Dipeptidyl peptidase 4 – an important digestive peptidase in Tenebrio molitor larvae

USDA-ARS?s Scientific Manuscript database

Dipeptidyl peptidase 4 (DPP 4) is a proline specific serine peptidase that plays an important role in different regulatory processes in mammals. In this report, we isolated and characterized a unique secreted digestive DPP 4 from the anterior midgut of a stored product pest, Tenebrio molitor larvae ...

Proteomic Analysis of the Relationship between Metabolism and Nonhost Resistance in Soybean Exposed to Bipolaris maydis.

PubMed

Dong, Yumei; Su, Yuan; Yu, Ping; Yang, Min; Zhu, Shusheng; Mei, Xinyue; He, Xiahong; Pan, Manhua; Zhu, Youyong; Li, Chengyun

2015-01-01

Nonhost resistance (NHR) pertains to the most common form of plant resistance against pathogenic microorganisms of other species. Bipolaris maydis is a non-adapted pathogen affecting soybeans, particularly of maize/soybean intercropping systems. However, no experimental evidence has described the immune response of soybeans against B. maydis. To elucidate the molecular mechanism underlying NHR in soybeans, proteomics analysis based on two-dimensional polyacrylamide gel electrophoresis (2-DE) was performed to identify proteins involved in the soybean response to B. maydis. The spread of B. maydis spores across soybean leaves induced NHR throughout the plant, which mobilized almost all organelles and various metabolic processes in response to B. maydis. Some enzymes, including ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), mitochondrial processing peptidase (MPP), oxygen evolving enhancer (OEE), and nucleoside diphosphate kinase (NDKs), were found to be related to NHR in soybeans. These enzymes have been identified in previous studies, and STRING analysis showed that most of the protein functions related to major metabolic processes were induced as a response to B. maydis, which suggested an array of complex interactions between soybeans and B. maydis. These findings suggest a systematic NHR against non-adapted pathogens in soybeans. This response was characterized by an overlap between metabolic processes and response to stimulus. Several metabolic processes provide the soybean with innate immunity to the non-adapted pathogen, B. maydis. This research investigation on NHR in soybeans may foster a better understanding of plant innate immunity, as well as the interactions between plant and non-adapted pathogens in intercropping systems.

Proteomic Analysis of the Relationship between Metabolism and Nonhost Resistance in Soybean Exposed to Bipolaris maydis

PubMed Central

Dong, Yumei; Su, Yuan; Yu, Ping; Yang, Min; Zhu, Shusheng; Mei, Xinyue; He, Xiahong; Pan, Manhua; Zhu, Youyong; Li, Chengyun

2015-01-01

Nonhost resistance (NHR) pertains to the most common form of plant resistance against pathogenic microorganisms of other species. Bipolaris maydis is a non-adapted pathogen affecting soybeans, particularly of maize/soybean intercropping systems. However, no experimental evidence has described the immune response of soybeans against B. maydis. To elucidate the molecular mechanism underlying NHR in soybeans, proteomics analysis based on two-dimensional polyacrylamide gel electrophoresis (2-DE) was performed to identify proteins involved in the soybean response to B. maydis. The spread of B. maydis spores across soybean leaves induced NHR throughout the plant, which mobilized almost all organelles and various metabolic processes in response to B. maydis. Some enzymes, including ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), mitochondrial processing peptidase (MPP), oxygen evolving enhancer (OEE), and nucleoside diphosphate kinase (NDKs), were found to be related to NHR in soybeans. These enzymes have been identified in previous studies, and STRING analysis showed that most of the protein functions related to major metabolic processes were induced as a response to B. maydis, which suggested an array of complex interactions between soybeans and B. maydis. These findings suggest a systematic NHR against non-adapted pathogens in soybeans. This response was characterized by an overlap between metabolic processes and response to stimulus. Several metabolic processes provide the soybean with innate immunity to the non-adapted pathogen, B. maydis. This research investigation on NHR in soybeans may foster a better understanding of plant innate immunity, as well as the interactions between plant and non-adapted pathogens in intercropping systems. PMID:26513657

M13 phage peptide ZL4 exerts its targeted binding effect on schistosoma japonicum via alkaline phosphatase.

PubMed

Liu, Yan; Yang, Shenghui; Xiao, Jianhua; Yu, Liang; Chen, Li; Zou, Ju; Wang, Kegeng; Tan, Sijie; Yu, Zhengyang; Zeng, Qingren

2015-01-01

The present study was to determine the targeting effect of M13 phage peptide ZL4 (MppZL4) on Schistosoma japonicum (S.j). Mice infected with S.j were injected with MppZL4. Real-time PCR was used to detect the distribution and metabolism of MppZL4 in the livers and lungs of mice. In vivo refusion test was performed to detect the targeting of MppZL4. Western blotting was employed to determine the expression of MppZL4. Live imaging was used to detect the distribution of oligopeptide MppZL4. Immunohistochemistry was employed to determine MppZL4 location on adult S.j body surface. Gomori method was employed to detect the influence of oligopeptide MppZL4 on alkaline phosphatase activity. The distribution and metabolism of MppZL4 and M13KE are not significantly different from each other at each time point. The abundance of MppZL4 is changed as S.j migrates in mice. The targeted binding effect of MppZL4 varies at different stages. ZL4 oligopeptide targets S.j in mice. The specific binding sites of MppZL4 on S.j body are mainly located in syncytial cells. The binding sites of MppZL4 on S.j body surface might be ALP or ALP-related proteins. MppZL4 had targeted binding effect on S.j with its binding site being associated with proteins related to S.j alkaline phosphatase. S.j tegument had a specifically binding site with exogenous peptides, offering new means to explore the interactions between hosts and parasites. Additionally, MppZL4 can possibly be used as targeting molecules in worm-resistant drugs or as tracing molecules in imaging diagnosis technologies.

[Study on the interface of human hepatocyte/micropore polypropylene ultrafiltration membrane].

PubMed

Peng, Cheng-Hong; Han, Bao-San; Gao, Chang-You; Ma, Zu-Wei; Zhao, Zhi-Ming; Wang, Yong; Liu, Hong; Zhang, Gui-di; Yang, Mei-Juan

2004-09-02

To found a new interface of human hepatocyte/micropore polypropylene ultrafiltration membrane (MPP) with good cytocompatibility so as to construct bioartificial bioreactor with polypropylene hollow fibers in future. MPP ultrafiltration membrane underwent chemical grafting modification through ultraviolet irradiation and Fe(2+) reduction. The contact angles of MPP and the modified MPP membranes were measured. Human hepatic cells L-02 were cultured. MPP and modified MPP membranes were spread on the wells of culture plate and human hepatic cells and cytodex 3 were inoculated on them. Different kinds of microscopy were used to observe the morphology of these cells. The water contact angle of MPP and the modified MPP membranes decreased from 78 degrees +/- 5 degrees to 27 degrees +/- 4 degrees (P < 0.05), which indicated that the hydrophilicity of the membrane was improved obviously after the grafting modification. Human hepatocyte L-02 did not adhere to and spread on the modified MPP membrane surface, and only grew on the microcarrier cytodex 3 with higher density and higher proliferation ratio measured by MTT. Grafting modification of acrylamide on MPP membrane is a good method to improve the human hepatocyte cytocompatibility with MPP ultrafiltration membrane.

Production and partial characterization of serine and metallo peptidases secreted by Aspergillus fumigatus Fresenius in submerged and solid state fermentation.

PubMed

da Silva, Ronivaldo Rodrigues; de Freitas Cabral, Tatiana Pereira; Rodrigues, André; Cabral, Hamilton

2013-01-01

Enzyme production varies in different fermentation systems. Enzyme expression in different fermentation systems yields important information for improving our understanding of enzymatic production induction. Comparative studies between solid-state fermentation (SSF) using agro-industrial waste wheat bran and submerged fermentation (SmF) using synthetic media were carried out to determinate the best parameters for peptidase production by the fungus Aspergillus fumigatus Fresen. Variables tested include: the concentration of carbon and protein nitrogen sources, the size of the inoculum, the pH of the media, temperature, and the length of the fermentation process. The best peptidase production during SSF was obtained after 96 hours using wheat bran at 30 °C with an inoculum of 1 × 10(6) spores and yielded 1500 active units (U/mL). The best peptidase production using SmF was obtained after periods of 72 and 96 hours of fermentation in media containing 0.5% and 0.25% of casein, respectively, at a pH of 6.0 and at 30 °C and yielded 40 U/mL. We also found examples of catabolite repression of peptidase production under SmF conditions. Biochemical characterization of the peptidases produced by both fermentative processes showed optimum activity at pH 8.0 and 50 °C, and also showed that their proteolytic activity is modulated by surfactants. The enzymatic inhibition profile using phenylmethylsulfonyl fluoride (PMSF) in SmF and SSF indicated that both fermentative processes produced a serine peptidase. Additionally, the inhibitory effect of the ethylene-diaminetetraacetic acid (EDTA) chelating agent on the peptidase produced by SmF indicated that this fermentative process also produced a metallopeptidase.

New hydroxypyridinone iron-chelators as potential anti-neurodegenerative drugs.

PubMed

Arduino, Daniela; Silva, Daniel; Cardoso, Sandra M; Chaves, Silvia; Oliveira, Catarina R; Santos, M Amelia

2008-05-01

The neuroprotective action of a set of new hydroxypyridinone-based (3,4-HP) compounds (A, B and C), which are iron chelators extra-functionalized with a propargylamino group for potential MAO-B inhibition, was evaluated after cell treatment with MPP+ (an in vivo inducer of parkinsonism) and Abeta(1-40) and/or Abeta(1-42) peptides. Our results show that all these compounds improved cell viability in cells treated with MPP+ and Abeta(1-40) peptide or Abeta(1-42) peptide. In order to evaluate the cellular mechanisms underlying the activity of these compounds, we studied their protective role in caspase activation. All compounds tested were able to prevent MPP+ and Brefeldin A induced caspase-2 activation. They also showed quite effective in the inhibition of caspase-4 and caspase-3 activity, an effector caspase in the apoptotic process. Finally, detection of apoptotic-like cell death after cell exposure to MPP+ was also performed by TUNEL assay. Our results demonstrated that all tested compounds prevented DNA fragmentation by decreasing TUNEL positive cells. A, B and C were more effective than DFP (a 3,4-HP iron-chelating agent in clinical use) in MPP+ induced cell death. Therefore, these results evidenced a neuroprotective and antiapoptotic role for the compounds studied.

Anaerobic glycolysis protection against 1-methy-4-phenylpyridinium (MPP+) toxicity in C6 glioma cells.

PubMed

Williams, Zakia R; Goodman, Carl B; Soliman, Karam F A

2007-06-01

The neurotoxin 1-methy-4-phenylpyridinium (MPP(+)) is used for its' capacity to induce Parkinsonism through its inhibitory effects on mitochondrial complex I. This inhibition disrupts cellular energy formation and aerobic glycolysis. The objective of this study was to demonstrate that the toxic effect of mitochondrial aerobic pathway inhibition with MPP(+ )can be reduced by stimulating anaerobic glycolysis using glucose supplementation. In this study, C6 Glioma cell viability was examined in the presence of different concentrations of MPP alone and with the addition of glucose. The results obtained indicate that there was a significant increase (P < 0.001) in cell viability in cells treated with glucose and MPP(+ )verses cells treated with MPP(+ )alone. Fluorometric analysis using 100 microM Rhodamine 123 indicated mitochondrial membrane potential was not restored in MPP(+ )treated cells with glucose; however, normal cell viability was confirmed using 2 microg/ml Fluorescein diacetate. This dual fluorescence indicated mitochondrial damage from MPP(+ )while glucose augmented cell survival. Further confirmation of cell survival upon damage to the mitochondria was evident in TUNEL staining. Positive staining was prominent only in MPP(+) treatment groups alone, while control and co-treated groups exhibited little to no TUNEL staining. ATP measurements of all MPP(+) treated groups exhibited a significant (P < 0.001) decrease verses control. Groups co-treated with MPP(+ )and glucose revealed a significant increase (250 microM group: P < 0.001) in ATP. It was concluded from this study that glucose supplementation was able to sustain cellular viability and ATP production through anaerobic glycolysis despite the inhibitory effect of MPP(+ )on aerobic glycolysis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Argondizzo, Adam; Cui, Xuefeng; Wang, Cong

We investigate the spectroscopy and photoinduced electron dynamics within the conduction band of reduced rutile TiO2(110) surface by multiphoton photoemission (mPP) spectroscopy with wavelength tunable ultrafast (!20 fs) laser pulse excitation. Tuning the mPP photon excitation energy between 2.9 and 4.6 eV reveals a nearly degenerate pair of new unoccupied states located at 2.73 ± 0.05 and 2.85 ± 0.05 eV above the Fermi level, which can be analyzed through the polarization and sample azimuthal orientation dependence of the mPP spectra. Based on the calculated electronic structure and optical transition moments, as well as related spectroscopic evidence, we assign thesemore » resonances to transitions between Ti 3d bands of nominally t2g and eg symmetry, which are split by crystal field. The initial states for the optical transition are the reduced Ti3+ states of t2g symmetry populated by formation oxygen vacancy defects, which exist within the band gap of TiO2. Furthermore,we studied the electron dynamics within the conduction band of TiO2 by three-dimensional time-resolved pump-probe interferometric mPP measurements. The spectroscopic and time-resolved studies reveal competition between 2PP and 3PP processes where the t2g-eg transitions in the 2PP process saturate, and are overtaken by the 3PP process initiated by the band-gap excitation from the valence band of TiO2.« less

Roles of Autophagy in MPP+-Induced Neurotoxicity In Vivo: The Involvement of Mitochondria and α-Synuclein Aggregation

PubMed Central

Lin, Ming-Wei; Lei, Yen-Ping; Lin, Anya Maan-yuh

2014-01-01

Macroautophagy (also known as autophagy) is an intracellular self-eating mechanism and has been proposed as both neuroprotective and neurodestructive in the central nervous system (CNS) neurodegenerative diseases. In the present study, the role of autophagy involving mitochondria and α-synuclein was investigated in MPP+ (1-methyl-4-phenylpyridinium)-induced oxidative injury in chloral hydrate-anesthetized rats in vivo. The oxidative mechanism underlying MPP+-induced neurotoxicity was identified by elevated lipid peroxidation and heme oxygenase-1 levels, a redox-regulated protein in MPP+-infused substantia nigra (SN). At the same time, MPP+ significantly increased LC3-II levels, a hallmark protein of autophagy. To block MPP+-induced autophagy in rat brain, Atg7siRNA was intranigrally infused 4 d prior to MPP+ infusion. Western blot assay showed that in vivo Atg7siRNA transfection not only reduced Atg7 levels in the MPP+-infused SN but attenuated MPP+-induced elevation in LC3-II levels, activation of caspase 9 and reduction in tyrosine hydroxylase levels, indicating that autophagy is pro-death. The immunostaining study demonstrated co-localization of LC3 and succinate dehydrogenase (a mitochondrial complex II) as well as LC3 and α-synuclein, suggesting that autophagy may engulf mitochondria and α-synuclein. Indeed, in vivo Atg7siRNA transfection mitigated MPP+-induced reduction in cytochrome c oxidase. In addition, MPP+-induced autophagy differentially altered the α-synuclein aggregates in the infused SN. In conclusion, autophagy plays a prodeath role in the MPP+-induced oxidative injury by sequestering mitochondria in the rat brain. Moreover, our data suggest that the benefits of autophagy depend on the levels of α-synuclein aggregates in the nigrostriatal dopaminergic system of the rat brain. PMID:24646838

Interferon Gamma potentiates the injury caused by MPP(+) on SH-SY5Y cells, which is attenuated by the nitric oxide synthases inhibition.

PubMed

Titze-de-Almeida, Simoneide S; Lustosa, Cátia Faria; Horst, Camila Hillesheim; Bel, Elaine Del; Titze-de-Almeida, Ricardo

2014-12-01

This study examined whether the cytokine interferon (IFN) gamma plays a role in the injury of SH-SY5Y cells caused by MPP(+) (1-methyl-4-phenylpyridinium). First of all, IFN-gamma sensitized cells to the neurotoxin MPP(+), as determined by MTT (3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide) assay. MPP(+)-injured cells showed higher reactive oxygen species (ROS) levels, which was reinforced by IFN-gamma. The injury triggered a marked expression of the neuronal NOS (nNOS) enzyme. L-NAME [N(ω)-nitro-L-arginine methyl ester, a non-specific NOS inhibitor] reestablished the cell viability after IFN-gamma challenging, and recovered cells from MPP(+) injury (95.0 vs. 84.7 %; P < 0.05). Seven-NI (7-nitroindazole, a nNOS inhibitor) protected cells against the injury by MPP(+) co-administered with IFN-gamma. Both inhibitors restrained the apoptosis of SH-SY5Y cells caused by MPP(+)/IFN-gamma. Regarding oxidative stress, L-NAME and 7-NI attenuated the increase in ROS levels caused by MPP(+) (45.3 or 48.4 vs. 87.9 %, P < 0.05). Indeed, L-NAME was more effective than 7-NI for reducing oxidative stress caused by MPP(+) under IFN-gamma exposition. The nNOS gene silencing by small-interfering RNAs recovered cells challenged by IFN-gamma (24 h), or MPP(+) (8 h). In conclusion, IFN-gamma sensitizes cells to MPP(+)-induced injury, also causing an increase in ROS levels. Pretreating cells with L-NAME or 7-NI reverts both the oxidative stress and apoptosis triggered by the neurotoxin MPP(+). Taking together, our data reinforce that IFN-gamma and NOS enzymes play a role in oxidative stress and dopaminergic cell death triggered by MPP(+).

Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum

PubMed Central

Straub, Sandrine; Hirsch, Philipp E.; Burkhardt-Holm, Patricia

2017-01-01

Research on the uptake and effects of bioplastics by aquatic organisms is still in its infancy. Here, we aim to advance the field by comparing uptake and effects of microplastic particles (MPP) of a biodegradable bioMPP (polyhydroxybutyrate (PHB)) and petroleum-based MPP (polymethylmethacrylate (PMMA)) in the freshwater amphipod Gammarus fossarum. Ingestion of both MPP in different particle sizes (32–250 µm) occurred after 24 h, with highest ingestion of particles in the range 32–63 µm and almost complete egestion after 64 h. A four-week effect-experiment showed a significant decrease of the assimilation efficiency in amphipods exposed to the petroleum-based MPP from week two onwards. The petroleum-based PMMA affected assimilation efficiency significantly in contrast to the biodegradable PHB, but overall differences in direct comparison of MPP types were small. Both MPP types led to a significantly lower wet weight gain relative to the control treatments. After four weeks, differences between both MPP types and silica, used as a natural particle control, were detected. In summary, these results suggest that both MPP types provoke digestive constraints on the amphipods, which go beyond those of natural non-palatable particles. This highlights the need for more detailed research comparing environmental effects of biodegradable and petroleum-based MPP and testing those against naturally occurring particle loads. PMID:28703776

The Crude Skin Secretion of the Pepper Frog Leptodactylus labyrinthicus Is Rich in Metallo and Serine Peptidases

PubMed Central

Libério, Michelle da Silva; Bastos, Izabela M. D.; Pires Júnior, Osmindo R.; Fontes, Wagner; Santana, Jaime M.; Castro, Mariana S.

2014-01-01

Peptidases are ubiquitous enzymes involved in diverse biological processes. Fragments from bioactive peptides have been found in skin secretions from frogs, and their presence suggests processing by peptidases. Thus, the aim of this work was to characterize the peptidase activity present in the skin secretion of Leptodactylus labyrinthicus. Zymography revealed the presence of three bands of gelatinase activity of approximately 60 kDa, 66 kDa, and 80 kDa, which the first two were calcium-dependent. These three bands were inhibited either by ethylenediaminetetraacetic acid (EDTA) and phenathroline; thus, they were characterized as metallopeptidases. Furthermore, the proteolytic enzymes identified were active only at pH 6.0–10.0, and their activity increased in the presence of CHAPS or NaCl. Experiments with fluorogenic substrates incubated with skin secretions identified aminopeptidase activity, with cleavage after leucine, proline, and alanine residues. This activity was directly proportional to the protein concentration, and it was inhibited in the presence of metallo and serine peptidase inhibitors. Besides, the optimal pH for substrate cleavage was determined to be 7.0–8.0. The results of the in gel activity assay showed that all substrates were hydrolyzed by a 45 kDa peptidase. Gly-Pro-AMC was also cleaved by a peptidase greater than 97 kDa. The data suggest the presence of dipeptidyl peptidases (DPPs) and metallopeptidases; however, further research is necessary. In conclusion, our work will help to elucidate the implication of these enzymatic activities in the processing of the bioactive peptides present in frog venom, expanding the knowledge of amphibian biology. PMID:24906116

Bacillus thuringiensis Cry3Aa protoxin intoxication of Tenebrio molitor induces widespread changes in the expression of serine peptidase transcripts.

PubMed

Oppert, Brenda; Martynov, Alexander G; Elpidina, Elena N

2012-09-01

The yellow mealworm, Tenebrio molitor, is a pest of stored grain products and is sensitive to the Bacillus thuringiensis (Bt) Cry3Aa toxin. As digestive peptidases are a determining factor in Cry toxicity and resistance, we evaluated the expression of peptidase transcripts in the midgut of T. molitor larvae fed either a control or Cry3Aa protoxin diet for 24 h (RNA-Seq), or in larvae exposed to the protoxin for 6, 12, or 24 h (microarrays). Cysteine peptidase transcripts (9) were similar to cathepsins B, L, and K, and their expression did not vary more than 2.5-fold in control and Cry3Aa-treated larvae. Serine peptidase transcripts (48) included trypsin, chymotrypsin and chymotrypsin-like, elastase 1-like, and unclassified serine peptidases, as well as homologs lacking functional amino acids. Highly expressed trypsin and chymotrypsin transcripts were severely repressed, and most serine peptidase transcripts were expressed 2- to 15-fold lower in Cry3Aa-treated larvae. Many serine peptidase and homolog transcripts were found only in control larvae. However, expression of a few serine peptidase transcripts was increased or found only in Cry3Aa-treated larvae. Therefore, Bt intoxication significantly impacted the expression of serine peptidases, potentially important in protoxin processing, while the insect maintained the production of critical digestive cysteine peptidases. Published by Elsevier Inc.

DLP1-Dependent Mitochondrial Fragmentation Mediates 1-methyl-4-phenylpyridinium Toxicity in Neurons: Implications for Parkinson's Disease

PubMed Central

Wang, Xinglong; Su, Bo; Liu, Wanhong; He, Xiaohua; Gao, Yuan; Castellani, Rudy J.; Perry, George; Smith, Mark A.; Zhu, Xiongwei

2011-01-01

SUMMARY Selective degeneration of nigrostriatal dopaminergic neurons in Parkinson disease (PD) can be modeled by the administration of the neurotoxin 1-methyl-4-phenylpyridinium (MPP+). Since abnormal mitochondrial dynamics are increasingly implicated in the pathogenesis of PD, in this study, we investigated the effect of MPP+ on mitochondrial dynamics and assessed temporal and causal relationship with other toxic effects induced by MPP+ in neuronal cells. In SH-SY5Y cells, MPP+ causes a rapid increase in mitochondrial fragmentation followed by a second wave of increase in mitochondrial fragmentation, along with increased DLP1 expression and mitochondrial translocation. Genetic inactivation of DLP1 completely blocks MPP+-induced mitochondrial fragmentation. Notably, this approach partially rescues MPP+-induced decline in ATP levels and ATP/ADP ratio and increased [Ca2+]i and almost completely prevents increased reactive oxygen species production, loss of mitochondrial membrane potential, enhanced autophagy and cell death, suggesting that mitochondria fragmentation is an upstream event that mediates MPP+-induced toxicity. On the other hand, thiol antioxidant NAC or glutamate receptor antagonist D-AP5 also partially alleviate MPP+-induced mitochondrial fragmentation, suggesting a vicious spiral of events contributes to MPP+-induced toxicity. We further validated our findings in primary rat midbrain dopaminergic neurons that 0.5 μM MPP+ induced mitochondrial fragmentation only in TH-positive dopaminergic neurons in a similar pattern to that in SH-SY5Y cells but had no effects on these mitochondrial parameters in TH-negative neurons. Overall, these findings suggest that DLP1-dependent mitochondrial fragmentation plays a crucial role in mediating MPP+-induced mitochondria abnormalities and cellular dysfunction and may represent a novel therapeutic target for PD. PMID:21615675

Immunolocalization of tripeptidyl peptidase II, a cholecystokinin-inactivating enzyme, in rat brain.

PubMed

Facchinetti, P; Rose, C; Rostaing, P; Triller, A; Schwartz, J C

1999-01-01

Tripeptidyl peptidase II (EC 3.4.14.10) is a serine peptidase apparently involved in the inactivation of cholecystokinin octapeptide [Rose C. et al. (1996) Nature 380, 403-409]. We have compared its distribution with that of cholecystokinin in rat brain, using a polyclonal antibody raised against a highly purified preparation for immunohistochemistry at the photon and electron microscope levels. Tripeptidyl peptidase II-like immunoreactivity was mostly detected in neurons, and also in ependymal cells and choroid plexuses, localizations consistent with a possible participation of the peptidase in the inactivation of cholecystokinin circulating in the cerebrospinal fluid. Immunoreactivity was mostly detected in cell bodies, large processes and, to a lesser extent, axons of various neuronal populations. Their localization, relative to that of cholecystokinin terminals, appears to define three distinct situations. The first corresponds to neurons with high immunoreactivity in areas containing cholecystokinin terminals, as in the cerebral cortex or hippocampal formation, where pyramidal cell bodies and processes surrounded by cholecystokinin axons were immunoreactive. A similar situation was encountered in many other areas, namely along the pathways through which cholecystokinin controls satiety, i.e. in sensory vagal neurons, the nucleus tractus solitarius and hypothalamic nuclei. The second situation corresponds to cholecystokinin neuronal populations containing tripeptidyl peptidase II-like immunoreactivity, as in neurons of the supraoptic or paraventricular nuclei, axons in the median eminence or nigral neurons. In both situations, localization of tripeptidyl peptidase II-like immunoreactivity is consistent with a role in cholecystokinin inactivation. The third situation corresponds to areas with mismatches, such as the cerebellum, a region devoid of cholecystokinin, but in which Purkinje cells displayed high tripeptidyl peptidase II-like immunoreactivity, possibly related to a role in the inactivation of neuropeptides other than cholecystokinin. Also, some areas with cholecystokinin terminals, e.g., the molecular layer of the cerebral cortex, were devoid of tripeptidyl peptidase II-like immunoreactivity, suggesting that processes other than cleavage by tripeptidyl peptidase II may be involved in cholecystokinin inactivation. Tripeptidyl peptidase II-like immunoreactivity was also detected at the ultrastructural level in the cerebral cortex and hypothalamus using either immunoperoxidase or silver-enhanced immunogold detection. It was mainly associated with the cytoplasm of neuronal somata and dendrites, often in the vicinity of reticulum cisternae, Golgi apparatus or vesicles, and with the inner side of the dendritic plasma membrane. Hence, whereas a fraction of tripeptidyl peptidase II-like immunoreactivity localization at the cellular level is consistent with its alleged function in cholecystokinin octapeptide inactivation, its association with the outside plasma membrane of neurons remains to be confirmed.

MPP+-Lesioned Mice: an Experimental Model of Motor, Emotional, Memory/Learning, and Striatal Neurochemical Dysfunctions.

PubMed

Cunha, Mauricio P; Pazini, Francis L; Lieberknecht, Vicente; Budni, Josiane; Oliveira, Ágatha; Rosa, Júlia M; Mancini, Gianni; Mazzardo, Leidiane; Colla, André R; Leite, Marina C; Santos, Adair R S; Martins, Daniel F; de Bem, Andreza F; Gonçalves, Carlos Alberto S; Farina, Marcelo; Rodrigues, Ana Lúcia S

2017-10-01

The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induces motor and nonmotor dysfunctions resembling Parkinson's disease (PD); however, studies investigating the effects of 1-methyl-4-phenylpyridinium (MPP + ), an active oxidative product of MPTP, are scarce. This study investigated the behavioral and striatal neurochemical changes (related to oxidative damage, glial markers, and neurotrophic factors) 24 h after intracerebroventricular administration of MPP + (1.8-18 μg/mouse) in C57BL6 mice. MPP + administration at high dose (18 μg/mouse) altered motor parameters, since it increased the latency to leave the first quadrant and reduced crossing, rearing, and grooming responses in the open-field test and decreased rotarod latency time. MPP + administration at low dose (1.8 μg/mouse) caused specific nonmotor dysfunctions as it produced a depressive-like effect in the forced swim test and tail suspension test, loss of motivational and self-care behavior in the splash test, anxiety-like effect in the elevated plus maze test, and short-term memory deficit in the step-down inhibitory avoidance task, without altering ambulation. MPP + at doses of 1.8-18 μg/mouse increased tyrosine hydroxylase (TH) immunocontent and at 18 μg/mouse increased α-synuclein and decreased parkin immunocontent. The astrocytic calcium-binding protein S100B and glial fibrillary acidic protein (GFAP)/S100B ratio was decreased following MPP + administration (18 μg/mouse). At this highest dose, MPP + increased the ionized calcium-binding adapter molecule 1 (Iba-1) immunocontent, suggesting microglial activation. Also, MPP + at a dose of 18 μg/mouse increased thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels and increased glutathione peroxidase (GPx) and hemeoxygenase-1 (HO-1) immunocontent, suggesting a significant role for oxidative stress in the MPP + -induced striatal damage. MPP + (18 μg/mouse) also increased striatal fibroblast growth factor 2 (FGF-2) and brain-derived neurotrophic factor (BDNF) levels. Moreover, MPP + decreased tropomyosin receptor kinase B (TrkB) immunocontent. Finally, MPP + (1.8-18 μg/mouse) increased serum corticosterone levels and did not alter acetylcholinesterase (AChE) activity in the striatum but increased it in cerebral cortex and hippocampus. Collectively, these results indicate that MPP + administration at low doses may be used as a model of emotional and memory/learning behavioral deficit related to PD and that MPP + administration at high dose could be useful for analysis of striatal dysfunctions associated with motor deficits in PD.

Peptidase inhibitors in tick physiology.

PubMed

Parizi, L F; Ali, A; Tirloni, L; Oldiges, D P; Sabadin, G A; Coutinho, M L; Seixas, A; Logullo, C; Termignoni, C; DA Silva Vaz, I

2018-06-01

Peptidase inhibitors regulate a wide range of physiological processes involved in the interaction between hematophagous parasites and their hosts, including tissue remodeling, the immune response and blood coagulation. In tick physiology, peptidase inhibitors have a crucial role in adaptation to improve parasitism mechanisms, facilitating blood feeding by interfering with defense-related host peptidases. Recently, a larger number of studies on this topic led to the description of several new tick inhibitors displaying interesting novel features, for example a role in pathogen transmission to the host. A comprehensive review discussing these emerging concepts can therefore shed light on peptidase inhibitor functions, their relevance to tick physiology and their potential applications. Here, we summarize and examine the general characteristics, functional diversity and action of tick peptidase inhibitors with known physiological roles in the tick-host-pathogen interaction. © 2017 The Royal Entomological Society.

Phytomonas serpens: cysteine peptidase inhibitors interfere with growth, ultrastructure and host adhesion.

PubMed

Santos, André L S; d'Avila-Levy, Claudia M; Dias, Felipe A; Ribeiro, Rachel O; Pereira, Fernanda M; Elias, Camila G R; Souto-Padrón, Thaïs; Lopes, Angela H C S; Alviano, Celuta S; Branquinha, Marta H; Soares, Rosangela M A

2006-01-01

In this study, we report the ultrastructural and growth alterations caused by cysteine peptidase inhibitors on the plant trypanosomatid Phytomonas serpens. We showed that the cysteine peptidase inhibitors at 10 microM were able to arrest cellular growth as well as promote alterations in the cell morphology, including the parasites becoming short and round. Additionally, iodoacetamide induced ultrastructural alterations, such as disintegration of cytoplasmic organelles, swelling of the nucleus and kinetoplast-mitochondrion complex, which culminated in parasite death. Leupeptin and antipain induced the appearance of microvillar extensions and blebs on the cytoplasmic membrane, resembling a shedding process. A 40 kDa cysteine peptidase was detected in hydrophobic and hydrophilic phases of P. serpens cells after Triton X-114 extraction. Additionally, we have shown through immunoblotting that anti-cruzipain polyclonal antibodies recognised two major polypeptides in P. serpens, including a 40 kDa component. Flow cytometry analysis confirmed that this cruzipain-like protein has a location on the cell surface. Ultrastructural immunocytochemical analysis demonstrated the presence of the cruzipain-like protein on the surface and in small membrane fragments released from leupeptin-treated parasites. Furthermore, the involvement of cysteine peptidases of P. serpens in the interaction with explanted salivary glands of the phytophagous insect Oncopeltus fasciatus was also investigated. When P. serpens cells were pre-treated with either cysteine peptidase inhibitors or anti-cruzipain antibody, a significant reduction of the interaction process was observed. Collectively, these results suggest that cysteine peptidases participate in several biological processes in P. serpens including cell growth and interaction with the invertebrate vector.

Selective chromogenic and fluorogenic peptide substrates for the assay of cysteine peptidases in complex mixtures.

PubMed

Semashko, Tatiana A; Vorotnikova, Elena A; Sharikova, Valeriya F; Vinokurov, Konstantin S; Smirnova, Yulia A; Dunaevsky, Yakov E; Belozersky, Mikhail A; Oppert, Brenda; Elpidina, Elena N; Filippova, Irina Y

2014-03-15

This study describes the design, synthesis, and use of selective peptide substrates for cysteine peptidases of the C1 papain family, important in many biological processes. The structure of the newly synthesized substrates is Glp-Xaa-Ala-Y (where Glp=pyroglutamyl; Xaa=Phe or Val; and Y=pNA [p-nitroanilide], AMC [4-amino-7-methylcoumaride], or AFC [4-amino-7-trifluoromethyl-coumaride]). Substrates were synthesized enzymatically to guarantee selectivity of the reaction and optical purity of the target compounds, simplifying the scheme of synthesis and isolation of products. The hydrolysis of the synthesized substrates was evaluated by C1 cysteine peptidases from different organisms and with different functions, including plant enzymes papain, bromelain, ficin, and mammalian lysosomal cathepsins B and L. The new substrates were selective for C1 cysteine peptidases and were not hydrolyzed by serine, aspartic, or metallo peptidases. We demonstrated an application of the selectivity of the synthesized substrates during the chromatographic separation of a multicomponent set of digestive peptidases from a beetle, Tenebrio molitor. Used in combination with the cysteine peptidase inhibitor E-64, these substrates were able to differentiate cysteine peptidases from peptidases of other classes in midgut extracts from T. molitor larvae and larvae of the genus Tribolium; thus, they are useful in the analysis of complex mixtures containing peptidases from different classes. Published by Elsevier Inc.

Structure and function of yeast glutaredoxin 2 depend on postranslational processing and are related to subcellular distribution.

PubMed

Porras, Pablo; McDonagh, Brian; Pedrajas, Jose Rafael; Bárcena, J Antonio; Padilla, C Alicia

2010-04-01

We have previously shown that glutaredoxin 2 (Grx2) from Saccharomyces cerevisiae localizes at 3 different subcellular compartments, cytosol, mitochondrial matrix and outer membrane, as the result of different postranslational processing of one single gene. Having set the mechanism responsible for this remarkable phenomenon, we have now aimed at defining whether this diversity of subcellular localizations correlates with differences in structure and function of the Grx2 isoforms. We have determined the N-terminal sequence of the soluble mitochondrial matrix Grx2 by mass spectrometry and have determined the exact cleavage site by Mitochondrial Processing Peptidase (MPP). As a consequence of this cleavage, the mitochondrial matrix Grx2 isoform possesses a basic tetrapeptide extension at the N-terminus compared to the cytosolic form. A functional relationship to this structural difference is that mitochondrial Grx2 displays a markedly higher activity in the catalysis of GSSG reduction by the mitochondrial dithiol dihydrolipoamide. We have prepared Grx2 mutants affected on key residues inside the presequence to direct the protein to one single cellular compartment; either the cytosol, the mitochondrial membrane or the matrix and have analyzed their functional phenotypes. Strains expressing Grx2 only in the cytosol are equally sensitive to H(2)O(2) as strains lacking the gene, whereas those expressing Grx2 exclusively in the mitochondrial matrix are more resistant. Mutations on key basic residues drastically affect the cellular fate of the protein, showing that evolutionary diversification of Grx2 structural and functional properties are strictly dependent on the sequence of the targeting signal peptide. Copyright 2009 Elsevier B.V. All rights reserved.

Increased Serum Interleukin-10 but not Interleukin-4 Level in Children with Mycoplasma pneumoniae Pneumonia.

PubMed

Medjo, Biljana; Atanaskovic-Markovic, Marina; Nikolic, Dimitrije; Radic, Snezana; Lazarevic, Ivana; Cirkovic, Ivana; Djukic, Slobodanka

2017-08-01

Mycoplasma pneumoniae (MP) is a common cause of community-acquired pneumonia in children, and it has been associated with wheezing. The aim of this study was to examine the serum level of interleukin (IL)-4 and IL-10 in children with Mycoplasma pneumoniae pneumonia (MPP) and to analyse them in relation to the presence of wheezing. The study included 166 children with radiologically confirmed pneumonia. MP infection was confirmed by enzyme-linked immunosorbent assay (ELISA) serum MP-IgM and MP-IgG test and throat swab MP DNA with real-time polymerase chain reaction. Serum levels of IL-4 and IL-10 were measured using ELISA. There was no significant difference in serum level of IL-4 between children with MPP and those with non-MPP. Among children with MPP, we found similar level of IL-4 regardless of the personal and family history of allergy and asthma or the presence of wheezing. A significantly higher level of IL-10 was found in children with MPP than in children with non-MPP (32.92±18.582 vs. 27.01±14.100 pg/ml, p =0.022). Furthermore, wheezing children with MPP had a significantly higher level of IL-10 than children with MPP without wheezing (43.75±26.644 vs. 27.50±10.211 pg/ml, p=0.027). Our results show significantly increased serum level of IL-10 in children with MPP, which was significantly higher in children with wheezing. These findings may suggest a role of IL-10 in the pathogenesis of MPP and in the occurrence of wheezing during acute MP infection. © The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Striatal MPP+ levels do not necessarily correlate with striatal dopamine levels after MPTP treatment in mice.

PubMed

Vaglini, F; Fascetti, F; Tedeschi, D; Cavalletti, M; Fornai, F; Corsini, G U

1996-06-01

The present study offers confirmation of the fact that an MAO-B inhibitor, (-) deprenyl and a DA uptake blocker, GBR-12909, prevent MPTP-induced striatal DA decrease. This protective effect is accompanied by an almost complete prevention of MPP+ production induced by (-) deprenyl and an accelerated MPP+ clearance induced by GBR-12909 within the striatum. Similarly, the MPTP toxicity enhancers, DDC and acetaldehyde, both increase striatal MPP+ levels, as previously reported. On the contrary, the treatment with MK 801, although uneffective in preventing the long-term MPTP-induced striatal DA decrease, causes an increase in the striatal amount of MPP+. In a similar way, the administration of nicotine in combination with MPTP produces a significant increase in the levels of striatal MPP+, which does not elicit any effect on striatal DA. The effect of clonidine is consistent with these results and in sharp contrast with the current belief that a direct relationship exists between striatal MPP+ concentrations and the degree of MPTP-induced depletion of striatal DA. In this study, using different treatments, we failed to confirm the correlation between MPP+ striatal levels and dopaminergic lesions after MPTP administration in mice. We suggest that this correlation is not a rule and exceptions may depend on a different compartimentalization of the toxic metabolite.

Role of mitochondrial dysfunction in neurotoxicity of MPP+: partial protection of PC12 cells by acetyl-L-carnitine.

PubMed

Virmani, Ashraf; Gaetani, Franco; Binienda, Zbigniew; Xu, Alex; Duhart, Helen; Ali, Syed F

2004-10-01

The damage to the central nervous system that is observed after administration of either methamphetamine (METH) or 1-methyl-4-phenylpyridinium (MPP+), the neurotoxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), is known to be linked to dopamine (DA). The underlying neurotoxicity mechanism for both METH and MPP+ seem to involve free radical formation and impaired mitochondrial function. The MPP+ is thought to selectively kill nigrostriatal dopaminergic neurons by inhibiting mitochondrial complex I, with cell death being attributed to oxidative stress damage to these vulnerable DA neurons. In the present study, MPP+ was shown to significantly inhibit the response to MTT by cultured PC12 cells. This inhibitory action of MPP+ could be partially reversed by the co-incubation of the cells with the acetylated form of carnitine, acetyl-L-carnitine (ALC). Since at least part of the toxic action of MPP+ is related to mitochondrial inhibition, the partial reversal of the inhibition of MTT response by ALC could involve a partial restoration of mitochondrial function. The role carnitine derivatives, such as ALC, play in attenuating MPP+ and METH-evoked toxicity is still under investigation to elucidate the contribution of mitochondrial dysfunction in mechanisms of neurotoxicity.

Computations on the massively parallel processor at the Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Strong, James P.

1991-01-01

Described are four significant algorithms implemented on the massively parallel processor (MPP) at the Goddard Space Flight Center. Two are in the area of image analysis. Of the other two, one is a mathematical simulation experiment and the other deals with the efficient transfer of data between distantly separated processors in the MPP array. The first algorithm presented is the automatic determination of elevations from stereo pairs. The second algorithm solves mathematical logistic equations capable of producing both ordered and chaotic (or random) solutions. This work can potentially lead to the simulation of artificial life processes. The third algorithm is the automatic segmentation of images into reasonable regions based on some similarity criterion, while the fourth is an implementation of a bitonic sort of data which significantly overcomes the nearest neighbor interconnection constraints on the MPP for transferring data between distant processors.

Report from the MPP Working Group to the NASA Associate Administrator for Space Science and Applications

NASA Technical Reports Server (NTRS)

Fischer, James R.; Grosch, Chester; Mcanulty, Michael; Odonnell, John; Storey, Owen

1987-01-01

NASA's Office of Space Science and Applications (OSSA) gave a select group of scientists the opportunity to test and implement their computational algorithms on the Massively Parallel Processor (MPP) located at Goddard Space Flight Center, beginning in late 1985. One year later, the Working Group presented its report, which addressed the following: algorithms, programming languages, architecture, programming environments, the way theory relates, and performance measured. The findings point to a number of demonstrated computational techniques for which the MPP architecture is ideally suited. For example, besides executing much faster on the MPP than on conventional computers, systolic VLSI simulation (where distances are short), lattice simulation, neural network simulation, and image problems were found to be easier to program on the MPP's architecture than on a CYBER 205 or even a VAX. The report also makes technical recommendations covering all aspects of MPP use, and recommendations concerning the future of the MPP and machines based on similar architectures, expansion of the Working Group, and study of the role of future parallel processors for space station, EOS, and the Great Observatories era.

Tripeptidyl Peptidase II Mediates Levels of Nuclear Phosphorylated ERK1 and ERK2*

PubMed Central

Wiemhoefer, Anne; Stargardt, Anita; van der Linden, Wouter A.; Renner, Maria C.; van Kesteren, Ronald E.; Stap, Jan; Raspe, Marcel A.; Tomkinson, Birgitta; Kessels, Helmut W.; Ovaa, Huib; Overkleeft, Herman S.; Florea, Bogdan; Reits, Eric A.

2015-01-01

Tripeptidyl peptidase II (TPP2) is a serine peptidase involved in various biological processes, including antigen processing, cell growth, DNA repair, and neuropeptide mediated signaling. The underlying mechanisms of how a peptidase can influence this multitude of processes still remain unknown. We identified rapid proteomic changes in neuroblastoma cells following selective TPP2 inhibition using the known reversible inhibitor butabindide, as well as a new, more potent, and irreversible peptide phosphonate inhibitor. Our data show that TPP2 inhibition indirectly but rapidly decreases the levels of active, di-phosphorylated extracellular signal-regulated kinase 1 (ERK1) and ERK2 in the nucleus, thereby down-regulating signal transduction downstream of growth factors and mitogenic stimuli. We conclude that TPP2 mediates many important cellular functions by controlling ERK1 and ERK2 phosphorylation. For instance, we show that TPP2 inhibition of neurons in the hippocampus leads to an excessive strengthening of synapses, indicating that TPP2 activity is crucial for normal brain function. PMID:26041847

Effects of Agmatine on Depressive-Like Behavior Induced by Intracerebroventricular Administration of 1-Methyl-4-phenylpyridinium (MPP(+)).

PubMed

Moretti, Morgana; Neis, Vivian Binder; Matheus, Filipe Carvalho; Cunha, Mauricio Peña; Rosa, Priscila Batista; Ribeiro, Camille Mertins; Rodrigues, Ana Lúcia S; Prediger, Rui Daniel

2015-10-01

Considering that depression is a common non-motor comorbidity of Parkinson's disease and that agmatine is an endogenous neuromodulator that emerges as a potential agent to manage diverse central nervous system disorders, this study investigated the antidepressant-like effect of agmatine in mice intracerebroventricularly (i.c.v.) injected with the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)). Male C57BL6 mice were treated with agmatine (0.0001, 0.1 or 1 mg/kg) and 60 min later the animals received an i.c.v. injection of MPP(+) (1.8 µg/site). Twenty-four hours after MPP(+) administration, immobility time, anhedonic behavior, and locomotor activity were evaluated in the tail suspension test (TST), splash test, and open field test, respectively. Using Western blot analysis, we investigated the putative modulation of MPP(+) and agmatine on striatal and frontal cortex levels of tyrosine hydroxylase (TH) and brain-derived neurotrophic factor (BDNF). MPP(+) increased the immobility time of mice in the TST, as well as induced an anhedonic-like behavior in the splash test, effects which were prevented by pre-treatment with agmatine at the three tested doses. Neither drug, alone or in combination, altered the locomotor activity of mice. I.c.v. administration of MPP(+) increased the striatal immunocontent of TH, an effect prevented by the three tested doses of agmatine. MPP(+) and agmatine did not alter the immunocontent of BDNF in striatum and frontal cortex. These results demonstrate for the first time the antidepressant-like effects of agmatine in an animal model of depressive-like behavior induced by the dopaminergic neurotoxin MPP(+).

Binding preference of p62 towards LC3-ll during dopaminergic neurotoxin-induced impairment of autophagic flux.

PubMed

Lim, Junghyun; Kim, Hyun-Wook; Youdim, Moussa B H; Rhyu, Im Joo; Choe, Kwang-Min; Oh, Young J

2011-01-01

Accumulating evidence has revealed that autophagy may be beneficial for treatment of neurodegenerative diseases through removal of abnormal protein aggregates. However, the critical autophagic events during neurodegeneration remain to be elucidated. Here, we investigated whether prototypic autophagic events occur in the MN9D dopaminergic neuronal cell line upon exposure to N-methyl-4-phenylpyridinium (MPP (+) ), a well-known dopaminergic neurotoxin. MPP (+) treatment induced both morphological and biochemical characteristics of autophagy, such as accumulation of autophagic vacuoles and LC3-II form and decreased p62 levels. Further investigation revealed that these phenomena were largely the consequences of blocked autophagic flux. Following MPP (+) treatment, levels of LC3-II formed and p62 dramatically increased in the Triton X-100-insoluble fraction. Levels of ubiquitinated proteins also increased in this fraction. Further colocalization analyses revealed that the punctated spots positive for both p62 and LC3 were more intense following MPP (+) treatment, suggesting drug-induced enrichment of these two proteins in the insoluble fraction. Intriguingly, reciprocal immunoprecipitation analysis revealed that p62 mainly precipitated with LC3-II form following MPP (+) treatment. Transient transfection of the mutant form of Atg4B, Atg4B (C74A) , which inhibits LC3 processing, dramatically decreased binding between p62 and LC3-II form. Taken together, our results indicate that p62 can be efficiently localized to autophagic compartments via preferential binding with LC3-II form. This colocalization may assist in removal of detergent-insoluble forms of damaged cellular proteins during dopaminergic neurotoxin-induced impairment of autophagic flux.

The distinguishing signature of Magnetic Penrose Process

NASA Astrophysics Data System (ADS)

Dadhich, Naresh; Tursunov, Arman; Ahmedov, Bobomurat; Stuchlík, Zdeněk

2018-04-01

In this Letter, we wish to point out that the distinguishing feature of Magnetic Penrose process (MPP) is its super high efficiency exceeding 100% (which was established in mid 1980s for discrete particle accretion) of extraction of rotational energy of a rotating black hole electromagnetically for a magnetic field of milli Gauss order. Another similar process, which is also driven by electromagnetic field, is Blandford-Znajek mechanism (BZ), which could be envisaged as high magnetic field limit MPP as it requires threshold magnetic field of order 104G. Recent simulation studies of fully relativistic magnetohydrodynamic flows have borne out super high efficiency signature of the process for high magnetic field regime; viz BZ. We would like to make a clear prediction that similar simulation studies of MHD flows for low magnetic field regime, where BZ would be inoperative, would also have super efficiency.

Chemically treated plasma Aβ is a potential blood-based biomarker for screening cerebral amyloid deposition.

PubMed

Park, Jong-Chan; Han, Sun-Ho; Cho, Hyun Jin; Byun, Min Soo; Yi, Dahyun; Choe, Young Min; Kang, Seokjo; Jung, Eun Sun; Won, Su Jin; Kim, Eun Hye; Kim, Yu Kyeong; Lee, Dong Young; Mook-Jung, Inhee

2017-03-22

Plasma β-amyloid (Aβ) is a potential candidate for an Alzheimer's disease (AD) biomarker because blood is an easily accessible bio-fluid, which can be collected routinely, and Aβ is one of the major hallmarks of AD pathogenesis in the brain. However, the association between plasma Aβ levels and AD diagnosis is still unclear due to the instability and inaccurate measurements of plasma Aβ levels in the blood of patients with AD. If a consistent value of plasma Aβ from the blood can be obtained, this might help determine whether plasma Aβ is a potential biomarker for AD diagnosis. We predicted the brain amyloid deposit by measuring the plasma Aβ levels. This cross-sectional study included 353 participants (215 cognitively normal, 79 with mild cognitive impairment, and 59 with AD dementia) who underwent Pittsburgh-compound B positron emission tomography (PiB-PET) scans. We treated a mixture of protease inhibitors and phosphatase inhibitors (MPP) and detected plasma Aβ42 and Aβ40 (MPP-Aβ42 and MPP-Aβ40) in a stable manner using xMAP technology. MPP-Aβ40 and MPP-Aβ42/40 (MPP-Aβs) were significantly different between subjects with positive amyloid deposition (PiB+) and those with negative amyloid deposition (PiB-) (P < 0.0001). Furthermore, MPP-Aβ40 (P < 0.0001, r = 0.23) and MPP-Aβ42/40 ratio (P < 0.0001, r = -0.23) showed significant correlation with global PiB deposition (standardized uptake value ratio). In addition, our integrated multivariable (MPP-Aβ42/40, gender, age, and apolipoprotein E genotypes) logistic regression model proposes a new standard for the prediction of cerebral amyloid deposition. MPP-Aβ might be one of the potential blood biomarkers for the prediction of PiB-PET positivity in the brain.

Function algorithms for MPP scientific subroutines, volume 1

NASA Technical Reports Server (NTRS)

Gouch, J. G.

1984-01-01

Design documentation and user documentation for function algorithms for the Massively Parallel Processor (MPP) are presented. The contract specifies development of MPP assembler instructions to perform the following functions: natural logarithm; exponential (e to the x power); square root; sine; cosine; and arctangent. To fulfill the requirements of the contract, parallel array and solar implementations for these functions were developed on the PDP11/34 Program Development and Management Unit (PDMU) that is resident at the MPP testbed installation located at the NASA Goddard facility.

A quantitative approach to developing Parkinsonian monkeys (Macaca fascicularis) with intracerebroventricular 1-methyl-4-phenylpyridinium injections.

PubMed

Li, Hao; Lei, Xiaoguang; Huang, Baihui; Rizak, Joshua D; Yang, Lichuan; Yang, Shangchuan; Wu, Jing; Lü, Longbao; Wang, Jianhong; Yan, Ting; Li, Hongwei; Wang, Zhengbo; Hu, Yingzhou; Le, Weidong; Deng, Xingli; Li, Jiali; Xu, Lin; Zhang, Baorong; Hu, Xintian

2015-08-15

Non-human primate Parkinson's disease (PD) models are essential for PD research. The most extensively used PD monkey models are induced with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). However, the modeling processes of developing PD monkeys cannot be quantitatively controlled with MPTP. Therefore, a new approach to quantitatively develop chronic PD monkey models will help to advance the goals of "reduction, replacement and refinement" in animal experiments. A novel chronic PD monkey models was reported using the intracerebroventricular administration of 1-methyl-4-phenylpyridinium (MPP(+)) in Cynomolgus monkeys (Macaca fascicularis). This approach successfully produced stable and consistent PD monkeys with typical motor symptoms and pathological changes. More importantly, a sigmoidal relationship (Y=8.15801e(-0.245/x); R=0.73) was discovered between PD score (Y) and cumulative dose of MPP(+) (X). This relationship was then used to develop two additional PD monkeys under a specific time schedule (4 weeks), with planned PD scores (7) by controlling the dose and frequency of the MPP(+) administration as an independent validation of the formula. We developed Parkinsonian monkeys within controlled time frames by regulating the accumulated dose of MPP(+) intracerebroventricular administered, while limiting side effects often witnessed in models developed with the peripheral administration of MPTP, makes this model highly suitable for treatment development. This novel approach provides an edge in evaluating the mechanisms of PD pathology associated with environmental toxins and novel treatment approaches as the formula developed provides a "map" to control and predict the modeling processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Evidence for hydroxyl radical scavenging action of nitric oxide donors in the protection against 1-methyl-4-phenylpyridinium-induced neurotoxicity in rats.

PubMed

Banerjee, Rebecca; Saravanan, Karuppagounder S; Thomas, Bobby; Sindhu, Kizhake M; Mohanakumar, Kochupurackal P

2008-06-01

In the present study we provide evidence for hydroxyl radical (*OH) scavenging action of nitric oxide (NO*), and subsequent dopaminergic neuroprotection in a hemiparkinsonian rat model. Reactive oxygen species are strongly implicated in the nigrostriatal dopaminergic neurotoxicity caused by the parkinsonian neurotoxin, 1-methyl-4-phenylpyridinium (MPP+). Since the role of this free radical as a neurotoxicant or neuroprotectant is debatable, we investigated the effects of some of the NO* donors such as S-nitroso-N-acetylpenicillamine (SNAP), 3-morpholinosydnonimine hydrochloride (SIN-1), sodium nitroprusside (SNP) and nitroglycerin (NG) on in vitro *OH generation in a Fenton-like reaction involving ferrous citrate, as well as in MPP+-induced *OH production in the mitochondria. We also tested whether co-administration of NO* donor and MPP+ could protect against MPP+-induced dopaminergic neurotoxicity in rats. While NG, SNAP and SIN-1 attenuated MPP+-induced *OH generation in the mitochondria, and in a Fenton-like reaction, SNP caused up to 18-fold increase in *OH production in the latter reaction. Striatal dopaminergic depletion following intranigral infusion of MPP+ in rats was significantly attenuated by NG, SNAP and SIN-1, but not by SNP. Solutions of NG, SNAP and SIN-1, exposed to air for 48 h to remove NO*, when administered similarly failed to attenuate MPP+-induced neurotoxicity in vivo. Conversely, long-time air-exposed SNP solution when administered in rats intranigrally, caused a dose-dependent depletion of the striatal dopamine. These results confirm the involvement of *OH in the nigrostriatal degeneration caused by MPP+, indicate the *OH scavenging ability of NO*, and demonstrate protection by NO* donors against MPP+-induced dopaminergic neurotoxicity in rats.

Nanoparticles that do not adhere to mucus provide uniform and long-lasting drug delivery to airways following inhalation

PubMed Central

Schneider, Craig S.; Xu, Qingguo; Boylan, Nicholas J.; Chisholm, Jane; Tang, Benjamin C.; Schuster, Benjamin S.; Henning, Andreas; Ensign, Laura M.; Lee, Ethan; Adstamongkonkul, Pichet; Simons, Brian W.; Wang, Sho-Yu S.; Gong, Xiaoqun; Yu, Tao; Boyle, Michael P.; Suk, Jung Soo; Hanes, Justin

2017-01-01

Mucoadhesive particles (MAP) have been widely explored for pulmonary drug delivery because of their perceived benefits in improving particle residence in the lungs. However, retention of particles adhesively trapped in airway mucus may be limited by physiologic mucus clearance mechanisms. In contrast, particles that avoid mucoadhesion and have diameters smaller than mucus mesh spacings rapidly penetrate mucus layers [mucus-penetrating particles (MPP)], which we hypothesized would provide prolonged lung retention compared to MAP. We compared in vivo behaviors of variously sized, polystyrene-based MAP and MPP in the lungs following inhalation. MAP, regardless of particle size, were aggregated and poorly distributed throughout the airways, leading to rapid clearance from the lungs. Conversely, MPP as large as 300 nm exhibited uniform distribution and markedly enhanced retention compared to size-matched MAP. On the basis of these findings, we formulated biodegradable MPP (b-MPP) with an average diameter of <300 nm and examined their behavior following inhalation relative to similarly sized biodegradable MAP (b-MAP). Although b-MPP diffused rapidly through human airway mucus ex vivo, b-MAP did not. Rapid b-MPP movements in mucus ex vivo correlated to a more uniform distribution within the airways and enhanced lung retention time as compared to b-MAP. Furthermore, inhalation of b-MPP loaded with dexamethasone sodium phosphate (DP) significantly reduced inflammation in a mouse model of acute lung inflammation compared to both carrier-free DP and DP-loaded MAP. These studies provide a careful head-to-head comparison of MAP versus MPP following inhalation and challenge a long-standing dogma that favored the use of MAP for pulmonary drug delivery. PMID:28435870

Processing, stability, and kinetic parameters of C5a peptidase from Streptococcus pyogenes.

PubMed

Anderson, Elizabeth T; Wetherell, Michael G; Winter, Laurie A; Olmsted, Stephen B; Cleary, Patrick P; Matsuka, Yury V

2002-10-01

A recombinant streptococcal C5a peptidase was expressed in Escherichia coli and its catalytic properties and thermal stability were subjected to examination. It was shown that the NH2-terminal region of C5a peptidase (Asn32-Asp79/Lys90) forms the pro-sequence segment. Upon maturation the propeptide is hydrolyzed either via an autocatalytic intramolecular cleavage or by exogenous protease streptopain. At pH 7.4 the enzyme exhibited maximum activity in the narrow range of temperatures between 40 and 43 degrees C. The process of heat denaturation of C5a peptidase investigated by fluorescence and circular dichroism spectroscopy revealed that the protein undergoes biphasic unfolding transition with Tm of 50 and 70 degrees C suggesting melting of different parts of the molecule with different stability. Unfolding of the less stable structures was accompanied by the loss of proteolytic activity. Using synthetic peptides corresponding to the COOH-terminus of human complement C5a we demonstrated that in vitro peptidase catalyzes hydrolysis of two His67-Lys68 and Ala58-Ser59 peptide bonds. The high catalytic efficiency obtained for the SQLRANISHKDMQLGR extended peptide compared to the poor hydrolysis of its derivative Ac-SQLRANISH-pNA that lacks residues at P2'-P7' positions, suggest the importance of C5a peptidase interactions with the P' side of the substrate.

Progressive alterations in multipotent hematopoietic progenitors underlie lymphoid cell loss in aging.

PubMed

Young, Kira; Borikar, Sneha; Bell, Rebecca; Kuffler, Lauren; Philip, Vivek; Trowbridge, Jennifer J

2016-10-17

Declining immune function with age is associated with reduced lymphoid output of hematopoietic stem cells (HSCs). Currently, there is poor understanding of changes with age in the heterogeneous multipotent progenitor (MPP) cell compartment, which is long lived and responsible for dynamically regulating output of mature hematopoietic cells. In this study, we observe an early and progressive loss of lymphoid-primed MPP cells (LMPP/MPP4) with aging, concomitant with expansion of HSCs. Transcriptome and in vitro functional analyses at the single-cell level reveal a concurrent increase in cycling of aging LMPP/MPP4 with loss of lymphoid priming and differentiation potential. Impaired lymphoid differentiation potential of aged LMPP/MPP4 is not rescued by transplantation into a young bone marrow microenvironment, demonstrating cell-autonomous changes in the MPP compartment with aging. These results pinpoint an age and cellular compartment to focus further interrogation of the drivers of lymphoid cell loss with aging. © 2016 Young et al.

MPP1 directly interacts with flotillins in erythrocyte membrane - Possible mechanism of raft domain formation.

PubMed

Biernatowska, Agnieszka; Augoff, Katarzyna; Podkalicka, Joanna; Tabaczar, Sabina; Gajdzik-Nowak, Weronika; Czogalla, Aleksander; Sikorski, Aleksander F

2017-11-01

Flotillins are prominent, oligomeric protein components of erythrocyte (RBC) membrane raft domains and are considered to play an important structural role in lateral organization of the plasma membrane. In our previous work on erythroid membranes and giant plasma membrane vesicles (GPMVs) derived from them we have shown that formation of functional domains (resting state rafts) depends on the presence of membrane palmitoylated protein 1 (MPP1/p55), pointing to its new physiological role. Exploration of the molecular mechanism of MPP1 function in organizing membrane domains described here, through searching for its molecular partners in RBC membrane by using different methods, led to the identification of the raft-marker proteins, flotillin 1 and flotillin 2, as hitherto unreported direct MPP1 binding-partners in the RBC membrane. These proteins are found in high molecular-weight complexes in native RBC membrane and, significantly, their presence was shown to be separate from the well-known protein 4.1-dependent interactions of MPP1 with membrane proteins. Furthermore, FLIM analysis revealed that loss of the endogenous MPP1-flotillins interactions resulted in significant changes in RBC membrane-fluidity, emphasizing the physiological importance of such interactions in vivo. Therefore, our data establish a new perspective on the role of MPP1 in erythroid cells and suggests that direct MPP1-flotillins interactions could be the major driving-force behind the formation of raft domains in RBC. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Tripeptidyl Peptidase II Mediates Levels of Nuclear Phosphorylated ERK1 and ERK2.

PubMed

Wiemhoefer, Anne; Stargardt, Anita; van der Linden, Wouter A; Renner, Maria C; van Kesteren, Ronald E; Stap, Jan; Raspe, Marcel A; Tomkinson, Birgitta; Kessels, Helmut W; Ovaa, Huib; Overkleeft, Herman S; Florea, Bogdan; Reits, Eric A

2015-08-01

Tripeptidyl peptidase II (TPP2) is a serine peptidase involved in various biological processes, including antigen processing, cell growth, DNA repair, and neuropeptide mediated signaling. The underlying mechanisms of how a peptidase can influence this multitude of processes still remain unknown. We identified rapid proteomic changes in neuroblastoma cells following selective TPP2 inhibition using the known reversible inhibitor butabindide, as well as a new, more potent, and irreversible peptide phosphonate inhibitor. Our data show that TPP2 inhibition indirectly but rapidly decreases the levels of active, di-phosphorylated extracellular signal-regulated kinase 1 (ERK1) and ERK2 in the nucleus, thereby down-regulating signal transduction downstream of growth factors and mitogenic stimuli. We conclude that TPP2 mediates many important cellular functions by controlling ERK1 and ERK2 phosphorylation. For instance, we show that TPP2 inhibition of neurons in the hippocampus leads to an excessive strengthening of synapses, indicating that TPP2 activity is crucial for normal brain function. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

The distinguishing signature of magnetic Penrose process

NASA Astrophysics Data System (ADS)

Dadhich, Naresh; Tursunov, Arman; Ahmedov, Bobomurat; Stuchlík, Zdeněk

2018-07-01

In this Letter, we wish to point out that the distinguishing feature of magnetic Penrose process (MPP) is its super high-efficiency exceeding 100 per cent (which was established in mid 1980s for discrete particle accretion) of extraction of rotational energy of a rotating black hole electromagnetically for a magnetic field of milli Gauss order. Another similar process, which is also driven by the electromagnetic field, is Blandford-Znajek mechanism (BZ) that could be envisaged as high magnetic field limit MPP as it requires threshold magnetic field of order 104 G. Recent simulation studies of fully relativistic magnetohydrodynamic (MHD) flows have borne out super high-efficiency signature of the process for high magnetic field regime; viz BZ. We would like to make a clear prediction that similar simulation studies of MHD flows for low magnetic field regime, where BZ would be inoperative, would also have superefficiency.

Effects of blue light on pigment biosynthesis of Monascus.

PubMed

Chen, Di; Xue, Chunmao; Chen, Mianhua; Wu, Shufen; Li, Zhenjing; Wang, Changlu

2016-04-01

The influence of different illumination levels of blue light on the growth and intracellular pigment yields of Monascus strain M9 was investigated. Compared with darkness, constant exposure to blue light of 100 lux reduced the yields of six pigments, namely, rubropunctatamine (RUM), monascorubramine (MOM), rubropunctatin (RUN), monascorubrin (MON), monascin (MS), and ankaflavin (AK). However, exposure to varying levels of blue light had different effects on pigment production. Exposure to 100 lux of blue light once for 30 min/day and to 100 lux of blue light once and twice for 15 min/day could enhance RUM, MOM, MS, and AK production and reduce RUN and MON compared with non-exposure. Exposure to 100 lux twice for 30 min/day and to 200 lux once for 45 min/day decreased the RUM, MOM, MS, and AK yields and increased the RUN and MON. Meanwhile, the expression levels of pigment biosynthetic genes were analyzed by real-time quantitative PCR. Results indicated that gene MpPKS5, mppR1, mppA, mppB, mmpC, mppD, MpFasA, MpFasB, and mppF were positively correlated with the yields of RUN and MON, whereas mppE and mppR2 were associated with RUM, MOM, MS, and AK production.

Projected savings through public health voluntary licences of HIV drugs negotiated by the Medicines Patent Pool (MPP).

PubMed

Juneja, Sandeep; Gupta, Aastha; Moon, Suerie; Resch, Stephen

2017-01-01

The Medicines Patent Pool (MPP) was established in 2010 to ensure timely access to low-cost generic versions of patented antiretroviral (ARV) medicines in low- and middle-income countries (LMICs) through the negotiation of voluntary licences with patent holders. While robust data on the savings generated by MPP and other major global public health initiatives is important, it is also difficult to quantify. In this study, we estimate the savings generated by licences negotiated by the MPP for ARV medicines to treat HIV/AIDS in LMICs for the period 2010-2028 and generate a cost-benefit ratio-based on people living with HIV (PLHIVs) in any new countries which gain access to an ARV due to MPP licences and the price differential between originator's tiered price and generics price, within the period where that ARV is patented. We found that the direct savings generated by the MPP are estimated to be USD 2.3 billion (net present value) by 2028, representing an estimated cost-benefit ratio of 1:43, which means for every USD 1 spent on MPP, the global public health community saves USD 43. The saving of USD 2.3 billion is equivalent to more than 24 million PLHIV receiving first-line ART in LMICs for 1 year at average prices today.

Cyclophilin B protects SH-SY5Y human neuroblastoma cells against MPP(+)-induced neurotoxicity via JNK pathway.

PubMed

Oh, Yoojung; Jeong, Kwon; Kim, Kiyoon; Lee, Young-Seok; Jeong, Suyun; Kim, Sung Soo; Yoon, Kyung-Sik; Ha, Joohun; Kang, Insug; Choe, Wonchae

2016-09-23

Parkinson's disease (PD) is the second most common neurodegenerative disorder of aging. PD involves a progressive loss of dopaminergic neurons in the substantia nigra pars compacta. 1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyidine (MPTP) and its toxic metabolite 1-methyl-4-phenylpyridinium ion (MPP+) inhibit the complex I of the mitochondrial electron transport chain, and have been widely used to construct PD models. Cyclophilin B (CypB) is an endoplasmic reticulum protein that binds to cyclosporine A as a cyclophilin family member. CypB has peptidyl-prolyl cis-trans isomerase (PPIase) activity. We investigated the protective effects of overexpressed CypB on MPP+-induced neurocytotoxicity in SH-SY5Y human neuroblastoma cells. Overexpressed CypB decreased MPP(+)-induced oxidative stress through the modulation of antioxidant enzymes including manganese superoxide dismutase and catalase, and prevented neurocytotoxicity via mitogen-activated protein kinase, especially the c-Jun N-terminal kinase pathway. In addition, CypB inhibited the activation of MPP(+)-induced the pro-apoptotic molecules poly (ADP-ribose) polymerase, Bax, and Bcl-2, and attenuated MPP(+)-induced mitochondrial dysfunction. The data suggest that overexpressed CypB protects neuronal cells from MPP+-induced dopaminergic neuronal cell death. Copyright © 2016 Elsevier Inc. All rights reserved.

Neuroprotective effects of three different sizes nanochelating based nano complexes in MPP(+) induced neurotoxicity.

PubMed

Maghsoudi, Amirhossein; Fakharzadeh, Saideh; Hafizi, Maryam; Abbasi, Maryam; Kohram, Fatemeh; Sardab, Shima; Tahzibi, Abbas; Kalanaky, Somayeh; Nazaran, Mohammad Hassan

2015-03-01

Parkinson's disease (PD) is the world's second most common dementia, which the drugs available for its treatment have not had effects beyond slowing the disease process. Recently nanotechnology has induced the chance for designing and manufacturing new medicines for neurodegenerative disease. It is demonstrated that by tuning the size of a nanoparticle, the physiological effect of the nanoparticle can be controlled. Using novel nanochelating technology, three nano complexes: Pas (150 nm), Paf (100 nm) and Pac (40 nm) were designed and in the present study their neuroprotective effects were evaluated in PC12 cells treated with 1-methyl-4-phenyl-pyridine ion (MPP (+)). PC12 cells were pre-treated with the Pas, Paf or Pac nano complexes, then they were subjected to 10 μM MPP (+). Subsequently, cell viability, intracellular free Calcium and reactive oxygen species (ROS) levels, mitochondrial membrane potential, catalase (CAT) and superoxide dismutase (SOD) activity, Glutathione (GSH) and malondialdehyde (MDA) levels and Caspase 3 expression were evaluated. All three nano complexes, especially Pac, were able to increase cell viability, SOD and CAT activity, decreased Caspase 3 expression and prevented the generation of ROS and the loss of mitochondrial membrane potential caused by MPP(+). Pre-treatment with Pac and Paf nano complexes lead to a decrease of intracellular free Calcium, but Pas nano complex could not decrease it. Only Pac nano complex decreased MDA levels and other nano complexes could not change this parameter compared to MPP(+) treated cells. Hence according to the results, all nanochelating based nano complexes induced neuroprotective effects in an experimental model of PD, but the smallest nano complex, Pac, showed the best results.

The precipitation of magnesium potassium phosphate hexahydrate for P and K recovery from synthetic urine.

PubMed

Xu, Kangning; Li, Jiyun; Zheng, Min; Zhang, Chi; Xie, Tao; Wang, Chengwen

2015-09-01

Nutrients recovery from urine to close the nutrient loop is one of the most attractive benefits of source separation in wastewater management. The current study presents an investigation of the thermodynamic modeling of the recovery of P and K from synthetic urine via the precipitation of magnesium potassium phosphate hexahydrate (MPP). Experimental results show that maximum recovery efficiencies of P and K reached 99% and 33%, respectively, when the precipitation process was initiated only through adding dissolvable Mg compound source. pH level and molar ratio of Mg:P were key factors determining the nutrient recovery efficiencies. Precipitation equilibrium of MPP and magnesium sodium phosphate heptahydrate (MSP) was confirmed via precipitates analysis using a Scanning Electron Microscope/Energy Dispersive Spectrometer and an X-ray Diffractometer. Then, the standard solubility products of MPP and MSP in the synthetic urine were estimated to be 10(-12.2 ± 0.0.253) and 10(-11.6 ± 0.253), respectively. The thermodynamic model formulated on chemical software PHREEQC could well fit the experimental results via comparing the simulated and measured concentrations of K and P in equilibrium. Precipitation potentials of three struvite-type compounds were calculated through thermodynamic modeling. Magnesium ammonium phosphate hexahydrate (MAP) has a much higher tendency to precipitate than MPP and MSP in normal urine while MSP was the main inhibitor of MPP in ammonium-removed urine. To optimize the K recovery, ammonium should be removed prior as much as possible and an alternative alkaline compound should be explored for pH adjustment rather than NaOH. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation in vitro and in vivo of curcumin-loaded mPEG-PLA/TPGS mixed micelles for oral administration.

PubMed

Duan, Yuwei; Zhang, Baomei; Chu, Lianjun; Tong, Henry Hy; Liu, Weidong; Zhai, Guangxi

2016-05-01

The aim of this work is to prepare and characterize curcumin-loaded methoxy poly(ethylene glycol)-poly(lactide) (mPEG-PLA)/D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) mixed micelles (CUR-MPP-TPGS-MMs), analyze the influence of formulation on enhancing the solubility of curcumin in water, and evaluate the improvement of intestinal absorption after oral administration. CUR-MPP-TPGS-MMs were prepared using the thin film diffusion method and optimized with the uniform design. The optimal CUR-MPP-TPGS-MMs were provided with high drug-loading (16.1%), small size (46.0 nm) and spherical shape. Low critical micelle concentration (CMC) and superior dilution stability showed that CUR-MPP-TPGS-MMs could keep integrity during the dilution of gastrointestinal fluid. In vitro drug release study indicated a sustained release of curcumin from CUR-MPP-TPGS-MMs in simulated gastrointestinal solution. The absorption mechanism of passive diffusion was obtained by measuring in situ intestinal absorption of CUR-MPP-TPGS-MMs in rats, and the best absorption segment was found to be the duodenum. The pharmacokinetics was evaluated in rats at the dose of 75 mg/kg by intragastric administration. The Cmax and mean retention time (MRT0-24) for CUR-MPP-TPGS-MMs were both increased, and the relative bioavailability of micelle formulation to curcumin suspension was 927.3%. These results suggested that mPEG-PLA/TPGS mixed micelle system (MPP-TPGS-MMs) showed great potential in improving oral bioavailability of curcumin. Copyright © 2016 Elsevier B.V. All rights reserved.

Bragg peak prediction from quantitative proton computed tomography using different path estimates

PubMed Central

Wang, Dongxu; Mackie, T Rockwell

2015-01-01

This paper characterizes the performance of the straight-line path (SLP) and cubic spline path (CSP) as path estimates used in reconstruction of proton computed tomography (pCT). The GEANT4 Monte Carlo simulation toolkit is employed to simulate the imaging phantom and proton projections. SLP, CSP and the most-probable path (MPP) are constructed based on the entrance and exit information of each proton. The physical deviations of SLP, CSP and MPP from the real path are calculated. Using a conditional proton path probability map, the relative probability of SLP, CSP and MPP are calculated and compared. The depth dose and Bragg peak are predicted on the pCT images reconstructed using SLP, CSP, and MPP and compared with the simulation result. The root-mean-square physical deviations and the cumulative distribution of the physical deviations show that the performance of CSP is comparable to MPP while SLP is slightly inferior. About 90% of the SLP pixels and 99% of the CSP pixels lie in the 99% relative probability envelope of the MPP. Even at an imaging dose of ~0.1 mGy the proton Bragg peak for a given incoming energy can be predicted on the pCT image reconstructed using SLP, CSP, or MPP with 1 mm accuracy. This study shows that SLP and CSP, like MPP, are adequate path estimates for pCT reconstruction, and therefore can be chosen as the path estimation method for pCT reconstruction, which can aid the treatment planning and range prediction of proton radiation therapy. PMID:21212472

76 FR 72736 - Self-Regulatory Organizations; Financial Industry Regulatory Authority, Inc.; Order Granting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-25

... the migration to the MPP.\\15\\ In connection with these communications, FINRA noted that, although subject to Commission approval of the proposed rule change, FINRA anticipates that the MPP migration would... requested that the MPP migration and the proposed rule changes be implemented not earlier than the end of...

The language parallel Pascal and other aspects of the massively parallel processor

NASA Technical Reports Server (NTRS)

Reeves, A. P.; Bruner, J. D.

1982-01-01

A high level language for the Massively Parallel Processor (MPP) was designed. This language, called Parallel Pascal, is described in detail. A description of the language design, a description of the intermediate language, Parallel P-Code, and details for the MPP implementation are included. Formal descriptions of Parallel Pascal and Parallel P-Code are given. A compiler was developed which converts programs in Parallel Pascal into the intermediate Parallel P-Code language. The code generator to complete the compiler for the MPP is being developed independently. A Parallel Pascal to Pascal translator was also developed. The architecture design for a VLSI version of the MPP was completed with a description of fault tolerant interconnection networks. The memory arrangement aspects of the MPP are discussed and a survey of other high level languages is given.

Application of edible coating with starch and carvacrol in minimally processed pumpkin.

PubMed

Santos, Adriele R; da Silva, Alex F; Amaral, Viviane C S; Ribeiro, Alessandra B; de Abreu Filho, Benicio A; Mikcha, Jane M G

2016-04-01

The present study evaluated the effect of an edible coating of cassava starch and carvacrol in minimally processed pumpkin (MPP). The minimal inhibitory concentration (MIC) of carvacrol against Escherichia coli, Salmonella enterica serotype Typhimurium, Aeromonas hydrophila, and Staphylococcus aureus was determined. The edible coating that contained carvacrol at the MIC and 2 × MIC was applied to MPP, and effects were evaluated with regard to the survival of experimentally inoculated bacteria and autochthonous microflora in MPP. Total titratable acidity, pH, weight loss, and soluble solids over 7 days of storage under refrigeration was also analyzed. MIC of carvacrol was 312 μg/ml. Carvacrol at the MIC reduced the counts of E. coli and S. Typhimurium by approximately 5 log CFU/g. A. hydrophila was reduced by approximately 8 log CFU/g, and S. aureus was reduced by approximately 2 log CFU/g on the seventh day of storage. Carvacrol at the 2 × MIC completely inhibited all isolates on the first day of Storage. coliforms at 35 °C and 45 °C were not detected (< 3 MPN/g) with either treatment on all days of shelf life. The treatment groups exhibited a reduction of approximately 2 log CFU/g in psychrotrophic counts compared with controls on the last day of storage. Yeast and mold were not detected with either treatment over the same period. The addition of carvacrol did not affect total titratable acidity, pH, or soluble solids and improved weight loss. The edible coating of cassava starch with carvacrol may be an interesting approach to improve the safety and microbiological quality of MPP.

Climate Change, Population Immunity, and Hyperendemicity in the Transmission Threshold of Dengue

PubMed Central

Oki, Mika; Yamamoto, Taro

2012-01-01

Background It has been suggested that the probability of dengue epidemics could increase because of climate change. The probability of epidemics is most commonly evaluated by the basic reproductive number (R0), and in mosquito-borne diseases, mosquito density (the number of female mosquitoes per person [MPP]) is the critical determinant of the R0 value. In dengue-endemic areas, 4 different serotypes of dengue virus coexist–a state known as hyperendemicity–and a certain proportion of the population is immune to one or more of these serotypes. Nevertheless, these factors are not included in the calculation of R0. We aimed to investigate the effects of temperature change, population immunity, and hyperendemicity on the threshold MPP that triggers an epidemic. Methods and Findings We designed a mathematical model of dengue transmission dynamics. An epidemic was defined as a 10% increase in seroprevalence in a year, and the MPP that triggered an epidemic was defined as the threshold MPP. Simulations were conducted in Singapore based on the recorded temperatures from 1980 to 2009 The threshold MPP was estimated with the effect of (1) temperature only; (2) temperature and fluctuation of population immunity; and (3) temperature, fluctuation of immunity, and hyperendemicity. When only the effect of temperature was considered, the threshold MPP was estimated to be 0.53 in the 1980s and 0.46 in the 2000s, a decrease of 13.2%. When the fluctuation of population immunity and hyperendemicity were considered in the model, the threshold MPP decreased by 38.7%, from 0.93 to 0.57, from the 1980s to the 2000s. Conclusions The threshold MPP was underestimated if population immunity was not considered and overestimated if hyperendemicity was not included in the simulations. In addition to temperature, these factors are particularly important when quantifying the threshold MPP for the purpose of setting goals for vector control in dengue-endemic areas. PMID:23144746

Climate change, population immunity, and hyperendemicity in the transmission threshold of dengue.

PubMed

Oki, Mika; Yamamoto, Taro

2012-01-01

It has been suggested that the probability of dengue epidemics could increase because of climate change. The probability of epidemics is most commonly evaluated by the basic reproductive number (R(0)), and in mosquito-borne diseases, mosquito density (the number of female mosquitoes per person [MPP]) is the critical determinant of the R(0) value. In dengue-endemic areas, 4 different serotypes of dengue virus coexist-a state known as hyperendemicity-and a certain proportion of the population is immune to one or more of these serotypes. Nevertheless, these factors are not included in the calculation of R(0). We aimed to investigate the effects of temperature change, population immunity, and hyperendemicity on the threshold MPP that triggers an epidemic. We designed a mathematical model of dengue transmission dynamics. An epidemic was defined as a 10% increase in seroprevalence in a year, and the MPP that triggered an epidemic was defined as the threshold MPP. Simulations were conducted in Singapore based on the recorded temperatures from 1980 to 2009 The threshold MPP was estimated with the effect of (1) temperature only; (2) temperature and fluctuation of population immunity; and (3) temperature, fluctuation of immunity, and hyperendemicity. When only the effect of temperature was considered, the threshold MPP was estimated to be 0.53 in the 1980s and 0.46 in the 2000s, a decrease of 13.2%. When the fluctuation of population immunity and hyperendemicity were considered in the model, the threshold MPP decreased by 38.7%, from 0.93 to 0.57, from the 1980s to the 2000s. The threshold MPP was underestimated if population immunity was not considered and overestimated if hyperendemicity was not included in the simulations. In addition to temperature, these factors are particularly important when quantifying the threshold MPP for the purpose of setting goals for vector control in dengue-endemic areas.

IGF-1 protects SH-SY5Y cells against MPP+-induced apoptosis via PI3K/PDK-1/Akt pathway.

PubMed

Kim, Chanyang; Park, Seungjoon

2018-03-01

Insulin-like growth factor (IGF)-1 is a well-known anti-apoptotic pro-survival factor and phosphatidylinositol-3-kinase (PI3K)/Akt pathway is linked to cell survival induced by IGF-1. It is also reported that Akt signaling is modulated by 3-phosphoinositide-dependent kinase-1 (PDK1). In the current study, we investigated whether the anti-apoptotic effect of IGF-1 in SH-SY5Y cells exposed to 1-methyl-4-phenylpyridinium (MPP + ) is associated with the activity of PI3K/PDK1/Akt pathway. Treatment of cells with IGF-1 inhibited MPP + -induced apoptotic cell death. IGF-1-induced activation of Akt and the protective effect of IGF-1 on MPP + -induced apoptosis were abolished by chemical inhibition of PDK1 (GSK2334470) or PI3K (LY294002). The phosphorylated levels of Akt and PDK1 were significantly suppressed after MPP + exposure, while IGF-1 treatment completely restored MPP+-induced reductions in phosphorylation. IGF-1 protected cells from MPP + insult by suppressing intracellular reactive oxygen species (ROS) production and malondialdehyde levels and increasing superoxide dismutase activity. Mitochondrial ROS levels were also increased during MPP + exposure, which were attenuated by IGF-1 treatment. In addition, IGF-1-treated cells showed increased activities of succinate dehydrogenase and citrate synthase, stabilization of mitochondrial transmembrane potential, increased ratio of Bcl-2 to Bax, prevention of cytochrome c release and inhibition of caspase-3 activation with PARP cleavage. Furthermore, the protective effects of IGF-1 on oxidative stress and mitochondrial dysfunction were attenuated when cells were preincubated with GSK2334470 or LY294002. Our data suggest that IGF-1 protects SH-SY5Y cells against MPP + -associated oxidative stress by preserving mitochondrial integrity and inhibiting mitochondrial apoptotic cascades via the activation of PI3K/PDK1/Akt pathway. © 2018 The authors.

IGF-1 protects SH-SY5Y cells against MPP+-induced apoptosis via PI3K/PDK-1/Akt pathway

PubMed Central

Kim, Chanyang; Park, Seungjoon

2018-01-01

Insulin-like growth factor (IGF)-1 is a well-known anti-apoptotic pro-survival factor and phosphatidylinositol-3-kinase (PI3K)/Akt pathway is linked to cell survival induced by IGF-1. It is also reported that Akt signaling is modulated by 3-phosphoinositide-dependent kinase-1 (PDK1). In the current study, we investigated whether the anti-apoptotic effect of IGF-1 in SH-SY5Y cells exposed to 1-methyl-4-phenylpyridinium (MPP+) is associated with the activity of PI3K/PDK1/Akt pathway. Treatment of cells with IGF-1 inhibited MPP+-induced apoptotic cell death. IGF-1-induced activation of Akt and the protective effect of IGF-1 on MPP+-induced apoptosis were abolished by chemical inhibition of PDK1 (GSK2334470) or PI3K (LY294002). The phosphorylated levels of Akt and PDK1 were significantly suppressed after MPP+ exposure, while IGF-1 treatment completely restored MPP+-induced reductions in phosphorylation. IGF-1 protected cells from MPP+ insult by suppressing intracellular reactive oxygen species (ROS) production and malondialdehyde levels and increasing superoxide dismutase activity. Mitochondrial ROS levels were also increased during MPP+ exposure, which were attenuated by IGF-1 treatment. In addition, IGF-1-treated cells showed increased activities of succinate dehydrogenase and citrate synthase, stabilization of mitochondrial transmembrane potential, increased ratio of Bcl-2 to Bax, prevention of cytochrome c release and inhibition of caspase-3 activation with PARP cleavage. Furthermore, the protective effects of IGF-1 on oxidative stress and mitochondrial dysfunction were attenuated when cells were preincubated with GSK2334470 or LY294002. Our data suggest that IGF-1 protects SH-SY5Y cells against MPP+-associated oxidative stress by preserving mitochondrial integrity and inhibiting mitochondrial apoptotic cascades via the activation of PI3K/PDK1/Akt pathway. PMID:29459421

A maximum power point tracking algorithm for photovoltaic applications

NASA Astrophysics Data System (ADS)

Nelatury, Sudarshan R.; Gray, Robert

2013-05-01

The voltage and current characteristic of a photovoltaic (PV) cell is highly nonlinear and operating a PV cell for maximum power transfer has been a challenge for a long time. Several techniques have been proposed to estimate and track the maximum power point (MPP) in order to improve the overall efficiency of a PV panel. A strategic use of the mean value theorem permits obtaining an analytical expression for a point that lies in a close neighborhood of the true MPP. But hitherto, an exact solution in closed form for the MPP is not published. This problem can be formulated analytically as a constrained optimization, which can be solved using the Lagrange method. This method results in a system of simultaneous nonlinear equations. Solving them directly is quite difficult. However, we can employ a recursive algorithm to yield a reasonably good solution. In graphical terms, suppose the voltage current characteristic and the constant power contours are plotted on the same voltage current plane, the point of tangency between the device characteristic and the constant power contours is the sought for MPP. It is subject to change with the incident irradiation and temperature and hence the algorithm that attempts to maintain the MPP should be adaptive in nature and is supposed to have fast convergence and the least misadjustment. There are two parts in its implementation. First, one needs to estimate the MPP. The second task is to have a DC-DC converter to match the given load to the MPP thus obtained. Availability of power electronics circuits made it possible to design efficient converters. In this paper although we do not show the results from a real circuit, we use MATLAB to obtain the MPP and a buck-boost converter to match the load. Under varying conditions of load resistance and irradiance we demonstrate MPP tracking in case of a commercially available solar panel MSX-60. The power electronics circuit is simulated by PSIM software.

Peripheral Administration of Tetanus Toxin Hc Fragment Prevents MPP+ Toxicity In Vivo.

PubMed

Moreno-Galarza, Natalia; Mendieta, Liliana; Palafox-Sánchez, Victoria; Herrando-Grabulosa, Mireia; Gil, Carles; Limón, Daniel I; Aguilera, José

2018-02-19

Several studies have shown that intrastriatal application of 1-methyl-4-phenylpyridinium (MPP + ) produces similar biochemical changes in rat to those seen in Parkinson's disease (PD), such as dopaminergic terminal degeneration and consequent appearance of motor deficits, making the MPP + lesion a widely used model of parkinsonism in rodents. Previous results from our group have shown a neuroprotective effect of the carboxyl-terminal domain of the heavy chain of tetanus toxin (Hc-TeTx) under different types of stress. In the present study, pretreatment with the intraperitoneal injection of Hc-TeTx in rats prevents the decrease of tyrosine hydroxylase immunoreactivity in the striatum due to injury with MPP + , when applied stereotaxically in the striatum. Similarly, striatal catecholamine contents are restored, as well as the levels of two other dopaminergic markers, the dopamine transporter (DAT) and the vesicular monoamine transporter-2 (VMAT-2). Additionally, uptake studies of [ 3 H]-dopamine and [ 3 H]-MPP + reveal that DAT action is not affected by Hc-TeTx, discarding a protective effect due to a reduced entry of MPP + into nerve terminals. Behavioral assessments show that Hc-TeTx pretreatment improves the motor skills (amphetamine-induced rotation, forelimb use, and adjusting steps) of MPP + -treated rats. Our results lead us to consider Hc-TeTx as a potential therapeutic tool in pathologies caused by impairment of dopaminergic innervation in the striatum, as is the case of PD.

Projected savings through public health voluntary licences of HIV drugs negotiated by the Medicines Patent Pool (MPP)

PubMed Central

Juneja, Sandeep; Gupta, Aastha; Moon, Suerie; Resch, Stephen

2017-01-01

The Medicines Patent Pool (MPP) was established in 2010 to ensure timely access to low-cost generic versions of patented antiretroviral (ARV) medicines in low- and middle-income countries (LMICs) through the negotiation of voluntary licences with patent holders. While robust data on the savings generated by MPP and other major global public health initiatives is important, it is also difficult to quantify. In this study, we estimate the savings generated by licences negotiated by the MPP for ARV medicines to treat HIV/AIDS in LMICs for the period 2010–2028 and generate a cost-benefit ratio–based on people living with HIV (PLHIVs) in any new countries which gain access to an ARV due to MPP licences and the price differential between originator’s tiered price and generics price, within the period where that ARV is patented. We found that the direct savings generated by the MPP are estimated to be USD 2.3 billion (net present value) by 2028, representing an estimated cost-benefit ratio of 1:43, which means for every USD 1 spent on MPP, the global public health community saves USD 43. The saving of USD 2.3 billion is equivalent to more than 24 million PLHIV receiving first-line ART in LMICs for 1 year at average prices today. PMID:28542239

Neural nets on the MPP

NASA Technical Reports Server (NTRS)

Hastings, Harold M.; Waner, Stefan

1987-01-01

The Massively Parallel Processor (MPP) is an ideal machine for computer experiments with simulated neural nets as well as more general cellular automata. Experiments using the MPP with a formal model neural network are described. The results on problem mapping and computational efficiency apply equally well to the neural nets of Hopfield, Hinton et al., and Geman and Geman.

MPP+ induces necrostatin-1- and ferrostatin-1-sensitive necrotic death of neuronal SH-SY5Y cells.

PubMed

Ito, Keisuke; Eguchi, Yutaka; Imagawa, Yusuke; Akai, Shuji; Mochizuki, Hideki; Tsujimoto, Yoshihide

2017-01-01

Regulation of cell death is potentially a powerful treatment modality for intractable diseases such as neurodegenerative diseases. Although there have been many reports about the possible involvement of various types of cell death in neurodegenerative diseases, it is still unclear exactly how neurons die in patients with these diseases, thus treatment strategies based on cell death regulation have not been established yet. To obtain some insight into the mechanisms of cell death involved in neurodegenerative diseases, we studied the effect of 1-methyl-4-phenylpyridinium (MPP+) on the human neuroblastoma cell line SH-SY5Y (a widely used model of Parkinson's disease). We found that MPP+ predominantly induced non-apoptotic death of neuronally differentiated SH-SY5Y cells. This cell death was strongly inhibited by necrostatin-1 (Nec-1), a necroptosis inhibitor, and by an indole-containing compound (3,3'-diindolylmethane: DIM). However, it occurred independently of receptor-interacting serine/threonine-protein kinase 1/3 (RIP1/RIP3), indicating that this form of cell death was not necroptosis. MPP+-induced cell death was also inhibited by several inhibitors of ferroptosis, including ferrostatin-1 (Fer-1). Although MPP+-induced death and ferroptosis shared some features, such as occurrence of lipid peroxidation and inhibition by Fer-1, MPP+-induced death seemed to be distinct from ferroptosis because MPP+-induced death (but not ferroptosis) was inhibited by Nec-1, was independent of p53, and was accompanied by ATP depletion and mitochondrial swelling. Further investigation of MPP+-induced non-apoptotic cell death may be useful for understanding the mechanisms of neuronal loss and for treatment of neurodegenerative diseases such as Parkinson's disease.

MPP+ induces necrostatin-1- and ferrostatin-1-sensitive necrotic death of neuronal SH-SY5Y cells

PubMed Central

Ito, Keisuke; Eguchi, Yutaka; Imagawa, Yusuke; Akai, Shuji; Mochizuki, Hideki; Tsujimoto, Yoshihide

2017-01-01

Regulation of cell death is potentially a powerful treatment modality for intractable diseases such as neurodegenerative diseases. Although there have been many reports about the possible involvement of various types of cell death in neurodegenerative diseases, it is still unclear exactly how neurons die in patients with these diseases, thus treatment strategies based on cell death regulation have not been established yet. To obtain some insight into the mechanisms of cell death involved in neurodegenerative diseases, we studied the effect of 1-methyl-4-phenylpyridinium (MPP+) on the human neuroblastoma cell line SH-SY5Y (a widely used model of Parkinson’s disease). We found that MPP+ predominantly induced non-apoptotic death of neuronally differentiated SH-SY5Y cells. This cell death was strongly inhibited by necrostatin-1 (Nec-1), a necroptosis inhibitor, and by an indole-containing compound (3,3′-diindolylmethane: DIM). However, it occurred independently of receptor-interacting serine/threonine-protein kinase 1/3 (RIP1/RIP3), indicating that this form of cell death was not necroptosis. MPP+-induced cell death was also inhibited by several inhibitors of ferroptosis, including ferrostatin-1 (Fer-1). Although MPP+-induced death and ferroptosis shared some features, such as occurrence of lipid peroxidation and inhibition by Fer-1, MPP+-induced death seemed to be distinct from ferroptosis because MPP+-induced death (but not ferroptosis) was inhibited by Nec-1, was independent of p53, and was accompanied by ATP depletion and mitochondrial swelling. Further investigation of MPP+-induced non-apoptotic cell death may be useful for understanding the mechanisms of neuronal loss and for treatment of neurodegenerative diseases such as Parkinson’s disease. PMID:28250973

Substance P prevents 1-methyl-4-phenylpyridinium-induced cytotoxicity through inhibition of apoptosis via neurokinin-1 receptors in MES23.5 cells.

PubMed

Wang, Shuang-Yan; Chen, Lei; Xue, Yan; Xia, Yu-Jun

2015-12-01

[Sar9, Met(O2)11] termed Substance P (SP), is an effective and selective agonist for the neurokinin‑1 (NK‑1) receptors, which are synthetic peptides, similar in structure to SP. SP is an important neurotransmitter or neuromodulator mediated by neurokinin receptors, namely the SP receptor in the central nervous system. The excitatory effects induced by SP may be selectively inhibited by a neurokinin‑1 receptor antagonist, such as SR140333B. It has been proposed that Parkinson's disease (PD) is primarily caused by the loss of trophic peptidergic neurotransmitter, possibly SP, which may lead to the degeneration of neurons. In previous studies, 1‑methyl‑4‑phenylpyridinium (MPP+) has been frequently utilized to establish animal or cell models of PD. In the present study, to further investigate the effects of SP in PD, MPP+ was employed to investigate the promising anti‑apoptotic effects of SP, and examine the underlying mechanisms of the pathology in the MES23.5 dopaminergic cell line. The results indicated that MPP+‑triggered apoptosis was prevented by treatment with SP. SP treatment also decreased the MPP+‑triggered Ca2+ influx, caspase‑3 re‑activity, reactive oxygen species production and mitochondrial membrane potential decrease. Treatment with MPP+ also induced phosphorylation of c‑Jun N‑terminal kinase and p38 mitogen‑activated protein kinase. In addition, treatment with SP inhibited the MPP+‑triggered neurotoxicity in MES23.5 cells. However, no changes were observed in SR140333B+SP+MPP+‑treated MES23.5 cell lines. In conclusion, SP could protect the cells from MPP+‑induced cytotoxicity by inhibiting the apoptosis via NK-1 receptors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshikatsu, Yuki; Ishida, Yo-ichi; Sudo, Haruka

Nuclear VCP-like 2 (NVL2) is a member of the chaperone-like AAA-ATPase family and is involved in the biosynthesis of 60S ribosomal subunits in mammalian cells. We previously showed the interaction of NVL2 with a DExD/H-box RNA helicase MTR4/DOB1, which is a known cofactor for an exoribonuclease complex, the exosome. This finding implicated NVL2 in RNA metabolic processes during ribosome biogenesis. In the present study, we found that a series of mutations within the ATPase domain of NVL2 causes a defect in pre-rRNA processing into mature 28S and 5.8S rRNAs. Co-immunoprecipitation analysis showed that NVL2 was associated with the nuclear exosomemore » complex, which includes RRP6 as a nucleus-specific catalytic subunit. This interaction was prevented by depleting either MTR4 or RRP6, indicating their essential role in mediating this interaction with NVL2. Additionally, knockdown of MPP6, another cofactor for the nuclear exosome, also prevented the interaction by causing MTR4 to dissociate from the nuclear exosome. These results suggest that NVL2 is involved in pre-rRNA processing by associating with the nuclear exosome complex and that MPP6 is required for maintaining the integrity of this rRNA processing complex. - Highlights: • ATPase-deficient mutants of NVL2 have decreased pre-rRNA processing. • NVL2 associates with the nuclear exosome through interactions with MTR4 and RRP6. • MPP6 stabilizes MTR4-RRP6 interaction and allows NVL2 to interact with the complex.« less

Profiling of proteolytic enzymes in the gut of the tick Ixodes ricinus reveals an evolutionarily conserved network of aspartic and cysteine peptidases

PubMed Central

Sojka, Daniel; Franta, Zdeněk; Horn, Martin; Hajdušek, Ondřej; Caffrey, Conor R; Mareš, Michael; Kopáček, Petr

2008-01-01

Background Ticks are vectors for a variety of viral, bacterial and parasitic diseases in human and domestic animals. To survive and reproduce ticks feed on host blood, yet our understanding of the intestinal proteolytic machinery used to derive absorbable nutrients from the blood meal is poor. Intestinal digestive processes are limiting factors for pathogen transmission since the tick gut presents the primary site of infection. Moreover, digestive enzymes may find practical application as anti-tick vaccine targets. Results Using the hard tick, Ixodes ricinus, we performed a functional activity scan of the peptidase complement in gut tissue extracts that demonstrated the presence of five types of peptidases of the cysteine and aspartic classes. We followed up with genetic screens of gut-derived cDNA to identify and clone genes encoding the cysteine peptidases cathepsins B, L and C, an asparaginyl endopeptidase (legumain), and the aspartic peptidase, cathepsin D. By RT-PCR, expression of asparaginyl endopeptidase and cathepsins B and D was restricted to gut tissue and to those developmental stages feeding on blood. Conclusion Overall, our results demonstrate the presence of a network of cysteine and aspartic peptidases that conceivably operates to digest host blood proteins in a concerted manner. Significantly, the peptidase components of this digestive network are orthologous to those described in other parasites, including nematodes and flatworms. Accordingly, the present data and those available for other tick species support the notion of an evolutionary conservation of a cysteine/aspartic peptidase system for digestion that includes ticks, but differs from that of insects relying on serine peptidases. PMID:18348719

Edaravone protected PC12 cells against MPP(+)-cytoxicity via inhibiting oxidative stress and up-regulating heme oxygenase-1 expression.

PubMed

Cheng, Baohua; Guo, Yunliang; Li, Chuangang; Ji, Bingyuan; Pan, Yanyou; Chen, Jing; Bai, Bo

2014-08-15

Oxidative stress is involved in the pathogenesis of Parkinson's disease (PD). Edaravone has been shown to have a neuroprotective effect. In the present work, we investigated the effect of edaravone on 1-methyl-4-phenylpyridinium (MPP(+))-treated PC12 cells. Edaravone inhibited the decrease of cell viability and apoptosis induced by MPP(+) in PC12 cells. In addition, edaravone alleviated intracellular reactive oxygen species (ROS) production. MPP(+) induced heme oxygenase-1 (HO-1) expression, which was further enhanced by edaravone. The inhibitor of HO-1 zinc protoporphyrin-IX attenuated the neuroprotection of edaravone. So edaravone protected PC12 cells against MPP(+)-cytoxicity via inhibiting oxidative stress and up-regulating HO-1 expression. The data showed that edaravone was neuroprotective and could be potentially therapeutics for PD in future. Copyright © 2014 Elsevier B.V. All rights reserved.

Sound absorption of a finite micro-perforated panel backed by a shunted loudspeaker.

PubMed

Tao, Jiancheng; Jing, Ruixiang; Qiu, Xiaojun

2014-01-01

Deep back cavities are usually required for micro-perforated panel (MPP) constructions to achieve good low frequency absorption. To overcome the problem, a close-box loudspeaker with a shunted circuit is proposed to substitute the back wall of the cavity of the MPP constructions to constitute a composite absorber. Based on the equivalent circuit model, the acoustic impedance of the shunted loudspeaker is formulated first, then a prediction model of the sound absorption of the MPP backed by shunted loudspeaker is developed by employing the mode solution of a finite size MPP coupled by an air cavity with an impendence back wall. The MPP absorbs mid to high frequency sound, and with properly adjusted electrical parameters of its shunted circuit, the shunted loudspeaker absorbs low frequency sound, so the composite absorber provides a compact solution to broadband sound control. Numerical simulations and experiments are carried out to validate the model.

Simultaneous recovery of phosphorus and potassium as magnesium potassium phosphate from synthetic sewage sludge effluent.

PubMed

Nakao, Satoshi; Nishio, Takayuki; Kanjo, Yoshinori

2017-10-01

Bench-scale experiments were performed to investigate simultaneous recovery of phosphorus and potassium from synthetic sewage sludge effluent as crystals of magnesium potassium phosphate (MPP or struvite-(K), MgKPO 4 ·6H 2 O). The optimal pH of MPP formation was 11.5. A phosphorus level of at least 3 mM and K:P molar ratio over 3 were necessary to form MPP, which showed higher content rate of phosphorus and potassium in precipitate. MPP crystallization was confirmed by analysing the precipitates using a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) apparatus and an X-ray Diffractometer (XRD). Inhibition of MPP crystallization by iron and aluminium was confirmed by precipitation experiments and SEM-EDX analysis. Potassium ratio against magnesium in precipitate decreased for iron concentrations greater than over 0.2 mM and aluminium concentrations over 0.05 mM.

Processing of two latent membrane protein 1 MHC class I epitopes requires tripeptidyl peptidase II involvement.

PubMed

Diekmann, Jan; Adamopoulou, Eleni; Beck, Olaf; Rauser, Georg; Lurati, Sarah; Tenzer, Stefan; Einsele, Hermann; Rammensee, Hans-Georg; Schild, Hansjörg; Topp, Max S

2009-08-01

The EBV Ag latent membrane protein 1 (LMP1) has been described as a potential target for T cell immunotherapy in EBV-related malignancies. However, only a few CD8(+) T cell epitopes are known, and the benefit of LMP1-specific T cell immunotherapy has not yet been proven. In this work, we studied the processing of the two LMP1 HLA-A02-restricted epitopes, YLLEMLRWL and YLQQNWWTL. We found that target cells endogenously expressing the native LMP1 are not recognized by CTLs specific for these epitopes because the N-terminal part of LMP1 limits the efficiency of epitope generation. We further observed that the proteasome is not required for the generation of both epitopes and that the YLLEMLRWL epitope seems to be destroyed by the proteasome, because blocking of proteasomal activities enhanced specific CTL activation. Activation of LMP1-specific CTLs could be significantly reduced after inhibition of the tripeptidyl peptidase II, suggesting a role for this peptidase in the processing of both epitopes. Taken together, our results demonstrate that the MHC class I-restricted LMP1 epitopes studied in this work are two of very few epitopes known to date to be processed proteasome independently by tripeptidyl peptidase II.

Altered peptidase activities in thyroid neoplasia and hyperplasia.

PubMed

Larrinaga, Gorka; Blanco, Lorena; Errarte, Peio; Beitia, Maider; Sanz, Begoña; Perez, Itxaro; Irazusta, Amaia; Sánchez, Clara E; Santaolalla, Francisco; Andrés, Leire; López, José I

2013-01-01

Papillary thyroid carcinoma (PTC), follicular thyroid adenoma (FTA), and thyroid nodular hyperplasia (TNH) are the most frequent diseases of the thyroid gland. Previous studies described the involvement of dipeptidyl-peptidase IV (DPPIV/CD26) in the development of thyroid neoplasia and proposed it as an additional tool in the diagnosis/prognosis of these diseases. However, very little is known about the involvement of other peptidases in neoplastic and hyperplastic processes of this gland. The catalytic activity of 10 peptidases in a series of 30 PTC, 10 FTA, and 14 TNH was measured fluorimetrically in tumour and nontumour adjacent tissues. The activity of DPPIV/CD26 was markedly higher in PTC than in FTA, TNH, and nontumour tissues. Aspartyl aminopeptidase (AspAP), alanyl aminopeptidase (AlaAP), prolyl endopeptidase, pyroglutamyl peptidase I, and aminopeptidase B activities were significantly increased in thyroid neoplasms when compared to nontumour tissues. AspAP and AlaAP activities were also significantly higher in PTC than in FTA and TNH. These data suggest the involvement of DPPIV/CD26 and some cytosolic peptidases in the neoplastic development of PTC and FTA. Further studies will help to define the possible clinical usefulness of AlaAP and AspAP in the diagnosis/prognosis of thyroid neoplasms.

Design of a plasmonic micromotor for enhanced photo-remediation of polluted anaerobic stagnant waters.

PubMed

Zhang, Zhijun; Zhao, Andong; Wang, Faming; Ren, Jinsong; Qu, Xiaogang

2016-04-25

A motor plasmonic photocatalyst (MPP) is developed to promote photocatalysis in an anaerobic stagnant environment. The MPP is fabricated through the newly developed nano/micromotor fabrication method: template-assisted aqueous phase synthesis. With the help of H2O2 (fuel), the solar photocatalytic efficiency of the MPP can be enhanced more than 110 times.

The American Geological Institute Minority Participation Program

NASA Astrophysics Data System (ADS)

Smith, M. J.; Byerly, G. R.; Callahan, C. N.

2001-12-01

Since 1971, the American Geological Institute (AGI) Minority Participation Program (MPP) has supported scholarships for underrepresented minorities in the geosciences at the undergraduate and graduate levels. Some of our MPP scholars have gone on to hugely successful careers in the geosciences. MPP scholars include corporate leaders, university professors, a NASA scientist-astronaut and a National Science Foundation (NSF) CAREER awardee. Yet as ethnic minorities continue to be underrepresented in the geosciences, AGI plans to expand its efforts beyond its traditional undergraduate and graduate scholarships to include diversity programs for secondary school geoscience teacher internships, undergraduate research travel support, and doctoral research fellowships. Funding for the MPP has come from multiple sources, including industry, scientific societies, individuals, and during the last 10 years, the NSF. College-level students apply for the MPP awards or award renewals, and the MPP Advisory Committee selects scholarship recipients based upon student academic performance, financial need, and potential for success as a geoscience professional. Mentoring is a long-standing hallmark of the AGI MPP. Every AGI MPP scholar is assigned a professional geoscientist as a mentor. The mentor is responsible for regular personal contacts with MPP scholars. The MPP Advisory Committee aims to match the profession of the mentor with the scholar's academic interest. Throughout the year, mentors and scholars communicate about possible opportunities in the geosciences such as internships, participation in symposia, professional society meetings, and job openings. Mentors have also been active in helping younger students cope with the major changes involved in relocating to a new region of the country or a new college culture. We believe that AGI is well-positioned to advance diversity in the geosciences through its unique standing as the major professional organization in the geosciences. AGI maintains strong links to its 37 professional Member Societies, state and federal agencies, and funding programs, many with distinctive programs in the geoscience education. AGI Corporate Associates have consistently pledged to support diversity issues in geoscience education. Current plans include seeking funding for 48 undergraduate awards at 2500 each and 24,000 to support undergraduate travel to professional meetings. We also expect to increase the size of our graduate scholarship program to 30 students and raise an additional $30,000 to support graduate travel to professional meetings.

Mucus-penetrating nanoparticles for vaginal and gastrointestinal drug delivery

NASA Astrophysics Data System (ADS)

Ensign-Hodges, Laura

A method that could provide more uniform and longer-lasting drug delivery to mucosal surfaces holds the potential to greatly improve the effectiveness of prophylactic and therapeutic approaches for numerous diseases and conditions, including sexually transmitted infections and inflammatory bowel disease. However, the body's natural defenses, including adhesive, rapidly cleared mucus linings coating nearly all entry points to the body not covered by skin, has limited the effectiveness of drug and gene delivery by nanoscale delivery systems. Here, we investigate the use of muco-inert mucus-penetrating nanoparticles (MPP) for improving vaginal and gastrointestinal drug delivery. Conventional hydrophobic nanoparticles strongly adhere to mucus, facilitating rapid clearance from the body. Here, we demonstrate that mucoadhesive polystyrene nanoparticles (conventional nanoparticles, CP) become mucus-penetrating in human cervicovaginal mucus (CVM) after pretreatment with sufficient concentrations of Pluronic F127. Importantly, the diffusion rate of large MPP did not change in F127 pretreated CVM, implying there is no affect on the native pore structure of CVM. Additionally, there was no increase in inflammatory cytokine release in the vaginal tract of mice after daily application of 1% F127 for one week. Importantly, HSV virus remains adherent in F127-pretreated CVM. Mucosal epithelia use osmotic gradients for fluid absorption and secretion. We hypothesized that hypotonically-induced fluid uptake could be advantageous for rapidly delivering drugs through mucus to the vaginal epithelium. We evaluated hypotonic formulations for delivering water-soluble drugs and for drug delivery with MPP. Hypotonic formulations markedly increased the rate at which drugs and MPP reached the epithelial surface. Additionally, hypotonic formulations greatly enhanced drug and MPP delivery to the entire epithelial surface, including deep into the vaginal folds (rugae) that isotonic formulations failed to reach. However, hypotonic formulations caused free drugs to be drawn through the epithelium, reducing vaginal retention. In contrast, hypotonic formulations caused MPP to accumulate rapidly and uniformly on vaginal surfaces, ideally positioned for sustained drug delivery. Using a mouse model of vaginal genital herpes (HSV-2) infection, we found that hypotonic delivery of free drug led to improved immediate protection, but diminished longer-term protection. Minimally hypotonic formulations provided rapid and uniform delivery of MPP to the entire vaginal surface, thus enabling formulations with minimal risk of epithelial toxicity. We then describe an ex vivo method for characterizing particle transport on freshly excised mucosal tissues. By directly observing MPP transport on vaginal, gastrointestinal, and respiratory tissue, we were able to determine an innate difference in mucus mesh size at different anatomical locations. In addition, we were able to optimize particle size for gastrointestinal delivery in mice. As described here, there are numerous barriers to effective drug delivery in the gastrointestinal tract, including the mucus barrier. We go on to demonstrate that MPP can improve delivery in the gastrointestinal tract, both by rectal and oral administration. Finally, we describe the use of MPP for improving vaginal drug delivery. Incomplete drug coverage and short duration of action limit the effectiveness of vaginally administered drugs, including microbicides for preventing sexually transmitted infections. We show that MPP provide uniform distribution over the vaginal epithelium, whereas CP are aggregated by mouse vaginal mucus, leading to poor distribution. By penetrating into the deepest mucus layers in the rugae, more MPP were retained in the vaginal tract compared to CP. After 24 h, when delivered in a conventional vaginal gel, patches of a model drug remained on the vaginal epithelium, whereas the epithelium was coated with drug delivered by MPP. We then demonstrate that when administered 30 min prior to inoculum, anti-HSV-2 MPP protected 53% of mice compared to only 16% protected by soluble drug. Overall, MPP improved vaginal drug distribution and retention, provided more effective protection against vaginal viral challenge than soluble drug, and were non-toxic when administered daily for one week.

Enhanced vaginal drug delivery through the use of hypotonic formulations that induce fluid uptake

PubMed Central

Ensign, Laura M.; Hoen, Timothy; Maisel, Katharina; Cone, Richard; Hanes, Justin

2013-01-01

Mucosal epithelia use osmotic gradients for fluid absorption and secretion. We hypothesized that administration of hypotonic solutions would induce fluid uptake that could be advantageous for rapidly delivering drugs through mucus to the vaginal epithelium. We found that hypotonic formulations markedly increased the rate at which small molecule drugs and muco-inert nanoparticles (mucus-penetrating particles, or MPP), but not conventional mucoadhesive nanparticles (CP), reached the vaginal epithelial surface in vivo in mice. Additionally, hypotonic formulations greatly enhanced drug and MPP delivery to the entire epithelial surface, including deep into the vaginal folds (rugae) that drugs or MPP in isotonic formulations failed to reach efficiently. However, hypotonic formulations caused unencapsulated “free” drugs to be drawn through the epithelium, reducing vaginal retention. In contrast, hypotonic formulations caused MPP to accumulate rapidly and uniformly on vaginal surfaces, ideally positioned for localized sustained drug delivery. Using a mouse model of vaginal genital herpes (HSV-2) infection, we found that hypotonic delivery of free drug led to improved immediate protection, but diminished longer-term protection. In contrast, as we previously demonstrated, hypotonic delivery of drug via MPP led to better long-term retention and protection in the vagina. Importantly, we demonstrate that slightly hypotonic formulations provided rapid and uniform delivery of MPP to the entire vaginal surface, thus enabling formulations with minimal risk of epithelial toxicity. Hypotonic formulations for vaginal drug delivery via MPP may significantly improve prevention and treatment of reproductive tract diseases and disorders. PMID:23769419

Cardiac resynchronization therapy by multipoint pacing improves response of left ventricular mechanics and fluid dynamics: a three-dimensional and particle image velocimetry echo study.

PubMed

Siciliano, Mariachiara; Migliore, Federico; Badano, Luigi; Bertaglia, Emanuele; Pedrizzetti, Gianni; Cavedon, Stefano; Zorzi, Alessandro; Corrado, Domenico; Iliceto, Sabino; Muraru, Denisa

2017-11-01

To characterize the effect of multipoint pacing (MPP) compared to biventricular pacing (BiV) on left ventricle (LV) mechanics and intraventricular fluid dynamics by three-dimensional echocardiography (3DE) and echocardiographic particle imaging velocimetry (Echo-PIV). In 11 consecutive patients [8 men; median age 65 years (57-75)] receiving cardiac resynchronization therapy (CRT) with a quadripolar LV lead (Quartet,St.Jude Medical,Inc.), 3DE and Echo-PIV data were collected for each pacing configuration (CRT-OFF, BiV, and MPP) at follow-up after 6 months. 3DE data included LV volumes, LV ejection fraction (LVEF), strain, and systolic dyssynchrony index (SDI). Echo-PIV was used to evaluate the directional distribution of global blood flow momentum, ranging from zero, when flow force is predominantly along the base-apex direction, up to 90° when it becomes transversal. MPP resulted in significant reduction in end-diastolic and end-systolic volumes compared with both CRT-OFF (P = 0.02; P = 0.008, respectively) and BiV (P = 0.04; P = 0.03, respectively). LVEF and cardiac output were significant superior in MPP compared with CRT-OFF, but similar between MPP and BiV. Statistical significant differences when comparing global longitudinal and circumferential strain and SDI with MPP vs. CRT-OFF were observed (P = 0.008; P = 0.008; P = 0.01, respectively). There was also a trend towards improvement in strain between BiV and MPP that did not reach statistical significance. MPP reflected into a significant reduction of the deviation of global blood flow momentum compared with both CRT-OFF and BiV (P = 0.002) indicating a systematic increase of longitudinal alignment from the base-apex orientation of the haemodynamic forces. These preliminary results suggest that MPP resulted in significant improvement of LV mechanics and fluid dynamics compared with BiV. However, larger studies are needed to confirm this hypothesis. © Crown copyright 2016.

Reducing retrogradation and lipid oxidation of normal and glutinous rice flours by adding mango peel powder.

PubMed

Siriamornpun, Sirithon; Tangkhawanit, Ekkarat; Kaewseejan, Niwat

2016-06-15

Green and ripe mango peel powders (MPP) were added to normal rice flour (NRF) and glutinous rice flour (GRF) at three levels (400, 800 and 1200 ppm) and their effects on physicochemical properties and lipid oxidation inhibition were investigated. Overall, MPP increased the breakdown viscosity and reduced the final viscosity in rice flours when compared to the control. Decreasing in retrogradation was observed in both NRF and GRF with MPP added of all levels. MPP addition also significantly inhibited the lipid oxidation of all flours during storage (30 days). Retrogradation values were strongly negatively correlated with total phenolic and flavonoid contents, but not with fiber content. The hydrogen bonds and hydrophilic interactions between phenolic compounds with amylopectin molecule may be involved the decrease of starch retrogradation, especially GRF. We suggest that the addition of MPP not only reduced the retrogradation but also inhibited the lipid oxidation of rice flour. Copyright © 2016 Elsevier Ltd. All rights reserved.

The human CLN2 protein/tripeptidyl-peptidase I is a serine protease that autoactivates at acidic pH.

PubMed

Lin, L; Sohar, I; Lackland, H; Lobel, P

2001-01-19

The CLN2 gene mutated in the fatal hereditary neurodegenerative disease late infantile neuronal ceroid lipofuscinosis encodes a lysosomal protease with tripeptidyl-peptidase I activity. To understand the enzymological properties of the protein, we purified and characterized C-terminal hexahistidine-tagged human CLN2p/tripeptidyl-peptidase I produced from insect cells transfected with a baculovirus vector. The N terminus of the secreted 66-kDa protein corresponds to residue 20 of the primary CLN2 gene translation product, indicating removal of a 19-residue signal peptide. The purified protein is enzymatically inactive; however, upon acidification, it is proteolytically processed and concomitantly acquires enzymatic activity. The N terminus of the final 46-kDa processed form (Leu196) corresponds to that of mature CLN2p/tripeptidyl-peptidase I purified from human brain. The activity of the mature enzyme is irreversibly inhibited by the serine esterase inhibitor diisopropyl fluorophosphate, which specifically and stoichiometrically reacts with CLN2p/tripeptidyl-peptidase I at Ser475, demonstrating that this residue represents the active site nucleophile. Expression of wild type and mutant proteins in CHO cells indicate that Ser475, Asp360, Asp517, but not His236 are essential for activity. These data indicate that the CLN2 gene product is synthesized as an inactive proenzyme that is autocatalytically converted to an active serine protease.

Silibinin pretreatment attenuates biochemical and behavioral changes induced by intrastriatal MPP+ injection in rats.

PubMed

Geed, Milind; Garabadu, Debapriya; Ahmad, Ausaf; Krishnamurthy, Sairam

2014-02-01

Silymarin commonly known for its hepatoprotective effect is reported to show protection against 6-hydroxydopamine-induced neurotoxicity. Silibinin forms the major active constituent of silymarin. Therefore, the neuroprotective effect of silibinin (50, 100 and 200 mg/kg) was evaluated in the unilaterally injected 1-methyl-4-phenylpyridinium (MPP(+))-induced dopaminergic neurotoxicity in male rats. A battery of tests such as elevated plus maze (EPM), narrow beam walk, open field, bar catalepsy, grip strength, and foot print analysis was performed to evaluate the behavioral symptoms of striatal dopaminergic toxicity. Furthermore, the mechanism of action of silibinin was investigated by evaluating the mitochondrial complex enzyme activities, mitochondrial integrity and oxidative status. Striatal caspase-3 and NFκB were expressed to evaluate the effect of silibinin on apoptosis and inflammation respectively. Silibinin (100 and 200 mg/kg) protected against MPP(+)-induced dopamine depletion in striatum. Silibinin reversed MPP(+)-induced decrease in transfer latency indicating memory consolidation in the EPM test. Silibinin (100 and 200 mg/kg) attenuated MPP(+)-induced motor deficits, such as fine motor movements and gait. MPP(+)-induced mitochondrial dysfunction, loss of integrity and oxidative stress were attenuated by silibinin. Silibinin decreased striatal caspase-3 and NFκB expression indicating potential anti-apoptotic and anti-inflammatory effects respectively. Hence, silibinin exhibited neuroprotective effect in the MPP(+) induced striatal toxicity augmenting dopamine levels. The mechanism of action may be linked to maintenance of mitochondrial bioenergetics and integrity apart from anti-apoptotic and anti-inflammatory activities. Copyright © 2013 Elsevier Inc. All rights reserved.

Inhibition of MPP+-induced mitochondrial damage and cell death by trifluoperazine and W-7 in PC12 cells.

PubMed

Lee, Chung Soo; Park, Se Young; Ko, Hyun Hee; Song, Jin Ho; Shin, Yong Kyoo; Han, Eun Sook

2005-01-01

Opening of the mitochondrial permeability transition pore has been recognized to be involved in cell death. The present study investigated the effect of trifluoperazine and W-7 on the MPP+-induced mitochondrial damage and cell death in undifferentiated PC12 cells. Calmodulin antagonists (trifluoperazine, W-7 and calmidazolium) at 0.5-1 microM significantly reduced the loss of cell viability in PC12 cells treated with 500 microM MPP+. Trifluoperazine and W-7 (0.5-1 microM) inhibited the nuclear damage, the loss of the mitochondrial transmembrane potential followed by cytochrome c release, and the elevation of intracellular Ca2+ levels due to MPP+ in PC12 cells and attenuated the formation of reactive oxygen species and the depletion of GSH. Calmodulin antagonists at 5-10 microM exhibited a cytotoxic effect on PC12 cells, and compounds at 10 microM did not attenuate cytotoxicity of MPP+. Calmodulin antagonists (0.5-1 microM) significantly reduced rotenone-induced mitochondrial damage and cell death, whereas they did not attenuate cell death and elevation of intracellular Ca2+ levels due to H2O2 or ionomycin. The results show that trifluoperazine and W-7 exhibit a differential inhibitory effect against cytotoxicity of MPP+ depending on concentration. Both compounds at the concentrations less than 5 microM may attenuate the MPP+-induced viability loss in PC12 cells by suppressing change in the mitochondrial membrane permeability and by lowering the intracellular Ca2+ levels.

Formulation of consumables management models. Volume 2: Mission planning processor user guide

NASA Technical Reports Server (NTRS)

Daly, J. K.; Torian, J. G.

1978-01-01

A user guide for the MPP (Mission Planning Processor) is presented. The MPP is used in the evaluation of particular missions, with appropriate display and storage of related consumables data. Design goals are accomplished by the use of an on-line/demand mode computer terminal Cathode Ray Tube Display. The process is such that the user merely adds specific mission/flight functions to a skeleton flight and/or alters the skeleton. The skeleton flight includes operational aspects from prelaunch through ground support equipment connect after rollout as required to place the STS (Space Transportation System) in a parking orbit, maintain the spacecraft and crew for the stated on-orbit period and return.

Aspartic Peptidases of Human Pathogenic Trypanosomatids: Perspectives and Trends for Chemotherapy

PubMed Central

Santos, L.O.; Garcia-Gomes, A.S.; Catanho, M.; Sodré, C.L.; Santos, A.L.S.; Branquinha, M.H.; d’Avila-Levy, C.M.

2013-01-01

Aspartic peptidases are proteolytic enzymes present in many organisms like vertebrates, plants, fungi, protozoa and in some retroviruses such as human immunodeficiency virus (HIV). These enzymes are involved in important metabolic processes in microorganisms/virus and play major roles in infectious diseases. Although few studies have been performed in order to identify and characterize aspartic peptidase in trypanosomatids, which include the etiologic agents of leishmaniasis, Chagas’ disease and sleeping sickness, some beneficial properties of aspartic peptidase inhibitors have been described on fundamental biological events of these pathogenic agents. In this context, aspartic peptidase inhibitors (PIs) used in the current chemotherapy against HIV (e.g., amprenavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir) were able to inhibit the aspartic peptidase activity produced by different species of Leishmania. Moreover, the treatment of Leishmania promastigotes with HIV PIs induced several perturbations on the parasite homeostasis, including loss of the motility and arrest of proliferation/growth. The HIV PIs also induced an increase in the level of reactive oxygen species and the appearance of irreversible morphological alterations, triggering parasite death pathways such as programed cell death (apoptosis) and uncontrolled autophagy. The blockage of physiological parasite events as well as the induction of death pathways culminated in its incapacity to adhere, survive and escape of phagocytic cells. Collectively, these results support the data showing that parasites treated with HIV PIs have a significant reduction in the ability to cause in vivo infection. Similarly, the treatment of Trypanosoma cruzi cells with pepstatin A showed a significant inhibition on both aspartic peptidase activity and growth as well as promoted several and irreversible morphological changes. These studies indicate that aspartic peptidases can be promising targets in trypanosomatid cells and aspartic proteolytic inhibitors can be benefic chemotherapeutic agents against these human pathogenic microorganisms. PMID:23298141

Contribution of exopeptidases to formation of nonprotein nitrogen during ensiling of alfalfa.

PubMed

Tao, L; Zhou, H; Guo, X S; Long, R J; Zhu, Y; Cheng, W

2011-08-01

The experiment was conducted to investigate the exopeptidase classes in alfalfa (Medicago sativa L.) leaves, and to determine their contribution to the formation of nonprotein nitrogen (NPN) components during ensiling. Six classes of inhibitors that included bestatin (aminopeptidase inhibitor), potato carboxypeptidase inhibitor (PCI, carboxypeptidase inhibitor), 1,10-phenanthroline (dipeptidase inhibitor), diprotin A (dipeptidyl-peptidase inhibitor), butabindide (tripeptidyl-peptidase inhibitor), and dipeptide Phe-Arg (peptidyl-dipeptidase inhibitor) were used. To determine the contribution of each exopeptidase to the formation of NPN products, aqueous extracts of fresh alfalfa were fermented to imitate the proteolytic process of ensiled alfalfa and to ensure that each class of exopeptidase inhibitor would have immediate contact with the proteases in the alfalfa extract. Five classes of exopeptidases; namely, aminopeptidase, carboxypeptidase, dipeptidase, dipeptidyl-peptidase, and tripeptidyl-peptidase, were shown to be present in alfalfa leaves, each playing a different role in alfalfa protein degradation. Aminopeptidase, carboxypeptidase, and dipeptidase were the main exopeptidases contributing to the formation of NH(3)-N. Among the 5 exopeptidases, tripeptidyl-peptidase appeared to be the principal exopeptidase in hydrolyzing forage protein into peptides, whereas carboxypeptidase and dipeptidase appeared to be more important in contributing to the formation of amino acid-N. Dipeptidyl-peptidase and tripeptidyl-peptidase did not play a role in the formation of NH(3)-N or amino acid-N. Dipeptidase, carboxypeptidase, and tripeptidyl-peptidase were the principal exopeptidases for hydrolyzing forage protein into NPN during ensilage, and treatment with a mixture of the 5 inhibitors reduced the total NPN concentration in the fermented alfalfa extract to about 45% of that in the control after 21 d of fermentation. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

On the simultaneous inversion of micro-perforated panels' parameters: Application to single and double air-cavity backed systems.

PubMed

Tayong, Rostand B; Manyo Manyo, Jacques A; Siryabe, Emmanuel; Ntamack, Guy E

2018-04-01

This study deals with the deduction of parameters of Micro-Perforated Panel (MPP) systems from impedance tube data. It is shown that there is an ambiguity problem that exists between the MPP thickness and its open area ratio. This problem makes it difficult to invert the reflection coefficient data fitting and therefore to deduct the MPP parameters. A technique is proposed to reduce this ambiguity by using an equation that links the hole diameter to the open area ratio. Reflection coefficient data obtained for two specimens with different characteristics is employed for searching the MPP parameters using a simulated annealing algorithm. The results obtained demonstrate the effectiveness of this technique.

Comment on "Effect of coal-fired power generation on visibility in a nearby National Park (Terhorst and Berkman, 2010)"

NASA Astrophysics Data System (ADS)

White, W. H.; Farber, R. J.; Malm, W. C.; Nuttall, M.; Pitchford, M. L.; Schichtel, B. A.

2012-08-01

Few electricity generating stations received more environmental scrutiny during the last quarter of the twentieth century than did the Mohave Power Project (MPP), a coal-fired facility near Grand Canyon National Park. Terhorst and Berkman (2010) examine regional aerosol monitoring data collected before and after the plant's 2006 retirement for retrospective evidence of MPP's impact on visibility in the Park. The authors' technical analysis is thoughtfully conceived and executed, but is misleadingly presented as discrediting previous studies and their interpretation by regulators. In reality the Terhorst-Berkman analysis validates a consensus on MPP's visibility impact that was established years before its closure, in a collaborative assessment undertaken jointly by Federal regulators and MPP's owners.

The American Geological Institute Minority Participation Program (MPP): Thirty Years of Improving Access to Opportunities in the Geosciences Through Undergraduate and Graduate Scholarships for Underrepresented Minorities

NASA Astrophysics Data System (ADS)

Callahan, C. N.; Byerly, G. R.; Smith, M. J.

2001-05-01

Since 1971, the American Geological Institute (AGI) Minority Participation Program (MPP) has supported scholarships for underrepresented minorities in the geosciences at the undergraduate and graduate levels. Some of our MPP scholars have gone on to hugely successful careers in the geosciences. MPP scholars include corporate leaders, university professors, a NASA scientist-astronaut and a National Science Foundation (NSF) CAREER awardee. Yet as ethnic minorities continue to be underrepresented in the geosciences, AGI plans to expand its efforts beyond its traditional undergraduate and graduate scholarships to include diversity programs for secondary school geoscience teacher internships, undergraduate research travel support, and doctoral research fellowships. AGI promotes its MPP efforts primarily through its web pages, which are very successful in attracting visitors; through its publications, especially Geotimes; and through its Corporate Associates and Member Societies. Funding for the MPP has come from multiple sources over the past 30 years. Industry, non-profit organizations, and individuals have been the primary source of funding for graduate scholarships. The NSF has regularly funded the undergraduate scholarships. AGI Corporate Associates have contributed to both scholarship programs. The MPP Advisory Committee selects scholarship recipients based upon student academic performance, financial need, and potential for success as a geoscience professional. AGI currently has 29 MPP scholars, including 11 undergraduate and 18 graduate students. Undergraduate scholarships range from \\1000 to \\5000, with an average award of approximately \\2500. Graduate scholarships range from \\500 to \\4000, with an average award of approximately \\1300. In addition to financial assistance, every MPP scholar is assigned a professional geoscientist as a mentor. The mentor is responsible for regular personal contacts with MPP scholars, and with writing evaluation reports that are used to gauge the needs of the scholar, and to access the success of the overall program. The MPP Advisory Committee aims to match the profession of the mentor with the scholar's academic interest. Throughout the year, mentors and scholars communicate about possible opportunities in the geosciences such as internships, participation in symposia, professional society meetings, and job openings. Mentors have also been active in helping younger students cope with the major changes involved in relocating to a new region of the country or a new college culture. We believe that AGI is well positioned to advance diversity in the geosciences through its unique standing as the major professional organization in the geosciences. AGI maintains strong links to its professional Member Societies, state and federal agencies and funding programs, many with distinctive programs in the geoscience education. AGI Corporate Associates have consistently pledged to support diversity issues in geoscience education. Current plans include seeking funding for 48 undergraduate awards at \\2500 each and \\24,000 to support undergraduate travel to professional meetings. We also expect to increase the size of our graduate scholarship program to 30 students and raise an additional \\$30,000 to support graduate travel to professional meetings.

Simulation of the MELiSSA closed loop system as a tool to define its integration strategy

NASA Astrophysics Data System (ADS)

Poughon, Laurent; Farges, Berangere; Dussap, Claude-Gilles; Godia, Francesc; Lasseur, Christophe

Inspired from a terrestrial ecosystem, MELiSSA (Micro Ecological Life Support System Alternative) is a project of closed life support system future long-term manned missions (Moon and Mars bases). Started on ESA in 1989, this 5 compartments concept has evolved following a mechanistic engineering approach for acquiring both theoretical and technical knowledge. In its current state of development the project can now start to demonstrate the MELiSSA loop concept at a pilot scale. Thus an integration strategy for a MELiSSA Pilot Plant (MPP) was defined, describing the different phases for tests and connections between compartments. The integration steps should be started in 2008 and be completed with a complete operational loop in 2015, which final objective is to achieve a closed liquid and gas loop with 100 Although the integration logic could start with the most advanced processes in terms of knowledge and hardware development, this logic needs to be completed by high politic of simulation. Thanks to this simulation exercise, the effective demonstrations of each independent process and its progressive coupling with others will be performed in operational conditions as close as possible to the final configuration. The theoretical approach described in this paper is based on mass balance models of each of the MELiSSA biological compartments which are used to simulate each integration step and the complete MPP loop itself. These simulations will help to identify criticalities of each integration steps and to check the consistencies between objectives, flows, recycling efficiencies and sizing of the pilot reactors. A MPP scenario compatible with the current knowledge of the operation of the pilot reactors was investigated and the theoretical performances of the system compared to the objectives of the MPP. From this scenario the most important milestone steps in the integration are highlighted and their behaviour can be simulated.

Multi-temporal surveys for microplastic particles enabled by a novel and fast application of SWIR imaging spectroscopy - Study of an urban watercourse traversing the city of Berlin, Germany.

PubMed

Schmidt, L Katharina; Bochow, Mathias; Imhof, Hannes K; Oswald, Sascha E

2018-08-01

Following the widespread assumption that a majority of ubiquitous marine microplastic particles originate from land-based sources, recent studies identify rivers as important pathways for microplastic particles (MPP) to the oceans. Yet a detailed understanding of the underlying processes and dominant sources is difficult to obtain with the existing accurate but extremely time-consuming methods available for the identification of MPP. Thus in the presented study, a novel approach applying short-wave infrared imaging spectroscopy for the quick and semi-automated identification of MPP is applied in combination with a multitemporal survey concept. Volume-reduced surface water samples were taken from transects at ten points along a major watercourse running through the South of Berlin, Germany, on six dates. After laboratory treatment, the samples were filtered onto glass fiber filters, scanned with an imaging spectrometer and analyzed by image processing. The presented method allows to count MPP, classify the plastic types and determine particle sizes. At the present stage of development particles larger than 450 μm in diameter can be identified and a visual validation showed that the results are reliable after a subsequent visual final check of certain typical error types. Therefore, the method has the potential to accelerate microplastic identification by complementing FTIR and Raman microspectroscopy. Technical advancements (e.g. new lens) will allow lower detection limits and a higher grade of automatization in the near future. The resulting microplastic concentrations in the water samples are discussed in a spatio-temporal context with respect to the influence (i) of urban areas, (ii) of effluents of three major Berlin wastewater treatment plants discharging into the canal and (iii) of precipitation events. Microplastic concentrations were higher downstream of the urban area and after precipitation. An increase in microplastic concentrations was discernible for the wastewater treatment plant located furthest upstream though not for the other two. Copyright © 2018 Elsevier Ltd. All rights reserved.

Impairment of Atg5-Dependent Autophagic Flux Promotes Paraquat- and MPP+-Induced Apoptosis But Not Rotenone or 6-Hydroxydopamine Toxicity

PubMed Central

Franco, Rodrigo

2013-01-01

Controversial reports on the role of autophagy as a survival or cell death mechanism in dopaminergic cell death induced by parkinsonian toxins exist. We investigated the alterations in autophagic flux and the role of autophagy protein 5 (Atg5)-dependent autophagy in dopaminergic cell death induced by parkinsonian toxins. Dopaminergic cell death induced by the mitochondrial complex I inhibitors 1-methyl-4-phenylpyridinium (MPP+) and rotenone, the pesticide paraquat, and the dopamine analog 6-hydroxydopamine (6-OHDA) was paralleled by increased autophagosome accumulation. However, when compared with basal autophagy levels using chloroquine, autophagosome accumulation was a result of impaired autophagic flux. Only 6-OHDA induced an increase in autophagosome formation. Overexpression of a dominant negative form of Atg5 increased paraquat- and MPP+-induced cell death. Stimulation of mammalian target of rapamycin (mTOR)-dependent signaling protected against cell death induced by paraquat, whereas MPP+-induced toxicity was enhanced by wortmannin, a phosphoinositide 3-kinase class III inhibitor, rapamycin, and trehalose, an mTOR-independent autophagy activator. Modulation of autophagy by either pharmacological or genetic approaches had no effect on rotenone or 6-OHDA toxicity. Cell death induced by parkinsonian neurotoxins was inhibited by the pan caspase inhibitor (Z-VAD), but only caspase-3 inhibition was able to decrease MPP+-induced cell death. Finally, inhibition of the lysosomal hydrolases, cathepsins, increased the toxicity by paraquat and MPP+, supporting a protective role of Atg5-dependent autophagy and lysosomes degradation pathways on dopaminegic cell death. These results demonstrate that in dopaminergic cells, Atg5-dependent autophagy acts as a protective mechanism during apoptotic cell death induced by paraquat and MPP+ but not during rotenone or 6-OHDA toxicity. PMID:23997112

Synthesis and Neuroprotective Action of Xyloketal Derivatives in Parkinson’s Disease Models

PubMed Central

Li, Shichang; Shen, Cunzhou; Guo, Wenyuan; Zhang, Xuefei; Liu, Shixin; Liang, Fengyin; Xu, Zhongliang; Pei, Zhong; Song, Huacan; Qiu, Liqin; Lin, Yongcheng; Pang, Jiyan

2013-01-01

Parkinson’s disease (PD) is the second most common neurodegenerative disease affecting people over age 55. Oxidative stress actively participates in the dopaminergic (DA) neuron degeneration of PD. Xyloketals are a series of natural compounds from marine mangrove fungus strain No. 2508 that have been reported to protect against neurotoxicity through their antioxidant properties. However, their protection versus 1-methyl-4-phenylpyridinium (MPP+)-induced neurotoxicity is only modest, and appropriate structural modifications are necessary to discover better candidates for treating PD. In this work, we designed and synthesized 39 novel xyloketal derivatives (1–39) in addition to the previously reported compound, xyloketal B. The neuroprotective activities of all 40 compounds were evaluated in vivo via respiratory burst assays and longevity-extending assays. During the zebrafish respiratory burst assay, compounds 1, 9, 23, 24, 36 and 39 strongly attenuated reactive oxygen species (ROS) generation at 50 μM. In the Caenorhabditis elegans longevity-extending assay, compounds 1, 8, 15, 16 and 36 significantly extended the survival rates (p < 0.005 vs. dimethyl sulfoxide (DMSO)). A total of 15 compounds were tested for the treatment of Parkinson’s disease using the MPP+-induced C. elegans model, and compounds 1 and 8 exhibited the highest activities (p < 0.005 vs. MPP+). In the MPP+-induced C57BL/6 mouse PD model, 40 mg/kg of 1 and 8 protected against MPP+-induced dopaminergic neurodegeneration and increased the number of DA neurons from 53% for the MPP+ group to 78% and 74%, respectively (p < 0.001 vs. MPP+ group). Thus, these derivatives are novel candidates for the treatment of PD. PMID:24351912

Sophora flavescens Aiton Decreases MPP+-Induced Mitochondrial Dysfunction in SH-SY5Y Cells

PubMed Central

Kim, Hee-Young; Jeon, Hyongjun; Kim, Hyungwoo; Koo, Sungtae; Kim, Seungtae

2018-01-01

Sophora flavescens Aiton (SF) has been used to treat various diseases including fever and inflammation in China, South Korea and Japan. Several recent reports have shown that SF has anti-inflammatory and anti-apoptotic effects, indicating that it is a promising candidate for treatment of Parkinson’s disease (PD). We evaluated the protective effect of SF against neurotoxin 1-methyl-4-phenylpyridinium ion (MPP+)-induced mitochondrial dysfunction in SH-SY5Y human neuroblastoma cells, an in vitro PD model. SH-SY5Y cells were incubated with SF for 24 h, after which they were treated with MPP+. MPP+-induced cytotoxicity and apoptosis were confirmed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling assay. MitoSOX red mitochondrial superoxide indicator, tetramethylrhodamine methyl ester perchlorate and Parkin, PTEN-induced putative kinase 1 (PINK1), and DJ-1 immunofluorescent staining were conducted to confirm the mitochondrial function. In addition, western blot was performed to evaluate apoptosis factors (Bcl-2, Bax, caspase-3 and cytochrome c) and mitochondrial function-related factors (Parkin, PINK1 and DJ-1). SF suppressed MPP+-induced cytotoxicity, apoptosis and collapse of mitochondrial membrane potential by inhibiting the increase of reactive oxidative species (ROS) and DNA fragmentation, and controlling Bcl-2, Bax, caspase-3 and cytochrome c expression. Moreover, it attenuated Parkin, PINK1 and DJ-1 expression from MPP+-induced decrease. SF effectively suppressed MPP+-induced cytotoxicity, apoptosis and mitochondrial dysfunction by regulating generation of ROS, disruption of mitochondrial membrane potential, mitochondria-dependent apoptosis and loss or mutation of mitochondria-related PD markers including Parkin, PINK1 and DJ-1. PMID:29740311

Sophora flavescens Aiton Decreases MPP+-Induced Mitochondrial Dysfunction in SH-SY5Y Cells.

PubMed

Kim, Hee-Young; Jeon, Hyongjun; Kim, Hyungwoo; Koo, Sungtae; Kim, Seungtae

2018-01-01

Sophora flavescens Aiton (SF) has been used to treat various diseases including fever and inflammation in China, South Korea and Japan. Several recent reports have shown that SF has anti-inflammatory and anti-apoptotic effects, indicating that it is a promising candidate for treatment of Parkinson's disease (PD). We evaluated the protective effect of SF against neurotoxin 1-methyl-4-phenylpyridinium ion (MPP + )-induced mitochondrial dysfunction in SH-SY5Y human neuroblastoma cells, an in vitro PD model. SH-SY5Y cells were incubated with SF for 24 h, after which they were treated with MPP + . MPP + -induced cytotoxicity and apoptosis were confirmed by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling assay. MitoSOX red mitochondrial superoxide indicator, tetramethylrhodamine methyl ester perchlorate and Parkin, PTEN-induced putative kinase 1 (PINK1), and DJ-1 immunofluorescent staining were conducted to confirm the mitochondrial function. In addition, western blot was performed to evaluate apoptosis factors (Bcl-2, Bax, caspase-3 and cytochrome c) and mitochondrial function-related factors (Parkin, PINK1 and DJ-1). SF suppressed MPP + -induced cytotoxicity, apoptosis and collapse of mitochondrial membrane potential by inhibiting the increase of reactive oxidative species (ROS) and DNA fragmentation, and controlling Bcl-2, Bax, caspase-3 and cytochrome c expression. Moreover, it attenuated Parkin, PINK1 and DJ-1 expression from MPP + -induced decrease. SF effectively suppressed MPP + -induced cytotoxicity, apoptosis and mitochondrial dysfunction by regulating generation of ROS, disruption of mitochondrial membrane potential, mitochondria-dependent apoptosis and loss or mutation of mitochondria-related PD markers including Parkin, PINK1 and DJ-1.

Essential Function of Protein 4.1G in Targeting of Membrane Protein Palmitoylated 6 into Schmidt-Lanterman Incisures in Myelinated Nerves

PubMed Central

Saitoh, Yurika; Ohno, Nobuhiko; Komada, Masayuki; Saitoh, Sei; Peles, Elior; Ohno, Shinichi

2012-01-01

Protein 4.1G is a membrane skeletal protein found in specific subcellular structures in myelinated Schwann cells and seminiferous tubules. Here, we show that in the mouse sciatic nerve, protein 4.1G colocalized at Schmidt-Lanterman incisures (SLI) and the paranodes with a member of the membrane-associated guanylate kinase (MAGUK) family, membrane protein palmitoylated 6 (MPP6). Coimmunoprecipitation experiments revealed that MPP6 was interacting with protein 4.1G. In contrast to wild-type nerves, in 4.1G knockout mice, MPP6 was found largely in the cytoplasm near Schwann cell nuclei, indicating an abnormal protein transport. Although the SLI remained in the 4.1G knockout sciatic nerves, as confirmed by E-cadherin immunostaining, their shape was altered in aged 4.1G knockout nerves compared to their shape in wild-type nerves. In the seminiferous tubules, MPP6 was localized similarly to protein 4.1G along cell membranes of the spermatogonium and early spermatocytes. However, in contrast to myelinated peripheral nerves, the specific localization of MPP6 in the seminiferous tubules was unaltered in the absence of protein 4.1G. These results indicate that 4.1G has a specific role in the targeting of MPP6 to the SLI and the assembly of these subcellular structures. PMID:22025680

Chrysotoxine, a novel bibenzyl compound selectively antagonizes MPP⁺, but not rotenone, neurotoxicity in dopaminergic SH-SY5Y cells.

PubMed

Song, Ju-Xian; Shaw, Pang-Chui; Wong, Ngok-Shun; Sze, Cho-Wing; Yao, Xin-Sheng; Tang, Chi-Wai; Tong, Yao; Zhang, Yan-Bo

2012-07-11

Chrysotoxine is a naturally occurring bibenzyl compound found in medicinal Dendrobium species. We previously reported that chrysotoxine structure-specifically suppressed 6-hydroxydopamine (6-OHDA)-induced dopaminergic cell death. Whether chrysotoxine and other structurally similar bibenzyl compounds could also inhibit the neurotoxicity of 1-methyl-4-phenyl pyridinium (MPP(+)) and rotenone has not been investigated. We showed herein that chrysotoxine inhibited MPP(+), but not rotenone, induced dopaminergic cell death in SH-SY5Y cells. The overproduction of reactive oxygen species (ROS), mitochondrial dysfunction as indexed by the decrease in membrane potential, increase in calcium concentration and NF-κB activation triggered by MPP(+) were blocked by chrysotoxine pretreatment. The imbalance between the pro-apoptotic signals (Bax, caspase-3, ERK and p38 MAPK) and the pro-survival signals (Akt/PI3K/GSK-3β) induced by MPP(+) was partially or totally rectified by chrysotoxine. The results indicated that ROS inhibition, mitochondria protection, NF-κB modulation and regulation of multiple signals determining cell survival and cell death were involved in the protective effects of chrysotoxine against MPP(+) toxicity in SH-SY5Y cells. Given the different toxic profiles of 6-OHDA and MPP(+) as compared to rotenone, our results also indicated that DAT inhibition may partially account for the neuroprotective effects of chrysotoxine. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Sound transmission through a microperforated-panel structure with subdivided air cavities.

PubMed

Toyoda, Masahiro; Takahashi, Daiji

2008-12-01

The absorption characteristics of a microperforated-panel (MPP) absorber have been widely investigated, and MPPs are recognized as a next-generation absorbing material due to their fiber-free nature and attractive appearance. Herein, further possibilities of MPPs are investigated theoretically from a sound transmission viewpoint. Employing an analytical model composed of a typical MPP and a back wall with an infinite extent, transmission loss through the structure is obtained. Although MPP structures generally have great potential for sound absorption, an improvement in the transmission loss at midfrequencies, which is important for architectural sound insulation, is not sufficient when using a backing cavity alone. Hence, to improve transmission loss at midfrequencies, an air-cavity-subdivision technique is applied to MPP structures. By subdividing the air cavity with partitions, each cell can create a local one-dimensional sound field as well as lead to a normal incidence into the apertures, which is the most effective condition for Helmholtz-type resonance absorption. Moreover, by providing the same motion as the back wall to the MPP, the sound-insulation performance can be further improved at midfrequencies.

Cold Shock Induced Protein RBM3 but Not Mild Hypothermia Protects Human SH-SY5Y Neuroblastoma Cells From MPP+-Induced Neurotoxicity.

PubMed

Yang, Hai-Jie; Shi, Xiang; Ju, Fei; Hao, Bei-Ning; Ma, Shuang-Ping; Wang, Lei; Cheng, Bin-Feng; Wang, Mian

2018-01-01

The cold shock protein RBM3 can mediate mild hypothermia-related protection in neurodegeneration such as Alzheimer's disease. However, it remains unclear whether RBM3 and mild hypothermia provide same protection in model of Parkinson's disease (PD), the second most common neurodegenerative disorder. In this study, human SH-SY5Y neuroblastoma cells subjected to insult by 1-methyl-4-phenylpyridinium (MPP + ) served as an in-vitro model of PD. Mild hypothermia (32°C) aggravated MPP + -induced apoptosis, which was boosted when RBM3 was silenced by siRNA. In contrast, overexpression of RBM3 significantly reduced this apoptosis. MPP + treatment downregulated the expression of RBM3 both endogenously and exogenously and suppressed its induction by mild hypothermia (32°C). In conclusion, our data suggest that cold shock protein RBM3 provides neuroprotection in a cell model of PD, suggesting that RBM3 induction may be a suitable strategy for PD therapy. However, mild hypothermia exacerbates MPP + -induced apoptosis even that RBM3 could be synthesized during mild hypothermia.

MPP+ analogs acting on mitochondria and inducing neuro-degeneration.

PubMed

Kotake, Y; Ohta, S

2003-12-01

This review focuses on the mechanisms of action and the injurious effect of complex I inhibitors, of which 1-methyl-4-phenylpyridinium ion (MPP(+)) is a well studied example. These compounds can be divided into two groups, i.e. competitive inhibitors with respect to ubiquinone, such as piericidine A, and non-competitive inhibitors such as rotenone. Complex I inhibitors such as MPP(+) have been reported to induce anatomical, behavioral, and biochemical changes similar to those seen in Parkinson's disease, which is characterized by nigrostriatal dopaminergic neuro-degeneration. Spectroscopic analyses and structure-activity relationship studies have indicated that the V-shaped structure of the rotenone molecule is critical for binding to the rotenone binding site on complex I. Many isoquinoline derivatives, some of them endogenous, are also complex I inhibitors. Many lines of evidence show that complex I inhibitors elicit neuronal cell death. Recently, it was reported that chronic and systemic exposure to low-dose rotenone reproduces the features of Parkinson's disease. This work further focused attention on compounds acting on mitochondria, such as MPP(+). In Guadeloupe, the French West Indies, patients with atypical parkinsonism or progressive supranuclear palsy are frequently encountered. These diseases seem to be associated with ingestion of tropical herbal teas or tropical fruits of the Annonaceae family, which contain complex I inhibitors such as benzylisoquinoline derivatives and acetogenins. Complex I inhibitors may not simply result in reactive oxygen species generation or ATP exhaustion, but may influence complex downstream signal transduction processes. An understanding of these changes would throw light on the ways in which complex I inhibitors induce a wide range of abnormalities.

A cathepsin F-like peptidase involved in barley grain protein mobilization, HvPap-1, is modulated by its own propeptide and by cystatins

PubMed Central

Diaz, Isabel

2012-01-01

Among the C1A cysteine proteases, the plant cathepsin F-like group has been poorly studied. This paper describes the molecular and functional characterization of the HvPap-1 cathepsin F-like protein from barley. This peptidase is N-glycosylated and has to be processed to become active by its own propeptide being an important modulator of the peptidase activity. The expression pattern of its mRNA and protein suggest that it is involved in different proteolytic processes in the barley plant. HvPap-1 peptidase has been purified in Escherichia coli and the recombinant protein is able to degrade different substrates, including barley grain proteins (hordeins, albumins, and globulins) stored in the barley endosperm. It has been localized in protein bodies and vesicles of the embryo and it is induced in aleurones by gibberellin treatment. These three features support the implication of HvPap-1 in storage protein mobilization during grain germination. In addition, a complex regulation exerted by the barley cystatins, which are cysteine protease inhibitors, and by its own propeptide, is also described PMID:22791822

Knockdown of cytosolic NADP(+) -dependent isocitrate dehydrogenase enhances MPP(+) -induced oxidative injury in PC12 cells.

PubMed

Yang, Eun Sun; Park, Jeen-Woo

2011-05-01

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its toxic metabolite 1-methyl-4-phenylpyridium ion (MPP(+)) have been shown to induce Parkinson's disease-like symptoms as well as neurotoxicity in humans and animal species. Recently, we reported that maintenance of redox balance and cellular defense against oxidative damage are primary functions of the novel antioxidant enzyme cytosolic NADP(+) -dependent isocitrate dehydrogenase (IDPc). In this study, we examined the role of IDPc in cellular defense against MPP(+) -induced oxidative injury using PC12 cells transfected with IDPc small interfering RNA (siRNA). Our results demonstrate that MPP(+) -mediated disruption of cellular redox status, oxidative damage to cells, and apoptotic cell death were significantly enhanced by knockdown of IDPc.

Phase space simulation of collisionless stellar systems on the massively parallel processor

NASA Technical Reports Server (NTRS)

White, Richard L.

1987-01-01

A numerical technique for solving the collisionless Boltzmann equation describing the time evolution of a self gravitating fluid in phase space was implemented on the Massively Parallel Processor (MPP). The code performs calculations for a two dimensional phase space grid (with one space and one velocity dimension). Some results from calculations are presented. The execution speed of the code is comparable to the speed of a single processor of a Cray-XMP. Advantages and disadvantages of the MPP architecture for this type of problem are discussed. The nearest neighbor connectivity of the MPP array does not pose a significant obstacle. Future MPP-like machines should have much more local memory and easier access to staging memory and disks in order to be effective for this type of problem.

Performance analysis of three dimensional integral equation computations on a massively parallel computer. M.S. Thesis

NASA Technical Reports Server (NTRS)

Logan, Terry G.

1994-01-01

The purpose of this study is to investigate the performance of the integral equation computations using numerical source field-panel method in a massively parallel processing (MPP) environment. A comparative study of computational performance of the MPP CM-5 computer and conventional Cray-YMP supercomputer for a three-dimensional flow problem is made. A serial FORTRAN code is converted into a parallel CM-FORTRAN code. Some performance results are obtained on CM-5 with 32, 62, 128 nodes along with those on Cray-YMP with a single processor. The comparison of the performance indicates that the parallel CM-FORTRAN code near or out-performs the equivalent serial FORTRAN code for some cases.

SNJ-1945, a calpain inhibitor, protects SH-SY5Y cells against MPP(+) and rotenone.

PubMed

Knaryan, Varduhi H; Samantaray, Supriti; Park, Sookyoung; Azuma, Mitsuyoshi; Inoue, Jun; Banik, Naren L

2014-07-01

Complex pathophysiology of Parkinson's disease involves multiple CNS cell types. Degeneration in spinal cord neurons alongside brain has been shown to be involved in Parkinson's disease and evidenced in experimental parkinsonism. However, the mechanisms of these degenerative pathways are not well understood. To unravel these mechanisms SH-SY5Y neuroblastoma cells were differentiated into dopaminergic and cholinergic phenotypes, respectively, and used as cell culture model following exposure to two parkinsonian neurotoxicants MPP(+) and rotenone. SNJ-1945, a cell-permeable calpain inhibitor was tested for its neuroprotective efficacy. MPP(+) and rotenone dose-dependently elevated the levels of intracellular free Ca(2+) and induced a concomitant rise in the levels of active calpain. SNJ-1945 pre-treatment significantly protected cell viability and preserved cellular morphology following MPP(+) and rotenone exposure. The neurotoxicants elevated the levels of reactive oxygen species more profoundly in SH-SY5Y cells differentiated into dopaminergic phenotype, and this effect could be attenuated with SNJ-1945 pre-treatment. In contrast, significant levels of inflammatory mediators cyclooxygenase-2 (Cox-2 and cleaved p10 fragment of caspase-1) were up-regulated in the cholinergic phenotype, which could be dose-dependently attenuated by the calpain inhibitor. Overall, SNJ-1945 was efficacious against MPP(+) or rotenone-induced reactive oxygen species generation, inflammatory mediators, and proteolysis. A post-treatment regimen of SNJ-1945 was also examined in cells and partial protection was attained with calpain inhibitor administration 1-3 h after exposure to MPP(+) or rotenone. Taken together, these results indicate that calpain inhibition is a valid target for protection against parkinsonian neurotoxicants, and SNJ-1945 is an efficacious calpain inhibitor in this context. SH-SY5Y cells, differentiated as dopaminergic (TH positive) and cholinergic (ChAT positive), were used as in vitro models for Parkinson's disease. MPP+ and rotenone induced up-regulation of calpain, expression, and activity as a common mechanism of neurodegeneration. SNJ-1945, a novel calpain inhibitor, protected both the cell phenotypes against MPP+ and rotenone. © 2013 International Society for Neurochemistry.

Dynamic Neuromuscular Control of the Lower Limbs in Response to Unexpected Single-Planar versus Multi-Planar Support Perturbations in Young, Active Adults.

PubMed

Malfait, Bart; Staes, Filip; de Vries, Aijse; Smeets, Annemie; Hawken, Malcolm; Robinson, Mark A; Vanrenterghem, Jos; Verschueren, Sabine

2015-01-01

An anterior cruciate ligament (ACL) injury involves a multi-planar injury mechanism. Nevertheless, unexpected multi-planar perturbations have not been used to screen athletes in the context of ACL injury prevention yet could reveal those more at risk. The objective of this study was to compare neuromuscular responses to multi-planar (MPP) and single-planar perturbations (SPP) during a stepping-down task. These results might serve as a basis for future implementation of external perturbations in ACL injury screening programs. Thirteen young adults performed a single leg stepping-down task in eight conditions (four MPP and four SPP with a specified amplitude and velocity). The amplitudes of vastus lateralis (VL), vastus medialis (VM), hamstrings lateralis (HL), hamstrings medialis (HM) EMG activity, medio-lateral and anterior-posterior centre of mass (COM) displacements, the peak knee flexion and abduction angles were compared between conditions using an one-way ANOVA. Number of stepping responses were monitored during all conditions. Significantly greater muscle activity levels were found in response to the more challenging MPP and SPP compared to the less challenging conditions (p < 0.05). No differences in neuromuscular activity were found between the MPP conditions and their equivalents in the SPP. Eighteen stepping responses were monitored in the SPP versus nine in the MPP indicating that the overall neuromuscular control was even more challenged during the SPP which was supported by greater COM displacements in the SPP. The more intense MPP and SPP evoked different neuromuscular responses resulting in greater muscle activity levels compared to small perturbations. Based on the results of COM displacements and based on the amount of stepping responses, dynamic neuromuscular control of the knee joint appeared less challenged during the MPP. Therefore, future work should investigate extensively if other neuromuscular differences (i.e. co-activation patterns and kinetics) exist between MPP and SPP. In addition, future work should examine the influence on the neuromuscular control of the magnitude of the perturbations and the magnitude of stepping height and stepping distance.

Substrate specificity of mitochondrial intermediate peptidase analysed by a support-bound peptide library

PubMed Central

Marcondes, M.F.M.; Alves, F.M.; Assis, D.M.; Hirata, I.Y.; Juliano, L.; Oliveira, V.; Juliano, M.A.

2015-01-01

The substrate specificity of recombinant human mitochondrial intermediate peptidase (hMIP) using a synthetic support-bound FRET peptide library is presented. The collected fluorescent beads, which contained the hydrolysed peptides generated by hMIP, were sequenced by Edman degradation. The results showed that this peptidase presents a remarkable preference for polar uncharged residues at P1 and P1′ substrate positions: Ser = Gln > Thr at P1 and Ser > Thr at P1′. Non-polar residues were frequent at the substrate P3, P2, P2′ and P3′ positions. Analysis of the predicted MIP processing sites in imported mitochondrial matrix proteins shows these cleavages indeed occur between polar uncharged residues. Previous analysis of these processing sites indicated the importance of positions far from the MIP cleavage site, namely the presence of a hydrophobic residue (Phe or Leu) at P8 and a polar uncharged residue (Ser or Thr) at P5. To evaluate this, additional kinetic analyses were carried out, using fluorogenic substrates synthesized based on the processing sites attributed to MIP. The results described here underscore the importance of the P1 and P1′ substrate positions for the hydrolytic activity of hMIP. The information presented in this work will help in the design of new substrate-based inhibitors for this peptidase. PMID:26082885

Genetic correlational analysis reveals no association between MPP+ and the severity of striatal dopaminergic damage following MPTP treatment in BXD mouse strains.

PubMed

Jones, Byron C; O'Callaghan, James P; Lu, Lu; Williams, Robert W; Alam, Gelareh; Miller, Diane B

2014-01-01

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a pro-neurotoxicant that must be metabolized to 1-methyl-4-phenylpyridinium (MPP(+)) and taken up into striatal dopaminergic neurons to produce neurodegeneration. Recently, we showed wide genetic variability in MPTP-associated neuronal damage in a panel of recombinant inbred mouse strains. Here we examined the amount of MPP(+) produced in the striatum in the same strains of inbred BXD mice. This allowed us to determine if the differences in the dopaminergic neurotoxicity and associated astrogliosis among the BXD mouse strains were due to differential metabolism of MPTP to MPP(+). Using the same BXD mouse strains examined previously (Jones et al., 2013) we found that the extent of the striatal damage produced following MPTP treatment is not correlated quantitatively with the production of MPP(+) in the striatum. Our findings also extend those of others regarding strain differences in MPTP-induced dopaminergic neurotoxicity. Importantly, our finding suggests that additional factors influence the neurodegenerative response other than the presence and amount of the toxicant at the target site. Published by Elsevier Inc.

GPR30 Activation Contributes to the Puerarin-Mediated Neuroprotection in MPP+-Induced SH-SY5Y Cell Death.

PubMed

Cheng, Yue-Fa; Zhu, Guoqi; Wu, Qing-Wen; Xie, Yue-Sheng; Jiang, Yan; Guo, Lan; Guan, Ya-Li; Liu, Ying-Shuo; Zhang, Jun

2017-02-01

The neuroprotective action of puerarin in Parkinson's disease (PD) models has been well investigated. However, the mechanisms involved in protection have not been completely understood. G protein-coupled receptor 30 (GPR30) is a G protein-coupled estrogen receptor and considered a potential target in the neuroprotection against PD. In this study, we investigated whether puerarin prevented against 1-methyl-4-phenylpyridinium (MPP + )-induced cell death via GPR30. Our results showed that the GPR30 agonist, G1, exhibited puerarin-mediated neuroprotection against MPP + -induced cell death of SH-SY5Y cells. This protective action was reversed by the GPR30 antagonist. Moreover, a time- and concentration-dependent effect of puerarin on GPR30 expression was verified at the protein level but not at the mRNA level. Further, we showed that an mTor-dependent new GPR30 synthesis contributed to the protection conferred by puerarin. Finally, glial cell line-derived neurotrophic factor (GDNF) levels were enhanced by puerarin and G1 in both control and MPP + -lesioned cells via GPR30. Taken together, our data strongly suggest that puerarin prevents MPP + -induced cell death via facilitating GPR30 expression and GDNF release.

Feasibility of using the Massively Parallel Processor for large eddy simulations and other Computational Fluid Dynamics applications

NASA Technical Reports Server (NTRS)

Bruno, John

1984-01-01

The results of an investigation into the feasibility of using the MPP for direct and large eddy simulations of the Navier-Stokes equations is presented. A major part of this study was devoted to the implementation of two of the standard numerical algorithms for CFD. These implementations were not run on the Massively Parallel Processor (MPP) since the machine delivered to NASA Goddard does not have sufficient capacity. Instead, a detailed implementation plan was designed and from these were derived estimates of the time and space requirements of the algorithms on a suitably configured MPP. In addition, other issues related to the practical implementation of these algorithms on an MPP-like architecture were considered; namely, adaptive grid generation, zonal boundary conditions, the table lookup problem, and the software interface. Performance estimates show that the architectural components of the MPP, the Staging Memory and the Array Unit, appear to be well suited to the numerical algorithms of CFD. This combined with the prospect of building a faster and larger MMP-like machine holds the promise of achieving sustained gigaflop rates that are required for the numerical simulations in CFD.

Dipeptidyl peptidase 4 - An important digestive peptidase in Tenebrio molitor larvae.

PubMed

Tereshchenkova, Valeriia F; Goptar, Irina A; Kulemzina, Irina A; Zhuzhikov, Dmitry P; Serebryakova, Marina V; Belozersky, Mikhail A; Dunaevsky, Yakov E; Oppert, Brenda; Filippova, Irina Yu; Elpidina, Elena N

2016-09-01

Dipeptidyl peptidase 4 (DPP 4) is a proline specific serine peptidase that plays an important role in different regulatory processes in mammals. In this report, we isolated and characterized a unique secreted digestive DPP 4 from the anterior midgut of a stored product pest, Tenebrio molitor larvae (TmDPP 4), with a biological function different than that of the well-studied mammalian DPP 4. The sequence of the purified enzyme was confirmed by mass-spectrometry, and was identical to the translated RNA sequence found in a gut EST database. The purified peptidase was characterized according to its localization in the midgut, and substrate specificity and inhibitor sensitivity were compared with those of human recombinant DPP 4 (rhDPP 4). The T. molitor enzyme was localized mainly in the anterior midgut of the larvae, and 81% of the activity was found in the fraction of soluble gut contents, while human DPP 4 is a membrane enzyme. TmDPP 4 was stable in the pH range 5.0-9.0, with an optimum activity at pH 7.9, similar to human DPP 4. Only specific inhibitors of serine peptidases, diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride, suppressed TmDPP 4 activity, and the specific dipeptidyl peptidase inhibitor vildagliptin was most potent. The highest rate of TmDPP 4 hydrolysis was found for the synthetic substrate Arg-Pro-pNA, while Ala-Pro-pNA was a better substrate for rhDPP 4. Related to its function in the insect midgut, TmDPP 4 efficiently hydrolyzed the wheat storage proteins gliadins, which are major dietary proteins of T. molitor. Published by Elsevier Ltd.

Overexpression of PGC-1α Influences Mitochondrial Signal Transduction of Dopaminergic Neurons.

PubMed

Ye, Qinyong; Huang, Wanling; Li, Dongzhu; Si, Erwang; Wang, Juhua; Wang, Yingqing; Chen, Chun; Chen, Xiaochun

2016-08-01

Parkinson's disease (PD) is a common neurodegenerative disease in the elderly. Mitochondrial dysfunction plays an important role in the pathogenesis of PD. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) is a powerful transcription factor, interacting with multiple transcription factors and widely involving in the regulation of mitochondrial biogenesis, oxidative stress, and other processes. The present study investigated the neuroprotective effects and signal transduction mechanisms of the overexpression of PGC-1α on N-methyl-4-phenylpyridinium ion (MPP(+))-induced mitochondrial damage in SH-SY5Y cell, establishing the cell model of overexpression of PGC-1α and the cell model of PD by using adenoviral vectors and MPP(+). 3-(4,5-Dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide thiazolyl blue (MTT) assay was used to investigate the effects of MPP(+) and adenovirus on the cell viability of SH-SY5Y cells and the cell viability of experimental groups. Western blot and real-time PCR analysis were used to detect the expression of PGC-1α. Flow cytometry and ELISA were used to detect mitochondrial membrane potential and the level of cytochrome C, respectively. The level of intracellular ATP and H2O2 was measured by multifunctional fluorescence microplate. Western blot analysis and real-time PCR were used to observe the expression of estrogen-related receptor α (ERRα), peroxisome proliferator-activated receptor γ (PPARγ), nuclear respiratory factor (NRF)-1, and NRF-2. Confocal fluorescence analysis was used to observe subcellular localization of PGC-1α in SH-SY5Y cells under the intervention of MPP(+). The expression of PGC-1α messenger RNA and protein significantly increased in Adv-PGC-1α + GFP groups, compared with the control and Adv-GFP groups (P < 0.01). The overexpression of PGC-1α could increase mitochondrial membrane potential, reduce the release of mitochondrial cytochrome C, inhibit H2O2 production, and improve the level of ATP in SH-SY5Y cells. The trend of expression of ERRα, PPARγ, and NRF-1 was more consistent with PGC-1α, the most remarkable change is ERRα, but the expression of NRF-2 has no significant changes. Under the gradually increasing concentration of MPP(+), microscale PGC-1α gradually appeared in the cytoplasm of SH-SY5Y cells. The overexpression of PGC-1α can inhibit MPP(+)-induced mitochondrial damage in SH-SY5Y cells, and PGC-1α may realize the neuroprotective effects via the ERRα, PPARγ, and NRF-1 pathway.

Crystal structure and activity studies of the C11 cysteine peptidase from Parabacteroides merdae in the human gut microbiome

DOE PAGES

McLuskey, Karen; Grewal, Jaspreet S.; Das, Debanu; ...

2016-03-03

Clan CD cysteine peptidases, a structurally related group of peptidases that include mammalian caspases, exhibit a wide range of important functions, along with a variety of specificities and activation mechanisms. However, for the clostripain family (denoted C11), little is currently known. Here, we describe the first crystal structure of a C11 protein from the human gut bacterium, Parabacteroides merdae (PmC11), determined to 1.7-Å resolution. PmC11 is a monomeric cysteine peptidase that comprises an extended caspase-like α/β/α sandwich and an unusual C-terminal domain. It shares core structural elements with clan CD cysteine peptidases but otherwise structurally differs from the other familiesmore » in the clan. These studies also revealed a well ordered break in the polypeptide chain at Lys 147, resulting in a large conformational rearrangement close to the active site. Biochemical and kinetic analysis revealed Lys 147 to be an intramolecular processing site at which cleavage is required for full activation of the enzyme, suggesting an autoinhibitory mechanism for self-preservation. PmC11 has an acidic binding pocket and a preference for basic substrates, and accepts substrates with Arg and Lys in P1 and does not require Ca 2+ for activity. Altogether, these data provide insights into the mechanism and activity of PmC11 and a detailed framework for studies on C11 peptidases from other phylogenetic kingdoms.« less

Manganese- and 1-methyl-4-phenylpyridinium-induced neurotoxicity display differences in morphological, electrophysiological and genome-wide alterations: implications for idiopathic Parkinson's disease.

PubMed

Mythri, Rajeswara Babu; Raghunath, Narayana Reddy; Narwade, Santosh Chandrakant; Pandareesh, Mirazkar Dasharatha Rao; Sabitha, Kollarkandi Rajesh; Aiyaz, Mohamad; Chand, Bipin; Sule, Manas; Ghosh, Krittika; Kumar, Senthil; Shankarappa, Bhagyalakshmi; Soundararajan, Soundarya; Alladi, Phalguni Anand; Purushottam, Meera; Gayathri, Narayanappa; Deobagkar, Deepti Dileep; Laxmi, Thenkanidiyoor Rao; Srinivas Bharath, Muchukunte Mukunda

2017-11-01

Idiopathic Parkinson's disease and manganese-induced atypical parkinsonism are characterized by movement disorder and nigrostriatal pathology. Although clinical features, brain region involved and responsiveness to levodopa distinguish both, differences at the neuronal level are largely unknown. We studied the morphological, neurophysiological and molecular differences in dopaminergic neurons exposed to the Parkinson's disease toxin 1-methyl-4-phenylpyridinium ion (MPP + ) and manganese (Mn), followed by validation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and Mn mouse models. Morphological analysis highlighted loss of neuronal processes in the MPP + and not the Mn model. Cellular network dynamics of dopaminergic neurons characterized by spike frequency and inter-spike intervals indicated major neuronal population (~ 93%) with slow discharge rates (0-5 Hz). While MPP + exposure suppressed the firing of these neurons, Mn neither suppressed nor elevated the neuronal activity. High-throughput transcriptomic analysis revealed up-regulation of 694 and 603 genes and down-regulation of 428 and 255 genes in the MPP + and Mn models respectively. Many differentially expressed genes were unique to either models and contributed to neuroinflammation, metabolic/mitochondrial function, apoptosis and nuclear function, synaptic plasticity, neurotransmission and cytoskeleton. Analysis of the Janus kinase-signal transducer and activator of transcription pathway with implications for neuritogenesis and neuronal proliferation revealed contrasting profile in both models. Genome-wide DNA methylomics revealed differences between both models and substantiated the epigenetic basis of the difference in the Janus kinase-signal transducer and activator of transcription pathway. We conclude that idiopathic Parkinson's disease and atypical parkinsonism have divergent neurotoxicological manifestation at the dopaminergic neuronal level with implications for pathobiology and evolution of novel therapeutics. Cover Image for this issue: doi. 10.1111/jnc.13821. © 2017 International Society for Neurochemistry.

Identification of Licopyranocoumarin and Glycyrurol from Herbal Medicines as Neuroprotective Compounds for Parkinson's Disease

PubMed Central

Fujimaki, Takahiro; Saiki, Shinji; Tashiro, Etsu; Yamada, Daisuke; Kitagawa, Mitsuhiro; Hattori, Nobutaka; Imoto, Masaya

2014-01-01

In the course of screening for the anti-Parkinsonian drugs from a library of traditional herbal medicines, we found that the extracts of choi-joki-to and daio-kanzo-to protected cells from MPP+-induced cell death. Because choi-joki-to and daio-kanzo-to commonly contain the genus Glycyrrhiza, we isolated licopyranocoumarin (LPC) and glycyrurol (GCR) as potent neuroprotective principals from Glycyrrhiza. LPC and GCR markedly blocked MPP+-induced neuronal PC12D cell death and disappearance of mitochondrial membrane potential, which were mediated by JNK. LPC and GCR inhibited MPP+-induced JNK activation through the suppression of reactive oxygen species (ROS) generation, thereby inhibiting MPP+-induced neuronal PC12D cell death. These results indicated that LPC and GCR derived from choi-joki-to and daio-kanzo-to would be promising drug leads for PD treatment in the future. PMID:24960051

Kinship-based politics and the optimal size of kin groups

PubMed Central

Hammel, E. A.

2005-01-01

Kin form important political groups, which change in size and relative inequality with demographic shifts. Increases in the rate of population growth increase the size of kin groups but decrease their inequality and vice versa. The optimal size of kin groups may be evaluated from the marginal political product (MPP) of their members. Culture and institutions affect levels and shapes of MPP. Different optimal group sizes, from different perspectives, can be suggested for any MPP schedule. The relative dominance of competing groups is determined by their MPP schedules. Groups driven to extremes of sustainability may react in Malthusian fashion, including fission and fusion, or in Boserupian fashion, altering social technology to accommodate changes in size. The spectrum of alternatives for actors and groups, shaped by existing institutions and natural and cultural selection, is very broad. Nevertheless, selection may result in survival of particular kinds of political structures. PMID:16091466

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haba, Naoyuki; Ishida, Hiroyuki; Okada, Nobuchika

Here, we suggest a scalar singlet extension of the standard model, in which the multiple-point principle (MPP) condition of a vanishing Higgs potential at the Planck scale is realized. Although there have been lots of attempts to realize the MPP at the Planck scale, the realization with keeping naturalness is quite difficult. This model can easily achieve the MPP at the Planck scale without large Higgs mass corrections. It is worth noting that the electroweak symmetry can be radiatively broken in our model. In the naturalness point of view, the singlet scalar mass should be of O(1 TeV) or less.more » Also, we consider right-handed neutrino extension of the model for neutrino mass generation. The model does not affect the MPP scenario, and might keep the naturalness with the new particle mass scale beyond TeV, thanks to accidental cancellation of Higgs mass corrections.« less

Multiple-point principle with a scalar singlet extension of the standard model

DOE PAGES

Haba, Naoyuki; Ishida, Hiroyuki; Okada, Nobuchika; ...

2017-01-21

Here, we suggest a scalar singlet extension of the standard model, in which the multiple-point principle (MPP) condition of a vanishing Higgs potential at the Planck scale is realized. Although there have been lots of attempts to realize the MPP at the Planck scale, the realization with keeping naturalness is quite difficult. This model can easily achieve the MPP at the Planck scale without large Higgs mass corrections. It is worth noting that the electroweak symmetry can be radiatively broken in our model. In the naturalness point of view, the singlet scalar mass should be of O(1 TeV) or less.more » Also, we consider right-handed neutrino extension of the model for neutrino mass generation. The model does not affect the MPP scenario, and might keep the naturalness with the new particle mass scale beyond TeV, thanks to accidental cancellation of Higgs mass corrections.« less

Kinship-based politics and the optimal size of kin groups.

PubMed

Hammel, E A

2005-08-16

Kin form important political groups, which change in size and relative inequality with demographic shifts. Increases in the rate of population growth increase the size of kin groups but decrease their inequality and vice versa. The optimal size of kin groups may be evaluated from the marginal political product (MPP) of their members. Culture and institutions affect levels and shapes of MPP. Different optimal group sizes, from different perspectives, can be suggested for any MPP schedule. The relative dominance of competing groups is determined by their MPP schedules. Groups driven to extremes of sustainability may react in Malthusian fashion, including fission and fusion, or in Boserupian fashion, altering social technology to accommodate changes in size. The spectrum of alternatives for actors and groups, shaped by existing institutions and natural and cultural selection, is very broad. Nevertheless, selection may result in survival of particular kinds of political structures.

A second gene for type I signal peptidase in Bradyrhizobium japonicum, sipF, is located near genes involved in RNA processing and cell division.

PubMed

Bairl, A; Müller, P

1998-11-01

The TnphoA-induced Bradyrhizobium japonicum mutant 184 shows slow growth and aberrant colonization of soybean nodules. Using a DNA fragment adjacent to the transposon insertion site as a probe, a 3.4-kb BglII fragment of B. japonicum 110spc4 DNA was identified and cloned. Sequence analysis indicated that two truncated ORFs and three complete ORFs were encoded on this fragment. A database search revealed homologies to several other prokaryotic proteins: PdxJ (an enzyme involved in vitamin B6 biosynthesis), AcpS (acyl carrier protein synthase), Lep or Sip (prokaryotic type I signal peptidase), RNase III (an endoribonuclease which processes double-stranded rRNA precursors and mRNA) and Era (a GTP-binding protein required for cell division). The mutation in strain 184 was found to lie within the signal peptidase gene, which was designated sipF. Therefore, sipF is located in a region that encodes gene products involved in posttranscriptional and posttranslational processing processes. By complementation of the lep(ts) E. coli mutant strain IT41 it was demonstrated that sipF indeed encodes a functional signal peptidase, and genetic complementation of B. japonicum mutant 184 by a 2.8-kb SalI fragment indicated that sipF is expressed from a promoter located directly upstream of sipF. Using a non-polar kanamycin resistance cassette, a specific sipF mutant was constructed which exhibited defects in symbiosis similar to those of the original mutant 184.

Proteolytic cleavage by the inner membrane peptidase (IMP) complex or Oct1 peptidase controls the localization of the yeast peroxiredoxin Prx1 to distinct mitochondrial compartments.

PubMed

Gomes, Fernando; Palma, Flávio Romero; Barros, Mario H; Tsuchida, Eduardo T; Turano, Helena G; Alegria, Thiago G P; Demasi, Marilene; Netto, Luis E S

2017-10-13

Yeast Prx1 is a mitochondrial 1-Cys peroxiredoxin that catalyzes the reduction of endogenously generated H 2 O 2 Prx1 is synthesized on cytosolic ribosomes as a preprotein with a cleavable N-terminal presequence that is the mitochondrial targeting signal, but the mechanisms underlying Prx1 distribution to distinct mitochondrial subcompartments are unknown. Here, we provide direct evidence of the following dual mitochondrial localization of Prx1: a soluble form in the intermembrane space and a form in the matrix weakly associated with the inner mitochondrial membrane. We show that Prx1 sorting into the intermembrane space likely involves the release of the protein precursor within the lipid bilayer of the inner membrane, followed by cleavage by the inner membrane peptidase. We also found that during its import into the matrix compartment, Prx1 is sequentially cleaved by mitochondrial processing peptidase and then by octapeptidyl aminopeptidase 1 (Oct1). Oct1 cleaved eight amino acid residues from the N-terminal region of Prx1 inside the matrix, without interfering with its peroxidase activity in vitro Remarkably, the processing of peroxiredoxin (Prx) proteins by Oct1 appears to be an evolutionarily conserved process because yeast Oct1 could cleave the human mitochondrial peroxiredoxin Prx3 when expressed in Saccharomyces cerevisiae Altogether, the processing of peroxiredoxins by Imp2 or Oct1 likely represents systems that control the localization of Prxs into distinct compartments and thereby contribute to various mitochondrial redox processes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Topical Ocular Drug Delivery to the Back of the Eye by Mucus-Penetrating Particles

PubMed Central

Schopf, Lisa R.; Popov, Alexey M.; Enlow, Elizabeth M.; Bourassa, James L.; Ong, Winston Z.; Nowak, Pawel; Chen, Hongming

2015-01-01

Purpose: Enhanced drug exposure to the ocular surface typically relies on inclusion of viscosity-enabling agents, whereas delivery to the back of the eye generally focuses on invasive means, such as intraocular injections. Using our novel mucus-penetrating particle (MPP) technology, which rapidly and uniformly coats and penetrates mucosal barriers, we evaluated if such drug formulations could increase ocular drug exposure and improve topical drug delivery. Methods: Pharmacokinetic (PK) profiling of topically administered loterprednol etabonate formulated as MPP (LE-MPP) was performed in rabbits and a larger species, the mini-pig. Pharmacodynamic evaluation was done in a rabbit model of VEGF-induced retinal vascular leakage. Cellular potency and PK profile were determined for a second compound, KAL821, a novel receptor tyrosine kinase inhibitor (RTKi). Results: We demonstrated in animals that administration of LE-MPP increased exposure at the ocular surface and posterior compartments. Furthermore using a rabbit vascular leakage model, we demonstrated that biologically effective drug concentrations of LE were delivered to the back of the eye using the MPP technology. We also demonstrated that a novel RTKi formulated as MPPs provided drug levels to the back of the eye above its cellular inhibitory concentration. Conclusions: Topical dosing of MPPs of LE or KAL821 enhanced drug exposure at the front of the eye, and delivered therapeutically relevant drug concentrations to the back of the eye, in animals. Translational Relevance: These preclinical data support using MPP technology to engineer topical formulations to deliver therapeutic drug levels to the back of the eye and could provide major advancements in managing sight-threatening diseases. PMID:26101724

Polynomial algorithms for the Maximal Pairing Problem: efficient phylogenetic targeting on arbitrary trees

PubMed Central

2010-01-01

Background The Maximal Pairing Problem (MPP) is the prototype of a class of combinatorial optimization problems that are of considerable interest in bioinformatics: Given an arbitrary phylogenetic tree T and weights ωxy for the paths between any two pairs of leaves (x, y), what is the collection of edge-disjoint paths between pairs of leaves that maximizes the total weight? Special cases of the MPP for binary trees and equal weights have been described previously; algorithms to solve the general MPP are still missing, however. Results We describe a relatively simple dynamic programming algorithm for the special case of binary trees. We then show that the general case of multifurcating trees can be treated by interleaving solutions to certain auxiliary Maximum Weighted Matching problems with an extension of this dynamic programming approach, resulting in an overall polynomial-time solution of complexity (n4 log n) w.r.t. the number n of leaves. The source code of a C implementation can be obtained under the GNU Public License from http://www.bioinf.uni-leipzig.de/Software/Targeting. For binary trees, we furthermore discuss several constrained variants of the MPP as well as a partition function approach to the probabilistic version of the MPP. Conclusions The algorithms introduced here make it possible to solve the MPP also for large trees with high-degree vertices. This has practical relevance in the field of comparative phylogenetics and, for example, in the context of phylogenetic targeting, i.e., data collection with resource limitations. PMID:20525185

Next Generation Sequencing Identifies Five Major Classes of Potentially Therapeutic Enzymes Secreted by Lucilia sericata Medical Maggots.

PubMed

Franta, Zdeněk; Vogel, Heiko; Lehmann, Rüdiger; Rupp, Oliver; Goesmann, Alexander; Vilcinskas, Andreas

2016-01-01

Lucilia sericata larvae are used as an alternative treatment for recalcitrant and chronic wounds. Their excretions/secretions contain molecules that facilitate tissue debridement, disinfect, or accelerate wound healing and have therefore been recognized as a potential source of novel therapeutic compounds. Among the substances present in excretions/secretions various peptidase activities promoting the wound healing processes have been detected but the peptidases responsible for these activities remain mostly unidentified. To explore these enzymes we applied next generation sequencing to analyze the transcriptomes of different maggot tissues (salivary glands, gut, and crop) associated with the production of excretions/secretions and/or with digestion as well as the rest of the larval body. As a result we obtained more than 123.8 million paired-end reads, which were assembled de novo using Trinity and Oases assemblers, yielding 41,421 contigs with an N50 contig length of 2.22 kb and a total length of 67.79 Mb. BLASTp analysis against the MEROPS database identified 1729 contigs in 577 clusters encoding five peptidase classes (serine, cysteine, aspartic, threonine, and metallopeptidases), which were assigned to 26 clans, 48 families, and 185 peptidase species. The individual enzymes were differentially expressed among maggot tissues and included peptidase activities related to the therapeutic effects of maggot excretions/secretions.

A marked point process approach for identifying neural correlates of tics in Tourette Syndrome.

PubMed

Loza, Carlos A; Shute, Jonathan B; Principe, Jose C; Okun, Michael S; Gunduz, Aysegul

2017-07-01

We propose a novel interpretation of local field potentials (LFP) based on a marked point process (MPP) framework that models relevant neuromodulations as shifted weighted versions of prototypical temporal patterns. Particularly, the MPP samples are categorized according to the well known oscillatory rhythms of the brain in an effort to elucidate spectrally specific behavioral correlates. The result is a transient model for LFP. We exploit data-driven techniques to fully estimate the model parameters with the added feature of exceptional temporal resolution of the resulting events. We utilize the learned features in the alpha and beta bands to assess correlations to tic events in patients with Tourette Syndrome (TS). The final results show stronger coupling between LFP recorded from the centromedian-paraficicular complex of the thalamus and the tic marks, in comparison to electrocorticogram (ECoG) recordings from the hand area of the primary motor cortex (M1) in terms of the area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

A Most Probable Point-Based Method for Reliability Analysis, Sensitivity Analysis and Design Optimization

NASA Technical Reports Server (NTRS)

Hou, Gene J.-W; Newman, Perry A. (Technical Monitor)

2004-01-01

A major step in a most probable point (MPP)-based method for reliability analysis is to determine the MPP. This is usually accomplished by using an optimization search algorithm. The minimum distance associated with the MPP provides a measurement of safety probability, which can be obtained by approximate probability integration methods such as FORM or SORM. The reliability sensitivity equations are derived first in this paper, based on the derivatives of the optimal solution. Examples are provided later to demonstrate the use of these derivatives for better reliability analysis and reliability-based design optimization (RBDO).

Effect of a Traditional Chinese Herbal Medicine Formulation on Cell Survival and Apoptosis of MPP+-Treated MES 23.5 Dopaminergic Cells

PubMed Central

Koon, Ho Kee; Fan, Wen; Wei, Wei; Xu, Chuanshan

2017-01-01

Progressive degeneration of dopaminergic neurons in the substantia nigra (SN) is implicated in Parkinson's disease (PD). The efficacy of these currently used drugs is limited while traditional Chinese medicine (TCM) has been used in the management of neurodegenerative diseases for many years. This study was designed to evaluate the effect of a modified traditional Chinese herbal medicine decoction, Cong Rong Jing (CRJ), on cell survival and apoptosis of 1-methyl-4-phenylpyridinium- (MPP+-) treated MES23.5 dopaminergic cells. CRJ was prepared as a decoction from three Chinese herbs, namely, Herba Cistanches, Herba Epimedii, and Rhizoma Polygonati. We reported here that CRJ significantly enhanced the cell survival of MES23.5 cells after the exposure of MPP+ and inhibited the production of intracellular reactive oxygen species (ROS) induced by MPP+. CRJ also prevented the MPP+-treated MES23.5 cells from apoptosis by reducing the externalization of phosphatidylserine and enhancing the Bcl-2/Bax protein expression ratio. Signaling proteins such as JAK2, STAT3, and ERK1/2 were also involved in the action of CRJ. Taken together, these results provide a preliminary mechanism to support clinical application of the TCM formulation in PD and possibly other neurodegenerative diseases associated with ROS injury and apoptosis. PMID:28607800

Nicotine suppresses the neurotoxicity by MPP+/MPTP through activating α7nAChR/PI3K/Trx-1 and suppressing ER stress.

PubMed

Cai, Yanxue; Zhang, Xianwen; Zhou, Xiaoshuang; Wu, Xiaoli; Li, Yanhui; Yao, Jianhua; Bai, Jie

2017-03-01

Parkinson's disease (PD) is a neurodegenerative disease. Nicotine has been reported to have the role in preventing Parkinson's disease. However, its mechanism is still unclear. In present study we found that nicotine suppressed 1-methyl-4-phenylpyridinium ion(MPP + ) toxicity in PC12 cells by MTT assay. The expression of thioredoxin-1(Trx-1) was decreased by MPP + , which was restored by nicotine. The nicotine suppressed expressions of Glucose-regulated protein 78(GRP78/Bip) and C/EBP homologous protein (CHOP) induced by MPP + . The methyllycaconitine (MLA), the inhibitor of α7nAChR and LY294002, the inhibitor of phosphatidylinositol 3-kinase (PI3K) blocked the suppressions of above molecules, respectively. Consistently, pretreatment with nicotine ameliorated the motor ability, restored the declines of Trx-1 and tyrosine hydroxylase (TH), and suppressed the expressions of Bip and CHOP induced by 1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice. Our results suggest that nicotine plays role in resisting MPP + /MPTP neurotoxicity through activating the α7nAChR/PI3K/Trx-1 pathway and suppressing ER stress. Copyright © 2017 Elsevier B.V. All rights reserved.

The neuroprotective effect of lovastatin on MPP(+)-induced neurotoxicity is not mediated by PON2.

PubMed

Aguirre-Vidal, Yoshajandith; Montes, Sergio; Tristan-López, Luis; Anaya-Ramos, Laura; Teiber, John; Ríos, Camilo; Baron-Flores, Verónica; Monroy-Noyola, Antonio

2015-05-01

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of the pigmented dopaminergic neurons in the substantia nigra pars compacta with subsequent striatal dopamine (DA) deficiency and increased lipid peroxidation. The etiology of the disease is still unclear and it is thought that PD may be caused by a combination of genetic and environmental factors. In the search of new pharmacological options, statins have been recognized for their potential application to treat PD, due to their antioxidant effect. The aim of this work is to contribute in the characterization of the neuroprotective effect of lovastatin in a model of PD induced by 1-methyl-4-phenylpyridinium (MPP(+)). Male Wistar rats (200-250 g) were randomly allocated into 4 groups and administered for 7 days with different pharmacological treatments. Lovastatin administration (5 mg/kg) diminished 40% of the apomorphine-induced circling behavior, prevented the striatal DA depletion and lipid peroxides formation by MPP(+) intrastriatal injection, as compared to the group of animals treated only with MPP(+). Lovastatin produced no change in paraoxonase-2 (PON2) activity. It is evident that lovastatin conferred neuroprotection against MPP(+)-induced protection but this effect was not associated with the induction of PON2 in the rat striatum. Copyright © 2015. Published by Elsevier B.V.

The global cysteine peptidase landscape in parasites

PubMed Central

Atkinson, Holly J; Babbitt, Patricia C; Sajid, Mohammed

2013-01-01

The accumulation of sequenced genomes has expanded the already sizeable population of cysteine peptidases from parasites. Characterization of a few of these enzymes has ascribed key roles to peptidases in parasite life cycles and also shed light on mechanisms of pathogenesis. Here, we discuss recent observations on the physiological activities of cysteine peptidases of parasitic organisms, paired with a global view of all cysteine peptidases from the MEROPS database grouped by similarity. This snapshot of the landscape of parasite cysteine peptidases is complex and highly populated, which suggests that expansion of research beyond the few ‘model’ parasite peptidases is now timely. PMID:19854678

Roles of proteolysis in regulation of GPCR function

PubMed Central

Cottrell, GS

2013-01-01

The enzymatic activity of peptidases must be tightly regulated to prevent uncontrolled hydrolysis of peptide bonds, which could have devastating effects on biological systems. Peptidases are often generated as inactive propeptidases, secreted with endogenous inhibitors, or they are compartmentalized. Propeptidases become active after proteolytic removal of N-terminal activation peptides by other peptidases. Some peptidases only become active towards substrates only at certain pHs, thus confining activity to specific compartments or conditions. This review discusses the different roles proteolysis plays in regulating GPCRs. At the cell-surface, certain GPCRs are regulated by the hydrolytic inactivation of bioactive peptides by membrane-anchored peptidases, which prevent signalling. Conversely, cell-surface peptidases can also generate bioactive peptides, which directly activate GPCRs. Alternatively, cell-surface peptidases activated by GPCRs, can generate bioactive peptides to cause transactivation of receptor tyrosine kinases, thereby promoting signalling. Certain peptidases can signal directly to cells, by cleaving GPCR to initiate intracellular signalling cascades. Intracellular peptidases also regulate GPCRs; lysosomal peptidases destroy GPCRs in lysosomes to permanently terminate signalling and mediate down-regulation; endosomal peptidases cleave internalized peptide agonists to regulate GPCR recycling, resensitization and signalling; and soluble intracellular peptidases also participate in GPCR function by regulating the ubiquitination state of GPCRs, thereby altering GPCR signalling and fate. Although the use of peptidase inhibitors has already brought success in the treatment of diseases such as hypertension, the discovery of new regulatory mechanisms involving proteolysis that control GPCRs may provide additional targets to modulate dysregulated GPCR signalling in disease. PMID:23043558

Diversity and Phylogenetic Distribution of Extracellular Microbial Peptidases

NASA Astrophysics Data System (ADS)

Nguyen, Trang; Mueller, Ryan; Myrold, David

2017-04-01

Depolymerization of proteinaceous compounds by extracellular proteolytic enzymes is a bottleneck in the nitrogen cycle, limiting the rate of the nitrogen turnover in soils. Protein degradation is accomplished by a diverse range of extracellular (secreted) peptidases. Our objective was to better understand the evolution of these enzymes and how their functional diversity corresponds to known phylogenetic diversity. Peptidase subfamilies from 110 archaeal, 1,860 bacterial, and 97 fungal genomes were extracted from the MEROPS database along with corresponding SSU sequences for each genome from the SILVA database, resulting in 43,177 secreted peptidases belonging to 34 microbial phyla and 149 peptidase subfamilies. We compared the distribution of each peptidase subfamily across all taxa to the phylogenetic relationships of these organisms based on their SSU gene sequences. The occurrence and abundance of genes coding for secreted peptidases varied across microbial taxa, distinguishing the peptidase complement of the three microbial kingdoms. Bacteria had the highest frequency of secreted peptidase coding genes per 1,000 genes and contributed from 1% to 6% of the gene content. Fungi only had a slightly higher number of secreted peptidase gene content than archaea, standardized by the total genes. The relative abundance profiles of secreted peptidases in each microbial kingdom also varied, in which aspartic family was found to be the greatest in fungi (25%), whereas it was only 12% in archaea and 4% in bacteria. Serine, metallo, and cysteine families consistently contributed widely up to 75% of the secreted peptidase abundance across the three kingdoms. Overall, bacteria had a much wider collection of secreted peptidases, whereas fungi and archaea shared most of their secreted peptidase families. Principle coordinate analysis of the peptidase subfamily-based dissimilarities showed distinguishable clusters for different groups of microorganisms. The distribution of secreted peptidases was found to be significantly correlated with phylogenetic relationships within kingdoms (archaea rMantel=0.364, p=0.001; bacteria rMantel=0.257, p=0.001, and fungi rMantel=0.281, p=0.005), inferring an evolutionary relationship where subsets of phylogenetically related organisms share similar types of secreted peptidases. We also tested the phylogenetic signal strength of each peptidase subfamily for each microbial kingdom based on the binary traits of the distribution (presence or absence of secreted peptidase subfamilies in individual species). About one-third of the peptidase subfamilies displayed a strong evolutionary signal; the rest were phylogenetically over-dispersed, suggesting that these subfamilies are randomly distributed across the tree of life or the result of events such as horizontal gene transfer. Study of the diversity and phylogenetic distribution of secreted peptidases offered a mechanistic basis to anticipate the proteolytic potential function of microbial communities.

Functional characterization of estrogen receptor subtypes, ER{alpha} and ER{beta}, mediating vitellogenin production in the liver of rainbow trout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leanos-Castaneda, Olga; Kraak, Glen van der

2007-10-15

The estrogen-dependent process of vitellogenesis is a key function on oviparous fish reproduction and it has been widely used as an indicator of xenoestrogen exposure. The two estrogen receptor (ER) subtypes, ER{alpha} and ER{beta}, are often co-expressed in the liver of fish. The relative contribution of each ER subtype to modulate vitellogenin production by hepatocytes was studied using selected compounds known to preferentially interact with specific ER subtypes: propyl-pyrazole-triol (PPT) an ER{alpha} selective agonist, methyl-piperidino-pyrazole (MPP) an ER{alpha} selective antagonist, and diarylpropionitrile (DPN) an ER{beta} selective agonist. First, the relative binding affinity of the test compounds to estradiol for rainbowmore » trout hepatic nuclear ER was determined using a competitive ligand binding assay. All the test ligands achieved complete displacement of specific [{sup 3}H]-estradiol binding from the nuclear ER extract. This indicates that the test ligands have the potential to modify the ER function in the rainbow trout liver. Secondly, the ability of the test compounds to induce or inhibit vitellogenin production by primary cultures of rainbow trout hepatocytes was studied. Estradiol and DPN were the only compounds that induced a dose-dependent increase on vitellogenin synthesis. The lack of vitellogenin induction by PPT indicates that ER{alpha} could not have a role on this reproductive process whereas the ability of DPN to induce vitellogenin production supports the participation of ER{beta}. In addition, this hypothesis is reinforced by the results obtained from MPP plus estradiol. On one hand, the absence of suppressive activity of MPP in the estradiol-induced vitellogenin production does not support the participation of ER{alpha}. On the other hand, once blocked ER{alpha} with MPP, the only manifestation of agonist activity of estradiol would be achieved via ER{beta}. In conclusion, the present results indicate that vitellogenin production is mainly mediated through ER{beta}, implying, furthermore that compounds which only exhibit ER{alpha} selectivity are not detected by vitellogenin bioassay.« less

Multipoint Pacing versus conventional ICD in Patients with a Narrow QRS complex (MPP Narrow QRS trial): study protocol for a pilot randomized controlled trial.

PubMed

Gasparini, Maurizio; Galimberti, Paola; Bragato, Renato; Ghio, Stefano; Raineri, Claudia; Landolina, Maurizio; Chieffo, Enrico; Lunati, Maurizio; Mulargia, Ederina; Proclemer, Alessandro; Facchin, Domenico; Rordorf, Roberto; Vicentini, Alessandro; Marcantoni, Lina; Zanon, Francesco; Klersy, Catherine

2016-12-03

Despite an intensive search for predictors of the response to cardiac resynchronization therapy (CRT), the QRS duration remains the simplest and most robust predictor of a positive response. QRS duration of ≥ 130 ms is considered to be a prerequisite for CRT; however, some studies have shown that CRT may also be effective in heart failure (HF) patients with a narrow QRS (<130 ms). Since CRT can now be performed by pacing the left ventricle from multiple vectors via a single quadripolar lead, it is possible that multipoint pacing (MPP) might be effective in HF patients with a narrow QRS. This article reports the design of the MPP Narrow QRS trial, a prospective, randomized, multicenter, controlled feasibility study to investigate the efficacy of MPP using two LV pacing vectors in patients with a narrow QRS complex (100-130 ms). Fifty patients with a standard ICD indication will be enrolled and randomized (1:1) to either an MPP group or a Standard ICD group. All patients will undergo a low-dose dobutamine stress echo test and only those with contractile reserve will be included in the study and randomized. The primary endpoint will be the percentage of patients in each group that have reverse remodeling at 12 months, defined as a reduction in left ventricular end-systolic volume (LVESV) of >15% from the baseline. This feasibility study will determine whether MPP improves reverse remodeling, as compared with standard ICD, in HF patients who have a narrow QRS complex (100-130 ms). ClinicalTrials.gov, NCT02402816 . Registered on 25 March 2015.

SNJ-1945, a calpain inhibitor, protects SH-SY5Y cells against MPP+ and rotenone

PubMed Central

Knaryan, Varduhi H.; Samantaray, Supriti; Sookyoung, Park; Azuma, Mitsuyoshi; Inoue, Jun; Banik, Naren L.

2014-01-01

Complex pathophysiology of Parkinson’s disease (PD) involves multiple CNS cell types. Degeneration in spinal cord neurons alongside brain has been shown to be involved in PD and evidenced in experimental parkinsonism. However, the mechanisms of these degenerative pathways are not well understood. In order to unravel these mechanisms SH-SY5Y neuroblastoma cells were differentiated into dopaminergic and cholinergic phenotypes respectively and used as cell culture model following exposure to two parkinsonian neurotoxicants MPP+ and rotenone. SNJ-1945, a cell-permeable calpain inhibitor was tested for its neuroprotective efficacy. MPP+ and rotenone dose-dependently elevated the levels of intracellular free Ca2+ and induced a concomitant rise in the levels of active calpain. SNJ-1945 pre-treatment significantly protected cell viability and preserved cellular morphology following MPP+ and rotenone exposure. The neurotoxicants elevated the levels of reactive oxygen species (ROS) more profoundly in SH-SY5Y cells differentiated into dopaminergic phenotype, and this effect could be attenuated with SNJ-1945 pre-treatment. In contrast, significant levels of inflammatory mediators (cyclooxygenase-2, Cox-2 and cleaved p10 fragment of caspase-1) were upregulated in the cholinergic phenotype, which could be dose-dependently attenuated by the calpain inhibitor. Overall, SNJ-1945 was efficacious against MPP+ or rotenone-induced ROS generation, inflammatory mediators, and proteolysis. A post-treatment regimen of SNJ-1945 was also examined in cells and partial protection was attained with calpain inhibitor administration 1–3 h after exposure to MPP+ or rotenone. Taken together these results indicate that calpain inhibition is a valid target for protection against parkinsonian neurotoxicants, and SNJ-1945 is an efficacious calpain inhibitor in this context. PMID:24341912

Comparative effects of estradiol, methyl-piperidino-pyrazole, raloxifene, and ICI 182 780 on gene expression in the murine uterus.

PubMed

Davis, Angela M; Mao, Jiude; Naz, Bushra; Kohl, Jessica A; Rosenfeld, Cheryl S

2008-10-01

Selective estrogen receptor modulators (SERMs) are potentially useful in treating various endometrial disorders, including endometrial cancer, as they block some of the detrimental effects of estrogen. It remains unclear whether each SERM regulates a unique subset of genes and, if so, whether the combination of a SERM and 17beta-estradiol has an additive or synergistic effect on gene expression. We performed microarray analysis with Affymetrix Mouse Genome 430 2.0 short oligomer arrays to determine gene expression changes in uteri of ovariectomized mice treated with estradiol (low and high dose), methyl-piperidino-pyrazole (MPP), ICI 182 780, raloxifene, and combinations of high dose of estradiol with one of the SERM and dimethyl sulfoxide (DMSO) vehicle control. The nine treatments clustered into two groups, with MPP, raloxifene, and high dose of estradiol in one, and low dose of estradiol, ICI + estradiol, ICI, MPP + estradiol, and raloxifene + estradiol in the second group. Surprisingly, combining a high dose of estradiol with a SERM markedly increased (P<0.02) the number of regulated genes compared with each individual treatment. Analysis of expression for selected genes in uteri of estradiol and SERM-treated mice by quantitative (Q)RT-PCR generally supported the microarray results. For some cancer-associated genes, including Klk1, Ihh, Cdc45l, and Cdca8, administration of MPP or raloxifene with estradiol resulted in greater expression than estradiol alone (P<0.05). By contrast, ICI 182 780 suppressed more genes governing DNA replication compared with MPP and raloxifene treatments. Therefore, ICI 182 780 might be superior to MPP and raloxifene to treat estrogen-induced endometrial cancer in women.

Bioinformatic analysis of the neprilysin (M13) family of peptidases reveals complex evolutionary and functional relationships.

PubMed

Bland, Nicholas D; Pinney, John W; Thomas, Josie E; Turner, Anthony J; Isaac, R Elwyn

2008-01-23

The neprilysin (M13) family of endopeptidases are zinc-metalloenzymes, the majority of which are type II integral membrane proteins. The best characterised of this family is neprilysin, which has important roles in inactivating signalling peptides involved in modulating neuronal activity, blood pressure and the immune system. Other family members include the endothelin converting enzymes (ECE-1 and ECE-2), which are responsible for the final step in the synthesis of potent vasoconstrictor endothelins. The ECEs, as well as neprilysin, are considered valuable therapeutic targets for treating cardiovascular disease. Other members of the M13 family have not been functionally characterised, but are also likely to have biological roles regulating peptide signalling. The recent sequencing of animal genomes has greatly increased the number of M13 family members in protein databases, information which can be used to reveal evolutionary relationships and to gain insight into conserved biological roles. The phylogenetic analysis successfully resolved vertebrate M13 peptidases into seven classes, one of which appears to be specific to mammals, and insect genes into five functional classes and a series of expansions, which may include inactive peptidases. Nematode genes primarily resolved into groups containing no other taxa, bar the two nematode genes associated with Drosophila DmeNEP1 and DmeNEP4. This analysis reconstructed only one relationship between chordate and invertebrate clusters, that of the ECE sub-group and the DmeNEP3 related genes. Analysis of amino acid utilisation in the active site of M13 peptidases reveals a basis for their biochemical properties. A relatively invariant S1' subsite gives the majority of M13 peptidases their strong preference for hydrophobic residues in P1' position. The greater variation in the S2' subsite may be instrumental in determining the specificity of M13 peptidases for their substrates and thus allows M13 peptidases to fulfil a broad range of physiological roles. The M13 family of peptidases have diversified extensively in all species examined, indicating wide ranging roles in numerous physiological processes. It is predicted that differences in the S2' subsite are fundamental to determining the substrate specificities that facilitate this functional diversity.

The Regulation of a Post-Translational Peptide Acetyltransferase: Strategies for Selectively Modifying the Biological Activity of Neural and Endocrine Peptides

DTIC Science & Technology

1991-05-01

peptidase H is not induced by chronic haloperidol treatment (Fig. 3). That peptide acetyltransferase, but not carboxypeptidase H, is induced by...J.F., Millington, W.R., Schwaber, J.S. and Lewis. M.E. NPY, somatostatin and a-MSH: Combined in situ hybridization, immunohistochemistry and axonal...365-372, 1985. Fricker, L.D. Neuropeptide biosynthesis: focus on the carboxy- peptidase processing enzyme. Trends in Neurosciences 8:210-214, 1985

Development and qualitative evaluation of an adapted return to work guideline for the sick-listed unemployed and temporary agency workers with minor psychological problems

PubMed Central

2012-01-01

Background Among the working population, unemployed and temporary agency workers with psychological problems are a particularly vulnerable group, at risk for sickness absence and prolonged work disability. There is a need for the development of a new protocol for this group, because the existing return to work (RTW) interventions, including practice guidelines, do not address the situation when there is no workplace to return to. The purpose of this study was to (1) describe the adaptations needed in the practice guideline for employed workers to enable its use by insurance physicians (IPs) for counselling of sick-listed unemployed and temporary agency workers with minor psychological problems; and (2) evaluate the experiences of IPs when using the new guidance document for minor psychological problems (MPP guidance document). Methods The MPP guidance document for unemployed and temporary agency workers was developed through discussions with nine IPs and with the help of an expert. Semi-structured interviews with five IPs were then held to evaluate the IPs’ field experience using the MPP guidance document, in terms of (a) feasibility and (b) perceived usefulness of the MPP guidance document. Results The main adaptation introduced in the guideline is that interaction with the workplace, which is absent in this population, needed to be established in an alternative way, i.e., through the involvement of vocational rehabilitation agencies and labour experts. Overall, the guideline required minimal changes. In total, nineteen sick-listed workers were counselled using the MPP guidance document. The overall experience of the IPs was that the MPP guidance document was feasible and useful for the IP, while they had mixed responses on its usefulness for the sick-listed worker, in part due to the follow-up period of this study. Conclusions An existing practice guideline for employed workers was adapted for use as a guidance document for unemployed and temporary agency workers with minor psychological problems. IPs were positive about applying the MPP guidance document. The guidance document provides opportunities for RTW counselling for unemployed and temporary agency workers with minor psychological problems. PMID:23014258

Treg Cells Protect Dopaminergic Neurons against MPP+ Neurotoxicity via CD47-SIRPA Interaction.

PubMed

Huang, Yan; Liu, Zhan; Cao, Bei-Bei; Qiu, Yi-Hua; Peng, Yu-Ping

2017-01-01

Regulatory T (Treg) cells have been associated with neuroprotection by inhibiting microglial activation in animal models of Parkinson's disease (PD), a progressive neurodegenerative disease characterized by dopaminergic neuronal loss in the nigrostriatal system. Herein, we show that Treg cells directly protect dopaminergic neurons against 1-methyl-4-phenylpyridinium (MPP+) neurotoxicity via an interaction between the two transmembrane proteins CD47 and signal regulatory protein α (SIRPA). Primary ventral mesencephalic (VM) cells or VM neurons were pretreated with Treg cells before MPP+ treatment. Transwell co-culture of Treg cells and VM neurons was used to assess the effects of the Treg cytokines transforming growth factor (TGF)-β1 and interleukin (IL)-10 on dopaminergic neurons. Live cell imaging system detected a dynamic contact of Treg cells with VM neurons that were stained with CD47 and SIRPA, respectively. Dopaminergic neuronal loss, which was assessed by the number of tyrosine hydroxylase (TH)-immunoreactive cells, was examined after silencing CD47 in Treg cells or silencing SIRPA in VM neurons. Treg cells prevented MPP+-induced dopaminergic neuronal loss and glial inflammatory responses. TGF-β1 and IL-10 secreted from Treg cells did not significantly prevent MPP+-induced dopaminergic neuronal loss in transwell co-culture of Treg cells and VM neurons. CD47 and SIRPA were expressed by Treg cells and VM neurons, respectively. CD47-labeled Treg cells dynamically contacted with SIRPA-labeled VM neurons. Silencing CD47 gene in Treg cells impaired the ability of Treg cells to protect dopaminergic neurons against MPP+ toxicity. Similarly, SIRPA knockdown in VM neurons reduced the ability of Treg cell neuroprotection. Rac1/Akt signaling pathway in VM neurons was activated by CD47-SIRPA interaction between Treg cells and the neurons. Inhibiting Rac1/Akt signaling in VM neurons compromised Treg cell neuroprotection. Treg cells protect dopaminergic neurons against MPP+ neurotoxicity by a cell-to-cell contact mechanism underlying CD47-SIRPA interaction and Rac1/Akt activation. © 2017 The Author(s)Published by S. Karger AG, Basel.

Trelagliptin (SYR-472, Zafatek), novel once-weekly treatment for type 2 diabetes, inhibits dipeptidyl peptidase-4 (DPP-4) via a non-covalent mechanism

DOE PAGES

Grimshaw, Charles E.; Jennings, Andy; Kamran, Ruhi; ...

2016-06-21

Trelagliptin (SYR-472), a novel dipeptidyl peptidase-4 inhibitor, shows sustained efficacy by once-weekly dosing in type 2 diabetes patients. In this study, we characterized in vitro properties of trelagliptin, which exhibited approximately 4-and 12-fold more potent inhibition against human dipeptidyl peptidase-4 than alogliptin and sitagliptin, respectively, and >10,000-fold selectivity over related proteases including dipeptidyl peptidase-8 and dipeptidyl peptidase-9. Kinetic analysis revealed reversible, competitive and slow-binding inhibition of dipeptidyl peptidase-4 by trelagliptin (t 1/2 for dissociation ≈ 30 minutes). X-ray diffraction data indicated a non-covalent interaction between dipeptidyl peptidase and trelagliptin. Altogether, potent dipeptidyl peptidase inhibitionmay partially contribute to sustained efficacy ofmore » trelagliptin.« less

Trelagliptin (SYR-472, Zafatek), novel once-weekly treatment for type 2 diabetes, inhibits dipeptidyl peptidase-4 (DPP-4) via a non-covalent mechanism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grimshaw, Charles E.; Jennings, Andy; Kamran, Ruhi

Trelagliptin (SYR-472), a novel dipeptidyl peptidase-4 inhibitor, shows sustained efficacy by once-weekly dosing in type 2 diabetes patients. In this study, we characterized in vitro properties of trelagliptin, which exhibited approximately 4-and 12-fold more potent inhibition against human dipeptidyl peptidase-4 than alogliptin and sitagliptin, respectively, and >10,000-fold selectivity over related proteases including dipeptidyl peptidase-8 and dipeptidyl peptidase-9. Kinetic analysis revealed reversible, competitive and slow-binding inhibition of dipeptidyl peptidase-4 by trelagliptin (t 1/2 for dissociation ≈ 30 minutes). X-ray diffraction data indicated a non-covalent interaction between dipeptidyl peptidase and trelagliptin. Altogether, potent dipeptidyl peptidase inhibitionmay partially contribute to sustained efficacy ofmore » trelagliptin.« less

Protection of MES23.5 dopaminergic cells by obestatin is mediated by proliferative rather than anti-apoptotic action.

PubMed

Shen, Xiao-Li; Jia, Feng-Ju; Song, Ning; Xie, Jun-Xia; Jiang, Hong

2014-02-01

Obestatin is an endogenous peptide sharing a precursor with ghrelin. This study aims to investigate whether and how obestatin protects MES23.5 dopaminergic cells against 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity. MES23.5 cells were pretreated with obestatin (10(-13)-10(-6) mol/L) for 20 min prior to incubation with 200 μmol/L MPP(+) for 12 or 24 h, or treated with obestatin alone (10(-13) to 10(-6) mol/L) for 0, 6, 12, and 24 h. The methyl thiazolyl tetrazolium (MTT) assay was used to measure cell viability. Flow cytometry was used to measure the caspase-3 activity and the mitochondrial transmembrane potential. Proliferating cell nuclear antigen (PCNA) protein levels were determined by Western blotting. Obestatin (10(-13) to 10(-7) mol/L) pretreatment blocked or even reversed the MPP(+)-induced reduction of viability in MES23.5 cells, but had no effect on MPP(+)-induced mitochondrial transmembrane potential collapse and caspase-3 activation. When applied alone, obestatin increased viability. Elevated PCNA levels occurred with 10(-7), 10(-9), 10(-11) and 10(-13) mol/L obestatin treatment for 12 h. The results suggest that the protective effects of obestatin against MPP(+) in MES23.5 cells are due to its proliferation-promoting rather than anti-apoptotic effects.

Liposome-based mucus-penetrating particles (MPP) for mucosal theranostics: demonstration of diamagnetic chemical exchange saturation transfer (diaCEST) magnetic resonance imaging (MRI).

PubMed

Yu, Tao; Chan, Kannie W Y; Anonuevo, Abraham; Song, Xiaolei; Schuster, Benjamin S; Chattopadhyay, Sumon; Xu, Qingguo; Oskolkov, Nikita; Patel, Himatkumar; Ensign, Laura M; van Zjil, Peter C M; McMahon, Michael T; Hanes, Justin

2015-02-01

Mucus barriers lining mucosal epithelia reduce the effectiveness of nanocarrier-based mucosal drug delivery and imaging ("theranostics"). Here, we describe liposome-based mucus-penetrating particles (MPP) capable of loading hydrophilic agents, e.g., the diaCEST MRI contrast agent barbituric acid (BA). We observed that polyethylene glycol (PEG)-coated liposomes containing ≥7 mol% PEG diffused only ~10-fold slower in human cervicovaginal mucus (CVM) compared to their theoretical speeds in water. 7 mol%-PEG liposomes contained sufficient BA loading for diaCEST contrast, and provided improved vaginal distribution compared to 0 and 3mol%-PEG liposomes. However, increasing PEG content to ~12 mol% compromised BA loading and vaginal distribution, suggesting that PEG content must be optimized to maintain drug loading and stability. Non-invasive diaCEST MRI illustrated uniform vaginal coverage and longer retention of BA-loaded 7 mol%-PEG liposomes compared to unencapsulated BA. Liposomal MPP with optimized PEG content hold promise for drug delivery and imaging at mucosal surfaces. This team of authors characterized liposome-based mucus-penetrating particles (MPP) capable of loading hydrophilic agents, such as barbituric acid (a diaCEST MRI contrast agent) and concluded that liposomal MPP with optimized PEG coating enables drug delivery and imaging at mucosal surfaces. Copyright © 2015 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLuskey, Karen; Grewal, Jaspreet S.; Das, Debanu

Clan CD cysteine peptidases, a structurally related group of peptidases that include mammalian caspases, exhibit a wide range of important functions, along with a variety of specificities and activation mechanisms. However, for the clostripain family (denoted C11), little is currently known. Here, we describe the first crystal structure of a C11 protein from the human gut bacterium, Parabacteroides merdae (PmC11), determined to 1.7-Å resolution. PmC11 is a monomeric cysteine peptidase that comprises an extended caspase-like α/β/α sandwich and an unusual C-terminal domain. It shares core structural elements with clan CD cysteine peptidases but otherwise structurally differs from the other familiesmore » in the clan. These studies also revealed a well ordered break in the polypeptide chain at Lys 147, resulting in a large conformational rearrangement close to the active site. Biochemical and kinetic analysis revealed Lys 147 to be an intramolecular processing site at which cleavage is required for full activation of the enzyme, suggesting an autoinhibitory mechanism for self-preservation. PmC11 has an acidic binding pocket and a preference for basic substrates, and accepts substrates with Arg and Lys in P1 and does not require Ca 2+ for activity. Altogether, these data provide insights into the mechanism and activity of PmC11 and a detailed framework for studies on C11 peptidases from other phylogenetic kingdoms.« less

Next Generation Sequencing Identifies Five Major Classes of Potentially Therapeutic Enzymes Secreted by Lucilia sericata Medical Maggots

PubMed Central

Franta, Zdeněk; Vogel, Heiko; Lehmann, Rüdiger; Rupp, Oliver; Goesmann, Alexander; Vilcinskas, Andreas

2016-01-01

Lucilia sericata larvae are used as an alternative treatment for recalcitrant and chronic wounds. Their excretions/secretions contain molecules that facilitate tissue debridement, disinfect, or accelerate wound healing and have therefore been recognized as a potential source of novel therapeutic compounds. Among the substances present in excretions/secretions various peptidase activities promoting the wound healing processes have been detected but the peptidases responsible for these activities remain mostly unidentified. To explore these enzymes we applied next generation sequencing to analyze the transcriptomes of different maggot tissues (salivary glands, gut, and crop) associated with the production of excretions/secretions and/or with digestion as well as the rest of the larval body. As a result we obtained more than 123.8 million paired-end reads, which were assembled de novo using Trinity and Oases assemblers, yielding 41,421 contigs with an N50 contig length of 2.22 kb and a total length of 67.79 Mb. BLASTp analysis against the MEROPS database identified 1729 contigs in 577 clusters encoding five peptidase classes (serine, cysteine, aspartic, threonine, and metallopeptidases), which were assigned to 26 clans, 48 families, and 185 peptidase species. The individual enzymes were differentially expressed among maggot tissues and included peptidase activities related to the therapeutic effects of maggot excretions/secretions. PMID:27119084

Identification of peptidases in highly pathogenic vs. weakly pathogenic Naegleria fowleri amebae.

PubMed

Vyas, Ishan K; Jamerson, Melissa; Cabral, Guy A; Marciano-Cabral, Francine

2015-01-01

Naegleria fowleri, a free-living ameba, is the causative agent of Primary Amebic Meningoencephalitis. Highly pathogenic mouse-passaged amebae (Mp) and weakly pathogenic axenically grown (Ax) N. fowleri were examined for peptidase activity. Zymography and azocasein peptidase activity assays demonstrated that Mp and Ax N. fowleri exhibited a similar peptidase pattern. Prominent for whole cell lysates, membranes and conditioned medium (CM) from Mp and Ax amebae was the presence of an activity band of approximately 58 kDa that was sensitive to E64, a cysteine peptidase inhibitor. However, axenically grown N. fowleri demonstrated a high level of this peptidase activity in membrane preparations. The inhibitor E64 also reduced peptidase activity in ameba-CM consistent with the presence of secreted cysteine peptidases. Exposure of Mp amebae to E64 reduced their migration through matrigel that was used as an extracellular matrix, suggesting a role for cysteine peptidases in invasion of the central nervous system (CNS). The collective results suggest that the profile of peptidases is not a discriminative marker for distinguishing Mp from Ax N. fowleri. However, the presence of a prominent level of activity for cysteine peptidases in N. fowleri membranes and CM, suggests that these enzymes may serve to facilitate passage of the amebae into the CNS. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

Enzymatic degradation of somatostatin by rat plasma and hypothalamus.

PubMed

Dupont, A; Alvarado-Urbina, G; Côté, J; Labrie, F

1978-10-01

A highly sensitive and specific radioimmunoassay for somatostatin has been used to study inactivation of the neurohormone by plasma and hypothalamic peptidase(s). Specificity of the inactivation process was indicated by the absence of interference by addition of luteinizing hormone releasing hormone, thyrotropin-releasing hormone, oxytocin, or substance P. The inactivating ability of hypothalamic tissue and plasma was destroyed by heating and the protease inhibitor benzamidine prevented plasma activity, thus suggesting the enzymatic nature of the processes involved. The present data suggest that the inactivation of somatostatin by hypothalamus and plasma could be an important factor in the regulation of circulating somatostatin levels.

Tripeptidyl-peptidase II: a multi-purpose peptidase.

PubMed

Tomkinson, Birgitta; Lindås, Ann-Christin

2005-10-01

Tripeptidyl-peptidase II is a high-molecular weight peptidase with a widespread distribution in eukaryotic cells. The enzyme sequentially removes tripeptides from a free N-terminus of longer peptides and also displays a low endopeptidase activity. A role for tripeptidyl-peptidase II in the formation of peptides for antigen presentation has recently become evident, and the enzyme also appears to be important for the degradation of some specific substrates, e.g. the neuropeptide cholecystokinin. However, it is likely that the main biological function of tripeptidyl-peptidase II is to participate in a general intracellular protein turnover. This peptidase may act on oligopeptides generated by the proteasome, or other endopeptidases, and the tripeptides formed would subsequently be good substrates for other exopeptidases. The fact that tripeptidyl-peptidase II activity is increased in sepsis-induced muscle wasting, a situation of enhanced protein turnover, corroborates this biological role.

Online Education in Public Affairs

ERIC Educational Resources Information Center

Ginn, Martha H.; Hammond, Augustine

2012-01-01

This exploratory study provides an overview of the current landscape of online education in the fields of Master of Public Administration and Master of Public Policy (MPA/MPP) utilizing a dataset compiled from content analysis of MPA/MPP programs' websites and survey of 96 National Association of Schools of Public Affairs and Administration…

Real-Time Embedded High Performance Computing: Communications Scheduling.

DTIC Science & Technology

1995-06-01

real - time operating system must explicitly limit the degradation of the timing performance of all processes as the number of processes...adequately supported by a real - time operating system , could compound the development problems encountered in the past. Many experts feel that the... real - time operating system support for an MPP, although they all provide some support for distributed real-time applications. A distributed real

Cysteine peptidases in the tomato trypanosomatid Phytomonas serpens: influence of growth conditions, similarities with cruzipain and secretion to the extracellular environment.

PubMed

Elias, Camila G R; Pereira, Fernanda M; Dias, Felipe A; Silva, Thiago L A; Lopes, Angela H C S; d'Avila-Levy, Claudia M; Branquinha, Marta H; Santos, André L S

2008-12-01

We have characterized the cysteine peptidase production by Phytomonas serpens, a tomato trypanosomatid. The parasites were cultivated in four distinct media, since growth conditions could modulate the synthesis of bioactive molecules. The proteolytic profile has not changed qualitatively regardless the media, showing two peptidases of 38 and 40kDa; however, few quantitative changes were observed including a drastic reduction (around 70%) on the 40 and 38kDa peptidase activities when parasites were grown in yeast extract and liver infusion trypticase medium, respectively, in comparison with parasites cultured in Warren medium. The time-span of growth did not significantly alter the protein and peptidase expression. The proteolytic activities were blocked by classical cysteine peptidase inhibitors (E-64, leupeptin, and cystatin), being more active at pH 5.0 and showing complete dependence to reducing agents (dithiothreitol and l-cysteine) for full activity. The cysteine peptidases were able to hydrolyze several proteinaceous substrates, including salivary gland proteins from Oncopeltus fasciatus, suggesting broad substrate utilization. By means of agglutination, fluorescence microscopy, flow cytometry and Western blotting analyses we showed that both cysteine peptidases produced by P. serpens share common epitopes with cruzipain, the major cysteine peptidase of Trypanosoma cruzi. Moreover, our data suggest that the 40kDa cysteine peptidase was located at the P. serpens cell surface, attached to membrane domains via a glycosylphosphatidylinositol anchor. The 40kDa peptidase was also detected in the cell-free culture supernatant, in an active form, which suggests secretion of this peptidase to the extracellular environment.

An adaptive scale factor based MPPT algorithm for changing solar irradiation levels in outer space

NASA Astrophysics Data System (ADS)

Kwan, Trevor Hocksun; Wu, Xiaofeng

2017-03-01

Maximum power point tracking (MPPT) techniques are popularly used for maximizing the output of solar panels by continuously tracking the maximum power point (MPP) of their P-V curves, which depend both on the panel temperature and the input insolation. Various MPPT algorithms have been studied in literature, including perturb and observe (P&O), hill climbing, incremental conductance, fuzzy logic control and neural networks. This paper presents an algorithm which improves the MPP tracking performance by adaptively scaling the DC-DC converter duty cycle. The principle of the proposed algorithm is to detect the oscillation by checking the sign (ie. direction) of the duty cycle perturbation between the current and previous time steps. If there is a difference in the signs then it is clear an oscillation is present and the DC-DC converter duty cycle perturbation is subsequently scaled down by a constant factor. By repeating this process, the steady state oscillations become negligibly small which subsequently allows for a smooth steady state MPP response. To verify the proposed MPPT algorithm, a simulation involving irradiances levels that are typically encountered in outer space is conducted. Simulation and experimental results prove that the proposed algorithm is fast and stable in comparison to not only the conventional fixed step counterparts, but also to previous variable step size algorithms.

Global Analysis of Photosynthesis Transcriptional Regulatory Networks

PubMed Central

Imam, Saheed; Noguera, Daniel R.; Donohue, Timothy J.

2014-01-01

Photosynthesis is a crucial biological process that depends on the interplay of many components. This work analyzed the gene targets for 4 transcription factors: FnrL, PrrA, CrpK and MppG (RSP_2888), which are known or predicted to control photosynthesis in Rhodobacter sphaeroides. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) identified 52 operons under direct control of FnrL, illustrating its regulatory role in photosynthesis, iron homeostasis, nitrogen metabolism and regulation of sRNA synthesis. Using global gene expression analysis combined with ChIP-seq, we mapped the regulons of PrrA, CrpK and MppG. PrrA regulates ∼34 operons encoding mainly photosynthesis and electron transport functions, while CrpK, a previously uncharacterized Crp-family protein, regulates genes involved in photosynthesis and maintenance of iron homeostasis. Furthermore, CrpK and FnrL share similar DNA binding determinants, possibly explaining our observation of the ability of CrpK to partially compensate for the growth defects of a ΔFnrL mutant. We show that the Rrf2 family protein, MppG, plays an important role in photopigment biosynthesis, as part of an incoherent feed-forward loop with PrrA. Our results reveal a previously unrealized, high degree of combinatorial regulation of photosynthetic genes and significant cross-talk between their transcriptional regulators, while illustrating previously unidentified links between photosynthesis and the maintenance of iron homeostasis. PMID:25503406

Global analysis of photosynthesis transcriptional regulatory networks.

PubMed

Imam, Saheed; Noguera, Daniel R; Donohue, Timothy J

2014-12-01

Photosynthesis is a crucial biological process that depends on the interplay of many components. This work analyzed the gene targets for 4 transcription factors: FnrL, PrrA, CrpK and MppG (RSP_2888), which are known or predicted to control photosynthesis in Rhodobacter sphaeroides. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) identified 52 operons under direct control of FnrL, illustrating its regulatory role in photosynthesis, iron homeostasis, nitrogen metabolism and regulation of sRNA synthesis. Using global gene expression analysis combined with ChIP-seq, we mapped the regulons of PrrA, CrpK and MppG. PrrA regulates ∼34 operons encoding mainly photosynthesis and electron transport functions, while CrpK, a previously uncharacterized Crp-family protein, regulates genes involved in photosynthesis and maintenance of iron homeostasis. Furthermore, CrpK and FnrL share similar DNA binding determinants, possibly explaining our observation of the ability of CrpK to partially compensate for the growth defects of a ΔFnrL mutant. We show that the Rrf2 family protein, MppG, plays an important role in photopigment biosynthesis, as part of an incoherent feed-forward loop with PrrA. Our results reveal a previously unrealized, high degree of combinatorial regulation of photosynthetic genes and significant cross-talk between their transcriptional regulators, while illustrating previously unidentified links between photosynthesis and the maintenance of iron homeostasis.

Differential processing of substance P and neurokinin A by plasma dipeptidyl(amino)peptidase IV, aminopeptidase M and angiotensin converting enzyme.

PubMed

Wang, L H; Ahmad, S; Benter, I F; Chow, A; Mizutani, S; Ward, P E

1991-01-01

In addition to plasma metabolism of substance P (SP) by angiotensin converting enzyme (ACE; EC 3.4.15.1) (less than 1.0 nmol/min/ml), the majority of SP hydrolysis by rat and human plasma was due to dipeptidyl(amino)peptidase IV (DAP IV; EC 3.4.14.5) (3.15-5.91 nmol/min/ml), which sequentially converted SP to SP(3-11) and SP(5-11). In turn, the SP(5-11) metabolite was rapidly hydrolyzed by rat and human plasma aminopeptidase M (AmM; EC 3.4.11.2) (24.2-25.5 nmol/min/ml). The Km values of SP for DAP IV and of SP(5-11) for AmM ranged from 32.7 to 123 microM. In contrast, neurokinin A (NKA) was resistant to both ACE and DAP IV but was subject to N-terminal hydrolysis by AmM (3.76-10.8 nmol/min/ml; Km = 90.7 microM). These data demonstrate differential processing of SP and NKA by specific peptidases in rat and human plasma.

The role of Shewanella oneidensis MR-1 outer surface structures in extracellular electron transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bouhenni, Rachida; Vora, Gary J.; Biffinger, Justin C.

2010-04-20

Shewanella oneidensis is a facultative anaerobe that uses more than 14 different terminal electron acceptors for respiration. These include metal oxides and hydroxyoxides, and toxic metals such as uranium and chromium. Mutants deficient in metal reduction were isolated using the mariner transposon derivative, minihimar RB1. These included mutants with transposon insertions in the prepilin peptidase and type II secretion system genes. All mutants were deficient in Fe(III) and Mn(IV) reduction, and exhibited slow growth when DMSO was used as the electron acceptor. The genome sequence of S. oneidensis contains one prepilin peptidase gene, pilD. A similar prepilin peptidase that maymore » function in the processing of type II secretion prepilins was not found. Single and multiple chromosomal deletions of four putative type IV pilin genes did not affect Fe(III) and Mn(IV) reduction. These results indicate that PilD in S. oneidensis is responsible for processing both type IV and type II secretion prepilin proteins. Type IV pili do not appear to be required for Fe(III) and Mn(IV) reduction.« less

Conversion-Integration of MSFC Nonlinear Signal Diagnostic Analysis Algorithms for Realtime Execution of MSFC's MPP Prototype System

NASA Technical Reports Server (NTRS)

Jong, Jen-Yi

1996-01-01

NASA's advanced propulsion system Small Scale Magnetic Disturbances/Advanced Technology Development (SSME/ATD) has been undergoing extensive flight certification and developmental testing, which involves large numbers of health monitoring measurements. To enhance engine safety and reliability, detailed analysis and evaluation of the measurement signals are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce the risk of catastrophic system failures and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. During the development of SSME, ASRI participated in the research and development of several advanced non- linear signal diagnostic methods for health monitoring and failure prediction in turbomachinery components. However, due to the intensive computational requirement associated with such advanced analysis tasks, current SSME dynamic data analysis and diagnostic evaluation is performed off-line following flight or ground test with a typical diagnostic turnaround time of one to two days. The objective of MSFC's MPP Prototype System is to eliminate such 'diagnostic lag time' by achieving signal processing and analysis in real-time. Such an on-line diagnostic system can provide sufficient lead time to initiate corrective action and also to enable efficient scheduling of inspection, maintenance and repair activities. The major objective of this project was to convert and implement a number of advanced nonlinear diagnostic DSP algorithms in a format consistent with that required for integration into the Vanderbilt Multigraph Architecture (MGA) Model Based Programming environment. This effort will allow the real-time execution of these algorithms using the MSFC MPP Prototype System. ASRI has completed the software conversion and integration of a sequence of nonlinear signal analysis techniques specified in the SOW for real-time execution on MSFC's MPP Prototype. This report documents and summarizes the results of the contract tasks; provides the complete computer source code; including all FORTRAN/C Utilities; and all other utilities/supporting software libraries that are required for operation.

Emergence of Global Shape Processing Continues through Adolescence

ERIC Educational Resources Information Center

Scherf, K. Suzanne; Behrmann, Marlene; Kimchi, Ruth; Luna, Beatriz

2009-01-01

The developmental trajectory of perceptual organization in humans is unclear. This study investigated perceptual grouping abilities across a wide age range (8-30 years) using a classic compound letter global/local (GL) task and a more fine-grained microgenetic prime paradigm (MPP) with both few- and many-element hierarchical displays. In the GL…

Association of the ACE, GSTM1, IL-6, NOS3, and CYP1A1 polymorphisms with susceptibility of mycoplasma pneumoniae pneumonia in Chinese children

PubMed Central

Zhao, Jie; Zhang, Wen; Shen, Li; Yang, Xiaomeng; Liu, Yi; Gai, Zhongtao

2017-01-01

Abstract Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP) and the clinical presentation of mycoplasma pneumoniae pneumonia (MPP) varies widely. Genetic variability affecting the host response may also influence the susceptibility to MPP. Several studies have investigated the association between single nucleotide polymorphism (SNP) of some genes and the risks of CAP; however, the results were inconsistent. Here, we investigated the association of 5 functional genes and the risks of MPP, including ACE (rs4340), GSTM1 (Ins/del), IL-6 (rs1800795), NOS3 (rs1799983), and CYP1A1 (rs2606345) in a total of 715 subjects (415 cases, 300 controls) by using tetra-primer allele-specific polymerase chain reaction (PCR) and Sanger sequencing. The gene–gene interactions were analyzed using the Multifactor Dimensionality Reduction and cumulative genetic risk score approaches. Our results showed that 3 SNPs of ACE rs4340, IL-6 rs1800795, and NOS3 rs1799983 were significantly associated with the risks of MPP, while no differences were observed in genotype frequencies of GSTM1 (Ins/del) and CYP1A1 rs2606345 between both groups. The combinations of ACE rs4340D/NOS3 rs1799983T/CYP1A1 rs2606345G and ACE rs4340D/NOS3 rs1799983T contribute to the genetic susceptibility of MPP in Chinese children. PMID:28403117

TiO2 dye sensitized solar cell (DSSC): linear relationship of maximum power point and anthocyanin concentration

NASA Astrophysics Data System (ADS)

Ahmadian, Radin

2010-09-01

This study investigated the relationship of anthocyanin concentration from different organic fruit species and output voltage and current in a TiO2 dye-sensitized solar cell (DSSC) and hypothesized that fruits with greater anthocyanin concentration produce higher maximum power point (MPP) which would lead to higher current and voltage. Anthocyanin dye solution was made with crushing of a group of fresh fruits with different anthocyanin content in 2 mL of de-ionized water and filtration. Using these test fruit dyes, multiple DSSCs were assembled such that light enters through the TiO2 side of the cell. The full current-voltage (I-V) co-variations were measured using a 500 Ω potentiometer as a variable load. Point-by point current and voltage data pairs were measured at various incremental resistance values. The maximum power point (MPP) generated by the solar cell was defined as a dependent variable and the anthocyanin concentration in the fruit used in the DSSC as the independent variable. A regression model was used to investigate the linear relationship between study variables. Regression analysis showed a significant linear relationship between MPP and anthocyanin concentration with a p-value of 0.007. Fruits like blueberry and black raspberry with the highest anthocyanin content generated higher MPP. In a DSSC, a linear model may predict MPP based on the anthocyanin concentration. This model is the first step to find organic anthocyanin sources in the nature with the highest dye concentration to generate energy.

Ameliorative effects of Qingfei Tongluo formula on experimental mycoplasmal pneumonia in mice.

PubMed

Jiang, Yong-hong; Yu, Jian-er; Guo, Ai-hua; Li, Xiao; Lin, Yan; Jiang, Zhi-yan; Xiao, Zhen

2016-04-01

Mycoplasma pneumoniae pneumonia (MPP) is a common disease in children. Qingfei Tongluo formula (QTF) has been used for the treatment of MPP clinically, but the chemical constituents and mechanism involved remain unclear. This study aimed to analyze the main chemical constituents and to explore the possible mechanism of action associated with QTF treatment of MPP. Liquid chromatography-mass spectrometry was employed to identify the compounds contained in the QTF extract. A BALB/c mouse model of MP infection was established. After treatment with QTF (0.85 and 1.70 g/kg) for 3 days, hematoxylin and eosin staining was performed in lung tissues for histological examination. Inflammatory cytokines were detected by ELISA. Western blot analysis was used for detecting phosphorylated proteins involved in MAPK and nuclear factor (NF)-κB signaling pathways. In the mouse model, a large amount of pulmonary interstitial infiltration of lymphocytes and plasmacytes were seen as well as bronchus and vasodilation congestion. Following QTF treatment, inflammation was alleviated significantly compared with the model group. Inflammatory cytokines [interleukin (IL)-6, transforming growth factor-β1, IL-8, IL-1β and tumor necrosis factor-α] in bronchoalveolar lavage fluid were decreased dramatically. In addition, we found that QTF inhibited activation of phosphorylation of JNK, ERK and NF-κB. In conclusion, QTF alleviates MPP inflammation possibly via inhibitory activation of MAPK/NF-κB pathways, which can act as a new agent for MPP treatment.

N-methyltetrahydropyridines and pyridinium cations as toxins and comparison with naturally-occurring alkaloids.

PubMed

Herraiz, Tomás

2016-11-01

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium cation (MPP + ) are selective dopaminergic neurotoxins producing Parkinsonism. MPTP is activated by monoamine oxidase-B (MAO-B) to MPP + that inhibits mitochondrial function. Molecules resembling MPTP which afford pyridinium cations are also neurotoxins. The herbicide paraquat (a bipyridinium dication) and the naturally-occurring β-carboline and isoquinoline alkaloids are structural analogues of MPTP/MPP + . Paraquat generates reactive oxygen species (ROS) producing neurotoxicity by a mechanism that differs from MPTP/MPP + . Human exposure to PQ is increasingly associated with neurodegeneration. Tetrahydro-β-carbolines (THβCs), β-carbolines (βCs) and tetrahydroisoquinolines (TIQ s ) are bioactive compounds occurring in foods and the human body. They are not MPTP-like toxins and do not appear to induce neurotoxicity at normal levels of exposure. Among TIQs, endogenous dopamine-derived TIQs (i.e. salsolinol) and 1-benzyl-TIQ are toxic through ROS generation. In contrast, β-carbolinium (βC + s) and isoquinolinium cations (IQ + s) are neurotoxicants resembling MPP + although they are less potent and selective. βC + s and IQ + s have been detected in the human brain but their toxicological significance remains unknown. THβCs/βCs and TIQs are activated to toxic cations by N-methyltransferases (NMT) and/or heme peroxidases and are metabolized by cytochrome P450 enzymes. Remarkably, recent findings suggest, instead, that βCs and TIQs are neuroprotectants and neurorestorative, raising the interest of these molecules. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neuroglobin overexpression plays a pivotal role in neuroprotection through mitochondrial raft-like microdomains in neuroblastoma SK-N-BE2 cells.

PubMed

Garofalo, Tina; Ferri, Alberto; Sorice, Maurizio; Azmoon, Pardis; Grasso, Maria; Mattei, Vincenzo; Capozzi, Antonella; Manganelli, Valeria; Misasi, Roberta

2018-04-01

Since stressing conditions induce a relocalization of endogenous human neuroglobin (NGB) to mitochondria, this research is aimed to evaluate the protective role of NGB overexpression against neurotoxic stimuli, through mitochondrial lipid raft-associated complexes. To this purpose, we built a neuronal model of oxidative stress by the use of human dopaminergic neuroblastoma cells, SK-N-BE2, stably overexpressing NGB by transfection and treated with 1-methyl-4-phenylpyridinium ion (MPP+). We preliminary observed the redistribution of NGB to mitochondria following MPP+ treatment. The analysis of mitochondrial raft-like microdomains revealed that, following MPP+ treatment, NGB translocated to raft fractions (Triton X-100-insoluble), where it interacts with ganglioside GD3. Interestingly, the administration of agents capable of perturbating microdomain before MPP+ treatment, significantly affected viability in SK-N-BE2-NGB cells. The overexpression of NGB was able to abrogate the mitochondrial injuries on complex IV activity or mitochondrial morphology induced by MPP+ administration. The protective action of NGB on mitochondria only takes place if the mitochondrial lipid(s) rafts-like microdomains are intact, indeed NGB fails to protect complex IV activity when purified mitochondria were treated with the lipid rafts disruptor methyl-β-cyclodextrin. Thus, our unique in vitro model of stably transfected cells overexpressing endogenous NGB allowed us to suggest that the role in neuroprotection played by NGB is reliable only through interaction with mitochondrial lipid raft-associated complexes. Copyright © 2018 Elsevier Inc. All rights reserved.

The epigenetic regulation of HIF-1α by SIRT1 in MPP{sup +} treated SH-SY5Y cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Su-Yan; Guo, Yan-Jie; Feng, Ya

Both silent information regulator 1 (SIRT1) and hypoxia inducible factor 1 (HIF-1) have been found to play important roles in the pathophysiology of Parkinson's disease (PD). However, their mechanisms and their relationship still require further study. In the present study, we focused on the change and relationship of SIRT1 and HIF-1α in PD. PD cell models were established by using methyl-4-phenylpyridinium (MPP{sup +}), which induced inhibition of cell proliferation, cell cycle arrest and apoptosis. We found that the expression of HIF-1α and its target genes VEGFA and LDHA increased and that SIRT1 expression was inhibited in MPP{sup +} treated cells.more » With further analysis, we found that the acetylation of H3K14 combined with the HIF-1α promoter was dramatically increased in cells treated with MPP{sup +}, which resulted in the transcriptional activation of HIF-1α. Moreover, the acetylation of H3K14 and the expression of HIF-1α increased when SIRT1 was knocked down, suggesting that SIRT1 was involved in the epigenetic regulation of HIF-1α. At last, phenformin, another mitochondrial complex1 inhibitor, was used to testify that the increased HIF-1a was not due to off target effects of MPP{sup +}. Therefore, our results support a link between PD and SIRT1/HIF-1α signaling, which may serve as a clue for understanding PD.« less

Inhibition of Protein Ubiquitination by Paraquat and 1-Methyl-4-Phenylpyridinium Impairs Ubiquitin-Dependent Protein Degradation Pathways.

PubMed

Navarro-Yepes, Juliana; Anandhan, Annadurai; Bradley, Erin; Bohovych, Iryna; Yarabe, Bo; de Jong, Annemieke; Ovaa, Huib; Zhou, You; Khalimonchuk, Oleh; Quintanilla-Vega, Betzabet; Franco, Rodrigo

2016-10-01

Intracytoplasmic inclusions of protein aggregates in dopaminergic cells (Lewy bodies) are the pathological hallmark of Parkinson's disease (PD). Ubiquitin (Ub), alpha (α)-synuclein, p62/sequestosome 1, and oxidized proteins are the major components of Lewy bodies. However, the mechanisms involved in the impairment of misfolded/oxidized protein degradation pathways in PD are still unclear. PD is linked to mitochondrial dysfunction and environmental pesticide exposure. In this work, we evaluated the effects of the pesticide paraquat (PQ) and the mitochondrial toxin 1-methyl-4-phenylpyridinium (MPP(+)) on Ub-dependent protein degradation pathways. No increase in the accumulation of Ub-bound proteins or aggregates was observed in dopaminergic cells (SK-N-SH) treated with PQ or MPP(+), or in mice chronically exposed to PQ. PQ decreased Ub protein content, but not its mRNA transcription. Protein synthesis inhibition with cycloheximide depleted Ub levels and potentiated PQ-induced cell death. The inhibition of proteasomal activity by PQ was found to be a late event in cell death progression and had neither effect on the toxicity of either MPP(+) or PQ, nor on the accumulation of oxidized sulfenylated, sulfonylated (DJ-1/PARK7 and peroxiredoxins), and carbonylated proteins induced by PQ. PQ- and MPP(+)-induced Ub protein depletion prompted the dimerization/inactivation of the Ub-binding protein p62 that regulates the clearance of ubiquitinated proteins by autophagy. We confirmed that PQ and MPP(+) impaired autophagy flux and that the blockage of autophagy by the overexpression of a dominant-negative form of the autophagy protein 5 (dnAtg5) stimulated their toxicity, but there was no additional effect upon inhibition of the proteasome. PQ induced an increase in the accumulation of α-synuclein in dopaminergic cells and membrane-associated foci in yeast cells. Our results demonstrate that the inhibition of protein ubiquitination by PQ and MPP(+) is involved in the dysfunction of Ub-dependent protein degradation pathways.

Functional characterization of the organic cation transporters (OCTs) in human airway pulmonary epithelial cells.

PubMed

Ingoglia, Filippo; Visigalli, Rossana; Rotoli, Bianca Maria; Barilli, Amelia; Riccardi, Benedetta; Puccini, Paola; Dall'Asta, Valeria

2015-07-01

Organic cation transporters (OCT1-3) mediate the transport of organic cations including inhaled drugs across the cell membrane, although their role in lung epithelium hasn't been well understood yet. We address here the expression and functional activity of OCT1-3 in human airway epithelial cells A549, Calu-3 and NCl-H441. Kinetic and inhibition analyses, employing [(3)H]1-methyl-4-phenylpyridinium (MPP+) as substrate, and the compounds quinidine, prostaglandine E2 (PGE2) and corticosterone as preferential inhibitors of OCT1, OCT2, and OCT3, respectively, have been performed. A549 cells present a robust MPP+ uptake mediated by one high-affinity component (Km~50μM) which is identifiable with OCT3. Corticosterone, indeed, completely inhibits MPP+ transport, while quinidine and PGE2 are inactive and SLC22A3/OCT3 silencing with siRNA markedly lowers MPP+ uptake. Conversely, Calu-3 exhibits both a high (Km<20μM) and a low affinity (Km>0.6mM) transport components, referable to OCT3 and OCT1, respectively, as demonstrated by the inhibition analysis performed at proper substrate concentrations and confirmed by the use of specific siRNA. These transporters are active also when cells are grown under air-liquid interface (ALI) conditions. Only a very modest saturable MPP+ uptake is measurable in NCl-H441 cells and the inhibitory effect of quinidine points to OCT1 as the subtype functionally involved in this model. Finally, the characterization of MPP+ transport in human bronchial BEAS-2B cells suggests that OCT1 and OCT3 are operative. These findings could help to identify in vitro models to be employed for studies concerning the specific involvement of each transporter in drug transportation. Copyright © 2015 Elsevier B.V. All rights reserved.

The role of glycolysis and gluconeogenesis in the cytoprotection of neuroblastoma cells against 1-methyl 4-phenylpyridinium ion toxicity.

PubMed

Mazzio, Elizabeth; Soliman, Karam F A

2003-01-01

1-Methyl-4-phenylpyridinium (MPP+) is a mitochondrial Complex I inhibitor and is frequently used to investigate the pathological degeneration of neurons associated with Parkinson's disease (PD). In vitro, extracellular concentration of glucose is one of the most critical factors in establishing the vulnerability of neurons to MPP+ toxicity. While glucose is the primary energy fuel for the brain, central nervous system (CNS) neurons can also take up and utilize other metabolic intermediates for energy. In this study, we compared various monosaccharides, disaccharides, nutritive/non-nutritive sugar alcohols, glycolytic and gluconeogenic metabolic intermediates for their cytoprotection against MPP+ in murine brain neuroblastoma cells. Several monosaccharides were effective against MMP+ (500 microM) including glucose, fructose and mannose, which restored cell viability to 109 +/- 5%, 70 +/- 5%, 99 +/- 3% of live controls, respectively. Slight protective effects were observed in the presence of 3-phosphoglyceric acid and glucose-6-phosphate; however, no protective effects were exhibited by galactose, sucrose, sorbitol, mannitol, glycerol or various gluconeogenic and ketogenic amino acids. On the other hand, fructose 1,6 bisphosphate and gluconeogenic energy intermediates [pyruvic acid, malic acid and phospho(enol)pyruvate (PEP)] were neuroprotective against MPP+. The gluconeogenic intermediates elevated intracellular levels of ATP and reduced propidium iodide (PI) nucleic acid staining to live controls, but did not alter the MPP(+)-induced loss of mitochondrial O2 consumption. These data indicate that malic acid, pyruvic acid and PEP contribute to anaerobic substrate level phosphorylation. The use of hydrazine sulfate to impede gluconeogenesis through PEP carboxykinase (PEPCK) inhibition heightened the protective effects of energy substrates possibly due to attenuated ATP demands from pyruvate carboxylase (PC) activity and pyruvate mitochondrial transport. It was concluded from these studies that several metabolic intermediates are effective in fueling anaerobic glycolysis during mitochondrial inhibition by MPP+.

Mitochondrial inhibitor models of Huntington's disease and Parkinson's disease induce zinc accumulation and are attenuated by inhibition of zinc neurotoxicity in vitro or in vivo.

PubMed

Sheline, Christian T; Zhu, Julia; Zhang, Wendy; Shi, Chunxiao; Cai, Ai-Li

2013-01-01

Inhibition of mitochondrial function occurs in many neurodegenerative diseases, and inhibitors of mitochondrial complexes I and II are used to model them. The complex II inhibitor, 3-nitroproprionic acid (3-NPA), kills the striatal neurons susceptible in Huntington's disease. The complex I inhibitor N-methyl-4-phenylpyridium (MPP(+)) and 6-hydroxydopamine (6-OHDA) are used to model Parkinson's disease. Zinc (Zn(2+)) accumulates after 3-NPA, 6-OHDA and MPP(+) in situ or in vivo. We will investigate the role of Zn(2+) neurotoxicity in 3-NPA, 6-OHDA and MPP(+). Murine striatal/midbrain tyrosine hydroxylase positive, or near-pure cortical neuronal cultures, or animals were exposed to 3-NPA or MPP(+) and 6-OHDA with or without neuroprotective compounds. Intracellular zinc ([Zn(2+)](i)), nicotinamide adenine dinucleotide (NAD(+)), NADH, glycolytic intermediates and neurotoxicity were measured. We showed that compounds or genetics which restore NAD(+) and attenuate Zn(2+) neurotoxicity (pyruvate, nicotinamide, NAD(+), increased NAD(+) synthesis, sirtuin inhibition or Zn(2+) chelation) attenuated the neuronal death induced by these toxins. The increase in [Zn(2+)](i) preceded a reduction in the NAD(+)/NADH ratio that caused a reversible glycolytic inhibition. Pyruvate, nicotinamide and NAD(+) reversed the reductions in the NAD(+)/NADH ratio, glycolysis and neuronal death after challenge with 3-NPA, 6-OHDA or MPP(+), as was previously shown for exogenous Zn(2+). To test efficacy in vivo, we injected 3-NPA into the striatum of rats and systemically into mice, with or without pyruvate. We observed early striatal Zn(2+) fluorescence, and pyruvate significantly attenuated the 3-NPA-induced lesion and restored behavioral scores. Together, these studies suggest that Zn(2+) accumulation caused by MPP(+) and 3-NPA is a novel preventable mechanism of the resultant neurotoxicity. Copyright © 2012 S. Karger AG, Basel.

Down-regulation of natural resistance-associated macrophage protein-1 (Nramp1) is associated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/1-methyl-4-phenylpyridinium (MPP+ )-induced α-synuclein accumulation and neurotoxicity.

PubMed

Wu, K-C; Liou, H-H; Lee, C-Y; Lin, C-J

2018-04-21

The accumulation of α-synuclein is a hallmark in the pathogenesis of Parkinson's disease (PD). Natural resistance-associated macrophage protein-1 (Nramp1) was previously shown to contribute to the degradation of extracellular α-synuclein in microglia under conditions of iron overload. This study was aimed at investigating the role of Nramp1 in α-synuclein pathology in the neurone under 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/1-methyl-4-phenylpyridinium (MPP + ) treatment. The expression of Nramp1 and pathological features (including iron and α-synuclein accumulation) were examined in the dopaminergic neurones of humans (with and without PD) and of mice [with and without receiving chronic MPTP intoxication]. The effects of Nramp1 expression on low-dose MPP + -induced α-synuclein expression and neurotoxicity were determined in human dopaminergic neuroblastoma SH-SY5Y cells. Similar to the findings in the substantia nigra of human PD, lower expression of Nramp1 but higher levels of iron and α-synuclein were identified in the dopaminergic neurones of mice receiving chronic MPTP intoxication, compared to controls. In parallel to the loss of dopaminergic neurones, the numbers of glial fibrillary acidic protein- and ionized calcium-binding adapter molecule-1-positive cells were significantly increased in the substantia nigra of MPTP-treated mice. Likewise, in human neuroblastoma SH-SY5Y cells exposed to low-dose MPP + , Nramp1 expression and cathepsin D activity were decreased, along with an increase in α-synuclein protein expression and aggregation. Overexpression of functional Nramp1 restored cathepsin D activity and attenuated α-synuclein up-regulation and neuronal cell death caused by MPP + treatment. These data suggest that the neuronal expression of Nramp1 is important for protecting against the development of MPTP/MPP + -induced α-synuclein pathology and neurotoxicity. © 2018 British Neuropathological Society.

Medicinal herbs Oenanthe javanica (Blume) DC., Casuarina equisetifolia L. and Sorghum bicolor (L.) Moench protect human cells from MPP+ damage via inducing FBXO7 expression.

PubMed

Chen, Chiung-Mei; Chen, I-Cheng; Chen, Ying-Lin; Lin, Te-Hsien; Chen, Wan-Ling; Chao, Chih-Ying; Wu, Yih-Ru; Lu, Yeah-Ting; Lee, Cheng-Yu; Chien, Hong-Chi; Chen, Ting-Shou; Lee-Chen, Guey-Jen; Lee, Chi-Mei

2016-11-15

The F-box protein 7 (FBXO7) mutations have been identified in families with early-onset parkinsonism and pyramidal tract signs, and designated as PARK15. In addition, FBXO7 mutations were found in typical and young onset Parkinson's disease (PD). Evidence has also shown that FBXO7 plays an important role in the development of dopaminergic neurons and increased stability and overexpression of FBXO7 may be beneficial to PD. We screened extracts of medicinal herbs to enhance FBXO7 expression for neuroprotection in MPP + -treated cells. Promoter reporter assay in HEK-293 cells was used to examine the cis/trans elements controlling FBXO7 expression and to screen extracts of medicinal herbs enhancing FBXO7 expression. MTT assay was performed to assess cell viability of MPP + -treated HEK-293/SH-SY5Y cells. In addition, proteasome activity, mitochondrial membrane potential and FBXO7/TRAF2/GATA2 protein expression were evaluated. We demonstrated that -202--57 region of the FBXO7 promoter is likely to contain sequences that are bound by positive trans protein factors to activate FBXO7 expression and GATA2 is the main trans protein factor enhancing FBXO7 expression. Extracts of medicinal herbs Oenanthe javanica (Blume) DC. (Umbelliferae), Casuarina equisetifolia L. (Casuarinaceae), and Sorghum bicolor (L.) Moench (Gramineae) improved cell viability of both MPP + -treated HEK-293 and SH-SY5Y cells, rescued proteasome activity in MPP + -treated HEK-293 cells, and restored mitochondrial membrane potential in MPP + -treated SH-SY5Y cells. These protection effects of herbal extracts are acting through enhancing FBXO7 and decreasing TRAF2 expression, which is probably mediated by GATA2 induction. Collectively, our study provides new targets, FBXO7 and its regulator GATA2, for the development of potential treatments of PD. Copyright © 2016 Elsevier GmbH. All rights reserved.

Estimation of the effects of multipoint pacing on battery longevity in routine clinical practice.

PubMed

Akerström, Finn; Narváez, Irene; Puchol, Alberto; Pachón, Marta; Martín-Sierra, Cristina; Rodríguez-Mañero, Moisés; Rodríguez-Padial, Luis; Arias, Miguel A

2017-09-23

Multipoint pacing (MPP) permits simultaneous multisite pacing of the left ventricle (LV); initial studies suggest haemodynamic and clinical benefits over conventional (single LV site) cardiac resynchronization therapy (CRT). The aim of this study was to estimate the impact of MPP activation on battery longevity in routine clinical practice. Patient (n = 46) and device data were collected from two centres at least 3 months after MPP-CRT device implantation. Multipoint pacing programming was based on the maximal possible anatomical LV1/LV2 separation according to three predefined LV pacing capture threshold (PCT) cut-offs (≤1.5 V; ≤4.0 V; and ≤6.5 V). Estimated battery longevity was calculated using the programmed lower rate limit, lead impedances, outputs, and pacing percentages. Relative to the longevity for conventional CRT using the lowest PCT (8.9 ± 1.2 years), MPP activation significantly shortened battery longevity for all three PCT cut-offs (≤1.5 V, -5.6%; ≤4.0 V, -16.9%; ≤6.5 V, -21.3%; P's <0.001). When compared with conventional CRT based on longest right ventricle-LV delay (8.3 ± 1.3 years), battery longevity was significantly shortened for the MPP ≤ 4.0 V and ≤6.5 V cut-offs (-10.8 and -15.7%, respectively; P's <0.001). Maximal LV1/LV2 spacing was possible in 23.9% (≤1.5 V), 56.5% (≤4.0 V), and 69.6% (≤6.5 V) of patients. Multipoint pacing activation significantly reduces battery longevity compared with that for conventional CRT configuration. When reasonable MPP LV vector PCTs (≤4.0 V) are achieved, the decrease in battery longevity is relatively small which may prompt the clinician to activate MPP. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Inhibition of protein ubiquitination by paraquat and 1-methyl-4-phenylpyridinium impairs ubiquitin-dependent protein degradation pathways

PubMed Central

Navarro-Yepes, Juliana; Anandhan, Annadurai; Bradley, Erin; Bohovych, Iryna; Yarabe, Bo; de Jong, Annemieke; Ovaa, Huib; Zhou, You; Khalimonchuk, Oleh; Quintanilla-Vega, Betzabet; Franco, Rodrigo

2016-01-01

Intracytoplasmic inclusions of protein aggregates in dopaminergic cells (Lewy bodies) are the pathological hallmark of Parkinson’s disease (PD). Ubiquitin (Ub), alpha [α]-synuclein, p62/sequestosome 1 and oxidized proteins are major components of Lewy bodies. However, the mechanisms involved in the impairment of misfolded/oxidized protein degradation pathways in PD are still unclear. PD is linked to mitochondrial dysfunction and environmental pesticide exposure. In this work, we evaluated the effect of the pesticide paraquat (PQ) and the mitochondrial toxin 1-methyl-4-phenylpyridinium (MPP+) on Ub-dependent protein degradation pathways. No increase in the accumulation of Ub-bound proteins or aggregates was observed in dopaminergic cells (SK-N-SH) treated with PQ or MPP+, or in mice chronically exposed to PQ. PQ decreased Ub protein content, but not its mRNA transcription. Protein synthesis inhibition with cycloheximide depleted Ub levels and potentiated PQ–induced cell death. Inhibition of proteasomal activity by PQ was found to be a late event in cell death progression, and had no effect on either the toxicity of MPP+ or PQ, or the accumulation of oxidized sulfenylated, sulfonylated (DJ-1/PARK7 and peroxiredoxins) and carbonylated proteins induced by PQ. PQ- and MPP+-induced Ub protein depletion prompted the dimerization/inactivation of the Ub-binding protein p62 that regulates the clearance of ubiquitinated proteins by autophagic. We confirmed that PQ and MPP+ impaired autophagy flux, and that the blockage of autophagy by the overexpression of a dominant-negative form of the autophagy protein 5 (dnAtg5) stimulated their toxicity, but there was no additional effect upon inhibition of the proteasome. PQ induced an increase in the accumulation of α-synuclein in dopaminergic cells and membrane associated foci in yeast cells. Our results demonstrate that inhibition of protein ubiquitination by PQ and MPP+ is involved in the dysfunction of Ub-dependent protein degradation pathways. PMID:26409479

Characterization and inhibition of a cholecystokinin-inactivating serine peptidase.

PubMed

Rose, C; Vargas, F; Facchinetti, P; Bourgeat, P; Bambal, R B; Bishop, P B; Chan, S M; Moore, A N; Ganellin, C R; Schwartz, J C

1996-04-04

A cholecystokinin (CCK)-inactivating peptidase was purified and identified as a membrane-bound isoform of tripeptidyl peptidase II (EC 3.4.14.10), a cytosolic subtilisin-like peptidase of previously unknown functions. The peptidase was found in neurons responding to cholecystokinin, as well as in non-neuronal cells. Butabindide, a potent and specific inhibitor, was designed and shown to protect endogenous cholecystokinin from inactivation and to display pro-satiating effects mediated by the CCKA receptor.

Bioinformatic analysis of the neprilysin (M13) family of peptidases reveals complex evolutionary and functional relationships

PubMed Central

2008-01-01

Background The neprilysin (M13) family of endopeptidases are zinc-metalloenzymes, the majority of which are type II integral membrane proteins. The best characterised of this family is neprilysin, which has important roles in inactivating signalling peptides involved in modulating neuronal activity, blood pressure and the immune system. Other family members include the endothelin converting enzymes (ECE-1 and ECE-2), which are responsible for the final step in the synthesis of potent vasoconstrictor endothelins. The ECEs, as well as neprilysin, are considered valuable therapeutic targets for treating cardiovascular disease. Other members of the M13 family have not been functionally characterised, but are also likely to have biological roles regulating peptide signalling. The recent sequencing of animal genomes has greatly increased the number of M13 family members in protein databases, information which can be used to reveal evolutionary relationships and to gain insight into conserved biological roles. Results The phylogenetic analysis successfully resolved vertebrate M13 peptidases into seven classes, one of which appears to be specific to mammals, and insect genes into five functional classes and a series of expansions, which may include inactive peptidases. Nematode genes primarily resolved into groups containing no other taxa, bar the two nematode genes associated with Drosophila DmeNEP1 and DmeNEP4. This analysis reconstructed only one relationship between chordate and invertebrate clusters, that of the ECE sub-group and the DmeNEP3 related genes. Analysis of amino acid utilisation in the active site of M13 peptidases reveals a basis for their biochemical properties. A relatively invariant S1' subsite gives the majority of M13 peptidases their strong preference for hydrophobic residues in P1' position. The greater variation in the S2' subsite may be instrumental in determining the specificity of M13 peptidases for their substrates and thus allows M13 peptidases to fulfil a broad range of physiological roles. Conclusion The M13 family of peptidases have diversified extensively in all species examined, indicating wide ranging roles in numerous physiological processes. It is predicted that differences in the S2' subsite are fundamental to determining the substrate specificities that facilitate this functional diversity. PMID:18215274

Effects of cannabinoids Δ(9)-tetrahydrocannabinol, Δ(9)-tetrahydrocannabinolic acid and cannabidiol in MPP+ affected murine mesencephalic cultures.

PubMed

Moldzio, Rudolf; Pacher, Thomas; Krewenka, Christopher; Kranner, Barbara; Novak, Johannes; Duvigneau, Johanna Catharina; Rausch, Wolf-Dieter

2012-06-15

Cannabinoids derived from Cannabis sativa demonstrate neuroprotective properties in various cellular and animal models. Mitochondrial impairment and consecutive oxidative stress appear to be major molecular mechanisms of neurodegeneration. Therefore we studied some major cannabinoids, i.e. delta-9-tetrahydrocannabinolic acid (THCA), delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in mice mesencephalic cultures for their protective capacities against 1-methyl-4-phenyl pyridinium (MPP(+)) toxicity. MPP(+) is an established model compound in the research of parkinsonism that acts as a complex I inhibitor of the mitochondrial respiratory chain, resulting in excessive radical formation and cell degeneration. MPP(+) (10 μM) was administered for 48 h at the 9th DIV with or without concomitant cannabinoid treatment at concentrations ranging from 0.01 to 10 μM. All cannabinoids exhibited in vitro antioxidative action ranging from 669 ± 11.1 (THC), 16 ± 3.2 (THCA) to 356 ± 29.5 (CBD) μg Trolox (a vitamin E derivative)/mg substance in the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) assay. Cannabinoids were without effect on the morphology of dopaminergic cells stained by tyrosine hydroxylase (TH) immunoreaction. THC caused a dose-dependent increase of cell count up to 17.3% at 10 μM, whereas CBD only had an effect at highest concentrations (decrease of cell count by 10.1-20% at concentrations of 0.01-10 μM). It influenced the viability of the TH immunoreactive neurons significantly, whereas THCA exerts no influence on dopaminergic cell count. Exposure of cultures to 10 μM of MPP(+) for 48 h significantly decreased the number of TH immunoreactive neurons by 44.7%, and shrunken cell bodies and reduced neurite lengths could be observed. Concomitant treatment of cultures with cannabinoids rescued dopaminergic cells. Compared to MPP(+) treated cultures, THC counteracted toxic effects in a dose-dependent manner. THCA and CBD treatment at a concentration of 10 μM lead to significantly increased cell counts to 123% and 117%, respectively. Even though no significant preservation or recovery of neurite outgrowth to control values could be observed, our data show that cannabinoids THC and THCA protect dopaminergic neurons against MPP(+) induced cell death. Copyright © 2012 Elsevier GmbH. All rights reserved.

The Evaluation of HOMER as a Marine Corps Expeditionary Energy Predeployment Tool

DTIC Science & Technology

2010-09-01

experiment was used to ensure the HOMER models were accurate. Following the calibration, the concept of expeditionary energy density as it pertains to power ...Brigade–Afghanistan xvi MEP Mobile Electric Power MPP Maximum Power Point MPPT Maximum Power Point Tracker NASA National Aeronautics and...process was used to analyze HOMER’s modeling capability: • Conduct photovoltaic (PV) experiment, • Develop a calibration process to match the HOMER

The Evaluation of HOMER as a Marine Corps Expeditionary Energy Pre-deployment Tool

DTIC Science & Technology

2010-11-21

used to ensure the HOMER models were accurate. Following the calibration, the concept of expeditionary energy density as it pertains to power ...MEP Mobile Electric Power MPP Maximum Power Point MPPT Maximum Power Point Tracker NASA National Aeronautics and Space Administration...process was used to analyze HOMER’s modeling capability: • Conduct photovoltaic (PV) experiment, • Develop a calibration process to match the HOMER

Bioassay-guided Isolation of Neuroprotective Fatty Acids from Nigella sativa against 1-methyl-4-phenylpyridinium-induced Neurotoxicity

PubMed Central

Hosseinzadeh, Leila; Monaghash, Hoda; Ahmadi, Farahnaz; Ghiasvand, Nastaran; Shokoohinia, Yalda

2017-01-01

Objective: Parkinson's disease, a slowly progressive neurological disease, is associated with degeneration of the basal ganglia of the brain and a deficiency of the neurotransmitter dopamine. The main aspects of researches are the protection of normal neurons against degeneration. Fatty acids (FAs), the key structural elements of dietary lipids, are carboxylic straight chains and notable parameters in nutritional and industrial usefulness of a plant. Materials and Methods: Black cumin, a popular anti-inflammatory and antioxidant food seasoning, contains nonpolar constituents such as FAs which were extracted using hexane. Different fractions and subfractions were apt to cytoprotection against apoptosis and inflammation induced by 1-methyl-4-phenylpyridinium (MPP+) in rat pheochromocytoma cell line (PC12) as a neural cell death model. The experiment consisted of examination of cell viability assessment, mitochondrial membrane potential (MMP), caspase-3 and -9 activity, and measurement of cyclooxygenase (COX) activity. Results: MPP+ induced neurotoxicity in PC12 cells. Pretreatment with subfractions containing FA mixtures attenuated MPP+-mediated apoptosis partially dependent on the inhibition of caspase-3 and -9 activity and increasing the MMP. A mixture of linoleic acid, oleic acid, and palmitic acid also decreased the COX activity induced by MPP+ in PC12 cells. Conclusion: Our observation indicated that subtoxic concentration of FA from Nigella sativa may exert cytoprotective effects through their anti-apoptotic and anti-inflammation actions and could be regarded as a dietary supplement. SUMMARY MPP+ induced neurotoxicity in PC12 cellsNigella sativa contains bioactive fatty acidsPretreatment with fatty acids attenuated MPP+ mediated apoptosis through inhibition of caspase 3 and 9 activityA mixture of linoleic acid, oleic acid, and palmitic acid decreased the COX activity induced by MPP+ in PC12 cellsDue to cytoprotective, anti apoptotic and anti inflammation actions of N. sativa, it could be regarded as a dietary supplement. Abbreviations used: ANOVA: Analysis of variance; Ca: Calcium; CDCl3: Chloroform; COX: Cyclooxygenase; DMSO: Dimethyl sulfoxide; EA: Elidic acid; EDTA: Ethylene diamine tetraacetic acid; ELISA: Enzyme Linked Immunosorbent Assay; ESI-MS: Electron spray mass spectroscopy; FAs: Fatty acids; FBS: Fetal bovine serum; GC: Gas chromatography; 1HNMR: Hydrogen nuclear magnetic resonance; LA: Linoleic acid; MPP+: 1-Methyl-4-phenylpyridinium; MPTP: 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine; MTT: 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide; N. sativa: Nigella sativa; OA: Oleic acid; PA: Palmitic acid; PBS: Phosphate buffer saline; PC12: Rat pheochromocytoma cell line; PD: Parkinson's disease; PDA: Photo diode array detector; PGE2: Prostaglandin E2; TLC: Thin layer chromatography; TMPD: N,N,N’,N’-tetramethyl-p-phenylenediamine; USA: United states of America. PMID:29200724

Molecular Analysis of Phr Peptide Processing in Bacillus subtilis†

PubMed Central

Stephenson, Sophie; Mueller, Christian; Jiang, Min; Perego, Marta

2003-01-01

In Bacillus subtilis, an export-import pathway regulates production of the Phr pentapeptide inhibitors of Rap proteins. Processing of the Phr precursor proteins into the active pentapeptide form is a key event in the initiation of sporulation and competence development. The PhrA (ARNQT) and PhrE (SRNVT) peptides inhibit the RapA and RapE phosphatases, respectively, whose activity is directed toward the Spo0F∼P intermediate response regulator of the sporulation phosphorelay. The PhrC (ERGMT) peptide inhibits the RapC protein acting on the ComA response regulator for competence with regard to DNA transformation. The structural organization of PhrA, PhrE, and PhrC suggested a role for type I signal peptidases in the processing of the Phr preinhibitor, encoded by the phr genes, into the proinhibitor form. The proinhibitor was then postulated to be cleaved to the active pentapeptide inhibitor by an additional enzyme. In this report, we provide evidence that Phr preinhibitor proteins are subject to only one processing event at the peptide bond on the amino-terminal end of the pentapeptide. This processing event is most likely independent of type I signal peptidase activity. In vivo and in vitro analyses indicate that none of the five signal peptidases of B. subtilis (SipS, SipT, SipU, SipV, and SipW) are indispensable for Phr processing. However, we show that SipV and SipT have a previously undescribed role in sporulation, competence, and cell growth. PMID:12897006

Molecular analysis of Phr peptide processing in Bacillus subtilis.

PubMed

Stephenson, Sophie; Mueller, Christian; Jiang, Min; Perego, Marta

2003-08-01

In Bacillus subtilis, an export-import pathway regulates production of the Phr pentapeptide inhibitors of Rap proteins. Processing of the Phr precursor proteins into the active pentapeptide form is a key event in the initiation of sporulation and competence development. The PhrA (ARNQT) and PhrE (SRNVT) peptides inhibit the RapA and RapE phosphatases, respectively, whose activity is directed toward the Spo0F approximately P intermediate response regulator of the sporulation phosphorelay. The PhrC (ERGMT) peptide inhibits the RapC protein acting on the ComA response regulator for competence with regard to DNA transformation. The structural organization of PhrA, PhrE, and PhrC suggested a role for type I signal peptidases in the processing of the Phr preinhibitor, encoded by the phr genes, into the proinhibitor form. The proinhibitor was then postulated to be cleaved to the active pentapeptide inhibitor by an additional enzyme. In this report, we provide evidence that Phr preinhibitor proteins are subject to only one processing event at the peptide bond on the amino-terminal end of the pentapeptide. This processing event is most likely independent of type I signal peptidase activity. In vivo and in vitro analyses indicate that none of the five signal peptidases of B. subtilis (SipS, SipT, SipU, SipV, and SipW) are indispensable for Phr processing. However, we show that SipV and SipT have a previously undescribed role in sporulation, competence, and cell growth.

The Challenge of Creating a More Diverse Economics: Lessons from the UCR Minority Pipeline Project

ERIC Educational Resources Information Center

Dymski, Gary A.

2017-01-01

This paper reflects on the experience of the 1999-2002 minority pipeline program (MPP) at the University of California, Riverside. With support from the American Economic Association, the MPP identified students of color interested in economics, let them explore economic issues affecting minority communities, and encouraged them to consider…

Maximum power point tracking algorithm based on sliding mode and fuzzy logic for photovoltaic sources under variable environmental conditions

NASA Astrophysics Data System (ADS)

Atik, L.; Petit, P.; Sawicki, J. P.; Ternifi, Z. T.; Bachir, G.; Della, M.; Aillerie, M.

2017-02-01

Solar panels have a nonlinear voltage-current characteristic, with a distinct maximum power point (MPP), which depends on the environmental factors, such as temperature and irradiation. In order to continuously harvest maximum power from the solar panels, they have to operate at their MPP despite the inevitable changes in the environment. Various methods for maximum power point tracking (MPPT) were developed and finally implemented in solar power electronic controllers to increase the efficiency in the electricity production originate from renewables. In this paper we compare using Matlab tools Simulink, two different MPP tracking methods, which are, fuzzy logic control (FL) and sliding mode control (SMC), considering their efficiency in solar energy production.

Phytomonas serpens: immunological similarities with the human trypanosomatid pathogens.

PubMed

Santos, André L S; d'Avila-Levy, Claudia M; Elias, Camila G R; Vermelho, Alane B; Branquinha, Marta H

2007-07-01

The present review provides an overview of recent discoveries concerning the immunological similarities between Phytomonas serpens, a tomato parasite, and human trypanosomatid pathogens, with special emphasis on peptidases. Leishmania spp. and Trypanosoma cruzi express peptidases that are well-known virulence factors, named leishmanolysin and cruzipain. P. serpens synthesizes two distinct classes of proteolytic enzymes, metallo- and cysteine-type peptidases, that share common epitopes with leishmanolysin and cruzipain, respectively. The leishmanolysin-like and cruzipain-like molecules from P. serpens participate in several biological processes including cellular growth and adhesion to the salivary glands of Oncopeltus fasciatus, a phytophagous insect experimental model. Since previous reports demonstrated that immunization of mice with P. serpens induced a partial protective immune response against T. cruzi, this plant trypanosomatid may be a suitable candidate for vaccine studies. Moreover, comparative approaches in the Trypanosomatidae family may be useful to understand kinetoplastid biology, biochemistry and evolution.

Mast Cell Peptidases

PubMed Central

Trivedi, Neil N.; Caughey, George H.

2010-01-01

Mast cells make and secrete an abundance of peptidases, which are stored in such large amounts in granules that they comprise a high fraction of all cellular protein. Perhaps no other immune cell is so generously endowed with peptidases. For many years after the main peptidases were first described, they were best known as markers of degranulation, for they are released locally in response to mast cell stimulation and can be distributed systemically and detected in blood. The principal peptidases are tryptases, chymases, carboxypeptidase A3, and dipeptidylpeptidase I (cathepsin C). Numerous studies suggest that these enzymes are important and even critical for host defense and homeostasis. Endogenous and allergen or pathogen-associated targets have been identified. Belying the narrow notion of peptidases as proinflammatory, several of the peptidases limit inflammation and toxicity of endogenous peptides and venoms. The peptidases are interdependent, so that absence or inactivity of one enzyme can alter levels and activity of others. Mammalian mast cell peptidases—chymases and tryptases especially—vary remarkably in number, expression, biophysical properties, and specificity, perhaps because they hyper-evolved under pressure from the very pathogens they help to repel. Tryptase and chymase involvement in some pathologies stimulated development of therapeutic inhibitors for use in asthma, lung fibrosis, pulmonary hypertension, ulcerative colitis, and cardiovascular diseases. While animal studies support the potential for mast cell peptidase inhibitors to mitigate certain diseases, other studies, as in mice lacking selected peptidases, predict roles in defense against bacteria and parasites and that systemic inactivation may impair host defense. PMID:19933375

Dipeptidyl peptidase IV, aminopeptidase N and DPIV/APN-like proteases in cerebral ischemia

PubMed Central

2012-01-01

Background Cerebral inflammation is a hallmark of neuronal degeneration. Dipeptidyl peptidase IV, aminopeptidase N as well as the dipeptidyl peptidases II, 8 and 9 and cytosolic alanyl-aminopeptidase are involved in the regulation of autoimmunity and inflammation. We studied the expression, localisation and activity patterns of these proteases after endothelin-induced occlusion of the middle cerebral artery in rats, a model of transient and unilateral cerebral ischemia. Methods Male Sprague-Dawley rats were used. RT-PCR, immunohistochemistry and protease activity assays were performed at different time points, lasting from 2 h to 7 days after cerebral ischemia. The effect of protease inhibitors on ischemia-dependent infarct volumes was quantified 7 days post middle cerebral artery occlusion. Statistical analysis was conducted using the t-test. Results Qualitative RT-PCR revealed these proteases in ipsilateral and contralateral cortices. Dipeptidyl peptidase II and aminopeptidase N were up-regulated ipsilaterally from 6 h to 7 days post ischemia, whereas dipeptidyl peptidase 9 and cytosolic alanyl-aminopeptidase were transiently down-regulated at day 3. Dipeptidyl peptidase 8 and aminopeptidase N immunoreactivities were detected in cortical neurons of the contralateral hemisphere. At the same time point, dipeptidyl peptidase IV, 8 and aminopeptidase N were identified in activated microglia and macrophages in the ipsilateral cortex. Seven days post artery occlusion, dipeptidyl peptidase IV immunoreactivity was found in the perikarya of surviving cortical neurons of the ipsilateral hemisphere, whereas their nuclei were dipeptidyl peptidase 8- and amino peptidase N-positive. At the same time point, dipeptidyl peptidase IV, 8 and aminopeptidase N were targeted in astroglial cells. Total dipeptidyl peptidase IV, 8 and 9 activities remained constant in both hemispheres until day 3 post experimental ischemia, but were increased (+165%) in the ipsilateral cortex at day 7. In parallel, aminopeptidase N and cytosolic alanyl-aminopeptidase activities remained unchanged. Conclusions Distinct expression, localization and activity patterns of proline- and alanine-specific proteases indicate their involvement in ischemia-triggered inflammation and neurodegeneration. Consistently, IPC1755, a non-selective protease inhibitor, revealed a significant reduction of cortical lesions after transient cerebral ischemia and may suggest dipeptidyl peptidase IV, aminopeptidase N and proteases with similar substrate specificity as potentially therapy-relevant targets. PMID:22373413

Structure and function studies on enzymes with a catalytic carboxyl group(s): from ribonuclease T1 to carboxyl peptidases

PubMed Central

TAKAHASHI, Kenji

2013-01-01

A group of enzymes, mostly hydrolases or certain transferases, utilize one or a few side-chain carboxyl groups of Asp and/or Glu as part of the catalytic machinery at their active sites. This review follows mainly the trail of studies performed by the author and his colleagues on the structure and function of such enzymes, starting from ribonuclease T1, then extending to three major types of carboxyl peptidases including aspartic peptidases, glutamic peptidases and serine-carboxyl peptidases. PMID:23759941

Peptidomics methods for the identification of peptidase-substrate interactions

PubMed Central

Lone, Anna Mari; Kim, Yun-Gon; Saghatelian, Alan

2013-01-01

Peptidases have important roles in controlling physiological signaling through their regulation of bioactive peptides. Understanding and controlling bioactive peptide regulation is of great biomedical interest and approaches that elucidate the interplay between peptidases and their substrates are vital for achieving this goal. Here, we highlight the utility of recent peptidomics approaches in identifying endogenous substrates of peptidases. These approaches reveal bioactive substrates and help characterize the biochemical functions of the enzyme. Most recently, peptidomics approaches have been applied to address the challenging question of identifying the peptidases responsible for regulating specific bioactive peptides. Since peptidases are of great biomedical interest, these approaches will begin to impact our ability to identify new drug targets that regulate important bioactive peptides. PMID:23332665

Vascular niche promotes hematopoietic multipotent progenitor formation from pluripotent stem cells

PubMed Central

Gori, Jennifer L.; Butler, Jason M.; Chan, Yan-Yi; Chandrasekaran, Devikha; Poulos, Michael G.; Ginsberg, Michael; Nolan, Daniel J.; Elemento, Olivier; Wood, Brent L.; Adair, Jennifer E.; Rafii, Shahin; Kiem, Hans-Peter

2015-01-01

Pluripotent stem cells (PSCs) represent an alternative hematopoietic stem cell (HSC) source for treating hematopoietic disease. The limited engraftment of human PSC–derived (hPSC-derived) multipotent progenitor cells (MPP) has hampered the clinical application of these cells and suggests that MPP require additional cues for definitive hematopoiesis. We hypothesized that the presence of a vascular niche that produces Notch ligands jagged-1 (JAG1) and delta-like ligand-4 (DLL4) drives definitive hematopoiesis. We differentiated hes2 human embryonic stem cells (hESC) and Macaca nemestrina–induced PSC (iPSC) line-7 with cytokines in the presence or absence of endothelial cells (ECs) that express JAG1 and DLL4. Cells cocultured with ECs generated substantially more CD34+CD45+ hematopoietic progenitors compared with cells cocultured without ECs or with ECs lacking JAG1 or DLL4. EC-induced cells exhibited Notch activation and expressed HSC-specific Notch targets RUNX1 and GATA2. EC-induced PSC-MPP engrafted at a markedly higher level in NOD/SCID/IL-2 receptor γ chain–null (NSG) mice compared with cytokine-induced cells, and low-dose chemotherapy-based selection further increased engraftment. Long-term engraftment and the myeloid-to-lymphoid ratio achieved with vascular niche induction were similar to levels achieved for cord blood–derived MPP and up to 20-fold higher than those achieved with hPSC-derived MPP engraftment. Our findings indicate that endothelial Notch ligands promote PSC-definitive hematopoiesis and production of long-term engrafting CD34+ cells, suggesting these ligands are critical for HSC emergence. PMID:25664855

DNA damage tolerance in hematopoietic stem and progenitor cells in mice

PubMed Central

Pilzecker, Bas; Buoninfante, Olimpia Alessandra; van den Berk, Paul; Lancini, Cesare; Song, Ji-Ying; Citterio, Elisabetta

2017-01-01

DNA damage tolerance (DDT) enables bypassing of DNA lesions during replication, thereby preventing fork stalling, replication stress, and secondary DNA damage related to fork stalling. Three modes of DDT have been documented: translesion synthesis (TLS), template switching (TS), and repriming. TLS and TS depend on site-specific PCNA K164 monoubiquitination and polyubiquitination, respectively. To investigate the role of DDT in maintaining hematopoietic stem cells (HSCs) and progenitors, we used PcnaK164R/K164R mice as a unique DDT-defective mouse model. Analysis of the composition of HSCs and HSC-derived multipotent progenitors (MPPs) revealed a significantly reduced number of HSCs, likely owing to increased differentiation of HSCs toward myeloid/erythroid-associated MPP2s. This skewing came at the expense of the number of lymphoid-primed MPP4s, which appeared to be compensated for by increased MPP4 proliferation. Furthermore, defective DDT decreased the numbers of MPP-derived common lymphoid progenitor (CLP), common myeloid progenitor (CMP), megakaryocyte-erythroid progenitor (MEP), and granulocyte-macrophage progenitor (GMP) cells, accompanied by increased cell cycle arrest in CMPs. The HSC and MPP phenotypes are reminiscent of premature aging and stressed hematopoiesis, and indeed progressed with age and were exacerbated on cisplatin exposure. Bone marrow transplantations revealed a strong cell intrinsic defect of DDT-deficient HSCs in reconstituting lethally irradiated mice and a strong competitive disadvantage when cotransplanted with wild-type HSCs. These findings indicate a critical role of DDT in maintaining HSCs and progenitor cells, and in preventing premature aging. PMID:28761001

Silibinin attenuates MPP⁺-induced neurotoxicity in the substantia nigra in vivo.

PubMed

Jung, Un Ju; Jeon, Min-Tae; Choi, Myung-Sook; Kim, Sang Ryong

2014-05-01

Parkinson's disease (PD) is characterized by degeneration of the nigrostriatal dopaminergic (DA) pathway. The cause of neuronal death in PD is largely unknown, but it is becoming clear that inflammation plays a significant role in the pathophysiology of PD. Silibinin is a major flavonoid in milk thistle which has an anti-inflammatory activity. We investigated whether silibinin could have neuroprotective effects on DA neurons in the 1-methyl-4-phenylpyridinium ion (MPP(+))-treated animal model of PD in vivo. To address this question, animals received intraperitoneal (i.p.) injections 10, 50, or 100 mg/kg of silibinin, starting 1 day before MPP(+) injection and continued daily until 6 days post-lesion for tyrosine hydroxylase (TH) staining, or until 1 hour prior to the MPP(+) injection to examine the expression levels of inflammatory proteins. Finally, their brains were harvested at the indicated time points for the analyses. Silibinin treatment with 10 mg/kg had no significantly neuroprotective effects in the substantia nigra (SN). However, 50 and 100 mg/kg of silibinin ameliorated the MPP(+)-induced neurotoxicity in the SN in a dose-dependent manner, and the increased levels of inflammatory molecules such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) by MPP(+) treatment were attenuated by treatment with 100 mg/kg of silibinin. These results indicate that silibinin could be a useful and beneficial natural product offering promise for the prevention of DA neuronal degeneration involved in PD.

[Changes of masseter muscle asymmetry due to unilateral mastication after intervention: a electromyographic analysis].

PubMed

Wang, Yun; Teng, Chen; Wang, Meng-Ya

2015-04-01

To explore the effect of intervention with unilateral mastication on masseter muscle asymmetry. Forty-three subjects (19 males and 24 females, mean age 20.0∓0.5 years) with unilateral chewing were divided into group A0 with motivation and without intervention, group A1 with motivation and intervention, group B0 without motivation or intervention, and group B1 without motivation but with intervention. In groups A0 and A1, the motivation was removed and groups A1 and group B1 received interventions. Surface electromyography was recorded using surface electromyography in all the subjects in mandible postural position (MPP), with maximum clenching in intercuspal position (ICP) and during chewing. The sEMG of the left and right masseter muscle were separately recorded to assess the asymmetry index of the masseter muscles (ASMM) and its changes after intervention. In groupA0, the ASMM at MPP, during maximum clenching and chewing had no obvious changes after removal of the motivation. In group A1, the ASMM at MPP, during maximum clenching and chewing were obviously decreased after intervention. In group B0, the ASMM at MPP and during maximum clenching showed no obvious changes but ASMM during chewing significantly increased after removal of the motivation. In group B1, the ASMM at MPP, during maximum clenching and chewing all decreased obviously after intervention. Interventions can significantly improve the bilateral symmetry of the masseter muscles in subjects with unilateral chewing, and the motivation for unilateral chewing should be removed before intervention.

Protection against MPP(+)-induced neurotoxicity in SH-SY5Y cells by tormentic acid via the activation of PI3-K/Akt/GSK3β pathway.

PubMed

Zhao, Qing; Ye, Junli; Wei, Na; Fong, Chichun; Dong, Xiaoli

2016-07-01

The cause of Parkinson's disease (PD) could be ascribed to the progressive and selective loss of dopaminergic neurons in the substantia nigra pars compacta, and thus molecules with neuroprotective ability may have therapeutic value against PD. In the current study, the neuroprotective effects and underlying mechanisms of tormentic acid (TA), a naturally occurring triterpene extracted from medicinal plants such as Rosa rugosa and Potentilla chinensis, were evaluated in a widely used cellular PD model in which neurotoxicity was induced by MPP(+) in cultured SH-SY5Y cells. We found that TA at 1-30 μM substantially protected against MPP(+)-induced neurotoxicity, as evidenced by the increase in cell viability, decrease in lactate dehydrogenase release and the reduction in apoptotic nuclei. Moreover, TA effectively inhibited the elevated intracellular accumulation of reactive oxygen species as well as Bax/Bcl-2 ratio caused by MPP(+). Most importantly, TA markedly reversed the inhibition of protein expression of phosphorylated Akt (Ser 473) and phosphorylated GSK3β (Ser 9) caused by MPP(+). LY294002, the specific inhibitor of PI3-K, significantly abrogated the up-regulated phosphorylated Akt and phosphorylated GSK3β offered by TA, suggesting that the neuroprotection of TA was mainly dependent on the activation of PI3-K/Akt/GSK3β signaling pathway. The results taken together indicate that TA may be a potential candidate for further preclinical study aimed at the prevention and treatment of PD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of surface chemistry on nanoparticle interaction with gastrointestinal mucus and distribution in the gastrointestinal tract following oral and rectal administration in the mouse.

PubMed

Maisel, Katharina; Ensign, Laura; Reddy, Mihika; Cone, Richard; Hanes, Justin

2015-01-10

It is believed that mucoadhesive surface properties on particles delivered to the gastrointestinal (GI) tract improve oral absorption or local targeting of various difficult-to-deliver drug classes. To test the effect of nanoparticle mucoadhesion on distribution of nanoparticles in the GI tract, we orally and rectally administered nano- and microparticles that we confirmed possessed surfaces that were either strongly mucoadhesive or non-mucoadhesive. We found that mucoadhesive particles (MAP) aggregated in mucus in the center of the GI lumen, far away from the absorptive epithelium, both in healthy mice and in a mouse model of ulcerative colitis (UC). In striking contrast, water absorption by the GI tract rapidly and uniformly transported non-mucoadhesive mucus-penetrating particles (MPP) to epithelial surfaces, including reaching the surfaces between villi in the small intestine. When using high gavage fluid volumes or injection into ligated intestinal loops, common methods for assessing oral drug and nanoparticle absorption, we found that both MAP and MPP became well-distributed throughout the intestine, indicating that the barrier properties of GI mucus were compromised. In the mouse colorectum, MPP penetrated into mucus in the deeply in-folded surfaces to evenly coat the entire epithelial surface. Moreover, in a mouse model of UC, MPP were transported preferentially into the disrupted, ulcerated tissue. Our results suggest that delivering drugs in non-mucoadhesive MPP is likely to provide enhanced particle distribution, and thus drug delivery, in the GI tract, including to ulcerated tissues. Copyright © 2014 Elsevier B.V. All rights reserved.

Acetyl-L-carnitine prevents total body hydroxyl free radical and uric acid production induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the rat.

PubMed

Loots, Du Toit; Mienie, Lodewyk J; Bergh, Jacobus J; Van der Schyf, Cornelis J

2004-07-23

Acetyl-L-carnitine (ALCAR) is intimately involved in the transport of long chain fatty acids across the inner mitochondrial membrane during oxidative phosphorylation. ALCAR also has been reported to attenuate the occurrence of parkinsonian symptoms associated with 1-methyl-1,2,3,6-tetrahydropyridine (MPTP) in vivo, and protects in vitro against the toxicity of the neurotoxic 1-methyl-4-phenylpyridinium (MPP+) metabolite of MPTP. The mechanism for these protective effects remains unclear. ALCAR may attenuate hydroxyl (HO*) free radical production in the MPTP/MPP+ neurotoxic pathway through several mechanisms. Most studies on MPTP/MPP+ toxicity and protection by ALCAR have focused on in vivo brain chemistry and in vitro neuronal culture studies. The present study investigates the attenuative effects of ALCAR on whole body oxidative stress markers in the urine of rats treated with MPTP. In a first study, ALCAR totally prevented the MPTP-induced formation of HO* measured by salicylate radical trapping. In a second study, the production of uric acid after MPTP administration-a measure of oxidative stress mediated through xanthine oxidase-was also prevented by ALCAR. Because ALCAR is unlikely to be a potent radical scavenger, these studies suggest that ALCAR protects against MPTP/MPP+-mediated oxidative stress through other mechanisms. We speculate that ALCAR may operate through interference with organic cation transporters such as OCTN2 and/or carnitine-acylcarnitine translocase (CACT), based partly on the above findings and on semi-empirical electronic similarity calculations on ALCAR, MPP+, and two other substrates for these transporters.

Organize or Die: Farm School Pedagogy and the Political Ecology of the Agroecological Transition in Rural Haiti

ERIC Educational Resources Information Center

Moore, Sophie Sapp

2017-01-01

This article examines the political and pedagogical role of the farm school in Haiti's largest and oldest peasants' movement, the Peasants' Movement of Papaye (MPP). It draws upon ongoing ethnographic research with MPP as well as documentary and historical analyses of agrarian politics in Haiti to situate the movement's land-based decolonial…

Alterations in bioenergetic function induced by Parkinson's disease mimetic compounds: Lack of correlation with superoxide generation

PubMed Central

Dranka, Brian P.; Zielonka, Jacek; Kanthasamy, Anumantha G.; Kalyanaraman, Balaraman

2012-01-01

In vitro and in vivo models of Parkinson's disease (PD) suggest that increased oxidant production leads to mitochondrial dysfunction in dopaminergic neurons and subsequent cell death. However, it remains unclear if cell death in these models is caused by inhibition of mitochondrial function or oxidant production. The objective of the present study was to determine the relationship between mitochondrial dysfunction and oxidant production in response to multiple PD neurotoxicant mimetics. MPP+ caused a dose-dependent decrease in the basal oxygen consumption rate (OCR) in dopaminergic N27 cells, indicating a loss of mitochondrial function. In parallel, we found that MPP+ only modestly increased oxidation of hydroethidine as a diagnostic marker of superoxide production in these cells. Similar results were found using rotenone as a mitochondrial inhibitor, or 6-hydroxydopamine as a mechanistically distinct PD neurotoxicant, but not with exposure to paraquat. Additionally, the Extracellular Acidification Rate, used as a marker of glycolysis, was stimulated to compensate for OCR inhibition after exposure to MPP+, rotenone, or 6-hydroxydopamine, but not paraquat. Together these data indicate that MPP+, rotenone and 6-hydroxydopamine dramatically shift bioenergetic function away from the mitochondria and towards glycolysis in N27 cells. PMID:22708893

Anti-diabetic effect of dietary mango (Mangifera indica L.) peel in streptozotocin-induced diabetic rats.

PubMed

Gondi, Mahendranath; Basha, Shaik Akbar; Bhaskar, Jamuna J; Salimath, Paramahans V; Rao, Ummiti J S Prasada

2015-03-30

In the present study, the composition of mango peel powder (MPP) collected from the mango pulp industry was determined and the effect of MPP on ameliorating diabetes and its associated complications was studied. Mango peel was rich in polyphenols, carotenoids and dietary fibre. Peel extract contained various bioactive compounds and was found to be rich in soluble dietary fibre. Peel extract exhibited antioxidant properties and protected against DNA damage. Therefore, the effect of peel on ameliorating diabetes was investigated in a rat model of diabetes. A significant increase in urine sugar, urine volume, fasting blood glucose, total cholesterol, triglycerides and low density lipoprotein, and decrease in high density lipoprotein were observed in the rats; however, these parameters were ameliorated in diabetic rats fed with diet supplemented with mango peel at 5% and 10% levels in basal diet. Treatment of diabetic rats with MPP increased antioxidant enzyme activities and decreased lipid peroxidation in plasma, kidney and liver compared to untreated diabetic rats. Glomerular filtration rate and microalbuminuria levels were ameliorated in MPP treated diabetic group. Mango peel, a by-product, can be used as an ingredient in functional and therapeutic foods. © 2014 Society of Chemical Industry.

Sound absorption of microperforated panels inside compact acoustic enclosures

NASA Astrophysics Data System (ADS)

Yang, Cheng; Cheng, Li

2016-01-01

This paper investigates the sound absorption effect of microperforated panels (MPPs) in small-scale enclosures, an effort stemming from the recent interests in using MPPs for noise control in compact mechanical systems. Two typical MPP backing cavity configurations (an empty backing cavity and a honeycomb backing structure) are studied. Although both configurations provide basically the same sound absorption curves from standard impedance tube measurements, their in situ sound absorption properties, when placed inside a small enclosure, are drastically different. This phenomenon is explained using a simple system model based on modal analyses. It is shown that the accurate prediction of the in situ sound absorption of the MPPs inside compact acoustic enclosures requires meticulous consideration of the configuration of the backing cavity and its coupling with the enclosure in front. The MPP structure should be treated as part of the entire system, rather than an absorption boundary characterized by the surface impedance, calculated or measured in simple acoustic environment. Considering the spatial matching between the acoustic fields across the MPP, the possibility of attenuating particular enclosure resonances by partially covering the enclosure wall with a properly designed MPP structure is also demonstrated.

WldS but not Nmnat1 protects dopaminergic neurites from MPP+ neurotoxicity.

PubMed

Antenor-Dorsey, Jo Ann V; O'Malley, Karen L

2012-02-08

The WldS mouse mutant ("Wallerian degeneration-slow") delays axonal degeneration in a variety of disorders including in vivo models of Parkinson's disease. The mechanisms underlying WldS -mediated axonal protection are unclear, although many studies have attributed WldS neuroprotection to the NAD+-synthesizing Nmnat1 portion of the fusion protein. Here, we used dissociated dopaminergic cultures to test the hypothesis that catalytically active Nmnat1 protects dopaminergic neurons from toxin-mediated axonal injury. Using mutant mice and lentiviral transduction of dopaminergic neurons, the present findings demonstrate that WldS but not Nmnat1, Nmnat3, or cytoplasmically-targeted Nmnat1 protects dopamine axons from the parkinsonian mimetic N-methyl-4-phenylpyridinium (MPP+). Moreover, NAD+ synthesis is not required since enzymatically-inactive WldS still protects. In addition, NAD+ by itself is axonally protective and together with WldS is additive in the MPP+ model. Our data suggest that NAD+ and WldS act through separate and possibly parallel mechanisms to protect dopamine axons. As MPP+ is thought to impair mitochondrial function, these results suggest that WldS might be involved in preserving mitochondrial health or maintaining cellular metabolism.

Inhibitors of tripeptidyl peptidase II. 2. Generation of the first novel lead inhibitor of cholecystokinin-8-inactivating peptidase: a strategy for the design of peptidase inhibitors.

PubMed

Ganellin, C R; Bishop, P B; Bambal, R B; Chan, S M; Law, J K; Marabout, B; Luthra, P M; Moore, A N; Peschard, O; Bourgeat, P; Rose, C; Vargas, F; Schwartz, J C

2000-02-24

The cholecystokinin-8 (CCK-8)-inactivating peptidase is a serine peptidase which has been shown to be a membrane-bound isoform of tripeptidyl peptidase II (EC 3.4.14.10). It cleaves the neurotransmitter CCK-8 sulfate at the Met-Gly bond to give Asp-Tyr(SO(3)H)-Met-OH + Gly-Trp-Met-Asp-Phe-NH(2). In seeking a reversible inhibitor of this peptidase, the enzymatic binding subsites were characterized using a fluorimetric assay based on the hydrolysis of the artificial substrate Ala-Ala-Phe-amidomethylcoumarin. A series of di- and tripeptides having various alkyl or aryl side chains was studied to determine the accessible volume for binding and to probe the potential for hydrophobic interactions. From this initial study the tripeptides Ile-Pro-Ile-OH (K(i) = 1 microM) and Ala-Pro-Ala-OH (K(i) = 3 microM) and dipeptide amide Val-Nvl-NHBu (K(i) = 3 microM) emerged as leads. Comparison of these structures led to the synthesis of Val-Pro-NHBu (K(i) = 0.57 microM) which served for later optimization in the design of butabindide, a potent reversible competitive and selective inhibitor of the CCK-8-inactivating peptidase. The strategy for this work is explicitly described since it illustrates a possible general approach for peptidase inhibitor design.

Evaluation of the catalytic specificity, biochemical properties, and milk clotting abilities of an aspartic peptidase from Rhizomucor miehei.

PubMed

da Silva, Ronivaldo Rodrigues; Souto, Tatiane Beltramini; de Oliveira, Tássio Brito; de Oliveira, Lilian Caroline Gonçalves; Karcher, Daniel; Juliano, Maria Aparecida; Juliano, Luiz; de Oliveira, Arthur H C; Rodrigues, André; Rosa, Jose C; Cabral, Hamilton

2016-08-01

In this study, we detail the specificity of an aspartic peptidase from Rhizomucor miehei and evaluate the effects of this peptidase on clotting milk using the peptide sequence of k-casein (Abz-LSFMAIQ-EDDnp) and milk powder. Molecular mass of the peptidase was estimated at 37 kDa, and optimum activity was achieved at pH 5.5 and 55 °C. The peptidase was stable at pH values ranging from 3 to 5 and temperatures of up 45 °C for 60 min. Dramatic reductions in proteolytic activity were observed with exposure to sodium dodecyl sulfate, and aluminum and copper (II) chloride. Peptidase was inhibited by pepstatin A, and mass spectrometry analysis identified four peptide fragments (TWSISYGDGSSASGILAK, ASNGGGGEYIFGGYDSTK, GSLTTVPIDNSR, and GWWGITVDRA), similar to rhizopuspepsin. The analysis of catalytic specificity showed that the coagulant activity of the peptidase was higher than the proteolytic activity and that there was a preference for aromatic, basic, and nonpolar amino acids, particularly methionine, with specific cleavage of the peptide bond between phenylalanine and methionine. Thus, this peptidase may function as an important alternative enzyme in milk clotting during the preparation of cheese.

Selected missense mutations impair frataxin processing in Friedreich ataxia.

PubMed

Clark, Elisia; Butler, Jill S; Isaacs, Charles J; Napierala, Marek; Lynch, David R

2017-08-01

Frataxin (FXN) is a highly conserved mitochondrial protein. Reduced FXN levels cause Friedreich ataxia, a recessive neurodegenerative disease. Typical patients carry GAA repeat expansions on both alleles, while a subgroup of patients carry a missense mutation on one allele and a GAA repeat expansion on the other. Here, we report that selected disease-related FXN missense mutations impair FXN localization, interaction with mitochondria processing peptidase, and processing. Immunocytochemical studies and subcellular fractionation were performed to study FXN import into the mitochondria and examine the mechanism by which mutations impair FXN processing. Coimmunoprecipitation was performed to study the interaction between FXN and mitochondrial processing peptidase. A proteasome inhibitor was used to model traditional therapeutic strategies. In addition, clinical profiles of subjects with and without point mutations were compared in a large natural history study. FXN I 154F and FXN G 130V missense mutations decrease FXN 81-210 levels compared with FXN WT , FXN R 165C , and FXN W 155R , but do not block its association with mitochondria. FXN I 154F and FXN G 130V also impair FXN maturation and enhance the binding between FXN 42-210 and mitochondria processing peptidase. Furthermore, blocking proteosomal degradation does not increase FXN 81-210 levels. Additionally, impaired FXN processing also occurs in fibroblasts from patients with FXN G 130V . Finally, clinical data from patients with FXN G 130V and FXN I 154F mutations demonstrates a lower severity compared with other individuals with Friedreich ataxia. These data suggest that the effects on processing associated with FXN G 130V and FXN I 154F mutations lead to higher levels of partially processed FXN, which may contribute to the milder clinical phenotypes in these patients.

Axonal transports of tripeptidyl peptidase II in rat sciatic nerves.

PubMed

Chikuma, Toshiyuki; Shimizu, Maki; Tsuchiya, Yukihiro; Kato, Takeshi; Hojo, Hiroshi

2007-01-01

Axonal transport of tripeptidyl peptidase II, a putative cholecystokinin inactivating serine peptidase, was examined in the proximal, middle, and distal segments of rat sciatic nerves using a double ligation technique. Enzyme activity significantly increased not only in the proximal segment but also in the distal segment 12-72h after ligation, and the maximal enzyme activity was found in the proximal and distal segments at 72h. Western blot analysis of tripeptidyl peptidase II showed that its immunoreactivities in the proximal and distal segments were 3.1- and 1.7-fold higher than that in the middle segment. The immunohistochemical analysis of the segments also showed an increase in immunoreactive tripeptidyl peptidase II level in the proximal and distal segments in comparison with that in the middle segment, indicating that tripeptidyl peptidase II is transported by anterograde and retrograde axonal flow. The results suggest that tripeptidyl peptidase II may be involved in the metabolism of neuropeptides in nerve terminals or synaptic clefts.

Crystal and Solution Structures of a Prokaryotic M16B Peptidase: an Open and Shut Case

PubMed Central

Aleshin, Alexander E.; Gramatikova, Svetlana; Hura, Gregory L.; Bobkov, Andrey; Strongin, Alex Y.; Stec, Boguslaw; Tainer, John A.; Liddington, Robert C.; Smith, Jeffrey W.

2013-01-01

SUMMARY The M16 family of zinc peptidases comprises a pair of homologous domains that form two halves of a ‘‘clam-shell’’ surrounding the active site. The M16A and M16C subfamilies form one class (‘‘peptidasomes’’): they degrade 30–70 residue peptides, and adopt both open and closed conformations. The eukaryotic M16B subfamily forms a second class (‘‘processing proteases’’): they adopt a single partly-open conformation that enables them to cleave signal sequences from larger proteins. Here, we report the solution and crystal structures of a prokaryotic M16B peptidase, and demonstrate that it has features of both classes: thus, it forms stable ‘‘open’’ homodimers in solution that resemble the processing proteases; but the clam-shell closes upon binding substrate, a feature of the M16A/C peptidasomes. Moreover, clam-shell closure is required for proteolytic activity. We predict that other prokaryotic M16B family members will form dimeric peptidasomes, and propose a model for the evolution of the M16 family. PMID:19913481

Blocking the proliferation of human tumor cell lines by peptidase inhibitors from Bauhinia seeds.

PubMed

Nakahata, Adriana Miti; Mayer, Barbara; Neth, Peter; Hansen, Daiane; Sampaio, Misako Uemura; Oliva, Maria Luiza Vilela

2013-03-01

In cancer tumors, growth, invasion, and formation of metastasis at a secondary site play a pivotal role, participating in diverse processes in the development of the pathology, such as degradation of extracellular matrix. Bauhinia seeds contain relatively large quantities of peptidase inhibitors, and two Bauhinia inhibitors were obtained in a recombinant form from the Bauhinia bauhinioides species, B. bauhinoides cruzipain inhibitor, which is a cysteine and serine peptidase inhibitor, and B. bauhinioides kallikrein inhibitor, which is a serine peptidase inhibitor. While recombinant B. bauhinoides cruzipain inhibitor inhibits human neutrophil elastase cathepsin G and the cysteine proteinase cathepsin L, recombinant B. bauhinioides kallikrein inhibitor inhibits plasma kallikrein and plasmin. The effects of recombinant B. bauhinoides cruzipain inhibitor and recombinant B. bauhinioides kallikrein inhibitor on the viability of tumor cell lines with a distinct potential of growth from the same tissue were compared to those of the clinical cytotoxic drug 5-fluorouracil. At 12.5 µM concentration, recombinant B. bauhinoides cruzipain inhibitor and recombinant B. bauhinioides kallikrein inhibitor were more efficient than 5-fluorouracil in inhibiting MKN-28 and Hs746T (gastric), HCT116 and HT29 (colorectal), SkBr-3 and MCF-7 (breast), and THP-1 and K562 (leukemia) cell lines. Additionally, recombinant B. bauhinoides cruzipain inhibitor inhibited 40 % of the migration of Hs746T, the most invasive gastric cell line, while recombinant B. bauhinioides kallikrein inhibitor did not affect cell migration. Recombinant B. bauhinioides kallikrein inhibitor and recombinant B. bauhinoides cruzipain inhibitor, even at high doses, did not affect hMSC proliferation while 5-fluorouracil greatly reduced the proliferation rates of hMSCs. Therefore, both recombinant B. bauhinoides cruzipain inhibitor and recombinant B. bauhinioides kallikrein inhibitor might be considered for further studies to block peptidase activities in order to target specific peptidase-mediated growth and invasion characteristics of individual tumors, mainly in patients resistant to 5-fluorouracil chemotherapy. Georg Thieme Verlag KG Stuttgart · New York.

Characterizations of a synthetic pituitary adenylate cyclase-activating polypeptide analog displaying potent neuroprotective activity and reduced in vivo cardiovascular side effects in a Parkinson's disease model.

PubMed

Lamine, Asma; Létourneau, Myriam; Doan, Ngoc Duc; Maucotel, Julie; Couvineau, Alain; Vaudry, Hubert; Chatenet, David; Vaudry, David; Fournier, Alain

2016-09-01

Parkinson's disease (PD) is characterized by a steady loss of dopamine neurons through apoptotic, inflammatory and oxidative stress processes. In that line of view, the pituitary adenylate cyclase-activating polypeptide (PACAP), with its ability to cross the blood-brain barrier and its anti-apoptotic, anti-inflammatory and anti-oxidative properties, has proven to offer potent neuroprotection in various PD models. Nonetheless, its peripheral actions, paired with low metabolic stability, hampered its clinical use. We have developed Ac-[Phe(pI)(6), Nle(17)]PACAP(1-27) as an improved PACAP-derived neuroprotective compound. In vitro, this analog stimulated cAMP production, maintained mitochondrial potential and protected SH-SY5Y neuroblastoma cells from 1-methyl-4-phenylpyridinium (MPP(+)) toxicity, as potently as PACAP. Furthermore, contrasting with PACAP, it is stable in human plasma and against dipeptidyl peptidase IV activity. When injected intravenously to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, PACAP and Ac-[Phe(pI)(6), Nle(17)]PACAP(1-27) restored tyrosine hydoxylase expression into the substantia nigra and modulated the inflammatory response. Albeit falls of mean arterial pressure (MAP) were observed with both PACAP- and Ac-[Phe(pI)(6), Nle(17)]PACAP(1-27)-treated mice, the intensity of the decrease as well as its duration were significantly less marked after iv injections of the analog than after those of the native polypeptide. Moreover, no significant changes in heart rate were measured with the animals for both compounds. Thus, Ac-[Phe(pI)(6), Nle(17)]PACAP(1-27) appears as a promising lead molecule for the development of PACAP-derived drugs potentially useful for the treatment of PD or other neurodegenerative diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

The general mitochondrial processing peptidase from potato is an integral part of cytochrome c reductase of the respiratory chain.

PubMed Central

Braun, H P; Emmermann, M; Kruft, V; Schmitz, U K

1992-01-01

The major mitochondrial processing activity removing presequences from nuclear encoded precursor proteins is present in the soluble fraction of fungal and mammalian mitochondria. We found that in potato, this activity resides in the inner mitochondrial membrane. Surprisingly, the proteolytic activity co-purifies with cytochrome c reductase, a protein complex of the respiratory chain. The purified complex is bifunctional, as it has the ability to transfer electrons from ubiquinol to cytochrome c and to cleave off the presequences of mitochondrial precursor proteins. In contrast to the nine subunit fungal complex, cytochrome c reductase from potato comprises 10 polypeptides. Protein sequencing of peptides from individual subunits and analysis of corresponding cDNA clones reveals that subunit III of cytochrome c reductase (51 kDa) represents the general mitochondrial processing peptidase. Images PMID:1324169

Effects of a Pre-workout Supplement on Lean Mass, Muscular Performance, Subjective Workout Experience and Biomarkers of Safety

PubMed Central

Kedia, A. William; Hofheins, Jennifer E.; Habowski, Scott M.; Ferrando, Arny A.; Gothard, M. David; Lopez, Hector L.

2014-01-01

In this prospective, randomized, double-blind, trial conducted in two parts, we examined the effects of a multi-ingredient pre-exercise workout supplement blend of creatine, betaine and a dendrobium extract (MMP) on safety, performance, and body composition in healthy men and women undergoing a supervised program of resistance exercise. Part 1 was an acute hemodynamic safety study wherein forty young, healthy men and women (26.2 ± 5.3 years, 70.4 ± 3.3 inches, 83.7 ± 14.9 kg, 26.0 ± 3.2 kg●m-2) ingest one dose of either the MMP or comparator in a randomized, double-blind, comparator controlled, crossover fashion before having their resting heart rate, blood, ECG and comprehensive blood chemistry and blood counts completed. Systolic (SBP) and diastolic (DBP) blood pressures were generally raised (3.0-5.4 mm Hg, p<0.01) following supplementation with MPP whereas in the comparator group SBP was marginally reduced by 0.3 to 1.2 mm Hg, p>0.05 at all time points) and DBP was increased (3.0 - 3.9 mm Hg, p<0.05 at all time points). No changes in EKG-corrected QT interval were observed, and no serious adverse events were reported. Part 2 was a six-week training study wherein forty-three young, healthy men and women (24.3 ± 2.9 years, 70.5 ± 3.1 inches, 83.8 ± 9.6 kg, 26.1 ± 2.7 kg●m-2) supplemented with daily pre-workout doses of either the MPP or a comparator in a randomized, double-blind, comparator-controlled fashion while following a standardized resistance training program for six weeks. MPP and the comparator were isocaloric and delivered the same amount of caffeine. Significant improvements in visual analog scale (VAS) scores for energy (p<0.024) and concentration (p<0.041) were found along with consistently higher levels of focus accompanied by less fatigue when MPP was consumed in comparison to comparator during upper body muscular strength-endurance tests at weeks 3 and 6. MPP supplementation for 6 weeks did not improve dual-energy x-ray absorptiometry (DEXA) measures of body composition or objective assessments of exercise performance. Overall, MPP use and administration was well tolerated. Self-reported scores for energy and concentration were significantly greater. Over a six-week training and supplementation period, MPP use was not associated with improvements in performance or body composition. Future studies should confirm these effects over a more prolonged training period. PMID:24465156

Effects of a pre-workout supplement on lean mass, muscular performance, subjective workout experience and biomarkers of safety.

PubMed

Kedia, A William; Hofheins, Jennifer E; Habowski, Scott M; Ferrando, Arny A; Gothard, M David; Lopez, Hector L

2014-01-01

In this prospective, randomized, double-blind, trial conducted in two parts, we examined the effects of a multi-ingredient pre-exercise workout supplement blend of creatine, betaine and a dendrobium extract (MMP) on safety, performance, and body composition in healthy men and women undergoing a supervised program of resistance exercise. Part 1 was an acute hemodynamic safety study wherein forty young, healthy men and women (26.2 ± 5.3 years, 70.4 ± 3.3 inches, 83.7 ± 14.9 kg, 26.0 ± 3.2 kg●m(-2)) ingest one dose of either the MMP or comparator in a randomized, double-blind, comparator controlled, crossover fashion before having their resting heart rate, blood, ECG and comprehensive blood chemistry and blood counts completed. Systolic (SBP) and diastolic (DBP) blood pressures were generally raised (3.0-5.4 mm Hg, p<0.01) following supplementation with MPP whereas in the comparator group SBP was marginally reduced by 0.3 to 1.2 mm Hg, p>0.05 at all time points) and DBP was increased (3.0 - 3.9 mm Hg, p<0.05 at all time points). No changes in EKG-corrected QT interval were observed, and no serious adverse events were reported. Part 2 was a six-week training study wherein forty-three young, healthy men and women (24.3 ± 2.9 years, 70.5 ± 3.1 inches, 83.8 ± 9.6 kg, 26.1 ± 2.7 kg●m(-2)) supplemented with daily pre-workout doses of either the MPP or a comparator in a randomized, double-blind, comparator-controlled fashion while following a standardized resistance training program for six weeks. MPP and the comparator were isocaloric and delivered the same amount of caffeine. Significant improvements in visual analog scale (VAS) scores for energy (p<0.024) and concentration (p<0.041) were found along with consistently higher levels of focus accompanied by less fatigue when MPP was consumed in comparison to comparator during upper body muscular strength-endurance tests at weeks 3 and 6. MPP supplementation for 6 weeks did not improve dual-energy x-ray absorptiometry (DEXA) measures of body composition or objective assessments of exercise performance. Overall, MPP use and administration was well tolerated. Self-reported scores for energy and concentration were significantly greater. Over a six-week training and supplementation period, MPP use was not associated with improvements in performance or body composition. Future studies should confirm these effects over a more prolonged training period.

Peptidases released by necrotic cells control CD8+ T cell cross-priming

PubMed Central

Gamrekelashvili, Jaba; Kapanadze, Tamar; Han, Miaojun; Wissing, Josef; Ma, Chi; Jaensch, Lothar; Manns, Michael P.; Armstrong, Todd; Jaffee, Elizabeth; White, Ayla O.; Citrin, Deborah E.; Korangy, Firouzeh; Greten, Tim F.

2013-01-01

Cross-priming of CD8+ T cells and generation of effector immune responses is pivotal for tumor immunity as well as for successful anticancer vaccination and therapy. Dead and dying cells produce signals that can influence Ag processing and presentation; however, there is conflicting evidence regarding the immunogenicity of necrotic cell death. We used a mouse model of sterile necrosis, in which mice were injected with sterile primary necrotic cells, to investigate a role of these cells in priming of CD8+ T cells. We discovered a molecular mechanism operating in Ag donor cells that regulates cross-priming of CD8+ T cells during primary sterile necrosis and thereby controls adaptive immune responses. We found that the cellular peptidases dipeptidyl peptidase 3 (DPP-3) and thimet oligopeptidase 1 (TOP-1), both of which are present in nonimmunogenic necrotic cells, eliminated proteasomal degradation products and blocked Ag cross-presentation. While sterile necrotic tumor cells failed to induce CD8+ T cell responses, their nonimmunogenicity could be reversed in vitro and in vivo by inactivation of DPP-3 and TOP-1. These results indicate that control of cross-priming and thereby immunogenicity of primary sterile necrosis relies on proteasome-dependent oligopeptide generation and functional status of peptidases in Ag donor cells. PMID:24216478

Peptidases released by necrotic cells control CD8+ T cell cross-priming.

PubMed

Gamrekelashvili, Jaba; Kapanadze, Tamar; Han, Miaojun; Wissing, Josef; Ma, Chi; Jaensch, Lothar; Manns, Michael P; Armstrong, Todd; Jaffee, Elizabeth; White, Ayla O; Citrin, Deborah E; Korangy, Firouzeh; Greten, Tim F

2013-11-01

Cross-priming of CD8+ T cells and generation of effector immune responses is pivotal for tumor immunity as well as for successful anticancer vaccination and therapy. Dead and dying cells produce signals that can influence Ag processing and presentation; however, there is conflicting evidence regarding the immunogenicity of necrotic cell death. We used a mouse model of sterile necrosis, in which mice were injected with sterile primary necrotic cells, to investigate a role of these cells in priming of CD8+ T cells. We discovered a molecular mechanism operating in Ag donor cells that regulates cross-priming of CD8+ T cells during primary sterile necrosis and thereby controls adaptive immune responses. We found that the cellular peptidases dipeptidyl peptidase 3 (DPP-3) and thimet oligopeptidase 1 (TOP-1), both of which are present in nonimmunogenic necrotic cells, eliminated proteasomal degradation products and blocked Ag cross-presentation. While sterile necrotic tumor cells failed to induce CD8+ T cell responses, their nonimmunogenicity could be reversed in vitro and in vivo by inactivation of DPP-3 and TOP-1. These results indicate that control of cross-priming and thereby immunogenicity of primary sterile necrosis relies on proteasome-dependent oligopeptide generation and functional status of peptidases in Ag donor cells.

Neuroprotective Ganglioside Derivatives

DTIC Science & Technology

2006-09-01

SH - SY5Y human neuroblastoma cell line . Derivatives determined to have therapeutic potential are tested in vitro for their...to be cytoprotective in in vitro models using the dopaminergic neurotoxin, 1-methyl-4-phenylpyridinium (MPP+) and the SH - SY5Y cell line . Derivatives...action of these two compounds remains unknown. The ability of GM1 (no preincubation) to protect RA- differentiated SH - SY5Y cells from MPP+

Modelling of OGTT curve identifies 1 h plasma glucose level as a strong predictor of incident type 2 diabetes: results from two prospective cohorts.

PubMed

Alyass, Akram; Almgren, Peter; Akerlund, Mikael; Dushoff, Jonathan; Isomaa, Bo; Nilsson, Peter; Tuomi, Tiinamaija; Lyssenko, Valeriya; Groop, Leif; Meyre, David

2015-01-01

The relevance of the OGTT in predicting type 2 diabetes is unclear. We assessed the performance of 14 OGTT glucose traits in type 2 diabetes prediction. We studied 2,603 and 2,386 Europeans from the Botnia study and Malmö Prevention Project (MPP) cohorts with baseline OGTT data. Over a follow-up period of 4.94 years and 23.5 years, 155 (5.95%) and 467 (19.57%) participants, respectively, developed type 2 diabetes. The main outcome was incident type 2 diabetes. One-hour plasma glucose (1h-PG) was a fair/good predictor of incident type 2 diabetes in the Botnia study and MPP (AUC for receiver operating characteristic [AUCROC] 0.80 [0.77, 0.84] and 0.70 [0.68, 0.73]). 1h-PG alone outperformed the prediction model of multiple clinical risk factors (age, sex, BMI, family history of type 2 diabetes) in the Botnia study and MPP (AUCROC 0.75 [0.72, 0.79] and 0.67 [0.64, 0.70]). The same clinical risk factors added to 1h-PG modestly increased prediction for incident type 2 diabetes (Botnia, AUCROC 0.83 [0.80, 0.86]; MPP, AUCROC 0.74 [0.72, 0.77]). 1h-PG also outperformed HbA1c in predicting type 2 diabetes in the Botnia cohort. A 1h-PG value of 8.9 mmol/l and 8.4 mmol/l was the optimal cut-point for initial screening and selection of high-risk individuals in the Botnia study and MPP, respectively, and represented 30% and 37% of all participants in these cohorts. High-risk individuals had a substantially increased risk of incident type 2 diabetes (OR 8.0 [5.5, 11.6] and 3.8 [3.1, 4.7]) and captured 75% and 62% of all incident type 2 diabetes in the Botnia study and MPP. 1h-PG is a valuable prediction tool for identifying adults at risk for future type 2 diabetes.

Is there a tripeptidyl peptidase in the renal brush-border membrane?

PubMed Central

Kenny, A J; Ingram, J

1988-01-01

A recent claim that the renal brush border contains a tripeptidyl peptidase [Andersen & McDonald (1987) Am. J. Physiol. 253, F649-F655] was examined. In a fluorescent assay, the hydrolysis of Gly-Pro-Met-2-naphthylamide (-NH-Nap) and Gly-Pro-Leu-NH-Nap by pig kidney microvilli was strongly inhibited by amastatin or di-isopropyl phosphorofluoridate (inhibitors of aminopeptidases and dipeptidyl peptidase IV). The products formed were shown to be Gly-Pro and Met-NH-Nap (or Leu-NH-Nap) and free 2-naphthylamine. Specific antibodies to pig and rat aminopeptidase N abolished the apparent tripeptidyl peptidase activity. We conclude that these substrates are hydrolysed by the sequential attack of dipeptidyl peptidase IV and aminopeptidase N and that pig and rat brush borders lack a detectable tripeptidyl peptidase. Images Fig. 1. PMID:3058122

Introduction of Peptidase Genes from Lactobacillus delbrueckii subsp. lactis into Lactococcus lactis and Controlled Expression

PubMed Central

Wegmann, U.; Klein, J. R.; Drumm, I.; Kuipers, O. P.; Henrich, B.

1999-01-01

Peptidases PepI, PepL, PepW, and PepG from Lactobacillus delbrueckii subsp. lactis, which have no counterparts in Lactococcus lactis, and peptidase PepQ were examined to determine their potential to confer new peptidolytic properties to lactococci. Controllable expression of the corresponding genes (pep genes) was achieved by constructing translational fusions with the promoter of the nisA gene (PnisA). A suitable host strain, UKLc10, was constructed by chromosomal integration of the genes encoding the NisRK two-component system into the fivefold peptidase-deficient mutant IM16 of L. lactis. Recombinants of this strain were used to analyze growth, peptidase activities, peptide utilization, and intracellular protein cleavage products. After nisin induction of PnisA::pep fusions, all of the peptidases were visible as distinct bands in protein gels. Despite the fact that identical transcription and translation signals were used to express the pep genes, the relative amounts of individual peptidases varied considerably. All of the peptidases exhibited activities in extracts of recombinant UKLc10 clones, but only PepL and PepG allowed the clones to utilize specific peptide substrates as sources of essential amino acids. In milk medium, induction of pepG and induction of pepW resulted in growth acceleration. The activities of all five peptidases during growth in milk medium were revealed by high-performance liquid chromatography analyses of intracellular amino acid and peptide pools. PMID:10543778

Comparison of the MPP with other supercomputers for LANDSAT data processing

NASA Technical Reports Server (NTRS)

Ozga, Martin

1987-01-01

The massively parallel processor is compared to the CRAY X-MP and the CYBER-205 for LANDSAT data processing. The maximum likelihood classification algorithm is the basis for comparison since this algorithm is simple to implement and vectorizes very well. The algorithm was implemented on all three machines and tested by classifying the same full scene of LANDSAT multispectral scan data. Timings are compared as well as features of the machines and available software.

MicroRNA-7 Promotes Glycolysis to Protect against 1-Methyl-4-phenylpyridinium-induced Cell Death.

PubMed

Chaudhuri, Amrita Datta; Kabaria, Savan; Choi, Doo Chul; Mouradian, M Maral; Junn, Eunsung

2015-05-08

Parkinson disease is associated with decreased activity of the mitochondrial electron transport chain. This defect can be recapitulated in vitro by challenging dopaminergic cells with 1-methyl-4-phenylpyridinium (MPP(+)), a neurotoxin that inhibits complex I of electron transport chain. Consequently, oxidative phosphorylation is blocked, and cells become dependent on glycolysis for ATP production. Therefore, increasing the rate of glycolysis might help cells to produce more ATP to meet their energy demands. In the present study, we show that microRNA-7, a non-coding RNA that protects dopaminergic neuronal cells against MPP(+)-induced cell death, promotes glycolysis in dopaminergic SH-SY5Y and differentiated human neural progenitor ReNcell VM cells, as evidenced by increased ATP production, glucose consumption, and lactic acid production. Through a series of experiments, we demonstrate that targeted repression of RelA by microRNA-7, as well as subsequent increase in the neuronal glucose transporter 3 (Glut3), underlies this glycolysis-promoting effect. Consistently, silencing Glut3 expression diminishes the protective effect of microRNA-7 against MPP(+). Further, microRNA-7 fails to prevent MPP(+)-induced cell death when SH-SY5Y cells are cultured in a low glucose medium, as well as when differentiated ReNcell VM cells or primary mouse neurons are treated with the hexokinase inhibitor, 2-deoxy-d-glucose, indicating that a functional glycolytic pathway is required for this protective effect. In conclusion, microRNA-7, by down-regulating RelA, augments Glut3 expression, promotes glycolysis, and subsequently prevents MPP(+)-induced cell death. This protective effect of microRNA-7 could be exploited to correct the defects in oxidative phosphorylation in Parkinson disease. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Role of peptidases of the intestinal microflora and prey in temperature adaptations of the digestive system in planktivorous and benthivorous fish.

PubMed

Kuz'mina, V V; Skvortsova, E G; Shalygin, M V; Kovalenko, K E

2015-12-01

Many fish enzymatic systems possess limited adaptations to low temperature; however, little data are available to judge whether enzymes of fish prey and intestinal microbiota can mitigate this deficiency. In this study, the activity of serine peptidases (casein-lytic, mainly trypsin and hemoglobin-lytic, mainly chymotrypsin) of intestinal mucosa, chyme and intestinal microflora in four species of planktivorous (blue bream) and benthivorous (roach, crucian carp, perch) was investigated across a wide temperature range (0-70 °C) to identify adaptations to low temperature. At 0 °C, the relative activity of peptidases of intestinal mucosa (<13%) and usually intestinal microflora (5-12.6%) is considerably less than that of chyme peptidases (up to 40% of maximal activity). The level of peptidase relative activity in crucian carp intestinal microflora was 45% of maximal activity. The shape of t°-function curves of chyme peptidase also differs in fish from different biotopes. Fish from the littoral group are characterized by a higher degree of adaptation of chyme casein-lytic peptidases to functioning at low temperatures as compared to fish from the pelagic group. The role of intestinal microbiota and prey peptidases in digestive system adaptations of planktivorous and benthivorous fish to low temperatures is discussed.

Active site of tripeptidyl peptidase II from human erythrocytes is of the subtilisin type.

PubMed Central

Tomkinson, B; Wernstedt, C; Hellman, U; Zetterqvist, O

1987-01-01

The present report presents evidence that the amino acid sequence around the serine of the active site of human tripeptidyl peptidase II is of the subtilisin type. The enzyme from human erythrocytes was covalently labeled at its active site with [3H]diisopropyl fluorophosphate, and the protein was subsequently reduced, alkylated, and digested with trypsin. The labeled tryptic peptides were purified by gel filtration and repeated reversed-phase HPLC, and their amino-terminal sequences were determined. Residue 9 contained the radioactive label and was, therefore, considered to be the active serine residue. The primary structure of the part of the active site (residues 1-10) containing this residue was concluded to be Xaa-Thr-Gln-Leu-Met-Asx-Gly-Thr-Ser-Met. This amino acid sequence is homologous to the sequence surrounding the active serine of the microbial peptidases subtilisin and thermitase. These data demonstrate that human tripeptidyl peptidase II represents a potentially distinct class of human peptidases and raise the question of an evolutionary relationship between the active site of a mammalian peptidase and that of the subtilisin family of serine peptidases. PMID:3313395

Rapid detection of IHNV by molecular padlock recognition and surface-associated isothermal amplification

NASA Astrophysics Data System (ADS)

McCarthy, Erik L.; Egeler, Teressa J.; Bickerstaff, Lee E.; Pereira da Cunha, Mauricio; Millard, Paul J.

2005-11-01

RNA sequences derived from infectious hematopoeitic necrosis virus (IHNV) could be detected using a combination of surface-associated molecular padlock DNA probes (MPP) and rolling circle amplification (RCA) in microcapillary tubes. DNA oligonucleotides with base sequences identical to RNA obtained from IHNV were recognized by MPP. Circularized MPP were then captured on the inner surface of glass microcapillary tubes by immobilized DNA oligonucleotide primers. Extension of the immobilized primers by isothermal RCA gave rise to DNA concatamers, which were in turn bound by the fluorescent reporter SYBR Green II nucleic acid stain, and measured by microfluorimetry. Surface-associated molecular padlock technology, combined with isothermal RCA, exhibited high selectivity and sensitivity without thermal cycling. This technology is applicable to direct RNA and DNA detection, permitting detection of a variety of viral or bacterial pathogens.

Animated computer graphics models of space and earth sciences data generated via the massively parallel processor

NASA Technical Reports Server (NTRS)

Treinish, Lloyd A.; Gough, Michael L.; Wildenhain, W. David

1987-01-01

The capability was developed of rapidly producing visual representations of large, complex, multi-dimensional space and earth sciences data sets via the implementation of computer graphics modeling techniques on the Massively Parallel Processor (MPP) by employing techniques recently developed for typically non-scientific applications. Such capabilities can provide a new and valuable tool for the understanding of complex scientific data, and a new application of parallel computing via the MPP. A prototype system with such capabilities was developed and integrated into the National Space Science Data Center's (NSSDC) Pilot Climate Data System (PCDS) data-independent environment for computer graphics data display to provide easy access to users. While developing these capabilities, several problems had to be solved independently of the actual use of the MPP, all of which are outlined.

The factorization of large composite numbers on the MPP

NASA Technical Reports Server (NTRS)

Mckurdy, Kathy J.; Wunderlich, Marvin C.

1987-01-01

The continued fraction method for factoring large integers (CFRAC) was an ideal algorithm to be implemented on a massively parallel computer such as the Massively Parallel Processor (MPP). After much effort, the first 60 digit number was factored on the MPP using about 6 1/2 hours of array time. Although this result added about 10 digits to the size number that could be factored using CFRAC on a serial machine, it was already badly beaten by the implementation of Davis and Holdridge on the CRAY-1 using the quadratic sieve, an algorithm which is clearly superior to CFRAC for large numbers. An algorithm is illustrated which is ideally suited to the single instruction multiple data (SIMD) massively parallel architecture and some of the modifications which were needed in order to make the parallel implementation effective and efficient are described.

A digestive prolyl carboxypeptidase in Tenebrio molitor larvae.

PubMed

Goptar, Irina A; Shagin, Dmitry A; Shagina, Irina A; Mudrik, Elena S; Smirnova, Yulia A; Zhuzhikov, Dmitry P; Belozersky, Mikhail A; Dunaevsky, Yakov E; Oppert, Brenda; Filippova, Irina Yu; Elpidina, Elena N

2013-06-01

Prolyl carboxypeptidase (PRCP) is a lysosomal proline specific serine peptidase that also plays a vital role in the regulation of physiological processes in mammals. In this report, we isolate and characterize the first PRCP in an insect. PRCP was purified from the anterior midgut of larvae of a stored product pest, Tenebrio molitor, using a three-step chromatography strategy, and it was determined that the purified enzyme was a dimer. The cDNA of PRCP was cloned and sequenced, and the predicted protein was identical to the proteomic sequences of the purified enzyme. The substrate specificity and kinetic parameters of the enzyme were determined. The T. molitor PRCP participates in the hydrolysis of the insect's major dietary proteins, gliadins, and is the first PRCP to be ascribed a digestive function. Our collective data suggest that the evolutionary enrichment of the digestive peptidase complex in insects with an area of acidic to neutral pH in the midgut is a result of the incorporation of lysosomal peptidases, including PRCP. Published by Elsevier Ltd.

Biochemical properties and evaluation of washing performance in commercial detergent compatibility of two collagenolytic serine peptidases secreted by Aspergillus fischeri and Penicillium citrinum.

PubMed

Ida, Érika Lika; da Silva, Ronivaldo Rodrigues; de Oliveira, Tássio Brito; Souto, Tatiane Beltramini; Leite, Juliana Abigail; Rodrigues, André; Cabral, Hamilton

2017-03-16

Filamentous fungi secrete diverse peptidases with different biochemical properties, which is of considerable importance for application in various commercial sectors. In this study, we describe the isolation of two fungal species collected from the soil of decayed organic matter: Aspergillus fischeri and Penicillium citrinum. In a submerged bioprocess, we observed better peptidase production with the fungus P. citrinum, which reached a peak production at 168 h with 760 U/mL, in comparison with the fungus A. fischeri, which reached a peak production at 72 h with 460 U/mL. In both situations, the fermentative medium contained 0.5% crushed feathers as a source of nitrogen. On performing biochemical characterization, we detected two alkaline serine peptidases: The one secreted by P. citrinum had optimal activity at pH 7.0 and at 45°C, while the one secreted by A. fischeri had optimal activity in pH 6.5-8 and at 55-60°C. Metallic ions were effective in modulating these peptidases; in particular, Cu 2+ promoted negative modulation of both peptidases. The peptidases were stable and functional under conditions of nonionic surfactants, temperatures up to 45°C for 1 h, and incubation over a wide pH range. In addition, it was observed that both peptidases had the capacity to hydrolyze collagen and performed well in removing an egg protein stain when supplemented into a commercial powder detergent; this was especially true for the peptidase from P. citrinum.

Metabolism of neuropeptides. Hydrolysis of the angiotensins, bradykinin, substance P and oxytocin by pig kidney microvillar membranes.

PubMed Central

Stephenson, S L; Kenny, A J

1987-01-01

Microvillar membranes derived from the brush border of the renal proximal tubule are very rich in peptidases. Pig kidney microvilli contain endopeptidase-24.11 associated with a battery of exopeptidases. The manner by which some neuropeptides are degraded by the combined attack of the peptidases of this membrane has been investigated. The contribution of individual peptidases was assessed by including inhibitors (phosphoramidon, captopril, amastatin and di-isopropyl fluorophosphate) with the membrane fraction when incubated with the peptides. Substance P, bradykinin and angiotensins I, II and III and insulin B-chain were rapidly hydrolysed by kidney microvilli. Oxytocin was hydrolysed much more slowly, but no products were detected from [Arg8]vasopressin or insulin under the conditions used for other peptides. The peptide bonds hydrolysed were identified and the contributions of the different peptidases were quantified. For each of the susceptible peptides, the main contribution came from endopeptidase-24.11 (inhibited by phosphoramidon). Peptidyl dipeptidase A (angiotensin-I-converting enzyme) was of less importance, even in respect of angiotensin I and bradykinin. When [2,3-Pro3,4-3H]bradykinin was also investigated at a lower concentration (20 nM), the conclusions in regard to the contributions of the two peptidases were unchanged. The possibility that endopeptidase-24.11 might attack within the six-residue disulphide-bridged rings of oxytocin and vasopressin was examined by dansyl(5-dimethylaminonaphthalene-1-sulphonyl)ation and by reduction and carboxymethylation of the products after incubation. Additional peptides were only observed after prolonged incubation, consistent with hydrolysis at the Tyr2-Ile3 and Tyr2-Phe3 bonds respectively. These results show that a range of neuropeptides are efficiently degraded by microvillar membranes and that endopeptidase-24.11 plays a key role in this process. PMID:2436610

Peptidases in dog-ileum circular and longitudinal smooth-muscle plasma membranes. Their relative contribution to the metabolism of neurotensin.

PubMed

Checler, F; Ahmad, S; Kostka, P; Barelli, H; Kitabgi, P; Fox, J A; Kwan, C Y; Daniel, E E; Vincent, J P

1987-07-15

We established the content in neuropeptide-metabolizing peptidases present in highly purified plasma membranes prepared from the circular and longitudinal muscles of dog ileum. Activities were measured by the use of fluorigenic substrates and the identities of enzymes were confirmed by the use of specific peptidase inhibitors. Endopeptidase 24.11, angiotensin-converting enzyme, post-proline dipeptidyl aminopeptidase and aminopeptidases were found in both membrane preparations. Proline endopeptidase was only detected in circular smooth muscle plasma membranes while pyroglutamyl-peptide hydrolase was not observed in either tissue. The relative contribution of these peptidases to the inactivation of neurotensin was assessed. The enzymes involved in the primary inactivating cleavages occurring on the neurotensin molecule were as follows. In both membrane preparations, endopeptidase 24.11 was responsible for the formation of neurotensin-(1-11) and contributed to the formation of neurotensin-(1-10); a recently purified neurotensin-degrading neutral metallopeptidase was also involved in the formation of neurotensin-(1-10). A carboxypeptidase-like activity hydrolysed neurotensin at the Ile12-Leu13 peptide bond, leading to the formation of neurotensin-(1-12). Proline endopeptidase and endopeptidase 24.15 only occurred in circular muscle plasma membranes, yielding neurotensin-(1-7) and neurotensin-(1-8), respectively. In addition, the secondary processing of neurotensin degradation products was catalyzed by the following peptidases. In circular and longitudinal muscle membranes, angiotensin-converting enzyme converted neurotensin-(1-10) into neurotensin-(1-8) and tyrosine resulted from the rapid hydrolysis of neurotensin-(11-13) by bestatin-sensitive aminopeptidases. A post-proline dipeptidyl aminopeptidase activity converted neurotensin-(9-13) into neurotensin-(11-13) in circular muscle plasma membranes. The mechanism of neurotensin inactivation occurring in these membranes will be compared to that previously established for membranes from central origin.

Beneficial Effects of HIV Peptidase Inhibitors on Fonsecaea pedrosoi: Promising Compounds to Arrest Key Fungal Biological Processes and Virulence

PubMed Central

Palmeira, Vanila F.; Kneipp, Lucimar F.; Rozental, Sonia; Alviano, Celuta S.; Santos, André L. S.

2008-01-01

Background Fonsecaea pedrosoi is the principal etiologic agent of chromoblastomycosis, a fungal disease whose pathogenic events are poorly understood. Current therapy for chromoblastomycosis is suboptimal due to toxicity of the available therapeutic agents and the emergence of drug resistance. Compounding these problems is the fact that endemic countries and regions are economically poor. Purpose and Principal Findings In the present work, we have investigated the effect of human immunodeficiency virus (HIV) peptidase inhibitors (PIs) on the F. pedrosoi conidial secreted peptidase, growth, ultrastructure and interaction with different mammalian cells. All the PIs impaired the acidic conidial-derived peptidase activity in a dose-dependent fashion, in which nelfinavir produced the best inhibitory effect. F. pedrosoi growth was also significantly reduced upon exposure to PIs, especially nelfinavir and saquinavir. PIs treatment caused profound changes in the conidial ultrastructure as shown by transmission electron microscopy, including invaginations in the cytoplasmic membrane, disorder and detachment of the cell wall, enlargement of fungi cytoplasmic vacuoles, and abnormal cell division. The synergistic action on growth ability between nelfinavir and amphotericin B, when both were used at sub-inhibitory concentrations, was also observed. PIs reduced the adhesion and endocytic indexes during the interaction between conidia and epithelial cells (CHO), fibroblasts or macrophages, in a cell type-dependent manner. Moreover, PIs interfered with the conidia into mycelia transformation when in contact with CHO and with the susceptibility killing by macrophage cells. Conclusions/Significance Overall, by providing the first evidence that HIV PIs directly affects F. pedrosoi development and virulence, these data add new insights on the wide-spectrum efficacy of HIV PIs, further arguing for the potential chemotherapeutic targets for aspartyl-type peptidase produced by this human pathogen. PMID:18852883

Identification of peptidase substrates in human plasma by FTMS based differential mass spectrometry

NASA Astrophysics Data System (ADS)

Yates, Nathan A.; Deyanova, Ekaterina G.; Geissler, Wayne; Wiener, Matthew C.; Sachs, Jeffrey R.; Wong, Kenny K.; Thornberry, Nancy A.; Sinha Roy, Ranabir; Settlage, Robert E.; Hendrickson, Ronald C.

2007-01-01

Approximately 2% of the human genome encodes for proteases. Unfortunately, however, the biological roles of most of these enzymes remain poorly defined, since the physiological substrates are typically unknown and are difficult to identify using traditional methods. We have developed a proteomics experiment based on FTMS profiling and differential mass spectrometry (dMS) to identify candidate endogenous substrates of proteases using fractionated human plasma as the candidate substrate pool. Here we report proof-of-concept experiments for identifying in vitro substrates of aminopeptidase P2, (APP2) and dipeptidyl peptidase 4 (DPP-4), a peptidase of therapeutic interest for the treatment of type 2 diabetes. For both proteases, previously validated peptide substrates spiked into the human plasma pool were identified. Of note, the differential mass spectrometry experiments also identified novel substrates for each peptidase in the subfraction of human plasma. Targeted MS/MS analysis of these peptides in the complex human plasma pool and manual confirmation of the amino acid sequences led to the identification of these substrates. The novel DPP-4 substrate EPLGRQLTSGP was chemically synthesized and cleavage kinetics were determined in an in vitro DPP-4 enzyme assay. The apparent second order rate constant (kcat/KM) for DPP-4-mediated cleavage was determined to be 2.3 x 105 M-1 s-1 confirming that this peptide is efficiently processed by the peptidase in vitro. Collectively, these results demonstrate that differential mass spectrometry has the potential to identify candidate endogenous substrates of target proteases from a human plasma pool. Importantly, knowledge of the endogenous substrates can provide useful insight into the biology of these enzymes and provides useful biomarkers for monitoring their activity in vivo.

Astacin Family Metallopeptidases and Serine Peptidase Inhibitors in Spider Digestive Fluid

PubMed Central

Foradori, Matthew J.; Tillinghast, Edward K.; Smith, J. Stephen; Townley, Mark A.; Mooney, Robert E.

2006-01-01

Digestive fluid of the araneid spider Argiope aurantia is known to contain zinc metallopeptidases. Using anion-exchange chromatography, size-exclusion chromatography, sucrose density gradient centrifugation, and gel electrophoresis, we isolated two lower-molecular-mass peptidases, designated p16 and p18. The N-terminal amino acid sequences of p16 (37 residues) and p18 (20 residues) are 85% identical over the first 20 residues and are most similar to the N-terminal sequences of the fully active form of meprin (β subunits) from several vertebrates (47–52% and 50–60% identical, respectively). Meprin is a peptidase in the astacin (M12A) subfamily of the astacin (M12) family. Additionally, a 66-residue internal sequence obtained from p16 aligns with the conserved astacin subfamily domain. Thus, at least some spider digestive peptidases appear related to astacin of decapod crustaceans. However, important differences between spider and crustacean metallopeptidases with regard to isoelectric point and their susceptibility to hemolymph-borne inhibitors are demonstrated. Anomalous behavior of the lower-molecular-mass Argiope peptidases during certain fractionation procedures indicates that these peptidases may take part in reversible associations with each other or with other proteins. A. aurantia digestive fluid also contains inhibitory activity effective against insect digestive peptidases. Here we present evidence for at least thirteen, heat-stable serine peptidase inhibitors ranging in molecular mass from about 15 to 32 kDa. PMID:16458560

Active site of tripeptidyl peptidase II from human erythrocytes is of the subtilisin type

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomkinson, B.; Wernstedt, C.; Hellman, U.

1987-11-01

The present report presents evidence that the amino acid sequence around the serine of the active site of human tripeptidyl peptidase II is of the subtilisin type. The enzyme from human erythrocytes was covalently labeled at its active site with (/sup 3/H)diisopropyl fluorophosphate, and the protein was subsequently reduced, alkylated, and digested with trypsin. The labeled tryptic peptides were purified by gel filtration and repeated reversed-phase HPLC, and their amino-terminal sequences were determined. Residue 9 contained the radioactive label and was, therefore, considered to be the active serine residue. The primary structure of the part of the active site (residuesmore » 1-10) containing this residue was concluded to be Xaa-Thr-Gln-Leu-Met-Asx-Gly-Thr-Ser-Met. This amino acid sequence is homologous to the sequence surrounding the active serine of the microbial peptidases subtilisin and thermitase. These data demonstrate that human tripeptidyl peptidase II represents a potentially distinct class of human peptidases and raise the question of an evolutionary relationship between the active site of a mammalian peptidase and that of the subtilisin family of serine peptidases.« less

Parallel image compression

NASA Technical Reports Server (NTRS)

Reif, John H.

1987-01-01

A parallel compression algorithm for the 16,384 processor MPP machine was developed. The serial version of the algorithm can be viewed as a combination of on-line dynamic lossless test compression techniques (which employ simple learning strategies) and vector quantization. These concepts are described. How these concepts are combined to form a new strategy for performing dynamic on-line lossy compression is discussed. Finally, the implementation of this algorithm in a massively parallel fashion on the MPP is discussed.

Transforming the Department of State: Adapting Operational Capacities and Capabilities to the Post-9/11 Reality, Evolving Interagency Responsibilities, and the Challenges of the 21st Century

DTIC Science & Technology

2006-04-14

combination of the Strategic Plan, MPPs, and BPPs goals, along with performance, and accountability plans. Three other documents are inherently important...DOS Strategic Plan, Mission Performance Plan (MPP), Bureau Performance Plan ( BPP ). NSC representation, POLADs, Embassy Country Teams, and...the world. DOS Strategic Plan, Mission Performance Plan (MPP), Bureau Performance Plan ( BPP ). NSC representation, POLADs, Exchange

Reciprocal Interactions between Multiple Myeloma Cells and Osteoprogenitor Cells Affect Bone Formation and Tumor Growth

DTIC Science & Technology

2015-12-01

cells (HSCs) are multipotent cells that differentiate into myeloid, lymphoid and erythroid lineages, and have short-term or long-term regenerative...All rights reserved Nature Reviews | Rheumatology a b MPP CMP CLP Lymphoid cells NK cellB cell T cell Megakaryocyte and erythrocytes Macrophage and...into other cell types. CLP, common lymphoid progenitor; CMP, common myeloid progenitor; MPP, multipotent progenitor; NK cell , natural killer cell . R E

Variable toxicological response to the loss of OXPHOS through 1-methyl-4-phenylpyridinium-induced mitochondrial damage and anoxia in diverse neural immortal cell lines.

PubMed

Mazzio, Elizabeth A; Soliman, Youssef I; Soliman, Karam F A

2010-12-01

Immortal cell lines are used to investigate various aspects of neurodegeneration. These cells display high glycolytic turnover rate and produce an abundant amounts of lactate. Our previous studies indicate that these cells survive the loss of mitochondrial oxidative phosphorylation (OXPHOS) with ample glucose supply. In the current study, we investigate if cell type (w/variation in basal metabolic rate (MR)), can alter glucose utilization patterns which in turn may affect LC(50) for the mitochondrial toxin 1-methyl-4-phenylpyridinium (MPP(+)) in various cell lines. The data obtained indicate that cell lines MRs examined were generally consistent with the average of species adult body weight where mouse N-2A > rat-PC-12 > human SH-SY5Y. A higher MR was associated with accelerated utilization of glucose and earlier cell death with MPP(+): LC(50) mouse = 294 µM, rat = 695 µM, and human = 5.25 mM at 24 h. Cell death appears to be a function of the velocity by which glucose disappears, leading to the failure of glycolysis and subsequent halt of energy production. Similar effects were also observed at higher plating densities where the demand for glucose is amplified. A time-lapse study of MPP(+) toxicity (0-36 h) in N-2A cells indicates that an anaerobic shift occurs as early as 2 h (evidenced by a rise in lactate), followed by a descent in glucose concentrations at 4 h and exhaustion of glucose supplies at 22 h which was associated with the first detectable sign of cell death. It was also noted that MPP(+) toxicity was not associated with the generation of reactive oxygen species (O (2) (-) , H(2)0(2), and NO(2)) and was not attenuated by adding catalase or superoxide dismutase to the media. On the other hand, MPP(+) toxicity was reversed by providing additional supply of glucose, pyruvate ± mitochondrial monocarboxylate transporter blocker (α-cyano-4-HCA), or pyruvate ± pyruvate dehydrogenase inhibitor (octanoyl-CoA), suggesting that the exclusive anaerobic survival compensates for the loss of OXPHOS by MPP(+). To examine if neuroblastoma were capable of surviving the deprivation of O(2) for 24 h, a range of hypoxia to anoxia was established with various concentrations of dithionite. The data suggest that cell lines examined continue to thrive when incubated with high-glucose media (25 mM). In summary, vulnerability of immortal neuroblastoma cell lines to MPP(+) toxicity is dependent upon glucose concentrations within the media and cell MR, which indirectly dominates the velocity of glucose use and its end point disappearance, leading to cell death by ergogenic failure.

HvPap-1 C1A Protease and HvCPI-2 Cystatin Contribute to Barley Grain Filling and Germination1

PubMed Central

Velasco-Arroyo, Blanca; Cambra, Ines; Gonzalez-Melendi, Pablo; Lopez-Gonzalvez, Angeles; Garcia, Antonia

2016-01-01

Proteolysis is an essential process throughout the mobilization of storage proteins in barley (Hordeum vulgare) grains during germination. It involves numerous types of enzymes, with C1A Cys proteases the most abundant key players. Manipulation of the proteolytic machinery is a potential way to enhance grain yield and quality, and it could influence the mobilization of storage compounds along germination. Transgenic barley plants silencing or over-expressing the cathepsin F-like HvPap-1 Cys protease show differential accumulation of storage molecules such as starch, proteins, and free amino acids in the grain. It is particularly striking that the HvPap-1 artificial microRNA lines phenotype show a drastic delay in the grain germination process. Alterations to the proteolytic activities in the over-expressing and knock-down grains associated with changes in the level of expression of several C1A peptidases were also detected. Similarly, down-regulating cystatin Icy-2, one of the proteinaceous inhibitors of the cathepsin F-like protease, also has important effects on grain filling. However, the ultimate physiological influence of manipulating a peptidase or an inhibitor cannot be always predicted, since the plant tries to compensate the modified proteolytic effects by modulating the expression of some other peptidases or their inhibitors. PMID:26912343

Digestive peptidase evolution in holometabolous insects led to a divergent group of enzymes in Lepidoptera.

PubMed

Dias, Renata O; Via, Allegra; Brandão, Marcelo M; Tramontano, Anna; Silva-Filho, Marcio C

2015-03-01

Trypsins and chymotrypsins are well-studied serine peptidases that cleave peptide bonds at the carboxyl side of basic and hydrophobic L-amino acids, respectively. These enzymes are largely responsible for the digestion of proteins. Three primary processes regulate the activity of these peptidases: secretion, precursor (zymogen) activation and substrate-binding site recognition. Here, we present a detailed phylogenetic analysis of trypsins and chymotrypsins in three orders of holometabolous insects and reveal divergent characteristics of Lepidoptera enzymes in comparison with those of Coleoptera and Diptera. In particular, trypsin subsite S1 was more hydrophilic in Lepidoptera than in Coleoptera and Diptera, whereas subsites S2-S4 were more hydrophobic, suggesting different substrate preferences. Furthermore, Lepidoptera displayed a lineage-specific trypsin group belonging only to the Noctuidae family. Evidence for facilitated trypsin auto-activation events were also observed in all the insect orders studied, with the characteristic zymogen activation motif complementary to the trypsin active site. In contrast, insect chymotrypsins did not seem to have a peculiar evolutionary history with respect to their mammal counterparts. Overall, our findings suggest that the need for fast digestion allowed holometabolous insects to evolve divergent groups of peptidases with high auto-activation rates, and highlight that the evolution of trypsins led to a most diverse group of enzymes in Lepidoptera. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of food processing and simulated gastrointestinal digestion on gliadin immunoreactivity in rolls.

PubMed

Brzozowski, Bartosz

2018-07-01

The enzymatic modification of wheat proteins during dough fermentation and its digestion as supported by peptidases of microbiological origin can result in the degradation of important peptides in the pathogenesis of coeliac disease. However, baking bread and the high temperature associated with this could change the physicochemical and immunological properties of proteins. Thermal changes in the spatial structure of proteins and their hydrolysis can lead to a masking or degrading of immunoreactive peptides. The addition of prolyl endopeptidase (PEP), comprising peptidases isolated from Lactobacillus acidophilus 5e2 (LA) or transglutaminase (TG) in the course of fermentation, decreases its immunoreactivity by 83.9%, 51.9% and 18.5%, respectively. An analysis of the fractional composition of gliadins revealed that γ- and ω-gliadins are the proteins most susceptible to enzymatic modification. Hydrolysis of wheat storage proteins with PEP and LA reduces the content of αβ-, γ- and ω-gliadins by 13.7%, 60.2% and 41.9% for PEP and by 22.1%, 43.5% and 36.9% for LA, respectively. Cross-linking of proteins with TG or their hydrolysis by PEP and LA peptidases during the process of forming wheat dough, followed by digesting bread samples with PEP and LA peptidases, decreases the immunoreactivity of bread hydrolysates from 2.4% to 0.02%. The content of peptide detected in polypeptide sequences is 263.4 ± 3.3, 30.9 ± 1.5 and 7.9 ± 0.4 mg kg -1 in samples of hydrolysates of bread digested with PEP, as produced from dough modified by TG, PEP and LA, respectively. Enzymatic pre-modification of proteins during the process of dough fermentation decreases their immunoreactive potential, such that fewer peptides recognised by R5 antibodies are released during the digestion process from the bread matrix. Immunoreactive peptides are degraded more effectively when digestive enzymes are supported by the addition of PEP. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Endothelin-1 inactivating peptidase in the human kidney and urine.

PubMed

Janas, J; Sitkiewicz, D; Januszewicz, A; Szczesniak, C; Grenda, R; Janas, R M

2000-04-01

Recently, an apparently novel, specific endothelin-1 inactivating metalloendopeptidase (ET-1 peptidase) has been isolated from the rat kidney. In this study we attempted to determine whether the same or a similar peptidase is present in the human kidney, and whether the enzyme is excreted into the urine. The urinary ET-1 peptidase could serve as an indirect index of the renal endothelin system, both in physiology and pathophysiology. Kidney specimens were obtained from part of nephrectomized kidneys unaffected by any neoplastic process from six adult patients. The enzyme was purified using differential centrifugation, detergent solubilization of the membrane proteins, ultrafiltration and nondenaturing gel electrophoresis. The enzyme activity assays were performed at pH 5.5 and 37 degrees C in the presence of increasing concentrations of unlabelled peptides and inhibitors using a fixed amount of [125I]ET-1 as substrate. The degradation extent was quantified with trichloroacetic acid precipitation and high performance liquid chromatography. The degrading activity of ET-1 was determined in urine samples from adult patients with hypertension, children with chronic renal failure and those with stable renal allograft ET-1 peptidase from the human kidney displays characteristics close to that of the rat ET-1 peptidase we have recently described (J. Hypertens 1994; 12:1155-1162). The enzyme, a membrane-bound metalloendopeptidase, exhibits low electro- phoretical mobility on nondenaturing gel (Rf 0.08); it is an apparently heterologous structure comprising three enzymatically inactive subunits, it has a pH optimum at 5.5, a nanomolar range affinity to the ET-1 (KM 180 nmol/l) that is hydrolysed to two main degradation products, and a 10-100-fold lower affinity to big ET-1 (KM 11.5 micromol/l), endothelin 11 21 fragment (KM 15.3 micromol/l), endothelin antagonist Trp-Leu-Asp-Ile-Ile-Trp (KM 3.1 micromol/I), gastrin (KM 2.2 micromol/l) and cholecystokinin (KM 4.0 micromol/l). Substance P, neuropeptide Y, atrial natriuretic peptide, bradykinin, angiotensin II and enkephalin were poor substrates for the enzyme. The most powerful inhibitors of the ET-1 peptidase included thiorphan (IC50 0.28 nmol/l), phosphoramidon (IC50 0.55 nmol/l), phenanthroline (IC50 11.5 micromol/l), cyclosporin (IC50 400 micromol/l), phosphate (IC50 1.2 mmol/l), citrate (IC50 0.6 mmol/l) and aniline naphthalene sulphonic acid (IC50 0.25 mmol/l). Our data suggest that three ET-1 degrading peptidases with optimal activity at pH 4.5, 5.5 and 7.0, respectively, are excreted into the urine. The enzyme with a pH optimum 4.5 is of lysosomal origin whereas the two other enzymes correspond by their pH optima to the renal ET-1 peptidase and neutral endopeptidase. We have found statistically significant increases (P < 0.001) in the activity of both lysosomal and ET-1 peptidase in the urine in patients with hypertension and in children with chronic renal failure compared with healthy subjects or children with stable renal allograft Human kidney contains an acidic, highly specific endothelin-1 inactivating metalloendopeptidase that may have a key role in the regulation of concentrations of renal and circulating endothelins. The enzyme is excreted into the urine where its activity seems to be increased in patients with hypertension and chronic renal failure; it may potentially serve as an indirect index of the renal endothelin system.

S46 Peptidases are the First Exopeptidases to be Members of Clan PA

PubMed Central

Sakamoto, Yasumitsu; Suzuki, Yoshiyuki; Iizuka, Ippei; Tateoka, Chika; Roppongi, Saori; Fujimoto, Mayu; Inaka, Koji; Tanaka, Hiroaki; Masaki, Mika; Ohta, Kazunori; Okada, Hirofumi; Nonaka, Takamasa; Morikawa, Yasushi; Nakamura, Kazuo T.; Ogasawara, Wataru; Tanaka, Nobutada

2014-01-01

The dipeptidyl aminopeptidase BII (DAP BII) belongs to a serine peptidase family, S46. The amino acid sequence of the catalytic unit of DAP BII exhibits significant similarity to those of clan PA endopeptidases, such as chymotrypsin. However, the molecular mechanism of the exopeptidase activity of family S46 peptidase is unknown. Here, we report crystal structures of DAP BII. DAP BII contains a peptidase domain including a typical double β-barrel fold and previously unreported α-helical domain. The structures of peptide complexes revealed that the α-helical domain covers the active-site cleft and the side chain of Asn330 in the domain forms hydrogen bonds with the N-terminus of the bound peptide. These observations indicate that the α-helical domain regulates the exopeptidase activity of DAP BII. Because S46 peptidases are not found in mammals, we expect that our study will be useful for the design of specific inhibitors of S46 peptidases from pathogens. PMID:24827749

Joint Analysis of Strain and Parent-of-Origin Effects for Recombinant Inbred Intercrosses Generated from Multiparent Populations with the Collaborative Cross as an Example.

PubMed

Liu, Yanyan; Xiong, Sican; Sun, Wei; Zou, Fei

2018-02-02

Multiparent populations (MPP) have become popular resources for complex trait mapping because of their wider allelic diversity and larger population size compared with traditional two-way recombinant inbred (RI) strains. In mice, the collaborative cross (CC) is one of the most popular MPP and is derived from eight genetically diverse inbred founder strains. The strategy of generating RI intercrosses (RIX) from MPP in general and from the CC in particular can produce a large number of completely reproducible heterozygote genomes that better represent the (outbred) human population. Since both maternal and paternal haplotypes of each RIX are readily available, RIX is a powerful resource for studying both standing genetic and epigenetic variations of complex traits, in particular, the parent-of-origin (PoO) effects, which are important contributors to many complex traits. Furthermore, most complex traits are affected by >1 genes, where multiple quantitative trait locus mapping could be more advantageous. In this paper, for MPP-RIX data but taking CC-RIX as a working example, we propose a general Bayesian variable selection procedure to simultaneously search for multiple genes with founder allelic effects and PoO effects. The proposed model respects the complex relationship among RIX samples, and the performance of the proposed method is examined by extensive simulations. Copyright © 2018 Liu et al.

[Evaluation of phosphate-containing amendments on remediation effect and influential factors in a lead/zinc mining tailings contaminated soil using TCLP and forms].

PubMed

Chen, Jian-Jun; Yu, Tian-Ming; Wang, Bi-Ling; Xie, Zheng-Miao

2010-01-01

A pot experiment was conducted to evaluate the effects of phosphate-containing (P) amendments on the toxicity and bioavailability of Pb and Zn in a soil contaminated by mining tailings using toxicity characteristic leaching procedure (TCLP) and water soluble, exchangeable leaching procedures in order to find out the appropriate P application rates to reduce the soil TCLP extractable Pb to below the USA EPA's regulatory limit levels. The results showed that TCLP extractable Pb concentrations were significantly decreased by up to 93.3% for MPP treatments and up to 68.5% for SSP treatments after P application. The dose required to reduce leachable Pb below the EPA's regulatory limit level was found to be around the molar ratio of v(P/Pb) = 0.6 for MPP and 1.8 for SSP. It was also found both MPP and SSP could reduce the exchangeable Pb and Zn concentrations that all bio-available Zn forms including water soluble, exchangeable, and TCLP extractable forms in soil were significantly and negatively correlated to soil pH values, indicating that the content of Zn in the soil was mostly controlled by soil pH value even after P application. These results suggest that P as MPP and SSP could successfully decrease the toxicity and bioavailability of Pb and Zn in the contaminated soil.

Differentiating pheochromocytoma from lipid-poor adrenocortical adenoma by CT texture analysis: feasibility study.

PubMed

Zhang, Gu-Mu-Yang; Shi, Bing; Sun, Hao; Jin, Zheng-Yu; Xue, Hua-Dan

2017-09-01

To investigate the feasibility of using CT texture analysis (CTTA) to differentiate pheochromocytoma from lipid-poor adrenocortical adenoma (lp-ACA). Ninety-eight pheochromocytomas and 66 lp-ACAs were included in this retrospective study. CTTA was performed on unenhanced and enhanced images. Receiver operating characteristic (ROC) analysis was performed, and the area under the ROC curve (AUC) was calculated for texture parameters that were significantly different for the objective. Diagnostic accuracies were evaluated using the cutoff values of texture parameters with the highest AUCs. Compared to lp-ACAs, pheochromocytomas had significantly higher mean gray-level intensity (Mean), entropy, and mean of positive pixels (MPP), but lower skewness and kurtosis on unenhanced images (P < 0.001). On enhanced images, these texture-quantifiers followed a similar trend where Mean, entropy, and MPP were higher, but skewness and kurtosis were lower in pheochromocytomas. Standard deviation (SD) was also significantly higher in pheochromocytomas on enhanced images. Mean and MPP quantified from no filtration on unenhanced CT images yielded the highest AUC of 0.86 ± 0.03 (95% CI 0.81-0.91) at a cutoff value of 34.0 for Mean and MPP, respectively (sensitivity = 79.6%, specificity = 83.3%, accuracy = 81.1%). It was feasible to use CTTA to differentiate pheochromocytoma from lp-ACA.

The concordance between upper and lower respiratory microbiota in children with Mycoplasma pneumoniae pneumonia.

PubMed

Dai, Wenkui; Wang, Heping; Zhou, Qian; Feng, Xin; Lu, Zhiwei; Li, Dongfang; Yang, Zhenyu; Liu, Yanhong; Li, Yinhu; Xie, Gan; Shen, Kunling; Yang, Yonghong; Zheng, Yuejie; Li, Shuaicheng

2018-05-23

In recent years, the morbidity of Mycoplasma pneumoniae pneumonia (MPP) has dramatically increased in China. An increasing number of studies indicate that an imbalance in the respiratory microbiota is associated with respiratory infection. We selected 28 hospitalized patients infected with M. pneumoniae and 32 healthy children. Nasopharyngeal (NP) and oropharyngeal (OP) swabs were collected from healthy children, whereas NP, OP and bronchoalveolar lavage (BAL) specimens were collected from patients. Microbiota analysis was performed on all microbial samples using 16 S ribosomal RNA (16 S rRNA) sequencing. The NP microbial samples in healthy children were divided into two groups, which were dominated by either Staphylococcus or mixed microbial components. The respiratory microbiota in pneumonia patients harbored a lower microbial diversity compared to healthy children, and both the NP and OP microbiota of patients differed significantly from that of healthy children. Hospitalized MPP children with a higher abundance of Mycoplasma in the BAL fluid (BALF) microbiota tended to suffer longer hospitalization lengths and higher peak fevers and serum C-reactive protein levels. Concordance analysis explained the succession of imbalanced NP microbiota to the OP and lung in diseased children. However, the association of the abundance of Mycoplasma in BALF microbiota with that in NP or OP microbiota varied among individuals, which suggested the sensitivity of BALF in MPP diagnostics, mirroring MPP severity.

Jump Squat is More Related to Sprinting and Jumping Abilities than Olympic Push Press.

PubMed

Loturco, I; Kobal, R; Maldonado, T; Piazzi, A F; Bottino, A; Kitamura, K; Abad, C C C; Pereira, L A; Nakamura, F Y

2017-07-01

The aim of this study was to test the relationships between jump squat (JS) and Olympic push press (OPP) power outputs and performance in sprint, squat jump (SJ), countermovement jump (CMJ) and change of direction (COD) speed tests in elite soccer players. 27 athletes performed a maximum power load test to determine their bar mean propulsive power (MPP) and bar mean propulsive velocity (MPV) in the JS and OPP exercises. Magnitude-based inference was used to compare the exercises. The MPV was almost certainly higher in the OPP than in the JS. The MPP relative to body mass (MPP REL) was possibly higher in the OPP. Only the JS MPP REL presented very large correlations with linear speed ( r> 0.7, for speed in 5, 10, 20 and 30 m) and vertical jumping abilities ( r> 0.8, for SJ and CMJ), and moderate correlation with COD speed ( r= 0.45). Although significant (except for COD), the associations between OPP outcomes and field-based measurements (speed, SJ and CMJ) were all moderate, ranging from 0.40 to 0.48. In a group composed of elite soccer players, the JS exercise is more associated with jumping and sprinting abilities than the OPP. Longitudinal studies are needed to confirm if these strong relationships imply superior training effects in favor of the JS exercise. © Georg Thieme Verlag KG Stuttgart · New York.

Environmental friendly crush-magnetic separation technology for recycling metal-plated plastics from end-of-life vehicles.

PubMed

Xue, Mianqiang; Li, Jia; Xu, Zhenming

2012-03-06

Metal-plated plastics (MPP), which are important from the standpoint of aesthetics or even performance, are increasingly employed in a wide variety of situations in the automotive industry. Serious environmental problems will be caused if they are not treated appropriately. Therefore, recycling of MPP is an important subject not only for resource recycling but also for environmental protection. This work represents a novel attempt to deal with the MPP. A self-designed hammer crusher was used to liberate coatings from the plastic substrate. The size distribution of particles was analyzed and described by the Rosin-Rammler function model. The optimum retaining time of materials in the crusher is 3 min. By this time, the liberation rate of the materials can reach 87.3%. When the density of the suspension is 31,250 g/m(3), the performance of liberation is the best. Two-step magnetic separation was adopted to avoid excessive crushing and to guarantee the quality of products. Concerning both the separation efficiency and grade of products, the optimum rotational speed of the magnetic separator is 50-70 rpm. On the basis of the above studies about the liberating and separating behavior of the materials, a continuous recycling system (the technology of crush-magnetic separation) is developed. This recycling system provides a feasible method for recycling MPP efficiently, economically, and environmentally.

Entropy-driven binding of opioid peptides induces a large domain motion in human dipeptidyl peptidase III

PubMed Central

Bezerra, Gustavo A.; Dobrovetsky, Elena; Viertlmayr, Roland; Dong, Aiping; Binter, Alexandra; Abramić, Marija; Macheroux, Peter; Dhe-Paganon, Sirano; Gruber, Karl

2012-01-01

Opioid peptides are involved in various essential physiological processes, most notably nociception. Dipeptidyl peptidase III (DPP III) is one of the most important enkephalin-degrading enzymes associated with the mammalian pain modulatory system. Here we describe the X-ray structures of human DPP III and its complex with the opioid peptide tynorphin, which rationalize the enzyme's substrate specificity and reveal an exceptionally large domain motion upon ligand binding. Microcalorimetric analyses point at an entropy-dominated process, with the release of water molecules from the binding cleft (“entropy reservoir”) as the major thermodynamic driving force. Our results provide the basis for the design of specific inhibitors that enable the elucidation of the exact role of DPP III and the exploration of its potential as a target of pain intervention strategies. PMID:22493238

Massively Parallel Processing for Fast and Accurate Stamping Simulations

NASA Astrophysics Data System (ADS)

Gress, Jeffrey J.; Xu, Siguang; Joshi, Ramesh; Wang, Chuan-tao; Paul, Sabu

2005-08-01

The competitive automotive market drives automotive manufacturers to speed up the vehicle development cycles and reduce the lead-time. Fast tooling development is one of the key areas to support fast and short vehicle development programs (VDP). In the past ten years, the stamping simulation has become the most effective validation tool in predicting and resolving all potential formability and quality problems before the dies are physically made. The stamping simulation and formability analysis has become an critical business segment in GM math-based die engineering process. As the simulation becomes as one of the major production tools in engineering factory, the simulation speed and accuracy are the two of the most important measures for stamping simulation technology. The speed and time-in-system of forming analysis becomes an even more critical to support the fast VDP and tooling readiness. Since 1997, General Motors Die Center has been working jointly with our software vendor to develop and implement a parallel version of simulation software for mass production analysis applications. By 2001, this technology was matured in the form of distributed memory processing (DMP) of draw die simulations in a networked distributed memory computing environment. In 2004, this technology was refined to massively parallel processing (MPP) and extended to line die forming analysis (draw, trim, flange, and associated spring-back) running on a dedicated computing environment. The evolution of this technology and the insight gained through the implementation of DM0P/MPP technology as well as performance benchmarks are discussed in this publication.

The plastid and mitochondrial peptidase network in Arabidopsis thaliana: a foundation for testing genetic interactions and functions in organellar proteostasis

USDA-ARS?s Scientific Manuscript database

Plant plastids and mitochondria have dynamic proteomes. To maintain their protein homeostasis, a proteostasis network containing protein chaperones, peptidases and their substrate recognition factors exists, but many peptidases, their functional connections and substrates are poorly characterized. T...

Inhibition of DD-peptidases by a specific trifluoroketone: crystal structure of a complex with the Actinomadura R39 DD-peptidase.

PubMed

Dzhekieva, Liudmila; Adediran, S A; Herman, Raphael; Kerff, Frédéric; Duez, Colette; Charlier, Paulette; Sauvage, Eric; Pratt, R F

2013-03-26

Inhibitors of bacterial DD-peptidases represent potential antibiotics. In the search for alternatives to β-lactams, we have investigated a series of compounds designed to generate transition state analogue structures upon reaction with DD-peptidases. The compounds contain a combination of a peptidoglycan-mimetic specificity handle and a warhead capable of delivering a tetrahedral anion to the enzyme active site. The latter includes a boronic acid, two alcohols, an aldehyde, and a trifluoroketone. The compounds were tested against two low-molecular mass class C DD-peptidases. As expected from previous observations, the boronic acid was a potent inhibitor, but rather unexpectedly from precedent, the trifluoroketone [D-α-aminopimelyl(1,1,1-trifluoro-3-amino)butan-2-one] was also very effective. Taking into account competing hydration, we found the trifluoroketone was the strongest inhibitor of the Actinomadura R39 DD-peptidase, with a subnanomolar (free ketone) inhibition constant. A crystal structure of the complex between the trifluoroketone and the R39 enzyme showed that a tetrahedral adduct had indeed formed with the active site serine nucleophile. The trifluoroketone moiety, therefore, should be considered along with boronic acids and phosphonates as a warhead that can be incorporated into new and effective DD-peptidase inhibitors and therefore, perhaps, antibiotics.

Compartmentalized oxidative stress in dopaminergic cell death induced by pesticides and complex I inhibitors: Distinct roles of superoxide anion and superoxide dismutases

PubMed Central

Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Pickett, Chillian; Sumin, Li; Jones, Jocelyn; Chen, Han; Webb, Brian; Choi, Jae; Zhou, You; Zimmerman, Matthew C.; Franco, Rodrigo

2013-01-01

The loss of dopaminergic neurons induced by the parkinsonian toxins paraquat, rotenone and 1-methyl-4-phenylpyridinium (MPP+) is associated with oxidative stress. However, controversial reports exist regarding the source/compartmentalization of reactive oxygen species (ROS) generation and its exact role in cell death. We aimed to determine in detail the role of superoxide anion (O2•−), oxidative stress and their subcellular compartmentalization in dopaminergic cell death induced by parkinsonian toxins. Oxidative stress and ROS formation was determined in the cytosol, intermembrane (IMS) and mitochondrial matrix compartments, using dihydroethidine derivatives, the redox sensor roGFP, as well as electron paramagnetic resonance spectroscopy. Paraquat induced an increase in ROS and oxidative stress in both the cytosol and mitochondrial matrix prior to cell death. MPP+ and rotenone primarily induced an increase in ROS and oxidative stress in the mitochondrial matrix. No oxidative stress was detected at the level of the IMS. In contrast to previous studies, overexpression of manganese superoxide dismutase (MnSOD) or copper/zinc SOD (CuZnSOD) had no effect on ROS steady state levels, lipid peroxidation, loss of mitochondrial membrane potential (ΔΨm) and dopaminergic cell death induced by MPP+ or rotenone. In contrast, paraquat-induced oxidative stress and cell death were selectively reduced by MnSOD overexpression, but not by CuZnSOD or manganese-porphyrins. However, MnSOD also failed to prevent ΔΨm loss. Finally, paraquat, but not MPP+ or rotenone, induced the transcriptional activation the redox-sensitive antioxidant response elements (ARE) and nuclear factor kappa-B (NF-κB). These results demonstrate a selective role of mitochondrial O2•− in dopaminergic cell death induced by paraquat, and show that toxicity induced by the complex I inhibitors rotenone and MPP+ does not depend directly on mitochondrial O2•− formation. PMID:23602909

Plantar pressure in diabetic peripheral neuropathy patients with active foot ulceration, previous ulceration and no history of ulceration: a meta-analysis of observational studies.

PubMed

Fernando, Malindu Eranga; Crowther, Robert George; Pappas, Elise; Lazzarini, Peter Anthony; Cunningham, Margaret; Sangla, Kunwarjit Singh; Buttner, Petra; Golledge, Jonathan

2014-01-01

Elevated dynamic plantar pressures are a consistent finding in diabetes patients with peripheral neuropathy with implications for plantar foot ulceration. This meta-analysis aimed to compare the plantar pressures of diabetes patients that had peripheral neuropathy and those with neuropathy with active or previous foot ulcers. Published articles were identified from Medline via OVID, CINAHL, SCOPUS, INFORMIT, Cochrane Central EMBASE via OVID and Web of Science via ISI Web of Knowledge bibliographic databases. Observational studies reporting barefoot dynamic plantar pressure in adults with diabetic peripheral neuropathy, where at least one group had a history of plantar foot ulcers were included. Interventional studies, shod plantar pressure studies and studies not published in English were excluded. Overall mean peak plantar pressure (MPP) and pressure time integral (PTI) were primary outcomes. The six secondary outcomes were MPP and PTI at the rear foot, mid foot and fore foot. The protocol of the meta-analysis was published with PROPSERO, (registration number CRD42013004310). Eight observational studies were included. Overall MPP and PTI were greater in diabetic peripheral neuropathy patients with foot ulceration compared to those without ulceration (standardised mean difference 0.551, 95% CI 0.290-0.811, p<0.001; and 0.762, 95% CI 0.303-1.221, p = 0.001, respectively). Sub-group analyses demonstrated no significant difference in MPP for those with neuropathy with active ulceration compared to those without ulcers. A significant difference in MPP was found for those with neuropathy with a past history of ulceration compared to those without ulcers; (0.467, 95% CI 0.181- 0.753, p = 0.001). Statistical heterogeneity between studies was moderate. Plantar pressures appear to be significantly higher in patients with diabetic peripheral neuropathy with a history of foot ulceration compared to those with diabetic neuropathy without a history of ulceration. More homogenous data is needed to confirm these findings.

Associations of Maternal Pre-Pregnancy Body Mass Index and Gestational Weight Gain with Adult Offspring Cardio-Metabolic Risk Factors: The Jerusalem Perinatal Family Follow-up Study

PubMed Central

Hochner, Hagit; Friedlander, Yechiel; Calderon-Margalit, Ronit; Meiner, Vardiella; Sagy, Yael; Avgil-Tsadok, Meytal; Burger, Ayala; Savitsky, Bella; Siscovick, David S.; Manor, Orly

2012-01-01

Background Accumulating evidence demonstrates that both maternal pre-pregnancy body mass index (mppBMI) and gestational weight gain (GWG) are associated with adult offspring adiposity. However, whether these maternal attributes are related to other cardio-metabolic risk factors in adulthood has not been comprehensively studied. Methods and Results We used a birth cohort of 1400 young adults born in Jerusalem, with extensive archival data as well as clinical information at age 32, to prospectively examine the associations of mppBMI and GWG with adiposity and related cardio-metabolic outcomes. Greater mppBMI, independent of GWG and confounders, was significantly associated with higher offspring BMI, waist circumference (WC), systolic and diastolic BP, insulin and triglycerides and with lower HDL-C. For example, the effect sizes were translated to nearly 5kg/m2 higher mean BMI, 8.4cm higher WC, 0.13mmol/L (11.4mg/dL) higher triglycerides and 0.10mmol/L (3.8mg/dL) lower HDL-C among offspring of mothers within the upper mppBMI quartile (BMI>26.4kg/m2) compared to the lower (BMI<21.0kg/m2). GWG, independent of mppBMI, was positively associated with offspring adiposity; differences of 1.6kg/m2 in BMI and 2.4cm in waist were observed when offspring of mothers in the upper (GWG>14kg) and lower (GWG<9kg) quartiles of GWG were compared. Further adjustment for offspring adiposity attenuated to null the observed associations. Conclusions Maternal size both before and during pregnancy are associated with cardio-metabolic risk factors in young adult offspring. The associations appear to be driven mainly by offspring adiposity. Future studies that explore mechanisms underlying the intergenerational cycle of obesity are warranted to identify potentially novel targets for cardio-metabolic risk-reduction interventions. PMID:22344037

Development of a Big Data Application Architecture for Navy Manpower, Personnel, Training, and Education

DTIC Science & Technology

2016-03-01

science IT information technology JBOD just a bunch of disks JDBC java database connectivity xviii JPME Joint Professional Military Education JSO...Joint Service Officer JVM java virtual machine MPP massively parallel processing MPTE Manpower, Personnel, Training, and Education NAVMAC Navy...27 external database, whether it is MySQL , Oracle, DB2, or SQL Server (Teller, 2015). Connectors optimize the data transfer by obtaining metadata

An angiotensin-(1–7) peptidase in the kidney cortex, proximal tubules, and human HK-2 epithelial cells that is distinct from insulin-degrading enzyme

PubMed Central

Wilson, Bryan A.; Cruz-Diaz, Nildris; Marshall, Allyson C.; Pirro, Nancy T.; Su, Yixin; Gwathmey, TanYa M.; Rose, James C.

2015-01-01

Angiotensin 1–7 [ANG-(1–7)] is expressed within the kidney and exhibits renoprotective actions that antagonize the inflammatory, fibrotic, and pro-oxidant effects of ANG II. We previously identified an peptidase that preferentially metabolized ANG-(1–7) to ANG-(1–4) in the brain medulla and cerebrospinal fluid (CSF) of sheep (Marshall AC, Pirro NT, Rose JC, Diz DI, Chappell MC. J Neurochem 130: 313–323, 2014); thus the present study established the expression of the peptidase in the kidney. Utilizing a sensitive HPLC-based approach, we demonstrate a peptidase activity that hydrolyzed ANG-(1–7) to ANG-(1–4) in the sheep cortex, isolated tubules, and human HK-2 renal epithelial cells. The peptidase was markedly sensitive to the metallopeptidase inhibitor JMV-390; human HK-2 cells expressed subnanomolar sensitivity (IC50 = 0.5 nM) and the highest specific activity (123 ± 5 fmol·min−1·mg−1) compared with the tubules (96 ± 12 fmol·min−1·mg−1) and cortex (107 ± 9 fmol·min−1·mg−1). The peptidase was purified 41-fold from HK-2 cells; the activity was sensitive to JMV-390, the chelator o-phenanthroline, and the mercury-containing compound p-chloromercuribenzoic acid (PCMB), but not to selective inhibitors against neprilysin, neurolysin and thimet oligopeptidase. Both ANG-(1–7) and its endogenous analog [Ala1]-ANG-(1–7) (alamandine) were preferentially hydrolyzed by the peptidase compared with ANG II, [Asp1]-ANG II, ANG I, and ANG-(1–12). Although the ANG-(1–7) peptidase and insulin-degrading enzyme (IDE) share similar inhibitor characteristics of a metallothiolendopeptidase, we demonstrate marked differences in substrate specificity, which suggest these peptidases are distinct. We conclude that an ANG-(1–7) peptidase is expressed within the renal proximal tubule and may play a potential role in the renal renin-angiotensin system to regulate ANG-(1–7) tone. PMID:25568136

Trypanosoma brucei Metacaspase 4 Is a Pseudopeptidase and a Virulence Factor*

PubMed Central

Proto, William R.; Castanys-Munoz, Esther; Black, Alana; Tetley, Laurence; Moss, Catherine X.; Juliano, Luiz; Coombs, Graham H.; Mottram, Jeremy C.

2011-01-01

Metacaspases are caspase family cysteine peptidases found in plants, fungi, and protozoa but not mammals. Trypanosoma brucei is unusual in having five metacaspases (MCA1–MCA5), of which MCA1 and MCA4 have active site substitutions, making them possible non-enzymatic homologues. Here we demonstrate that recombinant MCA4 lacks detectable peptidase activity despite maintaining a functional peptidase structure. MCA4 is expressed primarily in the bloodstream form of the parasite and associates with the flagellar membrane via dual myristoylation/palmitoylation. Loss of function phenotyping revealed critical roles for MCA4; rapid depletion by RNAi caused lethal disruption to the parasite's cell cycle, yet the generation of MCA4 null mutant parasites (Δmca4) was possible. Δmca4 had normal growth in axenic culture but markedly reduced virulence in mice. Further analysis revealed that MCA4 is released from the parasite and is specifically processed by MCA3, the only metacaspase that is both palmitoylated and enzymatically active. Accordingly, we have identified that the multiple metacaspases in T. brucei form a membrane-associated proteolytic cascade to generate a pseudopeptidase virulence factor. PMID:21949125

Image Understanding Workshop. Proceedings of a Workshop Held in Los Angeles, California on 23-25 February 1987. Volume 2

DTIC Science & Technology

1987-02-25

Modellierung von Kanten bei unregel. Navigation within a building, to be published in IEEE mifliger Rasterung in Bildverarbeitun uand Muster...converted them into equivalent machine cycles in Table 3-1. We took into account of 100 nanosecond 0 - 0, machine cycle time of the MPP. In MPP, NON- VON ...We show the result for the conjugate gradient method in of NON- VON . We assumed that the instructions which carry Table 4-4. The computation of four

Purification and characterization of a tripeptidyl peptidase I from human osteoclastomas: evidence for its role in bone resorption.

PubMed

Page, A E; Fuller, K; Chambers, T J; Warburton, M J

1993-11-01

Tripeptidyl peptidase I (EC 3.4.14.9), which cleaves tripeptides from the N-terminus of synthetic substrates, has been purified from human osteoclastomas (a bone tumor containing large numbers of normal osteoclasts). The enzyme has an M(r) of 48 kDa but forms aggregates with an M(r) of about 700 kDa. The tripeptidyl peptidase has an acidic pH optimum (approximately pH 5.0), suggesting that it has a lysosomal localization and prefers substrates with a hydrophobic amino acid in the P1 position. There is an absolute requirement for a nonsubstituted N-terminus. The enzyme is inhibited by reagents which modify serine and histidine residues. Lysosomal tripeptidyl peptidase is known to be capable of cleaving Gly-Pro-X triplets from synthetic collagen-like polypeptides. Ala-Ala-Phe-CH2Cl, a potent inhibitor of osteoclastoma tripeptidyl peptidase, inhibits osteoclastic bone resorption in an in vitro test system. This suggests that tripeptidyl peptidase I, secreted by osteoclasts, is involved at some stage in the degradation of bone collagen.

Evolution of the thermopsin peptidase family (A5).

PubMed

Rawlings, Neil D

2013-01-01

Thermopsin is a peptidase from Sulfolobus acidocaldarius that is active at low pH and high temperature. From reversible inhibition with pepstatin, thermopsin is thought to be an aspartic peptidase. It is a member of the only family of peptidases to be restricted entirely to the archaea, namely peptidase family A5. Evolution within this family has been mapped, using a taxonomic tree based on the known classification of archaea. Homologues are found only in archaeans that are both hyperthermophiles and acidophiles, and this implies lateral transfer of genes between archaea, because species with homologues are not necessarily closely related. Despite the remarkable stability and activity in extreme conditions, no tertiary structure has been solved for any member of the family, and the catalytic mechanism is unknown. Putative catalytic residues have been predicted here by examination of aligned sequences.

Altered levels of acid, basic, and neutral peptidase activity and expression in human clear cell renal cell carcinoma.

PubMed

Varona, Adolfo; Blanco, Lorena; López, José I; Gil, Javier; Agirregoitia, Ekaitz; Irazusta, Jon; Larrinaga, Gorka

2007-02-01

Peptides play important roles in cell regulation and signaling in many tissues and are regulated by peptidases, most of which are highly expressed in the kidney. Several peptide convertases have a function in different tumor stages, and some have been clearly characterized as diagnostic and prognostic markers for solid tumors, including renal cancer; however, little is known about their in vivo role in kidney tumors. The present study compares the activity of a range of peptidases in human tumor samples and nontumor tissue obtained from clear cell renal cell carcinoma (CCRCC) patients. To cover the complete spectrum and subcellular distribution of peptide-converting activity, acid, neutral, basic, and omega activities were selected. CCRCC displays a selective and restricted pattern of peptidase activities. Puromycin-sensitive aminopeptidase activity in the tumor increases [tumor (t) = 10,775 vs. nontumor (n) = 7,635 units of peptidase (UP)/mg protein; P < 0.05], whereas aminopeptidase N decreases (t = 6,664 vs. n = 33,381 UP/mg protein; P < 0.001). Aminopeptidase B activity of the particulate fraction in tumors decreases (t = 2,399 vs. n = 13,536 UP/mg protein; P < 0.001) compared with nontumor tissues, and aspartyl-aminopeptidase activity decreases significantly in CCRCC (t = 137 vs. n = 223 UP/mg protein; P < 0.05). Soluble and particulate pyroglutamyl peptidase I activities, aminopeptidase A activity, and soluble aminopeptidase B activity do not vary in renal cancer. The relative expression for the aforementioned peptidases, assayed using quantitative RT-PCR, increases in CCRCC for aminopeptidases B (1.5-fold) and A (19-fold), aspartyl-aminopeptidase (3.9-fold), puromycin-sensitive aminopeptidase (2.5-fold), and pyroglutamyl peptidase I (7.6-fold). Only aminopeptidase N expression decreases in tumors (1.3-fold). This peptidase activity profile in the neoplastic kidney suggests a specific role for the studied convertases and the possible involvement of an intracrine renin-angiotensin system in the pathogenesis of CCRCC.

Protection by serine peptidase inhibitors of endogenous cholecystokinin released from brain slices.

PubMed

Rose, C; Camus, A; Schwartz, J C

1989-01-01

Endogenous cholecystokinin immunoreactivity released by depolarization of slices of rat cerebral cortex undergoes extensive degradation (85% of released immunoreactivity) before reaching the incubation medium. In order to identify the responsible peptidases, a large number of inhibitors of the four catalytic classes were tested for their protective effects. Inhibitors of metallopeptidases (bestatin, amastatin, puromycin, Thiorphan, captopril, o-phenantroline), thiol-peptidases, (leupeptin, antipain, p-hydroxymercuribenzoate) or carboxyl-peptidases (pepstatin) had generally low if any protective effect. By contrast, several serine peptidase inhibitors, i.e. diisopropyl-fluorophosphate, phenylmethylsulphonylfluoride or the chloromethylketone Ala-Ala-Pro-Val-CH2Cl, doubled the recovery of cholecystokinin immunoreactivity and the effect was amplified in the co-presence of bestatin, an aminopeptidase inhibitor and/or Thiorphan, an enkephalinase inhibitor. High-performance liquid chromatographic analysis of the cholecystokinin immunoreactivity recovered in medium in the absence of any inhibitor showed cholecystokinin-8 to be the major peak, representing 8% of the released immunoreactive material. Non-sulphated cholecystokinin-8 represented less than 1%, indicating that desulphation does not constitute a major inactivation pathway for the endogenous octapeptide. Cholecystokinin-5 was the major clearly identifiable immunoreactive fragment, representing 9% of released immunoreactivity in the absence of inhibitors. Its formation was decreased by about 50% in the presence of either diisopropyl-fluorophosphate or bestatin and Thiorphan and abolished when they were associated, suggesting that it resulted from the actions of a serine peptidase(s) and an aminopeptidase(s). Cholecystokinin-6 (or cholecystokinin-7) was less abundant, representing 4% of the released immunoreactivity, and its level was augmented in the presence of diisopropyl-fluorophosphate. Hence a serine endopeptidase cleaving the Met3-Gly4 bond of cholecystokinin-8 may represent a major inactivating peptidase for the endogenous neuropeptide. Additional metabolic pathways not blocked by serine peptidase inhibitors and resulting in the formation of cholecystokinin-6 (or cholecystokinin-7) and, possibly, cholecystokinin-4, are also suggested by the present approach.

Implementation and analysis of a Navier-Stokes algorithm on parallel computers

NASA Technical Reports Server (NTRS)

Fatoohi, Raad A.; Grosch, Chester E.

1988-01-01

The results of the implementation of a Navier-Stokes algorithm on three parallel/vector computers are presented. The object of this research is to determine how well, or poorly, a single numerical algorithm would map onto three different architectures. The algorithm is a compact difference scheme for the solution of the incompressible, two-dimensional, time-dependent Navier-Stokes equations. The computers were chosen so as to encompass a variety of architectures. They are the following: the MPP, an SIMD machine with 16K bit serial processors; Flex/32, an MIMD machine with 20 processors; and Cray/2. The implementation of the algorithm is discussed in relation to these architectures and measures of the performance on each machine are given. The basic comparison is among SIMD instruction parallelism on the MPP, MIMD process parallelism on the Flex/32, and vectorization of a serial code on the Cray/2. Simple performance models are used to describe the performance. These models highlight the bottlenecks and limiting factors for this algorithm on these architectures. Finally, conclusions are presented.

Cysteine peptidases from Phytomonas serpens: biochemical and immunological approaches.

PubMed

Elias, Camila G R; Aor, Ana Carolina; Valle, Roberta S; d'Avila-Levy, Claudia M; Branquinha, Marta H; Santos, André L S

2009-12-01

Phytomonas serpens, a phytoflagellate trypanosomatid, shares common antigens with Trypanosoma cruzi. In the present work, we compared the hydrolytic capability of cysteine peptidases in both trypanosomatids. Trypanosoma cruzi epimastigotes presented a 10-fold higher efficiency in hydrolyzing the cysteine peptidase substrate Z-Phe-Arg-AMC than P. serpens promastigotes. Moreover, two weak cysteine-type gelatinolytic activities were detected in P. serpens, while a strong 50-kDa cysteine peptidase was observed in T. cruzi. Cysteine peptidase activities were detected at twofold higher levels in the cytoplasmic fraction when compared with the membrane-rich or the content released from P. serpens. The cysteine peptidase secreted by P. serpens cleaved several proteinaceous substrates. Corroborating these findings, the cellular distribution of the cruzipain-like molecules in P. serpens was attested through immunocytochemistry analysis. Gold particles were observed in all cellular compartments, including the cytoplasm, plasma membrane, flagellum, flagellar membrane and flagellar pocket. Interestingly, some gold particles were visualized free in the flagellar pocket, suggesting the release of the cruzipain-like molecule. The antigenic properties of the cruzipain-like molecules of P. serpens were also analyzed. Interestingly, sera from chagasic patients recognized both cellular and extracellular antigens of P. serpens, including the cruzipain-like molecule. These results point to the use of P. serpens antigens, especially the cruzipain-like cysteine-peptidases, as an alternative vaccination approach to T. cruzi infection.

An Internal Signal Sequence Directs Intramembrane Proteolysis of a Cellular Immunoglobulin Domain Protein*S⃞

PubMed Central

Robakis, Thalia; Bak, Beata; Lin, Shu-huei; Bernard, Daniel J.; Scheiffele, Peter

2008-01-01

Precursor proteolysis is a crucial mechanism for regulating protein structure and function. Signal peptidase (SP) is an enzyme with a well defined role in cleaving N-terminal signal sequences but no demonstrated function in the proteolysis of cellular precursor proteins. We provide evidence that SP mediates intraprotein cleavage of IgSF1, a large cellular Ig domain protein that is processed into two separate Ig domain proteins. In addition, our results suggest the involvement of signal peptide peptidase (SPP), an intramembrane protease, which acts on substrates that have been previously cleaved by SP. We show that IgSF1 is processed through sequential proteolysis by SP and SPP. Cleavage is directed by an internal signal sequence and generates two separate Ig domain proteins from a polytopic precursor. Our findings suggest that SP and SPP function are not restricted to N-terminal signal sequence cleavage but also contribute to the processing of cellular transmembrane proteins. PMID:18981173

Mitochondrial complex I inhibition is not required for dopaminergic neuron death induced by rotenone, MPP+, or paraquat

PubMed Central

Choi, Won-Seok; Kruse, Shane E.; Palmiter, Richard D.; Xia, Zhengui

2008-01-01

Inhibition of mitochondrial complex I is one of the leading hypotheses for dopaminergic neuron death associated with Parkinson's disease (PD). To test this hypothesis genetically, we used a mouse strain lacking functional Ndufs4, a gene encoding a subunit required for complete assembly and function of complex I. Deletion of the Ndufs4 gene abolished complex I activity in midbrain mesencephalic neurons cultured from embryonic day (E) 14 mice, but did not affect the survival of dopaminergic neurons in culture. Although dopaminergic neurons were more sensitive than other neurons in these cultures to cell death induced by rotenone, MPP+, or paraquat treatments, the absence of complex I activity did not protect the dopaminergic neurons, as would be expected if these compounds act by inhibiting complex 1. In fact, the dopaminergic neurons were more sensitive to rotenone. These data suggest that dopaminergic neuron death induced by treatment with rotenone, MPP+, or paraquat is independent of complex I inhibition. PMID:18812510

Bayesian characterization of micro-perforated panels and multi-layer absorbers

NASA Astrophysics Data System (ADS)

Schmitt, Andrew Alexander Joseph

First described by the late acoustician Dah-You Maa, micro-perforated panel (MPP) absorbers produce extremely high acoustic absorption coefficients. This is done without the use of conventional fibrous or porous materials that are often used in acoustic treatments, meaning MPP absorbers are capable of being implemented and withstanding critical situations where traditional absorbers do not suffice. The absorption function of a micro-perforated panel yields high yet relatively narrow results at certain frequencies, although wide-band absorption can be designed by stacking multiple MPP absorbers comprised of different characteristic parameters. Using Bayesian analysis, the physical properties of panel thickness, pore diameter, perforation ratio, and air depth are estimated inversely from experimental data of acoustic absorption, based on theoretical models for design of micro-perforated panels. Furthermore, this analysis helps to understand the interdependence and uncertainties of the parameters and how each affects the performance of the panel. Various micro-perforated panels are manufactured and tested in single- and double-layer absorber constructions.

Alterations in Glutathione S-transferase pi expression following exposure to MPP+-induced oxidative stress in blood of Parkinson’s disease patients

PubMed Central

Korff, Ane; Pfeiffer, Brenda; Smeyne, Michelle; Kocak, Mehmet; Pfeiffer, Ronald F.

2012-01-01

The major motor symptoms of Parkinson’s disease do not occur until a majority of the dopaminergic neurons in the midbrain SNpc have already died. For this reason, it is critical to identify biomarkers that will allow for the identification of presymptomatic individuals. In this study, we examine the baseline expression of the antioxidant protein Glutathione S-transferase pi (GSTpi) in blood of PD and environmental and age-matched controls and compare it to GSTpi levels following exposure to 1-methyl-4-phenylpyridinium (MPP+), an agent that has been shown to induce oxidative stress. We find that 4 hours of exposure to MPP+, significant increases in GSTpi levels can be observed in the leukocytes of PD patients. No changes were seen in other blood components. This suggests that GSTpi and potentially other members of this and other anti-oxidant families may be viable biomarkers for PD. PMID:21840241

Alterations in glutathione S-transferase pi expression following exposure to MPP+ -induced oxidative stress in the blood of Parkinson's disease patients.

PubMed

Korff, Ane; Pfeiffer, Brenda; Smeyne, Michelle; Kocak, Mehmet; Pfeiffer, Ronald F; Smeyne, Richard Jay

2011-12-01

The major motor symptoms of Parkinson's disease do not occur until a majority of the dopaminergic neurons in the midbrain SNpc have already died. For this reason, it is critical to identify biomarkers that will allow for the identification of presymptomatic individuals. In this study, we examine the baseline expression of the anti-oxidant protein glutathione S-transferase pi (GSTpi) in the blood of PD patients and environmentally- and age-matched controls and compare it to GSTpi levels following exposure to 1-methyl-4-phenylpyridinium (MPP(+)), an agent that has been shown to induce oxidative stress. We find that after 4 h of exposure to MPP(+), significant increases in GSTpi levels can be observed in the leukocytes of PD patients. No changes were seen in other blood components. This suggests that GSTpi and potentially other members of this and other anti-oxidant families may be viable biomarkers for PD. Copyright © 2011 Elsevier Ltd. All rights reserved.

Four years of lessons learned: The 2001-2004 Maryland influenza prevention seasons.

PubMed

Tate, Tiffany

2006-01-01

More than 36,000 Americans die and 200,000 more are hospitalized because of influenza every\\year. Despite the wide availability of a vaccine to prevent influenza, the vast majority of Americans go unimmunized. The Maryland Department of Health and Mental Hygiene (DHMH) and the Maryland Partnership for Prevention (MPP) collect data about the state's local health departments' influenza season practices and experiences and compile them into the annual Maryland Influenza Season Final Report. The report becomes a tool for DHMH, MPP, and the state's 24 local health departments to plan improvements in influenza vaccination services. This article chronicles four influenza seasons. Influenza season challenges experienced in three of the last four influenza seasons underscore the importance of coordination and communication efforts to ensure that vaccine is efficiently delivered to the most vulnerable populations. The partnership between DHMH and MPP has facilitated access to information on ordering and administration practices, communication systems, community partnerships, and lessons learned, thus enabling the state of Maryland to continually optimize its influenza vaccination promotion efforts.

Amphetamine-metabolites of deprenyl involved in protection against neurotoxicity induced by MPTP and 2'-methyl-MPTP.

PubMed

Sziráki, I; Kardos, V; Patthy, M; Pátfalusi, M; Gaál, J; Solti, M; Kollár, E; Singer, J

1994-01-01

The ability of 1-deprenyl to protect against the parkinsonian effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been attributed to the inhibition of conversion of MPTP to MPP+ (1-methyl-4-phenylpyridinium) catalyzed by MAO-B. We report here that deprenyl-treatment in mice has an additional neuroprotective element associated with the rapid metabolization of 1-deprenyl to 1-methamphetamine and 1-amphetamine. 1-Methamphetamine and 1-amphetamine inhibit MPP(+)-uptake into striatal synaptosomes prepared from rats. Post-treatment by 1-deprenyl, 1-methamphetamine, 1-amphetamine (at times when MPTP is no longer present in the striatum of mice) protects against neurotoxicity in C57BL mice by blocking the uptake of MPP+ into dopaminergic neurons, and even against the neurotoxicity induced by 2'CH3-MPTP, which is partly bioactivated by MAO-A. These findings may have clinical implications since deprenyl has recently been found to delay the progression of Parkinson's disease.

Laboratory experiments on simultaneous removal of K and P from synthetic and real urine for nutrient recycle by crystallization of magnesium-potassium-phosphate-hexahydrate in a draft tube and baffle reactor.

PubMed

Xu, Kangning; Wang, Chengwen; Wang, Xiaoxue; Qian, Yi

2012-06-01

The simultaneous removal of K and P from urine for nutrient recycling by crystallization of magnesium potassium phosphate hexahydrate (MPP) in a laboratory-scale draft tube and baffle reactor (DTBR) is investigated. Results show that mixing speed and hydraulic retention time are important operating factors that influence crystallization and crystal settlement. Slurry should be discharged at a crystal retention time of 11 h to maintain fluidity in the reactor. Further applications of the DTBR using real urine (pretreated by ammonia stripping and diluted five times) showed that 76% K and 68% P were recycled to multi-nutrient products. The crystals collected were characterized and confirmed mainly as a mixture of magnesium ammonium phosphate hexahydrate, MPP, and magnesium sodium phosphate heptahydrate. Results indicate that the DTBR effectively achieved the simultaneous recycling of K and P from urine to multi-nutrient products through MPP crystallization. Copyright © 2012 Elsevier Ltd. All rights reserved.

HvPap-1 C1A Protease and HvCPI-2 Cystatin Contribute to Barley Grain Filling and Germination.

PubMed

Diaz-Mendoza, Mercedes; Dominguez-Figueroa, Jose D; Velasco-Arroyo, Blanca; Cambra, Ines; Gonzalez-Melendi, Pablo; Lopez-Gonzalvez, Angeles; Garcia, Antonia; Hensel, Goetz; Kumlehn, Jochen; Diaz, Isabel; Martinez, Manuel

2016-04-01

Proteolysis is an essential process throughout the mobilization of storage proteins in barley (Hordeum vulgare) grains during germination. It involves numerous types of enzymes, with C1A Cys proteases the most abundant key players. Manipulation of the proteolytic machinery is a potential way to enhance grain yield and quality, and it could influence the mobilization of storage compounds along germination. Transgenic barley plants silencing or over-expressing the cathepsin F-like HvPap-1 Cys protease show differential accumulation of storage molecules such as starch, proteins, and free amino acids in the grain. It is particularly striking that the HvPap-1 artificial microRNA lines phenotype show a drastic delay in the grain germination process. Alterations to the proteolytic activities in the over-expressing and knock-down grains associated with changes in the level of expression of several C1A peptidases were also detected. Similarly, down-regulating cystatin Icy-2, one of the proteinaceous inhibitors of the cathepsin F-like protease, also has important effects on grain filling. However, the ultimate physiological influence of manipulating a peptidase or an inhibitor cannot be always predicted, since the plant tries to compensate the modified proteolytic effects by modulating the expression of some other peptidases or their inhibitors. © 2016 American Society of Plant Biologists. All Rights Reserved.

Bacillus thuringiensis Cry3Aa protoxin intoxication of Tenebrio molitor induces widespread changes in the expression of serine peptidase transcripts

USDA-ARS?s Scientific Manuscript database

The yellow mealworm, Tenebrio molitor, is a pest of stored grain products and is sensitive to the coleopteran-specific Cry3Aa toxin from Bacillus thuringiensis (Bt). Larvae digest protein initially with cysteine peptidases in the anterior midgut and further with serine peptidases in middle and poste...

Core protein cleavage by signal peptide peptidase is required for hepatitis C virus-like particle assembly

PubMed Central

Ait-Goughoulte, Malika; Hourioux, Christophe; Patient, Romuald; Trassard, Sylvie; Brand, Denys; Roingeard, Philippe

2006-01-01

SUMMARY Hepatitis C virus (HCV) core protein, expressed with a Semliki forest virus (SFV) replicon, self-assembles into HCV-like particles (HCV-LP) at the endoplasmic reticulum (ER) membrane, providing an opportunity to study HCV assembly and morphogenesis by electron microscopy. We used this model to investigate whether the processing of the HCV core protein by the signal peptide peptidase (SPP) is required for the HCV-LP assembly. We designed several mutants as there are conflicting reports concerning the cleavage of mutant proteins by SPP. Production of the only core mutant protein that escaped SPP processing led to the formation of multiple layers of electron-dense ER membrane, with no evidence of HCV-LP assembly. Our data shed light on the HCV core residues involved in SPP cleavage and suggest that this cleavage is essential for HCV assembly. PMID:16528035

Dipeptidyl peptidase-4 inhibitor induced angioedema - an overlooked and potentially lethal adverse drug reaction?

PubMed

Scott, Susanne Irene; Andersen, Michelle Fog; Aagaard, Lise; Buchwald, Christian Von; Rasmussen, Eva Rye

2017-02-14

Introduction Angioedema is a potentially fatal adverse drug reaction of some medications, as swellings of the upper airways can cause death by asphyxiation. Angiotensin converting enzyme-inhibitors are widely known to cause angioedema but less is known about the association between dipeptidyl peptidase-4 inhibitors (gliptins) and angioedema. Dipeptidyl peptidase-4 inhibitors are anti-diabetic drugs used to improve glycaemic control. They, as a class effect, inadvertently affect the degradation of the vasoactive kinins bradykinin and substance P, both of which can cause angioedema due to vasodilatation and increase in vascular permeability in the capillaries. Objective To assess the risk and pathomechanism of angioedema due to inhibition of dipeptidyl peptidase-4 inhibitors when used as monotherapy and in combination with angiotensin converting enzyme-inhibitors. Method PubMed, Embase, the Cochrane Library, PubMed Central, Web of Science, Google Scholar and clinicaltrials.gov were searched using different combinations of keywords "angioedema", "dipeptidyl peptidase 4", "dipeptidyl peptidase 4 inhibitors", "gliptins", "bradykinin", "substance P" and "angiotensin converting enzyme-inhibitors". Original research papers were preferably used as references and their bibliographies were used to further the search for original research results. Results Both angiotensin converting enzyme and dipeptidyl peptidase-4 are major enzymes in the degradation pathway of bradykinin and substance P, and when inhibited pharmacologically - especially at the same time - the theoretical risk of angioedema is increased due to accumulation of vasoactive kinins. Conclusion Treatment with dipeptidyl peptidase-4 inhibitors must be carefully considered and monitored especially during concurrent treatment with angiotensin converting enzyme-inhibitors or when treating patients with a known predisposition to angioedema. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The effect of removing plugs and adding arch support to foam based insoles on plantar pressures in people with diabetic peripheral neuropathy.

PubMed

Lin, Tung-Liang; Sheen, Huey-Min; Chung, Chin-Teng; Yang, Sai-Wei; Lin, Shih-Yi; Luo, Hong-Ji; Chen, Chung-Yu; Chan, I-Cheng; Shih, Hsu-Sheng; Sheu, Wayne Huey-Herng

2013-07-29

Removable plug insoles appear to be beneficial for patients with diabetic neuropathic feet to offload local plantar pressure. However, quantitative evidence of pressure reduction by means of plug removal is limited. The value of additional insole accessories, such as arch additions, has not been tested. The purpose of this study was to evaluate the effect of removing plugs from foam based insoles, and subsequently adding extra arch support, on plantar pressures. In-shoe plantar pressure measurements were performed on 26 patients with diabetic neuropathic feet at a baseline condition, in order to identify the forefoot region with the highest mean peak pressure (MPP). This was defined as the region of interest (ROI) for plug removal.The primary outcome was measurement of MPP using the pedar® system in the baseline and another three insole conditions (pre-plug removal, post-plug removal, and post-plug removal plus arch support). Among the 26 ROIs, a significant reduction in MPP (32.3%, P<0.001) was found after removing the insole plugs. With an arch support added, the pressure was further reduced (9.5%, P<0.001). There were no significant differences in MPP at non-ROIs between pre- and post-plug removal conditions. These findings suggest that forefoot plantar pressure can be reduced by removing plugs and adding arch support to foam-based insoles. This style of insole may therefore be clinically useful in managing patients with diabetic peripheral neuropathy.

Sound attenuation and absorption by micro-perforated panels backed by anisotropic fibrous materials: Theoretical and experimental study

NASA Astrophysics Data System (ADS)

Bravo, Teresa; Maury, Cédric

2018-07-01

Enhancing the attenuation or the absorption of low-frequency noise using lightweight bulk-reacting liners is still a demanding task in surface and air transport systems. The aim of this study is to understand the physical mechanisms involved in the attenuation and absorption properties of partitions made up of a thin micro-perforated panel (MPP) rigidly backed by a cavity filled with anisotropic fibrous material. Such a layout is denoted as a MPPF partition. Analytical models are formulated in the flow and no-flow cases to predict the axial damping of the least attenuated wave in a MPPF partition as well as the plane wave absorption coefficient. They account for a rigid or an elastic MPP facing a bulk-reacting fully-anisotropic material. A cost-efficient solution of the propagation constant for the least attenuated mode is obtained using a simulated annealing search method as well as a low-frequency approximation to the axial attenuation. The normal incidence absorption model is assessed in the no-flow case against pressure-velocity measurements of the surface impedance over a MPPF partition filled with fibreglass material. A parametric study is conducted to evaluate the MPP and the cavity constitutive parameters that mostly enhance the axial attenuation and sound absorption properties, with special interest on the MPP airframe relative velocity. This sensitivity study provides guidelines that could be used to further reduce the search space in parametric or impedance optimization studies.

Enduring medial perforant path short-term synaptic depression at high pressure.

PubMed

Talpalar, Adolfo E; Giugliano, Michele; Grossman, Yoram

2010-01-01

The high pressure neurological syndrome develops during deep-diving (>1.1 MPa) involving impairment of cognitive functions, alteration of synaptic transmission and increased excitability in cortico-hippocampal areas. The medial perforant path (MPP), connecting entorhinal cortex with the hippocampal formation, displays synaptic frequency-dependent-depression (FDD) under normal conditions. Synaptic FDD is essential for specific functions of various neuronal networks. We used rat cortico-hippocampal slices and computer simulations for studying the effects of pressure and its interaction with extracellular Ca(2+) ([Ca(2+)](o)) on FDD at the MPP synapses. At atmospheric pressure, high [Ca(2+)](o) (4-6 mM) saturated single MPP field EPSP (fEPSP) and increased FDD in response to short trains at 50 Hz. High pressure (HP; 10.1 MPa) depressed single fEPSPs by 50%. Increasing [Ca(2+)](o) to 4 mM at HP saturated synaptic response at a subnormal level (only 20% recovery of single fEPSPs), but generated a FDD similar to atmospheric pressure. Mathematical model analysis of the fractions of synaptic resources used by each fEPSP during trains (normalized to their maximum) and the total fraction utilized within a train indicate that HP depresses synaptic activity also by reducing synaptic resources. This data suggest that MPP synapses may be modulated, in addition to depression of single events, by reduction of synaptic resources and then may have the ability to conserve their dynamic properties under different conditions.

Enduring Medial Perforant Path Short-Term Synaptic Depression at High Pressure

PubMed Central

Talpalar, Adolfo E.; Giugliano, Michele; Grossman, Yoram

2010-01-01

The high pressure neurological syndrome develops during deep-diving (>1.1 MPa) involving impairment of cognitive functions, alteration of synaptic transmission and increased excitability in cortico-hippocampal areas. The medial perforant path (MPP), connecting entorhinal cortex with the hippocampal formation, displays synaptic frequency-dependent-depression (FDD) under normal conditions. Synaptic FDD is essential for specific functions of various neuronal networks. We used rat cortico-hippocampal slices and computer simulations for studying the effects of pressure and its interaction with extracellular Ca2+ ([Ca2+]o) on FDD at the MPP synapses. At atmospheric pressure, high [Ca2+]o (4–6 mM) saturated single MPP field EPSP (fEPSP) and increased FDD in response to short trains at 50 Hz. High pressure (HP; 10.1 MPa) depressed single fEPSPs by 50%. Increasing [Ca2+]o to 4 mM at HP saturated synaptic response at a subnormal level (only 20% recovery of single fEPSPs), but generated a FDD similar to atmospheric pressure. Mathematical model analysis of the fractions of synaptic resources used by each fEPSP during trains (normalized to their maximum) and the total fraction utilized within a train indicate that HP depresses synaptic activity also by reducing synaptic resources. This data suggest that MPP synapses may be modulated, in addition to depression of single events, by reduction of synaptic resources and then may have the ability to conserve their dynamic properties under different conditions. PMID:21048901

1-Methyl-4-phenylpyridinium-induced alterations of glutathione status in immortalized rat dopaminergic neurons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drechsel, Derek A.; Liang, L.-P.; Patel, Manisha

2007-05-01

Decreased glutathione levels associated with increased oxidative stress are a hallmark of numerous neurodegenerative diseases, including Parkinson's disease. GSH is an important molecule that serves as an anti-oxidant and is also a major determinant of cellular redox environment. Previous studies have demonstrated that neurotoxins can cause changes in reduced and oxidized GSH levels; however, information regarding steady state levels remains unexplored. The goal of this study was to characterize changes in cellular GSH levels and its regulatory enzymes in a dopaminergic cell line (N27) following treatment with the Parkinsonian toxin, 1-methyl-4-phenylpyridinium (MPP{sup +}). Cellular GSH levels were initially significantly decreasedmore » 12 h after treatment, but subsequently recovered to values greater than controls by 24 h. However, oxidized glutathione (GSSG) levels were increased 24 h following treatment, concomitant with a decrease in GSH/GSSG ratio prior to cell death. In accordance with these changes, ROS levels were also increased, confirming the presence of oxidative stress. Decreased enzymatic activities of glutathione reductase and glutamate-cysteine ligase by 20-25% were observed at early time points and partly account for changes in GSH levels after MPP{sup +} exposure. Additionally, glutathione peroxidase activity was increased 24 h following treatment. MPP{sup +} treatment was not associated with increased efflux of glutathione to the medium. These data further elucidate the mechanisms underlying GSH depletion in response to the Parkinsonian toxin, MPP{sup +}.« less

Naringin protects the nigrostriatal dopaminergic projection through induction of GDNF in a neurotoxin model of Parkinson's disease.

PubMed

Leem, Eunju; Nam, Jin Han; Jeon, Min-Tae; Shin, Won-Ho; Won, So-Yoon; Park, Sang-Joon; Choi, Myung-Sook; Jin, Byung Kwan; Jung, Un Ju; Kim, Sang Ryong

2014-07-01

This study investigated the effect of naringin, a major flavonoid in grapefruit and citrus fruits, on the degeneration of the nigrostriatal dopaminergic (DA) projection in a neurotoxin model of Parkinson's disease (PD) in vivo and the potential underlying mechanisms focusing on the induction of glia-derived neurotrophic factor (GDNF), well known as an important neurotrophic factor involved in the survival of adult DA neurons. 1-Methyl-4-phenylpyridinium (MPP(+)) was unilaterally injected into the medial forebrain bundle of rat brains for a neurotoxin model of PD in the presence or absence of naringin by daily intraperitoneal injection. To ascertain whether naringin-induced GDNF contributes to neuroprotection, we further investigated the effects of intranigral injection of neutralizing antibodies against GDNF in the MPP(+) rat model of PD. Our observations demonstrate that naringin could increase the level of GDNF in DA neurons, contributing to neuroprotection in the MPP(+) rat model of PD, with activation of mammalian target of rapamycin complex 1. Moreover, naringin could attenuate the level of tumor necrosis factor-α in microglia increased by MPP(+)-induced neurotoxicity in the substantia nigra. These results indicate that naringin could impart to DA neurons the important ability to produce GDNF as a therapeutic agent against PD with anti-inflammatory effects, suggesting that naringin is a beneficial natural product for the prevention of DA degeneration in the adult brain. Copyright © 2014 Elsevier Inc. All rights reserved.

Vitexin protects dopaminergic neurons in MPTP-induced Parkinson’s disease through PI3K/Akt signaling pathway

PubMed Central

Hu, Ming; Li, Fangming; Wang, Weidong

2018-01-01

Parkinson’s disease (PD) is a progressive neurodegenerative disease which is characterized by the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Methods In this study, the neuroprotective effect of vitexin (Vit), a flavonoid compound isolated from Crataegus pinnatifida Bunge was examined in PD models both in vitro and in vivo. Results On SH-SY5Y cells, methyl-4-phenylpyridine (MPP+) treatment suppressed cell viability, induced apoptosis, and increased Bax/Bcl-2 ratio and caspase-3 activity. However, Vit improved these parameters induced by MPP+ treatment significantly. Further study disclosed that Vit enhanced the phosphorylation of PI3K and Akt which was downregulated by MPP+ in SH-SY5Y cells, the effect of which could be blocked by PI3K inhibitor LY294002 and activated by PI3K activator IGF-1. Moreover, results from the pole test and traction test suggested that Vit pretreatment prevented bradykinesia and alleviated the initial lesions caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in MPTP-treated mouse PD model. Vit also enhanced the activation of PI3K and Akt and suppressed the ratio of Bax/Bcl-2 and caspase-3 activity in MPTP-treated mice. Conclusion Taken together, this study demonstrated that Vit protected dopaminergic neurons against MPP+/MPTP-induced neurotoxicity through the activation of PI3K/Akt signaling pathway. Our findings may facilitate the clinical application of Vit in the therapy of PD. PMID:29588573

Biased expression, under the control of single promoter, of human interferon α-2b and Escherichia coli methionine amino peptidase genes in E. coli, irrespective of their distance from the promoter.

PubMed

Arif, Amina; Rashid, Naeem; Aslam, Farheen; Mahmood, Nasir; Akhtar, Muhammad

2016-03-01

Human interferon α-2b and Escherichia coli methionine amino peptidase genes were cloned independently as well as bicistronically in expression plasmid pET-21a (+). Production of human interferon α-2b was comparable to that of E. coli methionine amino peptidase when these genes were expressed independently in E. coli BL21-CodonPlus (DE3)-RIL. However, human interferon α-2b was produced in a much less amount whereas there was no difference in the production of methionine amino peptidase when the encoding genes were expressed bicistronically. It is important to note that human interferon α-2b was the first gene in order, after the promoter and E. coli methionine amino peptidase was the next with a linker sequence of 27 nucleotides between them.

Role of PSMA in Aberrant Cell Cycle Progression in Prostate Cancer

DTIC Science & Technology

2004-12-01

playing a role in nutrient uptake, and a peptidase involved in signal transduction in prostate epithelial cells. Insights into possible functions of PSMA...should improve the diagnostic and therapeutic values of this clinically important molecule. prostate cancer; receptor; peptidase ; endocytosis 2 OVERVIEW... peptidase activities hydrolyze gamma-peptide bonds between N-acetylaspartate and glutamate in the abundant neuropeptide N-acetylaspartylglutamate

Strategies in the design of small-molecule fluorescent probes for peptidases.

PubMed

Chen, Laizhong; Li, Jing; Du, Lupei; Li, Minyong

2014-11-01

Peptidases, which can cleave specific peptide bonds in innumerable categories of substrates, usually present pivotal positions in protein activation, cell signaling and regulation as well as in the origination of amino acids for protein generation or application in other metabolic pathways. They are also involved in many pathological conditions, such as cancer, atherosclerosis, arthritis, and neurodegenerative disorders. This review article aims to conduct a wide-ranging survey on the development of small-molecule fluorescent probes for peptidases, as well as to realize the state of the art in the tailor-made probes for diverse types of peptidases. © 2014 Wiley Periodicals, Inc.

Substrate specificity of bacterial DD-peptidases (penicillin-binding proteins).

PubMed

Pratt, R F

2008-07-01

The DD-peptidase enzymes (penicillin-binding proteins) catalyze the final transpeptidation reaction of bacterial cell wall (peptidoglycan) biosynthesis. Although there is now much structural information available about these enzymes, studies of their activity as enzymes lag. It is now established that representatives of two low-molecular-mass classes of DD-peptidases recognize elements of peptidoglycan structure and rapidly react with substrates and inhibitors incorporating these elements. No members of other DD-peptidase classes, including the high-molecular-mass enzymes, essential for bacterial growth, appear to interact strongly with any particular elements of peptidoglycan structure. Rational design of inhibitors for these enzymes is therefore challenging.

Characterization of endopeptidase activity of tripeptidyl peptidase-I/CLN2 protein which is deficient in classical late infantile neuronal ceroid lipofuscinosis.

PubMed

Ezaki, J; Takeda-Ezaki, M; Oda, K; Kominami, E

2000-02-24

Endopeptidase activities of the CLN2 gene product (Cln2p)/tripeptidyl peptidase I (TPP-I), purified from rat spleen, were studied using the synthetic fluorogenic substrates. We designed and constructed decapeptides, based on the known sequence cleavage specificities of bacterial pepstatin-insensitive carboxyl proteases (BPICP). MOCAc-Gly-Lys-Pro-Ile-Pro-Phe-Phe-Arg-Leu-Lys(Dnp)r-NH(2) is readily hydrolyzed by Cln2p/TPP-I (K(cat)/K(m) = 7.8 s(-1) mM(-1)). The enzyme had a maximal activity at pH 3.0 for an endopeptidase substrate, but at pH 4.5 with respect to tripeptidyl peptidase activity. Both endopeptidase and tripeptidyl peptidase activities were strongly inhibited by Ala-Ala-Phe-CH(2)Cl, but not inhibited by tyrostatin, an inhibitor of bacterial pepstatin-insensitive carboxyl proteases, pepstatin, or inhibitors of serine proteases. Fibroblasts from classical late infantile neuronal ceroid lipofuscinosis patients have less than 5% of the normal tripeptidyl peptidase activity and pepstatin-insensitive endopeptidase activity. Cln2p/TPP-I is a unique enzyme with both tripeptidyl peptidase and endopeptidase activities for certain substrate specificity. Copyright 2000 Academic Press.

Substance P increases sympathetic activity during combined angiotensin-converting enzyme and dipeptidyl peptidase-4 inhibition.

PubMed

Devin, Jessica K; Pretorius, Mias; Nian, Hui; Yu, Chang; Billings, Frederic T; Brown, Nancy J

2014-05-01

Dipeptidyl peptidase-4 inhibitors prevent the degradation of incretin hormones and reduce postprandial hyperglycemia in patients with type 2 diabetes mellitus. Dipeptidyl peptidase-4 degrades other peptides with a penultimate proline or alanine, including bradykinin and substance P, which are also substrates of angiotensin-converting enzyme (ACE). During ACE inhibition, substance P is inactivated primarily by dipeptidyl peptidase-4, whereas bradykinin is first inactivated by aminopeptidase P. This study tested the hypothesis that dipeptidyl peptidase-4 inhibition potentiates vasodilator and fibrinolytic responses to substance P when ACE is inhibited. Twelve healthy subjects participated in this randomized, double-blinded, placebo-controlled crossover study. On each study day, subjects received sitagliptin 200 mg by mouth or placebo. Substance P and bradykinin were infused via brachial artery before and during intra-arterial enalaprilat. Sitagliptin and enalaprilat each reduced forearm vascular resistance and increased forearm blood flow without affecting mean arterial pressure, but there was no interactive effect of the inhibitors. Enalaprilat increased bradykinin-stimulated vasodilation and tissue plasminogen activator release; sitagliptin did not affect these responses to bradykinin. The vasodilator response to substance P was unaffected by sitagliptin and enalaprilat; however, substance P increased heart rate and vascular release of norepinephrine during combined ACE and dipeptidyl peptidase-4 inhibition. In women, sitagliptin diminished tissue plasminogen activator release in response to substance P both alone and during enalaprilat. Substance P increases sympathetic activity during combined ACE and dipeptidyl peptidase-4 inhibition. - URL: http://www.clinicaltrials.gov. Unique identifier: NCT01413542.

Substance P increases Sympathetic Activity during Combined Angiotensin Converting Enzyme and Dipeptidyl Peptidase-4 Inhibition

PubMed Central

Devin, Jessica K.; Pretorius, Mias; Nian, Hui; Yu, Chang; Billings, Frederic T.; Brown, Nancy J.

2014-01-01

Dipeptidyl peptidase-4 inhibitors prevent the degradation of incretin hormones and reduce post-prandial hyperglycemia in patients with type 2 diabetes mellitus. Dipeptidyl peptidase-4 degrades other peptides with a penultimate proline or alanine, including bradykinin and substance P, which are also substrates of angiotensin-converting enzyme. During angiotensin-converting enzyme inhibition, substance P is inactivated primarily by dipeptidyl peptidase-4, while bradykinin is first inactivated by aminopeptidase P. This study tested the hypothesis that dipeptidyl peptidase-4 inhibition potentiates vasodilator and fibrinolytic responses to substance P when angiotensin-converting enzyme is inhibited. Twelve healthy subjects participated in this randomized, double-blinded, placebo-controlled crossover study. On each study day, subjects received sitagliptin 200 mg p.o. or placebo. Substance P and bradykinin were infused via brachial artery before and during intra-arterial enalaprilat. Sitagliptin and enalaprilat each reduced forearm vascular resistance and increased forearm blood flow without affecting mean arterial pressure, but there was no interactive effect of the inhibitors. Enalaprilat increased bradykinin-stimulated vasodilation and tissue plasminogen activator release; sitagliptin did not affect these responses to bradykinin. The vasodilator response to substance P was unaffected by sitagliptin and enalaprilat, however, substance P increased heart rate and vascular release of norepinephrine during combined angiotensin-converting enzyme and dipeptidyl peptidase-4 inhibition. In women, sitagliptin diminished tissue plasminogen activator release in response to substance P both alone and during enalaprilat. Substance P increases sympathetic activity during combined angiotensin-converting enzyme and dipeptidyl peptidase-4 inhibition. PMID:24516103

Teratogenic Potential of 4-Nitrophenyl Methyl Phenyl Phosphinate (MPP) in Rats.

DTIC Science & Technology

1987-10-01

Dosage of MPP (mg/kg/day) 0 3.12 1.25 0.12 No. % No. Z No. % No. % No. of fetuses examined 215 315 238 280 Anoral ies Domed cranium 1 0 Cleft palate 1...kg/day) 0 3.12 1.25 0.12 No. X No. Z No. Z No. % No. of fetuses examined 105 154 113 134 Anomalies Cleft palate 1 1 Variants Dilated brain ventricles...such as cleft palate , protruding tongue, abnormal cranium and mandible, were considered anomalies. .Minor variations in the number or degree of

Bioinformatic flowchart and database to investigate the origins and diversity of Clan AA peptidases

PubMed Central

Llorens, Carlos; Futami, Ricardo; Renaud, Gabriel; Moya, Andrés

2009-01-01

Background Clan AA of aspartic peptidases relates the family of pepsin monomers evolutionarily with all dimeric peptidases encoded by eukaryotic LTR retroelements. Recent findings describing various pools of single-domain nonviral host peptidases, in prokaryotes and eukaryotes, indicate that the diversity of clan AA is larger than previously thought. The ensuing approach to investigate this enzyme group is by studying its phylogeny. However, clan AA is a difficult case to study due to the low similarity and different rates of evolution. This work is an ongoing attempt to investigate the different clan AA families to understand the cause of their diversity. Results In this paper, we describe in-progress database and bioinformatic flowchart designed to characterize the clan AA protein domain based on all possible protein families through ancestral reconstructions, sequence logos, and hidden markov models (HMMs). The flowchart includes the characterization of a major consensus sequence based on 6 amino acid patterns with correspondence with Andreeva's model, the structural template describing the clan AA peptidase fold. The set of tools is work in progress we have organized in a database within the GyDB project, referred to as Clan AA Reference Database . Conclusion The pre-existing classification combined with the evolutionary history of LTR retroelements permits a consistent taxonomical collection of sequence logos and HMMs. This set is useful for gene annotation but also a reference to evaluate the diversity of, and the relationships among, the different families. Comparisons among HMMs suggest a common ancestor for all dimeric clan AA peptidases that is halfway between single-domain nonviral peptidases and those coded by Ty3/Gypsy LTR retroelements. Sequence logos reveal how all clan AA families follow similar protein domain architecture related to the peptidase fold. In particular, each family nucleates a particular consensus motif in the sequence position related to the flap. The different motifs constitute a network where an alanine-asparagine-like variable motif predominates, instead of the canonical flap of the HIV-1 peptidase and closer relatives. Reviewers This article was reviewed by Daniel H. Haft, Vladimir Kapitonov (nominated by Jerry Jurka), and Ben M. Dunn (nominated by Claus Wilke). PMID:19173708

Kinetic study of the processing by dipeptidyl-peptidase IV/CD26 of neuropeptides involved in pancreatic insulin secretion.

PubMed

Lambeir, A M; Durinx, C; Proost, P; Van Damme, J; Scharpé, S; De Meester, I

2001-11-02

Dipeptidyl-peptidase IV (DPPIV/CD26) metabolizes neuropeptides regulating insulin secretion. We studied the in vitro steady-state kinetics of DPPIV/CD26-mediated truncation of vasoactive intestinal peptide (VIP), pituitary adenylyl cyclase-activating peptide (PACAP27 and PACAP38), gastrin-releasing peptide (GRP) and neuropeptide Y (NPY). DPPIV/CD26 sequentially cleaves off two dipeptides of VIP, PACAP27, PACAP38 and GRP. GRP situates between the best DPPIV/CD26 substrates reported, comparable to NPY. Surprisingly, the C-terminal extension of PACAP38, distant from the scissile bond, improves both PACAP38 binding and turnover. Therefore, residues remote from the scissile bond can modulate DPPIV/CD26 substrate selectivity as well as residues flanking it.

[Changes in proline-specific peptidase activity in experimental model of retrograde amnesia].

PubMed

Nazarova, G A; Zolotov, N N; Krupina, N A; Kraĭneva, V A; Garibova, T L; Voronina, T A

2007-01-01

Changes in proline-specific peptidase activity in the frontal cortex and hippocampus were studied using the experimental model of retrograde amnesia in rats. In one group, the amnesia was produced by a single injection of M-cholinergic antagonist scopolamine and the other group received the maximal electroconvulsive stimulation (MES). The amnesic effect was evaluated in passive avoidance test. In the amnesia models under consideration, the activity of prolylendopeptidase was significantly increased in both frontal cortex and hippocampus. The activity of dipeptidyl peptidase IV was significantly decreased in the cortex, whereas in the hippocampus it remained unchanged. Pyracetam inhibited prolylendopeptidase in the cortex and hippocampus, whereas dipeptidyl peptidase IV activity remained unchanged.

Evidence for an Angiotensin-(1–7) Neuropeptidase Expressed in the Brain Medulla and CSF of Sheep

PubMed Central

Marshall, Allyson C.; Pirro, Nancy T.; Rose, James C.; Diz, Debra I.; Chappell, Mark C.

2014-01-01

Angiotensin-(1–7) [Ang-(1–7)] is an alternative product of the brain renin-angiotensin system (RAS) that exhibits central actions to lower blood pressure and improve baroreflex sensitivity. We previously identified a peptidase that metabolizes Ang-(1–7) to the inactive metabolite product Ang-(1–4) in CSF of adult sheep. The current study purified the peptidase 1445-fold from sheep brain medulla and characterized this activity. The peptidase was sensitive to the chelating agents o-phenanthroline and EDTA, as well as the mercury compound p-chloromercuribenzoic acid (PCMB). Selective inhibitors to angiotensin-converting enzyme, neprilysin, neurolysin, and thimet oligopeptidase did not attenuate activity; however, the metallopeptidase agent JMV-390 was a potent inhibitor of Ang-(1–7) hydrolysis (Ki = 0.8 nM). Kinetic studies using 125I-labeled Ang-(1–7), Ang II, and Ang I revealed comparable apparent Km values (2.6, 2.8 and 4.3 µM, respectively), but a higher apparent Vmax for Ang-(1–7) (72 vs. 30 and 6 nmol/min/mg, respectively; P<0.01). HPLC analysis of the activity confirmed the processing of unlabeled Ang-(1–7) to Ang-(1–4) by the peptidase, but revealed <5% hydrolysis of Ang II or Ang I, and no hydrolysis of neurotensin, bradykinin or apelin-13. The unique characteristics of the purified neuropeptidase may portend a novel pathway to influence actions of Ang-(1–7) within the brain. PMID:24661079

Muenster Parental Programme empowers parents in communicating with their infant with hearing loss.

PubMed

Glanemann, Reinhild; Reichmuth, Karen; Matulat, Peter; Zehnhoff-Dinnesen, Antoinette Am

2013-12-01

With the implementation of the Universal Newborn Hearing Screening (UNHS), the age of diagnosis of children with hearing loss (HL) has been steadily declining in the past years. Consequently, there is a need for early educational intervention methods that are suitable for infants at the preverbal level. To meet this need we have developed and evaluated the Muenster Parental Programme (MPP), a responsive parenting programme for parents of children with HL aged 3-18 months. It aims at enhancing the parents' communicative skills towards their child. The MPP is introduced following confirmation of a HL. Flanked by two individual counselling sessions, the programme comprises six group sessions and two single training sessions with video feedback. The focus of the programme lies in enhancing parents' responsive behaviour and in reducing inappropriate initiative behaviour. The present study involved 29 parents of 24 children aged 6.6 (mean, range: 3-12) months at the outset of the MPP. The children's degree of HL ranged from moderate to profound. Parents of children with unilateral HL and/or risk for an additional developmental delay were included. The prospective study compared parent communication skills of a trained (N = 15) versus a control group (N = 14) before and after the MPP. For this purpose, instances of responsive behaviour to the signals of the child and total time of initiative behaviour within a 4-min video-sample were measured before and after completion of the study in both groups. Trained parents could enhance their responsiveness to vocal and preverbal signals of the child (Wilcoxon test, p = .002) and also their responsiveness to non-verbal signals (Wilcoxon test, p < .001). Moreover, parents reduced their inappropriate initiative behaviour (related t-test, p < .001). Pre-post comparisons in the control group were non-significant. The increased parental responsiveness to infants with HL is of great importance as these early behaviours underlie later acquisition of speech, language, hearing and social communication skills. The MPP constitutes the first evaluated group concept for parents of infants with HL in the German-speaking countries and equally meets the needs of parents and professionals. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Mechanism of Peptide Binding and Cleavage by the Human Mitochondrial Peptidase Neurolysin.

PubMed

Teixeira, Pedro F; Masuyer, Geoffrey; Pinho, Catarina M; Branca, Rui M M; Kmiec, Beata; Wallin, Cecilia; Wärmländer, Sebastian K T S; Berntsson, Ronnie P-A; Ankarcrona, Maria; Gräslund, Astrid; Lehtiö, Janne; Stenmark, Pål; Glaser, Elzbieta

2018-02-02

Proteolysis plays an important role in mitochondrial biogenesis, from the processing of newly imported precursor proteins to the degradation of mitochondrial targeting peptides. Disruption of peptide degradation activity in yeast, plant and mammalian mitochondria is known to have deleterious consequences for organism physiology, highlighting the important role of mitochondrial peptidases. In the present work, we show that the human mitochondrial peptidase neurolysin (hNLN) can degrade mitochondrial presequence peptides as well as other fragments up to 19 amino acids long. The crystal structure of hNLN E475Q in complex with the products of neurotensin cleavage at 2.7Å revealed a closed conformation with an internal cavity that restricts substrate length and highlighted the mechanism of enzyme opening/closing that is necessary for substrate binding and catalytic activity. Analysis of peptide degradation in vitro showed that hNLN cooperates with presequence protease (PreP or PITRM1) in the degradation of long targeting peptides and amyloid-β peptide, Aβ1-40, associated with Alzheimer disease, particularly cleaving the hydrophobic fragment Aβ35-40. These findings suggest that a network of proteases may be required for complete degradation of peptides localized in mitochondria. Copyright © 2017 Elsevier Ltd. All rights reserved.

The MAPK Signaling Cascade is a Central Hub in the Regulation of Cell Cycle, Apoptosis and Cytoskeleton Remodeling by Tripeptidyl-Peptidase II

PubMed Central

Sompallae, Ramakrishna; Stavropoulou, Vaia; Houde, Mathieu; Masucci, Maria G.

2008-01-01

Tripeptidyl-peptidase II (TPPII) is a serine peptidase highly expressed in malignant Burkitt’s lymphoma cells (BL). We have previously shown that overexpression of TPPII correlates with chromosomal instability, centrosomal and mitotic spindle abnormalities and resistance to apoptosis induced by spindle poisons. Furthermore, TPPII knockdown by RNAi was associated with endoreplication and the accumulation of polynucleated cells that failed to complete cell division, indicating a role of TPPII in the cell cycle. Here we have applied a global approach of gene expression analysis to gain insights on the mechanism by which TPPII regulates this phenotype. mRNA profiling of control and TPPII knockdown BL cells identified one hundred and eighty five differentially expressed genes. Functional categorization of these genes highlighted major physiological functions such as apoptosis, cell cycle progression, cytoskeleton remodeling, proteolysis, and signal transduction. Pathways and protein interactome analysis revealed a significant enrichment in components of MAP kinases signaling. These findings suggest that TPPII influences a wide network of signaling pathways that are regulated by MAPKs and exerts thereby a pleiotropic effect on biological processes associated with cell survival, proliferation and genomic instability. PMID:19787088

Degradation Paradigm of the Gut Hormone, Pancreatic Polypeptide, by Hepatic and Renal Peptidases

PubMed Central

Minnion, James; Tan, Tricia; Scott, Rebecca; Germain, Natacha; Ling, Yiin; Chen, Rong; Ghatei, Mohammad; Bloom, Stephen

2017-01-01

Pancreatic polypeptide (PP) is a gut hormone that acts on Y4 receptors to reduce appetite. Obese humans display a reduced postprandial increase in PP and remain fully sensitive to the anorectic effects of exogenous PP. The utility of PP as an anti-obesity treatment is limited by its short circulating half-life. Insight into the mechanisms by which PP is degraded could aid in the design of long-acting PP analogs. We investigated the role of peptidases in PP degradation to determine whether inhibition of these enzymes enhanced PP plasma levels and bioactivity in vivo. Dipeptidyl peptidase IV (DPPIV) and neprilysin (NEP) were two peptidase found to cleave PP. Limiting the effect of both peptidases improved the in vivo anorectic effect of PP and PP-based analogs. These findings suggest that inhibiting the degradation of PP using specific inhibitors and/or the design of analogs resistant to cleavage by DPPIV and NEP might be useful in the development of PP as an anti-obesity pharmacotherapy. PMID:28323997

The PPARgamma agonist pioglitazone is effective in the MPTP mouse model of Parkinson's disease through inhibition of monoamine oxidase B.

PubMed

Quinn, L P; Crook, B; Hows, M E; Vidgeon-Hart, M; Chapman, H; Upton, N; Medhurst, A D; Virley, D J

2008-05-01

The peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist pioglitazone has previously been shown to attenuate dopaminergic cell loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease, an effect attributed to its anti-inflammatory properties. In the present investigation, we provide evidence that pioglitazone is effective in the MPTP mouse model, not via an anti-inflammatory action, but through inhibition of MAO-B, the enzyme required to biotransform MPTP to its active neurotoxic metabolite 1-methyl-4-phenylpyridinium (MPP+). Mice were treated with pioglitazone (20 mg kg(-1) b.i.d. (twice a day), p.o., for 7 days), prior and post or post-MPTP (30 mg kg(-1) s.c.) treatment. Mice were then assessed for motor impairments on a beam-walking apparatus and for reductions in TH immunoreactivity in the substantia nigra and depletions in striatal dopamine. The effects of pioglitazone on striatal MPP+ levels and MAO-B activity were also assessed. Mice treated with MPTP showed deficits in motor performance, marked depletions in striatal dopamine levels and a concomitant reduction in TH immunoreactivity in the substantia nigra. Pretreatment with pioglitazone completely prevented these effects of MPTP. However, pretreatment with pioglitazone also significantly inhibited the MPTP-induced production of striatal MPP+ and the activity of MAO-B in the striatum. The neuroprotection observed with pioglitazone pretreatment in the MPTP mouse model was due to the blockade of the conversion of MPTP to its active toxic metabolite MPP+, via inhibition of MAO-B.

Distinct Effects of Rotenone, 1-methyl-4-phenylpyridinium and 6-hydroxydopamine on Cellular Bioenergetics and Cell Death

PubMed Central

Giordano, Samantha; Lee, Jisun; Darley-Usmar, Victor M.; Zhang, Jianhua

2012-01-01

Parkinson’s disease is characterized by dopaminergic neurodegeneration and is associated with mitochondrial dysfunction. The bioenergetic susceptibility of dopaminergic neurons to toxins which induce Parkinson’s like syndromes in animal models is then of particular interest. For example, rotenone, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its active metabolite 1-methyl-4-phenylpyridinium (MPP+), and 6-hydroxydopamine (6-OHDA), have been shown to induce dopaminergic cell death in vivo and in vitro. Exposure of animals to these compounds induce a range of responses characteristics of Parkinson’s disease, including dopaminergic cell death, and Reactive Oxygen Species (ROS) production. Here we test the hypothesis that cellular bioenergetic dysfunction caused by these compounds correlates with induction of cell death in differentiated dopaminergic neuroblastoma SH-SY5Y cells. At increasing doses, rotenone induced significant cell death accompanied with caspase 3 activation. At these concentrations, rotenone had an immediate inhibition of mitochondrial basal oxygen consumption rate (OCR) concomitant with a decrease of ATP-linked OCR and reserve capacity, as well as a stimulation of glycolysis. MPP+ exhibited a different behavior with less pronounced cell death at doses that nearly eliminated basal and ATP-linked OCR. Interestingly, MPP+, unlike rotenone, stimulated bioenergetic reserve capacity. The effects of 6-OHDA on bioenergetic function was markedly less than the effects of rotenone or MPP+ at cytotoxic doses, suggesting a mechanism largely independent of bioenergetic dysfunction. These studies suggest that these dopaminergic neurotoxins induce cell death through distinct mechanisms and differential effects on cellular bioenergetics. PMID:22970265

Effect of altered arterial perfusion pressure on vascular conductance and muscle blood flow dynamic response during exercise in humans.

PubMed

Villar, Rodrigo; Hughson, Richard L

2013-03-01

Changes in vascular conductance (VC) are required to counter changes in muscle perfusion pressure (MPP) to maintain muscle blood flow (MBF) during exercise. We investigated the recruitment of VC as a function of peak VC measured in three body positions at two different work rates to test the hypothesis that adaptations in VC compensated changes in MPP at low-power output (LPO), but not at high-power output (HPO). Eleven healthy volunteers exercised at LPO and HPO (repeated plantar flexion contractions at 20-30% maximal voluntary contraction, respectively) in horizontal (HOR), 35° head-down tilt (HDT), and 45° head-up tilt (HUT). Muscle blood flow velocity and popliteal diameter were measured by ultrasound to determine MBF, and VC was estimated by dividing MBF flow by MPP. Peak VC was unaffected by body position. The rates of increase in MBF and VC were significantly faster in HUT and slower in HDT than HOR, and rates were faster in LPO than HPO. During LPO exercise, the increase in, and steady-state values of, MBF were less for HUT and HDT than HOR; the increase in VC was less in HUT than HOR and HDT. During HPO exercise, MBF in the HDT was reduced compared with HOR and HUT, even though VC reached 92% VC peak, which was greater than HOR, which was, in turn, greater than HUT. Reduced MBF during HPO HDT exercise had the functional consequence of a significant increase in muscle electromyographic index, revealing the effects of MPP on O2 delivery during exercise.

Inhibition of DD-Peptidases by a Specific Trifluoroketone: Crystal Structure of a Complex with the Actinomadura R39 DD-Peptidase†

PubMed Central

Dzhekieva, Liudmila; Adediran, S. A.; Herman, Raphael; Kerff, Frédéric; Duez, Colette; Charlier, Paulette; Sauvage, Eric; Pratt, R.F.

2013-01-01

Inhibitors of bacterial DD-peptidases represent potential antibiotics. In the search for alternatives to β-lactams, we have investigated a series of compounds designed to generate transition state analogue structures on reaction with DD-peptidases. The compounds contain a combination of a peptidoglycan-mimetic specificity handle and a warhead capable of delivering a tetrahedral anion to the enzyme active site. The latter include a boronic acid, two alcohols, an aldehyde and a trifluoroketone. The compounds were tested against two low molecular mass class C DD-peptidases. As expected from previous observations, the boronic acid was a potent inhibitor, but, rather unexpectedly from precedent, the trifluoroketone [D-α-aminopimelyl-(1,1,1-trifluoro-3-amino)butan-2-one] was also very effective. Taking into account competing hydration, the trifluoroketone was the strongest inhibitor of the Actinomadura R39 DD-peptidase, with a subnanomolar (free ketone) inhibition constant. A crystal structure of the complex between the trifluoroketone and the R39 enzyme showed that a tetrahedral adduct had indeed formed with the active site serine nucleophile. The trifluoroketone moiety, therefore, should be considered along with boronic acids and phosphonates, as a warhead that can be incorporated into new and effective DD-peptidase inhibitors and therefore, perhaps, antibiotics. PMID:23484909

The identification and biochemical properties of the catalytic specificity of a serine peptidase secreted by Aspergillus fumigatus Fresenius.

PubMed

da Silva, Ronivaldo Rodrigues; Caetano, Renato Cesar; Okamoto, Debora Nona; de Oliveira, Lilian Caroline Goncalves; Bertolin, Thiago Carlos; Juliano, Maria Aparecida; Juliano, Luiz; de Oliveira, Arthur H C; Rosae, Jose C; Cabral, Hamilton

2014-07-01

Aspergillus fumigatus is a saprophytic fungus as well as a so-called opportunist pathogen. Its biochemical potential and enzyme production justify intensive studies about biomolecules secreted by this microorganism. We describe the alkaline serine peptidase production, with optimum activity at 50°C and a pH of 7.5 and a reduction in proteolytic activity in the presence of the Al(+3) ions. When using intramolecularly quenched fluorogenic substrates, the highest catalytic efficiency was observed with the amino acid leucine on subsite S'(3) (60,000 mM(-1)s(-1)) and preference to non-polar amino acids on subsite S(3). In general, however, the peptidase shows non-specificity on other subsites studied. According to the biochemical characteristics, this peptidase may be an important biocatalyst for the hydrolysis of an enormous variety of proteins and can constitute an essential molecule for the saprophytic lifestyle or invasive action of the opportunistic pathogen. The peptidase described herein exhibits an estimated molecular mass of 33 kDa. Mass spectrometry analysis identified the sequence GAPWGLGSISHK displaying similarities to that of serine peptidase from Aspergillus fumigatus. These data may lead to a greater understanding of the advantageous biochemical potential, biotechnological interest, and trends of this fungus in spite of being an opportunist pathogen.

Catabolism of gastrin releasing peptide and substance P by gastric membrane-bound peptidases.

PubMed

Bunnett, N W; Kobayashi, R; Orloff, M S; Reeve, J R; Turner, A J; Walsh, J H

1985-01-01

The catabolism of two gastric neuropeptides, the C-terminal decapeptide of gastrin releasing peptide-27 (GRP10) and substance P (SP), by membrane-bound peptidases of the porcine gastric corpus and by porcine endopeptidase-24.11 ("enkephalinase") has been investigated. GRP10 was catabolized by gastric muscle peptidases (specific activity 1.8 nmol min-1 mg-1 protein) by hydrolysis of the His8-Leu9 bond and catabolism was inhibited by phosphoramidon (I50 approx. 10(-8) M), a specific inhibitor of endopeptidase-24.11. The same bond in GRP10 was cleaved by purified endopeptidase-24.11, and hydrolysis was equally sensitive to inhibition by phosphoramidon. SP was catabolized by gastric muscle peptidases (specific activity 1.7 nmol min-1 mg-1 protein) by hydrolysis of the Gln6-Phe7, Phe7-Phe8 and Gly9-Leu10 bonds, which is identical to the cleavage of SP by purified endopeptidase-24.11. The C-terminal cleavage of GRP10 and SP would inactivate the peptides. It is concluded that a membrane-bound peptidase in the stomach wall catabolizes and inactivates GRP10 and SP and that, in its specificity and sensitivity to phosphoramidon, this peptidase resembles endopeptidase-24.11.

Comparing analgesia and μ-opioid receptor internalization produced by intrathecal enkephalin

PubMed Central

Chen, Wenling; Song, Bingbing; Lao, Lijun; Pérez, Orlando A.; Kim, Woojae; Marvizón, Juan Carlos G.

2007-01-01

Summary Opioid receptors in the spinal cord produce strong analgesia, but the mechanisms controlling their activation by endogenous opioids remain unclear. We have previously shown in spinal cord slices that peptidases preclude μ-opioid receptor (MOR) internalization by opioids. Our present goals were to investigate whether enkephalin-induced analgesia is also precluded by peptidases, and whether it is mediated by MORs or δ-opioid receptors (DORs). Tail-flick analgesia and MOR internalization were measured in rats injected intrathecally with Leu-enkephalin and peptidase inhibitors. Without peptidase inhibitors, Leu-enkephalin produced neither analgesia nor MOR internalization at doses up to 100 nmol, whereas with peptidase inhibitors it produced analgesia at 0.3 nmol and MOR internalization at 1 nmol. Leu-enkephalin was ten times more potent to produce analgesia than to produce MOR internalization, suggesting that DORs were involved. Selective MOR or DOR antagonists completely blocked the analgesia elicited by 0.3 nmol Leu-enkephalin (a dose that produced little MOR internalization), indicating that it involved these two receptors, possibly by an additive or synergistic interaction. The selective MOR agonist endomorphin-2 produced analgesia even in the presence of a DOR antagonist, but at doses substantially higher than Leu-enkephalin. Unlike Leu-enkephalin, endomorphin-2 had the same potencies to induce analgesia and MOR internalization. We concluded that low doses of enkephalins produce analgesia by activating both MORs and DORs. Analgesia can also be produced exclusively by MORs at higher agonist doses. Since peptidases prevent the activation of spinal opioid receptors by enkephalins, the coincident release of opioids and endogenous peptidase inhibitors may be required for analgesia. PMID:17845806

Dipeptidyl peptidase IV in angiotensin-converting enzyme inhibitor associated angioedema.

PubMed

Byrd, James Brian; Touzin, Karine; Sile, Saba; Gainer, James V; Yu, Chang; Nadeau, John; Adam, Albert; Brown, Nancy J

2008-01-01

Angioedema is a potentially life-threatening adverse effect of angiotensin-converting enzyme inhibitors. Bradykinin and substance P, substrates of angiotensin-converting enzyme, increase vascular permeability and cause tissue edema in animals. Studies indicate that amino-terminal degradation of these peptides, by aminopeptidase P and dipeptidyl peptidase IV, may be impaired in individuals with angiotensin-converting enzyme inhibitor-associated angioedema. This case-control study tested the hypothesis that dipeptidyl peptidase IV activity and antigen are decreased in sera of patients with a history of angiotensin-converting enzyme inhibitor-associated angioedema. Fifty subjects with a history of angiotensin-converting enzyme inhibitor-associated angioedema and 176 angiotensin-converting enzyme inhibitor-exposed control subjects were ascertained. Sera were assayed for angiotensin-converting enzyme activity, aminopeptidase P activity, aminopeptidase N activity, dipeptidyl peptidase IV activity, and antigen and the ex vivo degradation half-lives of bradykinin, des-Arg(9)-bradykinin, and substance P in a subset. The prevalence of smoking was increased and of diabetes decreased in case versus control subjects. Overall, dipeptidyl peptidase IV activity (26.6+/-7.8 versus 29.6+/-7.3 nmol/mL per minute; P=0.026) and antigen (465.8+/-260.8 versus 563.1+/-208.6 ng/mL; P=0.017) were decreased in sera from individuals with angiotensin-converting enzyme inhibitor-associated angioedema compared with angiotensin-converting enzyme inhibitor-exposed control subjects without angioedema. Dipeptidyl peptidase IV activity (21.5+/-4.9 versus 29.8+/-6.7 nmol/mL per minute; P=0.001) and antigen (354.4+/-124.7 versus 559.8+/-163.2 ng/mL; P=0.003) were decreased in sera from cases collected during angiotensin-converting enzyme inhibition but not in the absence of angiotensin-converting enzyme inhibition. The degradation half-life of substance P correlated inversely with dipeptidyl peptidase IV antigen during angiotensin-converting enzyme inhibition. Environmental or genetic factors that reduce dipeptidyl peptidase IV activity may predispose individuals to angioedema.

Dipeptidyl Peptidase IV in Angiotensin-Converting Enzyme Inhibitor–Associated Angioedema

PubMed Central

Byrd, James Brian; Touzin, Karine; Sile, Saba; Gainer, James V.; Yu, Chang; Nadeau, John; Adam, Albert; Brown, Nancy J.

2009-01-01

Angioedema is a potentially life-threatening adverse effect of angiotensin-converting enzyme inhibitors. Bradykinin and substance P, substrates of angiotensin-converting enzyme, increase vascular permeability and cause tissue edema in animals. Studies indicate that amino-terminal degradation of these peptides, by aminopeptidase P and dipeptidyl peptidase IV, may be impaired in individuals with angiotensin-converting enzyme inhibitor–associated angioedema. This case-control study tested the hypothesis that dipeptidyl peptidase IV activity and antigen are decreased in sera of patients with a history of angiotensin-converting enzyme inhibitor–associated angioedema. Fifty subjects with a history of angiotensin-converting enzyme inhibitor–associated angioedema and 176 angiotensin-converting enzyme inhibitor–exposed control subjects were ascertained. Sera were assayed for angiotensin-converting enzyme activity, aminopeptidase P activity, aminopeptidase N activity, dipeptidyl peptidase IV activity, and antigen and the ex vivo degradation half-lives of bradykinin, des-Arg9-bradykinin, and substance P in a subset. The prevalence of smoking was increased and of diabetes decreased in case versus control subjects. Overall, dipeptidyl peptidase IV activity (26.6±7.8 versus 29.6±7.3 nmol/mL per minute; P=0.026) and antigen (465.8±260.8 versus 563.1±208.6 ng/mL; P=0.017) were decreased in sera from individuals with angiotensin-converting enzyme inhibitor–associated angioedema compared with angiotensin-converting enzyme inhibitor–exposed control subjects without angioedema. Dipeptidyl peptidase IV activity (21.5±4.9 versus 29.8±6.7 nmol/mL per minute; P=0.001) and antigen (354.4±124.7 versus 559.8±163.2 ng/mL; P=0.003) were decreased in sera from cases collected during angiotensin-converting enzyme inhibition but not in the absence of angiotensin-converting enzyme inhibition. The degradation half-life of substance P correlated inversely with dipeptidyl peptidase IV antigen during angiotensin-converting enzyme inhibition. Environmental or genetic factors that reduce dipeptidyl peptidase IV activity may predispose individuals to angioedema. PMID:18025295

1,10-phenanthroline inhibits the metallopeptidase secreted by Phialophora verrucosa and modulates its growth, morphology and differentiation.

PubMed

Granato, Marcela Queiroz; Massapust, Priscila de Araújo; Rozental, Sonia; Alviano, Celuta Sales; dos Santos, André Luis Souza; Kneipp, Lucimar Ferreira

2015-04-01

Phialophora verrucosa is one of the etiologic agents of chromoblastomycosis, a fungal infection that affects cutaneous and subcutaneous tissues. This disease is chronic, recurrent and difficult to treat. Several studies have shown that secreted peptidases by fungi are associated with important pathophysiological processes. Herein, we have identified and partially characterized the peptidase activity secreted by P. verrucosa conidial cells. Using human serum albumin as substrate, the best hydrolysis profile was detected at extreme acidic pH (3.0) and at 37 °C. The enzymatic activity was completely blocked by classical metallopeptidase inhibitors/chelating agents as 1,10-phenanthroline and EGTA. Zinc ions stimulated the metallo-type peptidase activity in a dose-dependent manner. Several proteinaceous substrates were cleaved, in different extension, by the P. verrucosa metallopeptidase activity, including immunoglobulin G, fibrinogen, collagen types I and IV, fibronectin, laminin and keratin; however, mucin and hemoglobin were not susceptible to proteolysis. As metallopeptidases participate in different cellular metabolic pathways in fungal cells, we also tested the influence of 1,10-phenanthroline and EGTA on P. verrucosa development. Contrarily to EGTA, 1,10-phenanthroline inhibited the fungal viability (MIC 0.8 µg/ml), showing fungistatic effect, and induced profound morphological alterations as visualized by transmission electron microscopy. In addition, 1,10-phenanthroline arrested the filamentation process in P. verrucosa. Our results corroborate the supposition that metallopeptidase inhibitors/chelating agents have potential to control crucial biological events in fungal agents of chromoblastomycosis.

Improving maximum power point tracking of partially shaded photovoltaic system by using IPSO-BELBIC

NASA Astrophysics Data System (ADS)

Al-Alim El-Garhy, M. Abd; Mubarak, R. I.; El-Bably, M.

2017-08-01

Solar photovoltaic (PV) arrays in remote applications are often related to the rapid changes in the partial shading pattern. Rapid changes of the partial shading pattern make the tracking of maximum power point (MPP) of the global peak through the local ones too difficult. An essential need to make a fast and efficient algorithm to detect the peaks values which always vary as the sun irradiance changes. This paper presents two algorithms based on the improved particle swarm optimization technique one of them with PID controller (IPSO-PID), and the other one with Brain Emotional Learning Based Intelligent Controller (IPSO-BELBIC). These techniques improve the maximum power point (MPP) tracking capabilities for photovoltaic (PV) system under partial shading circumstances. The main aim of these improved algorithms is to accelerate the velocity of IPSO to reach to (MPP) and increase its efficiency. These algorithms also improve the tracking time under complex irradiance conditions. Based on these conditions, the tracking time of these presented techniques improves to 2 msec, with an efficiency of 100%.

Acetaminophen and aspirin inhibit superoxide anion generation and lipid peroxidation, and protect against 1-methyl-4-phenyl pyridinium-induced dopaminergic neurotoxicity in rats.

PubMed

Maharaj, D S; Saravanan, K S; Maharaj, H; Mohanakumar, K P; Daya, S

2004-04-01

We assessed the antioxidant activity of non-narcotic analgesics, acetaminophen and aspirin in rat brain homogenates and neuroprotective effects in vivo in rats intranigrally treated with 1-methyl-4-phenyl pyridinium (MPP+). Both drugs inhibited cyanide-induced superoxide anion generation, as well as lipid peroxidation in rat brain homogenates, the combination of the agents resulting in a potentiation of this effect. Acetaminophen or aspirin when administered alone or in combination, did not alter dopamine (DA) levels in the forebrain or in the striatum. Intranigral infusion of MPP+ in rats caused severe depletion of striatal DA levels in the ipsilateral striatum in rats by the third day. Systemic post-treatment of acetaminophen afforded partial protection, whereas similar treatment of aspirin resulted in complete blockade of MPP+-induced striatal DA depletion. While these findings suggest usefulness of non-narcotic analgesics in neuroprotective therapy in neurodegenerative diseases, aspirin appears to be a potential candidate in prophylactic as well as in adjuvant therapy in Parkinson's disease.

Biostable beta-Amino Acid PK/PBAN Analogs: Agonist and Antagonist Properties

DTIC Science & Technology

2009-01-01

peptidases neprilysin and angiotensin converting enzyme that are shown to degrade the natural peptides . Despite the changes to the PK core, analog PK-bA-4...bound peptidase - resistant analogs of the insect allatostatins. Peptides 1999;20:23–9. [21] Nachman RJ, Holman GM, Cook BJ. Active fragments and...pheromonotropic activity of peptidase -resistant topical amphiphilic analogs of pyrokinin/PBAN insect neuropeptides. Peptides 2002;23:2035–43. [28] Nachman RJ

The degradation of bioactive peptides and proteins by dipeptidyl peptidase IV from human placenta.

PubMed

Nausch, I; Mentlein, R; Heymann, E

1990-11-01

The degradation of several bioactive peptides and proteins by purified human dipeptidyl peptidase IV is reported. It was hitherto unknown that human gastrin-releasing peptide, human chorionic gonadotropin, human pancreatic polypeptide, sheep prolactin, aprotinin, corticotropin-like intermediate lobe peptide and (Tyr-)melanostatin are substrates of this peptidase. Kinetic constants were determined for the degradation of a number of other natural peptides, including substance P, the degradation of which has been described earlier in a qualitative manner. Generally, small peptides are degraded much more rapidly than proteins. However, the Km-values seem to be independent of the peptide chain length. The influence of the action of dipeptidyl peptidase IV on the biological function of peptides and proteins is discussed.

Applications of massively parallel computers in telemetry processing

NASA Technical Reports Server (NTRS)

El-Ghazawi, Tarek A.; Pritchard, Jim; Knoble, Gordon

1994-01-01

Telemetry processing refers to the reconstruction of full resolution raw instrumentation data with artifacts, of space and ground recording and transmission, removed. Being the first processing phase of satellite data, this process is also referred to as level-zero processing. This study is aimed at investigating the use of massively parallel computing technology in providing level-zero processing to spaceflights that adhere to the recommendations of the Consultative Committee on Space Data Systems (CCSDS). The workload characteristics, of level-zero processing, are used to identify processing requirements in high-performance computing systems. An example of level-zero functions on a SIMD MPP, such as the MasPar, is discussed. The requirements in this paper are based in part on the Earth Observing System (EOS) Data and Operation System (EDOS).

Applications of Parallel Process HiMAP for Large Scale Multidisciplinary Problems

NASA Technical Reports Server (NTRS)

Guruswamy, Guru P.; Potsdam, Mark; Rodriguez, David; Kwak, Dochay (Technical Monitor)

2000-01-01

HiMAP is a three level parallel middleware that can be interfaced to a large scale global design environment for code independent, multidisciplinary analysis using high fidelity equations. Aerospace technology needs are rapidly changing. Computational tools compatible with the requirements of national programs such as space transportation are needed. Conventional computation tools are inadequate for modern aerospace design needs. Advanced, modular computational tools are needed, such as those that incorporate the technology of massively parallel processors (MPP).

Reconstruction of coded aperture images

NASA Technical Reports Server (NTRS)

Bielefeld, Michael J.; Yin, Lo I.

1987-01-01

Balanced correlation method and the Maximum Entropy Method (MEM) were implemented to reconstruct a laboratory X-ray source as imaged by a Uniformly Redundant Array (URA) system. Although the MEM method has advantages over the balanced correlation method, it is computationally time consuming because of the iterative nature of its solution. Massively Parallel Processing, with its parallel array structure is ideally suited for such computations. These preliminary results indicate that it is possible to use the MEM method in future coded-aperture experiments with the help of the MPP.

Experience in highly parallel processing using DAP

NASA Technical Reports Server (NTRS)

Parkinson, D.

1987-01-01

Distributed Array Processors (DAP) have been in day to day use for ten years and a large amount of user experience has been gained. The profile of user applications is similar to that of the Massively Parallel Processor (MPP) working group. Experience has shown that contrary to expectations, highly parallel systems provide excellent performance on so-called dirty problems such as the physics part of meteorological codes. The reasons for this observation are discussed. The arguments against replacing bit processors with floating point processors are also discussed.

Dipeptidyl peptidase-4: A key player in chronic liver disease

PubMed Central

Itou, Minoru; Kawaguchi, Takumi; Taniguchi, Eitaro; Sata, Michio

2013-01-01

Dipeptidyl peptidase-4 (DPP-4) is a membrane-associated peptidase, also known as CD26. DPP-4 has widespread organ distribution throughout the body and exerts pleiotropic effects via its peptidase activity. A representative target peptide is glucagon-like peptide-1, and inactivation of glucagon-like peptide-1 results in the development of glucose intolerance/diabetes mellitus and hepatic steatosis. In addition to its peptidase activity, DPP-4 is known to be associated with immune stimulation, binding to and degradation of extracellular matrix, resistance to anti-cancer agents, and lipid accumulation. The liver expresses DPP-4 to a high degree, and recent accumulating data suggest that DPP-4 is involved in the development of various chronic liver diseases such as hepatitis C virus infection, non-alcoholic fatty liver disease, and hepatocellular carcinoma. Furthermore, DPP-4 occurs in hepatic stem cells and plays a crucial role in hepatic regeneration. In this review, we described the tissue distribution and various biological effects of DPP-4. Then, we discussed the impact of DPP-4 in chronic liver disease and the possible therapeutic effects of a DPP-4 inhibitor. PMID:23613622

Degradation and Stabilization of Peptide Hormones in Human Blood Specimens

PubMed Central

Yi, Jizu; Warunek, David; Craft, David

2015-01-01

Plasma hormone peptides, including GLP-1, GIP, Glucagon, and OXM, possess multiple physiological roles and potential therapeutic and diagnostic utility as biomarkers in the research of metabolic disorders. These peptides are subject to proteolytic degradation causing preanalytical variations. Stabilization for accurate quantitation of these active peptides in ex vivo blood specimens is essential for drug and biomarker development. We investigated the protease-driven instability of these peptides in conventional serum, plasma, anticoagulated whole blood, as well as whole blood and plasma stabilized with protease inhibitors. The peptide was monitored by both time-course Matrix-Assisted Laser Desorption Ionization Time-to-Flight Mass Spectrometry (MALDI –TOF MS) and Ab-based assay (ELISA or RIA). MS enabled the identification of proteolytic fragments. In non-stabilized blood samples, the results clearly indicated that dipeptidyl peptidase-IV (DPP-IV) removed the N-terminal two amino acid residues from GLP-1, GIP and OXM(1-37) and not-yet identified peptidase(s) cleave(s) the full-length OXM(1-37) and its fragments. DPP-IV also continued to remove two additional N-terminal residues of processed OXM(3–37) to yield OXM(5–37). Importantly, both DPP-IV and other peptidase(s) activities were inhibited efficiently by the protease inhibitors included in the BD P800* tube. There was preservation of GLP-1, GIP, OXM and glucagon in the P800 plasma samples with half-lives > 96, 96, 72, and 45 hours at room temperature (RT), respectively. In the BD P700* plasma samples, the stabilization of GLP-1 was also achieved with half-life > 96 hours at RT. The stabilization of these variable peptides increased their utility in drug and/or biomarker development. While stability results of GLP-1 obtained with Ab-based assay were consistent with those obtained by MS analysis, the Ab-based results of GIP, Glucagon, and OXM did not reflect the time-dependent degradations revealed by MS analysis. Therefore, we recommended characterizing the degradation of the peptide using the MS-based method when investigating the stability of a specific peptide. PMID:26222180

Mitochondrial neuronal uncoupling proteins: a target for potential disease-modification in Parkinson's disease

PubMed Central

2012-01-01

This review gives a brief insight into the role of mitochondrial dysfunction and oxidative stress in the converging pathogenic processes involved in Parkinson's disease (PD). Mitochondria provide cellular energy in the form of ATP via oxidative phosphorylation, but as an integral part of this process, superoxides and other reactive oxygen species are also produced. Excessive free radical production contributes to oxidative stress. Cells have evolved to handle such stress via various endogenous anti-oxidant proteins. One such family of proteins is the mitochondrial uncoupling proteins (UCPs), which are anion carriers located in the mitochondrial inner membrane. There are five known homologues (UCP1 to 5), of which UCP4 and 5 are predominantly expressed in neural cells. In a series of previous publications, we have shown how these neuronal UCPs respond to 1-methyl-4-phenylpyridinium (MPP+; toxic metabolite of MPTP) and dopamine-induced toxicity to alleviate neuronal cell death by preserving ATP levels and mitochondrial membrane potential, and reducing oxidative stress. We also showed how their expression can be influenced by nuclear factor kappa-B (NF-κB) signaling pathway specifically in UCP4. Furthermore, we previously reported an interesting link between PD and metabolic processes through the protective effects of leptin (hormone produced by adipocytes) acting via UCP2 against MPP+-induced toxicity. There is increasing evidence that these endogenous neuronal UCPs can play a vital role to protect neurons against various pathogenic stresses including those associated with PD. Their expression, which can be induced, may well be a potential therapeutic target for various drugs to alleviate the harmful effects of pathogenic processes in PD and hence modify the progression of this disease. PMID:23210978

Angiogenin in Parkinson Disease Models: Role of Akt Phosphorylation and Evaluation of AAV-Mediated Angiogenin Expression in MPTP Treated Mice

PubMed Central

Steidinger, Trent U.; Slone, Sunny R.; Ding, Huiping; Standaert, David G.; Yacoubian, Talene A.

2013-01-01

The angiogenic factor, angiogenin, has been recently linked to both Amyotrophic Lateral Sclerosis (ALS) and Parkinson Disease (PD). We have recently shown that endogenous angiogenin levels are dramatically reduced in an alpha-synuclein mouse model of PD and that exogenous angiogenin protects against cell loss in neurotoxin-based cellular models of PD. Here, we extend our studies to examine whether activation of the prosurvival Akt pathway is required for angiogenin's neuroprotective effects against 1-methyl-4-phenylpyridinium (MPP+), as observed in ALS models, and to test the effect of virally-mediated overexpression of angiogenin in an in vivo PD model. Using a dominant negative Akt construct, we demonstrate that inhibition of the Akt pathway does not reduce the protective effect of angiogenin against MPP+ toxicity in the dopaminergic SH-SY5Y cell line. Furthermore, an ALS-associated mutant of angiogenin, K40I, which fails to induce Akt phosphorylation, was similar to wildtype angiogenin in protection against MPP+. These results confirm previous work showing neuroprotective effects of angiogenin against MPP+, and indicate that Akt is not required for this protective effect. We also investigated whether adeno-associated viral serotype 2 (AAV2)-mediated overexpression of angiogenin protects against dopaminergic neuron loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model. We found that angiogenin overexpression using this approach does not reduce the MPTP-induced degeneration of dopaminergic cells in the substantia nigra, nor limit the depletion of dopamine and its metabolites in the striatum. Together, these findings extend the evidence for protective effects of angiogenin in vitro, but also suggest that further study of in vivo models is required to translate these effects into meaningful therapies. PMID:23409128

Comparison between two photovoltaic module models based on transistors

NASA Astrophysics Data System (ADS)

Saint-Eve, Frédéric; Sawicki, Jean-Paul; Petit, Pierre; Maufay, Fabrice; Aillerie, Michel

2018-05-01

The main objective of this paper is to verify the possibility to reduce to a simple electronic circuit with very few components the behavior simulation of an un-shaded photovoltaic (PV) module. Particularly, two models based on well-tried elementary structures, i.e., the Darlington structure in first model and the voltage regulation with programmable Zener diode in the second are analyzed. Specifications extracted from the behavior of a real I-V characteristic of a panel are considered and the principal electrical variables are deduced. The two models are expected to match with open circuit voltage, maximum power point (MPP) and short circuit current, without forgetting realistic current slopes on the both sides of MPP. The robustness is mentioned when irradiance varies and is considered as an additional fundamental property. For both models, two simulations are done to identify influence of some parameters. In the first model, a parameter allowing to adjust current slope on left side of MPP proves to be also important for the calculation of open circuit voltage. Besides this model does not authorize an entirely adjustment of I-V characteristic and MPP moves significantly away from real value when irradiance increases. On the contrary, the second model seems to have only qualities: open circuit voltage is easy to calculate, current slopes are realistic and there is perhaps a good robustness when irradiance variations are simulated by adjusting short circuit current of PV module. We have shown that these two simplified models are expected to make reliable and easier simulations of complex PV architecture integrating many different devices like PV modules or other renewable energy sources and storage capacities coupled in parallel association.

Protection against 1-methyl-4-phenyl pyridinium-induced neurotoxicity in human neuroblastoma SH-SY5Y cells by Soyasaponin I by the activation of the phosphoinositide 3-kinase/AKT/GSK3β pathway.

PubMed

Guo, Zheng; Cao, Wei; Zhao, Shifeng; Han, Zengtai; Han, Boxiang

2016-07-06

Parkinson's disease (PD) can be ascribed to the progressive and selective loss of dopaminergic neurons in the substantia nigra pars compacta, and thus molecules with neuroprotective ability may have therapeutic value against PD. In the current study, the neuroprotective effects and underlying mechanisms of Soyasaponin I (Soya-I), a naturally occurring triterpene extracted from a widely used ingredient in many foods, such as Glycine max (soybean), were evaluated in a widely used cellular PD model in which neurotoxicity was induced by 1-methyl-4-phenyl pyridinium (MPP) in cultured SH-SY5Y cells. We found that Soya-I at 10-40 μM considerably protected against MPP-induced neurotoxicity as evidenced by an increase in cell viability, a decrease in lactate dehydrogenase release, and a reduction in apoptotic nuclei. Moreover, Soya-I effectively inhibited the elevated intracellular accumulation of reactive oxygen species as well as the Bax/Bcl-2 ratio caused by MPP. Most importantly, Soya-I markedly reversed the inhibition of protein expression of phosphorylated AKT and phosphorylated GSK3β caused by MPP. LY294002, the specific inhibitor of phosphoinositide 3-kinase, significantly abrogated the upregulated phosphorylated AKT and phosphorylated GSK3β offered by Soya-I, suggesting that the neuroprotection of Soya-I was mainly dependent on the activation of the phosphoinositide 3-kinase/AKT/GSK3β signaling pathway. The results taken together indicate that Soya-I may be a potential candidate for further preclinical study aimed at the prevention and treatment of PD.

Bioprocess automation on a Mini Pilot Plant enables fast quantitative microbial phenotyping.

PubMed

Unthan, Simon; Radek, Andreas; Wiechert, Wolfgang; Oldiges, Marco; Noack, Stephan

2015-03-11

The throughput of cultivation experiments in bioprocess development has drastically increased in recent years due to the availability of sophisticated microliter scale cultivation devices. However, as these devices still require time-consuming manual work, the bottleneck was merely shifted to media preparation, inoculation and finally the analyses of cultivation samples. A first step towards solving these issues was undertaken in our former study by embedding a BioLector in a robotic workstation. This workstation already allowed for the optimization of heterologous protein production processes, but remained limited when aiming for the characterization of small molecule producer strains. In this work, we extended our workstation to a versatile Mini Pilot Plant (MPP) by integrating further robotic workflows and microtiter plate assays that now enable a fast and accurate phenotyping of a broad range of microbial production hosts. A fully automated harvest procedure was established, which repeatedly samples up to 48 wells from BioLector cultivations in response to individually defined trigger conditions. The samples are automatically clarified by centrifugation and finally frozen for subsequent analyses. Sensitive metabolite assays in 384-well plate scale were integrated on the MPP for the direct determination of substrate uptake (specifically D-glucose and D-xylose) and product formation (specifically amino acids). In a first application, we characterized a set of Corynebacterium glutamicum L-lysine producer strains and could rapidly identify a unique strain showing increased L-lysine titers, which was subsequently confirmed in lab-scale bioreactor experiments. In a second study, we analyzed the substrate uptake kinetics of a previously constructed D-xylose-converting C. glutamicum strain during cultivation on mixed carbon sources in a fully automated experiment. The presented MPP is designed to face the challenges typically encountered during early-stage bioprocess development. Especially the bottleneck of sample analyses from fast and parallelized microtiter plate cultivations can be solved using cutting-edge robotic automation. As robotic workstations become increasingly attractive for biotechnological research, we expect our setup to become a template for future bioprocess development.

Insertion and assembly of the precursor of subunit II into the photosystem I complex may precede its processing.

PubMed Central

Cohen, Y; Steppuhn, J; Herrmann, R G; Yalovsky, S; Nechushtai, R

1992-01-01

The biogenesis and assembly of subunit II of photosystem I (PSI) (psaD gene product) were studied and characterized. The precursor and the mature form were produced in vitro and incubated with intact plastids or isolated thylakoids. Following import of the precursor into isolated plastids, mostly the mature form of subunit II was found in the thylakoids. However, when the processing activity was inhibited only the precursor form was present in the membranes. The precursor was processed by a stromal peptidase and processing could occur before or after insertion of the precursor into the thylakoids. Following insertion into isolated thylakoids, both the precursor and the mature form of subunit II were confined to the PSI complex. Insertion of the mature form of subunit II was much less efficient than that of the precursor. Kinetic studies showed that the precursor was inserted into the membrane. Only at a later stage, the mature form began to accumulate. These results suggest that in vivo the precursor of subunit II is inserted and embedded in the thylakoids, as part of the PSI complex. Only later, it is processed to the mature form through the action of a stromal peptidase. Images PMID:1740118

Rogers-Schur-Ramanujan Type Identities for the M(p,p') Minimal Models of Conformal Field Theory

NASA Astrophysics Data System (ADS)

Berkovich, Alexander; McCoy, Barry M.; Schilling, Anne

We present and prove Rogers-Schur-Ramanujan (Bose/Fermi) type identities for the Virasoro characters of the minimal model M(p,p'). The proof uses the continued fraction decomposition of p'/p introduced by Takahashi and Suzuki for the study of the Bethe's Ansatz equations of the XXZ model and gives a general method to construct polynomial generalizations of the fermionic form of the characters which satisfy the same recursion relations as the bosonic polynomials of Forrester and Baxter. We use this method to get fermionic representations of the characters for many classes of r and s.

Uncaria rhynchophylla Ameliorates Parkinson's Disease by Inhibiting HSP90 Expression: Insights from Quantitative Proteomics.

PubMed

Lan, Yu-Long; Zhou, Jun-Jun; Liu, Jing; Huo, Xiao-Kui; Wang, Ya-Li; Liang, Jia-Hao; Zhao, Jian-Chao; Sun, Cheng-Peng; Yu, Zhen-Long; Fang, Lin-Lin; Tian, Xiang-Ge; Feng, Lei; Ning, Jing; Zhang, Bao-Jing; Wang, Chao; Zhao, Xin-Yu; Ma, Xiao-Chi

2018-06-21

Uncaria rhynchophylla, known as "Gou-teng", is a traditional Chinese medicine (TCM) used to extinguish wind, clear heat, arrest convulsions, and pacify the liver. Although U. rhynchophylla has a long history of being often used to treat central nervous system (CNS) diseases, its efficacy and potential mechanism are still uncertain. This study investigated neuroprotective effect and the underlying mechanism of U. rhynchophylla extract (URE) in MPP+-induced SH-SY5Y cells and MPTP-induced mice. MPP+-induced SH-SY5Y cells and MPTP-induced mice were used to established Parkinson's disease (PD) models. Quantitative proteomics and bioinformatics were used to uncover proteomics changes of URE. Western blotting was used to validate main differentially expressed proteins and test HSP90 client proteins (apoptosis-related, autophagy-related, MAPKs, PI3K, and AKT proteins). Flow cytometry and JC-1 staining assay were further used to confirm the effect of URE on MPP+-induced apoptosis in SH-SY5Y cells. Gait analysis was used to detect the behavioral changes in MPTP-induced mice. The levels of dopamine (DA) and their metabolites were examined in striatum (STR) by HPLC-EC. The positive expression of tyrosine hydroxylase (TH) was detected by immunohischemical staining and Western blotting. URE dose-dependently increased the cell viability in MPP+-induced SH-SY5Y cells. Quantitative proteomics and bioinformatics results confirmed that HSP90 was an important differentially expressed protein of URE. URE inhibited the expression of HSP90, which further reversed MPP+-induced cell apoptosis and autophagy by increasing the expressions of Bcl-2, Cyclin D1, p-ERK, p-PI3K p85, PI3K p110α, p-AKT, and LC3-I and decreasing cleaved caspase 3, Bax, p-JNK, p-p38, and LC3-II. URE also markedly decreased the apoptotic ratio and elevated mitochondrial transmembrane potential (DΨm). Furthermore, URE treatment ameliorated behavioral impairments, increased the contents of DA and its metabolites and elevated the positive expressions of TH in SN and STR as well as the TH protein. URE possessed the neuroprotective effect in vivo and in vitro, regulated MAPK and PI3K-AKT signal pathways, and inhibited the expression of HSP90. U. rhynchophylla has potentials as therapeutic agent in PD treatment. © 2018 The Author(s). Published by S. Karger AG, Basel.

Sphingosine kinase 2 and sphingosine-1-phosphate promotes mitochondrial function in dopaminergic neurons of mouse model of Parkinson's disease and in MPP+ -treated MN9D cells in vitro.

PubMed

Sivasubramanian, M; Kanagaraj, N; Dheen, S T; Tay, S S W

2015-04-02

Dysregulation of sphingolipid metabolism has been shown to trigger the pathophysiology of many neurodegenerative disorders. The present study focuses on the role of one of the two sphingosine kinases, Sphk2 and its metabolite sphingosine-1-phosphate (S1P) signaling in Parkinson's disease (PD). Our study indicated a marked down regulation of Sphk2 expression in the substantia nigra region of the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model and in the cellular PD model. Localization studies indicated that Sphk2 was predominantly present in mitochondria, proposing for its potential role in mitochondrial functions. Since mitochondrial dysfunction has been described to be the major pathological event in PD, the present study focused on the role of Sphk2/S1P signaling in promoting mitochondrial functions in the MPTP-induced mouse model of PD and in 1-methyl-4 phenylpyridinium (MPP(+))-treated MN9D cells. Our study demonstrated that inhibition of Sphk2 decreased the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and its downstream targets nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM) which are the key genes regulating mitochondrial function. In addition, there was also a significant reduction in the total cellular adenosine triphosphate (ATP) and superoxide dismutase 2 (SOD 2) with an associated increase in levels of reactive oxygen species (ROS) in the absence of Sphk2. Interestingly, it was found that treating the cells with exogenous S1P along with MPP(+) exerted a neuroprotective effect by activation of p-CREB, PGC-1α and NRF-1 in the MN9D cells. Moreover, the level of ATP was unaffected in the MPP(+)-treated cells in the presence of S1P. It was also observed that levels of ROS were significantly decreased in the MPP(+)-treated cells in the presence of exogenous S1P. Our study also demonstrated that S1P exerted its protective effect through the S1P1 receptor. Taken together, these results show that Sphk2/S1P has an important role to play in the survival of the dopaminergic neurons, in the pathogenesis of PD. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Tissue distribution of a novel neurotensin-degrading metallopeptidase. An immunological approach using monospecific polyclonal antibodies.

PubMed

Checler, F; Barelli, H; Vincent, J P

1989-01-15

A monospecific polyclonal antiserum was raised against a recently purified rat brain neurotensin-degrading metallopeptidase. The purified IgG fraction immunoprecipitated the peptidase and inhibited its proteolytic activity. Western blot analyses revealed that the immune fraction recognizes only one protein in rat brain homogenates, and this corresponds closely to the purified enzyme. The IgG displayed a restricted specificity towards the peptidase from murine origin. In the rat, the neurotensin-degrading enzyme was widely distributed throughout peripheral organs with the noticeable exception of the duodenum. In addition, the peptidase was detected in various cell lines or membrane preparations of neural or extraneural origin in which it had been previously characterized by means of biochemical methods. In light of this widespread distribution, the putative role of the peptidase in the metabolism of neuropeptides is discussed.

A genetic study of various enzyme polymorphisms in Pleurodeles waltlii (Urodele Amphibian). II. Peptidases: demonstration of sex linkage.

PubMed

Ferrier, V; Gasser, F; Jaylet, A; Cayrol, C

1983-06-01

The existence of four peptidases was demonstrated by starch gel electrophoresis in Pleurodeles waltlii: PEP-1, PEP-2, PEP-3, and PEP-4. Peptidases-3 and -4 are monomorphic, and peptidases-1 and -2 are polymorphic. The heredity of the polymorphisms was studied using individuals arising from crosses or of gynogenetic origin. Peptidase-1 is dimeric; its polymorphism depends on a pair of codominant alleles, Pep-1A and Pep-1B, which are situated on the Z and W sex chromosomes, respectively, in close proximity to, or even within, the sex differential segment. As the differential segment is very close to the centromere, the PEP-1 locus therefore also appears to be closely linked to it. Expression of the PEP-1 locus was shown to be independent of the sex hormone environment. This locus is the first case reported in amphibians of an enzyme marker linked to the genetic sex. It allows the sex of PLeurodeles to be determined before they reach sexual maturity. Peptidase-2 is monomeric. Its polymorphism depends on a pair of codominant alleles on an autosomal PEP-2 locus. The high proportion of heterozygous animals in the gynogenetic offspring of females heterozygous for the PEP-2 locus indicates segregation which is independent of the centromere. Analysis of the offspring of doubly heterozygous females (i.e., for two of the loci--LDH-B, G6PDH, PEP-1, and PEP-2) shows that the four loci are independent.

Phenotypic Characterization of Retinoic Acid Differentiated SH-SY5Y Cells by Transcriptional Profiling

PubMed Central

Korecka, Joanna A.; van Kesteren, Ronald E.; Blaas, Eva; Spitzer, Sonia O.; Kamstra, Jorke H.; Smit, August B.; Swaab, Dick F.; Verhaagen, Joost; Bossers, Koen

2013-01-01

Multiple genetic and environmental factors play a role in the development and progression of Parkinson’s disease (PD). The main neuropathological hallmark of PD is the degeneration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta. To study genetic and molecular contributors to the disease process, there is a great need for readily accessible cells with prominent DAergic features that can be used for reproducible in vitro cellular screening. Here, we investigated the molecular phenotype of retinoic acid (RA) differentiated SH-SY5Y cells using genome wide transcriptional profiling combined with gene ontology, transcription factor and molecular pathway analysis. We demonstrated that RA induces a general neuronal differentiation program in SH-SY5Y cells and that these cells develop a predominantly mature DAergic-like neurotransmitter phenotype. This phenotype is characterized by increased dopamine levels together with a substantial suppression of other neurotransmitter phenotypes, such as those for noradrenaline, acetylcholine, glutamate, serotonin and histamine. In addition, we show that RA differentiated SH-SY5Y cells express the dopamine and noradrenalin neurotransmitter transporters that are responsible for uptake of MPP(+), a well known DAergic cell toxicant. MPP(+) treatment alters mitochondrial activity according to its proposed cytotoxic effect in DAergic neurons. Taken together, RA differentiated SH-SY5Y cells have a DAergic-like phenotype, and provide a good cellular screening tool to find novel genes or compounds that affect cytotoxic processes that are associated with PD. PMID:23724009

Glycogen synthase kinase-3 inhibitors reverse deficits in long-term potentiation and cognition in Fragile X mice

PubMed Central

Franklin, Aimee V.; King, Margaret K.; Palomo, Valle; Martinez, Ana; McMahon, Lori L.; Jope, Richard S.

2013-01-01

Background Identifying feasible therapeutic interventions is crucial for ameliorating the intellectual disability and other afflictions of Fragile X Syndrome (FXS), the most common inherited cause of intellectual disability and autism. Hippocampal glycogen synthase kinase-3 (GSK3) is hyperactive in the mouse model of FXS (FX mice), and hyperactive GSK3 promotes locomotor hyperactivity and audiogenic seizure susceptibility in FX mice, raising the possibility that specific GSK3 inhibitors may improve cognitive processes. Methods We tested if specific GSK3 inhibitors improve deficits in N-methyl-D-aspartate receptor (NMDAR)-dependent long term potentiation (LTP) at medial perforant path synapses onto dentate granule cells (MPP-DGC) and dentate gyrus-dependent cognitive behavioral tasks. Results GSK3 inhibitors completely rescued deficits in LTP at MPP-DGC synapses in FX mice. Furthermore, synaptosomes from the dentate gyrus of FX mice displayed decreased inhibitory serine-phosphorylation of GSK3β compared with wild-type littermates. The potential therapeutic utility of GSK3 inhibitors was further tested on dentate gyrus-dependent congnitive behaviors. In vivo administration of GSK3 inhibitors completely reversed impairments in several cognitive tasks in FX mice, including novel object detection, coordinate and categorical spatial processing, and temporal ordering for visual objects. Conclusions These findings establish that synaptic plasticity and cognitive deficits in FX mice can be improved by intervention with inhibitors of GSK3, which may prove therapeutically beneficial in FXS. PMID:24041505

Digestive proteolysis in the Colorado potato beetle, Leptinotarsa decemlineata: Activity-based profiling and imaging of a multipeptidase network.

PubMed

Srp, Jaroslav; Nussbaumerová, Martina; Horn, Martin; Mareš, Michael

2016-11-01

The Colorado potato beetle (CPB), Leptinotarsa decemlineata, is a major pest of potato plants, and its digestive system is a promising target for development of pest control strategies. This work focuses on functional proteomic analysis of the digestive proteolytic enzymes expressed in the CPB gut. We identified a set of peptidases using imaging with specific activity-based probes and activity profiling with selective substrates and inhibitors. The secreted luminal peptidases were classified as: (i) endopeptidases of cathepsin D, cathepsin L, and trypsin types and (ii) exopeptidases with aminopeptidase (cathepsin H), carboxypeptidase (serine carboxypeptidase, prolyl carboxypeptidase), and carboxydipeptidase (cathepsin B) activities. The proteolytic arsenal also includes non-luminal peptidases with prolyl oligopeptidase and metalloaminopeptidase activities. Our results indicate that the CPB gut employs a multienzyme network of peptidases with complementary specificities to efficiently degrade ingested proteins. This proteolytic system functions in both CPB larvae and adults and is controlled mainly by cysteine and aspartic peptidases and supported by serine and metallopeptidases. The component enzymes identified here are potential targets for inhibitors with tailored specificities that could be engineered into potato plants to confer resistance to CPB. Copyright © 2016 Elsevier Ltd. All rights reserved.

Peptidase activity as a determinant of agonist potencies in some smooth muscle preparations.

PubMed

Hall, J M; Fox, A J; Morton, I K

1990-02-06

The influence of degradation by peptidases on concentration-response relationships for peptide agonists of the tachykinin and bombesin-like families was investigated. The combined presence of three peptidase inhibitors, phosphoramidon (1 microM), captopril (1 microM) and bestatin (100 microM), had no significant effect on the onset rates or peak contractile responses to these peptides in the rat urinary bladder and guinea-pig taenia caeci preparations, or on their peak potentiation of the contractile response to field-stimulation in the guinea-pig vas deferens preparation. However, rates of offset of the response to tachykinins were markedly prolonged in tissues treated with peptidase inhibitors. In experiments designed to estimate clearance of applied peptide from the organ bath, there was an initial rate of loss with the guinea-pig vas deferens and taenia caeci which, measured over the first 5 min, had a half-time of 2-3 min which was then prolonged to 6-8 min in the presence of peptidase inhibitors. These results show that although peptide breakdown can be demonstrated in these systems, it seems not to be an important determinant of relative pharmacological activity measured in terms of peak response.

The optimal frequency of aquatic physiotherapy for individuals with chronic musculoskeletal pain: a randomised controlled trial.

PubMed

Cuesta-Vargas, Antonio I; White, Melanie; González-Sánchez, Manuel; Kuisma, Raija

2015-01-01

To establish whether there was a difference in health-related quality of life (HRQoL) in people with chronic musculoskeletal disorders (PwCMSKD) after participating in a multimodal physiotherapy program (MPP) either two or three sessions a week. Total of 114 PwCMSKD participated in this prospective randomised controlled trial. An individualised MPP, consisting of exercises for mobility, motor-control, muscle strengthening, cardiovascular training, and health education, was implemented either twice a week (G2: n = 58) or three times a week) (G3: n = 56) for 1 year. HRQoL physical and mental health state (PHS/MHS), Roland Morris disability Questionnaire (RMQ), Neck-Disability-Index (NDI) and Western Ontario and McMaster Universities' Arthritis Index (WOMAC) were used to measure outcomes of MPP for people with chronic low back pain, chronic neck pain and osteoarthritis, respectively. Measures were taken at baseline, 8 weeks (8 w), 6 months (6 m), and 1 year (1 y) after starting the programme. No statistically significant differences were found between the two groups (G2 and G3), except in NDI at 8 w (-3.34, (CI 95%: -6.94/0.84, p = 0.025 (scale 0-50)). All variables showed improvement reaching the following values (from baseline to 1 y) G2: PHS: 57.72 (baseline: 41.17; (improvement: 16.55%), MHS: 74.51 (baseline: 47.46, 27.05%), HRQoL 0.90 (baseline: 0.72, 18%)), HRQoL-VAS 84.29 (baseline: 58.04, 26.25%), RMQ 4.15 (baseline: 7.85, 15.42%), NDI 3.96 (baseline: 21.87, 35.82%), WOMAC 7.17 (baseline: 25.51, 19.10%). G3: PHS: 58.64 (baseline: 39.75, 18.89%), MHS: 75.50 (baseline: 45.45, (30.05%), HRQoL 0.67 (baseline: 0.88, 21%), HRQoL-VAS 86.91 (baseline: 52.64, 34.27%), RMQ 4.83 (baseline: 8.93, 17.08%), NDI 4.91 (baseline: 23.82, 37.82%), WOMAC 6.35 (baseline: 15.30, 9.32%). No significant differences between the two groups were found in the outcomes of a MPP except in the NDI at 8 weeks, but both groups improved in all variables during the course of 1 year under study. Implications for Rehabilitation A multimodal physiotherapy program (MPP) improves quality of life, overall health, and function in people with chronic musculoskeletal disease after an intervention of short, medium and long term. This implies that twice a week MPP for people with chronic musculoskeletal pain has comparable results to three times a week provision and therefore may have implications in saving resources and cost for patients and service providers without compromising the outcomes of treatment. These results can be considered not only for therapists, but also for managers who offer the services to optimise the balance cost-effectiveness of the proposed interventions.

The catalytic mechanism of DD-peptidases: unexpected importance of tyrosine 280 in the transpeptidation reaction catalysed by the Streptomyces R61 DD-peptidase.

PubMed

Wilkin, J M; Lamotte-Brasseur, J; Frère, J M

1998-07-01

The study of the interactions between the Tyr280Phe mutant of the Streptomyces R61 DD-peptidase, various substrates and beta-lactam antibiotics shows that Tyr280 is involved not only in the formation of the acylenzyme with the peptide substrate and beta-lactam antibiotics, but also and specifically in the catalysis of the transpeptidation reaction. Surprisingly, this residue does not belong to the conserved structural and functional elements which characterise the penicillin-recognising enzymes.

Membrane peptidases in the pig choroid plexus and on other cell surfaces in contact with the cerebrospinal fluid.

PubMed Central

Bourne, A; Barnes, K; Taylor, B A; Turner, A J; Kenny, A J

1989-01-01

A comprehensive survey of 11 peptidases, all of which are markers for renal microvillar membranes, has been made in membrane fractions prepared from pig choroid plexus. Two fractionation schemes were explored, both depending on a MgCl2-precipitation step, the preferred one having advantages in speed and yield of the activities. The specific activities of the peptidases in the choroid-plexus membranes were, with the exception of carboxypeptidase M, lower than in renal microvillar membranes: those of aminopeptidase N, peptidyl dipeptidase A ('angiotensin-converting enzyme') and gamma-glutamyltransferase were 3-5-fold lower, those of aminopeptidase A and endopeptidase-24.11 were 12-15 fold lower, and those of dipeptidyl peptidase IV and aminopeptidase W were 50-70-fold lower. Carboxypeptidase M had a similar activity in both membranes. Alkaline phosphatase and (Na+ + K+)-activated ATPase were more active in the choroid-plexus membranes. No activity for microsomal dipeptidase, aminopeptidase P and carboxypeptidase P could be detected. Six of the peptidases and (Na+ + K+)-activated ATPase were also studied by immunoperoxidase histochemistry at light- and electron-microscopic levels. Endopeptidase-24.11 and (Na+ + K+)-activated ATPase were uniquely located on the brush border, and the other two peptidases appeared to be much more abundant on the endothelial lining of microvessels. Dipeptidyl peptidase IV and aminopeptidase W were also detected in microvasculature. Pial membranes associated with the brain and spinal cord also stained positively for endopeptidase-24.11, aminopeptidase N and peptidyl dipeptidase A. The immunohistochemical studies indicated the subcellular fractionation did not discriminate between membranes derived from epithelial cells (i.e. microvilli) and those from endothelial cells. The possible significance of these studies in relation to neuropeptide metabolism and the control of cerebrospinal fluid production is discussed. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. PMID:2655579

Tissue distribution of a novel neurotensin-degrading metallopeptidase. An immunological approach using monospecific polyclonal antibodies.

PubMed Central

Checler, F; Barelli, H; Vincent, J P

1989-01-01

A monospecific polyclonal antiserum was raised against a recently purified rat brain neurotensin-degrading metallopeptidase. The purified IgG fraction immunoprecipitated the peptidase and inhibited its proteolytic activity. Western blot analyses revealed that the immune fraction recognizes only one protein in rat brain homogenates, and this corresponds closely to the purified enzyme. The IgG displayed a restricted specificity towards the peptidase from murine origin. In the rat, the neurotensin-degrading enzyme was widely distributed throughout peripheral organs with the noticeable exception of the duodenum. In addition, the peptidase was detected in various cell lines or membrane preparations of neural or extraneural origin in which it had been previously characterized by means of biochemical methods. In light of this widespread distribution, the putative role of the peptidase in the metabolism of neuropeptides is discussed. Images Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:2649078

Peptidase inhibitors potentiate the effects of neurotensin and neuromedin N on self-stimulation of the medial prefrontal cortex.

PubMed

Fernández, R; Alba, F; Ferrer, J M

1996-02-29

The purpose of this study was to examine the possible role of endogenous peptidases in the inhibition of intracranial self-stimulation (ICSS) produced by injections of neurotensin (NT) and neuromedin N (NN) into the medial prefrontal cortex (MPC) of the rat. We studied the effects on ICSS of the MPC of the administration of thiorphan and bestatin, two specific inhibitors of the peptidases that inactivate NT and NN respectively. Microinjections into MPC of thiorphan (10 micrograms) and bestatin (25 micrograms) potentiated in inhibition of ICSS produced by the intracortical administration of NT (10 nmol) and NN (20 nmol) respectively. This potentiation affected both the amplitude and the duration of the inhibition of ICSS produced by the neuropeptides. Our data indicate that endogenous peptidases are involved in the inactivation of NT and NN in the prefrontal cortex.

Muco-inert nanoparticle probes and drug carriers

NASA Astrophysics Data System (ADS)

Wang, Ying-Ying

2011-12-01

Mucus coats the exposed surfaces of the eyes and respiratory, gastrointestinal (GI) and cervicovaginal (CV) tracts, and protects mucosal tissues against pathogens and other foreign particulates. Most foreign particles are effectively trapped in mucus through steric and adhesive interactions, and are rapidly eliminated by different mucus clearance mechanisms. Nevertheless, mucus also immobilizes conventional drug and gene carriers, thereby precluding sustained and targeted drug delivery to mucosal sites. Synthetic particles engineered with muco-inert surfaces, and some viruses, can readily penetrate mucus gel, and may serve as useful probes to understand the biophysical barrier properties of mucus. Improved understanding of the mucus barrier could provide insights into methods to enhance drug and gene delivery at mucosal surfaces, as well as understanding the occasional failure of mucus to protect against infection or injury. Recently, muco-inert nanoparticles were developed by conjugating a dense layer of low MW polyethylene glycol to particle surfaces. Since they are slowed only by steric obstruction from the mucus mesh, various sized muco-inert nanoparticles can be used to probe the microstructure and microrheology of mucus. I applied this technique to determine whether the mucus barrier may be altered by exogenous factors, including the presence of detergent, pH changes and synthetic nanoparticles. I first studied the microrheology of native human cervicovaginal mucus (CVM), and found that CVM behaves as a viscoelastic solid at length scales ≥ 1 microm (preventing large particles from diffusing through) but as a viscoelastic liquid at length scales up to at least 500 nm (allowing smaller particles to diffuse through low viscosity fluid-filled pores). Treating CVM with a nonionic detergent, N9, shifted the viscoelastic liquid-solid transition point to < 200 nm, suggesting hydrophobic interactions between mucin fibers play an important role in regulating the mucus microstructure and consequently the microrheology. Indeed, N9 caused the average mucus pore size to decrease from ˜340 nm to 130 nm. I then looked at the effect of pH on mucus and found that the microstructure of CVM is essentially pH-independent over a broad range of physiological pH. Between pH 4 (the native pH of CVM) and 6--7, the average pore size in the mucus mesh remained unchanged, and between pH 1--2 and 8--9, there was at most a 2-fold drop in the average pore size (likely due to changes in electrostatic vs. hydrophobic interactions between mucin fibers). Finally, I found that mucoadhesive synthetic nanoparticles, at sufficiently high concentrations, can bundle mucin fibers and create large openings in the mucus microstructure. Disruption of the mucus barrier in this manner allowed a greater fraction of large (1 microm) muco-inert particles to diffuse through the mucus mesh. Muco-inert nanoparticles---also referred to as "mucus-penetrating particles" (MPP)---offer the potential for sustained and targeted drug delivery to mucosal surfaces. By penetrating luminal mucus layers, MPP may be able to reach the slowly cleared adherent mucus layer or deep folds of the epithelium and thereby achieve prolonged retention. I first measured the long range penetration of MPP compared to conventional mucoadhesive particles (CP) into CVM. With minimal dilution of CVM, MPP could penetrate up to 200 microm over 1 hr with ˜530 particles/mm2 penetrating 100 microm or more, while CP remained immobilized (note that physiological mucus layer thicknesses are no more than ˜200 microm). Furthermore, with 30% v/v dilution, MPP could penetrate up to 1.5 mm over 1 hr with ˜74,000 particles/mm2 penetrating 100 microm or more, while CP continued to remain stuck. I then studied the distribution and retention of MPP vs. CP in the mouse vagina to determine whether improved mucus penetration leads to more uniform distribution and prolonged retention. I found that MPP were not only more uniformly distributed in the vaginal lumen, but also penetrated deep into epithelial folds. In contrast, CP were aggregated by luminal mucus and failed to reach the epithelium. Several-fold more MPP were retained on the vaginal epithelial surface than CP over at least ˜1 day. Drug and gene carriers that provide more uniform and longer-lasting coverage of mucosal surfaces may greatly improve the treatment or prevention of diseases at mucosal sites.

Prokaryote-derived protein inhibitors of peptidases: a sketchy occurrence and mostly unknown function

PubMed Central

Kantyka, Tomasz; Rawlings, Neil D.; Potempa, Jan

2010-01-01

In metazoan organisms protein inhibitors of peptidases are important factors essential for regulation of proteolytic activity. In vertebrates genes encoding peptidase inhibitors constitute up to 1% of genes reflecting a need for tight and specific control of proteolysis especially in extracellular body fluids. In stark contrast unicellular organisms, both prokaryotic and eukaryotic consistently contain only few, if any, genes coding for putative peptidase inhibitors. This may seem perplexing in the light of the fact that these organisms produce large numbers of proteases of different catalytic classes with the genes constituting up to 6% of the total gene count with the average being about 3%. Apparently, however, a unicellular life-style is fully compatible with other mechanisms of regulation of proteolysis and does not require protein inhibitors to control their intracellular and extracellular proteolytic activity. So in prokaryotes occurrence of genes encoding different types of peptidase inhibitors is infrequent and often scattered among phylogenetically distinct orders or even phyla of microbiota. Genes encoding proteins homologous to alpha-2-macroglobulin (family I39), serine carboxypeptidase Y inhibitor (family I51), alpha-1-peptidase inhibitor (family I4) and ecotin (family I11) are the most frequently represented in Bacteria. Although several of these gene products were shown to possess inhibitory activity, with an exception of ecotin and staphostatins, the biological function of microbial inhibitors is unclear. In this review we present distribution of protein inhibitors from different families among prokaryotes, describe their mode of action and hypothesize on their role in microbial physiology and interactions with hosts and environment. PMID:20558234

Purification and characterization of a novel neurotensin-degrading peptidase from rat brain synaptic membranes.

PubMed

Checler, F; Vincent, J P; Kitabgi, P

1986-08-25

A peptidase that cleaved neurotensin at the Pro10-Tyr11 peptide bond, leading to the formation of neurotensin-(1-10) and neurotensin-(11-13), was purified nearly to homogeneity from rat brain synaptic membranes. The enzyme appeared to be monomeric with a molecular weight of about 70,000-75,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and high pressure liquid chromatography filtration. Isoelectrofocusing indicated a pI of 5.9-6. The purified peptidase could be classified as a neutral metallopeptidase with respect to its sensitivity to pH and metal chelators. Thiol-blocking agents and acidic and serine protease inhibitors had no effect. Studies with specific peptidase inhibitors clearly indicated that the purified enzyme was distinct from enzymes capable of cleaving neurotensin at the Pro10-Tyr11 bond such as proline endopeptidase and endopeptidase 24-11. The enzyme was also distinct from other neurotensin-degrading peptidases such as angiotensin-converting enzyme and a recently purified rat brain soluble metalloendopeptidase. The peptidase displayed a high affinity for neurotensin (Km = 2.6 microM). Studies on its specificity revealed that neurotensin-(9-13) was the shortest neurotensin partial sequence that was able to fully inhibit [3H]neurotensin degradation. Shortening the C-terminal end of the neurotensin molecule as well as substitutions in positions 8, 9, and 11 by D-amino acids strongly decreased the inhibitory potency of neurotensin. Among 20 natural peptides, only angiotensin I and the neurotensin-related peptides (xenopsin and neuromedin N) were found as potent as unlabeled neurotensin.

Competitive Inhibition of the Endoplasmic Reticulum Signal Peptidase by Non-cleavable Mutant Preprotein Cargos*

PubMed Central

Cui, Jingqiu; Chen, Wei; Sun, Jinhong; Guo, Huan; Madley, Rachel; Xiong, Yi; Pan, Xingyi; Wang, Hongliang; Tai, Andrew W.; Weiss, Michael A.; Arvan, Peter; Liu, Ming

2015-01-01

Upon translocation across the endoplasmic reticulum (ER) membrane, secretory proteins are proteolytically processed to remove their signal peptide by signal peptidase (SPase). This process is critical for subsequent folding, intracellular trafficking, and maturation of secretory proteins. Prokaryotic SPase has been shown to be a promising antibiotic target. In contrast, to date, no eukaryotic SPase inhibitors have been reported. Here we report that introducing a proline immediately following the natural signal peptide cleavage site not only blocks preprotein cleavage but also, in trans, impairs the processing and maturation of co-expressed preproteins in the ER. Specifically, we find that a variant preproinsulin, pPI-F25P, is translocated across the ER membrane, where it binds to the catalytic SPase subunit SEC11A, inhibiting SPase activity in a dose-dependent manner. Similar findings were obtained with an analogous variant of preproparathyroid hormone, demonstrating that inhibition of the SPase does not depend strictly on the sequence or structure of the downstream mature protein. We further show that inhibiting SPase in the ER impairs intracellular processing of viral polypeptides and their subsequent maturation. These observations suggest that eukaryotic SPases (including the human ortholog) are, in principle, suitable therapeutic targets for antiviral drug design. PMID:26446786

Functional analysis of C1 family cysteine peptidases in the larval gut of Тenebrio molitor and Tribolium castaneum.

PubMed

Martynov, Alexander G; Elpidina, Elena N; Perkin, Lindsey; Oppert, Brenda

2015-02-14

Larvae of the tenebrionids Tenebrio molitor and Tribolium castaneum have highly compartmentalized guts, with primarily cysteine peptidases in the acidic anterior midgut that contribute to the early stages of protein digestion. High throughput sequencing was used to quantify and characterize transcripts encoding cysteine peptidases from the C1 papain family in the gut of tenebrionid larvae. For T. castaneum, 25 genes and one questionable pseudogene encoding cysteine peptidases were identified, including 11 cathepsin L or L-like, 11 cathepsin B or B-like, and one each F, K, and O. The majority of transcript expression was from two cathepsin L genes on chromosome 10 (LOC659441 and LOC659502). For cathepsin B, the major expression was from genes on chromosome 3 (LOC663145 and LOC663117). Some transcripts were expressed at lower levels or not at all in the larval gut, including cathepsins F, K, and O. For T. molitor, there were 29 predicted cysteine peptidase genes, including 14 cathepsin L or L-like, 13 cathepsin B or B-like, and one each cathepsin O and F. One cathepsin L and one cathepsin B were also highly expressed, orthologous to those in T. castaneum. Peptidases lacking conservation in active site residues were identified in both insects, and sequence analysis of orthologs indicated that changes in these residues occurred prior to evolutionary divergence. Sequences from both insects have a high degree of variability in the substrate binding regions, consistent with the ability of these enzymes to degrade a variety of cereal seed storage proteins and inhibitors. Predicted cathepsin B peptidases from both insects included some with a shortened occluding loop without active site residues in the middle, apparently lacking exopeptidase activity and unique to tenebrionid insects. Docking of specific substrates with models of T. molitor cysteine peptidases indicated that some insect cathepsins B and L bind substrates with affinities similar to human cathepsin L, while others do not and have presumably different substrate specificity. These studies have refined our model of protein digestion in the larval gut of tenebrionid insects, and suggest genes that may be targeted by inhibitors or RNA interference for the control of cereal pests in storage areas.

Kinetics and stereochemistry of hydrolysis of an N-(phenylacetyl)-α-hydroxyglycine ester catalyzed by serine β-lactamases and DD-peptidases.

PubMed

Pelto, Ryan B; Pratt, R F

2012-09-28

The α-hydroxydepsipeptide 3-carboxyphenyl N-(phenylacetyl)-α-hydroxyglycinate (5) is a quite effective substrate of serine β-lactamases and low molecular mass DD-peptidases. The class C P99 and ampC β-lactamases catalyze the hydrolysis of both enantiomers of 5, although they show a strong preference for one of them. The class A TEM-2 and class D OXA-1 β-lactamases and the Streptomyces R61 and Actinomadura R39 DD-peptidases catalyze hydrolysis of only one enantiomer of at any significant rate. Experiments show that all of the above enzymes strongly prefer the same enantiomer, a surprising result since β-lactamases usually prefer L(S) enantiomers and DD-peptidases D(R). Product analysis, employing peptidylglycine α-amidating lyase, showed that the preferred enantiomer is D(R). Thus, it is the β-lactamases that have switched preference rather than the DD-peptidases. Molecular modeling of the P99 β-lactamase active site suggests that the α-hydroxyl 5 of may interact with conserved Asn and Lys residues. Both α-hydroxy and α-amido substituents on a glycine ester substrate can therefore enhance its productive interaction with the β-lactamase active site, although their effects are not additive; this may also be true for inhibitors.

Molecular cloning of a cDNA encoding the glycoprotein of hen oviduct microsomal signal peptidase.

PubMed Central

Newsome, A L; McLean, J W; Lively, M O

1992-01-01

Detergent-solubilized hen oviduct signal peptidase has been characterized previously as an apparent complex of a 19 kDa protein and a 23 kDa glycoprotein (GP23) [Baker & Lively (1987) Biochemistry 26, 8561-8567]. A cDNA clone encoding GP23 from a chicken oviduct lambda gt11 cDNA library has now been characterized. The cDNA encodes a protein of 180 amino acid residues with a single site for asparagine-linked glycosylation that has been directly identified by amino acid sequence analysis of a tryptic-digest peptide containing the glycosylated site. Immunoblot analysis reveals cross-reactivity with a dog pancreas protein. Comparison of the deduced amino acid sequence of GP23 with the 22/23 kDa glycoprotein of dog microsomal signal peptidase [Shelness, Kanwar & Blobel (1988) J. Biol. Chem. 263, 17063-17070], one of five proteins associated with this enzyme, reveals that the amino acid sequences are 90% identical. Thus the signal peptidase glycoprotein is as highly conserved as the sequences of cytochromes c and b from these same species and is likely to be found in a similar form in many, if not all, vertebrate species. The data also show conclusively that the dog and avian signal peptidases have at least one protein subunit in common. Images Fig. 1. PMID:1546959

Kv3.4 is modulated by HIF-1α to protect SH-SY5Y cells against oxidative stress-induced neural cell death.

PubMed

Song, Min Seok; Ryu, Pan Dong; Lee, So Yeong

2017-05-18

The Kv3.4 channel is characterized by fast inactivation and sensitivity to oxidation. However, the physiological role of Kv3.4 as an oxidation-sensitive channel has yet to be investigated. Here, we demonstrate that Kv3.4 plays a pivotal role in oxidative stress-related neural cell damage as an oxidation-sensitive channel and that HIF-1α down-regulates Kv3.4 function, providing neuroprotection. MPP + and CoCl 2 are reactive oxygen species (ROS)-generating reagents that induce oxidative stress. However, only CoCl 2 decreases the expression and function of Kv3.4. HIF-1α, which accumulates in response to CoCl 2 treatment, is a key factor in Kv3.4 regulation. In particular, mitochondrial Kv3.4 was more sensitive to CoCl 2 . Blocking Kv3.4 function using BDS-II, a Kv3.4-specific inhibitor, protected SH-SY5Y cells against MPP + -induced neural cell death. Kv3.4 inhibition blocked MPP + -induced cytochrome c release from the mitochondrial intermembrane space to the cytosol and mitochondrial membrane potential depolarization, which are characteristic features of apoptosis. Our results highlight Kv3.4 as a possible new therapeutic paradigm for oxidative stress-related diseases, including Parkinson's disease.

Intelligent energy harvesting scheme for microbial fuel cells: Maximum power point tracking and voltage overshoot avoidance

NASA Astrophysics Data System (ADS)

Alaraj, Muhannad; Radenkovic, Miloje; Park, Jae-Do

2017-02-01

Microbial fuel cells (MFCs) are renewable and sustainable energy sources that can be used for various applications. The MFC output power depends on its biochemical conditions as well as the terminal operating points in terms of output voltage and current. There exists one operating point that gives the maximum possible power from the MFC, maximum power point (MPP), for a given operating condition. However, this MPP may vary and needs to be tracked in order to maintain the maximum power extraction from the MFC. Furthermore, MFC reactors often develop voltage overshoots that cause drastic drops in the terminal voltage, current, and the output power. When the voltage overshoot happens, an additional control measure is necessary as conventional MPPT algorithms will fail because of the change in the voltage-current relationship. In this paper, the extremum seeking (ES) algorithm was used to track the varying MPP and a voltage overshoot avoidance (VOA) algorithm is developed to manage the voltage overshoot conditions. The proposed ES-MPPT with VOA algorithm was able to extract 197.2 mJ during 10-min operation avoiding voltage overshoot, while the ES MPPT-only scheme stopped harvesting after only 18.75 mJ because of the voltage overshoot happened at 0.4 min.

Activation of the HMGB1-RAGE axis upregulates TH expression in dopaminergic neurons via JNK phosphorylation.

PubMed

Kim, Soo Jeong; Ryu, Min Jeong; Han, Jeongsu; Jang, Yunseon; Kim, Jungim; Lee, Min Joung; Ryu, Ilhwan; Ju, Xianshu; Oh, Eungseok; Chung, Woosuk; Kweon, Gi Ryang; Heo, Jun Young

2017-11-04

The derangement of tyrosine hydroxylase (TH) activity reduces dopamine synthesis and is implicated in the pathogenesis of Parkinson's disease. However, the extracellular modulator and intracellular regulatory mechanisms of TH have yet to be identified. Recently, high-mobility group box 1 (HMGB1) was reported to be actively secreted from glial cells and is regarded as a mediator of dopaminergic neuronal loss. However, the mechanism for how HMGB1 affects TH expression, particularly through the receptor for advanced glycation endproducts (RAGE), has not yet been investigated. We found that recombinant HMGB1 (rHMGB1) upregulates TH mRNA expression via simultaneous activation of JNK phosphorylation, and this induction of TH expression is blocked by inhibitors of RAGE and JNK. To investigate how TH expression levels change through the HMGB1-RAGE axis as a result of MPP + toxicity, we co-treated SN4741 dopaminergic cells with MPP + and rHMGB1. rHMGB1 blocked the reduction of TH mRNA following MPP + treatment without altering cell survival rates. Our results suggest that HMGB1 upregulates TH expression to maintain dopaminergic neuronal function via activating RAGE, which is dependent on JNK phosphorylation. Copyright © 2017 Elsevier Inc. All rights reserved.

Scalable Method to Produce Biodegradable Nanoparticles that Rapidly Penetrate Human Mucus

PubMed Central

Xu, Qingguo; Boylan, Nicholas J.; Cai, Shutian; Miao, Bolong; Patel, Himatkumar; Hanes, Justin

2013-01-01

Mucus typically traps and rapidly removes foreign particles from the airways, gastrointestinal tract, nasopharynx, female reproductive tract and the surface of the eye. Nanoparticles capable of rapid penetration through mucus can potentially avoid rapid clearance, and open significant opportunities for controlled drug delivery at mucosal surfaces. Here, we report an industrially scalable emulsification method to produce biodegradable mucus-penetrating particles (MPP). The emulsification of diblock copolymers of poly(lactic-co-glycolic acid) and polyethylene glycol (PLGA-PEG) using low molecular weight (MW) emulsifiers forms dense brush PEG coatings on nanoparticles that allow rapid nanoparticle penetration through fresh undiluted human mucus. In comparison, conventional high MW emulsifiers, such as polyvinyl alcohol (PVA), interrupts the PEG coating on nanoparticles, resulting in their immobilization in mucus owing to adhesive interactions with mucus mesh elements. PLGA-PEG nanoparticles with a wide range of PEG MW (1, 2, 5, and 10 kDa), prepared by the emulsification method using low MW emulsifiers, all rapidly penetrated mucus. A range of drugs, from hydrophobic small molecules to hydrohilic large biologics, can be efficiently loaded into biodegradable MPP using the method described. This readily scalable method should facilitate the production of MPP products for mucosal drug delivery, as well as potentially longer-circulating particles following intravenous administration. PMID:23751567

A poly(ethylene glycol)-based surfactant for formulation of drug-loaded mucus penetrating particles

PubMed Central

Mert, Olcay; Lai, Samuel K.; Ensign, Laura; Yang, Ming; Wang, Ying-Ying; Wood, Joseph; Hanes, Justin

2011-01-01

Mucosal surfaces are protected by a highly viscoelastic and adhesive mucus layer that traps most foreign particles, including conventional drug and gene carriers. Trapped particles are eliminated on the order of seconds to hours by mucus clearance mechanisms, precluding sustained and targeted drug and nucleic acid delivery to mucosal tissues. We have previously shown that polymeric coatings that minimize adhesive interactions with mucus constituents lead to particles that rapidly penetrate human mucus secretions. Nevertheless, a particular challenge in formulating drug-loaded mucus penetrating particles (MPP) is that many commonly used surfactants are either mucoadhesive, or do not facilitate efficient drug encapsulation. We tested a novel surfactant molecule for particle formulation composed of Vitamin E conjugated to 5 kDa polyethylene glycol (VP5k). We show that VP5k-coated poly(lactide-co-glycolide) (PLGA) nanoparticles rapidly penetrate human cervicovaginal mucus, whereas PLGA nanoparticles coated with polyvinyl alcohol or Vitamin E conjugated to 1 kDa PEG were trapped. Importantly, VP5k facilitated high loading of paclitaxel, a frontline chemo drug, into PLGA MPP, with controlled release for at least 4 days and negligible burst release. Our results offer a promising new method for engineering biodegradable, drug-loaded MPP for sustained and targeted delivery of therapeutics at mucosal surfaces. PMID:21911015

Hybrid Molecular Structure of the Giant Protease Tripeptidyl Peptidase II

PubMed Central

Chuang, Crystal K.; Rockel, Beate; Seyit, Gönül; Walian, Peter J.; Schönegge, Anne–Marie; Peters, Jürgen; Zwart, Petrus H.; Baumeister, Wolfgang; Jap, Bing K.

2010-01-01

Tripeptidyl peptidase II (TPP II) is the largest known eukaryotic protease (6MDa). It is believed to act downstream of the 26S proteasome cleaving tripeptides from the N– termini of longer peptides and it is implicated in numerous cellular processes. Here we report the structure of Drosophila TPP II determined by a hybrid approach: The structure of the dimer was solved by x–ray crystallography and docked into the three– dimensional map of the holocomplex obtained by single-particle cryo-electron microscopy. The resulting structure reveals the compartmentalization of the active sites inside a system of chambers and suggests the existence of a molecular ruler determining the size of the cleavage products. Furthermore, the structure suggests a model for activation of TPP II involving the relocation of a flexible loop and a repositioning of the active–site serine, coupling it to holocomplex assembly and active site sequestration. PMID:20676100

A new family of cyanobacterial penicillin-binding proteins. A missing link in the evolution of class A beta-lactamases.

PubMed

Urbach, Carole; Fastrez, Jacques; Soumillion, Patrice

2008-11-21

It is largely accepted that serine beta-lactamases evolved from some ancestral DD-peptidases involved in the biosynthesis and maintenance of the bacterial peptidoglycan. DD-peptidases are also called penicillin-binding proteins (PBPs), since they form stable acyl-enzymes with beta-lactam antibiotics, such as penicillins. On the other hand, beta-lactamases react similarly with these antibiotics, but the acyl-enzymes are unstable and rapidly hydrolyzed. Besides, all known PBPs and beta-lactamases share very low sequence similarities, thus rendering it difficult to understand how a PBP could evolve into a beta-lactamase. In this study, we identified a new family of cyanobacterial PBPs featuring the highest sequence similarity with the most widespread class A beta-lactamases. Interestingly, the Omega-loop, which, in the beta-lactamases, carries an essential glutamate involved in the deacylation process, is six amino acids shorter and does not contain any glutamate residue. From this new family of proteins, we characterized PBP-A from Thermosynechococcus elongatus and discovered hydrolytic activity with synthetic thiolesters that are usually good substrates of DD-peptidases. Penicillin degradation pathways as well as acylation and deacylation rates are characteristic of PBPs. In a first attempt to generate beta-lactamase activity, a 90-fold increase in deacylation rate was obtained by introducing a glutamate in the shorter Omega-loop.

Bovine pancreatic trypsin inhibitor immobilized onto sepharose as a new strategy to purify a thermostable alkaline peptidase from cobia (Rachycentron canadum) processing waste.

PubMed

França, Renata Cristina da Penha; Assis, Caio Rodrigo Dias; Santos, Juliana Ferreira; Torquato, Ricardo José Soares; Tanaka, Aparecida Sadae; Hirata, Izaura Yoshico; Assis, Diego Magno; Juliano, Maria Aparecida; Cavalli, Ronaldo Olivera; Carvalho, Luiz Bezerra de; Bezerra, Ranilson Souza

2016-10-15

A thermostable alkaline peptidase was purified from the processing waste of cobia (Rachycentron canadum) using bovine pancreatic trypsin inhibitor (BPTI) immobilized onto Sepharose. The purified enzyme had an apparent molecular mass of 24kDa by both sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometry. Its optimal temperature and pH were 50°C and 8.5, respectively. The enzyme was thermostable until 55°C and its activity was strongly inhibited by the classic trypsin inhibitors N-ρ-tosyl-l-lysine chloromethyl ketone (TLCK) and benzamidine. BPTI column allowed at least 15 assays without loss of efficacy. The purified enzyme was identified as a trypsin and the N-terminal amino acid sequence of this trypsin was IVGGYECTPHSQAHQVSLNSGYHFC, which was highly homologous to trypsin from cold water fish species. Using Nα-benzoyl-dl-arginine ρ-nitroanilide hydrochloride (BApNA) as substrate, the apparent km value of the purified trypsin was 0.38mM, kcat value was 3.14s(-1), and kcat/km was 8.26s(-1)mM(-1). The catalytic proficiency of the purified enzyme was 2.75×10(12)M(-1) showing higher affinity for the substrate at the transition state than other fish trypsin. The activation energy (AE) of the BApNA hydrolysis catalyzed by this enzyme was estimated to be 11.93kcalmol(-1) while the resulting rate enhancement of this reaction was found to be approximately in a range from 10(9) to 10(10)-fold evidencing its efficiency in comparison to other trypsin. This new purification strategy showed to be appropriate to obtain an alkaline peptidase from cobia processing waste with high purification degree. According with N-terminal homology and kinetic parameters, R. canadum trypsin may gathers desirable properties of psychrophilic and thermostable enzymes. Copyright © 2016 Elsevier B.V. All rights reserved.

Navier-Stokes Aerodynamic Simulation of the V-22 Osprey on the Intel Paragon MPP

NASA Technical Reports Server (NTRS)

Vadyak, Joseph; Shrewsbury, George E.; Narramore, Jim C.; Montry, Gary; Holst, Terry; Kwak, Dochan (Technical Monitor)

1995-01-01

The paper will describe the Development of a general three-dimensional multiple grid zone Navier-Stokes flowfield simulation program (ENS3D-MPP) designed for efficient execution on the Intel Paragon Massively Parallel Processor (MPP) supercomputer, and the subsequent application of this method to the prediction of the viscous flowfield about the V-22 Osprey tiltrotor vehicle. The flowfield simulation code solves the thin Layer or full Navier-Stoke's equation - for viscous flow modeling, or the Euler equations for inviscid flow modeling on a structured multi-zone mesh. In the present paper only viscous simulations will be shown. The governing difference equations are solved using a time marching implicit approximate factorization method with either TVD upwind or central differencing used for the convective terms and central differencing used for the viscous diffusion terms. Steady state or Lime accurate solutions can be calculated. The present paper will focus on steady state applications, although time accurate solution analysis is the ultimate goal of this effort. Laminar viscosity is calculated using Sutherland's law and the Baldwin-Lomax two layer algebraic turbulence model is used to compute the eddy viscosity. The Simulation method uses an arbitrary block, curvilinear grid topology. An automatic grid adaption scheme is incorporated which concentrates grid points in high density gradient regions. A variety of user-specified boundary conditions are available. This paper will present the application of the scalable and superscalable versions to the steady state viscous flow analysis of the V-22 Osprey using a multiple zone global mesh. The mesh consists of a series of sheared cartesian grid blocks with polar grids embedded within to better simulate the wing tip mounted nacelle. MPP solutions will be shown in comparison to equivalent Cray C-90 results and also in comparison to experimental data. Discussions on meshing considerations, wall clock execution time, load balancing, and scalability will be provided.

Anorexia Nervosa: Analysis of Trabecular Texture with CT

PubMed Central

Tabari, Azadeh; Torriani, Martin; Miller, Karen K.; Klibanski, Anne; Kalra, Mannudeep K.

2017-01-01

Purpose To determine indexes of skeletal integrity by using computed tomographic (CT) trabecular texture analysis of the lumbar spine in patients with anorexia nervosa and normal-weight control subjects and to determine body composition predictors of trabecular texture. Materials and Methods This cross-sectional study was approved by the institutional review board and compliant with HIPAA. Written informed consent was obtained. The study included 30 women with anorexia nervosa (mean age ± standard deviation, 26 years ± 6) and 30 normal-weight age-matched women (control group). All participants underwent low-dose single-section quantitative CT of the L4 vertebral body with use of a calibration phantom. Trabecular texture analysis was performed by using software. Skewness (asymmetry of gray-level pixel distribution), kurtosis (pointiness of pixel distribution), entropy (inhomogeneity of pixel distribution), and mean value of positive pixels (MPP) were assessed. Bone mineral density and abdominal fat and paraspinal muscle areas were quantified with quantitative CT. Women with anorexia nervosa and normal-weight control subjects were compared by using the Student t test. Linear regression analyses were performed to determine associations between trabecular texture and body composition. Results Women with anorexia nervosa had higher skewness and kurtosis, lower MPP (P < .001), and a trend toward lower entropy (P = .07) compared with control subjects. Bone mineral density, abdominal fat area, and paraspinal muscle area were inversely associated with skewness and kurtosis and positively associated with MPP and entropy. Texture parameters, but not bone mineral density, were associated with lowest lifetime weight and duration of amenorrhea in anorexia nervosa. Conclusion Patients with anorexia nervosa had increased skewness and kurtosis and decreased entropy and MPP compared with normal-weight control subjects. These parameters were associated with lowest lifetime weight and duration of amenorrhea, but there were no such associations with bone mineral density. These findings suggest that trabecular texture analysis might contribute information about bone health in anorexia nervosa that is independent of that provided with bone mineral density. © RSNA, 2016 PMID:27797678

Live imaging of mitochondrial dynamics in CNS dopaminergic neurons in vivo demonstrates early reversal of mitochondrial transport following MPP+ exposure

PubMed Central

Dukes, April A.; Bai, Qing; Van Laar, Victor S.; Zhou, Yangzhong; Ilin, Vladimir; David, Christopher N.; Agim, Zeynep S.; Bonkowsky, Joshua L.; Cannon, Jason R.; Watkins, Simon C.; St. Croix, Claudette M.; Burton, Edward A.; Berman, Sarah B.

2016-01-01

Extensive convergent evidence collectively suggests that mitochondrial dysfunction is central to the pathogenesis of Parkinson’s disease (PD). Recently, changes in the dynamic properties of mitochondria have been increasingly implicated as a key proximate mechanism underlying neurodegeneration. However, studies have been limited by the lack of a model in which mitochondria can be imaged directly and dynamically in dopaminergic neurons of the intact vertebrate CNS. We generated transgenic zebrafish in which mitochondria of dopaminergic neurons are labeled with a fluorescent reporter, and optimized methods allowing direct intravital imaging of CNS dopaminergic axons and measurement of mitochondrial transport in vivo. The proportion of mitochondria undergoing axonal transport in dopaminergic neurons decreased overall during development between 2 days post-fertilization (dpf) and 5dpf, at which point the major period of growth and synaptogenesis of the relevant axonal projections is complete. Exposure to 0.5 – 1.0mM MPP+ between 4 – 5 dpf did not compromise zebrafish viability or cause detectable changes in the number or morphology of dopaminergic neurons, motor function or monoaminergic neurochemistry. However, 0.5mM MPP+ caused a 300% increase in retrograde mitochondrial transport and a 30% decrease in anterograde transport. In contrast, exposure to higher concentrations of MPP+ caused an overall reduction in mitochondrial transport. This is the first time mitochondrial transport has been observed directly in CNS dopaminergic neurons of a living vertebrate and quantified in a PD model in vivo. Our findings are compatible with a model in which damage at presynaptic dopaminergic terminals causes an early compensatory increase in retrograde transport of compromised mitochondria for degradation in the cell body. These data are important because manipulation of early pathogenic mechanisms might be a valid therapeutic approach to PD. The novel transgenic lines and methods we developed will be useful for future studies on mitochondrial dynamics in health and disease. PMID:27452482

Live imaging of mitochondrial dynamics in CNS dopaminergic neurons in vivo demonstrates early reversal of mitochondrial transport following MPP(+) exposure.

PubMed

Dukes, April A; Bai, Qing; Van Laar, Victor S; Zhou, Yangzhong; Ilin, Vladimir; David, Christopher N; Agim, Zeynep S; Bonkowsky, Joshua L; Cannon, Jason R; Watkins, Simon C; Croix, Claudette M St; Burton, Edward A; Berman, Sarah B

2016-11-01

Extensive convergent evidence collectively suggests that mitochondrial dysfunction is central to the pathogenesis of Parkinson's disease (PD). Recently, changes in the dynamic properties of mitochondria have been increasingly implicated as a key proximate mechanism underlying neurodegeneration. However, studies have been limited by the lack of a model in which mitochondria can be imaged directly and dynamically in dopaminergic neurons of the intact vertebrate CNS. We generated transgenic zebrafish in which mitochondria of dopaminergic neurons are labeled with a fluorescent reporter, and optimized methods allowing direct intravital imaging of CNS dopaminergic axons and measurement of mitochondrial transport in vivo. The proportion of mitochondria undergoing axonal transport in dopaminergic neurons decreased overall during development between 2days post-fertilization (dpf) and 5dpf, at which point the major period of growth and synaptogenesis of the relevant axonal projections is complete. Exposure to 0.5-1.0mM MPP(+) between 4 and 5dpf did not compromise zebrafish viability or cause detectable changes in the number or morphology of dopaminergic neurons, motor function or monoaminergic neurochemistry. However, 0.5mM MPP(+) caused a 300% increase in retrograde mitochondrial transport and a 30% decrease in anterograde transport. In contrast, exposure to higher concentrations of MPP(+) caused an overall reduction in mitochondrial transport. This is the first time mitochondrial transport has been observed directly in CNS dopaminergic neurons of a living vertebrate and quantified in a PD model in vivo. Our findings are compatible with a model in which damage at presynaptic dopaminergic terminals causes an early compensatory increase in retrograde transport of compromised mitochondria for degradation in the cell body. These data are important because manipulation of early pathogenic mechanisms might be a valid therapeutic approach to PD. The novel transgenic lines and methods we developed will be useful for future studies on mitochondrial dynamics in health and disease. Published by Elsevier Inc.

Δ⁹-tetrahydrocannabinol (Δ⁹-THC) exerts a direct neuroprotective effect in a human cell culture model of Parkinson's disease.

PubMed

Carroll, C B; Zeissler, M-L; Hanemann, C O; Zajicek, J P

2012-10-01

Δ⁹-tetrahydrocannabinol (Δ⁹-THC) is neuroprotective in models of Parkinson's disease (PD). Although CB1 receptors are increased within the basal ganglia of PD patients and animal models, current evidence suggests a role for CB1 receptor-independent mechanisms. Here, we utilized a human neuronal cell culture PD model to further investigate the protective properties of Δ⁹-THC. Differentiated SH-SY5Y neuroblastoma cells were exposed to PD-relevant toxins: 1-methyl-4-phenylpyridinium (MPP+), lactacystin and paraquat. Changes in CB1 receptor level were determined by quantitative polymerase chain reaction and Western blotting. Cannabinoids and modulatory compounds were co-administered with toxins for 48 h and the effects on cell death, viability, apoptosis and oxidative stress assessed. We found CB1 receptor up-regulation in response to MPP+, lactacystin and paraquat and a protective effect of Δ⁹-THC against all three toxins. This neuroprotective effect was not reproduced by the CB1 receptor agonist WIN55,212-2 or blocked by the CB1 antagonist AM251. Furthermore, the antioxidants α-tocopherol and butylhydroxytoluene as well as the antioxidant cannabinoids, nabilone and cannabidiol were unable to elicit the same neuroprotection as Δ⁹-THC. However, the peroxisome proliferator-activated receptor-gamma (PPARγ) antagonist T0070907 dose-dependently blocked the neuroprotective, antioxidant and anti-apoptotic effects of Δ⁹-THC, while the PPARγ agonist pioglitazone resulted in protection from MPP+-induced neurotoxicity. Furthermore, Δ⁹-THC increased PPARγ expression in MPP+-treated SH-SY5Y cells, another indicator of PPARγ activation. We have demonstrated up-regulation of the CB1 receptor in direct response to neuronal injury in a human PD cell culture model, and a direct neuronal protective effect of Δ⁹-THC that may be mediated through PPARγ activation. © 2011 The Authors. Neuropathology and Applied Neurobiology © 2011 British Neuropathological Society.

Effects of seasonal change and parity on raw milk composition and related indices in Chinese Holstein cows in northern China.

PubMed

Yang, L; Yang, Q; Yi, M; Pang, Z H; Xiong, B H

2013-01-01

This study was to investigate the effects of seasonal change and parity on milk composition and related indices, and to analyze the relationships among milk indices in Chinese Holstein cows from an intensive dairy farm in northern China. The 6,520 sets of complete Dairy Herd Improvement data were obtained and grouped by natural month and parity. The data included daily milk yield (DMY), milk solids percentage (MSP), milk fat percentage (MFP), milk protein percentage (MPP), milk lactose percentage (MLP), somatic cell count (SCC), somatic cell score (SCS), milk production loss (MPL), and fat-to-protein ratio (FPR). Data analysis showed that the above 9 indices were affected by both seasonal change and parity. However, the interaction between parity and seasonal change showed effects on MLP, SCS, MPL, and DMY, but no effects on MFP, MPP, MSP, and FPR. Duncan's multiple comparison on seasonal change showed that DMY (23.58 kg/d), MSP (12.35%), MPP (3.02%), and MFP (3.81%) were the lowest in June, but SCC (288.7 × 10(3)/mL) and MPL (0.69 kg/d) were the lowest in January; FPR (1.32) was the highest in February. Meanwhile, Duncan's multiple comparison on parities showed that MSP, MPP, and MLP were reduced rapidly in the fourth lactation, but SCC and MPL increased with increasing parities. The canonical correlation analysis for indices showed that SCS had high positive correlation with MPL (0.8360). Therefore, a few models were developed to quantify the effects of seasonal change and parity on raw milk composition using the Wood model. The changing patterns of milk composition and related indices in different months and parities could provide scientific evidence for improving feeding management and nutritional supplementation of Chinese Holstein cows. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Genetic variants of organic cation transporter 1 (OCT1) and OCT2 significantly reduce lamivudine uptake.

PubMed

Choi, Min-Koo; Song, Im-Sook

2012-04-01

The study sought to investigate the effect of genetic variants of OCT1 (OCT1-P283L and -P341L) and OCT2 (OCT2-T199I, -T201M and -A270S), which were identified in a Korean population, on the transport of lamivudine in vitro and to compare the substrate dependent effects of OCT1 and OCT2 variants with 1-methyl-4-phenylpyridinium (MPP+), tetraethyl ammonium (TEA), metformin and lamivudine as substrates for these transporters. When the transport kinetics of lamivudine uptake in oocytes overexpressing OCT1 and OCT2 wild-type (WT) and variant proteins were measured, lamivudine uptake mediated by OCT1-WT was saturable, and uptake was decreased in oocytes expressing OCT1-P283L and -P341L variants compared with that in OCT1-WT. The Clint of lamivudine in oocytes expressing OCT1-P283L was decreased by 85.1% compared with OCT1-WT, whereas it was decreased by 48.7% in oocytes expressing OCT1-P341L. The Clint of lamivudine in oocytes expressing OCT2-T199I, -T201M and -A270S was decreased by 86.2%, 88.9% and 73.6%, respectively, compared with OCT2-WT. When comparing various substrates such as MPP+, TEA, metformin and lamivudine, the effects of the OCT1 genetic polymorphisms on their uptake were not identical. However, contrary to the case of OCT1, the uptake of MPP+, TEA, metformin and lamivudine in oocytes expressing OCT2-T199I, -T201M and -A270S variants was decreased significantly compared with that in oocytes expressing OCT2-WT. In conclusion, the effect of genetic variations of OCT1 and OCT2 on the uptake of MPP+, TEA, metformin and lamivudine was substrate-dependent. Copyright © 2012 John Wiley & Sons, Ltd.

Ocean iron-fertilisation by volcanic ash

NASA Astrophysics Data System (ADS)

Langmann, B.; Zaksek, K.; Hort, M. K.; Duggen, S.

2009-12-01

Marine primary productivity (MPP) can be limited by the availability of macro-nutrients like nitrate and phosphate. In so-called ‘High-Nutrient-Low-Chlorophyll’ (HNLC) areas, macro-nutrient concentrations are high, but iron is the key biologically limiting micro-nutrient for primary production. Three major sources for iron supply into the ocean have been considered so far: upwelling of deep ocean water, advection from the continental margins and atmospheric deposition with aeolian dust deposition commonly assumed to dominate external iron supply to the open ocean. Iron supply to HNLC regions can affect climate relevant ocean-atmosphere exchanges of chemical trace species, e.g. organic carbon aerosols, DMS and CO2. Marine aerosols can act as efficient cloud condensation nuclei and significantly influence cloud properties and thus the Earth’s radiative budget via the indirect aerosol effects whereas a drawdown of atmospheric CO2 due to ocean fertilisation can have important implications for the global CO2 budget. Recent laboratory experiments suggest that material from volcanic eruptions such as ash may also affect the MPP through rapid iron-release on contact with seawater. Direct evidence, however, that volcanic activity can cause natural iron-fertilisation and MPP increase has been lacking so far. Here first evidence for a large-scale phytoplankton bloom in the NE Pacific resulting from volcanic ash fall after the eruption of Kasatochi volcano in August 2008 is presented. Atmospheric and oceanic conditions were favourable to generate this phytoplankton bloom. We present satellite observations to show the connection between volcanic ash fall and oceanic MPP. In addition, three-dimensional atmosphere/chemistry-aerosol model results are presented showing the atmospheric distribution of volcanic ash and its fall-out after the eruption of Kasatochi volcano. The amount of ash and that of iron attached to it is sufficient to explain measured seawater CO2 decrease at the ocean station Papa in August 2008 as well as the phytoplankton bloom in the Gulf of Alaska.

Amentoflavone protects dopaminergic neurons in MPTP-induced Parkinson's disease model mice through PI3K/Akt and ERK signaling pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Qin; Qin, Liyue; Huang, Fei, E-mail: Fei_H@ho

Parkinson's disease (PD) is characterized by the progressive degeneration of dopaminergic neurons in substantia nigra pars compacta (SNpc). Mitochondrial dysfunction and cell apoptosis are suggested to be actively involved in the pathogenesis of PD. In the present study, the neuroprotective effect of amentoflavone (AF), a naturally occurring biflavonoid from Selaginella tamariscina, was examined in PD models both in vitro and in vivo. On SH-SY5Y cells, AF treatment dose-dependently reduced 1-methyl-4-phenylpyridinium (MPP{sup +})-induced nuclear condensation and loss of cell viability without obvious cytotoxicity. It inhibited the activation of caspase-3 and p21 but increased the Bcl-2/Bax ratio. Further study disclosed that AFmore » enhanced the phosphorylation of PI3K, Akt and ERK1/2 down-regulated by MPP{sup +} in SH-SY5Y cells, the effect of which could be blocked by LY294002, the inhibitor of PI3K. Consistently, AF alleviated the behavioral deterioration in pole and traction tests and rescued the loss of dopaminergic neurons in SNpc and fibers in striatum in methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced mice. It also could enhance the activation of PI3K and Akt as well as Bcl-2/Bax ratio in SN. Moreover, AF alleviated gliosis as well as the gene expression levels of IL-1β and iNOS in SN. Collectively, these results suggested that AF protected dopaminergic neurons against MPTP/MPP{sup +}-induced neurotoxicity, which might be mediated through activation of PI3K/Akt and ERK signaling pathways in dopaminergic neurons and attenuation of neuroinflammation. - Highlights: • AF protected dopaminergic neurons against MPTP/MPP{sup +}-induced neurotoxicity. • AF modulated PI3K/Akt and ERK signaling pathways. • AF could alleviate neuroinflammation in SN.« less

Anorexia Nervosa: Analysis of Trabecular Texture with CT.

PubMed

Tabari, Azadeh; Torriani, Martin; Miller, Karen K; Klibanski, Anne; Kalra, Mannudeep K; Bredella, Miriam A

2017-04-01

Purpose To determine indexes of skeletal integrity by using computed tomographic (CT) trabecular texture analysis of the lumbar spine in patients with anorexia nervosa and normal-weight control subjects and to determine body composition predictors of trabecular texture. Materials and Methods This cross-sectional study was approved by the institutional review board and compliant with HIPAA. Written informed consent was obtained. The study included 30 women with anorexia nervosa (mean age ± standard deviation, 26 years ± 6) and 30 normal-weight age-matched women (control group). All participants underwent low-dose single-section quantitative CT of the L4 vertebral body with use of a calibration phantom. Trabecular texture analysis was performed by using software. Skewness (asymmetry of gray-level pixel distribution), kurtosis (pointiness of pixel distribution), entropy (inhomogeneity of pixel distribution), and mean value of positive pixels (MPP) were assessed. Bone mineral density and abdominal fat and paraspinal muscle areas were quantified with quantitative CT. Women with anorexia nervosa and normal-weight control subjects were compared by using the Student t test. Linear regression analyses were performed to determine associations between trabecular texture and body composition. Results Women with anorexia nervosa had higher skewness and kurtosis, lower MPP (P < .001), and a trend toward lower entropy (P = .07) compared with control subjects. Bone mineral density, abdominal fat area, and paraspinal muscle area were inversely associated with skewness and kurtosis and positively associated with MPP and entropy. Texture parameters, but not bone mineral density, were associated with lowest lifetime weight and duration of amenorrhea in anorexia nervosa. Conclusion Patients with anorexia nervosa had increased skewness and kurtosis and decreased entropy and MPP compared with normal-weight control subjects. These parameters were associated with lowest lifetime weight and duration of amenorrhea, but there were no such associations with bone mineral density. These findings suggest that trabecular texture analysis might contribute information about bone health in anorexia nervosa that is independent of that provided with bone mineral density. © RSNA, 2016.

Cell type-specific gene expression of midbrain dopaminergic neurons reveals molecules involved in their vulnerability and protection.

PubMed

Chung, Chee Yeun; Seo, Hyemyung; Sonntag, Kai Christian; Brooks, Andrew; Lin, Ling; Isacson, Ole

2005-07-01

Molecular differences between dopamine (DA) neurons may explain why the mesostriatal DA neurons in the A9 region preferentially degenerate in Parkinson's disease (PD) and toxic models, whereas the adjacent A10 region mesolimbic and mesocortical DA neurons are relatively spared. To characterize innate physiological differences between A9 and A10 DA neurons, we determined gene expression profiles in these neurons in the adult mouse by laser capture microdissection, microarray analysis and real-time PCR. We found 42 genes relatively elevated in A9 DA neurons, whereas 61 genes were elevated in A10 DA neurons [> 2-fold; false discovery rate (FDR) < 1%]. Genes of interest for further functional analysis were selected by criteria of (i) fold differences in gene expression, (ii) real-time PCR validation and (iii) potential roles in neurotoxic or protective biochemical pathways. Three A9-elevated molecules [G-protein coupled inwardly rectifying K channel 2 (GIRK2), adenine nucleotide translocator 2 (ANT-2) and the growth factor IGF-1] and three A10-elevated peptides (GRP, CGRP and PACAP) were further examined in both alpha-synuclein overexpressing PC12 (PC12-alphaSyn) cells and rat primary ventral mesencephalic (VM) cultures exposed to MPP+ neurotoxicity. GIRK2-positive DA neurons were more vulnerable to MPP+ toxicity and overexpression of GIRK2 increased the vulnerability of PC12-alphaSyn cells to the toxin. Blocking of ANT decreased vulnerability to MPP+ in both cell culture systems. Exposing cells to IGF-1, GRP and PACAP decreased vulnerability of both cell types to MPP+, whereas CGRP protected PC12-alphaSyn cells but not primary VM DA neurons. These results indicate that certain differentially expressed molecules in A9 and A10 DA neurons may play key roles in their relative vulnerability to toxins and PD.

Peptidases prevent mu-opioid receptor internalization in dorsal horn neurons by endogenously released opioids.

PubMed

Song, Bingbing; Marvizón, Juan Carlos G

2003-03-01

To evaluate the effect of peptidases on mu-opioid receptor (MOR) activation by endogenous opioids, we measured MOR-1 internalization in rat spinal cord slices. A mixture of inhibitors of aminopeptidases (amastatin), dipeptidyl carboxypeptidase (captopril), and neutral endopeptidase (phosphoramidon) dramatically increased the potencies of Leu-enkephalin and dynorphin A to produce MOR-1 internalization, and also enhanced the effects of Met-enkephalin and alpha-neoendorphin, but not endomorphins or beta-endorphin. The omission of any one inhibitor abolished Leu-enkephalin-induced internalization, indicating that all three peptidases degraded enkephalins. Amastatin preserved dynorphin A-induced internalization, and phosphoramidon, but not captopril, increased this effect, indicating that the effect of dynorphin A was prevented by aminopeptidases and neutral endopeptidase. Veratridine (30 microm) or 50 mm KCl produced MOR-1 internalization in the presence of peptidase inhibitors, but little or no internalization in their absence. These effects were attributed to opioid release, because they were abolished by the selective MOR antagonist CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2)) and were Ca(2+) dependent. The effect of veratridine was protected by phosphoramidon plus amastatin or captopril, but not by amastatin plus captopril or by phosphoramidon alone, indicating that released opioids are primarily cleaved by neutral endopeptidase, with a lesser involvement of aminopeptidases and dipeptidyl carboxypeptidase. Therefore, because the potencies of endomorphin-1 and endomorphin-2 to elicit internalization were unaffected by peptidase inhibitors, the opioids released by veratridine were not endomorphins. Confocal microscopy revealed that MOR-1-expressing neurons were in close proximity to terminals containing opioids with enkephalin-like sequences. These findings indicate that peptidases prevent the activation of extrasynaptic MOR-1 in dorsal horn neurons.

Peptidases prevent μ-opioid receptor internalization in dorsal horn neurons by endogenously released opioids

PubMed Central

Song, Bingbing; Marvizón, Juan Carlos G.

2008-01-01

To evaluate the effect of peptidases on μ-opioid receptor (MOR) activation by endogenous opioids, we measured MOR-1 internalization in rat spinal cord slices. A mixture of inhibitors of aminopeptidases (amastatin), dipeptidyl carboxypeptidase (captopril), and neutral endopeptidase (phosphoramidon) dramatically increased the potencies of Leu-enkephalin and dynorphin A to produce MOR-1 internalization, and also enhanced the effects of Met-enkephalin and α-neoendorphin, but not endomorphins or β-endorphin. Omission of any one inhibitor abolished Leu-enkephalin-induced internalization, indicating that all three peptidases degraded enkephalins. Amastatin preserved dynorphin A-induced internalization, and phosphoramidon, but not captopril, increased this effect, indicating that the effect of dynorphin A was prevented by aminopeptidases and neutral endopeptidase. Veratridine (30 μM) or 50 mM KCl produced MOR-1 internalization in the presence of peptidase inhibitors, but little or no internalization in their absence. These effects were attributed to opioid release, because they were abolished by the selective MOR antagonist CTAP and were Ca2+-dependent. The effect of veratridine was protected by phosphoramidon plus amastatin or captopril, but not by amastatin plus captopril or by phosphoramidon alone, indicating that released opioids are mainly cleaved by neutral endopeptidase, with a lesser involvement of aminopeptidases and dipeptidyl carboxypeptidase. Therefore, since the potencies of endomorphin-1 and -2 to elicit internalization were unaffected by peptidase inhibitors, the opioids released by veratridine were not endomorphins. Confocal microscopy revealed that MOR-1-expressing neurons were in close proximity to terminals containing opioids with enkephalin-like sequences. These findings indicate that peptidases prevent the activation of extrasynaptic MOR-1 in dorsal horn neurons. PMID:12629189

Inhibition of dipeptidyl-peptidase IV catalyzed peptide truncation by Vildagliptin ((2S)-{[(3-hydroxyadamantan-1-yl)amino]acetyl}-pyrrolidine-2-carbonitrile).

PubMed

Brandt, Inger; Joossens, Jurgen; Chen, Xin; Maes, Marie-Berthe; Scharpé, Simon; De Meester, Ingrid; Lambeir, Anne-Marie

2005-07-01

Vildagliptin (NVP-LAF237/(2S)-{[(3-hydroxyadamantan-1-yl)amino]acetyl}-pyrrolidine-2-carbonitrile) was described as a potent, selective and orally bio-available dipeptidyl-peptidase IV (DPP IV, EC 3.4.14.5) inhibitor [Villhauer EB, Brinkman JA, Naderi GB, Burkey BF, Dunning BE, Prasad K, et al.1-[[(3-Hydroxy-1-adamantyl)amino]acetyl]-2-cyano-(S)-pyrrolidine: a potent, selective, and orally bioavailable dipeptidyl peptidase IV inhibitor with antihyperglycemic properties. J Med Chem 2003;46:2774-89]. Phase III clinical trials for the use of this compound in the treatment of Type 2 diabetes were started in the first quarter of 2004. In this paper, we report on (1) the kinetics of binding, (2) the type of inhibition, (3) the selectivity with respect to other peptidases, and (4) the inhibitory potency on the DPP IV catalyzed degradation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and substance P. Vildagliptin behaved as a slow-binding DPP IV inhibitor with an association rate constant of 1.4x10(5)M(-1)s(-1) and a K(i) of 17nM. It is a micromolar inhibitor for dipeptidyl-peptidase 8 and does not significantly inhibit dipeptidyl-peptidase II (EC 3.4.11.2), prolyl oligopeptidase (EC 3.4.21.26), aminopeptidase P (EC 3.4.11.9) or aminopeptidase M (EC 3.4.11.2). There was no evidence for substrate specific inhibition of DPP IV by Vildagliptin or for important allosteric factors affecting the inhibition constant in presence of GIP and GLP-1.

Interactive hemodynamic effects of dipeptidyl peptidase-IV inhibition and angiotensin-converting enzyme inhibition in humans.

PubMed

Marney, Annis; Kunchakarra, Siri; Byrne, Loretta; Brown, Nancy J

2010-10-01

Dipeptidyl peptidase-IV inhibitors improve glucose homeostasis in type 2 diabetics by inhibiting degradation of the incretin hormones. Dipeptidyl peptidase-IV inhibition also prevents the breakdown of the vasoconstrictor neuropeptide Y and, when angiotensin-converting enzyme (ACE) is inhibited, substance P. This study tested the hypothesis that dipeptidyl peptidase-IV inhibition would enhance the blood pressure response to acute ACE inhibition. Subjects with the metabolic syndrome were treated with 0 mg of enalapril (n=9), 5 mg of enalapril (n=8), or 10 mg enalapril (n=7) after treatment with sitagliptin (100 mg/day for 5 days and matching placebo for 5 days) in a randomized, cross-over fashion. Sitagliptin decreased serum dipeptidyl peptidase-IV activity (13.08±1.45 versus 30.28±1.76 nmol/mL/min during placebo; P≤0.001) and fasting blood glucose. Enalapril decreased ACE activity in a dose-dependent manner (P<0.001). Sitagliptin lowered blood pressure during enalapril (0 mg; P=0.02) and augmented the hypotensive response to 5 mg of enalapril (P=0.05). In contrast, sitagliptin attenuated the hypotensive response to 10 mg of enalapril (P=0.02). During sitagliptin, but not during placebo, 10 mg of enalapril significantly increased heart rate and plasma norepinephrine concentrations. There was no effect of 0 or 5 mg of enalapril on heart rate or norepinephrine after treatment with either sitagliptin or placebo. Sitagliptin enhanced the dose-dependent effect of enalapril on renal blood flow. In summary, sitagliptin lowers blood pressure during placebo or submaximal ACE inhibition; sitagliptin activates the sympathetic nervous system to diminish hypotension when ACE is maximally inhibited. This study provides the first evidence for an interactive hemodynamic effect of dipeptidyl peptidase-IV and ACE inhibition in humans.

Characterization of a New M13 Metallopeptidase from Deep-Sea Shewanella sp. E525-6 and Mechanistic Insight into Its Catalysis

PubMed Central

Yang, Jin-Yu; Wang, Peng; Li, Chun-Yang; Dong, Sheng; Song, Xiao-Yan; Zhang, Xi-Ying; Xie, Bin-Bin; Zhou, Bai-Cheng; Zhang, Yu-Zhong; Chen, Xiu-Lan

2016-01-01

Bacterial extracellular peptidases are important for bacterial nutrition and organic nitrogen degradation in the ocean. While many peptidases of the M13 family from terrestrial animals and bacteria are studied, there has been no report on M13 peptidases from marine bacteria. Here, we characterized an M13 peptidase, PepS, from the deep-sea sedimentary strain Shewanella sp. E525-6, and investigated its substrate specificity and catalytic mechanism. The gene pepS cloned from strain E525-6 contains 2085 bp and encodes an M13 metallopeptidase. PepS was expressed in Escherichia coli and purified. Among the characterized M13 peptidases, PepS shares the highest sequence identity (47%) with Zmp1 from Mycobacterium tuberculosis, indicating that PepS is a new member of the M13 family. PepS had the highest activity at 30°C and pH 8.0. It retained 15% activity at 0°C. Its half life at 40°C was only 4 min. These properties indicate that PepS is a cold-adapted enzyme. The smallest substrate for PepS is pentapeptide, and it is probably unable to cleave peptides of more than 30 residues. PepS prefers to hydrolyze peptide bonds with P1′ hydrophobic residues. Structural and mutational analyses suggested that His531, His535 and Glu592 coordinate the catalytic zinc ion in PepS, Glu532 acts as a nucleophile, and His654 is probably involved in the transition state stabilization. Asp538 and Asp596 can stablize the orientations of His531 and His535, and Arg660 can stablize the orientation of Asp596. These results help in understanding marine bacterial peptidases and organic nitrogen degradation. PMID:26779153

Characterization of a New M13 Metallopeptidase from Deep-Sea Shewanella sp. E525-6 and Mechanistic Insight into Its Catalysis.

PubMed

Yang, Jin-Yu; Wang, Peng; Li, Chun-Yang; Dong, Sheng; Song, Xiao-Yan; Zhang, Xi-Ying; Xie, Bin-Bin; Zhou, Bai-Cheng; Zhang, Yu-Zhong; Chen, Xiu-Lan

2015-01-01

Bacterial extracellular peptidases are important for bacterial nutrition and organic nitrogen degradation in the ocean. While many peptidases of the M13 family from terrestrial animals and bacteria are studied, there has been no report on M13 peptidases from marine bacteria. Here, we characterized an M13 peptidase, PepS, from the deep-sea sedimentary strain Shewanella sp. E525-6, and investigated its substrate specificity and catalytic mechanism. The gene pepS cloned from strain E525-6 contains 2085 bp and encodes an M13 metallopeptidase. PepS was expressed in Escherichia coli and purified. Among the characterized M13 peptidases, PepS shares the highest sequence identity (47%) with Zmp1 from Mycobacterium tuberculosis, indicating that PepS is a new member of the M13 family. PepS had the highest activity at 30°C and pH 8.0. It retained 15% activity at 0°C. Its half life at 40°C was only 4 min. These properties indicate that PepS is a cold-adapted enzyme. The smallest substrate for PepS is pentapeptide, and it is probably unable to cleave peptides of more than 30 residues. PepS prefers to hydrolyze peptide bonds with P1' hydrophobic residues. Structural and mutational analyses suggested that His531, His535 and Glu592 coordinate the catalytic zinc ion in PepS, Glu532 acts as a nucleophile, and His654 is probably involved in the transition state stabilization. Asp538 and Asp596 can stablize the orientations of His531 and His535, and Arg660 can stablize the orientation of Asp596. These results help in understanding marine bacterial peptidases and organic nitrogen degradation.

Synthesis and Characterization of Atomically Precise Copper Nanoclusters

NASA Astrophysics Data System (ADS)

Nguyen, Thuy-Ai Dang

The reactivity of MCl3(eta1-TEMPO) (M = Fe, Al; TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) with a variety of lignin models, including 3,4-dimethoxybenzyl alcohol, 1-phenyl-2-phenoxyethanol and 1,2-diphenyl-2-methoxyethanol is investigated. FeCl3(TEMPO) is effective in cleanly converting these substrates to the corresponding aldehyde or ketone. AlCl3(eta1-TEMPO) is also able to oxidize these substrates, however in a few instances the products of over-oxidation are also observed. In contrast, 2-phenoxyethanol is not oxidized by MCl 3(eta1-TEMPO); instead it likely coordinates to the metal center, forming a 2-phenoxyethoxide complex. Oxidation of activated alkanes by MCl3(eta1-TEMPO) suggests that the reactions proceed via an initial 1-electron concerted proton-electron transfer (CPET) event. Finally, reaction of TEMPO with FeBr3 in Et 2O results in oxidation of the solvent. The copper hydride clusters [Cu14H12(phen) 6(PPh3)4][X]2 (X = Cl, OTf) are obtained in good yields by reaction of [(Ph3P)CuH]6 with 1,10-phenanthroline, in the presence of a halide or pseudohalide source. [Cu14H 12(phen)6(PPh3)4][Cl]2 reacts with CO2 in CH2Cl2, in the presence of excess Ph3P, to form the formate complex, [(Ph3P)2Cu(kappa 2-O2CH)], along with [(phen)(Ph3P)CuCl]. [Cu25H22(PPh3)12]Cl and [Cu 18H17(PPh3)10]Cl, are isolated from the reaction of Cu(OAc) and CuCl with Ph2SiH2, in the presence of PPh3. [Cu25H22(PPh3) 12]Cl formally features partial Cu(0) character. Subsequent reaction with Ph2phen resulted in the isolation of [Cu29Cl 4H22(Ph2phen)12]Cl (Ph2phen = 4,7-diphenyl-1,10-phenanthroline), in good yields. A time-resolved kinetic evaluation of the formation of [Cu29Cl4H22(Ph 2phen)12]Cl reveals that the mechanism of cluster growth is initiated by rapid ligand exchange, followed by slower extrusion of CuCl monomer, transport, and subsequent capture by intact clusters. Two Cu26 nanoclusters, tentatively formulated as [Cu 26H17(PPh3)9(OAc)3] and [Cu26H22(PPh3)10(OAc)2], are isolated from the reaction of Cu(OAc) with Ph2SiH2, in the presence of PPh3. As formulated, [Cu26H 17(PPh3)9(OAc)3] features a magic number N* = 6, which is unprecedented for a copper nanocluster. XANES supports an assignment of more Cu(0) character than [Cu25H 22(PPh3)12]Cl (N* = 2) for this complex. A critical reevaluation of the synthesis and characterization of Cu 8(MPP)4 is reported. This product was reportedly formed by reaction of Cu(NO3)2 with 2-mercapto-5-n-propylpyrimidine (HMPP) and NaBH4, in ethanol, in the presence of [N(C8H 17)4][Br]. However, upon reevaluation, no experimental evidence to support the existence of Cu8(MPP)4 was found. Instead, the material isolated from this reaction is a complex mixture containing [N(C8H17)4]+, Br -, NO3-, 2-mercapto-5-n-propyl-1,6-dihydropyrimidine (H2MPP*), along with the Cu(I) coordination polymer, [Cu(MPP)]n. H2MPP* and [Cu(MPP)]n, as well as the related Cu(I) coordination complexes, [Cu(HMPP*)]n and [Cu2(MPP*)]n are independently synthesized to support these conclusions.

Trypsin-like Proteins of the Fungi as Possible Markers of Phytopathogenicity

USDA-ARS?s Scientific Manuscript database

Sequences of peptidases with conserved motifs around the active site residues that are characteristic of trypsins (similar to trypsin peptidases, STP) were obtained from publicly available fungal genomes and related databases. Among the 74 fungal genomes, 30 species of parasitic Ascomycota contained...

Isolation and purification of Bacillus thuringiensis var. israelensis IМV В-7465 peptidase with specificity toward elastin and collagen.

PubMed

Nidialkova, N A; Varbanets, L D; Chernyshenko, V O

2016-01-01

Peptidase of Bacillus thuringiensis var. israelensis IМV В-7465 was isolated from culture supernatant using consecutive fractionations by an ammonium sulphate (60% saturation), ion-exchange chromatography and gel-filtration on the TSK-gels Toyoperl HW-55 and DEAE 650(M). Specific elastase (442 U∙mg of protein-1) and collagenase (212.7 U∙mg of protein-1) activities of the purified enzyme preparation were 8.0- and 6.1-fold, respectively higher than ones of the culture supernatant. Peptidase yields were 33.5% for elastase activity and 30.1% for collagenase activity. It was established that the enzyme is serine metal-dependent alkaline peptidase with Mr about 37 kDa. Maximal hydrolysis of elastin and collagen occurs at the optimum pH 8.0 and t° – 40 and 50 °С, respectively. The purified preparation has high stability at pH in the range of 7.0 to 10.0 and 40-50 °С.

Analysis of the proteolysis of bioactive peptides using a peptidomics approach

PubMed Central

Kim, Yun-Gon; Lone, Anna Mari; Saghatelian, Alan

2014-01-01

Identifying the peptidases that inactivate bioactive peptides (e.g. peptide hormones and neuropeptides) in mammals is an important unmet challenge. This protocol describes a recent approach that combines liquid chromatography-mass spectrometry peptidomics to identify endogenous cleavage sites of a bioactive peptide, the subsequent biochemical purification of a candidate peptidase based on these cleavage sites, and validation of the candidate peptidase’s role in the physiological regulation of the bioactive peptide by examining a peptidase knockout mouse. We highlight successful application of this protocol to discover that insulin-degrading enzyme (IDE) regulates physiological calcitonin gene-related peptide (CGRP) levels and detail the key stages and steps in this approach. This protocol requires 7 days of work; however, the total time for this protocol is highly variable because of its dependence on the availability of biological reagents, namely purified enzymes and knockout mice. The protocol is valuable because it expedites the characterization of mammalian peptidases, such as IDE, which in certain instances can be used to develop novel therapeutics. PMID:23949379

Crystallization and preliminary crystallographic analysis of porcine acylaminoacyl peptidase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, Helena; Kiss, András L.; Szeltner, Zoltán

2005-10-01

Acylaminoacyl peptidase from porcine liver has been crystallized. Data were collected to 3.4 Å from native crystals and a search for heavy-atom derivatives is in progress. Acylaminoacyl peptidase (also known as acylamino-acid-releasing enzyme or acylpeptide hydrolase; EC 3.4.19.1) is an unusual member of the prolyl oligopeptidase family catalysing the hydrolysis of an N-acylated peptide to an acylamino acid and a peptide with a free N-terminus. Acylaminoacyl peptidase purified from porcine liver has been crystallized in mother liquor containing 0.1 M Tris–HCl pH 7.0, 10%(w/v) polyethylene glycol 8000, 50 mM MgCl{sub 2} and 1%(w/v) CHAPS using the hanging-drop vapour-diffusion technique. Amore » full data set to 3.4 Å resolution was collected at ESRF beamline ID14-4 and space group C222 was assigned, with unit-cell parameters a = 84.8, b = 421.1, c = 212.0 Å and four molecules in the asymmetric unit.« less

In vitro degradation of neurotensin in human plasma.

PubMed

Lee, Y C; Uttenthal, L O; Smith, H A; Bloom, S R

1986-01-01

To study the degradation of neurotensin in plasma in vitro, fresh human plasma was incubated with neurotensin in the presence and absence of the peptidase inhibitors pepstatin A, EDTA, PMSF and aprotinin. The half-time of disappearance of neurotensin at 37 degrees C was calculated to be 226 min in vitro as opposed to 1.4 min in vivo when measured by radioimmunoassay with a C-terminally directed neurotensin antiserum. Both gel filtration and reversed phase high-pressure liquid chromatography (HPLC) showed that the main degradation product of neurotensin in human plasma in vitro was chromatographically and immunologically identical to neurotensin 1-8 and HPLC also demonstrated the formation of neurotensin 1-11. The loss of neurotensin incubated in human plasma in vitro was greatly reduced by EDTA but not by the other peptidase inhibitors tested. In this respect peptidase(s) responsible for the degradation of neurotensin in plasma differ from those present in brain homogenates. EDTA may be of importance in the preservation of neurotensin in plasma samples.

Dipeptidyl peptidase-4 inhibitors and incidence of inflammatory bowel disease among patients with type 2 diabetes: population based cohort study

PubMed Central

Abrahami, Devin; Douros, Antonios; Yin, Hui; Yu, Oriana Hoi Yun; Renoux, Christel; Bitton, Alain

2018-01-01

Abstract Objective To assess whether the use of dipeptidyl peptidase-4 inhibitors is associated with the incidence of inflammatory bowel disease in patients with type 2 diabetes. Design Population based cohort study. Setting More than 700 general practices contributing data to the United Kingdom Clinical Practice Research Datalink. Participants A cohort of 141 170 patients, at least 18 years of age, starting antidiabetic drugs between 1 January 2007 and 31 December 2016, with follow-up until 30 June 2017. Main outcome measures Adjusted hazard ratios for incident inflammatory bowel disease associated with use of dipeptidyl peptidase-4 inhibitors overall, by cumulative duration of use, and by time since initiation, estimated using time dependent Cox proportional hazards models. Use of dipeptidyl peptidase-4 inhibitors was modelled as a time varying variable and compared with use of other antidiabetic drugs, with exposures lagged by six months to account for latency and diagnostic delays. Results During 552 413 person years of follow-up, 208 incident inflammatory bowel disease events occurred (crude incidence rate of 37.7 (95% confidence interval 32.7 to 43.1) per 100 000 person years). Overall, use of dipeptidyl peptidase-4 inhibitors was associated with an increased risk of inflammatory bowel disease (53.4 v 34.5 per 100 000 person years; hazard ratio 1.75, 95% confidence interval 1.22 to 2.49). Hazard ratios gradually increased with longer durations of use, reaching a peak after three to four years of use (hazard ratio 2.90, 1.31 to 6.41) and decreasing after more than four years of use (1.45, 0.44 to 4.76). A similar pattern was observed with time since starting dipeptidyl peptidase-4 inhibitors. These findings remained consistent in several sensitivity analyses. Conclusions In this first population based study, the use of dipeptidyl peptidase-4 inhibitors was associated with an increased risk of inflammatory bowel disease. Although these findings need to be replicated, physicians should be aware of this possible association. PMID:29563098

Involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters in neonatal rat spinal cord.

PubMed

Suzuki, H; Yoshioka, K; Yanagisawa, M; Urayama, O; Kurihara, T; Hosoki, R; Saito, K; Otsuka, M

1994-09-01

1. The possible involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters was examined in the spinal cord of the neonatal rat. 2. The magnitude of substance P (SP)- or neurokinin A (NKA)-evoked depolarization of a lumbar ventral root in the isolated spinal cord preparation was increased by a mixture of peptidase inhibitors, consisting of actinonin (6 microM), arphamenine B (6 microM), bestatin (10 microM), captopril (10 microM) and thiorphan (0.3 microM). The mixture augmented the response to NKA more markedly than that to SP. 3. In the isolated spinal cord-cutaneous nerve preparation, the saphenous nerve-evoked slow depolarization of the L3 ventral root was augmented by the mixture of peptidase inhibitors in the presence of naloxone (0.5 microM) but not in the presence of both naloxone and a tachykinin receptor antagonist, GR71251 (5 microM). 4. Application of capsaicin (0.5 microM) for 6 min to the spinal cord evoked an increase in the release of SP from the spinal cord. The amount of SP released was significantly augmented by the mixture of peptidase inhibitors. 5. Synaptic membrane fractions were prepared from neonatal rat spinal cords. These fractions showed degrading activities for SP and NKA and the activities were inhibited by the mixture of peptidase inhibitors. The degrading activity for NKA was higher than that for SP and the inhibitory effect of the mixture for NKA was more marked than that for SP. Although some other fractions obtained from homogenates of spinal cords showed higher degrading activities for SP, these activities were insensitive to the mixture of peptidase inhibitors. 6. Effects of individual peptidase inhibitors on the enzymatic degradation of SP and NKA by synaptic membrane fractions were examined. Thiorphan, actinonin and captopril inhibited SP degradation, while thiorphan and actinonin, but not captopril, inhibited NKA degradation. The potency of the inhibition of each peptidase inhibitor was lower than that of the mixture.7. The present results suggest that enzymatic degradation is involved in the inactivation of tachykinin neurotransmitters in the spinal cord of the neonatal rat.

Proteomic identification of Drosophila melanogaster male accessory gland proteins, including a pro-cathepsin and a soluble gamma-glutamyl transpeptidase.

PubMed

Walker, Michael J; Rylett, Caroline M; Keen, Jeff N; Audsley, Neil; Sajid, Mohammed; Shirras, Alan D; Isaac, R Elwyn

2006-05-02

In Drosophila melanogaster, the male seminal fluid contains proteins that are important for reproductive success. Many of these proteins are synthesised by the male accessory glands and are secreted into the accessory gland lumen, where they are stored until required. Previous studies on the identification of Drosophila accessory gland products have largely focused on characterisation of male-specific accessory gland cDNAs from D. melanogaster and, more recently, Drosophila simulans. In the present study, we have used a proteomics approach without any sex bias to identify proteins in D. melanogaster accessory gland secretions. Thirteen secreted accessory gland proteins, including seven new accessory gland proteins, were identified by 2D-gel electrophoresis combined with mass spectrometry of tryptic fragments. They included protein-folding and stress-response proteins, a hormone, a lipase, a serpin, a cysteine-rich protein and two peptidases, a pro-enzyme form of a cathepsin K-like cysteine peptidase and a gamma-glutamyl transpeptidase. Enzymatic studies established that accessory gland secretions contain a cysteine peptidase zymogen that can be activated at low pH. This peptidase may have a role in the processing of female and other male-derived proteins, but is unlikely to be involved in the processing of the sex peptide. gamma-Glutamyl transpeptidases are type II integral membrane proteins; however, the identified AG gamma-glutamyl transpeptidase (GGT-1) is unusual in that it is predicted to be a soluble secreted protein, a prediction that is supported by biochemical evidence. GGT-1 is possibly involved in maintaining a protective redox environment for sperm. The strong gamma-glutamyl transpeptidase activity found in the secretions provides an explanation for the observation that glutamic acid is the most abundant free amino acid in accessory gland secretions of D. melanogaster. We have applied biochemical approaches, not used previously, to characterise prominent D. melanogaster accessory gland products. Of the thirteen accessory gland secreted proteins reported in this study, six were represented in a D. simulans male accessory gland EST library that was biased for male-specific genes. Therefore, the present study has identified seven new secreted accessory gland proteins, including GGT-1, which was not recognised previously as a secreted accessory gland product.

Use of a dehydroalanine-containing peptide as an efficient inhibitor of tripeptidyl peptidase II.

PubMed

Tomkinson, B; Grehn, L; Fransson, B; Zetterqvist, O

1994-11-01

Tripeptidyl peptidase II is an intracellular exopeptidase, which has been purified from rat liver and human erythrocytes. An efficient specific inhibitor was obtained through beta-elimination of phosphate from the phosphopeptide Arg-Ala-Ser(P)-Val-Ala. The dehydroalanine-containing peptide formed was a competitive inhibitor with a Ki of 0.02 +/- 0.01 microM. This study demonstrated that replacing a serine residue in a good inhibitor with a dehydroalanine residue reduced the Ki 45 times. It is proposed that dehydroalanine-containing peptides could be of interest in the development of inhibitors for other peptidases as well.

Real time animation of space plasma phenomena

NASA Technical Reports Server (NTRS)

Jordan, K. F.; Greenstadt, E. W.

1987-01-01

In pursuit of real time animation of computer simulated space plasma phenomena, the code was rewritten for the Massively Parallel Processor (MPP). The program creates a dynamic representation of the global bowshock which is based on actual spacecraft data and designed for three dimensional graphic output. This output consists of time slice sequences which make up the frames of the animation. With the MPP, 16384, 512 or 4 frames can be calculated simultaneously depending upon which characteristic is being computed. The run time was greatly reduced which promotes the rapid sequence of images and makes real time animation a foreseeable goal. The addition of more complex phenomenology in the constructed computer images is now possible and work proceeds to generate these images.

Drill/borescope System for the Mars Polar Pathfinder

NASA Technical Reports Server (NTRS)

Paige, D. A.; Wood, S. E.; Vasavada, A. R.

1993-01-01

The primary goals of the Mars Polar Pathfinder (MPP) Discovery Mission are to characterize the composition and structure of Mars' north polar ice cap, and to determine whether a climate record may be preserved in layers of ice and dust. The MPP would land as close as possible to the geographic north pole of Mars and use a set of instruments similar to those used by glaciologists to study polar ice caps on Earth: a radar sounder, a drill/borescope system, and a thermal probe. The drill/borescope system will drill approximately 50 cm into the surface and image the sides of the hole at 10 micron resolution for compositional and stratigraphic analysis. Several uncertainties have guided the development of this instrument, and they are discussed.

Methamphetamine protects against MPTP neurotoxicity in C57BL mice.

PubMed

Sziráki, I; Kardos, V; Patthy, M; Pátfalusi, M; Budai, G

1994-01-14

Methamphetamine (5 mg/kg) administered 30 min prior to each injection with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (3 x 30 mg/kg, at 24 h intervals) prevents the reduction of striatal levels of dopamine and its metabolites in C57BL mice. Methamphetamine and amphetamine inhibit the uptake of 1-methyl-4-phenylpyridinium (MPP+) by striatal synaptosomes of rats. A 30-min post-treatment with methamphetamine or amphetamine also prevents the MPTP-induced dopamine depletion, suggesting that their protective effect is related to the blockade of MPP+ uptake into dopaminergic neurons. Since amphetamine and methamphetamine are themselves neurotoxins at higher doses, this work demonstrated the protection against the actions of one neurotoxin by the administration of another.

Potential Activities of Freshwater Exo- and Endo-Acting Extracellular Peptidases in East Tennessee and the Pocono Mountains.

PubMed

Mullen, Lauren; Boerrigter, Kim; Ferriero, Nicholas; Rosalsky, Jeff; Barrett, Abigail van Buren; Murray, Patrick J; Steen, Andrew D

2018-01-01

Proteins constitute a particularly bioavailable subset of organic carbon and nitrogen in aquatic environments but must be hydrolyzed by extracellular enzymes prior to being metabolized by microorganisms. Activities of extracellular peptidases (protein-degrading enzymes) have frequently been assayed in freshwater systems, but such studies have been limited to substrates for a single enzyme [leucyl aminopeptidase (Leu-AP)] out of more than 300 biochemically recognized peptidases. Here, we report kinetic measurements of extracellular hydrolysis of five substrates in 28 freshwater bodies in the Delaware Water Gap National Recreation Area in the Pocono Mountains (PA, United States) and near Knoxville (TN, United States), between 2013 and 2016. The assays putatively test for four aminopeptidases (arginyl aminopeptidase, glyclyl aminopeptidase, Leu-AP, and pyroglutamyl aminopeptidase), which cleave N -terminal amino acids from proteins, and trypsin, an endopeptidase, which cleaves proteins mid-chain. Aminopeptidase and the trypsin-like activity were observed in all water bodies, indicating that a diverse set of peptidases is typical in freshwater. However, ratios of peptidase activities were variable among sites: aminopeptidases dominated at some sites and trypsin-like activity at others. At a given site, the ratios remained fairly consistent over time, indicating that they are driven by ecological factors. Studies in which only Leu-AP activity is measured may underestimate the total peptidolytic capacity of an environment, due to the variable contribution of endopeptidases.

Complementary Proteomic and Biochemical Analysis of Peptidases in Lobster Gastric Juice Uncovers the Functional Role of Individual Enzymes in Food Digestion.

PubMed

Bibo-Verdugo, Betsaida; O'Donoghue, Anthony J; Rojo-Arreola, Liliana; Craik, Charles S; García-Carreño, Fernando

2016-04-01

Crustaceans are a diverse group, distributed in widely variable environmental conditions for which they show an equally extensive range of biochemical adaptations. Some digestive enzymes have been studied by purification/characterization approaches. However, global analysis is crucial to understand how digestive enzymes interplay. Here, we present the first proteomic analysis of the digestive fluid from a crustacean (Homarus americanus) and identify glycosidases and peptidases as the most abundant classes of hydrolytic enzymes. The digestion pathway of complex carbohydrates was predicted by comparing the lobster enzymes to similar enzymes from other crustaceans. A novel and unbiased substrate profiling approach was used to uncover the global proteolytic specificity of gastric juice and determine the contribution of cysteine and aspartic acid peptidases. These enzymes were separated by gel electrophoresis and their individual substrate specificities uncovered from the resulting gel bands. This new technique is called zymoMSP. Each cysteine peptidase cleaves a set of unique peptide bonds and the S2 pocket determines their substrate specificity. Finally, affinity chromatography was used to enrich for a digestive cathepsin D1 to compare its substrate specificity and cold-adapted enzymatic properties to mammalian enzymes. We conclude that the H. americanus digestive peptidases may have useful therapeutic applications, due to their cold-adaptation properties and ability to hydrolyze collagen.

The Crystal Structure of GXGD Membrane Protease FlaK

DOE Office of Scientific and Technical Information (OSTI.GOV)

J Hu; Y Xue; S Lee

2011-12-31

The GXGD proteases are polytopic membrane proteins with catalytic activities against membrane-spanning substrates that require a pair of aspartyl residues. Representative members of the family include preflagellin peptidase, type 4 prepilin peptidase, presenilin and signal peptide peptidase. Many GXGD proteases are important in medicine. For example, type 4 prepilin peptidase may contribute to bacterial pathogenesis, and mutations in presenilin are associated with Alzheimer's disease. As yet, there is no atomic-resolution structure in this protease family. Here we report the crystal structure of FlaK, a preflagellin peptidase from Methanococcus maripaludis, solved at 3.6 {angstrom} resolution. The structure contains six transmembrane helices.more » The GXGD motif and a short transmembrane helix, helix 4, are positioned at the centre, surrounded by other transmembrane helices. The crystal structure indicates that the protease must undergo conformational changes to bring the GXGD motif and a second essential aspartyl residue from transmembrane helix 1 into close proximity for catalysis. A comparison of the crystal structure with models of presenilin derived from biochemical analysis reveals three common transmembrane segments that are similarly arranged around the active site. This observation reinforces the idea that the prokaryotic and human proteases are evolutionarily related. The crystal structure presented here provides a framework for understanding the mechanism of the GXGD proteases, and may facilitate the rational design of inhibitors that target specific members of the family.« less

The crystal structure of GXGD membrane protease FlaK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Jian; Xue, Yi; Lee, Sangwon

2011-09-20

The GXGD proteases are polytopic membrane proteins with catalytic activities against membrane-spanning substrates that require a pair of aspartyl residues. Representative members of the family include preflagellin peptidase, type 4 prepilin peptidase, presenilin and signal peptide peptidase. Many GXGD proteases are important in medicine. For example, type 4 prepilin peptidase may contribute to bacterial pathogenesis, and mutations in presenilin are associated with Alzheimer's disease. As yet, there is no atomic-resolution structure in this protease family. Here we report the crystal structure of FlaK, a preflagellin peptidase from Methanococcus maripaludis, solved at 3.6 {angstrom} resolution. The structure contains six transmembrane helices.more » The GXGD motif and a short transmembrane helix, helix 4, are positioned at the centre, surrounded by other transmembrane helices. The crystal structure indicates that the protease must undergo conformational changes to bring the GXGD motif and a second essential aspartyl residue from transmembrane helix 1 into close proximity for catalysis. A comparison of the crystal structure with models of presenilin derived from biochemical analysis reveals three common transmembrane segments that are similarly arranged around the active site. This observation reinforces the idea that the prokaryotic and human proteases are evolutionarily related. The crystal structure presented here provides a framework for understanding the mechanism of the GXGD proteases, and may facilitate the rational design of inhibitors that target specific members of the family.« less

Potential Activities of Freshwater Exo- and Endo-Acting Extracellular Peptidases in East Tennessee and the Pocono Mountains

PubMed Central

Mullen, Lauren; Boerrigter, Kim; Ferriero, Nicholas; Rosalsky, Jeff; Barrett, Abigail van Buren; Murray, Patrick J.; Steen, Andrew D.

2018-01-01

Proteins constitute a particularly bioavailable subset of organic carbon and nitrogen in aquatic environments but must be hydrolyzed by extracellular enzymes prior to being metabolized by microorganisms. Activities of extracellular peptidases (protein-degrading enzymes) have frequently been assayed in freshwater systems, but such studies have been limited to substrates for a single enzyme [leucyl aminopeptidase (Leu-AP)] out of more than 300 biochemically recognized peptidases. Here, we report kinetic measurements of extracellular hydrolysis of five substrates in 28 freshwater bodies in the Delaware Water Gap National Recreation Area in the Pocono Mountains (PA, United States) and near Knoxville (TN, United States), between 2013 and 2016. The assays putatively test for four aminopeptidases (arginyl aminopeptidase, glyclyl aminopeptidase, Leu-AP, and pyroglutamyl aminopeptidase), which cleave N-terminal amino acids from proteins, and trypsin, an endopeptidase, which cleaves proteins mid-chain. Aminopeptidase and the trypsin-like activity were observed in all water bodies, indicating that a diverse set of peptidases is typical in freshwater. However, ratios of peptidase activities were variable among sites: aminopeptidases dominated at some sites and trypsin-like activity at others. At a given site, the ratios remained fairly consistent over time, indicating that they are driven by ecological factors. Studies in which only Leu-AP activity is measured may underestimate the total peptidolytic capacity of an environment, due to the variable contribution of endopeptidases. PMID:29559961

Protective effects of estrogen against vascular calcification via estrogen receptor α-dependent growth arrest-specific gene 6 transactivation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nanao-Hamai, Michiko; Son, Bo-Kyung; Institute of Gerontology, The University of Tokyo, Tokyo

Vascular calcification is one of the major complications of cardiovascular disease and is an independent risk factor for myocardial infarction and cardiac death. Postmenopausal women have a higher prevalence of vascular calcification compared with premenopausal women, suggesting protective effects of estrogen (E2). However, the underlying mechanisms of its beneficial effects remain unclear. In the present study, we examined the inhibitory effects of E2 on vascular smooth muscle cell (VSMC) calcification, and found that growth arrest-specific gene 6 (Gas6), a crucial molecule in vascular calcification, is transactivated by estrogen receptor α (ERα) in response to E2. In human aortic smooth musclemore » cells, physiological levels of E2 inhibited inorganic phosphate (Pi)-induced calcification in a concentration-dependent manner. This inhibitory effect was significantly abolished by MPP, an ERα-selective antagonist, and ERα siRNA, but not by PHTPP, an ERβ-selective antagonist, and ERβ siRNA, implicating an ERα-dependent action. Apoptosis, an essential process for Pi-induced VSMC calcification, was inhibited by E2 in a concentration-dependent manner and further, MPP abolished this inhibition. Mechanistically, E2 restored the inhibited expression of Gas6 and phospho-Akt in Pi-induced apoptosis through ERα. Furthermore, E2 significantly activated Gas6 transcription, and MPP abrogated this E2-dependent Gas6 transactivation. E2-BSA failed to activate Gas6 transcription and to inhibit Ca deposition in VSMC, suggesting beneficial actions of genomic signaling by E2/nuclear ERα. Taken together, these results indicate that E2 exerts inhibitory effects on VSMC apoptosis and calcification through ERα-mediated Gas6 transactivation. These findings indicate a potential therapeutic strategy for the prevention of vascular calcification, especially in postmenopausal women. - Highlights: • E2 inhibits Pi-induced calcification in vascular smooth muscles cells. • E2 inhibits Pi-induced apoptosis by restoration of Gas6-mediated survival pathway. • Gas6 transactivation by E2 is mediated by ERα.« less

Functional analysis of C1 family cysteine peptidases in the larval gut of Tenebrio molitor and Tribolium castaneum

USDA-ARS?s Scientific Manuscript database

We studied protein digestion the tenebrionids Tenebrio molitor and Tribolium castaneum, pests of stored grains and grain products, to identify potential targets for biopesticide development. Tenebrionid larvae have highly compartmentalized guts, with primarily cysteine peptidases in the acidic anter...

Evaluation of Phosphate Fertilizers for the Immobilization of Cd in Contaminated Soils

PubMed Central

Yan, Yin; Zhou, Yi Qun; Liang, Cheng Hua

2015-01-01

A laboratory investigation was conducted to evaluate the efficiency of four phosphate fertilizers, including diammonium phosphate (DAP), potassium phosphate monobasic (MPP), calcium superphosphateon (SSP), and calcium phosphate tribasic (TCP), in terms of the toxicity and bioavailability of Cd in contaminated soils. The efficiency of immobilization was evaluated on the basis of two criteria: (a) the reduction of extractable Cd concentration below the TCLP regulatory level and (b) the Cd changes associated with specific operational soil fractions on the basis of sequential extraction data. Results showed that after 50 d immobilization, the extractable concentrations of Cd in DAP, MPP, SSP, and TCP treated soils decreased from 42.64 mg/kg (in the control) to 23.86, 21.86, 33.89, and 35.59 mg/kg, respectively, with immobilization efficiency in the order of MPP > DAP > SSP > TCP. Results from the assessment of Cd speciation via the sequential extraction procedure revealed that the soluble exchangeable fraction of Cd in soils treated with phosphate fertilizers, especially TCP, was considerably reduced. In addition, the reduction was correspondingly related to the increase in the more stable forms of Cd, that is, the metal bound to manganese oxides and the metal bound to crystalline iron oxides. Treatment efficiency increased as the phosphate dose (according to the molar ratio of PO4/Cd) increased. Immobilization was the most effective under the molar ratio of PO4/Cd at 4:1. PMID:25915051

The neuroprotection of cannabidiol against MPP⁺-induced toxicity in PC12 cells involves trkA receptors, upregulation of axonal and synaptic proteins, neuritogenesis, and might be relevant to Parkinson's disease.

PubMed

Santos, Neife Aparecida Guinaim; Martins, Nádia Maria; Sisti, Flávia Malvestio; Fernandes, Laís Silva; Ferreira, Rafaela Scalco; Queiroz, Regina Helena Costa; Santos, Antônio Cardozo

2015-12-25

Cannabidiol (CBD) is a non-psychoactive constituent of Cannabis sativa with potential to treat neurodegenerative diseases. Its neuroprotection has been mainly associated with anti-inflammatory and antioxidant events; however, other mechanisms might be involved. We investigated the involvement of neuritogenesis, NGF receptors (trkA), NGF, and neuronal proteins in the mechanism of neuroprotection of CBD against MPP(+) toxicity in PC12 cells. CBD increased cell viability, differentiation, and the expression of axonal (GAP-43) and synaptic (synaptophysin and synapsin I) proteins. Its neuritogenic effect was not dependent or additive to NGF, but it was inhibited by K252a (trkA inhibitor). CBD did not increase the expression of NGF, but protected against its decrease induced by MPP(+), probably by an indirect mechanism. We also evaluated the neuritogenesis in SH-SY5Y cells, which do not express trkA receptors. CBD did not induce neuritogenesis in this cellular model, which supports the involvement of trkA receptors. This is the first study to report the involvement of neuronal proteins and trkA in the neuroprotection of CBD. Our findings suggest that CBD has a neurorestorative potential independent of NGF that might contribute to its neuroprotection against MPP(+), a neurotoxin relevant to Parkinson's disease. Copyright © 2015 Elsevier B.V. All rights reserved.

Overexpression of Annexin A1 Suppresses Pro-Inflammatory Factors in PC12 Cells Induced by 1-Methyl-4-Phenylpyridinium

PubMed Central

Kiani-Esfahani, Abbas; Kazemi Sheykhshabani, Sedigheh; Peymani, Maryam; Hashemi, Motahare-Sadat; Ghaedi, Kamran; Nasr-Esfahani, Mohammad Hossein

2016-01-01

Objective Annexin A1 (ANXA1) is suggested to have anti-inflammatory function. However, the precise function of ANXA1 has remained unclear. In this study, we therefore examined the potency of ANXA1 in regulating reactive oxygen species (ROS) production and suppressing pro-inflammatory responses in PC12 cells induced by 1-methyl-4-phenylpyridinium (MPP+). Materials and Methods In this experimental study, cDNA of ANXA1 was cloned and inserted to the PGL268 pEpi-FGM18F vector to produce a recombinant PGL/ANXA1 vector for transfection into the PC12 cells. ANXA1 transfected cells were then treated with MPP+. Apoptosis and the content of pro-inflammatory factors including ROS, Interlukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) were assessed by flow-cytometry, real-time quantitative polymerase chain reaction (RT-qPCR) and western blot in ANXA1-transfected cells and the data were compared with those obtained from mock and control cells. Results Data revealed that overexpression of ANXA1 is associated with decreased levels of ROS and expression level of IL-6 and iNOS transcripts, and NF-κB protein in MPP+ treated PC12 cells. Conclusion ANXA1 may be considered as an agent for prevention of neurodegenerative or inflammatory conditions. PMID:27540524

Overexpression of Annexin A1 Suppresses Pro-Inflammatory Factors in PC12 Cells Induced by 1-Methyl-4-Phenylpyridinium.

PubMed

Kiani-Esfahani, Abbas; Kazemi Sheykhshabani, Sedigheh; Peymani, Maryam; Hashemi, Motahare-Sadat; Ghaedi, Kamran; Nasr-Esfahani, Mohammad Hossein

2016-01-01

Annexin A1 (ANXA1) is suggested to have anti-inflammatory function. However, the precise function of ANXA1 has remained unclear. In this study, we therefore examined the potency of ANXA1 in regulating reactive oxygen species (ROS) production and suppressing pro-inflammatory responses in PC12 cells induced by 1-methyl-4-phenylpyridinium (MPP+). In this experimental study, cDNA of ANXA1 was cloned and inserted to the PGL268 pEpi-FGM18F vector to produce a recombinant PGL/ANXA1 vector for transfection into the PC12 cells. ANXA1 transfected cells were then treated with MPP+. Apoptosis and the content of pro-inflammatory factors including ROS, Interlukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) were assessed by flow-cytometry, real-time quantitative polymerase chain reaction (RT-qPCR) and western blot in ANXA1-transfected cells and the data were compared with those obtained from mock and control cells. Data revealed that overexpression of ANXA1 is associated with decreased levels of ROS and expression level of IL-6 and iNOS transcripts, and NF-κB protein in MPP+ treated PC12 cells. ANXA1 may be considered as an agent for prevention of neurodegenerative or inflammatory conditions.

Effects of a hyperonic many-body force on BΛ values of hypernuclei

NASA Astrophysics Data System (ADS)

Isaka, M.; Yamamoto, Y.; Rijken, Th. A.

2017-04-01

The stiff equation of state (EoS) giving the neutron-star mass of 2 M⊙ suggests the existence of strongly repulsive many-body effects (MBE) not only in nucleon channels but also in hyperonic ones. As a specific model for MBE, the repulsive multi-Pomeron exchange potential (MPP) is added to the two-body interaction together with the phenomenological three-body attraction. For various versions of the Nijmegen interaction models, the MBE parts are determined so as to reproduce the observed data of BΛ. The mass dependence of BΛ values is shown to be reproduced well by adding MBE to the strong MPP repulsion, assuring the stiff EoS of hyperon-mixed neutron-star matter, in which P -state components of the adopted interaction model lead to almost vanishing contributions. The nuclear matter Λ N G -matrix interactions are derived and used in Λ hypernuclei on the basis of the averaged-density approximation (ADA). The BΛ values of hypernuclei with 9 ≤A ≤59 are analyzed in the framework of antisymmetrized molecular dynamics with use of the two types of Λ N G -matrix interactions including strong and weak MPP repulsions. The calculated values of BΛ reproduce the experimental data well within a few hundred keV. The values of BΛ in p states also can be reproduced well, when the ADA is modified to be suitable also for weakly bound Λ states.

Jump-Squat and Half-Squat Exercises: Selective Influences on Speed-Power Performance of Elite Rugby Sevens Players

PubMed Central

Loturco, Irineu; Pereira, Lucas A.; Moraes, José E.; Kitamura, Katia; Cal Abad, César C.; Kobal, Ronaldo; Nakamura, Fábio Y.

2017-01-01

The aim of this study was to evaluate the relation between the maximum mean propulsive power (MPP) obtained in the loaded jump squat (JS) and half squat (HS) exercises and functional performances in vertical jumps, 40 m linear speed (VEL) and change-of-direction (COD) tests, using the median split technique. Twenty-two male rugby sevens players from the Brazilian National Olympic Team (Rio-2016) performed vertical jumping tests (squat and countermovement jumps [SJ and CMJ]), JS and HS exercises, COD speed test and sprinting velocity in 40 m, in this order. Based on the results of the MPP in the JS and HS exercises the participants were divided, using the median split, into four groups as follows: higher JS, lower JS, higher HS, and lower HS. Between-group differences in the functional tasks were detected via magnitude-based inferences. The athletes with higher MPP in the JS were capable of jumping higher and sprinting faster (including the COD speed test) than their weaker counterparts. This pattern was not observed in the HS exercise. To conclude, JS was shown to be more connected to sprinting, COD speed and jumping abilities than HS in elite rugby sevens players and should be preferred for assessing and possibly training elite athletes needing to improve speed-power related abilities. PMID:28114431

Jump-Squat and Half-Squat Exercises: Selective Influences on Speed-Power Performance of Elite Rugby Sevens Players.

PubMed

Loturco, Irineu; Pereira, Lucas A; Moraes, José E; Kitamura, Katia; Cal Abad, César C; Kobal, Ronaldo; Nakamura, Fábio Y

2017-01-01

The aim of this study was to evaluate the relation between the maximum mean propulsive power (MPP) obtained in the loaded jump squat (JS) and half squat (HS) exercises and functional performances in vertical jumps, 40 m linear speed (VEL) and change-of-direction (COD) tests, using the median split technique. Twenty-two male rugby sevens players from the Brazilian National Olympic Team (Rio-2016) performed vertical jumping tests (squat and countermovement jumps [SJ and CMJ]), JS and HS exercises, COD speed test and sprinting velocity in 40 m, in this order. Based on the results of the MPP in the JS and HS exercises the participants were divided, using the median split, into four groups as follows: higher JS, lower JS, higher HS, and lower HS. Between-group differences in the functional tasks were detected via magnitude-based inferences. The athletes with higher MPP in the JS were capable of jumping higher and sprinting faster (including the COD speed test) than their weaker counterparts. This pattern was not observed in the HS exercise. To conclude, JS was shown to be more connected to sprinting, COD speed and jumping abilities than HS in elite rugby sevens players and should be preferred for assessing and possibly training elite athletes needing to improve speed-power related abilities.

GPER: A new tool to protect dopaminergic neurons?

PubMed

Bessa, Agustina; Campos, Filipa Lopes; Videira, Rita Alexandra; Mendes-Oliveira, Julieta; Bessa-Neto, Diogo; Baltazar, Graça

2015-10-01

Parkinson's disease (PD) is characterized by a selective degeneration of nigrostriatal dopaminergic pathway. Epidemiological studies revealed a male predominance of the disease that has been attributed to the female steroid hormones, mainly the estrogen. Estrogen neuroprotective effects have been shown in several studies, however the mechanisms responsible by these effects are still unclear. Previous data from our group revealed that glial cell line-derived neurotrophic factor (GDNF) is crucial to the dopaminergic protection provided by 17β-estradiol, and also suggest that the intracellular estrogen receptors (ERs) are not required for that neuroprotective effects. The present study aimed to investigate the contribution of the G protein-coupled ER (GPER) activation in estrogen-mediated dopaminergic neuroprotection against an insult induced by 1-methyl-4-phenylpyridinium (MPP(+)), and whether GPER neuroprotective effects involve the regulation of GDNF expression. Using primary mesencephalic cultures, we found that GPER activation protects dopaminergic neurons from MPP(+) toxicity in an extent similar to the promoted by a 17β-estradiol. Moreover, GPER activation promotes an increase in GDNF levels. Both, GDNF antibody neutralization or RNA interference-mediated GDNF knockdown prevented the GPER-mediated dopaminergic protection verified in mesencephalic cultures challenged with MPP(+). Overall, these results revealed that G1, a selective agonist of GPER, is able to protect dopaminergic neurons and that GDNF overexpression is a key feature to GPER induced the neuroprotective effects. Copyright © 2015 Elsevier B.V. All rights reserved.

Arsenite in drinking water produces glucose intolerance in pregnant rats and their female offspring.

PubMed

Bonaventura, María Marta; Bourguignon, Nadia Soledad; Bizzozzero, Marianne; Rodriguez, Diego; Ventura, Clara; Cocca, Claudia; Libertun, Carlos; Lux-Lantos, Victoria Adela

2017-02-01

Drinking water is the main source of arsenic exposure. Chronic exposure has been associated with metabolic disorders. Here we studied the effects of arsenic on glucose metabolism, in pregnant and post-partum of dams and their offspring. We administered 5 (A5) or 50 (A50) mg/L of sodium arsenite in drinking water to rats from gestational day 1 (GD1) until two months postpartum (2MPP), and to their offspring from weaning until 8 weeks old. Liver arsenic dose-dependently increased in arsenite-treated rats to levels similar to exposed population. Pregnant A50 rats gained less weight than controls and recovered normal weight at 2MPP. Arsenite-treated pregnant animals showed glucose intolerance on GD16-17, with impaired insulin secretion but normal insulin sensitivity; they showed dose-dependent increased pancreas insulin on GD18. All alterations reverted at 2MPP. Offspring from A50-treated mothers showed lower body weight at birth, 4 and 8 weeks of age, and glucose intolerance in adult females, probably due to insulin secretion and sensitivity alterations. Arsenic alters glucose homeostasis during pregnancy by altering beta-cell function, increasing risk of developing gestational diabetes. In pups, it induces low body weight from birth to 8 weeks of age, and glucose intolerance in females, demonstrating a sex specific response. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structural Basis for Specificity of Propeptide-Enzyme Interaction in Barley C1A Cysteine Peptidases

PubMed Central

Cambra, Inés; Hernández, David; Diaz, Isabel; Martinez, Manuel

2012-01-01

C1A cysteine peptidases are synthesized as inactive proenzymes. Activation takes place by proteolysis cleaving off the inhibitory propeptide. The inhibitory capacity of propeptides from barley cathepsin L and B-like peptidases towards commercial and barley cathepsins has been characterized. Differences in selectivity have been found for propeptides from L-cathepsins against their cognate and non cognate enzymes. Besides, the propeptide from barley cathepsin B was not able to inhibit bovine cathepsin B. Modelling of their three-dimensional structures suggests that most propeptide inhibitory properties can be explained from the interaction between the propeptide and the mature cathepsin structures. Their potential use as biotechnological tools is discussed. PMID:22615948

Cysteine digestive peptidases function as post-glutamine cleaving enzymes in tenebrionid stored product pests

USDA-ARS?s Scientific Manuscript database

Cereals have storage proteins with high amounts of the amino acids glutamine and proline. Therefore, storage pests need to have digestive enzymes that are efficient in hydrolyzing these types of proteins. Post-glutamine cleaving peptidases (PGP) were isolated from the midgut of the stored product pe...

The use of dipeptidyl peptidase-4 inhibitors in patients with type 2 diabetes & chronic kidney disease

PubMed Central

Bittle, Polly A.

2017-01-01

Abstract: There is a need for treatment options in patients with type 2 diabetes mellitus and kidney disease to achieve glucose targets without risk of hypoglycemia. This article describes management options for these patients using glucose-lowering therapies, in particular dipeptidyl peptidase-4 inhibitors. PMID:28225432

Chymotrypsin-like peptidases from Tribolium castaneum: A role in molting revealed by RNA interference

USDA-ARS?s Scientific Manuscript database

Chymotrypsin-like peptidases (CTLPs) of insects are primarily secreted into the gut lumen where they act as digestive enzymes. We studied the gene family encoding CTLPs in the genome of the red flour beetle, Tribolium castaneum. Using an extended search pattern, we identified 14 TcCTLP genes that e...

Effects of Organophosphate Esters on Neuropeptide Systems.

DTIC Science & Technology

1986-03-01

pathways for the synthesis and degradation of neuropeptides involve hydrolytic enzyme reactions which may be mechanistically similar to those catalyzed by...neuropeptide processing and degradation in vitro, and to assess the effect of introducing organophosphates into these systems. The methods used for the...weight precursors by proteolytic cleavage and inactivation, in which the mature neuropeptides are hydrolyzed by peptidases . More importantly

Structural and mutational analyses of dipeptidyl peptidase 11 from Porphyromonas gingivalis reveal the molecular basis for strict substrate specificity

PubMed Central

Sakamoto, Yasumitsu; Suzuki, Yoshiyuki; Iizuka, Ippei; Tateoka, Chika; Roppongi, Saori; Fujimoto, Mayu; Inaka, Koji; Tanaka, Hiroaki; Yamada, Mitsugu; Ohta, Kazunori; Gouda, Hiroaki; Nonaka, Takamasa; Ogasawara, Wataru; Tanaka, Nobutada

2015-01-01

The dipeptidyl peptidase 11 from Porphyromonas gingivalis (PgDPP11) belongs to the S46 family of serine peptidases and preferentially cleaves substrates with Asp/Glu at the P1 position. The molecular mechanism underlying the substrate specificity of PgDPP11, however, is unknown. Here, we report the crystal structure of PgDPP11. The enzyme contains a catalytic domain with a typical double β-barrel fold and a recently identified regulatory α-helical domain. Crystal structure analyses, docking studies, and biochemical studies revealed that the side chain of Arg673 in the S1 subsite is essential for recognition of the Asp/Glu side chain at the P1 position of the bound substrate. Because S46 peptidases are not found in mammals and the Arg673 is conserved among DPP11s, we anticipate that DPP11s could be utilised as targets for antibiotics. In addition, the present structure analyses could be useful templates for the design of specific inhibitors of DPP11s from pathogenic organisms. PMID:26057589

The Enigma of Tripeptidyl-Peptidase II: Dual Roles in Housekeeping and Stress

PubMed Central

Preta, Giulio; de Klark, Rainier; Gavioli, Riccardo; Glas, Rickard

2010-01-01

The tripeptidyl-peptidase II complex consists of repeated 138 kDa subunits, assembled into two twisted strands that form a high molecular weight complex (>5 MDa). TPPII, like many other cytosolic peptidases, plays a role in the ubiquitin-proteasome pathway downstream of the proteasome as well as in the production and destruction of MHC class I antigens and degradation of neuropeptides. Tripeptidyl-peptidase II activity is increased in cells with an increased demand for protein degradation, but whether degradation of cytosolic peptides is the only cell biological role for TPPII has remained unclear. Recent data indicated that TPPII translocates into the nucleus to control DNA damage responses in malignant cells, supporting that cytosolic “housekeeping peptidases” may have additional roles in cell biology, besides their contribution to protein turnover. Overall, TPPII has an emerging importance in several cancer-related fields, such as metabolism, cell death control, and control of genome integrity; roles that are not understood in detail. The present paper reviews the cell biology of TPPII and discusses distinct roles for TPPII in the nucleus and cytosol. PMID:20847939

Characterization of cDNA for human tripeptidyl peptidase II: The N-terminal part of the enzyme is similar to subtilisin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomkinson, B.; Jonsson, A-K

1991-01-01

Tripeptidyl peptidase II is a high molecular weight serine exopeptidase, which has been purified from rat liver and human erythrocytes. Four clones, representing 4453 bp, or 90{percent} of the mRNA of the human enzyme, have been isolated from two different cDNA libraries. One clone, designated A2, was obtained after screening a human B-lymphocyte cDNA library with a degenerated oligonucleotide mixture. The B-lymphocyte cDNA library, obtained from human fibroblasts, were rescreened with a 147 bp fragment from the 5{prime} part of the A2 clone, whereby three different overlapping cDNA clones could be isolated. The deduced amino acid sequence, 1196 amino acidmore » residues, corresponding to the longest open rading frame of the assembled nucleotide sequence, was compared to sequences of current databases. This revealed a 56{percent} similarity between the bacterial enzyme subtilisin and the N-terminal part of tripeptidyl peptidase II. The enzyme was found to be represented by two different mRNAs of 4.2 and 5.0 kilobases, respectively, which probably result from the utilziation of two different polyadenylation sites. Futhermore, cDNA corresponding to both the N-terminal and C-terminal part of tripeptidyl peptidase II hybridized with genomic DNA from mouse, horse, calf, and hen, even under fairly high stringency conditions, indicating that tripeptidyl peptidase II is highly conserved.« less

High-order local maximum principle preserving (MPP) discontinuous Galerkin finite element method for the transport equation

NASA Astrophysics Data System (ADS)

Anderson, R.; Dobrev, V.; Kolev, Tz.; Kuzmin, D.; Quezada de Luna, M.; Rieben, R.; Tomov, V.

2017-04-01

In this work we present a FCT-like Maximum-Principle Preserving (MPP) method to solve the transport equation. We use high-order polynomial spaces; in particular, we consider up to 5th order spaces in two and three dimensions and 23rd order spaces in one dimension. The method combines the concepts of positive basis functions for discontinuous Galerkin finite element spatial discretization, locally defined solution bounds, element-based flux correction, and non-linear local mass redistribution. We consider a simple 1D problem with non-smooth initial data to explain and understand the behavior of different parts of the method. Convergence tests in space indicate that high-order accuracy is achieved. Numerical results from several benchmarks in two and three dimensions are also reported.

Energy harvesting influences electrochemical performance of microbial fuel cells

NASA Astrophysics Data System (ADS)

Lobo, Fernanda Leite; Wang, Xin; Ren, Zhiyong Jason

2017-07-01

Microbial fuel cells (MFCs) can be effective power sources for remote sensing, wastewater treatment and environmental remediation, but their performance needs significant improvement. This study systematically analyzes how active harvesting using electrical circuits increased MFC system outputs as compared to passive resistors not only in the traditional maximal power point (MPP) but also in other desired operating points such as the maximum current point (MCP) and the maximum voltage point (MVP). Results show that active harvesting in MPP increased power output by 81-375% and active harvesting in MCP increased Coulombic efficiency by 207-805% compared with resisters operated at the same points. The cyclic voltammograms revealed redox potential shifts and supported the performance data. The findings demonstrate that active harvesting is a very effective approach to improve MFC performance across different operating points.

The architecture of tomorrow's massively parallel computer

NASA Technical Reports Server (NTRS)

Batcher, Ken

1987-01-01

Goodyear Aerospace delivered the Massively Parallel Processor (MPP) to NASA/Goddard in May 1983, over three years ago. Ever since then, Goodyear has tried to look in a forward direction. There is always some debate as to which way is forward when it comes to supercomputer architecture. Improvements to the MPP's massively parallel architecture are discussed in the areas of data I/O, memory capacity, connectivity, and indirect (or local) addressing. In I/O, transfer rates up to 640 megabytes per second can be achieved. There are devices that can supply the data and accept it at this rate. The memory capacity can be increased up to 128 megabytes in the ARU and over a gigabyte in the staging memory. For connectivity, there are several different kinds of multistage networks that should be considered.

Coherent Electron Transfer at the Ag / Graphite Heterojunction Interface

NASA Astrophysics Data System (ADS)

Tan, Shijing; Dai, Yanan; Zhang, Shengmin; Liu, Liming; Zhao, Jin; Petek, Hrvoje

2018-03-01

Charge transfer in transduction of light to electrical or chemical energy at heterojunctions of metals with semiconductors or semimetals is believed to occur by photogenerated hot electrons in metal undergoing incoherent internal photoemission through the heterojunction interface. Charge transfer, however, can also occur coherently by dipole coupling of electronic bands at the heterojunction interface. Microscopic physical insights into how transfer occurs can be elucidated by following the coherent polarization of the donor and acceptor states on the time scale of electronic dephasing. By time-resolved multiphoton photoemission spectroscopy (MPP), we investigate the coherent electron transfer from an interface state that forms upon chemisorption of Ag nanoclusters onto graphite to a σ symmetry interlayer band of graphite. Multidimensional MPP spectroscopy reveals a resonant two-photon transition, which dephases within 10 fs completing the coherent transfer.

A maximum power point prediction method for group control of photovoltaic water pumping systems based on parameter identification

NASA Astrophysics Data System (ADS)

Chen, B.; Su, J. H.; Guo, L.; Chen, J.

2017-06-01

This paper puts forward a maximum power estimation method based on the photovoltaic array (PVA) model to solve the optimization problems about group control of the PV water pumping systems (PVWPS) at the maximum power point (MPP). This method uses the improved genetic algorithm (GA) for model parameters estimation and identification in view of multi P-V characteristic curves of a PVA model, and then corrects the identification results through least square method. On this basis, the irradiation level and operating temperature under any condition are able to estimate so an accurate PVA model is established and the MPP none-disturbance estimation is achieved. The simulation adopts the proposed GA to determine parameters, and the results verify the accuracy and practicability of the methods.

Multiplexing Short Primers for Viral Family PCR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, S N; Hiddessen, A L; Hara, C A

We describe a Multiplex Primer Prediction (MPP) algorithm to build multiplex compatible primer sets for large, diverse, and unalignable sets of target sequences. The MPP algorithm is scalable to larger target sets than other available software, and it does not require a multiple sequence alignment. We applied it to questions in viral detection, and demonstrated that there are no universally conserved priming sequences among viruses and that it could require an unfeasibly large number of primers ({approx}3700 18-mers or {approx}2000 10-mers) to generate amplicons from all sequenced viruses. We then designed primer sets separately for each viral family, and formore » several diverse species such as foot-and-mouth disease virus, hemagglutinin and neuraminidase segments of influenza A virus, Norwalk virus, and HIV-1.« less

Crystal structure of bacterial cell-surface alginate-binding protein with an M75 peptidase motif

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maruyama, Yukie; Ochiai, Akihito; Mikami, Bunzo

Research highlights: {yields} Bacterial alginate-binding Algp7 is similar to component EfeO of Fe{sup 2+} transporter. {yields} We determined the crystal structure of Algp7 with a metal-binding motif. {yields} Algp7 consists of two helical bundles formed through duplication of a single bundle. {yields} A deep cleft involved in alginate binding locates around the metal-binding site. {yields} Algp7 may function as a Fe{sup 2+}-chelated alginate-binding protein. -- Abstract: A gram-negative Sphingomonas sp. A1 directly incorporates alginate polysaccharide into the cytoplasm via the cell-surface pit and ABC transporter. A cell-surface alginate-binding protein, Algp7, functions as a concentrator of the polysaccharide in the pit.more » Based on the primary structure and genetic organization in the bacterial genome, Algp7 was found to be homologous to an M75 peptidase motif-containing EfeO, a component of a ferrous ion transporter. Despite the presence of an M75 peptidase motif with high similarity, the Algp7 protein purified from recombinant Escherichia coli cells was inert on insulin B chain and N-benzoyl-Phe-Val-Arg-p-nitroanilide, both of which are substrates for a typical M75 peptidase, imelysin, from Pseudomonas aeruginosa. The X-ray crystallographic structure of Algp7 was determined at 2.10 A resolution by single-wavelength anomalous diffraction. Although a metal-binding motif, HxxE, conserved in zinc ion-dependent M75 peptidases is also found in Algp7, the crystal structure of Algp7 contains no metal even at the motif. The protein consists of two structurally similar up-and-down helical bundles as the basic scaffold. A deep cleft between the bundles is sufficiently large to accommodate macromolecules such as alginate polysaccharide. This is the first structural report on a bacterial cell-surface alginate-binding protein with an M75 peptidase motif.« less

Characterization of papain-like isoenzymes from latex of Asclepias curassavica by molecular biology validated by proteomic approach.

PubMed

Obregón, Walter D; Liggieri, Constanza S; Trejo, Sebastian A; Avilés, Francesc X; Vairo-Cavalli, Sandra E; Priolo, Nora S

2009-01-01

Latices from Asclepias spp are used in wound healing and the treatment of some digestive disorders. These pharmacological actions have been attributed to the presence of cysteine proteases in these milky latices. Asclepias curassavica (Asclepiadaceae), "scarlet milkweed" is a perennial subshrub native to South America. In the current paper we report a new approach directed at the selective biochemical and molecular characterization of asclepain cI (acI) and asclepain cII (acII), the enzymes responsible for the proteolytic activity of the scarlet milkweed latex. SDS-PAGE spots of both purified peptidases were digested with trypsin and Peptide Mass Fingerprints (PMFs) obtained showed no equivalent peptides. No identification was possible by MASCOT search due to the paucity of information concerning Asclepiadaceae latex cysteine proteinases available in databases. From total RNA extracted from latex samples, cDNA of both peptidases was obtained by RT-PCR using degenerate primers encoding Asclepiadaceae cysteine peptidase conserved domains. Theoretical PMFs of partial polypeptide sequences obtained by cloning (186 and 185 amino acids) were compared with empirical PMFs, confirming that the sequences of 186 and 185 amino acids correspond to acI and acII, respectively. N-terminal sequences of acI and acII, characterized by Edman sequencing, were overlapped with those coming from the cDNA to obtain the full-length sequence of both mature peptidases (212 and 211 residues respectively). Alignment and phylogenetic analysis confirmed that acI and acII belong to the subfamily C1A forming a new group of papain-like cysteine peptidases together with asclepain f from Asclepias fruticosa. We conclude that PMF could be adopted as an excellent tool to differentiate, in a fast and unequivocal way, peptidases with very similar physicochemical and functional properties, with advantages over other conventional methods (for instance enzyme kinetics) that are time consuming and afford less reliable results.

Role of inhibitors of serine peptidases in protecting Leishmania donovani against the hydrolytic peptidases of sand fly midgut.

PubMed

Verma, Sudha; Das, Sushmita; Mandal, Abhishek; Ansari, Md Yousuf; Kumari, Sujata; Mansuri, Rani; Kumar, Ajay; Singh, Ruby; Saini, Savita; Abhishek, Kumar; Kumar, Vijay; Sahoo, Ganesh Chandra; Das, Pradeep

2017-06-23

In vector-borne diseases such as leishmaniasis, the sand fly midgut is considered to be an important site for vector-parasite interaction. Digestive enzymes including serine peptidases such as trypsin and chymotrypsin, which are secreted in the midgut are one of the obstacles for Leishmania in establishing a successful infection. The presence of some natural inhibitors of serine peptidases (ISPs) has recently been reported in Leishmania. In the present study, we deciphered the role of these ISPs in the survival of Leishmania donovani in the hostile sand fly midgut environment. In silico and co-immunoprecipitation studies were performed to observe the interaction of L. donovani ISPs with trypsin and chymotrypsin. Zymography and in vitro enzyme assays were carried out to observe the inhibitory effect of purified recombinant ISPs of L. donovani (rLdISPs) on trypsin, chymotrypsin and the sand fly midgut peptidases. The expression of ISPs in the amastigote to promastigote transition stages were studied by semi-quantitative RT-PCR and Western blot. The role of LdISP on the survival of ISP overexpressed (OE) and ISP knocked down (KD) Leishmania parasites inside the sand fly gut was investigated by in vitro and in vivo cell viability assays. We identified two ecotin-like genes in L. donovani, LdISP1 and LdISP2. In silico and co-immunoprecipitation results clearly suggest a strong interaction of LdISP molecules with trypsin and chymotrypsin. Zymography and in vitro enzyme assay confirmed the inhibitory effect of rLdISP on trypsin, chymotrypsin and the sand fly midgut peptidases. The expression of LdISP2 was found to be strongly associated with the amastigote to promastigote phase transition. The activities of the digestive enzymes were found to be significantly reduced in the infected sand flies when compared to uninfected. To our knowledge, our study is the first report showing the possible reduction of chymotrypsin activity in L. donovani infected sand flies compared to uninfected. Interestingly, during the early transition stage, substantial killing was observed in ISP2 knocked down (ISP2KD) parasites compared to wild type (WT), whereas ISP1 knocked down (ISP1KD) parasites remained viable. Therefore, our study clearly indicates that LdISP2 is a more effective inhibitor of serine peptidases than LdISP1. Our results suggest that the lack of ISP2 is detrimental to the parasites during the early transition from amastigotes to promastigotes. Moreover, the results of the present study demonstrated for the first time that LdISP2 has an important role in the inhibition of peptidases and promoting L. donovani survival inside the Phlebotomus argentipes midgut.

Biotechnica 󈨙 International Congress for Biotechnology Held in Hannover, Germany, D.R. on 8-10 October 1985,

DTIC Science & Technology

1986-02-27

Cross flow Filtration gelfiltratoi- Sjir.N dvng flttration filtration - Partition ad rlipon - - P trec pilaton Figure I. Downstream processing of...transformation the Nuclear Research Center, Jilich, into the L-amino acid is achieved in an West Germany. Until now the degrading enzyme reactor. This time...Some enzymatic processes can be car- of a hydrolase is the use of a peptidase tied out on a practical scale only in to produce peptides. One route to

Comparative Analysis of Binding Kinetics and Thermodynamics of Dipeptidyl Peptidase-4 Inhibitors and Their Relationship to Structure.

PubMed

Schnapp, Gisela; Klein, Thomas; Hoevels, Yvette; Bakker, Remko A; Nar, Herbert

2016-08-25

The binding kinetics and thermodynamics of dipeptidyl peptidase (DPP)-4 inhibitors (gliptins) were investigated using surface plasmon resonance and isothermal titration calorimetry. Binding of gliptins to DPP-4 is a rapid electrostatically driven process. Off-rates were generally slow partly because of reversible covalent bond formation by some gliptins, and partly because of strong and extensive interactions. Binding of all gliptins is enthalpy-dominated due to strong ionic interactions and strong solvent-shielded hydrogen bonds. Using a congeneric series of molecules which represented the intermediates in the lead optimization program of linagliptin, the onset of slow binding kinetics and development of the thermodynamic repertoire were analyzed in the context of incremental changes of the chemical structures. All compounds rapidly associated, and therefore the optimization of affinity and residence time is highly correlated. The major contributor to the increasing free energy of binding was a strong increase of binding enthalpy, whereas entropic contributions remained low and constant despite significant addition of lipophilicity.

Tripeptidyl Peptidase II Is Required for c-MYC-Induced Centriole Overduplication and a Novel Therapeutic Target in c-MYC-Associated Neoplasms.

PubMed

Duensing, Stefan; Darr, Sebastian; Cuevas, Rolando; Melquiot, Nadja; Brickner, Anthony G; Duensing, Anette; Münger, Karl

2010-09-01

Centrosome aberrations are frequently detected in c-MYC-associated human malignancies. Here, we show that c-MYC-induced centrosome and centriole overduplication critically depend on the protease tripeptidyl peptidase II (TPPII). We found that TPPII localizes to centrosomes and that overexpression of TPPII, similar to c-MYC, can disrupt centriole duplication control and cause centriole multiplication, a process during which maternal centrioles nucleate the formation of more than a single daughter centriole. We report that inactivation of TPPII using chemical inhibitors or siRNA-mediated protein knockdown effectively reduced c-MYC-induced centriole overduplication. Remarkably, the potent and selective TPPII inhibitor butabindide not only potently suppressed centriole aberrations but also caused significant cell death and growth suppression in aggressive human Burkitt lymphoma cells with c-MYC overexpression. Taken together, these results highlight the role of TPPII in c-MYC-induced centriole overduplication and encourage further studies to explore TPPII as a novel antineoplastic drug target.

Tripeptidyl Peptidase II Is Required for c-MYC–Induced Centriole Overduplication and a Novel Therapeutic Target in c-MYC–Associated Neoplasms

PubMed Central

Duensing, Stefan; Darr, Sebastian; Cuevas, Rolando; Melquiot, Nadja; Brickner, Anthony G.; Duensing, Anette; Münger, Karl

2010-01-01

Centrosome aberrations are frequently detected in c-MYC–associated human malignancies. Here, we show that c-MYC–induced centrosome and centriole overduplication critically depend on the protease tripeptidyl peptidase II (TPPII). We found that TPPII localizes to centrosomes and that overexpression of TPPII, similar to c-MYC, can disrupt centriole duplication control and cause centriole multiplication, a process during which maternal centrioles nucleate the formation of more than a single daughter centriole. We report that inactivation of TPPII using chemical inhibitors or siRNA-mediated protein knockdown effectively reduced c-MYC–induced centriole overduplication. Remarkably, the potent and selective TPPII inhibitor butabindide not only potently suppressed centriole aberrations but also caused significant cell death and growth suppression in aggressive human Burkitt lymphoma cells with c-MYC overexpression. Taken together, these results highlight the role of TPPII in c-MYC–induced centriole overduplication and encourage further studies to explore TPPII as a novel antineoplastic drug target. PMID:21647238

Anti-Angiogenic Action of Neutral Endopeptidase

DTIC Science & Technology

2006-11-01

natriuretic factor, substance P , bradykinin, oxytocin, Leu- and Met-enkephalins, neurotensin, bombesin, endothelin-1 (ET-1), and beta amyloid. Loss...NOTES 14. ABSTRACT: Please see attached. 15. SUBJECT TERMS Angiogenesis, Cell surface peptidase , Neutral endopeptidase, Basic fibroblast growth...effective therapies for patients with prostate cancer. Cell-surface peptidases are the guardians of the cell against small stimulatory peptides

Anti-Angiogenic Action of Neutral Endopeptidase

DTIC Science & Technology

2005-11-30

side of hydrophobic amino acids and inactivates a variety of physiologically active peptides, including atrial natriuretic factor, substance P ...follows. 15. SUBJECT TERMS Angiogenesis, Cell surface peptidase , Neutral endopeptidase, Basic fibroblast growth factor, Prostate cancer Proteolysis 16...patients with prostate cancer. Cell-surface peptidases are the guardians of the cell against small stimulatory peptides, functioning to control growth

Human dipeptidyl peptidase III acts as a post-proline-cleaving enzyme on endomorphins.

PubMed

Barsun, Marina; Jajcanin, Nina; Vukelić, Bojana; Spoljarić, Jasminka; Abramić, Marija

2007-03-01

Dipeptidyl peptidase III (DPP III) is a zinc exopeptidase with an implied role in the mammalian pain-modulatory system owing to its high affinity for enkephalins and localisation in the superficial laminae of the spinal cord dorsal horn. Our study revealed that this human enzyme hydrolyses opioid peptides belonging to three new groups, endomorphins, hemorphins and exorphins. The enzymatic hydrolysis products of endomorphin-1 were separated and quantified by capillary electrophoresis and the kinetic parameters were determined for human DPP III and rat DPP IV. Both peptidases cleave endomorphin-1 at comparable rates, with liberation of the N-terminal Tyr-Pro. This is the first evidence of DPP III acting as an endomorphin-cleaving enzyme.

Exploration of the binding modes of buffalo PGRP1 receptor complexed with meso-diaminopimelic acid and lysine-type peptidoglycans by molecular dynamics simulation and free energy calculation.

PubMed

Sahoo, Bikash Ranjan; Dubey, Praveen Kumar; Goyal, Shubham; Bhoi, Gopal Krushna; Lenka, Santosh Kumar; Maharana, Jitendra; Pradhan, Sukanta Kumar; Kataria, Ranjit Singh

2014-09-05

The peptidoglycan recognition proteins (PGRPs) are the key components of innate-immunity, and are highly specific for the recognition of bacterial peptidoglycans (PGN). Among different mammalian PGRPs, the PGRP1 binds to murein PGN of Gram-positive bacteria (lysine-type) and also have bactericidal activity towards Gram-negative bacteria (diaminopimelic acid or Dap-type). Buffaloes are the major sources of milk and meat in Asian sub-continents and are highly exposed to bacterial infections. The PGRP activates the innate-immune signaling, but their studies has been confined to limited species due to lack of structural and functional information. So, to understand the structural constituents, 3D model of buffalo PGRP1 (bfPGRP1) was constructed and conformational and dynamics properties of bfPGRP1 was studied. The bfPGRP1 model highly resembled human and camel PGRP structure, and shared a highly flexible N-terminus and centrally placed L-shaped cleft. Docking simulation of muramyl-tripeptide, tetrapeptide, pentapeptide-Dap-(MTP-Dap, MTrP-Dap and MPP-Dap) and lysine-type (MTP-Lys, MTrP-Lys and MPP-Lys) in AutoDock 4.2 and ArgusLab 4.0.1 anticipated β1, α2, α4, β4, and loops connecting β1-α2, α2-β2, β3-β4 and α4-α5 as the key interacting domains. The bfPGRP1-ligand complex molecular dynamics simulation followed by free binding energy (BE) computation conceded BE values of -18.30, -35.53, -41.80, -25.03, -24.62 and -22.30 kJ mol(-1) for MTP-Dap, MTrP-Dap, MPP-Dap, MTP-Lys, MTrP-Lys and MPP-Lys, respectively. The groove-surface and key binding residues involved in PGN-Dap and Lys-type interaction intended by the molecular docking, and were also accompanied by significant BE values directed their importance in pharmacogenomics, and warrants further in vivo studies for drug targeting and immune signaling pathways exploration. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Sources of sedimentary PAHs in tropical Asian waters: differentiation between pyrogenic and petrogenic sources by alkyl homolog abundance.

PubMed

Saha, Mahua; Togo, Ayako; Mizukawa, Kaoruko; Murakami, Michio; Takada, Hideshige; Zakaria, Mohamad P; Chiem, Nguyen H; Tuyen, Bui Cach; Prudente, Maricar; Boonyatumanond, Ruchaya; Sarkar, Santosh Kumar; Bhattacharya, Badal; Mishra, Pravakar; Tana, Touch Seang

2009-02-01

We collected surface sediment samples from 174 locations in India, Indonesia, Malaysia, Thailand, Vietnam, Cambodia, Laos, and the Philippines and analyzed them for polycyclic aromatic hydrocarbons (PAHs) and hopanes. PAHs were widely distributed in the sediments, with comparatively higher concentrations in urban areas (Sigma PAHs: approximately 1000 to approximately 100,000 ng/g-dry) than in rural areas ( approximately 10 to approximately 100g-dry), indicating large sources of PAHs in urban areas. To distinguish petrogenic and pyrogenic sources of PAHs, we calculated the ratios of alkyl PAHs to parent PAHs: methylphenanthrenes to phenanthrene (MP/P), methylpyrenes+methylfluoranthenes to pyrene+fluoranthene (MPy/Py), and methylchrysenes+methylbenz[a]anthracenes to chrysene+benz[a]anthracene (MC/C). Analysis of source materials (crude oil, automobile exhaust, and coal and wood combustion products) gave thresholds of MP/P=0.4, MPy/Py=0.5, and MC/C=1.0 for exclusive combustion origin. All the combustion product samples had the ratios of alkyl PAHs to parent PAHs below these threshold values. Contributions of petrogenic and pyrogenic sources to the sedimentary PAHs were uneven among the homologs: the phenanthrene series had a greater petrogenic contribution, whereas the chrysene series had a greater pyrogenic contribution. All the Indian sediments showed a strong pyrogenic signature with MP/P approximately 0.5, MPy/Py approximately 0.1, and MC/C approximately 0.2, together with depletion of hopanes indicating intensive inputs of combustion products of coal and/or wood, probably due to the heavy dependence on these fuels as sources of energy. In contrast, sedimentary PAHs from all other tropical Asian cities were abundant in alkylated PAHs with MP/P approximately 1-4, MPy/Py approximately 0.3-1, and MC/C approximately 0.2-1.0, suggesting a ubiquitous input of petrogenic PAHs. Petrogenic contributions to PAH homologs varied among the countries: largest in Malaysia whereas inferior in Laos. The higher abundance of alkylated PAHs together with constant hopane profiles suggests widespread inputs of automobile-derived petrogenic PAHs to Asian waters.

Three extracellular dipeptidyl peptidases found in Aspergillus oryzae show varying substrate specificities.

PubMed

Maeda, Hiroshi; Sakai, Daisuke; Kobayashi, Takuji; Morita, Hiroto; Okamoto, Ayako; Takeuchi, Michio; Kusumoto, Ken-Ichi; Amano, Hitoshi; Ishida, Hiroki; Yamagata, Youhei

2016-06-01

Three extracellular dipeptidyl peptidase genes, dppB, dppE, and dppF, were unveiled by sequence analysis of the Aspergillus oryzae genome. We investigated their differential enzymatic profiles, in order to gain an understanding of the diversity of these genes. The three dipeptidyl peptidases were expressed using Aspergillus nidulans as the host. Each recombinant enzyme was purified and subsequently characterized. The enzymes displayed similar optimum pH values, but optimum temperatures, pH stabilities, and substrate specificities varied. DppB was identified as a Xaa-Prolyl dipeptidyl peptidase, while DppE scissile substrates were similar to the substrates for Aspergillus fumigatus DPPV (AfDPPV). DppF was found to be a novel enzyme that could digest both substrates for A. fumigatus DPPIV and AfDPPV. Semi-quantitative PCR revealed that the transcription of dppB in A. oryzae was induced by protein substrates and repressed by the addition of an inorganic nitrogen source, despite the presence of protein substrates. The transcription of dppE depended on its growth time, while the transcription of dppF was not affected by the type of the nitrogen source in the medium, and it started during the early stage of the fungal growth. Based on these results, we conclude that these enzymes may represent the nutrition acquisition enzymes. Additionally, DppF may be one of the sensor peptidases responsible for the detection of the protein substrates in A. oryzae environment. DppB may be involved in nitrogen assimilation control, since the transcription of dppB was repressed by NaNO3, despite the presence of protein substrates.

α2-Macroglobulin Capture Allows Detection of Mast Cell Chymase in Serum and Creates a Circulating Reservoir of Angiotensin II-generating Activity1

PubMed Central

Raymond, Wilfred W.; Su, Sharon; Makarova, Anastasia; Wilson, Todd M.; Carter, Melody C.; Metcalfe, Dean D.; Caughey, George H.

2009-01-01

Human chymase is a highly efficient angiotensin II-generating serine peptidase expressed by the MCTC subset of mast cells. When secreted from degranulating cells, it can interact with a variety of circulating anti-peptidases, but is mostly captured by α2-macroglobulin, which sequesters peptidases in a cage-like structure that precludes interactions with large protein substrates and inhibitors, like serpins. The present work shows that α2-macroglobulin-bound chymase remains accessible to small substrates, including angiotensin I, with activity in serum that is stable with prolonged incubation. We used α2-macroglobulin capture to develop a sensitive, microtiter plate-based assay for serum chymase, assisted by a novel substrate synthesized based on results of combinatorial screening of peptide substrates. The substrate has low background hydrolysis in serum and is chymase-selective, with minimal cleavage by the chymotryptic peptidases cathepsin G and chymotrypsin. The assay detects activity in chymase-spiked serum with a threshold of ~1 pM (30 pg/ml), and reveals native chymase activity in serum of most subjects with systemic mastocytosis. α2-Macroglobulin-bound chymase generates angiotensin II in chymase-spiked serum, and appears in native serum as chymostatin-inhibited activity, which can exceed activity of captopril-sensitive angiotensin converting enzyme. These findings suggest that chymase bound to α2-macroglobulin is active, that the circulating complex is an angiotensin-converting enzyme inhibitor-resistant reservoir of angiotensin II-generating activity, and that α2-macroglobulin capture may be exploited in assessing systemic release of secreted peptidases. PMID:19380825

Peptidomics approach to elucidate the proteolytic regulation of bioactive peptides

PubMed Central

Kim, Yun-Gon; Lone, Anna Mari; Nolte, Whitney M.; Saghatelian, Alan

2012-01-01

Peptide hormones and neuropeptides have important roles in physiology and therefore the regulation of these bioactive peptides is of great interest. In some cases proteolysis controls the concentrations and signaling of bioactive peptides, and the peptidases that mediate this biochemistry have proven to be extremely successful drug targets. Due to the lack of any general method to identify these peptidases, however, the role of proteolysis in the regulation of most neuropeptides and peptide hormones is unknown. This limitation prompted us to develop an advanced peptidomics-based strategy to identify the peptidases responsible for the proteolysis of significant bioactive peptides. The application of this approach to calcitonin gene-related peptide (CGRP), a neuropeptide associated with blood pressure and migraine, revealed the endogenous CGRP cleavage sites. This information was then used to biochemically purify the peptidase capable of proteolysis of CGRP at those cleavage sites, which led to the identification of insulin-degrading enzyme (IDE) as a candidate CGRP-degrading enzyme. CGRP had not been identified as an IDE substrate before and we tested the physiological relevance of this interaction by quantitative measurements of CGRP using IDE null (IDE−/−) mice. In the absence of IDE, full-length CGRP levels are elevated in vivo, confirming IDE as an endogenous CGRP-degrading enzyme. By linking CGRP and IDE, this strategy uncovers a previously unknown pathway for CGRP regulation and characterizes an additional role for IDE. More generally, this work suggests that this may be an effective general strategy for characterizing these pathways and peptidases moving forward. PMID:22586115

Susceptibility of Phytomonas serpens to calpain inhibitors in vitro: interference on the proliferation, ultrastructure, cysteine peptidase expression and interaction with the invertebrate host.

PubMed

Oliveira, Simone Santiago Carvalho de; Gonçalves, Diego de Souza; Garcia-Gomes, Aline Dos Santos; Gonçalves, Inês Correa; Seabra, Sergio Henrique; Menna-Barreto, Rubem Figueiredo; Lopes, Angela Hampshire de Carvalho Santos; D'Avila-Levy, Claudia Masini; Santos, André Luis Souza Dos; Branquinha, Marta Helena

2017-01-01

A pleiotropic response to the calpain inhibitor MDL28170 was detected in the tomato parasite Phytomonas serpens. Ultrastructural studies revealed that MDL28170 caused mitochondrial swelling, shortening of flagellum and disruption of trans Golgi network. This effect was correlated to the inhibition in processing of cruzipain-like molecules, which presented an increase in expression paralleled by decreased proteolytic activity. Concomitantly, a calcium-dependent cysteine peptidase was detected in the parasite extract, the activity of which was repressed by pre-incubation of parasites with MDL28170. Flow cytometry and Western blotting analyses revealed the differential expression of calpain-like proteins (CALPs) in response to the pre-incubation of parasites with the MDL28170, and confocal fluorescence microscopy confirmed their surface location. The interaction of promastigotes with explanted salivary glands of the insect Oncopeltus fasciatus was reduced when parasites were pre-treated with MDL28170, which was correlated to reduced levels of surface cruzipain-like and gp63-like molecules. Treatment of parasites with anti-Drosophila melanogaster (Dm) calpain antibody also decreased the adhesion process. Additionally, parasites recovered from the interaction process presented higher levels of surface cruzipain-like and gp63-like molecules, with similar levels of CALPs cross-reactive to anti-Dm-calpain antibody. The results confirm the importance of exploring the use of calpain inhibitors in studying parasites' physiology.

Susceptibility of Phytomonas serpens to calpain inhibitors in vitro: interference on the proliferation, ultrastructure, cysteine peptidase expression and interaction with the invertebrate host

PubMed Central

de Oliveira, Simone Santiago Carvalho; Gonçalves, Diego de Souza; Garcia-Gomes, Aline dos Santos; Gonçalves, Inês Correa; Seabra, Sergio Henrique; Menna-Barreto, Rubem Figueiredo; Lopes, Angela Hampshire de Carvalho Santos; D’Avila-Levy, Claudia Masini; dos Santos, André Luis Souza; Branquinha, Marta Helena

2016-01-01

A pleiotropic response to the calpain inhibitor MDL28170 was detected in the tomato parasite Phytomonas serpens. Ultrastructural studies revealed that MDL28170 caused mitochondrial swelling, shortening of flagellum and disruption of trans Golgi network. This effect was correlated to the inhibition in processing of cruzipain-like molecules, which presented an increase in expression paralleled by decreased proteolytic activity. Concomitantly, a calcium-dependent cysteine peptidase was detected in the parasite extract, the activity of which was repressed by pre-incubation of parasites with MDL28170. Flow cytometry and Western blotting analyses revealed the differential expression of calpain-like proteins (CALPs) in response to the pre-incubation of parasites with the MDL28170, and confocal fluorescence microscopy confirmed their surface location. The interaction of promastigotes with explanted salivary glands of the insect Oncopeltus fasciatus was reduced when parasites were pre-treated with MDL28170, which was correlated to reduced levels of surface cruzipain-like and gp63-like molecules. Treatment of parasites with anti-Drosophila melanogaster (Dm) calpain antibody also decreased the adhesion process. Additionally, parasites recovered from the interaction process presented higher levels of surface cruzipain-like and gp63-like molecules, with similar levels of CALPs cross-reactive to anti-Dm-calpain antibody. The results confirm the importance of exploring the use of calpain inhibitors in studying parasites’ physiology. PMID:27925020

Latex peptidases of Calotropis procera for dehairing of leather as an alternative to environmentally toxic sodium sulfide treatment.

PubMed

Lopéz, Laura M I; Viana, Carolina A; Errasti, María E; Garro, María L; Martegani, José E; Mazzilli, Germán A; Freitas, Cléverson D T; Araújo, Ídila M S; da Silva, Rafaela O; Ramos, Márcio V

2017-09-01

Dehairing of crude leather is a critical stage performed at the beginning of its processing to obtain industrially useful pieces. Tanneries traditionally apply a chemical process based on sodium sulfide. Since this chemical reactive is environmentally toxic and inefficiently recycled, innovative protocols for reducing or eliminating its use in leather depilation are welcomed. Therefore, latex peptidases from Calotropis procera (CpLP) and Cryptostegia grandiflora (CgLP) were assayed for this purpose. Enzyme activity on substrates representative of skin such as hide powder azure (U HPA ), elastin (U E ), azocollagen (U AZOCOL ), keratin (U K ), and epidermis (U EP ) was determined, while depilation activity was assayed on cow hide. Only CpLP was active against keratin (13.4 U K ) and only CgLP was active against elastin (0.12 U E ). CpLP (93.0 U HPA , 403.6 U AZOCOL , 36.3 U EP ) showed higher activity against the other substrates than CgLP (47.6 U HPA , 261.5 U AZOCOL , 8.5 U EP ). In pilot assays, CpLP (0.05% w/v with sodium sulfite 0.6% w/v as activator) released hairs from cow hide pieces. Macroscopic and microscopic analyses of the hide revealed that the dehairing process was complete and the leather structure was preserved. The proteolytic system of C. procera is a suitable bioresources to be exploited by tanneries.

Visualization of unsteady computational fluid dynamics

NASA Astrophysics Data System (ADS)

Haimes, Robert

1994-11-01

A brief summary of the computer environment used for calculating three dimensional unsteady Computational Fluid Dynamic (CFD) results is presented. This environment requires a super computer as well as massively parallel processors (MPP's) and clusters of workstations acting as a single MPP (by concurrently working on the same task) provide the required computational bandwidth for CFD calculations of transient problems. The cluster of reduced instruction set computers (RISC) is a recent advent based on the low cost and high performance that workstation vendors provide. The cluster, with the proper software can act as a multiple instruction/multiple data (MIMD) machine. A new set of software tools is being designed specifically to address visualizing 3D unsteady CFD results in these environments. Three user's manuals for the parallel version of Visual3, pV3, revision 1.00 make up the bulk of this report.

Visualization of unsteady computational fluid dynamics

NASA Technical Reports Server (NTRS)

Haimes, Robert

1994-01-01

A brief summary of the computer environment used for calculating three dimensional unsteady Computational Fluid Dynamic (CFD) results is presented. This environment requires a super computer as well as massively parallel processors (MPP's) and clusters of workstations acting as a single MPP (by concurrently working on the same task) provide the required computational bandwidth for CFD calculations of transient problems. The cluster of reduced instruction set computers (RISC) is a recent advent based on the low cost and high performance that workstation vendors provide. The cluster, with the proper software can act as a multiple instruction/multiple data (MIMD) machine. A new set of software tools is being designed specifically to address visualizing 3D unsteady CFD results in these environments. Three user's manuals for the parallel version of Visual3, pV3, revision 1.00 make up the bulk of this report.

How the Second Law of Thermodynamics Has Informed Ecosystem Ecology through Its History

NASA Astrophysics Data System (ADS)

Chapman, E. J.; Childers, D. L.; Vallino, J. J.

2014-12-01

Throughout the history of ecosystem ecology many attempts have been made to develop a general principle governing how systems develop and organize. We reviewed the historical developments that led to conceptualization of several goal-oriented principles in ecosystem ecology and the relationships among them. We focused our review on two prominent principles—the Maximum Power Principle and the Maximum Entropy Production Principle—and the literature that applies to both. While these principles have considerable conceptual overlap and both use concepts in physics (power and entropy), we found considerable differences in their historical development, the disciplines that apply these principles, and their adoption in the literature. We reviewed the literature using Web of Science keyword searches for the MPP, the MEPP, as well as for papers that cited pioneers in the MPP and the MEPP development. From the 6000 papers that our keyword searches returned, we limited our further meta-analysis to 32 papers by focusing on studies with a foundation in ecosystems research. Despite these seemingly disparate pasts, we concluded that the conceptual approaches of these two principles were more similar than dissimilar and that maximization of power in ecosystems occurs with maximum entropy production. We also found that these two principles have great potential to explain how systems develop, organize, and function, but there are no widely agreed upon theoretical derivations for the MEPP or the MPP, possibly hindering their broader use in ecological research. We end with recommendations for how ecosystems-level studies may better use these principles.

Municipal solid waste management in Phnom Penh, capital city of Cambodia.

PubMed

Seng, Bunrith; Kaneko, Hidehiro; Hirayama, Kimiaki; Katayama-Hirayama, Keiko

2011-05-01

This paper presents an overview of municipal solid waste management (MSWM) for both technical and regulatory arrangements in the municipality of Phnom Penh (MPP), Cambodia. Problems with the current MSWM are identified, and challenges and recommendations for future improvement are also given in this paper. MPP is a small city with a total area of approximately 374 km(2) and an urban population of about 1.3 million in 2008. For the last 14 years, average annual municipal solid waste (MSW) generated in MPP has increased rapidly from 0.136 million tons in 1995 to 0.361 million tons in 2008. The gross generation rate of MSW per capita was 0.74 kg day(-1). However, the per capita household waste generation was 0.487 kg day(- 1). At 63.3%, food waste is the predominant portion of generated waste, followed by plastics (15.5%), grass and wood (6.8%), and paper and cardboard (6.4%). The remaining waste, including metals, glass, rubber/leather, textiles, and ceramic/ stone, accounted for less than 3%. Waste recycling through informal sectors is very active; recycled waste accounted for about 9.3% of all waste generated in 2003. Currently, the overall technical arrangement, including storage and discharge, collection and transport, and disposal, is still in poor condition, which leads to environmental and health risks. These problems should be solved by improving legislation, environmental education, solid waste management facilities, and management of the waste scavengers.

Expression, purification and characterisation of two variant cysteine peptidases from Trypanosoma congolense with active site substitutions.

PubMed

Pillay, Davita; Boulangé, Alain F; Coetzer, Theresa H T

2010-12-01

Congopain, the major cysteine peptidase of Trypanosoma congolense is an attractive candidate for an anti-disease vaccine and target for the design of specific inhibitors. A complicating factor for the inclusion of congopain in a vaccine is that multiple variants of congopain are present in the genome of the parasite. In order to determine whether the variant congopain-like genes code for peptidases with enzymatic activities different to those of congopain, two variants were cloned and expressed. Two truncated catalytic domain variants were recombinantly expressed in Pichia pastoris. The two expressed catalytic domain variants differed slightly from one another in substrate preferences and also from that of C2 (the recombinant truncated form of congopain). Surprisingly, a variant with the catalytic triad Ser(25), His(159) and Asn(175) was shown to be active against classical cysteine peptidase substrates and inhibited by E-64, a class-specific cysteine protease inhibitor. Both catalytic domain clones and C2 had pH optima of either 6.0 or 6.5 implying that these congopain-like proteases are likely to be expressed and active in the bloodstream of the host animal. Copyright © 2010 Elsevier Inc. All rights reserved.

Functional roles of cell surface peptidases in reproductive organs

PubMed Central

2004-01-01

A number of biologically active peptides have been proposed to regulate function and differentiation of reproductive organs in an autocrine and/or paracrine fashion. Regulation of the local concentrations of these peptides is one of the important factors influencing their physiological effects on target cells. Membrane‐bound cell surface peptidases can activate or inactivate biologically active peptides before peptide factors access their receptors on the cell surface. Aminopeptidase A (EC 3.4.11.7), placental leucine aminopeptidase (EC 3.4.11.3), aminopeptidase‐N/CD13 (EC 3.4.11.2), dipeptidyl peptidases IV/CD26 (EC.3.4.14.5), carboxypeptidase‐M (EC 3.4.17.12), neutral endopeptidase/CD10 (EC 3.4.24.11) and endothelin converting enzyme‐1 (EC 3.4.23) are differentially expressed on the ovary, endometrium and placenta. The inhibition of enzyme activity affects steroid hormone production by granulosa and thecal cells, decidualization of endometrium and migration of extravillous trophoblasts. These findings suggest that membrane‐bound cell surface peptidases are local regulators for cellular growth and differentiation in reproductive organs by controlling extracellular concentration of peptide factors. (Reprod Med Biol 2004; 3: 165 –176) PMID:29662383

Subject standardization, acclimatization, and sample processing affect gut hormone levels and appetite in humans.

PubMed

Chandarana, Keval; Drew, Megan E; Emmanuel, Julian; Karra, Efthimia; Gelegen, Cigdem; Chan, Philip; Cron, Nicholas J; Batterham, Rachel L

2009-06-01

Gut hormones represent attractive therapeutic targets for the treatment of obesity and type 2 diabetes. However, controversy surrounds the effects that adiposity, dietary manipulations, and bariatric surgery have on their circulating concentrations. We sought to determine whether these discrepancies are due to methodologic differences. Ten normal-weight males participated in a 4-way crossover study investigating whether fasting appetite scores, plasma acyl-ghrelin, active glucagon-like peptide-1 (GLP-1), and peptide YY3-36 (PYY3-36) levels are altered by study-induced stress, prior food consumption, and sample processing. Study visit order affected anxiety, plasma cortisol, and temporal profiles of appetite and plasma PYY3-36, with increased anxiety and cortisol concentrations on the first study day. Plasma cortisol area under the curve (AUC) correlated positively with plasma PYY3-36 AUC. Despite a 14-hour fast, baseline hunger, PYY3-36 concentrations, temporal appetite profiles, PYY3-36 AUC, and active GLP-1 were affected by the previous evening's meal. Sample processing studies revealed that sample acidification and esterase inhibition are required when measuring acyl-ghrelin and dipeptidyl-peptidase IV inhibitor addition for active GLP-1. However, plasma PYY3-36 concentrations were unaffected by addition of dipeptidyl-peptidase IV. Accurate assessment of appetite, feeding behavior, and gut hormone concentrations requires standardization of prior food consumption and subject acclimatization to the study protocol. Moreover, because of the labile nature of acyl-ghrelin and active GLP-1, specialized sample processing needs to be undertaken.

Evidence for an angiotensin-(1-7) neuropeptidase expressed in the brain medulla and CSF of sheep.

PubMed

Marshall, Allyson C; Pirro, Nancy T; Rose, James C; Diz, Debra I; Chappell, Mark C

2014-07-01

Angiotensin-(1-7) [Ang-(1-7)] is an alternative product of the brain renin-angiotensin system that exhibits central actions to lower blood pressure and improve baroreflex sensitivity. We previously identified a peptidase that metabolizes Ang-(1-7) to the inactive metabolite product Ang-(1-4) in CSF of adult sheep. This study purified the peptidase 1445-fold from sheep brain medulla and characterized this activity. The peptidase was sensitive to the chelating agents o-phenanthroline and EDTA, as well as the mercury compound p-chloromercuribenzoic acid (PCMB). Selective inhibitors to angiotensin-converting enzyme, neprilysin, neurolysin, and thimet oligopeptidase did not attenuate activity; however, the metallopeptidase agent JMV-390 was a potent inhibitor of Ang-(1-7) hydrolysis (Ki = 0.8 nM). Kinetic studies using (125) I-labeled Ang-(1-7), Ang II, and Ang I revealed comparable apparent Km values (2.6, 2.8, and 4.3 μM, respectively), but a higher apparent Vmax for Ang-(1-7) (72 vs. 30 and 6 nmol/min/mg, respectively; p < 0.01). HPLC analysis of the activity confirmed the processing of unlabeled Ang-(1-7) to Ang-(1-4) by the peptidase, but revealed < 5% hydrolysis of Ang II or Ang I, and no hydrolysis of neurotensin, bradykinin or apelin-13. The unique characteristics of the purified neuropeptidase may portend a novel pathway to influence actions of Ang-(1-7) within the brain. Angiotensin-(1-7) actions are mediated by the AT7 /Mas receptor and include reduced blood pressure, decreased oxidative stress, enhanced baroreflex sensitivity, and increased nitric oxide (NO). Ang-(1-7) is directly formed from Ang I by neprilysin (NEP). We identify a new pathway for Ang-(1-7) metabolism in the brain distinct from angiotensin-converting enzyme-dependent hydrolysis. The Ang-(1-7) endopeptidase (A7-EP) degrades the peptide to Ang-(1-4) and may influence central Ang-(1-7) tone. © 2014 International Society for Neurochemistry.

Image segmentation by iterative parallel region growing with application to data compression and image analysis

NASA Technical Reports Server (NTRS)

Tilton, James C.

1988-01-01

Image segmentation can be a key step in data compression and image analysis. However, the segmentation results produced by most previous approaches to region growing are suspect because they depend on the order in which portions of the image are processed. An iterative parallel segmentation algorithm avoids this problem by performing globally best merges first. Such a segmentation approach, and two implementations of the approach on NASA's Massively Parallel Processor (MPP) are described. Application of the segmentation approach to data compression and image analysis is then described, and results of such application are given for a LANDSAT Thematic Mapper image.

P-I class metalloproteinase from Bothrops moojeni venom is a post-proline cleaving peptidase with kininogenase activity: insights into substrate selectivity and kinetic behavior.

PubMed

Okamoto, Débora N; Kondo, Marcia Y; Oliveira, Lilian C G; Honorato, Rodrigo V; Zanphorlin, Leticia M; Coronado, Monika A; Araújo, Mariana S; da Motta, Guacyara; Veronez, Camila L; Andrade, Sheila S; Oliveira, Paulo S L; Arni, Raghuvir K; Cintra, Adelia C O; Sampaio, Suely V; Juliano, Maria A; Juliano, Luiz; Murakami, Mário T; Gouvea, Iuri E

2014-03-01

Snake venom metalloproteinases (SVMPs) belonging to P-I class are able to hydrolyze extracellular matrix proteins and coagulation factors triggering local and systemic reactions by multiple molecular mechanisms that are not fully understood. BmooMPα-I, a P-I class SMVP from Bothrops moojeni venom, was active upon neuro- and vaso-active peptides including angiotensin I, bradykinin, neurotensin, oxytocin and substance P. Interestingly, BmooMPα-I showed a strong bias towards hydrolysis after proline residues, which is unusual for most of characterized peptidases. Moreover, the enzyme showed kininogenase activity similar to that observed in plasma and cells by kallikrein. FRET peptide assays indicated a relative promiscuity at its S2-S'2 subsites, with proline determining the scissile bond. This unusual post-proline cleaving activity was confirmed by the efficient hydrolysis of the synthetic combinatorial library MCA-GXXPXXQ-EDDnp, described as resistant for canonical peptidases, only after Pro residues. Structural analysis of the tripeptide LPL complexed with BmooMPα-I, generated by molecular dynamics simulations, assisted in defining the subsites and provided the structural basis for subsite preferences such as the restriction of basic residues at the S2 subsite due to repulsive electrostatic effects and the steric impediment for large aliphatic or aromatic side chains at the S1 subsite. These new functional and structural findings provided a further understanding of the molecular mechanisms governing the physiological effects of this important class of enzymes in envenomation process. Copyright © 2014 Elsevier B.V. All rights reserved.

A 120-kDa alkaline peptidase from Trypanosoma cruzi is involved in the generation of a novel Ca(2+)-signaling factor for mammalian cells.

PubMed

Burleigh, B A; Andrews, N W

1995-03-10

Trypomastigotes, the infective stages of the intracellular parasite Trypanosoma cruzi, induce rapid and repetitive cytosolic free Ca2+ transients in fibroblasts. Buffering or depletion of intracellular free Ca2+ inhibits cell entry by trypomastigotes, indicating a role for this signaling event in invasion. We show here that the majority of the Ca(2+)-signaling activity is associated with the soluble fraction of parasites disrupted by sonication. Distinct cell types from different species are responsive to this soluble factor, and intracellular free Ca2+ transients occur rapidly and reach concentrations comparable to responses induced by thrombin and bombesin. The Ca(2+)-signaling activity does not bind concanavalin A and is strongly inhibited by a specific subset of protease inhibitors. The only detectable protease in the fractions with Ca(2+)-signaling activity is an unusual alkaline peptidase of 120 kDa, to which no function had been previously assigned. The activity of the protease and cell invasion by trypomastigotes are blocked by the same specific inhibitors that impair Ca(2+)-signaling, suggesting that the enzyme is required for generating the response leading to infection. We demonstrate that the 120-kDa peptidase is not sufficient for triggering Ca(2+)-signaling, possibly being involved in the processing of precursors present only in infective trypomastigotes. These findings indicate a biological function for a previously identified unusual protozoan protease and provide the first example of a proteolytically generated parasite factor with characteristics of a mammalian hormone.

Cystatin F Affects Natural Killer Cell Cytotoxicity

PubMed Central

Perišić Nanut, Milica; Sabotič, Jerica; Švajger, Urban; Jewett, Anahid; Kos, Janko

2017-01-01

Cystatin F is a cysteine peptidase inhibitor which, unlike other cystatin family members, is targeted to endosomal/lysosomal compartments. It is synthesized as an inactive disulfide-linked dimer which is then converted to an active monomer by proteolytic cleavage of 15 N-terminal residues. Cystatin F has been suggested to regulate the cytotoxicity of natural killer (NK) cells by inhibiting the major granzyme convertases, cathepsins C and H. To test this hypothesis, we prepared variants of cystatin F and analyzed their uptake, subcellular trafficking, and peptidase inhibition, as well as their impact on the cytotoxicity of NK-92 cells and primary NK cells. The N-glycosylation pattern is responsible for the secretion, uptake, and subcellular sorting of cystatin F in HeLa and Hek293 cells, whereas the legumain binding site had no effect on these processes. Active, N-terminally truncated, monomeric cystatin F can also be internalized by recipient cells and targeted to endo/lysosomes, affecting also cells lacking the activating peptidase. Cystatin F mutants capable of cell internalization and trafficking through the endo/lysosomal pathway significantly decreased cathepsin C and H activities, both in situ, following transfection and in trans, using conditioned media. Further, incubation of IL-2 stimulated NK-92 and primary NK cells with full-length and N-terminally truncated cystatin F mutants led to suppression of their granule-mediated cytotoxicity. This effect was most significant with the N-terminally truncated mutants. These results suggest that cystatin F can be an important mediator within tumor microenvironment affecting the cytotoxicity of NK cells and consequently antitumor immune response. PMID:29180998

Effect of acute hypoxic shock on the rat brain morphology and tripeptidyl peptidase I activity.

PubMed

Petrova, Emilia B; Dimitrova, Mashenka B; Ivanov, Ivaylo P; Pavlova, Velichka G; Dimitrova, Stella G; Kadiysky, Dimitar S

2016-06-01

Hypoxic events are known to cause substantial damage to the hippocampus, cerebellum and striatum. The impact of hypoxic shock on other brain parts is not sufficiently studied. Recent studies show that tripeptidyl peptidase I (TPPI) activity in fish is altered after a hypoxic stress pointing out at a possible enzyme involvement in response to hypoxia. Similar studies are not performed in mammals. In this work, the effect of sodium nitrite-induced acute hypoxic shock on the rat brain was studied at different post-treatment periods. Morphological changes in cerebral cortex, cerebellum, medulla oblongata, thalamus, mesencephalon and pons were assessed using silver-copper impregnation for neurodegeneration. TPPI activity was biochemically assayed and localized by enzyme histochemistry. Although less vulnerable to oxidative stress, the studied brain areas showed different histopathological changes, such as neuronal loss and tissue vacuolization, dilatation of the smallest capillaries and impairment of neuronal processes. TPPI activity was strictly regulated following the hypoxic stress. It was found to increase 12-24h post-treatment, then decreased followed by a slow process of recovery. The enzyme histochemistry revealed a temporary enzyme deficiency in all types of neurons. These findings indicate a possible involvement of the enzyme in rat brain response to hypoxic stress. Copyright © 2016 Elsevier GmbH. All rights reserved.

Involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters in neonatal rat spinal cord.

PubMed Central

Suzuki, H; Yoshioka, K; Yanagisawa, M; Urayama, O; Kurihara, T; Hosoki, R; Saito, K; Otsuka, M

1994-01-01

1. The possible involvement of enzymatic degradation in the inactivation of tachykinin neurotransmitters was examined in the spinal cord of the neonatal rat. 2. The magnitude of substance P (SP)- or neurokinin A (NKA)-evoked depolarization of a lumbar ventral root in the isolated spinal cord preparation was increased by a mixture of peptidase inhibitors, consisting of actinonin (6 microM), arphamenine B (6 microM), bestatin (10 microM), captopril (10 microM) and thiorphan (0.3 microM). The mixture augmented the response to NKA more markedly than that to SP. 3. In the isolated spinal cord-cutaneous nerve preparation, the saphenous nerve-evoked slow depolarization of the L3 ventral root was augmented by the mixture of peptidase inhibitors in the presence of naloxone (0.5 microM) but not in the presence of both naloxone and a tachykinin receptor antagonist, GR71251 (5 microM). 4. Application of capsaicin (0.5 microM) for 6 min to the spinal cord evoked an increase in the release of SP from the spinal cord. The amount of SP released was significantly augmented by the mixture of peptidase inhibitors. 5. Synaptic membrane fractions were prepared from neonatal rat spinal cords. These fractions showed degrading activities for SP and NKA and the activities were inhibited by the mixture of peptidase inhibitors. The degrading activity for NKA was higher than that for SP and the inhibitory effect of the mixture for NKA was more marked than that for SP. Although some other fractions obtained from homogenates of spinal cords showed higher degrading activities for SP, these activities were insensitive to the mixture of peptidase inhibitors.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7529113

The purification and characterisation of novel dipeptidyl peptidase IV-like activity from bovine serum.

PubMed

Buckley, Seamus J; Collins, Patrick J; O'Connor, Brendan F

2004-07-01

The discovery of a potentially novel proline-specific peptidase from bovine serum is presented which is capable of cleaving the dipeptidyl peptidase IV (DPIV) substrate Gly-Pro-MCA. The enzyme was isolated and purified with the use of Phenyl Sepharose Hydrophobic Interaction, Sephacryl S-300 Gel Filtration, and Q-Sephacryl Anion Exchange, producing an overall purification factor of 257. SDS PAGE resulted in a monomeric molecular mass of 158kDa while size exclusion chromatography generated a native molecular mass of 328kDa. The enzyme remained active over a broad pH range with a distinct preference for a neutral pH range of 7-8.5. Chromatofocusing and isoelectric focusing (IEF) revealed the enzyme's isoelectric point to be 4.74. DPIV-like activity was not inhibited by serine protease inhibitors but was by the metallo-protease inhibitors, the phenanthrolines. The enzyme was also partially inhibited by bestatin. Substrate specificity studies proved that the enzyme is capable of sequential cleavage of bovine beta-Casomorphin and Substance P. The peptidase cleaved the standard DPIV substrate, Gly-Pro-MCA with a K(M) of 38.4 microM, while Lys-Pro-MCA was hydrolysed with a K(M) of 103 microM. The DPIV-like activity was specifically inhibited by both Diprotin A and B, non-competitively, generating a K(i) of 1.4 x 10(-4) M for both inhibitors. Ile-Thiazolidide and Ile-Pyrrolidide both inhibited competitively with an inhibition constant of 3.7 x 10(-7) and 7.5 x 10(-7) M, respectively. It is concluded that bovine serum DPIV-like activity share many biochemical properties with DPIV and DPIV-like enzymes but not exclusively, suggesting that the purified peptidase may play an important novel role in bioactive oligopeptide degradation.

Synthesis, kinetic evaluation, and utilization of a biotinylated dipeptide proline diphenyl phosphonate for the disclosure of dipeptidyl peptidase IV-like serine proteases.

PubMed

Gilmore, Brendan F; Carson, Louise; McShane, Laura L; Quinn, Derek; Coulter, Wilson A; Walker, Brian

2006-08-18

In this study, we report on the synthesis, kinetic characterisation, and application of a novel biotinylated and active site-directed inactivator of dipeptidyl peptidase IV (DPP-IV). Thus, the dipeptide-derived proline diphenyl phosphonate NH(2)-Glu(biotinyl-PEG)-Pro(P)(OPh)(2) has been prepared by a combination of classical solution- and solid-phase methodologies and has been shown to be an irreversible inhibitor of porcine DPP-IV, exhibiting an over all second-order rate constant (k(i)/K(i)) for inhibition of 1.57 x 10(3) M(-1) min(-1). This value compares favourably with previously reported rates of inactivation of DPP-IV by dipeptides containing a P(1) proline diphenyl phosphonate grouping [B. Boduszek, J. Oleksyszyn, C.M. Kam, J. Selzler, R.E. Smith, J.C. Powers, Dipeptide phophonates as inhibitors of dipeptidyl peptidase IV, J. Med. Chem. 37 (1994) 3969-3976; B.F. Gilmore, J.F. Lynas, C.J. Scott, C. McGoohan, L. Martin, B. Walker, Dipeptide proline diphenyl phosphonates are potent, irreversible inhibitors of seprase (FAPalpha), Biochem, Biophys. Res. Commun. 346 (2006) 436-446.], thus demonstrating that the incorporation of the side-chain modified (N-biotinyl-3-(2-(2-(3-aminopropyloxy)-ethoxy)-ethoxy)-propyl) glutamic acid residue at the P(2) position is compatible with inhibitor efficacy. The utilisation of this probe for the detection of both purified dipeptidyl peptidase IV and the disclosure of a dipeptidyl peptidase IV-like activity from a clinical isolate of Porphyromonas gingivalis, using established electrophoretic and Western blotting techniques previously developed by our group, is also demonstrated.

High-level expression of nattokinase in Bacillus licheniformis by manipulating signal peptide and signal peptidase.

PubMed

Cai, D; Wei, X; Qiu, Y; Chen, Y; Chen, J; Wen, Z; Chen, S

2016-09-01

Nattokinase is an enzyme produced by Bacillus licheniformis and has potential to be used as a drug for treating cardiovascular disease due to its beneficial effects of preventing fibrin clots etc. However, the low activity and titre of this protein produced by B. licheniformis often hinders its application of commercial production. The aim of this work is to improve the nattokinase production by manipulating signal peptides and signal peptidases in B. licheniformis. The P43 promoter, amyL terminator and AprN target gene were used to form the nattokinase expression vector, pHY-SP-NK, which was transformed into B. licheniformis and nattokinase was expressed successfully. A library containing 81 predicted signal peptides was constructed for nattokinase expression in B. licheniformis, with the maximum activity being obtained under the signal peptide of AprE. Among four type I signal peptidases genes (sipS, sipT, sipV, sipW) in B. licheniformis, the deletion of sipV resulted in a highest decrease in nattokinase activity. Overexpression of sipV in B. licheniformis led to a nattokinase activity of 35·60 FU ml(-1) , a 4·68-fold improvement over activity produced by the initial strain. This work demonstrates the potential of B. licheniformis for industrial production of nattokinase through manipulation of signal peptides and signal peptidases expression. This study has screened the signal peptides of extracellular proteins of B. licheniformis for nattokinase production. Four kinds of Type I signal peptidases genes have been detected respectively in B. licheniformis to identify which one played the vital role for nattokinase production. This study provided a promising strain for industry production of nattokinase. © 2016 The Society for Applied Microbiology.

Hydrolysis of Sequenced β-Casein Peptides Provides New Insight into Peptidase Activity from Thermophilic Lactic Acid Bacteria and Highlights Intrinsic Resistance of Phosphopeptides

PubMed Central

Deutsch, Stéphanie-Marie; Molle, Daniel; Gagnaire, Valérie; Piot, Michel; Atlan, Danièle; Lortal, Sylvie

2000-01-01

The peptidases of thermophilic lactic acid bacteria have a key role in the proteolysis of Swiss cheeses during warm room ripening. To compare their peptidase activities toward a dairy substrate, a tryptic/chymotryptic hydrolysate of purified β-casein was used. Thirty-four peptides from 3 to 35 amino acids, including three phosphorylated peptides, constitute the β-casein hydrolysate, as shown by tandem mass spectrometry. Cell extracts prepared from Lactobacillus helveticus ITG LH1, ITG LH77, and CNRZ 32, Lactobacillus delbrueckii subsp. lactis ITG LL14 and ITG LL51, L. delbrueckii subsp. bulgaricus CNRZ 397 and NCDO 1489, and Streptococcus thermophilus CNRZ 385, CIP 102303, and TA 060 were standardized in protein. The peptidase activities were assessed with the β-casein hydrolysate as the substrate at pH 5.5 and 24°C (conditions of warm room ripening) by (i) free amino acid release, (ii) reverse-phase chromatography, and (iii) identification of undigested peptides by mass spectrometry. Regardless of strain, L. helveticus was the most efficient in hydrolyzing β-casein peptides. Interestingly, cell extracts of S. thermophilus were not able to release a significant level of free proline from the β-casein hydrolysate, which was consistent with the identification of numerous dipeptides containing proline. With the three lactic acid bacteria tested, the phosphorylated peptides remained undigested or weakly hydrolyzed indicating their high intrinsic resistance to peptidase activities. Finally, several sets of peptides differing by a single amino acid in a C-terminal position revealed the presence of at least one carboxypeptidase in the cell extracts of these species. PMID:11097915

Dipeptidyl peptidase (DP) 6 and DP10: novel brain proteins implicated in human health and disease.

PubMed

McNicholas, Kym; Chen, Tong; Abbott, Catherine A

2009-01-01

Dipeptidyl peptidase (DP) 6 and DP10 are non-enzyme members of the dipeptidyl peptidase IV family, which includes fibroblast activation protein, DP8, and DP9. DP6 and DP10 proteins have been shown to be critical components of voltage-gated potassium (Kv) channels important in determining cellular excitability. The aim of this paper was to review the research to date on DP6 and DP10 structure, expression, and functions. To date, the protein region responsible for modulating Kv4 channels has not been conclusively identified and the significance of the splice variants has not been resolved. Resolution of these issues will improve our overall knowledge of DP6 and DP10 and lead to a better understanding of their role in diseases, such as asthma and Alzheimer's disease.

Crystallization and preliminary crystallographic analysis of porcine acylaminoacyl peptidase.

PubMed

Wright, Helena; Kiss, András L; Szeltner, Zoltán; Polgár, László; Fülöp, Vilmos

2005-10-01

Acylaminoacyl peptidase (also known as acylamino-acid-releasing enzyme or acylpeptide hydrolase; EC 3.4.19.1) is an unusual member of the prolyl oligopeptidase family catalysing the hydrolysis of an N-acylated peptide to an acylamino acid and a peptide with a free N-terminus. Acylaminoacyl peptidase purified from porcine liver has been crystallized in mother liquor containing 0.1 M Tris-HCl pH 7.0, 10%(w/v) polyethylene glycol 8000, 50 mM MgCl2 and 1%(w/v) CHAPS using the hanging-drop vapour-diffusion technique. A full data set to 3.4 A resolution was collected at ESRF beamline ID14-4 and space group C222 was assigned, with unit-cell parameters a = 84.8, b = 421.1, c = 212.0 A and four molecules in the asymmetric unit.

Sliding mode controller for a photovoltaic pumping system

NASA Astrophysics Data System (ADS)

ElOugli, A.; Miqoi, S.; Boutouba, M.; Tidhaf, B.

2017-03-01

In this paper, a sliding mode control scheme (SMC) for maximum power point tracking controller for a photovoltaic pumping system, is proposed. The main goal is to maximize the flow rate for a water pump, by forcing the photovoltaic system to operate in its MPP, to obtain the maximum power that a PV system can deliver.And this, through the intermediary of a sliding mode controller to track and control the MPP by overcoming the power oscillation around the operating point, which appears in most implemented MPPT techniques. The sliding mode control approach is recognized as one of the efficient and powerful tools for nonlinear systems under uncertainty conditions.The proposed controller with photovoltaic pumping system is designed and simulated using MATLAB/SIMULINK environment. In addition, to evaluate its performances, a classical MPPT algorithm using perturb and observe (P&O) has been used for the same system to compare to our controller. Simulation results are shown.

A New MPPT Control for Photovoltaic Panels by Instantaneous Maximum Power Point Tracking

NASA Astrophysics Data System (ADS)

Tokushima, Daiki; Uchida, Masato; Kanbei, Satoshi; Ishikawa, Hiroki; Naitoh, Haruo

This paper presents a new maximum power point tracking control for photovoltaic (PV) panels. The control can be categorized into the Perturb and Observe (P & O) method. It utilizes instantaneous voltage ripples at PV panel output terminals caused by the switching of a chopper connected to the panel in order to identify the direction for the maximum power point (MPP). The tracking for the MPP is achieved by a feedback control of the average terminal voltage of the panel. Appropriate use of the instantaneous and the average values of the PV voltage for the separate purposes enables both the quick transient response and the good convergence with almost no ripples simultaneously. The tracking capability is verified experimentally with a 2.8 W PV panel under a controlled experimental setup. A numerical comparison with a conventional P & O confirms that the proposed control extracts much more power from the PV panel.

1-Ethyl-1-methyl piperidinium bis(trifluoromethanesulfonyl)imide as a co-solvent in Li-ion batteries

NASA Astrophysics Data System (ADS)

Kim, Ketack; Cho, Young-Hyun; Shin, Heon-Cheol

2013-03-01

1-Ethyl-1-methyl piperidinium bis(trifluoromethanesulfonyl)imide (EMP-TFSI) is an ionic liquid with a melting temperature of 85 °C. Although it is a solid salt, it shows good miscibility with carbonate solvents, which allows EMP-TFSI to be used as a co-solvent in these systems. Ethylene carbonate is another solid co-solvent used in Li-ion batteries. Due to its smaller cationic size, EMP-TFSI provides better conductivity as a co-solvent than 1-methyl-1-propyl piperidinium bis(trifluoromethanesulfonyl)imide (MPP-TFSI), which is the smallest room-temperature piperidinium liquid salt known. In cells with 50 wt% IL and 50 wt% carbonate electrolyte, an EMP-TFSI mixed electrolyte performs better than an MPP-TFSI mixed electrolyte. Additionally, the discharge capacity values obtained from rate capability tests carried out with mixed EMP-TFSI are as good as those conducted with a pure carbonate electrolyte.

Taurine-induced attenuation of MPP+ neurotoxicity in vitro: a possible role for the GABA(A) subclass of GABA receptors.

PubMed

O'Byrne, M B; Tipton, K F

2000-05-01

Taurine is a sulphur-containing beta-amino acid found in high (millimolar) concentrations in excitable tissues such as brain and heart. Its suggested roles include osmoregulator, thermoregulator, neuromodulator, and potential neurotransmitter. This amino acid has also been shown to be released in large concentrations during ischaemia and excitotoxin-induced neuronal damage. Here we report a protective effect of taurine against MPP(+)-induced neurotoxicity in coronal slices from rat brain. Significant protective effects were observed at taurine concentrations of 20 and 1 mM, suggesting a potential role for taurine in cases of neuronal insult. Studies with the synthetic taurine analogues taurine phosphonate, guanidinoethane sulphonate, and trimethyltaurine suggested the observed effect to be mediated via an extracellular mechanism. The use of GABA receptor ligands muscimol and bicuculline indicated the effect to be mediated through activation of GABA(A) receptors.

Maximum Power Point tracking charge controllers for telecom applications -- Analysis and economics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wills, R.H.

Simple charge controllers connect photovoltaic modules directly to the battery bank resulting in a significant power loss if the battery bank voltage differs greatly from the PV Maximum Power Point (MPP) voltage. Recent modeling work at AES has shown that dc-dc converter type MPP tracking charge controllers can deliver more than 30% more energy from PV modules to the battery when the PV modules are cool and the battery state of charge is low--this is typically both the worst case condition (i.e., winter) and also the design condition that determines the PV array size. Economic modeling, based on typical telecommore » system installed costs shows benefits of more than $3/Wp for MPPT over conventional charge controllers in this application--a value that greatly exceeds the additional cost of the dc-dc converter.« less

Implementation of an ADI method on parallel computers

NASA Technical Reports Server (NTRS)

Fatoohi, Raad A.; Grosch, Chester E.

1987-01-01

The implementation of an ADI method for solving the diffusion equation on three parallel/vector computers is discussed. The computers were chosen so as to encompass a variety of architectures. They are: the MPP, an SIMD machine with 16K bit serial processors; FLEX/32, an MIMD machine with 20 processors; and CRAY/2, an MIMD machine with four vector processors. The Gaussian elimination algorithm is used to solve a set of tridiagonal systems on the FLEX/32 and CRAY/2 while the cyclic elimination algorithm is used to solve these systems on the MPP. The implementation of the method is discussed in relation to these architectures and measures of the performance on each machine are given. Simple performance models are used to describe the performance. These models highlight the bottlenecks and limiting factors for this algorithm on these architectures. Finally, conclusions are presented.

Implementation of an ADI method on parallel computers

NASA Technical Reports Server (NTRS)

Fatoohi, Raad A.; Grosch, Chester E.

1987-01-01

In this paper the implementation of an ADI method for solving the diffusion equation on three parallel/vector computers is discussed. The computers were chosen so as to encompass a variety of architectures. They are the MPP, an SIMD machine with 16-Kbit serial processors; Flex/32, an MIMD machine with 20 processors; and Cray/2, an MIMD machine with four vector processors. The Gaussian elimination algorithm is used to solve a set of tridiagonal systems on the Flex/32 and Cray/2 while the cyclic elimination algorithm is used to solve these systems on the MPP. The implementation of the method is discussed in relation to these architectures and measures of the performance on each machine are given. Simple performance models are used to describe the performance. These models highlight the bottlenecks and limiting factors for this algorithm on these architectures. Finally conclusions are presented.

Protection of Primary Dopaminergic Midbrain Neurons by GPR139 Agonists Supports Different Mechanisms of MPP+ and Rotenone Toxicity

PubMed Central

Bayer Andersen, Kirsten; Leander Johansen, Jens; Hentzer, Morten; Smith, Garrick Paul; Dietz, Gunnar P. H.

2016-01-01

The G-protein coupled receptor 139 (GPR139) is expressed specifically in the brain in areas of relevance for motor control. GPR139 function and signal transduction pathways are elusive, and results in the literature are even contradictory. Here, we examined the potential neuroprotective effect of GPR139 agonism in primary culture models of dopaminergic (DA) neuronal degeneration. We find that in vitro GPR139 agonists protected primary mesencephalic DA neurons against 1-methyl-4-phenylpyridinium (MPP+)-mediated degeneration. Protection was concentration-dependent and could be blocked by a GPR139 antagonist. However, the protection of DA neurons was not found against rotenone or 6-hydroxydopamine (6-OHDA) mediated degeneration. Our results support differential mechanisms of toxicity for those substances commonly used in Parkinson’s disease (PD) models and potential for GPR139 agonists in neuroprotection. PMID:27445691

Interactions of "bora-penicilloates" with serine β-lactamases and DD-peptidases.

PubMed

Dzhekieva, Liudmila; Adediran, S A; Pratt, R F

2014-10-21

Specific boronic acids are generally powerful tetrahedral intermediate/transition state analogue inhibitors of serine amidohydrolases. This group of enzymes includes bacterial β-lactamases and DD-peptidases where there has been considerable development of boronic acid inhibitors. This paper describes the synthesis, determination of the inhibitory activity, and analysis of the results from two α-(2-thiazolidinyl) boronic acids that are closer analogues of particular tetrahedral intermediates involved in β-lactamase and DD-peptidase catalysis than those previously described. One of them, 2-[1-(dihydroxyboranyl)(2-phenylacetamido)methyl]-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid, is a direct analogue of the deacylation tetrahedral intermediates of these enzymes. These compounds are micromolar inhibitors of class C β-lactamases but, very unexpectedly, not inhibitors of class A β-lactamases. We rationalize the latter result on the basis of a new mechanism of boronic acid inhibition of the class A enzymes. A stable inhibitory complex is not accessible because of the instability of an intermediate on its pathway of formation. The new boronic acids also do not inhibit bacterial DD-peptidases (penicillin-binding proteins). This result strongly supports a central feature of a previously proposed mechanism of action of β-lactam antibiotics, where deacylation of β-lactam-derived acyl-enzymes is not possible because of unfavorable steric interactions.

Structural and Molecular Basis for the Novel Catalytic Mechanism and Evolution of DddP, an Abundant Peptidase-Like Bacterial Dimethylsulfoniopropionate Lyase: A New Enzyme from an Old Fold

NASA Astrophysics Data System (ADS)

Zhang, Y. Z.; Wang, P.; Chen, X. L.; Li, C. Y.; Gao, X.; Zhu, D.; Xie, B. B.; Qin, Q. L.; Zhang, X. Y.; Su, H. N.; Zhou, B. C.; Xun, L.

2015-12-01

The microbial cleavage of dimethylsulfoniopropionate (DMSP) generates volatile dimethyl sulfide (DMS) and is an important step in global sulfur and carbon cycles. DddP is a DMSP lyase in marine bacteria and the deduced dddP gene product is abundant in marine metagenomic data sets. However, DddP belongs to the M24 peptidase family according to sequence alignment. Peptidases hydrolyze C-N bonds but DddP is deduced to cleave C-S bonds. Mechanisms responsible for this striking functional shift are currently unknown. We determined the structures of DMSP lyase RlDddP (the DddP from Ruegeria lacuscaerulensis ITI_1157) bound to inhibitory 2-(N-morpholino) ethanesulfonic acid or PO43- and of two mutants of RlDddP bound to acrylate. Based on structural, mutational and biochemical analyses, we characterized a new ion-shift catalytic mechanism of RlDddP for DMSP cleavage. Further, we suggested the structural mechanism leading to the loss of peptidase activity and the subsequent development of DMSP lyase activity in DddP. This study sheds light on the catalytic mechanism and the divergent evolution of DddP, leading to a better understanding of marine bacterial DMSP catabolism and global DMS production.

Bursaphelenchus xylophilus and B. mucronatus secretomes: a comparative proteomic analysis

PubMed Central

Cardoso, Joana M. S.; Anjo, Sandra I.; Fonseca, Luís; Egas, Conceição; Manadas, Bruno; Abrantes, Isabel

2016-01-01

The pinewood nematode, Bursaphelenchus xylophilus, recognized as a worldwide major forest pest, is a migratory endoparasitic nematode with capacity to feed on pine tissues and also on fungi colonizing the trees. Bursaphelenchus mucronatus, the closest related species, differs from B. xylophilus on its pathogenicity, making this nematode a good candidate for comparative analyses. Secretome profiles of B. xylophilus and B. mucronatus were obtained and proteomic differences were evaluated by quantitative SWATH-MS. From the 681 proteins initially identified, 422 were quantified and compared between B. xylophilus and B. mucronatus secretomes and from these, 243 proteins were found differentially regulated: 158 and 85 proteins were increased in B. xylophilus and B. mucronatus secretomes, respectively. While increased proteins in B. xylophilus secretome revealed a strong enrichment in proteins with peptidase activity, the increased proteins in B. mucronatus secretome were mainly related to oxidative stress responses. The changes in peptidases were evaluated at the transcription level by RT-qPCR, revealing a correlation between the mRNA levels of four cysteine peptidases with secretion levels. The analysis presented expands our knowledge about molecular basis of B. xylophilus and B. mucronatus hosts interaction and supports the hypothesis of a key role of secreted peptidases in B. xylophilus pathogenicity. PMID:27941947

Inhibitors of tripeptidyl peptidase II. 3. Derivation of butabindide by successive structure optimizations leading to a potential general approach to designing exopeptidase inhibitors.

PubMed

Ganellin, C Robin; Bishop, Paul B; Bambal, Ramesh B; Chan, Suzanne M T; Leblond, Bertrand; Moore, Andrew N J; Zhao, Lihua; Bourgeat, Pierre; Rose, Christiane; Vargas, Froylan; Schwartz, Jean-Charles

2005-11-17

The cholecystokinin-8 (CCK-8)-inactivating peptidase is a serine peptidase that has been shown to be a membrane-bound isoform of tripeptidyl peptidase II (EC 3.4.14.10). It cleaves the neurotransmitter CCK-8 sulfate at the Met-Gly bond to give Asp-Tyr(SO3H)-Met-OH + Gly-Trp-Met-Asp-Phe-NH2. Starting from Val-Pro-NHBu, a dipeptide of submicromolar affinity that had previously been generated to serve as a lead, successive optimization at P3, P1, and then P2 gave Abu-Pro-NHBu (18, Ki = 80 nM). Further transformation (by making a benzologue) gave the indoline analogue, butabindide (33) as a reversible inhibitor having nanomolar affinity (Ki = 7 nM). Retrospective analysis suggested the possibility of a general approach to designing exopeptidase inhibitors starting from the structure of the first hydrolysis product. Application of this approach to CCK-8 led to Abu-Phe-NHBu (37), but this only had Ki = 9.4 microM. Molecular modeling, to determine the minimum energy conformations and explain the 1000-fold better affinity of butabindide, indicated that 37 cannot access the likely active conformation of butabindide.

Optimal Reference Gene Selection for Expression Studies in Human Reticulocytes.

PubMed

Aggarwal, Anu; Jamwal, Manu; Viswanathan, Ganesh K; Sharma, Prashant; Sachdeva, ManUpdesh S; Bansal, Deepak; Malhotra, Pankaj; Das, Reena

2018-05-01

Reference genes are indispensable for normalizing mRNA levels across samples in real-time quantitative PCR. Their expression levels vary under different experimental conditions and because of several inherent characteristics. Appropriate reference gene selection is thus critical for gene-expression studies. This study aimed at selecting optimal reference genes for gene-expression analysis of reticulocytes and at validating them in hereditary spherocytosis (HS) and β-thalassemia intermedia (βTI) patients. Seven reference genes (PGK1, MPP1, HPRT1, ACTB, GAPDH, RN18S1, and SDHA) were selected because of published reports. Real-time quantitative PCR was performed on reticulocytes in 20 healthy volunteers, 15 HS patients, and 10 βTI patients. Threshold cycle values were compared with fold-change method and RefFinder software. The stable reference genes recommended by RefFinder were validated with SLC4A1 and flow cytometric eosin-5'-maleimide binding assay values in HS patients and HBG2 and high performance liquid chromatography-derived percentage of hemoglobin F in βTI. Comprehensive ranking predicted MPP1 and GAPDH as optimal reference genes for reticulocytes that were not affected in HS and βTI. This was further confirmed on validation with eosin-5'-maleimide results and percentage of hemoglobin F in HS and βTI patients, respectively. Hence, MPP1 and GAPDH are good reference genes for reticulocyte expression studies compared with ACTB and RN18S1, the two most commonly used reference genes. Copyright © 2018 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

G2019S LRRK2 mutant fibroblasts from Parkinson's disease patients show increased sensitivity to neurotoxin 1-methyl-4-phenylpyridinium dependent of autophagy.

PubMed

Yakhine-Diop, Sokhna M S; Bravo-San Pedro, José M; Gómez-Sánchez, Rubén; Pizarro-Estrella, Elisa; Rodríguez-Arribas, Mario; Climent, Vicente; Aiastui, Ana; López de Munain, Adolfo; Fuentes, José M; González-Polo, Rosa A

2014-10-03

Parkinson's disease (PD) is a neurodegenerative disorder of unknown etiology. It is considered as a multifactorial disease dependent on environmental and genetic factors. Deregulation in cell degradation has been related with a significant increase in cell damage, becoming a target for studies on the PD etiology. In the present study, we have characterized the parkinsonian toxin 1-methyl-4-phenylpyridinium ion (MPP(+))-induced damage in fibroblasts from Parkinson's patients with the mutation G2019S in leucine-rich repeat kinase 2 protein (LRRK2) and control individuals without this mutation. The results reveal that MPP(+) induces mTOR-dependent autophagy in fibroblasts. Moreover, the effects of caspase-dependent cell death to MPP(+) were higher in cells with the G2019S LRRK2 mutation, which showed basal levels of autophagy due to the G2019S LRRK2 mutation (mTOR-independent). The inhibition of autophagy by 3-methyladenine (3-MA) treatment reduces these sensitivity differences between both cell types, however, the inhibition of autophagosome-lysosome fusion by bafilomycin A1 (Baf A1) increases these differences. This data confirm the importance of the combination of genetic and environmental factors in the PD etiology. Thereby, the sensitivity to the same damage may be different in function of a genetic predisposition, reason why individuals with certain mutations can develop some early-onset diseases, such as individuals with G2019S LRRK2 mutation and PD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Protection of dopaminergic neurons by 5-lipoxygenase inhibitor.

PubMed

Kang, Kai-Hsiang; Liou, Horng-Hui; Hour, Mann-Jen; Liou, Houng-Chi; Fu, Wen-Mei

2013-10-01

Neuroinflammation and oxidative stress are important factors that induce neurodegeneration in age-related neurological disorders. 5-Lipoxygenase (5-LOX) is the enzyme responsible for catalysing the synthesis of leukotriene or 5-HETE from arachidonic acid. 5-LOX is expressed in the central nervous system and may cause neurodegenerative disease. In this study, we investigated the effect of the pharmacological inhibition of 5-lipoxygenase on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/MPP(+)-induced dopaminergic neuronal death in midbrain neuron-glia co-cultures and in mice. It was found that 5-LOX was over-expressed in astrocytes after the injection of MPTP into C57BL6 mice. MK-886, a specific inhibitor of 5-LOX activating protein (FLAP), significantly increased [(3)H]-dopamine uptake, a functional indicator of the integrity of dopaminergic neurons, in midbrain cultures or the SH-SY5Y human dopaminergic cell line following MPP(+) treatment. In addition, LTB₄, one of 5-LOX's downstream products, was increased in the striatum and substantia nigra following MPTP injection in mice. LTB₄ but not LTD₄ and 5-HETE enhanced MPP(+)-induced neurotoxicity in primary midbrain cultures. MK-886 administration increased the number of tyrosine hydroxylase-positive neurons in the substantia nigra and the dopamine content in the striatum in MPTP-induced parkinsonian mice. Furthermore, the MPTP-induced upregulation of LTB₄ in the striatum and substantia nigra was antagonised by MK-886. These results suggest that 5-LOX inhibitors may be developed as novel neuroprotective agents and LTB₄ may play an important pathological role in Parkinson's disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

3-(Fur-2-yl)-10-(2-phenylethyl)-[1,2,4]triazino[4,3-a]benzimidazol-4(10H)-one, a novel adenosine receptor antagonist with A(2A)-mediated neuroprotective effects.

PubMed

Scatena, Alessia; Fornai, Francesco; Trincavelli, Maria Letizia; Taliani, Sabrina; Daniele, Simona; Pugliesi, Isabella; Cosconati, Sandro; Martini, Claudia; Da Settimo, Federico

2011-09-21

In this study, compound FTBI (3-(2-furyl)-10-(2-phenylethyl)[1,2,4]triazino[4,3-a]benzimidazol-4(10H)-one) was selected from a small library of triazinobenzimidazole derivatives as a potent A(2A) adenosine receptor (AR) antagonist and tested for its neuroprotective effects against two different kinds of dopaminergic neurotoxins, 1-methyl-4-phenylpyridinium (MPP+) and methamphetamine (METH), in rat PC12 and in human neuroblastoma SH-SY5Y cell lines. FTBI, in a concentration range corresponding to its affinity for A(2A) AR subtype, significantly increased the number of viable PC12 cells after their exposure to METH and, to a similar extent, to MPP+, as demonstrated in both trypan blue exclusion assay and in cytological staining. These neuroprotective effects were also observed with a classical A(2A) AR antagonist, ZM241385, and appeared to be completely counteracted by the AR agonist, NECA, supporting A(2A) ARs are directly involved in FTBI-mediated effects. Similarly, in human SH-SY5Y cells, FTBI was able to prevent cell toxicity induced by MPP+ and METH, showing that this A(2A) AR antagonist has a neuroprotective effect independently by the specific cell model. Altogether these results demonstrate that the A(2A) AR blockade mediates cell protection against neurotoxicity induced by dopaminergic neurotoxins in dopamine containing cells, supporting the potential use of A(2A) AR antagonists in dopaminergic degenerative diseases including Parkinson's disease.

Protocol for a nationwide survey of primary health care in China: the China PEACE (Patient-centered Evaluative Assessment of Cardiac Events) MPP (Million Persons Project) Primary Health Care Survey

PubMed Central

Su, Meng; Zhang, Qiuli; Lu, Jiapeng; Li, Xi; Tian, Na; Wang, Yun; Yip, Winnie; Cheng, Kar Keung; Mensah, George A; Horwitz, Ralph I; Mossialos, Elias; Krumholz, Harlan M; Jiang, Lixin

2017-01-01

Introduction China has pioneered advances in primary health care (PHC) and public health for a large and diverse population. To date, the current state of PHC in China has not been subjected to systematic assessments. Understanding variations in primary care services could generate opportunities for improving the structure and function of PHC. Methods and analysis This paper describes a nationwide PHC study (PEACE MPP Primary Health Care Survey) conducted across 31 provinces in China. The study leverages an ongoing research project, the China Patient-centered Evaluative Assessment of Cardiac Events (PEACE) Million Persons Project (MPP). It employs an observational design with document acquisition and abstraction and in-person interviews. The study will collect data and original documents on the structure and financing of PHC institutions and the adequacy of the essential medicines programme; the education, training and retention of the PHC workforce; the quality of care; and patient satisfaction with care. The study will provide a comprehensive assessment of current PHC services and help determine gaps in access and quality of care. All study instruments and documents will be deposited in the Document Bank as an open-access source for other researchers. Ethics and dissemination The central ethics committee at the China National Centre for Cardiovascular Disease (NCCD) approved the study. Written informed consent has been obtained from all patients. Findings will be disseminated in future peer reviewed papers, and will inform strategies aimed at improving the PHC in China. Trial registration number NCT02953926 PMID:28851781

Structure of human dipeptidyl peptidase I (cathepsin C): exclusion domain added to an endopeptidase framework creates the machine for activation of granular serine proteases

PubMed Central

Turk, Dušan; Janjić, Vojko; Štern, Igor; Podobnik, Marjetka; Lamba, Doriano; Weis Dahl, Søren; Lauritzen, Connie; Pedersen, John; Turk, Vito; Turk, Boris

2001-01-01

Dipeptidyl peptidase I (DPPI) or cathepsin C is the physiological activator of groups of serine proteases from immune and inflammatory cells vital for defense of an organism. The structure presented shows how an additional domain transforms the framework of a papain-like endopeptidase into a robust oligomeric protease-processing enzyme. The tetrahedral arrangement of the active sites exposed to solvent allows approach of proteins in their native state; the massive body of the exclusion domain fastened within the tetrahedral framework excludes approach of a polypeptide chain apart from its termini; and the carboxylic group of Asp1 positions the N-terminal amino group of the substrate. Based on a structural comparison and interactions within the active site cleft, it is suggested that the exclusion domain originates from a metallo-protease inhibitor. The location of missense mutations, characterized in people suffering from Haim–Munk and Papillon–Lefevre syndromes, suggests how they disrupt the fold and function of the enzyme. PMID:11726493

Discovery of novel transcripts of the human tissue kallikrein (KLK1) and kallikrein-related peptidase 2 (KLK2) in human cancer cells, exploiting Next-Generation Sequencing technology.

PubMed

Adamopoulos, Panagiotis G; Kontos, Christos K; Scorilas, Andreas

2018-03-31

Tissue kallikrein, kallikrein-related peptidases (KLKs), and plasma kallikrein form the largest group of serine proteases in the human genome, sharing many structural and functional properties. Several KLK transcripts have been found aberrantly expressed in numerous human malignancies, confirming their prognostic or/and diagnostic values. However, the process of alternative splicing can now be studied in-depth due to the development of Next-Generation Sequencing (NGS). In the present study, we used NGS to discover novel transcripts of the KLK1 and KLK2 genes, after nested touchdown PCR. Bioinformatics analysis and PCR experiments revealed a total of eleven novel KLK transcripts (two KLK1 and nine KLK2 transcripts). In addition, the expression profiles of each novel transcript were investigated with nested PCR experiments using variant-specific primers. Since KLKs are implicated in human malignancies, qualifying as potential biomarkers, the quantification of the presented novel transcripts in human samples may have clinical applications in different types of cancer. Copyright © 2018. Published by Elsevier Inc.

Heat shock protein 60: an endogenous inducer of dopaminergic cell death in Parkinson disease

PubMed Central

2014-01-01

Background Increasing evidence suggests that inflammation associated with microglial cell activation in the substantia nigra (SN) of patients with Parkinson disease (PD) is not only a consequence of neuronal degeneration, but may actively sustain dopaminergic (DA) cell loss over time. We aimed to study whether the intracellular chaperone heat shock protein 60 (Hsp60) could serve as a signal of CNS injury for activation of microglial cells. Methods Hsp60 mRNA expression in the mesencephalon and the striatum of C57/BL6 mice treated with MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) and the Hsp60/TH mRNA ratios in the SN of PD patients and aged-matched subjects were measured. To further investigate a possible link between the neuronal Hsp60 response and PD-related cellular stress, Hsp60 immunoblot analysis and quantification in cell lysates from SH-SY5Y after treatment with 100 μM MPP+ (1-methyl-4-phenylpyridinium) at different time points (6, 12, 24 and 48 hours) compared to control cells were performed. Additional MTT and LDH assay were used. We next addressed the question as to whether Hsp60 influences the survival of TH+ neurons in mesencephalic neuron-glia cultures treated either with MPP+ (1 μM), hHsp60 (10 μg/ml) or a combination of both. Finally, we measured IL-1β, IL-6, TNF-α and NO-release by ELISA in primary microglial cell cultures following treatment with different hHsp60 preparations. Control cultures were exposed to LPS. Results In the mesencephalon and striatum of mice treated with MPTP and also in the SN of PD patients, we found that Hsp60 mRNA was up-regulated. MPP+, the active metabolite of MPTP, also caused an increased expression and release of Hsp60 in the human dopaminergic cell line SH-SY5Y. Interestingly, in addition to being toxic to DA neurons in primary mesencephalic cultures, exogenous Hsp60 aggravated the effects of MPP+. Yet, although we demonstrated that Hsp60 specifically binds to microglial cells, it failed to stimulate the production of pro-inflammatory cytokines or NO by these cells. Conclusions Overall, our data suggest that Hsp60 is likely to participate in DA cell death in PD but via a mechanism unrelated to cytokine release. PMID:24886419

Small amounts of tissue preserve pancreatic function: Long-term follow-up study of middle-segment preserving pancreatectomy.

PubMed

Lu, Zipeng; Yin, Jie; Wei, Jishu; Dai, Cuncai; Wu, Junli; Gao, Wentao; Xu, Qing; Dai, Hao; Li, Qiang; Guo, Feng; Chen, Jianmin; Xi, Chunhua; Wu, Pengfei; Zhang, Kai; Jiang, Kuirong; Miao, Yi

2016-11-01

Middle-segment preserving pancreatectomy (MPP) is a novel procedure for treating multifocal lesions of the pancreas while preserving pancreatic function. However, long-term pancreatic function after this procedure remains unclear.The aims of this current study are to investigate short- and long-term outcomes, especially long-term pancreatic endocrine function, after MPP.From September 2011 to December 2015, 7 patients underwent MPP in our institution, and 5 cases with long-term outcomes were further analyzed in a retrospective manner. Percentage of tissue preservation was calculated using computed tomography volumetry. Serum insulin and C-peptide levels after oral glucose challenge were evaluated in 5 patients. Beta-cell secreting function including modified homeostasis model assessment of beta-cell function (HOMA2-beta), area under the curve (AUC) for C-peptide, and C-peptide index were evaluated and compared with those after pancreaticoduodenectomy (PD) and total pancreatectomy. Exocrine function was assessed based on questionnaires.Our case series included 3 women and 2 men, with median age of 50 (37-81) years. Four patients underwent pylorus-preserving PD together with distal pancreatectomy (DP), including 1 with spleen preserved. The remaining patient underwent Beger procedure and spleen-preserving DP. Median operation time and estimated intraoperative blood loss were 330 (250-615) min and 800 (400-5500) mL, respectively. Histological examination revealed 3 cases of metastatic lesion to the pancreas, 1 case of chronic pancreatitis, and 1 neuroendocrine tumor. Major postoperative complications included 3 cases of delayed gastric emptying and 2 cases of postoperative pancreatic fistula. Imaging studies showed that segments representing 18.2% to 39.5% of the pancreas with good blood supply had been preserved. With a median 35.0 months of follow-ups on pancreatic functions, only 1 patient developed new-onset diabetes mellitus of the 4 preoperatively euglycemic patients. Beta-cell function parameters in this group of patients were quite comparable to those after Whipple procedure, and seemed better than those after total pancreatectomy. No symptoms of hypoglycemia were identified in any patient, although half of the patients reported symptoms of exocrine insufficiency.In conclusion, MPP is a feasible and effective procedure for middle-segment sparing multicentric lesions in the pancreas, and patients exhibit satisfied endocrine function after surgery.

Small amounts of tissue preserve pancreatic function

PubMed Central

Lu, Zipeng; Yin, Jie; Wei, Jishu; Dai, Cuncai; Wu, Junli; Gao, Wentao; Xu, Qing; Dai, Hao; Li, Qiang; Guo, Feng; Chen, Jianmin; Xi, Chunhua; Wu, Pengfei; Zhang, Kai; Jiang, Kuirong; Miao, Yi

2016-01-01

Abstract Middle-segment preserving pancreatectomy (MPP) is a novel procedure for treating multifocal lesions of the pancreas while preserving pancreatic function. However, long-term pancreatic function after this procedure remains unclear. The aims of this current study are to investigate short- and long-term outcomes, especially long-term pancreatic endocrine function, after MPP. From September 2011 to December 2015, 7 patients underwent MPP in our institution, and 5 cases with long-term outcomes were further analyzed in a retrospective manner. Percentage of tissue preservation was calculated using computed tomography volumetry. Serum insulin and C-peptide levels after oral glucose challenge were evaluated in 5 patients. Beta-cell secreting function including modified homeostasis model assessment of beta-cell function (HOMA2-beta), area under the curve (AUC) for C-peptide, and C-peptide index were evaluated and compared with those after pancreaticoduodenectomy (PD) and total pancreatectomy. Exocrine function was assessed based on questionnaires. Our case series included 3 women and 2 men, with median age of 50 (37–81) years. Four patients underwent pylorus-preserving PD together with distal pancreatectomy (DP), including 1 with spleen preserved. The remaining patient underwent Beger procedure and spleen-preserving DP. Median operation time and estimated intraoperative blood loss were 330 (250–615) min and 800 (400–5500) mL, respectively. Histological examination revealed 3 cases of metastatic lesion to the pancreas, 1 case of chronic pancreatitis, and 1 neuroendocrine tumor. Major postoperative complications included 3 cases of delayed gastric emptying and 2 cases of postoperative pancreatic fistula. Imaging studies showed that segments representing 18.2% to 39.5% of the pancreas with good blood supply had been preserved. With a median 35.0 months of follow-ups on pancreatic functions, only 1 patient developed new-onset diabetes mellitus of the 4 preoperatively euglycemic patients. Beta-cell function parameters in this group of patients were quite comparable to those after Whipple procedure, and seemed better than those after total pancreatectomy. No symptoms of hypoglycemia were identified in any patient, although half of the patients reported symptoms of exocrine insufficiency. In conclusion, MPP is a feasible and effective procedure for middle-segment sparing multicentric lesions in the pancreas, and patients exhibit satisfied endocrine function after surgery. PMID:27861351

Production of wheat gluten hydrolysates with reduced antigenicity employing enzymatic hydrolysis combined with downstream unit operations.

PubMed

Merz, Michael; Kettner, Lucas; Langolf, Emma; Appel, Daniel; Blank, Imre; Stressler, Timo; Fischer, Lutz

2016-08-01

Due to allergies or other health disorders a certain segment of the population is not able to safely consume some plant proteins, which are the main protein support in human nutrition. Coeliac disease is a prominent autoimmune disorder and requires a strict adherence to a gluten-free diet. The aim of this study was to identify suitable combinations of enzymatic hydrolysis and common unit operations in food processing (centrifugation, ultra-filtration) to produce gluten-free wheat gluten hydrolysates for food application. To analyse the hydrolysates, a simple and cheap competitive ELISA protocol was designed and validated in this study as well. The competitive ELISA was validated using gliadin spiked skim milk protein hydrolysates, due to the latter application of the assay. The limit of quantification was 4.19 mg kg(-1) , which allowed the identification of gluten-free (<20 mg kg(-1) ) hydrolysates. Enzymatic hydrolysis, including the type of peptidase, and the downstream processing greatly affected the antigenicity of the hydrolysates. Enzymatic hydrolysis and downstream processing operations, such as centrifugation and ultra-filtration, reduced the antigenicity of wheat gluten hydrolysates. Gluten-free hydrolysates were obtained with Flavourzyme after centrifugation (25 g L(-1) substrate) and after 1 kDa ultra-filtration (100 g L(-1) substrate). A multiple peptidase complex, such as Flavourzyme, seems to be required for the production of gluten-free hydrolysates. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

(2R)-4-Oxo-4[3-(Trifluoromethyl)-5,6-diihydro:1,2,4}triazolo[4,3-a}pyrazin-7(8H)-y1]-1-(2,4,5-trifluorophenyl)butan-2-amine: A Potent, Orally Active Dipeptidyl Peptidase IV Inhibitor for the Treatment of Type 2 Diabetes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, D.; Wang, L.; Beconi, M.

2010-11-10

A novel series of {beta}-amino amides incorporating fused heterocycles, i.e., triazolopiperazines, were synthesized and evaluated as inhibitors of dipeptidyl peptidase IV (DPP-IV) for the treatment of type 2 diabetes. (2R)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine (1) is a potent, orally active DPP-IV inhibitor (IC{sub 50} = 18 nM) with excellent selectivity over other proline-selective peptidases, oral bioavailability in preclinical species, and in vivo efficacy in animal models. MK-0431, the phosphate salt of compound 1, was selected for development as a potential new treatment for type 2 diabetes.

Discovery, structure-activity relationship, and pharmacological evaluation of (5-substituted-pyrrolidinyl-2-carbonyl)-2-cyanopyrrolidines as potent dipeptidyl peptidase IV inhibitors.

PubMed

Pei, Zhonghua; Li, Xiaofeng; Longenecker, Kenton; von Geldern, Thomas W; Wiedeman, Paul E; Lubben, Thomas H; Zinker, Bradley A; Stewart, Kent; Ballaron, Stephen J; Stashko, Michael A; Mika, Amanda K; Beno, David W A; Long, Michelle; Wells, Heidi; Kempf-Grote, Anita J; Madar, David J; McDermott, Todd S; Bhagavatula, Lakshmi; Fickes, Michael G; Pireh, Daisy; Solomon, Larry R; Lake, Marc R; Edalji, Rohinton; Fry, Elizabeth H; Sham, Hing L; Trevillyan, James M

2006-06-15

A series of (5-substituted pyrrolidinyl-2-carbonyl)-2-cyanopyrrolidine (C5-Pro-Pro) analogues was discovered as dipeptidyl peptidase IV (DPPIV) inhibitors as a potential treatment of diabetes and obesity. X-ray crystallography data show that these inhibitors bind to the catalytic site of DPPIV with the cyano group forming a covalent bond with the serine residue of DPPIV. The C5-substituents make various interactions with the enzyme and affect potency, chemical stability, selectivity, and PK properties of the inhibitors. Optimized analogues are extremely potent with subnanomolar K(i)'s, are chemically stable, show very little potency decrease in the presence of plasma, and exhibit more than 1,000-fold selectivity against related peptidases. The best compounds also possess good PK and are efficacious in lowering blood glucose in an oral glucose tolerance test in ZDF rats.

Is substance P released from slices of the rat spinal cord inactivated by peptidase(s) distinct from both 'enkephalinase' and 'angiotensin-converting enzyme'?

PubMed

Mauborgne, A; Bourgoin, S; Benoliel, J J; Hamon, M; Cesselin, F

1991-02-25

Studies on the effects of peptidase inhibitors on substance P-like immunoreactive material (SPLI) released by K(+)-induced depolarization from slices of the rat spinal cord showed that bacitracin was the most potent agent to protect SPLI from degradation. Captopril and thiorphan which inhibit, respectively, angiotensin I converting enzyme and endopeptidase-24.11 also protected SPLI from degradation. However other inhibitors of these two enzymes, kelatorphan for endopeptidase-24.11 and enalaprilat for angiotensin I converting enzyme were essentially inactive, indicating that both enzymes are probably not involved in the degradation of endogenous substance P. Instead, the non-additive protecting effect of bacitracin, captopril and thiorphan might be due to the blockade of some 'bacitracin-sensitive enzyme' playing a key role in the catabolism of SP within the rat spinal cord.

Recent progress of the development of dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes mellitus.

PubMed

Li, Ning; Wang, Li-Jun; Jiang, Bo; Li, Xiang-Qian; Guo, Chuan-Long; Guo, Shu-Ju; Shi, Da-Yong

2018-05-10

Diabetes is a fast growing chronic metabolic disorder around the world. Dipeptidyl peptidase-4 (DPP-4) is a new promising target during type 2 diabetes glycemic control. Thus, a number of potent DPP-4 inhibitors were developed and play a rapidly evolving role in the management of type 2 diabetes in recent years. This article reviews the development of synthetic and natural DPP-4 inhibitors from 2012 to 2017 and provides their physico-chemical properties, biological activities against DPP-4 and selectivity over dipeptidyl peptidase-8/9. Moreover, the glucose-lowering mechanisms and the active site of DPP-4 are also discussed. We also discuss strategies and structure-activity relationships for identifying potent DPP-4 inhibitors, which will provide useful information for developing potent DPP-4 drugs as type 2 diabtes treatments. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

NAAG Peptidase Inhibitors Act via mGluR3: Animal Models of Memory, Alzheimer's, and Ethanol Intoxication.

PubMed

Olszewski, Rafal T; Janczura, Karolina J; Bzdega, Tomasz; Der, Elise K; Venzor, Faustino; O'Rourke, Brennen; Hark, Timothy J; Craddock, Kirsten E; Balasubramanian, Shankar; Moussa, Charbel; Neale, Joseph H

2017-09-01

Glutamate carboxypeptidase II (GCPII) inactivates the peptide neurotransmitter N-acetylaspartylglutamate (NAAG) following synaptic release. Inhibitors of GCPII increase extracellular NAAG levels and are efficacious in animal models of clinical disorders via NAAG activation of a group II metabotropic glutamate receptor. mGluR2 and mGluR3 knock-out (ko) mice were used to test the hypothesis that mGluR3 mediates the activity of GCPII inhibitors ZJ43 and 2-PMPA in animal models of memory and memory loss. Short- (1.5 h) and long- (24 h) term novel object recognition tests were used to assess memory. Treatment with ZJ43 or 2-PMPA prior to acquisition trials increased long-term memory in mGluR2, but not mGluR3, ko mice. Nine month-old triple transgenic Alzheimer's disease model mice exhibited impaired short-term novel object recognition memory that was rescued by treatment with a NAAG peptidase inhibitor. NAAG peptidase inhibitors and the group II mGluR agonist, LY354740, reversed the short-term memory deficit induced by acute ethanol administration in wild type mice. 2-PMPA also moderated the effect of ethanol on short-term memory in mGluR2 ko mice but failed to do so in mGluR3 ko mice. LY354740 and ZJ43 blocked ethanol-induced motor activation. Both GCPII inhibitors and LY354740 also significantly moderated the loss of motor coordination induced by 2.1 g/kg ethanol treatment. These data support the conclusion that inhibitors of glutamate carboxypeptidase II are efficacious in object recognition models of normal memory and memory deficits via an mGluR3 mediated process, actions that could have widespread clinical applications.

Inhibition of serine-peptidase activity enhances the generation of a survivin-derived HLA-A2-presented CTL epitope in colon-carcinoma cells.

PubMed

Preta, G; Marescotti, D; Fortini, C; Carcoforo, P; Castelli, C; Masucci, M; Gavioli, R

2008-12-01

Cytotoxic T lymphocytes eliminate tumor cells expressing antigenic peptides in the context of MHC-I molecules. Peptides are generated during protein degradation by the proteasome and resulting products, surviving cytosolic amino-peptidases activity, may be presented by MHC-I molecules. The MHC-I processing pathway is altered in a large number of malignancies and modulation of antigen generation is one strategy employed by cells to evade immune control. In this study we analyzed the generation and presentation of a survivin-derived CTL epitope in HLA-A2-positive colon-carcinoma cells. Although all cell lines expressed the anti-apoptotic protein survivin, some tumors were poorly recognized by ELTLGEFLKL (ELT)-specific CTL cultures. The expression of MHC-I or TAP molecules was similar in all cell lines suggesting that tumors not recognized by CTLs may present defects in the generation of the ELT-epitope which could be due either to lack of generation or to subsequent degradation of the epitope. The cells were analyzed for the expression and the activity of extra-proteasomal peptidases. A significant overexpression and higher activity of TPPII was observed in colon-carcinoma cells which are not killed by ELT-specific CTLs, suggesting a possible role of TPPII in the degradation of the ELT-epitope. To confirm the role of TPPII in the degradation of the ELT-peptide, we showed that treatment of colon-carcinoma cells with a TPPII inhibitor resulted in a dose-dependent increased sensitivity to ELT-specific CTLs. These results suggest that TPPII is involved in degradation of the ELT-peptide, and its overexpression may contribute to the immune escape of colon-carcinoma cells.

HIV Aspartic Peptidase Inhibitors Modulate Surface Molecules and Enzyme Activities Involved with Physiopathological Events in Fonsecaea pedrosoi

PubMed Central

Palmeira, Vanila F.; Alviano, Daniela S.; Braga-Silva, Lys A.; Goulart, Fátima R. V.; Granato, Marcela Q.; Rozental, Sonia; Alviano, Celuta S.; Santos, André L. S.; Kneipp, Lucimar F.

2017-01-01

Fonsecaea pedrosoi is the main etiological agent of chromoblastomycosis, a recalcitrant disease that is extremely difficult to treat. Therefore, new chemotherapeutics to combat this fungal infection are urgently needed. Although aspartic peptidase inhibitors (PIs) currently used in the treatment of human immunodeficiency virus (HIV) have shown anti-F. pedrosoi activity their exact mechanisms of action have not been elucidated. In the present study, we have investigated the effects of four HIV-PIs on crucial virulence attributes expressed by F. pedrosoi conidial cells, including surface molecules and secreted enzymes, both of which are directly involved in the disease development. In all the experiments, conidia were treated with indinavir, nelfinavir, ritonavir and saquinavir (100 μM) for 24 h, and then fungal cells were used to evaluate the effects of HIV-PIs on different virulence attributes expressed by F. pedrosoi. In comparison to untreated controls, exposure of F. pedrosoi cells to HIV-PIs caused (i) reduction on the conidial granularity; (ii) irreversible surface ultrastructural alterations, such as shedding of electron dense and amorphous material from the cell wall, undulations/invaginations of the plasma membrane with and withdrawal of this membrane from the cell wall; (iii) a decrease in both mannose-rich glycoconjugates and melanin molecules and an increase in glucosylceramides on the conidial surface; (iv) inhibition of ergosterol and lanosterol production; (v) reduction in the secretion of aspartic peptidase, esterase and phospholipase; (vi) significant reduction in the viability of non-pigmented conidia compared to pigmented ones. In summary, HIV-PIs are efficient drugs with an ability to block crucial biological processes of F. pedrosoi and can be seriously considered as potential compounds for the development of new chromoblastomycosis chemotherapeutics. PMID:28579986

HIV Aspartic Peptidase Inhibitors Modulate Surface Molecules and Enzyme Activities Involved with Physiopathological Events in Fonsecaea pedrosoi.

PubMed

Palmeira, Vanila F; Alviano, Daniela S; Braga-Silva, Lys A; Goulart, Fátima R V; Granato, Marcela Q; Rozental, Sonia; Alviano, Celuta S; Santos, André L S; Kneipp, Lucimar F

2017-01-01

Fonsecaea pedrosoi is the main etiological agent of chromoblastomycosis, a recalcitrant disease that is extremely difficult to treat. Therefore, new chemotherapeutics to combat this fungal infection are urgently needed. Although aspartic peptidase inhibitors (PIs) currently used in the treatment of human immunodeficiency virus (HIV) have shown anti- F. pedrosoi activity their exact mechanisms of action have not been elucidated. In the present study, we have investigated the effects of four HIV-PIs on crucial virulence attributes expressed by F. pedrosoi conidial cells, including surface molecules and secreted enzymes, both of which are directly involved in the disease development. In all the experiments, conidia were treated with indinavir, nelfinavir, ritonavir and saquinavir (100 μM) for 24 h, and then fungal cells were used to evaluate the effects of HIV-PIs on different virulence attributes expressed by F. pedrosoi . In comparison to untreated controls, exposure of F. pedrosoi cells to HIV-PIs caused (i) reduction on the conidial granularity; (ii) irreversible surface ultrastructural alterations, such as shedding of electron dense and amorphous material from the cell wall, undulations/invaginations of the plasma membrane with and withdrawal of this membrane from the cell wall; (iii) a decrease in both mannose-rich glycoconjugates and melanin molecules and an increase in glucosylceramides on the conidial surface; (iv) inhibition of ergosterol and lanosterol production; (v) reduction in the secretion of aspartic peptidase, esterase and phospholipase; (vi) significant reduction in the viability of non-pigmented conidia compared to pigmented ones. In summary, HIV-PIs are efficient drugs with an ability to block crucial biological processes of F. pedrosoi and can be seriously considered as potential compounds for the development of new chromoblastomycosis chemotherapeutics.

Algorithmic commonalities in the parallel environment

NASA Technical Reports Server (NTRS)

Mcanulty, Michael A.; Wainer, Michael S.

1987-01-01

The ultimate aim of this project was to analyze procedures from substantially different application areas to discover what is either common or peculiar in the process of conversion to the Massively Parallel Processor (MPP). Three areas were identified: molecular dynamic simulation, production systems (rule systems), and various graphics and vision algorithms. To date, only selected graphics procedures have been investigated. They are the most readily available, and produce the most visible results. These include simple polygon patch rendering, raycasting against a constructive solid geometric model, and stochastic or fractal based textured surface algorithms. Only the simplest of conversion strategies, mapping a major loop to the array, has been investigated so far. It is not entirely satisfactory.

A model to assess lactic acid bacteria aminopeptidase activities in Parmigiano Reggiano cheese during ripening.

PubMed

Gatti, M; De Dea Lindner, J; Gardini, F; Mucchetti, G; Bevacqua, D; Fornasari, M E; Neviani, E

2008-11-01

The aim of this work was to investigate in which phases of ripening of Parmigiano Reggiano cheese lactic acid bacteria aminopeptidases present in cheese extract could be involved in release of free amino acids and to better understand the behavior of these enzymes in physical-chemical conditions that are far from their optimum. In particular, we evaluated 6 different substrates to reproduce broad-specificity aminopeptidase N, broad-specificity aminopeptidase C, glutamyl aminopeptidase A, peptidase with high specificity for leucine and alanine, proline iminopeptidase, and X-prolyl dipeptidyl aminopeptidase activities releasing different N-terminal amino acids. The effects of pH, NaCl concentration, and temperature on the enzyme activities of amino acid beta-naphthylamide (betaNA)-substrates were determined by modulating the variables in 19 different runs of an experimental design, which allowed the building of mathematical models able to assess the effect on aminopeptidases activities over a range of values, obtained with bibliographic data, covering different environmental conditions in different zones of the cheese wheel at different aging times. The aminopeptidases tested in this work were present in cell-free Parmigiano Reggiano cheese extract after a 17-mo ripening and were active when tested in model system. The modeling approach shows that to highlight the individual and interactive effects of chemical-physical variables on enzyme activities, it is helpful to determine the true potential of an amino-peptidase in cheese. Our results evidenced that the 6 different lactic acid bacteria peptidases participate in cheese proteolysis and are induced or inhibited by the cheese production parameters that, in turn, depend on the cheese dimension. Generally, temperature and pH exerted the more relevant effects on the enzymatic activities, and in many cases, a relevant interactive effect of these variables was observed. Increasing salt concentration slowed down broad-specificity amino-peptidase C, glutamyl aminopeptidase A, proline iminopeptidase, and peptidase with high specificity for leucine and alanine. Interestingly, this variable did not affect broad-specificity aminopeptidase N and positively affected X-prolyl dipeptidyl aminopeptidase. The models elaborated varying pH, temperatures, and salt concentration and were a useful, low cost, and fast tool to understand the role of the main peptidases in the different phases of cheese ripening in relation to the major environmental factors influencing enzyme activity.

Peptidases of the peripheral chemoreceptors: biochemical, immunological, in vitro hydrolytic studies and electron microscopic analysis of neutral endopeptidase-like activity of the carotid body.

PubMed

Kumar, G K

1997-02-14

The purposes of the present study are to identify and characterize the major peptidase(s) that may be involved in the inactivation of neuropeptides in the mammalian carotid body. Measurements of a number of peptidase activities in the cell-free extract of the cat carotid body using specific substrates and inhibitors indicated that the previously identified neutral endopeptidase (NEP)-like activity [Kumar et al., Brain Res., 517 (1990) 341-343] is the major peptidase in the chemoreceptor tissue. The NEP-like activity of the carotid body was further characterized using a monoclonal antibody to human neutral endopeptidase, EC 3.4.24.11. Immune blot analysis indicated strong immunoreactivity toward the cat and calf carotid bodies but a weak cross-reactivity with the rabbit carotid body. Furthermore, western blot analysis of the cat carotid body extract revealed the presence of a major 97-kDa protein and a minor 200-kDa protein. The 97-kDa NEP form of the carotid body was comparable to EC 3.4.24.11 and was consistent with its reported molecular weight suggesting NEP-like activity of the carotid body is structurally similar to the neutral endopeptidase, EC 3.4.24.11. In order to assess whether NEP is the primary peptide degrading activity in the cat carotid body in vitro hydrolysis studies using substance P (SP) as a model peptide were performed. HPLC analysis showed that SP is hydrolyzed maximally at pH 7.0 by carotid body peptidases with the formation of SP(1-7) and SP(1-8) as stable intermediates. Inhibitors specific to NEP also inhibited the SP-hydrolyzing activity of the carotid body. Analyses of the cell-free extracts showed the occurrence of both NEP and SP-hydrolyzing activities in the rabbit and rat carotid bodies although at 2- and 4-fold lower levels respectively than that observed in the cat carotid body. Immunoelectron microscopy showed that NEP-specific immunoreactivity is associated with the intercellular region between the type I cells and cell clusters of the carotid body. Taken together, the results from this investigation demonstrate that neutral endopeptidase (EC 3.4.24.11) is one of the major endopeptidases which mediates the degradation and inactivation of neuropeptides in the carotid body.

Transgenic sugarcane overexpressing CaneCPI-1 negatively affects the growth and development of the sugarcane weevil Sphenophorus levis.

PubMed

Schneider, Vanessa Karine; Soares-Costa, Andrea; Chakravarthi, Mohan; Ribeiro, Carolina; Chabregas, Sabrina Moutinho; Falco, Maria Cristina; Henrique-Silva, Flavio

2017-01-01

Transgenic sugarcane expressing CaneCPI-1 exhibits resistance to Sphenophorus levis larvae. Transgenic plants have widely been used to improve resistance against insect attack. Sugarcane is an economically important crop; however, great losses are caused by insect attack. Sphenophorus levis is a sugarcane weevil that digs tunnels in the stem base, leading to the destruction of the crop. This insect is controlled inefficiently by chemical insecticides. Transgenic plants expressing peptidase inhibitors represent an important strategy for impairing insect growth and development. Knowledge of the major peptidase group present in the insect gut is critical when choosing the most effective inhibitor. S. levis larvae use cysteine peptidases as their major digestive enzymes, primarily cathepsin L-like activity. In this study, we developed transgenic sugarcane plants that overexpress sugarcane cysteine peptidase inhibitor 1 (CaneCPI-1) and assessed their potential through feeding bioassays with S. levis larvae. Cystatin overexpression in the transgenic plants was evaluated using semi-quantitative RT-PCR, RT-qPCR, and immunoblot assays. A 50% reduction of the average weight was observed in larvae that fed on transgenic plants in comparison to larvae that fed on non-transgenic plants. In addition, transgenic sugarcane exhibited less damage caused by larval attack than the controls. Our results suggest that the overexpression of CaneCPI-1 in sugarcane is a promising strategy for improving resistance against this insect.