that the posterior ventral pallidum is an especially crucial hotspot for producing excessive sensory disgust by local pharmacological/lesion dysfunction. By comparison, the nucleus accumbens appears to segregate sites for pharmacological disgust induction and hedonic enhancement into separate posterior versus rostral halves of medial shell. PMID:25229197
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Ho, Chao-Yi; Berridge, Kent C
2014-11-01
Disgust is a prototypical type of negative affect. In animal models of excessive disgust, only a few brain sites are known in which localized dysfunction (lesions or neural inactivations) can induce intense 'disgust reactions' (e.g. gapes) to a normally pleasant sensation such as sweetness. Here, we aimed to map forebrain candidates more precisely, to identify where either local neuronal damage (excitotoxin lesions) or local pharmacological inactivation (muscimol/baclofen microinjections) caused rats to show excessive sensory disgust reactions to sucrose. Our study compared subregions of the nucleus accumbens shell, ventral pallidum, lateral hypothalamus, and adjacent extended amygdala. The results indicated that the posterior half of the ventral pallidum was the only forebrain site where intense sensory disgust gapes in response to sucrose were induced by both lesions and temporary inactivations (this site was previously identified as a hedonic hotspot for enhancements of sweetness 'liking'). By comparison, for the nucleus accumbens, temporary GABA inactivations in the caudal half of the medial shell also generated sensory disgust, but lesions never did at any site. Furthermore, even inactivations failed to induce disgust in the rostral half of the accumbens shell (which also contains a hedonic hotspot). In other structures, neither lesions nor inactivations induced disgust as long as the posterior ventral pallidum remained spared. We conclude that the posterior ventral pallidum is an especially crucial hotspot for producing excessive sensory disgust by local pharmacological/lesion dysfunction. By comparison, the nucleus accumbens appears to segregate sites for pharmacological disgust induction and hedonic enhancement into separate posterior and rostral halves of the medial shell. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.
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Basal Forebrain Gating by Somatostatin Neurons Drives Prefrontal Cortical Activity.
Espinosa, Nelson; Alonso, Alejandra; Morales, Cristian; Espinosa, Pedro; Chávez, Andrés E; Fuentealba, Pablo
2017-11-17
The basal forebrain provides modulatory input to the cortex regulating brain states and cognitive processing. Somatostatin-expressing neurons constitute a heterogeneous GABAergic population known to functionally inhibit basal forebrain cortically projecting cells thus favoring sleep and cortical synchronization. However, it remains unclear if somatostatin cells can regulate population activity patterns in the basal forebrain and modulate cortical dynamics. Here, we demonstrate that somatostatin neurons regulate the corticopetal synaptic output of the basal forebrain impinging on cortical activity and behavior. Optogenetic inactivation of somatostatin neurons in vivo rapidly modified neural activity in the basal forebrain, with the consequent enhancement and desynchronization of activity in the prefrontal cortex, reflected in both neuronal spiking and network oscillations. Cortical activation was partially dependent on cholinergic transmission, suppressing slow waves and potentiating gamma oscillations. In addition, recruitment dynamics was cell type-specific, with interneurons showing similar temporal profiles, but stronger responses than pyramidal cells. Finally, optogenetic stimulation of quiescent animals during resting periods prompted locomotor activity, suggesting generalized cortical activation and increased arousal. Altogether, we provide physiological and behavioral evidence indicating that somatostatin neurons are pivotal in gating the synaptic output of the basal forebrain, thus indirectly controlling cortical operations via both cholinergic and non-cholinergic mechanisms. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Ferguson, Carolyn; Hardy, Steven L; Werner, David F; Hileman, Stanley M; DeLorey, Timothy M; Homanics, Gregg E
2007-01-01
Background The β3 subunit of the γ-aminobutyric acid type A receptor (GABAA-R) has been reported to be important for palate formation, anesthetic action, and normal nervous system function. This subunit has also been implicated in the pathogenesis of Angelman syndrome and autism spectrum disorder. To further investigate involvement of this subunit, we previously produced mice with a global knockout of β3. However, developmental abnormalities, compensation, reduced viability, and numerous behavioral abnormalities limited the usefulness of that murine model. To overcome many of these limitations, a mouse line with a conditionally inactivated β3 gene was engineered. Results Gene targeting and embryonic stem cell technologies were used to create mice in which exon 3 of the β3 subunit was flanked by loxP sites (i.e., floxed). Crossing the floxed β3 mice to a cre general deleter mouse line reproduced the phenotype of the previously described global knockout. Pan-neuronal knockout of β3 was achieved by crossing floxed β3 mice to Synapsin I-cre transgenic mice. Palate development was normal in pan-neuronal β3 knockouts but ~61% died as neonates. Survivors were overtly normal, fertile, and were less sensitive to etomidate. Forebrain selective knockout of β3 was achieved using α CamKII-cre transgenic mice. Palate development was normal in forebrain selective β3 knockout mice. These knockouts survived the neonatal period, but ~30% died between 15–25 days of age. Survivors had reduced reproductive fitness, reduced sensitivity to etomidate, were hyperactive, and some became obese. Conclusion Conditional inactivation of the β3 gene revealed novel insight into the function of this GABAA-R subunit. The floxed β3 knockout mice described here will be very useful for conditional knockout studies to further investigate the role of the β3 subunit in development, ethanol and anesthetic action, normal physiology, and pathophysiologic processes. PMID:17927825
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Asymmetric top-down modulation of ascending visual pathways in pigeons.
Freund, Nadja; Valencia-Alfonso, Carlos E; Kirsch, Janina; Brodmann, Katja; Manns, Martina; Güntürkün, Onur
2016-03-01
Cerebral asymmetries are a ubiquitous phenomenon evident in many species, incl. humans, and they display some similarities in their organization across vertebrates. In many species the left hemisphere is associated with the ability to categorize objects based on abstract or experience-based behaviors. Using the asymmetrically organized visual system of pigeons as an animal model, we show that descending forebrain pathways asymmetrically modulate visually evoked responses of single thalamic units. Activity patterns of neurons within the nucleus rotundus, the largest thalamic visual relay structure in birds, were differently modulated by left and right hemispheric descending systems. Thus, visual information ascending towards the left hemisphere was modulated by forebrain top-down systems at thalamic level, while right thalamic units were strikingly less modulated. This asymmetry of top-down control could promote experience-based processes within the left hemisphere, while biasing the right side towards stimulus-bound response patterns. In a subsequent behavioral task we tested the possible functional impact of this asymmetry. Under monocular conditions, pigeons learned to discriminate color pairs, so that each hemisphere was trained on one specific discrimination. Afterwards the animals were presented with stimuli that put the hemispheres in conflict. Response patterns on the conflicting stimuli revealed a clear dominance of the left hemisphere. Transient inactivation of left hemispheric top-down control reduced this dominance while inactivation of right hemispheric top-down control had no effect on response patterns. Functional asymmetries of descending systems that modify visual ascending pathways seem to play an important role in the superiority of the left hemisphere in experience-based visual tasks. Copyright © 2015. Published by Elsevier Ltd.
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Kawano, Takayuki; Morioka, Motohiro; Yano, Shigetoshi; Hamada, Jun-Ichiro; Ushio, Yukitaka; Miyamoto, Eishichi; Fukunaga, Kohji
2002-08-01
The authors recently reported that sodium orthovanadate rescues cells from delayed neuronal death in gerbil hippocampus after transient forebrain ischemia through phosphatidylinositol 3-kinase-protein kinase B (Akt) pathway (Kawano et al., 2001). In the current study, they demonstrated that the activation of FKHR, a Forkhead transcription factor and a substrate for Akt, preceded delayed neuronal death in CA1 regions after transient forebrain ischemia. Adult Mongolian gerbils were subjected to 5-minute forebrain ischemia. Immunoblotting analysis with anti-phospho-FKHR antibody showed that phosphorylation of FKHR at serine-256 in the CA1 region decreased immediately after and 0.5 and 1 hour after reperfusion. The dephosphorylation of FKHR was correlated with the decreased Akt activity. Intracerebroventricular injection of orthovanadate 30 minutes before ischemia inhibited dephosphorylation of FKHR after reperfusion, and blocked delayed neuronal death in the CA1 region. Gel mobility shift analysis using nuclear extracts from the CA1 region prepared immediately after reperfusion revealed increases in DNA binding activity for the FKHR-responsive element on the Fas ligand promoter. The orthovanadate injection administered before ischemia inhibited its binding activity. Two days after reperfusion, expression of Fas ligand increased in the CA1 region and the orthovanadate injection inhibited this increased expression. These results suggest that the inactivation of Akt results in the activation of FKHR and, in turn, relates to the expression of Fas ligand in the CA1 region after transient forebrain ischemia.
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Myer, Catherine E; Bryant, Deborah; DeLuca, John; Gluck, Mark A
2002-01-01
In humans, anterograde amnesia can result from damage to the medial temporal (MT) lobes (including hippocampus), as well as to other brain areas such as basal forebrain. Results from animal classical conditioning studies suggest that there may be qualitative differences in the memory impairment following MT vs. basal forebrain damage. Specifically, delay eyeblink conditioning is spared after MT damage in animals and humans, but impaired in animals with basal forebrain damage. Recently, we have likewise shown delay eyeblink conditioning impairment in humans with amnesia following anterior communicating artery (ACoA) aneurysm rupture, which damages the basal forebrain. Another associative learning task, a computer-based concurrent visual discrimination, also appears to be spared in MT amnesia while ACoA amnesics are slower to learn the discriminations. Conversely, animal and computational models suggest that, even though MT amnesics may learn quickly, they may learn qualitatively differently from controls, and these differences may result in impaired transfer when familiar information is presented in novel combinations. Our initial data suggests such a two-phase learning and transfer task may provide a double dissociation between MT amnesics (spared initial learning but impaired transfer) and ACoA amnesics (slow initial learning but spared transfer). Together, these emerging data suggest that there are subtle but dissociable differences in the amnesic syndrome following damage to the MT lobes vs. basal forebrain, and that these differences may be most visible in non-declarative tasks such as eyeblink classical conditioning and simple associative learning.
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Rajadhyaksha, Anjali M.; Ra, Stephen; Kishinevsky, Sarah; Lee, Anni S.; Romanienko, Peter; DuBoff, Mariel; Yang, Chingwen; Zupan, Bojana; Byrne, Maureen; Daruwalla, Zeeba R.; Mark, Willie; Kosofsky, Barry E.; Toth, Miklos; Higgins, Joseph J.
2018-01-01
A nonsense mutation in the human cereblon gene (CRBN) causes a mild type of autosomal recessive non-syndromic intellectual disability (ID). Animal studies show that crbn is a cytosolic protein with abundant expression in the hippocampus (HPC) and neocortex (CTX). Its diverse functions include the developmental regulation of ion channels at the neuronal synapse, the mediation of developmental programs by ubiquitination, and a target for herpes simplex type I virus in HPC neurons. To test the hypothesis that anomalous CRBN expression leads to HPC-mediated memory and learning deficits, we generated germ-line crbn knock-out mice (crbn−/−). We also inactivated crbn in forebrain neurons in conditional knock-out mice in which crbn exons 3 and 4 are deleted by cre recombinase under the direction of the Ca2+/calmodulin-dependent protein kinase II alpha promoter (CamKIIcre/+, crbn−/−). crbn mRNA levels were negligible in the HPC, CTX, and cerebellum (CRBM) of the crbn−/− mice. In contrast, crbn mRNA levels were reduced 3- to 4-fold in the HPC, CTX but not in the CRBM in CamKIIcre/+, crbn−/− mice as compared to wild type (CamKIIcre/+, crbn+/+). Contextual fear conditioning showed a significant decrease in the percentage of freezing time in CamKIIcre/+, crbn−/− and crbn−/− mice while motor function, exploratory motivation, and anxiety-related behaviors were normal. These findings suggest that CamKIIcre/+, crbn−/− mice exhibit selective HPC-dependent deficits in associative learning and supports the use of these mice as in vivo models to study the functional consequences of CRBN aberrations on memory and learning in humans. PMID:21995942
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Scholpp, Steffen; Brand, Michael
2003-11-01
Initial anterior-posterior patterning of the neural tube into forebrain, midbrain, and hindbrain primordia occurs already during gastrulation, in response to signals patterning the gastrula embryo. After the initial establishment, further development within each brain part is thought to proceed largely independently of the others. However, mechanisms should exist that ensure proper delineation of brain subdivisions also at later stages; such mechanisms are, however, poorly understood. In zebrafish no isthmus mutant embryos, inactivation of the pax2.1 gene leads to a failure of the midbrain and isthmus primordium to develop normally from the gastrula stage onward (Lun and Brand [1998] Development 125:3049-3062). Here, we report that, after the initially correct establishment during gastrulation stages, the neighbouring forebrain primordium and, partially, the hindbrain primordium expand into the misspecified midbrain territory in no isthmus mutant embryos. The expansion is particularly evident for the posterior part of the diencephalon and less so for the first rhombomeric segment, the territories immediately abutting the midbrain/isthmus primordium. The nucleus of the posterior commissure is expanded in size, and marker genes of the forebrain and rhombomere 1 expand progressively into the misspecified midbrain primordium, eventually resulting in respecification of the midbrain primordium. We therefore suggest that the genetic program controlled by Pax2.1 is not only involved in initiating but also in maintaining the identity of midbrain and isthmus cells to prevent them from assuming a forebrain or hindbrain fate. Copyright 2003 Wiley-Liss, Inc.
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Latapy, Camille; Rioux, Véronique; Guitton, Matthieu J.; Beaulieu, Jean-Martin
2012-01-01
Serotonin (5-HT) neurotransmission is thought to underlie mental illnesses, such as bipolar disorder, depression, autism and schizophrenia. Independent studies have indicated that 5-HT or drugs acting on 5-HT neurotransmission regulate the serine/threonine kinase glycogen synthase kinase 3β (GSK3β). Furthermore, GSK3β inhibition rescues behavioural abnormalities in 5-HT-deficient mice with a loss-of-function mutation equivalent to the human variant (R441H) of tryptophan hydroxylase 2. In an effort to define neuroanatomical correlates of GSK3β activity in the regulation of behaviour, we generated CamKIIcre-floxGSK3β mice in which the gsk3b gene is postnatally inactivated in forebrain pyramidal neurons. Behavioural characterization showed that suppression of GSK3β in these brain areas has anxiolytic and pro-social effects. However, while a global reduction of GSK2β expression reduced responsiveness to amphetamine and increased resilience to social defeat, these behavioural effects were not found in CamKIIcre-floxGSK3β mice. These findings demonstrate a dissociation of behavioural effects related to GSK3 inhibition, with forebrain GSK3β being involved in the regulation of anxiety and sociability while social preference, resilience and responsiveness to psychostimulants would involve a function of this kinase in subcortical areas such as the hippocampus and striatum. PMID:22826345
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Interactions between prefrontal cortex and cerebellum revealed by trace eyelid conditioning.
Kalmbach, Brian E; Ohyama, Tatsuya; Kreider, Joy C; Riusech, Frank; Mauk, Michael D
2009-01-01
Eyelid conditioning has proven useful for analysis of learning and computation in the cerebellum. Two variants, delay and trace conditioning, differ only by the relative timing of the training stimuli. Despite the subtlety of this difference, trace eyelid conditioning is prevented by lesions of the cerebellum, hippocampus, or medial prefrontal cortex (mPFC), whereas delay eyelid conditioning is prevented by cerebellar lesions and is largely unaffected by forebrain lesions. Here we test whether these lesion results can be explained by two assertions: (1) Cerebellar learning requires temporal overlap between the mossy fiber inputs activated by the tone conditioned stimulus (CS) and the climbing fiber inputs activated by the reinforcing unconditioned stimulus (US), and therefore (2) trace conditioning requires activity that outlasts the presentation of the CS in a subset of mossy fibers separate from those activated directly by the CS. By use of electrical stimulation of mossy fibers as a CS, we show that cerebellar learning during trace eyelid conditioning requires an input that persists during the stimulus-free trace interval. By use of reversible inactivation experiments, we provide evidence that this input arises from the mPFC and arrives at the cerebellum via a previously unidentified site in the pontine nuclei. In light of previous PFC recordings in various species, we suggest that trace eyelid conditioning involves an interaction between the persistent activity of delay cells in mPFC-a putative mechanism of working memory-and motor learning in the cerebellum.
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The dopaminergic projection system, basal forebrain macrosystems, and conditioned stimuli
Zahm, Daniel S.
2011-01-01
This review begins with a description of some problems that in recent years have beset an influential circuit model of fear-conditioning and goes on to look at neuroanatomy that might subserve conditioning viewed in a broader perspective, including not only fear, but also appetitive, conditioning. The paper then focuses on basal forebrain functional-anatomical systems, or macrosystems, as they have come to be called, which Lennart Heimer and colleagues described beginning in the 1970’s. Yet more specific attention is then given to the relationships of the dorsal and ventral striatopallidal systems and extended amygdala with the dopaminergic mesotelencephalic projection systems, culminating with the hypothesis that all macrosystems contribute to behavioral conditioning. PMID:18204412
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NCAM deficiency in the mouse forebrain impairs innate and learned avoidance behaviours.
Brandewiede, J; Stork, O; Schachner, M
2014-06-01
The neural cell adhesion molecule (NCAM) has been implicated in the development and plasticity of neural circuits and the control of hippocampus- and amygdala-dependent learning and behaviour. Previous studies in constitutive NCAM null mutants identified emotional behaviour deficits related to disturbances of hippocampal and amygdala functions. Here, we studied these behaviours in mice conditionally deficient in NCAM in the postmigratory forebrain neurons. We report deficits in both innate and learned avoidance behaviours, as observed in elevated plus maze and passive avoidance tasks. In contrast, general locomotor activity, trait anxiety or neophobia were unaffected by the mutation. Altered avoidance behaviour of the conditional NCAM mutants was associated with a deficit in serotonergic signalling, as indicated by their reduced responsiveness to (±)-8-hydroxy-2-(dipropylamino)-tetralin-induced hypothermia. Another serotonin-dependent behaviour, namely intermale aggression that is massively increased in constitutively NCAM-deficient mice, was not affected in the forebrain-specific mutants. Our data suggest that genetically or environmentally induced changes of NCAM expression in the late postnatal and mature forebrain determine avoidance behaviour and serotonin (5-HT)1A receptor signalling. © 2014 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.
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Secreted Metalloproteinase ADAMTS-3 Inactivates Reelin.
Ogino, Himari; Hisanaga, Arisa; Kohno, Takao; Kondo, Yuta; Okumura, Kyoko; Kamei, Takana; Sato, Tempei; Asahara, Hiroshi; Tsuiji, Hitomi; Fukata, Masaki; Hattori, Mitsuharu
2017-03-22
The secreted glycoprotein Reelin regulates embryonic brain development and adult brain functions. It has been suggested that reduced Reelin activity contributes to the pathogenesis of several neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease; however, noninvasive methods that can upregulate Reelin activity in vivo have yet to be developed. We previously found that the proteolytic cleavage of Reelin within Reelin repeat 3 (N-t site) abolishes Reelin activity in vitro , but it remains controversial as to whether this effect occurs in vivo Here we partially purified the enzyme that mediates the N-t cleavage of Reelin from the culture supernatant of cerebral cortical neurons. This enzyme was identified as a disintegrin and metalloproteinase with thrombospondin motifs-3 (ADAMTS-3). Recombinant ADAMTS-3 cleaved Reelin at the N-t site. ADAMTS-3 was expressed in excitatory neurons in the cerebral cortex and hippocampus. N-t cleavage of Reelin was markedly decreased in the embryonic cerebral cortex of ADAMTS-3 knock-out (KO) mice. Importantly, the amount of Dab1 and the phosphorylation level of Tau, which inversely correlate with Reelin activity, were significantly decreased in the cerebral cortex of ADAMTS-3 KO mice. Conditional KO mice, in which ADAMTS-3 was deficient only in the excitatory neurons of the forebrain, showed increased dendritic branching and elongation in the postnatal cerebral cortex. Our study shows that ADAMTS-3 is the major enzyme that cleaves and inactivates Reelin in the cerebral cortex and hippocampus. Therefore, inhibition of ADAMTS-3 may be an effective treatment for neuropsychiatric and neurodegenerative disorders. SIGNIFICANCE STATEMENT ADAMTS-3 was identified as the protease that cleaves and inactivates Reelin in the cerebral cortex and hippocampus. ADAMTS-3 was expressed in the excitatory neurons of the embryonic and postnatal cerebral cortex and hippocampus. Cleavage by ADAMTS-3 is the major contributor of Reelin inactivation in vivo Tau phosphorylation was decreased and dendritic branching and elongation was increased in ADAMTS-3-deficient mice. Therefore, inhibition of ADAMTS-3 upregulates Reelin activity and may be a potential therapeutic strategy for the prevention or treatment of neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease. Copyright © 2017 the authors 0270-6474/17/373181-11$15.00/0.
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Bertocchi, Ilaria; Oberto, Alessandra; Longo, Angela; Mele, Paolo; Sabetta, Marianna; Bartolomucci, Alessandro; Palanza, Paola; Sprengel, Rolf; Eva, Carola
2011-01-01
Neuropeptide Y (NPY) plays an important role in stress, anxiety, obesity, and energy homeostasis via activation of NPY-Y1 receptors (Y1Rs) in the brain. However, global knockout of the Npy1r gene has low or no impact on anxiety and body weight. To uncover the role of limbic Y1Rs, we generated conditional knockout mice in which the inactivation of the Npy1r gene was restricted to excitatory neurons of the forebrain, starting from juvenile stages (Npy1rrfb). Npy1rrfb mice exhibited increased anxiety and reduced body weight, less adipose tissue, and lower serum leptin levels. Npy1rrfb mutants also had a hyperactive hypothalamic–pituitary–adrenocortical axis, as indicated by higher peripheral corticosterone and higher density of NPY immunoreactive fibers and corticotropin releasing hormone immunoreactive cell bodies in the paraventricular hypothalamic nucleus. Importantly, through fostering experiments, we determined that differences in phenotype between Npy1rrfb and Npy1r2lox mice became apparent when both genotypes were raised by FVB/J but not by C57BL/6J dams, suggesting that limbic Y1Rs are key targets of maternal care-induced programming of anxiety and energy homeostasis. PMID:22084082
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Forebrain neurogenesis: From embryo to adult.
Dennis, Daniel; Picketts, David; Slack, Ruth S; Schuurmans, Carol
2016-01-01
A satellite symposium to the Canadian Developmental Biology Conference 2016 was held on March 16-17, 2016 in Banff, Alberta, Canada, entitled Forebrain Neurogenesis : From embryo to adult . The Forebrain Neurogenesis symposium was a focused, high-intensity meeting, bringing together the top Canadian and international researchers in the field. This symposium reported the latest breaking news, along with 'state of the art' techniques to answer fundamental questions in developmental neurobiology. Topics covered ranged from stem cell regulation to neurocircuitry development, culminating with a session focused on neuropsychiatric disorders. Understanding the underlying causes of neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD) is of great interest as diagnoses of these conditions are climbing at alarming rates. For instance, in 2012, the Centers for Disease Control reported that the prevalence rate of ASD in the U.S. was 1 in 88; while more recent data indicate that the number is as high as 1 in 68 (Centers for Disease Control and Prevention MMWR Surveillance Summaries. Vol. 63. No. 2). Similarly, the incidence of ASD is on the rise in Canada, increasing from 1 in 150 in 2000 to 1 in 63 in 2012 in southeastern Ontario (Centers for Disease Control and Prevention). Currently very little is known regarding the deficits underlying these neurodevelopmental conditions. Moreover, the development of effective therapies is further limited by major gaps in our understanding of the fundamental processes that regulate forebrain development and adult neurogenesis. The Forebrain Neurogenesis satellite symposium was thus timely, and it played a key role in advancing research in this important field, while also fostering collaborations between international leaders, and inspiring young researchers.
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Basso, Julia C; Morrell, Joan I
2015-08-01
Voluntary wheel running in rats provides a preclinical model of exercise motivation in humans. We hypothesized that rats run because this activity has positive incentive salience in both the acquisition and habitual stages of wheel running and that gender differences might be present. Additionally, we sought to determine which forebrain regions are essential for the motivational processes underlying wheel running in rats. The motivation for voluntary wheel running in male and female Sprague-Dawley rats was investigated during the acquisition (Days 1-7) and habitual phases (after Day 21) of running using conditioned place preference (CPP) and the reinstatement (rebound) response after forced abstinence, respectively. Both genders displayed a strong CPP for the acquisition phase and a strong rebound response to wheel deprivation during the habitual phase, suggesting that both phases of wheel running are rewarding for both sexes. Female rats showed a 1.5 times greater rebound response than males to wheel deprivation in the habitual phase of running, while during the acquisition phase, no gender differences in CPP were found. We transiently inactivated the medial prefrontal cortex (mPFC) or the nucleus accumbens (NA), hypothesizing that because these regions are involved in the acquisition and reinstatement of self-administration of both natural and pharmacological stimuli, they might also serve a role in the motivation to wheel run. Inactivation of either structure decreased the rebound response in the habitual phase of running, demonstrating that these structures are involved in the motivation for this behavior. (c) 2015 APA, all rights reserved).
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Loss of embryonic MET signaling alters profiles of hippocampal interneurons.
Martins, Gabriela J; Plachez, Céline; Powell, Elizabeth M
2007-01-01
Hippocampal interneurons arise in the ventral forebrain and migrate dorsally in response to cues, including hepatocyte growth factor/scatter factor which signals via its receptor MET. Examination of the hippocampus in adult mice in which MET had been inactivated in the embryonic proliferative zones showed an increase in parvalbumin-expressing cells in the dentate gyrus, but a loss of these cells in the CA3 region. An overall loss of calretinin-expressing cells was seen throughout the hippocampus. A similar CA3 deficit of parvalbumin and calretinin cells was observed when MET was eliminated only in postmitotic cells. These data suggest that MET is required for the proper hippocampal development, and embryonic perturbations lead to long-term anatomical defects with possible learning and memory dysfunction.
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Brown, Ritchie E.; Hussain Shuler, Marshall G.; Petersen, Carl C.H.; Kepecs, Adam
2015-01-01
The basal forebrain (BF) houses major ascending projections to the entire neocortex that have long been implicated in arousal, learning, and attention. The disruption of the BF has been linked with major neurological disorders, such as coma and Alzheimer's disease, as well as in normal cognitive aging. Although it is best known for its cholinergic neurons, the BF is in fact an anatomically and neurochemically complex structure. Recent studies using transgenic mouse lines to target specific BF cell types have led to a renaissance in the study of the BF and are beginning to yield new insights about cell-type-specific circuit mechanisms during behavior. These approaches enable us to determine the behavioral conditions under which cholinergic and noncholinergic BF neurons are activated and how they control cortical processing to influence behavior. Here we discuss recent advances that have expanded our knowledge about this poorly understood brain region and laid the foundation for future cell-type-specific manipulations to modulate arousal, attention, and cortical plasticity in neurological disorders. SIGNIFICANCE STATEMENT Although the basal forebrain is best known for, and often equated with, acetylcholine-containing neurons that provide most of the cholinergic innervation of the neocortex, it is in fact an anatomically and neurochemically complex structure. Recent studies using transgenic mouse lines to target specific cell types in the basal forebrain have led to a renaissance in this field and are beginning to dissect circuit mechanisms in the basal forebrain during behavior. This review discusses recent advances in the roles of basal forebrain cholinergic and noncholinergic neurons in cognition via their dynamic modulation of cortical activity. PMID:26468190
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The effects of increasing PGE2 on translocation of labeled albumin into rat brain.
Messripour, M; Mesripour, A; Mashayekhie, F J
2015-01-01
Under pathophysiological conditions, infiltration of leukocyte plays a key role in the progression of the neuroinflammatory reaction in the CNS. Prostaglandin E2 (PGE2) is known to accumulate at lesion sites of the post-ischemic brain. Although post-ischemic treatments with cyclooxygenase-2 inhibitors reduce blood-brain barrier (BBB) leukocyte infiltration, the direct effect of PGE2 on BBB has not been fully implemented. Therefore, the direct effect of increasing PGE2 infusion on translocation of labeled albumin into the brain was assessed. Under anesthesia rats were drilled stereo-taxicaly a burr hole in the right forebrain and PGE2 was infused into the forebrain and the hole was occluded. The animals were then injected with fluorescent labeled albumin (FA), via internal right jugular vein and decapitated at different infusion time points. The forebrain was removed and each forebrain hemisphere was homogenized and fluorescence intensities were measured in the supernatant. The fluorescence intensities measured in the right and left forebrain hemispheres of the control group (0.0 μg PGE2) were almost identical. Four hours after infusion of PGE2 at doses higher than 250 μg, fluorescence intensity increased in the right forebrain supernatant, even if it was not statistically significant. The fluorescence intensity was detectable in the brain supernatant 4 h after infusion of PGE2 in doses higher than 250 μg PGE2. The highest fluorescence intensity was 16 h after infusion of 500 μg PGE2, which returned to near control values after 48 h. Increased fluorescence intensity in the brain following PGE2 infusion is concluded to be associated with disruption of the BBB.
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2010-01-01
Background The bed nucleus of stria terminalis (BNST) is a limbic forebrain structure involved in hypothalamo-pituitary-adrenal axis regulation and stress adaptation. Inappropriate adaptation to stress is thought to compromise the organism's coping mechanisms, which have been implicated in the neurobiology of depression. However, the studies aimed at investigating BNST involvement in depression pathophysiology have yielded contradictory results. Therefore, the objective of the present study was to investigate the effects of temporary acute inactivation of synaptic transmission in the BNST by local microinjection of cobalt chloride (CoCl2) in rats subjected to the forced swimming test (FST). Methods Rats implanted with cannulae aimed at the BNST were submitted to 15 min of forced swimming (pretest). Twenty-four hours later immobility time was registered in a new 5 min forced swimming session (test). Independent groups of rats received bilateral microinjections of CoCl2 (1 mM/100 nL) before or immediately after pretest or before the test session. Additional groups received the same treatment and were submitted to the open field test to control for unspecific effects on locomotor behavior. Results CoCl2 injection into the BNST before either the pretest or test sessions reduced immobility in the FST, suggesting an antidepressant-like effect. No significant effect of CoCl2 was observed when it was injected into the BNST immediately after pretest. In addition, no effect of BNST inactivation was observed in the open field test. Conclusion These results suggest that acute reversible inactivation of synaptic transmission in the BNST facilitates adaptation to stress and induces antidepressant-like effects. PMID:20515458
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Multiple receptors coupled to phospholipase C gate long-term depression in visual cortex.
Choi, Se-Young; Chang, Jeff; Jiang, Bin; Seol, Geun-Hee; Min, Sun-Seek; Han, Jung-Soo; Shin, Hee-Sup; Gallagher, Michela; Kirkwood, Alfredo
2005-12-07
Long-term depression (LTD) in sensory cortices depends on the activation of NMDA receptors. Here, we report that in visual cortical slices, the induction of LTD (but not long-term potentiation) also requires the activation of receptors coupled to the phospholipase C (PLC) pathway. Using immunolesions in combination with agonists and antagonists, we selectively manipulated the activation of alpha1 adrenergic, M1 muscarinic, and mGluR5 glutamatergic receptors. Inactivation of these PLC-coupled receptors prevents the induction of LTD, but only when the three receptors were inactivated together. LTD is fully restored by activating any one of them or by supplying intracellular D-myo-inositol-1,4,5-triphosphate (IP3). LTD was also impaired by intracellular application of PLC or IP3 receptor blockers, and it was absent in mice lacking PLCbeta1, the predominant PLC isoform in the forebrain. We propose that visual cortical LTD requires a minimum of PLC activity that can be supplied independently by at least three neurotransmitter systems. This essential requirement places PLC-linked receptors in a unique position to control the induction of LTD and provides a mechanism for gating visual cortical plasticity via extra-retinal inputs in the intact organism.
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Chan, W Y; Ng, T B; Lam, Joyce S Y; Wong, Jack H; Chu, K T; Ngai, P H K; Lam, S K; Wang, H X
2010-01-01
Earlier investigations disclose that some plant ribosome-inactivating proteins (RIPs) adversely affect mouse embryonic development. In the present study, a mushroom RIP, namely lyophyllin from Lyophyllum shimeji, was isolated, partially sequenced, and its translation inhibitory activity determined. Its teratogenicity was studied by using a technique entailing microinjection and postimplantation whole-embryo culture. It was found that embryonic abnormalities during the period of organogenesis from E8.5 to E9.5 were induced by lyophyllin at a concentration as low as 50 microg/ml, and when the lyophyllin concentration was raised, the number of abnormal embryos increased, the final somite number decreased, and the abnormalities increased in severity. The affected embryonic structures included the cranial neural tube, forelimb buds, branchial arches, and body axis, while optic and otic placodes were more resistant. Lyophyllin at a concentration higher than 500 microg/ml also induced forebrain blisters within the cranial mesenchyme. When the abnormal embryos were examined histologically, an increase of cell death was found to be associated with abnormal structures, indicating that cell death may be one of the underlying causes of teratogenicity of the mushroom RIP. This constitutes the first report on the teratogenicity of a mushroom RIP.
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Volume of the human septal forebrain region is a predictor of source memory accuracy.
Butler, Tracy; Blackmon, Karen; Zaborszky, Laszlo; Wang, Xiuyuan; DuBois, Jonathan; Carlson, Chad; Barr, William B; French, Jacqueline; Devinsky, Orrin; Kuzniecky, Ruben; Halgren, Eric; Thesen, Thomas
2012-01-01
Septal nuclei, components of basal forebrain, are strongly and reciprocally connected with hippocampus, and have been shown in animals to play a critical role in memory. In humans, the septal forebrain has received little attention. To examine the role of human septal forebrain in memory, we acquired high-resolution magnetic resonance imaging scans from 25 healthy subjects and calculated septal forebrain volume using recently developed probabilistic cytoarchitectonic maps. We indexed memory with the California Verbal Learning Test-II. Linear regression showed that bilateral septal forebrain volume was a significant positive predictor of recognition memory accuracy. More specifically, larger septal forebrain volume was associated with the ability to recall item source/context accuracy. Results indicate specific involvement of septal forebrain in human source memory, and recall the need for additional research into the role of septal nuclei in memory and other impairments associated with human diseases.
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Krabbe, Christina; Bak, Sara Thornby; Jensen, Pia; von Linstow, Christian; Martínez Serrano, Alberto; Hansen, Claus; Meyer, Morten
2014-01-01
Neural stem cells (NSCs) constitute a promising source of cells for transplantation in Parkinson's disease (PD), but protocols for controlled dopaminergic differentiation are not yet available. Here we investigated the influence of oxygen on dopaminergic differentiation of human fetal NSCs derived from the midbrain and forebrain. Cells were differentiated for 10 days in vitro at low, physiological (3%) versus high, atmospheric (20%) oxygen tension. Low oxygen resulted in upregulation of vascular endothelial growth factor and increased the proportion of tyrosine hydroxylase-immunoreactive (TH-ir) cells in both types of cultures (midbrain: 9.1±0.5 and 17.1±0.4 (P<0.001); forebrain: 1.9±0.4 and 3.9±0.6 (P<0.01) percent of total cells). Regardless of oxygen levels, the content of TH-ir cells with mature neuronal morphologies was higher for midbrain as compared to forebrain cultures. Proliferative Ki67-ir cells were found in both types of cultures, but the relative proportion of these cells was significantly higher for forebrain NSCs cultured at low, as compared to high, oxygen tension. No such difference was detected for midbrain-derived cells. Western blot analysis revealed that low oxygen enhanced β-tubulin III and GFAP expression in both cultures. Up-regulation of β-tubulin III was most pronounced for midbrain cells, whereas GFAP expression was higher in forebrain as compared to midbrain cells. NSCs from both brain regions displayed less cell death when cultured at low oxygen tension. Following mictrotransplantation into mouse striatal slice cultures predifferentiated midbrain NSCs were found to proliferate and differentiate into substantial numbers of TH-ir neurons with mature neuronal morphologies, particularly at low oxygen. In contrast, predifferentiated forebrain NSCs microtransplanted using identical conditions displayed little proliferation and contained few TH-ir cells, all of which had an immature appearance. Our data may reflect differences in dopaminergic differentiation capacity and region-specific requirements of NSCs, with the dopamine-depleted striatum cultured at low oxygen offering an attractive micro-environment for midbrain NSCs. PMID:24788190
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Toth, Mate; Gresack, Jodi E; Bangasser, Debra A; Plona, Zach; Valentino, Rita J; Flandreau, Elizabeth I; Mansuy, Isabelle M; Merlo-Pich, Emilio; Geyer, Mark A; Risbrough, Victoria B
2014-05-01
Corticotropin releasing factor (CRF) regulates physiological and behavioral responses to stress. Trauma in early life or adulthood is associated with increased CRF in the cerebrospinal fluid and heightened anxiety. Genetic variance in CRF receptors is linked to altered risk for stress disorders. Thus, both heritable differences and environmentally induced changes in CRF neurotransmission across the lifespan may modulate anxiety traits. To test the hypothesis that CRF hypersignaling is sufficient to modify anxiety-related phenotypes (avoidance, startle, and conditioned fear), we induced transient forebrain-specific overexpression of CRF (CRFOE) in mice (1) during development to model early-life stress, (2) in adulthood to model adult-onset stress, or (3) across the entire postnatal lifespan to model heritable increases in CRF signaling. The consequences of these manipulations on CRF peptide levels and behavioral responses were examined in adulthood. We found that transient CRFOE during development decreased startle habituation and prepulse inhibition, and increased avoidance (particularly in females) recapitulating the behavioral effects of lifetime CRFOE despite lower CRF peptide levels at testing. In contrast, CRFOE limited to adulthood reduced contextual fear learning in females and increased startle reactivity in males but did not change avoidance or startle plasticity. These findings suggest that forebrain CRFOE limited to development is sufficient to induce enduring alterations in startle plasticity and anxiety, while forebrain CRFOE during adulthood results in a different phenotype profile. These findings suggest that startle circuits are particularly sensitive to forebrain CRFOE, and that the impact of CRFOE may be dependent on the time of exposure.
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Kazdoba, Tatiana M; Sunnen, C Nicole; Crowell, Beth; Lee, Gum Hwa; Anderson, Anne E; D'Arcangelo, Gabriella
2012-01-01
The phosphatase and tensin homolog located on chromosome 10 (PTEN) suppresses the activity of the phosphoinositide-3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway, a signaling cascade critically involved in the regulation of cell proliferation and growth. Human patients carrying germ line PTEN mutations have an increased predisposition to tumors, and also display a variety of neurological symptoms and increased risk of epilepsy and autism, implicating PTEN in neuronal development and function. Consistently, loss of Pten in mouse neural cells results in ataxia, seizures, cognitive abnormalities, increased soma size and synaptic abnormalities. To better understand how Pten regulates the excitability of principal forebrain neurons, a factor that is likely to be altered in cognitive disorders, epilepsy and autism, we generated a novel conditional knockout mouse line (NEX-Pten) in which Cre, under the control of the NEX promoter, drives the deletion of Pten specifically in early postmitotic, excitatory neurons of the developing forebrain. Homozygous mutant mice exhibited a massive enlargement of the forebrain, and died shortly after birth due to excessive mTOR activation. Analysis of the neonatal cerebral cortex further identified molecular defects resulting from Pten deletion that likely affect several aspects of neuronal development and excitability. Copyright © 2012 S. Karger AG, Basel.
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do Carmo, J M; da Silva, A A; Sessums, P O; Ebaady, S H; Pace, B R; Rushing, J S; Davis, M T; Hall, J E
2014-06-01
We examined whether deficiency of Src homology 2 containing phosphatase (Shp2) signaling in forebrain neurons alters metabolic and cardiovascular regulation under various conditions and if it attenuates the anorexic and cardiovascular effects of leptin. We also tested whether forebrain Shp2 deficiency alters blood pressure (BP) and heart rate (HR) responses to acute stress. Forebrain Shp2(-/-) mice were generated by crossing Shp2(flox/flox) mice with CamKIIα-cre mice. At 22-24 weeks of age, the mice were instrumented for telemetry for measurement of BP, HR and body temperature (BT). Oxygen consumption (VO2), energy expenditure and motor activity were monitored by indirect calorimetry. Shp2/CamKIIα-cre mice were heavier (46±3 vs 32±1 g), hyperglycemic, hyperleptinemic, hyperinsulinemic and hyperphagic compared to Shp2(flox/flox) control mice. Shp2/CamKIIα-cre mice exhibited reduced food intake responses to fasting/refeeding and impaired regulation of BT when exposed to 15 and 30 °C ambient temperatures. Despite being obese and having many features of metabolic syndrome, Shp2/CamKIIα-cre mice had similar daily average BP and HR compared to Shp2(flox/flox) mice (112±2 vs 113±1 mm Hg and 595±34 vs 650±40 b.p.m.), but exhibited increased BP and HR responses to cold exposure and acute air-jet stress test. Leptin's ability to reduce food intake and to raise BP were markedly attenuated in Shp2/CamKIIα-cre mice. These results suggest that forebrain Shp2 signaling regulates food intake, appetite responses to caloric deprivation and thermogenic control of body temperature during variations in ambient temperature. Deficiency of Shp2 signaling in the forebrain is associated with augmented cardiovascular responses to cold and acute stress but attenuated BP responses to leptin.
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Rohde, Kristian; Bering, Tenna; Furukawa, Takahisa; Rath, Martin Fredensborg
2017-10-01
The retinal and anterior neural fold homeobox gene (Rax) controls development of the eye and the forebrain. Postnatal expression of Rax in the brain is restricted to the pineal gland, a forebrain structure devoted to melatonin synthesis. The role of Rax in pineal function is unknown. In order to investigate the role of Rax in pineal function while circumventing forebrain abnormalities of the global Rax knockout, we generated an eye and pineal-specific Rax conditional knockout mouse. Deletion of Rax in the pineal gland did not affect morphology of the gland, suggesting that Rax is not essential for pineal gland development. In contrast, deletion of Rax in the eye generated an anophthalmic phenotype. In addition to the loss of central visual pathways, the suprachiasmatic nucleus of the hypothalamus housing the circadian clock was absent, indicating that the retinohypothalamic tract is required for the nucleus to develop. Telemetric analyses confirmed the lack of a functional circadian clock. Arylalkylamine N-acetyltransferase (Aanat) transcripts, encoding the melatonin rhythm-generating enzyme, were undetectable in the pineal gland of the Rax conditional knockout under normal conditions, whereas the paired box 6 homeobox gene, known to regulate pineal development, was up-regulated. By injecting isoproterenol, which mimics a nocturnal situation in the pineal gland, we were able to induce pineal expression of Aanat in the Rax conditional knockout mouse, but Aanat transcript levels were significantly lower than those of Rax-proficient mice. Our data suggest that Rax controls pineal gene expression and via Aanat may modulate melatonin synthesis. © 2017 International Society for Neurochemistry.
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Hambright, William Sealy; Fonseca, Rene Solano; Chen, Liuji; Na, Ren; Ran, Qitao
2017-08-01
Synaptic loss and neuron death are the underlying cause of neurodegenerative diseases such as Alzheimer's disease (AD); however, the modalities of cell death in those diseases remain unclear. Ferroptosis, a newly identified oxidative cell death mechanism triggered by massive lipid peroxidation, is implicated in the degeneration of neurons populations such as spinal motor neurons and midbrain neurons. Here, we investigated whether neurons in forebrain regions (cerebral cortex and hippocampus) that are severely afflicted in AD patients might be vulnerable to ferroptosis. To this end, we generated Gpx4BIKO mouse, a mouse model with conditional deletion in forebrain neurons of glutathione peroxidase 4 (Gpx4), a key regulator of ferroptosis, and showed that treatment with tamoxifen led to deletion of Gpx4 primarily in forebrain neurons of adult Gpx4BIKO mice. Starting at 12 weeks after tamoxifen treatment, Gpx4BIKO mice exhibited significant deficits in spatial learning and memory function versus Control mice as determined by the Morris water maze task. Further examinations revealed that the cognitively impaired Gpx4BIKO mice exhibited hippocampal neurodegeneration. Notably, markers associated with ferroptosis, such as elevated lipid peroxidation, ERK activation and augmented neuroinflammation, were observed in Gpx4BIKO mice. We also showed that Gpx4BIKO mice fed a diet deficient in vitamin E, a lipid soluble antioxidant with anti-ferroptosis activity, had an expedited rate of hippocampal neurodegeneration and behavior dysfunction, and that treatment with a small-molecule ferroptosis inhibitor ameliorated neurodegeneration in those mice. Taken together, our results indicate that forebrain neurons are susceptible to ferroptosis, suggesting that ferroptosis may be an important neurodegenerative mechanism in diseases such as AD. Copyright © 2017. Published by Elsevier B.V.
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Aronov, Dmitriy; Veit, Lena; Goldberg, Jesse H.; Fee, Michale S.
2011-01-01
Accurate timing is a critical aspect of motor control, yet the temporal structure of many mature behaviors emerges during learning from highly variable exploratory actions. How does a developing brain acquire the precise control of timing in behavioral sequences? To investigate the development of timing, we analyzed the songs of young juvenile zebra finches. These highly variable vocalizations, akin to human babbling, gradually develop into temporally-stereotyped adult songs. We find that the durations of syllables and silences in juvenile singing are formed by a mixture of two distinct modes of timing – a random mode producing broadly-distributed durations early in development, and a stereotyped mode underlying the gradual emergence of stereotyped durations. Using lesions, inactivations, and localized brain cooling we investigated the roles of neural dynamics within two premotor cortical areas in the production of these temporal modes. We find that LMAN (lateral magnocellular nucleus of the nidopallium) is required specifically for the generation of the random mode of timing, and that mild cooling of LMAN causes an increase in the durations produced by this mode. On the contrary, HVC (used as a proper name) is required specifically for producing the stereotyped mode of timing, and its cooling causes a slowing of all stereotyped components. These results show that two neural pathways contribute to the timing of juvenile songs, and suggest an interesting organization in the forebrain, whereby different brain areas are specialized for the production of distinct forms of neural dynamics. PMID:22072687
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Mercer, Robert C. C.; Ma, Li; Watts, Joel C.; Strome, Robert; Wohlgemuth, Serene; Yang, Jing; Cashman, Neil R.; Coulthart, Michael B.; Schmitt-Ulms, Gerold; Jhamandas, Jack H.; Westaway, David
2013-01-01
Widely expressed in the adult central nervous system, the cellular prion protein (PrPC) is implicated in a variety of processes, including neuronal excitability. Dipeptidyl aminopeptidase-like protein 6 (DPP6) was first identified as a PrPC interactor using in vivo formaldehyde cross-linking of wild type (WT) mouse brain. This finding was confirmed in three cell lines and, because DPP6 directs the functional assembly of K+ channels, we assessed the impact of WT and mutant PrPC upon Kv4.2-based cell surface macromolecular complexes. Whereas a Gerstmann-Sträussler-Scheinker disease version of PrP with eight extra octarepeats was a loss of function both for complex formation and for modulation of Kv4.2 channels, WT PrPC, in a DPP6-dependent manner, modulated Kv4.2 channel properties, causing an increase in peak amplitude, a rightward shift of the voltage-dependent steady-state inactivation curve, a slower inactivation, and a faster recovery from steady-state inactivation. Thus, the net impact of wt PrPC was one of enhancement, which plays a critical role in the down-regulation of neuronal membrane excitability and is associated with a decreased susceptibility to seizures. Insofar as previous work has established a requirement for WT PrPC in the Aβ-dependent modulation of excitability in cholinergic basal forebrain neurons, our findings implicate PrPC regulation of Kv4.2 channels as a mechanism contributing to the effects of oligomeric Aβ upon neuronal excitability and viability. PMID:24225951
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Kerbler, Georg M.; Nedelska, Zuzana; Fripp, Jurgen; Laczó, Jan; Vyhnalek, Martin; Lisý, Jiří; Hamlin, Adam S.; Rose, Stephen; Hort, Jakub; Coulson, Elizabeth J.
2015-01-01
The basal forebrain degenerates in Alzheimer’s disease (AD) and this process is believed to contribute to the cognitive decline observed in AD patients. Impairment in spatial navigation is an early feature of the disease but whether basal forebrain dysfunction in AD is responsible for the impaired navigation skills of AD patients is not known. Our objective was to investigate the relationship between basal forebrain volume and performance in real space as well as computer-based navigation paradigms in an elderly cohort comprising cognitively normal controls, subjects with amnestic mild cognitive impairment and those with AD. We also tested whether basal forebrain volume could predict the participants’ ability to perform allocentric- vs. egocentric-based navigation tasks. The basal forebrain volume was calculated from 1.5 T magnetic resonance imaging (MRI) scans, and navigation skills were assessed using the human analog of the Morris water maze employing allocentric, egocentric, and mixed allo/egocentric real space as well as computerized tests. When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity. Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not. This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy. PMID:26441643
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Lelkes, Zoltán; Abdurakhmanova, Shamsiiat; Porkka-Heiskanen, Tarja
2017-09-18
The cholinergic basal forebrain contributes to cortical activation and receives rich innervations from the ascending activating system. It is involved in the mediation of the arousing actions of noradrenaline and histamine. Glutamatergic stimulation in the basal forebrain results in cortical acetylcholine release and suppression of sleep. However, it is not known to what extent the cholinergic versus non-cholinergic basal forebrain projection neurones contribute to the arousing action of glutamate. To clarify this question, we administered N-methyl-D-aspartate (NMDA), a glutamate agonist, into the basal forebrain in intact rats and after destruction of the cholinergic cells in the basal forebrain with 192 immunoglobulin (Ig)G-saporin. In eight Han-Wistar rats with implanted electroencephalogram/electromyogram (EEG/EMG) electrodes and guide cannulas for microdialysis probes, 0.23 μg 192 IgG-saporin was administered into the basal forebrain, while the eight control animals received artificial cerebrospinal fluid. Two weeks later, a microdialysis probe targeted into the basal forebrain was perfused with cerebrospinal fluid on the baseline day and for 3 h with 0.3 mmNMDA on the subsequent day. Sleep-wake activity was recorded for 24 h on both days. NMDA exhibited a robust arousing effect in both the intact and the lesioned rats. Wakefulness was increased and both non-REM and REM sleep were decreased significantly during the 3-h NMDA perfusion. Destruction of the basal forebrain cholinergic neurones did not abolish the wake-enhancing action of NMDA. Thus, the cholinergic basal forebrain structures are not essential for the mediation of the arousing action of glutamate. © 2017 European Sleep Research Society.
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Gaykema, Ronald P A; Goehler, Lisa E
2011-03-01
Immune challenges can lead to marked behavioral changes, including fatigue, reduced social interest, anorexia, and somnolence, but the precise neuronal mechanisms that underlie sickness behavior remain elusive. Part of the neurocircuitry influencing behavior associated with illness likely includes viscerosensory nuclei located in the caudal brainstem, based on findings that inactivation of the dorsal vagal complex (DVC) can prevent social withdrawal. These brainstem nuclei contribute multiple neuronal projections that target different components of autonomic and stress-related neurocircuitry. In particular, catecholaminergic neurons in the ventrolateral medulla (VLM) and DVC target the hypothalamus and drive neuroendocrine responses to immune challenge, but their particular role in sickness behavior is not known. To test whether this catecholamine pathway also mediates sickness behavior, we compared effects of DVC inactivation with targeted lesion of the catecholamine pathway on exploratory behavior, which provides an index of motivation and fatigue, and associated patterns of brain activation assessed by immunohistochemical detection of c-Fos protein. LPS treatment dramatically reduced exploratory behavior, and produced a pattern of increased c-Fos expression in brain regions associated with stress and autonomic adjustments paraventricular hypothalamus (PVN), bed nucleus of the stria terminalis (BST), central amygdala (CEA), whereas activation was reduced in regions involved in exploratory behavior (hippocampus, dorsal striatum, ventral tuberomammillary nucleus, and ventral tegmental area). Both DVC inactivation and catecholamine lesion prevented reductions in exploratory behavior and completely blocked the inhibitory LPS effects on c-Fos expression in the behavior-associated regions. In contrast, LPS-induced activation in the CEA and BST was inhibited by DVC inactivation but not by catecholamine lesion. The findings support the idea that parallel pathways from immune-sensory caudal brainstem sources target distinct populations of forebrain neurons that likely mediate different aspects of sickness. The caudal medullary catecholaminergic projections to the hypothalamus may significantly contribute to brain mechanisms that induce behavioral "fatigue" in the context of physiological stressors. Copyright © 2010 Elsevier Inc. All rights reserved.
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Gaykema, Ronald P.A.; Goehler, Lisa E.
2010-01-01
Immune challenges can lead to marked behavioral changes, including fatigue, reduced social interest, anorexia, and somnolence, but the precise neuronal mechanisms that underlie sickness behavior remain elusive. Part of the neurocircuitry influencing behavior associated with illness likely includes viscerosensory nuclei located in the caudal brainstem, based on findings that inactivation of the dorsal vagal complex (DVC) can prevent social withdrawal. These brainstem nuclei contribute multiple neuronal projections that target different components of autonomic and stress-related neurocircuitry. In particular, catecholaminergic neurons in the ventrolateral medulla (VLM) and DVC target the hypothalamus and drive neuroendocrine responses to immune challenge, but their particular role in sickness behavior is not known. To test whether this catecholamine pathway also mediates sickness behavior, we compared effects of DVC inactivation with targeted lesion of the catecholamine pathway on exploratory behavior, which provides an index of motivation and fatigue, and associated patterns of brain activation assessed by immunohistochemical detection of c-Fos protein. LPS treatment dramatically reduced exploratory behavior, and produced a pattern of increased c-Fos expression in brain regions associated with stress and autonomic adjustments paraventricular hypothalamus (PVN), bed nucleus of the stria terminalis (BST), central amygdala (CEA), whereas activation was reduced in regions involved in exploratory behavior (hippocampus, dorsal striatum, ventral tuberomammillary nucleus, and ventral tegmental area). Both DVC inactivation and catecholamine lesion prevented reductions in exploratory behavior and completely blocked the inhibitory LPS effects on c-Fos expression in the behavior-associated regions. In contrast, LPS-induced activation in the CEA and BST was inhibited by DVC inactivation but not by catecholamine lesion. The findings support the idea that parallel pathways from immune-sensory caudal brainstem sources target distinct populations of forebrain neurons that likely mediate different aspects of sickness. The caudal medullary catecholaminergic projections to the hypothalamus may significantly contribute to brain mechanisms that induce behavioral “fatigue” in the context of physiological stressors. PMID:21075199
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Functional Connectome Analysis of Dopamine Neuron Glutamatergic Connections in Forebrain Regions.
Mingote, Susana; Chuhma, Nao; Kusnoor, Sheila V; Field, Bianca; Deutch, Ariel Y; Rayport, Stephen
2015-12-09
In the ventral tegmental area (VTA), a subpopulation of dopamine neurons express vesicular glutamate transporter 2 and make glutamatergic connections to nucleus accumbens (NAc) and olfactory tubercle (OT) neurons. However, their glutamatergic connections across the forebrain have not been explored systematically. To visualize dopamine neuron forebrain projections and to enable photostimulation of their axons independent of transmitter status, we virally transfected VTA neurons with channelrhodopsin-2 fused to enhanced yellow fluorescent protein (ChR2-EYFP) and used DAT(IREScre) mice to restrict expression to dopamine neurons. ChR2-EYFP-expressing neurons almost invariably stained for tyrosine hydroxylase, identifying them as dopaminergic. Dopamine neuron axons visualized by ChR2-EYFP fluorescence projected most densely to the striatum, moderately to the amygdala and entorhinal cortex (ERC), sparsely to prefrontal and cingulate cortices, and rarely to the hippocampus. Guided by ChR2-EYFP fluorescence, we recorded systematically from putative principal neurons in target areas and determined the incidence and strength of glutamatergic connections by activating all dopamine neuron terminals impinging on recorded neurons with wide-field photostimulation. This revealed strong glutamatergic connections in the NAc, OT, and ERC; moderate strength connections in the central amygdala; and weak connections in the cingulate cortex. No glutamatergic connections were found in the dorsal striatum, hippocampus, basolateral amygdala, or prefrontal cortex. These results indicate that VTA dopamine neurons elicit widespread, but regionally distinct, glutamatergic signals in the forebrain and begin to define the dopamine neuron excitatory functional connectome. Dopamine neurons are important for the control of motivated behavior and are involved in the pathophysiology of several major neuropsychiatric disorders. Recent studies have shown that some ventral midbrain dopamine neurons are capable of glutamate cotransmission. With conditional expression of channelrhodopsin in dopamine neurons, we systematically explored dopamine neuron connections in the forebrain and identified regionally specific dopamine neuron excitatory connections. Establishing that only a subset of forebrain regions receive excitatory connections from dopamine neurons will help to determine the function of dopamine neuron glutamate cotransmission, which likely involves transmission of precise temporal signals and enhancement of the dynamic range of dopamine neuron signals. Copyright © 2015 the authors 0270-6474/15/3516259-13$15.00/0.
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Krupa, D J; Thompson, R F
1995-05-23
The localization of sites of memory formation within the mammalian brain has proven to be a formidable task even for simple forms of learning and memory. Recent studies have demonstrated that reversibly inactivating a localized region of cerebellum, including the dorsal anterior interpositus nucleus, completely prevents acquisition of the conditioned eye-blink response with no effect upon subsequent learning without inactivation. This result indicates that the memory trace for this type of learning is located either (i) within this inactivated region of cerebellum or (ii) within some structure(s) efferent from the cerebellum to which output from the interpositus nucleus ultimately projects. To distinguish between these possibilities, two groups of rabbits were conditioned (by using two conditioning stimuli) while the output fibers of the interpositus (the superior cerebellar peduncle) were reversibly blocked with microinjections of the sodium channel blocker tetrodotoxin. Rabbits performed no conditioned responses during this inactivation training. However, training after inactivation revealed that the rabbits (trained with either conditioned stimulus) had fully learned the response during the previous inactivation training. Cerebellar output, therefore, does not appear to be essential for acquisition of the learned response. This result, coupled with the fact that inactivation of the appropriate region of cerebellum completely prevents learning, provides compelling evidence supporting the hypothesis that the essential memory trace for the classically conditioned eye-blink response is localized within the cerebellum.
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Bmi-1 cooperates with Foxg1 to maintain neural stem cell self-renewal in the forebrain
Fasano, Christopher A.; Phoenix, Timothy N.; Kokovay, Erzsebet; Lowry, Natalia; Elkabetz, Yechiel; Dimos, John T.; Lemischka, Ihor R.; Studer, Lorenz; Temple, Sally
2009-01-01
Neural stem cells (NSCs) persist throughout life in two forebrain areas: the subventricular zone (SVZ) and the hippocampus. Why forebrain NSCs self-renew more extensively than those from other regions remains unclear. Prior studies have shown that the polycomb factor Bmi-1 is necessary for NSC self-renewal and that it represses the cell cycle inhibitors p16, p19, and p21. Here we show that overexpression of Bmi-1 enhances self-renewal of forebrain NSCs significantly more than those derived from spinal cord, demonstrating a regional difference in responsiveness. We show that forebrain NSCs require the forebrain-specific transcription factor Foxg1 for Bmi-1-dependent self-renewal, and that repression of p21 is a focus of this interaction. Bmi-1 enhancement of NSC self-renewal is significantly greater with increasing age and passage. Importantly, when Bmi-1 is overexpressed in cultured adult forebrain NSCs, they expand dramatically and continue to make neurons even after multiple passages, when control NSCs have become restricted to glial differentiation. Together these findings demonstrate the importance of Bmi-1 and Foxg1 cooperation to maintenance of NSC multipotency and self-renewal, and establish a useful method for generating abundant forebrain neurons ex vivo, outside the neurogenic niche. PMID:19270157
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Eye field requires the function of Sfrp1 as a Wnt antagonist.
Kim, Hyung-Seok; Shin, Jimann; Kim, Seok-Hyung; Chun, Hang-Suk; Kim, Jun-Dae; Kim, Young-Seop; Kim, Myoung-Jin; Rhee, Myungchull; Yeo, Sang-Yeob; Huh, Tae-Lin
2007-02-27
Wnts have been shown to provide a posteriorizing signal that has to be repressed in the specification of vertebrate forebrain region. Previous studies have shown that Wnt activation by LiCl treatment causes an expansion of optic stalk and mid-hindbrain boundary, whereas eye and ventral diencephalon in the forebrain region were reduced. However, the molecular mechanism, by which inhibits Wnt activity in the forebrain remains poorly defined. To investigate relationship between forebrain specification and Wnt signaling, the zebrafish homologue of secreted frizzled related protein1 (sfrp1) has been characterized. The transcripts of sfrp1 are detected in the presumptive forebrain at gastrula and in the ventral telencephalon, ventral diencephalon, midbrain and optic vesicles at 24h after postfertilization (hpf). Overexpression of sfrp1 causes an anteriorization of embryo, with enlarged head and reduced posterior structure as in the embryo overexpressing dominant-negative form of Frizzled8a or Dkk1. Its overexpression restored the eye defects in the Wnt8b-overexpressing embryos, but not in the LiCl-treated embryos. These results suggest that Sfrp1 expressed in the forebrain and eye field plays a critical role in the extracellular events of antagonizing Wnt activity for the forebrain specification.
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Zhai, Qian; Lai, Dengming; Cui, Ping; Zhou, Rui; Chen, Qixing; Hou, Jinchao; Su, Yunting; Pan, Libiao; Ye, Hui; Zhao, Jing-Wei; Fang, Xiangming
2017-10-01
Basal forebrain cholinergic neurons are proposed as a major neuromodulatory system in inflammatory modulation. However, the function of basal forebrain cholinergic neurons in sepsis is unknown, and the neural pathways underlying cholinergic anti-inflammation remain unexplored. Animal research. University research laboratory. Male wild-type C57BL/6 mice and ChAT-ChR2-EYFP (ChAT) transgenic mice. The cholinergic neuronal activity of the basal forebrain was manipulated optogenetically. Cecal ligation and puncture was produced to induce sepsis. Left cervical vagotomy and 6-hydroxydopamine injection to the spleen were used. Photostimulation of basal forebrain cholinergic neurons induced a significant decrease in the levels of tumor necrosis factor-α and interleukin-6 in the serum and spleen. When cecal ligation and puncture was combined with left cervical vagotomy in photostimulated ChAT mice, these reductions in tumor necrosis factor-α and interleukin-6 were partly reversed. Furthermore, photostimulating basal forebrain cholinergic neurons induced a large increase in c-Fos expression in the basal forebrain, the dorsal motor nucleus of the vagus, and the ventral part of the solitary nucleus. Among them, 35.2% were tyrosine hydroxylase positive neurons. Furthermore, chemical denervation showed that dopaminergic neurotransmission to the spleen is indispensable for the anti-inflammation. These results are the first to demonstrate that selectively activating basal forebrain cholinergic neurons is sufficient to attenuate systemic inflammation in sepsis. Specifically, photostimulation of basal forebrain cholinergic neurons activated dopaminergic neurons in dorsal motor nucleus of the vagus/ventral part of the solitary nucleus, and this dopaminergic efferent signal was further transmitted by the vagus nerve to the spleen. This cholinergic-to-dopaminergic neural circuitry, connecting central cholinergic neurons to the peripheral organ, might have mediated the anti-inflammatory effect in sepsis.
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Changes in the neural control of a complex motor sequence during learning
Otchy, Timothy M.; Goldberg, Jesse H.; Aronov, Dmitriy; Fee, Michale S.
2011-01-01
The acquisition of complex motor sequences often proceeds through trial-and-error learning, requiring the deliberate exploration of motor actions and the concomitant evaluation of the resulting performance. Songbirds learn their song in this manner, producing highly variable vocalizations as juveniles. As the song improves, vocal variability is gradually reduced until it is all but eliminated in adult birds. In the present study we examine how the motor program underlying such a complex motor behavior evolves during learning by recording from the robust nucleus of the arcopallium (RA), a motor cortex analog brain region. In young birds, neurons in RA exhibited highly variable firing patterns that throughout development became more precise, sparse, and bursty. We further explored how the developing motor program in RA is shaped by its two main inputs: LMAN, the output nucleus of a basal ganglia-forebrain circuit, and HVC, a premotor nucleus. Pharmacological inactivation of LMAN during singing made the song-aligned firing patterns of RA neurons adultlike in their stereotypy without dramatically affecting the spike statistics or the overall firing patterns. Removing the input from HVC, on the other hand, resulted in a complete loss of stereotypy of both the song and the underlying motor program. Thus our results show that a basal ganglia-forebrain circuit drives motor exploration required for trial-and-error learning by adding variability to the developing motor program. As learning proceeds and the motor circuits mature, the relative contribution of LMAN is reduced, allowing the premotor input from HVC to drive an increasingly stereotyped song. PMID:21543758
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ARX/Arx is expressed in germ cells during spermatogenesis in both marsupial and mouse.
Yu, Hongshi; Pask, Andrew J; Hu, Yanqiu; Shaw, Geoff; Renfree, Marilyn B
2014-03-01
The X-linked aristaless gene, ARX, is essential for the development of the gonads, forebrain, olfactory bulb, pancreas, and skeletal muscle in mice and humans. Mutations cause neurological diseases, often accompanied by ambiguous genitalia. There are a disproportionately high number of testis and brain genes on the human and mouse X chromosomes. It is still unknown whether the X chromosome accrued these genes during its evolution or whether genes that find themselves on the X chromosome evolve such roles. ARX was originally autosomal in mammals and remains so in marsupials, whereas in eutherian mammals it translocated to the X chromosome. In this study, we examined autosomal ARX in tammars and compared it with the X-linked Arx in mice. We detected ARX mRNA in the neural cells of the forebrain, midbrain and hindbrain, and olfactory bulbs in developing tammars, consistent with the expression in mice. ARX was detected by RT-PCR and mRNA in situ hybridization in the developing tammar wallaby gonads of both sexes, suggestive of a role in sexual development as in mice. We also detected ARX/Arx mRNA in the adult testis in both tammars and mice, suggesting a potential novel role for ARX/Arx in spermiogenesis. ARX transcripts were predominantly observed in round spermatids. Arx mRNA localization distributions in the mouse adult testis suggest that it escaped meiotic sex chromosome inactivation during spermatogenesis. Our findings suggest that ARX in the therian mammal ancestor already played a role in male reproduction before it was recruited to the X chromosome in eutherians.
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The Structural Connectome of the Human Central Homeostatic Network.
Edlow, Brian L; McNab, Jennifer A; Witzel, Thomas; Kinney, Hannah C
2016-04-01
Homeostatic adaptations to stress are regulated by interactions between the brainstem and regions of the forebrain, including limbic sites related to respiratory, autonomic, affective, and cognitive processing. Neuroanatomic connections between these homeostatic regions, however, have not been thoroughly identified in the human brain. In this study, we perform diffusion spectrum imaging tractography using the MGH-USC Connectome MRI scanner to visualize structural connections in the human brain linking autonomic and cardiorespiratory nuclei in the midbrain, pons, and medulla oblongata with forebrain sites critical to homeostatic control. Probabilistic tractography analyses in six healthy adults revealed connections between six brainstem nuclei and seven forebrain regions, several over long distances between the caudal medulla and cerebral cortex. The strongest evidence for brainstem-homeostatic forebrain connectivity in this study was between the brainstem midline raphe and the medial temporal lobe. The subiculum and amygdala were the sampled forebrain nodes with the most extensive brainstem connections. Within the human brainstem-homeostatic forebrain connectome, we observed that a lateral forebrain bundle, whose connectivity is distinct from that of rodents and nonhuman primates, is the primary conduit for connections between the brainstem and medial temporal lobe. This study supports the concept that interconnected brainstem and forebrain nodes form an integrated central homeostatic network (CHN) in the human brain. Our findings provide an initial foundation for elucidating the neuroanatomic basis of homeostasis in the normal human brain, as well as for mapping CHN disconnections in patients with disorders of homeostasis, including sudden and unexpected death, and epilepsy.
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Cykowski, Matthew D; Takei, Hidehiro; Van Eldik, Linda J; Schmitt, Frederick A; Jicha, Gregory A; Powell, Suzanne Z; Nelson, Peter T
2016-05-01
Transactivating responsive sequence (TAR) DNA-binding protein 43-kDa (TDP-43) pathology has been described in various brain diseases, but the full anatomical distribution and clinical and biological implications of that pathology are incompletely characterized. Here, we describe TDP-43 neuropathology in the basal forebrain, hypothalamus, and adjacent nuclei in 98 individuals (mean age, 86 years; median final mini-mental state examination score, 27). On examination blinded to clinical and pathologic diagnoses, we identified TDP-43 pathology that most frequently involved the ventromedial basal forebrain in 19 individuals (19.4%). As expected, many of these brains had comorbid pathologies including those of Alzheimer disease (AD), Lewy body disease (LBD), and/or hippocampal sclerosis of aging (HS-Aging). The basal forebrain TDP-43 pathology was strongly associated with comorbid HS-Aging (odds ratio = 6.8, p = 0.001), whereas there was no significant association between basal forebrain TDP-43 pathology and either AD or LBD neuropathology. In this sample, there were some cases with apparent preclinical TDP-43 pathology in the basal forebrain that may indicate that this is an early affected area in HS-Aging. We conclude that TDP-43 pathology in the basal forebrain is strongly associated with HS-Aging. These results raise questions about a specific pathogenetic relationship between basal forebrain TDP-43 and non-HS-Aging comorbid diseases (AD and LBD). © 2016 American Association of Neuropathologists, Inc. All rights reserved.
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Takei, Hidehiro; Van Eldik, Linda J.; Schmitt, Frederick A.; Jicha, Gregory A.; Powell, Suzanne Z.; Nelson, Peter T.
2016-01-01
Transactivating responsive sequence (TAR) DNA-binding protein 43-kDa (TDP-43) pathology has been described in various brain diseases, but the full anatomical distribution and clinical and biological implications of that pathology are incompletely characterized. Here, we describe TDP-43 neuropathology in the basal forebrain, hypothalamus, and adjacent nuclei in 98 individuals (mean age, 86 years; median final mini-mental state examination score, 27). On examination blinded to clinical and pathologic diagnoses, we identified TDP-43 pathology that most frequently involved the ventromedial basal forebrain in 19 individuals (19.4%). As expected, many of these brains had comorbid pathologies including those of Alzheimer disease (AD), Lewy body disease (LBD), and/or hippocampal sclerosis of aging (HS-Aging). The basal forebrain TDP-43 pathology was strongly associated with comorbid HS-Aging (odds ratio = 6.8, p = 0.001), whereas there was no significant association between basal forebrain TDP-43 pathology and either AD or LBD neuropathology. In this sample, there were some cases with apparent preclinical TDP-43 pathology in the basal forebrain that may indicate that this is an early affected area in HS-Aging. We conclude that TDP-43 pathology in the basal forebrain is strongly associated with HS-Aging. These results raise questions about a specific pathogenetic relationship between basal forebrain TDP-43 and non-HS-Aging comorbid diseases (AD and LBD). PMID:26971127
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An Evolutionarily Conserved Role of Presenilin in Neuronal Protection in the Aging Drosophila Brain.
Kang, Jongkyun; Shin, Sarah; Perrimon, Norbert; Shen, Jie
2017-07-01
Mutations in the Presenilin genes are the major genetic cause of Alzheimer's disease. Presenilin and Nicastrin are essential components of γ-secretase, a multi-subunit protease that cleaves Type I transmembrane proteins. Genetic studies in mice previously demonstrated that conditional inactivation of Presenilin or Nicastrin in excitatory neurons of the postnatal forebrain results in memory deficits, synaptic impairment, and age-dependent neurodegeneration. The roles of Drosophila Presenilin ( Psn ) and Nicastrin ( Nct ) in the adult fly brain, however, are unknown. To knockdown (KD) Psn or Nct selectively in neurons of the adult brain, we generated multiple shRNA lines. Using a ubiquitous driver, these shRNA lines resulted in 80-90% reduction of mRNA and pupal lethality-a phenotype that is shared with Psn and Nct mutants carrying nonsense mutations. Furthermore, expression of these shRNAs in the wing disc caused notching wing phenotypes, which are also shared with Psn and Nct mutants. Similar to Nct , neuron-specific Psn KD using two independent shRNA lines led to early mortality and rough eye phenotypes, which were rescued by a fly Psn transgene. Interestingly, conditional KD (cKD) of Psn or Nct in adult neurons using the elav-Gal4 and tubulin-Gal80 ts system caused shortened lifespan, climbing defects, increases in apoptosis, and age-dependent neurodegeneration. Together, these findings demonstrate that, similar to their mammalian counterparts, Drosophila Psn and Nct are required for neuronal survival during aging and normal lifespan, highlighting an evolutionarily conserved role of Presenilin in neuronal protection in the aging brain. Copyright © 2017 by the Genetics Society of America.
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CREB binding protein is required for both short-term and long-term memory formation.
Chen, Guiquan; Zou, Xiaoyan; Watanabe, Hirotaka; van Deursen, Jan M; Shen, Jie
2010-09-29
CREB binding protein (CBP) is a transcriptional coactivator with histone acetyltransferase activity. Our prior study suggested that CBP might be a key target of presenilins in the regulation of memory formation and neuronal survival. To elucidate the role of CBP in the adult brain, we generated conditional knock-out (cKO) mice in which CBP is completely inactivated in excitatory neurons of the postnatal forebrain. Histological analysis revealed normal neuronal morphology and absence of age-dependent neuronal degeneration in the CBP cKO cerebral cortex. CBP cKO mice exhibited robust impairment in the formation of spatial, associative, and object-recognition memory. In addition to impaired long-term memory, CBP cKO mice also displayed deficits in short-term associative and object-recognition memory. Administration of a histone deacetylase inhibitor, trichostatin A, rescued the reduction of acetylated histones in the CBP cKO cortex but failed to rescue either short- or long-term memory deficits, suggesting that the memory impairment may not be caused by general reduction of histone acetyltransferase activity in CBP cKO mice. Further microarray and Western analysis showed decreased expression of calcium-calmodulin-dependent kinase isoforms and NMDA and AMPA receptor subunits in the cerebral cortex of CBP cKO mice. Collectively, these findings suggest a crucial role for CBP in the formation of both short- and long-term memory.
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Embryonic ablation of neuronal VGF increases energy expenditure and reduces body weight
Jiang, Cheng; Lin, Wei-Jye; Sadahiro, Masato; Shin, Andrew C.; Buettner, Christoph; Salton, Stephen R.
2016-01-01
Germline ablation of VGF, a secreted neuronal, neuroendocrine, and endocrine peptide precursor, results in lean, hypermetabolic, and infertile adult mice that are resistant to diet-, lesion-, and genetically-induced obesity and diabetes (Hahm et al., 1999, 2002). To assess whether this phenotype is predominantly driven by reduced VGF expression in developing and/or adult neurons, or in peripheral endocrine and neuroendocrine tissues, we generated and analyzed conditional VGF knockout mice, obtained by mating loxP-flanked (floxed) Vgf mice with either pan-neuronal Synapsin-Cre- or forebrain alpha-CaMKII-Cre-recombinase-expressing transgenic mice. Adult male and female mice, with conditional ablation of the Vgf gene in embryonic neurons had significantly reduced body weight, increased energy expenditure, and were resistant to diet-induced obesity. Conditional forebrain postnatal ablation of VGF in male mice, primarily in adult excitatory neurons, had no measurable effect on body weight nor on energy expenditure, but led to a modest increase in adiposity, partially overlapping the effect of AAV-Cre-mediated targeted ablation of VGF in the adult ventromedial hypothalamus and arcuate nucleus of floxed Vgf mice (Foglesong et al., 2016), and also consistent with results of icv delivery of the VGF-derived peptide TLQP-21 to adult mice, which resulted in increased energy expenditure and reduced adiposity (Bartolomucci et al., 2006). Because the lean, hypermetabolic phenotype of germline VGF knockout mice is to a great extent recapitulated in Syn-Cre+/−,Vgfflpflox/flpflox mice, we conclude that the metabolic profile of germline VGF knockout mice is largely the result of VGF ablation in embryonic CNS neurons, rather than peripheral endocrine and/or neuroendocrine cells, and that in forebrain structures such as hypothalamus, VGF and/or VGF-derived peptides play uniquely different roles in the developing and adult nervous system. PMID:28024880
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G protein-gated K+ channel ablation in forebrain pyramidal neurons selectively impairs fear learning
Victoria, Nicole C.; de Velasco, Ezequiel Marron Fernandez; Ostrovskaya, Olga; Metzger, Stefania; Xia, Zhilian; Kotecki, Lydia; Benneyworth, Michael A.; Zink, Anastasia N.; Martemyanov, Kirill A.; Wickman, Kevin
2015-01-01
Background Cognitive dysfunction occurs in many debilitating conditions including Alzheimer’s disease, Down syndrome, schizophrenia, and mood disorders. The dorsal hippocampus is a critical locus of cognitive processes linked to spatial and contextual learning. G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels, which mediate the postsynaptic inhibitory effect of many neurotransmitters, have been implicated in hippocampal-dependent cognition. Available evidence, however, derives primarily from constitutive gain-of-function models that lack cellular specificity. Methods We used constitutive and neuron-specific gene ablation models targeting an integral subunit of neuronal GIRK channels (GIRK2) to probe the impact of GIRK channels on associative learning and memory. Results Constitutive Girk2−/− mice exhibited a striking deficit in hippocampal-dependent (contextual) and hippocampal-independent (cue) fear conditioning. Mice lacking GIRK2 in GABA neurons (GAD-Cre:Girk2flox/flox mice) exhibited a clear deficit in GIRK-dependent signaling in dorsal hippocampal GABA neurons, but no evident behavioral phenotype. Mice lacking GIRK2 in forebrain pyramidal neurons (CaMKII-Cre(+):Girk2flox/flox mice) exhibited diminished GIRK-dependent signaling in dorsal, but not ventral, hippocampal pyramidal neurons. CaMKII-Cre(+):Girk2flox/flox mice also displayed a selective impairment in contextual fear conditioning, as both cue-fear and spatial learning were intact in these mice. Finally, loss of GIRK2 in forebrain pyramidal neurons correlated with enhanced long-term depression and blunted depotentiation of long-term potentiation at the Schaffer collateral/CA1 synapse in the dorsal hippocampus. Conclusions Our data suggest that GIRK channels in dorsal hippocampal pyramidal neurons are necessary for normal learning involving aversive stimuli, and support the contention that dysregulation of GIRK-dependent signaling may underlie cognitive dysfunction in some disorders. PMID:26612516
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Shp2 in Forebrain Neurons Regulates Synaptic Plasticity, Locomotion, and Memory Formation in Mice
Kusakari, Shinya; Saitow, Fumihito; Ago, Yukio; Shibasaki, Koji; Sato-Hashimoto, Miho; Matsuzaki, Yasunori; Kotani, Takenori; Murata, Yoji; Hirai, Hirokazu; Matsuda, Toshio; Suzuki, Hidenori
2015-01-01
Shp2 (Src homology 2 domain-containing protein tyrosine phosphatase 2) regulates neural cell differentiation. It is also expressed in postmitotic neurons, however, and mutations of Shp2 are associated with clinical syndromes characterized by mental retardation. Here we show that conditional-knockout (cKO) mice lacking Shp2 specifically in postmitotic forebrain neurons manifest abnormal behavior, including hyperactivity. Novelty-induced expression of immediate-early genes and activation of extracellular-signal-regulated kinase (Erk) were attenuated in the cerebral cortex and hippocampus of Shp2 cKO mice, suggestive of reduced neuronal activity. In contrast, ablation of Shp2 enhanced high-K+-induced Erk activation in both cultured cortical neurons and synaptosomes, whereas it inhibited that induced by brain-derived growth factor in cultured neurons. Posttetanic potentiation and paired-pulse facilitation were attenuated and enhanced, respectively, in hippocampal slices from Shp2 cKO mice. The mutant mice also manifested transient impairment of memory formation in the Morris water maze. Our data suggest that Shp2 contributes to regulation of Erk activation and synaptic plasticity in postmitotic forebrain neurons and thereby controls locomotor activity and memory formation. PMID:25713104
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Estradiol selectively enhances auditory function in avian forebrain neurons
Caras, Melissa L.; O’Brien, Matthew; Brenowitz, Eliot A.; Rubel, Edwin W
2012-01-01
Sex steroids modulate vertebrate sensory processing, but the impact of circulating hormone levels on forebrain function remains unclear. We tested the hypothesis that circulating sex steroids modulate single-unit responses in the avian telencephalic auditory nucleus, field L. We mimicked breeding or non-breeding conditions by manipulating plasma 17β-estradiol levels in wild-caught female Gambel’s white-crowned sparrows (Zonotrichia leucophrys gambelii). Extracellular responses of single neurons to tones and conspecific songs presented over a range of intensities revealed that estradiol selectively enhanced auditory function in cells that exhibited monotonic rate-level functions to pure tones. In these cells, estradiol treatment increased spontaneous and maximum evoked firing rates, increased pure tone response strengths and sensitivity, and expanded the range of intensities over which conspecific song stimuli elicited significant responses. Estradiol did not significantly alter the sensitivity or dynamic ranges of cells that exhibited non-monotonic rate-level functions. Notably, there was a robust correlation between plasma estradiol concentrations in individual birds and physiological response properties in monotonic, but not non-monotonic neurons. These findings demonstrate that functionally distinct classes of anatomically overlapping forebrain neurons are differentially regulated by sex steroid hormones in a dose-dependent manner. PMID:23223283
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Wu, Pu; Shen, Qian; Dong, Suzhen; Xu, Zhiliang; Tsien, Joe Z; Hu, Yinghe
2008-10-01
Conditional double knockout of presenilin-1 and presenilin-2 (cDKO) in forebrain of mice led to brain atrophy, tau hyperphosphorylation, synaptic dysfunction and cognitive deficit. These brain changes recapitulated most of the neurodegenerative phenotypes of Alzheimer's disease (AD). In this report, we have investigated the effects of 4-month calorie restriction (CR) regimen on different phenotypes in cDKO mice. We found that CR improved novel object recognition and contextual fear conditioning memory in the cDKO mice. Histological and biochemical analysis showed that CR attenuated ventricle enlargement, caspase-3 activation and astrogliosis. In addition, the induction of tau hyperphosphorylation in the cDKO mice was reduced by CR, possibly through reduction of p25 accumulation and aberrant CDK5 activation. Finally, DNA microarray analysis demonstrated that CR could increase the expression of neurogenesis related genes and decrease the expression of inflammation related genes in the hippocampus of cDKO mice. The possible molecular mechanisms of the CR effects on alleviating AD pathogenesis have been discussed.
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Multiple sites of extinction for a single learned response
Mauk, Michael D.
2012-01-01
Most learned responses can be diminished by extinction, a process that can be engaged when a conditioned stimulus (CS) is presented but not reinforced. We present evidence that plasticity in at least two brain regions can mediate extinction of responses produced by trace eyelid conditioning, where the CS and the reinforcing stimulus are separated by a stimulus-free interval. We observed individual differences in the effects of blocking extinction mechanisms in the cerebellum, the structure that, along with several forebrain structures, mediates acquisition of trace eyelid responses; in some rabbits extinction was prevented, whereas in others it was largely unaffected. We also show that cerebellar mechanisms can mediate extinction when noncerebellar mechanisms are bypassed. Together, these observations indicate that trace eyelid responses can be extinguished via processes operating at more than one site, one in the cerebellum and one upstream in forebrain. The relative contributions of these sites may vary from animal to animal and situation to situation. PMID:21940608
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Mu opioid receptors in GABAergic forebrain neurons moderate motivation for heroin and palatable food
Charbogne, Pauline; Gardon, Olivier; Martín-García, Elena; Keyworth, Helen L.; Matsui, Aya; Mechling, Anna E.; Bienert, Thomas; Nasseef, Taufiq; Robé, Anne; Moquin, Luc; Darcq, Emmanuel; Ben Hamida, Sami; Robledo, Patricia; Matifas, Audrey; Befort, Katia; Gavériaux-Ruff, Claire; Harsan, Laura-Adela; Von Everfeldt, Dominik; Hennig, Jurgen; Gratton, Alain; Kitchen, Ian; Bailey, Alexis; Alvarez, Veronica A.; Maldonado, Rafael; Kieffer, Brigitte L.
2016-01-01
BACKGROUND Mu opioid receptors (MORs) are central to pain control, drug reward and addictive behaviors, but underlying circuit mechanisms have been poorly explored by genetic approaches. Here we investigate the contribution of MORs expressed in GABAergic forebrain neurons to major biological effects of opiates, and also challenge the canonical disinhibition model of opiate reward. METHODS We used Dlx5/6-mediated recombination to create conditional Oprm1 mice in GABAergic forebrain neurons. We characterized the genetic deletion by histology, electrophysiology and microdialysis, probed neuronal activation by c-Fos immunohistochemistry and resting state-functional magnetic resonance imaging, and investigated main behavioral responses to opiates, including motivation to obtain heroin and palatable food. RESULTS Mutant mice showed MOR transcript deletion mainly in the striatum. In the ventral tegmental area (VTA), local MOR activity was intact, and reduced activity was only observed at the level of striatonigral afferents. Heroin-induced neuronal activation was modified at both sites, and whole-brain functional networks were altered in live animals. Morphine analgesia was not altered, neither was physical dependence to chronic morphine. In contrast, locomotor effects of heroin were abolished, and heroin-induced catalepsy was increased. Place preference to heroin was not modified, but remarkably, motivation to obtain heroin and palatable food was enhanced in operant self-administration procedures. CONCLUSIONS Our study reveals dissociable MOR functions across mesocorticolimbic networks. Thus beyond a well-established role in reward processing, operating at the level of local VTA neurons, MORs also moderate motivation for appetitive stimuli within forebrain circuits that drive motivated behaviors. PMID:28185645
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Heiser, Laura M; Berman, Rebecca A; Saunders, Richard C; Colby, Carol L
2005-11-01
With each eye movement, a new image impinges on the retina, yet we do not notice any shift in visual perception. This perceptual stability indicates that the brain must be able to update visual representations to take our eye movements into account. Neurons in the lateral intraparietal area (LIP) update visual representations when the eyes move. The circuitry that supports these updated representations remains unknown, however. In this experiment, we asked whether the forebrain commissures are necessary for updating in area LIP when stimulus representations must be updated from one visual hemifield to the other. We addressed this question by recording from LIP neurons in split-brain monkeys during two conditions: stimulus traces were updated either across or within hemifields. Our expectation was that across-hemifield updating activity in LIP would be reduced or abolished after transection of the forebrain commissures. Our principal finding is that LIP neurons can update stimulus traces from one hemifield to the other even in the absence of the forebrain commissures. This finding provides the first evidence that representations in parietal cortex can be updated without the use of direct cortico-cortical links. The second main finding is that updating activity in LIP is modified in the split-brain monkey: across-hemifield signals are reduced in magnitude and delayed in onset compared with within-hemifield signals, which indicates that the pathways for across-hemifield updating are less effective in the absence of the forebrain commissures. Together these findings reveal a dynamic circuit that contributes to updating spatial representations.
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Snider, Kaitlin H.; Dziema, Heather; Aten, Sydney; Loeser, Jacob; Norona, Frances E.; Hoyt, Kari; Obrietan, Karl
2017-01-01
A large body of literature has shown that the disruption of circadian clock timing has profound effects on mood, memory and complex thinking. Central to this time keeping process is the master circadian pacemaker located within the suprachiasmatic nucleus (SCN). Of note, within the central nervous system, clock timing is not exclusive to the SCN, but rather, ancillary oscillatory capacity has been detected in a wide range of cell types and brain regions, including forebrain circuits that underlie complex cognitive processes. These observations raise questions about the hierarchical and functional relationship between the SCN and forebrain oscillators, and, relatedly, about the underlying clock-gated synaptic circuitry that modulates cognition. Here, we utilized a clock knockout strategy in which the essential circadian timing gene Bmal1 was selectively deleted from excitatory forebrain neurons, whilst the SCN clock remained intact, to test the role of forebrain clock timing in learning, memory, anxiety, and behavioral despair. With this model system, we observed numerous effects on hippocampus-dependent measures of cognition. Mice lacking forebrain Bmal1 exhibited deficits in both acquisition and recall on the Barnes maze. Notably, loss of forebrain Bmal1 abrogated time-of-day dependent novel object location memory. However, the loss of Bmal1 did not alter performance on the elevated plus maze, open field assay, and tail suspension test, indicating that this phenotype specifically impairs cognition but not affect. Together, these data suggest that forebrain clock timing plays a critical role in shaping the efficiency of learning and memory retrieval over the circadian day. PMID:27091299
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Snider, Kaitlin H; Dziema, Heather; Aten, Sydney; Loeser, Jacob; Norona, Frances E; Hoyt, Kari; Obrietan, Karl
2016-07-15
A large body of literature has shown that the disruption of circadian clock timing has profound effects on mood, memory and complex thinking. Central to this time keeping process is the master circadian pacemaker located within the suprachiasmatic nucleus (SCN). Of note, within the central nervous system, clock timing is not exclusive to the SCN, but rather, ancillary oscillatory capacity has been detected in a wide range of cell types and brain regions, including forebrain circuits that underlie complex cognitive processes. These observations raise questions about the hierarchical and functional relationship between the SCN and forebrain oscillators, and, relatedly, about the underlying clock-gated synaptic circuitry that modulates cognition. Here, we utilized a clock knockout strategy in which the essential circadian timing gene Bmal1 was selectively deleted from excitatory forebrain neurons, whilst the SCN clock remained intact, to test the role of forebrain clock timing in learning, memory, anxiety, and behavioral despair. With this model system, we observed numerous effects on hippocampus-dependent measures of cognition. Mice lacking forebrain Bmal1 exhibited deficits in both acquisition and recall on the Barnes maze. Notably, loss of forebrain Bmal1 abrogated time-of-day dependent novel object location memory. However, the loss of Bmal1 did not alter performance on the elevated plus maze, open field assay, and tail suspension test, indicating that this phenotype specifically impairs cognition but not affect. Together, these data suggest that forebrain clock timing plays a critical role in shaping the efficiency of learning and memory retrieval over the circadian day. Copyright © 2016 Elsevier B.V. All rights reserved.
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Genomic Perspectives of Transcriptional Regulation in Forebrain Development
Nord, Alex S.; Pattabiraman, Kartik; Visel, Axel; ...
2015-01-07
The forebrain is the seat of higher-order brain functions, and many human neuropsychiatric disorders are due to genetic defects affecting forebrain development, making it imperative to understand the underlying genetic circuitry. We report that recent progress now makes it possible to begin fully elucidating the genomic regulatory mechanisms that control forebrain gene expression. Here, we discuss the current knowledge of how transcription factors drive gene expression programs through their interactions with cis-acting genomic elements, such as enhancers; how analyses of chromatin and DNA modifications provide insights into gene expression states; and how these approaches yield insights into the evolution ofmore » the human brain.« less
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Switching control of sympathetic activity from forebrain to hindbrain in chronic dehydration
Colombari, Débora S A; Colombari, Eduardo; Freiria-Oliveira, Andre H; Antunes, Vagner R; Yao, Song T; Hindmarch, Charles; Ferguson, Alastair V; Fry, Mark; Murphy, David; Paton, Julian F R
2011-01-01
Abstract We investigated the mechanisms responsible for increased blood pressure and sympathetic nerve activity (SNA) caused by 2–3 days dehydration (DH) both in vivo and in situ preparations. In euhydrated (EH) rats, systemic application of the AT1 receptor antagonist Losartan and subsequent pre-collicular transection (to remove the hypothalamus) significantly reduced thoracic (t)SNA. In contrast, in DH rats, Losartan, followed by pre-collicular and pontine transections, failed to reduce tSNA, whereas transection at the medulla–spinal cord junction massively reduced tSNA. In DH but not EH rats, selective inhibition of the commissural nucleus tractus solitarii (cNTS) significantly reduced tSNA. Comparable data were obtained in both in situ and in vivo (anaesthetized/conscious) rats and suggest that following chronic dehydration, the control of tSNA transfers from supra-brainstem structures (e.g. hypothalamus) to the medulla oblongata, particularly the cNTS. As microarray analysis revealed up-regulation of AP1 transcription factor JunD in the dehydrated cNTS, we tested the hypothesis that AP1 transcription factor activity is responsible for dehydration-induced functional plasticity. When AP1 activity was blocked in the cNTS using a viral vector expressing a dominant negative FosB, cNTS inactivation was ineffective. However, tSNA was decreased after pre-collicular transection, a response similar to that seen in EH rats. Thus, the dehydration-induced switch in control of tSNA from hypothalamus to cNTS seems to be mediated via activation of AP1 transcription factors in the cNTS. If AP1 activity is blocked in the cNTS during dehydration, sympathetic activity control reverts back to forebrain regions. This unique reciprocating neural structure-switching plasticity between brain centres emphasizes the multiple mechanisms available for the adaptive response to dehydration. PMID:21708906
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Steinmetz, Nicholas A.; Moore, Tirin; Knudsen, Eric I.
2017-01-01
Distinct networks in the forebrain and the midbrain coordinate to control spatial attention. The critical involvement of the superior colliculus (SC)—the central structure in the midbrain network—in visuospatial attention has been shown by four seminal, published studies in monkeys (Macaca mulatta) performing multialternative tasks. However, due to the lack of a mechanistic framework for interpreting behavioral data in such tasks, the nature of the SC's contribution to attention remains unclear. Here we present and validate a novel decision framework for analyzing behavioral data in multialternative attention tasks. We apply this framework to re-examine the behavioral evidence from these published studies. Our model is a multidimensional extension to signal detection theory that distinguishes between two major classes of attentional mechanisms: those that alter the quality of sensory information or “sensitivity,” and those that alter the selective gating of sensory information or “choice bias.” Model-based simulations and model-based analyses of data from these published studies revealed a converging pattern of results that indicated that choice-bias changes, rather than sensitivity changes, were the primary outcome of SC manipulation. Our results suggest that the SC contributes to attentional performance predominantly by generating a spatial choice bias for stimuli at a selected location, and that this bias operates downstream of forebrain mechanisms that enhance sensitivity. The findings lead to a testable mechanistic framework of how the midbrain and forebrain networks interact to control spatial attention. SIGNIFICANCE STATEMENT Attention involves the selection of the most relevant information for differential sensory processing and decision making. While the mechanisms by which attention alters sensory encoding (sensitivity control) are well studied, the mechanisms by which attention alters decisional weighting of sensory evidence (choice-bias control) are poorly understood. Here, we introduce a model of multialternative decision making that distinguishes bias from sensitivity effects in attention tasks. With our model, we simulate experimental data from four seminal studies that microstimulated or inactivated a key attention-related midbrain structure, the superior colliculus (SC). We demonstrate that the experimental effects of SC manipulation are entirely consistent with the SC controlling attention by changing choice bias, thereby shedding new light on how the brain mediates attention. PMID:28100734
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Sridharan, Devarajan; Steinmetz, Nicholas A; Moore, Tirin; Knudsen, Eric I
2017-01-18
Distinct networks in the forebrain and the midbrain coordinate to control spatial attention. The critical involvement of the superior colliculus (SC)-the central structure in the midbrain network-in visuospatial attention has been shown by four seminal, published studies in monkeys (Macaca mulatta) performing multialternative tasks. However, due to the lack of a mechanistic framework for interpreting behavioral data in such tasks, the nature of the SC's contribution to attention remains unclear. Here we present and validate a novel decision framework for analyzing behavioral data in multialternative attention tasks. We apply this framework to re-examine the behavioral evidence from these published studies. Our model is a multidimensional extension to signal detection theory that distinguishes between two major classes of attentional mechanisms: those that alter the quality of sensory information or "sensitivity," and those that alter the selective gating of sensory information or "choice bias." Model-based simulations and model-based analyses of data from these published studies revealed a converging pattern of results that indicated that choice-bias changes, rather than sensitivity changes, were the primary outcome of SC manipulation. Our results suggest that the SC contributes to attentional performance predominantly by generating a spatial choice bias for stimuli at a selected location, and that this bias operates downstream of forebrain mechanisms that enhance sensitivity. The findings lead to a testable mechanistic framework of how the midbrain and forebrain networks interact to control spatial attention. Attention involves the selection of the most relevant information for differential sensory processing and decision making. While the mechanisms by which attention alters sensory encoding (sensitivity control) are well studied, the mechanisms by which attention alters decisional weighting of sensory evidence (choice-bias control) are poorly understood. Here, we introduce a model of multialternative decision making that distinguishes bias from sensitivity effects in attention tasks. With our model, we simulate experimental data from four seminal studies that microstimulated or inactivated a key attention-related midbrain structure, the superior colliculus (SC). We demonstrate that the experimental effects of SC manipulation are entirely consistent with the SC controlling attention by changing choice bias, thereby shedding new light on how the brain mediates attention. Copyright © 2017 the authors 0270-6474/17/370480-32$15.00/0.
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Park, Seung Min; Park, Chan Woo; Lee, Tae-Kyeong; Cho, Jeong Hwi; Park, Joon Ha; Lee, Jae-Chul; Chen, Bai Hui; Shin, Bich-Na; Ahn, Ji Hyeon; Tae, Hyun-Jin; Shin, Myoung Cheol; Ohk, Taek Geun; Cho, Jun Hwi; Won, Moo-Ho; Choi, Soo Young; Kim, In Hye
2016-01-01
Ischemic preconditioning (IPC) is a condition of sublethal transient global ischemia and exhibits neuroprotective effects against subsequent lethal ischemic insult. We, in this study, examined the neuroprotective effects of IPC and its effects on immunoreactive changes of antioxidant enzymes including superoxide dismutase (SOD) 1 and SOD2, catalase (CAT) and glutathione peroxidase (GPX) in the gerbil hippocampal CA1 region after transient forebrain ischemia. Pyramidal neurons of the stratum pyramidale (SP) in the hippocampal CA1 region of animals died 5 days after lethal transient ischemia without IPC (8.6% (ratio of remanent neurons) of the sham-operated group); however, IPC prevented the pyramidal neurons from subsequent lethal ischemic injury (92.3% (ratio of remanent neurons) of the sham-operated group). SOD1, SOD2, CAT and GPX immunoreactivities in the sham-operated animals were easily detected in pyramidal neurons in the stratum pyramidale (SP) of the hippocampal CA1 region, while all of these immunoreactivities were rarely detected in the stratum pyramidale at 5 days after lethal transient ischemia without IPC. Meanwhile, their immunoreactivities in the sham-operated animals with IPC were similar to (SOD1, SOD2 and CAT) or higher (GPX) than those in the sham-operated animals without IPC. Furthermore, their immunoreactivities in the stratum pyramidale of the ischemia-operated animals with IPC were steadily maintained after lethal ischemia/reperfusion. Results of western blot analysis for SOD1, SOD2, CAT and GPX were similar to immunohistochemical data. In conclusion, IPC maintained or increased the expression of antioxidant enzymes in the stratum pyramidale of the hippocampal CA1 region after subsequent lethal transient forebrain ischemia and IPC exhibited neuroprotective effects in the hippocampal CA1 region against transient forebrain ischemia. PMID:27630689
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Charbogne, Pauline; Gardon, Olivier; Martín-García, Elena; Keyworth, Helen L; Matsui, Aya; Mechling, Anna E; Bienert, Thomas; Nasseef, Taufiq; Robé, Anne; Moquin, Luc; Darcq, Emmanuel; Ben Hamida, Sami; Robledo, Patricia; Matifas, Audrey; Befort, Katia; Gavériaux-Ruff, Claire; Harsan, Laura-Adela; von Elverfeldt, Dominik; Hennig, Jurgen; Gratton, Alain; Kitchen, Ian; Bailey, Alexis; Alvarez, Veronica A; Maldonado, Rafael; Kieffer, Brigitte L
2017-05-01
Mu opioid receptors (MORs) are central to pain control, drug reward, and addictive behaviors, but underlying circuit mechanisms have been poorly explored by genetic approaches. Here we investigate the contribution of MORs expressed in gamma-aminobutyric acidergic forebrain neurons to major biological effects of opiates, and also challenge the canonical disinhibition model of opiate reward. We used Dlx5/6-mediated recombination to create conditional Oprm1 mice in gamma-aminobutyric acidergic forebrain neurons. We characterized the genetic deletion by histology, electrophysiology, and microdialysis; probed neuronal activation by c-Fos immunohistochemistry and resting-state functional magnetic resonance imaging; and investigated main behavioral responses to opiates, including motivation to obtain heroin and palatable food. Mutant mice showed MOR transcript deletion mainly in the striatum. In the ventral tegmental area, local MOR activity was intact, and reduced activity was only observed at the level of striatonigral afferents. Heroin-induced neuronal activation was modified at both sites, and whole-brain functional networks were altered in live animals. Morphine analgesia was not altered, and neither was physical dependence to chronic morphine. In contrast, locomotor effects of heroin were abolished, and heroin-induced catalepsy was increased. Place preference to heroin was not modified, but remarkably, motivation to obtain heroin and palatable food was enhanced in operant self-administration procedures. Our study reveals dissociable MOR functions across mesocorticolimbic networks. Thus, beyond a well-established role in reward processing, operating at the level of local ventral tegmental area neurons, MORs also moderate motivation for appetitive stimuli within forebrain circuits that drive motivated behaviors. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
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Murillo-Rodriguez, Eric; Blanco-Centurion, Carlos; Sanchez, Cristina; Piomelli, Daniele; Shiromani, Priyattam J
2003-12-15
The principal component of marijuana, delta-9-tetrahydrocannabinol increases sleep in humans. Endogenous cannabinoids, such as N-arachidonoylethanolamine (anandamide), also increase sleep. However, the mechanism by which these molecules promote sleep is not known but might involve a sleep-inducing molecule such as adenosine. Microdialysis samples were collected from the basal forebrain in order to detect levels of adenosine before and after injection of anandamide. Rats were implanted for sleep studies, and a cannula was placed in the basal forebrain to collect microdialysis samples. Samples were analyzed using high-performance liquid chromatography. Basic neuroscience research laboratory. Three-month-old male F344 rats. At the start of the lights-on period, animals received systemic injections of dimethyl sulfoxide (vehicle), anandamide, SR141716A (cannabinoid receptor 1 [CB1] antagonist), or SR141716A and anandamide. One hour after injections, microdialysis samples were collected (5 microL) from the basal forebrain every hour over a 20-minute period for 5 hours. The samples were immediately analyzed via high-performance liquid chromatography for adenosine levels. Sleep was also recorded continuously over the same period. Anandamide increased adenosine levels compared to vehicle controls with the peak levels being reached during the third hour after drug injection. There was a significant increase in slow-wave sleep during the third hour. The induction in sleep and the rise in adenosine were blocked by the CB1-receptor antagonist, SR141716A. Anandamide increased adenosine levels in the basal forebrain and also increased sleep. The soporific effects of anandamide were mediated by the CB1 receptor, since the effects were blocked by the CB1-receptor antagonist. These findings identify a potential therapeutic use of endocannabinoids to induce sleep in conditions where sleep may be severely attenuated.
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Sexual dimorphism in BDNF signaling after neonatal hypoxia-ischemia and treatment with necrostatin-1
Chavez-Valdez, Raul; Martin, Lee J.; Razdan, Sheila; Gauda, Estelle B.; Northington, Frances J.
2014-01-01
Brain injury due to neonatal hypoxia-ischemia (HI) is more homogenously severe in male than in female mice. Because, necrostatin-1 (nec-1) prevents injury progression only in male mice, we hypothesized that changes in BDNF signaling after HI and nec-1 are also sex-specific providing differential conditions to promote recovery of those more severely injured. The increased aromatization of testosterone in male mice during early development and the link between 17-β-estradiol (E2) levels and BDNF transcription substantiate this hypothesis. Hence, we aimed to investigate if sexual differences in BDNF signaling existed in forebrain and diencephalon after HI and HI/ nec-1 and their correlation with estrogen receptors (ER). C57B6 mice (p7) received nec-1(0.1 μL[8μM]) or vehicle (veh) intracerebroventricularly after HI. At 24h after HI, BDNF levels increased in both sexes in forebrain without evidence of TrkB activation. At 96h after HI, BDNF levels in forebrain decreased below those seen in control mice of both sexes. Additionally, only in female mice, truncated TrkB (Tc.TrkB) and p75ntr levels increased in forebrain and diencephalon. In both, forebrain and diencephalon, nec-1 treatment increased BDNF levels and TrkB activation in male mice while, prevented Tc.TrkB and p75ntr increases in female mice. While E2 levels were unchanged by HI or HI/ nec-1 in either sex or treatment, ERα: ERβ ratios were increased in diencephalon of nec-1 treated male mice and directly correlated with BDNF levels. Neonatal HI produces sex-specific signaling changes in the BDNF system, that are differentially modulated by nec-1. The regional differences in BDNF levels may be a consequence of injury severity after HI, but sexual differences in response to nec-1 after HI may represent a differential thalamo-cortical preservation or alternatively off-target regional effect of nec-1. The biological significance of ERα predominance and its correlation with BDNF levels is still unclear. PMID:24361177
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Ferreira, G; Meurisse, M; Tillet, Y; Lévy, F
2001-01-01
The basal forebrain cholinergic system is involved in different forms of memory. To study its role in social memory in sheep, an immunotoxin, ME20.4 immunoglobulin G (IgG)-saporin, was developed that is specific to basal forebrain cholinergic neurons bearing the p75 neurotrophin receptor. The distribution of sheep cholinergic neurons was mapped with an antibody against choline acetyltransferase. To assess the localization of the p75 receptor on basal forebrain cholinergic neurons, the distribution of p75 receptor-immunoreactive neurons with ME20.4 IgG was examined, and a double-labeling study with antibodies against choline acetyltransferase and p75 receptor was undertaken. The loss of basal forebrain cholinergic neurons and acetylcholinesterase fibers in basal forebrain projection areas was assessed in ewes that had received intracerebroventricular injections of the immunotoxin (50, 100 or 150 microg) alone, as well as, in some of the ewes treated with the highest dose, with bilateral immunotoxin injections in the nucleus basalis (11 microg/side). Results indicated that choline acetyltransferase- and p75 receptor-immunoreactive cells had similar distributions in the medial septum, the vertical and horizontal limbs of the band of Broca, and the nucleus basalis. The double-labeling procedure revealed that 100% of the cholinergic neurons are also p75 receptor positive in the medial septum and in the vertical and horizontal limbs of the band of Broca, and 82% in the nucleus basalis. Moreover, 100% of the p75 receptor-immunoreactive cells of these four nuclei were cholinergic. Combined immunotoxin injections into ventricles and the nucleus basalis produced a near complete loss (80-95%) of basal forebrain cholinergic neurons and acetylcholinesterase-positive fibers in the hippocampus, olfactory bulb and entorhinal cortex. This study provides the first anatomical data concerning the basal forebrain cholinergic system in ungulates. The availability of a selective cholinergic immunotoxin effective in sheep provides a new tool to probe the involvement of basal forebrain cholinergic neurons in cognitive processes in this species.
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Shi, Wei; Chen, Xueran; Wang, Fen; Gao, Ming; Yang, Yang; Du, Zhaoxia; Wang, Chen; Yao, Yao; He, Kun; Hao, Aijun
2016-09-01
In vertebrates, neural stem/progenitor cells (NSPCs) maintenance is critical for nervous system development and homeostasis. However, the molecular mechanisms underlying the maintenance of NSPCs have not been fully elucidated. Here, we demonstrated that zebrafish ZDHHC16, a DHHC encoding protein, which was related to protein palmitoylation after translation, was expressed in the developing forebrain, and especially in the telencephalon. Loss- and gain-of-function studies showed that ZDHHC16 played a crucial role in the regualtion of NSPCs proliferation during zebrafish telencephalic development, via a mechanism dependent on its palmitoyltransferase activity. Further analyses showed that the inhibition of ZDHHC16 led to inactivation of the FGF/ERK signaling pathway during telencephalic NSPCs proliferation and maintenance. Taken together, our results suggest that ZDHHC16 activity is essential for early NSPCs proliferation where it acts to activate the FGF/ERK network, allowing for the initiation of proliferation -regulated gene expression programs. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1014-1028, 2016. © 2016 Wiley Periodicals, Inc.
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Oh, J D; Butcher, L L; Woolf, N J
1991-04-24
Hyperthyroidism, induced in rat pups by the daily intraperitoneal administration of 1 microgram/g body weight triiodothyronine, facilitated the development of ChAT fiber plexuses in brain regions innervated by basal forebrain cholinergic neurons, leading to an earlier and increased expression of cholinergic markers in those fibers in the cortex, hippocampus and amygdala. A similar enhancement was seen in the caudate-putamen complex. This histochemical profile was correlated with an accelerated appearance of ChAT-positive telencephalic puncta, as well as with a larger total number of cholinergic terminals expressed, which persisted throughout the eight postnatal week, the longest time examined in the present study. Hypothyroidism was produced in rat pups by adding 0.5% propylthiouracil to the dams' diet beginning the day after birth. This dietary manipulation resulted in the diminished expression of ChAT in forebrain fibers and terminals. Hypothyroid treatment also reduced the quantity of ChAT puncta present during postnatal weeks 2 and 3, and, from week 4 and continuing through week 6, the number of ChAT-positive terminals in the telencephalic regions examined was actually less than the amount extant during the former developmental epoch. Immunostaining for nerve growth factor receptor (NGF-R), which is associated almost exclusively with ChAT-positive somata and fibers in the basal forebrain, demonstrated a different time course of postnatal development. Forebrain fibers and terminals demonstrating NGF-R were maximally visualized 1 week postnatally, a time at which these same neuronal elements evinced minimal ChAT-like immunopositivity. Thereafter and correlated with increased immunoreactivity for ChAT, fine details of NGF-R stained fibers were observed less frequently. Although propylthiouracil administration decreased NGF-R immunodensity, no alteration in the development of that receptor was observed as a function of triiodothyronine treatment. Cholinergic terminals in the ventrobasal thalamus, which derive from ChAT-positive neurons in the pedunculopontine and laterodorsal tegmental nucleus, were unaffected by either hyperthyroid or hypothyroid conditions. These cells also do not demonstrate NGF-R. We conclude from these experiments (1) that cholinergic fiber plexuses eventually exhibiting ChAT positivity in the telencephalon demonstrate NGF-R prior to the cholinergic synthetic enzyme, (2) that susceptibility to thyroid hormone manipulations may involve sensitivity to NGF, at least in some forebrain cholinergic systems and (3) that the effects of thyroid hormone imbalances on brain cholinergic neurons are regionally selective.
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Environment enrichment rescues the neurodegenerative phenotypes in presenilins-deficient mice.
Dong, Suzhen; Li, Chunxia; Wu, Pu; Tsien, Joe Z; Hu, Yinghe
2007-07-01
Presenilin (PS) 1 and 2 conditional double knockout (cDKO) mice show progressive memory dysfunction and forebrain degeneration. Gene expression profiling results revealed a strong activation of immunity and inflammation responses in the brains of 10-month-old cDKO mice. As environmental enrichment (EE) has been shown to be able to improve memory and induce neurogenesis of the brain, we assessed the effects of EE on the memory performance and the neurodegeneration in cDKO mice. We found that EE effectively enhanced memory and partially rescued the forebrain atrophy of the cDKO mice. Our results suggest that immunity and inflammation could play important roles in the neurodegeneration of cDKO mice. Furthermore, the beneficial effects of EE may be associated with the inhibition of the expression of immunity and inflammation-related genes in the brain.
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Lim, Ee Peng; Dawe, Gavin S; Jay, Thérèse M
2017-01-01
Noradrenaline (NA), released by the locus coeruleus (LC), plays a key role in mediating the effects of stress on memory functions. The LC provides diffuse projections to many forebrain nuclei including the hippocampus, the prefrontal cortex (PFC), and the basolateral amygdala (BLA). These three structures are intricately interlinked. The hippocampal-prefrontal (H-PFC) pathway is involved in various cognitive functions. The first aim of this study was to examine the role of BLA in H-PFC plasticity by infusion of drugs to activate and inactivate the BLA and studying the effects on H-PFC long-term potentiation (LTP) in the rat in vivo. Activation of the BLA with glutamate impaired, while inactivation with muscimol augmented, H-PFC LTP. This study also aimed to demonstrate how directly applying noradrenaline and other noradrenergic agents in the BLA can affect H-PFC LTP. Noradrenaline at 1μg/0.2μl enhanced H-PFC LTP. Stimulating alpha-2-adrenoceptors in the BLA with clonidine enhanced LTP while blocking alpha-2 adrenoceptors with idazoxan impaired it. Propranolol, a non-selective beta antagonist, enhanced H-PFC LTP while isoprenaline, a non-selective beta agonist, decreased H-PFC LTP. These results suggest that the BLA regulates H-PFC plasticity negatively and also provide a mechanism by which noradrenaline in the BLA can affect H-PFC plasticity via alpha-2 and beta adrenoceptors. Copyright © 2016 Elsevier Inc. All rights reserved.
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Enzyme reactor design under thermal inactivation.
Illanes, Andrés; Wilson, Lorena
2003-01-01
Temperature is a very relevant variable for any bioprocess. Temperature optimization of bioreactor operation is a key aspect for process economics. This is especially true for enzyme-catalyzed processes, because enzymes are complex, unstable catalysts whose technological potential relies on their operational stability. Enzyme reactor design is presented with a special emphasis on the effect of thermal inactivation. Enzyme thermal inactivation is a very complex process from a mechanistic point of view. However, for the purpose of enzyme reactor design, it has been oversimplified frequently, considering one-stage first-order kinetics of inactivation and data gathered under nonreactive conditions that poorly represent the actual conditions within the reactor. More complex mechanisms are frequent, especially in the case of immobilized enzymes, and most important is the effect of catalytic modulators (substrates and products) on enzyme stability under operation conditions. This review focuses primarily on reactor design and operation under modulated thermal inactivation. It also presents a scheme for bioreactor temperature optimization, based on validated temperature-explicit functions for all the kinetic and inactivation parameters involved. More conventional enzyme reactor design is presented merely as a background for the purpose of highlighting the need for a deeper insight into enzyme inactivation for proper bioreactor design.
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2017-01-01
Abstract While a topographic map of auditory space exists in the vertebrate midbrain, it is absent in the forebrain. Yet, both brain regions are implicated in sound localization. The heterogeneous spatial tuning of adjacent sites in the forebrain compared to the midbrain reflects different underlying circuitries, which is expected to affect the correlation structure, i.e., signal (similarity of tuning) and noise (trial-by-trial variability) correlations. Recent studies have drawn attention to the impact of response correlations on the information readout from a neural population. We thus analyzed the correlation structure in midbrain and forebrain regions of the barn owl’s auditory system. Tetrodes were used to record in the midbrain and two forebrain regions, Field L and the downstream auditory arcopallium (AAr), in anesthetized owls. Nearby neurons in the midbrain showed high signal and noise correlations (RNCs), consistent with shared inputs. As previously reported, Field L was arranged in random clusters of similarly tuned neurons. Interestingly, AAr neurons displayed homogeneous monotonic azimuth tuning, while response variability of nearby neurons was significantly less correlated than the midbrain. Using a decoding approach, we demonstrate that low RNC in AAr restricts the potentially detrimental effect it can have on information, assuming a rate code proposed for mammalian sound localization. This study harnesses the power of correlation structure analysis to investigate the coding of auditory space. Our findings demonstrate distinct correlation structures in the auditory midbrain and forebrain, which would be beneficial for a rate-code framework for sound localization in the nontopographic forebrain representation of auditory space. PMID:28674698
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Chen, Kevin; Cases, Olivier; Rebrin, Igor; Wu, Weihua; Gallaher, Timothy K; Seif, Isabelle; Shih, Jean Chen
2007-01-05
Previous studies have established that abrogation of monoamine oxidase (MAO) A expression leads to a neurochemical, morphological, and behavioral specific phenotype with increased levels of serotonin (5-HT), norepinephrine, and dopamine, loss of barrel field structure in mouse somatosensory cortex, and an association with increased aggression in adults. Forebrain-specific MAO A transgenic mice were generated from MAO A knock-out (KO) mice by using the promoter of calcium-dependent kinase IIalpha (CaMKIIalpha). The presence of human MAO A transgene and its expression were verified by PCR of genomic DNA and reverse transcription-PCR of mRNA and Western blot, respectively. Significant MAO A catalytic activity, autoradiographic labeling of 5-HT, and immunocytochemistry of MAO A were found in the frontal cortex, striatum, and hippocampus but not in the cerebellum of the forebrain transgenic mice. Also, compared with MAO A KO mice, lower levels of 5-HT, norepinephrine, and DA and higher levels of MAO A metabolite 5-hydroxyindoleacetic acid were found in the forebrain regions but not in the cerebellum of the transgenic mice. These results suggest that MAO A is specifically expressed in the forebrain regions of transgenic mice. This forebrain-specific differential expression resulted in abrogation of the aggressive phenotype. Furthermore, the disorganization of the somatosensory cortex barrel field structure associated with MAO A KO mice was restored and became morphologically similar to wild type. Thus, the lack of MAO A in the forebrain of MAO A KO mice may underlie their phenotypes.
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Wang, Tao; Wu, Jinhui; Qi, Jiancheng; Hao, Limei; Yi, Ying; Zhang, Zongxing
2016-05-15
Bacillus subtilis subsp. niger spore and Staphylococcus albus are typical biological indicators for the inactivation of airborne pathogens. The present study characterized and compared the behaviors of B. subtilis subsp. niger spores and S. albus in regard to inactivation by chlorine dioxide (ClO2) gas under different gas concentrations and relative humidity (RH) conditions. The inactivation kinetics under different ClO2 gas concentrations (1 to 5 mg/liter) were determined by first-order and Weibull models. A new model (the Weibull-H model) was established to reveal the inactivation tendency and kinetics for ClO2 gas under different RH conditions (30 to 90%). The results showed that both the gas concentration and RH were significantly (P < 0.05) and positively correlated with the inactivation of the two chosen indicators. There was a rapid improvement in the inactivation efficiency under high RH (>70%). Compared with the first-order model, the Weibull and Weibull-H models demonstrated a better fit for the experimental data, indicating nonlinear inactivation behaviors of the vegetative bacteria and spores following exposure to ClO2 gas. The times to achieve a six-log reduction of B. subtilis subsp. niger spore and S. albus were calculated based on the established models. Clarifying the kinetics of inactivation of B. subtilis subsp. niger spores and S. albus by ClO2 gas will allow the development of ClO2 gas treatments that provide an effective disinfection method. Chlorine dioxide (ClO2) gas is a novel and effective fumigation agent with strong oxidization ability and a broad biocidal spectrum. The antimicrobial efficacy of ClO2 gas has been evaluated in many previous studies. However, there are presently no published models that can be used to describe the kinetics of inactivation of airborne pathogens by ClO2 gas under different gas concentrations and RH conditions. The first-order and Weibull (Weibull-H) models established in this study can characterize and compare the behaviors of Bacillus subtilis subsp. niger spores and Staphylococcus albus in regard to inactivation by ClO2 gas, determine the kinetics of inactivation of two chosen strains under different conditions of gas concentration and RH, and provide the calculated time to achieve a six-log reduction. These results will be useful to determine effective conditions for ClO2 gas to inactivate airborne pathogens in contaminated air and other environments and thus prevent outbreaks of airborne illness. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
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Wang, Tao; Wu, Jinhui; Hao, Limei; Yi, Ying; Zhang, Zongxing
2016-01-01
ABSTRACT Bacillus subtilis subsp. niger spore and Staphylococcus albus are typical biological indicators for the inactivation of airborne pathogens. The present study characterized and compared the behaviors of B. subtilis subsp. niger spores and S. albus in regard to inactivation by chlorine dioxide (ClO2) gas under different gas concentrations and relative humidity (RH) conditions. The inactivation kinetics under different ClO2 gas concentrations (1 to 5 mg/liter) were determined by first-order and Weibull models. A new model (the Weibull-H model) was established to reveal the inactivation tendency and kinetics for ClO2 gas under different RH conditions (30 to 90%). The results showed that both the gas concentration and RH were significantly (P < 0.05) and positively correlated with the inactivation of the two chosen indicators. There was a rapid improvement in the inactivation efficiency under high RH (>70%). Compared with the first-order model, the Weibull and Weibull-H models demonstrated a better fit for the experimental data, indicating nonlinear inactivation behaviors of the vegetative bacteria and spores following exposure to ClO2 gas. The times to achieve a six-log reduction of B. subtilis subsp. niger spore and S. albus were calculated based on the established models. Clarifying the kinetics of inactivation of B. subtilis subsp. niger spores and S. albus by ClO2 gas will allow the development of ClO2 gas treatments that provide an effective disinfection method. IMPORTANCE Chlorine dioxide (ClO2) gas is a novel and effective fumigation agent with strong oxidization ability and a broad biocidal spectrum. The antimicrobial efficacy of ClO2 gas has been evaluated in many previous studies. However, there are presently no published models that can be used to describe the kinetics of inactivation of airborne pathogens by ClO2 gas under different gas concentrations and RH conditions. The first-order and Weibull (Weibull-H) models established in this study can characterize and compare the behaviors of Bacillus subtilis subsp. niger spores and Staphylococcus albus in regard to inactivation by ClO2 gas, determine the kinetics of inactivation of two chosen strains under different conditions of gas concentration and RH, and provide the calculated time to achieve a six-log reduction. These results will be useful to determine effective conditions for ClO2 gas to inactivate airborne pathogens in contaminated air and other environments and thus prevent outbreaks of airborne illness. PMID:26969707
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Embryonic ablation of neuronal VGF increases energy expenditure and reduces body weight.
Jiang, Cheng; Lin, Wei-Jye; Sadahiro, Masato; Shin, Andrew C; Buettner, Christoph; Salton, Stephen R
2017-08-01
Germline ablation of VGF, a secreted neuronal, neuroendocrine, and endocrine peptide precursor, results in lean, hypermetabolic, and infertile adult mice that are resistant to diet-, lesion-, and genetically-induced obesity and diabetes (Hahm et al., 1999, 2002). To assess whether this phenotype is predominantly driven by reduced VGF expression in developing and/or adult neurons, or in peripheral endocrine and neuroendocrine tissues, we generated and analyzed conditional VGF knockout mice, obtained by mating loxP-flanked (floxed) Vgf mice with either pan-neuronal Synapsin-Cre- or forebrain alpha-CaMKII-Cre-recombinase-expressing transgenic mice. Adult male and female mice, with conditional ablation of the Vgf gene in embryonic neurons had significantly reduced body weight, increased energy expenditure, and were resistant to diet-induced obesity. Conditional forebrain postnatal ablation of VGF in male mice, primarily in adult excitatory neurons, had no measurable effect on body weight nor on energy expenditure, but led to a modest increase in adiposity, partially overlapping the effect of AAV-Cre-mediated targeted ablation of VGF in the adult ventromedial hypothalamus and arcuate nucleus of floxed Vgf mice (Foglesong et al., 2016), and also consistent with results of icv delivery of the VGF-derived peptide TLQP-21 to adult mice, which resulted in increased energy expenditure and reduced adiposity (Bartolomucci et al., 2006). Because the lean, hypermetabolic phenotype of germline VGF knockout mice is to a great extent recapitulated in Syn-Cre +/- ,Vgf flpflox/flpflox mice, we conclude that the metabolic profile of germline VGF knockout mice is largely the result of VGF ablation in embryonic CNS neurons, rather than peripheral endocrine and/or neuroendocrine cells, and that in forebrain structures such as hypothalamus, VGF and/or VGF-derived peptides play uniquely different roles in the developing and adult nervous system. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Muller, Christopher L; Anacker, Allison MJ; Rogers, Tiffany D; Goeden, Nick; Keller, Elizabeth H; Forsberg, C Gunnar; Kerr, Travis M; Wender, Carly LA; Anderson, George M; Stanwood, Gregg D; Blakely, Randy D; Bonnin, Alexandre; Veenstra-VanderWeele, Jeremy
2017-01-01
Biomarker, neuroimaging, and genetic findings implicate the serotonin transporter (SERT) in autism spectrum disorder (ASD). Previously, we found that adult male mice expressing the autism-associated SERT Ala56 variant have altered central serotonin (5-HT) system function, as well as elevated peripheral blood 5-HT levels. Early in gestation, before midbrain 5-HT projections have reached the cortex, peripheral sources supply 5-HT to the forebrain, suggesting that altered maternal or placenta 5-HT system function could impact the developing embryo. We therefore used different combinations of maternal and embryo SERT Ala56 genotypes to examine effects on blood, placenta and embryo serotonin levels and neurodevelopment at embryonic day E14.5, when peripheral sources of 5-HT predominate, and E18.5, when midbrain 5-HT projections have reached the forebrain. Maternal SERT Ala56 genotype was associated with decreased placenta and embryonic forebrain 5-HT levels at E14.5. Low 5-HT in the placenta persisted, but forebrain levels normalized by E18.5. Maternal SERT Ala56 genotype effects on forebrain 5-HT levels were accompanied by a broadening of 5-HT-sensitive thalamocortical axon projections. In contrast, no effect of embryo genotype was seen in concepti from heterozygous dams. Blood 5-HT levels were dynamic across pregnancy and were increased in SERT Ala56 dams at E14.5. Placenta RNA sequencing data at E14.5 indicated substantial impact of maternal SERT Ala56 genotype, with alterations in immune and metabolic-related pathways. Collectively, these findings indicate that maternal SERT function impacts offspring placental 5-HT levels, forebrain 5-HT levels, and neurodevelopment. PMID:27550733
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Placenta-derived hypo-serotonin situations in the developing forebrain cause autism.
Sato, Kohji
2013-04-01
Autism is a pervasive developmental disorder that is characterized by the behavioral traits of impaired social cognition and communication, and repetitive and/or obsessive behavior and interests. Although there are many theories and speculations about the pathogenetic causes of autism, the disruption of the serotonergic system is one of the most consistent and well-replicated findings. Recently, it has been reported that placenta-derived serotonin is the main source in embryonic day (E) 10-15 mouse forebrain, after that period, the serotonergic fibers start to supply serotonin into the forebrain. E 10-15 is the very important developing period, when cortical neurogenesis, migration and initial axon targeting are processed. Since all these events have been considered to be involved in the pathogenesis of autism and they are highly controlled by serotonin signals, the paucity of placenta-derived serotonin should have potential importance when the pathogenesis of autism is considered. I, thus, postulate a hypothesis that placenta-derived hypo-serotonin situations in the developing forebrain cause autism. The hypothesis is as follows. Various factors, such as inflammation, dysfunction of the placenta, together with genetic predispositions cause a decrease of placenta-derived serotonin levels. The decrease of placenta-derived serotonin levels leads to hypo-serotonergic situations in the forebrain of the fetus. The paucity of serotonin in the forebrain leads to mis-wiring in important regions which are responsible for the theory of mind. The paucity of serotonin in the forebrain also causes over-growth of serotonergic fibers. These disturbances result in network deficiency and aberration of the serotonergic system, leading to the autistic phenotypes. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Zhang, Chi; Kang, Yi; Lundy, Robert F.
2010-01-01
The pontine parabrachial nucleus (PBN) and medullary reticular formation (RF) are hindbrain regions that, respectively, process sensory input and coordinate motor output related to ingestive behavior. Neural processing in each hindbrain site is subject to modulation originating from several forebrain structures including the insular gustatory cortex (IC), bed nucleus of the stria terminalis (BNST), central nucleus of the amygdala (CeA), and lateral hypothalamus (LH). The present study combined electrophysiology and retrograde tracing techniques to determine the extent of overlap between neurons within the IC, BNST, CeA and LH that target both the PBN and RF. One fluorescent retrograde tracer, red (RFB) or green (GFB) latex microbeads, was injected into the gustatory PBN under electrophysiological guidance and a different retrograde tracer, GFB or fluorogold (FG), into the ipsilateral RF using the location of gustatory NST as a point of reference. Brain tissue containing each forebrain region was sectioned, scanned using a confocal microscope, and scored for the number of single and double labeled neurons. Neurons innervating the RF only, the PBN only, or both the medullary RF and PBN were observed, largely intermingled, in each forebrain region. The CeA contained the largest number of cells retrogradely labeled after tracer injection into either hindbrain region. For each forebrain area except the IC, the origin of descending input to the RF and PBN was almost entirely ipsilateral. Axons from a small percentage of hindbrain projecting forebrain neurons targeted both the PBN and RF. Target specific and non specific inputs from a variety of forebrain nuclei to the hindbrain likely reflect functional specialization in the control of ingestive behaviors. PMID:21040715
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Suda, Yoko; Kokura, Kenji; Kimura, Jun; Kajikawa, Eriko; Inoue, Fumitaka; Aizawa, Shinichi
2010-09-01
We have analyzed Emx2 enhancers to determine how Emx2 functions during forebrain development are regulated. The FB (forebrain) enhancer we identified immediately 3' downstream of the last coding exon is well conserved among tetrapods and unexpectedly directed all the Emx2 expression in forebrain: caudal forebrain primordium at E8.5, dorsal telencephalon at E9.5-E10.5 and the cortical ventricular zone after E12.5. Otx, Tcf, Smad and two unknown transcription factor binding sites were essential to all these activities. The mutant that lacked this enhancer demonstrated that Emx2 expression under the enhancer is solely responsible for diencephalon development. However, in telencephalon, the FB enhancer did not have activities in cortical hem or Cajal-Retzius cells, nor was its activity in the cortex graded. Emx2 expression was greatly reduced, but persisted in the telencephalon of the enhancer mutant, indicating that there exists another enhancer for Emx2 expression unique to mammalian telencephalon.
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Congenital disorder of true cyclopia with polydactylia: case report and review of the literature.
Deftereou, T E; Tsoulopoulos, V; Alexiadis, G; Papadopoulos, E; Chouridou, E; Katotomichelakis, M; Lambropoulou, M
2013-01-01
Cyclopia is a rare type of holoprosencephaly and a congenital disorder characterized by the failure of the embryonic forebrain to properly divide the orbits of the eye into two cavities (the embryonic forebrain is normally responsible for inducing the development of the orbits). As a result a birth defect in which there is only one eye is developed. This eye is centrally placed in the area normally occupied by the root of the nose. As a rule, there is a missing nose or a non-functioning nose in the form of a proboscis (a tubular appendage) located above the central eye. In this report the macroscopic, radiographic, and immunohistochemical findings of a case of true cyclopia in a female fetus are described. Cyclopia is a lethal condition that is associated with dramatic symmetric deformities of the nose, skull, orbits, and brain.
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Mapping pathological phenotypes in a mouse model of CDKL5 disorder.
Amendola, Elena; Zhan, Yang; Mattucci, Camilla; Castroflorio, Enrico; Calcagno, Eleonora; Fuchs, Claudia; Lonetti, Giuseppina; Silingardi, Davide; Vyssotski, Alexei L; Farley, Dominika; Ciani, Elisabetta; Pizzorusso, Tommaso; Giustetto, Maurizio; Gross, Cornelius T
2014-01-01
Mutations in cyclin-dependent kinase-like 5 (CDKL5) cause early-onset epileptic encephalopathy, a neurodevelopmental disorder with similarities to Rett Syndrome. Here we describe the physiological, molecular, and behavioral phenotyping of a Cdkl5 conditional knockout mouse model of CDKL5 disorder. Behavioral analysis of constitutive Cdkl5 knockout mice revealed key features of the human disorder, including limb clasping, hypoactivity, and abnormal eye tracking. Anatomical, physiological, and molecular analysis of the knockout uncovered potential pathological substrates of the disorder, including reduced dendritic arborization of cortical neurons, abnormal electroencephalograph (EEG) responses to convulsant treatment, decreased visual evoked responses (VEPs), and alterations in the Akt/rpS6 signaling pathway. Selective knockout of Cdkl5 in excitatory and inhibitory forebrain neurons allowed us to map the behavioral features of the disorder to separable cell-types. These findings identify physiological and molecular deficits in specific forebrain neuron populations as possible pathological substrates in CDKL5 disorder.
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Medial Auditory Thalamus Inactivation Prevents Acquisition and Retention of Eyeblink Conditioning
ERIC Educational Resources Information Center
Halverson, Hunter E.; Poremba, Amy; Freeman, John H.
2008-01-01
The auditory conditioned stimulus (CS) pathway that is necessary for delay eyeblink conditioning was investigated using reversible inactivation of the medial auditory thalamic nuclei (MATN) consisting of the medial division of the medial geniculate (MGm), suprageniculate (SG), and posterior intralaminar nucleus (PIN). Rats were given saline or…
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1993-05-28
1993 Dissertation and Abstract Approved: Commit tee Chairperson . ,a..w ember ~tee Member tli:u., ;2 9" PQ3 bate Date bate The author...1982; Mesulam et al., 1983; Rye et al., 1984; Saper, 1984). I will refer to the region of the basal forebrain that supplies cholinergic innervation to...topographical organization has been observed for cholinergic projection patterns, with more rostral and medial basal forebrain cell groups supplying
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Effective Thermal Inactivation of the Spores of Bacillus cereus Biofilms Using Microwave.
Park, Hyong Seok; Yang, Jungwoo; Choi, Hee Jung; Kim, Kyoung Heon
2017-07-28
Microwave sterilization was performed to inactivate the spores of biofilms of Bacillus cereus involved in foodborne illness. The sterilization conditions, such as the amount of water and the operating temperature and treatment time, were optimized using statistical analysis based on 15 runs of experimental results designed by the Box-Behnken method. Statistical analysis showed that the optimal conditions for the inactivation of B. cereus biofilms were 14 ml of water, 108°C of temperature, and 15 min of treatment time. Interestingly, response surface plots showed that the amount of water is the most important factor for microwave sterilization under the present conditions. Complete inactivation by microwaves was achieved in 5 min, and the inactivation efficiency by microwave was obviously higher than that by conventional steam autoclave. Finally, confocal laser scanning microscopy images showed that the principal effect of microwave treatment was cell membrane disruption. Thus, this study can contribute to the development of a process to control food-associated pathogens.
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Glycinergic Input to the Mouse Basal Forebrain Cholinergic Neurons
Bardóczi, Zsuzsanna; Pál, Balázs; Kőszeghy, Áron; Wilheim, Tamás; Záborszky, László; Liposits, Zsolt
2017-01-01
The basal forebrain (BF) receives afferents from brainstem ascending pathways, which has been implicated first by Moruzzi and Magoun (1949) to induce forebrain activation and cortical arousal/waking behavior; however, it is very little known about how brainstem inhibitory inputs affect cholinergic functions. In the current study, glycine, a major inhibitory neurotransmitter of brainstem neurons, and gliotransmitter of local glial cells, was tested for potential interaction with BF cholinergic (BFC) neurons in male mice. In the BF, glycine receptor α subunit-immunoreactive (IR) sites were localized in choline acetyltransferase (ChAT)-IR neurons. The effect of glycine on BFC neurons was demonstrated by bicuculline-resistant, strychnine-sensitive spontaneous IPSCs (sIPSCs; 0.81 ± 0.25 × 10−1 Hz) recorded in whole-cell conditions. Potential neuronal as well as glial sources of glycine were indicated in the extracellular space of cholinergic neurons by glycine transporter type 1 (GLYT1)- and GLYT2-IR processes found in apposition to ChAT-IR cells. Ultrastructural analyses identified synapses of GLYT2-positive axon terminals on ChAT-IR neurons, as well as GLYT1-positive astroglial processes, which were localized in the vicinity of synapses of ChAT-IR neurons. The brainstem raphe magnus was determined to be a major source of glycinergic axons traced retrogradely from the BF. Our results indicate a direct effect of glycine on BFC neurons. Furthermore, the presence of high levels of plasma membrane glycine transporters in the vicinity of cholinergic neurons suggests a tight control of extracellular glycine in the BF. SIGNIFICANCE STATEMENT Basal forebrain cholinergic (BFC) neurons receive various activating inputs from specific brainstem areas and channel this information to the cortex via multiple projections. So far, very little is known about inhibitory brainstem afferents to the BF. The current study established glycine as a major regulator of BFC neurons by (1) identifying glycinergic neurons in the brainstem projecting to the BF, (2) showing glycine receptor α subunit-immunoreactive (IR) sites in choline acetyltransferase (ChAT)-IR neurons, (3) demonstrating glycine transporter type 2 (GLYT2)-positive axon terminals synapsing on ChAT-IR neurons, and (4) localizing GLYT1-positive astroglial processes in the vicinity of synapses of ChAT-IR neurons. The effect of glycine on BFC neurons was demonstrated by bicuculline-resistant, strychnine-sensitive spontaneous IPSCs recorded in whole-cell conditions. PMID:28874448
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Rijal, G K; Fujioka, R S
2003-01-01
Aluminum reflectors were added to solar units designed to inactivate faecal microorganisms (faecal coliform, E. coli, enterococci, FRNA coliphage, C. perfringens) in stream water and diluted sewage by the two mechanisms (solar heat, solar UV) known to inactivate microorganisms. During sunny conditions, solar units with and without reflectors inactivated E. coli to <1 CFU/100 ml to meet drinking water standards. Solar units with reflectors disinfected the water sooner by increasing the water temperature by 8-10 degrees C to 64-75 degrees C. However, FRNA coliphages were still detected in these samples, indicating that this treatment may not inactivate pathogenic human enteric viruses. During cloudy conditions, reflectors only increased the water temperature by 3-4 degrees C to a maximum of 43-49 degrees C and E. coli was not completely inactivated. Under sunny and cloudy conditions, the UV wavelengths of sunlight worked synergistically with increasing water temperatures and were able to disinfect microorganisms at temperatures (45-56 degrees C), which were not effective in inactivating microorganisms. Relative resistance to the solar disinfecting effects were C. perfringens > FRNA coliphages > enterococci > E. coli > faecal coliform.
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Double Dissociation of Amygdala and Hippocampal Contributions to Trace and Delay Fear Conditioning
Raybuck, Jonathan D.; Lattal, K. Matthew
2011-01-01
A key finding in studies of the neurobiology of learning memory is that the amygdala is critically involved in Pavlovian fear conditioning. This is well established in delay-cued and contextual fear conditioning; however, surprisingly little is known of the role of the amygdala in trace conditioning. Trace fear conditioning, in which the CS and US are separated in time by a trace interval, requires the hippocampus and prefrontal cortex. It is possible that recruitment of cortical structures by trace conditioning alters the role of the amygdala compared to delay fear conditioning, where the CS and US overlap. To investigate this, we inactivated the amygdala of male C57BL/6 mice with GABA A agonist muscimol prior to 2-pairing trace or delay fear conditioning. Amygdala inactivation produced deficits in contextual and delay conditioning, but had no effect on trace conditioning. As controls, we demonstrate that dorsal hippocampal inactivation produced deficits in trace and contextual, but not delay fear conditioning. Further, pre- and post-training amygdala inactivation disrupted the contextual but the not cued component of trace conditioning, as did muscimol infusion prior to 1- or 4-pairing trace conditioning. These findings demonstrate that insertion of a temporal gap between the CS and US can generate amygdala-independent fear conditioning. We discuss the implications of this surprising finding for current models of the neural circuitry involved in fear conditioning. PMID:21283812
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Mendoza, J; Sanio, C; Chaudhri, N
2015-02-01
The infralimbic medial prefrontal cortex (IL) has been posited as a common node in distinct neural circuits that mediate the extinction of appetitive and aversive conditioning. However, appetitive extinction is typically assessed using instrumental conditioning procedures, whereas the extinction of aversive conditioning is customarily studied using Pavlovian assays. The role of the IL in the extinction of appetitive Pavlovian conditioning remains underexplored. We investigated the involvement of the IL and prelimbic medial prefrontal cortex (PrL) in appetitive extinction in Pavlovian and instrumental conditioning assays in male, Long-Evans rats. Following acquisition, a gamma-aminobutyric acid agonist solution (0.03 nmol muscimol; 0.3 nmol baclofen; 0.3 μl/side) was bilaterally microinfused into the IL or PrL to pharmacologically inactivate each region before the first extinction session. Compared to saline, PrL inactivation did not affect the acquisition of extinction or the recall of extinction memory 24-h later. IL inactivation caused a more rapid extinction of Pavlovian conditioning, but had no effect on the extinction of instrumental conditioning or extinction recall. IL inactivation during a Pavlovian conditioning session in which conditioned stimulus (CS) trials were paired with sucrose did not affect CS-elicited behaviour, but increased responding during intervals that did not contain the CS. The same manipulation did not impact lever pressing for sucrose. These findings suggest that the IL may normally maintain Pavlovian conditioned responding when an anticipated appetitive CS is unexpectedly withheld, and that this region has distinct roles in the expression of Pavlovian conditioning when an appetitive unconditioned stimulus is either presented or omitted. Copyright © 2014 Elsevier Inc. All rights reserved.
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NASA Astrophysics Data System (ADS)
Mayotte, Jean-Marc; Grabs, Thomas; Sutliff-Johansson, Stacy; Bishop, Kevin
2017-06-01
This study examined how the inactivation of bacteriophage MS2 in water was affected by ionic strength (IS) and dissolved organic carbon (DOC) using static batch inactivation experiments at 4 °C conducted over a period of 2 months. Experimental conditions were characteristic of an operational managed aquifer recharge (MAR) scheme in Uppsala, Sweden. Experimental data were fit with constant and time-dependent inactivation models using two methods: (1) traditional linear and nonlinear least-squares techniques; and (2) a Monte-Carlo based parameter estimation technique called generalized likelihood uncertainty estimation (GLUE). The least-squares and GLUE methodologies gave very similar estimates of the model parameters and their uncertainty. This demonstrates that GLUE can be used as a viable alternative to traditional least-squares parameter estimation techniques for fitting of virus inactivation models. Results showed a slight increase in constant inactivation rates following an increase in the DOC concentrations, suggesting that the presence of organic carbon enhanced the inactivation of MS2. The experiment with a high IS and a low DOC was the only experiment which showed that MS2 inactivation may have been time-dependent. However, results from the GLUE methodology indicated that models of constant inactivation were able to describe all of the experiments. This suggested that inactivation time-series longer than 2 months were needed in order to provide concrete conclusions regarding the time-dependency of MS2 inactivation at 4 °C under these experimental conditions.
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Decreased levels of free D-aspartic acid in the forebrain of serine racemase (Srr) knock-out mice.
Horio, Mao; Ishima, Tamaki; Fujita, Yuko; Inoue, Ran; Mori, Hisashi; Hashimoto, Kenji
2013-05-01
d-Serine, an endogenous co-agonist of the N-methyl-d-aspartate (NMDA) receptor is synthesized from l-serine by serine racemase (SRR). A previous study of Srr knockout (Srr-KO) mice showed that levels of d-serine in forebrain regions, such as frontal cortex, hippocampus, and striatum, but not cerebellum, of mutant mice are significantly lower than those of wild-type (WT) mice, suggesting that SRR is responsible for d-serine production in the forebrain. In this study, we attempted to determine whether SRR affects the level of other amino acids in brain tissue. We found that tissue levels of d-aspartic acid in the forebrains (frontal cortex, hippocampus and striatum) of Srr-KO mice were significantly lower than in WT mice, whereas levels of d-aspartic acid in the cerebellum were not altered. Levels of d-alanine, l-alanine, l-aspartic acid, taurine, asparagine, arginine, threonine, γ-amino butyric acid (GABA) and methionine, remained the same in frontal cortex, hippocampus, striatum and cerebellum of WT and mutant mice. Furthermore, no differences in d-aspartate oxidase (DDO) activity were detected in the forebrains of WT and Srr-KO mice. These results suggest that SRR and/or d-serine may be involved in the production of d-aspartic acid in mouse forebrains, although further detailed studies will be necessary to confirm this finding. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Pombal, M A; Puelles, L
1999-11-22
The structural organization of the lamprey extratelencephalic forebrain is re-examined from the perspective of the prosomeric segmental paradigm. The question asked was whether the prosomeric forebrain model used for gnathostomes is of material advantage for interpreting subdivisions in the lamprey forebrain. To this aim, the main longitudinal and transverse landmarks recognized by the prosomeric model in other vertebrates were identified in Nissl-stained lamprey material. Lines of cytoarchitectural discontinuity and contours of migrated neuronal groups were mapped in a two-dimensional sagittal representation and were also classified according to their radial position. Immunocytochemical mapping of calretinin expression in adjacent sections served to define particular structural units better, in particular, the dorsal thalamus. These data were complemented by numerous other chemoarchitectonic observations obtained with ancillary markers, which identified additional specific formations, subdivisions, or boundaries. Emphasis was placed on studying whether such chemically defined neuronal groups showed boundaries aligned with the postulated inter- or intraprosomeric boundaries. The course of diverse axonal tracts was studied also with regard to their prosomeric topography. This analysis showed that the full prosomeric model applies straightforwardly to the lamprey forebrain. This finding implies that a common segmental and longitudinal organization of the neural tube may be primitive for all vertebrates. Interesting novel aspects appear in the interpretation of the lamprey pretectum, the dorsal and ventral thalami, and the hypothalamus. The topologic continuity of the prosomeric forebrain regions with evaginated or non-evaginated portions of the telencephalon was also examined. Copyright 1999 Wiley-Liss, Inc.
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Mechanisms of poliovirus inactivation by the direct and indirect effects of ionizing radiation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ward, R.L.
1980-08-01
This study was designed to measure the effects of ionizing radiation on poliovirus particles when given under conditions where either direct (in broth) or indirect (in water) effects were predominant. Under direct conditions, inactivation of poliovirus was found to be due primarily to RNA damage, although capsid damage could account for about one-third of the viral inactivation. RNA damage did not appear to be due to strand breakage and therefore was probably caused primarily by base damage or crosslink formation. Capsid damage under direct irradiation conditions did not result in significant alterations of either the sedimentation coefficients or the isoelectricmore » points of the poliovirus particles or detectable modification of the sizes of the viral proteins. It did, however, cause loss of availability to bind to host cells. Under indirect conditions no more than 25% of viral inactivation appeared to be due to RNA damage. However, the sedimentation coefficients and isoelectric points of the viral particles were greatly altered, and their abilities to bind to cells were lost at about three-fourths the rate of loss of infectivity. Capsid damage in this case did result in changes in the sizes of capsid proteins. Therefore, the majority of the radiation inactivation under indirect conditions appeared to be due to protein damage.« less
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Microbial Inactivation by Ultrasound Assisted Supercritical Fluids
NASA Astrophysics Data System (ADS)
Benedito, Jose; Ortuño, Carmen; Castillo-Zamudio, Rosa Isela; Mulet, Antonio
A method combining supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) has been developed and tested for microbial/enzyme inactivation purposes, at different process conditions for both liquid and solid matrices. In culture media, using only SC-CO2, the inactivation rate of E. coli and S. cerevisiae increased with pressure and temperature; and the total inactivation (7-8 log-cycles) was attained after 25 and 140 min of SC-CO2 (350 bar, 36 °C) treatment, respectively. Using SC-CO2+HPU, the time for the total inactivation of both microorganisms was reduced to only 1-2 min, at any condition selected. The SC-CO2+HPU inactivation of both microorganisms was slower in juices (avg. 4.9 min) than in culture media (avg. 1.5 min). In solid samples (chicken, turkey ham and dry-cured pork cured ham) treated with SC-CO2 and SC-CO2+HPU, the inactivation rate of E. coli increased with temperature. The application of HPU to the SC-CO2 treatments accelerated the inactivation rate of E. coli and that effect was more pronounced in treatments with isotonic solution surrounding the solid food samples. The application of HPU enhanced the SC-CO2 inactivation mechanisms of microorganisms, generating a vigorous agitation that facilitated the CO2 solubilization and the mass transfer process. The cavitation generated by HPU could damage the cell walls accelerating the extraction of vital constituents and the microbial death. Thus, using the combined technique, reasonable industrial processing times and mild process conditions could be used which could result into a cost reduction and lead to the minimization in the food nutritional and organoleptic changes.
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Differential functions of NR2A and NR2B in short-term and long-term memory in rats.
Jung, Ye-Ha; Suh, Yoo-Hun
2010-08-23
N-methyl-D-aspartate receptors (NMDARs) are glutamate receptors implicated in synaptic plasticity and memory function. The specific functions of NMDA receptor subunits NR2A and NR2B have not yet been fully determined in the different types of memory. Nine Wistar rats (8-weeks-old) were subjected to the Morris water maze task to evaluate the memory behaviorally. Quantitative analysis of NR1, NR2A, and NR2B levels in the right and left forebrain of rats was performed and subunit associations with different types of memory were investigated using the Morris water maze task. Right forebrain NR2A expression was significantly increased and correlated with faster escape time onto a hidden platform, indicating involvement of short-term memory, because of the training time interval. Right forebrain NR2B expression was positively associated with long-term memory lasting 24-h (h). In the left forebrain, NR2B expression was positively related to 72-h long-term memory. In conclusion, the functions of NR2A and NR2B receptors were differentially specialized in short-term and long-term memory, depending on the right or left forebrain.
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Task-phase-specific dynamics of basal forebrain neuronal ensembles
Tingley, David; Alexander, Andrew S.; Kolbu, Sean; de Sa, Virginia R.; Chiba, Andrea A.; Nitz, Douglas A.
2014-01-01
Cortically projecting basal forebrain neurons play a critical role in learning and attention, and their degeneration accompanies age-related impairments in cognition. Despite the impressive anatomical and cell-type complexity of this system, currently available data suggest that basal forebrain neurons lack complexity in their response fields, with activity primarily reflecting only macro-level brain states such as sleep and wake, onset of relevant stimuli and/or reward obtainment. The current study examined the spiking activity of basal forebrain neuron populations across multiple phases of a selective attention task, addressing, in particular, the issue of complexity in ensemble firing patterns across time. Clustering techniques applied to the full population revealed a large number of distinct categories of task-phase-specific activity patterns. Unique population firing-rate vectors defined each task phase and most categories of task-phase-specific firing had counterparts with opposing firing patterns. An analogous set of task-phase-specific firing patterns was also observed in a population of posterior parietal cortex neurons. Thus, consistent with the known anatomical complexity, basal forebrain population dynamics are capable of differentially modulating their cortical targets according to the unique sets of environmental stimuli, motor requirements, and cognitive processes associated with different task phases. PMID:25309352
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Jeong, Da Un; Oh, Jin Hwan; Lee, Ji Eun; Lee, Jihyeon; Cho, Zang Hee; Chang, Jin Woo; Chang, Won Seok
2016-01-01
Reduced brain glucose metabolism and basal forebrain cholinergic neuron degeneration are common features of Alzheimer's disease and have been correlated with memory function. Although regions representing glucose hypometabolism in patients with Alzheimer's disease are targets of cholinergic basal forebrain neurons, the interaction between cholinergic denervation and glucose hypometabolism is still unclear. The aim of the present study was to evaluate glucose metabolism changes caused by cholinergic deficits. We lesioned basal forebrain cholinergic neurons in rats using 192 immunoglobulin G-saporin. After 3 weeks, lesioned animals underwent water maze testing or were analyzed by ¹⁸F-2-fluoro-2-deoxyglucose positron emission tomography. During water maze probe testing, performance of the lesioned group decreased with respect to time spent in the target quadrant and platform zone. Cingulate cortex glucose metabolism in the lesioned group decreased, compared with the normal group. Additionally, acetylcholinesterase activity and glutamate decarboxylase 65/67 expression declined in the cingulate cortex. Our results reveal that spatial memory impairment in animals with selective basal forebrain cholinergic neuron damage is associated with a functional decline in the GABAergic and cholinergic system associated with cingulate cortex glucose hypometabolism.
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Cavodeassi, Florencia; Ivanovitch, Kenzo; Wilson, Stephen W.
2013-01-01
During forebrain morphogenesis, there is extensive reorganisation of the cells destined to form the eyes, telencephalon and diencephalon. Little is known about the molecular mechanisms that regulate region-specific behaviours and that maintain the coherence of cell populations undergoing specific morphogenetic processes. In this study, we show that the activity of the Eph/Ephrin signalling pathway maintains segregation between the prospective eyes and adjacent regions of the anterior neural plate during the early stages of forebrain morphogenesis in zebrafish. Several Ephrins and Ephs are expressed in complementary domains in the prospective forebrain and combinatorial abrogation of their activity results in incomplete segregation of the eyes and telencephalon and in defective evagination of the optic vesicles. Conversely, expression of exogenous Ephs or Ephrins in regions of the prospective forebrain where they are not usually expressed changes the adhesion properties of the cells, resulting in segregation to the wrong domain without changing their regional fate. The failure of eye morphogenesis in rx3 mutants is accompanied by a loss of complementary expression of Ephs and Ephrins, suggesting that this pathway is activated downstream of the regional fate specification machinery to establish boundaries between domains undergoing different programmes of morphogenesis. PMID:24026122
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Highly effective fungal inactivation in He+O2 atmospheric-pressure nonequilibrium plasmas
NASA Astrophysics Data System (ADS)
Xiong, Z.; Lu, X. P.; Feng, A.; Pan, Y.; Ostrikov, K.
2010-12-01
Highly effective (more than 99.9%) inactivation of a pathogenic fungus Candida albicans commonly found in oral, respiratory, digestive, and reproduction systems of a human body using atmospheric-pressure plasma jets sustained in He+O2 gas mixtures is reported. The inactivation is demonstrated in two fungal culture configurations with open (Petri dish without a cover) and restricted access to the atmosphere (Petri dish with a cover) under specific experimental conditions. It is shown that the fungal inactivation is remarkably more effective in the second configuration. This observation is supported by the scanning and transmission electron microscopy of the fungi before and after the plasma treatment. The inactivation mechanism explains the experimental observations under different experimental conditions and is consistent with the reports by other authors. The results are promising for the development of advanced health care applications.
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Simmons, J M; Ackermann, R F; Gallistel, C R
1998-10-15
Lesions in the medial forebrain bundle rostral to a stimulating electrode have variable effects on the rewarding efficacy of self-stimulation. We attempted to account for this variability by measuring the anatomical and functional effects of electrolytic lesions at the level of the lateral hypothalamus (LH) and by correlating these effects to postlesion changes in threshold pulse frequency (pps) for self-stimulation in the ventral tegmental area (VTA). We implanted True Blue in the VTA and compared cell labeling patterns in forebrain regions of intact and lesioned animals. We also compared stimulation-induced regional [14C]deoxyglucose (DG) accumulation patterns in the forebrains of intact and lesioned animals. As expected, postlesion threshold shifts varied: threshold pps remained the same or decreased in eight animals, increased by small but significant amounts in three rats, and increased substantially in six subjects. Unexpectedly, LH lesions did not anatomically or functionally disconnect all forebrain nuclei from the VTA. Most septal and preoptic regions contained equivalent levels of True Blue label in intact and lesioned animals. In both intact and lesioned groups, VTA stimulation increased metabolic activity in the fundus of the striatum (FS), the nucleus of the diagonal band, and the medial preoptic area. On the other hand, True Blue labeling demonstrated anatomical disconnection of the accumbens, FS, substantia innominata/magnocellular preoptic nucleus (SI/MA), and bed nucleus of the stria terminalis. [14C]DG autoradiography indicated functional disconnection of the lateral preoptic area and SI/MA. Correlations between patterns of True Blue labeling or [14C]deoxyglucose accumulation and postlesion shifts in threshold pulse frequency were weak and generally negative. These direct measures of connectivity concord with the behavioral measures in suggesting a diffuse net-like connection between forebrain nuclei and the VTA.
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Anaclet, Christelle; De Luca, Roberto; Venner, Anne; Malyshevskaya, Olga; Lazarus, Michael; Arrigoni, Elda; Fuller, Patrick M
2018-05-07
Recent studies have identified an especially important role for basal forebrain GABAergic (BF VGAT ) neurons in the regulation of behavioral waking and fast cortical rhythms associated with cognition. However, BF VGAT neurons comprise several neurochemically and anatomically distinct sub-populations, including parvalbumin- and somatostatin-containing BF VGAT neurons (BF Parv and BF SOM ), and it was recently reported that optogenetic activation of BF SOM neurons increases the probability of a wakefulness to non-rapid-eye movement (NREM) sleep transition when stimulated during the animal's rest period. This finding was unexpected given that most BF SOM neurons are not NREM sleep active and that central administration of the synthetic SOM analog, octreotide, suppresses NREM sleep or increases REM sleep. Here we employed a combination of genetically-driven chemogenetic and optogenetic activation, chemogenetic inhibition and ablation approaches to further explore the in vivo role of BF SOM neurons in arousal control. Our findings indicate that acute activation or inhibition of BF SOM neurons is neither wakefulness- nor NREM sleep-promoting, is without significant effect on the EEG, and that chronic loss of these neurons is without effect on total 24h sleep amounts, although a small but significant increase in waking was observed in the lesioned mice during the early active period. Our in vitro cell recordings further reveal electrophysiological heterogeneity in BF SOM neurons, specifically suggesting at least two distinct sub-populations. Taken together our data support the more nuanced view that BF SOM are electrically heterogeneous and are not NREM sleep- or wake-promoting per se , but may exert, in particular during the early active period, a modest inhibitory influence on arousal circuitry. SIGNIFICANCE STATEMENT The cellular basal forebrain (BF) is a highly complex area of the brain that is implicated in a wide-range of higher-level neurobiological processes, including regulating and maintaining normal levels of electrocortical and behavioral arousal. The respective in vivo roles of BF cell populations and their neurotransmitter systems in the regulation of electrocortical and behavioral arousal remains incompletely understood. Here we seek to define the neurobiological contribution of GABAergic somatostanin-containing BF neurons to arousal control. Understanding the respective contribution of BF cell populations to arousal control may provide critical insight into the pathogenesis of a host of neuropsychiatric and neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, schizophrenia and the cognitive impairments of normal aging. Copyright © 2018 the authors.
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Time course of the dependence of associative memory retrieval on the entorhinal cortex.
Chen, Xi; Liao, Zhengli; Wong, Yin Ting; Guo, Yiping; He, Jufang
2014-12-01
As the gateway between the hippocampal system and the neocortex, the entorhinal cortex (EC) is hypothesized to be the hub in which the transformation of recent memory to remote memory is processed. We explored the role of the EC on the retrieval of recent and remote associative fear memory. A within-subject approach was adopted to compare the freezing rates of rats in EC intact and EC inactivated conditions following trace fear conditioning. The EC was inactivated by infusing an AMPA antagonist. The fear conditioning used a combined visual and auditory conditioned stimulus with a foot shock. On week 1 following the conditioning, the rats in the EC intact condition exhibited a freezing rate of 92.4±9.5% in response to the light stimulus compared with a 6.3±7.9% freezing rate in the EC inactivated condition. The freezing rates were 87.0±17.8% and 4.7±6.5% on week 2 in the EC intact and inactivated conditions, respectively. These results indicate that the EC participates in the retrieval of associative memory. Extinction of the fear memory was observed in the EC intact condition, as the mean freezing rate decreased to 62.7±23.0% on week 4 and 41.2±26.4% on week 5. However, the freezing rate increased to 26.8±14.2% on week 4 and 22.3±14.4% on week 5 in the EC inactivated condition. The normalized dependence of fear memory retrieval on the EC was 93.2±8.3% on week 1, and significantly decreased on weeks 4 and 5. In summary, the retrieval of associative memory depends on the EC, but this dependence decreases over time. Copyright © 2014 Elsevier Inc. All rights reserved.
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Preissl, Sebastian; Fang, Rongxin; Huang, Hui; Zhao, Yuan; Raviram, Ramya; Gorkin, David U; Zhang, Yanxiao; Sos, Brandon C; Afzal, Veena; Dickel, Diane E; Kuan, Samantha; Visel, Axel; Pennacchio, Len A; Zhang, Kun; Ren, Bing
2018-03-01
Analysis of chromatin accessibility can reveal transcriptional regulatory sequences, but heterogeneity of primary tissues poses a significant challenge in mapping the precise chromatin landscape in specific cell types. Here we report single-nucleus ATAC-seq, a combinatorial barcoding-assisted single-cell assay for transposase-accessible chromatin that is optimized for use on flash-frozen primary tissue samples. We apply this technique to the mouse forebrain through eight developmental stages. Through analysis of more than 15,000 nuclei, we identify 20 distinct cell populations corresponding to major neuronal and non-neuronal cell types. We further define cell-type-specific transcriptional regulatory sequences, infer potential master transcriptional regulators and delineate developmental changes in forebrain cellular composition. Our results provide insight into the molecular and cellular dynamics that underlie forebrain development in the mouse and establish technical and analytical frameworks that are broadly applicable to other heterogeneous tissues.
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Ye, Keping; Feng, Yulin; Wang, Kai; Bai, Yun; Xu, Xinglian; Zhou, Guanghong
2015-06-01
The objective of this work was to study the effect of high hydrostatic pressure combined with moderate heat to inactivate pressure-resistant bacteria in water-boiled salted duck meat (WBSDM), and to establish suitable procedures to improve the quality of WBSDM. The conditions (300 MPa/60 °C, 400 MPa/60 °C, and 500 MPa/50 °C) effectively inactivated the pressure-resistant bacteria (Bacillus cereus and Staphylococcus warneri) in WBSDM. Although more pressure-resistant than S. warneri, the above treatment conditions inactivated B. cereus more than 10(7) CFU/mL in buffer, and more than 10(6) CFU/g in WBSDM, and did not cause any changes in color, texture, or moisture content of products. The interaction between pressure and temperature is a more significant factor than only pressure in inactivating both B. cereus and S. warneri, the treatment of WBSDM at 400 MPa/ 60 °C/ 10 min is the most practical condition for postprocess of WBSDM after cooking. © 2015 Institute of Food Technologists®
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Choe, Katrina Y; Sanchez, Carlos F; Harris, Neil G; Otis, Thomas S; Mathews, Paul J
2018-06-01
Complex animal behavior is produced by dynamic interactions between discrete regions of the brain. As such, defining functional connections between brain regions is critical in gaining a full understanding of how the brain generates behavior. Evidence suggests that discrete regions of the cerebellar cortex functionally project to the forebrain, mediating long-range communication potentially important in motor and non-motor behaviors. However, the connectivity map remains largely incomplete owing to the challenge of driving both reliable and selective output from the cerebellar cortex, as well as the need for methods to detect region specific activation across the entire forebrain. Here we utilize a paired optogenetic and fMRI (ofMRI) approach to elucidate the downstream forebrain regions modulated by activating a region of the cerebellum that induces stereotypical, ipsilateral forelimb movements. We demonstrate with ofMRI, that activating this forelimb motor region of the cerebellar cortex results in functional activation of a variety of forebrain and midbrain areas of the brain, including the hippocampus and primary motor, retrosplenial and anterior cingulate cortices. We further validate these findings using optogenetic stimulation paired with multi-electrode array recordings and post-hoc staining for molecular markers of activated neurons (i.e. c-Fos). Together, these findings demonstrate that a single discrete region of the cerebellar cortex is capable of influencing motor output and the activity of a number of downstream forebrain as well as midbrain regions thought to be involved in different aspects of behavior. Copyright © 2018 Elsevier Inc. All rights reserved.
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Forebrain Mechanisms of Nociception and Pain: Analysis through Imaging
NASA Astrophysics Data System (ADS)
Casey, Kenneth L.
1999-07-01
Pain is a unified experience composed of interacting discriminative, affective-motivational, and cognitive components, each of which is mediated and modulated through forebrain mechanisms acting at spinal, brainstem, and cerebral levels. The size of the human forebrain in relation to the spinal cord gives anatomical emphasis to forebrain control over nociceptive processing. Human forebrain pathology can cause pain without the activation of nociceptors. Functional imaging of the normal human brain with positron emission tomography (PET) shows synaptically induced increases in regional cerebral blood flow (rCBF) in several regions specifically during pain. We have examined the variables of gender, type of noxious stimulus, and the origin of nociceptive input as potential determinants of the pattern and intensity of rCBF responses. The structures most consistently activated across genders and during contact heat pain, cold pain, cutaneous laser pain or intramuscular pain were the contralateral insula and anterior cingulate cortex, the bilateral thalamus and premotor cortex, and the cerebellar vermis. These regions are commonly activated in PET studies of pain conducted by other investigators, and the intensity of the brain rCBF response correlates parametrically with perceived pain intensity. To complement the human studies, we developed an animal model for investigating stimulus-induced rCBF responses in the rat. In accord with behavioral measures and the results of human PET, there is a progressive and selective activation of somatosensory and limbic system structures in the brain and brainstem following the subcutaneous injection of formalin. The animal model and human PET studies should be mutually reinforcing and thus facilitate progress in understanding forebrain mechanisms of normal and pathological pain.
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Gómez-Picos, Patsy; Sifuentes-Romero, Itzel; Merchant-Larios, Horacio; Hernández-Cornejo, Rubí; Díaz-Hernández, Verónica; García-Gasca, Alejandra
2014-01-01
Brain aromatase participates in several biological processes, such as regulation of the reproductive-endocrine axis, memory, stress, sexual differentiation of the nervous system, male sexual behavior, and brain repair. Here we report the isolation and expression of brain aromatase in olive ridley sea turtle (Lepidochelys olivacea) embryos incubated at male- and female-promoting temperatures (MPT and FPT, respectively), at the thermosensitive period (TSP) and the sex-differentiated period. Also, aromatase expression was assessed in differentiated embryos exposed to bisphenol-A (BPA) during the TSP. BPA is a monomer of polycarbonate plastics and is considered an endocrine-disrupting compound. Normal aromatase expression was measured in both forebrain and hindbrain, showing higher expression levels in the forebrain of differentiated embryos at both incubation temperatures. Although no significant differences were detected in the hindbrain, expression was slightly higher at MPT. BPA did not affect aromatase expression neither in forebrains or hindbrains from embryos incubated at MPT, whereas at FPT an inverted U-shape curve was observed in forebrains with significant differences at lower concentrations, whereas in hindbrains a non-significant increment was observed at higher concentrations. Our data indicate that both incubation temperature and developmental stage are critical factors affecting aromatase expression in the forebrain. Because of the timing and location of aromatase expression in the brain, we suggest that brain aromatase may participate in the imprinting of sexual trends related to reproduction and sexual behavior at the onset of sex differentiation, and BPA exposure may impair aromatase function in the female forebrain.
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Curing conditions to inactivate Trichinella spiralis muscle larvae in ready-to-eat pork sausage
USDA-ARS?s Scientific Manuscript database
Curing processes for ready to eat (RTE) pork products currently require individual validation of methods to demonstrate inactivation of Trichinella spiralis. This is a major undertaking for each process; currently no model of meat chemistry exists that can be correlated with inactivation of Trichin...
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Rio-Bermudez, Carlos Del; Kim, Jangjin; Sokoloff, Greta; Blumberg, Mark S.
2017-01-01
Summary Neuronal oscillations comprise a fundamental mechanism by which distant neural structures establish and express functional connectivity. Long-range functional connectivity between the hippocampus and other forebrain structures is enabled by theta oscillations. Here we show for the first time that the infant rat red nucleus (RN)—a brainstem sensorimotor structure— exhibits theta (4-7 Hz) oscillations restricted primarily to periods of active (REM) sleep. At postnatal day (P) 8, theta is expressed as brief bursts immediately following myoclonic twitches; by P12, theta oscillations are expressed continuously across bouts of active sleep. Simultaneous recordings from the hippocampus and RN at P12 show that theta oscillations in both structures are coherent, co-modulated, and mutually interactive during active sleep. Critically, at P12, inactivation of the medial septum eliminates theta in both structures. The developmental emergence of theta-dependent functional coupling between the hippocampus and RN parallels that between the hippocampus and prefrontal cortex. Accordingly, disruptions in the early expression of theta could underlie the cognitive and sensorimotor deficits associated with neurodevelopmental disorders such as autism and schizophrenia. PMID:28479324
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2012-01-01
Background Notch signaling is well recognized as a key regulator of the neuronal fate during embryonic development, but its function in the adult brain is still largely unknown. Mind bomb-1 (Mib1) is an essential positive regulator in the Notch pathway, acting non-autonomously in the signal-sending cells. Therefore, genetic ablation of Mib1 in mature neuron would give valuable insight to understand the cell-to-cell interaction between neurons via Notch signaling for their proper function. Results Here we show that the inactivation of Mib1 in mature neurons in forebrain results in impaired hippocampal dependent spatial memory and contextual fear memory. Consistently, hippocampal slices from Mib1-deficient mice show impaired late-phase, but not early-phase, long-term potentiation and long-term depression without change in basal synaptic transmission at SC-CA1 synapses. Conclusions These data suggest that Mib1-mediated Notch signaling is essential for long-lasting synaptic plasticity and memory formation in the rodent hippocampus. PMID:23111145
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Reward magnitude tracking by neural populations in ventral striatum
Fiallos, Ana M.; Bricault, Sarah J.; Cai, Lili X.; Worku, Hermoon A.; Colonnese, Matthew T.; Westmeyer, Gil; Jasanoff, Alan
2017-01-01
Evaluation of the magnitudes of intrinsically rewarding stimuli is essential for assigning value and guiding behavior. By combining parametric manipulation of a primary reward, medial forebrain bundle (MFB) microstimulation, with functional magnetic imaging (fMRI) in rodents, we delineated a broad network of structures activated by behaviorally characterized levels of rewarding stimulation. Correlation of psychometric behavioral measurements with fMRI response magnitudes revealed regions whose activity corresponded closely to the subjective magnitude of rewards. The largest and most reliable focus of reward magnitude tracking was observed in the shell region of the nucleus accumbens (NAc). Although the nonlinear nature of neurovascular coupling complicates interpretation of fMRI findings in precise neurophysiological terms, reward magnitude tracking was not observed in vascular compartments and could not be explained by saturation of region-specific hemodynamic responses. In addition, local pharmacological inactivation of NAc changed the profile of animals’ responses to rewards of different magnitudes without altering mean reward response rates, further supporting a hypothesis that neural population activity in this region contributes to assessment of reward magnitudes. PMID:27789262
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Highly effective fungal inactivation in He+O{sub 2} atmospheric-pressure nonequilibrium plasmas
DOE Office of Scientific and Technical Information (OSTI.GOV)
Xiong, Z.; Lu, X. P.; Pan, Y.
2010-12-15
Highly effective (more than 99.9%) inactivation of a pathogenic fungus Candida albicans commonly found in oral, respiratory, digestive, and reproduction systems of a human body using atmospheric-pressure plasma jets sustained in He+O{sub 2} gas mixtures is reported. The inactivation is demonstrated in two fungal culture configurations with open (Petri dish without a cover) and restricted access to the atmosphere (Petri dish with a cover) under specific experimental conditions. It is shown that the fungal inactivation is remarkably more effective in the second configuration. This observation is supported by the scanning and transmission electron microscopy of the fungi before and aftermore » the plasma treatment. The inactivation mechanism explains the experimental observations under different experimental conditions and is consistent with the reports by other authors. The results are promising for the development of advanced health care applications.« less
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Berger, Stefan M; Fernández-Lamo, Iván; Schönig, Kai; Fernández Moya, Sandra M; Ehses, Janina; Schieweck, Rico; Clementi, Stefano; Enkel, Thomas; Grothe, Sascha; von Bohlen Und Halbach, Oliver; Segura, Inmaculada; Delgado-García, José María; Gruart, Agnès; Kiebler, Michael A; Bartsch, Dusan
2017-11-17
Dendritic messenger RNA (mRNA) localization and subsequent local translation in dendrites critically contributes to synaptic plasticity and learning and memory. Little is known, however, about the contribution of RNA-binding proteins (RBPs) to these processes in vivo. To delineate the role of the double-stranded RBP Staufen2 (Stau2), we generate a transgenic rat model, in which Stau2 expression is conditionally silenced by Cre-inducible expression of a microRNA (miRNA) targeting Stau2 mRNA in adult forebrain neurons. Known physiological mRNA targets for Stau2, such as RhoA, Complexin 1, and Rgs4 mRNAs, are found to be dysregulated in brains of Stau2-deficient rats. In vivo electrophysiological recordings reveal synaptic strengthening upon stimulation, showing a shift in the frequency-response function of hippocampal synaptic plasticity to favor long-term potentiation and impair long-term depression in Stau2-deficient rats. These observations are accompanied by deficits in hippocampal spatial working memory, spatial novelty detection, and in tasks investigating associative learning and memory. Together, these experiments reveal a critical contribution of Stau2 to various forms of synaptic plasticity including spatial working memory and cognitive management of new environmental information. These findings might contribute to the development of treatments for conditions associated with learning and memory deficits.
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Kurokawa, Daisuke; Sakurai, Yusuke; Inoue, Ai; Nakayama, Rika; Takasaki, Nobuyoshi; Suda, Yoko; Miyake, Tsutomu; Amemiya, Chris T.; Aizawa, Shinichi
2006-01-01
Otx2 is a paired type homeobox gene that plays essential roles in each step and site of head development in vertebrates. In the mouse, Otx2 expression in the anterior neuroectoderm is regulated primarily by two distinct enhancers: anterior neuroectoderm (AN) and forebrain/midbrain (FM) enhancers at 92 kb and 75 kb 5′of the Otx2 locus, respectively. The AN enhancer has activity in the entire anterior neuroectoderm at headfold and early somite stages, whereas the FM enhancer is subsequently active in the future caudal forebrain and midbrain ectoderm. In tetrapods, both AN and FM enhancers are conserved, whereas the AN region is missing in teleosts, despite overt Otx2 expression in the anterior neuroectoderm. Here, we show that zebrafish and fugu FM regions drive expression not only in the forebrain and midbrain but also in the anterior neuroectoderm at headfold stage. The analysis of coelacanth and skate genomic Otx2 orthologues suggests that the utilization of the two enhancers, AN and FM, is an ancestral condition. In contrast, the AN enhancer has been specifically lost in the teleost lineage with a compensatory establishment of AN activity within the FM enhancer. Furthermore, the AN activity in the fish FM enhancer was established by recruiting upstream factors different from those that direct the tetrapod AN enhancer, yet zebrafish FM enhancer is active in both mouse and zebrafish anterior neuroectoderm at the headfold stage. PMID:17159156
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Guo, M; Lu, Y; Garza, J C; Li, Y; Chua, S C; Zhang, W; Lu, B; Lu, X-Y
2012-01-01
The glutamatergic system has been implicated in the pathophysiology of depression and the mechanism of action of antidepressants. Leptin, an adipocyte-derived hormone, has antidepressant-like properties. However, the functional role of leptin receptor (Lepr) signaling in glutamatergic neurons remains to be elucidated. In this study, we generated conditional knockout mice in which the long form of Lepr was ablated selectively in glutamatergic neurons located in the forebrain structures, including the hippocampus and prefrontal cortex (Lepr cKO). Lepr cKO mice exhibit normal growth and body weight. Behavioral characterization of Lepr cKO mice reveals depression-like behavioral deficits, including anhedonia, behavioral despair, enhanced learned helplessness and social withdrawal, with no evident signs of anxiety. In addition, loss of Lepr in forebrain glutamatergic neurons facilitates N-methyl--aspartate (NMDA)-induced hippocampal long-term synaptic depression (LTD), whereas conventional LTD or long-term potentiation (LTP) was not affected. The facilitated LTD induction requires activation of the NMDA receptor GluN2B (NR2B) subunit as it was completely blocked by a selective GluN2B antagonist. Moreover, Lepr cKO mice are highly sensitive to the antidepressant-like behavioral effects of the GluN2B antagonist but resistant to leptin. These results support important roles for Lepr signaling in glutamatergic neurons in regulating depression-related behaviors and modulating excitatory synaptic strength, suggesting a possible association between synaptic depression and behavioral manifestation of behavioral depression. PMID:22408745
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Nord, Alex S.; Pattabiraman, Kartik; Visel, Axel
The forebrain is the seat of higher-order brain functions, and many human neuropsychiatric disorders are due to genetic defects affecting forebrain development, making it imperative to understand the underlying genetic circuitry. We report that recent progress now makes it possible to begin fully elucidating the genomic regulatory mechanisms that control forebrain gene expression. Here, we discuss the current knowledge of how transcription factors drive gene expression programs through their interactions with cis-acting genomic elements, such as enhancers; how analyses of chromatin and DNA modifications provide insights into gene expression states; and how these approaches yield insights into the evolution ofmore » the human brain.« less
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Enhanced recognition memory following glycine transporter 1 deletion in forebrain neurons.
Singer, Philipp; Boison, Detlev; Möhler, Hanns; Feldon, Joram; Yee, Benjamin K
2007-10-01
Selective deletion of glycine transporter 1 (GlyT1) in forebrain neurons enhances N-methyl-D-aspartate receptor (NMDAR)-dependent neurotransmission and facilitates associative learning. These effects are attributable to increases in extracellular glycine availability in forebrain neurons due to reduced glycine re-uptake. Using a forebrain- and neuron-specific GlyT1-knockout mouse line (CamKIIalphaCre; GlyT1tm1.2fl/fI), the authors investigated whether this molecular intervention can affect recognition memory. In a spontaneous object recognition memory test, enhanced preference for a novel object was demonstrated in mutant mice relative to littermate control subjects at a retention interval of 2 hr, but not at 2 min. Furthermore, mutants were responsive to a switch in the relative spatial positions of objects, whereas control subjects were not. These potential procognitive effects were demonstrated against a lack of difference in contextual novelty detection: Mutant and control subjects showed equivalent preference for a novel over a familiar context. Results therefore extend the possible range of potential promnesic effects of specific forebrain neuronal GlyT1 deletion from associative learning to recognition memory and further support the possibility that mnemonic functions can be enhanced by reducing GlyT1 function. (PsycINFO Database Record (c) 2007 APA, all rights reserved).
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Clonal and molecular analysis of the prospective anterior neural boundary in the mouse embryo
Cajal, Marieke; Lawson, Kirstie A.; Hill, Bill; Moreau, Anne; Rao, Jianguo; Ross, Allyson; Collignon, Jérôme; Camus, Anne
2012-01-01
In the mouse embryo the anterior ectoderm undergoes extensive growth and morphogenesis to form the forebrain and cephalic non-neural ectoderm. We traced descendants of single ectoderm cells to study cell fate choice and cell behaviour at late gastrulation. In addition, we provide a comprehensive spatiotemporal atlas of anterior gene expression at stages crucial for anterior ectoderm regionalisation and neural plate formation. Our results show that, at late gastrulation stage, expression patterns of anterior ectoderm genes overlap significantly and correlate with areas of distinct prospective fates but do not define lineages. The fate map delineates a rostral limit to forebrain contribution. However, no early subdivision of the presumptive forebrain territory can be detected. Lineage analysis at single-cell resolution revealed that precursors of the anterior neural ridge (ANR), a signalling centre involved in forebrain development and patterning, are clonally related to neural ectoderm. The prospective ANR and the forebrain neuroectoderm arise from cells scattered within the same broad area of anterior ectoderm. This study establishes that although the segregation between non-neural and neural precursors in the anterior midline ectoderm is not complete at late gastrulation stage, this tissue already harbours elements of regionalisation that prefigure the later organisation of the head. PMID:22186731
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A role for the Swe1 checkpoint kinase during filamentous growth of Saccharomyces cerevisiae.
La Valle, R; Wittenberg, C
2001-01-01
In this study we show that inactivation of Hsl1 or Hsl7, negative regulators of the Swe1 kinase, enhances the invasive behavior of haploid and diploid cells. The enhancement of filamentous growth caused by inactivation of both genes is mediated via the Swe1 protein kinase. Whereas Swe1 contributes noticeably to the effectiveness of haploid invasive growth under all conditions tested, its contribution to pseudohyphal growth is limited to the morphological response under standard assay conditions. However, Swe1 is essential for pseudohyphal differentiation under a number of nonstandard assay conditions including altered temperature and increased nitrogen. Swe1 is also required for pseudohyphal growth in the absence of Tec1 and for the induction of filamentation by butanol, a related phenomenon. Although inactivation of Hsl1 is sufficient to suppress the defect in filamentous growth caused by inactivation of Tec1 or Flo8, it is insufficient to promote filamentous growth in the absence of both factors. Moreover, inactivation of Hsl1 will not bypass the requirement for nitrogen starvation or growth on solid medium for pseudohyphal differentiation. We conclude that the Swe1 kinase modulates filamentous development under a broad spectrum of conditions and that its role is partially redundant with the Tec1 and Flo8 transcription factors. PMID:11404321
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Regulated expression of the Ras effector Rin1 in forebrain neurons
Dzudzor, Bartholomew; Huynh, Lucia; Thai, Minh; Bliss, Joanne M.; Nagaoka, Yoshiko; Wang, Ying; Ch'ng, Toh Hean; Jiang, Meisheng; Martin, Kelsey C.; Colicelli, John
2009-01-01
The Ras effector Rin1 is induced concomitant with synaptogenesis in forebrain neurons, where it inhibits fear conditioning and amygdala LTP. In epithelial cells, lower levels of Rin1 orchestrate receptor endocytosis. A 945bp Rin1 promoter fragment was active in hippocampal neurons and directed accurate tissue-specific and temporal expression in transgenic mice. Regulated expression in neurons and epithelial cells was mediated in part by Snail transcriptional repressors: mutation of a conserved Snail site increased expression and endogenous Snai1 was detected at the Rin1 promoter. We also describe an element closely related to, but distinct from, the consensus site for REST, a master repressor of neuronal genes. Conversion to a consensus REST sequence reduced expression in both cell types. These results provide insight into regulated expression of a neuronal Ras effector, define a promoter useful in telencephalic neuron studies, and describe a novel REST site variant directing expression to mature neurons. PMID:19837165
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Pappas, Samuel S; Darr, Katherine; Holley, Sandra M; Cepeda, Carlos; Mabrouk, Omar S; Wong, Jenny-Marie T; LeWitt, Tessa M; Paudel, Reema; Houlden, Henry; Kennedy, Robert T; Levine, Michael S; Dauer, William T
2015-01-01
Striatal dysfunction plays an important role in dystonia, but the striatal cell types that contribute to abnormal movements are poorly defined. We demonstrate that conditional deletion of the DYT1 dystonia protein torsinA in embryonic progenitors of forebrain cholinergic and GABAergic neurons causes dystonic-like twisting movements that emerge during juvenile CNS maturation. The onset of these movements coincides with selective degeneration of dorsal striatal large cholinergic interneurons (LCI), and surviving LCI exhibit morphological, electrophysiological, and connectivity abnormalities. Consistent with the importance of this LCI pathology, murine dystonic-like movements are reduced significantly with an antimuscarinic agent used clinically, and we identify cholinergic abnormalities in postmortem striatal tissue from DYT1 dystonia patients. These findings demonstrate that dorsal LCI have a unique requirement for torsinA function during striatal maturation, and link abnormalities of these cells to dystonic-like movements in an overtly symptomatic animal model. DOI: http://dx.doi.org/10.7554/eLife.08352.001 PMID:26052670
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A frontal cortex event-related potential driven by the basal forebrain
Nguyen, David P; Lin, Shih-Chieh
2014-01-01
Event-related potentials (ERPs) are widely used in both healthy and neuropsychiatric conditions as physiological indices of cognitive functions. Contrary to the common belief that cognitive ERPs are generated by local activity within the cerebral cortex, here we show that an attention-related ERP in the frontal cortex is correlated with, and likely generated by, subcortical inputs from the basal forebrain (BF). In rats performing an auditory oddball task, both the amplitude and timing of the frontal ERP were coupled with BF neuronal activity in single trials. The local field potentials (LFPs) associated with the frontal ERP, concentrated in deep cortical layers corresponding to the zone of BF input, were similarly coupled with BF activity and consistently triggered by BF electrical stimulation within 5–10 msec. These results highlight the important and previously unrecognized role of long-range subcortical inputs from the BF in the generation of cognitive ERPs. DOI: http://dx.doi.org/10.7554/eLife.02148.001 PMID:24714497
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Feng, Jian; Zhou, Yu; Campbell, Susan L.; Le, Thuc; Li, En; Sweatt, J. David; Silva, Alcino J.; Fan, Guoping
2011-01-01
Dnmt1 and Dnmt3a, two major DNA methyltransferases, are expressed in postmitotic neurons, but their function in the central nervous system (CNS) is unclear. We generated conditional mutant mice that lack either Dnmt1, or Dnmt3a, or both exclusively in forebrain excitatory neurons and found only double knockout (DKO) mice exhibited abnormal hippocampal CA1 long-term plasticity and deficits of learning and memory. While no neuronal loss was found, the size of hippocampal neurons in DKO was smaller; furthermore, DKO neurons showed a deregulation of gene expression including class I MHC and Stat1 that are known to play a role in synaptic plasticity. In addition, we observed a significant decrease in DNA methylation in DKO neurons. We conclude that Dnmt1 and Dnmt3a are required for synaptic plasticity, learning and memory through their overlapping roles in maintaining DNA methylation and modulating neuronal gene expression in adult CNS neurons. PMID:20228804
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Mapping Pathological Phenotypes in a Mouse Model of CDKL5 Disorder
Amendola, Elena; Zhan, Yang; Mattucci, Camilla; Castroflorio, Enrico; Calcagno, Eleonora; Fuchs, Claudia; Lonetti, Giuseppina; Silingardi, Davide; Vyssotski, Alexei L.; Farley, Dominika; Ciani, Elisabetta; Pizzorusso, Tommaso; Giustetto, Maurizio; Gross, Cornelius T.
2014-01-01
Mutations in cyclin-dependent kinase-like 5 (CDKL5) cause early-onset epileptic encephalopathy, a neurodevelopmental disorder with similarities to Rett Syndrome. Here we describe the physiological, molecular, and behavioral phenotyping of a Cdkl5 conditional knockout mouse model of CDKL5 disorder. Behavioral analysis of constitutive Cdkl5 knockout mice revealed key features of the human disorder, including limb clasping, hypoactivity, and abnormal eye tracking. Anatomical, physiological, and molecular analysis of the knockout uncovered potential pathological substrates of the disorder, including reduced dendritic arborization of cortical neurons, abnormal electroencephalograph (EEG) responses to convulsant treatment, decreased visual evoked responses (VEPs), and alterations in the Akt/rpS6 signaling pathway. Selective knockout of Cdkl5 in excitatory and inhibitory forebrain neurons allowed us to map the behavioral features of the disorder to separable cell-types. These findings identify physiological and molecular deficits in specific forebrain neuron populations as possible pathological substrates in CDKL5 disorder. PMID:24838000
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Morales-Pérez, Ariadna A; Maravilla, Pablo; Solís-López, Myriam; Schouwenaars, Rafael; Durán-Moreno, Alfonso; Ramírez-Zamora, Rosa-María
2016-01-01
An experimental design methodology was used to optimize the synthesis of an iron-supported nanocatalyst as well as the inactivation process of Ascaris eggs (Ae) using this material. A factor screening design was used for identifying the significant experimental factors for nanocatalyst support (supported %Fe, (w/w), temperature and time of calcination) and for the inactivation process called the heterogeneous Fenton-like reaction (H2O2 dose, mass ratio Fe/H2O2, pH and reaction time). The optimization of the significant factors was carried out using a face-centered central composite design. The optimal operating conditions for both processes were estimated with a statistical model and implemented experimentally with five replicates. The predicted value of the Ae inactivation rate was close to the laboratory results. At the optimal operating conditions of the nanocatalyst production and Ae inactivation process, the Ascaris ova showed genomic damage to the point that no cell reparation was possible showing that this advanced oxidation process was highly efficient for inactivating this pathogen.
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Factors affecting UV/H2O2 inactivation of Bacillus atrophaeus spores in drinking water.
Zhang, Yongji; Zhang, Yiqing; Zhou, Lingling; Tan, Chaoqun
2014-05-05
This study aims at estimating the performance of the Bacillus atrophaeus spores inactivation by the UV treatment with addition of H2O2. The effect of factors affecting the inactivation was investigated, including initial H2O2 dose, UV irradiance, initial cell density, initial solution pH and various inorganic anions. Under the experimental conditions, the B. atrophaeus spores inactivation followed both the modified Hom Model and the Chick's Model. The results revealed that the H2O2 played dual roles in the reactions, while the optimum reduction of 5.88lg was received at 0.5mM H2O2 for 10min. The inactivation effect was affected by the UV irradiance, while better inactivation effect was achieved at higher irradiance. An increase in the initial cell density slowed down the inactivation process. A slight acid condition at pH 5 was considered as the optimal pH value. The inactivation effect within 10min followed the order of pH 5>pH 7>pH 9>pH 3>pH 11. The effects of three added inorganic anions were investigated and compared, including sulfate (SO4(2)(-)), nitrate (NO3(-)) and carbonate (CO3(2)(-)). The sequence of inactivation effect within 10min followed the order of control group>SO4(2)(-)>NO3(-)>CO3(2)(-). Copyright © 2014 Elsevier B.V. All rights reserved.
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Zebrafish zic2a patterns the forebrain through modulation of Hedgehog-activated gene expression
Sanek, Nicholas A.; Taylor, Aaron A.; Nyholm, Molly K.; Grinblat, Yevgenya
2009-01-01
Summary Holoprosencephaly (HPE) is the most common congenital malformation of the forebrain in human. Several genes with essential roles during forebrain development have been identified because they cause HPE when mutated. Among these are genes that encode the secreted growth factor Sonic hedgehog (Shh) and the transcription factors Six3 and Zic2. In the mouse, Six3 and Shh activate each other's transcription, but a role for Zic2 in this interaction has not been tested. We demonstrate that in zebrafish, as in mouse, Hh signaling activates transcription of six3b in the developing forebrain. zic2a is also activated by Hh signaling, and represses six3b non-cell-autonomously, i.e. outside of its own expression domain, probably through limiting Hh signaling. Zic2a repression of six3b is essential for the correct formation of the prethalamus. The diencephalon-derived optic stalk (OS) and neural retina are also patterned in response to Hh signaling. We show that zebrafish Zic2a limits transcription of the Hh targets pax2a and fgf8a in the OS and retina. The effects of Zic2a depletion in the forebrain and in the OS and retina are rescued by blocking Hh signaling or by increasing levels of the Hh antagonist Hhip, suggesting that in both tissues Zic2a acts to attenuate the effects of Hh signaling. These data uncover a novel, essential role for Zic2a as a modulator of Hh-activated gene expression in the developing forebrain and advance our understanding of a key gene regulatory network that, when disrupted, causes HPE. PMID:19855021
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Zebrafish zic2a patterns the forebrain through modulation of Hedgehog-activated gene expression.
Sanek, Nicholas A; Taylor, Aaron A; Nyholm, Molly K; Grinblat, Yevgenya
2009-11-01
Holoprosencephaly (HPE) is the most common congenital malformation of the forebrain in human. Several genes with essential roles during forebrain development have been identified because they cause HPE when mutated. Among these are genes that encode the secreted growth factor Sonic hedgehog (Shh) and the transcription factors Six3 and Zic2. In the mouse, Six3 and Shh activate each other's transcription, but a role for Zic2 in this interaction has not been tested. We demonstrate that in zebrafish, as in mouse, Hh signaling activates transcription of six3b in the developing forebrain. zic2a is also activated by Hh signaling, and represses six3b non-cell-autonomously, i.e. outside of its own expression domain, probably through limiting Hh signaling. Zic2a repression of six3b is essential for the correct formation of the prethalamus. The diencephalon-derived optic stalk (OS) and neural retina are also patterned in response to Hh signaling. We show that zebrafish Zic2a limits transcription of the Hh targets pax2a and fgf8a in the OS and retina. The effects of Zic2a depletion in the forebrain and in the OS and retina are rescued by blocking Hh signaling or by increasing levels of the Hh antagonist Hhip, suggesting that in both tissues Zic2a acts to attenuate the effects of Hh signaling. These data uncover a novel, essential role for Zic2a as a modulator of Hh-activated gene expression in the developing forebrain and advance our understanding of a key gene regulatory network that, when disrupted, causes HPE.
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Uchida, Sae; Kagitani, Fusako
2017-05-12
The olfactory bulb receives cholinergic basal forebrain input, as does the neocortex; however, the in vivo physiological functions regarding the release of extracellular acetylcholine and regulation of regional blood flow in the olfactory bulb are unclear. We used in vivo microdialysis to measure the extracellular acetylcholine levels in the olfactory bulb of urethane-anesthetized rats. Focal chemical stimulation by microinjection of L-glutamate into the horizontal limb of the diagonal band of Broca (HDB) in the basal forebrain, which is the main source of cholinergic input to the olfactory bulb, increased extracellular acetylcholine release in the ipsilateral olfactory bulb. When the regional cerebral blood flow was measured using laser speckle contrast imaging, the focal chemical stimulation of the HDB did not significantly alter the blood flow in the olfactory bulb, while increases were observed in the neocortex. Our results suggest a functional difference between the olfactory bulb and neocortex regarding cerebral blood flow regulation through the release of acetylcholine by cholinergic basal forebrain input.
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Downregulation of ribosome biogenesis during early forebrain development
Chau, Kevin F; Shannon, Morgan L; Fame, Ryann M; Fonseca, Erin; Mullan, Hillary; Johnson, Matthew B; Sendamarai, Anoop K; Springel, Mark W; Laurent, Benoit
2018-01-01
Forebrain precursor cells are dynamic during early brain development, yet the underlying molecular changes remain elusive. We observed major differences in transcriptional signatures of precursor cells from mouse forebrain at embryonic days E8.5 vs. E10.5 (before vs. after neural tube closure). Genes encoding protein biosynthetic machinery were strongly downregulated at E10.5. This was matched by decreases in ribosome biogenesis and protein synthesis, together with age-related changes in proteomic content of the adjacent fluids. Notably, c-MYC expression and mTOR pathway signaling were also decreased at E10.5, providing potential drivers for the effects on ribosome biogenesis and protein synthesis. Interference with c-MYC at E8.5 prematurely decreased ribosome biogenesis, while persistent c-MYC expression in cortical progenitors increased transcription of protein biosynthetic machinery and enhanced ribosome biogenesis, as well as enhanced progenitor proliferation leading to subsequent macrocephaly. These findings indicate large, coordinated changes in molecular machinery of forebrain precursors during early brain development. PMID:29745900
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NASA Technical Reports Server (NTRS)
Wu, L.; Daunton, N. G.; Krasnov, I. B.; DAmelio, F.; Hyde, T. M.; Sigworth, S. K.
1994-01-01
Quantitative autoradiographic analysis of receptors for GABA and acetylcholine in the forebrain of rats flown on COSMOS 2044 was undertaken as part of a joint US-Soviet study to determine the effects of microgravity on the central nervous system, and in particular on the sensory and motor portions of the forebrain. Changes in binding of these receptors in tissue from animals exposed to microgravity would provide evidence for possible changes in neural processing as a result of exposure to microgravity. Tritium-labelled diazepam and Quinuclidinyl-benzilate (QNB) were used to visualize GABA (benzodiazepine) and muscarinic (cholinergic) receptors, respectively. The density of tritium-labelled radioligands bound to various regions in the forebrain of both flight and control animals were measured from autoradiograms. Data from rats flown in space and from ground-based control animals that were not exposed to microgravity were compared.
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Barradas, P C; Gomes, S S; Cavalcante, L A
1998-01-01
The differentiation of oligodendrocytes in the forebrain of the opossum (Didelphis marsupialis) has been studied by the immunohistochemical identification of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and by the autoradiographic detection of the uptake of 3H-thymidine. CNPase is expressed early in oligodendroglia somata and fibre sheaths (myelin) in the forebrain and its persistence in the cell bodies is regionally heterogeneous, being ephemeral in cells within the optic pathway, supraoptic decussation, and posterior commissure, of intermediate duration in the mamillo-thalamic fascicle, and stria medullaris, and long-lasting in other diencephalic and in telencephalic tracts. In the cerebral cortex, most CNPase+ cells have small somata and multiple processes (types I and II). CNPase-expressing oligodendrocytes are also regionally heterogeneous in terms of proliferative capability, which could not be detected in forebrain tracts or diencephalon, but has appeared in a small proportion of cells in the neocortical white matter and in the fimbria. Our findings provide additional evidence in favour of the heterogeneity of oligodendrocytes.
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Persistence of Infectious Shiga Toxin-Encoding Bacteriophages after Disinfection Treatments
Allué-Guardia, Anna; Martínez-Castillo, Alexandre
2014-01-01
In Shiga toxin-producing Escherichia coli (STEC), induction of Shiga toxin-encoding bacteriophages (Stx phages) causes the release of free phages that can later be found in the environment. The ability of Stx phages to survive different inactivation conditions determines their prevalence in the environment, the risk of stx transduction, and the generation of new STEC strains. We evaluated the infectivity and genomes of two Stx phages (Φ534 and Φ557) under different conditions. Infectious Stx phages were stable at 4, 22, and 37°C and at pH 7 and 9 after 1 month of storage but were completely inactivated at pH 3. Infective Stx phages decreased moderately when treated with UV (2.2-log10 reduction for an estimated UV dose of 178.2 mJ/cm2) or after treatment at 60 and 68°C for 60 min (2.2- and 2.5-log10 reductions, respectively) and were highly inactivated (3 log10) by 10 ppm of chlorine in 1 min. Assays in a mesocosm showed lower inactivation of all microorganisms in winter than in summer. The number of Stx phage genomes did not decrease significantly in most cases, and STEC inactivation was higher than phage inactivation under all conditions. Moreover, Stx phages retained the ability to lysogenize E. coli after some of the treatments. PMID:24463973
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NASA Astrophysics Data System (ADS)
Sarpong, Frederick; Yu, Xiaojie; Zhou, Cunshan; Oteng-Darko, Patricia; Amenorfe, Leticia Peace; Wu, Bengang; Bai, Junwen; Ma, Haile
2018-04-01
Investigating the kinetics of enzyme activities and browning indexes in food are very essential in understanding the enzyme inactivation and browning pigmentation reaction during drying processing. In order to understand and predict accurately the enzyme inactivation and browning pigmentation of banana slices using Relative Humidity (RH)-convective hot air dryer aided by ultrasound (US) pretreatment, this study was conducted. Drying was carried out with 20 kHz frequency of US-pretreatment using three durations (10 20 and 30 min) and RH (10 20 and 30%) conditions at 70 °C and 2.0 m/s air velocity. The kinetic study of both enzyme inactivation and browning pigmentation results were compared to their relevance of fit in terms of coefficient of correlation (R2), the root mean square error (RMSE) and the reduced chi-square (χ 2). First order and second-order polynomial kinetic model fitted well for enzyme inactivation and browning indexes respectively. Both enzymes inactivation kinetics and enzymatic browning index (EBI) declined significantly (p < 0.05) with increasing drying time in all drying conditions and rate of decrease intensified in longer US-pretreatment duration and lower RH conditions. However, shorter US-pretreatment duration and higher RH conditions reduced the non- enzymatic browning index (NBI) significantly. Again, longer US-pretreatment duration and lower RH shortened the drying time but adversely created more microspores from the micrograph study. Longer US pretreatment and lower RH decrease significantly (p < 0.05) the L* and b* values whereas the a* values was increased.
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Lobar holoprosencephaly in a Miniature Schnauzer with hypodipsic hypernatremia.
Sullivan, Stacey A; Harmon, Barry G; Purinton, P Thomas; Greene, Craig E; Glerum, Leigh E
2003-12-15
A 9-month-old male Miniature Schnauzer was examined because of a lifelong history of behavioral abnormalities, including hypodipsia. Diagnostic evaluation revealed marked hypernatremia and a single forebrain ventricle. The behavioral abnormalities did not resolve with correction of the hypernatremia, and the dog was euthanatized. At necropsy, midline forebrain structures were absent or reduced in size, and normally paired forebrain structures were incompletely separated. Findings were diagnostic for holoprosencephaly, a potentially genetic disorder and the likely cause of the hypodipsia. Similar evaluation of affected Miniature Schnauzer dogs may reveal whether holoprosencephaly routinely underlies the thirst deficiency that may be seen in dogs of this breed.
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USDA-ARS?s Scientific Manuscript database
This study examined the inactivation of human norovirus (HuNoV) GI.1 and GII.4 by chlorine under conditions that mimic sewage treatment. Using a porcine gastric mucin-magnetic bead (PGM-MB) assay, no statistically significant loss in HuNoV binding (inactivation) was observed for secondary effluent ...
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Ahmed, W; Richardson, K; Sidhu, J P S; Jagals, P; Toze, S
2014-01-01
In this study, faecal indicator bacteria (FIB) namely Escherichia coli and Enterococcus spp. were seeded into slurries of possum faeces and placed on the roof and in the gutter of a roof-captured rainwater (RCR) system. The persistence of FIB in these circumstances was determined under ambient climatic conditions. FIB persistence was also determined under in situ conditions in tank water using diffusion chambers. The numbers of surviving FIB at different time intervals were enumerated using culture-based methods. Both FIB were rapidly inactivated on the roof under sunlight conditions (T(90) = 2 h) compared with shade conditions (T(90) = 9-53 h). Significant differences were observed between sunlight and shade conditions on the roof for both T90 values of E. coli (P < 0·001) and Enterococcus spp. (P < 0·001). E. coli showed biphasic inactivation patterns under both clean and unclean gutter conditions. Enterococcus spp., however, showed rapid inactivation (T(90) = 2 h for the clean gutter and T(90) = 6 h for the unclean gutter) compared with E. coli (T(90) = 22 h for the clean gutter and T(90) = 20 h for the unclean gutter). Significant differences were also observed between the T(90) values of E. coli and Enterococcus spp. for both clean (P < 0·001) and unclean (P < 0·001) gutters. Both E. coli and Enterococcus spp. showed nonlinear biphasic inactivation in tank water. Significant difference was observed between the T(90) value of E. coli inactivation compared with Enterococcus spp. (P < 0·001) in the tank water. In this study, FIB were observed to survive longer (T(90) = 9-53 h) on the roof under shade conditions compared with sunlight conditions (T(90) = 2 h). If there is a rainfall event within two to three days after the deposition of faecal maters on the roof, it is highly likely that FIB would be transported to the tank water. When introduced into the tank, a relatively slow inactivation process may take place (T(90) = 38-72 h). The presence of FIB in water indicates faecal pollution and potential presence of enteric pathogens. Therefore, the information on the resilience of FIB, as obtained in this study, can be used for indirect assessment of health risks associated with using roof-captured rainwater for potable and nonpotable purposes. © 2013 The Society for Applied Microbiology.
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Vu, Michael T.; Du, Guizhi; Bayliss, Douglas A.
2015-01-01
Basal forebrain cholinergic neurons are the main source of cortical acetylcholine, and their activation by histamine elicits cortical arousal. TWIK-like acid-sensitive K+ (TASK) channels modulate neuronal excitability and are expressed on basal forebrain cholinergic neurons, but the role of TASK channels in the histamine-basal forebrain cholinergic arousal circuit is unknown. We first expressed TASK channel subunits and histamine Type 1 receptors in HEK cells. Application of histamine in vitro inhibited the acid-sensitive K+ current, indicating a functionally coupled signaling mechanism. We then studied the role of TASK channels in modulating electrocortical activity in vivo using freely behaving wild-type (n = 12) and ChAT-Cre:TASKf/f mice (n = 12), the latter lacking TASK-1/3 channels on cholinergic neurons. TASK channel deletion on cholinergic neurons significantly altered endogenous electroencephalogram oscillations in multiple frequency bands. We then identified the effect of TASK channel deletion during microperfusion of histamine into the basal forebrain. In non-rapid eye movement sleep, TASK channel deletion on cholinergic neurons significantly attenuated the histamine-induced increase in 30–50 Hz activity, consistent with TASK channels contributing to histamine action on basal forebrain cholinergic neurons. In contrast, during active wakefulness, histamine significantly increased 30–50 Hz activity in ChAT-Cre:TASKf/f mice but not wild-type mice, showing that the histamine response depended upon the prevailing cortical arousal state. In summary, we identify TASK channel modulation in response to histamine receptor activation in vitro, as well as a role of TASK channels on cholinergic neurons in modulating endogenous oscillations in the electroencephalogram and the electrocortical response to histamine at the basal forebrain in vivo. SIGNIFICANCE STATEMENT Attentive states and cognitive function are associated with the generation of γ EEG activity. Basal forebrain cholinergic neurons are important modulators of cortical arousal and γ activity, and in this study we investigated the mechanism by which these neurons are activated by the wake-active neurotransmitter histamine. We found that histamine inhibited a class of K+ leak channels called TASK channels and that deletion of TASK channels selectively on cholinergic neurons modulated baseline EEG activity as well as histamine-induced changes in γ activity. By identifying a discrete brain circuit where TASK channels can influence γ activity, these results represent new knowledge that enhances our understanding of how subcortical arousal systems may contribute to the generation of attentive states. PMID:26446210
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SURFACE INACTIVATION OF BACTERIAL VIRUSES AND OF PROTEINS
Adams, Mark H.
1948-01-01
1. The seven bacterial viruses of the T group active against E. coli, are rapidly inactivated at gas-liquid interfaces. 2. The kinetics of this inactivation whether brought about by shaking or by bubbling with nitrogen are those of a first order reaction. 3. This inactivation may be prevented by the addition of enough protein to maintain the gas-liquid interface in a saturated condition. 4. The analogy between this phenomenon and the surface denaturation of proteins is pointed out and discussed. PMID:18917025
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Response to deep hypoglycemia does not involve glucoreceptors in carotid perfused tissue
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cane, P.; Haun, C.K.; Evered, J.
1988-11-01
In the present study the authors examined whether the magnified hormonal counter-regulatory response seen during deep hypoglycemia (40 mg/dl) could be attenuated by supplying the forebrain with glucose furnished through carotid infusion. Two protocols were performed in conscious dogs. In the first protocol they infused glucose bilaterally into the carotid circulation to produce a forebrain glycemia of 55 {plus minus} 1 mg/dl whereas systemic glycemia declined to 39 {plus minus} 2 mg/dl. In the second protocol as a control they infused glucose into the systemic circulation at a rate matched to protocol 1 so that both systemic and jugular plasmamore » glucose concentrations were equivalent to the systemic glucose concentrations in protocol 1. In spite of a substantial difference in forebrain glycemia there were no differences in the counter-regulatory responses of catecholamines or glucagon. In addition, through the use of radiolabeled microspheres, they defined the precise regions of the forebrain irrigated during bilateral intracarotid glucose infusions. The concentration of microspheres was high in the forebrain but very low in the hindbrain. The results indicate that glucoreceptor cells in tissues perfused by carotid arteries may play a tautological role in the sympathetic response to hypoglycemia and imply that glucose-sensitive receptors must also be located elsewhere in the central nervous system or in the periphery.« less
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Bañuelos, C.; LaSarge, C. L.; McQuail, J. A.; Hartman, J. J.; Gilbert, R. J.; Ormerod, B. K.; Bizon, J. L.
2013-01-01
Both cholinergic and GABAergic projections from the rostral basal forebrain have been implicated in hippocampal function and mnemonic abilities. While dysfunction of cholinergic neurons has been heavily implicated in age-related memory decline, significantly less is known regarding how age-related changes in co-distributed GABAergic projection neurons contribute to a decline in hippocampal-dependent spatial learning. In the current study, confocal stereology was used to quantify cholinergic (choline acetyltransferase (ChAT) immunopositive) neurons, GABAergic projection (glutamic decarboxylase 67 (GAD67) immunopositive) neurons, and total (NeuN immunopositive) neurons in the rostral basal forebrain of young and aged rats that were first characterized on a spatial learning task. ChAT immunopositive neurons were significantly but modestly reduced in aged rats. Although ChAT immunopositive neuron number was strongly correlated with spatial learning abilities among young rats, the reduction of ChAT immunopositive neurons was not associated with impaired spatial learning in aged rats. In contrast, the number of GAD67 immunopositive neurons was robustly and selectively elevated in aged rats that exhibited impaired spatial learning. Interestingly, the total number of rostral basal forebrain neurons was comparable in young and aged rats, regardless of their cognitive status. These data demonstrate differential effects of age on phenotypically distinct rostral basal forebrain projection neurons, and implicate dysregulated cholinergic and GABAergic septohippocampal circuitry in age-related mnemonic decline. PMID:22817834
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Basaure, Pia; Guardia-Escote, Laia; Cabré, Maria; Peris-Sampedro, Fiona; Sánchez-Santed, Fernando; Domingo, José L; Colomina, Maria Teresa
2018-05-03
Chlorpyrifos (CPF) is one of the most commonly used organophosphate pesticides in the world. Our previous results described that apolipoprotein E (APOE) polymorphisms are a source of individual differences in susceptibility to CPF. The aim of this study was to assess the physical and biochemical effects of postnatal exposure to CPF in the apoE targeted replacement mouse model. Mice were exposed to CPF at 0 or 1 mg/kg/day from postnatal day 10-15. Physical development, plasma and forebrain cholinesterase (ChE) activity and gene expression in liver and forebrain were evaluated. CPF exposure delays physical maturation and decreases the expression of choline acetyltransferase, α4-subunit and the α7 receptor. CPF decreases the expression of vesicular acetylcholine transporter (VAChT) mRNA in the forebrain only in apoE3 mice. The expression of paraoxonase-2 in the forebrain was also influenced by APOE genotype and CPF. Differences between genotypes were observed in litter size, ChE activity, expression of butyrylcholinesterase and paraoxonase-1 in liver and variants of acetylcholinesterase, VAChT and the α7 receptor in the forebrain. These results support that there are different vulnerabilities to postnatal CPF exposure according to the APOE polymorphism, which in turn affects the cholinergic system and defenses to oxidative stress. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Blomstedt, Patric; Naesström, Matilda; Bodlund, Owe
2017-05-01
Deep brain stimulation (DBS) may be considered in severe cases of therapy-refractory major depressive disorder (MDD). However, DBS for MDD is still an experimental therapy. Therefore, it should only be administered in clinical studies driven by multidisciplinary teams, including surgeons with substantial experience of DBS in the treatment of other conditions.
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Glucocorticoids are the consensus treatment to avoid respiratory distress in preterm infants but there is accumulating evidence that these agents evoke long-term neurobehavioral deficits. Earlier, we showed that the developing rat forebrain is far more sensitive to glucocorticoi...
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USDA-ARS?s Scientific Manuscript database
The effect of storage conditions on subsequent high-hydrostatic pressure (HHP) inactivation of V. parahaemolyticus and V. vulnificus in oyster meat was investigated. Live oysters were inoculated with V. parahaemolyticus or V. vulnificus to ca. 7-8 log MPN/g by feeding and stored at different conditi...
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Leroy, Frédéric; Lievens, Kristoff; De Vuyst, Luc
2005-01-01
In mixed cultures, bacteriocin production by the sausage isolate Lactobacillus sakei CTC 494 rapidly inactivated sensitive Listeria innocua LMG 13568 cells, even at low bacteriocin activity levels. A small fraction of the listerial population was bacteriocin resistant. However, sausage fermentation conditions inhibited regrowth of resistant cells. PMID:16269805
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Rhodes, Kenneth J; Carroll, Karen I; Sung, M Amy; Doliveira, Lisa C; Monaghan, Michael M; Burke, Sharon L; Strassle, Brian W; Buchwalder, Lynn; Menegola, Milena; Cao, Jie; An, W Frank; Trimmer, James S
2004-09-08
Voltage-gated potassium (Kv) channels from the Kv4, or Shal-related, gene family underlie a major component of the A-type potassium current in mammalian central neurons. We recently identified a family of calcium-binding proteins, termed KChIPs (Kv channel interacting proteins), that bind to the cytoplasmic N termini of Kv4 family alpha subunits and modulate their surface density, inactivation kinetics, and rate of recovery from inactivation (An et al., 2000). Here, we used single and double-label immunohistochemistry, together with circumscribed lesions and coimmunoprecipitation analyses, to examine the regional and subcellular distribution of KChIPs1-4 and Kv4 family alpha subunits in adult rat brain. Immunohistochemical staining using KChIP-specific monoclonal antibodies revealed that the KChIP polypeptides are concentrated in neuronal somata and dendrites where their cellular and subcellular distribution overlaps, in an isoform-specific manner, with that of Kv4.2 and Kv4.3. For example, immunoreactivity for KChIP1 and Kv4.3 is concentrated in the somata and dendrites of hippocampal, striatal, and neocortical interneurons. Immunoreactivity for KChIP2, KChIP4, and Kv4.2 is concentrated in the apical and basal dendrites of hippocampal and neocortical pyramidal cells. Double-label immunofluorescence labeling revealed that throughout the forebrain, KChIP2 and KChIP4 are frequently colocalized with Kv4.2, whereas in cortical, hippocampal, and striatal interneurons, KChIP1 is frequently colocalized with Kv4.3. Coimmunoprecipitation analyses confirmed that all KChIPs coassociate with Kv4 alpha subunits in brain membranes, indicating that KChIPs 1-4 are integral components of native A-type Kv channel complexes and are likely to play a major role as modulators of somatodendritic excitability.
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Plyler, Kimberly S; Daniels, Derek
2017-09-01
Ghrelin acts in the CNS to decrease fluid intake under a variety of dipsogenic and natriorexigenic conditions. Previous studies on this topic, however, focused on the forebrain as a site of action for this effect of ghrelin. Because the hindbrain contains neural substrates that are capable of mediating the well-established orexigenic effects of ghrelin, the current study tested the hypothesis that ghrelin applied to the hindbrain also would affect fluid intake. To this end, water and saline intakes were stimulated by central injection of angiotensin II (AngII) in rats that also received injections of ghrelin (0.5μg/μl) into either the lateral or fourth ventricle. Ghrelin injected into either ventricle reduced both water and 1.8% NaCl intake that was stimulated by AngII. The nature of the intake effect revealed some differences between the injection sites. For example, forebrain application of ghrelin reduced saline intake by a reduction in both the number of licking bursts and the size of each licking burst, but hindbrain application of ghrelin had a more selective effect on burst number. In an attempt to elucidate a brain structure in which hindbrain-administered ghrelin and forebrain-administered AngII interact to cause the ingestive response, we used Fos-immunohistochemistry in rats given the treatments used in the behavioral experiments. Although several brain areas were found to respond to either ghrelin or AngII, of the sites examined, only the paraventricular nucleus of the hypothalamus (PVN) emerged as a potential site of interaction. Specifically, AngII treatment caused expression of Fos in the PVN that was attenuated by concomitant treatment with ghrelin. These experiments provide the novel finding that the hindbrain contains elements that can respond to ghrelin and cause decreases in AngII-induced fluid intake, and that direct actions by ghrelin on forebrain structures is not necessary. Moreover, these studies suggest that the PVN is an important site of interaction between these two peptides. Copyright © 2016 Elsevier Inc. All rights reserved.
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Annamneedi, Anil; Caliskan, Gürsel; Müller, Sabrina; Montag, Dirk; Budinger, Eike; Angenstein, Frank; Fejtova, Anna; Tischmeyer, Wolfgang; Gundelfinger, Eckart D; Stork, Oliver
2018-06-18
Bassoon is a large scaffolding protein of the presynaptic active zone involved in the development of presynaptic terminals and in the regulation of neurotransmitter release at both excitatory and inhibitory brain synapses. Mice with constitutive ablation of the Bassoon (Bsn) gene display impaired presynaptic function, show sensory deficits and develop severe seizures. To specifically study the role of Bassoon at excitatory forebrain synapses and its relevance for control of behavior, we generated conditional knockout (Bsn cKO) mice by gene ablation through an Emx1 promoter-driven Cre recombinase. In these animals, we confirm selective loss of Bassoon from glutamatergic neurons of the forebrain. Behavioral assessment revealed that, in comparison to wild-type littermates, Bsn cKO mice display selectively enhanced contextual fear memory and increased novelty preference in a spatial discrimination/pattern separation task. These changes are accompanied by an augmentation of baseline synaptic transmission at medial perforant path to dentate gyrus (DG) synapses, as indicated by increased ratios of field excitatory postsynaptic potential slope to fiber volley amplitude. At the structural level, an increased complexity of apical dendrites of DG granule cells can be detected in Bsn cKO mice. In addition, alterations in the expression of cellular maturation markers and a lack of age-dependent decrease in excitability between juvenile and adult Bsn cKO mice are observed. Our data suggest that expression of Bassoon in excitatory forebrain neurons is required for the normal maturation of the DG and important for spatial and contextual memory.
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Sewall, Kendra B.; Dankoski, Elyse C.; Sockman, Keith W.
2010-01-01
Male songbirds often establish territories and attract mates by singing, and some song features can reflect the singer’s condition or quality. The quality of the song environment can change, so male songbirds should benefit from assessing the competitiveness of the song environment and appropriately adjusting their own singing behavior and the neural substrates by which song is controlled. In a wide range of taxa social modulation of behavior is partly mediated by the arginine vasopressin or vasotocin (AVP/AVT) systems. To examine the modulation of singing behavior in response to the quality of the song environment we compared the song output of laboratory-housed male Lincoln’s sparrows (Melospiza lincolnii) exposed to one week of chronic playback of songs categorized as either high or low quality, based on song length, complexity and trill performance. To explore the neural basis of any facultative shifts in behavior, we also quantified the subjects’ AVT immunoreactivity (AVT-IR) in three forebrain regions that regulate socio-sexual behavior: the medial bed nucleus of the stria terminalis (BSTm), the lateral septum (LS) and the preoptic area. We found that high quality songs increased singing effort and reduced AVT-IR in the BSTm and LS, relative to low quality songs. The effect of the quality of the song environment on both singing effort and forebrain AVT-IR raises the hypothesis that AVT within these brain regions plays a role in the modulation of behavior in response to competition that individual males may assess from the prevailing song environment. PMID:20399213
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Travers, Joseph B; Herman, Kenneth; Travers, Susan P
2010-04-01
The appetitive component of feeding is controlled by forebrain substrates, but the consummatory behaviors of licking, mastication, and swallowing are organized in the brainstem. The target of forebrain appetitive signals is unclear but likely includes regions of the medullary reticular formation (RF). This study was undertaken to determine the necessity of different RF regions for mastication induced by a descending appetitive signal. We measured solid food intake in response to third ventricular (3V) infusions of the orexigenic peptide neuropeptide Y 3-36 in awake, freely moving rats and determined whether focal RF infusions of the GABAA agonist muscimol suppressed eating. RF infusions were centered in either the lateral tegmental field, comprising the intermediate (IRt) and parvocellular (PCRt) RF, or in the nucleus gigantocellularis (Gi). Infusions of NPY 3-36 (5 microg/5 microl) into 3V significantly increased feeding of solid food over a 90-min period compared with the noninfused condition (4.3 g +/- 0.56 vs. 0.57 g +/- 0.57, p < .001). NPY 3-36-induced food intake was suppressed (1.7 g +/- 0.48) by simultaneous infusions of muscimol (0.6 mM/100 nl) into the IRt/PCRt (p < .01). Coincident with the decrease in feeding was a decrease in the amplitude of anterior digastric muscle contractions in response to intraoral sucrose infusions. In contrast, infusions of muscimol into Gi had no discernible effect on food intake or EMG amplitude. These data suggest that the IRt/PCRt is essential for forebrain-initiated mastication, but that the Gi is not a necessary link in this pathway.
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Navntoft, C; Ubomba-Jaswa, E; McGuigan, K G; Fernández-Ibáñez, P
2008-12-11
Inactivation kinetics are reported for suspensions of Escherichia coli in well-water using compound parabolic collector (CPC) mirrors to enhance the efficiency of solar disinfection (SODIS) for batch reactors under real, solar radiation (cloudy and cloudless) conditions. On clear days, the system with CPC reflectors achieved complete inactivation (more than 5-log unit reduction in bacterial population to below the detection limit of 4CFU/mL) one hour sooner than the system fitted with no CPC. On cloudy days, only systems fitted with CPCs achieved complete inactivation. Degradation of the mirrors under field conditions was also evaluated. The reflectivity of CPC systems that had been in use outdoors for at least 3 years deteriorated in a non-homogeneous fashion. Reflectivity values for these older systems were found to vary between 27% and 72% compared to uniform values of 87% for new CPC systems. The use of CPC has been proven to be a good technological enhancement to inactivate bacteria under real conditions in clear and cloudy days. A comparison between enhancing optics and thermal effect is also discussed.
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Barber, Melissa; Andrews, William D; Memi, Fani; Gardener, Phillip; Ciantar, Daniel; Tata, Mathew; Ruhrberg, Christiana; Parnavelas, John G
2018-01-01
Abstract Vascular endothelial growth factor (Vegfa) is essential for promoting the vascularization of the embryonic murine forebrain. In addition, it directly influences neural development, although its role in the forming forebrain is less well elucidated. It was recently suggested that Vegfa may influence the development of GABAergic interneurons, inhibitory cells with crucial signaling roles in cortical neuronal circuits. However, the mechanism by which it affects interneuron development remains unknown. Here we investigated the developmental processes by which Vegfa may influence cortical interneuron development by analyzing transgenic mice that ubiquitously express the Vegfa120 isoform to perturb its signaling gradient. We found that interneurons reach the dorsal cortex at mid phases of corticogenesis despite an aberrant vascular network. Instead, endothelial ablation of Vegfa alters cortical interneuron numbers, their intracortical distribution and spatial proximity to blood vessels. We show for the first time that vascular-secreted guidance factors promote early-migrating interneurons in the intact forebrain in vivo and identify a novel role for vascular-Vegfa in this process. PMID:29901792
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Baxter, Mark G; Bucci, David J
2013-10-01
The advent of the selective cholinergic toxin, 192 IgG-saporin, dramatically shaped subsequent research on the role of the basal forebrain in learning and memory. In particular, several articles (including the authors' 1995 Behavioral Neuroscience paper; M. G. Baxter, D. J. Bucci, L. K., Gorman, R. G. Wiley, & M. Gallagher, 1995) revealed that selective removal of basal forebrain cholinergic neurons had surprisingly little effect on spatial learning and memory. Here, as part of the series commemorating the 30th anniversary of Behavioral Neuroscience, we describe how our earlier findings prompted a reconsideration of the cholinergic contribution to cognitive function and also led to several new research directions, including renewed interest in basal forebrain GABA-ergic neurons and cholinergic contributions to neurocognitive development. The authors also describe how the successful use of 192 IgG-saporin led to the development and popularity of a wide range of selective new neurotoxic agents. Finally, they consider the utility of the permanent lesion approach in the wake of new transgenic and optogenetic methods. 2013 APA, all rights reserved
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Terefe, Netsanet Shiferaw; Buckow, Roman; Versteeg, Cornelis
2015-01-01
High-power ultrasound is a versatile technology which can potentially be used in many food processing applications including food preservation. This is part 2 of a series of review articles dealing with the effectiveness of nonthermal food processing technologies in food preservation focusing on their effect on enzymes. Typically, ultrasound treatment alone does not efficiently cause microbial or enzyme inactivation sufficient for food preservation. However, combined with mild heat with or without elevated pressure (P ≤ 500 kPa), ultrasound can effectively inactivate enzymes and microorganisms. Synergistic effects between ultrasound and mild heat have been reported for the inactivation of both enzymes and microorganisms. The application of ultrasound has been shown to enhance the rate of inactivation of quality degrading enzymes including pectin methylesterase (PME), polygalacturonase (PG), peroxidase (POD), polyphenol oxidase (PPO), and lipoxygenase (LOX) at mild temperature by up to 400 times. Moreover, ultrasound enables the inactivation of relatively heat-resistant enzymes such as tomato PG1 and thermostable orange PME at mild temperature conditions. The extent to which ultrasound enhances the inactivation rate depends on the type of enzyme, the medium in which the enzyme is suspended, and the processing condition including frequency, ultrasonic intensity, temperature, and pressure. The physical and chemical effects of cavitation are considered to be responsible for the ultrasound-induced inactivation of enzymes, although the dominant mechanism depends on the structure of the enzyme.
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Bacteria and fungi inactivation by photocatalysis under UVA irradiation: liquid and gas phase.
Rodrigues-Silva, Caio; Miranda, Sandra M; Lopes, Filipe V S; Silva, Mário; Dezotti, Márcia; Silva, Adrián M T; Faria, Joaquim L; Boaventura, Rui A R; Vilar, Vítor J P; Pinto, Eugénia
2017-03-01
In the last decade, environmental risks associated with wastewater treatment plants (WWTPs) have become a concern in the scientific community due to the absence of specific legislation governing the occupational exposure limits (OEL) for microorganisms present in indoor air. Thus, it is necessary to develop techniques to effectively inactivate microorganisms present in the air of WWTPs facilities. In the present work, ultraviolet light A radiation was used as inactivation tool. The microbial population was not visibly reduced in the bioaerosol by ultraviolet light A (UVA) photolysis. The UVA photocatalytic process for the inactivation of microorganisms (bacteria and fungi, ATCC strains and isolates from indoor air samples of a WWTP) using titanium dioxide (TiO 2 P25) and zinc oxide (ZnO) was tested in both liquid-phase and airborne conditions. In the slurry conditions at liquid phase, P25 showed a better performance in inactivation. For this reason, gas-phase assays were performed in a tubular photoreactor packed with cellulose acetate monolithic structures coated with P25. The survival rate of microorganisms under study decreased with the catalyst load and the UVA exposure time. Inactivation of fungi was slower than resistant bacteria, followed by Gram-positive bacteria and Gram-negative bacteria. Graphical abstract Inactivation of fungi and bacteria in gas phase by photocatalitic process performed in a tubular photoreactor packed with cellulose acetate monolith structures coated with TiO 2 .
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ERIC Educational Resources Information Center
Kelly, Michele P.; Cheung, York-Fong; Favilla, Christopher; Siegel, Steven J.; Kanes, Stephen J.; Houslay, Miles D.; Abel, Ted
2008-01-01
Memory formation requires cAMP signaling; thus, this cascade has been of great interest in the search for cognitive enhancers. Given that medications are administered long-term, we determined the effects of chronically increasing cAMP synthesis in the brain by expressing a constitutively active isoform of the G-protein subunit G[alpha]s…
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Kang, Jun Il; Groleau, Marianne; Dotigny, Florence; Giguère, Hugo; Vaucher, Elvire
2014-07-01
The cholinergic afferents from the basal forebrain to the primary visual cortex play a key role in visual attention and cortical plasticity. These afferent fibers modulate acute and long-term responses of visual neurons to specific stimuli. The present study evaluates whether this cholinergic modulation of visual neurons results in cortical activity and visual perception changes. Awake adult rats were exposed repeatedly for 2 weeks to an orientation-specific grating with or without coupling this visual stimulation to an electrical stimulation of the basal forebrain. The visual acuity, as measured using a visual water maze before and after the exposure to the orientation-specific grating, was increased in the group of trained rats with simultaneous basal forebrain/visual stimulation. The increase in visual acuity was not observed when visual training or basal forebrain stimulation was performed separately or when cholinergic fibers were selectively lesioned prior to the visual stimulation. The visual evoked potentials show a long-lasting increase in cortical reactivity of the primary visual cortex after coupled visual/cholinergic stimulation, as well as c-Fos immunoreactivity of both pyramidal and GABAergic interneuron. These findings demonstrate that when coupled with visual training, the cholinergic system improves visual performance for the trained orientation probably through enhancement of attentional processes and cortical plasticity in V1 related to the ratio of excitatory/inhibitory inputs. This study opens the possibility of establishing efficient rehabilitation strategies for facilitating visual capacity.
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Keimpema, Erik; Zheng, Kang; Barde, Swapnali Shantaram; Berghuis, Paul; Dobszay, Márton B; Schnell, Robert; Mulder, Jan; Luiten, Paul G M; Xu, Zhiqing David; Runesson, Johan; Langel, Ülo; Lu, Bai; Hökfelt, Tomas; Harkany, Tibor
2014-12-01
The distribution and (patho-)physiological role of neuropeptides in the adult and aging brain have been extensively studied. Galanin is an inhibitory neuropeptide that can coexist with γ-aminobutyric acid (GABA) in the adult forebrain. However, galanin's expression sites, mode of signaling, impact on neuronal morphology, and colocalization with amino acid neurotransmitters during brain development are less well understood. Here, we show that galaninergic innervation of cholinergic projection neurons, which preferentially express galanin receptor 2 (GalR2) in the neonatal mouse basal forebrain, develops by birth. Nerve growth factor (NGF), known to modulate cholinergic morphogenesis, increases GalR2 expression. GalR2 antagonism (M871) in neonates reduces the in vivo expression and axonal targeting of the vesicular acetylcholine transporter (VAChT), indispensable for cholinergic neurotransmission. During cholinergic neuritogenesis in vitro, GalR2 can recruit Rho-family GTPases to induce the extension of a VAChT-containing primary neurite, the prospective axon. In doing so, GalR2 signaling dose-dependently modulates directional filopodial growth and antagonizes NGF-induced growth cone differentiation. Galanin accumulates in GABA-containing nerve terminals in the neonatal basal forebrain, suggesting its contribution to activity-driven cholinergic development during the perinatal period. Overall, our data define the cellular specificity and molecular complexity of galanin action in the developing basal forebrain. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Adult forebrain NMDA receptors gate social motivation and social memory.
Jacobs, Stephanie; Tsien, Joe Z
2017-02-01
Motivation to engage in social interaction is critical to ensure normal social behaviors, whereas dysregulation in social motivation can contribute to psychiatric diseases such as schizophrenia, autism, social anxiety disorders and post-traumatic stress disorder (PTSD). While dopamine is well known to regulate motivation, its downstream targets are poorly understood. Given the fact that the dopamine 1 (D1) receptors are often physically coupled with the NMDA receptors, we hypothesize that the NMDA receptor activity in the adult forebrain principal neurons are crucial not only for learning and memory, but also for the proper gating of social motivation. Here, we tested this hypothesis by examining sociability and social memory in inducible forebrain-specific NR1 knockout mice. These mice are ideal for exploring the role of the NR1 subunit in social behavior because the NR1 subunit can be selectively knocked out after the critical developmental period, in which NR1 is required for normal development. We found that the inducible deletion of the NMDA receptors prior to behavioral assays impaired, not only object and social recognition memory tests, but also resulted in profound deficits in social motivation. Mice with ablated NR1 subunits in the forebrain demonstrated significant decreases in sociability compared to their wild type counterparts. These results suggest that in addition to its crucial role in learning and memory, the NMDA receptors in the adult forebrain principal neurons gate social motivation, independent of neuronal development. Copyright © 2016 Elsevier Inc. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Tomiyama, Ken-ichi; Funada, Masahiko, E-mail: mfunada@ncnp.go.jp
2014-01-01
The abuse of herbal products containing synthetic cannabinoids has become an issue of public concern. The purpose of this paper was to evaluate the acute cytotoxicity of synthetic cannabinoids on mouse brain neuronal cells. Cytotoxicity induced by synthetic cannabinoid (CP-55,940, CP-47,497, CP-47,497-C8, HU-210, JWH-018, JWH-210, AM-2201, and MAM-2201) was examined using forebrain neuronal cultures. These synthetic cannabinoids induced cytotoxicity in the forebrain cultures in a concentration-dependent manner. The cytotoxicity was suppressed by preincubation with the selective CB{sub 1} receptor antagonist AM251, but not with the selective CB{sub 2} receptor antagonist AM630. Furthermore, annexin-V-positive cells were found among the treated forebrainmore » cells. Synthetic cannabinoid treatment induced the activation of caspase-3, and preincubation with a caspase-3 inhibitor significantly suppressed the cytotoxicity. These synthetic cannabinoids induced apoptosis through a caspase-3-dependent mechanism in the forebrain cultures. Our results indicate that the cytotoxicity of synthetic cannabinoids towards primary neuronal cells is mediated by the CB{sub 1} receptor, but not by the CB{sub 2} receptor, and further suggest that caspase cascades may play an important role in the apoptosis induced by these synthetic cannabinoids. In conclusion, excessive synthetic cannabinoid abuse may present a serious acute health concern due to neuronal damage or deficits in the brain. - Highlights: • Synthetic cannabinoids (classical cannabinoids, non-classical cannabinoids, and aminoalkylindole derivatives) induce cytotoxicity in mouse forebrain cultures. • Synthetic cannabinoid-induced cytotoxicity towards forebrain cultures is mediated by the CB{sub 1} receptor, but not by the CB{sub 2} receptor, and involves caspase-dependent apoptosis. • A high concentration of synthetic cannabinoids may be toxic to neuronal cells that express CB{sub 1} receptors.« less
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Coleman, Leon G.; He, Jun; Lee, Joohwi; Styner, Martin; Crews, Fulton T.
2013-01-01
Background Binge-drinking is common in human adolescents. The adolescent brain is undergoing structural maturation and has a unique sensitivity to alcohol neurotoxicity. Therefore, adolescent binge ethanol may have long-term effects on the adult brain that alter brain structure and behaviors that are relevant to alcohol use disorders. Methods In order to determine if adolescent ethanol binge drinking alters the adult brain, male C57BL/6 mice were treated with either water or ethanol during adolescence (5g/kg/day i.g., post-natal days P28-37) and assessed during adulthood (P60-P88). An array of neurotransmitter-specific genes, behavioral tests (i.e. reversal learning, prepulse inhibition, and open field), and post-mortem brain structure using MRI and immunohistochemistry, were employed to assess persistent alterations in adult brain. Results At P38, 24 hours after adolescent ethanol (AE) binge, many neurotransmitter genes, particularly cholinergic and dopaminergic, were reduced by ethanol treatment. Interestingly, dopamine receptor type 4 mRNA was reduced and confirmed using immunohistochemistry. Normal control maturation (P38-P88) resulted in decreased neurotransmitter mRNA, e.g. an average decrease of 56%. Following adolescent ethanol treatment, adults showed greater gene expression reductions than controls, averaging 73%. Adult spatial learning assessed in the Morris water maze was not changed by adolescent ethanol treatment, but reversal learning experiments revealed deficits. Assessment of adult brain region volumes using MRI indicated that the olfactory bulb and basal forebrain were smaller in adults following adolescent ethanol. Immunohistochemical analyses found reduced basal forebrain area and fewer basal forebrain cholinergic neurons. Conclusions Adolescent binge ethanol treatment reduces adult neurotransmitter gene expression, particularly cholinergic genes, reduces basal forebrain and olfactory bulb volumes, and causes a reduction in the density of basal forebrain acetylcholine neurons. Loss of cholinergic neurons and forebrain structure could underlie adult reversal learning deficits following adolescent binge drinking. PMID:21223304
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Thalamic reticular nucleus in Caiman crocodilus: Relationship with the dorsal thalamus.
Pritz, M B
2016-05-13
The thalamic reticular nucleus was investigated in one group of crocodilians, Caiman crocodilus. This neuronal aggregate is composed of two parts: a compact portion and a diffuse region made up of scattered cells within the forebrain bundles. In Caiman, both the lateral and medial forebrain bundles project to the telencephalon and the thalamic reticular nucleus is associated with each fiber tract. In the lateral forebrain bundle, the compact area is termed the nucleus of the dorsal peduncle (dorsal peduncular nucleus) while the diffuse part is called the perireticular area. In the medial forebrain bundle, the interstitial nucleus comprises one part of the compact area while another region without a specific neuronal label is also present. Similar to the perireticular cells of the lateral forebrain bundle, scattered cells are also present in the medial forebrain bundle. Morphological features of the thalamic reticular nucleus are revealed with stains for the following: fibers; cells; succinic acid dehydrogenase; and acetylcholinesterase. Regardless of which dorsal thalamic nucleus was injected, a localized region of the thalamic reticular nucleus contained retrogradely labeled cells and anterogradely labeled axons and terminals. This grouping was termed clusters and was felt to represent the densest interconnection between the dorsal thalamus and the reticular nucleus. Using clusters as an index of interconnections, the reticular nucleus was divided into sectors, each of which was associated with a specific dorsal thalamic nucleus. An organization similar to that found in Caiman is present in other sauropsids as well as in mammals. These data suggest that a thalamic reticular nucleus is present in all amniotes and has morphological properties similar to those described in this analysis. Lastly, a hypothesis is presented to explain how the external shape of the reticular nucleus in Caiman might be transformed into the homologous area in a representative bird and mammal. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.
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Rabei, Rana; Kaganovsky, Konstantin; Caprioli, Daniele; Bossert, Jennifer M.; Bonci, Antonello
2014-01-01
In human alcoholics, abstinence is often self-imposed, despite alcohol availability, because of the negative consequences of excessive use. During abstinence, relapse is often triggered by exposure to contexts associated with alcohol use. We recently developed a rat model that captures some features of this human condition: exposure to the alcohol self-administration environment (context A), after punishment-imposed suppression of alcohol self-administration in a different environment (context B), provoked renewal of alcohol seeking in alcohol-preferring P rats. The mechanisms underlying context-induced renewal of alcohol seeking after punishment-imposed abstinence are unknown. Here, we studied the role of the lateral hypothalamus (LH) and its forebrain projections in this effect. We first determined the effect of context-induced renewal of alcohol seeking on Fos (a neuronal activity marker) expression in LH. We next determined the effect of LH reversible inactivation by GABAA + GABAB receptor agonists (muscimol + baclofen) on this effect. Finally, we determined neuronal activation in brain areas projecting to LH during context-induced renewal tests by measuring double labeling of the retrograde tracer cholera toxin subunit B (CTb; injected in LH) with Fos. Context-induced renewal of alcohol seeking after punishment-imposed abstinence was associated with increased Fos expression in LH. Additionally, renewal was blocked by muscimol + baclofen injections into LH. Finally, double-labeling analysis of CTb + Fos showed that context-induced renewal of alcohol seeking after punishment-imposed abstinence was associated with selective activation of accumbens shell neurons projecting to LH. The results demonstrate an important role of LH in renewal of alcohol seeking after punishment-imposed abstinence and suggest a role of accumbens shell projections to LH in this form of relapse. PMID:24872550
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Marchant, Nathan J; Rabei, Rana; Kaganovsky, Konstantin; Caprioli, Daniele; Bossert, Jennifer M; Bonci, Antonello; Shaham, Yavin
2014-05-28
In human alcoholics, abstinence is often self-imposed, despite alcohol availability, because of the negative consequences of excessive use. During abstinence, relapse is often triggered by exposure to contexts associated with alcohol use. We recently developed a rat model that captures some features of this human condition: exposure to the alcohol self-administration environment (context A), after punishment-imposed suppression of alcohol self-administration in a different environment (context B), provoked renewal of alcohol seeking in alcohol-preferring P rats. The mechanisms underlying context-induced renewal of alcohol seeking after punishment-imposed abstinence are unknown. Here, we studied the role of the lateral hypothalamus (LH) and its forebrain projections in this effect. We first determined the effect of context-induced renewal of alcohol seeking on Fos (a neuronal activity marker) expression in LH. We next determined the effect of LH reversible inactivation by GABAA + GABAB receptor agonists (muscimol + baclofen) on this effect. Finally, we determined neuronal activation in brain areas projecting to LH during context-induced renewal tests by measuring double labeling of the retrograde tracer cholera toxin subunit B (CTb; injected in LH) with Fos. Context-induced renewal of alcohol seeking after punishment-imposed abstinence was associated with increased Fos expression in LH. Additionally, renewal was blocked by muscimol + baclofen injections into LH. Finally, double-labeling analysis of CTb + Fos showed that context-induced renewal of alcohol seeking after punishment-imposed abstinence was associated with selective activation of accumbens shell neurons projecting to LH. The results demonstrate an important role of LH in renewal of alcohol seeking after punishment-imposed abstinence and suggest a role of accumbens shell projections to LH in this form of relapse. Copyright © 2014 the authors 0270-6474/14/347447-11$15.00/0.
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Ma, Rong; Cui, Xiaolan
2014-01-01
CHO-derived recombinant proteins for human therapeutic are used commonly. There are noninfectious endogenous retroviruses in CHO cells. Validation study for inactivation process is required. Murine xenotropic gamma retrovirus (X-MulV) is a model virus in validation study. In our previous study, optimum conditions for X-MulV inactivation were sifted. In this study, we performed a further research on low pH inactivation for evaluation of X-MulV clearance in manufacturing of recombinant human TNF-α receptor immunoglobulin G fusion proteins (rhTNF-α) for injection. Cell-based infectivity assay was used for the evaluation of X-MulV clearance. RhTNF-α were spiked with X-MulV and were inactivated at pH 3.60 ∼ 3.90, 25 ± 2 °C, and 0 ∼ 240 min, respectively. Samples incubated at the conditions for 15 ∼ 180 min were not inactivated effectively. For 4 h incubation, log10 reductions were achieved 5.0 log10. Biological activity of rhTNF-α incubated at pH 3.60, 25 °C for 4 h, which was assayed on murine L929 fibroblasts cells, was not affected by low pH. Env gene of X-MulV, which was detected by conventional PCR method for the first time, was not detected after incubation at pH 3.60, and it may be the mechanism of low pH inactivation. Copyright © 2013. Published by Elsevier Ltd.
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NASA Astrophysics Data System (ADS)
Aurioles-López, Verónica; Polo-López, M. Inmaculada; Fernández-Ibáñez, Pilar; López-Malo, Aurelio; Bandala, Erick R.
2016-02-01
The inactivation of Fusarium solani in water was assessed by solar driven Fenton-like processes using three different iron salts: ferric acetylacetonate (Fe(acac)3), ferric chloride (FeCl3) and ferrous sulfate (FeSO4). The experimental conditions tested were [Fe] ≈ 5 mg L-1, [H2O2] ≈ 10 mg L-1 and [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1 mild and high, respectively, and pH 3.0 and 5.0, under solar radiation. The highest inactivation rates were observed at high reaction conditions for the three iron salts tested at pH 5.0 with less than 3.0 kJ L-1 of accumulate energy (QUV) to achieve over 99.9% of F. solani inactivation. Fe(acac)3 was the best iron salt to accomplishing F. solani inactivation. The modified Fermi equation was used to fix the experimental inactivation, data showed it was helpful for modeling the process, adequately describing dose-response curves. Inactivation process using FeSO4 at pH 3.0 was modeled fairly with r2 = 0.98 and 0.99 (mild and high concentration, respectively). Fe(acac)3, FeCl3 and FeSO4 at high concentration (i.e. [Fe] ≈ 10 mg L-1; [H2O2] ≈ 20 mg L-1) and pH 5.0 showed the highest fitting values (r2 = 0.99). Iron salt type showed a remarkable influence on the Fenton-like inactivation process.
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Gómez-Couso, Hipólito; Fontán-Sainz, María; Ares-Mazás, Elvira
2010-01-01
To determine the thermal contribution, independent of ultraviolet radiation, on the inactivation of Cryptosporidium parvum during solar water disinfection procedures (SODIS), oocysts were exposed for 4, 8, and 12 hours to temperatures recorded in polyethylene terephthalate bottles in previous SODIS studies carried out under field conditions. Inclusion/exclusion of the fluorogenic vital dye propidium iodide, spontaneous excystation, and infectivity studies were used to determine the inactivation of oocysts. There was a significant increase in the percentage of oocysts that took up propidium iodide and in the number of oocysts that excysted spontaneously. There was also a significant decrease in the intensity of infection elicited in suckling mice at the end of all exposure times. The results of the study demonstrate the importance of temperature in the inactivation of C. parvum oocysts during application of SODIS under natural conditions. PMID:20064992
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Extensive Lesions of Cholinergic Basal Forebrain Neurons Do Not Impair Spatial Working Memory
ERIC Educational Resources Information Center
Vuckovich, Joseph A.; Semel, Mara E.; Baxter, Mark G.
2004-01-01
A recent study suggests that lesions to all major areas of the cholinergic basal forebrain in the rat (medial septum, horizontal limb of the diagonal band of Broca, and nucleus basalis magnocellularis) impair a spatial working memory task. However, this experiment used a surgical technique that may have damaged cerebellar Purkinje cells. The…
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Reciprocal Inhibitory Interactions Between the Reward-Related Effects of Leptin and Cocaine.
You, Zhi-Bing; Wang, Bin; Liu, Qing-Rong; Wu, Yan; Otvos, Laszlo; Wise, Roy A
2016-03-01
Cocaine is habit-forming because of its ability to enhance dopaminergic neurotransmission in the forebrain. In addition to neuronal inputs, forebrain dopamine circuits are modulated by hormonal influences; one of these is leptin, an adipose-derived hormone that attenuates the rewarding effects of food- and hunger-associated brain stimulation reward. Here we report reciprocal inhibition between the reward-related effects of leptin and the reward-related effects of cocaine in rats. First, we report that cocaine and the expectancy of cocaine each depresses plasma leptin levels. Second, we report that exogenous leptin, given systemically or directly into the ventral tegmental area, attenuates the ability of cocaine to elevate dopamine levels in the nucleus accumbens, the ability of cocaine to establish a conditioned place preference, and the ability of cocaine-predictive stimuli to prolong responding in extinction of cocaine-seeking. Thus, whereas leptin represents an endogenous antagonist of the habit-forming and habit-sustaining effects of cocaine, this antagonism is attenuated by cocaine and comes to be attenuated by the expectancy of cocaine.
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Espinosa-Raya, Judith; Cruz-Raya, Ulises; López-Martínez, Margarita; Picazo, Ofir
2018-01-09
Treatment with 17-β estradiol and progesterone improves the performance of ovariectomized rats in an autoshaping learning task, representing cognitive improvement. To test whether this is attributable to genomic mechanisms, the antiestrogen ICI 182 780 or antiprogesterone RU486 was injected into ovariectomized animals primed previously with estrogen or progesterone, respectively. Compared with the vehicle control, each hormone administered alone produced an elevated expression of choline acetyltransferase and TrkA, along with an improvement in performance on the behavioral test. E2+ICI reverted the increase in these two proteins. However, RU alone elicited higher ChAT expression. With this exception, there was a clear linear regression between the number of conditioned responses and the level of ChAT and TrkA in the basal forebrain. The results suggest that TrkA may be more important than ChAT for regulating autoshaping learning tasks, and that genomic mechanisms in the basal forebrain could possibly underlie hormonal improvement of cognition.
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Pelloux, Yann; Minier-Toribio, Angelica; Hoots, Jennifer K; Bossert, Jennifer M; Shaham, Yavin
2018-01-03
Studies using the renewal procedure showed that basolateral amygdala (BLA) inactivation inhibits context-induced relapse to cocaine-seeking after extinction. Here, we determined whether BLA inactivation would also inhibit context-induced relapse after drug-reinforced responding is suppressed by punishment, an animal model of human relapse after self-imposed abstinence due to adverse consequences of drug use. We also determined the effect of central amygdala (CeA) inactivation on context-induced relapse.We trained rats to self-administer cocaine for 12 d (6 h/d) in Context A and then exposed them to either extinction or punishment training for 8 d in Context B. During punishment, 50% of cocaine-reinforced lever-presses produced an aversive footshock of increasing intensity (0.1-0.5 or 0.7 mA). We then tested the rats for relapse to cocaine seeking in the absence of cocaine or shock in Contexts A and B after BLA or CeA injections of vehicle or GABA agonists (muscimol-baclofen). We then retrained the rats for cocaine self-administration in Context A, repunished or re-extinguished lever pressing in Context B, and retested for relapse after BLA or CeA inactivation.BLA or CeA inactivation decreased context-induced relapse in Context A after extinction in Context B. BLA, but not CeA, inactivation increased context-induced relapse in Context A after punishment in Context B. BLA or CeA inactivation provoked relapse in Context B after punishment but not extinction. Results demonstrate that amygdala's role in relapse depends on the method used to achieve abstinence and highlights the importance of studying relapse under abstinence conditions that more closely mimic the human condition. SIGNIFICANCE STATEMENT Relapse to drug use during abstinence is often provoked by re-exposure to the drug self-administration environment or context. Studies using the established extinction-reinstatement rodent model of drug relapse have shown that inactivation of the basolateral amygdala inhibits context-induced drug relapse after extinction of the drug-reinforced responding. Here, we determined whether basolateral amygdala inactivation would also inhibit relapse after drug-reinforced responding is suppressed by punishment, a model of human relapse after self-imposed abstinence. Unexpectedly, we found that basolateral amygdala inactivation had opposite effects on relapse provoked by re-exposure to the drug self-administration environment after extinction versus punishment. Our results demonstrate that depending on the historical conditions that lead to abstinence, amygdala activity can either promote or inhibit relapse. Copyright © 2018 the authors 0270-6474/18/380051-09$15.00/0.
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Inactivation of Viruses by Benzalkonium Chloride
Armstrong, J. A.; Froelich, E. J.
1964-01-01
Benzalkonium chloride (as Roccal or Zephiran) was found to inactivate influenza, measles, canine distemper, rabies, fowl laryngotracheitis, vaccinia, Semliki Forest, feline pneumonitis, meningopneumonitis, and herpes simplex viruses after 10 min of exposure at 30 C or at room temperature. Poliovirus and encephalomyocarditis virus were not inactivated under the same conditions. It was concluded that all viruses tested were sensitive except members of the picorna group. The literature was reviewed. PMID:4288740
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Timmermans, R A H; Nierop Groot, M N; Nederhoff, A L; van Boekel, M A J S; Matser, A M; Mastwijk, H C
2014-03-03
Pulsed electrical field (PEF) technology can be used for the inactivation of micro-organisms and therefore for preservation of food products. It is a mild technology compared to thermal pasteurization because a lower temperature is used during processing, leading to a better retention of the quality. In this study, pathogenic and spoilage micro-organisms relevant in refrigerated fruit juices were studied to determine the impact of process parameters and juice composition on the effectiveness of the PEF process to inactivate the micro-organisms. Experiments were performed using a continuous-flow PEF system at an electrical field strength of 20 kV/cm with variable frequencies to evaluate the inactivation of Salmonella Panama, Escherichia coli, Listeria monocytogenes and Saccharomyces cerevisiae in apple, orange and watermelon juices. Kinetic data showed that under the same conditions, S. cerevisiae was the most sensitive micro-organism, followed by S. Panama and E. coli, which displayed comparable inactivation kinetics. L. monocytogenes was the most resistant micro-organism towards the treatment conditions tested. A synergistic effect between temperature and electric pulses was observed at inlet temperatures above 35 °C, hence less energy for inactivation was required at higher temperatures. Different juice matrices resulted in a different degree of inactivation, predominantly determined by pH. The survival curves were nonlinear and could satisfactorily be modeled with the Weibull model. Copyright © 2013 Elsevier B.V. All rights reserved.
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Virgen-Ortíz, Jose J; Pedrero, Sara G; Fernandez-Lopez, Laura; Lopez-Carrobles, Nerea; Gorines, Beatriz C; Otero, Cristina; Fernandez-Lafuente, Roberto
2017-01-05
Lipases from Candida antarctica (isoform B) and Rhizomucor miehei (CALB and RML) have been immobilized on octyl-agarose (OC) and further coated with polyethylenimine (PEI) and dextran sulfate (DS). The enzymes just immobilized on OC supports could be easily released from the support using 2% SDS at pH 7, both intact or after thermal inactivation (in fact, after inactivation most enzyme molecules were already desorbed). The coating with PEI and DS greatly reduced the enzyme release during thermal inactivation and improved enzyme stability. However, using OC-CALB/RML-PEI-DS, the full release of the immobilized enzyme to reuse the support required more drastic conditions: a pH value of 3, a buffer concentration over 2 M, and temperatures above 45 °C. However, even these conditions were not able to fully release the thermally inactivated enzyme molecules from the support, being necessary to increase the buffer concentration to 4 M sodium phosphate and decrease the pH to 2.5. The formation of unfolded protein/polymers composites seems to be responsible for this strong interaction between the octyl and some anionic groups of OC supports. The support could be reused five cycles using these conditions with similar loading capacity of the support and stability of the immobilized enzyme.
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Evans, Andrew K.; Strassmann, Patrick S.; Lee, I-Ping; Sapolsky, Robert M.
2014-01-01
Toxoplasma gondii (T. gondii) is one of the world’s most successful brain parasites. T. gondii engages in parasite manipulation of host behavior and infection has been epidemiologically linked to numerous psychiatric disorders. Mechanisms by which T. gondii alters host behavior are not well understood, but neuroanatomical cyst presence and the localized host immune response to cysts are potential candidates. The aim of these studies was to test the hypothesis that T. gondii manipulation of specific host behaviors is dependent on neuroanatomical location of cysts in a time-dependent function post-infection. We examined neuroanatomical cyst distribution (53 forebrain regions) in infected rats after predator odor aversion behavior and anxiety-related behavior in the elevated plus maze and open field arena, across a 6-week time course. In addition, we examined evidence for microglial response to the parasite across the time course. Our findings demonstrate that while cysts are randomly distributed throughout the forebrain, individual variation in cyst localization, beginning 3 weeks post-infection, can explain individual variation in the effects of T. gondii on behavior. Additionally, not all infected rats develop cysts in the forebrain, and attenuation of predator odor aversion and changes in anxiety-related behavior are linked with cyst presence in specific forebrain areas. Finally, the immune response to cysts is striking. These data provide the foundation for testing hypotheses about proximate mechanisms by which T. gondii alters behavior in specific brain regions, including consequences of establishment of a homeostasis between T. gondii and the host immune response. PMID:24269877
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Cholinergic Inputs from Basal Forebrain Add an Excitatory Bias to Odor Coding in the Olfactory Bulb
Rothermel, Markus; Carey, Ryan M.; Puche, Adam; Shipley, Michael T.
2014-01-01
Cholinergic modulation of central circuits is associated with active sensation, attention, and learning, yet the neural circuits and temporal dynamics underlying cholinergic effects on sensory processing remain unclear. Understanding the effects of cholinergic modulation on particular circuits is complicated by the widespread projections of cholinergic neurons to telencephalic structures that themselves are highly interconnected. Here we examined how cholinergic projections from basal forebrain to the olfactory bulb (OB) modulate output from the first stage of sensory processing in the mouse olfactory system. By optogenetically activating their axons directly in the OB, we found that cholinergic projections from basal forebrain regulate OB output by increasing the spike output of presumptive mitral/tufted cells. Cholinergic stimulation increased mitral/tufted cell spiking in the absence of inhalation-driven sensory input and further increased spiking responses to inhalation of odorless air and to odorants. This modulation was rapid and transient, was dependent on local cholinergic signaling in the OB, and differed from modulation by optogenetic activation of cholinergic neurons in basal forebrain, which led to a mixture of mitral/tufted cell excitation and suppression. Finally, bulbar cholinergic enhancement of mitral/tufted cell odorant responses was robust and occurred independent of the strength or even polarity of the odorant-evoked response, indicating that cholinergic modulation adds an excitatory bias to mitral/tufted cells as opposed to increasing response gain or sharpening response spectra. These results are consistent with a role for the basal forebrain cholinergic system in dynamically regulating the sensitivity to or salience of odors during active sensing of the olfactory environment. PMID:24672011
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Sakharkar, Amul J; Singru, Praful S; Sarkar, Koustav; Subhedar, Nishikant K
2005-08-22
We studied the organization of the neuropeptide Y (NPY)-immunoreactive system in the forebrain of adult male cichlid fish Oreochromis mossambicus and its response to castration and testosterone replacement by using morphometric methods. Immunoreactivity for NPY was widely distributed in the forebrain, and the pattern generally resembled that in other teleosts. Whereas immunoreactivity was conspicuous in the ganglia of nervus terminalis (NT; or nucleus olfactoretinalis), a weak reaction was detected in some granule cells in the olfactory bulb and in the cells of area ventralis telencephali pars lateralis (Vl). Moderately to intensely immunoreactive cells were distinctly seen in the nucleus entopeduncularis (NE), nucleus preopticus (NPO), nucleus lateralis tuberis (NLT), paraventricular organ (PVO), and midbrain tegmentum (MT). NPY fibers were widely distributed in the forebrain. Castration for 10/15 days resulted in a drastic loss of immunoreactivity in the cells of NE (P<0.001) and a significant decrease (P<0.01) in their cell nuclear size. However, cell nuclei of the NT neurons showed a significant increase in size. A highly significant reduction in the NPY-immunoreactive fiber density (P<0.001) was observed in several areas of the forebrain. Although testosterone replacement reversed these changes, fibers in some areas showed supranormal responses. Immunoreactive cells in Vl, NPO, NLT, PVO, and MT and fiber density in some other areas did not respond to castration. We suggest that the NPY-immunoreactive elements that respond to castration and testosterone replacement may serve as the substrate for processing the positive feedback action of the steroid hormone. (c) 2005 Wiley-Liss, Inc.
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Judson, Matthew C; Bergman, Mica Y; Campbell, Daniel B; Eagleson, Kathie L; Levitt, Pat
2009-04-10
The establishment of appropriate neural circuitry depends on the coordination of multiple developmental events across space and time. These events include proliferation, migration, differentiation, and survival-all of which can be mediated by hepatocyte growth factor (HGF) signaling through the Met receptor tyrosine kinase. We previously found a functional promoter variant of the MET gene to be associated with autism spectrum disorder, suggesting that forebrain circuits governing social and emotional function may be especially vulnerable to developmental disruptions in HGF/Met signaling. However, little is known about the spatiotemporal distribution of Met expression in the forebrain during the development of such circuits. To advance our understanding of the neurodevelopmental influences of Met activation, we employed complementary Western blotting, in situ hybridization, and immunohistochemistry to comprehensively map Met transcript and protein expression throughout perinatal and postnatal development of the mouse forebrain. Our studies reveal complex and dynamic spatiotemporal patterns of expression during this period. Spatially, Met transcript is localized primarily to specific populations of projection neurons within the neocortex and in structures of the limbic system, including the amygdala, hippocampus, and septum. Met protein appears to be principally located in axon tracts. Temporally, peak expression of transcript and protein occurs during the second postnatal week. This period is characterized by extensive neurite outgrowth and synaptogenesis, supporting a role for the receptor in these processes. Collectively, these data suggest that Met signaling may be necessary for the appropriate wiring of forebrain circuits, with particular relevance to the social and emotional dimensions of behavior. (c) 2009 Wiley-Liss, Inc.
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Reassessment of the structural basis of the ascending arousal system
Fuller, Patrick M.; Sherman, David; Pedersen, Nigel P.; Saper, Clifford B.; Lu, Jun
2011-01-01
The “ascending reticular activating system” theory proposed that neurons in the upper brainstem reticular formation projected to forebrain targets that promoted wakefulness. More recent formulations have emphasized that most neurons at the pontomesencepahlic junction that participate in these pathways are actually in monoaminergic and cholinergic cell groups. However, cell-specific lesions of these cell groups have never been able to reproduce the deep coma seen after acute paramedian midbrain lesions that transect ascending axons at the caudal midbrain level. To determine whether the cortical afferents from the thalamus or the basal forebrain were more important in maintaining arousal, we first place large cell-body specific lesions in these targets. Surprisingly, extensive thalamic lesions had little effect on EEG or behavioral measures of wakefulness or on c-Fos expression by cortical neurons during wakefulness. In contrast, animals with large basal forebrain lesions were behaviorally unresponsive, had a monotonous sub-1 Hz EEG, and little cortical c-Fos expression during continuous gentle handling. We then retrogradely labeled inputs to the basal forebrain from the upper brainstem, and found a substantial input from glutamatergic neurons in the parabrachial nucleus and adjacent pre-coeruleus area. Cell specific lesions of the parabrachial-precoeruleus complex produced behavioral unresponsiveness, a monotonous sub-1Hz cortical EEG, and loss of cortical c-Fos expression during gentle handling. These experiments indicate that in rats the reticulo-thalamo-cortical pathway may play a very limited role in behavioral or electrocortical arousal, while the projection from the parabrachial nucleus and precoeruleus region, relayed by the basal forebrain to the cerebral cortex, may be critical for this process. PMID:21280045
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Depboylu, Candan; Weihe, Eberhard; Eiden, Lee E.
2011-01-01
The simian immunodeficiency virus (SIV) macaque model resembles human HIV-AIDS and associated brain dysfunction. Altered expression of synaptic markers and transmitters in neuro-AIDS has been reported, but limited data exist for the cholinergic system and lipid mediators such as prostaglandins. Here, we analyzed cholinergic basal forebrain neurons with their telencephalic projections and the rate-limiting enzymes for prostaglandin synthesis, cyclooxygenases 1 and 2 (COX1 and 2) in brains of SIV-infected macaques with and without encephalitis and antiretroviral therapy, and uninfected controls. COX1 but not COX2 was co-expressed with markers of cholinergic phenotype, i.e. choline acetyltransferase and vesicular acetylcholine transporter (VAChT), in basal forebrain neurons of monkey, as well as human samples. COX1 was decreased in basal forebrain neurons in macaques with AIDS vs. uninfected and asymptomatic SIV-infected macaques. VAChT-positive fiber density was reduced in frontal, parietal and hippocampal-entorhinal cortex. Although brain SIV burden and associated COX1- and COX2-positive mononuclear and endothelial inflammatory reactions were mostly reversed in AIDS-diseased macaques that received 6-chloro-2′,3′-dideoxyguanosine treatment, decreased VAChT-positive terminal density and reduced cholinergic COX1 expression were not. Thus, COX1 expression is a feature of primate cholinergic basal forebrain neurons; it may be functionally important and a critical biomarker of cholinergic dysregulation accompanying lentiviral encephalopathy. These results imply that insufficiently prompt initiation of antiretroviral therapy in lentiviral infection may lead to neurostructurally unremarkable but neurochemically prominent, irreversible brain damage. PMID:22157616
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Fineberg, Jeffrey D; Ritter, David M; Covarrubias, Manuel
2012-11-01
A-type voltage-gated K(+) (Kv) channels self-regulate their activity by inactivating directly from the open state (open-state inactivation [OSI]) or by inactivating before they open (closed-state inactivation [CSI]). To determine the inactivation pathways, it is often necessary to apply several pulse protocols, pore blockers, single-channel recording, and kinetic modeling. However, intrinsic hurdles may preclude the standardized application of these methods. Here, we implemented a simple method inspired by earlier studies of Na(+) channels to analyze macroscopic inactivation and conclusively deduce the pathways of inactivation of recombinant and native A-type Kv channels. We investigated two distinct A-type Kv channels expressed heterologously (Kv3.4 and Kv4.2 with accessory subunits) and their native counterparts in dorsal root ganglion and cerebellar granule neurons. This approach applies two conventional pulse protocols to examine inactivation induced by (a) a simple step (single-pulse inactivation) and (b) a conditioning step (double-pulse inactivation). Consistent with OSI, the rate of Kv3.4 inactivation (i.e., the negative first derivative of double-pulse inactivation) precisely superimposes on the profile of the Kv3.4 current evoked by a single pulse because the channels must open to inactivate. In contrast, the rate of Kv4.2 inactivation is asynchronous, already changing at earlier times relative to the profile of the Kv4.2 current evoked by a single pulse. Thus, Kv4.2 inactivation occurs uncoupled from channel opening, indicating CSI. Furthermore, the inactivation time constant versus voltage relation of Kv3.4 decreases monotonically with depolarization and levels off, whereas that of Kv4.2 exhibits a J-shape profile. We also manipulated the inactivation phenotype by changing the subunit composition and show how CSI and CSI combined with OSI might affect spiking properties in a full computational model of the hippocampal CA1 neuron. This work unambiguously elucidates contrasting inactivation pathways in neuronal A-type Kv channels and demonstrates how distinct pathways might impact neurophysiological activity.
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Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Elliott, L.H.; McCormick, J.B.; Johnson, K.M.
1982-10-01
Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with /sup 60/Co gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of /sup 60/Co radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose permore » rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. We found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents.« less
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Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation
DOE Office of Scientific and Technical Information (OSTI.GOV)
Elliott, L.H.; McCormick, J.B.; Johnson, K.M.
1982-10-01
Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with /sup 60/CO gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of /sup 60/CO radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose permore » rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. The authors found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents.« less
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Ouchi, Y; Kakiuchi, T; Okada, H; Nishiyama, S; Tsukada, H
1999-03-15
To evaluate the effect of aniracetam, a potent modulator of the glutamatergic and cholinergic systems, on the altered cerebral glucose metabolism after lesioning of the basal forebrain, we measured the cerebral metabolic rate of glucose (CMRGlc) with positron emission tomography and the choline acetyltransferase (ChAT) activity in the frontal cortex of the lesioned rats after treating them with aniracetam. Continuous administration of aniracetam for 7 days after the surgery prevented CMRGlc reduction in the frontal cortex ipsilateral to the lesion while the lesioned rats without aniracetam showed significant CMRGlc reduction in the frontal cortex. The level of CMRGlc in the lesion-side basal forebrain was lower in all rats regardless of the aniracetam treatment. Biochemical studies showed that aniracetam did not alter the reduction in the frontal ChAT activity. These results showed that aniracetam prevents glucose metabolic reduction in the cholinergically denervated frontal cortex with little effect on the cortical cholinergic system. The present study suggested that a neurotransmitter system other than the cholinergic system, e.g. the glutamatergic system, plays a central role in the cortical metabolic recovery after lesioning of the basal forebrain.
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Forebrain neuroanatomy of the neonatal and juvenile dolphin (T. truncatus and S. coeruloalba)
Parolisi, Roberta; Peruffo, Antonella; Messina, Silvia; Panin, Mattia; Montelli, Stefano; Giurisato, Maristella; Cozzi, Bruno; Bonfanti, Luca
2015-01-01
Knowledge of dolphin functional neuroanatomy mostly derives from post-mortem studies and non-invasive approaches (i.e., magnetic resonance imaging), due to limitations in experimentation on cetaceans. As a consequence the availability of well-preserved tissues for histology is scarce, and detailed histological analyses are referred mainly to adults. Here we studied the neonatal/juvenile brain in two species of dolphins, the bottlenose dolphin (Tursiops truncatus) and the striped dolphin (Stenella coeruleoalba), with special reference to forebrain regions. We analyzed cell density in subcortical nuclei, white/gray matter ratio, and myelination in selected regions at different anterior–posterior levels of the whole dolphin brain at different ages, to better define forebrain neuroanatomy and the developmental stage of the dolphin brain around birth. The analyses were extended to the periventricular germinal layer and the cerebellum, whose delayed genesis of the granule cell layer is a hallmark of postnatal development in the mammalian nervous system. Our results establish an atlas of the young dolphin forebrain and, on the basis of occurrence/absence of delayed neurogenic layers, confirm the stage of advanced brain maturation in these animals with respect to most terrestrial mammals. PMID:26594155
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Espinosa-Raya, Judith; Plata-Cruz, Noemí; Neri-Gómez, Teresa; Camacho-Arroyo, Ignacio; Picazo, Ofir
2011-02-23
It has been proposed that sex steroid hormones improve performance in some cognitive tasks by regulating the basal forebrain cholinergic function. However, the molecular basis of such influence still remains unknown. Current study analyzed the performance of ovariectomized rats in an autoshaping learning task after a short-term treatment with 17β-estradiol (E2: 4 and 40μg/kg) and/or progesterone (P4: 4mg/kg). These results were correlated with basal forebrain choline acetyltransferase (ChAT) and TrkA protein content. The high dose of E2 enhanced both acquisition in the autoshaping task and the content of ChAT and TrkA. P4 treatment increased ChAT and TrkA content without affecting performance of rats in the autoshaping learning task. Interestingly, the continuous and simultaneous administration of E2 plus P4 did not significantly modify behavioral and biochemical evaluated parameters. These results address the influence of both E2 and P4 on cholinergic and TrkA activity and suggest that the effects of ovarian hormones on cognitive performance involve basal forebrain cholinergic neurons. Copyright © 2010 Elsevier B.V. All rights reserved.
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Garcia-Alvarez, Gisela; Shetty, Mahesh S.; Lu, Bo; Yap, Kenrick An Fu; Oh-Hora, Masatsugu; Sajikumar, Sreedharan; Bichler, Zoë; Fivaz, Marc
2015-01-01
Recent findings point to a central role of the endoplasmic reticulum-resident STIM (Stromal Interaction Molecule) proteins in shaping the structure and function of excitatory synapses in the mammalian brain. The impact of the Stim genes on cognitive functions remains, however, poorly understood. To explore the function of the Stim genes in learning and memory, we generated three mouse strains with conditional deletion (cKO) of Stim1 and/or Stim2 in the forebrain. Stim1, Stim2, and double Stim1/Stim2 cKO mice show no obvious brain structural defects or locomotor impairment. Analysis of spatial reference memory in the Morris water maze revealed a mild learning delay in Stim1 cKO mice, while learning and memory in Stim2 cKO mice was indistinguishable from their control littermates. Deletion of both Stim genes in the forebrain resulted, however, in a pronounced impairment in spatial learning and memory reflecting a synergistic effect of the Stim genes on the underlying neural circuits. Notably, long-term potentiation (LTP) at CA3-CA1 hippocampal synapses was markedly enhanced in Stim1/Stim2 cKO mice and was associated with increased phosphorylation of the AMPA receptor subunit GluA1, the transcriptional regulator CREB and the L-type Voltage-dependent Ca2+ channel Cav1.2 on protein kinase A (PKA) sites. We conclude that STIM1 and STIM2 are key regulators of PKA signaling and synaptic plasticity in neural circuits encoding spatial memory. Our findings also reveal an inverse correlation between LTP and spatial learning/memory and suggest that abnormal enhancement of cAMP/PKA signaling and synaptic efficacy disrupts the formation of new memories. PMID:26236206
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NASA Technical Reports Server (NTRS)
Sajdel-Sulkowska, E. M.; Li, G. H.; Ronca, A. E.; Baer, L. A.; Sulkowski, G. M.; Koibuchi, N.; Wade, C. E.
2001-01-01
The present study examined the effects of hypergravity exposure on the developing brain and specifically explored the possibility that these effects are mediated by altered thyroid status. Thirty-four timed-pregnant Sprague-Dawley rats were exposed to continuous centrifugation at 1.5 G (HG) from gestational Day 11 until one of three key developmental points: postnatal Day (P) 6, P15, or P21 (10 pups/dam: 5 males/5 females). During the 32-day centrifugation, stationary controls (SC, n = 25 dams) were housed in the same room as HG animals. Neonatal body, forebrain, and cerebellum mass and neonatal and maternal thyroid status were assessed at each time point. The body mass of centrifuged neonates was comparatively lower at each time point. The mass of the forebrain and the mass of the cerebellum were maximally reduced in hypergravity-exposed neonates at P6 by 15.9% and 25.6%, respectively. Analysis of neonatal plasma suggested a transient hypothyroid status, as indicated by increased thyroid stimulating hormone (TSH) level (38.6%) at P6, while maternal plasma TSH levels were maximally elevated at P15 (38.9%). Neither neonatal nor maternal plasma TH levels were altered, suggesting a moderate hypothyroid condition. Thus, continuous exposure of the developing rats to hypergravity during the embryonic and neonatal periods has a highly significant effect on the developing forebrain and cerebellum and neonatal thyroid status (P < 0.05, Bonferroni corrected). These data are consistent with the hypothesized role of the thyroid hormone in mediating the effect of hypergravity in the developing central nervous system and begin to define the role of TH in the overall response of the developing organism to altered gravity.
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A novel anxiogenic role for the delta opioid receptor expressed in GABAergic forebrain neurons
Chung, Paul Chu Sin; Keyworth, Helen L.; Martin-Garcia, Elena; Charbogne, Pauline; Darcq, Emmanuel; Bailey, Alexis; Filliol, Dominique; Matifas, Audrey; Ouagazzal, Abdel-Mouttalib; Gaveriaux-Ruff, Claire; Befort, Katia; Maldonado, Rafael; Kitchen, Ian; Kieffer, Brigitte L.
2014-01-01
Background The delta opioid receptor (DOR) is broadly expressed throughout the nervous system and regulates chronic pain, emotional responses, motivation and memory. Neural circuits underlying DOR activities have been poorly explored by genetic approaches. Here we used conditional mouse mutagenesis to elucidate receptor function in GABAergic neurons of the forebrain. Methods We characterized DOR distribution in the brain of Dlx5/6-CreXOprd1fl/fl (Dlx-DOR) mice, and tested main central DOR functions through behavioral testing. Results DORs proteins were strongly deleted in olfactory bulb and striatum, and remained intact in cortex and basolateral amygdala. Olfactory perception, circadian activity and despair-like behaviors were unchanged. In contrast, locomotor stimulant effects of SNC80 (DOR agonist) and SKF81297 (D1 agonist) were abolished and increased, respectively. Furthermore, Dlx-DOR mice showed lower levels of anxiety in the elevated plus-maze, opposing the known high anxiety in constitutive DOR knockout animals. Also Dlx-DOR mice reached the food more rapidly in a novelty suppressed feeding (NSF) task, despite their lower motivation for food reward observed in an operant paradigm. Finally, c-fos staining after NSF was strongly reduced in amygdala, concordant with the low anxiety phenotype of Dlx-DOR mice. Conclusion Here we demonstrate that DORs expressed in the forebrain mediate the described locomotor effect of SNC80 and inhibit D1-stimulated hyperactivity. Our data also reveal an unanticipated anxiogenic role for this particular DOR subpopulation, with a potential novel adaptive role. DORs therefore exert dual anxiolytic/anxiogenic roles in emotional responses, which may both have implications in the area of anxiety disorders. PMID:25444168
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Inactivation of MS2 bacteriophage by streamer corona discharge in water.
Lee, Changha; Kim, Jaeeun; Yoon, Jeyong
2011-02-01
Electrical discharge processes are emerging as water treatment technologies applicable to both the degradation of organic contaminants as well as inactivation of pathogens. Particularly as a disinfection technology, electrical discharge processes do not produce toxic byproducts, and effectively inactivate a wide spectrum of microorganisms by multiple lethal actions generated by the formation of plasma channels. This study demonstrates the inactivation of a virus using the streamer corona discharge process (SCDP) with MS2 phage as a surrogate. A rapid inactivation of MS2 phage (i.e., approximately 4 log inactivation in 5 min) was observed in all experimental runs conducted. Discharge conditions such as applied voltage and storage capacitance significantly affected the inactivation efficiency of MS2 phage, whereas the influence of water quality parameters was minor. In order to elucidate the mechanism of MS2 phage inactivation, potentially lethal factors that can be generated by the SCDP were selected, and their roles in the inactivation of MS2 phage were examined. As a result, effects of UV radiation, chemical oxidants, and pulsed electric fields were found to be insignificant. The shockwave generated upon plasma channel formation appears to be the most important factor responsible for MS2 phage inactivation. Copyright © 2010 Elsevier Ltd. All rights reserved.
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Sunlight inactivation of somatic coliphage in the presence of natural organic matter.
Sun, Chen-Xi; Kitajima, Masaaki; Gin, Karina Yew-Hoong
2016-01-15
Long wavelengths of sunlight spectrum (UVA and visible light), as well as natural organic matter (NOM) are important environmental factors affecting survival of viruses in aquatic environment through direct and indirect inactivation. In order to understand the virus inactivation kinetics under such conditions, this study investigated the effects of Suwannee River natural organic matter (NOM) on the inactivation of a somatic coliphage, phiX174, by UVA and visible light. Experiments were carried out to examine the virucidal effects of UVA/visible light, assess the influence of SRNOM at different concentrations, and identify the effective ROS in virus inactivation. The results from this study showed that the presence of NOM could either enhance virus inactivation or reduce virus inactivation depending on the concentration, where the inactivation rate followed a parabolic relationship against NOM concentration. The results indicated that moderate levels of NOM (11 ppm) had the strongest antiviral activity, while very low or very high NOM concentrations prolonged virus survival. The results also showed that OH▪ was the primary ROS in causing phiX174 (ssDNA virus) inactivation, unlike previous findings where (1)O2 was the primary ROS causing MS2 (ssRNA virus) inactivation. The phiX174 inactivation by OH∙ could be described as k=3.7 ✕ 10(13)[OH∙]+1.404 (R(2)=0.8527). Copyright © 2015 Elsevier B.V. All rights reserved.
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Cao, Hong; Saraf, Amit; Zweifel, Larry S.
2015-01-01
The type 1 adenylyl cyclase (AC1) is an activity-dependent, calcium-stimulated adenylyl cyclase expressed in the nervous system that is implicated in memory formation. We examined the locomotor activity, and impulsive and social behaviors of AC1+ mice, a transgenic mouse strain overexpressing AC1 in the forebrain. Here we report that AC1+ mice exhibit hyperactive behaviors and demonstrate increased impulsivity and reduced sociability. In contrast, AC1 and AC8 double knock-out mice are hypoactive, and exhibit increased sociability and reduced impulsivity. Interestingly, the hyperactivity of AC1+ mice can be corrected by valproate, a mood-stabilizing drug. These data indicate that increased expression of AC1 in the forebrain leads to deficits in behavioral inhibition. PMID:25568126
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Temporal variations in early developmental decisions: an engine of forebrain evolution.
Bielen, H; Pal, S; Tole, S; Houart, C
2017-02-01
Tight control of developmental timing is pivotal to many major processes in developmental biology, such as patterning, fate specification, cell cycle dynamics, cell migration and connectivity. Temporal change in these ontogenetic sequences is known as heterochrony, a major force in the evolution of body plans and organogenesis. In the last 5 years, studies in fish and rodents indicate that heterochrony in signaling during early development generates diversity in forebrain size and complexity. Here, we summarize these findings and propose that, additionally to spatio-temporal tuning of neurogenesis, temporal and quantitative modulation of signaling events drive pivotal changes in shape, size and complexity of the forebrain across evolution, participating to the generation of diversity in animal behavior and emergence of cognition. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Zhu, Anna; Liu, Harris K; Long, Feng; Su, Erzheng; Klibanov, Alexander M
2015-01-01
Uniform conductive composite membranes were prepared using a phase inversion method by blending carboxyl-functionalized multi-walled carbon nanotubes (CNTs) with a polysulfone polymer. At 6 % of the embedded CNTs, the membrane pore size measured by transmission electron microscopy (TEM) was approximately 50 nm. Electric current in the presence of the composite membranes markedly inactivated the model pathogenic bacteria Escherichia coli and Staphylococcus aureus, with the extent of bacterial inactivation rising when the current was increased. Over 99.999 % inactivation of both bacteria was observed in deionized water after 40 min at 5 mA direct current (DC); importantly, no appreciable inactivation occurred in the absence of either the electric field or the CNTs within the membranes under otherwise the same conditions. A much lower, although still pronounced, inactivation was seen with alternating current (AC) in a 25 mM NaCl aqueous solution.
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Infective and inactivated filamentous phage as carriers for immunogenic peptides.
Samoylova, Tatiana I; Norris, Mandy D; Samoylov, Alexandre M; Cochran, Anna M; Wolfe, Karen G; Petrenko, Valery A; Cox, Nancy R
2012-07-01
The focus of this study is on development of vaccines using filamentous phage as a delivery vector for immunogenic peptides. The use of phage as a carrier for immunogenic peptides provides significant benefits such as high immunogenicity, low production costs, and high stability of phage preparations. However, introduction of live recombinant phage into the environment might represent a potential ecological problem. This, for example, may occur when vaccines are used in oral or nasal formulations in field conditions for wild and feral animals. To address this issue, comparative studies of antigenic properties of live and inactivated (non-viable) phage were accomplished. Inactivated phage, if released, will not propagate and will degrade as any other protein. In these experiments, a model phage clone that was previously selected from a phage display library and shown to stimulate production of anti-sperm antibodies with contraceptive properties was used. Multiple methods of phage inactivation were tested, including drying, freezing, autoclaving, heating, and UV irradiation. Under studied conditions, heating at 76°C for 3h, UV irradiation, and autoclaving resulted in complete phage inactivation. Phage samples treated by heat and UV were characterized by spectrophotometry and electron microscopy. To test antigenicity, live and inactivated phage preparations were injected into mice and antibody responses assayed by ELISA. It was found that phage killed by heat causes little to no immune responses, probably due to destruction of phage particles. In contrast, UV-inactivated phage stimulated production of IgG serum antibodies at the levels comparable to live phage. Thus, vaccines formulated to include UV-inactivated filamentous phage might represent environmentally safe alternatives to live phage vaccines. Copyright © 2012 Elsevier B.V. All rights reserved.
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Yong, Hae In; Kim, Hyun-Joo; Park, Sanghoo; Choe, Wonho; Oh, Mi Wha; Jo, Cheorun
2014-08-01
Atmospheric pressure plasma (APP) is an emerging nonthermal microbial inactivation technique. In this study, agar and raw chicken breast were inoculated with Escherichia coli and treated with an APP jet based on cold arc plasma. The aim of this study was to investigate the optimum conditions for the plasma treatment of an APP jet in order to maximize the efficiency of E. coli inactivation. The combination of N2+O2 (10 standard cubic centimeters per minute) and a longer treatment time (10 min) resulted in the highest inactivation of E. coli on agar plates with an optimum treatment distance of 20 mm. The samples in dry and wet conditions showed similar reductions in E. coli count when one side of the samples was treated at a given treatment time. Treating both sides-2.5 min on each side-resulted in a higher growth inhibition of E. coli than treatment of a single side only for 5 min. However, there was no significant difference between one-side treated samples (10 min) and both-sides treated samples (5+5 min). When the concentration of E. coli in the chicken breast sample was 10(4) colony-forming units (CFU)/g, the reduction rate of the E. coli was the highest, followed by 10(5), 10(6), and 10(7) CFU/g; however, no difference was found between 10(3) and 10(4) CFU/g. In conclusion, various treatment conditions may affect the inactivation efficiency of E. coli. In the present study, the optimum condition was determined as the treatment distance of 20 mm and longer treatment time (10 min) with the addition of oxygen to the nitrogen gas flow. Furthermore, the cell concentration of sample was an important parameter for the efficacy of the inactivation process.
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2012-01-01
Background Outbreaks of infectious diseases by microbial pathogens can cause substantial losses of stock in aquaculture systems. There are several ways to eliminate these pathogens including the use of antibiotics, biocides and conventional disinfectants, but these leave undesirable chemical residues. Conversely, using sunlight for disinfection has the advantage of leaving no chemical residue and is particularly suited to countries with sunny climates. Titanium dioxide (TiO2) is a photocatalyst that increases the effectiveness of solar disinfection. In recent years, several different types of solar photocatalytic reactors coated with TiO2 have been developed for waste water and drinking water treatment. In this study a thin-film fixed-bed reactor (TFFBR), designed as a sloping flat plate reactor coated with P25 DEGUSSA TiO2, was used. Results The level of inactivation of the aquaculture pathogen Aeromonas hydrophila ATCC 35654 was determined after travelling across the TFFBR under various natural sunlight conditions (300-1200 W m-2), at 3 different flow rates (4.8, 8.4 and 16.8 L h-1). Bacterial numbers were determined by conventional plate counting using selective agar media, cultured (i) under conventional aerobic conditions to detect healthy cells and (ii) under conditions designed to neutralise reactive oxygen species (agar medium supplemented with the peroxide scavenger sodium pyruvate at 0.05% w/v, incubated under anaerobic conditions), to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results clearly demonstrate that high sunlight intensities (≥ 600 W m-2) and low flow rates (4.8 L h-1) provided optimum conditions for inactivation of A. hydrophila ATCC 3564, with greater overall inactivation and fewer sub-lethally injured cells than at low sunlight intensities or high flow rates. Low sunlight intensities resulted in reduced overall inactivation and greater sub-lethal injury at all flow rates. Conclusions This is the first demonstration of the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila at high sunlight intensities, providing proof-of-concept for the application of solar photocatalysis in aquaculture systems. PMID:22243515
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Carr, Russell L.; Graves, Casey A.; Mangum, Lee C.; Nail, Carole A.; Ross, Matthew K.
2014-01-01
The prevailing dogma is that chlorpyrifos (CPF) mediates its toxicity through inhibition of cholinesterase (ChE). However, in recent years, the toxicological effects of developmental CPF exposure have been attributed to an unknown non-cholinergic mechanism of action. We hypothesize that the endocannabinoid system may be an important target because of its vital role in nervous system development. We have previously reported that repeated exposure to CPF results in greater inhibition of fatty acid amide hydrolase (FAAH), the enzyme that metabolizes the endocannabinoid anandamide (AEA), than inhibition of either forebrain ChE or monoacylglycerol lipase (MAGL), the enzyme that metabolizes the endocannabinoid 2-arachidonylglycerol (2-AG). This exposure resulted in the accumulation of 2-AG and AEA in the forebrain of juvenile rats; however, even at the lowest dosage level used (1.0 mg/kg), forebrain ChE inhibition was still present. Thus, it is not clear if FAAH activity would be inhibited at dosage levels that do not inhibit ChE. To determine this, 10 day old rat pups were exposed daily for 7 days to either corn oil or 0.5 mg/kg CPF by oral gavage. At 4 and 12 h post-exposure on the last day of administration, the activities of serum ChE and carboxylesterase (CES) and forebrain ChE, MAGL, and FAAH were determined as well as the forebrain AEA and 2-AG levels. Significant inhibition of serum ChE and CES was present at both 4 and 12 h. There was no significant inhibition of the activities of forebrain ChE or MAGL and no significant change in the amount of 2-AG at either time point. On the other hand, while no statistically significant effects were observed at 4 h, FAAH activity was significantly inhibited at 12 h resulting in a significant accumulation of AEA. Although it is not clear if this level of accumulation impacts brain maturation, this study demonstrates that developmental CPF exposure at a level that does not inhibit brain ChE can alter components of endocannabinoid signaling. PMID:24373905
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Zimmermann, Morgana; Longhi, Daniel A; Schaffner, Donald W; Aragão, Gláucia M F
2014-05-01
The knowledge and understanding of Bacillus coagulans inactivation during a thermal treatment in tomato pulp, as well as the influence of temperature variation during thermal processes are essential for design, calculation, and optimization of the process. The aims of this work were to predict B. coagulans spores inactivation in tomato pulp under varying time-temperature profiles with Gompertz-inspired inactivation model and to validate the model's predictions by comparing the predicted values with experimental data. B. coagulans spores in pH 4.3 tomato pulp at 4 °Brix were sealed in capillary glass tubes and heated in thermostatically controlled circulating oil baths. Seven different nonisothermal profiles in the range from 95 to 105 °C were studied. Predicted inactivation kinetics showed similar behavior to experimentally observed inactivation curves when the samples were exposed to temperatures in the upper range of this study (99 to 105 °C). Profiles that resulted in less accurate predictions were those where the range of temperatures analyzed were comparatively lower (inactivation profiles starting at 95 °C). The link between fail prediction and both lower starting temperature and magnitude of the temperature shift suggests some chemical or biological mechanism at work. Statistical analysis showed that overall model predictions were acceptable, with bias factors from 0.781 to 1.012, and accuracy factors from 1.049 to 1.351, and confirm that the models used were adequate to estimate B. coagulans spores inactivation under fluctuating temperature conditions in the range from 95 to 105 °C. How can we estimate Bacillus coagulans inactivation during sudden temperature shifts in heat processing? This article provides a validated model that can be used to predict B. coagulans under changing temperature conditions. B. coagulans is a spore-forming bacillus that spoils acidified food products. The mathematical model developed here can be used to predict the spoilage risk following thermal process deviations for tomato products. © 2014 Institute of Food Technologists®
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León, Manuel Ponce-De; Cabrera-Juárez, Emiliano
1970-01-01
The photodynamic inactivation of native or denatured transforming deoxyribonucleic acid (DNA) from Haemophilus influenzae is described. The inactivation at the same pH was higher for denatured than native DNA. At acidic pH, the inactivation both for native and denatured DNA was faster than at alkaline pH. The guanine content of photoinactivated native DNA at neutral pH was less than untreated DNA. The inactivation of biological activity was more extensive than the alteration of guanine. The absorption spectrum of photoinactivated native or denatured DNA was only slightly different than the control DNA at the different experimental conditions. PMID:5309576
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Navé, Jean-François; Benveniste, Pierre
1984-01-01
The specific binding of 1-[3H]naphthyl acetic acid (NAA) to membrane-bound binding sites from maize (Zea mays cv INRA 258) coleoptiles is inactivated by phenylglyoxal. The inactivation obeys pseudo first-order kinetics. The rate of inactivation is proportional to phenylglyoxal concentration. Under conditions at which significant binding occurs, NAA, R and S-1-naphthyl 2-propionic acids protect the auxin binding site against inactivation by phenylglyoxal. Scatchard analysis shows that the inhibition of binding corresponds to a decrease in the concentration of sites but not in the affinity. The results of the present chemical modification study indicate that at least one arginyl residue is involved in the positively charged recognition site of the carboxylate anion of NAA. PMID:16663499
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Mishra, Nibha; Milikovsky, Dan Z.; Hanin, Geula; Zelig, Daniel; Sheintuch, Liron; Berson, Amit; Greenberg, David S.; Friedman, Alon
2017-01-01
Epilepsy is a common neurological disease, manifested in unprovoked recurrent seizures. Epileptogenesis may develop due to genetic or pharmacological origins or following injury, but it remains unclear how the unaffected brain escapes this susceptibility to seizures. Here, we report that dynamic changes in forebrain microRNA (miR)-211 in the mouse brain shift the threshold for spontaneous and pharmacologically induced seizures alongside changes in the cholinergic pathway genes, implicating this miR in the avoidance of seizures. We identified miR-211 as a putative attenuator of cholinergic-mediated seizures by intersecting forebrain miR profiles that were Argonaute precipitated, synaptic vesicle target enriched, or differentially expressed under pilocarpine-induced seizures, and validated TGFBR2 and the nicotinic antiinflammatory acetylcholine receptor nAChRa7 as murine and human miR-211 targets, respectively. To explore the link between miR-211 and epilepsy, we engineered dTg-211 mice with doxycycline-suppressible forebrain overexpression of miR-211. These mice reacted to doxycycline exposure by spontaneous electrocorticography-documented nonconvulsive seizures, accompanied by forebrain accumulation of the convulsive seizures mediating miR-134. RNA sequencing demonstrated in doxycycline-treated dTg-211 cortices overrepresentation of synaptic activity, Ca2+ transmembrane transport, TGFBR2 signaling, and cholinergic synapse pathways. Additionally, a cholinergic dysregulated mouse model overexpressing a miR refractory acetylcholinesterase-R splice variant showed a parallel propensity for convulsions, miR-211 decreases, and miR-134 elevation. Our findings demonstrate that in mice, dynamic miR-211 decreases induce hypersynchronization and nonconvulsive and convulsive seizures, accompanied by expression changes in cholinergic and TGFBR2 pathways as well as in miR-134. Realizing the importance of miR-211 dynamics opens new venues for translational diagnosis of and interference with epilepsy. PMID:28584127
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Parreira, Gabriela Machado; Resende, Maria Daniela Aparecida; Garcia, Israel José Pereira; Sartori, Daniela Bueno; Umeoka, Eduardo Henrique de Lima; Godoy, Lívea Dornela; Garcia-Cairasco, Norberto; Barbosa, Leandro Augusto; Santos, Hérica de Lima; Tilelli, Cristiane Queixa
2018-01-15
The Wistar Audiogenic Rat (WAR) is a well-characterized seizure-prone, inbred rodent strain that, when acutely stimulated with high-intensity sounds, develops brainstem-dependent tonic-clonic seizures that can evolve to limbic-like, myoclonic (forebrain) seizures when the acoustic stimuli are presented chronically (audiogenic kindling). In order to investigate possible mechanisms underlying WAR susceptibility to seizures, we evaluated Na,K-ATPase activity, Ca-ATPase activity, Mg-ATPase activity, lipid membrane composition and oxidative stress markers in whole forebrain and whole brainstem samples of naïve WAR, as compared to samples from control Wistar rats. We also evaluated the expression levels of α1 and α3 isoforms of Na,K-ATPase in forebrain samples. We observed increased Na,K-ATPase activity in forebrain samples and increased oxidative stress markers (lipid peroxidation, glutathione peroxidase and superoxide dismutase) in brainstem samples of WAR. The Ca-ATPase activity, Mg-ATPase activity, lipid membrane composition and expression levels of α1 and α3 isoforms of Na,K-ATPase were unaltered. In view of previous data showing that the membrane potentials from naïve WAR's neurons are less negative than that from neurons from Wistar rats, we suggest that Na,K-ATPase increased activity might be involved in a compensatory mechanism necessary to maintain WAR's brains normal activity. Additionally, ongoing oxidative stress in the brainstem could bring Na,K-ATPase activity back to normal levels, which may explain why WAR's present increased susceptibility to seizures triggered by high-intensity sound stimulation. Copyright © 2017 Elsevier B.V. All rights reserved.
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Bekenstein, Uriya; Mishra, Nibha; Milikovsky, Dan Z; Hanin, Geula; Zelig, Daniel; Sheintuch, Liron; Berson, Amit; Greenberg, David S; Friedman, Alon; Soreq, Hermona
2017-06-20
Epilepsy is a common neurological disease, manifested in unprovoked recurrent seizures. Epileptogenesis may develop due to genetic or pharmacological origins or following injury, but it remains unclear how the unaffected brain escapes this susceptibility to seizures. Here, we report that dynamic changes in forebrain microRNA (miR)-211 in the mouse brain shift the threshold for spontaneous and pharmacologically induced seizures alongside changes in the cholinergic pathway genes, implicating this miR in the avoidance of seizures. We identified miR-211 as a putative attenuator of cholinergic-mediated seizures by intersecting forebrain miR profiles that were Argonaute precipitated, synaptic vesicle target enriched, or differentially expressed under pilocarpine-induced seizures, and validated TGFBR2 and the nicotinic antiinflammatory acetylcholine receptor nAChRa7 as murine and human miR-211 targets, respectively. To explore the link between miR-211 and epilepsy, we engineered dTg-211 mice with doxycycline-suppressible forebrain overexpression of miR-211. These mice reacted to doxycycline exposure by spontaneous electrocorticography-documented nonconvulsive seizures, accompanied by forebrain accumulation of the convulsive seizures mediating miR-134. RNA sequencing demonstrated in doxycycline-treated dTg-211 cortices overrepresentation of synaptic activity, Ca 2+ transmembrane transport, TGFBR2 signaling, and cholinergic synapse pathways. Additionally, a cholinergic dysregulated mouse model overexpressing a miR refractory acetylcholinesterase-R splice variant showed a parallel propensity for convulsions, miR-211 decreases, and miR-134 elevation. Our findings demonstrate that in mice, dynamic miR-211 decreases induce hypersynchronization and nonconvulsive and convulsive seizures, accompanied by expression changes in cholinergic and TGFBR2 pathways as well as in miR-134. Realizing the importance of miR-211 dynamics opens new venues for translational diagnosis of and interference with epilepsy.
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Genestine, Matthieu; Lin, Lulu; Durens, Madel; Yan, Yan; Jiang, Yiqin; Prem, Smrithi; Bailoor, Kunal; Kelly, Brian; Sonsalla, Patricia K.; Matteson, Paul G.; Silverman, Jill; Crawley, Jacqueline N.; Millonig, James H.; DiCicco-Bloom, Emanuel
2015-01-01
Many genes involved in brain development have been associated with human neurodevelopmental disorders, but underlying pathophysiological mechanisms remain undefined. Human genetic and mouse behavioral analyses suggest that ENGRAILED-2 (EN2) contributes to neurodevelopmental disorders, especially autism spectrum disorder. In mouse, En2 exhibits dynamic spatiotemporal expression in embryonic mid-hindbrain regions where monoamine neurons emerge. Considering their importance in neuropsychiatric disorders, we characterized monoamine systems in relation to forebrain neurogenesis in En2-knockout (En2-KO) mice. Transmitter levels of serotonin, dopamine and norepinephrine (NE) were dysregulated from Postnatal day 7 (P7) to P21 in En2-KO, though NE exhibited the greatest abnormalities. While NE levels were reduced ∼35% in forebrain, they were increased 40–75% in hindbrain and cerebellum, and these patterns paralleled changes in locus coeruleus (LC) fiber innervation, respectively. Although En2 promoter was active in Embryonic day 14.5–15.5 LC neurons, expression diminished thereafter and gene deletion did not alter brainstem NE neuron numbers. Significantly, in parallel with reduced NE levels, En2-KO forebrain regions exhibited reduced growth, particularly hippocampus, where P21 dentate gyrus granule neurons were decreased 16%, suggesting abnormal neurogenesis. Indeed, hippocampal neurogenic regions showed increased cell death (+77%) and unexpectedly, increased proliferation. Excess proliferation was restricted to early Sox2/Tbr2 progenitors whereas increased apoptosis occurred in differentiating (Dcx) neuroblasts, accompanied by reduced newborn neuron survival. Abnormal neurogenesis may reflect NE deficits because intra-hippocampal injections of β-adrenergic agonists reversed cell death. These studies suggest that disruption of hindbrain patterning genes can alter monoamine system development and thereby produce forebrain defects that are relevant to human neurodevelopmental disorders. PMID:26220976
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Depboylu, Candan; Weihe, Eberhard; Eiden, Lee E
2012-01-01
The simian immunodeficiency virus (SIV) macaque model resembles human immunodeficiency virus-acquired immunodeficiency syndrome (AIDS) and associated brain dysfunction. Altered expression of synaptic markers and transmitters in neuro-AIDS has been reported, but limited data exist for the cholinergic system and lipid mediators such as prostaglandins. Here, we analyzed cholinergic basal forebrain neurons with their telencephalic projections and the rate-limiting enzymes for prostaglandin synthesis, cyclooxygenase isotypes 1 and 2 (COX1 and COX2) in the brains of SIV-infected macaques with or without encephalitis and antiretroviral therapy and uninfected controls.Cyclooxygenase isotype 1, but not COX2, was coexpressed with markers of cholinergic phenotype, that is, choline acetyltransferase and vesicular acetylcholine transporter (VAChT), in basal forebrain neurons of monkey, as well as human, brain. Cyclooxygenase isotype 1 was decreased in basal forebrain neurons in macaques with AIDS versus uninfected and asymptomatic SIV-infected macaques. The VAChT-positive fiber density was reduced in frontal, parietal, and hippocampal-entorhinal cortex. Although brain SIV burden and associated COX1- and COX2-positive mononuclear and endothelial inflammatory reactions were mostly reversed in AIDS-diseased macaques that received 6-chloro-2',3'-dideoxyguanosine treatment, decreased VAChT-positive terminal density and reduced cholinergic COX1 expression were not. Thus, COX1 expression is a feature of primate cholinergic basal forebrain neurons; it may be functionally important and a critical biomarker of cholinergic dysregulation accompanying lentiviral encephalopathy. These results further imply that insufficiently prompt initiation of antiretroviral therapy in lentiviral infection may lead to neurostructurally unremarkable but neurochemically prominent irreversible brain damage.
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Fee, Michale S.
2011-01-01
Learned motor behaviors require descending forebrain control to be coordinated with midbrain and brainstem motor systems. In songbirds, such as the zebra finch, regular breathing is controlled by brainstem centers, but when the adult songbird begins to sing, its breathing becomes tightly coordinated with forebrain-controlled vocalizations. The periods of silence (gaps) between song syllables are typically filled with brief breaths, allowing the bird to sing uninterrupted for many seconds. While substantial progress has been made in identifying the brain areas and pathways involved in vocal and respiratory control, it is not understood how respiratory and vocal control is coordinated by forebrain motor circuits. Here we combine a recently developed technique for localized brain cooling, together with recordings of thoracic air sac pressure, to examine the role of cortical premotor nucleus HVC (proper name) in respiratory-vocal coordination. We found that HVC cooling, in addition to slowing all song timescales as previously reported, also increased the duration of expiratory pulses (EPs) and inspiratory pulses (IPs). Expiratory pulses, like song syllables, were stretched uniformly by HVC cooling, but most inspiratory pulses exhibited non-uniform stretch of pressure waveform such that the majority of stretch occurred late in the IP. Indeed, some IPs appeared to change duration by the earlier or later truncation of an underlying inspiratory event. These findings are consistent with the idea that during singing the temporal structure of EPs is under the direct control of forebrain circuits, whereas that of IPs can be strongly influenced by circuits downstream of HVC, likely in the brainstem. An analysis of the temporal jitter of respiratory and vocal structure suggests that IPs may be initiated by HVC at the end of each syllable and terminated by HVC immediately before the onset of the next syllable. PMID:21980466
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Kim, Hyung-Eun; Nguyen, Thuy T M; Lee, Hongshin; Lee, Changha
2015-12-15
The inactivation of Escherichia coli and MS2 coliphage by Cu(II) is found to be significantly enhanced in the presence of hydroxylamine (HA). The addition of a small amount of HA (i.e., 5-20 μM) increased the inactivation efficacies of E. coli and MS2 coliphage by 5- to 100-fold, depending on the conditions. Dual effects were anticipated to enhance the biocidal activity of Cu(II) by the addition of HA, viz. (i) the accelerated reduction of Cu(II) into Cu(I) (a stronger biocide) and (ii) the production of reactive oxidants from the reaction of Cu(I) with dissolved oxygen (evidenced by the oxidative transformation of methanol into formaldehyde). Deaeration enhanced the inactivation of E. coli but slightly decreased the inactivation efficacy of MS2 coliphage. The addition of 10 μM hydrogen peroxide (H2O2) greatly enhanced the MS2 inactivation, whereas the same concentration of H2O2 did not significantly affect the inactivation efficacy of E. coli Observations collectively indicate that different biocidal actions lead to the inactivation of E. coli and MS2 coliphage. The toxicity of Cu(I) is dominantly responsible for the E. coli inactivation. However, for the MS2 coliphage inactivation, the oxidative damage induced by reactive oxidants is as important as the effect of Cu(I).
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MS2 inactivation by TiO2 nanoparticles in the presence of quartz sand
NASA Astrophysics Data System (ADS)
Syngouna, Vasiliki I.; Chrysikopoulos, Constantinos V.
2017-04-01
Virus inactivation by nanoparticles (NPs) is hypothesized to affect virus fate and transport in the subsurface. This study examines the interactions of viruses with titanium dioxide (TiO2) anatase NPs, which is a good disinfectant with unique physiochemical properties, using three different virus concentrations. The bacteriophage MS2 was used as a model virus. A series of batch experiments of MS2 inactivation by TiO2 NPs were conducted at room temperature (25 °C), in the presence of quartz sand, with and without ambient light. The virus inactivation experimental data were satisfactorily fitted with a pseudo-first order expression with a time dependent rate coefficient. Quartz sand was shown to affect MS2 inactivation by TiO2 NPs both in the presence and absence of ambient light, because, under the experimental conditions of this study, the quartz sand offers a protection to the attached MS2 against inactivation. Moreover, in most cases similar inactivation rates were observed in reactor and control tubes (absence of TiO2 NPs) suggesting that low TiO2 concentration (10 mg/L) affects only slightly MS2 inactivation with and without ambient light.
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Qualitation and Quantitation on Microplasma Jet for Bacteria Inactivation.
Du, ChangMing; Liu, Ya; Huang, YaNi; Li, ZiMing; Men, Rui; Men, Yue; Tang, Jun
2016-01-06
In this work, a self-made microplasma jet system was used to conduct the qualitation and quantitation of inactivation with Escherichia coli as the target bacteria. The logarithmic concentration and the size of antimicrobial rings served as the evaluation parameters, respectively. The effect of various parameters on inactivation effect was studied. The results showed that the majority of bacteria had been inactivated in 30 s. The inactivation effect enhanced and then weakened with the increase of air flow rate, and receded as the extension of treatment distance. The effect with different carrier gases showed as follows: oxygen > air > nitrogen > argon. Meanwhile, the effect of different components of microplasma was studied in the optimum conditions (The flow rate was 5 L/min; inactivation distance was 2 cm). The results showed that electrically neutral active species was the main factor of inactivation rather than heating effect, ultraviolet radiation and charged particles. Finally the experiments of thallus change proved that microplasma jet had etching effect on cell membrane. It also found that microplasma could degrade organic material like protein. Furthermore, the images of scanning electron microscope (SEM) revealed the change of cell morphology step by step in the whole process of inactivation.
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Qualitation and Quantitation on Microplasma Jet for Bacteria Inactivation
NASA Astrophysics Data System (ADS)
Du, Changming; Liu, Ya; Huang, Yani; Li, Ziming; Men, Rui; Men, Yue; Tang, Jun
2016-01-01
In this work, a self-made microplasma jet system was used to conduct the qualitation and quantitation of inactivation with Escherichia coli as the target bacteria. The logarithmic concentration and the size of antimicrobial rings served as the evaluation parameters, respectively. The effect of various parameters on inactivation effect was studied. The results showed that the majority of bacteria had been inactivated in 30 s. The inactivation effect enhanced and then weakened with the increase of air flow rate, and receded as the extension of treatment distance. The effect with different carrier gases showed as follows: oxygen > air > nitrogen > argon. Meanwhile, the effect of different components of microplasma was studied in the optimum conditions (The flow rate was 5 L/min inactivation distance was 2 cm). The results showed that electrically neutral active species was the main factor of inactivation rather than heating effect, ultraviolet radiation and charged particles. Finally the experiments of thallus change proved that microplasma jet had etching effect on cell membrane. It also found that microplasma could degrade organic material like protein. Furthermore, the images of scanning electron microscope (SEM) revealed the change of cell morphology step by step in the whole process of inactivation.
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Qualitation and Quantitation on Microplasma Jet for Bacteria Inactivation
Du, ChangMing; Liu, Ya; Huang, YaNi; Li, ZiMing; Men, Rui; Men, Yue; Tang, Jun
2016-01-01
In this work, a self-made microplasma jet system was used to conduct the qualitation and quantitation of inactivation with Escherichia coli as the target bacteria. The logarithmic concentration and the size of antimicrobial rings served as the evaluation parameters, respectively. The effect of various parameters on inactivation effect was studied. The results showed that the majority of bacteria had been inactivated in 30 s. The inactivation effect enhanced and then weakened with the increase of air flow rate, and receded as the extension of treatment distance. The effect with different carrier gases showed as follows: oxygen > air > nitrogen > argon. Meanwhile, the effect of different components of microplasma was studied in the optimum conditions (The flow rate was 5 L/min; inactivation distance was 2 cm). The results showed that electrically neutral active species was the main factor of inactivation rather than heating effect, ultraviolet radiation and charged particles. Finally the experiments of thallus change proved that microplasma jet had etching effect on cell membrane. It also found that microplasma could degrade organic material like protein. Furthermore, the images of scanning electron microscope (SEM) revealed the change of cell morphology step by step in the whole process of inactivation. PMID:26732987
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Arginine inactivates human herpesvirus 2 and inhibits genital herpesvirus infection.
Ikeda, Keiko; Yamasaki, Hisashi; Minami, Sawako; Suzuki, Yukiko; Tsujimoto, Kazuko; Sekino, Yoshihisa; Irie, Hiroshi; Arakawa, Tsutomu; Koyama, A Hajime
2012-12-01
Arginine, among the amino acids, has demonstrated unique properties, including suppression of protein-protein interactions and virus inactivation. We investigated the effects of arginine on the infectivity of human herpesvirus 2 (HHV-2) and the potential application of arginine as a chemotherapeutic agent against genital herpes. Arginine directly inactivated HHV-2 and characterization of the inactivation demonstrated that 1 M arginine at pH 4.3 inactivated the virus more efficiently compared to 0.1 M citrate or 1 M sodium chloride, indicating that neither acidic pH nor ionic strength alone is sufficient for virus inactivation. The effect of arginine was rapid and concentration-dependent. Although virus inactivation was efficient at an acidic pH, arginine inactivated the virus even at a neutral pH, provided that a higher arginine concentration and prolonged incubation time were used. In addition, arginine suppressed the multiplication of HHV-2 under the conditions at which its effect on cell viability was insignificant. Pilot mouse model studies revealed a marked suppression of death by arginine when the mice were infected with HHV-2 through the vaginal route, followed by an intermittent application of acidic arginine by vaginal instillation.
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Fineberg, Jeffrey D.; Ritter, David M.
2012-01-01
A-type voltage-gated K+ (Kv) channels self-regulate their activity by inactivating directly from the open state (open-state inactivation [OSI]) or by inactivating before they open (closed-state inactivation [CSI]). To determine the inactivation pathways, it is often necessary to apply several pulse protocols, pore blockers, single-channel recording, and kinetic modeling. However, intrinsic hurdles may preclude the standardized application of these methods. Here, we implemented a simple method inspired by earlier studies of Na+ channels to analyze macroscopic inactivation and conclusively deduce the pathways of inactivation of recombinant and native A-type Kv channels. We investigated two distinct A-type Kv channels expressed heterologously (Kv3.4 and Kv4.2 with accessory subunits) and their native counterparts in dorsal root ganglion and cerebellar granule neurons. This approach applies two conventional pulse protocols to examine inactivation induced by (a) a simple step (single-pulse inactivation) and (b) a conditioning step (double-pulse inactivation). Consistent with OSI, the rate of Kv3.4 inactivation (i.e., the negative first derivative of double-pulse inactivation) precisely superimposes on the profile of the Kv3.4 current evoked by a single pulse because the channels must open to inactivate. In contrast, the rate of Kv4.2 inactivation is asynchronous, already changing at earlier times relative to the profile of the Kv4.2 current evoked by a single pulse. Thus, Kv4.2 inactivation occurs uncoupled from channel opening, indicating CSI. Furthermore, the inactivation time constant versus voltage relation of Kv3.4 decreases monotonically with depolarization and levels off, whereas that of Kv4.2 exhibits a J-shape profile. We also manipulated the inactivation phenotype by changing the subunit composition and show how CSI and CSI combined with OSI might affect spiking properties in a full computational model of the hippocampal CA1 neuron. This work unambiguously elucidates contrasting inactivation pathways in neuronal A-type Kv channels and demonstrates how distinct pathways might impact neurophysiological activity. PMID:23109714
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Mechanism of Cd2+-coordination during Slow Inactivation in Potassium Channels
Raghuraman, H.; Cordero-Morales, Julio F.; Jogini, Vishwanath; Pan, Albert C.; Kollewe, Astrid; Roux, Benoît; Perozo, Eduardo
2013-01-01
Summary In K+ channels, rearrangements of the pore outer-vestibule have been associated with C-type inactivation gating. Paradoxically, the crystal structure of Open/C-type inactivated KcsA suggest these movements to be modest in magnitude. Here, we show that under physiological conditions, the KcsA outer-vestibule undergoes relatively large dynamic rearrangements upon inactivation. External Cd2+ enhances the rate of C-type inactivation in an outer-vestibule cysteine mutant (Y82C) via metal-bridge formation. This effect is not present in a non-inactivating mutant (E71A/Y82C). Tandem dimer and tandem tetramer constructs of equivalent cysteine mutants in KcsA and Shaker K+ channels demonstrate that these Cd2+ metal bridges are formed only between adjacent subunits. This is well supported by molecular dynamics simulations. Based on the crystal structure of Cd2+-bound Y82C-KcsA in the closed state, together with EPR distance measurements in the KcsA outer-vestibule, we suggest that subunits must dynamically come in close proximity as the channels undergo inactivation. PMID:22771214
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Open- and closed-state fast inactivation in sodium channels
Lehmann-Horn, Frank; Holzherr, Boris D
2011-01-01
The role of sodium channel closed-state fast inactivation in membrane excitability is not well understood. We compared open- and closed-state fast inactivation, and the gating charge immobilized during these transitions, in skeletal muscle channel hNaV1.4. A significant fraction of total charge movement and its immobilization occurred in the absence of channel opening. Simulated action potentials in skeletal muscle fibers were attenuated when pre-conditioned by subthreshold depolarization. Anthopleurin A, a site-3 toxin that inhibits gating charge associated with the movement of DIVS4, was used to assess the role of this voltage sensor in closed-state fast inactivation. Anthopleurin elicited opposing effects on the gating mode, kinetics and charge immobilized during open- versus closed-state fast inactivation. This same toxin produced identical effects on recovery of channel availability and remobilization of gating charge, irrespective of route of entry into fast inactivation. Our findings suggest that depolarization promoting entry into fast inactivation from open versus closed states provides access to the IFMT receptor via different rate-limiting conformational translocations of DIVS4. PMID:21099342
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McGuigan, K G; Joyce, T M; Conroy, R M; Gillespie, J B; Elmore-Meegan, M
1998-06-01
A series of experiments is reported to identify and characterize the inactivation process in operation when drinking water, heavily contaminated with a Kenyan isolate of Escherichia coli, is stored in transparent plastic bottles that are then exposed to sunlight. The roles of optical and thermal inactivation mechanisms are studied in detail by simulating conditions of optical irradiance, water turbidity and temperature, which were recorded during a series of solar disinfection measurements carried out in the Kenyan Rift Valley. Optical inactivation effects are observed even in highly turbid water (200 ntu) and at low irradiances of only 10 mW cm-2. Thermal inactivation is found to be important only at water temperatures above 45 degrees C, at which point strong synergy between optical and thermal inactivation processes is observed. The results confirm that, where strong sunshine is available, solar disinfection of drinking water is an effective, low cost method for improving water quality and may be of particular use to refugee camps in disaster areas. Strategies for improving bacterial inactivation are discussed.
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Crivellone, M D; Hermodson, M; Axelrod, B
1985-03-10
Potassium ferrate, an analog of orthophosphate and a potent oxidizing agent, was found to irreversibly inactivate porcine muscle adenylate kinase. Inhibition was prevented by competitive inhibitors or substrates, indicating that the action of ferrate was site-specific. Inactivation was accompanied by the loss of Cys-25 and Tyr-95. P1,P5-di(adenosine 5')-pentaphosphate (10(-7) M), a powerful competitive inhibitor, gave 50% protection to the enzyme from ferrate inactivation. No loss of tyrosine or cysteine residues was observed under conditions of total protection. The degree of inactivation was proportional to the amount of Tyr-95 destroyed. However, Cys-25 was totally oxidized when only 55% inactivation had occurred. Partially inactivated enzyme exhibited a Km for ATP and AMP similar to that of the untreated enzyme. It appears that Cys-25 may be proximate to a phosphate-binding site but is not directly involved in the catalytic reaction. The results suggest that Tyr-95 is located in the vicinity of a phosphate-binding region of adenylate kinase and is essential for enzyme activity.
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Endoplasmic Reticulum Stress as a Mediator of Neurotoxin-Induced Dopamine Neuron Death
2006-07-01
reversible reduction in choline acetyl- transferase concentration in rat hypoglossal nucleus after hypoglossal nerve transection. Nature 275, 324–325...cally, analogs were evaluated for their ability to enhance choline acetyltransferase (ChAT) activity in embryonic rat spinal cord and basal forebrain...of ibotenate, CEP1347 protected basal forebrain cholinergic neurons.102 In a model of apoptosis induced in auditory hair cells by noise trauma, CEP1347
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Zhou, Zhu-Juan; Zheng, Jian; He, Ying
2002-08-01
To make approach to the relationship between the changes of free zinc and ischemic neuronal damage in hippocampus after forebrain ischemia/reperfusion. The models of forebrain ischemia/reperfusion were established in rats. The contents of free Zn2+ were measured by TSQ fluorescence method. The Zn2+ chelator (CaEDTA) was injected into lateral ventricles in order to evaluate the effect of free Zn2+ on ischemic neuronal damage. (1) Zn2+ fluorescence in the hilus of dentate gyrus, CA3 region and the stratum radiatum and stratum oriens of CA1 decreased slightly at forty-eight hours after reperfusion. From seventy-two hours to ninety-six hour after reperfusion, the decreased fluorescence gradually returned to the normal level, but some fluorescence dots were found in pyramidal neurons of CA1 and the hilus of dentate gyrus. Seven days after reperfusion, all the changes of the fluorescence almost recovered. (2) The cell membrane-impermeable Zn2+ chelator CaEDTA could reduce the intracellular concentration of free Zn2+ and reduced neuronal damage after forebrain ischemia/reperfusion. (1) The synaptic vesicle Zn2+ released and then translocated into postsynaptic neurons after forebrain ischemia/reperfusion and played a role in ischemic neuronal damage. (2) The cell membrane-impermeable chelator CaEDTA could provide neuroprotection.
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Ascending connections to the forebrain in the Tegu lizard.
Lohman, A H; van Woerden-Verkley, I
1978-12-01
The ascending connections to the striatum and the cortex of the Tegu lizard, Tupinambis nigropunctatus, were studied by means of anterograde fiber degeneration and retrograde axonal transport. The striatum receives projections by way of the dorsal peduncle of the lateral forebrain bundle from four dorsal thalamic nuclei: nucleus rotundus, nucleus reuniens, the posterior part of the dorsal lateral geniculate nucleus and nucleus dorsomedialis. The former three nuclei project to circumscribed areas of the dorsal striatum, whereas nucleus dorsomedialis has a distribution to the whole dorsal striatum. Other sources of origin to the striatum are the mesencephalic reticular formation, substantia nigra and nucleus cerebelli lateralis. With the exception of the latter afferentation all these projections are ipsilateral. The ascending connections to the pallium originate for the major part from nucleus dorsolateralis anterior of the dorsal thalamus. The fibers course in both the medial forebrain bundle and the dorsal peduncle of the lateral forebrain bundle and terminate ipsilaterally in the middle of the molecular layer of the small-celled part of the mediodorsal cortex and bilaterally above the intermediate region of the dorsal cortex. The latter area is reached also by fibers from the septal area. The large-celled part of the mediodorsal cortex receives projections from nucleus raphes superior and the corpus mammillare.
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Katayama, Yukitoshi; Sakamoto, Tatsuya; Saito, Kazuhiro; Tsuchimochi, Hirotsugu; Kaiya, Hiroyuki; Watanabe, Taro; Pearson, James T; Takei, Yoshio
2018-01-12
Thirst aroused in the forebrain by angiotensin II (AngII) or buccal drying motivates terrestrial vertebrates to search for water, whereas aquatic fish can drink surrounding water only by reflex swallowing generated in the hindbrain. Indeed, AngII induces drinking through the hindbrain even after removal of the whole forebrain in aquatic fish. Here we show that AngII induces thirst also in the amphibious mudskipper goby without direct action on the forebrain, but through buccal drying. Intracerebroventricular injection of AngII motivated mudskippers to move into water and drink as with tetrapods. However, AngII primarily increased immunoreactive c-Fos at the hindbrain swallowing center where AngII receptors were expressed, as in other ray-finned fish, and such direct action on the forebrain was not found. Behavioural analyses showed that loss of buccal water on land by AngII-induced swallowing, by piercing holes in the opercula, or by water-absorptive gel placed in the cavity motivated mudskippers to move to water for refilling. Since sensory detection of water at the bucco-pharyngeal cavity like 'dry mouth' has recently been noted to regulate thirst in mammals, similar mechanisms seem to have evolved in distantly related species in order to solve osmoregulatory problems during terrestrialization.
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Frankel, Paul S; Cunningham, Kathryn A
2002-12-27
The hallucinogen d-lysergic acid diethylamide (d-LSD) evokes dramatic somatic and psychological effects. In order to analyze the neural activation induced by this unique psychoactive drug, we tested the hypothesis that expression of the immediate-early gene product c-Fos is induced in specific regions of the rat forebrain by a relatively low, behaviorally active, dose of d-LSD (0.16 mg/kg, i.p.); c-Fos protein expression was assessed at 30 min, and 1, 2 and 4 h following d-LSD injection. A time- and region-dependent expression of c-Fos was observed with a significant increase (P<0.05) in the number of c-Fos-positive cells detected in the anterior cingulate cortex at 1 h, the shell of the nucleus accumbens at 1 and 2 h, the bed nucleus of stria terminalis lateral at 2 h and the paraventricular hypothalamic nucleus at 1, 2 and 4 h following systemic d-LSD administration. These data demonstrate a unique pattern of c-Fos expression in the rat forebrain following a relatively low dose of d-LSD and suggest that activation of these forebrain regions contributes to the unique behavioral effects of d-LSD. Copyright 2002 Elsevier Science B.V.
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Disconnection of the Ascending Arousal System in Traumatic Coma
Edlow, Brian L.; Haynes, Robin L.; Takahashi, Emi; Klein, Joshua P.; Cummings, Peter; Benner, Thomas; Greer, David M.; Greenberg, Steven M.; Wu, Ona; Kinney, Hannah C.; Folkerth, Rebecca D.
2013-01-01
Traumatic coma is associated with disruption of axonal pathways throughout the brain but the specific pathways involved in humans are incompletely understood. In this study, we used high angular resolution diffusion imaging (HARDI) to map the connectivity of axonal pathways that mediate the 2 critical components of consciousness – arousal and awareness – in the postmortem brain of a 62-year-old woman with acute traumatic coma and in 2 control brains. HARDI tractography guided tissue sampling in the neuropathological analysis. HARDI tractography demonstrated complete disruption of white matter pathways connecting brainstem arousal nuclei to the basal forebrain and thalamic intralaminar and reticular nuclei. In contrast, hemispheric arousal pathways connecting the thalamus and basal forebrain to the cerebral cortex were only partially disrupted, as were the cortical “awareness pathways.” Neuropathologic examination, which utilized β-amyloid precursor protein and fractin immunomarkers, revealed axonal injury in the white matter of the brainstem and cerebral hemispheres that corresponded to sites of HARDI tract disruption. Axonal injury was also present within the grey matter of the hypothalamus, thalamus, basal forebrain, and cerebral cortex. We propose that traumatic coma may be a subcortical disconnection syndrome related to the disconnection of specific brainstem arousal nuclei from the thalamus and basal forebrain. PMID:23656993
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Fast inactivation of delayed rectifier K conductance in squid giant axon and its cell bodies.
Mathes, C; Rosenthal, J J; Armstrong, G M; Gilly, W F
1997-04-01
Inactivation of delayed rectifier K conductance (gk) was studied in squid giant axons and in the somata of giant fiber lobe (GFL) neurons. Axon measurements were made with an axial wire voltage clamp by pulsing to VK (approximately -10 mV in 50-70 mM external K) for a variable time and then assaying available gK with a strong, brief test pulse. GFL cells were studied with whole-cell patch clamp using the same prepulse procedure as well as with long depolarizations. Under our experimental conditions (12-18 degrees C, 4 mM internal MgATP) a large fraction of gK inactivates within 250 ms at -10 mV in both cell bodies and axons, although inactivation tends to be more complete in cell bodies. Inactivation in both preparations shows two kinetic components. The faster component is more temperature-sensitive and becomes very prominent above 12 degrees C. Contribution of the fast component to inactivation shows a similar voltage dependence to that of gK, suggesting a strong coupling of this inactivation path to the open state. Omission of internal MgATP or application of internal protease reduces the amount of fast inactivation. High external K decreases the amount of rapidly inactivating IK but does not greatly alter inactivation kinetics. Neither external nor internal tetraethylammonium has a marked effect on inactivation kinetics. Squid delayed rectifier K channels in GFL cell bodies and giant axons thus share complex fast inactivation properties that do not closely resemble those associated with either C-type or N-type inactivation of cloned Kvl channels studied in heterologous expression systems.
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A specific inactivator of mammalian C'4 isolated from nurse shark (Ginglymostoma cirratum) serum.
Jensen, J A
1969-08-01
A material which specifically inactivates mammalian C'4 was isolated from low ionic strength precipitates of nurse shark serum. The C'4 inactivator was not detected in whole serum. The conditions of its generation and its immunoelectrophoretic behavior seem to indicate that it is an enzymatically formed cleavage product of a precursor contained in whole shark serum. The inactivator was partially purified and characterized. It had an S-value of 3.3 (sucrose gradient) which was in agreement with its retardation on gel filtration, was stable between pH 5.0 and 10.0, had a half-life of 5 min at 56 degrees C, pH 7.5, was inactivated by trypsin and was nontoxic. Its powerful anticomplementary activity in vitro and in vivo was solely due to the rapid inactivation of C'4; no other complement components were affected. No cofactor requirement was observed for the equally rapid inactivation of highly purified human and guinea pig C'4. The kinetics of C'4 inactivation and TAME hydrolysis, the greater anodic mobility of inactivated human C'4, and the influence of temperature on the rate of inactivation suggest that the inactivator is an enzyme and C'4 its substrate. This conclusion was supported by the more recent detection of a split product of C'4. Intravenous administration of the C'4 inactivator could prevent lethal Forssman shock and suppress the Arthus reaction in guinea pigs; it prolonged significantly the rejection time of renal xenografts but had no detectable effect on passive cutaneous anaphylaxis. Anaphylatoxin could be generated in C'4 depleted guinea pig serum with the cobra venom factor, but not with immune precipitates. The possible relationship between C'1 esterase and the C'4 inactivator is discussed on the basis of similarities and dissimilarities.
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Fast Inactivation of Delayed Rectifier K Conductance in Squid Giant Axon and Its Cell Bodies
Mathes, Chris; Rosenthal, Joshua J.C.; Armstrong, Clay M.; Gilly, William F.
1997-01-01
Inactivation of delayed rectifier K conductance (gK) was studied in squid giant axons and in the somata of giant fiber lobe (GFL) neurons. Axon measurements were made with an axial wire voltage clamp by pulsing to VK (∼−10 mV in 50–70 mM external K) for a variable time and then assaying available gK with a strong, brief test pulse. GFL cells were studied with whole-cell patch clamp using the same prepulse procedure as well as with long depolarizations. Under our experimental conditions (12–18°C, 4 mM internal MgATP) a large fraction of gK inactivates within 250 ms at −10 mV in both cell bodies and axons, although inactivation tends to be more complete in cell bodies. Inactivation in both preparations shows two kinetic components. The faster component is more temperature-sensitive and becomes very prominent above 12°C. Contribution of the fast component to inactivation shows a similar voltage dependence to that of gK, suggesting a strong coupling of this inactivation path to the open state. Omission of internal MgATP or application of internal protease reduces the amount of fast inactivation. High external K decreases the amount of rapidly inactivating IK but does not greatly alter inactivation kinetics. Neither external nor internal tetraethylammonium has a marked effect on inactivation kinetics. Squid delayed rectifier K channels in GFL cell bodies and giant axons thus share complex fast inactivation properties that do not closely resemble those associated with either C-type or N-type inactivation of cloned Kv1 channels studied in heterologous expression systems. PMID:9101403
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Monochloramine inactivation of bacterial select agents.
Rose, Laura J; Rice, Eugene W; Hodges, Lisa; Peterson, Alicia; Arduino, Matthew J
2007-05-01
Seven species of bacterial select agents were tested for susceptibility to monochloramine. Under test conditions, the monochloramine routinely maintained in potable water would reduce six of the species by 2 orders of magnitude within 4.2 h. Bacillus anthracis spores would require up to 3.5 days for the same inactivation with monochloramine.
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Structure of suicide-inactivated. beta. -hydroxydecanoyl-thioester dehydrase
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schwab, J.M.; Ho, C.K.; Li, W.B.
..beta..-Hydroxydecanoylthioester dehydrase, the key enzyme in biosynthesis of unsaturated fatty acids under anaerobic conditions, equilibrates thioesters of (R)-3-hydroxydecanoic acid, E-2-decenoic acid, and Z-3-decenoic acid. Dehydrase is irreversibly inactivated by the N-acetylcysteamine thioester of 3-decynoic acid (3-decynoyl-NAC), via dehydrase-catalyzed isomerization to 2,3-decadienoyl-NAC. To probe the relationship between normal catalysis and suicide inactivation, the structure of the inactivated enzyme has been studied. 3-(2-/sup 13/C)Decynoyl-NAC was synthesized and incubated with dehydrase. /sup 13/C NMR showed that attack of 2,3-decadienoyl-NAC by the active site histidine gives 3-histidinyl-3-decenoyl-NAC, which slowly rearranges to the more stable ..delta../sup 2/ isomer. Model histidine-allene adducts have been made andmore » characterized. Analysis of NMR data show that the C=C configuration of the decenoyl moiety of enzyme-bound inactivator is E. The suggestion that the mechanism of dehydrase inactivation parallels its normal mechanism of action is supported these findings.« less
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Endepols, H; Jungnickel, J; Braun, K
2001-01-01
Cocultures of the learning-relevant forebrain region mediorostral neostriatum and hyperstriatum ventrale (MNH) and its main glutamatergic input area nucleus dorsomedialis anterior thalami/posterior thalami were morphologically and physiologically characterized. Synaptic contacts of thalamic fibers were light- and electron-microscopically detected on MNH neurons by applying the fluorescence tracer DiI-C18(3) into the thalamus part of the coculture. Most thalamic synapses on MNH neurons were symmetric and located on dendritic shafts, but no correlation between Gray-type ultrastructure and dendritic localization was found. Using intracellular current clamp recordings, we found that the electrophysiological properties, such as input resistance, time constant, action potential threshold, amplitude, and duration of MNH neurons, remain stable for over 30 days in vitro. Pharmacological blockade experiments revealed glutamate as the main neurotransmitter of thalamic synapses on MNH neurons, which were also found on inhibitory neurons. High frequency stimulation of thalamic inputs evoked synaptic potentiation in 22% of MNH neurons. The results indicate that DMA/DMP-MNH cocultures, which can be maintained under stable conditions for at least 4 weeks, provide an attractive in vitro model for investigating synaptic plasticity in the avian brain.
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Intact working memory in the absence of forebrain neuronal glycine transporter 1
Dubroqua, Sylvain; Serrano, Lucas; Boison, Detlev; Feldon, Joram; Gargiulo, Pascual A.; Yee, Benjamin K.
2012-01-01
Glycine transporter 1 (GlyT1) is a potential pharmacological target to ameliorate memory deficits attributable to N-methyl-d-aspartate receptor (NMDAR) hypofunction. Disruption of glycine-reuptake near excitatory synapses is expected to enhance NMDAR function by increasing glycine-B site occupancy. Genetic models with conditional GlyT1 deletion restricted to forebrain neurons have yielded several promising promnesic effects, yet its impact on working memory function remains essentially unanswered because a previous attempt had yielded un-interpretable outcomes. The present study clarified this important outstanding lacuna using a within-subject multi-paradigm approach. Here, a consistent lack of effects was convincingly demonstrated across three working memory test paradigms – the radial arm maze, the cheeseboard maze, and the water maze. These null outcomes contrasted with the phenotype of enhanced working memory performance seen in mutant mice with GlyT1 deletion extended to cortical/hippocampal glial cells. It follows that glial-based GlyT1 might be more closely linked to the modulation of working memory function, and raises the possibility that neuronal and glial GlyT1 may regulate cognitive functions via dissociable mechanisms. PMID:22342492
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Endepols, Heike; Jungnickel, Julia; Braun, Katharina
2001-01-01
Cocultures of the learning-relevant forebrain region mediorostrai neostriatum and hyperstriatum ventrale (MNH) and its main glutamatergic input area nucleus dorsomedialis anterior thalami/posterior thalami were morphologically and physiologically characterized. Synaptic contacts of thalamic fibers were lightand electron-microscopically detected on MNH neurons by applying the fluorescence tracer DiI-C18(3) into the thalamus part of the coculture. Most thalamic synapses on MNH neurons were symmetric and located on dendritic shafts, but no correlation between Gray-type ultrastructure and dendritic localization was found. Using intraceilular current clamp recordings, we found that the electrophysiological properties, such as input resistance, time constant, action potential threshold, amplitude, and duration of MNH neurons, remain stable for over 30 days in vitro. Pharmacological blockade experiments revealed glutamate as the main neurotransmitter of thalamic synapses on MNH neurons, which were also found on inhibitory neurons. High frequency stimulation of thalamic inputs evoked synaptic potentiation in 22% of MNH neurons. The results indicate that DMA/DMP-MNH cocultures, which can be maintained under stable conditions for at least 4 weeks, provide an attractive in vitro model for investigating synaptic plasticity in the avian brain. PMID:12018771
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Temporal and Region-Specific Requirements of αCaMKII in Spatial and Contextual Learning
Achterberg, Katharina G.; Buitendijk, Gabriëlle H.S.; Kool, Martijn J.; Goorden, Susanna M.I.; Post, Laura; Slump, Denise E.; Silva, Alcino J.; van Woerden, Geeske M.
2014-01-01
The α isoform of the calcium/calmodulin-dependent protein kinase II (αCaMKII) has been implicated extensively in molecular and cellular mechanisms underlying spatial and contextual learning in a wide variety of species. Germline deletion of Camk2a leads to severe deficits in spatial and contextual learning in mice. However, the temporal and region-specific requirements for αCaMKII have remained largely unexplored. Here, we generated conditional Camk2a mutants to examine the influence of spatially restricted and temporally controlled expression of αCaMKII. Forebrain-specific deletion of the Camk2a gene resulted in severe deficits in water maze and contextual fear learning, whereas mice with deletion restricted to the cerebellum learned normally. Furthermore, we found that temporally controlled deletion of the Camk2a gene in adult mice is as detrimental as germline deletion for learning and synaptic plasticity. Together, we confirm the requirement for αCaMKII in the forebrain, but not the cerebellum, in spatial and contextual learning. Moreover, we highlight the absolute requirement for intact αCaMKII expression at the time of learning. PMID:25143599
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Descending projections from the basal forebrain to the orexin neurons in mice.
Agostinelli, Lindsay J; Ferrari, Loris L; Mahoney, Carrie E; Mochizuki, Takatoshi; Lowell, Bradford B; Arrigoni, Elda; Scammell, Thomas E
2017-05-01
The orexin (hypocretin) neurons play an essential role in promoting arousal, and loss of the orexin neurons results in narcolepsy, a condition characterized by chronic sleepiness and cataplexy. The orexin neurons excite wake-promoting neurons in the basal forebrain (BF), and a reciprocal projection from the BF back to the orexin neurons may help promote arousal and motivation. The BF contains at least three different cell types (cholinergic, glutamatergic, and γ-aminobutyric acid (GABA)ergic neurons) across its different regions (medial septum, diagonal band, magnocellular preoptic area, and substantia innominata). Given the neurochemical and anatomical heterogeneity of the BF, we mapped the pattern of BF projections to the orexin neurons across multiple BF regions and neuronal types. We performed conditional anterograde tracing using mice that express Cre recombinase only in neurons producing acetylcholine, glutamate, or GABA. We found that the orexin neurons are heavily apposed by axon terminals of glutamatergic and GABAergic neurons of the substantia innominata (SI) and magnocellular preoptic area, but there was no innervation by the cholinergic neurons. Channelrhodopsin-assisted circuit mapping (CRACM) demonstrated that glutamatergic SI neurons frequently form functional synapses with the orexin neurons, but, surprisingly, functional synapses from SI GABAergic neurons were rare. Considering their strong reciprocal connections, BF and orexin neurons likely work in concert to promote arousal, motivation, and other behaviors. J. Comp. Neurol. 525:1668-1684, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
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Review: Efficiency of Physical and Chemical Treatments on the Inactivation of Dairy Bacteriophages
Guglielmotti, Daniela M.; Mercanti, Diego J.; Reinheimer, Jorge A.; Quiberoni, Andrea del L.
2011-01-01
Bacteriophages can cause great economic losses due to fermentation failure in dairy plants. Hence, physical and chemical treatments of raw material and/or equipment are mandatory to maintain phage levels as low as possible. Regarding thermal treatments used to kill pathogenic bacteria or achieve longer shelf-life of dairy products, neither low temperature long time nor high temperature short time pasteurization were able to inactivate most lactic acid bacteria (LAB) phages. Even though most phages did not survive 90°C for 2 min, there were some that resisted 90°C for more than 15 min (conditions suggested by the International Dairy Federation, for complete phage destruction). Among biocides tested, ethanol showed variable effectiveness in phage inactivation, since only phages infecting dairy cocci and Lactobacillus helveticus were reasonably inactivated by this alcohol, whereas isopropanol was in all cases highly ineffective. In turn, peracetic acid has consistently proved to be very fast and efficient to inactivate dairy phages, whereas efficiency of sodium hypochlorite was variable, even among different phages infecting the same LAB species. Both alkaline chloride foam and ethoxylated non-ylphenol with phosphoric acid were remarkably efficient, trait probably related to their highly alkaline or acidic pH values in solution, respectively. Photocatalysis using UV light and TiO2 has been recently reported as a feasible option to industrially inactivate phages infecting diverse LAB species. Processes involving high pressure were barely used for phage inactivation, but until now most studied phages revealed high resistance to these treatments. To conclude, and given the great phage diversity found on dairies, it is always advisable to combine different anti-phage treatments (biocides, heat, high pressure, photocatalysis), rather than using them separately at extreme conditions. PMID:22275912
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Inactivation of Bacillus spores inoculated in milk by Ultra High Pressure Homogenization.
Amador Espejo, Genaro Gustavo; Hernández-Herrero, M M; Juan, B; Trujillo, A J
2014-12-01
Ultra High-Pressure Homogenization treatments at 300 MPa with inlet temperatures (Ti) of 55, 65, 75 and 85 °C were applied to commercial Ultra High Temperature treated whole milk inoculated with Bacillus cereus, Bacillus licheniformis, Bacillus sporothermodurans, Bacillus coagulans, Geobacillus stearothermophilus and Bacillus subtilis spores in order to evaluate the inactivation level achieved. Ultra High-Pressure Homogenization conditions at 300 MPa with Ti = 75 and 85 °C were capable of a spore inactivation of ∼5 log CFU/mL. Furthermore, under these processing conditions, commercial sterility (evaluated as the complete inactivation of the inoculated spores) was obtained in milk, with the exception of G. stearothermophilus and B. subtilis treated at 300 MPa with Ti = 75 °C. The results showed that G. stearothermophilus and B. subtilis have higher resistance to the Ultra High-Pressure Homogenization treatments applied than the other microorganisms inoculated and that a treatment performed at 300 MPa with Ti = 85 °C was necessary to completely inactivate these microorganisms at the spore level inoculated (∼1 × 10(6) CFU/mL). Besides, a change in the resistance of B. licheniformis, B. sporothermodurans, G. stearothermophilus and B. subtilis spores was observed as the inactivation obtained increased remarkably in treatments performed with Ti between 65 and 75 °C. This study provides important evidence of the suitability of UHPH technology for the inactivation of spores in high numbers, leading to the possibility of obtaining commercially sterile milk. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Carvacrol suppresses high pressure high temperature inactivation of Bacillus cereus spores.
Luu-Thi, Hue; Corthouts, Jorinde; Passaris, Ioannis; Grauwet, Tara; Aertsen, Abram; Hendrickx, Marc; Michiels, Chris W
2015-03-16
The inactivation of bacterial spores generally proceeds faster and at lower temperatures when heat treatments are conducted under high pressure, and high pressure high temperature (HPHT) processing is, therefore, receiving an increased interest from food processors. However, the mechanisms of spore inactivation by HPHT treatment are poorly understood, particularly at moderately elevated temperature. In the current work, we studied inactivation of the spores of Bacillus cereus F4430/73 by HPHT treatment for 5 min at 600MPa in the temperature range of 50-100°C, using temperature increments of 5°C. Additionally, we investigated the effect of the natural antimicrobial carvacrol on spore germination and inactivation under these conditions. Spore inactivation by HPHT was less than about 1 log unit at 50 to 70°C, but gradually increased at higher temperatures up to about 5 log units at 100°C. DPA release and loss of spore refractility in the spore population were higher at moderate (≤65°C) than at high (≥70°C) treatment temperatures, and we propose that moderate conditions induced the normal physiological pathway of spore germination resulting in fully hydrated spores, while at higher temperatures this pathway was suppressed and replaced by another mechanism of pressure-induced dipicolinic acid (DPA) release that results only in partial spore rehydration, probably because spore cortex hydrolysis is inhibited. Carvacrol strongly suppressed DPA release and spore rehydration during HPHT treatment at ≤65°C and also partly inhibited DPA release at ≥65°C. Concomitantly, HPHT spore inactivation was reduced by carvacrol at 65-90°C but unaffected at 95-100°C. Copyright © 2014 Elsevier B.V. All rights reserved.
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Jonges, Marcel; Liu, Wai Ming; van der Vries, Erhard; Jacobi, Ronald; Pronk, Inge; Boog, Claire; Koopmans, Marion; Meijer, Adam; Soethout, Ernst
2010-01-01
Introduction of a new influenza virus in humans urges quick analysis of its virological and immunological characteristics to determine the impact on public health and to develop protective measures for the human population. At present, however, the necessity of executing pandemic influenza virus research under biosafety level 3 (BSL-3) high-containment conditions severely hampers timely characterization of such viruses. We tested heat, formalin, Triton X-100, and β-propiolactone treatments for their potencies in inactivating human influenza A(H3N2) and avian A(H7N3) viruses, as well as seasonal and pandemic A(H1N1) virus isolates, while allowing the specimens to retain their virological and immunological properties. Successful heat inactivation coincided with the loss of hemagglutinin (HA) and neuraminidase (NA) characteristics, and β-propiolactone inactivation reduced the hemagglutination titer and NA activity of the human influenza virus 10-fold or more. Although Triton X-100 treatment resulted in inconsistent HA activity, the NA activities in culture supernatants were enhanced consistently. Nonetheless, formalin treatment permitted the best retention of HA and NA properties. Triton X-100 treatment proved to be the easiest-to-use influenza virus inactivation protocol for application in combination with phenotypic NA inhibitor susceptibility assays, while formalin treatment preserved B-cell and T-cell epitope antigenicity, allowing the detection of both humoral and cellular immune responses. In conclusion, we demonstrated successful influenza virus characterization using formalin- and Triton X-100-inactivated virus samples. Application of these inactivation protocols limits work under BSL-3 conditions to virus culture, thus enabling more timely determination of public health impact and development of protective measures when a new influenza virus, e.g., pandemic A(H1N1)v virus, is introduced in humans. PMID:20089763
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Hossain, Md. Sohrab; Nik Ab Rahman, Nik Norulaini; Balakrishnan, Venugopal
2015-04-15
Highlights: • Supercritical carbon dioxide sterilization of clinical solid waste. • Inactivation of bacteria in clinical solid waste using supercritical carbon dioxide. • Reduction of the hazardous exposure of clinical solid waste. • Optimization of the supercritical carbon dioxide experimental conditions. - Abstract: Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO{sub 2}) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis,more » and gram-negative Escherichia coli in CSW. The effects of SC-CO{sub 2} sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO{sub 2}-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO{sub 2} exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials.« less
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Reversible Heat-Induced Inactivation of Chimeric β-Glucuronidase in Transgenic Plants1
Almoguera, Concepción; Rojas, Anabel; Jordano, Juan
2002-01-01
We compared the expression patterns in transgenic tobacco (Nicotiana tabacum) of two chimeric genes: a translational fusion to β-glucuronidase (GUS) and a transcriptional fusion, both with the same promoter and 5′-flanking sequences of Ha hsp17.7 G4, a small heat shock protein (sHSP) gene from sunflower (Helianthus annuus). We found that immediately after heat shock, the induced expression from the two fusions in seedlings was similar, considering chimeric mRNA or GUS protein accumulation. Surprisingly, we discovered that the chimeric GUS protein encoded by the translational fusion was mostly inactive in such conditions. We also found that this inactivation was fully reversible. Thus, after returning to control temperature, the GUS activity was fully recovered without substantial changes in GUS protein accumulation. In contrast, we did not find differences in the in vitro heat inactivation of the respective GUS proteins. Insolubilization of the chimeric GUS protein correlated with its inactivation, as indicated by immunoprecipitation analyses. The inclusion in another chimeric gene of the 21 amino-terminal amino acids from a different sHSP lead to a comparable reversible inactivation. That effect not only illustrates unexpected post-translational problems, but may also point to sequences involved in interactions specific to sHSPs and in vivo heat stress conditions. PMID:12011363
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Morphogenetic interaction of presumptive neural and mesodermal cells mixed in different ratios.
Toivonen, S; Saxen, L
1968-02-02
Cells of the presumptive forebrain region and axial mesoderm of Triturus neurulae were disaggregated and combined in different ratios. The differentiation of the central nervous systen in these explants was dependent on the relative amount of mesodermal cells present: an increase of mesodermal cells resulted in a corresponding increase in the frequency with which caudal structures of the central nervous system developed and a gradual loss of the forebrain formations.
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Ludwig Edinger: the vertebrate series and comparative neuroanatomy.
Patton, Paul
2015-01-01
At the end of the nineteenth century, Ludwig Edinger completed the first comparative survey of the microscopic anatomy of vertebrate brains. He is regarded as the founder of the field of comparative neuroanatomy. Modern commentators have misunderstood him to have espoused an anti-Darwinian linear view of brain evolution, harkening to the metaphysics of the scala naturae. This understanding arises, in part, from an increasingly contested view of nineteenth-century morphology in Germany. Edinger did espouse a progressionist, though not strictly linear, view of forebrain evolution, but his work also provided carefully documented evidence that brain stem structures vary in complexity independently from one another and across species in a manner that is not compatible with linear progress. This led Edinger to reject progressionism for all brain structures other than the forebrain roof, based on reasoning not too dissimilar from those his successors used to dismiss it for the forebrain roof.
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A subcortical inhibitory signal for behavioral arrest in the thalamus
Dugué, Guillaume P.; Bokor, Hajnalka; Rousseau, Charly V.; Maglóczky, Zsófia; Havas, László; Hangya, Balázs; Wildner, Hendrik; Zeilhofer, Hanns Ulrich; Dieudonné, Stéphane; Acsády, László
2016-01-01
Organization of behavior requires rapid coordination of brainstem and forebrain activity. The exact mechanisms of effective communication between these regions are presently unclear. The intralaminar thalamus (IL) probably serves as a central hub in this circuit by connecting the critical brainstem and forebrain areas. Here we found that GABAergic/glycinergic fibers ascending from the pontine reticular formation (PRF) of the brainstem evoke fast and reliable inhibition in the IL thalamus via large, multisynaptic terminals. This inhibition was fine-tuned through heterogeneous GABAergic/glycinergic receptor ratios expressed at individual synapses. Optogenetic activation of PRF axons in the IL of freely moving mice led to behavioral arrest and transient interruption of awake cortical activity. An afferent system with comparable morphological features was also found in the human IL. These data reveal an evolutionarily conserved ascending system which gates forebrain activity through fast and powerful synaptic inhibition of the IL thalamus. PMID:25706472
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Forebrain-Specific Loss of BMPRII in Mice Reduces Anxiety and Increases Object Exploration.
McBrayer, Zofeyah L; Dimova, Jiva; Pisansky, Marc T; Sun, Mu; Beppu, Hideyuki; Gewirtz, Jonathan C; O'Connor, Michael B
2015-01-01
To investigate the role of Bone Morphogenic Protein Receptor Type II (BMPRII) in learning, memory, and exploratory behavior in mice, a tissue-specific knockout of BMPRII in the post-natal hippocampus and forebrain was generated. We found that BMPRII mutant mice had normal spatial learning and memory in the Morris water maze, but showed significantly reduced swimming speeds with increased floating behavior. Further analysis using the Porsolt Swim Test to investigate behavioral despair did not reveal any differences in immobility between mutants and controls. In the Elevated Plus Maze, BMPRII mutants and Smad4 mutants showed reduced anxiety, while in exploratory tests, BMPRII mutants showed more interest in object exploration. These results suggest that loss of BMPRII in the mouse hippocampus and forebrain does not disrupt spatial learning and memory encoding, but instead impacts exploratory and anxiety-related behaviors.
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Forebrain-Specific Loss of BMPRII in Mice Reduces Anxiety and Increases Object Exploration
McBrayer, Zofeyah L.; Dimova, Jiva; Pisansky, Marc T.; Sun, Mu; Beppu, Hideyuki; Gewirtz, Jonathan C.; O’Connor, Michael B.
2015-01-01
To investigate the role of Bone Morphogenic Protein Receptor Type II (BMPRII) in learning, memory, and exploratory behavior in mice, a tissue-specific knockout of BMPRII in the post-natal hippocampus and forebrain was generated. We found that BMPRII mutant mice had normal spatial learning and memory in the Morris water maze, but showed significantly reduced swimming speeds with increased floating behavior. Further analysis using the Porsolt Swim Test to investigate behavioral despair did not reveal any differences in immobility between mutants and controls. In the Elevated Plus Maze, BMPRII mutants and Smad4 mutants showed reduced anxiety, while in exploratory tests, BMPRII mutants showed more interest in object exploration. These results suggest that loss of BMPRII in the mouse hippocampus and forebrain does not disrupt spatial learning and memory encoding, but instead impacts exploratory and anxiety-related behaviors. PMID:26444546
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Xu, Sa; Labuza, Theodore P.; Diez-Gonzalez, Francisco
2008-01-01
The milk supply is considered a primary route for a bioterrorism attack with Bacillus anthracis spores because typical high-temperature short-time (HTST) pasteurization conditions cannot inactivate spores. In the event of intentional contamination, an effective method to inactivate the spores in milk under HTST processing conditions is needed. This study was undertaken to identify combinations and concentrations of biocides that can inactivate B. anthracis spores at temperatures in the HTST range in less than 1 min. Hydrogen peroxide (HP), sodium hypochlorite (SH), and peroxyacetic acid (PA) were evaluated for their efficacy in inactivating spores of strains 7702, ANR-1, and 9131 in milk at 72, 80, and 85°C using a sealed capillary tube technique. Strains ANR-1 and 9131 were more resistant to all of the biocide treatments than strain 7702. Addition of 1,260 ppm SH to milk reduced the number of viable spores of each strain by 6 log CFU/ml in less than 90 and 60 s at 72 and 80°C, respectively. After neutralization, 1,260 ppm SH reduced the time necessary to inactivate 6 log CFU/ml (TTI6-log) at 80°C to less than 20 s. Treatment of milk with 7,000 ppm HP resulted in a similar level of inactivation in 60 s. Combined treatment with 1,260 ppm SH and 1,800 ppm HP inactivated spores of all strains in less than 20 s at 80°C. Mixing 15 ppm PA with milk containing 1,260 ppm SH resulted in TTI6-log of 25 and 12 s at 72 and 80°C, respectively. TTI6-log of less than 20 s were also achieved at 80°C by using two combinations of biocides: 250 ppm SH, 700 ppm HP, and 150 ppm PA; and 420 ppm SH (pH 7), 1,100 ppm HP, and 15 ppm PA. These results indicated that different combinations of biocides could consistently result in 6-log reductions in the number of B. anthracis spores in less than 1 min at temperatures in the HTST range. This information could be useful for developing more effective thermal treatment strategies which could be used in HTST milk plants to process contaminated milk for disposal and decontamination, as well as for potential protective measures. PMID:18390680
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Xu, Sa; Labuza, Theodore P; Diez-Gonzalez, Francisco
2008-06-01
The milk supply is considered a primary route for a bioterrorism attack with Bacillus anthracis spores because typical high-temperature short-time (HTST) pasteurization conditions cannot inactivate spores. In the event of intentional contamination, an effective method to inactivate the spores in milk under HTST processing conditions is needed. This study was undertaken to identify combinations and concentrations of biocides that can inactivate B. anthracis spores at temperatures in the HTST range in less than 1 min. Hydrogen peroxide (HP), sodium hypochlorite (SH), and peroxyacetic acid (PA) were evaluated for their efficacy in inactivating spores of strains 7702, ANR-1, and 9131 in milk at 72, 80, and 85 degrees C using a sealed capillary tube technique. Strains ANR-1 and 9131 were more resistant to all of the biocide treatments than strain 7702. Addition of 1,260 ppm SH to milk reduced the number of viable spores of each strain by 6 log CFU/ml in less than 90 and 60 s at 72 and 80 degrees C, respectively. After neutralization, 1,260 ppm SH reduced the time necessary to inactivate 6 log CFU/ml (TTI6-log) at 80 degrees C to less than 20 s. Treatment of milk with 7,000 ppm HP resulted in a similar level of inactivation in 60 s. Combined treatment with 1,260 ppm SH and 1,800 ppm HP inactivated spores of all strains in less than 20 s at 80 degrees C. Mixing 15 ppm PA with milk containing 1,260 ppm SH resulted in TTI6-log of 25 and 12 s at 72 and 80 degrees C, respectively. TTI6-log of less than 20 s were also achieved at 80 degrees C by using two combinations of biocides: 250 ppm SH, 700 ppm HP, and 150 ppm PA; and 420 ppm SH (pH 7), 1,100 ppm HP, and 15 ppm PA. These results indicated that different combinations of biocides could consistently result in 6-log reductions in the number of B. anthracis spores in less than 1 min at temperatures in the HTST range. This information could be useful for developing more effective thermal treatment strategies which could be used in HTST milk plants to process contaminated milk for disposal and decontamination, as well as for potential protective measures.
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The kinetics of inactivation of the rod phototransduction cascade with constant Ca2+i
1996-01-01
A rich variety of mechanisms govern the inactivation of the rod phototransduction cascade. These include rhodopsin phosphorylation and subsequent binding of arrestin; modulation of rhodopsin kinase by S- modulin (recoverin); regulation of G-protein and phosphodiesterase inactivation by GTPase-activating factors; and modulation of guanylyl cyclase by a high-affinity Ca(2+)-binding protein. The dependence of several of the inactivation mechanisms on Ca2+i makes it difficult to assess the contributions of these mechanisms to the recovery kinetics in situ, where Ca2+i is dynamically modulated during the photoresponse. We recorded the circulating currents of salamander rods, the inner segments of which are held in suction electrodes in Ringer's solution. We characterized the response kinetics to flashes under two conditions: when the outer segments are in Ringer's solution, and when they are in low-Ca2+ choline solutions, which we show clamp Ca2+i very near its resting level. At T = 20-22 degrees C, the recovery phases of responses to saturating flashes producing 10(2.5)-10(4.5) photoisomerizations under both conditions are characterized by a dominant time constant, tau c = 2.4 +/- 0.4 s, the value of which is not dependent on the solution bathing the outer segment and therefore not dependent on Ca2+i. We extended a successful model of activation by incorporating into it a first-order inactivation of R*, and a first-order, simultaneous inactivation of G-protein (G*) and phosphodiesterase (PDE*). We demonstrated that the inactivation kinetics of families of responses obtained with Ca2+i clamped to rest are well characterized by this model, having one of the two inactivation time constants (tau r* or tau PDE*) equal to tau c, and the other time constant equal to 0.4 +/- 0.06 s. PMID:8741728
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Oaks, Adam W; Zamarbide, Marta; Tambunan, Dimira E; Santini, Emanuela; Di Costanzo, Stefania; Pond, Heather L; Johnson, Mark W; Lin, Jeff; Gonzalez, Dilenny M; Boehler, Jessica F; Wu, Guangying K; Klann, Eric; Walsh, Christopher A; Manzini, M Chiara
2017-02-01
Loss-of-function (LOF) mutations in CC2D1A cause a spectrum of neurodevelopmental disorders, including intellectual disability, autism spectrum disorder, and seizures, identifying a critical role for this gene in cognitive and social development. CC2D1A regulates intracellular signaling processes that are critical for neuronal function, but previous attempts to model the human LOF phenotypes have been prevented by perinatal lethality in Cc2d1a-deficient mice. To overcome this challenge, we generated a floxed Cc2d1a allele for conditional removal of Cc2d1a in the brain using Cre recombinase. While removal of Cc2d1a in neuronal progenitors using Cre expressed from the Nestin promoter still causes death at birth, conditional postnatal removal of Cc2d1a in the forebrain via calcium/calmodulin-dependent protein kinase II-alpha (CamKIIa) promoter-driven Cre generates animals that are viable and fertile with grossly normal anatomy. Analysis of neuronal morphology identified abnormal cortical dendrite organization and a reduction in dendritic spine density. These animals display deficits in neuronal plasticity and in spatial learning and memory that are accompanied by reduced sociability, hyperactivity, anxiety, and excessive grooming. Cc2d1a conditional knockout mice therefore recapitulate features of both cognitive and social impairment caused by human CC2D1A mutation, and represent a model that could provide much needed insights into the developmental mechanisms underlying nonsyndromic neurodevelopmental disorders. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
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Meyer, F; Peterschmitt, Y; Louilot, A
2009-05-01
Latent inhibition has been found to be disrupted in patients with acute schizophrenia. Striatal dopaminergic dysregulation is commonly acknowledged in schizophrenia. This disease may be consecutive to a functional disconnection between integrative regions, stemming from neurodevelopmental failures. Various anomalies suggesting early abnormal brain development have been described in the entorhinal cortex (ENT) and ventral subiculum (SUB) of patients. This study examines the consequences of a neonatal transitory blockade of the left ENT or left SUB for latent inhibition-related dopamine responses in the anterior part of the dorsal striatum using in-vivo voltammetry in freely moving adult rats. Reversible inactivation of both structures in different animals was achieved by local microinjection of tetrodotoxin (TTX) at postnatal day 8. Results obtained during the retention session of a three-stage latent inhibition protocol showed that the functional neonatal disconnection of the ENT or SUB caused the behavioural latent inhibition expression in pre-exposed (PE)-TTX-conditioned adult rats to disappear. After postnatal inactivation of the SUB, PE-TTX-conditioned rats displayed a reversal of the latent inhibition-related striatal dopamine responses, whereas after neonatal blockade of the ENT, dopamine changes in PE-TTX-conditioned rats monitored in the anterior striatum were between those observed in PE-phosphate-buffered-saline-conditioned and non-PE-TTX-conditioned animals. These data suggest that neonatal functional inactivation of the SUB disrupts latent inhibition-related striatal dopamine responses in adult animals more than that of the ENT. They may help improve understanding of the pathophysiology of schizophrenia.
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Kinetics of Ozone Inactivation of Infectious Prion Protein
Ding, Ning; Price, Luke M.; Braithwaite, Shannon L.; Balachandran, Aru; Mitchell, Gordon; Belosevic, Miodrag
2013-01-01
The kinetics of ozone inactivation of infectious prion protein (PrPSc, scrapie 263K) was investigated in ozone-demand-free phosphate-buffered saline (PBS). Diluted infectious brain homogenates (IBH) (0.01%) were exposed to a predetermined ozone dose (10.8 ± 2.0 mg/liter) at three pHs (pH 4.4, 6.0, and 8.0) and two temperatures (4°C and 20°C). The inactivation of PrPSc was quantified by determining the in vitro destruction of PrPSc templating properties using the protein misfolding cyclic amplification (PMCA) assay and bioassay, which were shown to correlate well. The inactivation kinetics were characterized by both Chick-Watson (CW) and efficiency factor Hom (EFH) models. It was found that the EFH model fit the experimental data more appropriately. The efficacy of ozone inactivation of PrPSc was both pH and temperature dependent. Based on the EFH model, CT (disinfectant concentration multiplied by contact time) values were determined for 2-log10, 3-log10, and 4-log10 inactivation at the conditions under which they were achieved. Our results indicated that ozone is effective for prion inactivation in ozone-demand-free water and may be applied for the inactivation of infectious prion in prion-contaminated water and wastewater. PMID:23416994
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Achmon, Yigal; Fernández-Bayo, Jesús D; Hernandez, Katie; McCurry, Dlinka G; Harrold, Duff R; Su, Joey; Dahlquist-Willard, Ruth M; Stapleton, James J; VanderGheynst, Jean S; Simmons, Christopher W
2017-05-01
Biosolarization is a fumigation alternative that combines passive solar heating with amendment-driven soil microbial activity to temporarily create antagonistic soil conditions, such as elevated temperature and acidity, that can inactivate weed seeds and other pest propagules. The aim of this study was to use a mesocosm-based field trial to assess soil heating, pH, volatile fatty acid accumulation and weed seed inactivation during biosolarization. Biosolarization for 8 days using 2% mature green waste compost and 2 or 5% tomato processing residues in the soil resulted in accumulation of volatile fatty acids in the soil, particularly acetic acid, and >95% inactivation of Brassica nigra and Solanum nigrum seeds. Inactivation kinetics data showed that near complete weed seed inactivation in soil was achieved within the first 5 days of biosolarization. This was significantly greater than the inactivation achieved in control soils that were solar heated without amendment or were amended but not solar heated. The composition and concentration of organic matter amendments in soil significantly affected volatile fatty acid accumulation at various soil depths during biosolarization. Combining solar heating with organic matter amendment resulted in accelerated weed seed inactivation compared with either approach alone. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.
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Fisher, Michael B; Iriarte, Mercedes; Nelson, Kara L
2012-04-15
The use of alternative container materials and added oxidants accelerated the inactivation of MS2 coliphage and Escherichia coli and Enterococcus spp. bacteria during solar water disinfection (SODIS) trials. Specifically, bottles made from polypropylene copolymer (PPCO), a partially UVB-transparent plastic, resulted in three-log inactivation of these organisms in approximately half the time required for disinfection in bottles made from PET, polycarbonate, or Tritan(®), which absorb most UVB light. Furthermore, the addition of 125 mg/L sodium percarbonate in combination with either citric acid or copper plus ascorbate tended to accelerate inactivation by factors of 1.4-19. Finally, it was observed that the inactivation of E. coli and enterococci derived from local wastewater was far slower than the inactivation of laboratory-cultured E. coli and Enterococcus spp., while the inactivation of MS2 was slowest of all. These results highlight the importance of UVB in SODIS under certain conditions, and also the greater sunlight resistance of some viruses and of bacteria of fecal origin, as compared to the laboratory-cultured bacteria commonly used to model their inactivation. Furthermore, this study illustrates promising new avenues for accelerating the inactivation of bacteria and viruses by solar disinfection. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Inactivation of the Ventrolateral Orbitofrontal Cortex Impairs Flexible Use of Safety Signals.
Sarlitto, Mary C; Foilb, Allison R; Christianson, John P
2018-05-21
Survival depends on adaptation to shifting environmental risks and opportunities. Regarding risks, the mechanisms which permit acquisition, recall, and flexible use of aversive associations is poorly understood. Drawing on the evidence that the orbital frontal cortex is critical to integrating outcome expectancies with flexible appetitive behavioral responses, we hypothesized that OFC would contribute to behavioral flexibility within an aversive learning domain. We introduce a fear conditioning procedure in which adult male rats were presented with shock-paired conditioned stimulus (CS+) or a safety cue (CS-). In a recall test, rats exhibit greater freezing to the CS+ than the CS-. Temporary inactivation of the ventrolateral OFC with muscimol prior to conditioning did not affect later discrimination, but inactivation after learning and prior to recall impaired discrimination between safety and danger cues. This result complements prior research in the appetitive domain and suggests that the OFC plays a general role in behavioral flexibility regardless of the valence of the CS. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.
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Nagarkar-Jaiswal, Sonal; Manivannan, Sathiya N; Zuo, Zhongyuan; Bellen, Hugo J
2017-05-31
Here, we describe a novel method based on intronic MiMIC insertions described in Nagarkar-Jaiswal et al. (2015) to perform conditional gene inactivation in Drosophila . Mosaic analysis in Drosophila cannot be easily performed in post-mitotic cells. We therefore, therefore, developed Flip-Flop, a flippase -dependent in vivo cassette-inversion method that marks wild-type cells with the endogenous EGFP-tagged protein, whereas mutant cells are marked with mCherry upon inversion. We document the ease and usefulness of this strategy in differential tagging of wild-type and mutant cells in mosaics. We use this approach to phenotypically characterize the loss of SNF4Aγ , encoding the γ subunit of the AMP Kinase complex. The Flip-Flop method is efficient and reliable, and permits conditional gene inactivation based on both spatial and temporal cues, in a cell cycle-, and developmental stage-independent fashion, creating a platform for systematic screens of gene function in developing and adult flies with unprecedented detail.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Korich, D.G.; Mead, J.R.; Madore, M.S.
1990-05-01
Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 timesmore » more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water.« less
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Redox modulation of A-type K+ currents in pain-sensing dorsal root ganglion neurons.
Hsieh, Chi-Pan
2008-06-06
Redox modulation of fast inactivation has been described in certain cloned A-type voltage-gated K(+) (Kv) channels in expressing systems, but the effects remain to be demonstrated in native neurons. In this study, we examined the effects of cysteine-specific redox agents on the A-type K(+) currents in acutely dissociated small diameter dorsal root ganglion (DRG) neurons from rats. The fast inactivation of most A-type currents was markedly removed or slowed by the oxidizing agents 2,2'-dithio-bis(5-nitropyridine) (DTBNP) and chloramine-T. Dithiothreitol, a reducing agent for the disulfide bond, restored the inactivation. These results demonstrated that native A-type K(+) channels, probably Kv1.4, could switch the roles between inactivating and non-inactivating K(+) channels via redox regulation in pain-sensing DRG neurons. The A-type channels may play a role in adjusting pain sensitivity in response to peripheral redox conditions.
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A complete inactivation of the bacteria was achieved when using ENPHOSODIS under solar and visible light at three different NF-TiO2 catalyst concentrations. Under dark conditions, no difference in the bacteria count was observed and no inactivation of E. coli was observed when...
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USDA-ARS?s Scientific Manuscript database
High pressure inactivation of hepatitis A virus (HAV) within oysters bioaccumulated under simulated natural conditions to levels >106 PFU/oyster has been evaluated. Five min treatments at 20C were administered at 350, 375, and 400 MegaPascals (MPa). Shucked and whole-in-shell oysters were directly...
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Monochloramine Inactivation of Bacterial Select Agents▿
Rose, Laura J.; Rice, Eugene W.; Hodges, Lisa; Peterson, Alicia; Arduino, Matthew J.
2007-01-01
Seven species of bacterial select agents were tested for susceptibility to monochloramine. Under test conditions, the monochloramine routinely maintained in potable water would reduce six of the species by 2 orders of magnitude within 4.2 h. Bacillus anthracis spores would require up to 3.5 days for the same inactivation with monochloramine. PMID:17400782
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Oughli, Alaa A; Vélez, Marisela; Birrell, James A; Schuhmann, Wolfgang; Lubitz, Wolfgang; Plumeré, Nicolas; Rüdiger, Olaf
2018-06-08
In this work we present a viologen-modified electrode providing protection for hydrogenases against high potential inactivation. Hydrogenases, including O2-tolerant classes, suffer from reversible inactivation upon applying high potentials, which limits their use in biofuel cells to certain conditions. Our previously reported protection strategy based on the integration of hydrogenase into redox matrices enabled the use of these biocatalysts in biofuel cells even under anode limiting conditions. However, mediated catalysis required application of an overpotential to drive the reaction, and this translates into a power loss in a biofuel cell. In the present work, the enzyme is adsorbed on top of a covalently-attached viologen layer which leads to mixed, direct and mediated, electron transfer processes; at low overpotentials, the direct electron transfer process generates a catalytic current, while the mediated electron transfer through the viologens at higher potentials generates a redox buffer that prevents oxidative inactivation of the enzyme. Consequently, the enzyme starts the catalysis at no overpotential with viologen self-activated protection at high potentials.
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Walkup, Ward G.; Washburn, Lorraine; Sweredoski, Michael J.; Carlisle, Holly J.; Graham, Robert L.; Hess, Sonja; Kennedy, Mary B.
2015-01-01
synGAP is a neuron-specific Ras and Rap GTPase-activating protein (GAP) found in high concentrations in the postsynaptic density (PSD) fraction from the mammalian forebrain. We have previously shown that, in situ in the PSD fraction or in recombinant form in Sf9 cell membranes, synGAP is phosphorylated by Ca2+/calmodulin-dependent protein kinase II (CaMKII), another prominent component of the PSD. Here, we show that recombinant synGAP (r-synGAP), lacking 102 residues at the N terminus, can be purified in soluble form and is phosphorylated by cyclin-dependent kinase 5 (CDK5) as well as by CaMKII. Phosphorylation of r-synGAP by CaMKII increases its HRas GAP activity by 25% and its Rap1 GAP activity by 76%. Conversely, phosphorylation by CDK5 increases r-synGAP's HRas GAP activity by 98% and its Rap1 GAP activity by 20%. Thus, phosphorylation by both kinases increases synGAP activity; CaMKII shifts the relative GAP activity toward inactivation of Rap1, and CDK5 shifts the relative activity toward inactivation of HRas. GAP activity toward Rap2 is not altered by phosphorylation by either kinase. CDK5 phosphorylates synGAP primarily at two sites, Ser-773 and Ser-802. Phosphorylation at Ser-773 inhibits r-synGAP activity, and phosphorylation at Ser-802 increases it. However, the net effect of concurrent phosphorylation of both sites, Ser-773 and Ser-802, is an increase in GAP activity. synGAP is phosphorylated at Ser-773 and Ser-802 in the PSD fraction, and its phosphorylation by CDK5 and CaMKII is differentially regulated by activation of NMDA-type glutamate receptors in cultured neurons. PMID:25533468
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The use of chlorine dioxide for the inactivation of copepod zooplankton in drinking water treatment.
Lin, Tao; Chen, Wei; Cai, Bo
2014-01-01
The presence of zooplankton in drinking water treatment system may cause a negative effect on the aesthetic value of drinking water and may also increase the threat to human health due to they being the carriers of bacteria. Very little research has been done on the effects of copepod inactivation and the mechanisms involved in this process. In a series of bench-scale experiments we used a response surface method to assess the sensitivity of copepod to inactivation when chlorine dioxide (ClO₂) was used as a disinfectant. We also assessed the effects of the ClO₂dosage, exposure time, organic matter concentration and temperature. Results indicated that the inactivation rate improved with increasing dosage, exposure time and temperature, whereas it decreased with increasing organic matter concentration. Copepod inactivation was more sensitive to the ClO₂dose than that to the exposure time, while being maintained at the same Ct-value conditions. The activation energy at different temperatures revealed that the inactivation of copepods with ClO₂was temperature-dependent. The presence of organic matter resulted in a lower available dose as well as a shorter available exposure time, which resulted in a decrease in inactivation efficiency.
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Silverman, Andrea I; Nelson, Kara L
2016-11-15
Models that predict sunlight inactivation rates of bacteria are valuable tools for predicting the fate of pathogens in recreational waters and designing natural wastewater treatment systems to meet disinfection goals. We developed biological weighting function (BWF)-based numerical models to estimate the endogenous sunlight inactivation rates of E. coli and enterococci. BWF-based models allow the prediction of inactivation rates under a range of environmental conditions that shift the magnitude or spectral distribution of sunlight irradiance (e.g., different times, latitudes, water absorbances, depth). Separate models were developed for laboratory strain bacteria cultured in the laboratory and indigenous organisms concentrated directly from wastewater. Wastewater bacteria were found to be 5-7 times less susceptible to full-spectrum simulated sunlight than the laboratory bacteria, highlighting the importance of conducting experiments with bacteria sourced directly from wastewater. The inactivation rate models fit experimental data well and were successful in predicting the inactivation rates of wastewater E. coli and enterococci measured in clear marine water by researchers from a different laboratory. Additional research is recommended to develop strategies to account for the effects of elevated water pH on predicted inactivation rates.
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Thermal Inactivation of Feline Calicivirus in Pet Food Processing.
Haines, J; Patel, M; Knight, A I; Corley, D; Gibson, G; Schaaf, J; Moulin, J; Zuber, S
2015-12-01
Extrusion is the most common manufacturing process used to produce heat-treated dry dog and cat food (pet food) for domestic use and international trade. Due to reoccurring outbreaks of notifiable terrestrial animal diseases and their impact on international trade, experiments were undertaken to demonstrate the effectiveness of heat-treated extruded pet food on virus inactivation. The impact of extrusion processing in a pet food matrix on virus inactivation has not been previously reported and very few inactivation studies have examined the thermal inactivation of viruses in complex food matrices. The feline calicivirus vaccine strain FCV F-9 was used as a surrogate model RNA virus pathogen. Small-scale heat inactivation experiments using animal-derived pet food raw materials showed that a > 4 log10 reduction (log10 R) in infectivity occurred at 70 °C prior to reaching the minimum extrusion manufacturing operating temperature of 100 °C. As anticipated, small-scale pressure studies at extrusion pressure (1.6 MPa) showed no apparent effect on FCV F-9 inactivation. Additionally, FCV F-9 was shown not to survive the acidic conditions used to produce pet food palatants of animal origin that are typically used as a coating after the extrusion process.
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Sánchez-Camacho, Cristina; Ortega, Juan Alberto; Ocaña, Inmaculada; Alcántara, Soledad; Bovolenta, Paola
2011-05-01
Guidepost cells are essential structures for the establishment of major axonal tracts. How these structures are specified and acquire their axon guidance properties is still poorly understood. Here, we show that in mouse embryos appropriate levels of Bone Morphogenetic Protein 7 (Bmp7), a member of the TGF-β superfamily of secreted proteins, are required for the correct development of the glial wedge, the indusium griseum, and the subcallosal sling, three groups of cells that act as guidepost cells for growing callosal axons. Bmp7 is expressed in the region occupied by these structures and its genetic inactivation in mouse embryos caused a marked reduction and disorganization of these cell populations. On the contrary, infusion of recombinant Bmp7 in the developing forebrain induced their premature differentiation. In both cases, changes were associated with the disruption of callosal axon growth and, in most animals fibers did not cross the midline forming typical Probst bundles. Addition of Bmp7 to cortical explants did not modify the extent of their outgrowth nor their directionality, when explants were exposed to a focalized source of the protein. Together, these results indicate that Bmp7 is indirectly required for corpus callosum formation by controlling the timely differentiation of its guidepost cells. Copyright © 2010 Wiley Periodicals, Inc.
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Molecular Regulation of DNA Damage-Induced Apoptosis in Neurons of Cerebral Cortex
Liu, Zhiping; Pipino, Jacqueline; Chestnut, Barry; Landek, Melissa A.
2009-01-01
Cerebral cortical neuron degeneration occurs in brain disorders manifesting throughout life, but the mechanisms are understood poorly. We used cultured embryonic mouse cortical neurons and an in vivo mouse model to study mechanisms of DNA damaged-induced apoptosis in immature and differentiated neurons. p53 drives apoptosis of immature and differentiated cortical neurons through its rapid and prominent activation stimulated by DNA strand breaks induced by topoisomerase-I and -II inhibition. Blocking p53-DNA transactivation with α-pifithrin protects immature neurons; blocking p53-mitochondrial functions with μ-pifithrin protects differentiated neurons. Mitochondrial death proteins are upregulated in apoptotic immature and differentiated neurons and have nonredundant proapoptotic functions; Bak is more dominant than Bax in differentiated neurons. p53 phosphorylation is mediated by ataxia telangiectasia mutated (ATM) kinase. ATM inactivation is antiapoptotic, particularly in differentiated neurons, whereas inhibition of c-Abl protects immature neurons but not differentiated neurons. Cell death protein expression patterns in mouse forebrain are mostly similar to cultured neurons. DNA damage induces prominent p53 activation and apoptosis in cerebral cortex in vivo. Thus, DNA strand breaks in cortical neurons induce rapid p53-mediated apoptosis through actions of upstream ATM and c-Abl kinases and downstream mitochondrial death proteins. This molecular network operates through variations depending on neuron maturity. PMID:18820287
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Obál, F; Benedek, G; Szikszay, M; Obál, F
1979-01-01
A study was made of the effects of high mesencephalic transection (cerveau isolé) and low doses of pentobarbital on the cortical synchronizations elicited in acute immobilized cats by (a) low frequency stimulation of the lateral hypothalamus (HL) and nucleus ventralis anterior thalami (VA) and (b) by low and high frequency stimulation of the laterobasal preoptic region (RPO) and olfactory tubercle (TbOf). The results obtained were as follows: (1) The synchronizations induced by basal forebrain stimulations were found to survive in acute cerveau isolé cats, moreover, even a facilitation of the synchronizing effect were observed. (2) A gradual facilitation was observed upon TbOf and RPO stimulation, while in the case of VA and HL stimulations, the facilitation appeared immediately after the transection. (3) Low doses of pentobarbital depressed the cortical effects of TbOf stimulation, while an increase of the synchronizing effect of low frequency VA and HL stimulation was found. The observations suggested that (i) the synchronizing mechanism in the ventral part of the basal forebrain (RPO and TbOf) differs from that of the thalamus and HL; (ii) the basal forebrain synchronizing mechanism is effective without the contribution of the brain stem; (iii) the mechanism responsible for the synchronizing effect of low frequency HL stimulation is similar as that described for the thalamus.
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Contraction and stress-dependent growth shape the forebrain of the early chicken embryo.
Garcia, Kara E; Okamoto, Ruth J; Bayly, Philip V; Taber, Larry A
2017-01-01
During early vertebrate development, local constrictions, or sulci, form to divide the forebrain into the diencephalon, telencephalon, and optic vesicles. These partitions are maintained and exaggerated as the brain tube inflates, grows, and bends. Combining quantitative experiments on chick embryos with computational modeling, we investigated the biophysical mechanisms that drive these changes in brain shape. Chemical perturbations of contractility indicated that actomyosin contraction plays a major role in the creation of initial constrictions (Hamburger-Hamilton stages HH11-12), and fluorescent staining revealed that F-actin is circumferentially aligned at all constrictions. A finite element model based on these findings shows that the observed shape changes are consistent with circumferential contraction in these regions. To explain why sulci continue to deepen as the forebrain expands (HH12-20), we speculate that growth depends on wall stress. This idea was examined by including stress-dependent growth in a model with cerebrospinal fluid pressure and bending (cephalic flexure). The results given by the model agree with observed morphological changes that occur in the brain tube under normal and reduced eCSF pressure, quantitative measurements of relative sulcal depth versus time, and previously published patterns of cell proliferation. Taken together, our results support a biphasic mechanism for forebrain morphogenesis consisting of differential contractility (early) and stress-dependent growth (late). Copyright © 2016 Elsevier Ltd. All rights reserved.
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Rapid Effects of Hearing Song on Catecholaminergic Activity in the Songbird Auditory Pathway
Matragrano, Lisa L.; Beaulieu, Michaël; Phillip, Jessica O.; Rae, Ali I.; Sanford, Sara E.; Sockman, Keith W.; Maney, Donna L.
2012-01-01
Catecholaminergic (CA) neurons innervate sensory areas and affect the processing of sensory signals. For example, in birds, CA fibers innervate the auditory pathway at each level, including the midbrain, thalamus, and forebrain. We have shown previously that in female European starlings, CA activity in the auditory forebrain can be enhanced by exposure to attractive male song for one week. It is not known, however, whether hearing song can initiate that activity more rapidly. Here, we exposed estrogen-primed, female white-throated sparrows to conspecific male song and looked for evidence of rapid synthesis of catecholamines in auditory areas. In one hemisphere of the brain, we used immunohistochemistry to detect the phosphorylation of tyrosine hydroxylase (TH), a rate-limiting enzyme in the CA synthetic pathway. We found that immunoreactivity for TH phosphorylated at serine 40 increased dramatically in the auditory forebrain, but not the auditory thalamus and midbrain, after 15 min of song exposure. In the other hemisphere, we used high pressure liquid chromatography to measure catecholamines and their metabolites. We found that two dopamine metabolites, dihydroxyphenylacetic acid and homovanillic acid, increased in the auditory forebrain but not the auditory midbrain after 30 min of exposure to conspecific song. Our results are consistent with the hypothesis that exposure to a behaviorally relevant auditory stimulus rapidly induces CA activity, which may play a role in auditory responses. PMID:22724011
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Mast cells in the sheep, hedgehog and rat forebrain
MICHALOUDI, HELEN C.; PAPADOPOULOS, GEORGIOS C.
1999-01-01
The study was designed to reveal the distribution of various mast cell types in the forebrain of the adult sheep, hedgehog and rat. Based on their histochemical and immunocytochemical characteristics, mast cells were categorised as (1) connective tissue-type mast cells, staining metachromatically purple with the toluidine blue method, or pale red with the Alcian blue/safranin method, (2) mucosal-type or immature mast cells staining blue with the Alcian blue/safranin method and (3) serotonin immunopositive mast cells. All 3 types of brain mast cells in all species studied were located in both white and grey matter, often associated with intraparenchymal blood vessels. Their distribution pattern exhibited interspecies differences, while their number varied considerably not only between species but also between individuals of each species. A distributional left-right asymmetry, with more cells present on the left side, was observed in all species studied but it was most prominent in the sheep brain. In the sheep, mast cells were abundantly distributed in forebrain areas, while in the hedgehog and the rat forebrain, mast cells were less widely distributed and were relatively or substantially fewer in number respectively. A limited number of brain mast cells, in all 3 species, but primarily in the rat, were found to react both immunocytochemically to 5-HT antibody and histochemically with Alcian blue/safranin staining. PMID:10634696
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Giardino, L; Giuliani, A; Battaglia, A; Carfagna, N; Aloe, L; Calza', L
2002-01-01
The aging brain is characterized by selective neurochemical changes involving several neural populations. A deficit in the cholinergic system of the basal forebrain is thought to contribute to the development of cognitive symptoms of dementia. Attempts to prevent age-associated cholinergic vulnerability and deterioration therefore represent a crucial point for pharmacotherapy in the elderly. In this paper we provide evidence for the protective effect of nicergoline (Sermion) on the degeneration of cholinergic neurons induced by nerve growth factor deprivation. Nerve growth factor deprivation was induced by colchicine administration in rats 13 and 18 months old. Colchicine induces a rapid and substantial down-regulation of choline acetyltransferase messenger RNA level in the basal forebrain in untreated adult, middle-aged and old rats. Colchicine failed to cause these effects in old rats treated for 120 days with nicergoline 10 mg/kg/day, orally. Moreover, a concomitant increase of both nerve growth factor and brain-derived neurotrophic factor content was measured in the basal forebrain of old, nicergoline-treated rats. Additionally, the level of messenger RNA for the brain isoform of nitric oxide synthase in neurons of the basal forebrain was also increased in these animals. Based on the present findings, nicergoline proved to be an effective drug for preventing neuronal vulnerability due to experimentally induced nerve growth factor deprivation.
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Gravemann, U; Handke, W; Sumian, C; Alvarez, I; Reichenberg, S; Müller, T H; Seltsam, A
2018-02-27
Photodynamic treatment using methylene blue (MB) and visible light is in routine use for pathogen inactivation of human plasma in different countries. Ambient and product temperature conditions for human plasma during production may vary between production sites. The influence of different temperature conditions on virus inactivation capacity and plasma quality of the THERAFLEX MB-Plasma procedure was investigated in this study. Plasma units equilibrated to 5 ± 2°C, room temperature (22 ± 2°C) or 30 ± 2°C were treated with MB/light and comparatively assessed for the inactivation capacity for three different viruses, concentrations of MB and its photoproducts, activity of various plasma coagulation factors and clotting time. Reduced solubility of the MB pill was observed at 5 ± 2°C. Photocatalytic degradation of MB increased with increasing temperature, and the greatest formation of photoproducts (mainly azure B) occurred at 30 ± 2°C. Inactivation of suid herpesvirus, bovine viral diarrhoea virus and vesicular stomatitis virus was significantly lower at 5 ± 2°C than at higher temperatures. MB/light treatment affected clotting times and the activity of almost all investigated plasma proteins. Factor VIII (-17·7 ± 8·3%, 22 ± 2°C) and fibrinogen (-14·4 ± 16·4%, 22 ± 2°C) showed the highest decreases in activity. Increasing plasma temperatures resulted in greater changes in clotting time and higher losses of plasma coagulation factor activity. Temperature conditions for THERAFLEX MB-Plasma treatment must be carefully controlled to assure uniform quality of pathogen-reduced plasma in routine production. Inactivation of cooled plasma is not recommended. © 2018 International Society of Blood Transfusion.
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2012-01-01
Background Controlling fish disease is one of the major concerns in contemporary aquaculture. The use of antibiotics or chemical disinfection cannot provide a healthy aquaculture system without residual effects. Water quality is also important in determining the success or failure of fish production. Several solar photocatalytic reactors have been used to treat drinking water or waste water without leaving chemical residues. This study has investigated the impact of several key aspects of water quality on the inactivation of the pathogenic bacterium Aeromonas hydrophila using a pilot-scale thin-film fixed-bed reactor (TFFBR) system. Results The level of inactivation of Aeromonas hydrophila ATCC 35654 was determined using a TFFBR with a photocatalytic area of 0.47 m2 under the influence of various water quality variables (pH, conductivity, turbidity and colour) under high solar irradiance conditions (980–1100 W m-2), at a flow rate of 4.8 L h-1 through the reactor. Bacterial enumeration were obtained through conventional plate count using trypticase soy agar media, cultured in conventional aerobic conditions to detect healthy cells and under ROS-neutralised conditions to detect both healthy and sub-lethally injured (oxygen-sensitive) cells. The results showed that turbidity has a major influence on solar photocatalytic inactivation of A. hydrophila. Humic acids appear to decrease TiO2 effectiveness under full sunlight and reduce microbial inactivation. pH in the range 7–9 and salinity both have no major effect on the extent of photoinactivation or sub-lethal injury. Conclusions This study demonstrates the effectiveness of the TFFBR in the inactivation of Aeromonas hydrophila under the influence of several water quality variables at high solar irradiance, providing an opportunity for the application of solar photocatalysis in aquaculture systems, as long as turbidity remains low. PMID:23194331
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Inactivation of the Prelimbic Cortex Attenuates Context-Dependent Operant Responding.
Trask, Sydney; Shipman, Megan L; Green, John T; Bouton, Mark E
2017-03-01
Operant responding in rats provides an analog to voluntary behavior in humans and is used to study maladaptive behaviors, such as overeating, drug taking, or relapse. In renewal paradigms, extinguished behavior recovers when tested outside the context where extinction was learned. Inactivation of the prelimbic (PL) region of the medial prefrontal cortex by baclofen/muscimol (B/M) during testing attenuates renewal when tested in the original acquisition context after extinction in another context (ABA renewal). Two experiments tested the hypothesis that the PL is important in context-dependent responding learned during conditioning. In the first, rats learned to lever-press for a sucrose-pellet reward. Following acquisition, animals were infused with either B/M or vehicle in the PL and tested in the acquisition context (A) and in a different context (B). All rats showed a decrement in responding when switched from Context A to Context B, but PL inactivation decreased responding only in Context A. Experiment 2a examined the effects of PL inactivation on ABC renewal in the same rats. Here, following reacquisition of the response, responding was extinguished in a new context (C). Following infusions of B/M or vehicle in the PL, responding was tested in Context C and another new context (D). The rats exhibited ACD renewal regardless of PL inactivation. Experiment 2b demonstrated that PL inactivation attenuated the ABA renewal effect in the same animals, replicating earlier results and demonstrating that cannulae were still functional. The results suggest that, rather than attenuating renewal generally, PL inactivation specifically affects ABA renewal by reducing responding in the conditioning context. SIGNIFICANCE STATEMENT Extinguished operant behavior can recover ("renew") when tested outside the extinction context. This suggests that behaviors, such as overeating or drug taking, might be especially prone to relapse following treatment. In rats, inactivation of the prelimbic cortex (PL) attenuates renewal. However, we report that PL inactivation after training attenuates responding in the context in which responding was acquired, but not in another one. A similar inactivation has no impact on renewal when testing occurs in a new, rather than the original, context following extinction. The PL thus has a more specific role in controlling contextually dependent operant behavior than has been previously reported. Copyright © 2017 the authors 0270-6474/17/372317-08$15.00/0.
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Inactivation of the Prelimbic Cortex Attenuates Context-Dependent Operant Responding
Shipman, Megan L.; Bouton, Mark E.
2017-01-01
Operant responding in rats provides an analog to voluntary behavior in humans and is used to study maladaptive behaviors, such as overeating, drug taking, or relapse. In renewal paradigms, extinguished behavior recovers when tested outside the context where extinction was learned. Inactivation of the prelimbic (PL) region of the medial prefrontal cortex by baclofen/muscimol (B/M) during testing attenuates renewal when tested in the original acquisition context after extinction in another context (ABA renewal). Two experiments tested the hypothesis that the PL is important in context-dependent responding learned during conditioning. In the first, rats learned to lever-press for a sucrose-pellet reward. Following acquisition, animals were infused with either B/M or vehicle in the PL and tested in the acquisition context (A) and in a different context (B). All rats showed a decrement in responding when switched from Context A to Context B, but PL inactivation decreased responding only in Context A. Experiment 2a examined the effects of PL inactivation on ABC renewal in the same rats. Here, following reacquisition of the response, responding was extinguished in a new context (C). Following infusions of B/M or vehicle in the PL, responding was tested in Context C and another new context (D). The rats exhibited ACD renewal regardless of PL inactivation. Experiment 2b demonstrated that PL inactivation attenuated the ABA renewal effect in the same animals, replicating earlier results and demonstrating that cannulae were still functional. The results suggest that, rather than attenuating renewal generally, PL inactivation specifically affects ABA renewal by reducing responding in the conditioning context. SIGNIFICANCE STATEMENT Extinguished operant behavior can recover (“renew”) when tested outside the extinction context. This suggests that behaviors, such as overeating or drug taking, might be especially prone to relapse following treatment. In rats, inactivation of the prelimbic cortex (PL) attenuates renewal. However, we report that PL inactivation after training attenuates responding in the context in which responding was acquired, but not in another one. A similar inactivation has no impact on renewal when testing occurs in a new, rather than the original, context following extinction. The PL thus has a more specific role in controlling contextually dependent operant behavior than has been previously reported. PMID:28137970
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Cerebral xanthomatosis in three green water dragons (Physignathus cocincinus).
Kummrow, Maya S; Berkvens, Charlene N; Paré, Jean A; Smith, Dale A
2010-03-01
Cerebral xanthomatosis was diagnosed in three female green water dragons (Physignathus cocincinus), all of which presented with progressive neurologic signs. No antemortem evidence for xanthomatosis was identified, but on postmortem examination cholesterol granulomas, composed of cholesterol clefts surrounded by macrophages and multinucleated giant cells, were found in the forebrain of each animal and were associated with significant displacement and pressure on the adjacent brain. Although the cause of xanthomatosis in these animals is unknown, nutrition and trauma may be involved in the pathogenesis of this condition. Cerebrum, cholesterol, green water dragon, Physignathus cocincinus, xanthoma.
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Felker, Daniel L.; Burggraf, Larry W.
2014-01-01
Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating. PMID:24375142
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[Effect of various factors on ozone inactivating Giardia in water].
Ran, Zhi-Lin; Li, Shao-Feng; Huang, Jun-Li; Yuan, Yi-Xing; Cui, Chong-Wei
2010-06-01
In order to study the effect of O3 inactivating Giardia in water, different factors (CT value, pH, temperature, turbidity, organic content and inorganic ions) which might influence the inactivation were investigated by using fluorescence staining method. The results indicated that the whole process of O3 inactivating Giardia could be divided into two periods, the inactivated rate in log phase was significantly faster than it in the slow phase [k1 = (5.64 +/- 0.023) x 10(-1) mg x min, k2 = (2.72 +/- 0.002) x 10(-2) mg x min, k1 > k2]. When the turbidity was 0.1 to 20. 0NTU, temperature was 5 to 35 degrees C, pH was 6.0 to 9.0, HA content was 0.5 to 10.0 mg/L, the turbidity was lower, the higher inactivating ratio could be received. With the increasing of temperature, the inactivating effect was decreased. The ability of O3 inactivating Giardia was stronger under acidic condition than it was in alkali circumstance. When the reaction system contained higher concentration of organics, the competition reaction might take place between Giardia and organics with O3, which might reduce inactivation ratio. The sequence of affecting disinfectant ability of O3 was NO3- > None > SO4(2-) > HCO3-, while inorganic cations (Ca2+, Mg2+ and Cu2+) promoted the inactive reaction to a certain extent. If the CT value of O3 was more than 15.0 min x mg/L, the ratio of inactivation could exceed 99.0% during disinfecting drinking water.
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Heisenberg, C P; Brennan, C; Wilson, S W
1999-05-01
During the development of the zebrafish nervous system both noi, a zebrafish pax2 homolog, and ace, a zebrafish fgf8 homolog, are required for development of the midbrain and cerebellum. Here we describe a dominant mutation, aussicht (aus), in which the expression of noi and ace is upregulated. In aus mutant embryos, ace is upregulated at many sites in the embryo, while noi expression is only upregulated in regions of the forebrain and midbrain which also express ace. Subsequent to the alterations in noi and ace expression, aus mutants exhibit defects in the differentiation of the forebrain, midbrain and eyes. Within the forebrain, the formation of the anterior and postoptic commissures is delayed and the expression of markers within the pretectal area is reduced. Within the midbrain, En and wnt1 expression is expanded. In heterozygous aus embryos, there is ectopic outgrowth of neural retina in the temporal half of the eyes, whereas in putative homozygous aus embryos, the ventral retina is reduced and the pigmented retinal epithelium is expanded towards the midline. The observation that aus mutant embryos exhibit widespread upregulation of ace raised the possibility that aus might represent an allele of the ace gene itself. However, by crossing carriers for both aus and ace, we were able to generate homozygous ace mutant embryos that also exhibited the aus phenotype. This indicated that aus is not tightly linked to ace and is unlikely to be a mutation directly affecting the ace locus. However, increased Ace activity may underly many aspects of the aus phenotype and we show that the upregulation of noi in the forebrain of aus mutants is partially dependent upon functional Ace activity. Conversely, increased ace expression in the forebrain of aus mutants is not dependent upon functional Noi activity. We conclude that aus represents a mutation involving a locus normally required for the regulation of ace expression during embryogenesis.
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Song exposure regulates known and novel microRNAs in the zebra finch auditory forebrain
2011-01-01
Background In an important model for neuroscience, songbirds learn to discriminate songs they hear during tape-recorded playbacks, as demonstrated by song-specific habituation of both behavioral and neurogenomic responses in the auditory forebrain. We hypothesized that microRNAs (miRNAs or miRs) may participate in the changing pattern of gene expression induced by song exposure. To test this, we used massively parallel Illumina sequencing to analyse small RNAs from auditory forebrain of adult zebra finches exposed to tape-recorded birdsong or silence. Results In the auditory forebrain, we identified 121 known miRNAs conserved in other vertebrates. We also identified 34 novel miRNAs that do not align to human or chicken genomes. Five conserved miRNAs showed significant and consistent changes in copy number after song exposure across three biological replications of the song-silence comparison, with two increasing (tgu-miR-25, tgu-miR-192) and three decreasing (tgu-miR-92, tgu-miR-124, tgu-miR-129-5p). We also detected a locus on the Z sex chromosome that produces three different novel miRNAs, with supporting evidence from Northern blot and TaqMan qPCR assays for differential expression in males and females and in response to song playbacks. One of these, tgu-miR-2954-3p, is predicted (by TargetScan) to regulate eight song-responsive mRNAs that all have functions in cellular proliferation and neuronal differentiation. Conclusions The experience of hearing another bird singing alters the profile of miRNAs in the auditory forebrain of zebra finches. The response involves both known conserved miRNAs and novel miRNAs described so far only in the zebra finch, including a novel sex-linked, song-responsive miRNA. These results indicate that miRNAs are likely to contribute to the unique behavioural biology of learned song communication in songbirds. PMID:21627805
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Ventskovska, Olena; Porkka-Heiskanen, Tarja; Karpova, Nina N
2015-04-01
Brain-derived neurotrophic factor (Bdnf) regulates neuronal plasticity, slow wave activity and sleep homeostasis. Environmental stimuli control Bdnf expression through epigenetic mechanisms, but there are no data on epigenetic regulation of Bdnf by sleep or sleep deprivation. Here we investigated whether 5-methylcytosine (5mC) DNA modification at Bdnf promoters p1, p4 and p9 influences Bdnf1, Bdnf4 and Bdnf9a expression during the normal inactive phase or after sleep deprivation (SD) (3, 6 and 12 h, end-times being ZT3, ZT6 and ZT12) in rats in two brain areas involved in sleep regulation, the basal forebrain and cortex. We found a daytime variation in cortical Bdnf expression: Bdnf1 expression was highest at ZT6 and Bdnf4 lowest at ZT12. Such variation was not observed in the basal forebrain. Also Bdnf p1 and p9 methylation levels differed only in the cortex, while Bdnf p4 methylation did not vary in either area. Factorial analysis revealed that sleep deprivation significantly induced Bdnf1 and Bdnf4 with the similar pattern for Bdnf9a in both basal forebrain and cortex; 12 h of sleep deprivation decreased 5mC levels at the cortical Bdnf p4 and p9. Regression analysis between the 5mC promoter levels and the corresponding Bdnf transcript expression revealed significant negative correlations for the basal forebrain Bdnf1 and cortical Bdnf9a transcripts in only non-deprived rats, while these correlations were lost after sleep deprivation. Our results suggest that Bdnf transcription during the light phase of undisturbed sleep-wake cycle but not after SD is regulated at least partially by brain site-specific DNA methylation. © 2014 European Sleep Research Society.
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Dunlop, P S M; Ciavola, M; Rizzo, L; Byrne, J A
2011-11-01
Solar disinfection (SODIS) of Escherichia coli suspensions in low-density polyethylene bag reactors was investigated as a low-cost disinfection method suitable for application in developing countries. The efficiency of a range of SODIS reactor configurations was examined (single skin (SS), double skin, black-backed single skin, silver-backed single skin (SBSS) and composite-backed single skin) using E. coli suspended in model and real surface water. Titanium dioxide was added to the reactors to improve the efficiency of the SODIS process. The effect of turbidity was also assessed. In addition to viable counts, E. coli injury was characterised through spread-plate analysis using selective and non-selective media. The optimal reactor configuration was determined to be the SBSS bag (t(50)=9.0min) demonstrating the importance of UVA photons, as opposed to infrared in the SODIS disinfection mechanism. Complete inactivation (6.5-log) was achieved in the presence of turbidity (50NTU) using the SBSS bag within 180min simulated solar exposure. The addition of titanium dioxide (0.025gL(-1)) significantly enhanced E. coli inactivation in the SS reactor, with 6-log inactivation observed within 90min simulated solar exposure. During the early stages of both SODIS and photocatalytic disinfection, injured E. coli were detected; however, irreversible injury was caused and re-growth was not observed. Experiments under solar conditions were undertaken with total inactivation (6.5-log) observed in the SS reactor within 240min, incomplete inactivation (4-log) was observed in SODIS bottles exposed to the same solar conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Oliviero, T; Verkerk, R; Van Boekel, M A J S; Dekker, M
2014-11-15
Broccoli belongs to the Brassicaceae plant family consisting of widely eaten vegetables containing high concentrations of glucosinolates. Enzymatic hydrolysis of glucosinolates by endogenous myrosinase (MYR) can form isothiocyanates with health-promoting activities. The effect of water content (WC) and temperature on MYR inactivation in broccoli was investigated. Broccoli was freeze dried obtaining batches with WC between 10% and 90% (aw from 0.10 to 0.96). These samples were incubated for various times at different temperatures (40-70°C) and MYR activity was measured. The initial MYR inactivation rates were estimated by the first-order reaction kinetic model. MYR inactivation rate constants were lower in the driest samples (10% WC) at all studied temperatures. Samples with 67% and 90% WC showed initial inactivation rate constants all in the same order of magnitude. Samples with 31% WC showed intermediate initial inactivation rate constants. These results are useful to optimise the conditions of drying processes to produce dried broccoli with optimal MYR retention for human health. Copyright © 2014 Elsevier Ltd. All rights reserved.
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2013-01-01
Background Increasing evidence indicates that neuroinflammation is a critical factor contributing to the progression of various neurodegenerative diseases. The IKK/NF-κB signalling system is a central regulator of inflammation, but it also affects neuronal survival and differentiation. A complex interplay between different CNS resident cells and infiltrating immune cells, which produce and respond to various inflammatory mediators, determines whether neuroinflammation is beneficial or detrimental. The IKK/NF-κB system is involved in both production of and responses to these mediators, although the precise contribution depends on the cell type as well as the cellular context, and is only partially understood. Here we investigated the specific contribution of neuronal IKK/NF-κB signalling on the regulation of neuroinflammatory processes and its consequences. To address this issue, we established and analysed a conditional gain-of-function mouse model that expresses a constitutively active allele of IKK2 in principal forebrain neurons (IKK2nCA). Proinflammatory gene and growth factor expression, histopathology, microgliosis, astrogliosis, immune cell infiltration and spatial learning were assessed at different timepoints after persistent canonical IKK2/NF-κB activation. Results In contrast to other cell types and organ systems, chronic IKK2/NF-κB signalling in forebrain neurons of adult IKK2nCA animals did not cause a full-blown inflammatory response including infiltration of immune cells. Instead, we found a selective inflammatory response in the dentate gyrus characterized by astrogliosis, microgliosis and Tnf-α upregulation. Furthermore, downregulation of the neurotrophic factor Bdnf correlated with a selective and progressive atrophy of the dentate gyrus and a decline in hippocampus-dependent spatial learning. Neuronal degeneration was associated with increased Fluoro-jade staining, but lacked activation of apoptosis. Remarkably, neuronal loss could be partially reversed when chronic IKK2/NF-κB signalling was turned off and Bdnf expression was restored. Conclusion Our results demonstrate that persistent IKK2/NF-κB signalling in forebrain neurons does not induce overall neuroinflammation, but elicits a selective inflammatory response in the dentate gyrus accompanied by decreased neuronal survival and impaired learning and memory. Our findings further suggest that chronic activation of neuronal IKK2/NF-κB signalling, possibly as a consequence of neuroinflammatory conditions, is able to induce apoptosis-independent neurodegeneration via paracrine suppression of Bdnf synthesis. PMID:24119288
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Orbitofrontal participation in sign- and goal-tracking conditioned responses: Effects of nicotine.
Stringfield, Sierra J; Palmatier, Matthew I; Boettiger, Charlotte A; Robinson, Donita L
2017-04-01
Pavlovian conditioned stimuli can acquire incentive motivational properties, and this phenomenon can be measured in animals using Pavlovian conditioned approach behavior. Drugs of abuse can influence the expression of this behavior, and nicotine in particular exhibits incentive amplifying effects. Both conditioned approach behavior and drug abuse rely on overlapping corticolimbic circuitry. We hypothesize that the orbitofrontal cortex (OFC) regulates conditioned approach, and that one site of nicotine action is in the OFC where it reduces cortical output. To test this, we repeatedly exposed rats to 0.4 mg/kg nicotine (s.c.) during training and then pharmacologically inactivated the lateral OFC or performed in vivo electrophysiological recordings of lateral OFC neurons in the presence or absence of nicotine. In Experiment 1, animals were trained in a Pavlovian conditioning paradigm and behavior was evaluated after inactivation of the OFC by microinfusion of the GABA agonists baclofen and muscimol. In Experiment 2, we monitored phasic firing of OFC neurons during Pavlovian conditioning sessions. Nicotine reliably enhanced conditioned responding to the conditioned cue, and inactivation of the OFC reduced conditioned responding, especially the sign-tracking response. OFC neurons exhibited phasic excitations to cue presentation and during goal tracking, and nicotine acutely blunted this phasic neuronal firing. When nicotine was withheld, both conditioned responding and phasic firing in the OFC returned to the level of controls. These results suggest that the OFC is recruited for the expression of conditioned responses, and that nicotine acutely influences this behavior by reducing phasic firing in the OFC. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Luine, V N
1985-08-01
Administration of estradiol to gonadectomized female, but not male rats, is associated with increased activity of choline acetyltransferase in the medial aspect of the horizontal diagonal band nucleus, the frontal cortex, and CA1 of the dorsal hippocampus. Four other basal forebrain cholinergic nuclei did not show changes in choline acetyltransferase activity after estradiol. These data have implications for possible benefits of estradiol administration to patients with senile dementia of the Alzheimer's type.
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Zou, Shumei; Guo, Junfeng; Gao, Rongbao; Dong, Libo; Zhou, Jianfang; Zhang, Ye; Dong, Jie; Bo, Hong; Qin, Kun; Shu, Yuelong
2013-09-15
In the spring of 2013, a novel avian-origin influenza A (H7N9) virus in Eastern China emerged causing human infections. Concerns that a new influenza pandemic could occur were raised. The potential effect of chemical agents and physical conditions on inactivation of the novel avian influenza H7N9 virus had not been assessed. To determine the inactivation effectiveness of the novel avian influenza A (H7N9) virus under various physical conditions and chemical treatments, two H7N9 viruses A/Anhui/1/2013 and A/Shanghai/1/2013 were treated by varied temperatures, ultraviolet light, varied pHs and different disinfectants. The viruses with 107.7 EID50 were exposed to physical conditions (temperature, ultraviolet light and pH) or treated with commercial chemical agents (Sodium Hypochlorite, Virkon®-S, and Ethanol) respectively. After these treatments, the viruses were inoculated in SPF embryonated chicken eggs, the allantoic fluid was collected after 72-96 hours culture at 35°C and tested by haemagglutination assay. Both of the tested viruses could tolerate conditions under 56°C for 15 minutes or 60°C for 5 minutes, but their infectivity was completely lost under 56°C for 30 minutes, 65°C for 10 minutes, 70°C, 75°C and 100°C for 1 minute. It was also observed that the H7N9 viruses lost their infectivity totally after exposure of ultraviolet light irradiation for 30 minutes or longer time. Additionally, the viruses were completely inactivated at pH less than 2 for 0.5 hour or pH 3 for 24 hours, however, viruses remained infectious under pH treatment of 4-12 for 24 hours. The viruses were totally disinfected when treated with Sodium Hypochlorite, Virkon®-S and Ethanol at recommended concentrations after only 5 minutes. The novel avian influenza A (H7N9) virus can be inactivated under some physical conditions or with chemical treatments, but they present high tolerance to moderately acidic or higher alkali conditions. The results provided the essential information for public health intervention of novel H7N9 avian influenza outbreak.
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Brié, Adrien; Boudaud, Nicolas; Mssihid, Annabelle; Loutreul, Julie; Bertrand, Isabelle; Gantzer, Christophe
2018-04-01
Raspberries are vulnerable products for which industrial treatment solutions ensuring both food safety and sensory quality are not easily applicable. Raspberries have been associated with numerous foodborne outbreaks in recent decades. Ozone has been proven effective as a drinking water treatment against pathogenic microorganisms. Nevertheless, to date, little information is available regarding the effect of gaseous ozone on viruses in food matrices. A comparison of the effect of gaseous ozone on murine norovirus (MNV-1) and hepatitis A virus (HAV) adsorbed on fresh raspberries was performed. Infectious MNV-1 was highly inactivated (>3.3 log 10 ) by ozone (3 ppm, 1 min). The raspberry matrix seems to enhance inactivation by ozone compared to water. The same treatment was observed to have little effect on HAV even for the highest dose under the tested conditions (5 ppm, 3 min). Ozone treatment (5 ppm, 3 min) did not affect the appearance of raspberries even after three days post-treatment. No ozone effect was observed on the genomes detected by RT-PCR on both tested viruses, irrespective of the matrix or tested doses used. Gaseous ozone could therefore be a good candidate for human norovirus inactivation on raspberries but new conditions are needed for it to have significant effects on HAV inactivation. Copyright © 2017 Elsevier Ltd. All rights reserved.
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West, Elizabeth A.; Forcelli, Patrick A.; Murnen, Alice T.; McCue, David L.; Gale, Karen; Malkova, Ludise
2012-01-01
Basolateral amygdala (BLA) function is critical for flexible, goal-directed behavior, including performance on reinforcer devaluation tasks. Here we tested, in rats, the hypothesis that BLA is critical for conditioned reinforcer devaluation during the period when the primary reinforcer (food) is being devalued (by feeding it to satiety), but not thereafter for guiding behavioral choices. We used a spatially-independent task, which employed two visual cues, each predicting one of two foods. An instrumental action (lever press) was required for reinforcer delivery. After training, rats received BLA or sham lesions, or cannulae implanted in BLA. Under control conditions (sham lesions, saline infusions), devaluation of one food significantly decreased responding to the cue associated with that food, when both cues were presented simultaneously during extinction. BLA lesions impaired this devaluation effect. Transient inactivation of BLA by microinfusion of the GABAA agonist muscimol resulted in an impairment, only when BLA was inactivated during satiation. When muscimol was infused after satiation and, therefore, BLA was inactivated only during the choice test, rats showed no impairment. Thus, BLA is necessary for registering or updating cues to reflect updated reinforcer values, but not for guiding choices once the value has been updated. Our results are the first to describe the contribution of rat BLA to specific components of reinforcer devaluation, and are the first to show impairment in reinforcer devaluation following transient inactivation in the rat. PMID:22845705
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Hijnen, W A M; Beerendonk, E F; Medema, G J
2006-01-01
UV disinfection technology is of growing interest in the water industry since it was demonstrated that UV radiation is very effective against (oo)cysts of Cryptosporidium and Giardia, two pathogenic micro-organisms of major importance for the safety of drinking water. Quantitative Microbial Risk Assessment, the new concept for microbial safety of drinking water and wastewater, requires quantitative data of the inactivation or removal of pathogenic micro-organisms by water treatment processes. The objective of this study was to review the literature on UV disinfection and extract quantitative information about the relation between the inactivation of micro-organisms and the applied UV fluence. The quality of the available studies was evaluated and only high-quality studies were incorporated in the analysis of the inactivation kinetics. The results show that UV is effective against all waterborne pathogens. The inactivation of micro-organisms by UV could be described with first-order kinetics using fluence-inactivation data from laboratory studies in collimated beam tests. No inactivation at low fluences (offset) and/or no further increase of inactivation at higher fluences (tailing) was observed for some micro-organisms. Where observed, these were included in the description of the inactivation kinetics, even though the cause of tailing is still a matter of debate. The parameters that were used to describe inactivation are the inactivation rate constant k (cm(2)/mJ), the maximum inactivation demonstrated and (only for bacterial spores and Acanthamoeba) the offset value. These parameters were the basis for the calculation of the microbial inactivation credit (MIC="log-credits") that can be assigned to a certain UV fluence. The most UV-resistant organisms are viruses, specifically Adenoviruses, and bacterial spores. The protozoon Acanthamoeba is also highly UV resistant. Bacteria and (oo)cysts of Cryptosporidium and Giardia are more susceptible with a fluence requirement of <20 mJ/cm(2) for an MIC of 3 log. Several studies have reported an increased UV resistance of environmental bacteria and bacterial spores, compared to lab-grown strains. This means that higher UV fluences are required to obtain the same level of inactivation. Hence, for bacteria and spores, a correction factor of 2 and 4 was included in the MIC calculation, respectively, whereas some wastewater studies suggest that a correction of a factor of 7 is needed under these conditions. For phages and viruses this phenomenon appears to be of little significance and for protozoan (oo)cysts this aspect needs further investigation. Correction of the required fluence for DNA repair is considered unnecessary under the conditions of drinking water practice (no photo-repair, dark repair insignificant, esp. at higher (60 mJ/cm(2)) fluences) and probably also wastewater practice (photo-repair limited by light absorption). To enable accurate assessment of the effective fluence in continuous flow UV systems in water treatment practice, biodosimetry is still essential, although the use of computational fluid dynamics (CFD) improves the description of reactor hydraulics and fluence distribution. For UV systems that are primarily dedicated to inactivate the more sensitive pathogens (Cryptosporidium, Giardia, pathogenic bacteria), additional model organisms are needed to serve as biodosimeter.
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Aldrin-Kirk, Patrick; Davidsson, Marcus; Holmqvist, Staffan; Li, Jia-Yi; Björklund, Tomas
2014-01-01
Synucleinopathies, characterized by intracellular aggregation of α-synuclein protein, share a number of features in pathology and disease progression. However, the vulnerable cell population differs significantly between the disorders, despite being caused by the same protein. While the vulnerability of dopamine cells in the substantia nigra to α-synuclein over-expression, and its link to Parkinson's disease, is well studied, animal models recapitulating the cortical degeneration in dementia with Lewy-bodies (DLB) are much less mature. The aim of this study was to develop a first rat model of widespread progressive synucleinopathy throughout the forebrain using adeno-associated viral (AAV) vector mediated gene delivery. Through bilateral injection of an AAV6 vector expressing human wild-type α-synuclein into the forebrain of neonatal rats, we were able to achieve widespread, robust α-synuclein expression with preferential expression in the frontal cortex. These animals displayed a progressive emergence of hyper-locomotion and dysregulated response to the dopaminergic agonist apomorphine. The animals receiving the α-synuclein vector displayed significant α-synuclein pathology including intra-cellular inclusion bodies, axonal pathology and elevated levels of phosphorylated α-synuclein, accompanied by significant loss of cortical neurons and a progressive reduction in both cortical and striatal ChAT positive interneurons. Furthermore, we found evidence of α-synuclein sequestered by IBA-1 positive microglia, which was coupled with a distinct change in morphology. In areas of most prominent pathology, the total α-synuclein levels were increased to, on average, two-fold, which is similar to the levels observed in patients with SNCA gene triplication, associated with cortical Lewy body pathology. This study provides a novel rat model of progressive cortical synucleinopathy, showing for the first time that cholinergic interneurons are vulnerable to α-synuclein over-expression. This animal model provides a powerful new tool for studies of neuronal degeneration in conditions of widespread cortical α-synuclein pathology, such as DLB, as well an attractive model for the exploration of novel biomarkers.
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Thermal inactivation kinetics of hepatitis A virus in spinach.
Bozkurt, Hayriye; Ye, Xiaofei; Harte, Federico; D'Souza, Doris H; Davidson, P Michael
2015-01-16
Leafy vegetables have been recognized as important vehicles for the transmission of foodborne viral pathogens. To control hepatitis A viral foodborne illness outbreaks associated with mildly heated (e.g., blanched) leafy vegetables such as spinach, generation of adequate thermal processes is important both for consumers and the food industry. Therefore, the objectives of this study were to determine the thermal inactivation behavior of hepatitis A virus (HAV) in spinach, and provide insights on HAV inactivation in spinach for future studies and industrial applications. The D-values calculated from the first-order model (50-72 °C) ranged from 34.40 ± 4.08 to 0.91 ± 0.12 min with a z-value of 13.92 ± 0.87 °C. The calculated activation energy value was 162 ± 11 kJ/mol. Using the information generated in the present study and the thermal parameters of industrial blanching conditions for spinach as a basis (100 °C for 120-180 s), the blanching of spinach in water at 100 °C for 120-180 s under atmospheric conditions will provide greater than 6 log reduction of HAV. The results of this study may be useful to the frozen food industry in designing blanching conditions for spinach to inactivate or control hepatitis A virus outbreaks. Copyright © 2014. Published by Elsevier B.V.
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Inactivation of murine norovirus by chemical biocides on stainless steel
2009-01-01
Background Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces. Methods The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells. Results PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by ≥ 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes). Conclusion Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces. PMID:19583832
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Amir, Shimon; Stewart, Jane
2009-05-15
Key molecular components of the mammalian circadian clock are expressed rhythmically in many brain areas and peripheral tissues in mammals. Here we review findings from our work on rhythms of expression of the clock protein Period2 (PER2) in four regions of the limbic forebrain known to be important in the regulation of motivational and emotional states. These regions include the oval nucleus of the bed nucleus of the stria terminalis (BNSTov), the central nucleus of the amygdala (CEA), the basolateral amygdala (BLA), and the dentate gyrus (DG). Daily rhythms in the expression of PER2 in these regions are controlled by the master circadian pacemaker, the suprachiasmatic nucleus (SCN), but, importantly, they are also sensitive to homeostatic perturbations and to hormonal states that directly influence motivated behavior. Thus, circadian information from the SCN and homeostatic signals are integrated in these regions of the limbic forebrain to affect the temporal organization of motivational and emotional processes.
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NASA Astrophysics Data System (ADS)
Hassanpour, Hossein; Khalaji-Pirbalouty, Valiallah; Nasiri, Leila; Mohebbi, Abdonnaser; Bahadoran, Shahab
2015-11-01
To evaluate oxidant and antioxidant status of the brain (hindbrain, midbrain, and forebrain) in chickens with cold-induced pulmonary hypertension, the measurements of lipid peroxidation, protein oxidation, antioxidant capacity, enzymatic activity, and gene expression (for catalase, glutathione peroxidase, and superoxide dismutases) were done. There were high lipid peroxidation/protein oxidation and low antioxidant capacity in the hindbrain of cold-induced pulmonary hypertensive chickens compared to control ( P < 0.05). In the hypertensive chickens, superoxide dismutase activity was decreased (forebrain, midbrain, and hindbrain), while catalase activity was increased (forebrain and midbrain) ( P < 0.05). Glutathione peroxidase activity did not change. Relative gene expression of catalase and superoxide dismutases (1 and 2) was downregulated, while glutathione peroxidase was upregulated in the brain of the cold-induced pulmonary hypertensive chickens. Probably, these situations in the oxidant and antioxidant status of the brain especially hindbrain may change its function at cardiovascular center and sympathetic nervous system to exacerbate pulmonary hypertension.
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Transcriptional regulation of intermediate progenitor cell generation during hippocampal development
Harris, Lachlan; Zalucki, Oressia; Gobius, Ilan; McDonald, Hannah; Osinki, Jason; Harvey, Tracey J.; Essebier, Alexandra; Vidovic, Diana; Gladwyn-Ng, Ivan; Burne, Thomas H.; Heng, Julian I.; Richards, Linda J.; Gronostajski, Richard M.
2016-01-01
During forebrain development, radial glia generate neurons through the production of intermediate progenitor cells (IPCs). The production of IPCs is a central tenet underlying the generation of the appropriate number of cortical neurons, but the transcriptional logic underpinning this process remains poorly defined. Here, we examined IPC production using mice lacking the transcription factor nuclear factor I/X (Nfix). We show that Nfix deficiency delays IPC production and prolongs the neurogenic window, resulting in an increased number of neurons in the postnatal forebrain. Loss of additional Nfi alleles (Nfib) resulted in a severe delay in IPC generation while, conversely, overexpression of NFIX led to precocious IPC generation. Mechanistically, analyses of microarray and ChIP-seq datasets, coupled with the investigation of spindle orientation during radial glial cell division, revealed that NFIX promotes the generation of IPCs via the transcriptional upregulation of inscuteable (Insc). These data thereby provide novel insights into the mechanisms controlling the timely transition of radial glia into IPCs during forebrain development. PMID:27965439
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Barratt, Kristen S; Arkell, Ruth M
2018-01-01
The ZIC2 transcription factor is one of the most commonly mutated genes in Holoprosencephaly (HPE) probands. HPE is a severe congenital defect of forebrain development which occurs when the cerebral hemispheres fail to separate during the early stages of organogenesis and is typically associated with mispatterning of the embryonic midline. Recent study of genotype-phenotype correlations in HPE cases has defined distinctive features of ZIC2-associated HPE presentation and genetics, revealing that ZIC2 mutation does not produce the craniofacial abnormalities generally thought to characterise HPE but leads to a range of non-forebrain phenotypes. Furthermore, the studies confirm the extent of ZIC2 allelic heterogeneity and that pathogenic variants of ZIC2 are associated with both classic and middle interhemispheric variant (MIHV) HPE which arise from defective ventral and dorsal forebrain patterning, respectively. An allelic series of mouse mutants has helped to delineate the cellular and molecular mechanisms by which one gene leads to defects in these related but distinct embryological processes.
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Baxter, Mark G; Bucci, David J; Gorman, Linda K; Wiley, Ronald G; Gallagher, Michela
2013-10-01
Male Long-Evans rats were given injections of either 192 IgG-saporin, an apparently selective toxin for basal forebrain cholinergic neurons (LES), or vehicle (CON) into either the medial septum and vertical limb of the diagonal band (MS/VDB) or bilaterally into the nucleus basalis magnocellularis and substantia innominata (nBM/SI). Place discrimination in the Morris water maze assessed spatial learning, and a trial-unique matching-to-place task in the water maze assessed memory for place information over varying delays. MS/VDB-LES and nBM/SI-LES rats were not impaired relative to CON rats in acquisition of the place discrimination, but were mildly impaired relative to CON rats in performance of the memory task even at the shortest delay, suggesting a nonmnemonic deficit. These results contrast with effects of less selective lesions, which have been taken to support a role for basal forebrain cholinergic neurons in learning and memory. 2013 APA, all rights reserved
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Kohn, Tamar; Mattle, Michael J; Minella, Marco; Vione, Davide
2016-01-01
Sunlight is known to be a pertinent factor governing the infectivity of waterborne viruses in the environment. Sunlight inactivates viruses via endogenous inactivation (promoted by absorption of solar light in the UVB range by the virus) and exogenous processes (promoted by adsorption of sunlight by external chromophores, which subsequently generate inactivating reactive species). The extent of inactivation is still difficult to predict, as it depends on multiple parameters including virus characteristics, solution composition, season and geographical location. In this work, we adapted a model typically used to estimate the photodegradation of organic pollutants, APEX, to explore the fate of two commonly used surrogates of human viruses (coliphages MS2 and ϕX174) in waste stabilization pond and natural surface water. Based on experimental data obtained in previous work, we modeled virus inactivation as a function of water depth and composition, as well as season and latitude, and we apportioned the contributions of the different inactivation processes to total inactivation. Model results showed that ϕX174 is inactivated more readily than MS2, except at latitudes >60°. ϕX174 inactivation varies greatly with both season (20-fold) and latitude (10-fold between 0 and 60°), and is dominated by endogenous inactivation under all solution conditions considered. In contrast, exogenous processes contribute significantly to MS2 inactivation. Because exogenous inactivation can be promoted by longer wavelengths, which are less affected by changes in season and latitude, MS2 exhibits smaller fluctuations in inactivation throughout the year (10-fold) and across the globe (3-fold between 0 and 60°) compared to ϕX174. While a full model validation is currently not possible due to the lack of sufficient field data, our estimated inactivation rates corresponded well to those reported in field studies. Overall, this study constitutes a step toward estimating microbial water quality as a function of spatio-temporal information and easy-to-determine solution parameters. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Bevilacqua, Antonio; Ciuffreda, Emanuela; Sinigaglia, Milena; Corbo, Maria Rosaria
2015-04-01
This paper reports on the inactivation of spores of 5 strains of Alicyclobacillus acidoterrestris under different stress conditions (acidic and alkaline pH, high temperature, addition of lysozyme, hydrogen peroxide and p-coumaric acid). The research was divided into two different steps; first, each stress was studied alone, thus pointing out a partial uncoupling between spore inactivation and DPA release, as H2O2 reduced spore level below the detection but it did not cause the release of DPA. A partial correlation was found only for acidic and alkaline pH. 2nd step was focused on the combination of pH, temperature and H2O2 through a factorial design; experiments were performed on both fresh and 4 month-old spores and pinpointed a different trend for DPA release as a function of spore age. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Ye, Mu; Huang, Yaoxin; Gurtler, Joshua B; Niemira, Brendan A; Sites, Joseph E; Chen, Haiqiang
2013-05-15
The effects of storage conditions on subsequent high-hydrostatic pressure (HHP) inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters were investigated. Live oysters were inoculated with V. parahaemolyticus or V. vulnificus to ca. 7-8 log MPN/g by feeding and stored at varying conditions (i.e., 21 or 35 °C for 5h, 4 or 10 °C for 1 and 2 days and -18 °C for 2 weeks). Oyster meats were then treated at 225-300 MPa for 2 min at 4, 21 or 35 °C. HHP at 300 MPa for 2 min achieved a >5-log MPN/g reduction of V. parahaemolyticus, completely inactivating V. vulnificus (negative by enrichment) in oysters. Treatment temperatures of 4, 21 and 35 °C did not significantly affect pressure inactivation of V. parahaemolyticus or V. vulnificus (P>0.05). Cold storage at -18, 4 and 10 °C, prior to HHP, decreased V. parahaemolyticus or V. vulnificus populations by 1.5-3.0 log MPN/g, but did not increase their sensitivity to subsequent HHP treatments. The effects of cold storage after HHP on inactivation of V. parahaemolyticus in oysters were also determined. Oysters were inoculated with V. parahaemolyticus and stored at 21 °C for 5h or 4 °C for 1 day. Oyster meats were then treated at 250-300 MPa for 2 min at 21 or 35 °C and stored for 15 days in ice or in a freezer. V. parahaemolyticus populations in HHP-treated oysters gradually decreased during post-HHP ice or frozen storage. A validation study using whole-shell oysters was conducted to determine whether the presence of oyster shells influenced HHP inactivation of V. parahaemolyticus. No appreciable differences in inactivation between shucked oyster meat and whole-shell oysters were observed. HPP at 300 MPa for 2 min at 21 °C, followed by 5-day ice storage or 7-day frozen storage, and HPP at 250 MPa for 2 min at 21 °C, followed by 10-day ice or 7-day frozen storage, completely inactivated V. parahaemolyticus in whole-shell oysters (>7 log reductions). The combination of HHP at a relatively low pressure (e.g., 250 MPa) followed by short-term frozen storage (7 days) could potentially be applied by the shellfish industry as a post-harvest process to eliminate V. parahaemolyticus in oysters. Copyright © 2013 Elsevier B.V. All rights reserved.
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Inactivation of infectious hematopoietic necrosis virus by low levels of iodine
Batts, William N.; Landolt, Marsha L.; Winton, James R.
1991-01-01
The fish rhabdovirus infectious hematopoietic necrosis virus (IHNV) was rapidly inactivated by extremely low concentrations of iodine in water. A 99.9% virus reduction was obtained in 7.5 s when virus (105PFU/ml) and iodine (0.1 mg/liter, final concentration) were combined in distilled-deionized or hatchery water. Iodine efficacy decreased at pHs greater than 7.5 or when proteinaceous material was added to the water. Bovine serum albumin blocked iodine inactivation of the virus more effectively than did equal concentrations of fetal bovine serum or river sediment. Sodium thiosulfate effectively neutralized free iodine. Powder, iodophor, and crystalline iodine solutions inactivated IHNV equally. Iodine rapidly inactivated IHNV isolates representing each of the five electropherotypes. Under the conditions used in this study, inactivation was not affected by temperature, salinity, or water hardness. When Dworshak National Fish Hatchery water was continuously treated to provide a free iodine concentration of 0.14 mg/liter, a 7.5-s exposure to iodine was sufficient to inactivate 99.9% of the IHNV. Iodine added to water that contained IHNV prevented infection of rainbow trout (Oncorhynchus mykiss) fry. These results suggest that the waterborne route of IHNV transmission can be blocked by adding low iodine concentrations to the water supplies of hatcheries.
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High pressure inactivation of Brettanomyces bruxellensis in red wine.
van Wyk, Sanelle; Silva, Filipa V M
2017-05-01
Brettanomyces bruxellensis ("Brett") is a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties. Sulphur dioxide, is currently the preferred method for wine preservation. However, due to its negative effects on consumers, the use of new alternative non-thermal technologies are increasingly being investigated. The aim of this study was to determine and model the effect of high pressure processing (HPP) conditions and yeast strain on the inactivation of "Brett" in Cabernet Sauvignon wine. Processing at 200 MPa for 3 min resulted in 5.8 log reductions. However higher pressure is recommended to achieve high throughput in the wine industry, for example >6.0 log reductions were achieved after 400 MPa for 5 s. The inactivation of B. bruxellensis is pressure and time dependent, with increased treatment time and pressure leading to increased yeast inactivation. It was also found that yeast strain had a significant effect on HPP inactivation, with AWRI 1499 being the most resistant strain. The Weibull model successfully described the HPP "Brett" inactivation. HPP is a viable alternative for the inactivation of B. bruxellensis in wine, with the potential to reduce the industry's reliance on sulphur dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Basal forebrain projections to the lateral habenula modulate aggression reward.
Golden, Sam A; Heshmati, Mitra; Flanigan, Meghan; Christoffel, Daniel J; Guise, Kevin; Pfau, Madeline L; Aleyasin, Hossein; Menard, Caroline; Zhang, Hongxing; Hodes, Georgia E; Bregman, Dana; Khibnik, Lena; Tai, Jonathan; Rebusi, Nicole; Krawitz, Brian; Chaudhury, Dipesh; Walsh, Jessica J; Han, Ming-Hu; Shapiro, Matt L; Russo, Scott J
2016-06-30
Maladaptive aggressive behaviour is associated with a number of neuropsychiatric disorders and is thought to result partly from the inappropriate activation of brain reward systems in response to aggressive or violent social stimuli. Nuclei within the ventromedial hypothalamus, extended amygdala and limbic circuits are known to encode initiation of aggression; however, little is known about the neural mechanisms that directly modulate the motivational component of aggressive behaviour. Here we established a mouse model to measure the valence of aggressive inter-male social interaction with a smaller subordinate intruder as reinforcement for the development of conditioned place preference (CPP). Aggressors develop a CPP, whereas non-aggressors develop a conditioned place aversion to the intruder-paired context. Furthermore, we identify a functional GABAergic projection from the basal forebrain (BF) to the lateral habenula (lHb) that bi-directionally controls the valence of aggressive interactions. Circuit-specific silencing of GABAergic BF-lHb terminals of aggressors with halorhodopsin (NpHR3.0) increases lHb neuronal firing and abolishes CPP to the intruder-paired context. Activation of GABAergic BF-lHb terminals of non-aggressors with channelrhodopsin (ChR2) decreases lHb neuronal firing and promotes CPP to the intruder-paired context. Finally, we show that altering inhibitory transmission at BF-lHb terminals does not control the initiation of aggressive behaviour. These results demonstrate that the BF-lHb circuit has a critical role in regulating the valence of inter-male aggressive behaviour and provide novel mechanistic insight into the neural circuits modulating aggression reward processing.
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Nieuwenhuys, Rudolf
2009-09-10
The forebrain of actinopterygian fishes differs from that of other vertebrates in that it consists of a pair of solid lobes. Lateral ventricles surrounded by nervous tissue are entirely lacking. This peculiar configuration of the actinopterygian forebrain results from an outward bending or eversion of its lateral walls during ontogenesis. Due to this eversion, the telencephalic roof plate is transformed into a wide, membranous structure that surrounds the dorsal and lateral parts of the solid lobes and is attached to their lateral or ventrolateral aspects. Another effect of the eversion is that the ventricular surface of the telencephalic lobes is very extensive, whereas their meningeal surface is small. In many recent publications on the forebrain of actinopterygian fishes, these structures are presented as solid lobes, without any reference to the fact that they are the product of an eversion process, and without any indication concerning the location and extent of their ventricular and meningeal surfaces. It is explained here that, in light of current concepts concerning the histogenesis of the brain, these omissions are intolerable. It is also strongly recommended that the location and extent of these surfaces should always be clearly indicated in brain sections in general, because the simple notion that in the brain of vertebrates the ventricular surface is on the inside and the meningeal surface on the outside has numerous and notable exceptions. Copyright 2009 Wiley-Liss, Inc.
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The cholinergic forebrain arousal system acts directly on the circadian pacemaker
Yamakawa, Glenn R.; Basu, Priyoneel; Cortese, Filomeno; MacDonnell, Johanna; Whalley, Danica; Smith, Victoria M.
2016-01-01
Sleep and wake states are regulated by a variety of mechanisms. One such important system is the circadian clock, which provides temporal structure to sleep and wake. Conversely, changes in behavioral state, such as sleep deprivation (SD) or arousal, can phase shift the circadian clock. Here we demonstrate that the level of wakefulness is critical for this arousal resetting of the circadian clock. Specifically, drowsy animals with significant power in the 7- to 9-Hz band of their EEGs do not exhibit phase shifts in response to a mild SD procedure. We then show that treatments that both produce arousal and reset the phase of circadian clock activate (i.e., induce Fos expression in) the basal forebrain. Many of the activated cells are cholinergic. Using retrograde tract tracing, we demonstrate that cholinergic cells activated by these arousal procedures project to the circadian clock in the suprachiasmatic nuclei (SCN). We then demonstrate that arousal-induced phase shifts are blocked when animals are pretreated with atropine injections to the SCN, demonstrating that cholinergic activity at the SCN is necessary for arousal-induced phase shifting. Finally, we demonstrate that electrical stimulation of the substantia innominata of the basal forebrain phase shifts the circadian clock in a manner similar to that of our arousal procedures and that these shifts are also blocked by infusions of atropine to the SCN. These results establish a functional link between the major forebrain arousal center and the circadian system. PMID:27821764
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Rachman, Ilya M.; Unnerstall, James R.; Pfaff, Donald W.; Cohen, Rochelle S.
1998-01-01
Estrogen has been implicated in brain functions related to affective state, including hormone-related affective disorders in women. Although some reports suggest that estrogen appears to decrease vulnerability to affective disorders in certain cases, the mechanisms involved are unknown. We used the forced swim test (FST), a paradigm used to test the efficacy of antidepressants, and addressed the hypotheses that estrogen alters behavior of ovariectomized rats in the FST and the FST-induced expression of c-fos, a marker for neuronal activity, in the rat forebrain. The behaviors displayed included struggling, swimming, and immobility. One hour after the beginning of the test on day 2, the animals were perfused, and the brains were processed for c-fos immunocytochemistry. On day 1, the estradiol benzoate-treated animals spent significantly less time struggling and virtually no time in immobility and spent most of the time swimming. Control rats spent significantly more time struggling or being immobile during a comparable period. On day 2, similar behavioral patterns with still more pronounced differences were observed between estradiol benzoate and ovariectomized control groups in struggling, immobility, and swimming. Analysis of the mean number of c-fos immunoreactive cell nuclei showed a significant reduction in the estradiol benzoate versus control groups in areas of the forebrain relating to sensory, contextual, and integrative processing. Our results suggest that estrogen-induced neurochemical changes in forebrain neurons may translate into an altered behavioral output in the affective domain. PMID:9811905
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Kuratani, Shigeru; Ahlberg, Per E
2018-01-01
The subdivision of the gnathostome neurocranium into an anterior neural crest-derived moiety and a posterior mesodermal moiety has attracted the interest of researchers for nearly two centuries. We present a synthetic scenario for the evolution of this structure, uniting developmental data from living cyclostomes and gnathostomes with morphological data from fossil stem gnathostomes in a common phylogenetic framework. Ancestrally, vertebrates had an anteroposteriorly short forebrain, and the neurocranium was essentially mesodermal; skeletal structures derived from premandibular ectomesenchyme were mostly anterior to the brain and formed part of the visceral arch skeleton. The evolution of a one-piece neurocranial 'head shield' in jawless stem gnathostomes, such as galeaspids and osteostracans, caused this mesenchyme to become incorporated into the neurocranium, but its position relative to the brain and nasohypophyseal duct remained unchanged. Basically similar distribution of the premandibular ectomesenchyme is inferred, even in placoderms, the earliest jawed vertebrates, in which the separation of hypophyseal and nasal placodes obliterated the nasohypophyseal duct, leading to redeployment of this ectomesenchyme between the separate placodes and permitting differentiation of the crown gnathostome trabecula that floored the forebrain. Initially this region was very short, and the bulk of the premandibular cranial part projected anteroventral to the nasal capsule, as in jawless stem gnathostomes. Due to the lengthening of the forebrain, the anteriorly projecting 'upper lip' was lost, resulting in the modern gnathostome neurocranium with a long forebrain cavity floored by the trabeculae.
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Berger, Michael L
2016-01-01
Membranes prepared from rat brain were treated with increasing concentrations of cationic, neutral, anionic and zwitterionic surfactants. Potent inactivation of [(3)H]MK-801 binding to NMDA receptors (NRs) was provided by the cation cetyl pyridinium (IC50 25 μM) and the neutral digitonin (IC50 37 μM). A 2 h incubation of rat brain membranes at 24°C with 100 μM of the neutral Triton X-100 resulted in about 50% reversible inhibition (without inactivation). Reversible inhibition was also effected by the anion deoxycholate (IC50 700 μM), and by the zwitterions N-lauryl sulfobetaine (12-SB(±), 400 μM) and CHAPS (1.5 mM), with inactivation at higher concentrations. Keeping the NR cation channel in the closed state significantly protected against inactivation by cations and by 12-SB(±), but not by the other detergents. Inactivation depended differentially on the amount of the membranes, on the duration of the treatment, and on the temperature. Varying the amount of membranes by a factor 8 yielded for cetyl trimethylammonium (16-NMe3(+)) IC50s of inactivation from 10 to 80 μM, while for deoxycholate the IC50 of inactivation was 1.2 mM for all tissue quantities. Some compounds inactivated within a few min (16-NMe3(+), digitonin, CHAPS), while inactivation by others took at least half an hour (Triton X-100, deoxycholate, 12-SB(±)). These last 3 ones also exhibited the steepest temperature dependence. Knowledge about the influence of various parameters is helpful in selecting appropriate conditions allowing the treatment of brain membranes with amphiphiles without risking irreversible inactivation. Copyright © 2015 Elsevier B.V. All rights reserved.
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Sosa-Moguel, Odri; Ruiz-Ruiz, Jorge; Martínez-Ayala, Alma; González, Rolando; Drago, Silvina; Betancur-Ancona, David; Chel-Guerrero, Luis
2009-01-01
The influence of lipoxygenase inactivation and extrusion cooking on the physical and nutritional properties of corn/cowpea (Vigna unguiculata) blends was studied. Corn was blended in an 80:15 proportion with cowpea flour treated to inactivate lipoxygenase (CI) or non-inactivated cowpea flour (CNI). Extrusion variables were temperature (150 degrees C, 165 degrees C and 180 degrees C) and moisture (15%, 17% and 19%). Based on their physical properties, the 165 degrees C/15% corn:CNI, and 165 degrees C/15% corn:CI, and 150 degrees C/15% corn:CI blends were chosen for nutritional quality analysis. Extrudate chemical composition indicated high crude protein levels compared with standard corn-based products. With the exception of lysine, essential amino acids content in the three treatments met FAO requirements. Extrusion and lipoxygenase inactivation are promising options for developing corn/cowpea extruded snack products with good physical properties and nutritional quality.
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Inactivation of Bacillus atrophaeus by OH radicals
NASA Astrophysics Data System (ADS)
Ono, Ryo; Yonetamari, Kenta; Tokumitsu, Yusuke; Yonemori, Seiya; Yasuda, Hachiro; Mizuno, Akira
2016-08-01
The inactivation of Bacillus atrophaeus by OH radicals is measured. This study aims to evaluate the bactericidal effects of OH radicals produced by atmospheric-pressure nonthermal plasma widely used for plasma medicine; however, in this study, OH radicals are produced by vacuum ultraviolet (VUV) photolysis of water vapor instead of plasma to allow the production of OH radicals with almost no other reactive species. A 172 nm VUV light from a Xe2 excimer lamp irradiates a He-H2O mixture flowing in a quartz tube to photodissociate H2O to produce OH, H, O, HO2, H2O2, and O3. The produced reactive oxygen species (ROS) flow out of the quartz tube nozzle to the bacteria on an agar plate and cause inactivation. The inactivation by OH radicals among the six ROS is observed by properly setting the experimental conditions with the help of simulations calculating the ROS densities. A 30 s treatment with approximately 0.1 ppm OH radicals causes visible inactivation.
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Bactericidal Effect of Zero-Valent Iron Nanoparticles on Escherichia coli
Lee, Changha; Kim, Jee Yeon; Lee, Won Il; Nelson, Kara L.; Yoon, Jeyong; Sedlak, David L.
2008-01-01
Zero-valent iron nanoparticles (nano-Fe0) in aqueous solution rapidly inactivated Escherichia coli (E. coli). A strong bactericidal effect of nano-Fe0 was found under deaerated conditions, with a linear correlation between log inactivation and nano-Fe0 dose (0.82 log inactivation / mg/L nano-Fe0 · hr). The inactivation of E. coli under air saturation required much higher nano-Fe0 doses due to the corrosion and surface oxidation of nano-Fe0 by dissolved oxygen. Significant physical disruption of the cell membranes was observed in E. coli exposed to nano-Fe0, which may have caused the inactivation, or enhanced the biocidal effects of dissolved iron. The reaction of Fe(II) with intracellular oxygen or hydrogen peroxide also may have induced oxidative stress by producing reactive oxygen species. The bactericidal effect of nano-Fe0 was a unique property of nano-Fe0, which was not observed in other types of iron-based compounds. PMID:18678028
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Inactivation of human and simian rotaviruses by chlorine dioxide
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chen, Yu-Shiaw; Vaughn, J.M.
1990-05-01
The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4{degree}C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10{sup 5}-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate a neutral pH, and the sensitivities to chlorine dioxide weremore » similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants.« less
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Lee, Y M; Benisek, W F
1976-03-25
Rabbit muscle phosphorylase b reacts with the phosphate-like reagent potassium ferrate, K2FeO4, a potent oxidizing agent. The reaction results in inactivation of the enzyme and abolition of the ability of the enzyme to bind 5'-AMP. Activating and nonactivating nucleotides which bind at the 5'-AMP binding site such as 5'-AMP, 2'-AMP, 3'-AMP, and 5'-IMP substantially protect the enzyme from inactivation by ferrate. One to two residues of tyrosine and approximately 1 residue of cysteine are modified by ferrate under the conditions employed. Tyrosine is protected by 5-AMP, whereas cysteine is not. The tyrosine modification is suggested as the inactivating chemical reaction. The location of the inactivating reaction is suggested to be in or near the 5'-AMP binding site. The structural and chemical properties of ferrate ion are discussed and compared to those of phosphate. Ferrate ion may be a reagent useful for phosphate group binding site-directed modification of proteins.
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Disinfecting capabilities of oxychlorine compounds.
Noss, C I; Olivieri, V P
1985-01-01
The bacterial virus f2 was inactivated by chlorine dioxide at acidic, neutral, and alkaline pH values. The rate of inactivation increased with increasing pH. Chlorine dioxide disproportionation products, chlorite and chlorate, were not active disinfectants. As chlorine dioxide solutions were degraded under alkaline conditions, they displayed reduced viricidal effectiveness, thereby confirming the chlorine dioxide free radical as the active disinfecting species. PMID:3911893
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ERIC Educational Resources Information Center
Lee, Inah; Shin, Ji Yun
2012-01-01
The exact roles of the medial prefrontal cortex (mPFC) in conditional choice behavior are unknown and a visual contextual response selection task was used for examining the issue. Inactivation of the mPFC severely disrupted performance in the task. mPFC inactivations, however, did not disrupt the capability of perceptual discrimination for visual…
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Jentsch, J D; Roth, R H; Taylor, J R
2000-01-01
We have discussed the role of dopamine in modulating the interactions between cortical and striatal regions that are involved in behavioral regulation. The evidence reviewed seems to suggest that dopamine acts, overall, to promote stimulus-induced responding for conditioned or reward-related stimuli by integrative actions at multiple forebrain sites. It is thus not surprising that dopaminergic dysfunction has been implicated in a number of neuropsychiatric disorders that involve abnormal cognitive and affective function. Future studies aimed at pinpointing the precise anatomical sites of action and molecular mechanisms involved in dopaminergic transmission within the corticolimbic circuit are critical for trying to disentangle the cellular mechanisms by which dopamine exerts its actions. Moreover, the afferent control of dopamine neurons from brainstem and forebrain sites need to be fully explored in order to begin to understand what mechanisms are involved in regulating the dopaminergic response to stimuli with incentive value. Finally, the post-synaptic consequences of prolonged and supranormal dopaminergic activation need to be investigated in order to understand what persistent neuroadaptations result from chronic activation of this neuromodulatory system (e.g. in drug addiction). Answers to these sorts of questions will undoubtedly provide important insights into the nature of dopaminergic function in the animal and human brain.
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Nichols, Matthew; Elustondo, Pia A; Warford, Jordan; Thirumaran, Aruloli; Pavlov, Evgeny V; Robertson, George S
2017-08-01
The effects of global mitochondrial calcium (Ca 2+ ) uniporter (MCU) deficiency on hypoxic-ischemic (HI) brain injury, neuronal Ca 2+ handling, bioenergetics and hypoxic preconditioning (HPC) were examined. Forebrain mitochondria isolated from global MCU nulls displayed markedly reduced Ca 2+ uptake and Ca 2+ -induced opening of the membrane permeability transition pore. Despite evidence that these effects should be neuroprotective, global MCU nulls and wild-type (WT) mice suffered comparable HI brain damage. Energetic stress enhanced glycolysis and depressed Complex I activity in global MCU null, relative to WT, cortical neurons. HI reduced forebrain NADH levels more in global MCU nulls than WT mice suggesting that increased glycolytic consumption of NADH suppressed Complex I activity. Compared to WT neurons, pyruvate dehydrogenase (PDH) was hyper-phosphorylated in MCU nulls at several sites that lower the supply of substrates for the tricarboxylic acid cycle. Elevation of cytosolic Ca 2+ with glutamate or ionomycin decreased PDH phosphorylation in MCU null neurons suggesting the use of alternative mitochondrial Ca 2+ transport. Under basal conditions, global MCU nulls showed similar increases of Ca 2+ handling genes in the hippocampus as WT mice subjected to HPC. We propose that long-term adaptations, common to HPC, in global MCU nulls compromise resistance to HI brain injury and disrupt HPC.
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The Role of the Central Noradrenergic System in Behavioral Inhibition
Stone, Eric A.; Lin, Yan; Sarfraz, Yasmeen; Quartermain, David
2011-01-01
Although the central noradrenergic system has been shown to be involved in a number of behavioral and neurophysiological processes, the relation of these to its role in depressive illness has been difficult to define. The present review discusses the hypothesis that one of its chief functions that may be related to affective illness is the inhibition of behavioral activation, a prominent symptom of the disorder. This hypothesis is found to be consistent with most previous neuropsychopharmacological and immunohistochemical experiments on active behavior in rodents in a variety of experimental conditions using manipulation of neurotransmission at both locus coeruleus and forebrain adrenergic receptors. The findings support a mechanism in which high rates of noradrenergic neural activity suppress the neural activity of principal neurons in forebrain regions mediating active behavior. The suppression may be mediated through postsynaptic galaninergic and adrenergic receptors, and via the release of corticotrophin-releasing hormone. The hypothesis is consistent with clinical evidence for central noradrenergic system hyperactivity in depressives and with the view that this hyperactivity is a contributing etiological factor in the disorder. A similar mechanism may underlie the ability of the noradrenergic system to suppress seizure activity suggesting that inhibition of the spread of neural activation may be a unifying function. PMID:21315760
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Zhu, Shanshan; Cordner, Zachary A; Xiong, Jiali; Chiu, Chi-Tso; Artola, Arabiye; Zuo, Yanning; Nelson, Andrew D; Kim, Tae-Yeon; Zaika, Natalya; Woolums, Brian M; Hess, Evan J; Wang, Xiaofang; Chuang, De-Maw; Pletnikov, Mikhail M; Jenkins, Paul M; Tamashiro, Kellie L; Ross, Christopher A
2017-09-26
Genome-wide association studies have implicated the ANK3 locus in bipolar disorder, a major human psychotic illness. ANK3 encodes ankyrin-G, which organizes the neuronal axon initial segment (AIS). We generated a mouse model with conditional disruption of ANK3 in pyramidal neurons of the adult forebrain (Ank-G cKO). This resulted in the expected loss of pyramidal neuron AIS voltage-gated sodium and potassium channels. There was also dramatic loss of markers of afferent GABAergic cartridge synapses, resembling the cortical microcircuitry changes in brains from psychotic patients, and suggesting disinhibition. Expression of c-fos was increased in cortical pyramidal neurons, consistent with increased neuronal activity due to disinhibition. The mice showed robust behavioral phenotypes reminiscent of aspects of human mania, ameliorated by antimania drugs lithium and valproate. Repeated social defeat stress resulted in repeated episodes of dramatic behavioral changes from hyperactivity to "depression-like" behavior, suggestive of some aspects of human bipolar disorder. Overall, we suggest that this Ank-G cKO mouse model recapitulates some of the core features of human bipolar disorder and indicates that cortical microcircuitry alterations during adulthood may be involved in pathogenesis. The model may be useful for studying disease pathophysiology and for developing experimental therapeutics.
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Thermal inactivation of poliovirus type 1 in water, milk and yoghurt.
Strazynski, Marco; Krämer, Johannes; Becker, Barbara
2002-03-25
Loss of infectivity of poliovirus type 1, strain Sabin, during heating, freezing, and storage in water, milk and yoghurt was determined by plaque-titration in Vero cell cultures. The heating experiments simulated the conditions arising during the processing of milk and yoghurt, for example high-temperature heating (95 degrees C, 15 and 30 s), short-time pasteurization (72 degrees C, 15 and 30 s), long-time pasteurization (62 degrees C, 30 min), and yoghurt-fermentation (42 degrees C, 30 min and 180 min). Only high-temperature heating, long-time pasteurization and short-time pasteurization for 30 s proved to be reliable methods of inactivating polioviruses present in water, milk and yoghurt completely. Short-time pasteurization for 15 s and the conditions of yoghurt-fermentation failed to cause complete inactivation of polioviruses. Additionally, polioviruses mixed in milk or yoghurt withstood these procedures with significantly lower reductions of infectivity than in water. Heating at 55 degrees C for 30 min resulted in complete inactivation of polioviruses, regardless of the suspending medium. The infectivity of polioviruses is scarcely affected by freezing (-20 degrees C, 30 min) and storage (24 days) at low temperatures (4 degrees C) and high humidity (a(w) = 0.99).
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Aschenbrenner, Mathias; Kulozik, Ulrich; Foerst, Petra
2012-12-01
The aim of this work was to describe the temperature dependence of microbial inactivation for several storage conditions and protective systems (lactose, trehalose and dextran) in relation to the physical state of the sample, i.e. the glassy or non-glassy state. The resulting inactivation rates k were described by applying two models, Arrhenius and Williams-Landel-Ferry (WLF), in order to evaluate the relevance of diffusional limitation as a protective mechanism. The application of the Arrhenius model revealed a significant decrease in activation energy E(a) for storage conditions close to T(g). This finding is an indication that the protective effect of a surrounding glassy matrix can, at least, partly be ascribed to its inherent restricted diffusion and mobility. The application of the WLF model revealed that the temperature dependence of microbial inactivation above T(g) is significantly weaker than predicted by the universal coefficients. Thus, it can be concluded that microbial inactivation is not directly linked with the mechanical relaxation behavior of the surrounding matrix as it was reported for viscosity and crystallization phenomena in case of disaccharide systems. Copyright © 2012. Published by Elsevier Inc.
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Brette, Fabien; Lacampagne, Alain; Sallé, Laurent; Findlay, Ian; Le Guennec, Jean-Yves
2003-08-01
Inactivation of the L-type Ca2+ current (ICaL) was studied in isolated guinea pig ventricular myocytes with different ionic solutions. Under basal conditions, ICaL of 82% of cells infused with Cs+-based intracellular solutions showed enhanced amplitude with multiphasic decay and diastolic depolarization-induced facilitation. The characteristics of ICaL in this population of cells were not due to contamination by other currents or an artifact. These phenomena were reduced by ryanodine, caffeine, cyclopiazonic acid, the protein kinase A inhibitor H-89, and the cAMP-dependent protein kinase inhibitor. Forskolin and isoproterenol increased ICaL by only approximately 60% in these cells. Cells infused with either N-methyl-d-glucamine or K+-based intracellular solutions did not show multiphasic decay or facilitation under basal conditions. Isoproterenol increased ICaL by approximately 200% in these cells. In conclusion, we show that multiphasic inactivation of ICaL is due to Ca2+-dependent inactivation that is reversible on a time scale of tens of milliseconds. Cs+ seems to activate the cAMP-dependent protein kinase pathway when used as a substitute for K+ in the pipette solution.
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Chueca, Beatriz; Pagán, Rafael; García-Gonzalo, Diego
2014-10-17
Oxygenated monoterpenes citral and carvacrol are common constituents of many essential oils (EOs) that have been extensively studied as antimicrobial agents but whose mechanisms of microbial inactivation have not been totally elucidated. A recent study described a mechanism of Escherichia coli death for (+)-limonene, a hydrocarbon monoterpene also frequently present in EOs, similar to the common mechanism proposed for bactericidal antibiotics. This mechanism involves the formation of Fenton-mediated hydroxyl radical, a reactive oxygen species (ROS), via tricarboxylic acid (TCA) cycle, which would ultimately inactivate cells. Our objective was to determine whether E. coli MG1655 inactivation by citral and carvacrol follows a similar mechanism of cell death. Challenging experiments with 300μL/L citral and 100μL/L carvacrol inactivated at least 2.5log10cycles of exponentially growing cells in 3h under aerobic conditions. The presence of thiourea (an ROS scavenger) reduced cell inactivation in 2log10cycles, demonstrating the role of ROS in cell death. Decreased resistance of a ΔrecA mutant (deficient in an enzyme involved in SOS response to DNA damage) indicated that citral and carvacrol caused oxidative damage to DNA. Although the mechanism of E. coli inactivation by carvacrol and citral was similarly mediated by ROS, their formation did not follow the same pathways described for (+)-limonene and bactericidal drugs because neither Fenton reaction nor NADH production via the TCA cycle was involved in cell death. Moreover, further experiments demonstrated antimicrobial activity of citral and carvacrol in anaerobic environments without the involvement of ROS. As a consequence, cell death by carvacrol and citral in anaerobiosis follows a different mechanism than that observed under aerobic conditions. These results demonstrated a different mechanism of inactivation by citral and carvacrol with regard to (+)-limonene and bactericidal antibiotics, indicating the complexity of the mechanisms of bacterial inactivation among EO constituents. Advancements in the description of these mechanisms will help in extending and improving the use of these compounds as natural antimicrobials. Copyright © 2014 Elsevier B.V. All rights reserved.
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Ammonia Inactivation of Ascaris Ova in Ecological Compost by Using Urine and Ash
Parzen, Rebecca E.; Mercado Guzmán, Álvaro
2012-01-01
Viable ova of Ascaris lumbricoides, an indicator organism for pathogens, are frequently found in feces-derived compost produced from ecological toilets, demonstrating that threshold levels of time, temperature, pH, and moisture content for pathogen inactivation are not routinely met. Previous studies have determined that NH3 has ovicidal properties for pathogens, including Ascaris ova. This research attempted to achieve Ascaris inactivation via NH3 under environmental conditions commonly found in ecological toilets and using materials universally available in an ecological sanitation setting, including compost (feces and sawdust), urine, and ash. Compost mixed with stored urine and ash produced the most rapid inactivation, with significant inactivation observed after 2 weeks and with a time to 99% ovum inactivation (T99) of 8 weeks. Compost mixed with fresh urine and ash achieved a T99 of 15 weeks, after a 4-week lag phase. Both matrices had relatively high total-ammonia concentrations and pH values of >9.24 (pKa of ammonia). In compost mixed with ash only, and in compost mixed with fresh urine only, inactivation was observed after an 11-week lag phase. These matrices contained NH3 concentrations of 164 to 173 and 102 to 277 mg/liter, respectively, when inactivation occurred, which was below the previously hypothesized threshold for inactivation (280 mg/liter), suggesting that a lower threshold NH3 concentration may be possible with a longer contact time. Other significant results include the hydrolysis of urea to ammonia between pH values of 10.4 and 11.6, above the literature threshold pH of 10. PMID:22582051
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Ammonia inactivation of Ascaris ova in ecological compost by using urine and ash.
McKinley, James W; Parzen, Rebecca E; Mercado Guzmán, Álvaro
2012-08-01
Viable ova of Ascaris lumbricoides, an indicator organism for pathogens, are frequently found in feces-derived compost produced from ecological toilets, demonstrating that threshold levels of time, temperature, pH, and moisture content for pathogen inactivation are not routinely met. Previous studies have determined that NH(3) has ovicidal properties for pathogens, including Ascaris ova. This research attempted to achieve Ascaris inactivation via NH(3) under environmental conditions commonly found in ecological toilets and using materials universally available in an ecological sanitation setting, including compost (feces and sawdust), urine, and ash. Compost mixed with stored urine and ash produced the most rapid inactivation, with significant inactivation observed after 2 weeks and with a time to 99% ovum inactivation (T(99)) of 8 weeks. Compost mixed with fresh urine and ash achieved a T(99) of 15 weeks, after a 4-week lag phase. Both matrices had relatively high total-ammonia concentrations and pH values of >9.24 (pK(a) of ammonia). In compost mixed with ash only, and in compost mixed with fresh urine only, inactivation was observed after an 11-week lag phase. These matrices contained NH(3) concentrations of 164 to 173 and 102 to 277 mg/liter, respectively, when inactivation occurred, which was below the previously hypothesized threshold for inactivation (280 mg/liter), suggesting that a lower threshold NH(3) concentration may be possible with a longer contact time. Other significant results include the hydrolysis of urea to ammonia between pH values of 10.4 and 11.6, above the literature threshold pH of 10.
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Factors influencing inactivation of Klebsiella pneumoniae by chlorine and chloramine.
Goel, Sudha; Bouwer, Edward J
2004-01-01
Inactivation of Klebsiella pneumoniae cultures by chlorine and chloramine was evaluated under different growth conditions by varying nutrient media dilution, concentrations of essential inorganic nutrients (FeCl3, MgSO4, phosphate, and ammonium salts), and temperature. All inactivation assays were performed at room temperature (22-23 degrees C) and near neutral pH (7.2-7.5). C*T(99.9) values for chlorine increased >20-fold and for chloramine increased 2.6-fold when cells were grown in 100-fold diluted nutrient broth (2NB) solutions (final TOC of 35-40 mg/L). Background levels of Mg: 6.75 x 10(-2) mM and Fe: 3.58 x 10(-5) mM or high levels of FeCl3 (0.01 mM) and MgSO4 (1 mM) during growth resulted in the highest resistances to chlorine with C*T(99.9) values of 13.06 (+/-0.91) and 13.78 (+/-1.97) mg-min/L, respectively. Addition of low levels of FeCl3 (0.001 mM) and MgSO4 (0.1 mM) to K. pneumoniae cultures during growth resulted in the lowest bacterial resistances to inactivation; C*T(99.9) values ranged from 0.28 (+/-0.06) to 1.88 (+/-0.53)mg-min/L in these cultures. Increase in growth temperature from 22.5 degrees C to 35 degrees C for unamended 2NB cultures resulted in a 42-fold decrease in C*T(99.9) values for chlorine. A similar change in temperature resulted in no significant change in C*T(99.9) values for chloramine. These results indicate that inactivation of K. pneumoniae cultures by chlorine was highly sensitive to changes in growth conditions unlike inactivation by chloramine.
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Studies on the inactivation of human parvovirus 4.
Baylis, Sally A; Tuke, Philip W; Miyagawa, Eiji; Blümel, Johannes
2013-10-01
Human parvovirus 4 (PARV4) is a novel parvovirus, which like parvovirus B19 (B19V) can be a contaminant of plasma pools used to prepare plasma-derived medicinal products. Inactivation studies of B19V have shown that it is more sensitive to virus inactivation strategies than animal parvoviruses. However, inactivation of PARV4 has not yet been specifically addressed. Treatment of parvoviruses by heat or low-pH conditions causes externalization of the virus genome. Using nuclease treatment combined with real-time polymerase chain reaction, the extent of virus DNA externalization was used as an indirect measure of the inactivation of PARV4, B19V, and minute virus of mice (MVM) by pasteurization of albumin and by low-pH treatment. Infectivity studies were performed in parallel for B19V and MVM. PARV4 showed greater resistance to pasteurization and low-pH treatment than B19V, although PARV4 was not as resistant as MVM. There was a 2- to 3-log reduction of encapsidated PARV4 DNA after pasteurization and low-pH treatment. In contrast, B19V was effectively inactivated while MVM was stable under these conditions. Divalent cations were found to have a stabilizing effect on PARV4 capsids. In the absence of divalent cations, even at neutral pH, there was a reduction of PARV4 titer, an effect not observed for B19V or MVM. In the case of heat treatment and incubation at low pH, PARV4 shows intermediate resistance when compared to B19V and MVM. Divalent cations seem important for stabilizing PARV4 virus particles. © 2013 American Association of Blood Banks.
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Xia, Dehua; Li, Yan; Huang, Guocheng; Yin, Ran; An, Taicheng; Li, Guiying; Zhao, Huijun; Lu, Anhuai; Wong, Po Keung
2017-04-01
This study introduces natural occurring magnetic pyrrhotite (NP) as an environmentally friendly, easy available, and cost-effective alternative catalyst to activate persulfate (PS) of controlling microbial water contaminants. The E. coli K-12 inactivation kinetics observed in batch experiments was well described with first-order reaction. The optimum inactivation rate (k = 0.47 log/min) attained at a NP dose of 1 g/L and a PS dose of 1 mM, corresponding to total inactivation of 7 log 10 cfu/mL cells within 15 min. Measured k increased > 2-fold when temperature increased from 20 to 50 °C; and > 4-fold when pH decreased from 9 to 3. Aerobic conditions were more beneficial to cell inactivation than anaerobic conditions due to more reactive oxygen species (ROS) generated. ROS responsible for the inactivation were identified to be SO 4 - > OH > H 2 O 2 based on a positive scavenging test and in situ ROS determination. In situ characterization suggested that PS effectively bind to NP surface was likely to form charge transfer complex (≡Fe(II)⋯O 3 SOOSO 3 - ), which mediated ROS generation and E. coli K-12 oxidation. The increased cell-envelope lesions consequently aggravated intracellular protein depletion and genome damage to cause definite bacterial death. The NP still maintained good physiochemical structure and stable activity even after 4 cycle. Moreover, NP/PS system also exhibited good E. coli K-12 inactivation efficiency in authentic water matrices like surface water and effluents of secondary wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Zhai, Yali; Kuick, Rork; Tipton, Courtney; Wu, Rong; Sessine, Michael; Wang, Zhong; Baker, Suzanne J.; Fearon, Eric R.; Cho, Kathleen R.
2015-01-01
Inactivation of the ARID1A tumor suppressor gene is frequent in ovarian endometrioid (OEC) and clear cell carcinomas (OCCC), often in conjunction with mutations activating the PI3K/AKT and/or canonical Wnt signaling pathways. Prior work has shown that conditional bi-allelic inactivation of the Apc and Pten tumor suppressor genes in the mouse ovarian surface epithelium (OSE) promotes outgrowth of tumors that reflect the biological behavior and gene expression profiles of human OECs harboring comparable Wnt and PI3K/AKT pathway defects, though the mouse tumors are more poorly differentiated than their human tumor counterparts. We found that conditional inactivation of one or both Arid1a alleles in OSE concurrently with Apc and Pten inactivation unexpectedly prolonged survival of tumor-bearing mice and promoted striking epithelial differentiation of the cancer cells, resulting in morphological features akin to those in human OECs. Enhanced epithelial differentiation was linked to reduced expression of mesenchymal markers N-cadherin and vimentin, and increased expression of epithelial markers Crb3 and E-cadherin. Global gene expression profiling showed enrichment for genes associated with mesenchymal-to-epithelial transition in the Arid1a-deficient tumors. We also found that an activating (E545K) Pik3ca mutation, unlike Pten inactivation or Pik3ca H1047R mutation, cannot cooperate with Arid1a loss to promote ovarian cancer development in the mouse. Our results indicate the Arid1a tumor suppressor gene has a key role in regulating OEC differentiation, and paradoxically the mouse cancers with more initiating tumor suppressor gene defects had a less aggressive phenotype than cancers arising from fewer gene alterations. PMID:26279473
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Faber-Barata, Joana; Sola-Penna, Mauro
2005-01-01
Trehalose and glycerol are known as good stabilizers of function and structure of several macromolecules against stress conditions. We previously reported that they have comparable effectiveness on protecting two yeast cytosolic enzymes against thermal inactivation. However, enzyme protection has always been associated to a decrease in catalytic activity at the stabilizing conditions i.e., the presence of the protective molecule. In the present study we tested trehalose and glycerol on thermal protection of the mammalian cytosolic enzyme phosphofructokinase. Here we found that trehalose was able to protect phosphofructokinase against thermal inactivation as well as to promote an activation of its catalytic activity. The enzyme incubated in the presence of 1 M trehalose did not present any significant inactivation within 2 h of incubation at 50 degrees C, contrasting to control experiments where the enzyme was fully inactivated during the same period exhibiting a t0.5 for thermal inactivation of 56+/-5 min. On the other hand, enzyme incubated in the presence of 37.5% (v/v) glycerol was not protected against incubation at 50 degrees C. Indeed, when phosphofructokinase was incubated for 45 min at 50 degrees C in the presence of lower concentrations of glycerol (7.5-25%, v/v), the remaining activity was 2-4 times lower than control. These data show that the compatibility of effects previously shown for trehalose and glycerol with some yeast cytosolic enzymes can not be extended to all globular enzyme system. In the case of phosphofructokinase, we believe that its property of shifting between several different complex oligomers configurations can be influenced by the physicochemical properties of the stabilizing molecules.
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GLT-1: The elusive presynaptic glutamate transporter
Rimmele, Theresa S.; Rosenberg, Paul A.
2016-01-01
Historically, glutamate uptake in the CNS was mainly attributed to glial cells for three reasons: 1) none of the glutamate transporters were found to be located in presynaptic terminals of excitatory synapses; 2) the putative glial transporters, GLT-1 and GLAST are expressed at high levels in astrocytes; 3) studies of the constitutive GLT-1 knockout as well as pharmacological studies demonstrated that >90% of glutamate uptake into forebrain synaptosomes is mediated by the operation of GLT-1. Here we summarize the history leading up to the recognition of GLT-1a as a presynaptic glutamate transporter. A major issue now is understanding the physiological and pathophysiologial significance of the expression of GLT-1 in presynaptic terminals. To elucidate the cell-type specific functions of GLT-1, a conditional knockout was generated with which to inactivate the GLT-1 gene in different cell types using Cre/lox technology. Astrocytic knockout led to an 80% reduction of GLT-1 expression, resulting in intractable seizures and early mortality as seen also in the constitutive knockout. Neuronal knockout was associated with no obvious phenotype. Surprisingly, synaptosomal uptake capacity (Vmax) was found to be significantly reduced, by 40%, in the neuronal knockout, indicating that the contribution of neuronal GLT-1 to synaptosomal uptake is disproportionate to its protein expression (5–10%). Conversely, the contribution of astrocytic GLT-1 to synaptosomal uptake was much lower than expected. In contrast, the loss of uptake into liposomes prepared from brain protein from astrocyte and neuronal knockouts was proportionate with the loss of GLT-1 protein, suggesting that a large portion of GLT-1 in astrocytic membranes in synaptosomal preparations is not functional, possibly because of a failure to reseal. These results suggest the need to reinterpret many previous studies using synaptosomal uptake to investigate glutamate transport itself as well as changes in glutamate homeostasis associated with normal functions, neurodegeneration, and response to drugs. PMID:27129805
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Hatano, Hiroshi; Sakamoto, Masako; Hayashi, Kazuo; Kamiya, Seigo
2015-08-01
Temperature, concentration and time are the three factors that affect the inactivation capacity of iodine antiseptics. We investigated the effect of these factors on the microbe inactivation of Iodine-Polyvinyl Alcohol ophthalmic and eye washing solution (PA * IODO), and also investigated the preservation conditions on stability of the inactivation activity of the PA * IODO. Test microbes were mixed with PA * IODO, varying the three factors. The live microbes were counted after each reaction. The effects of plugging and preservation temperature were investigated to determine the preserving stability. The inactivation capacity of PA * IODO tended to decrease in almost all microbes tested at 4 degrees C. Twenty times or less diluted PA * IODO killed almost all microbes completely. The time effect was more marked in viruses. Plugging and low-temperature made iodine concentration in diluted PA * IODO remain relatively high. The concentration of PA * IODO affected the inactivation ability more than the temperature and time, although all the three factors correlated positively to the inactivation. For preservation the diluted PA * IODO needed plugging and low temperature.
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Wang, G K
1984-01-01
The effects of externally applied chloramine-T on the excitability of single toad myelinated nerve fibres were studied. Chloramine-T is a mild oxidant which reacts specifically with the cysteine and methionine residues of proteins. Chloramine-T prolongs the action potential of a single myelinated fibre by more than 1000-fold. This effect is concentration- and time-dependent; higher concentrations and longer incubation times increase prolongation. Under voltage-clamp conditions, sodium channel inactivation is markedly inhibited by chloramine-T while sodium channel activation remains normal. Prolonged depolarization of the membrane leads to a maintained sodium current. The maintained sodium currents show activation kinetics, dependence on membrane potential, and reversal potentials which are similar to those of normal, inactivating sodium currents in untreated fibres. Both the maintained and the peak sodium currents are equally inhibited by tetrodotoxin. After partial removal of sodium inactivation by brief exposures to chloramine-T, the voltage dependence of the steady-state sodium current inactivation (h infinity) is shifted in the depolarized direction by about 20 mV, even after correction for the non-inactivating component contributed by the maintained current. The phenomena described here imply that cysteine or methionine residues are critical for the sodium channel inactivation processes. The two different modifications of inactivation, its removal shown by the maintained current, and the shift in the voltage-dependence of the remaining inactivatable channels, reveal that at least two separate residues are modified by chloramine-T. PMID:6321714
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, W.B.
..beta..-Hydroxydecanoyl thioester dehydrase catalyzes the interconversion of thioesters of (R)-3-hydroxydecanoic acid, (E)-2-decenoic acid, and (Z)-3-decenoic acid. Dehydrase is irreversibly inactivated by the N-acetylcysteamine thioester of 3-decynoic acid (3-decynoyl-NAC). This is the classic example of suicide enzyme inactivation. The structure of the dehydrase-inactivator adduct is still unclear. The purpose of this thesis is to determine the structure of the inactivator moiety and the stoichiometry of the inactivation of this dimeric enzyme, as well as to conduct structural studies on dehydrase itself. 3-(2-/sup 13/C)Decynoyl-NAC was synthesized and incubated with homogeneous dehydrase. The spectra showed that dehydrase adds to the inactivator so asmore » to quickly produce an (E)-3-(N/sup im/-histidinyl)-3-decenoyl thioester adduct at the active site. This species is slowly converted to the 2-decenoyl thioester congener. Titration of dehydrase with 3-(2/sup 13/C)decynoyl-NAC under these conditions clearly indicated that 2 moles of inactivator are bound to each mole of dehydrase dimer. These experiments provide a self-consistent picture of dehydrase inactivation by 3-decynoyl-NAC and normal dehydrase-catalyzed reactions. Dehydrase was cleaved by chemical fragmentation, and the resulting mixture of peptides were separated by reversed-phase HPLC. Partial N-terminal sequences of purified peptides were obtained by automated Edman technology« less
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Lee, Mun-Yong; Choi, Yun-Sik; Choi, Jeong-Sun; Min, Do Sik; Chun, Myung-Hoon; Kim, Ok Nyu; Lee, Sang Bok; Kim, Seong Yun
2002-01-11
The cellular localization and spatiotemporal expression pattern of APG-2 protein, a member of the heat shock protein 110 family, were investigated in the rat hippocampus after transient forebrain ischemia. The spatiotemporal patterns of immunoreactivity of both APG-2 and glial fibrillary acidic protein were very similar, indicating that reactive astrocytes express APG-2, which was confirmed by double immunofluorescence histochemistry. Colocalization of APG-2 and a neuronal marker NeuN in the neurons of the CA2 and CA3 subfields was also confirmed.
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The ontogenesis of the forebrain commissures and the determination of brain asymmetries.
Lent, R; Schmidt, S L
1993-02-01
We have reviewed the organization and development of the interhemispheric projections through the forebrain commissures, especially those of the CC, in connection with the development of brain asymmetries. Analyzing the available data, we conclude that the developing CC plays an important role in the ontogenesis of brain asymmetries. We have extended a previous hypothesis that the rodent CC may exert a stabilizing effect over the unstable populational asymmetries of cortical size and shape, and that it participates in the developmental stabilization of lateralized motor behaviors.
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Pulsed electric fields for pasteurization: defining processing conditions
USDA-ARS?s Scientific Manuscript database
Application of pulsed electric fields (PEF) technology in food pasteurization has been extensively studied. Optimal PEF treatment conditions for maximum microbial inactivation depend on multiple factors including PEF processing conditions, production parameters and product properties. In order for...
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Effect of high hydrostatic pressure on Aeromonas hydrophila AH 191 growth in milk.
Durães-Carvalho, Ricardo; Souza, Ancelmo R; Martins, Luciano M; Sprogis, Adriane C S; Bispo, Jose A C; Bonafe, Carlos F S; Yano, Tomomasa
2012-08-01
Exposure to high pressure is an efficient method of bacterial inactivation that is particularly important for reducing the microbial load present in foods. In this study, we examined the high pressure inactivation of Aeromonas hydrophila AH 191, a virulent strain that produces aerolysin, a cytotoxic, enterotoxic, and hemolytic toxin. High pressure treatment (250 MPa for 30 min at 25 °C in 0.1 M PBS, pH 7.4) of A. hydrophila grown in milk reduced bacterial viability by at least 9 orders of magnitude. Under these conditions, the enterotoxic, hemolytic, and cytotoxic activities of A. hydrophila culture supernatants were unaltered. These results indicate the need for caution in the use of high pressure for food processing since although truly toxigenic bacteria may be inactivated, their toxins may not be, thus posing a risk to human health. At higher pressure (350 MPa) the inactivation of bacteria was much more effective. Scanning electron microscopy showed a significant decrease in the number of bacteria after higher pressurization (350 MPa for 1 h) and transmission electron microscopy showed irregular shaped bacteria, suggestive of important cell wall and membrane damage, and cytoplasm condensation. High pressure inactivates Aeromonas hydrophila efficiently but is enhanced when combined with moderate temperature (40 °C). The biological activities of toxins from this bacterium are unaltered under these conditions. Journal of Food Science © 2012 Institute of Food Technologists® No claim to original US government works.
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Rademaker, Jan L W; Vissers, Marc M M; Te Giffel, Meike C
2007-07-01
The effectiveness of high-temperature, short holding time (HTST) pasteurization and homogenization with respect to inactivation of Mycobacterium avium subsp. paratuberculosis was evaluated quantitatively. This allowed a detailed determination of inactivation kinetics. High concentrations of feces from cows with clinical symptoms of Johne's disease were used to contaminate raw milk in order to realistically mimic possible incidents most closely. Final M. avium subsp. paratuberculosis concentrations varying from 10(2) to 3.5 x 10(5) cells per ml raw milk were used. Heat treatments including industrial HTST were simulated on a pilot scale with 22 different time-temperature combinations, including 60 to 90 degrees C at holding (mean residence) times of 6 to 15 s. Following 72 degrees C and a holding time of 6 s, 70 degrees C for 10 and 15 s, or under more stringent conditions, no viable M. avium subsp. paratuberculosis cells were recovered, resulting in >4.2- to >7.1-fold reductions, depending on the original inoculum concentrations. Inactivation kinetic modeling of 69 quantitative data points yielded an E(a) of 305,635 J/mol and an lnk(0) of 107.2, corresponding to a D value of 1.2 s at 72 degrees C and a Z value of 7.7 degrees C. Homogenization did not significantly affect the inactivation. The conclusion can be drawn that HTST pasteurization conditions equal to 15 s at > or =72 degrees C result in a more-than-sevenfold reduction of M. avium subsp. paratuberculosis.
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Rademaker, Jan L. W.; Vissers, Marc M. M.; te Giffel, Meike C.
2007-01-01
The effectiveness of high-temperature, short holding time (HTST) pasteurization and homogenization with respect to inactivation of Mycobacterium avium subsp. paratuberculosis was evaluated quantitatively. This allowed a detailed determination of inactivation kinetics. High concentrations of feces from cows with clinical symptoms of Johne's disease were used to contaminate raw milk in order to realistically mimic possible incidents most closely. Final M. avium subsp. paratuberculosis concentrations varying from 102 to 3.5 × 105 cells per ml raw milk were used. Heat treatments including industrial HTST were simulated on a pilot scale with 22 different time-temperature combinations, including 60 to 90°C at holding (mean residence) times of 6 to 15 s. Following 72°C and a holding time of 6 s, 70°C for 10 and 15 s, or under more stringent conditions, no viable M. avium subsp. paratuberculosis cells were recovered, resulting in >4.2- to >7.1-fold reductions, depending on the original inoculum concentrations. Inactivation kinetic modeling of 69 quantitative data points yielded an Ea of 305,635 J/mol and an lnk0 of 107.2, corresponding to a D value of 1.2 s at 72°C and a Z value of 7.7°C. Homogenization did not significantly affect the inactivation. The conclusion can be drawn that HTST pasteurization conditions equal to 15 s at ≥72°C result in a more-than-sevenfold reduction of M. avium subsp. paratuberculosis. PMID:17496131
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Bioinactivation: Software for modelling dynamic microbial inactivation.
Garre, Alberto; Fernández, Pablo S; Lindqvist, Roland; Egea, Jose A
2017-03-01
This contribution presents the bioinactivation software, which implements functions for the modelling of isothermal and non-isothermal microbial inactivation. This software offers features such as user-friendliness, modelling of dynamic conditions, possibility to choose the fitting algorithm and generation of prediction intervals. The software is offered in two different formats: Bioinactivation core and Bioinactivation SE. Bioinactivation core is a package for the R programming language, which includes features for the generation of predictions and for the fitting of models to inactivation experiments using non-linear regression or a Markov Chain Monte Carlo algorithm (MCMC). The calculations are based on inactivation models common in academia and industry (Bigelow, Peleg, Mafart and Geeraerd). Bioinactivation SE supplies a user-friendly interface to selected functions of Bioinactivation core, namely the model fitting of non-isothermal experiments and the generation of prediction intervals. The capabilities of bioinactivation are presented in this paper through a case study, modelling the non-isothermal inactivation of Bacillus sporothermodurans. This study has provided a full characterization of the response of the bacteria to dynamic temperature conditions, including confidence intervals for the model parameters and a prediction interval of the survivor curve. We conclude that the MCMC algorithm produces a better characterization of the biological uncertainty and variability than non-linear regression. The bioinactivation software can be relevant to the food and pharmaceutical industry, as well as to regulatory agencies, as part of a (quantitative) microbial risk assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Inactivation of Salmonella and Listeria in ground chicken breast meat during thermal processing.
Murphy, R Y; Marks, B P; Johnson, E R; Johnson, M G
1999-09-01
Thermal inactivation of six Salmonella spp. and Listeria innocua was evaluated in ground chicken breast and liquid medium. Survival of Salmonella and Listeria was affected by the medium composition. Under the same thermal process condition, significantly more Salmonella and Listeria survived in chicken breast meat than in 0.1% peptone-agar solution. The thermal lethality of six tested Salmonella spp. was additive in chicken meat. Survival of Listeria in chicken meat during thermal processing was not affected by the presence of the six Salmonella spp. Sample size and shape affected the inactivation of Salmonella and Listeria in chicken meat during thermal processing.
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Hamprecht, Klaus; Goelz, Rangmar
2017-03-01
Cytomegalovirus (CMV) is reactivated in the lactating breast in up to 96% of CMV seropositive mothers. There is a relevant entity of postnatally acquired symptomatic CMV infection and disease of preterm infants through raw breast milk (BM). Actual data support negative influence on long-term cognitive development. Concerning prevention, only heat inactivation eliminates virus infectivity, and short-term heat inactivation is most preservative; this can be applied effectively under routine conditions. Short-term heat inactivation for 5 minutes at 62°C maintains the benefits of feeding BM without the disadvantages of CMV transmission. Copyright © 2016 Elsevier Inc. All rights reserved.
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ERIC Educational Resources Information Center
Laurent, Vincent; Westbrook, R. Frederick
2009-01-01
Rats were subjected to one or two cycles of context fear conditioning and extinction to study the roles of the prelimbic cortex (PL) and infralimbic cortex (IL) in learning and relearning to inhibit fear responses. Inactivation of the PL depressed fear responses across the first or second extinction but did not impair learning or relearning fear…
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Natural inactivation of Escherichia coli in anaerobic and reduced groundwater.
Lisle, J T
2016-06-01
Inactivation rates of Escherichia coli in groundwater have most often been determined in aerobic and oxidized systems. This study examined E. coli inactivation rates in anaerobic and extremely reduced groundwater systems that have been identified as recharge zones. Groundwater from six artesian wells was diverted to above-ground, flow-through mesocosms that contained laboratory grown E. coli in diffusion chambers. All groundwater was anaerobic and extremely reduced (ORP < -300 mV). Cells were plated onto mTEC agar during 21-day incubation periods. All data fit a bi-phasic inactivation model, with >95% of the E. coli population being inactivated <11·0 h (mean k = 0·488 ±0·188 h(-1) ). The groundwater geochemical conditions enhanced the inactivation of E. coli to rates approx. 21-fold greater than previously published inactivation rate in groundwater (mean k = 0·023 ± 0·030 h(-1) ). Also, mTEC agar inhibits E. coli growth following exposure to anaerobic and reduced groundwater. Aquifer recharge zones with geochemical characteristics observed in this study complement above-ground engineered processes (e.g. filtration, disinfection), while increasing the overall indicator micro-organism log-reduction rate of a facility. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.
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Hippocampal Processing of Ambiguity Enhances Fear Memory
Amadi, Ugwechi; Lim, Seh Hong; Liu, Elizabeth; Baratta, Michael V.; Goosens, Ki Ann
2016-01-01
Despite the ubiquitous use of Pavlovian fear conditioning as a model for fear learning, the highly predictable conditions used in the laboratory do not resemble real-world conditions, where dangerous situations can lead to unpleasant outcomes in unpredictable ways. Here we varied the timing of aversive events following predictive cues in rodents and discovered that temporal ambiguity of aversive events greatly enhances fear. During fear conditioning with unpredictably timed aversive events, pharmacological inactivation of the dorsal hippocampus or optogenetic silencing of CA1 cells during aversive negative prediction errors prevented this enhancement of fear without impacting fear learning for predictable events. Dorsal hippocampal inactivation also prevented ambiguity-related enhancement of fear during auditory fear conditioning under a partial reinforcement schedule. These results reveal that information about the timing and occurrence of aversive events is rapidly acquired and that unexpectedly timed or omitted aversive events generate hippocampal signals to enhance fear learning. PMID:28182526
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Hippocampal Processing of Ambiguity Enhances Fear Memory.
Amadi, Ugwechi; Lim, Seh Hong; Liu, Elizabeth; Baratta, Michael V; Goosens, Ki A
2017-02-01
Despite the ubiquitous use of Pavlovian fear conditioning as a model for fear learning, the highly predictable conditions used in the laboratory do not resemble real-world conditions, in which dangerous situations can lead to unpleasant outcomes in unpredictable ways. In the current experiments, we varied the timing of aversive events after predictive cues in rodents and discovered that temporal ambiguity of aversive events greatly enhances fear. During fear conditioning with unpredictably timed aversive events, pharmacological inactivation of the dorsal hippocampus or optogenetic silencing of cornu ammonis 1 cells during aversive negative prediction errors prevented this enhancement of fear without affecting fear learning for predictable events. Dorsal hippocampal inactivation also prevented ambiguity-related enhancement of fear during auditory fear conditioning under a partial-reinforcement schedule. These results reveal that information about the timing and occurrence of aversive events is rapidly acquired and that unexpectedly timed or omitted aversive events generate hippocampal signals to enhance fear learning.
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Wang, Zhe; Nakayama, Yukiko; Tsuda, Sachiko; Yamasu, Kyo
During vertebrate brain development, the gastrulation brain homeobox 2 gene (gbx2) is expressed in the forebrain, but its precise roles are still unknown. In this study, we addressed this issue in zebrafish (Danio rerio) first by carefully examining gbx2 expression in the developing forebrain. We showed that gbx2 was expressed in the telencephalon during late somitogenesis, from 18h post-fertilization (hpf) to 24 hpf, and in the thalamic primordium after 26 hpf. In contrast, another gbx gene, gbx1, was expressed in the anterior-most ventral telencephalon after 36 hpf. Thus, the expression patterns of these two gbx genes did not overlap, arguing against their redundant function in the forebrain. Two-color fluorescence in situ hybridization (FISH) showed close relationships between the telencephalic expression of gbx2 and other forebrain-forming genes, suggesting that their interactions contribute to the regionalization of the telencephalon. FISH further revealed that gbx2 is expressed in the ventricular region of the telencephalon. By using transgenic fish in which gbx2 can be induced by heat shock, we found that gbx2 induction at 16 hpf repressed the expression of emx3, dlx2a, and six3b in the ventral telencephalon. Among secreted factor genes, bmp2b and wnt1 were repressed in the vicinity of the gbx2 domain in the telencephalon. The expression of forebrain-forming genes was examined in mutant embryos lacking gbx2, showing emx3 and dlx2a to be upregulated in the subpallium at 24 hpf. Taken together, these findings indicate that gbx2 contributes to the development of the subpallium through its repressive activities against other telencephalon-forming genes. We further showed that inhibiting FGF signaling and activating Wnt signaling repressed gbx2 and affected the regionalization of the telencephalon, supporting a functional link between gbx2, intracellular signaling, and telencephalon development. Copyright © 2017 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.
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Poon, Kinning; Alam, Mohammad; Karatayev, Olga; Barson, Jessica R; Leibowitz, Sarah F
2015-12-01
Ingestion of a high-fat diet composed mainly of the saturated fatty acid, palmitic (PA), and the unsaturated fatty acid, oleic (OA), stimulates transcription in the brain of the opioid neuropeptide, enkephalin (ENK), which promotes intake of substances of abuse. To understand possible underlying mechanisms, this study examined the nuclear receptors, peroxisome proliferator-activated receptors (PPARs), and tested in hypothalamic and forebrain neurons from rat embryos whether PPARs regulate endogenous ENK and the fatty acids themselves affect these PPARs and ENK. The first set of experiments demonstrated that knocking down PPARδ, but not PPARα or PPARγ, increased ENK transcription, activation of PPARδ by an agonist decreased ENK levels, and PPARδ neurons coexpressed ENK, suggesting that PPARδ negatively regulates ENK. In the second set of experiments, PA treatment of hypothalamic and forebrain neurons had no effect on PPARδ protein while stimulating ENK mRNA and protein, whereas OA increased both mRNA and protein levels of PPARδ in forebrain neurons while having no effect on ENK mRNA and increasing ENK levels. These findings show that PA has a strong, stimulatory effect on ENK and weak effect on PPARδ protein, whereas OA has a strong stimulatory effect on PPARδ and weak effect on ENK, consistent with the inhibitory effect of PPARδ on ENK. They suggest a function for PPARδ, perhaps protective in nature, in embryonic neurons exposed to fatty acids from a fat-rich diet and provide evidence for a mechanism contributing to differential effects of saturated and monounsaturated fatty acids on neurochemical systems involved in consummatory behavior. Our findings show that PPARδ in forebrain and hypothalamic neurons negatively regulates enkephalin (ENK), a peptide known to promote ingestive behavior. This inverse relationship is consistent with our additional findings, that a saturated (palmitic; PA) compared to a monounsaturated fatty acid (oleic; OA) has a strong stimulatory effect on ENK and weak effect on PPARδ. These results suggest that PPARδ protects against the neuronal effects of fatty acids, which differentially affect neurochemical systems involved in ingestive behavior. © 2015 International Society for Neurochemistry.
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Absence of Prenatal Forebrain Defects in the Dp(16)1Yey/+ Mouse Model of Down Syndrome
Goodliffe, Joseph W.; Olmos-Serrano, Jose Luis; Aziz, Nadine M.; Pennings, Jeroen L.A.; Guedj, Faycal; Bianchi, Diana W.
2016-01-01
Studies in humans with Down syndrome (DS) show that alterations in fetal brain development are followed by postnatal deficits in neuronal numbers, synaptic plasticity, and cognitive and motor function. This same progression is replicated in several mouse models of DS. Dp(16)1Yey/+ (hereafter called Dp16) is a recently developed mouse model of DS in which the entire region of mouse chromosome 16 that is homologous to human chromosome 21 has been triplicated. As such, Dp16 mice may more closely reproduce neurodevelopmental changes occurring in humans with DS. Here, we present the first comprehensive cellular and behavioral study of the Dp16 forebrain from embryonic to adult stages. Unexpectedly, our results demonstrate that Dp16 mice do not have prenatal brain defects previously reported in human fetal neocortex and in the developing forebrains of other mouse models, including microcephaly, reduced neurogenesis, and abnormal cell proliferation. Nevertheless, we found impairments in postnatal developmental milestones, fewer inhibitory forebrain neurons, and deficits in motor and cognitive performance in Dp16 mice. Therefore, although this new model does not express prenatal morphological phenotypes associated with DS, abnormalities in the postnatal period appear sufficient to produce significant cognitive deficits in Dp16. SIGNIFICANCE STATEMENT Down syndrome (DS) leads to intellectual disability. Several mouse models have increased our understanding of the neuropathology of DS and are currently being used to test therapeutic strategies. A new mouse model that contains an expanded number of DS-related genes, known as Dp(16)1Yey/+ (Dp16), has been generated recently. We sought to determine whether the extended triplication creates a better phenocopy of DS-related brain pathologies. We measured embryonic development, forebrain maturation, and perinatal/adult behavior and revealed an absence of prenatal phenotypes in Dp16 fetal brain, but specific cellular and behavioral deficits after the first 2 postnatal weeks. These results uncover important differences in prenatal phenotype between Dp16 animals and humans with DS and other DS mouse models. PMID:26961948
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Selection of Surrogate Bacteria for Use in Food Safety Challenge Studies: A Review.
Hu, Mengyi; Gurtler, Joshua B
2017-09-01
Nonpathogenic surrogate bacteria are prevalently used in a variety of food challenge studies in place of foodborne pathogens such as Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Clostridium botulinum because of safety and sanitary concerns. Surrogate bacteria should have growth characteristics and/or inactivation kinetics similar to those of target pathogens under given conditions in challenge studies. It is of great importance to carefully select and validate potential surrogate bacteria when verifying microbial inactivation processes. A validated surrogate responds similar to the targeted pathogen when tested for inactivation kinetics, growth parameters, or survivability under given conditions in agreement with appropriate statistical analyses. However, a considerable number of food studies involving putative surrogate bacteria lack convincing validation sources or adequate validation processes. Most of the validation information for surrogates in these studies is anecdotal and has been collected from previous publications but may not be sufficient for given conditions in the study at hand. This review is limited to an overview of select studies and discussion of the general criteria and approaches for selecting potential surrogate bacteria under given conditions. The review also includes a list of documented bacterial pathogen surrogates and their corresponding food products and treatments to provide guidance for future studies.
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Hebeisen, Simon; Pires, Nuno; Loureiro, Ana I; Bonifácio, Maria João; Palma, Nuno; Whyment, Andrew; Spanswick, David; Soares-da-Silva, Patrício
2015-02-01
This study aimed at evaluating the effects of eslicarbazepine, carbamazepine (CBZ), oxcarbazepine (OXC) and lacosamide (LCM) on the fast and slow inactivated states of voltage-gated sodium channels (VGSC). The anti-epileptiform activity was evaluated in mouse isolated hippocampal slices. The anticonvulsant effects were evaluated in MES and the 6-Hz psychomotor tests. The whole-cell patch-clamp technique was used to investigate the effects of eslicarbazepine, CBZ, OXC and LCM on sodium channels endogenously expressed in N1E-115 mouse neuroblastoma cells. CBZ and eslicarbazepine exhibit similar concentration dependent suppression of epileptiform activity in hippocampal slices. In N1E-115 mouse neuroblastoma cells, at a concentration of 250 μM, the voltage dependence of the fast inactivation was not influenced by eslicarbazepine, whereas LCM, CBZ and OXC shifted the V0.5 value (mV) by -4.8, -12.0 and -16.6, respectively. Eslicarbazepine- and LCM-treated fast-inactivated channels recovered similarly to control conditions, whereas CBZ- and OXC-treated channels required longer pulses to recover. CBZ, eslicarbazepine and LCM shifted the voltage dependence of the slow inactivation (V0.5, mV) by -4.6, -31.2 and -53.3, respectively. For eslicarbazepine, LCM, CBZ and OXC, the affinity to the slow inactivated state was 5.9, 10.4, 1.7 and 1.8 times higher than to the channels in the resting state, respectively. In conclusion, eslicarbazepine did not share with CBZ and OXC the ability to alter fast inactivation of VGSC. Both eslicarbazepine and LCM reduce VGSC availability through enhancement of slow inactivation, but LCM demonstrated higher interaction with VGSC in the resting state and with fast inactivation gating. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Klitzke, Sondra; Schroeder, Jendrik; Selinka, Hans-Christoph; Szewzyk, Regine; Chorus, Ingrid
2015-06-15
Redox conditions are known to affect the fate of viruses in porous media. Several studies report the relevance of colloid-facilitated virus transport in the subsurface, but detailed studies on the effect of anoxic conditions on virus retention in natural sediments are still missing. Therefore, we investigated the fate of viruses in natural flood plain sediments with different sesquioxide contents under anoxic conditions by considering sorption to the solid phase, sorption to mobilized colloids, and inactivation in the aqueous phase. Batch experiments were conducted under oxic and anoxic conditions at pH values between 5.1 and 7.6, using bacteriophages MS2 and PhiX174 as model viruses. In addition to free and colloid-associated bacteriophages, dissolved and colloidal concentrations of Fe, Al and organic C as well as dissolved Ca were determined. Results showed that regardless of redox conditions, bacteriophages did not adsorb to mobilized colloids, even under favourable charge conditions. Under anoxic conditions, attenuation of bacteriophages was dominated by sorption over inactivation, with MS2 showing a higher degree of sorption than PhiX174. Inactivation in water was low under anoxic conditions for both bacteriophages with about one log10 decrease in concentration during 16 h. Increased Fe/Al concentrations and a low organic carbon content of the sediment led to enhanced bacteriophage removal under anoxic conditions. However, even in the presence of sufficient Fe/A-(hydr)oxides on the solid phase, bacteriophage sorption was low. We presume that organic matter may limit the potential retention of sesquioxides in anoxic sediments and should thus be considered for the risk assessment of virus breakthrough in the subsurface. Copyright © 2015 Elsevier B.V. All rights reserved.
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Matragrano, Lisa L.; Sanford, Sara E.; Salvante, Katrina G.; Beaulieu, Michaël; Sockman, Keith W.; Maney, Donna L.
2011-01-01
Because no organism lives in an unchanging environment, sensory processes must remain plastic so that in any context, they emphasize the most relevant signals. As the behavioral relevance of sociosexual signals changes along with reproductive state, the perception of those signals is altered by reproductive hormones such as estradiol (E2). We showed previously that in white-throated sparrows, immediate early gene responses in the auditory pathway of females are selective for conspecific male song only when plasma E2 is elevated to breeding-typical levels. In this study, we looked for evidence that E2-dependent modulation of auditory responses is mediated by serotonergic systems. In female nonbreeding white-throated sparrows treated with E2, the density of fibers immunoreactive for serotonin transporter innervating the auditory midbrain and rostral auditory forebrain increased compared with controls. E2 treatment also increased the concentration of the serotonin metabolite 5-HIAA in the caudomedial mesopallium of the auditory forebrain. In a second experiment, females exposed to 30 min of conspecific male song had higher levels of 5-HIAA in the caudomedial nidopallium of the auditory forebrain than birds not exposed to song. Overall, we show that in this seasonal breeder, (1) serotonergic fibers innervate auditory areas; (2) the density of those fibers is higher in females with breeding-typical levels of E2 than in nonbreeding, untreated females; and (3) serotonin is released in the auditory forebrain within minutes in response to conspecific vocalizations. Our results are consistent with the hypothesis that E2 acts via serotonin systems to alter auditory processing. PMID:21942431
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Basal forebrain amnesia: does the nucleus accumbens contribute to human memory?
Goldenberg, G.; Schuri, U.; Gromminger, O.; Arnold, U.
1999-01-01
OBJECTIVE—To analyse amnesia caused by basal forebrain lesions. METHODS—A single case study of a patient with amnesia after bleeding into the anterior portion of the left basal ganglia. Neuropsychological examination included tests of attention, executive function, working memory, recall, and recognition of verbal and non-verbal material, and recall from remote semantic and autobiographical memory. The patient's MRI and those of other published cases of basal forebrain amnesia were reviewed to specify which structures within the basal forebrain are crucial for amnesia. RESULTS—Attention and executive function were largely intact. There was anterograde amnesia for verbal material which affected free recall and recognition. With both modes of testing the patient produced many false positive responses and intrusions when lists of unrelated words had been memorised. However, he confabulated neither on story recall nor in day to day memory, nor in recall from remote memory. The lesion affected mainly the nucleus accumbens, but encroached on the inferior limb of the capsula interna and the most ventral portion of the nucleus caudatus and globus pallidus, and there was evidence of some atrophy of the head of the caudate nucleus. The lesion spared the nucleus basalis Meynert, the diagnonal band, and the septum, which are the sites of cholinergic cell concentrations. CONCLUSIONS—It seems unlikely that false positive responses were caused by insufficient strategic control of memory retrieval. This speaks against a major role of the capsular lesion which might disconnect the prefrontal cortex from the thalamus. It is proposed that the lesion of the nucleus accumbens caused amnesia. PMID:10406982
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Poon, Kinning; Alam, Mohammad; Karatayev, Olga; Barson, Jessica R.; Leibowitz, Sarah F.
2015-01-01
Ingestion of a high-fat diet composed mainly of the saturated fatty acid, palmitic (PA), and the unsaturated fatty acid, oleic (OA), stimulates transcription in the brain of the opioid neuropeptide, enkephalin (ENK), which promotes intake of substances of abuse. To understand possible underlying mechanisms, this study examined the nuclear receptors, peroxisome proliferator-activated receptors (PPARs), and tested in hypothalamic and forebrain neurons from rat embryos whether PPARs regulate endogenous ENK and the fatty acids themselves affect these PPARs and ENK. The first set of experiments demonstrated that knocking down PPARδ, but not PPARα or PPARγ, increased ENK transcription, activation of PPARδ by an agonist decreased ENK levels, and PPARδ neurons coexpressed ENK, suggesting that PPARδ negatively regulates ENK. In the second set of experiments, PA treatment of hypothalamic and forebrain neurons had no effect on PPARδ protein while stimulating ENK mRNA and protein, whereas OA increased both mRNA and protein levels of PPARδ in forebrain neurons while having no effect on ENK mRNA and increasing ENK levels. These findings show that PA has a stronger, stimulatory effect on ENK and weaker effect on PPARδ protein, whereas OA has a stronger stimulatory effect on PPARδ and weaker effect on ENK, consistent with the inhibitory effect of PPARδ on ENK. They suggest a function for PPARδ, perhaps protective in nature, in embryonic neurons exposed to fatty acids from a fat-rich diet and provide evidence for a mechanism contributing to differential effects of saturated and monounsaturated fatty acids on neurochemical systems involved in consummatory behavior. PMID:26332891
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Grison, Alice; Gaiser, Carine; Bieder, Andrea; Baranek, Constanze; Atanasoski, Suzana
2018-03-23
Little is known about the molecular players driving proliferation of neural progenitor cells (NPCs) during embryonic mouse development. Here, we demonstrate that proliferation of NPCs in the developing forebrain depends on a particular combination of cell cycle regulators. We have analyzed the requirements for members of the cyclin-dependent kinase (cdk) family using cdk-deficient mice. In the absence of either cdk4 or cdk6, which are both regulators of the G1 phase of the cell cycle, we found no significant effects on the proliferation rate of cortical progenitor cells. However, concomitant loss of cdk4 and cdk6 led to a drastic decrease in the proliferation rate of NPCs, specifically the basal progenitor cells of both the dorsal and ventral forebrain at embryonic day 13.5 (E13.5). Moreover, basal progenitors in the forebrain of Cdk4;Cdk6 double mutant mice exhibited altered cell cycle characteristics. Cdk4;cdk6 deficiency led to an increase in cell cycle length and cell cycle exit of mutant basal progenitor cells in comparison to controls. In contrast, concomitant ablation of cdk2 and cdk6 had no effect on the proliferation of NCPs. Together, our data demonstrate that the expansion of the basal progenitor pool in the developing telencephalon is dependent on the presence of distinct combinations of cdk molecules. Our results provide further evidence for differences in the regulation of proliferation between apical and basal progenitors during cortical development. © 2018 Wiley Periodicals, Inc. Develop Neurobiol, 2018. © 2018 Wiley Periodicals, Inc.
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Desouza, Lynette A; Sathanoori, Malini; Kapoor, Richa; Rajadhyaksha, Neha; Gonzalez, Luis E; Kottmann, Andreas H; Tole, Shubha; Vaidya, Vidita A
2011-05-01
Thyroid hormone is important for development and plasticity in the immature and adult mammalian brain. Several thyroid hormone-responsive genes are regulated during specific developmental time windows, with relatively few influenced across the lifespan. We provide novel evidence that thyroid hormone regulates expression of the key developmental morphogen sonic hedgehog (Shh), and its coreceptors patched (Ptc) and smoothened (Smo), in the early embryonic and adult forebrain. Maternal hypo- and hyperthyroidism bidirectionally influenced Shh mRNA in embryonic forebrain signaling centers at stages before fetal thyroid hormone synthesis. Further, Smo and Ptc expression were significantly decreased in the forebrain of embryos derived from hypothyroid dams. Adult-onset thyroid hormone perturbations also regulated expression of the Shh pathway bidirectionally, with a significant induction of Shh, Ptc, and Smo after hyperthyroidism and a decline in Smo expression in the hypothyroid brain. Short-term T₃ administration resulted in a significant induction of cortical Shh mRNA expression and also enhanced reporter gene expression in Shh(+/LacZ) mice. Further, acute T₃ treatment of cortical neuronal cultures resulted in a rapid and significant increase in Shh mRNA, suggesting direct effects. Chromatin immunoprecipitation assays performed on adult neocortex indicated enhanced histone acetylation at the Shh promoter after acute T₃ administration, providing further support that Shh is a thyroid hormone-responsive gene. Our results indicate that maternal and adult-onset perturbations of euthyroid status cause robust and region-specific changes in the Shh pathway in the embryonic and adult forebrain, implicating Shh as a possible mechanistic link for specific neurodevelopmental effects of thyroid hormone.
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Oelschläger, H A; Northcutt, R G
1992-01-15
Little is known about the immunohistochemistry of the nervous system in bats. This is particularly true of the nervus terminalis, which exerts strong influence on the reproductive system during ontogeny and in the adult. Luteinizing hormone-releasing hormone (LHRH) was visualized immunocytochemically in the nervus terminalis and brain of juvenile and adult big brown bats (Eptesicus fuscus). The peripheral LHRH-immunoreactive (ir) cells and fibers (nervus terminalis) are dispersed along the basal surface of the forebrain from the olfactory bulbs to the prepiriform cortex and the interpeduncular fossa. A concentration of peripheral LHRH-ir perikarya and fibers was found at the caudalmost part of the olfactory bulbs, near the medioventral forebrain sulcus; obviously these cells mediate between the bulbs and the remaining forebrain. Within the central nervous system (CNS), LHRH-ir perikarya and fibers were distributed throughout the olfactory tubercle, diagonal band, preoptic area, suprachiasmatic and supraoptic nuclei, the bed nuclei of stria terminalis and stria medullaris, the anterior lateral and posterior hypothalamus, and the tuber cinereum. The highest concentration of cells was found within the arcuate nucleus. Fibers were most concentrated within the median eminence, infundibular stalk, and the medial habenula. The data obtained suggest that this distribution of LHRH immunoreactivity may be characteristic for microchiropteran (insectivorous) bats. The strong projections of LHRH-containing nuclei in the basal forebrain (including the arcuate nucleus) to the habenula, may indicate close functional contact between these brain areas via feedback loops, which could be important for the processing of thermal and other environmental stimuli correlated with hibernation.
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Sawada, Kazuhiko; Sun, Xue-Zhi; Fukunishi, Katsuhiro; Kashima, Masatoshi; Sakata-Haga, Hiromi; Tokado, Hiroshi; Aoki, Ichio; Fukui, Yoshihiro
2009-09-01
The aim of this study was to spatio-temporally clarify gross structural changes in the forebrain of cynomolgus monkey fetuses using 7-tesla magnetic resonance imaging (MRI). T(1)-weighted coronal, horizontal, and sagittal MR slices of fixed left cerebral hemispheres were obtained from one male fetus at embryonic days (EDs) 70-150. The timetable for fetal sulcation by MRI was in good agreement with that by gross observations, with a lag time of 10-30 days. A difference in detectability of some sulci seemed to be associated with the length, depth, width, and location of the sulci. Furthermore, MRI clarified the embryonic days of the emergence of the callosal (ED 70) and circular (ED 90) sulci, which remained unpredictable under gross observations. Also made visible by the present MRI were subcortical structures of the forebrain such as the caudate nucleus, globus pallidus, putamen, major subdivisions of the thalamus, and hippocampal formation. Their adult-like features were formed by ED 100, corresponding to the onset of a signal enhancement in the gray matter, which reflects neuronal maturation. The results reveal a highly reproducible level of gross structural changes in the forebrain using a high spatial 7-tesla MRI. The present MRI study clarified some changes that are difficult to demonstrate nondestructively using only gross observations, for example, the development of cerebral sulci located on the deep portions of the cortex, as well as cortical and subcortical neuronal maturation.
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Altinay, Serdar; Cabalar, Murat; Isler, Cihan; Yildirim, Funda; Celik, Duygu S; Zengi, Oguzhan; Tas, Abdurrahim; Gulcubuk, Ahmet
2017-01-01
To investigate the neuroprotective effect of chronic curcumin supplementation on the rat forebrain prior to ischemia and reperfusion. Forebrain ischemia was induced by bilateral common carotid artery occlusion for 1/2 hour, followed by reperfusion for 72 hours. Older rats were divided into five groups: Group I received 300 mg/kg oral curcumin for 21 days before ischemia and 300 mg/kg intraperitoneal curcumin after ischemia; Group II received 300 mg/kg intraperitoneal curcumin after ischemia; Group III received 300 mg/kg oral curcumin for 21 days before ischemia; Group IV had only ischemia; Group V was the sham-operated group. The forebrain was rapidly dissected for biochemical parameter assessment and histopathological examination. In forebrain tissue, enzyme activities of superoxide dismutase, glutathione peroxidase, and catalase were significantly higher in Group I than Groups II or III (p < 0.05) while xanthine dehydrogenase and malondialdehyde enzyme activities and concentrations of interleukin-6 and TNF-alpha were significantly lower in Group I when compared to Groups II and III (p < 0.05). A significant reduction in neurological score was observed after 24 and 72 hours in the curcumin-treated groups compared with the ischemic group. We also found a marked reduction in apoptotic index after 72 hours in the groups receiving curcumin. Significantly more TUNEL-positive cells were observed in the ischemic group compared to those treated with curcumin. We demonstrated the neuroprotective effect of chronic curcumin supplement on biochemical parameters, neurological scores and apoptosis following ischemia and reperfusion injury in rats.
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Vonderschen, Katrin; Wagner, Hermann
2012-04-25
Birds and mammals exploit interaural time differences (ITDs) for sound localization. Subsequent to ITD detection by brainstem neurons, ITD processing continues in parallel midbrain and forebrain pathways. In the barn owl, both ITD detection and processing in the midbrain are specialized to extract ITDs independent of frequency, which amounts to a pure time delay representation. Recent results have elucidated different mechanisms of ITD detection in mammals, which lead to a representation of small ITDs in high-frequency channels and large ITDs in low-frequency channels, resembling a phase delay representation. However, the detection mechanism does not prevent a change in ITD representation at higher processing stages. Here we analyze ITD tuning across frequency channels with pure tone and noise stimuli in neurons of the barn owl's auditory arcopallium, a nucleus at the endpoint of the forebrain pathway. To extend the analysis of ITD representation across frequency bands to a large neural population, we employed Fourier analysis for the spectral decomposition of ITD curves recorded with noise stimuli. This method was validated using physiological as well as model data. We found that low frequencies convey sensitivity to large ITDs, whereas high frequencies convey sensitivity to small ITDs. Moreover, different linear phase frequency regimes in the high-frequency and low-frequency ranges suggested an independent convergence of inputs from these frequency channels. Our results are consistent with ITD being remodeled toward a phase delay representation along the forebrain pathway. This indicates that sensory representations may undergo substantial reorganization, presumably in relation to specific behavioral output.
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Neuroregulatory and neuroendocrine GnRH pathways in the hypothalamus and forebrain of the baboon.
Marshall, P E; Goldsmith, P C
1980-07-14
The distribution of neurons containing gonadotropin-releasing hormone (GnRH) in the baboon hypothalamus and forebrain was studied immunocytochemically by light and electron microscopy. GnRH was present in the perikarya, axonal and dendritic processes of immunoreactive neurons. Three populations of GnRH neurons could be distinguished. Most of the GnRH neurons which are assumed to directly influence the anterior pituitary were in the medial basal hypothalamus. Other cells that projected to the median eminence were found scattered throughout the hypothalamus. A second, larger population of neurons apparently was not involved with control of the anterior pituitary. These neurons were generally found within afferent and efferent pathways of the hypothalamus and forebrain, and may receive external information affecting reproduction. A few neurons projecting to the median eminence were also observed sending collaterals to other brain areas. Thus, in addition to their neuroendocrine role, these cells possibly have neuroregulatory functions. The inference is made that these bifunctional neurons, together with the widely observed GnRH-GnRH cellular interactions may help to synchronize ovulation and sexual behavior.
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Agmatine protection against chlorpromazine-induced forebrain cortex injury in rats.
Dejanovic, Bratislav; Stevanovic, Ivana; Ninkovic, Milica; Stojanovic, Ivana; Lavrnja, Irena; Radicevic, Tatjana; Pavlovic, Milos
2016-03-01
This study was conducted to investigate whether agmatine (AGM) provides protection against oxidative stress induced by treatment with chlorpromazine (CPZ) in Wistar rats. In addition, the role of reactive oxygen species and efficiency of antioxidant protection in the brain homogenates of forebrain cortexes prepared 48 h after treatment were investigated. Chlorpromazine was applied intraperitoneally (i.p.) in single dose of 38.7 mg/kg body weight (BW) The second group was treated with both CPZ and AGM (75 mg/kg BW). The control group was treated with 0.9% saline solution in the same manner. All tested compounds were administered i.p. in a single dose. Rats were sacrificed by decapitation 48 h after treatment Treatment with AGM significantly attenuated the oxidative stress parameters and restored antioxidant capacity in the forebrain cortex. The data indicated that i.p. administered AGM exerted antioxidant action in CPZ-treated animals. Moreover, reactive astrocytes and microglia may contribute to secondary nerve-cell damage and participate in the balance of destructive vs. protective actions involved in the pathogenesis after poisoning.
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Hao, Hailing; Li, Ying; Tzatzalos, Evangeline; Gilbert, Jordana; Zala, Dhara; Bhaumik, Mantu; Cai, Li
2014-01-01
Precise control of lineage-specific gene expression in the neural stem/progenitor cells is crucial for generation of the diversity of neuronal and glial cell types in the central nervous system (CNS). The mechanism underlying such gene regulation, however, is not fully elucidated. Here, we report that a 377 bp evolutionarily conserved DNA fragment (CR5), located approximately 32 kbp upstream of Olig2 transcription start site, acts as a cis-regulator for gene expression in the development of the neonatal forebrain. CR5 is active in a time-specific and brain region-restricted manner. CR5 activity is not detected in the embryonic stage, but it is exclusively in a subset of Sox5+ cells in the neonatal ventral forebrain. Furthermore, we show that Sox5 binding motif in CR5 is important for this cell-specific gene regulatory activity; mutation of Sox5 binding motif in CR5 alters reporter gene expression with different cellular composition. Together, our study provides new insights into the regulation of cell-specific gene expression during CNS development. PMID:24954155
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Choe, Youngshik; Zarbalis, Konstantinos S.; Pleasure, Samuel J.
2014-01-01
Embryonic neural crest cells contribute to the development of the craniofacial mesenchyme, forebrain meninges and perivascular cells. In this study, we investigated the function of ß-catenin signaling in neural crest cells abutting the dorsal forebrain during development. In the absence of ß-catenin signaling, neural crest cells failed to expand in the interhemispheric region and produced ectopic smooth muscle cells instead of generating dermal and calvarial mesenchyme. In contrast, constitutive expression of stabilized ß-catenin in neural crest cells increased the number of mesenchymal lineage precursors suggesting that ß-catenin signaling is necessary for the expansion of neural crest-derived mesenchymal cells. Interestingly, the loss of neural crest-derived mesenchymal stem cells (MSCs) leads to failure of telencephalic midline invagination and causes ventricular system defects. This study shows that ß-catenin signaling is required for the switch of neural crest cells to MSCs and mediates the expansion of MSCs to drive the formation of mesenchymal structures of the head. Furthermore, loss of these structures causes striking defects in forebrain morphogenesis. PMID:24516524
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Agmatine protection against chlorpromazine-induced forebrain cortex injury in rats
Stevanovic, Ivana; Ninkovic, Milica; Stojanovic, Ivana; Lavrnja, Irena; Radicevic, Tatjana; Pavlovic, Milos
2016-01-01
This study was conducted to investigate whether agmatine (AGM) provides protection against oxidative stress induced by treatment with chlorpromazine (CPZ) in Wistar rats. In addition, the role of reactive oxygen species and efficiency of antioxidant protection in the brain homogenates of forebrain cortexes prepared 48 h after treatment were investigated. Chlorpromazine was applied intraperitoneally (i.p.) in single dose of 38.7 mg/kg body weight (BW) The second group was treated with both CPZ and AGM (75 mg/kg BW). The control group was treated with 0.9% saline solution in the same manner. All tested compounds were administered i.p. in a single dose. Rats were sacrificed by decapitation 48 h after treatment Treatment with AGM significantly attenuated the oxidative stress parameters and restored antioxidant capacity in the forebrain cortex. The data indicated that i.p. administered AGM exerted antioxidant action in CPZ-treated animals. Moreover, reactive astrocytes and microglia may contribute to secondary nerve-cell damage and participate in the balance of destructive vs. protective actions involved in the pathogenesis after poisoning. PMID:27051340
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Quantitative inactivation-mechanisms of P. digitatum and A. niger spores based on atomic oxygen dose
NASA Astrophysics Data System (ADS)
Ito, Masafumi; Hashizume, Hiroshi; Ohta, Takayuki; Hori, Masaru
2014-10-01
We have investigated inactivation mechanisms of Penicillium digitatum and Asperguills niger spores using atmospheric-pressure radical source quantitatively. The radical source was specially developed for supplying only neutral radicals without charged species and UV-light emissions. Reactive oxygen radical densities such as grand-state oxygen atoms, excited-state oxygen molecules and ozone were measured using VUV and UV absorption spectroscopies. The measurements and the treatments of spores were carried out in an Ar-purged chamber for eliminating the influences of OH, NOx and so on. The results revealed that the inactivation of spores can be explained by atomic-oxygen dose under the conditions employing neutral ROS irradiations. On the basis of the dose, we have observed the changes of intracellular organelles and membrane functions using TEM, SEM and confocal- laser fluorescent microscopy. From these results, we discuss the detail inactivation-mechanisms quantitatively based on atomic-oxygen dose.
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High-pressure processing of apple juice: kinetics of pectin methyl esterase inactivation.
Riahi, Esmaeil; Ramaswamy, Hosahalli S
2003-01-01
High-pressure (HP) inactivation kinetics of pectin methyl esterase (PME) in apple juice were evaluated. Commercial PME was dispensed in clarified apple juice, sealed in dual peel sterilizable plastic bags, and subjected to different high-pressure processing conditions (200-400 MPa, 0-180 min). Residual enzyme activity was determined by a titration method estimating the rate of free carboxyl group released by the enzyme acting on pectin substrate at pH 7.5 (30 degrees C). The effects of pressure level and pressure holding time on enzyme inactivation were significant (p < 0.05). PME from the microbial source was found to be more resistant (p < 0.05) to pressure inactivation than PME from the orange peel. Almost a full decimal reduction in the activity of commercial PME was achieved by HP treatment at 400 MPa for 25 min. Inactivation kinetics were evaluated on the basis of a dual effect model involving a pressure pulse effect and a first-order rate model, and the pressure sensitivity of rate constants was modeled by using the z-value concept.
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Reversible Inactivation and Desiccation Tolerance of Silicified Viruses
DOE Office of Scientific and Technical Information (OSTI.GOV)
Laidler, James J.; Shugart, Jessica A.; Cady, Sherry L.
2013-11-19
Long-distance host-independent virus dispersal is poorly understood, especially for viruses found in isolated ecosystems. To demonstrate a possible dispersal mechanism, we show that bacteriophage T4, archaeal virus SSV-K and Vaccinia are reversibly inactivated by mineralization in silica under conditions similar to volcanic hot springs. By contrast, bacteriophage PRD1 is not silicified. Moreover silicification provides viruses with remarkable desiccation resistance, which could allow extensive aerial dispersal.
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Effect of chelators and nisin produced in situ on inhibition and inactivation of gram negatives.
Boziaris, I S; Adams, M R
1999-12-15
The ability of chelators and nisin generated in situ to inhibit and inactivate E. coli and other gram negatives in a model substrate was investigated. The effect of various chelators and different concentrations of exogenous nisin on inhibition of E. coli in broth medium showed that only EDTA and pyrophosphates were able to cause appreciable inhibition of E. coli by nisin. In a broth where L. lactis NCFB 497 produced nisin in a concentration of 250-300 IU/ml, pyrophosphates were unable to inactivate E. coli. Under the same conditions, addition of EDTA led to inactivation of E. coli at neutral and slightly acidic pH only. A cocktail of strains of E. coli was less sensitive than E. coli ATCC 25922 alone. Pseudomonas aeruginosa was more sensitive and salmonellae more resistant. EDTA also caused a slight reduction in the L. lactis population and its biochemical activity as regards pH drop and acid production. Some of the inhibition of E. coli could be ascribed to the physical presence of Lactococcus cells rather than their metabolites excreted into the medium. Failure to observe any inhibition in fermented broths at their natural pH (4.0) was ascribed to the poor chelating power of EDTA under acid conditions.
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Emerling, Christopher A.; Springer, Mark S.
2015-01-01
Rod monochromacy is a rare condition in vertebrates characterized by the absence of cone photoreceptor cells. The resulting phenotype is colourblindness and low acuity vision in dim-light and blindness in bright-light conditions. Early reports of xenarthrans (armadillos, sloths and anteaters) suggest that they are rod monochromats, but this has not been tested with genomic data. We searched the genomes of Dasypus novemcinctus (nine-banded armadillo), Choloepus hoffmanni (Hoffmann's two-toed sloth) and Mylodon darwinii (extinct ground sloth) for retinal photoreceptor genes and examined them for inactivating mutations. We performed PCR and Sanger sequencing on cone phototransduction genes of 10 additional xenarthrans to test for shared inactivating mutations and estimated the timing of inactivation for photoreceptor pseudogenes. We concluded that a stem xenarthran became an long-wavelength sensitive-cone monochromat following a missense mutation at a critical residue in SWS1, and a stem cingulate (armadillos, glyptodonts and pampatheres) and stem pilosan (sloths and anteaters) independently acquired rod monochromacy early in their evolutionary history following the inactivation of LWS and PDE6C, respectively. We hypothesize that rod monochromacy in armadillos and pilosans evolved as an adaptation to a subterranean habitat in the early history of Xenarthra. The presence of rod monochromacy has major implications for understanding xenarthran behavioural ecology and evolution. PMID:25540280
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Mitroi, Daniel N; Deutschmann, André U; Raucamp, Maren; Karunakaran, Indulekha; Glebov, Konstantine; Hans, Michael; Walter, Jochen; Saba, Julie; Gräler, Markus; Ehninger, Dan; Sopova, Elena; Shupliakov, Oleg; Swandulla, Dieter; van Echten-Deckert, Gerhild
2016-11-24
The bioactive lipid sphingosine 1-phosphate (S1P) is a degradation product of sphingolipids that are particularly abundant in neurons. We have shown previously that neuronal S1P accumulation is toxic leading to ER-stress and an increase in intracellular calcium. To clarify the neuronal function of S1P, we generated brain-specific knockout mouse models in which S1P-lyase (SPL), the enzyme responsible for irreversible S1P cleavage was inactivated. Constitutive ablation of SPL in the brain (SPL fl/fl/Nes ) but not postnatal neuronal forebrain-restricted SPL deletion (SPL fl/fl/CaMK ) caused marked accumulation of S1P. Hence, altered presynaptic architecture including a significant decrease in number and density of synaptic vesicles, decreased expression of several presynaptic proteins, and impaired synaptic short term plasticity were observed in hippocampal neurons from SPL fl/fl/Nes mice. Accordingly, these mice displayed cognitive deficits. At the molecular level, an activation of the ubiquitin-proteasome system (UPS) was detected which resulted in a decreased expression of the deubiquitinating enzyme USP14 and several presynaptic proteins. Upon inhibition of proteasomal activity, USP14 levels, expression of presynaptic proteins and synaptic function were restored. These findings identify S1P metabolism as a novel player in modulating synaptic architecture and plasticity.
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Kou, Xiaoxi; Li, Rui; Hou, Lixia; Zhang, Lihui; Wang, Shaojin
2018-03-23
Radio frequency (RF) heating has been successfully used for inactivating microorganisms in agricultural and food products. Athermal (non-thermal) effects of RF energy on microorganisms have been frequently proposed in the literature, resulting in difficulties for developing effective thermal treatment protocols. The purpose of this study was to identify if the athermal inactivation of microorganisms existed during RF treatments. Escherichia coli and Staphylococcus aureus in apple juice and mashed potato were exposed to both RF and conventional thermal energies to compare their inactivation populations. A thermal death time (TDT) heating block system was used as conventional thermal energy source to simulate the same heating treatment conditions, involving heating temperature, heating rate and uniformity, of a RF treatment at a frequency of 27.12 MHz. Results showed that a similar and uniform temperature distribution in tested samples was achieved in both heating systems, so that the central sample temperature could be used as representative one for evaluating thermal inactivation of microorganisms. The survival patterns of two target microorganisms in two food samples were similar both for RF and heating block treatments since their absolute difference of survival populations was <1 log CFU/ml. The statistical analysis indicated no significant difference (P > 0.05) in inactivating bacteria between the RF and the heating block treatments at each set of temperatures. The solid temperature and microbial inactivation data demonstrated that only thermal effect of RF energy at 27.12 MHz was observed on inactivating microorganisms in foods. Copyright © 2018 Elsevier B.V. All rights reserved.
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Moore, A. L.; Gemel, J.; Randall, D. D.
1993-12-01
The regulation of the pea (Pisum sativum) leaf mitochondrial pyruvate dehydrogenase complex by respiratory rate and oxidative phosphorylation has been investigated by measuring the respiratory activity, the redox poise of the quinone pool (Q-pool), and mitochondrial pyruvate dehydrogenase (mtPDC) activity under various metabolic conditions. It was found that, under state 4 conditions, mtPDC activity was unaffected by either the addition of succinate, 2-oxoglutarate, or glycine or the overall respiratory rate and redox poise of the Q-pool but was partially inhibited by NADH due to product inhibition. In the presence of ADP significant inactivation of PDC, which was sensitive to oligomycin, was observed with all substrates, apart from pyruvate, suggesting that inactivation was due to ATP formation. Inactivation of PDC by ADP addition was observed even in the presence of carboxyatractyloside, an inhibitor of the ATP/ADP translocator, suggesting that other mechanisms to facilitate the entry of adenylates, in addition to the adenylate carrier, must exist in plant mitochondria.
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Atomic Force Microscope Investigations of Bacterial Biofilms Treated with Gas Discharge Plasmas
NASA Astrophysics Data System (ADS)
Vandervoort, Kurt; Zelaya, Anna; Brelles-Marino, Graciela
2012-02-01
We present investigations of bacterial biofilms before and after treatment with gas discharge plasmas. Gas discharge plasmas represent a way to inactivate bacteria under conditions where conventional disinfection methods are often ineffective. These conditions involve biofilm communities, where bacteria grow embedded in an exopolysaccharide matrix, and cooperative interactions between cells make organisms less susceptible to standard inactivation methods. In this study, biofilms formed by the opportunistic bacterium Pseudomonas aeruginosa were imaged before and after plasma treatment using an atomic force microscope (AFM). Through AFM images and micromechanical measurements we observed bacterial morphological damage and reduced AFM tip-sample surface adhesion following plasma treatment.
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NASA Technical Reports Server (NTRS)
Johnson, Alan Kim; Thunhorst, Robert L.
1997-01-01
This review examines recent advances in the study of the behavioral responses to deficits of body water and body sodium that in humans are accompanied by the sensations of thirst and salt appetite. Thirst and salt appetite are satisfied by ingesting water and salty substances. These behavioral responses to losses of body fluids, together with reflex endocrine and neural responses, are critical for reestablishing homeostasis. Like their endocrine and neural counterparts, these behaviors are under the control of both excitatory and inhibitory influences arising from changes in osmolality, endocrine factors such as angiotensin and aldosterone, and neural signals from low and high pressure baroreceptors. The excitatory and inhibitory influences reaching the brain require the integrative capacity of a neural network which includes the structures of the lamina terminalis, the amygdala, the perifornical area, and the paraventricular nucleus in the forebrain, and the lateral parabrachial nucleus (LPBN), the nucleus tractus solitarius (NTS), and the area postrema in the hindbrain. These regions are discussed in terms of their roles in receiving afferent sensory input and in processing information related to hydromineral balance. Osmoreceptors controlling thirst are located in systemic Viscera and in central structures that lack the blood-brain barrier. Angiotensin and aldosterone act on and through structures of the lamina terminalis and the amygdala to stimulate thirst and sodium appetite under conditions of hypovolemia. The NTS and LPBN receive neural signals from baroreceptors and are responsible for inhibiting the ingestion of fluids under conditions of increased volume and pressure and for stimulating thirst under conditions of bypovolemia and hypotension. The interplay of multiple facilitory influences within the brain may take the form of interactions between descending angiotensinergic systems originating in the forebrain and ascending adrenergic systems emanating from the hindbrain. Oxytocin and serotonin are additional candidate neuro- chemicals with postulated inhibitory central actions and with essential roles in the overall integration of sensory input within the neural network devoted to maintaining hydromineral balance.
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Buckow, Roman; Semrau, Julius; Sui, Qian; Wan, Jason; Knoerzer, Kai
2012-01-01
A computational fluid dynamics (CFD) model describing the flow, electric field and temperature distribution of a laboratory-scale pulsed electric field (PEF) treatment chamber with co-field electrode configuration was developed. The predicted temperature increase was validated by means of integral temperature studies using thermocouples at the outlet of each flow cell for grape juice and salt solutions. Simulations of PEF treatments revealed intensity peaks of the electric field and laminar flow conditions in the treatment chamber causing local temperature hot spots near the chamber walls. Furthermore, thermal inactivation kinetics of lactoperoxidase (LPO) dissolved in simulated milk ultrafiltrate were determined with a glass capillary method at temperatures ranging from 65 to 80 °C. Temperature dependence of first order inactivation rate constants was accurately described by the Arrhenius equation yielding an activation energy of 597.1 kJ mol(-1). The thermal impact of different PEF processes on LPO activity was estimated by coupling the derived Arrhenius model with the CFD model and the predicted enzyme inactivation was compared to experimental measurements. Results indicated that LPO inactivation during combined PEF/thermal treatments was largely due to thermal effects, but 5-12% enzyme inactivation may be related to other electro-chemical effects occurring during PEF treatments. Copyright © 2012 American Institute of Chemical Engineers (AIChE).
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Khojasteh, Nasrin Baghban; Pazirandeh, Ali; Jameie, Behnam; Goodarzi, Samereh
2012-06-01
Distribution of (10)B in different regions of rat normal brain was studied. Two groups were chosen as control and trial. Trial group received 2 ml of neutral boron compound. 2, 4 and 6 h after the injection brain removed, coronal sections of forebrain, midbrain and hindbrain were sandwiched between two pieces of polycarbonate. Autoradiography plots of (10)B distribution showed significant differences in three regions with the highest (10)B concentration in the forebrain during 4 h after injection. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Kersigo, Jennifer; D’Angelo, Alex; Gray, Brian; Soukup, Garrett A.; Fritzsch, Bernd
2011-01-01
Cranial development is critically influenced by the relative growth of distinct elements. Previous studies have shown the transcription factor Foxg1 to be expressed is essential for development of telencephalon, olfactory epithelium, parts of the eye and the ear. Here we investigate the effects of a Foxg1-cre mediated conditional deletion of Dicer1 and microRNA (miRNA) on mouse embryos. We report the rapid and complete loss of the telencephalon and cerebellum as well as severe reduction in the ears and loss of the anterior half of the eyes. These losses result in unexpectedly limited malformations of anterodorsal aspects of the skull. We investigated the progressive disappearance of these initially developing structures and found a specific miRNA of nervous tissue, miR-124, to disappear prior to reduction in growth of the specific neurosensory areas. Correlated with the absence of miR-124, these areas showed numerous apoptotic cells that stained positive for anti-cleaved caspase 3 and the phosphatidylserine stain PSVue prior to the near or complete loss of those brain and sensory areas (forebrain, cerebellum, anterior retina, ear). We conclude that Foxg1-cre mediated conditional deletion of Dicer1 leads to absence of functional miRNA followed by complete or nearly complete loss of neurons. Embryonic neurosensory development therefore depends critically on miRNA. Our data suggest that loss of a given neuronal compartment can be triggered using early deletion of Dicer1 and thus provides a novel means to genetically remove specific neurosensory areas to investigate loss of their function on morphology (this study) or signal processing within the brain. PMID:21225654
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Ray, Nicola J; Bradburn, Steven; Murgatroyd, Christopher; Toseeb, Umar; Mir, Pablo; Kountouriotis, George K; Teipel, Stefan J; Grothe, Michel J
2018-01-01
See Gratwicke and Foltynie (doi:10.1093/brain/awx333) for a scientific commentary on this article.Cognitive impairments are a prevalent and disabling non-motor complication of Parkinson's disease, but with variable expression and progression. The onset of serious cognitive decline occurs alongside substantial cholinergic denervation, but imprecision of previously available techniques for in vivo measurement of cholinergic degeneration limit their use as predictive cognitive biomarkers. However, recent developments in stereotactic mapping of the cholinergic basal forebrain have been found useful for predicting cognitive decline in prodromal stages of Alzheimer's disease. These methods have not yet been applied to longitudinal Parkinson's disease data. In a large sample of people with de novo Parkinson's disease (n = 168), retrieved from the Parkinson's Progressive Markers Initiative database, we measured cholinergic basal forebrain volumes, using morphometric analysis of T1-weighted images in combination with a detailed stereotactic atlas of the cholinergic basal forebrain nuclei. Using a binary classification procedure, we defined patients with reduced basal forebrain volumes (relative to age) at baseline, based on volumes measured in a normative sample (n = 76). Additionally, relationships between the basal forebrain volumes at baseline, risk of later cognitive decline, and scores on up to 5 years of annual cognitive assessments were assessed with regression, survival analysis and linear mixed modelling. In patients, smaller volumes in a region corresponding to the nucleus basalis of Meynert were associated with greater change in global cognitive, but not motor scores after 2 years. Using the binary classification procedure, patients classified as having smaller than expected volumes of the nucleus basalis of Meynert had ∼3.5-fold greater risk of being categorized as mildly cognitively impaired over a period of up to 5 years of follow-up (hazard ratio = 3.51). Finally, linear mixed modelling analysis of domain-specific cognitive scores revealed that patients classified as having smaller than expected nucleus basalis volumes showed more severe and rapid decline over up to 5 years on tests of memory and semantic fluency, but not on tests of executive function. Thus, we provide the first evidence that volumetric measurement of the nucleus basalis of Meynert can predict early cognitive decline. Our methods therefore provide the opportunity for multiple-modality biomarker models to include a cholinergic biomarker, which is currently lacking for the prediction of cognitive deterioration in Parkinson's disease. Additionally, finding dissociated relationships between nucleus basalis status and domain-specific cognitive decline has implications for understanding the neural basis of heterogeneity of Parkinson's disease-related cognitive decline. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.
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Wang, Xiang; Lahou, Evy; De Boeck, Elien; Devlieghere, Frank; Geeraerd, Annemie; Uyttendaele, Mieke
2015-01-01
Ground pork meat with natural microbiota and inoculated with low initial densities (1–10 or 10–100 CFU/g) of Salmonella enterica or Listeria monocytogenes was stored under abusive temperature at 10°C and thermally treated by a simulated home pan-frying procedure. The growth and inactivation characteristics were also evaluated in broth. In ground pork meat, the population of S. enterica increased by less than one log after 12-days of storage at 10°C, whereas L. monocytogenes increased by 2.3 to 2.8 log units. No unusual intrinsic heat resistance of the pathogens was noted when tested in broth at 60°C although shoulders were observed on the inactivation curves of L. monocytogenes. After growth of S. enterica and L. monocytogenes at 10°C for 5 days to levels of 1.95 log CFU/g and 3.10 log CFU/g, respectively, in ground pork meat, their inactivation in the burger subjected to a simulated home pan-frying was studied. After thermal treatment S. enterica was undetectable but L. monocytogenes was recovered in three out of six of the 25 g burger samples. Overall, the present study shows that data on growth and inactivation of broths are indicative but may underestimate as well as overestimate behavior of pathogens and thus need confirmation in food matrix conditions to assess food safety in reasonably foreseen abusive conditions of storage and usual home pan-frying of meat burgers in Belgium. PMID:26579079
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González-Tejedor, Gerardo A; Garre, Alberto; Esnoz, A; Artés-Hernández, F; Fernández, P S
2018-06-01
In this study, growth and/or inactivation of Listeria monocytogenes 4032 at different inoculum levels in a vegetable smoothie with purple colour, (previously heat stabilised at 95 °C for 3 min) was evaluated. Growth/inactivation was compared with acidified TSB medium at the same pH level with HCl. Samples were stored at different temperatures (5, 10, 15 and 25 °C). All the smoothies stored at 15 and 25 °C showed growth up to 7.5-8.0 log CFU/mL and at 10 °C growth was only observed at the highest inoculum level. Growth was only observed at 25 °C in acidified TSB. In the case of the smoothies inoculated and stored at 5 °C, L. monocytogenes was not able to grow but survived for a long period of time, whereas at the lower inocula at 10 °C they presented a slow inactivation for an extended time. Acidified TSB inoculated and stored showed inactivation at 5, 10 and 15 °C. Best inactivation modelling alternatives are proposed. The differences between the smoothie and TSB medium about growth or survival in this study, even at relatively low pH values, were due to the favorable nutritional composition of the smoothie compared to a laboratory medium. Results in this study can allow to design safe conditions for smoothie production. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Svoboda, Jan; Lobellová, Veronika; Popelíková, Anna; Ahuja, Nikhil; Kelemen, Eduard; Stuchlík, Aleš
2017-03-01
Although animals often learn and monitor the spatial properties of relevant moving objects such as conspecifics and predators to properly organize their own spatial behavior, the underlying brain substrate has received little attention and hence remains elusive. Because the anterior cingulate cortex (ACC) participates in conflict monitoring and effort-based decision making, and ACC neurons respond to objects in the environment, it may also play a role in the monitoring of moving cues and exerting the appropriate spatial response. We used a robot avoidance task in which a rat had to maintain at least a 25cm distance from a small programmable robot to avoid a foot shock. In successive sessions, we trained ten Long Evans male rats to avoid a fast-moving robot (4cm/s), a stationary robot, and a slow-moving robot (1cm/s). In each condition, the ACC was transiently inactivated by bilateral injections of muscimol in the penultimate session and a control saline injection was given in the last session. Compared to the corresponding saline session, ACC-inactivated rats received more shocks when tested in the fast-moving condition, but not in the stationary or slow robot conditions. Furthermore, ACC-inactivated rats less frequently responded to an approaching robot with appropriate escape responses although their response to shock stimuli remained preserved. Since we observed no effect on slow or stationary robot avoidance, we conclude that the ACC may exert cognitive efforts for monitoring dynamic updating of the position of an object, a role complementary to the dorsal hippocampus. Copyright © 2017 Elsevier Inc. All rights reserved.
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Method for determining virus inactivation during sludge treatment processes.
Traub, F; Spillmann, S K; Wyler, R
1986-01-01
A simple and reliable method is described which allows determination of virus inactivation rates during sludge treatment processes in situ. Bacteriophage f2 was adsorbed onto an electropositive membrane filter which was then sandwiched between two polycarbonate membranes with pores smaller than the virus diameter. The resulting sandwich was fixed in an open filter holder, and several such devices were connected before being exposed in sludge-digesting tanks. The device described prevented uncontrolled virus escape, but allowed direct contact of the various inactivating or stabilizing substances present in the environment tested with the virus adsorbed to the carrier membrane. After exposure to an environment, the surviving fraction of virus was eluted from the inner filter and determined by plaque counting. By using polycarbonate membranes without pores for sandwiching, the influence of temperature alone on virus inactivation could be measured. Thermophilic fermentation at 60 degrees C and at 65 kPa pressure led to a bacteriophage f2 titer reduction of 3.5 log10 units per h, whereas during thermophilic digestion at 54.5 degrees C titers decreased 1.2 log10 units per h. During mesophilic digestion an inactivation rate of only 0.04 log10 units per h was observed. Under these latter conditions, temperature had only a minor effect (19%) on virus inactivation, whereas at 54.5 degrees C during thermophilic digestion heat accounted for 32% of the total inactivation, and during thermophilic fermentation at 60 degrees C temperature and pressure were 100% responsible for virus denaturation. PMID:3532955
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French, Christopher R; Zeng, Zhen; Williams, David A; Hill-Yardin, Elisa L; O'Brien, Terence J
2016-02-01
Rapid transmembrane flow of sodium ions produces the depolarizing phase of action potentials (APs) in most excitable tissue through voltage-gated sodium channels (NaV). Macroscopic currents display rapid activation followed by fast inactivation (IF) within milliseconds. Slow inactivation (IS) has been subsequently observed in several preparations including neuronal tissues. IS serves important physiological functions, but the kinetic properties are incompletely characterized, especially the operative timescales. Here we present evidence for an "intermediate inactivation" (II) process in rat hippocampal CA1 neurons with time constants of the order of 100 ms. The half-inactivation potentials (V0.5) of steady-state inactivation curves were hyperpolarized by increasing conditioning pulse duration from 50 to 500 ms and could be described by a sum of Boltzmann relations. II state transitions were observed after opening as well as subthreshold potentials. Entry into II after opening was relatively insensitive to membrane potential, and recovery of II became more rapid at hyperpolarized potentials. Removal of fast inactivation with cytoplasmic papaine revealed time constants of INa decay corresponding to II and IS with long depolarizations. Dynamic clamp revealed attenuation of trains of APs over the 10(2)-ms timescale, suggesting a functional role of II in repetitive firing accommodation. These experimental findings could be reproduced with a five-state Markov model. It is likely that II affects important aspects of hippocampal neuron response and may provide a drug target for sodium channel modulation. Copyright © 2016 the American Physiological Society.
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Arriaga, Gustavo; Zhou, Eric P.; Jarvis, Erich D.
2012-01-01
Humans and song-learning birds communicate acoustically using learned vocalizations. The characteristic features of this social communication behavior include vocal control by forebrain motor areas, a direct cortical projection to brainstem vocal motor neurons, and dependence on auditory feedback to develop and maintain learned vocalizations. These features have so far not been found in closely related primate and avian species that do not learn vocalizations. Male mice produce courtship ultrasonic vocalizations with acoustic features similar to songs of song-learning birds. However, it is assumed that mice lack a forebrain system for vocal modification and that their ultrasonic vocalizations are innate. Here we investigated the mouse song system and discovered that it includes a motor cortex region active during singing, that projects directly to brainstem vocal motor neurons and is necessary for keeping song more stereotyped and on pitch. We also discovered that male mice depend on auditory feedback to maintain some ultrasonic song features, and that sub-strains with differences in their songs can match each other's pitch when cross-housed under competitive social conditions. We conclude that male mice have some limited vocal modification abilities with at least some neuroanatomical features thought to be unique to humans and song-learning birds. To explain our findings, we propose a continuum hypothesis of vocal learning. PMID:23071596
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Park, Sang-Je; Huh, Jae-Won; Kim, Young-Hyun; Lee, Sang-Rae; Kim, Sang-Hyun; Kim, Sun-Uk; Kim, Heui-Soo; Kim, Min Kyu; Chang, Kyu-Tae
2013-05-01
Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is a specific and sensitive technique for quantifying gene expression. To analyze qRT-PCR data accurately, suitable reference genes that show consistent expression patterns across different tissues and experimental conditions should be selected. The objective of this study was to obtain the most stable reference genes in dogs, using samples from 13 different brain tissues and 10 other organs. 16 well-known candidate reference genes were analyzed by the geNorm, NormFinder, and BestKeeper programs. Brain tissues were derived from several different anatomical regions, including the forebrain, cerebrum, diencephalon, hindbrain, and metencephalon, and grouped accordingly. Combination of the three different analyses clearly indicated that the ideal reference genes are ribosomal protien S5 (RPS5) in whole brain, RPL8 and RPS5 in whole body tissues, RPS5 and RPS19 in the forebrain and cerebrum, RPL32 and RPS19 in the diencephalon, GAPDH and RPS19 in the hindbrain, and MRPS7 and RPL13A in the metencephalon. These genes were identified as ideal for the normalization of qRT-PCR results in the respective tissues. These findings indicate more suitable and stable reference genes for future studies of canine gene expression.
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NMDA Receptors Are Not Required for Pattern Completion During Associative Memory Recall
Gu, Yiran; Cui, Zhenzhong; Tsien, Joe Z.
2011-01-01
Pattern completion, the ability to retrieve complete memories initiated by subsets of external cues, has been a major focus of many computation models. A previously study reports that such pattern completion requires NMDA receptors in the hippocampus. However, such a claim was derived from a non-inducible gene knockout experiment in which the NMDA receptors were absent throughout all stages of memory processes as well as animal's adult life. This raises the critical question regarding whether the previously described results were truly resulting from the requirement of the NMDA receptors in retrieval. Here, we have examined the role of the NMDA receptors in pattern completion via inducible knockout of NMDA receptors limited to the memory retrieval stage. By using two independent mouse lines, we found that inducible knockout mice, lacking NMDA receptor in either forebrain or hippocampus CA1 region at the time of memory retrieval, exhibited normal recall of associative spatial reference memory regardless of whether retrievals took place under full-cue or partial-cue conditions. Moreover, systemic antagonism of NMDA receptor during retention tests also had no effect on full-cue or partial-cue recall of spatial water maze memories. Thus, both genetic and pharmacological experiments collectively demonstrate that pattern completion during spatial associative memory recall does not require the NMDA receptor in the hippocampus or forebrain. PMID:21559402
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Wellman, Cara L; Camp, Marguerite; Jones, V Morgan; MacPherson, Kathryn P; Ihne, Jessica; Fitzgerald, Paul; Maroun, Mouna; Drabant, Emily; Bogdan, Ryan; Hariri, Ahmad R; Holmes, Andrew
2013-12-01
Serotonin is critical for shaping the development of neural circuits regulating emotion. Pet-1 (FEV-1) is an ETS-domain transcription factor essential for differentiation and forebrain targeting of serotonin neurons. Constitutive Pet-1 knockout (KO) causes major loss of serotonin neurons and forebrain serotonin availability, and behavioral abnormalities. We phenotyped Pet-1 KO mice for fear conditioning and extinction, and on a battery of assays for anxiety- and depression-related behaviors. Morphology of Golgi-stained neurons in basolateral amygdala (BLA) and prelimbic cortex was examined. Using human imaging genetics, a common variant (rs860573) in the PET-1 (FEV) gene was tested for effects on threat-related amygdala reactivity and psychopathology in 88 Asian-ancestry subjects. Pet-1 KO mice exhibited increased acquisition and expression of fear, and elevated fear recovery following extinction, relative to wild-type (WT). BLA dendrites of Pet-1 KO mice were significantly longer than in WT. Human PET-1 variation associated with differences in amygdala threat processing and psychopathology. This novel evidence for the role of Pet-1 in fear processing and dendritic organization of amygdala neurons and in human amygdala threat processing extends a growing literature demonstrating the influence of genetic variation in the serotonin system on emotional regulation via effects on structure and function of underlying corticolimbic circuitry. © 2013.
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Effective virus inactivation and removal by steps of Biotest Pharmaceuticals IGIV production process
Dichtelmüller, Herbert O.; Flechsig, Eckhard; Sananes, Frank; Kretschmar, Michael; Dougherty, Christopher J.
2012-01-01
The virus validation of three steps of Biotest Pharmaceuticals IGIV production process is described here. The steps validated are precipitation and removal of fraction III of the cold ethanol fractionation process, solvent/detergent treatment and 35 nm virus filtration. Virus validation was performed considering combined worst case conditions. By these validated steps sufficient virus inactivation/removal is achieved, resulting in a virus safe product. PMID:24371563
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Gene Therapy to Extend Lifespan of Tsc1 Conditional Brain Knockouts
2015-07-01
TSC) is an autosomal genetic disorder which affects about 1 in 6,000 newborns. The disease is caused by inactivating mutations in either of two...are seen in the majority (>90%) of TSC patients, and disrupt neuronal architecture causing epilepsy and obstruction of ventricles, respectively (Short...an autosomal genetic disorder which affects about 1 in 6,000 newborns. The disease is caused by inactivating mutations in either of two related tumor
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ERIC Educational Resources Information Center
Calandreau, Ludovic; Desmedt, Aline; Decorte, Laurence; Jaffard, Robert
2005-01-01
Convergent data suggest dissociated roles for the lateral (LA) and basolateral (BLA) amygdaloid nuclei in fear conditioning, depending on whether a discrete conditioned stimulus (CS)-unconditional stimulus (US) or context-US association is considered. Here, we show that pretraining inactivation of the BLA selectively impaired conditioning to…
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Gene trap and gene inversion methods for conditional gene inactivation in the mouse
Xin, Hong-Bo; Deng, Ke-Yu; Shui, Bo; Qu, Shimian; Sun, Qi; Lee, Jane; Greene, Kai Su; Wilson, Jason; Yu, Ying; Feldman, Morris; Kotlikoff, Michael I.
2005-01-01
Conditional inactivation of individual genes in mice using site-specific recombinases is an extremely powerful method for determining the complex roles of mammalian genes in developmental and tissue-specific contexts, a major goal of post-genomic research. However, the process of generating mice with recombinase recognition sequences placed at specific locations within a gene, while maintaining a functional allele, is time consuming, expensive and technically challenging. We describe a system that combines gene trap and site-specific DNA inversion to generate mouse embryonic stem (ES) cell clones for the rapid production of conditional knockout mice, and the use of this system in an initial gene trap screen. Gene trapping should allow the selection of thousands of ES cell clones with defined insertions that can be used to generate conditional knockout mice, thereby providing extensive parallelism that eliminates the time-consuming steps of targeting vector construction and homologous recombination for each gene. PMID:15659575
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Transcriptional maturation of the mouse auditory forebrain.
Hackett, Troy A; Guo, Yan; Clause, Amanda; Hackett, Nicholas J; Garbett, Krassimira; Zhang, Pan; Polley, Daniel B; Mirnics, Karoly
2015-08-14
The maturation of the brain involves the coordinated expression of thousands of genes, proteins and regulatory elements over time. In sensory pathways, gene expression profiles are modified by age and sensory experience in a manner that differs between brain regions and cell types. In the auditory system of altricial animals, neuronal activity increases markedly after the opening of the ear canals, initiating events that culminate in the maturation of auditory circuitry in the brain. This window provides a unique opportunity to study how gene expression patterns are modified by the onset of sensory experience through maturity. As a tool for capturing these features, next-generation sequencing of total RNA (RNAseq) has tremendous utility, because the entire transcriptome can be screened to index expression of any gene. To date, whole transcriptome profiles have not been generated for any central auditory structure in any species at any age. In the present study, RNAseq was used to profile two regions of the mouse auditory forebrain (A1, primary auditory cortex; MG, medial geniculate) at key stages of postnatal development (P7, P14, P21, adult) before and after the onset of hearing (~P12). Hierarchical clustering, differential expression, and functional geneset enrichment analyses (GSEA) were used to profile the expression patterns of all genes. Selected genesets related to neurotransmission, developmental plasticity, critical periods and brain structure were highlighted. An accessible repository of the entire dataset was also constructed that permits extraction and screening of all data from the global through single-gene levels. To our knowledge, this is the first whole transcriptome sequencing study of the forebrain of any mammalian sensory system. Although the data are most relevant for the auditory system, they are generally applicable to forebrain structures in the visual and somatosensory systems, as well. The main findings were: (1) Global gene expression patterns were tightly clustered by postnatal age and brain region; (2) comparing A1 and MG, the total numbers of differentially expressed genes were comparable from P7 to P21, then dropped to nearly half by adulthood; (3) comparing successive age groups, the greatest numbers of differentially expressed genes were found between P7 and P14 in both regions, followed by a steady decline in numbers with age; (4) maturational trajectories in expression levels varied at the single gene level (increasing, decreasing, static, other); (5) between regions, the profiles of single genes were often asymmetric; (6) GSEA revealed that genesets related to neural activity and plasticity were typically upregulated from P7 to adult, while those related to structure tended to be downregulated; (7) GSEA and pathways analysis of selected functional networks were not predictive of expression patterns in the auditory forebrain for all genes, reflecting regional specificity at the single gene level. Gene expression in the auditory forebrain during postnatal development is in constant flux and becomes increasingly stable with age. Maturational changes are evident at the global through single gene levels. Transcriptome profiles in A1 and MG are distinct at all ages, and differ from other brain regions. The database generated by this study provides a rich foundation for the identification of novel developmental biomarkers, functional gene pathways, and targeted studies of postnatal maturation in the auditory forebrain.
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Koda, Yoichi; Tsuruta, Ryosuke; Fujita, Motoki; Miyauchi, Takashi; Kaneda, Kotaro; Todani, Masaki; Aoki, Tetsuya; Shitara, Masaki; Izumi, Tomonori; Kasaoka, Shunji; Yuasa, Makoto; Maekawa, Tsuyoshi
2010-01-22
The aim of this study was to assess the effect of moderate hypothermia (MH) on generation of jugular venous superoxide radical (O2-.), oxidative stress, early inflammation, and endothelial injury in forebrain ischemia/reperfusion (FBI/R) rats. Twenty-one Wistar rats were allocated to a control group (n=7, 37 degrees C), a pre-MH group (n=7, 32 degrees C before ischemia), and a post-MH group (n=7, 32 degrees C after reperfusion). MH was induced before induction of ischemia in the pre-MH group and just after reperfusion in the post-MH group. Forebrain ischemia was induced by occlusion of bilateral common carotid arteries with hemorrhagic hypotension for 10 min, followed by reperfusion. O(2)(-)(.) in the jugular vein was measured from the produced current using a novel O2-. sensor. The O2-. current showed a gradual increase during forebrain ischemia in the control and post-MH groups but was attenuated in the pre-MH group. Following reperfusion, the current showed a marked increase in the control group but was strongly attenuated in the pre- and post-MH groups. Concentrations of malondialdehyde, high-mobility group box 1 (HMGB1) protein, and intercellular adhesion molecule-1 (ICAM-1) in the brain and plasma 120 min after reperfusion in the pre- and post-MH groups were significantly lower than those in the control group, except for plasma HMGB1 in the post-MH group. In conclusion, MH suppressed O2-. measured in the jugular vein, oxidative stress, early inflammation, and endothelial injury in FBI/R rats. Copyright 2009 Elsevier B.V. All rights reserved.
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Zhang, Chengjin; Ojiaku, Princess; Cole, Gregory J.
2014-01-01
BACKGROUND Ethanol is a teratogen that affects numerous developmental processes in the nervous system, which includes development and survival of GABAergic and glutamatergic neurons. Possible molecular mechanisms accounting for ethanol’s effects on nervous system development include perturbed fibroblast growth factor (Fgf) and Sonic hedgehog (Shh) signaling. In zebrafish, forebrain GABAergic neuron development is dependent on Fgf19 and Shh signaling. The present study was conducted to test the hypothesis that ethanol affects GABAergic and glutamatergic neuron development by disrupting Fgf, Shh, and agrin function. METHODS Zebrafish embryos were exposed to varying concentrations of ethanol during a range of developmental stages, in the absence or presence of morpholino oligonucleotides (MOs) that disrupt agrin or Shh function. In situ hybridization was employed to analyze glutamic acid decarboxylase (GAD1) gene expression, as well as markers of glutamatergic neurons. RESULTS Acute ethanol exposure results in marked reduction in GAD1 gene expression in forebrain and hindbrain, and reduction of glutamatergic neuronal markers in hindbrain. Subthreshold ethanol exposure, combined with agrin or Shh MO treatment, produces a similar diminution in expression of markers for GABAergic and glutamatergic neurons. Consistent with the ethanol effects on Fgf and Shh pathways, Fgf19, Fgf8 or Shh mRNA overexpression rescues ethanol-induced decreases in GAD1 and atonal1a gene expression. CONCLUSIONS These studies demonstrate that GABAergic and glutamatergic neuron development in zebrafish forebrain or cerebellum is sensitive to ethanol exposure, and provides additional evidence that a signaling pathway involving agrin, Fgfs and Shh may be a critical target of ethanol exposure during zebrafish embryogenesis. PMID:23184466
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Bobkova, Natalia; Vorobyov, Vasily; Medvinskaya, Natalia; Nesterova, Inna; Tatarnikova, Olga; Nekrasov, Pavel; Samokhin, Alexander; Deev, Alexander; Sengpiel, Frank; Koroev, Dmitry; Volpina, Olga
2016-01-01
Alzheimer’s disease (AD) is characterized by progressive cognitive impairment associated with marked cholinergic neuron loss and amyloid-β (Aβ) peptide accumulation in the brain. The cytotoxicity in AD is mediated, at least in part, by Aβ binding with the extracellular domain of the p75 neurotrophin receptor (p75NTR), localized predominantly in the membranes of acetylcholine-producing neurons in the basal forebrain. Hypothesizing that an open unstructured loop of p75NTR might be the effective site for Aβ binding, we have immunized both olfactory bulbectomized (OBX) and sham-operated (SO) mice (n = 82 and 49, respectively) with synthetic peptides, structurally similar to different parts of the loops, aiming to block them by specific antibodies. OBX-mice have been shown in previous studies, and confirmed in the present one, to be characterized by typical behavioral, morphological, and biochemical AD hallmarks, including cholinergic deficits in forebrain neurons. Immunization of OBX- or SO-mice with KLH conjugated fragments of p75NTR induced high titers of specific serum antibodies for each of nine chosen fragments. However, maximal protective effects on spatial memory, evaluated in a Morris water maze, and on activity of choline acetyltransferase in forebrain neurons, detected by immunoreactivity to specific antibodies, were revealed only for peptides with amino acid residue sequences of 155–164 and 167–176. We conclude that the approach based on immunological blockade of specific p75NTR sites, linked with the cytotoxicity, is a useful and effective tool for study of AD-associated mechanisms and for development of highly selective therapy of cholinergic malfunctioning in AD patients. PMID:27163825
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Desouza, Lynette A.; Sathanoori, Malini; Kapoor, Richa; Rajadhyaksha, Neha; Gonzalez, Luis E.; Kottmann, Andreas H.; Tole, Shubha
2011-01-01
Thyroid hormone is important for development and plasticity in the immature and adult mammalian brain. Several thyroid hormone-responsive genes are regulated during specific developmental time windows, with relatively few influenced across the lifespan. We provide novel evidence that thyroid hormone regulates expression of the key developmental morphogen sonic hedgehog (Shh), and its coreceptors patched (Ptc) and smoothened (Smo), in the early embryonic and adult forebrain. Maternal hypo- and hyperthyroidism bidirectionally influenced Shh mRNA in embryonic forebrain signaling centers at stages before fetal thyroid hormone synthesis. Further, Smo and Ptc expression were significantly decreased in the forebrain of embryos derived from hypothyroid dams. Adult-onset thyroid hormone perturbations also regulated expression of the Shh pathway bidirectionally, with a significant induction of Shh, Ptc, and Smo after hyperthyroidism and a decline in Smo expression in the hypothyroid brain. Short-term T3 administration resulted in a significant induction of cortical Shh mRNA expression and also enhanced reporter gene expression in Shh+/LacZ mice. Further, acute T3 treatment of cortical neuronal cultures resulted in a rapid and significant increase in Shh mRNA, suggesting direct effects. Chromatin immunoprecipitation assays performed on adult neocortex indicated enhanced histone acetylation at the Shh promoter after acute T3 administration, providing further support that Shh is a thyroid hormone-responsive gene. Our results indicate that maternal and adult-onset perturbations of euthyroid status cause robust and region-specific changes in the Shh pathway in the embryonic and adult forebrain, implicating Shh as a possible mechanistic link for specific neurodevelopmental effects of thyroid hormone. PMID:21363934
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Moltesen, Maria; Laursen, Danielle Caroline; Thörnqvist, Per-Ove; Andersson, Madelene Åberg; Winberg, Svante; Höglund, Erik
2016-12-15
By filtering relevant sensory inputs and initiating stress responses, the brain is an essential organ in stress coping and adaptation. However, exposure to chronic or repeated stress can lead to allostatic overload, where neuroendocrinal and behavioral reactions to stress become maladaptive. This work examines forebrain mechanisms involved in allostatic processes in teleost fishes. Plasma cortisol, forebrain serotonergic (5-HTergic) neurochemistry, and mRNA levels of corticotropin-releasing factor (CRF), CRF-binding protein (CRF-BP), CRF receptors (CRFR1 and CRFR2), mineralocorticoid receptor (MR), glucocorticoid receptors (GR1 and GR2) and serotonin type 1A (5-HT 1A ) receptors (5-HT 1Aα and 5-HT 1Aβ ) were investigated at 1 h before and 0, 1 and 4 h after acute stress, in two groups of rainbow trout held in densities of 25 and 140 kg m -3 for 28 days. Generally, being held at 140 kg m -3 resulted in a less pronounced cortisol response. This effect was also reflected in lower forebrain 5-HTergic turnover, but not in mRNA levels in any of the investigated genes. This lends further support to reports that allostatic load causes fish to be incapable of mounting a proper cortisol response to an acute stressor, and suggests that changes in forebrain 5-HT metabolism are involved in allostatic processes in fish. Independent of rearing densities, mRNA levels of 5-HT 1Aα and MR were downregulated 4 h post-stress compared with values 1 h post-stress, suggesting that these receptors are under feedback control and take part in the downregulation of the hypothalamic-pituitary-interrenal (HPI) axis after exposure to an acute stressor. © 2016. Published by The Company of Biologists Ltd.
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McNamara, Robert K; Schurdak, Jennifer D; Asch, Ruth H; Peters, Bart D; Lindquist, Diana M
2018-01-01
Neuropsychiatric disorders that frequently initially emerge during adolescence are associated with deficits in the omega-3 (n-3) fatty acid docosahexaenoic acid (DHA), elevated proinflammatory signaling, and regional reductions in white matter integrity (WMI). This study determined the effects of altering brain DHA accrual during adolescence on WMI in the rat brain by diffusion tensor imaging (DTI), and investigated the potential mediating role of proinflammatory signaling. During periadolescent development, male rats were fed a diet deficient in n-3 fatty acids (DEF, n = 20), a fish oil-fortified diet containing preformed DHA (FO, n = 20), or a control diet (CON, n = 20). In adulthood, DTI scans were performed and brain WMI was determined using voxelwise tract-based spatial statistics (TBSS). Postmortem fatty acid composition, peripheral (plasma IL-1β, IL-6, and C-reactive protein [CRP]) and central (IL-1β and CD11b mRNA) proinflammatory markers, and myelin basic protein (MBP) mRNA expression were determined. Compared with CON rats, forebrain DHA levels were lower in DEF rats and higher in FO rats. Compared with CON rats, DEF rats exhibited greater radial diffusivity (RD) and mean diffusivity in the right external capsule, and greater axial diffusivity in the corpus callosum genu and left external capsule. DEF rats also exhibited greater RD than FO rats in the right external capsule. Forebrain MBP expression did not differ between groups. Compared with CON rats, central (IL-1β and CD11b) and peripheral (IL-1β and IL-6) proinflammatory markers were not different in DEF rats, and DEF rats exhibited lower CRP levels. These findings demonstrate that deficits in adolescent DHA accrual negatively impact forebrain WMI, independently of elevated proinflammatory signaling. © 2017 S. Karger AG, Basel.
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Effects of lateral fluid percussion injury on cholinergic markers in the newborn piglet brain.
Donat, Cornelius K; Walter, Bernd; Kayser, Tanja; Deuther-Conrad, Winnie; Schliebs, Reinhard; Nieber, Karen; Bauer, Reinhard; Härtig, Wolfgang; Brust, Peter
2010-02-01
Traumatic brain injury is a leading cause of death and disability in children. Studies using adult animal models showed alterations of the central cholinergic neurotransmission as a result of trauma. However, there is a lack of knowledge about consequences of brain trauma on cholinergic function in the immature brain. It is hypothesized that trauma affects the relative acetylcholine esterase activity and causes a loss of cholinergic neurons in the immature brain. Severe fluid percussion trauma (FP-TBI, 3.8+/-0.3atm) was induced in 15 female newborn piglets, monitored for 6h and compared with 12 control animals. The hemispheres ipsilateral to FP-TBI obtained from seven piglets were used for acetylcholine esterase histochemistry on frozen sagittal slices, while regional cerebral blood flow and oxygen availability was determined in the remaining eight FP-TBI animals. Post-fixed slices were immunohistochemically labelled for choline acetyltransferase as well as for low-affinity neurotrophin receptor in order to characterize cholinergic neurons in the basal forebrain. Regional cerebral blood flow and brain oxygen availability were reduced during the first 2h after FP-TBI (P<0.05). In addition, acetylcholine esterase activity was significantly increased in the neocortex, basal forebrain, hypothalamus and medulla after trauma (P<0.05), whereas the number of choline acetyltransferase and low-affinity neurotrophin receptor positive cells in the basal forebrain were unaffected by the injury. Thus, traumatic brain injury evoked an increased relative activity of the acetylcholine esterase in the immature brain early after injury, without loss of cholinergic neurons in the basal forebrain. These changes may contribute to developmental impairments after immature traumatic brain injury. Copyright 2009 ISDN. Published by Elsevier Ltd. All rights reserved.
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Moyano, Paula; Frejo, María Teresa; Anadon, María José; García, José Manuel; Díaz, María Jesús; Lobo, Margarita; Sola, Emma; García, Jimena; Del Pino, Javier
2018-06-01
Chlorpyrifos (CPF) is an organophosphate insecticide described to induce cognitive disorders, both after acute and repeated administration. However, the mechanisms through which it induces these effects are unknown. CPF has been reported to produce basal forebrain cholinergic neuronal cell death, involved on learning and memory regulation, which could be the cause of such cognitive disorders. Neuronal cell death was partially mediated by oxidative stress generation, P75 NTR and α 7 -nAChRs gene expression alteration triggered through acetylcholinesterase (AChE) variants disruption, suggesting other mechanisms are involved. In this regard, CPF induces Aβ and tau proteins production and activation of GSK3β enzyme and alters glutamatergic transmission, which have been related with basal forebrain cholinergic neuronal cell death and development of cognitive disorders. According to these data, we hypothesized that CPF induces basal forebrain cholinergic neuronal cell death through induction of Aβ and tau proteins production, activation of GSK-3β enzyme and disruption of glutamatergic transmission. We evaluated this hypothesis in septal SN56 basal forebrain cholinergic neurons, after 24 h and 14 days CPF exposure. This study shows that CPF increases glutamate levels, upregulates GSK-3β gene expression, and increases the production of Aβ and phosphorylated tau proteins and all these effects reduced cell viability. CPF increases glutaminase activity and upregulates the VGLUT1 gene expression, which could mediate the disruption of glutamatergic transmission. Our present results provide new understanding of the mechanisms contributing to the harmful effects of CPF, and its possible relevance in the pathogenesis of neurodegenerative diseases. Copyright © 2018 Elsevier B.V. All rights reserved.
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MacDonald, Ryan B; Debiais-Thibaud, Mélanie; Martin, Kyle; Poitras, Luc; Tay, Boon-Hui; Venkatesh, Byrappa; Ekker, Marc
2010-05-26
The phylogenetic position of the elephant shark (Callorhinchus milii ) is particularly relevant to study the evolution of genes and gene regulation in vertebrates. Here we examine the evolution of Dlx homeobox gene regulation during vertebrate embryonic development with a particular focus on the forebrain. We first identified the elephant shark sequence orthologous to the URE2 cis -regulatory element of the mouse Dlx1/Dlx2 locus (herein named CmURE2). We then conducted a comparative study of the sequence and enhancer activity of CmURE2 with that of orthologous regulatory sequences from zebrafish and mouse. The CmURE2 sequence shows a high percentage of identity with its mouse and zebrafish counterparts but is overall more similar to mouse URE2 (MmURE2) than to zebrafish URE2 (DrURE2). In transgenic zebrafish and mouse embryos, CmURE2 displayed enhancer activity in the forebrain that overlapped with that of DrURE2 and MmURE2. However, we detected notable differences in the activity of the three sequences in the diencephalon. Outside of the forebrain, CmURE2 shows enhancer activity in areas such as the pharyngeal arches and dorsal root ganglia where its' counterparts are also active. Our transgenic assays show that part of the URE2 enhancer activity is conserved throughout jawed vertebrates but also that new characteristics have evolved in the different groups. Our study demonstrates that the elephant shark is a useful outgroup to study the evolution of regulatory mechanisms in vertebrates and to address how changes in the sequence of cis -regulatory elements translate into changes in their regulatory activity.
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Cid, Mariana Paula; Toledo, Carolina Maribel; Salvatierra, Nancy Alicia
2013-02-01
One-day-old chicks were individually assessed on their latency to peck pebbles, and categorized as low latency (LL) or high latency (HL) according to fear. Interactions between acute stress and systemic insulin and epinephrine on GABA(A) receptor density in the forebrain were studied. At 10 days of life, LL and HL chicks were intraperitoneally injected with insulin, epinephrine or saline, and immediately after stressed by partial water immersion for 15 min and killed by decapitation. Forebrains were dissected and the GABA(A) receptor density was measured ex vivo by the (3)[H]-flunitrazepam binding assay in synaptosomes. In non-stressed chicks, insulin (non-hypoglycemic dose) at 2.50 IU/kg of body weight incremented the Bmax by 40.53% in the HL chicks compared to saline group whereas no significant differences were observed between individuals in the LL subpopulation. Additionally, insulin increased the Bmax (23.48%) in the HL group with respect to the LL ones, indicating that the insulin responses were different according to the anxiety of each category. Epinephrine administration (0.25 and 0.50mg/kg) incremented the Bmax in non-stressed chicks, in the LL group by about 37% and 33%, respectively, compared to ones injected with saline. In the stressed chicks, 0.25mg/kg bw epinephrine increased the Bmax significantly in the HL group by about 24% compared to saline, suggesting that the effect of epinephrine was only observed in the HL group under acute stress conditions. Similarly, the same epinephrine doses co-administered with insulin increased the receptor density in both subpopulations and also showed that the highest dose of epinephrine did not further increase the maximum density of GABA(A)R in HL chicks. These results suggest that systemic epinephrine, perhaps by evoking central norepinephrine release, modulated the increase in the forebrain GABA(A) receptor recruitment induced by both insulin and stress in different ways depending on the subpopulation fearfulness. Copyright © 2013 Elsevier Inc. All rights reserved.
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Selective inactivation of glutaredoxin by sporidesmin and other epidithiopiperazinediones.
Srinivasan, Usha; Bala, Aveenash; Jao, Shu-chuan; Starke, David W; Jordan, T William; Mieyal, John J
2006-07-25
Glutaredoxin (thioltransferase) is a thiol-disulfide oxidoreductase that displays efficient and specific catalysis of protein-SSG deglutathionylation and is thereby implicated in homeostatic regulation of the thiol-disulfide status of cellular proteins. Sporidesmin is an epidithiopiperazine-2,5-dione (ETP) fungal toxin that disrupts cellular functions likely via oxidative alteration of cysteine residues on key proteins. In the current study sporidesmin inactivated human glutaredoxin in a time- and concentration-dependent manner. Under comparable conditions other thiol-disulfide oxidoreductase enzymes, glutathione reductase, thioredoxin, and thioredoxin reductase, were unaffected by sporidesmin. Inactivation of glutaredoxin required the reduced (dithiol) form of the enzyme, the oxidized (intramolecular disulfide) form of sporidesmin, and molecular oxygen. The inactivated glutaredoxin could be reactivated by dithiothreitol only in the presence of urea, followed by removal of the denaturant, indicating that inactivation of the enzyme involves a conformationally inaccessible disulfide bond(s). Various cysteine-to-serine mutants of glutaredoxin were resistant to inactivation by sporidesmin, suggesting that the inactivation reaction specifically involves at least two of the five cysteine residues in human glutaredoxin. The relative ability of various epidithiopiperazine-2,5-diones to inactivate glutaredoxin indicated that at least one phenyl substituent was required in addition to the epidithiodioxopiperazine moiety for inhibitory activity. Mass spectrometry of the modified protein is consistent with formation of intermolecular disulfides, containing one adducted toxin per glutaredoxin but with elimination of two sulfur atoms from the detected product. We suggest that the initial reaction is between the toxin sulfurs and cysteine 22 in the glutaredoxin active site. This study implicates selective modification of sulfhydryls of target proteins in some of the cytotoxic effects of the ETP fungal toxins and their synthetic analogues.
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Setlow, Barbara; Korza, George; Blatt, Kelly M.S.; Fey, Julien P.; Setlow, Peter
2015-01-01
Aims Determine how supercritical CO2 (scCO2) plus peracetic acid (PAA) inactivates Bacillus subtilis spores, factors important in spore resistance to scCO2-PAA, and if spores inactivated by scCO2-PAA are truly dead. Methods and Results Spores of wild-type B. subtilis and isogenic mutants lacking spore protective proteins were treated with scCO2-PAA in liquid or dry at 35°C. Wild-type wet spores (aqueous suspension) were more susceptible than dry spores. Treated spores were examined for viability (and were truly dead), dipicolinic acid (DPA), mutations, permeability to nucleic acid stains, germination under different conditions, energy metabolism and outgrowth. ScCO2-PAA-inactivated spores retained DPA, and survivors had no notable DNA damage. However, DPA was released from inactivated spores at a normally innocuous temperature (85°C), and colony formation from treated spores was salt sensitive. The inactivated spores germinated but did not outgrow, and these germinated spores had altered plasma membrane permeability and defective energy metabolism. Wet or dry coat-defective spores had increased scCO2-PAA sensitivity, and dry spores but not wet spores lacking DNA protective proteins were more scCO2-PAA sensitive. Conclusions These findings suggest that scCO2-PAA inactivates spores by damaging spores’ inner membrane. The spore coat provided scCO2-PAA resistance for both wet and dry spores. DNA protective proteins provided scCO2-PAA resistance only for dry spores. Significance and Impact of Study These results provide information on mechanisms of spore inactivation of and resistance to scCO2-PAA, an agent with increasing use in sterilization applications. PMID:26535794
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Setlow, B; Korza, G; Blatt, K M S; Fey, J P; Setlow, P
2016-01-01
Determine how supercritical CO2 (scCO2 ) plus peracetic acid (PAA) inactivates Bacillus subtilis spores, factors important in spore resistance to scCO2 -PAA, and if spores inactivated by scCO2 -PAA are truly dead. Spores of wild-type B. subtilis and isogenic mutants lacking spore protective proteins were treated with scCO2 -PAA in liquid or dry at 35°C. Wild-type wet spores (aqueous suspension) were more susceptible than dry spores. Treated spores were examined for viability (and were truly dead), dipicolinic acid (DPA), mutations, permeability to nucleic acid stains, germination under different conditions, energy metabolism and outgrowth. ScCO2 -PAA-inactivated spores retained DPA, and survivors had no notable DNA damage. However, DPA was released from inactivated spores at a normally innocuous temperature (85°C), and colony formation from treated spores was salt sensitive. The inactivated spores germinated but did not outgrow, and these germinated spores had altered plasma membrane permeability and defective energy metabolism. Wet or dry coat-defective spores had increased scCO2 -PAA sensitivity, and dry spores but not wet spores lacking DNA protective proteins were more scCO2 -PAA sensitive. These findings suggest that scCO2 -PAA inactivates spores by damaging spores' inner membrane. The spore coat provided scCO2 -PAA resistance for both wet and dry spores. DNA protective proteins provided scCO2 -PAA resistance only for dry spores. These results provide information on mechanisms of spore inactivation of and resistance to scCO2 -PAA, an agent with increasing use in sterilization applications. © 2015 The Society for Applied Microbiology.
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Molecular Viability Testing of UV-Inactivated Bacteria.
Weigel, Kris M; Nguyen, Felicia K; Kearney, Moira R; Meschke, John S; Cangelosi, Gerard A
2017-05-15
PCR is effective in detecting bacterial DNA in samples, but it is unable to differentiate viable bacteria from inactivated cells or free DNA fragments. New PCR-based analytical strategies have been developed to address this limitation. Molecular viability testing (MVT) correlates bacterial viability with the ability to rapidly synthesize species-specific rRNA precursors (pre-rRNA) in response to brief nutritional stimulation. Previous studies demonstrated that MVT can assess bacterial inactivation by chlorine, serum, and low-temperature pasteurization. Here, we demonstrate that MVT can detect inactivation of Escherichia coli , Aeromonas hydrophila , and Enterococcus faecalis cells by UV irradiation. Some UV-inactivated E. coli cells transiently retained the ability to synthesize pre-rRNA postirradiation (generating false-positive MVT results), but this activity ceased within 1 h following UV exposure. Viable but transiently undetectable (by culture) E. coli cells were consistently detected by MVT. An alternative viability testing method, viability PCR (vPCR), correlates viability with cell envelope integrity. This method did not distinguish viable bacteria from UV-inactivated bacteria under some conditions, indicating that the inactivated cells retained intact cell envelopes. MVT holds promise as a means to rapidly assess microbial inactivation by UV treatment. IMPORTANCE UV irradiation is increasingly being used to disinfect water, food, and other materials for human use. Confirming the effectiveness of UV disinfection remains a challenging task. In particular, microbiological methods that rely on rapid detection of microbial DNA can yield misleading results, due to the detection of remnant DNA associated with dead microbial cells. This report describes a novel method that rapidly distinguishes living microbial cells from dead microbial cells after UV disinfection. Copyright © 2017 American Society for Microbiology.
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Wang, B-S; Li, B-S; Du, J-Z; Zeng, Q-X
2015-08-01
This study investigated the inactivation effect and kinetics of Bacillus coagulans and Geobacillus stearothermophilus spores suspended in lu-wei beef by combining high pressure (500 and 600 MPa) and moderate heat (70 and 80 °C or 80 and 90 °C). During pressurization, the temperature of pressure-transmitting fluid was tested with a K-type thermocouple, and the number of surviving cells was determined by a plate count method. The pressure come-up time and corresponding inactivation of Bacillus coagulans and G. stearothermophilus spores were considered during the pressure-thermal treatment. For the two types of spores, the results showed a higher inactivation effect in phosphate buffer solution than that in lu-wei beef. Among the bacteria evaluated, G. stearothermophilus spores had a higher resistance than B. coagulans spores during the pressure-thermal processing. One linear model and two nonlinear models (i.e. the Weibull and log-logistic models) were fitted to the survivor data to obtain relevant kinetic parameters, and the performance of these models was compared. The results suggested that the survival curve of the spores could be accurately described utilizing the log-logistic model, which produced the best fit for all inactivation data. The compression heating characteristics of different pressure-transmitting fluids should be considered when using high pressure to sterilize spores, particularly while the pressure is increasing. Spores can be inactivated by combining high pressure and moderate heat. The study demonstrates the synergistic inactivation effect of moderate heat in combination with high pressure in real-life food. The use of mathematical models to predict the inactivation for spores could help the food industry further to develop optimum process conditions. © 2015 The Society for Applied Microbiology.
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Juliano, Pablo; Knoerzer, Kai; Fryer, Peter J; Versteeg, Cornelis
2009-01-01
High-pressure, high-temperature (HPHT) processing is effective for microbial spore inactivation using mild preheating, followed by rapid volumetric compression heating and cooling on pressure release, enabling much shorter processing times than conventional thermal processing for many food products. A computational thermal fluid dynamic (CTFD) model has been developed to model all processing steps, including the vertical pressure vessel, an internal polymeric carrier, and food packages in an axis-symmetric geometry. Heat transfer and fluid dynamic equations were coupled to four selected kinetic models for the inactivation of C. botulinum; the traditional first-order kinetic model, the Weibull model, an nth-order model, and a combined discrete log-linear nth-order model. The models were solved to compare the resulting microbial inactivation distributions. The initial temperature of the system was set to 90 degrees C and pressure was selected at 600 MPa, holding for 220 s, with a target temperature of 121 degrees C. A representation of the extent of microbial inactivation throughout all processing steps was obtained for each microbial model. Comparison of the models showed that the conventional thermal processing kinetics (not accounting for pressure) required shorter holding times to achieve a 12D reduction of C. botulinum spores than the other models. The temperature distribution inside the vessel resulted in a more uniform inactivation distribution when using a Weibull or an nth-order kinetics model than when using log-linear kinetics. The CTFD platform could illustrate the inactivation extent and uniformity provided by the microbial models. The platform is expected to be useful to evaluate models fitted into new C. botulinum inactivation data at varying conditions of pressure and temperature, as an aid for regulatory filing of the technology as well as in process and equipment design.
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Inactivation of bacteriophage MS2 with potassium ferrate(VI).
Hu, Lanhua; Page, Martin A; Sigstam, Therese; Kohn, Tamar; Mariñas, Benito J; Strathmann, Timothy J
2012-11-06
Ferrate [Fe(VI); FeO(4)(2-)] is an emerging oxidizing agent capable of controlling chemical and microbial water contaminants. Here, inactivation of MS2 coliphage by Fe(VI) was examined. The inactivation kinetics observed in individual batch experiments was well described by a Chick-Watson model with first-order dependences on disinfectant and infective phage concentrations. The inactivation rate constant k(i) at a Fe(VI) dose of 1.23 mgFe/L (pH 7.0, 25 °C) was 2.27(±0.05) L/(mgFe × min), corresponding to 99.99% inactivation at a Ct of ~4 (mgFe × min)/L. Measured k(i) values were found to increase with increasing applied Fe(VI) dose (0.56-2.24 mgFe/L), increasing temperature (5-30 °C), and decreasing pH conditions (pH 6-11). The Fe(VI) dose effect suggested that an unidentified Fe byproduct also contributed to inactivation. Temperature dependence was characterized by an activation energy of 39(±6) kJ mol(-1), and k(i) increased >50-fold when pH decreased from 11 to 6. The pH effect was quantitatively described by parallel reactions with HFeO(4)(-) and FeO(4)(2-). Mass spectrometry and qRT-PCR analyses demonstrated that both capsid protein and genome damage increased with the extent of inactivation, suggesting that both may contribute to phage inactivation. Capsid protein damage, localized in the two regions containing oxidant-sensitive cysteine residues, and protein cleavage in one of the two regions may facilitate genome damage by increasing Fe(VI) access to the interior of the virion.
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Disinfection of bacteriophage MS2 by copper in water.
Armstrong, Andrew M; Sobsey, Mark D; Casanova, Lisa M
2017-09-01
Households that lack piped water supply are often forced to meet water needs by storing in the home, leaving water vulnerable to contamination by viruses. Storage in copper containers can potentially prevent this type of contamination, but the inactivation kinetics of viruses by copper need to be described to make appropriate storage recommendations. This work characterized inactivation kinetics of bacteriophage MS2 as a surrogate for enteric viruses by dissolved ionic copper in water. Reduction of MS2 increased with increasing doses of copper. At 0.3 mg/L, there was a 1.8-log 10 reduction of MS2 within 6 h. At 1 and 3 mg/L, 2-2.5 log 10 inactivation could be achieved between 6 and 24 h. Parameters for the Chick-Watson, Hom, and One Hit-Two Population models of inactivation were calculated and evaluated, all of which demonstrated strong goodness-of-fit and predictability at various contact times. Copper inactivates MS2 under controlled conditions at doses between 0.3 and 3 mg/L. Although requiring longer contact times than conventional disinfectants, it is a candidate for improving the safety of stored drinking water.
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Reactive radical-driven bacterial inactivation by hydrogen-peroxide-enhanced plasma-activated-water
NASA Astrophysics Data System (ADS)
Wu, Songjie; Zhang, Qian; Ma, Ruonan; Yu, Shuang; Wang, Kaile; Zhang, Jue; Fang, Jing
2017-08-01
The combined effects of plasma activated water (PAW) and hydrogen peroxide (H2O2), PAW/HP, in sterilization were investigated in this study. To assess the synergistic effects of PAW/HP, S. aureus was selected as the test microorganism to determine the inactivation efficacy. Also, the DNA/RNA and proteins released by the bacterial suspensions under different conditions were examined to confirm membrane integrity. Additionally, the intracellular pH (pHi) of S. aureus was measured in our study. Electron spin resonance spectroscopy (ESR) was employed to identify the presence of radicals. Finally, the oxidation reduction potential (ORP), conductivity and pH were measured. Our results revealed that the inactivation efficacy of PAW/HP is much greater than that of PAW, while increased H2O2 concentration result in higher inactivation potential. More importantly, as compared with PAW, the much stronger intensity ESR signals and higher ORP in PAW/HP suggests that the inactivation mechanism of the synergistic effects of PAW/HP: more reactive oxygen species (ROS) and reactive nitrogen species (RNS), especially OH and NO radicals, are generated in PAW combined with H2O2 resulting in more deaths of the bacteria.
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Decontamination of prions in a plasma product manufacturing environment.
Bellon, Anne; Comoy, Emmanuel; Simoneau, Steve; Mornac, Sandrine; Dehen, Capucine; Perrin, Audrey; Arzel, Aude; Arrabal, Samuel; Baron, Henry; Laude, Hubert; You, Bruno; Deslys, Jean-Philippe; Flan, Benoit
2014-04-01
The high resistance of prions to inactivating treatments requires the proper management of decontaminating procedures of equipment in contact with materials of human or animal origin destined for medical purposes. Sodium hydroxide (NaOH) is widely used today for this purpose as it inactivates a wide variety of pathogens including prions. Several NaOH treatments were tested on prions bound to either stainless steel or chromatographic resins in industrial conditions with multiple prion strains. Data show a strong correlation between inactivation results obtained by immunochemical detection of the prion protein and those obtained with infectivity assays and establish effective inactivation treatments for prions bound to stainless steel or chromatographic resins (ion exchange and affinity), including treatments with lower NaOH concentrations. Furthermore, no obvious strain-specific behavior difference was observed between experimental models. The results generated by these investigations show that industrial NaOH decontamination regimens (in combination with the NaCl elution in the case of the chromatography process) attain substantial prion inactivation and/or removal between batches, thus providing added assurance to the biologic safety of the final plasma-derived medicinal products. © 2013 American Association of Blood Banks.
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New insight into the residual inactivation of Microcystis aeruginosa by dielectric barrier discharge
Li, Lamei; Zhang, Hong; Huang, Qing
2015-01-01
We report the new insight into the dielectric barrier discharge (DBD) induced inactivation of Microcystis aeruginosa, the dominant algae which caused harmful cyanobacterial blooms in many developing countries. In contrast with the previous work, we employed flow cytometry to examine the algal cells, so that we could assess the dead and living cells with more accuracy, and distinguish an intermediate state of algal cells which were verified as apoptotic. Our results showed that the numbers of both dead and apoptotic cells increased with DBD treatment delay time, and hydrogen peroxide produced by DBD was the main reason for the time-delayed inactivation effect. However, apart from the influence of hydrogen peroxide, the DBD-induced initial injures on the algal cells during the discharge period also played a considerable role in the inactivation of the DBD treated cells, as indicated by the measurement of intracellular reactive oxygen species (ROS) inside the algal cells. We therefore propose an effective approach to utilization of non-thermal plasma technique that makes good use of the residual inactivation effect to optimize the experimental conditions in terms of discharge time and delay time, so that more efficient treatment of cyanobacterial blooms can be achieved. PMID:26347270
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Song, Yurong; Sullivan, Teresa; Klarmann, Kimberly; Gilbert, Debra; O'Sullivan, T Norene; Lu, Lucy; Wang, Sophie; Haines, Diana C; Van Dyke, Terry; Keller, Jonathan R
2017-01-01
Thymic epithelial cells (TEC), as part of thymic stroma, provide essential growth factors/cytokines and self-antigens to support T cell development and selection. Deletion of Rb family proteins in adult thymic stroma leads to T cell hyperplasia in vivo. To determine whether deletion of Rb specifically in keratin (K) 18 positive TEC was sufficient for thymocyte hyperplasia, we conditionally inactivated Rb and its family members p107 and p130 in K18+ TEC in genetically engineered mice (TgK18GT121; K18 mice). We found that thymocyte hyperproliferation was induced in mice with Rb inactivation in K18+ TEC, while normal T cell development was maintained; suggesting that inactivation of Rb specifically in K18+ TEC was sufficient and responsible for the phenotype. Transplantation of wild type bone marrow cells into mice with Rb inactivation in K18+ TEC resulted in donor T lymphocyte hyperplasia confirming the non-cell autonomous requirement for Rb proteins in K18+ TEC in regulating T cell proliferation. Our data suggests that thymic epithelial cells play an important role in regulating lymphoid proliferation and thymus size.
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Lorenzen, Elke; Lee, Geoffrey
2013-12-01
A single-droplet acoustic levitator was used to determine the drying rate and the kinetics of inactivation of glutamate dehydrogenase in the presence of added trehalose or sorbitol. The solution was also spray dried under the same process condition of drying gas temperature on a bench-top machine. Both trehalose and sorbitol delay the point of onset of enzyme inactivation which lies after the critical point of drying. Both carbohydrates also reduce the apparent rate constant of inactivation calculated during the subsequent inactivation phase. The carbohydrates stabilise, therefore, the enzyme during droplet drying and particle formation mainly during the falling rate drying period. There is no difference between the stabilising effects of the two carbohydrates when examined as levitated single droplets. This suggests the importance of water replacement as a stabilising mechanism in the levitated droplets/particles. On spray drying, the trehalose stabilises the enzyme better than does the sorbitol at a drying gas (outlet) temperature of 60°C. This suggests glass formation with the trehalose but not the sorbitol during the very rapid drying process of small-atomised droplets in the spray dryer. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.
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RAGE mediates the inactivation of nAChRs in sympathetic neurons under high glucose conditions.
Chandna, Andrew R; Nair, Manoj; Chang, Christine; Pennington, Paul R; Yamamoto, Yasuhiko; Mousseau, Darrell D; Campanucci, Verónica A
2015-02-01
Autonomic dysfunction is a serious complication of diabetes and can lead to cardiovascular abnormalities and premature death. It was recently proposed that autonomic dysfunction is triggered by oxidation-mediated inactivation of neuronal nicotinic acetylcholine receptors (nAChRs), impairing synaptic transmission in sympathetic ganglia and resulting in autonomic failure. We investigated whether the receptor for advanced glycation end products (RAGE) and its role in the generation of reactive oxygen species (ROS) could be contributing to the events that initiate sympathetic malfunction under high glucose conditions. Using biochemical, live imaging and electrophysiological tools we demonstrated that exposure of sympathetic neurons to high glucose increases RAGE expression and oxidative markers, and that incubation with RAGE ligands (e.g. AGEs, S100 and HMGB1) mimics both ROS elevation and nAChR inactivation. In contrast, co-treatment with either antioxidants or an anti-RAGE IgG prevented the inactivation of nAChRs. Lastly, a role for RAGE in this context was corroborated by the lack of sensitivity of sympathetic neurons from RAGE knock-out mice to high glucose. These data define a pivotal role for RAGE in initiating the events associated with exposure of sympathetic neurons to high glucose, and strongly support RAGE signaling as a potential therapeutic target in the autonomic complications associated with diabetes. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.
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Snider, Gregg W.; Ruggles, Erik; Khan, Nadeem; Hondal, Robert J.
2013-01-01
Mammalian thioredoxin reductase (TR) is a selenocysteine (Sec)-containing homodimeric pyridine nucleotide oxidoreductase which catalyzes the reduction of oxidized thioredoxin. We have previously demonstrated the full-length mitochondrial mammalian TR (mTR3) enzyme to be resistant to inactivation from exposure to 50 mM H2O2. Because a Sec residue oxidizes more rapidly than a cysteine (Cys) residue, it has been previously thought that Sec-containing enzymes are “sensitive to oxidation” compared to Cys-orthologs. Here we show for the first time a direct comparison of the abilities of Sec-containing mTR3 and the Cys-ortholog from D. melanogaster (DmTR) to resist inactivation by oxidation from a variety of oxidants including H2O2, hydroxyl radical, peroxynitrite, hypochlorous acid, hypobromous acid, and hypothiocyanous acid. The results show that the Sec-containing TR is far superior to the Cys-ortholog TR in resisting inactivation by oxidation. To further test our hypothesis that the use of Sec confers strong resistance to inactivation by oxidation, we constructed a chimeric enzyme in which we replaced the active site Cys nucleophile of DmTR with a Sec residue using semisynthesis. The chimeric Sec-containing enzyme has similar ability to resist inactivation by oxidation as the wild type Sec-containing TR from mouse mitochondria. The use of Sec in the chimeric enzyme “rescued” the enzyme from oxidant-induced inactivation for all of the oxidants tested in this study, in direct contrast to previous understanding. We discuss two possibilities for this rescue effect from inactivation under identical conditions of oxidative stress: (i) Sec resists over-oxidation and inactivation, whereas a Cys residue can be permanently over-oxidized to the sulfinic acid form, and (ii) Sec protects the body of the enzyme from harmful oxidation by allowing the enzyme to metabolize (turnover) various oxidants much better than a Cys-containing TR. PMID:23865454
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2016-01-01
Orthologous genes involved in the formation of proteins associated with memory acquisition are similarly expressed in forebrain centres that exhibit similar cognitive properties. These proteins include cAMP-dependent protein kinase A catalytic subunit (PKA-Cα) and phosphorylated Ca2+/calmodulin-dependent protein kinase II (pCaMKII), both required for long-term memory formation which is enriched in rodent hippocampus and insect mushroom bodies, both implicated in allocentric memory and both possessing corresponding neuronal architectures. Antibodies against these proteins resolve forebrain centres, or their equivalents, having the same ground pattern of neuronal organization in species across five phyla. The ground pattern is defined by olfactory or chemosensory afferents supplying systems of parallel fibres of intrinsic neurons intersected by orthogonal domains of afferent and efferent arborizations with local interneurons providing feedback loops. The totality of shared characters implies a deep origin in the protostome–deuterostome bilaterian ancestor of elements of a learning and memory circuit. Proxies for such an ancestral taxon are simple extant bilaterians, particularly acoels that express PKA-Cα and pCaMKII in discrete anterior domains that can be properly referred to as brains. PMID:26598732
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An essential role for LPA signalling in telencephalon development.
Geach, Timothy J; Faas, Laura; Devader, Christelle; Gonzalez-Cordero, Anai; Tabler, Jacqueline M; Brunsdon, Hannah; Isaacs, Harry V; Dale, Leslie
2014-02-01
Lysophosphatidic acid (LPA) has wide-ranging effects on many different cell types, acting through G-protein-coupled receptors such as LPAR6. We show that Xenopus lpar6 is expressed from late blastulae and is enriched in the mesoderm and dorsal ectoderm of early gastrulae. Expression in gastrulae is an early response to FGF signalling. Transcripts for lpar6 are enriched in the neural plate of Xenopus neurulae and loss of function caused forebrain defects, with reduced expression of telencephalic markers (foxg1, emx1 and nkx2-1). Midbrain (en2) and hindbrain (egr2) markers were unaffected. Foxg1 expression requires LPAR6 within ectoderm and not mesoderm. Head defects caused by LPAR6 loss of function were enhanced by co-inhibiting FGF signalling, with defects extending into the hindbrain (en2 and egr2 expression reduced). This is more severe than expected from simple summation of individual defects, suggesting that LPAR6 and FGF have overlapping or partially redundant functions in the anterior neural plate. We observed similar defects in forebrain development in loss-of-function experiments for ENPP2, an enzyme involved in the synthesis of extracellular LPA. Our study demonstrates a role for LPA in early forebrain development.
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Forebrain-selective AMPA-receptor antagonism guided by TARP γ-8 as an antiepileptic mechanism.
Kato, Akihiko S; Burris, Kevin D; Gardinier, Kevin M; Gernert, Douglas L; Porter, Warren J; Reel, Jon; Ding, Chunjin; Tu, Yuan; Schober, Douglas A; Lee, Matthew R; Heinz, Beverly A; Fitch, Thomas E; Gleason, Scott D; Catlow, John T; Yu, Hong; Fitzjohn, Stephen M; Pasqui, Francesca; Wang, He; Qian, Yuewei; Sher, Emanuele; Zwart, Ruud; Wafford, Keith A; Rasmussen, Kurt; Ornstein, Paul L; Isaac, John T R; Nisenbaum, Eric S; Bredt, David S; Witkin, Jeffrey M
2016-12-01
Pharmacological manipulation of specific neural circuits to optimize therapeutic index is an unrealized goal in neurology and psychiatry. AMPA receptors are important for excitatory synaptic transmission, and their antagonists are antiepileptic. Although efficacious, AMPA-receptor antagonists, including perampanel (Fycompa), the only approved antagonist for epilepsy, induce dizziness and motor impairment. We hypothesized that blockade of forebrain AMPA receptors without blocking cerebellar AMPA receptors would be antiepileptic and devoid of motor impairment. Taking advantage of an AMPA receptor auxiliary protein, TARP γ-8, which is selectively expressed in the forebrain and modulates the pharmacological properties of AMPA receptors, we discovered that LY3130481 selectively antagonized recombinant and native AMPA receptors containing γ-8, but not γ-2 (cerebellum) or other TARP members. Two amino acid residues unique to γ-8 determined this selectivity. We also observed antagonism of AMPA receptors expressed in hippocampal, but not cerebellar, tissue from an patient with epilepsy. Corresponding to this selective activity, LY3130481 prevented multiple seizure types in rats and mice and without motor side effects. These findings demonstrate the first rationally discovered molecule targeting specific neural circuitries for therapeutic advantage.
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Cholinergic degeneration and memory loss delayed by vitamin E in a Down syndrome mouse model
Lockrow, Jason; Prakasam, Annamalai; Huang, Peng; Bimonte-Nelson, Heather; Sambamurti, Kumar; Granholm, Ann-Charlotte
2009-01-01
Down syndrome (DS) individuals develop several neuropathological hallmarks seen in Alzheimer's disease, including cognitive decline and the early loss of cholinergic markers in the basal forebrain. These deficits are replicated in the Ts65Dn mouse, which contains a partial trisomy of murine chromosome 16, the orthologous genetic segment to human chromosome 21. Oxidative stress levels are elevated early in DS, and may contribute to the neurodegeneration seen in these individuals. We evaluated oxidative stress in Ts65Dn mice, and assessed the efficacy of long-term antioxidant supplementation on memory and basal forebrain pathology. We report that oxidative stress was elevated in the adult Ts65Dn brain, and that supplementation with the antioxidant vitamin E effectively reduced these markers. Also, Ts65Dn mice receiving vitamin E exhibited improved performance on a spatial working memory task and showed an attenuation of cholinergic neuron pathology in the basal forebrain. This study provides evidence that vitamin E delays onset of cognitive and morphological abnormalities in a mouse model of DS, and may represent a safe and effective treatment early in the progression of DS neuropathology. PMID:19135442
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Birdsong and the neural production of steroids
Remage-Healey, Luke; London, Sarah E.; Schinger, Barney A.
2009-01-01
The forebrain circuits involved in singing and audition (the ‘song system’) in songbirds exhibit a remarkable capacity to synthesize and respond to steroid hormones. This review considers how local brain steroid production impacts the development, sexual differentiation, and activity of song system circuitry. The songbird forebrain contains all of the enzymes necessary for the de novo synthesis of steroids - including neuroestrogens - from cholesterol. Steroid production enzymes are found in neuronal cell bodies, but they are also expressed in pre-synaptic terminals in the song system, indicating a novel mode of brain steroid delivery to local circuits. The song system expresses nuclear hormone receptors, consistent with local action of brain-derived steroids. Local steroid production also occurs in brain regions that do not express nuclear hormone receptors, suggesting a non-classical mode-of-action. Recent evidence indicates that local steroid levels can change rapidly within the forebrain, in a manner similar to traditional neuromodulators. Lastly, we consider growing evidence for modulatory interactions between brain-derived steroids and neurotransmitter/neuropeptide networks within the song system. Songbirds have therefore emerged as a rich and powerful model system to explore the neural and neurochemical regulation of social behavior. PMID:19589382
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Systemic Injections of Cannabidiol Enhance Acetylcholine Levels from Basal Forebrain in Rats.
Murillo-Rodríguez, Eric; Arankowsky-Sandoval, Gloria; Rocha, Nuno Barbosa; Peniche-Amante, Rodrigo; Veras, André Barciela; Machado, Sérgio; Budde, Henning
2018-06-06
Cannabis sativa is a plant that contains more than 500 components, of which the most studied are Δ 9 -tetrahydrocannabinol (Δ 9 -THC) and cannabidiol (CBD). Several studies have indicated that CBD displays neurobiological effects, including wake promotion. Moreover, experimental evidence has shown that injections of CBD enhance wake-related compounds, such as monoamines (dopamine, serotonin, epinephrine, and norepinephrine). However, no clear evidence is available regarding the effects of CBD on additional wake-related neurochemicals such as acetylcholine (ACh). Here, we demonstrate that systemic injections of CBD (0, 5, 10 or 30 mg/kg, i.p.) at the beginning of the lights-on period, increase the extracellular levels of ACh collected from the basal forebrain and measured by microdialysis and HPLC means. Moreover, the time course effects on the contents of ACh were present 5 h post-injection of CBD. Altogether, these data demonstrate that CBD increases ACh levels in a brain region related to wake control. This study is the first to show the effects of ACh levels in CBD-treated rats and suggests that the basal forebrain might be a site of action of CBD for wakefulness modulation.
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Down but Not Out: The Consequences of Pretangle Tau in the Locus Coeruleus
Chalermpalanupap, Termpanit; Weinshenker, David
2017-01-01
Degeneration of locus coeruleus (LC) is an underappreciated hallmark of Alzheimer's disease (AD). The LC is the main source of norepinephrine (NE) in the forebrain, and its degeneration is highly correlated with cognitive impairment and amyloid-beta (Aβ) and tangle pathology. Hyperphosphorylated tau in the LC is among the first detectable AD-like neuropathology in the brain, and while the LC/NE system impacts multiple aspects of AD (e.g., cognition, neuropathology, and neuroinflammation), the functional consequences of hyperphosphorylated tau accrual on LC neurons are not known. Recent evidence suggests that LC neurons accumulate aberrant tau species for decades before frank LC cell body degeneration occurs in AD, suggesting that a therapeutic window exists. In this review, we combine the literature on how pathogenic tau affects forebrain neurons with the known properties and degeneration patterns of LC neurons to synthesize hypotheses on hyperphosphorylated tau-induced dysfunction of LC neurons and the prion-like spread of pretangle tau from the LC to the forebrain. We also propose novel experiments using both in vitro and in vivo models to address the many questions surrounding the impact of hyperphosphorylated tau on LC neurons in AD and its role in disease progression. PMID:29038736
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Sariñana, Joshua; Tonegawa, Susumu
2017-01-01
Activation of prefrontal cortical (PFC), striatal, and hippocampal dopamine 1-class receptors (D1R and D5R) is necessary for normal spatial information processing. Yet the precise role of the D1R versus the D5R in the aforementioned structures, and their specific contribution to the water-maze spatial learning task remains unknown. D1R- and D5R- specific in situ hybridization probes showed that forebrain restricted D1R and D5R KO mice (F-D1R/D5R KO) displayed D1R mRNA deletion in the medial (m)PFC, dorsal and ventral striatum, and the dentate gyrus (DG) of the hippocampus. D5R mRNA deletion was limited to the mPFC, the CA1 and DG hippocampal subregions. F-D1R/D5R KO mice were given water-maze training and displayed subtle spatial latency differences between genotypes and spatial memory deficits during both regular and reversal training. To differentiate forebrain D1R from D5R activation, forebrain restricted D1R KO (F-D1R KO) and D5R KO (F-D5R KO) mice were trained on the water-maze task. F-D1R KO animals exhibited escape latency deficits throughout regular and reversal training as well as spatial memory deficits during reversal training. F-D1R KO mice also showed perseverative behavior during the reversal spatial memory probe test. In contrast, F-D5R KO animals did not present observable deficits on the water-maze task. Because F-D1R KO mice showed water-maze deficits we tested the necessity of hippocampal D1R activation for spatial learning and memory. We trained DG restricted D1R KO (DG-D1R KO) mice on the water-maze task. DG-D1R KO mice did not present detectable spatial memory deficit, but did show subtle deficits during specific days of training. Our data provides evidence that forebrain D5R activation plays a unique role in spatial learning and memory in conjunction with D1R activation. Moreover, these data suggest that mPFC and striatal, but not DG D1R activation are essential for spatial learning and memory. PMID:26174222
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Overexpression of Forebrain CRH During Early Life Increases Trauma Susceptibility in Adulthood
Toth, Mate; Flandreau, Elizabeth I; Deslauriers, Jessica; Geyer, Mark A; Mansuy, Isabelle M; Merlo Pich, Emilio; Risbrough, Victoria B
2016-01-01
Although early-life stress is a significant risk factor for developing anxiety disorders, including posttraumatic stress disorder (PTSD), the underlying mechanisms are unclear. Corticotropin releasing hormone (CRH) is disrupted in individuals with PTSD and early-life stress and hence may mediate the effects of early-life stress on PTSD risk. We hypothesized that CRH hyper-signaling in the forebrain during early development is sufficient to increase response to trauma in adulthood. To test this hypothesis, we induced transient, forebrain-specific, CRH overexpression during early-life (pre-puberty, CRHOEdev) in double-mutant mice (Camk2a-rtta2 × tetO-Crh) and tested their behavioral and gene expression responses to the predator stress model of PTSD in adulthood. In one cohort of CRHOEdev exposed and unexposed mice, avoidance and arousal behaviors were examined 7–15 days after exposure to predator stress. In another cohort, gene expression changes in Crhr1, Crhr2, and Fkbp51 in forebrain of CRHOEdev exposed and unexposed mice were examined 7 days after predator stress. CRHOEdev induced robust increases in startle reactivity and reductions in startle inhibition independently of predator stress in both male and female mice. Avoidance behaviors after predator stress were highly dependent on sex and CRHOEdev exposure. Whereas stressed females exhibited robust avoidance responses that were not altered by CRHOEdev, males developed significant avoidance only when exposed to both CRHOEdev and stress. Quantitative real-time-PCR analysis indicated that CRHOEdev unexposed males exhibit significant changes in Crhr2 expression in the amygdala and bed nucleus stria terminalis in response to stress, whereas males exposed to CRHOEdev did not. Similar to CRHOEdev males, females exhibited no significant Crhr2 gene expression changes in response to stress. Cortical Fkbp51 expression was also significantly reduced by stress and CRHOEdev exposure in males, but not in females. These findings indicate that forebrain CRH hyper-signaling in early-life is sufficient to increase enduring effects of adult trauma and attenuate Crhr2 expression changes in response to stress in males. These data support growing evidence for significant sex differences in response to trauma, and support further study of CRHR2 as a candidate mechanism for PTSD risk. PMID:26538448
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Comparison of cannabinoid binding sites in guinea-pig forebrain and small intestine
Ross, Ruth A; Brockie, Heather C; Fernando, Susanthi R; Saha, Bijali; Razdan, Raj K; Pertwee, Roger G
1998-01-01
We have investigated the nature of cannabinoid receptors in guinea-pig small intestine by establishing whether this tissue contains cannabinoid receptors with similar binding properties to those of brain CB1 receptors. The cannabinoids used were the CB1-selective antagonist SR141716A, the CB2-selective antagonist SR144528, the novel cannabinoid receptor ligand, 6′-azidohex-2′-yne-Δ8-tetrahydrocannabinol (O-1184), and the agonists CP55940, which binds equally well to CB1 and CB2 receptors, and WIN55212-2, which shows marginal CB2 selectivity.[3H]-CP55940 (1 nM) underwent extensive specific binding both to forebrain membranes (76.3%) and to membranes obtained by sucrose density gradient fractionation of homogenates of myenteric plexus-longitudinal muscle of guinea-pig small intestine (65.2%).Its binding capacity (Bmax) was higher in forebrain (4281 fmol mg−1) than in intestinal membranes (2092 fmol mg−1). However, the corresponding KD values were not significantly different from each other (2.29 and 1.75 nM respectively). Nor did the Ki values for its displacement by CP55940, WIN55212-2, O-1184, SR141716A and SR144528 from forebrain membranes (0.87, 4.15, 2.85, 5.32 and 371.9 respectively) differ significantly from the corresponding Ki values determined in experiments with intestinal membranes (0.99, 5.03, 3.16, 4.95 and 361.5 nM respectively).The Bmax values of [3H]-CP55940 and [3H]-SR141716A in forebrain membranes did not differ significantly from each other (4281 and 5658 fmol mg−1) but were both greater than the Bmax of [3H]-WIN55212-2 (2032 fmol mg−1).O-1184 (10 or 100 nM) produced parallel dextral shifts in the log concentration-response curves of WIN55212-2 and CP55940 for inhibition of electrically-evoked contractions of the myenteric plexus-longitudinal muscle preparation, its KD values being 0.20 nM (against WIN55212-2) and 0.89 nM (against CP55940).We conclude that cannabinoid binding sites in guinea-pig small intestine closely resemble CB1 binding sites of guinea-pig brain and that O-1184 behaves as a cannabinoid receptor antagonist in the guinea-pig myenteric plexus-longitudinal muscle preparation. PMID:9863666
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Li, Jun; Han, Baoqing; Ma, Xuesong; Qi, Sihua
2010-10-14
Transient cerebral ischemia may result in neuronal apoptosis. During this process, several apoptosis-regulatory genes are induced in apoptotic cells. Among these genes, cysteinyl aspartate-specific protease-3 (caspase-3) and B-cell leukemia-2 (Bcl-2) are the most effective apoptotic regulators because they play a decisive role in the occurrence of apoptosis. Research has shown that propofol, which is an intravenous anesthetic agent, exhibits neuroprotective effects against cerebral ischemia-reperfusion injury, although the neuroprotective mechanism is still unclear. In this study, we examined the effects of propofol in rats after forebrain ischemia-reperfusion. We assessed the expression of hippocampal caspase-3, which acts as an apoptotic activator, and Bcl-2, which acts as an apoptotic suppressor. Forebrain ischemia was induced in hypotensive rats by clamping the bilateral common carotid arteries for 10 min. Propofol was administered via a lateral cerebral ventricle injection using a microsyringe after the induction of ischemia. Neuronal damage was determined by histological examination of brain sections at the level of the dorsal hippocampus. Caspase-3 and Bcl-2 expression in the hippocampus were detected using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. We also used an immunohistochemical method after ischemia-reperfusion. In the hippocampus, caspase-3 and Bcl-2 mRNA were dramatically increased at 24h after forebrain ischemia. Following 6-24h of reperfusion, forebrain ischemia for 10 min induced a gradual increase in the expression of caspase-3 and Bcl-2 protein in the rat hippocampus, which peaked at 24h. In the propofol (1.0mg/kg) intervention group, the hippocampal expression of caspase-3 mRNA decreased significantly in rats 24h after ischemia; Bcl-2 mRNA was increased at the same time point. During the 24-h reperfusion period and after treatment with propofol, the level of caspase-3 protein expression was low, while the level of Bcl-2 was high. Thus, our results suggest that the neuroprotective effects of propofol against neuronal apoptosis may be mediated by the inhibition of caspase-3 expression and an increase in Bcl-2 expression. Copyright © 2010 Elsevier B.V. All rights reserved.
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Berendsen, Erwin M; Zwietering, Marcel H; Kuipers, Oscar P; Wells-Bennik, Marjon H J
2015-02-01
The survival of bacterial spores after heat treatment and the subsequent germination and outgrowth in a food product can lead to spoilage of the food product and economical losses. Prediction of time-temperature conditions that lead to sufficient inactivation requires access to detailed spore thermal inactivation kinetics of relevant model strains. In this study, the thermal inactivation kinetics of spores of fourteen strains belonging to the Bacillus subtilis group were determined in detail, using both batch heating in capillary tubes and continuous flow heating in a micro heater. The inactivation data were fitted using a log linear model. Based on the spore heat resistance data, two distinct groups (p < 0.001) within the B. subtilis group could be identified. One group of strains had spores with an average D120 °C of 0.33 s, while the spores of the other group displayed significantly higher heat resistances, with an average D120 °C of 45.7 s. When comparing spore inactivation data obtained using batch- and continuous flow heating, the z-values were significantly different, hence extrapolation from one system to the other was not justified. This study clearly shows that heat resistances of spores from different strains in the B. subtilis group can vary greatly. Strains can be separated into two groups, to which different spore heat inactivation kinetics apply. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Dessie, Awrajaw; Alemayehu, Esayas; Mekonen, Seblework; Legesse, Worku; Kloos, Helmut; Ambelu, Argaw
2014-01-10
Disinfection of contaminated water using solar radiation (SODIS) is known to inactivate bacteria. Its inactivation efficiency depends on local conditions where the disinfection is made. This study was aiming to test the efficiency of solar disinfection using different water parameters as low-cost household water treatment technology. Inactivation of microbes was tested using fecal coliform as test organism. The SODIS experiment was carried out at turbidity 2NTU, pH 7, and various water temperature (38.1°C, 41.8°C, 45.6°Cand 51.1°C) and solar intensities, using clear and black plastic bottles filled to different depths. The results show that the rate of microbial inactivation in relation to depth of water, turbidity, container type, intensity of light and color of container was statistically significant (p < 0.05). However, bottle placement, exposure and water pH were unrelated to microbial inactivation. Bacterial re-growth was not observed after solar disinfection. By adjusting the parameters, complete and irreversible fecal coliform inactivation was achieved within an exposure time of less than four hours in the areas where the solar irradiance is about 3.99 kW/m2 and above. Our results indicate that application of SODIS could play a significant role in the provision of safe water in rural communities of developing countries where there is ample sunshine, specifically in sub-Saharan African countries.
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Couture, R; Regoli, D
1981-06-01
The metabolic degradation of substance P(SP), some of its C-terminal fragments, and some analogues by rat plasma has been evaluated from the disappearance of the biological activities of these peptides on the guinea pig isolated ileum. The experiments were performed by dissolving each peptide in saline and by adding 20% (v/v) of rat plasma for incubation at 37 degrees C for various periods of time. It was found that SP and octapeptide 4-11 are inactivated quite rapidly and at approximately the same rate whereas SP-free acid, heptapeptide 5-11, hexapeptide 6-11, and [D-Trp8]-SP are inactivated more slowly. The replacement of Phe7 by D-Trp does not protect the undecapeptide SP from inactivation. The degradation of SP and of all the C-terminal fragments was completely blocked by Captopril at a concentration of 10 micrograms/mL of plasma. Under these conditions, Captopril also slightly reduced the rate of inactivation of bradykinin and of SP-free acid. These results were interpreted as indicative of the presence in rat plasma of an endopeptidase that hydrolyses a peptide bond in the C-terminal pentapeptide sequence of SP. This endopeptidase is completely inactivated by Captopril, which thus appears to be not as specific for the angiotensin-converting enzyme as it was thought to be.
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Dichtelmüller, Herbert O; Biesert, Lothar; Fabbrizzi, Fabrizio; Gajardo, Rodrigo; Gröner, Albrecht; von Hoegen, Ilka; Jorquera, Juan I; Kempf, Christoph; Kreil, Thomas R; Pifat, Dominique; Osheroff, Wendy; Poelsler, Gerhard
2009-09-01
Solvent/detergent (S/D) treatment is an established virus inactivation technology that has been applied in the manufacture of medicinal products derived from human plasma for more than 20 years. Data on the inactivation of enveloped viruses by S/D treatment collected from seven Plasma Protein Therapeutics Association member companies demonstrate the robustness, reliability, and efficacy of this virus inactivation method. The results from 308 studies reflecting production conditions as well as technical variables significantly beyond the product release specification were evaluated for virus inactivation, comprising different combinations of solvent and detergent (tri(n-butyl) phosphate [TNBP]/Tween 80, TNBP/Triton X-100, TNBP/Na-cholate) and different products (Factor [F]VIII, F IX, and intravenous and intramuscular immunoglobulins). Neither product class, process temperature, protein concentration, nor pH value has a significant impact on virus inactivation. A variable that did appear to be critical was the concentration of solvent and detergent. The data presented here demonstrate the robustness of virus inactivation by S/D treatment for a broad spectrum of enveloped test viruses and process variables. Our data substantiate the fact that no transmission of viruses such as human immunodeficiency virus, hepatitis B virus, hepatitis C virus, or of other enveloped viruses was reported for licensed plasma derivatives since the introduction of S/D treatment.
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Inactivation of Mycobacterium avium with free chlorine.
Luh, Jeanne; Mariñas, Benito J
2007-07-15
The inactivation kinetics of Mycobacterium avium with free chlorine was characterized by two stages: an initial phase at a relatively fast rate followed by a slower second stage of pseudo first-order kinetics. The inactivation rate of each stage was approximately the same for all experiments performed at a certain condition of pH and temperature; however, variability was observed for the disinfectant exposure at which the transition between the two stages occurred. This variability was not a function of the initial disinfectant concentration, the initial bacterial density, or the bacterial stock. However, the transition to the second stage varied more significantly at high temperatures (30 degrees C), while lower variability was observed at lower temperatures (5 and 20 degrees C). Experiments conducted at pH values in the range of 6-9 revealed that the inactivation of M. avium was primarily due to hypochlorous acid, with little contribution from hypochlorite ion within this pH range. The inactivation kinetics was represented with a two-population model. The activation energies for the resulting pseudo first-order rate constants for the populations with fast and slow kinetics were 100.3 and 96.5 kJ/mol, respectively. The magnitude of these values suggested that for waters of relatively high pH and low temperatures, little inactivation of M. avium would be achieved within treatment plants, providing a seeding source for distribution systems.
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2014-01-01
Disinfection of contaminated water using solar radiation (SODIS) is known to inactivate bacteria. Its inactivation efficiency depends on local conditions where the disinfection is made. This study was aiming to test the efficiency of solar disinfection using different water parameters as low-cost household water treatment technology. Inactivation of microbes was tested using fecal coliform as test organism. The SODIS experiment was carried out at turbidity 2NTU, pH 7, and various water temperature (38.1°C, 41.8°C, 45.6°Cand 51.1°C) and solar intensities, using clear and black plastic bottles filled to different depths. The results show that the rate of microbial inactivation in relation to depth of water, turbidity, container type, intensity of light and color of container was statistically significant (p < 0.05). However, bottle placement, exposure and water pH were unrelated to microbial inactivation. Bacterial re-growth was not observed after solar disinfection. By adjusting the parameters, complete and irreversible fecal coliform inactivation was achieved within an exposure time of less than four hours in the areas where the solar irradiance is about 3.99 kW/m2 and above. Our results indicate that application of SODIS could play a significant role in the provision of safe water in rural communities of developing countries where there is ample sunshine, specifically in sub-Saharan African countries. PMID:24410979
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Impact of cold plasma on Citrobacter freundii in apple juice: inactivation kinetics and mechanisms.
Surowsky, Björn; Fröhling, Antje; Gottschalk, Nathalie; Schlüter, Oliver; Knorr, Dietrich
2014-03-17
Various studies have shown that cold plasma is capable of inactivating microorganisms located on a variety of food surfaces, food packaging materials and process equipment under atmospheric pressure conditions; however, less attention has been paid to the impact of cold plasma on microorganisms in liquid foodstuffs. The present study investigates cold plasma's ability to inactivate Citrobacter freundii in apple juice. Optical emission spectroscopy (OES) and temperature measurements were performed to characterise the plasma source. The plasma-related impact on microbial loads was evaluated by traditional plate count methods, while morphological changes were determined using scanning electron microscopy (SEM). Physiological property changes were obtained through flow cytometric measurements (membrane integrity, esterase activity and membrane potential). In addition, mathematical modelling was performed in order to achieve a reliable prediction of microbial inactivation and to establish the basis for possible industrial implementation. C. freundii loads in apple juice were reduced by about 5 log cycles after a plasma exposure of 480s using argon and 0.1% oxygen plus a subsequent storage time of 24h. The results indicate that a direct contact between bacterial cells and plasma is not necessary for achieving successful inactivation. The plasma-generated compounds in the liquid, such as H2O2 and most likely hydroperoxy radicals, are particularly responsible for microbial inactivation. Copyright © 2014. Published by Elsevier B.V.
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Turnover-Dependent Inactivation of the Nitrogenase MoFe-Protein at High pH
2013-01-01
Proton uptake accompanies the reduction of all known substrates by nitrogenase. As a consequence, a higher pH should limit the availability of protons as a substrate essential for turnover, thereby increasing the proportion of more highly reduced forms of the enzyme for further study. The utility of the high-pH approach would appear to be problematic in view of the observation reported by Pham and Burgess [(1993) Biochemistry 32, 13725–13731] that the MoFe-protein undergoes irreversible protein denaturation above pH 8.65. In contrast, we found by both enzyme activity and crystallographic analyses that the MoFe-protein is stable when incubated at pH 9.5. We did observe, however, that at higher pHs and under turnover conditions, the MoFe-protein is slowly inactivated. While a normal, albeit low, level of substrate reduction occurs under these conditions, the MoFe-protein undergoes a complex transformation; initially, the enzyme is reversibly inhibited for substrate reduction at pH 9.5, yet in a second, slower process, the MoFe-protein becomes irreversibly inactivated as measured by substrate reduction activity at the optimal pH of 7.8. The final inactivated MoFe-protein has an increased hydrodynamic radius compared to that of the native MoFe-protein, yet it has a full complement of iron and molybdenum. Significantly, the modified MoFe-protein retains the ability to specifically interact with its nitrogenase partner, the Fe-protein, as judged by the support of ATP hydrolysis and by formation of a tight complex with the Fe-protein in the presence of ATP and aluminum fluoride. The turnover-dependent inactivation coupled to conformational change suggests a mechanism-based transformation that may provide a new probe of nitrogenase catalysis. PMID:24392967
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Turnover-dependent inactivation of the nitrogenase MoFe-protein at high pH.
Yang, Kun-Yun; Haynes, Chad A; Spatzal, Thomas; Rees, Douglas C; Howard, James B
2014-01-21
Proton uptake accompanies the reduction of all known substrates by nitrogenase. As a consequence, a higher pH should limit the availability of protons as a substrate essential for turnover, thereby increasing the proportion of more highly reduced forms of the enzyme for further study. The utility of the high-pH approach would appear to be problematic in view of the observation reported by Pham and Burgess [(1993) Biochemistry 32, 13725-13731] that the MoFe-protein undergoes irreversible protein denaturation above pH 8.65. In contrast, we found by both enzyme activity and crystallographic analyses that the MoFe-protein is stable when incubated at pH 9.5. We did observe, however, that at higher pHs and under turnover conditions, the MoFe-protein is slowly inactivated. While a normal, albeit low, level of substrate reduction occurs under these conditions, the MoFe-protein undergoes a complex transformation; initially, the enzyme is reversibly inhibited for substrate reduction at pH 9.5, yet in a second, slower process, the MoFe-protein becomes irreversibly inactivated as measured by substrate reduction activity at the optimal pH of 7.8. The final inactivated MoFe-protein has an increased hydrodynamic radius compared to that of the native MoFe-protein, yet it has a full complement of iron and molybdenum. Significantly, the modified MoFe-protein retains the ability to specifically interact with its nitrogenase partner, the Fe-protein, as judged by the support of ATP hydrolysis and by formation of a tight complex with the Fe-protein in the presence of ATP and aluminum fluoride. The turnover-dependent inactivation coupled to conformational change suggests a mechanism-based transformation that may provide a new probe of nitrogenase catalysis.
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In vitro studies of chlorin e6-assisted photodynamic inactivation of Helicobacter pylori
NASA Astrophysics Data System (ADS)
Simon, C.; Mohrbacher, C.; Hüttenberger, D.; Bauer-Marschall, Ina; Krickhahn, C.; Stachon, A.; Foth, H.-J.
2014-03-01
Helicobacter pylori (HP), a gram-negative microaerophilic bacterium located in gastric mucosa, plays an im- portant role in gastro carcinogenesis. Due to the increasing emergence of antibiotic resistance, photodynamic inactivation of bacteria presents a new approach to treat bacterial infections, like HP. In vitro experiments were performed to determine the irradiation conditions for a complete inactivation of HP with the photosensitizer Chlorin e6 (Ce6). The HP strain CCUG 38770 (Culture Collection, University of Gothenburg, Sweden) was routinely cultured under microaerophilic conditions, suspended in sodium chloride, incubated with Ce6 and irradiated briefly with red light of the appropriate wavelength of λ = 660 nm. Series of measurements of different Ce6-concentrations (0.1 μM - 100 μM) were carried out, whereby the incubation time was kept constant at 1 min. The absorbed energy dose has been selected in varying the irradiation time (1 s - 300 s) and the power density (4.5 mW/cm2 - 31 mW/cm2 ). Quantification of inactivation was performed by enumeration of the grown colonies. In addition, the accumulation of Ce6 in HP cells was studied more precisely by uorescence spectroscopy. With a Ce6 concentration of 100 μM and a power density of 9 mW cm2 , a 6-log10 reduction in the survival rate of HP was achieved within 30 seconds of irradiation. In conclusion the most relevant factor for the inactivation of HP is the exposure time of irradiation, followed by the concentration of Ce6 and the light intensity. Further studies with HP strains obtained from patient specimens are under current investigation.
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Dang, Loc T T; Imai, Tsuyoshi; Le, Tuan V; Nishihara, Satoshi; Higuchi, Takaya; Nguyen, Mai K D; Kanno, Ariyo; Yamamoto, Koichi; Sekine, Masahiko
2016-09-18
Interest is growing in a disinfection technique for water treatment without disinfection byproducts. This study presents the result of using a liquid-film-forming apparatus at less than 1.0 MPa for disinfection of seawater. The sensitivity of Enterococcus sp. (ATCC 202155) to the pressurized carbon dioxide (CO2) was examined under various conditions of pressure cycling, pressure, working volume ratio (WVR), and CO2 content rate. The key influences on frequency and magnitude of pressure cycling in enhancing Enterococcus sp. inactivation are elucidated. The results reveal strong correlation between pressure cycling and inactivation efficiency (P-value < 0.001). The outcome of linear regression model analysis suggests that the model can explain 93%, 85%, and 89% of the inactivation efficiency of (25% CO2 + 75% N2), (50% CO2 + 50% N2), and 100% CO2, respectively. The predicted value was fit with experimental results (p-value <0.05). Under identical treatment conditions (pressure = 0.9 MPa, ΔP = 0.14 MPa, 70% WVR, and 20 ± 1°C), treatment with pressurized CO2 (100% purity) resulted in complete inactivation 5.2 log of Enterococcus sp. after 70 cycles within 20 min. The Enterococcus sp. inactivation of pressurized CO2 followed first-order reaction kinetics. The smallest D-value (largest k-value) was induced by pressurized CO2 (100% purity) at 0.9 MPa, which was obtained at 3.85 min (0.5988 min(-1), R(2) ≥ 0.95). The findings could provide an effective method for enhanced bactericidal performance of pressurized CO2, to address recently emerging problems in water disinfection.
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Amin, Muhammad T.; Nawaz, Mohsin; Amin, Muhammad N.; Han, Mooyoung
2014-01-01
Efficiency of solar based disinfection of Pseudomonas aeruginosa (P. aeruginosa) in rooftop harvested rainwater was evaluated aiming the potability of rainwater. The rainwater samples were exposed to direct sunlight for about 8–9 hours and the effects of water temperature (°C), sunlight irradiance (W/m2), different rear surfaces of polyethylene terephthalate bottles, variable microbial concentrations, pH and turbidity were observed on P. aeruginosa inactivation at different weathers. In simple solar disinfection (SODIS), the complete inactivation of P. aeruginosa was obtained only under sunny weather conditions (>50°C and >700 W/m2) with absorptive rear surface. Solar collector disinfection (SOCODIS) system, used to improve the efficiency of simple SODIS under mild and weak weather, completely inactivated the P. aeruginosa by enhancing the disinfection efficiency of about 20% only at mild weather. Both SODIS and SOCODIS systems, however, were found inefficient at weak weather. Different initial concentrations of P. aeruginosa and/or Escherichia coli had little effects on the disinfection efficiency except for the SODIS with highest initial concentrations. The inactivation of P. aeruginosa increased by about 10–15% by lowering the initial pH values from 10 to 3. A high initial turbidity, adjusted by adding kaolin, adversely affected the efficiency of both systems and a decrease, about 15–25%; in inactivation of P. aeruginosa was observed. The kinetics of this study was investigated by Geeraerd Model for highlighting the best disinfection system based on reaction rate constant. The unique detailed investigation of P. aeruginosa disinfection with sunlight based disinfection systems under different weather conditions and variable parameters will help researchers to understand and further improve the newly invented SOCODIS system. PMID:24595188
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Heat inactivation of poliovirus in wastewater sludge
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ward, R.L.; Ashley, C.S.; Moseley, R.H.
1976-09-01
The effect of raw and anaerobically digested sludge on heat inactivation of poliovirus was investigated. Raw sludge was found to be very protective of poliovirus plaque-forming ability at all temperatures studied, but digested sludge had variable effects that were highly dependent upon the experimental conditions. In low concentrations and at relatively low inactivation temperatures, digested sludge is nearly as protective of poliovirus as raw sludge. However, at higher temperatures and concentrations, digested sludge caused a significant acceleration of poliovirus inactivation. The difference between the protective capability of raw and digested sludge is not due to loss of protective material, becausemore » this component is present in the solids of digested sludge as well as in those of raw sludge. Instead, the difference is due to a virucidal agent acquired during digestion. Addition of this agent to the solids of either raw or digested sludge reverses the protective potential of these solids during heat treatment of poliovirus.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Labatiuk, C.W.; Finch, G.R.; Belosevic, M.
1991-11-01
Giardia muris cyst viability after ozonation was compared by using fluorescein diacetate-ethidium bromide staining, the C3H/HeN mouse-G. muris model, and in vitro excystation. Bench-scale batch experiments were conducted under laboratory conditions (pH 6.7, 22C) in ozone-demand-free phosphate buffer. There was a significant difference between fluorogenic staining and infectivity with fluorogenic staining overestimating viability compared with infectivity estimates of viability. This suggests that viable cysts as indicated by fluorogenic dyes may not be able to complete the life cycle and produce an infection. No significant differences between infectivity and excystation and between fluorogenic staining and excystation were detected for inactivations upmore » to 99.9%. Only animal infectivity had the sensitivity to detect inactivations greater than 99.9%. Therefore, the animal model is the best method currently available for detecting high levels of G. muris cyst inactivation.« less
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Shen, Yun; Huang, Conghui; Lin, Jie; Wu, Wenjing; Ashbolt, Nicholas J; Liu, Wen-Tso; Nguyen, Thanh H
2017-02-21
Legionella pneumophila, the most commonly identified causative agent in drinking water associated with disease outbreaks, can be harbored by and released from drinking water biofilms. In this study, the release of biofilm-associated L. pneumophila under simulated drinking water flow containing a disinfectant residual was examined. Meanwhile, the inactivation and infectivity (to amoebae) of the released L. pneumophila were studied. To simulate drinking water system conditions, biofilms were prepared under either disinfectant exposure (predisinfected biofilms) or disinfectant-free (untreated biofilms) conditions, respectively. For experiments with water flow containing a disinfectant to release the biofilm-associated L. pneumophila from these two types of biofilms, the L. pneumophila release kinetics values from predisinfected and untreated biofilms under flow condition were not statistically different (one-way ANOVA, p > 0.05). However, inactivation of the L. pneumophila released from predisinfected biofilms was 1-2 times higher and amoeba infectivity was 2-29 times lower than that from untreated biofilms. The higher disinfectant resistance of L. pneumophila released from untreated biofilms was presumably influenced by the detachment of a larger amount of biofilm material (determined by 16S rRNA qPCR) surrounding the released L. pneumophila. This study highlights the interaction among disinfectant residual, biofilms, and L. pneumophila, which provides guidelines to assess and control pathogen risk.
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Kuhn, Brittany N; Klumpner, Marin S; Covelo, Ignacio R; Campus, Paolo; Flagel, Shelly B
2018-04-01
The paraventricular nucleus of the thalamus (PVT) has been shown to mediate cue-motivated behaviors, such as sign- and goal-tracking, as well as reinstatement of drug-seeking behavior. However, the role of the PVT in mediating individual variation in cue-induced drug-seeking behavior remains unknown. This study aimed to determine if inactivation of the PVT differentially mediates cue-induced drug-seeking behavior in sign-trackers and goal-trackers. Rats were characterized as sign-trackers (STs) or goal-trackers (GTs) based on their Pavlovian conditioned approach behavior. Rats were then exposed to 15 days of cocaine self-administration, followed by a 2-week forced abstinence period and then extinction training. Rats then underwent tests for cue-induced reinstatement and general locomotor activity, prior to which they received an infusion of either saline (control) or baclofen/muscimol (B/M) to inactivate the PVT. Relative to control animals of the same phenotype, GTs show a robust increase in cue-induced drug-seeking behavior following PVT inactivation, whereas the behavior of STs was not affected. PVT inactivation did not affect locomotor activity in either phenotype. In GTs, the PVT appears to inhibit the expression of drug-seeking, presumably by attenuating the incentive value of the drug cue. Thus, inactivation of the PVT releases this inhibition in GTs, resulting in an increase in cue-induced drug-seeking behavior. PVT inactivation did not affect cue-induced drug-seeking behavior in STs, suggesting that the role of the PVT in encoding the incentive motivational value of drug cues differs between STs and GTs.
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The effect of membrane composition on the hemostatic balance.
Smirnov, M D; Ford, D A; Esmon, C T; Esmon, N L
1999-03-23
The phospholipid composition requirements for optimal prothrombin activation and factor Va inactivation by activated protein C (APC) anticoagulant were examined. Vesicles composed of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) supported factor Va inactivation relatively well. However, optimal factor Va inactivation still required relatively high concentrations of phosphatidylserine (PS). In addition, at a fixed concentration of phospholipid, PS, and APC, vesicles devoid of PE never attained a rate of factor Va inactivation achievable with vesicles containing PE. Polyunsaturation of any vesicle component also contributed significantly to APC inactivation of factor Va. Thus, PE makes an important contribution to factor Va inactivation that cannot be mimicked by PS. In the absence of polyunsaturation in the other membrane constituents, this contribution was dependent upon the presence of both the PE headgroup per se and unsaturation of the 1,2 fatty acids. Although PE did not affect prothrombin activation rates at optimal PS concentrations, PE reduced the requirement for PS approximately 10-fold. The Km(app) for prothrombin and the Kd(app) for factor Xa-factor Va decreased as a function of increasing PS concentration, reaching optimal values at 10-15% PS in the absence of PE but only 1% PS in the presence of PE. Fatty acid polyunsaturation had minimal effects. A lupus anticoagulant immunoglobulin was more inhibitory to both prothrombinase and factor Va inactivation in the presence of PE. The degree of inhibition of APC was significantly greater and much more dependent on the phospholipid composition than that of prothrombinase. Thus, subtle changes in the phospholipid composition of cells may control procoagulant and anticoagulant reactions differentially under both normal and pathological conditions.
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Building Cre Knockin Rat Lines Using CRISPR/Cas9.
Ma, Yuanwu; Zhang, Lianfeng; Huang, Xingxu
2017-01-01
Conditional gene inactivation strategy helps researchers to study the gene functions that are critical in embryogenesis or in defined tissues of adulthood. The Cre/loxP system is widely used for conditional gene inactivation/activation in cells or organisms. Cre knockin animal lines are essential for gene expression or inactivation in a spatially and temporally restricted manner. However, to generate a Cre knockin line by traditional approach is laborious. Recently, the clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) has been proven as a simple and efficient genome-editing tool. We have used CRISPR/Cas9 system to generate rat strains that carry Cre genes in different targeted gene loci by direct delivery of gRNAs/Cas9/donors into fertilized eggs. Here, we described a stepwise procedure for the generation of Cre knockin rat, including target site selection, RNA preparation, the construction of the template donor, pronuclear injection, and the genotyping of precise Cre insertion in F 0 rats. Taken together, the establishment of Cre knockin line can be achieved within 6 weeks.
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Troyner, Fernanda; Bicca, Maira A; Bertoglio, Leandro J
2018-05-10
The thalamic nucleus reuniens (NR) has been shown to support bidirectional medial prefrontal cortex-hippocampus communication and synchronization relevant for cognitive processing. Using non-selective or prolonged inactivation of the NR, previous studies reported its activity positively modulates aversive memory consolidation. Here we examined the NR's role in consolidating contextual fear memories with varied strength, at both recent and more remote time points, using muscimol-induced temporary inactivation in rats. Results indicate the NR negatively modulates fear memory intensity, specificity and long-term maintenance. The more intense, generalized and enduring fear memory induced by NR inactivation during consolidation was also less prone to behavioral suppression by extinction or reconsolidation disruption induced by clonidine, an alpha-2 adrenergic receptor agonist. Lastly, we used immunohistochemistry for Arc protein, which is involved in synaptic modifications underlying aversive memory consolidation, to investigate whether treatment condition and/or conditioning status could change its levels in the NR, the hippocampus (dorsal and ventral CA1 subregions) and the medial prefrontal cortex (anterior cingulate, prelimbic and infralimbic subregions). Results indicate a significant imbalance in the number of Arc-expressing neurons in the brain areas investigated in muscimol fear conditioned animals when compared with controls. Collectively, present results provide convergent evidence for the NR's role as a hub regulating quantitative and qualitative aspects of a contextual fear memory during its consolidation that seem to influence the subsequent susceptibility to experimental interventions aiming at attenuating its expression. They also indicate the selectivity and duration of a given inactivation approach may influence its outcomes. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.
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Amaral, Larissa S; Azevedo, Eduardo B; Perussi, Janice R
2018-06-01
Antimicrobial Photodynamic Inactivation (a-PDI) is based on the oxidative destruction of biological molecules by reactive oxygen species generated by the photo-excitation of a photosensitive molecule. When a-PDT is performed with the use of mathematical models, the optimal conditions for maximum inactivation are found. Experimental designs allow a multivariate analysis of the experimental parameters. This is usually made using a univariate approach, which demands a large number of experiments, being time and money consuming. This paper presents the use of the response surface methodology for improving the search for the best conditions to reduce E. coli survival levels by a-PDT using methylene blue (MB) and toluidine blue (TB) as photosensitizers and white light. The goal was achieved by analyzing the effects and interactions of the three main parameters involved in the process: incubation time (IT), photosensitizer concentration (C PS ), and light dose (LD). The optimization procedure began with a full 2 3 factorial design, followed by a central composite one, in which the optimal conditions were estimated. For MB, C PS was the most important parameter followed by LD and IT whereas, for TB, the main parameter was LD followed by C PS and IT. Using the estimated optimal conditions for inactivation, MB was able to inactivate 99.999999% CFU mL -1 of E. coli with IT of 28 min, LD of 31 J cm -2 , and C PS of 32 μmol L -1 , while TB required 18 min, 39 J cm -2 , and 37 μmol L -1 . The feasibility of using the response surface methodology with a-PDT was demonstrated, enabling enhanced photoinactivation efficiency and fast results with a minimal number of experiments. Copyright © 2018 Elsevier B.V. All rights reserved.
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Jerking & confused: Leucine-rich glioma inactivated 1 receptor encephalitis.
Casault, Colin; Alikhani, Katayoun; Pillay, Neelan; Koch, Marcus
2015-12-15
This is a case of autoimmune encephalitis with features of faciobrachial dystonic seizures (FBDS) pathognomonic for Leucine Rich Glioma inactivated (LGI)1 antibody encephalitis. This voltage-gated potassium channel complex encephalitis is marked by rapid onset dementia, FBDS and hyponatremia, which is sensitive to management with immunotherapy including steroids, IVIG and other agents. In this case report we review the clinical features, imaging and management of this condition. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.
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THE EFFECT OF CHLORINE DEMAND ON INACTIVATION RATE CONSTANT
Ct (disinfectant concentration multiplied by exposure time) values are used by the US EPA to evaluate the efficacy of disinfection of microorganisms under various conditions of drinking water treatment conditions. First-order decay is usually assumed for the degradation of a disi...
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Noradrenaline and dopamine levels in acute cerveau isolé in the cat.
Szikszay, M; Benedek, G; Obál, F; Obál, F
1980-01-01
Noradrenaline (NA) and dopamine (DA) levels were studied in the forebrain of acute immobilized cats and in cerveau isolé preparations. A gradual decrease in NA and DA was observed one and two hours after high mesencephalic transection, while the amount of NA increased in acute immobilized cats after the cessation of ether anaesthesia. These changes in NA level are consistent with the observations suggesting an inverse relationship between NA and cortical deactivation. The decrease of DA with an exaggeration of spindle activity and increased synchronizing effect of basal forebrain stimulation indicate that the spindle-increasing effect of DA suggested by several authors requires the contribution of the brain stem.
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Ren, Chunli; Finkel, Steven E; Tower, John
2009-03-01
Immune function declines with age in Drosophila and humans, and autophagy is implicated in immune function. In addition, autophagy genes are required for life span extension caused by reduced insulin/IGF1-like signaling and dietary restriction in Caenorhabditiselegans. To test if the autophagy pathway might be limiting for immunity and/or life span in adult Drosophila, the Geneswitch system was used to cause conditional inactivation of the autophagy genes Atg5, Atg7 and Atg12 by RNAi. Conditional inhibition of Atg genes in adult flies reduced lysotracker staining of adult tissues, and reduced resistance to injected Escherichia coli, as evidenced by increased bacterial titers and reduced fly survival. However, survival of uninjected flies was unaffected by Atg gene inactivation. The data indicate that Atg gene activity is required for normal immune function in adult flies, and suggest that neither autophagy nor immune function are limiting for adult life span under typical laboratory conditions.
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Hossain, Md Sohrab; Nik Ab Rahman, Nik Norulaini; Balakrishnan, Venugopal; Alkarkhi, Abbas F M; Ahmad Rajion, Zainul; Ab Kadir, Mohd Omar
2015-04-01
Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO2) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and gram-negative Escherichia coli in CSW. The effects of SC-CO2 sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO2-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO2 exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Endothelial cell-derived GABA signaling modulates neuronal migration and postnatal behavior
Li, Suyan; Kumar T, Peeyush; Joshee, Sampada; Kirschstein, Timo; Subburaju, Sivan; Khalili, Jahan S; Kloepper, Jonas; Du, Chuang; Elkhal, Abdallah; Szabó, Gábor; Jain, Rakesh K; Köhling, Rüdiger; Vasudevan, Anju
2018-01-01
The cerebral cortex is essential for integration and processing of information that is required for most behaviors. The exquisitely precise laminar organization of the cerebral cortex arises during embryonic development when neurons migrate successively from ventricular zones to coalesce into specific cortical layers. While radial glia act as guide rails for projection neuron migration, pre-formed vascular networks provide support and guidance cues for GABAergic interneuron migration. This study provides novel conceptual and mechanistic insights into this paradigm of vascular-neuronal interactions, revealing new mechanisms of GABA and its receptor-mediated signaling via embryonic forebrain endothelial cells. With the use of two new endothelial cell specific conditional mouse models of the GABA pathway (Gabrb3ΔTie2-Cre and VgatΔTie2-Cre), we show that partial or complete loss of GABA release from endothelial cells during embryogenesis results in vascular defects and impairs long-distance migration and positioning of cortical interneurons. The downstream effects of perturbed endothelial cell-derived GABA signaling are critical, leading to lasting changes to cortical circuits and persistent behavioral deficits. Furthermore, we illustrate new mechanisms of activation of GABA signaling in forebrain endothelial cells that promotes their migration, angiogenesis and acquisition of blood-brain barrier properties. Our findings uncover and elucidate a novel endothelial GABA signaling pathway in the CNS that is distinct from the classical neuronal GABA signaling pathway and shed new light on the etiology and pathophysiology of neuropsychiatric diseases, such as autism spectrum disorders, epilepsy, anxiety, depression and schizophrenia. PMID:29086765
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Lipinski, Robert J; Holloway, Hunter T; O'Leary-Moore, Shonagh K; Ament, Jacob J; Pecevich, Stephen J; Cofer, Gary P; Budin, Francois; Everson, Joshua L; Johnson, G Allan; Sulik, Kathleen K
2014-01-01
Subtle behavioral and cognitive deficits have been documented in patient cohorts with orofacial clefts (OFCs). Recent neuroimaging studies argue that these traits are associated with structural brain abnormalities but have been limited to adolescent and adult populations where brain plasticity during infancy and childhood may be a confounding factor. Here, we employed high resolution magnetic resonance microscopy to examine primary brain morphology in a mouse model of OFCs. Transient in utero exposure to the Hedgehog (Hh) signaling pathway antagonist cyclopamine resulted in a spectrum of facial dysmorphology, including unilateral and bilateral cleft lip and palate, cleft of the secondary palate only, and a non-cleft phenotype marked by midfacial hypoplasia. Relative to controls, cyclopamine-exposed fetuses exhibited volumetric differences in several brain regions, including hypoplasia of the pituitary gland and olfactory bulbs, hyperplasia of the forebrain septal region, and expansion of the third ventricle. However, in affected fetuses the corpus callosum was intact and normal division of the forebrain was observed. This argues that temporally-specific Hh signaling perturbation can result in typical appearing OFCs in the absence of holoprosencephaly--a condition classically associated with Hh pathway inhibition and frequently co-occurring with OFCs. Supporting the premise that some forms of OFCs co-occur with subtle brain malformations, these results provide a possible ontological basis for traits identified in clinical populations. They also argue in favor of future investigations into genetic and/or environmental modulation of the Hh pathway in the etiopathogenesis of orofacial clefting.
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Gaidamakov, Sergei; Maximova, Olga A.; Chon, Hyongi; Blewett, Nathan H.; Wang, Hongsheng; Crawford, Amanda K.; Day, Amanda; Tulchin, Natalie; Crouch, Robert J.; Morse, Herbert C.; Blitzer, Robert D.
2014-01-01
La antigen (Sjögren's syndrome antigen B) is a phosphoprotein associated with nascent precursor tRNAs and other RNAs, and it is targeted by autoantibodies in patients with Sjögren's syndrome, systemic lupus erythematosus, and neonatal lupus. Increased levels of La are associated with leukemias and other cancers, and various viruses usurp La to promote their replication. Yeast cells (Saccharomyces cerevisiae and Schizosaccharomyces pombe) genetically depleted of La grow and proliferate, whereas deletion from mice causes early embryonic lethality, raising the question of whether La is required by mammalian cells generally or only to surpass a developmental stage. We developed a conditional La allele and used it in mice that express Cre recombinase in either B cell progenitors or the forebrain. B cell Mb1Cre La-deleted mice produce no B cells. Consistent with αCamKII Cre, which induces deletion in hippocampal CA1 cells in the third postnatal week and later throughout the neocortex, brains develop normally in La-deleted mice until ∼5 weeks and then lose a large amount of forebrain cells and mass, with evidence of altered pre-tRNA processing. The data indicate that La is required not only in proliferating cells but also in nondividing postmitotic cells. Thus, La is essential in different cell types and required for normal development of various tissue types. PMID:24190965
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Gaston-Massuet, Carles; McCabe, Mark J.; Scagliotti, Valeria; Young, Rodrigo M.; Carreno, Gabriela; Gregory, Louise C.; Jayakody, Sujatha A.; Pozzi, Sara; Gualtieri, Angelica; Basu, Basudha; Koniordou, Markela; Wu, Chun-I; Bancalari, Rodrigo E.; Rahikkala, Elisa; Veijola, Riitta; Lopponen, Tuija; Graziola, Federica; Turton, James; Signore, Massimo; Mousavy Gharavy, Seyedeh Neda; Charolidi, Nicoletta; Sokol, Sergei Y.; Merrill, Bradley J.; Dattani, Mehul T.; Martinez-Barbera, Juan Pedro
2016-01-01
Aberrant embryonic development of the hypothalamus and/or pituitary gland in humans results in congenital hypopituitarism (CH). Transcription factor 7-like 1 (TCF7L1), an important regulator of the WNT/β-catenin signaling pathway, is expressed in the developing forebrain and pituitary gland, but its role during hypothalamo–pituitary (HP) axis formation or involvement in human CH remains elusive. Using a conditional genetic approach in the mouse, we first demonstrate that TCF7L1 is required in the prospective hypothalamus to maintain normal expression of the hypothalamic signals involved in the induction and subsequent expansion of Rathke’s pouch progenitors. Next, we reveal that the function of TCF7L1 during HP axis development depends exclusively on the repressing activity of TCF7L1 and does not require its interaction with β-catenin. Finally, we report the identification of two independent missense variants in human TCF7L1, p.R92P and p.R400Q, in a cohort of patients with forebrain and/or pituitary defects. We demonstrate that these variants exhibit reduced repressing activity in vitro and in vivo relative to wild-type TCF7L1. Together, our data provide support for a conserved molecular function of TCF7L1 as a transcriptional repressor during HP axis development in mammals and identify variants in this transcription factor that are likely to contribute to the etiology of CH. PMID:26764381
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Raivio, Taneli; Avbelj, Magdalena; McCabe, Mark J.; Romero, Christopher J.; Dwyer, Andrew A.; Tommiska, Johanna; Sykiotis, Gerasimos P.; Gregory, Louise C.; Diaczok, Daniel; Tziaferi, Vaitsa; Elting, Mariet W.; Padidela, Raja; Plummer, Lacey; Martin, Cecilia; Feng, Bihua; Zhang, Chengkang; Zhou, Qun-Yong; Chen, Huaibin; Mohammadi, Moosa; Quinton, Richard; Sidis, Yisrael; Radovick, Sally; Dattani, Mehul T.
2012-01-01
Context: Kallmann syndrome (KS), combined pituitary hormone deficiency (CPHD), and septo-optic dysplasia (SOD) all result from development defects of the anterior midline in the human forebrain. Objective: The objective of the study was to investigate whether KS, CPHD, and SOD have shared genetic origins. Design and Participants: A total of 103 patients with either CPHD (n = 35) or SOD (n = 68) were investigated for mutations in genes implicated in the etiology of KS (FGFR1, FGF8, PROKR2, PROK2, and KAL1). Consequences of identified FGFR1, FGF8, and PROKR2 mutations were investigated in vitro. Results: Three patients with SOD had heterozygous mutations in FGFR1; these were either shown to alter receptor signaling (p.S450F, p.P483S) or predicted to affect splicing (c.336C>T, p.T112T). One patient had a synonymous change in FGF8 (c.216G>A, p.T72T) that was shown to affect splicing and ligand signaling activity. Four patients with CPHD/SOD were found to harbor heterozygous rare loss-of-function variants in PROKR2 (p.R85G, p.R85H, p.R268C). Conclusions: Mutations in FGFR1/FGF8/PROKR2 contributed to 7.8% of our patients with CPHD/SOD. These data suggest a significant genetic overlap between conditions affecting the development of anterior midline in the human forebrain. PMID:22319038
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Sajedi, Ezat; Gaston-Massuet, Carles; Signore, Massimo; Andoniadou, Cynthia L.; Kelberman, Daniel; Castro, Sandra; Etchevers, Heather C.; Gerrelli, Dianne; Dattani, Mehul T.; Martinez-Barbera, Juan Pedro
2008-01-01
SUMMARY A homozygous substitution of the highly conserved isoleucine at position 26 by threonine (I26T) in the transcriptional repressor HESX1 has been associated with anterior pituitary hypoplasia in a human patient, with no forebrain or eye defects. Two individuals carrying a homozygous substitution of the conserved arginine at position 160 by cysteine (R160C) manifest septo-optic dysplasia (SOD), a condition characterised by pituitary abnormalities associated with midline telencephalic structure defects and optic nerve hypoplasia. We have generated two knock-in mouse models containing either the I26T or R160C substitution in the genomic locus. Hesx1I26T/I26T embryos show pituitary defects comparable with Hesx1−/− mouse mutants, with frequent occurrence of ocular abnormalities, although the telencephalon develops normally. Hesx1R160C/R160C mutants display forebrain and pituitary defects that are identical to those observed in Hesx1−/− null mice. We also show that the expression pattern of HESX1 during early human development is very similar to that described in the mouse, suggesting that the function of HESX1 is conserved between the two species. Together, these results suggest that the I26T mutation yields a hypomorphic allele, whereas R160C produces a null allele and, consequently, a more severe phenotype in both mice and humans. PMID:19093031
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Scully, Erin N; Hahn, Allison H; Campbell, Kimberley A; McMillan, Neil; Congdon, Jenna V; Sturdy, Christopher B
2017-07-28
Zebra finches (Taeniopygia guttata) are sexually dimorphic songbirds, not only in appearance but also in vocal production: while males produce both calls and songs, females only produce calls. This dimorphism provides a means to contrast the auditory perception of vocalizations produced by songbird species of varying degrees of relatedness in a dimorphic species to that of a monomorphic species, species in which both males and females produce calls and songs (e.g., black-capped chickadees, Poecile atricapillus). In the current study, we examined neuronal expression after playback of acoustically similar hetero- and conspecific calls produced by species of differing phylogenetic relatedness to our subject species, zebra finch. We measured the immediate early gene (IEG) ZENK in two auditory areas of the forebrain (caudomedial mesopallium, CMM, and caudomedial nidopallium, NCM). We found no significant differences in ZENK expression in either male or female zebra finches regardless of playback condition. We also discuss comparisons between our results and the results of a previous study conducted by Avey et al. [1] on black-capped chickadees that used similar stimulus types. These results are consistent with the previous study which also found no significant differences in expression following playback of calls produced by various heterospecific species and conspecifics [1]. Our results suggest that, similar to black-capped chickadees, IEG expression in zebra finch CMM and NCM is tied to the acoustic similarity of vocalizations and not the phylogenetic relatedness of the species producing the vocalizations. Copyright © 2017 Elsevier B.V. All rights reserved.
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Chlorine decay and bacterial inactivation kinetics in drinking water in the tropics.
Thøgersen, J; Dahi, E
1996-09-01
The decay of free chlorine (Cl2) and combined chlorine (mostly monochloramine: NH2Cl) and the inactivation of bacteria was examined in Dar es Salaam, Tanzania. Batch experiments, pilot-scale pipe experiments and full-scale pipe experiments were carried out to establish the kinetics for both decay and inactivation, and to compare the two disinfectants for use under tropical conditions. The decay of both disinfectants closely followed first order kinetics, with respect to the concentration of both disinfectant and disinfectant-consuming substances. Bacterial densities exhibited a kinetic pattern consisting of first order inactivation with respect to the density of the bacteria and the concentration of the disinfectant, and first order growth with respect to the bacterial density. The disinfection kinetic model takes the decaying concentration of the disinfectant into account. The decay rate constant for free chlorine was 114 lg(-1)h(-1), while the decay rate constant for combined chlorine was 1.84 lg(-1)h(-1) (1.6% of the decay rate for free chlorine). The average concentration of disinfectant consuming substances in the water phase was 2.6 mg Cl2/l for free chlorine and 5.6 mg NH2Cl/l for combined chlorine. The decay rate constant and the concentration of disinfectant consuming substances when water was pumped through pipes, depended on whether or not chlorination was continuous. Combined chlorine especially could clean the pipes of disinfectant consuming substances. The inactivation rate constant λ, was estimated at 3.06×10(4) lg(-1)h(-1). Based on the inactivation rate constant, and a growth rate constant determined in a previous study, the critical concentration of free chlorine was found to be 0.08 mg Cl2/l. The critical concentration is a value below which growth rates dominate over inactivation.
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Yousefzadeh, Samira; Matin, Atiyeh Rajabi; Ahmadi, Ehsan; Sabeti, Zahra; Alimohammadi, Mahmood; Aslani, Hassan; Nabizadeh, Ramin
2018-04-01
One of the most important aspects of environmental issues is the demand for clean and safe water. Meanwhile, disinfection process is one of the most important steps in safe water production. The present study aims at estimating the performance of UV, nano Zero-Valent Iron particles (nZVI, nano-Fe 0 ), and UV treatment with the addition of nZVI (combined process) for Bacillus subtilis spores inactivation. Effects of different factors on inactivation including contact time, initial nZVI concentration, UV irradiance and various aerations conditions were investigated. Response surface methodology, based on a five-level, two variable central composite design, was used to optimize target microorganism reduction and the experimental parameters. The results indicated that the disinfection time had the greatest positive impact on disinfection ability among the different selected independent variables. According to the results, it can be concluded that microbial reduction by UV alone was more effective than nZVI while the combined UV/nZVI process demonstrated the maximum log reduction. The optimum reduction of about 4 logs was observed at 491 mg/L of nZVI and 60 min of contact time when spores were exposed to UV radiation under deaerated condition. Therefore, UV/nZVI process can be suggested as a reliable method for Bacillus subtilis spores inactivation. Copyright © 2018. Published by Elsevier Ltd.
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Hakim, Hakimullah; Thammakarn, Chanathip; Suguro, Atsushi; Ishida, Yuki; Kawamura, Akinobu; Tamura, Miho; Satoh, Keisuke; Tsujimura, Misato; Hasegawa, Tomomi; Takehara, Kazuaki
2015-02-01
Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5% fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5% FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying, while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level.
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Du, Suping; Zhang, Zhaohuan; Xiao, Lili; Lou, Yang; Pan, Yingjie; Zhao, Yong
2016-01-01
Acidic electrolyzed water (AEW), a novel non-thermal sterilization technology, is widely used in the food industry. In this study, we firstly investigated the effect of AEW as a new pressure transmitting medium for high hydrostatic pressure (AEW-HHP) processing on microorganisms inactivation on shelled fresh shrimp. The optimal conditions of AEW-HHP for Vibrio parahaemolyticus inactivation on sterile shelled fresh shrimp were obtained using response surface methodology: NaCl concentration to electrolysis 1.5 g/L, treatment pressure 400 MPa, treatment time 10 min. Under the optimal conditions mentioned above, AEW dramatically enhanced the efficiency of HHP for inactivating V. parahaemolyticus and Listeria monocytogenes on artificially contaminated shelled fresh shrimp, and the log reductions were up to 6.08 and 5.71 log10 CFU/g respectively, while the common HHP could only inactivate the two pathogens up to 4.74 and 4.31 log10 CFU/g respectively. Meanwhile, scanning electron microscopy (SEM) showed the same phenomenon. For the naturally contaminated shelled fresh shrimp, AEW-HHP could also significantly reduce the micro flora when examined using plate count and PCR-DGGE. There were also no significant changes, histologically, in the muscle tissues of shrimps undergoing the AEW-HHP treatment. In summary, using AEW as a new transmitting medium for HHP processing is an innovative non thermal technology for improving the food safety of shrimp and other aquatic products. PMID:27014228
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Lee, Hye-Jin; Kim, Hyung-Eun; Lee, Changha
2017-03-01
Combinations of Cu(II) with hydroxylamine (HA) and hydrogen peroxide (H 2 O 2 ) (i.e., Cu(II)/HA, Cu(II)/H 2 O 2 , and Cu(II)/HA/H 2 O 2 systems) were investigated for the control of P. aeruginosa biofilms on reverse osmosis (RO) membranes. These Cu(II)-based disinfection systems effectively inactivated P. aeruginosa cells, exhibiting different behaviors depending on the state of bacterial cells (planktonic or biofilm) and the condition of biofilm growth and treatment (normal or pressurized condition). The Cu(II)/HA and Cu(II)/HA/H 2 O 2 systems were the most effective reagents for the inactivation of planktonic cells. However, these systems were not effective in inactivating cells in biofilms on the RO membranes possibly due to the interactions of Cu(I) with extracellular polymeric substances (EPS), where biofilms were grown and treated in center for disease control (CDC) reactors. Different from the results using CDC reactors, in a pressurized cross-flow RO filtration unit, the Cu(II)/HA/H 2 O 2 treatment significantly inactivated biofilm cells formed on the RO membranes, successfully recovering the permeate flux reduced by the biofouling. The pretreatment of feed solutions by Cu(II)/HA and Cu(II)/HA/H 2 O 2 systems (applied before the biofilm formation) effectively mitigated the permeate flux decline by preventing the biofilm growth on the RO membranes. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Surendran, Kameswaran; Boyle, Scott; Barak, Hila; Kim, Mijin; Stromberski, Colin; McCright, Brent; Kopan, Raphael
2009-01-01
We previously determined that Notch2, and not Notch1 was required for forming proximal nephron segments. The dominance of Notch2 may be conserved in humans, since Notch2 mutations occur in Alagille syndrome (ALGS) 2 patients, which includes renal complications. To test whether mutations in Notch1 could increase the severity of renal complications in ALGS, we inactivated conditional Notch1 and Notch2 alleles in mice using a Six2-GFP∷Cre. This BAC transgene is expressed mosaically in renal epithelial progenitors but uniformly in cells exiting the progenitor pool to undergo mesenchymal to epithelial transition. Although delaying Notch2 inactivation had a marginal effect on nephron numbers, it created a sensitized background in which the inactivation of Notch1 severely compromised nephron formation, function and survival. These and additional observations indicate that Notch1 in concert with Notch2 contributes to the morphogenesis of renal vesicles into S-shaped bodies in a RBP-J dependent manner. A significant implication is that elevating Notch1 activity could improve renal functions in ALGS2 patients. As proof of principle, we determined that conditional inactivation of Mint, an inhibitor of Notch-RBP-J interaction, resulted in a moderate rescue of Notch2 null kidneys, implying that temporal blockage of Notch signaling inhibitors downstream of receptor activation may have therapeutic benefits for ALGS patients. PMID:19914235
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Roybal, Paul G.; Wu, Nancy L.; Sun, Jingjing; Ting, Man-chun; Schaefer, Christopher; Maxson, Robert E.
2011-01-01
In an effort to understand the morphogenetic forces that shape the bones of the skull, we inactivated Msx1 and Msx2 conditionally in neural crest. We show that Wnt1-Cre inactivation of up to three Msx1/2 alleles results in a progressively larger defect in the neural crest-derived frontal bone. Unexpectedly, in embryos lacking all four Msx1/2 alleles, the large defect is filled in with mispatterned bone consisting of ectopic islands of bone between the reduced frontal bones, just anterior to the parietal bones. The bone is derived from neural crest, not mesoderm, and, from DiI cell marking experiments, originates in a normally non-osteogenic layer of cells through which the rudiment elongates apically. Associated with the heterotopic osteogeneis is an upregulation of Bmp signaling in this cell layer. Prevention of this upregulation by implantation of noggin-soaked beads in head explants also prevented heterotopic bone formation. These results suggest that Msx genes have a dual role in calvarial development: They are required for the differentiation and proliferation of osteogenic cells within rudiments, and they are also required to suppress an osteogenic program in a cell layer within which the rudiments grow. We suggest that the inactivation of this repressive activity may be one cause of Wormian bones, ectopic bones that are a feature of a variety of pathological conditions in which calvarial bone development is compromised. PMID:20398647
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Xiong, Mengneng; Zhu, Zhiping; Tian, Suwen; Zhu, Ruping; Bai, Shun; Fu, Kaiqiang; Davis, James G; Sun, Zheng; Baur, Joseph A; Zheng, Ke; Ye, Lan
2017-09-01
Rapamycin is a clinically important drug that is used in transplantation and cancer therapy but which causes a number of side effects, including male infertility. Its canonical target, mammalian target of rapamycin complex 1 (mTORC1), plays a key role in metabolism and binds chromatin; however, its precise role in the male germline has not been elucidated. Here, we inactivate the core component, Raptor, to show that mTORC1 function is critical for male meiosis and the inactivation of sex chromosomes. Disruption of the Raptor gene impairs chromosomal synapsis and prevents the efficient spreading of silencing factors into the XY chromatin. Accordingly, mRNA for XY-linked genes remains inappropriately expressed in Raptor -deficient mice. Molecularly, the failure to suppress gene expression corresponded with deficiencies in 2 repressive chromatin markers, H3K9 dimethylation and H3K9 trimethylation, in the XY body. Together, these results demonstrate that mTORC1 has an essential role in the meiotic progression and silencing of sex chromosomes in the male germline, which may explain the infertility that has been associated with such inhibitors as rapamycin.-Xiong, M., Zhu, Z., Tian, S., Zhu, R., Bai, S., Fu, K., Davis, J. G., Sun, Z., Baur, J. A., Zheng, K., Ye, L. Conditional ablation of Raptor in the male germline causes infertility due to meiotic arrest and impaired inactivation of sex chromosomes. © FASEB.
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West Nile virus in plasma is highly sensitive to methylene blue-light treatment.
Mohr, Harald; Knüver-Hopf, Joseph; Gravemann, Ute; Redecker-Klein, Anette; Müller, Thomas H
2004-06-01
The epidemic of West Nile virus (WNV) in the US resulted in cases of transfusion-transmitted WNV. Effective pathogen reduction methods could have removed this infectious agent from the blood supply We have evaluated the efficacy of photodynamic treatment of fresh frozen plasma (FFP) with methylene blue (MB), a decontamination method applied in several European countries. FFP units (300 ml each) were spiked with WNV. MB was added, and the units were illuminated with white or monochromatic yellow light. WNV infectivity was determined by bioassay. WNV-RNA was quantitated by real-time PCR. The inactivation of WNV was investigated under standard and under suboptimal conditions, respectively. In addition, rechallenge experiments with multiple addition of WNV at maximal load (approx. 105 CFU/ml) and repeated illumination without replenishing MB were performed. Complete inactivation of WNV was achieved by MB (0.8-1 mmol/l) and illumination with white light (30,000-45,000 Lux) within 2 min. White yellow light 20-40 J/cm(2) (2.5-5 min) were sufficient for inactivation by 5.75 log10-steps. The rechallenge experiments revealed the substantial reserve capacity of the procedure to inactivate WNV. Quantitative PCR indicated that the viral RNA was rapidly destroyed. All experimental data demonstrate the enormous potency of phototreatment with MB to inactivate WNV in plasma.
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Thermal inactivation of alkali phosphatases under various conditions
NASA Astrophysics Data System (ADS)
Atyaksheva, L. F.; Tarasevich, B. N.; Chukhrai, E. S.; Poltorak, O. M.
2009-02-01
The thermal inactivation of alkali phosphatases from bacteria Escherichia coli (ECAP), bovine intestines (bovine IAP), and chicken intestines (chicken IAP) was studied in different buffer solutions and in the solid state. The conclusion was made that these enzymes had maximum stability in the solid state, and, in a carbonate buffer solution, their activity decreased most rapidly. It was found that the bacterial enzyme was more stable than animal phosphatases. It was noted that, for ECAP, four intermediate stages preceded the loss of enzyme activity, and, for bovine and chicken IAPs, three intermediate stages were observed. The activation energy of thermal inactivation of ECAP over the range 25-70°C was determined to be 80 kJ/mol; it corresponded to the dissociation of active dimers into inactive monomers. Higher activation energies (˜200 kJ/mol) observed at the initial stage of thermal inactivation of animal phosphatases resulted from the simultaneous loss of enzyme activity caused by dimer dissociation and denaturation. It was shown that the activation energy of denaturation of monomeric animal alkali phosphatases ranged from 330 to 380 kJ/mol depending on buffer media. It was concluded that the inactivation of solid samples of alkali phosphatases at 95°C was accompanied by an about twofold decrease in the content of β structures in protein molecules.
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Disinfection of Ebola Virus in Sterilized Municipal Wastewater
Fischer, Robert J.; Casson, Leonard W.; de Carvalho, Nathalia Aquino; Haas, Charles N.; Munster, Vincent J.
2017-01-01
Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit) following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids) will require additional verification. PMID:28146555
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Disinfection of Ebola Virus in Sterilized Municipal Wastewater.
Bibby, Kyle; Fischer, Robert J; Casson, Leonard W; de Carvalho, Nathalia Aquino; Haas, Charles N; Munster, Vincent J
2017-02-01
Concerns have been raised regarding handling of Ebola virus contaminated wastewater, as well as the adequacy of proposed disinfection approaches. In the current study, we investigate the inactivation of Ebola virus in sterilized domestic wastewater utilizing sodium hypochlorite addition and pH adjustment. No viral inactivation was observed in the one-hour tests without sodium hypochlorite addition or pH adjustment. No virus was recovered after 20 seconds (i.e. 4.2 log10 unit inactivation to detection limit) following the addition of 5 and 10 mg L-1 sodium hypochlorite, which resulted in immediate free chlorine residuals of 0.52 and 1.11 mg L-1, respectively. The addition of 1 mg L-1 sodium hypochlorite resulted in an immediate free chlorine residual of 0.16 mg L-1, which inactivated 3.5 log10 units of Ebola virus in 20 seconds. Further inactivation was not evident due to the rapid consumption of the chlorine residual. Elevating the pH to 11.2 was found to significantly increase viral decay over ambient conditions. These results indicate the high susceptibility of the enveloped Ebola virus to disinfection in the presence of free chlorine in municipal wastewater; however, we caution that extension to more complex matrices (e.g. bodily fluids) will require additional verification.
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Agcam, E; Akyıldız, A; Evrendilek, G Akdemir
2014-12-15
The inactivation kinetics of pectin methyl esterase (PME) during the shelf life (4°C-180 days) of freshly squeezed orange juice samples processed by both pulsed electric fields (PEF) and heat pasteurization (HP) was evaluated in the study. The PME inactivation level after the PEF (25.26 kV/cm-1206.2 μs) and HP (90°C-20s) treatments were 93.8% and 95.2%, respectively. The PME activity of PEF-processed samples decreased or did not change, while that of HP samples increased during storage (p<0.01). A kinetic model was developed expressing PME inactivation as a function of the PEF treatment conditions, and this enabled the estimation of the reaction rate constant (587.8-2375.4s(-1)), and the time required for a 90% reduction (De, 3917.7-969.5s). Quantification of the increase in PEF energy to ensure a ten-fold reduction in De (ze, 63.7 J), activation electric fields (-921.2 kV cm(-1)mol(-1)), and electrical activation energy (12.9 kJ mol(-1)) was also carried out. Consequently, PEF processing was very effective for the inactivation of PME and for providing stability of orange juice during storage. Copyright © 2014. Published by Elsevier Ltd.
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Two Components of Voltage-Dependent Inactivation in Cav1.2 Channels Revealed by Its Gating Currents
Ferreira, Gonzalo; Ríos, Eduardo; Reyes, Nicolás
2003-01-01
Voltage-dependent inactivation (VDI) was studied through its effects on the voltage sensor in Cav1.2 channels expressed in tsA 201 cells. Two kinetically distinct phases of VDI in onset and recovery suggest the presence of dual VDI processes. Upon increasing duration of conditioning depolarizations, the half-distribution potential (V1/2) of intramembranous mobile charge was negatively shifted as a sum of two exponential terms, with time constants 0.5 s and 4 s, and relative amplitudes near 50% each. This kinetics behavior was consistent with that of increment of maximal charge related to inactivation (Qn). Recovery from inactivation was also accompanied by a reduction of Qn that varied with recovery time as a sum of two exponentials. The amplitudes of corresponding exponential terms were strongly correlated in onset and recovery, indicating that channels recover rapidly from fast VDI and slowly from slow VDI. Similar to charge “immobilization,” the charge moved in the repolarization (OFF) transient became slower during onset of fast VDI. Slow VDI had, instead, hallmarks of interconversion of charge. Confirming the mechanistic duality, fast VDI virtually disappeared when Li+ carried the current. A nine-state model with parallel fast and slow inactivation pathways from the open state reproduces most of the observations. PMID:12770874
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Baysal, Ayse Handan; Molva, Celenk; Unluturk, Sevcan
2013-09-16
In the present study, the effect of short wave ultraviolet light (UV-C) on the inactivation of Alicyclobacillus acidoterrestris DSM 3922 spores in commercial pasteurized white grape and apple juices was investigated. The inactivation of A. acidoterrestris spores in juices was examined by evaluating the effects of UV light intensity (1.31, 0.71 and 0.38 mW/cm²) and exposure time (0, 3, 5, 7, 10, 12 and 15 min) at constant depth (0.15 cm). The best reduction (5.5-log) was achieved in grape juice when the UV intensity was 1.31 mW/cm². The maximum inactivation was approximately 2-log CFU/mL in apple juice under the same conditions. The results showed that first-order kinetics were not suitable for the estimation of spore inactivation in grape juice treated with UV-light. Since tailing was observed in the survival curves, the log-linear plus tail and Weibull models were compared. The results showed that the log-linear plus tail model was satisfactorily fitted to estimate the reductions. As a non-thermal technology, UV-C treatment could be an alternative to thermal treatment for grape juices or combined with other preservation methods for the pasteurization of apple juice. © 2013 Elsevier B.V. All rights reserved.
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Huang, Runze; Li, Xinhui; Huang, Yaoxin; Chen, Haiqiang
2014-08-18
Due to the increasing concern of viral infection related to berries, this study investigated strategies to enhance high hydrostatic pressure (HHP) inactivation of murine norovirus 1 (MNV-1), a human norovirus (HuNoV) surrogate, on strawberries and in strawberry puree. Strawberry puree was inoculated with ~10(6)PFU/g of MNV-1 and treated at 350 MPa for 2 min at initial sample temperatures of 0, 5, 10 and 20°C. MNV-1 became more sensitive to HHP as initial sample temperature decreased from 20 to 0°C. To determine the effect of pressure cycling on MNV-1 inactivation, inoculated puree samples were treated at 300 MPa and 0°C with 1, 2 and 4 cycles. Pressure cycling offered no distinct advantage over continuous HHP treatment. To determine the effect of presence of water during HHP on MNV-1 inactivation, strawberries inoculated with ~ 4 × 10(5)PFU/g of MNV-1 were either pressure-treated directly (dry state) or immersed in water during pressure treatment. MNV-1 was very resistant to pressure under the dry state condition, but became sensitive to pressure under the wet state condition. The inactivation curves of MNV-1 in strawberry puree and on strawberries were obtained at 300 and 350 MPa and initial sample temperature of 0°C. Except for the curve of strawberries treated at 350 MPa which had a concave downward shape, the other three curves were almost linear with R(2) value of 0.99. The fate of MNV-1 in the un-treated and pressure-treated strawberries and strawberry puree during frozen storage was determined. The virus was relatively stable and only reduced by <1.2 log during the 28-day frozen storage. In all, this study provides practical insights of designing strategies using HHP to inactivate HuNoV on strawberries and in strawberry puree assuming that HuNoV behaved similarly to MNV-1 when treated by HHP. Copyright © 2014 Elsevier B.V. All rights reserved.
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Marcelino, Isabel; Lefrançois, Thierry; Martinez, Dominique; Giraud-Girard, Ken; Aprelon, Rosalie; Mandonnet, Nathalie; Gaucheron, Jérôme; Bertrand, François; Vachiéry, Nathalie
2015-01-29
The use of cheap and thermoresistant vaccines in poor tropical countries for the control of animal diseases is a key issue. Our work aimed at designing and validating a process for the large-scale production of a ready-to-use inactivated vaccine for ruminants. Our model was heartwater caused by the obligate intracellular bacterium Ehrlichia ruminantium (ER). The conventional inactivated vaccine against heartwater (based on whole bacteria inactivated with sodium azide) is prepared immediately before injection, using a syringe-extrusion method with Montanide ISA50. This is a fastidious time-consuming process and it limits the number of vaccine doses available. To overcome these issues, we tested three different techniques (syringe, vortex and homogenizer) and three Montanide ISA adjuvants (50, 70 and 70M). High-speed homogenizer was the optimal method to emulsify ER antigens with both ISA70 and 70M adjuvants. The emulsions displayed a good homogeneity (particle size below 1 μm and low phase separation), conductivity below 10 μS/cm and low antigen degradation at 4 °C for up to 1 year. The efficacy of the different formulations was then evaluated during vaccination trials on goats. The inactivated ER antigens emulsified with ISA70 and ISA70M in a homogenizer resulted in 80% and 100% survival rates, respectively. A cold-chain rupture assay using ISA70M+ER was performed to mimic possible field conditions exposing the vaccine at 37 °C for 4 days before delivery. Surprisingly, the animal survival rate was still high (80%). We also observed that the MAP-1B antibody response was very similar between animals vaccinated with ISA70+ER and ISA70M+ER emulsions, suggesting a more homogenous antigen distribution and presentation in these emulsions. Our work demonstrated that the combination of ISA70 or ISA70M and homogenizer is optimal for the production of an effective ready-to-use inactivated vaccine against heartwater, which could easily be produced on an industrial scale. Copyright © 2014 Elsevier Ltd. All rights reserved.
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ERIC Educational Resources Information Center
Markham, Chris M.; Taylor, Stacie L.; Huhman, Kim L.
2010-01-01
We examined the roles of the amygdala and hippocampus in the formation of emotionally relevant memories using an ethological model of conditioned fear termed conditioned defeat (CD). Temporary inactivation of the ventral, but not dorsal hippocampus (VH, DH, respectively) using muscimol disrupted the acquisition of CD, whereas pretraining VH…
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Inactivation of Escherichia coli in milk and concentrated milk using pulsed-light treatment.
Miller, B M; Sauer, A; Moraru, C I
2012-10-01
Pulsed light (PL) treatment has been viewed as an alternative to thermal treatments for the inactivation of pathogenic and spoilage microorganisms in recent years. The objectives of this study were to quantify the effectiveness of PL on inactivating Escherichia coli in cow milk and to evaluate the effect of total solids and fat content on inactivation. Samples of reconstituted milk with variable total solids levels (9.8, 25, and 45%) and commercial cow milk with different fat contents (skim milk, 2% fat, and whole milk) were inoculated with nonpathogenic E. coli ATCC 25922 at a concentration of 10(7)cfu/mL. One milliliter of the inoculated sample was placed in a thin layer in a glass chamber and exposed to PL doses of up to 14.9 J/cm(2), both in static mode and turbulent mode. Survivors were quantified using standard plate counting. All experiments were performed in triplicate. Pulsed light treatment of the concentrated milks of 25 and 45% solids content resulted in reductions of less than 1 log, even in turbulent mode, whereas for the milk with 9.8% solids content, reduction levels of 2.5 log cfu were obtained after treatment with 8.4 J/cm(2) in turbulent mode. In the skim milk, a 3.4 log cfu reduction at 14.9 J/cm(2) was obtained and a plateau of the inactivation curve typical of PL treatment was not achieved. Under the same conditions, both 2% and whole milk attained inactivation levels greater than 2.5 log cfu. These data indicate that PL is effective for the inactivation of E. coli in milk, but has limited effectiveness for microbial inactivation in concentrated milk, due to the absorption of light by the milk solids and shielding of the bacteria in the concentrated substrates. Milk fat also diminishes the effectiveness of PL to some extent, due to light-scattering effects. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
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Riungu, Joy; Ronteltap, Mariska; van Lier, Jules B
2018-06-01
This study examined the potential of Escherichia coli (E. coli) and Ascaris lumbricoides (A. lumbricoides) eggs inactivation in faecal matter coming from urine diverting dehydrating toilets (UDDT-F) by applying high concentrations of volatile fatty acids (VFAs) during anaerobic stabilization. The impact of individual VFAs on E. coli and A. lumbricoides eggs inactivation in UDDT-F was assessed by applying various concentrations of store-bought acetate, propionate and butyrate. High VFA concentrations were also obtained by performing co-digestion of UDDT-F with organic market waste (OMW) using various mixing ratios. All experiments were performed under anaerobic conditions in laboratory scale batch assays at 35±1 °C. A correlation was observed between E. coli log inactivation and VFA concentration. Store bought VFA spiked UDDT-F substrates achieved E. coli inactivation up to 4.7 log units/day compared to UDDT-F control sample that achieved 0.6 log units/day. In co-digesting UDDT-F and organic market waste (OMW), a ND-VFA concentration of 4800-6000 mg/L was needed to achieve E. coli log inactivation to below detectable levels and complete A. lumbricoides egg inactivation in less than four days. E. coli and A. lumbricoides egg inactivation was found to be related to the concentration of non-dissociated VFA (ND-VFA), increasing with an increase in the OMW fraction in the feed substrate. Highest ND-VFA concentration of 6500 mg/L was obtained at a UDDT-F:OMW ratio 1:1, below which there was a decline, attributed to product inhibition of acidogenic bacteria. Results of our present research showed the potential for E. coli and A. lumbricoides inactivation from UDDT-F up to WHO standards by allowing VFA build-up during anaerobic stabilization of faecal matter. Copyright © 2018. Published by Elsevier Ltd.
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Amarillo, Yimy; De Santiago-Castillo, Jose A; Dougherty, Kevin; Maffie, Jonathon; Kwon, Elaine; Covarrubias, Manuel; Rudy, Bernardo
2008-04-15
Kv4 channels mediate most of the somatodendritic subthreshold operating A-type current (I(SA)) in neurons. This current plays essential roles in the regulation of spike timing, repetitive firing, dendritic integration and plasticity. Neuronal Kv4 channels are thought to be ternary complexes of Kv4 pore-forming subunits and two types of accessory proteins, Kv channel interacting proteins (KChIPs) and the dipeptidyl-peptidase-like proteins (DPPLs) DPPX (DPP6) and DPP10. In heterologous cells, ternary Kv4 channels exhibit inactivation that slows down with increasing depolarization. Here, we compared the voltage dependence of the inactivation rate of channels expressed in heterologous mammalian cells by Kv4.2 proteins with that of channels containing Kv4.2 and KChIP1, Kv4.2 and DPPX-S, or Kv4.2, KChIP1 and DPPX-S, and found that the relation between inactivation rate and membrane potential is distinct for these four conditions. Moreover, recordings from native neurons showed that the inactivation kinetics of the I(SA) in cerebellar granule neurons has voltage dependence that is remarkably similar to that of ternary Kv4 channels containing KChIP1 and DPPX-S proteins in heterologous cells. The fact that this complex and unique behaviour (among A-type K(+) currents) is observed in both the native current and the current expressed in heterologous cells by the ternary complex containing Kv4, DPPX and KChIP proteins supports the hypothesis that somatically recorded native Kv4 channels in neurons include both types of accessory protein. Furthermore, quantitative global kinetic modelling showed that preferential closed-state inactivation and a weakly voltage-dependent opening step can explain the slowing of the inactivation rate with increasing depolarization. Therefore, it is likely that preferential closed-state inactivation is the physiological mechanism that regulates the activity of both ternary Kv4 channel complexes and native I(SA)-mediating channels.
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Zebrafish zic2 controls formation of periocular neural crest and choroid fissure morphogenesis.
Sedykh, Irina; Yoon, Baul; Roberson, Laura; Moskvin, Oleg; Dewey, Colin N; Grinblat, Yevgenya
2017-09-01
The vertebrate retina develops in close proximity to the forebrain and neural crest-derived cartilages of the face and jaw. Coloboma, a congenital eye malformation, is associated with aberrant forebrain development (holoprosencephaly) and with craniofacial defects (frontonasal dysplasia) in humans, suggesting a critical role for cross-lineage interactions during retinal morphogenesis. ZIC2, a zinc-finger transcription factor, is linked to human holoprosencephaly. We have previously used morpholino assays to show zebrafish zic2 functions in the developing forebrain, retina and craniofacial cartilage. We now report that zebrafish with genetic lesions in zebrafish zic2 orthologs, zic2a and zic2b, develop with retinal coloboma and craniofacial anomalies. We demonstrate a requirement for zic2 in restricting pax2a expression and show evidence that zic2 function limits Hh signaling. RNA-seq transcriptome analysis identified an early requirement for zic2 in periocular neural crest as an activator of alx1, a transcription factor with essential roles in craniofacial and ocular morphogenesis in human and zebrafish. Collectively, these data establish zic2 mutant zebrafish as a powerful new genetic model for in-depth dissection of cell interactions and genetic controls during craniofacial complex development. Copyright © 2017 Elsevier Inc. All rights reserved.
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Loss of MeCP2 From Forebrain Excitatory Neurons Leads to Cortical Hyperexcitation and Seizures
Zhang, Wen; Peterson, Matthew; Beyer, Barbara; Frankel, Wayne N.
2014-01-01
Mutations of MECP2 cause Rett syndrome (RTT), a neurodevelopmental disorder leading to loss of motor and cognitive functions, impaired social interactions, and seizure at young ages. Defects of neuronal circuit development and function are thought to be responsible for the symptoms of RTT. The majority of RTT patients show recurrent seizures, indicating that neuronal hyperexcitation is a common feature of RTT. However, mechanisms underlying hyperexcitation in RTT are poorly understood. Here we show that deletion of Mecp2 from cortical excitatory neurons but not forebrain inhibitory neurons in the mouse leads to spontaneous seizures. Selective deletion of Mecp2 from excitatory but not inhibitory neurons in the forebrain reduces GABAergic transmission in layer 5 pyramidal neurons in the prefrontal and somatosensory cortices. Loss of MeCP2 from cortical excitatory neurons reduces the number of GABAergic synapses in the cortex, and enhances the excitability of layer 5 pyramidal neurons. Using single-cell deletion of Mecp2 in layer 2/3 pyramidal neurons, we show that GABAergic transmission is reduced in neurons without MeCP2, but is normal in neighboring neurons with MeCP2. Together, these results suggest that MeCP2 in cortical excitatory neurons plays a critical role in the regulation of GABAergic transmission and cortical excitability. PMID:24523563
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Hamasaki, Sawako; Mukuda, Takao; Kaidoh, Toshiyuki; Yoshida, Masayuki; Uematsu, Kazumasa
2016-10-01
The forebrain lamina terminalis has not yet been examined for the role of osmosensing in teleosts, although the thirst center is well known to be present in this vascular permeable forebrain region in mammals. Here, we examined vascular permeability and neuronal responsiveness to dehydration in the lamina terminalis of the mudskipper, a euryhaline goby. Evans blue and N-hydroxysulfosuccinimide-biotin both bind to blood proteins, and are impermeable to the blood-brain barrier. Intraperitoneal injection of these probes stained the walls of the preoptic recess (PR) of the third ventricle, indicating increased vascular permeability in this region. When mudskippers kept in isotonic brackish water (ca. 11 psu) were challenged to seawater (ca. 34 psu) for 3 h, body water content showed a 1 % decrease, compared with mudskippers without hypertonic challenge. Simultaneously, the number of immunohistochemically identified cFos-expressing neurons in the anterior parvocellular preoptic nucleus (PPa) of the PR walls increased in a site-specific manner by approximately 1.6-fold compared with controls. Thus, these findings indicate that PPa neurons are activated, following dehydration in mudskippers. Taken together, the vascularly permeable PR walls may be involved in osmosensing, as in the mammalian thirst center.
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Opposing Shh and Fgf signals initiate nasotemporal patterning of the zebrafish retina.
Hernández-Bejarano, María; Gestri, Gaia; Spawls, Lana; Nieto-López, Francisco; Picker, Alexander; Tada, Masazumi; Brand, Michael; Bovolenta, Paola; Wilson, Stephen W; Cavodeassi, Florencia
2015-11-15
The earliest known determinants of retinal nasotemporal identity are the transcriptional regulators Foxg1, which is expressed in the prospective nasal optic vesicle, and Foxd1, which is expressed in the prospective temporal optic vesicle. Previous work has shown that, in zebrafish, Fgf signals from the dorsal forebrain and olfactory primordia are required to specify nasal identity in the dorsal, prospective nasal, optic vesicle. Here, we show that Hh signalling from the ventral forebrain is required for specification of temporal identity in the ventral optic vesicle and is sufficient to induce temporal character when activated in the prospective nasal retina. Consequently, the evaginating optic vesicles become partitioned into prospective nasal and temporal domains by the opposing actions of Fgfs and Shh emanating from dorsal and ventral domains of the forebrain primordium. In absence of Fgf activity, foxd1 expression is established irrespective of levels of Hh signalling, indicating that the role of Shh in promoting foxd1 expression is only required in the presence of Fgf activity. Once the spatially complementary expression of foxd1 and foxg1 is established, the boundary between expression domains is maintained by mutual repression between Foxd1 and Foxg1. © 2015. Published by The Company of Biologists Ltd.
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Sohrabji, F; Nordeen, E J; Nordeen, K W
1990-01-01
Area X, a large sexually dimorphic nucleus in the avian ventral forebrain, is part of a highly discrete system of interconnected nuclei that have been implicated in either song learning or adult song production. Previously, this nucleus has been included in the song system because of its substantial connections with other vocal control nuclei, and because its volume is positively correlated with the capacity for song. In order to directly assess the role of Area X in song behavior, this nucleus was bilaterally lesioned in both juvenile and adult zebra finches, using ibotenic acid. We report here that lesioning Area X disrupts normal song development in juvenile birds, but does not affect the production of stereotyped song by adult birds. Although juvenile-lesioned birds were consistently judged as being in earlier stages of vocal development than age-matched controls, they continued to produce normal song-like vocalizations. Thus, unlike the lateral magnocellular nucleus of the anterior neostriatum, another avian forebrain nucleus implicated in song learning, Area X does not seem to be necessary for sustaining production of juvenile song. Rather, the behavioral results suggest Area X is important for either the acquisition of a song model or the improvement of song through vocal practice.
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The effects of incubation temperature on the development of the cortical forebrain in a lizard.
Amiel, Joshua J; Bao, Shisan; Shine, Richard
2017-01-01
The embryos of egg-laying species are exposed to variable thermal regimes, which can influence not only the resultant hatchling's morphology (e.g., size, sex) and performance (e.g., locomotor speed), but also its cognitive performance (learning ability). To clarify the proximate basis for this latter effect, we incubated eggs of the scincid lizard Bassiana duperreyi under simulated 'hot' and 'cold' natural nest temperatures to examine the effect of incubation temperature on the structure of the telencephalon region of the forebrain. Hatchlings from low-temperature incubation had larger telencephalons (both in absolute terms and relative to body size) and larger neurons in their medial cortices, whereas the medial cortices of hatchlings from high-temperature incubation had fewer neurons overall, but greater neuronal density, and more neurons in certain areas. These temperature-induced differences in B. duperreyi forebrain development are consistent with (and may explain) the disparities in learning ability between hatchlings from our two incubation treatments. The phenotypic plasticity of lizard telencephalon anatomy in response to incubation temperature presents exciting opportunities for studies on the evolutionary and developmental determinants of intelligence in vertebrates, but also offers a cautionary tale. Global climate changes, wrought by anthropogenic activities, may directly modify brain structure in reptiles.