The Legionella IcmSW Complex Directly Interacts with DotL to Mediate Translocation of Adaptor-Dependent Substrates

PubMed Central

Sutherland, Molly C.; Nguyen, Thuy Linh; Tseng, Victor; Vogel, Joseph P.

2012-01-01

Legionella pneumophila is a Gram-negative bacterium that replicates within human alveolar macrophages by evasion of the host endocytic pathway through the formation of a replicative vacuole. Generation of this vacuole is dependent upon the secretion of over 275 effector proteins into the host cell via the Dot/Icm type IVB secretion system (T4SS). The type IV coupling protein (T4CP) subcomplex, consisting of DotL, DotM, DotN, IcmS and IcmW, was recently defined. DotL is proposed to be the T4CP of the L. pneumophila T4SS based on its homology to known T4CPs, which function as inner-membrane receptors for substrates. As a result, DotL is hypothesized to play an integral role(s) in the L. pneumophila T4SS for the engagement and translocation of substrates. To elucidate this role, a genetic approach was taken to screen for dotL mutants that were unable to survive inside host cells. One mutant, dotLY725Stop, did not interact with the type IV adaptor proteins IcmS/IcmW (IcmSW) leading to the identification of an IcmSW-binding domain on DotL. Interestingly, the dotLY725Stop mutant was competent for export of one class of secreted effectors, the IcmSW-independent substrates, but exhibited a specific defect in secretion of IcmSW-dependent substrates. This differential secretion illustrates that DotL requires a direct interaction with the type IV adaptor proteins for the secretion of a major class of substrates. Thus, by identifying a new target for IcmSW, we have discovered that the type IV adaptors perform an additional role in the export of substrates by the L. pneumophila Dot/Icm T4SS. PMID:23028312

Translocation of Helicobacter pylori CagA into Gastric Epithelial Cells by Type IV Secretion

NASA Astrophysics Data System (ADS)

Odenbreit, Stefan; Püls, Jürgen; Sedlmaier, Bettina; Gerland, Elke; Fischer, Wolfgang; Haas, Rainer

2000-02-01

The Gram-negative bacterium Helicobacter pylori is a causative agent of gastritis and peptic ulcer disease in humans. Strains producing the CagA antigen (cagA+) induce strong gastric inflammation and are strongly associated with gastric adenocarcinoma and MALT lymphoma. We show here that such strains translocate the bacterial protein CagA into gastric epithelial cells by a type IV secretion system, encoded by the cag pathogenicity island. CagA is tyrosine-phosphorylated and induces changes in the tyrosine phosphorylation state of distinct cellular proteins. Modulation of host cells by bacterial protein translocation adds a new dimension to the chronic Helicobacter infection with yet unknown consequences.

Histoplasma capsulatum encodes a dipeptidyl peptidase active against the mammalian immunoregulatory peptide, substance P.

PubMed

Cooper, Kendal G; Zarnowski, Robert; Woods, Jon P

2009-01-01

The pathogenic fungus Histoplasma capsulatum secretes dipeptidyl peptidase (Dpp) IV enzyme activity and has two putative DPPIV homologs (HcDPPIVA and HcDPPIVB). We previously showed that HcDPPIVB is the gene responsible for the majority of secreted DppIV activity in H. capsulatum culture supernatant, while we could not detect any functional contribution from HcDPPIVA. In order to determine whether HcDPPIVA encodes a functional DppIV enzyme, we expressed HcDPPIVA in Pichia pastoris and purified the recombinant protein. The recombinant enzyme cleaved synthetic DppIV substrates and had similar biochemical properties to other described DppIV enzymes, with temperature and pH optima of 42 degrees C and 8, respectively. Recombinant HcDppIVA cleaved the host immunoregulatory peptide substance P, indicating the enzyme has the potential to affect the immune response during infection. Expression of HcDPPIVA under heterologous regulatory sequences in H. capsulatum resulted in increased secreted DppIV activity, indicating that the encoded protein can be expressed and secreted by its native organism. However, HcDPPIVA was not required for virulence in a murine model of histoplasmosis. This work reports a fungal enzyme that can function to cleave the immunomodulatory host peptide substance P.

AtlasT4SS: a curated database for type IV secretion systems.

PubMed

Souza, Rangel C; del Rosario Quispe Saji, Guadalupe; Costa, Maiana O C; Netto, Diogo S; Lima, Nicholas C B; Klein, Cecília C; Vasconcelos, Ana Tereza R; Nicolás, Marisa F

2012-08-09

The type IV secretion system (T4SS) can be classified as a large family of macromolecule transporter systems, divided into three recognized sub-families, according to the well-known functions. The major sub-family is the conjugation system, which allows transfer of genetic material, such as a nucleoprotein, via cell contact among bacteria. Also, the conjugation system can transfer genetic material from bacteria to eukaryotic cells; such is the case with the T-DNA transfer of Agrobacterium tumefaciens to host plant cells. The system of effector protein transport constitutes the second sub-family, and the third one corresponds to the DNA uptake/release system. Genome analyses have revealed numerous T4SS in Bacteria and Archaea. The purpose of this work was to organize, classify, and integrate the T4SS data into a single database, called AtlasT4SS - the first public database devoted exclusively to this prokaryotic secretion system. The AtlasT4SS is a manual curated database that describes a large number of proteins related to the type IV secretion system reported so far in Gram-negative and Gram-positive bacteria, as well as in Archaea. The database was created using the RDBMS MySQL and the Catalyst Framework based in the Perl programming language and using the Model-View-Controller (MVC) design pattern for Web. The current version holds a comprehensive collection of 1,617 T4SS proteins from 58 Bacteria (49 Gram-negative and 9 Gram-Positive), one Archaea and 11 plasmids. By applying the bi-directional best hit (BBH) relationship in pairwise genome comparison, it was possible to obtain a core set of 134 clusters of orthologous genes encoding T4SS proteins. In our database we present one way of classifying orthologous groups of T4SSs in a hierarchical classification scheme with three levels. The first level comprises four classes that are based on the organization of genetic determinants, shared homologies, and evolutionary relationships: (i) F-T4SS, (ii) P-T4SS, (iii) I-T4SS, and (iv) GI-T4SS. The second level designates a specific well-known protein families otherwise an uncharacterized protein family. Finally, in the third level, each protein of an ortholog cluster is classified according to its involvement in a specific cellular process. AtlasT4SS database is open access and is available at http://www.t4ss.lncc.br.

Delivery of two-step transcription amplification exendin-4 plasmid system with arginine-grafted bioreducible polymer in type 2 diabetes animal model

PubMed Central

Kim, Pyung-Hwan; Lee, Minhyung; Kim, Sung Wan

2012-01-01

Exendin-4, glucagon-like peptide 1 (GLP-1) receptor agonist, is an exocrine hormone, which has potent insulinotropic actions similar to GLP-1 such as stimulating insulin biosynthesis, facilitating glucose-concentration dependent insulin secretion, slowing gastric emptying, reducing food intake and stimulating β-cell proliferation. Exendin-4, also, has a longer half-life than GLP-1, due to itsresistance to degradation by dipeptidyl peptidase IV (DPP-IV). In spite of its many advantages as a therapeutic agent for diabetes, its clinical application is still restricted. Thus, to improve the activity of exendin-4 in vivo, gene therapy system was developed as an alternative method. An exendin-4 expression system was constructed using the two-step transcription amplification (TSTA) system, which is composed of pβ-Gal4-p65 and pUAS-SP-exendin-4 with combining the advantages of signal peptide (SP) in order to facilitate its secretion in ectopic cells or tissue. Arginine-grafted cyctaminebisacrylamide-diaminohexane polymer (ABP) was used as a gene carrier. Increased expression of exendin-4, glucose dependent insulin secretion in NIT-1 insulinoma cells, and high insulin expression in the presence of DPP-IV were evaluated in vitro after delivery of ABP/TSTA-SP-exendin-4. Blood glucose levels in diabetic mice were decreased dramatically from the third day for experimental period after single intravenous administration with ABP/TSTA-SP-exendin-4. The highest insulinotropic effect of exendin-4 was also observed in the ABP/TSTA/SP-exendin-4-treated mice groups, compared with the others groups from the 3rd day after injection. TSTA exendin-4 expression system with SP and ABP polymer has a potential gene therapy for the treatment of type 2 diabetes. PMID:22705459

Histoplasma capsulatum Encodes a Dipeptidyl Peptidase Active against the Mammalian Immunoregulatory Peptide, Substance P

PubMed Central

Cooper, Kendal G.; Zarnowski, Robert; Woods, Jon P.

2009-01-01

The pathogenic fungus Histoplasma capsulatum secretes dipeptidyl peptidase (Dpp) IV enzyme activity and has two putative DPPIV homologs (HcDPPIVA and HcDPPIVB). We previously showed that HcDPPIVB is the gene responsible for the majority of secreted DppIV activity in H. capsulatum culture supernatant, while we could not detect any functional contribution from HcDPPIVA. In order to determine whether HcDPPIVA encodes a functional DppIV enzyme, we expressed HcDPPIVA in Pichia pastoris and purified the recombinant protein. The recombinant enzyme cleaved synthetic DppIV substrates and had similar biochemical properties to other described DppIV enzymes, with temperature and pH optima of 42°C and 8, respectively. Recombinant HcDppIVA cleaved the host immunoregulatory peptide substance P, indicating the enzyme has the potential to affect the immune response during infection. Expression of HcDPPIVA under heterologous regulatory sequences in H. capsulatum resulted in increased secreted DppIV activity, indicating that the encoded protein can be expressed and secreted by its native organism. However, HcDPPIVA was not required for virulence in a murine model of histoplasmosis. This work reports a fungal enzyme that can function to cleave the immunomodulatory host peptide substance P. PMID:19384411

Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum

PubMed Central

Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H.; Engel, Eli; Kaunitz, Jonathan D.

2012-01-01

Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal l-glutamate (l-Glu) and 5′-inosine monophosphate (IMP) synergistically increases duodenal HCO3− secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3− secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3− secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. l-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced l-Glu/IMP-induced HCO3− secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3− secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3− secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced l-Glu/IMP-induced HCO3− secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal l-Glu/IMP-induced and TGR5 agonist-induced HCO3− secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3− secretion. PMID:22821947

Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum.

PubMed

Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H; Engel, Eli; Kaunitz, Jonathan D; Akiba, Yasutada

2012-10-01

Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal L-glutamate (L-Glu) and 5'-inosine monophosphate (IMP) synergistically increases duodenal HCO3- secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3- secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3- secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. L-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without luminal perfusion (0.1 mM) or intravenous (iv) injection (3 μmol/kg) of the DPPIV inhibitor NVP728. The loop was also perfused with a selective TGR5 agonist betulinic acid (BTA, 10 μM) or the non-bile acid type TGR5 agonist 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N,5-dimethylisoxazole-4-carboxamide (CCDC; 10 μM). DPPIV activity visualized by use of the fluorogenic substrate was present on the duodenal brush border and submucosal layer, both abolished by the incubation with NVP728 (0.1 mM). An iv injection of NVP728 enhanced L-Glu/IMP-induced HCO3- secretion, whereas luminal perfusion of NVP728 had no effect. BTA or CCDC had little effect on HCO3- secretion, whereas NVP728 iv markedly enhanced BTA- or CCDC-induced HCO3- secretion, the effects inhibited by a GLP-2 receptor antagonist. Coperfusion of the TGR5 agonist enhanced L-Glu/IMP-induced HCO3- secretion with the enhanced GLP-2 release, suggesting that TGR5 activation amplifies nutrient sensing signals. DPPIV inhibition potentiated luminal L-Glu/IMP-induced and TGR5 agonist-induced HCO3- secretion via a GLP-2 pathway, suggesting that the modulation of the local concentration of the endogenous secretagogue GLP-2 by luminal compounds and DPPIV inhibition helps regulate protective duodenal HCO3- secretion.

Protein Secretion Systems in Pseudomonas aeruginosa: An Essay on Diversity, Evolution, and Function

PubMed Central

Filloux, Alain

2011-01-01

Protein secretion systems are molecular nanomachines used by Gram-negative bacteria to thrive within their environment. They are used to release enzymes that hydrolyze complex carbon sources into usable compounds, or to release proteins that capture essential ions such as iron. They are also used to colonize and survive within eukaryotic hosts, causing acute or chronic infections, subverting the host cell response and escaping the immune system. In this article, the opportunistic human pathogen Pseudomonas aeruginosa is used as a model to review the diversity of secretion systems that bacteria have evolved to achieve these goals. This diversity may result from a progressive transformation of cell envelope complexes that initially may not have been dedicated to secretion. The striking similarities between secretion systems and type IV pili, flagella, bacteriophage tail, or efflux pumps is a nice illustration of this evolution. Differences are also needed since various secretion configurations call for diversity. For example, some proteins are released in the extracellular medium while others are directly injected into the cytosol of eukaryotic cells. Some proteins are folded before being released and transit into the periplasm. Other proteins cross the whole cell envelope at once in an unfolded state. However, the secretion system requires conserved basic elements or features. For example, there is a need for an energy source or for an outer membrane channel. The structure of this review is thus quite unconventional. Instead of listing secretion types one after each other, it presents a melting pot of concepts indicating that secretion types are in constant evolution and use basic principles. In other words, emergence of new secretion systems could be predicted the way Mendeleïev had anticipated characteristics of yet unknown elements. PMID:21811488

Regulation of BDNF Release by ARMS/Kidins220 through Modulation of Synaptotagmin-IV Levels.

PubMed

López-Benito, Saray; Sánchez-Sánchez, Julia; Brito, Verónica; Calvo, Laura; Lisa, Silvia; Torres-Valle, María; Palko, Mary E; Vicente-García, Cristina; Fernández-Fernández, Seila; Bolaños, Juan P; Ginés, Silvia; Tessarollo, Lino; Arévalo, Juan C

2018-06-06

BDNF is a growth factor with important roles in the nervous system in both physiological and pathological conditions, but the mechanisms controlling its secretion are not completely understood. Here, we show that ARMS/Kidins220 negatively regulates BDNF secretion in neurons from the CNS and PNS. Downregulation of the ARMS/Kidins220 protein in the adult mouse brain increases regulated BDNF secretion, leading to its accumulation in the striatum. Interestingly, two mouse models of Huntington's disease (HD) showed increased levels of ARMS/Kidins220 in the hippocampus and regulated BDNF secretion deficits. Importantly, reduction of ARMS/Kidins220 in hippocampal slices from HD mice reversed the impaired regulated BDNF release. Moreover, there are increased levels of ARMS/Kidins220 in the hippocampus and PFC of patients with HD. ARMS/Kidins220 regulates Synaptotagmin-IV levels, which has been previously observed to modulate BDNF secretion. These data indicate that ARMS/Kidins220 controls the regulated secretion of BDNF and might play a crucial role in the pathogenesis of HD. SIGNIFICANCE STATEMENT BDNF is an important growth factor that plays a fundamental role in the correct functioning of the CNS. The secretion of BDNF must be properly controlled to exert its functions, but the proteins regulating its release are not completely known. Using neuronal cultures and a new conditional mouse to modulate ARMS/Kidins220 protein, we report that ARMS/Kidins220 negatively regulates BDNF secretion. Moreover, ARMS/Kidins220 is overexpressed in two mouse models of Huntington's disease (HD), causing an impaired regulation of BDNF secretion. Furthermore, ARMS/Kidins220 levels are increased in brain samples from HD patients. Future studies should address whether ARMS/Kidins220 has any function on the pathophysiology of HD. Copyright © 2018 the authors 0270-6474/18/385415-14$15.00/0.

Targeting bacterial secretion systems: benefits of disarmament in the microcosm.

PubMed

Baron, Christian; Coombes, Brian

2007-03-01

Secretion systems are used by many bacterial pathogens for the delivery of virulence factors to the extracellular space or directly into host cells. They are attractive targets for the development of novel anti-virulence drugs as their inactivation would lead to pathogen attenuation or avirulence, followed by clearance of the bacteria by the immune system. This review will present the state of knowledge on the assembly and function of type II, type III and type IV secretion systems in Gram-negative bacteria focusing on insights provided by structural analyses of several key components. The suitability of transcription factors regulating the expression of secretion system components and of ATPases, lytic transglycosylases and protein assembly factors as drug targets will be discussed. Recent progress using innovative in vivo as well as in vitro screening strategies led to a first set of secretion system inhibitors with potential for further development as anti-infectives. The discovery of such inhibitors offers exciting and innovative opportunities to further develop these anti-virulence drugs into monotherapy or in combination with classical antibiotics. Bacterial growth per se would not be inhibited by such drugs so that the selection for mutations causing resistance could be reduced. Secretion system inhibitors may therefore avoid many of the problems associated with classical antibiotics and may constitute a valuable addition to our arsenal for the treatment of bacterial infections.

Effect of Melanotan-II on Brain Fos Immunoreactivity and Oxytocin Neuronal Activity and Secretion in Rats.

PubMed

Paiva, L; Sabatier, N; Leng, G; Ludwig, M

2017-02-01

Melanocortins stimulate the central oxytocin systems that are involved in regulating social behaviours. Alterations in central oxytocin have been linked to neurological disorders such as autism, and melanocortins have been proposed for therapeutic treatment. In the present study, we investigated how systemic administration of melanotan-II (MT-II), a melanocortin agonist, affects oxytocin neuronal activity and secretion in rats. The results obtained show that i.v., but not intranasal, administration of MT-II markedly induced Fos expression in magnocellular neurones of the supraoptic (SON) and paraventricular nuclei (PVN) of the hypothalamus, and this response was attenuated by prior i.c.v. administration of the melanocortin antagonist, SHU-9119. Electrophysiological recordings from identified magnocellular neurones of the SON showed that i.v. administration of MT-II increased the firing rate in oxytocin neurones but did not trigger somatodendritic oxytocin release within the SON as measured by microdialysis. Our data suggest that, after i.v., but not intranasal, administration of MT-II, the activity of magnocellular neurones of the SON is increased. Because previous studies showed that SON oxytocin neurones are inhibited in response to direct application of melanocortin agonists, the actions of i.v. MT-II are likely to be mediated at least partly indirectly, possibly by activation of inputs from the caudal brainstem, where MT-II also increased Fos expression. © 2016 British Society for Neuroendocrinology.

Widespread occurrence of Sinorhizobium meliloti strains with a type IV secretion system

USDA-ARS?s Scientific Manuscript database

Improvement in symbiotic nitrogen fixation would reduce reliance on nitrogen fertilizers but is hampered by poor establishment of introduced strains due to competition by indigenous symbiotic strains. This study investigated the origins, diversity, and competitiveness of Sinorhizobium meliloti (now ...

Comprehensive assessment and performance improvement of effector protein predictors for bacterial secretion systems III, IV and VI.

PubMed

An, Yi; Wang, Jiawei; Li, Chen; Leier, André; Marquez-Lago, Tatiana; Wilksch, Jonathan; Zhang, Yang; Webb, Geoffrey I; Song, Jiangning; Lithgow, Trevor

2018-01-01

Bacterial effector proteins secreted by various protein secretion systems play crucial roles in host-pathogen interactions. In this context, computational tools capable of accurately predicting effector proteins of the various types of bacterial secretion systems are highly desirable. Existing computational approaches use different machine learning (ML) techniques and heterogeneous features derived from protein sequences and/or structural information. These predictors differ not only in terms of the used ML methods but also with respect to the used curated data sets, the features selection and their prediction performance. Here, we provide a comprehensive survey and benchmarking of currently available tools for the prediction of effector proteins of bacterial types III, IV and VI secretion systems (T3SS, T4SS and T6SS, respectively). We review core algorithms, feature selection techniques, tool availability and applicability and evaluate the prediction performance based on carefully curated independent test data sets. In an effort to improve predictive performance, we constructed three ensemble models based on ML algorithms by integrating the output of all individual predictors reviewed. Our benchmarks demonstrate that these ensemble models outperform all the reviewed tools for the prediction of effector proteins of T3SS and T4SS. The webserver of the proposed ensemble methods for T3SS and T4SS effector protein prediction is freely available at http://tbooster.erc.monash.edu/index.jsp. We anticipate that this survey will serve as a useful guide for interested users and that the new ensemble predictors will stimulate research into host-pathogen relationships and inspiration for the development of new bioinformatics tools for predicting effector proteins of T3SS, T4SS and T6SS. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A Gene Transfer Agent and a Dynamic Repertoire of Secretion Systems Hold the Keys to the Explosive Radiation of the Emerging Pathogen Bartonella

PubMed Central

Guy, Lionel; Nystedt, Björn; Toft, Christina; Zaremba-Niedzwiedzka, Katarzyna; Berglund, Eva C.; Granberg, Fredrik; Näslund, Kristina; Eriksson, Ann-Sofie; Andersson, Siv G. E.

2013-01-01

Gene transfer agents (GTAs) randomly transfer short fragments of a bacterial genome. A novel putative GTA was recently discovered in the mouse-infecting bacterium Bartonella grahamii. Although GTAs are widespread in phylogenetically diverse bacteria, their role in evolution is largely unknown. Here, we present a comparative analysis of 16 Bartonella genomes ranging from 1.4 to 2.6 Mb in size, including six novel genomes from Bartonella isolated from a cow, two moose, two dogs, and a kangaroo. A phylogenetic tree inferred from 428 orthologous core genes indicates that the deadly human pathogen B. bacilliformis is related to the ruminant-adapted clade, rather than being the earliest diverging species in the genus as previously thought. A gene flux analysis identified 12 genes for a GTA and a phage-derived origin of replication as the most conserved innovations. These are located in a region of a few hundred kb that also contains 8 insertions of gene clusters for type III, IV, and V secretion systems, and genes for putatively secreted molecules such as cholera-like toxins. The phylogenies indicate a recent transfer of seven genes in the virB gene cluster for a type IV secretion system from a cat-adapted B. henselae to a dog-adapted B. vinsonii strain. We show that the B. henselae GTA is functional and can transfer genes in vitro. We suggest that the maintenance of the GTA is driven by selection to increase the likelihood of horizontal gene transfer and argue that this process is beneficial at the population level, by facilitating adaptive evolution of the host-adaptation systems and thereby expansion of the host range size. The process counters gene loss and forces all cells to contribute to the production of the GTA and the secreted molecules. The results advance our understanding of the role that GTAs play for the evolution of bacterial genomes. PMID:23555299

A gene transfer agent and a dynamic repertoire of secretion systems hold the keys to the explosive radiation of the emerging pathogen Bartonella.

PubMed

Guy, Lionel; Nystedt, Björn; Toft, Christina; Zaremba-Niedzwiedzka, Katarzyna; Berglund, Eva C; Granberg, Fredrik; Näslund, Kristina; Eriksson, Ann-Sofie; Andersson, Siv G E

2013-03-01

Gene transfer agents (GTAs) randomly transfer short fragments of a bacterial genome. A novel putative GTA was recently discovered in the mouse-infecting bacterium Bartonella grahamii. Although GTAs are widespread in phylogenetically diverse bacteria, their role in evolution is largely unknown. Here, we present a comparative analysis of 16 Bartonella genomes ranging from 1.4 to 2.6 Mb in size, including six novel genomes from Bartonella isolated from a cow, two moose, two dogs, and a kangaroo. A phylogenetic tree inferred from 428 orthologous core genes indicates that the deadly human pathogen B. bacilliformis is related to the ruminant-adapted clade, rather than being the earliest diverging species in the genus as previously thought. A gene flux analysis identified 12 genes for a GTA and a phage-derived origin of replication as the most conserved innovations. These are located in a region of a few hundred kb that also contains 8 insertions of gene clusters for type III, IV, and V secretion systems, and genes for putatively secreted molecules such as cholera-like toxins. The phylogenies indicate a recent transfer of seven genes in the virB gene cluster for a type IV secretion system from a cat-adapted B. henselae to a dog-adapted B. vinsonii strain. We show that the B. henselae GTA is functional and can transfer genes in vitro. We suggest that the maintenance of the GTA is driven by selection to increase the likelihood of horizontal gene transfer and argue that this process is beneficial at the population level, by facilitating adaptive evolution of the host-adaptation systems and thereby expansion of the host range size. The process counters gene loss and forces all cells to contribute to the production of the GTA and the secreted molecules. The results advance our understanding of the role that GTAs play for the evolution of bacterial genomes.

Discovery of the type VII ESX-1 secretion needle?

PubMed

Ates, Louis S; Brosch, Roland

2017-01-01

Mycobacterium tuberculosis, the etiological agent of human tuberculosis, harbours five ESAT-6/type VII secretion (ESX/T7S) systems. The first esx gene clusters were identified during the genome-sequencing project of M. tuberculosis H37Rv. Follow-up studies revealed additional genes playing important roles in ESX/T7S systems. Among the latter genes, one can find those that encode Pro-Glu (PE) and Pro-Pro-Glu (PPE) proteins as well as a gene cluster that is encoded >260 kb upstream of the esx-1 locus and encodes ESX-1 secretion-associated proteins EspA (Rv3616c), EspC (Rv3615c) and EspD (Rv3614c). The espACD cluster has been suggested to have an important function in ESX-1 secretion since EspA-EspC and EsxA-EsxB are mutually co-dependent on each other for secretion. However, the molecular mechanism of this co-dependence and interaction between the substrates remained unknown. In this issue of Molecular Microbiology, Lou and colleagues show that EspC forms high-molecular weight polymerization complexes that resemble selected components of type II, III and/or IV secretion systems of Gram-negative bacteria. Indeed, EspC-multimeric complexes form filamentous structures that could well represent a secretion needle of ESX-1 type VII secretion systems. This exciting observation opens new avenues for research to discover and characterize ESX/T7S components and elucidates the co-dependence of EsxA/B secretion with EspA/C. © 2016 John Wiley & Sons Ltd.

The BID Domain of Type IV Secretion Substrates Forms a Conserved Four-Helix Bundle Topped with a Hook.

PubMed

Stanger, Frédéric V; de Beer, Tjaart A P; Dranow, David M; Schirmer, Tilman; Phan, Isabelle; Dehio, Christoph

2017-01-03

The BID (Bep intracellular delivery) domain functions as secretion signal in a subfamily of protein substrates of bacterial type IV secretion (T4S) systems. It mediates transfer of (1) relaxases and the attached DNA during bacterial conjugation, and (2) numerous Bartonella effector proteins (Beps) during protein transfer into host cells infected by pathogenic Bartonella species. Furthermore, BID domains of Beps have often evolved secondary effector functions within host cells. Here, we provide crystal structures for three representative BID domains and describe a novel conserved fold characterized by a compact, antiparallel four-helix bundle topped with a hook. The conserved hydrophobic core provides a rigid scaffold to a surface that, despite a few conserved exposed residues and similarities in charge distribution, displays significant variability. We propose that the genuine function of BID domains as T4S signal may primarily depend on their rigid structure, while the plasticity of their surface may facilitate adaptation to secondary effector functions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Type 4 pili are dispensable for biofilm development in the cyanobacterium Synechococcus elongatus.

PubMed

Nagar, Elad; Zilberman, Shaul; Sendersky, Eleonora; Simkovsky, Ryan; Shimoni, Eyal; Gershtein, Diana; Herzberg, Moshe; Golden, Susan S; Schwarz, Rakefet

2017-07-01

The hair-like cell appendages denoted as type IV pili are crucial for biofilm formation in diverse eubacteria. The protein complex responsible for type IV pilus assembly is homologous with the type II protein secretion complex. In the cyanobacterium Synechococcus elongatus PCC 7942, the gene Synpcc7942_2071 encodes an ATPase homologue of type II/type IV systems. Here, we report that inactivation of Synpcc7942_2071 strongly affected the suite of proteins present in the extracellular milieu (exo-proteome) and eliminated pili observable by electron microscopy. These results support a role for this gene product in protein secretion as well as in pili formation. As we previously reported, inactivation of Synpcc7942_2071 enables biofilm formation and suppresses the planktonic growth of S. elongatus. Thus, pili are dispensable for biofilm development in this cyanobacterium, in contrast to their biofilm-promoting function in type IV pili-producing heterotrophic bacteria. Nevertheless, pili removal is not required for biofilm formation as evident by a piliated mutant of S. elongatus that develops biofilms. We show that adhesion and timing of biofilm development differ between the piliated and non-piliated strains. The study demonstrates key differences in the process of biofilm formation between cyanobacteria and well-studied type IV pili-producing heterotrophic bacteria. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

29 CFR 452.97 - Secret ballot.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 2 2014-07-01 2014-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in appropriate...

29 CFR 452.97 - Secret ballot.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 2 2011-07-01 2011-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in appropriate...

29 CFR 452.97 - Secret ballot.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 2 2010-07-01 2010-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in appropriate...

29 CFR 452.97 - Secret ballot.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 2 2012-07-01 2012-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in appropriate...

29 CFR 452.97 - Secret ballot.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 2 2013-07-01 2013-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in appropriate...

Cot kinase plays a critical role in Helicobacter pylori-induced IL-8 expression.

PubMed

Jang, Sungil; Kim, Jinmoon; Cha, Jeong-Heon

2017-04-01

Helicobacter pylori is a major pathogen causing various gastric diseases including gastric cancer. Infection of H. pylori induces pro-inflammatory cytokine IL-8 expression in gastric epithelial cells in the initial inflammatory process. It has been known that H. pylori can modulate Ras-Raf-Mek-Erk signal pathway for IL-8 induction. Recently, it has been shown that another signal molecule, cancer Osaka thyroid oncogene/tumor progression locus 2 (Cot/Tpl2) kinase, activates Mek and Erk and plays a role in the Erk pathway, similar to MAP3K signal molecule Raf kinase. Therefore, the objective of this study was to determine whether Cot kinase might be involved in IL-8 induction caused by H. pylori infection. AGS gastric epithelial cells were infected by H. pylori strain G27 or its isogenic mutants lacking cagA or type IV secretion system followed by treatment with Cot kinase inhibitor (KI) or siRNA specific for Cot kinase. Activation of Erk was assessed by Western blot analysis and expression of IL-8 was measured by ELISA. Treatment with Cot KI reduced both transient and sustained Erk activation. It also reduced early and late IL-8 secretion in the gastric epithelial cell line. Furthermore, siRNA knockdown of Cot inhibited early and late IL-8 secretion induced by H. pylori infection. Taken together, these results suggest that Cot kinase might play a critical role in H. pylori type IV secretion apparatus-dependent early IL-8 secretion and CagA-dependent late IL-8 secretion as an alternative signaling molecule in the Erk pathway.

Type IV Pili in Gram-Positive Bacteria

PubMed Central

Craig, Lisa

2013-01-01

SUMMARY Type IV pili (T4P) are surface-exposed fibers that mediate many functions in bacteria, including locomotion, adherence to host cells, DNA uptake (competence), and protein secretion and that can act as nanowires carrying electric current. T4P are composed of a polymerized protein, pilin, and their assembly apparatuses share protein homologs with type II secretion systems in eubacteria and the flagella of archaea. T4P are found throughout Gram-negative bacterial families and have been studied most extensively in certain model Gram-negative species. Recently, it was discovered that T4P systems are also widespread among Gram-positive species, in particular the clostridia. Since Gram-positive and Gram-negative bacteria have many differences in cell wall architecture and other features, it is remarkable how similar the T4P core proteins are between these organisms, yet there are many key and interesting differences to be found as well. In this review, we compare the two T4P systems and identify and discuss the features they have in common and where they differ to provide a very broad-based view of T4P systems across all eubacterial species. PMID:24006467

Gastric antisecretory role and immunohistochemical localization of cannabinoid receptors in the rat stomach

PubMed Central

Adami, Maristella; Frati, Paolo; Bertini, Simone; Kulkarni-Narla, Anjali; Brown, David R; Caro, Giuseppe de; Coruzzi, Gabriella; Soldani, Giulio

2002-01-01

The role of cannabinoid (CB) receptors in the regulation of gastric acid secretion was investigated in the rat by means of functional experiments and by immunohistochemistry. In anaesthetized rats with lumen-perfused stomach, the non selective CB-receptor agonist WIN 55,212-2 (0.30 – 4.00 μmol kg−1, i.v.) and the selective CB1-receptor agonist HU-210 (0.03 – 1.50 μmol kg−1, i.v.), dose-dependently decreased the acid secretion induced by both pentagastrin (30 nmol kg−1 h−1) and 2-deoxy-D-glucose (1.25 mmol kg−1, i.v.). By contrast, neither WIN 55,212-2 (1 – 4 μmol kg−1, i.v.) nor HU-210 (0.03 – 1.50 μmol kg−1, i.v.) did modify histamine-induced acid secretion (20 μmol kg−1 h−1). The selective CB2-receptor agonist JWH-015 (3 – 10 μmol kg−1, i.v.) was ineffective. The gastric antisecretory effects of WIN 55,212-2 and HU-210 on pentagastrin-induced acid secretion were prevented by the selective CB1-receptor antagonist SR141716A (0.65 μmol kg−1, i.v.) and unaffected by the selective CB2-receptor antagonist SR144528 (0.65 – 2 μmol kg−1, i.v.). Bilateral cervical vagotomy and ganglionic blockade with hexamethonium (10 mg kg−1, i.v., followed by continuous infusion of 10 mg kg−1 h−1) significantly reduced, but not abolished, the maximal inhibitory effect of HU-210 (0.3 μmol kg−1, i.v.) on pentagastrin-induced acid secretion; by contrast, pretreatment with atropine (1 mg kg−1, i.v.) did not modify the antisecretory effect of HU-210. Immunoreactivity to the CB1 receptor was co-localized with that of the cholinergic marker choline acetyltransferase in neural elements innervating smooth muscle, mucosa and submucosal blood vessels of rat stomach fundus, corpus and antrum. In contrast, CB2 receptor-like immunoreactivity was not observed. These results indicate that gastric antisecretory effects of cannabinoids in the rat are mediated by suppression of vagal drive to the stomach through activation of CB1 receptors, located on pre- and postganglionic cholinergic pathways. However, the ineffectiveness of atropine in reducing the effect of HU-210 suggests that the release of non cholinergic excitatory neurotransmitters may be regulated by CB1 receptors. PMID:11934799

Ubiquitin-specific protease 8 deubiquitinates Sec31A and decreases large COPII carriers and collagen IV secretion.

PubMed

Kawaguchi, Kohei; Endo, Akinori; Fukushima, Toshiaki; Madoka, Yuka; Tanaka, Toshiaki; Komada, Masayuki

2018-05-15

Nascent cargo proteins in the endoplasmic reticulum are transported to the Golgi by COPII carriers. Typical COPII vesicles are 60-70 nm in diameter, and much larger macromolecules, such as procollagen, are transported by atypical large COPII carriers in mammalian cells. The formation of large COPII carriers is enhanced by Cul3 ubiquitin ligase, which mono-ubiquitinates Sec31A, a COPII coat protein. However, the deubiquitinating enzyme for Sec31A was unclear. Here, we show that the deubiquitinating enzyme USP8 interacts with and deubiquitinates Sec31A. The interaction was mediated by the adaptor protein STAM1. USP8 overexpression inhibited the formation of large COPII carriers. By contrast, USP8 knockdown caused the accumulation of COPII coat proteins around the cis-Golgi, promoted the intracellular trafficking of procollagen IV from the endoplasmic reticulum to the Golgi, and increased collagen IV secretion. We concluded that USP8 deubiquitinates Sec31A and inhibits the formation of large COPII carriers, thereby suppressing collagen IV secretion. Copyright © 2018 Elsevier Inc. All rights reserved.

Mechanisms underlying metformin-induced secretion of glucagon-like peptide-1 from the intestinal L cell.

PubMed

Mulherin, Andrew J; Oh, Amy H; Kim, Helena; Grieco, Anthony; Lauffer, Lina M; Brubaker, Patricia L

2011-12-01

Glucagon-like peptide-1(7-36NH2) (GLP-1) is secreted by the intestinal L cell in response to both nutrient and neural stimulation, resulting in enhanced glucose-dependent insulin secretion. GLP-1 is therefore an attractive therapeutic for the treatment of type 2 diabetes. The antidiabetic drug, metformin, is known to increase circulating GLP-1 levels, although its mechanism of action is unknown. Direct effects of metformin (5-2000 μm) or another AMP kinase activator, aminoimidazole carboxamide ribonucleotide (100-1000 μm) on GLP-1 secretion were assessed in murine human NCI-H716, and rat FRIC L cells. Neither agent stimulated GLP-1 secretion in any model, despite increasing AMP kinase phosphorylation (P < 0.05-0.01). Treatment of rats with metformin (300 mg/kg, per os) or aminoimidazole carboxamide ribonucleotide (250 mg/kg, sc) increased plasma total GLP-1 over 2 h, reaching 37 ± 9 and 29 ± 9 pg/ml (P < 0.001), respectively, compared with basal (7 ± 1 pg/ml). Plasma activity of the GLP-1-degrading enzyme, dipeptidylpeptidase-IV, was not affected by metformin treatment. Pretreatment with the nonspecific muscarinic antagonist, atropine (1 mg/kg, iv), decreased metformin-induced GLP-1 secretion by 55 ± 11% (P < 0.05). Pretreatment with the muscarinic (M) 3 receptor antagonist, 1-1-dimethyl-4-diphenylacetoxypiperidinium iodide (500 μg/kg, iv), also decreased the GLP-1 area under curve, by 48 ± 8% (P < 0.05), whereas the antagonists pirenzepine (M1) and gallamine (M2) had no effect. Furthermore, chronic bilateral subdiaphragmatic vagotomy decreased basal secretion compared with sham-operated animals (7 ± 1 vs. 13 ± 1 pg/ml, P < 0.001) but did not alter the GLP-1 response to metformin. In contrast, pretreatment with the gastrin-releasing peptide antagonist, RC-3095 (100 μg/kg, sc), reduced the GLP-1 response to metformin, by 55 ± 6% (P < 0.01) at 30 min. These studies elucidate the mechanism underlying metformin-induced GLP-1 secretion and highlight the benefits of using metformin with dipeptidylpeptidase-IV inhibitors in patients with type 2 diabetes.

Ecological fitness and strategies of adaptation of Bartonella species to their hosts and vectors☆

PubMed Central

Chomel, Bruno B.; Boulouis, Henri-Jean; Breitschwerdt, Edward B.; Kasten, Rickie W.; Vayssier-Taussat, Muriel; Birtles, Richard J.; Koehler, Jane E.; Dehio, Christoph

2009-01-01

Bartonella spp. are facultative intracellular bacteria that cause characteristic host-restricted hemotropic infections in mammals and are typically transmitted by blood-sucking arthropods. In the mammalian reservoir, these bacteria initially infect a yet unrecognized primary niche, which seeds organisms into the blood stream leading to the establishment of a long-lasting intra-erythrocytic bacteremia as the hall-mark of infection. Bacterial type IV secretion systems, which are supra-molecular transporters ancestrally related to bacterial conjugation systems, represent crucial pathogenicity factors that have contributed to a radial expansion of the Bartonella lineage in nature by facilitating adaptation to unique mammalian hosts. On the molecular level, the type IV secretion system VirB/VirD4 is known to translocate a cocktail of different effector proteins into host cells, which subvert multiple cellular functions to the benefit of the infecting pathogen. Furthermore, bacterial adhesins mediate a critical, early step in the pathogenesis of the bartonellae by binding to extracellular matrix components of host cells, which leads to firm bacterial adhesion to the cell surface as a prerequisite for the efficient translocation of type IV secretion effector proteins. The best-studied adhesins in bartonellae are the orthologous trimeric autotransporter adhesins, BadA in Bartonella henselae and the Vomp family in Bartonella quintana. Genetic diversity and strain variability also appear to enhance the ability of bartonellae to invade not only specific reservoir hosts, but also accidental hosts, as shown for B. henselae. Bartonellae have been identified in many different blood-sucking arthropods, in which they are typically found to cause extracellular infections of the mid-gut epithelium. Adaptation to specific vectors and reservoirs seems to be a common strategy of bartonellae for transmission and host diversity. However, knowledge regarding arthropod specificity/restriction, the mode of transmission, and the bacterial factors involved in arthropod infection and transmission is still limited. PMID:19284965

The Legionella pneumophila IcmS-LvgA protein complex is important for Dot/Icm-dependent intracellular growth.

PubMed

Vincent, Carr D; Vogel, Joseph P

2006-08-01

Many bacterial pathogens require a functional type IV secretion system (T4SS) for virulence. Legionella pneumophila, the causative agent of Legionnaires' disease, employs the Dot/Icm T4SS to inject a large number of protein substrates into its host, thereby altering phagosome trafficking. The L. pneumophila T4SS substrate SdeA has been shown to require the accessory factor IcmS for its export. IcmS, defined as a type IV adaptor, exists as a heterodimer with IcmW and this complex functions in a manner similar to a type III secretion chaperone. Here we report an interaction between IcmS and the previously identified virulence factor LvgA. Similar to the icmS mutant, the lvgA mutant appears to assemble a fully functional Dot/Icm complex. Both LvgA and IcmS are small, acidic proteins localized to the cytoplasm and are not exported by the Dot/Icm system, suggesting they form a novel type IV adaptor complex. Inactivation of lvgA causes a minimal defect in growth in the human monocytic cell line U937 and the environmental host Acanthamoeba castellanii. However, the lvgA mutant was severely attenuated for intracellular growth of L. pneumophila in mouse macrophages, suggesting LvgA may be a critical factor that confers host specificity.

5 CFR 1312.5 - Authority to classify.

Code of Federal Regulations, 2010 CFR

2010-01-01

... staff and relating to the national security of the United States: (1) Top Secret and below: (i) Deputy... International Affairs. (iv) Associate Director for Natural Resources, Energy and Science. (2) Secret and below...

Effective prediction of bacterial type IV secreted effectors by combined features of both C-termini and N-termini.

PubMed

Wang, Yu; Guo, Yanzhi; Pu, Xuemei; Li, Menglong

2017-11-01

Various bacterial pathogens can deliver their secreted substrates also called as effectors through type IV secretion systems (T4SSs) into host cells and cause diseases. Since T4SS secreted effectors (T4SEs) play important roles in pathogen-host interactions, identifying them is crucial to our understanding of the pathogenic mechanisms of T4SSs. A few computational methods using machine learning algorithms for T4SEs prediction have been developed by using features of C-terminal residues. However, recent studies have shown that targeting information can also be encoded in the N-terminal region of at least some T4SEs. In this study, we present an effective method for T4SEs prediction by novelly integrating both N-terminal and C-terminal sequence information. First, we collected a comprehensive dataset across multiple bacterial species of known T4SEs and non-T4SEs from literatures. Then, three types of distinctive features, namely amino acid composition, composition, transition and distribution and position-specific scoring matrices were calculated for 50 N-terminal and 100 C-terminal residues. After that, we employed information gain represent to rank the importance score of the 150 different position residues for T4SE secretion signaling. At last, 125 distinctive position residues were singled out for the prediction model to classify T4SEs and non-T4SEs. The support vector machine model yields a high receiver operating curve of 0.916 in the fivefold cross-validation and an accuracy of 85.29% for the independent test set.

Effective prediction of bacterial type IV secreted effectors by combined features of both C-termini and N-termini

NASA Astrophysics Data System (ADS)

Wang, Yu; Guo, Yanzhi; Pu, Xuemei; Li, Menglong

2017-11-01

Various bacterial pathogens can deliver their secreted substrates also called as effectors through type IV secretion systems (T4SSs) into host cells and cause diseases. Since T4SS secreted effectors (T4SEs) play important roles in pathogen-host interactions, identifying them is crucial to our understanding of the pathogenic mechanisms of T4SSs. A few computational methods using machine learning algorithms for T4SEs prediction have been developed by using features of C-terminal residues. However, recent studies have shown that targeting information can also be encoded in the N-terminal region of at least some T4SEs. In this study, we present an effective method for T4SEs prediction by novelly integrating both N-terminal and C-terminal sequence information. First, we collected a comprehensive dataset across multiple bacterial species of known T4SEs and non-T4SEs from literatures. Then, three types of distinctive features, namely amino acid composition, composition, transition and distribution and position-specific scoring matrices were calculated for 50 N-terminal and 100 C-terminal residues. After that, we employed information gain represent to rank the importance score of the 150 different position residues for T4SE secretion signaling. At last, 125 distinctive position residues were singled out for the prediction model to classify T4SEs and non-T4SEs. The support vector machine model yields a high receiver operating curve of 0.916 in the fivefold cross-validation and an accuracy of 85.29% for the independent test set.

Demonstration that a Klebsiella pneumoniae subsp. pneumoniae isolated from an insect (Nezara viridula) harbors a functional plasmid-borne type IV secretion system

USDA-ARS?s Scientific Manuscript database

Previously, we reported the isolation of Klebsiella pneumoniae subspecies pneumoniae strain Kp 5-1 from a southern green stink bug (Nezara viridula) that is a significant pest of numerous economically important crops. We subsequently sequenced the strains whole genome. Here, we report the presence...

Central effects of humanin on hepatic triglyceride secretion.

PubMed

Gong, Zhenwei; Su, Kai; Cui, Lingguang; Tas, Emir; Zhang, Ting; Dong, H Henry; Yakar, Shoshana; Muzumdar, Radhika H

2015-08-01

Humanin (HN) is an endogenous mitochondria-associated peptide that has been shown to protect against various Alzheimer's disease-associated insults, myocardial ischemia-reperfusion injury, and reactive oxygen species-induced cell death. We have shown previously that HN improves whole body glucose homeostasis by improving insulin sensitivity and increasing glucose-stimulated insulin secretion (GSIS) from the β-cells. Here, we report that intraperitoneal treatment with one of HN analogs, HNG, decreases body weight gain, visceral fat, and hepatic triglyceride (TG) accumulation in high-fat diet-fed mice. The decrease in hepatic TG accumulation is due to increased activity of hepatic microsomal triglyceride transfer protein (MTTP) and increased hepatic TG secretion. Both intravenous (iv) and intracerebroventricular (icv) infusion of HNG acutely increase TG secretion from the liver. Vagotomy blocks the effect on both iv and icv HNG on TG secretion, suggesting that the effects of HNG on hepatic TG flux are centrally mediated. Our data suggest that HN is a new player in central regulation of peripheral lipid metabolism. Copyright © 2015 the American Physiological Society.

Tachykinin-induced nasal fluid secretion and plasma exudation in the rat: effects of peptidase inhibition.

PubMed

Lindell, E; Svensjö, M E; Malm, L; Petersson, G

1995-05-01

Substance P (SP) evokes fluid secretion and plasma extravasation when applied to the nasal mucosa of rats. SP and another tachykinin, neurokinin A (NKA), are degraded in vitro by neutral endopeptidase (NEP) and angiotensin-1-converting enzyme (ACE). In this study, NKA or SP were applied locally to the nasal mucosa of rats. Subsequent fluid secretion was measured by a filter paper technique. Plasma exudation was derived as the recovery of intravenous (i.v.) administered 125I-albumin from the fluid-containing filter papers. In order to inhibit enzymatic degradation of the tachykinins by NEP and ACE, the rats were treated with i.v. administered phosphoramidon or captopril respectively or their combination. SP evoked fluid secretion that was augmented by phosphoramidon and further enhanced by adding captopril. NKA evoked nasal fluid secretion less effectively than SP and the effect was unaffected by peptidase inhibition. SP, but not NKA, evoked increased plasma exudation but only after pre-treatment with phosphoramidon.

Roles of the Putative Type IV-like Secretion System Key Component VirD4 and PrsA in Pathogenesis of Streptococcus suis Type 2

PubMed Central

Jiang, Xiaowu; Yang, Yunkai; Zhou, Jingjing; Zhu, Lexin; Gu, Yuanxing; Zhang, Xiaoyan; Li, Xiaoliang; Fang, Weihuan

2016-01-01

Streptococcus suis type 2 (SS2) is a zoonotic pathogen causing septic infection, meningitis and pneumonia in pigs and humans. SS2 may cause streptococcal toxic shock syndrome (STSS) probably due to excessive release of inflammatory cytokines. A previous study indicated that the virD4 gene in the putative type IV-like secretion system (T4SS) within the 89K pathogenicity island specific for recent epidemic strains contributed to the development of STSS. However, the functional basis of VirD4 in STSS remains unclear. Here we show that deletion of virD4 led to reduced virulence as shown by about 65% higher LD50, lower bacterial load in liver and brain, and lower level of expression of inflammatory cytokines in mice and cell lines than its parent strain. The ΔVirD4 mutant was more easily phagocytosed, suggesting its role as an anti-phagocytic factor. Oxidative stress that mimic bacterial exposure to respiratory burst of phagocytes upregulated expression of virD4. Proteomic analysis identified 10 secreted proteins of significant differences between the parent and mutant strains under oxidative stress, including PrsA, a peptidyl-prolyl isomerase. The SS2 PrsA expressed in E. coli caused a dose-dependent cell death and increased expression of proinflammatory IL-1β, IL-6 and TNF-α in murine macrophage cells. Our data provide novel insights into the contribution of the VirD4 factor to STSS pathogenesis, possibly via its anti-phagocytic activity, upregulation of its expression upon oxidative stress and its involvement in increased secretion of PrsA as a cell death inducer and proinflammatory effector. PMID:27995095

Effect of mode of administration on guaifenesin pharmacokinetics and expectorant action in the rat model.

PubMed

Kagan, Leonid; Lavy, Eran; Hoffman, Amnon

2009-06-01

Guaifenesin is a very commonly used and prescribed oral expectorant drug. However, its mechanism of action is not completely elucidated and the available information is limited. The purpose was to evaluate whether guaifenesin action on respiratory tract secretion is mediated through a reflex stimulation of the gastric mucosa or by the systemic exposure due to the absorption of the drug to the blood circulation. Guaifenesin was administered to rats by various routes: intravenous bolus, oral gavage, and gastric, jejunal or cecal infusions (through surgically implanted catheters). Phenol red respiratory tract secretion (after intraperitoneal or intravenous injection) was used as a marker for degree of expectorant action. Administration of saline by gavage was used as control. Respiratory secretion following oral bolus was approximately 2-fold higher (p<0.05) than that of control. Following IV administration the increase of respiratory secretion did not occur despite the fact that systemic exposure to guaifenesin was 1.5-fold higher than following oral administration. The abdominal surgery was found to eliminate the effect of guaifenesin although it did not change systemic absorption. Guaifenesin was equally absorbed from all parts of the gastrointestinal tract. It was demonstrated that expectorant action of guaifenesin is mediated by stimulation of the gastrointestinal tract and not by the systemic exposure to the drug.

Functional type 1 secretion system involved in Legionella pneumophila virulence.

PubMed

Fuche, Fabien; Vianney, Anne; Andrea, Claire; Doublet, Patricia; Gilbert, Christophe

2015-02-01

Legionella pneumophila is a Gram-negative pathogen found mainly in water, either in a free-living form or within infected protozoans, where it replicates. This bacterium can also infect humans by inhalation of contaminated aerosols, causing a severe form of pneumonia called legionellosis or Legionnaires' disease. The involvement of type II and IV secretion systems in the virulence of L. pneumophila is now well documented. Despite bioinformatic studies showing that a type I secretion system (T1SS) could be present in this pathogen, the functionality of this system based on the LssB, LssD, and TolC proteins has never been established. Here, we report the demonstration of the functionality of the T1SS, as well as its role in the infectious cycle of L. pneumophila. Using deletion mutants and fusion proteins, we demonstrated that the repeats-in-toxin protein RtxA is secreted through an LssB-LssD-TolC-dependent mechanism. Moreover, fluorescence monitoring and confocal microscopy showed that this T1SS is required for entry into the host cell, although it seems dispensable to the intracellular cycle. Together, these results underline the active participation of L. pneumophila, via its T1SS, in its internalization into host cells. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Functional Type 1 Secretion System Involved in Legionella pneumophila Virulence

PubMed Central

Fuche, Fabien; Vianney, Anne; Andrea, Claire; Doublet, Patricia

2014-01-01

Legionella pneumophila is a Gram-negative pathogen found mainly in water, either in a free-living form or within infected protozoans, where it replicates. This bacterium can also infect humans by inhalation of contaminated aerosols, causing a severe form of pneumonia called legionellosis or Legionnaires' disease. The involvement of type II and IV secretion systems in the virulence of L. pneumophila is now well documented. Despite bioinformatic studies showing that a type I secretion system (T1SS) could be present in this pathogen, the functionality of this system based on the LssB, LssD, and TolC proteins has never been established. Here, we report the demonstration of the functionality of the T1SS, as well as its role in the infectious cycle of L. pneumophila. Using deletion mutants and fusion proteins, we demonstrated that the repeats-in-toxin protein RtxA is secreted through an LssB-LssD-TolC-dependent mechanism. Moreover, fluorescence monitoring and confocal microscopy showed that this T1SS is required for entry into the host cell, although it seems dispensable to the intracellular cycle. Together, these results underline the active participation of L. pneumophila, via its T1SS, in its internalization into host cells. PMID:25422301

Phenolic Compounds from Fermented Berry Beverages Modulated Gene and Protein Expression To Increase Insulin Secretion from Pancreatic β-Cells in Vitro.

PubMed

Johnson, Michelle H; de Mejia, Elvira Gonzalez

2016-03-30

Berries are a rich source of bioactive phenolic compounds that are able to bind and inhibit the enzyme dipeptidyl peptidase-IV (DPP-IV), a current target for type-2 diabetes therapy. The objectives were to determine the role of berry phenolic compounds to modulate incretin-cleaving DPP-IV and its substrate glucagon-like peptide-1 (GLP-1), insulin secretion from pancreatic β-cells, and genes and proteins involved in the insulin secretion pathway using cell culture. Anthocyanins (ANC) from 50% blueberry-50% blackberry (Blu-Bla) and 100% blackberry (Bla) fermented beverages at 50 μM cyanidin-3-glucoside equivalents increased (p < 0.05) glucose-stimulated insulin secretion from pancreatic β-cells (iNS-1E) both when applied directly and following simulated absorption through Caco-2 cells (by 233 and 100 μIU insulin/mL, respectively). ANC 50%Blu-Bla and ANC 100%Bla upregulated the gene for incretin hormone GLP-1 (fold-change 3.0 ± 1.4 and 2.0 ± 0.3, respectively) and genes in the insulin secretory pathway including insulin-like growth factor 1 receptor (iGF1R, 2.3 ± 0.6 and 1.6 ± 0.3, respectively), and increased (p < 0.05) the protein expression of insulin-like growth factor 2 (IGF-II), insulin-like growth factor binding proteins (IGFBP-2 and 3), and vascular endothelial growth factor (VEGF) in iNS-1E cells. Taken together, anthocyanins, predominantly delphinidin-3-arabinoside, from fermented berry beverages have the potential to modulate DPP-IV and its substrate GLP-1, to increase insulin secretion, and to upregulate expression of mRNA of insulin-receptor associated genes and proteins in pancreatic β-cells.

Prokaryotic Information Games: How and When to Take up and Secrete DNA.

PubMed

Stingl, Kerstin; Koraimann, Günther

2017-01-01

Besides transduction via bacteriophages natural transformation and bacterial conjugation are the most important mechanisms driving bacterial evolution and horizontal gene spread. Conjugation systems have evolved in eubacteria and archaea. In Gram-positive and Gram-negative bacteria, cell-to-cell DNA transport is typically facilitated by a type IV secretion system (T4SS). T4SSs also mediate uptake of free DNA in Helicobacter pylori, while most transformable bacteria use a type II secretion/type IV pilus system. In this chapter, we focus on how and when bacteria "decide" that such a DNA transport apparatus is to be expressed and assembled in a cell that becomes competent. Development of DNA uptake competence and DNA transfer competence is driven by a variety of stimuli and often involves intricate regulatory networks leading to dramatic changes in gene expression patterns and bacterial physiology. In both cases, genetically homogeneous populations generate a distinct subpopulation that is competent for DNA uptake or DNA transfer or might uniformly switch into competent state. Phenotypic conversion from one state to the other can rely on bistable genetic networks that are activated stochastically with the integration of external signaling molecules. In addition, we discuss principles of DNA uptake processes in naturally transformable bacteria and intend to understand the exceptional use of a T4SS for DNA import in the gastric pathogen H. pylori. Realizing the events that trigger developmental transformation into competence within a bacterial population will eventually help to create novel and effective therapies against the transmission of antibiotic resistances among pathogens.

Comparative analyses of Legionella species identifies genetic features of strains causing Legionnaires' disease.

PubMed

Gomez-Valero, Laura; Rusniok, Christophe; Rolando, Monica; Neou, Mario; Dervins-Ravault, Delphine; Demirtas, Jasmin; Rouy, Zoe; Moore, Robert J; Chen, Honglei; Petty, Nicola K; Jarraud, Sophie; Etienne, Jerome; Steinert, Michael; Heuner, Klaus; Gribaldo, Simonetta; Médigue, Claudine; Glöckner, Gernot; Hartland, Elizabeth L; Buchrieser, Carmen

2014-01-01

The genus Legionella comprises over 60 species. However, L. pneumophila and L. longbeachae alone cause over 95% of Legionnaires’ disease. To identify the genetic bases underlying the different capacities to cause disease we sequenced and compared the genomes of L. micdadei, L. hackeliae and L. fallonii (LLAP10), which are all rarely isolated from humans. We show that these Legionella species possess different virulence capacities in amoeba and macrophages, correlating with their occurrence in humans. Our comparative analysis of 11 Legionella genomes belonging to five species reveals highly heterogeneous genome content with over 60% representing species-specific genes; these comprise a complete prophage in L. micdadei, the first ever identified in a Legionella genome. Mobile elements are abundant in Legionella genomes; many encode type IV secretion systems for conjugative transfer, pointing to their importance for adaptation of the genus. The Dot/Icm secretion system is conserved, although the core set of substrates is small, as only 24 out of over 300 described Dot/Icm effector genes are present in all Legionella species. We also identified new eukaryotic motifs including thaumatin, synaptobrevin or clathrin/coatomer adaptine like domains. Legionella genomes are highly dynamic due to a large mobilome mainly comprising type IV secretion systems, while a minority of core substrates is shared among the diverse species. Eukaryotic like proteins and motifs remain a hallmark of the genus Legionella. Key factors such as proteins involved in oxygen binding, iron storage, host membrane transport and certain Dot/Icm substrates are specific features of disease-related strains.

Effects of extracellular matrix proteins on macrophage differentiation, growth, and function: comparison of liquid and agar culture systems

NASA Technical Reports Server (NTRS)

Armstrong, J. W.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

1994-01-01

Both spaceflight and skeletal unloading suppress the haematopoietic differentiation of macrophages (Sonnenfeld et al., Aviat. Space Environ. Med., 61:648-653, 1990; Armstrong et al., J. Appl. Physiol., 75:2734-2739, 1993). The mechanism behind this reduction in haematopoiesis has yet to be elucidated. However, changes in bone marrow extracellular matrix (ECM) may be involved. To further understand the role of ECM products in macrophage differentiation, we have performed experiments evaluating the effects of fibronectin, laminin, collagen type I, and collagen type IV on macrophage development and function. Bone marrow-derived macrophages cultured on four different ECM substrates in liquid culture medium showed less growth than those cultured on plastic. Significant morphological differences were seen on each of the substrates used. Phenotypically and functionally, as measured by class II major histocompatibility molecule (MHCII) expression, MAC-2 expression, and the secretion of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), these macrophages were similar. In contrast, bone marrow-derived macrophages cultured in suspension, using agar, showed no difference in growth when exposed to ECM proteins. However, IL-6 and TNF-alpha secretion was affected by fibronectin, laminin, collagen type I, and collagen type IV in a concentration-dependent manner. We conclude that the ECM products fibronectin, laminin, collagen type I, and collagen type IV have profound effects on macrophage development and function. Additionally, we suggest that an ECM-supplemented agar culture system provides an environment more analogous to in vivo bone marrow than does a traditional liquid culture system.

Whole-Genome Sequence of Bradyrhizobium elkanii Strain UASWS1016, a Potential Symbiotic Biofertilizer for Agriculture

PubMed Central

Crovadore, Julien; Calmin, Gautier; Chablais, Romain; Cochard, Bastien; Schulz, Torsten

2016-01-01

Bradyrhizobium elkanii UASWS1016 has been isolated from a wet oxidation sewage plant in Italy. Fully equipped for ammonia assimilation, heavy metal resistances, and aromatic compounds degradation, it carries a large type IV secretion system, specific of plant-associated microbes. Deprived of toxins, it could be considered for agricultural and environmental uses. PMID:27795259

More than a Tad: spatiotemporal control of Caulobacter pili.

PubMed

Mignolet, Johann; Panis, Gaël; Viollier, Patrick H

2018-04-01

The Type IV pilus (T4P) is a powerful and sophisticated bacterial nanomachine involved in numerous cellular processes, including adhesion, DNA uptake and motility. Aside from the well-described subtype T4aP of the Gram-negative genera, including Myxococcus, Pseudomonas and Neisseria, the Tad (tight adherence) pilus secretion system re-shuffles homologous parts from other secretion systems along with uncharacterized components into a new type of protein translocation apparatus. A representative of the Tad apparatus, the Caulobacter crescentus pilus assembly (Cpa) machine is built exclusively at the newborn cell pole once per cell cycle. Recent comprehensive genetic analyses unearthed a myriad of spatiotemporal determinants acting on the Tad/Cpa system, many of which are conserved in other α-proteobacteria, including obligate intracellular pathogens and symbionts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Live cell imaging of phosphoinositide dynamics during Legionella infection.

PubMed

Weber, Stephen; Hilbi, Hubert

2014-01-01

The "accidental" pathogen Legionella pneumophila replicates intracellularly in a distinct compartment, the Legionella-containing vacuole (LCV). To form this specific pathogen vacuole, the bacteria translocate via the Icm/Dot type IV secretion system approximately 300 different effector proteins into the host cell. Several of these secreted effectors anchor to the cytoplasmic face of the LCV membrane by binding to phosphoinositide (PI) lipids. L. pneumophila thus largely controls the localization of secreted bacterial effectors and the recruitment of host factors to the LCV through the modulation of the vacuole membrane PI pattern. The LCV PI pattern and its dynamics can be studied in real-time using fluorescently labeled protein probes stably produced by the soil amoeba Dictyostelium discoideum. In this chapter, we describe a protocol to (1) construct and handle amoeba model systems as a tool for observing PIs in live cell imaging, (2) capture rapid changes in membrane PI patterning during uptake events, and (3) observe the dynamics of LCV PIs over the course of a Legionella infection.

Synthesis of prolyl 4-hydroxylase alpha subunit and type IV collagen in hemocytic granular cells of silkworm, Bombyx mori: Involvement of type IV collagen in self-defense reaction and metamorphosis.

PubMed

Adachi, Takahiro; Tomita, Masahiro; Yoshizato, Katsutoshi

2005-04-01

The present study shows that hemocytic granular cells synthesize and secrete type IV collagen (ColIV) in the silkworm Bombyx mori (B. mori) and suggests that these cells play roles in the formation of basement membrane, the encapsulation of foreign bodies, and the metamorphic remodeling of the gut. The full- and partial-length cDNA of B. mori prolyl 4-hydroxylase alpha subunit (BmP4Halpha) and B. mori ColIV (BmColIV) were cloned, respectively. In situ hybridization and immunocytochemistry on larval tissues and cells identified hemocytic granular cells as the cells that express mRNAs and proteins of both BmP4Halpha and BmColIV. Immunohistochemistry and immunocytochemistry demonstrated that BmColIV was present in the basement membrane and in the secretory granules of granular cells, respectively. Granular cells in culture secreted BmColIV without accompanying the degranulation and discharged it from the granules when the cells were degranulated. Nylon threads were inserted into the hemocoel of larvae. Granular cells concentrated around the nylon threads and encapsulated them as a self-defense reaction. BmColIV was found to be a component of the capsules. Furthermore, the present study showed that actively BmColIV-expressing granular cells accumulated around the midgut epithelium and formed BmColIV-rich thick basal lamina-like structures there in larval to pupal metamorphosis.

Closing Ranks: The Secret of Army Active and Reserve Component Harmony

DTIC Science & Technology

1992-02-11

FUNDING NUMBERS PROGRAM I PROJECT TASK IWORK UNIT ELEMENT NO. NO. NO. [ACCESSION NO 11. TITLE (include Security Classification) Closing Ranks: The Secret of...and recently served on the DOD Total Force Policy Study Group Staff, Washington, DC. iv CLOSING RANKS: THE SECRET OF ARMY ACTIVE AND RESERVE COMPONENT...same old rebuff by the AC senior leadership. If we accept the premise that attitudes and perceptions are the secrets to AC/RC harmony, then the real

The effect of oral and intravenous dextrose on C-peptide secretion in ponies.

PubMed

de Laat, M A; van Haeften, J J; Sillence, M N

2016-02-01

Managing equine hyperinsulinemia is crucial for preventing laminitis, but our understanding of the mechanisms involved in insulin dysregulation in this species is incomplete. C-peptide is co-secreted with insulin but is resistant to hepatic metabolism and can be used to study insulin dysregulation. This study examined C-peptide secretion in serial blood samples collected after oral and i.v. dextrose (0.75 g/kg) administration to 9 ponies (BCS, 7.1 ± 0.5). The ponies were designated as hyperinsulinemic (HI) or normoinsulinemic (NI) responders before the study, using oral glucose tests and fasted glucose-to-insulin ratios, and responses were compared between the 2 groups. C-peptide concentrations increased ( < 0.01) rapidly from fasted levels after both oral and i.v. dextrose, with similar area under the concentration-time curve (AUC) for both tests and a significant correlation with AUC. The AUC was similar in HI and NI ponies after i.v. dextrose, indicating similar pancreatic capacity for both groups. However, for oral dextrose, the AUC and the AUC were markedly higher ( < 0.05) in the HI ponies, indicating a greater secretion rate of these peptides. Slower insulin clearance might have also contributed to the larger AUC in HI ponies, but this hypothesis requires further investigation with specific measures of hepatic insulin clearance.

Regulation of Glucose Homeostasis by GLP-1

PubMed Central

Nadkarni, Prashant; Chepurny, Oleg G.; Holz, George G.

2014-01-01

Glucagon-like peptide-1(7–36)amide (GLP-1) is a secreted peptide that acts as a key determinant of blood glucose homeostasis by virtue of its abilities to slow gastric emptying, to enhance pancreatic insulin secretion, and to suppress pancreatic glucagon secretion. GLP-1 is secreted from L cells of the gastrointestinal mucosa in response to a meal, and the blood glucose-lowering action of GLP-1 is terminated due to its enzymatic degradation by dipeptidyl-peptidase-IV (DPP-IV). Released GLP-1 activates enteric and autonomic reflexes while also circulating as an incretin hormone to control endocrine pancreas function. The GLP-1 receptor (GLP-1R) is a G protein-coupled receptor that is activated directly or indirectly by blood glucose-lowering agents currently in use for the treatment of type 2 diabetes mellitus (T2DM). These therapeutic agents include GLP-1R agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, and langlenatide) and DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin). Investigational agents for use in the treatment of T2DM include GPR119 and GPR40 receptor agonists that stimulate the release of GLP-1 from L cells. Summarized here is the role of GLP-1 to control blood glucose homeo-stasis, with special emphasis on the advantages and limitations of GLP-1-based therapeutics. PMID:24373234

On the role of the gut in diabetic hyperglucagonaemia.

PubMed

Lund, Asger

2017-04-01

Patients with type 2 diabetes are characterised not only by compromised insulin secretion and action, but also by elevated plasma concentrations of the 29-amino acid peptide hormone glucagon, which generally is thought of as a pancreas-derived hormone (produced in and secreted from alpha cells in the islet of Langerhans). In patients with diabetes, circulating glucagon concentrations are elevated in the fasting state and fail to decrease appropriately or even increase in response to ingestion of nutrients. Glucagon is known to be a potent stimulator of hepatic glucose production, and, thus, the elevated glucagon concentrations in diabetes contribute decisively to the predominating trait of patients with diabetes namely hyperglycaemia. Interestingly, studies have shown that while oral intake of glucose results in inappropriately high plasma concentrations of glucagon in patients with diabetes, intravenous (iv) infusion of glucose does not. The mechanisms behind these differential glucagon responses to oral vs. iv glucose administration are currently unexplained. Three hypotheses were tested in the present thesis: 1) Could the inappropriate glucagon response to oral glucose ingestion in patients with diabetes be attributed to the release of glucagonotropic/glucagonostatic peptides secreted from the gut? 2) Could the inappropriate glucagon response to oral glucose ingestion in diabetes be a result of extrapancreatic glucagon secretion (possibly originating from the gut)? And 3) Does the differential glucagon responses between oral and iv glucose administration affect endogenous glucose production (EGP). The overall aim of this PhD thesis was, thus, to investigate the role of the gut in diabetic hyperglucagonaemia and hyperglycaemia. In Study I we examined the effect of the three gut-derived hormones glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) on glucagon secretion in patients with type 2 diabetes. We applied a 50 g-oral glucose tolerance test (OGTT), and five isoglycaemic iv glucose infusions (IIGIs) with either saline, GIP, GLP-1, GLP-2 or a combination of the three hormones. We show that these gut-derived hormones affect glucagon secretion differently and that OGTT-induced secretion of these hormones may play a role in the inappropriate glucagon response to orally ingested glucose in patients with type 2 diabetes with especially GIP acting to increase glucagon secretion. In Study II we examined totally pancreatectomised patients and non-diabetic control subjects during a 75 g-OGTT and an IIGI. We applied sandwich enzyme-linked immunosorbent assay (ELISA) and mass spectrometry-based proteomics for plasma glucagon analysis and show that 29-amino acid glucagon circulates in patients without a pancreas and that glucose stimulation of the gut results in significant hyperglucagonemia in these patients - ultimately confirming the existence of extrapancreatic glucagon secretion in humans. In Study III we examined whether the different responses of insulin and glucagon, respectively, between oral and iv glucose administration translate into differences in EGP and glucose disappearance in patients with type 2 diabetes and non-diabetic control subjects. We applied glucose tracer methodology during a 75 g-OGTT, IIGI and IIGI + iv glucagon (to isolate the effect of glucagon) and show that EGP is less suppressed during OGTT than during IIGI in both patients with type 2 diabetes and non-diabetic control subjects. Articles published in the Danish Medical Journal are “open access”. This means that the articles are distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits any non-commercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Virulence factors encoded by Legionella longbeachae identified on the basis of the genome sequence analysis of clinical isolate D-4968.

PubMed

Kozak, Natalia A; Buss, Meghan; Lucas, Claressa E; Frace, Michael; Govil, Dhwani; Travis, Tatiana; Olsen-Rasmussen, Melissa; Benson, Robert F; Fields, Barry S

2010-02-01

Legionella longbeachae causes most cases of legionellosis in Australia and may be underreported worldwide due to the lack of L. longbeachae-specific diagnostic tests. L. longbeachae displays distinctive differences in intracellular trafficking, caspase 1 activation, and infection in mouse models compared to Legionella pneumophila, yet these two species have indistinguishable clinical presentations in humans. Unlike other legionellae, which inhabit freshwater systems, L. longbeachae is found predominantly in moist soil. In this study, we sequenced and annotated the genome of an L. longbeachae clinical isolate from Oregon, isolate D-4968, and compared it to the previously published genomes of L. pneumophila. The results revealed that the D-4968 genome is larger than the L. pneumophila genome and has a gene order that is different from that of the L. pneumophila genome. Genes encoding structural components of type II, type IV Lvh, and type IV Icm/Dot secretion systems are conserved. In contrast, only 42/140 homologs of genes encoding L. pneumophila Icm/Dot substrates have been found in the D-4968 genome. L. longbeachae encodes numerous proteins with eukaryotic motifs and eukaryote-like proteins unique to this species, including 16 ankyrin repeat-containing proteins and a novel U-box protein. We predict that these proteins are secreted by the L. longbeachae Icm/Dot secretion system. In contrast to the L. pneumophila genome, the L. longbeachae D-4968 genome does not contain flagellar biosynthesis genes, yet it contains a chemotaxis operon. The lack of a flagellum explains the failure of L. longbeachae to activate caspase 1 and trigger pyroptosis in murine macrophages. These unique features of L. longbeachae may reflect adaptation of this species to life in soil.

Whole-Genome Sequence of Bradyrhizobium elkanii Strain UASWS1016, a Potential Symbiotic Biofertilizer for Agriculture.

PubMed

Crovadore, Julien; Calmin, Gautier; Chablais, Romain; Cochard, Bastien; Schulz, Torsten; Lefort, François

2016-10-06

Bradyrhizobium elkanii UASWS1016 has been isolated from a wet oxidation sewage plant in Italy. Fully equipped for ammonia assimilation, heavy metal resistances, and aromatic compounds degradation, it carries a large type IV secretion system, specific of plant-associated microbes. Deprived of toxins, it could be considered for agricultural and environmental uses. Copyright © 2016 Crovadore et al.

A distinct and divergent lineage of genomic island-associated Type IV Secretion Systems in Legionella.

PubMed

Wee, Bryan A; Woolfit, Megan; Beatson, Scott A; Petty, Nicola K

2013-01-01

Legionella encodes multiple classes of Type IV Secretion Systems (T4SSs), including the Dot/Icm protein secretion system that is essential for intracellular multiplication in amoebal and human hosts. Other T4SSs not essential for virulence are thought to facilitate the acquisition of niche-specific adaptation genes including the numerous effector genes that are a hallmark of this genus. Previously, we identified two novel gene clusters in the draft genome of Legionella pneumophila strain 130b that encode homologues of a subtype of T4SS, the genomic island-associated T4SS (GI-T4SS), usually associated with integrative and conjugative elements (ICE). In this study, we performed genomic analyses of 14 homologous GI-T4SS clusters found in eight publicly available Legionella genomes and show that this cluster is unusually well conserved in a region of high plasticity. Phylogenetic analyses show that Legionella GI-T4SSs are substantially divergent from other members of this subtype of T4SS and represent a novel clade of GI-T4SSs only found in this genus. The GI-T4SS was found to be under purifying selection, suggesting it is functional and may play an important role in the evolution and adaptation of Legionella. Like other GI-T4SSs, the Legionella clusters are also associated with ICEs, but lack the typical integration and replication modules of related ICEs. The absence of complete replication and DNA pre-processing modules, together with the presence of Legionella-specific regulatory elements, suggest the Legionella GI-T4SS-associated ICE is unique and may employ novel mechanisms of regulation, maintenance and excision. The Legionella GI-T4SS cluster was found to be associated with several cargo genes, including numerous antibiotic resistance and virulence factors, which may confer a fitness benefit to the organism. The in-silico characterisation of this new T4SS furthers our understanding of the diversity of secretion systems involved in the frequent horizontal gene transfers that allow Legionella to adapt to and exploit diverse environmental niches.

A Distinct and Divergent Lineage of Genomic Island-Associated Type IV Secretion Systems in Legionella

PubMed Central

Wee, Bryan A.; Woolfit, Megan; Beatson, Scott A.; Petty, Nicola K.

2013-01-01

Legionella encodes multiple classes of Type IV Secretion Systems (T4SSs), including the Dot/Icm protein secretion system that is essential for intracellular multiplication in amoebal and human hosts. Other T4SSs not essential for virulence are thought to facilitate the acquisition of niche-specific adaptation genes including the numerous effector genes that are a hallmark of this genus. Previously, we identified two novel gene clusters in the draft genome of Legionella pneumophila strain 130b that encode homologues of a subtype of T4SS, the genomic island-associated T4SS (GI-T4SS), usually associated with integrative and conjugative elements (ICE). In this study, we performed genomic analyses of 14 homologous GI-T4SS clusters found in eight publicly available Legionella genomes and show that this cluster is unusually well conserved in a region of high plasticity. Phylogenetic analyses show that Legionella GI-T4SSs are substantially divergent from other members of this subtype of T4SS and represent a novel clade of GI-T4SSs only found in this genus. The GI-T4SS was found to be under purifying selection, suggesting it is functional and may play an important role in the evolution and adaptation of Legionella. Like other GI-T4SSs, the Legionella clusters are also associated with ICEs, but lack the typical integration and replication modules of related ICEs. The absence of complete replication and DNA pre-processing modules, together with the presence of Legionella-specific regulatory elements, suggest the Legionella GI-T4SS-associated ICE is unique and may employ novel mechanisms of regulation, maintenance and excision. The Legionella GI-T4SS cluster was found to be associated with several cargo genes, including numerous antibiotic resistance and virulence factors, which may confer a fitness benefit to the organism. The in-silico characterisation of this new T4SS furthers our understanding of the diversity of secretion systems involved in the frequent horizontal gene transfers that allow Legionella to adapt to and exploit diverse environmental niches. PMID:24358157

Accurate prediction of bacterial type IV secreted effectors using amino acid composition and PSSM profiles.

PubMed

Zou, Lingyun; Nan, Chonghan; Hu, Fuquan

2013-12-15

Various human pathogens secret effector proteins into hosts cells via the type IV secretion system (T4SS). These proteins play important roles in the interaction between bacteria and hosts. Computational methods for T4SS effector prediction have been developed for screening experimental targets in several isolated bacterial species; however, widely applicable prediction approaches are still unavailable In this work, four types of distinctive features, namely, amino acid composition, dipeptide composition, .position-specific scoring matrix composition and auto covariance transformation of position-specific scoring matrix, were calculated from primary sequences. A classifier, T4EffPred, was developed using the support vector machine with these features and their different combinations for effector prediction. Various theoretical tests were performed in a newly established dataset, and the results were measured with four indexes. We demonstrated that T4EffPred can discriminate IVA and IVB effectors in benchmark datasets with positive rates of 76.7% and 89.7%, respectively. The overall accuracy of 95.9% shows that the present method is accurate for distinguishing the T4SS effector in unidentified sequences. A classifier ensemble was designed to synthesize all single classifiers. Notable performance improvement was observed using this ensemble system in benchmark tests. To demonstrate the model's application, a genome-scale prediction of effectors was performed in Bartonella henselae, an important zoonotic pathogen. A number of putative candidates were distinguished. A web server implementing the prediction method and the source code are both available at http://bioinfo.tmmu.edu.cn/T4EffPred.

Distinct docking and stabilization steps of the Pseudopilus conformational transition path suggest rotational assembly of type IV pilus-like fibers.

PubMed

Nivaskumar, Mangayarkarasi; Bouvier, Guillaume; Campos, Manuel; Nadeau, Nathalie; Yu, Xiong; Egelman, Edward H; Nilges, Michael; Francetic, Olivera

2014-05-06

The closely related bacterial type II secretion (T2S) and type IV pilus (T4P) systems are sophisticated machines that assemble dynamic fibers promoting protein transport, motility, or adhesion. Despite their essential role in virulence, the molecular mechanisms underlying helical fiber assembly remain unknown. Here, we use electron microscopy and flexible modeling to study conformational changes of PulG pili assembled by the Klebsiella oxytoca T2SS. Neural network analysis of 3,900 pilus models suggested a transition path toward low-energy conformations driven by progressive increase in fiber helical twist. Detailed predictions of interprotomer contacts along this path were tested by site-directed mutagenesis, pilus assembly, and protein secretion analyses. We demonstrate that electrostatic interactions between adjacent protomers (P-P+1) in the membrane drive pseudopilin docking, while P-P+3 and P-P+4 contacts determine downstream fiber stabilization steps. These results support a model of a spool-like assembly mechanism for fibers of the T2SS-T4P superfamily. Copyright © 2014 Elsevier Ltd. All rights reserved.

Distinct docking and stabilization steps of the pseudopilus conformational transition path suggest rotational assembly of type IV pilus-like fibers

PubMed Central

Nivaskumar, Mangayarkarasi; Bouvier, Guillaume; Campos, Manuel; Nadeau, Nathalie; Yu, Xiong; Egelman, Edward H.; Nilges, Michael; Francetic, Olivera

2014-01-01

SUMMARY The closely related bacterial type II secretion (T2S) and type IV pilus (T4P) systems are sophisticated machines that assemble dynamic fibers promoting protein transport, motility or adhesion. Despite their essential role in virulence, the molecular mechanisms underlying helical fiber assembly remain unknown. Here we use electron microscopy and flexible modeling to study conformational changes of PulG pili assembled by the Klebsiella oxytoca T2SS. Neural network analysis of 3900 pilus models suggested a transition path towards low-energy conformations driven by progressive increase in fiber helical twist. Detailed predictions of inter-protomer contacts along this path were tested by site-directed mutagenesis, pilus assembly and protein secretion analyses. We demonstrate that electrostatic interactions between adjacent protomers (P-P+1) in the membrane drive pseudopilin docking, while P-P+3 and P-P+4 contacts determine downstream fiber stabilization steps. These results support a new model of a spool-like assembly mechanism for fibers of the T2SS-T4P superfamily. PMID:24685147

Evaluation of insulin secretion and action in New World camelids.

PubMed

Firshman, Anna M; Cebra, Christopher K; Schanbacher, Barbara J; Seaquist, Elizabeth R

2013-01-01

To measure and compare insulin secretion and sensitivity in healthy alpacas and llamas via glucose clamping techniques. 8 llamas and 8 alpacas. Hyperinsulinemic euglycemic clamping (HEC) and hyperglycemic clamping (HGC) were performed on each camelid in a crossover design with a minimum 48-hour washout period between clamping procedures. The HEC technique was performed to measure insulin sensitivity. Insulin was infused IV at 6 mU/min/kg for 4 hours, and an IV infusion of glucose was adjusted to maintain blood glucose concentration at 150 mg/dL. Concentrations of blood glucose and plasma insulin were determined throughout. The HGC technique was performed to assess insulin secretion in response to exogenous glucose infusion. An IV infusion of glucose was administered to maintain blood glucose concentration at 320 mg/dL for 3 hours, and concentrations of blood glucose and plasma insulin were determined throughout. Alpacas and llamas were not significantly different with respect to whole-body insulin sensitivity during HEC or in pancreatic β-cell response during HGC. Alpacas and llamas had markedly lower insulin sensitivity during HEC and markedly lower pancreatic β-cell response during HGC, in comparison with many other species. New World camelids had lower glucose-induced insulin secretion and marked insulin resistance in comparison with other species. This likely contributes to the disorders of fat and glucose metabolism that are common to camelids.

A bacterial toxin-antitoxin module is the origin of inter-bacterial and inter-kingdom effectors of Bartonella.

PubMed

Harms, Alexander; Liesch, Marius; Körner, Jonas; Québatte, Maxime; Engel, Philipp; Dehio, Christoph

2017-10-01

Host-targeting type IV secretion systems (T4SS) evolved from conjugative T4SS machineries that mediate interbacterial plasmid transfer. However, the origins of effectors secreted by these virulence devices have remained largely elusive. Previous work showed that some effectors exhibit homology to toxins of bacterial toxin-antitoxin modules, but the evolutionary trajectories underlying these ties had not been resolved. We previously reported that FicT toxins of FicTA toxin-antitoxin modules disrupt cellular DNA topology via their enzymatic FIC (filamentation induced by cAMP) domain. Intriguingly, the FIC domain of the FicT toxin VbhT of Bartonella schoenbuchensis is fused to a type IV secretion signal-the BID (Bep intracellular delivery) domain-similar to the Bartonella effector proteins (Beps) that are secreted into eukaryotic host cells via the host-targeting VirB T4SS. In this study, we show that the VbhT toxin is an interbacterial effector protein secreted via the conjugative Vbh T4SS that is closely related to the VirB T4SS and encoded by plasmid pVbh of B. schoenbuchensis. We therefore propose that the Vbh T4SS together with its effector VbhT represent an evolutionary missing link on a path that leads from a regular conjugation system and FicTA toxin-antitoxin modules to the VirB T4SS and the Beps. Intriguingly, phylogenetic analyses revealed that the fusion of FIC and BID domains has probably occurred independently in VbhT and the common ancestor of the Beps, suggesting parallel evolutionary paths. Moreover, several other examples of TA module toxins that are bona fide substrates of conjugative T4SS indicate that their recruitment as interbacterial effectors is prevalent and serves yet unknown biological functions in the context of bacterial conjugation. We propose that the adaptation for interbacterial transfer favors the exaptation of FicT and other TA module toxins as inter-kingdom effectors and may thus constitute an important stepping stone in the evolution of host-targeted effector proteins.

A bacterial toxin-antitoxin module is the origin of inter-bacterial and inter-kingdom effectors of Bartonella

PubMed Central

Liesch, Marius

2017-01-01

Host-targeting type IV secretion systems (T4SS) evolved from conjugative T4SS machineries that mediate interbacterial plasmid transfer. However, the origins of effectors secreted by these virulence devices have remained largely elusive. Previous work showed that some effectors exhibit homology to toxins of bacterial toxin-antitoxin modules, but the evolutionary trajectories underlying these ties had not been resolved. We previously reported that FicT toxins of FicTA toxin-antitoxin modules disrupt cellular DNA topology via their enzymatic FIC (filamentation induced by cAMP) domain. Intriguingly, the FIC domain of the FicT toxin VbhT of Bartonella schoenbuchensis is fused to a type IV secretion signal–the BID (Bep intracellular delivery) domain—similar to the Bartonella effector proteins (Beps) that are secreted into eukaryotic host cells via the host-targeting VirB T4SS. In this study, we show that the VbhT toxin is an interbacterial effector protein secreted via the conjugative Vbh T4SS that is closely related to the VirB T4SS and encoded by plasmid pVbh of B. schoenbuchensis. We therefore propose that the Vbh T4SS together with its effector VbhT represent an evolutionary missing link on a path that leads from a regular conjugation system and FicTA toxin-antitoxin modules to the VirB T4SS and the Beps. Intriguingly, phylogenetic analyses revealed that the fusion of FIC and BID domains has probably occurred independently in VbhT and the common ancestor of the Beps, suggesting parallel evolutionary paths. Moreover, several other examples of TA module toxins that are bona fide substrates of conjugative T4SS indicate that their recruitment as interbacterial effectors is prevalent and serves yet unknown biological functions in the context of bacterial conjugation. We propose that the adaptation for interbacterial transfer favors the exaptation of FicT and other TA module toxins as inter-kingdom effectors and may thus constitute an important stepping stone in the evolution of host-targeted effector proteins. PMID:29073136

Astragaloside IV inhibits pathological functions of gastric cancer-associated fibroblasts.

PubMed

Wang, Zhen-Fei; Ma, Da-Guang; Zhu, Zhe; Mu, Yong-Ping; Yang, Yong-Yan; Feng, Li; Yang, Hao; Liang, Jun-Qing; Liu, Yong-Yan; Liu, Li; Lu, Hai-Wen

2017-12-28

To investigate the inhibitory effect of astragaloside IV on the pathological functions of cancer-associated fibroblasts, and to explore the underlying mechanism. Paired gastric normal fibroblast (GNF) and gastric cancer-associated fibroblast (GCAF) cultures were established from resected tissues. GCAFs were treated with vehicle control or different concentrations of astragaloside IV. Conditioned media were prepared from GNFs, GCAFs, control-treated GCAFs, and astragaloside IV-treated GCAFs, and used to culture BGC-823 human gastric cancer cells. Proliferation, migration and invasion capacities of BGC-823 cells were determined by MTT, wound healing, and Transwell invasion assays, respectively. The action mechanism of astragaloside IV was investigated by detecting the expression of microRNAs and the expression and secretion of the oncogenic factor, macrophage colony-stimulating factor (M-CSF), and the tumor suppressive factor, tissue inhibitor of metalloproteinase 2 (TIMP2), in different groups of GCAFs. The expression of the oncogenic pluripotency factors SOX2 and NANOG in BGC-823 cells cultured with different conditioned media was also examined. GCAFs displayed higher capacities to induce BGC-823 cell proliferation, migration, and invasion than GNFs ( P < 0.01). Astragaloside IV treatment strongly inhibited the proliferation-, migration- and invasion-promoting capacities of GCAFs ( P < 0.05 for 10 μmol/L, P < 0.01 for 20 μmol/L and 40 μmol/L). Compared with GNFs, GCAFs expressed a lower level of microRNA-214 ( P < 0.01) and a higher level of microRNA-301a ( P < 0.01). Astragaloside IV treatment significantly up-regulated microRNA-214 expression ( P < 0.01) and down-regulated microRNA-301a expression ( P < 0.01) in GCAFs. Reestablishing the microRNA expression balance subsequently suppressed M-CSF production ( P < 0.01) and secretion ( P < 0.05), and elevated TIMP2 production ( P < 0.01) and secretion ( P < 0.05). Consequently, the ability of GCAFs to increase SOX2 and NANOG expression in BGC-823 cells was abolished by astragaloside IV. Astragaloside IV can inhibit the pathological functions of GCAFs by correcting their dysregulation of microRNA expression, and it is promisingly a potent therapeutic agent regulating tumor microenvironment.

Astragaloside IV inhibits pathological functions of gastric cancer-associated fibroblasts

PubMed Central

Wang, Zhen-Fei; Ma, Da-Guang; Zhu, Zhe; Mu, Yong-Ping; Yang, Yong-Yan; Feng, Li; Yang, Hao; Liang, Jun-Qing; Liu, Yong-Yan; Liu, Li; Lu, Hai-Wen

2017-01-01

AIM To investigate the inhibitory effect of astragaloside IV on the pathological functions of cancer-associated fibroblasts, and to explore the underlying mechanism. METHODS Paired gastric normal fibroblast (GNF) and gastric cancer-associated fibroblast (GCAF) cultures were established from resected tissues. GCAFs were treated with vehicle control or different concentrations of astragaloside IV. Conditioned media were prepared from GNFs, GCAFs, control-treated GCAFs, and astragaloside IV-treated GCAFs, and used to culture BGC-823 human gastric cancer cells. Proliferation, migration and invasion capacities of BGC-823 cells were determined by MTT, wound healing, and Transwell invasion assays, respectively. The action mechanism of astragaloside IV was investigated by detecting the expression of microRNAs and the expression and secretion of the oncogenic factor, macrophage colony-stimulating factor (M-CSF), and the tumor suppressive factor, tissue inhibitor of metalloproteinase 2 (TIMP2), in different groups of GCAFs. The expression of the oncogenic pluripotency factors SOX2 and NANOG in BGC-823 cells cultured with different conditioned media was also examined. RESULTS GCAFs displayed higher capacities to induce BGC-823 cell proliferation, migration, and invasion than GNFs (P < 0.01). Astragaloside IV treatment strongly inhibited the proliferation-, migration- and invasion-promoting capacities of GCAFs (P < 0.05 for 10 μmol/L, P < 0.01 for 20 μmol/L and 40 μmol/L). Compared with GNFs, GCAFs expressed a lower level of microRNA-214 (P < 0.01) and a higher level of microRNA-301a (P < 0.01). Astragaloside IV treatment significantly up-regulated microRNA-214 expression (P < 0.01) and down-regulated microRNA-301a expression (P < 0.01) in GCAFs. Reestablishing the microRNA expression balance subsequently suppressed M-CSF production (P < 0.01) and secretion (P < 0.05), and elevated TIMP2 production (P < 0.01) and secretion (P < 0.05). Consequently, the ability of GCAFs to increase SOX2 and NANOG expression in BGC-823 cells was abolished by astragaloside IV. CONCLUSION Astragaloside IV can inhibit the pathological functions of GCAFs by correcting their dysregulation of microRNA expression, and it is promisingly a potent therapeutic agent regulating tumor microenvironment. PMID:29358859

Protein Kinase LegK2 Is a Type IV Secretion System Effector Involved in Endoplasmic Reticulum Recruitment and Intracellular Replication of Legionella pneumophila ▿

PubMed Central

Hervet, Eva; Charpentier, Xavier; Vianney, Anne; Lazzaroni, Jean-Claude; Gilbert, Christophe; Atlan, Danièle; Doublet, Patricia

2011-01-01

Legionella pneumophila is the etiological agent of Legionnaires' disease. Crucial to the pathogenesis of this intracellular pathogen is its ability to subvert host cell defenses, permitting intracellular replication in specialized vacuoles within host cells. The Dot/Icm type IV secretion system (T4SS), which translocates a large number of bacterial effectors into host cell, is absolutely required for rerouting the Legionella phagosome. Many Legionella effectors display distinctive eukaryotic domains, among which are protein kinase domains. In silico analysis and in vitro phosphorylation assays identified five functional protein kinases, LegK1 to LegK5, encoded by the epidemic L. pneumophila Lens strain. Except for LegK5, the Legionella protein kinases are all T4SS effectors. LegK2 plays a key role in bacterial virulence, as demonstrated by gene inactivation. The legK2 mutant containing vacuoles displays less-efficient recruitment of endoplasmic reticulum markers, which results in delayed intracellular replication. Considering that a kinase-dead substitution mutant of legK2 exhibits the same virulence defects, we highlight here a new molecular mechanism, namely, protein phosphorylation, developed by L. pneumophila to establish a replicative niche and evade host cell defenses. PMID:21321072

Legionella pneumophila Secretes a Mitochondrial Carrier Protein during Infection

PubMed Central

Dolezal, Pavel; Aili, Margareta; Tong, Janette; Jiang, Jhih-Hang; Marobbio, Carlo M.; Lee, Sau fung; Schuelein, Ralf; Belluzzo, Simon; Binova, Eva; Mousnier, Aurelie; Frankel, Gad; Giannuzzi, Giulia; Palmieri, Ferdinando; Gabriel, Kipros; Naderer, Thomas; Hartland, Elizabeth L.; Lithgow, Trevor

2012-01-01

The Mitochondrial Carrier Family (MCF) is a signature group of integral membrane proteins that transport metabolites across the mitochondrial inner membrane in eukaryotes. MCF proteins are characterized by six transmembrane segments that assemble to form a highly-selective channel for metabolite transport. We discovered a novel MCF member, termed Legionella nucleotide carrier Protein (LncP), encoded in the genome of Legionella pneumophila, the causative agent of Legionnaire's disease. LncP was secreted via the bacterial Dot/Icm type IV secretion system into macrophages and assembled in the mitochondrial inner membrane. In a yeast cellular system, LncP induced a dominant-negative phenotype that was rescued by deleting an endogenous ATP carrier. Substrate transport studies on purified LncP reconstituted in liposomes revealed that it catalyzes unidirectional transport and exchange of ATP transport across membranes, thereby supporting a role for LncP as an ATP transporter. A hidden Markov model revealed further MCF proteins in the intracellular pathogens, Legionella longbeachae and Neorickettsia sennetsu, thereby challenging the notion that MCF proteins exist exclusively in eukaryotic organisms. PMID:22241989

Genomic study of the Type IVC secretion system in Clostridium difficile: understanding C. difficile evolution via horizontal gene transfer.

PubMed

Zhang, Wen; Cheng, Ying; Du, Pengcheng; Zhang, Yuanyuan; Jia, Hongbing; Li, Xianping; Wang, Jing; Han, Na; Qiang, Yujun; Chen, Chen; Lu, Jinxing

2017-01-01

Clostridium difficile, the etiological agent of Clostridium difficile infection (CDI), is a gram-positive, spore-forming bacillus that is responsible for ∼20% of antibiotic-related cases of diarrhea and nearly all cases of pseudomembranous colitis. Previous data have shown that a substantial proportion (11%) of the C. difficile genome consists of mobile genetic elements, including seven conjugative transposons. However, the mechanism underlying the formation of a mosaic genome in C. difficile is unknown. The type-IV secretion system (T4SS) is the only secretion system known to transfer DNA segments among bacteria. We searched genome databases to identify a candidate T4SS in C. difficile that could transfer DNA among different C. difficile strains. All T4SS gene clusters in C. difficile are located within genomic islands (GIs), which have variable lengths and structures and are all conjugative transposons. During the horizontal-transfer process of T4SS GIs within the C. difficile population, the excision sites were altered, resulting in different short-tandem repeat sequences among the T4SS GIs, as well as different chromosomal insertion sites and additional regions in the GIs.

Dipeptidyl(amino)peptidase IV and aminopeptidase M metabolize circulating substance P in vivo.

PubMed

Ahmad, S; Wang, L; Ward, P E

1992-03-01

Recent studies have demonstrated that Fischer-344 rats from Japanese Charles River Inc. specifically lack dipeptidyl(amino)peptidase IV (DAP IV-negative; EC 3.4.14.5), whereas Fischer-344 rats from sources within the United States (DAP IV-positive) possess normal DAP IV activity. In the present study, plasma from DAP IV-positive rats metabolized substance P (SP) (5.37 +/- 0.25 nmol/min/ml) via the actions of angiotensin-converting enzyme (EC 3.4.15.1) (1.86 +/- 0.50 nmol/min/ml) and DAP IV (2.56 +/- 0.42 nmol/min/ml). DAP IV sequentially converted SP to SP[3-11] and SP[5-11]. The SP[5-11] metabolite was then rapidly hydrolyzed by plasma aminopeptidase M (AmM; EC 3.4.11.2) (36.2 +/- 4.2 nmol/min/ml). In contrast, SP metabolism by plasma from DAP IV-negative rats was less than half that of control animals (2.14 +/- 0.06 nmol/min/ml), due to a complete lack of DAP IV hydrolysis. The absence of DAP IV was not associated with any differences in angiotensin-converting enzyme-mediated hydrolysis of SP (1.45 +/- 0.11 nmol/min/ml) or AmM-mediated hydrolysis of SP[5-11] (37.1 +/- 0.9 nmol/min/ml). Consistent with this deficiency in SP metabolism, SP was more potent in vivo in stimulating salivary secretion in DAP IV-negative rats compared to DAP IV-positive animals. Potentiation was specific in that SP[5-11], an SP fragment resistant to DAP IV, was equipotent in DAP IV-negative and positive animals. SP[5-11]-induced salivary secretion was potentiated in both strains when AmM-mediated hydrolysis was inhibited by amastatin (20 nmol/min, i.v.). These data provide direct evidence for a significant role for DAP IV and AmM in the in vivo processing of SP and active SP metabolites.

Localization of functional β-xylosidases, encoded by the same single gene, xlsIV (xlnD), from Aspergillus niger E-1.

PubMed

Inoue, Kotomi; Takahashi, Yui; Obara, Ken; Murakami, Shuichiro

2017-03-01

Cell wall-associated β-xylosidase was isolated from Aspergillus niger E-1 and identified as XlsIV, corresponding to the extracellular enzyme XlnD reported previously. xlsIV was transcribed only in the early cultivation period. Cell wall-associated enzyme activity gradually decreased, but extracellular activity increased as the strain grew. These results indicate that XlsIV (XlnD) was secreted into culture after localizing at cell wall.

A bipartite signal mediates the transfer of type IV secretion substrates of Bartonella henselae into human cells.

PubMed

Schulein, Ralf; Guye, Patrick; Rhomberg, Thomas A; Schmid, Michael C; Schröder, Gunnar; Vergunst, Annette C; Carena, Ilaria; Dehio, Christoph

2005-01-18

Bacterial type IV secretion (T4S) systems mediate the transfer of macromolecular substrates into various target cells, e.g., the conjugative transfer of DNA into bacteria or the transfer of virulence proteins into eukaryotic host cells. The T4S apparatus VirB of the vascular tumor-inducing pathogen Bartonella henselae causes subversion of human endothelial cell (HEC) function. Here we report the identification of multiple protein substrates of VirB, which, upon translocation into HEC, mediate all known VirB-dependent cellular changes. These Bartonella-translocated effector proteins (Beps) A-G are encoded together with the VirB system and the T4S coupling protein VirD4 on a Bartonella-specific pathogenicity island. The Beps display a modular architecture, suggesting an evolution by extensive domain duplication and reshuffling. The C terminus of each Bep harbors at least one copy of the Bep-intracellular delivery domain and a short positively charged tail sequence. This biparte C terminus constitutes a transfer signal that is sufficient to mediate VirB/VirD4-dependent intracellular delivery of reporter protein fusions. The Bep-intracellular delivery domain is also present in conjugative relaxases of bacterial conjugation systems. We exemplarily show that the C terminus of such a conjugative relaxase mediates protein transfer through the Bartonella henselae VirB/VirD4 system into HEC. Conjugative relaxases may thus represent the evolutionary origin of the here defined T4S signal for protein transfer into human cells.

Parallel evolution of a type IV secretion system in radiating lineages of the host-restricted bacterial pathogen Bartonella.

PubMed

Engel, Philipp; Salzburger, Walter; Liesch, Marius; Chang, Chao-Chin; Maruyama, Soichi; Lanz, Christa; Calteau, Alexandra; Lajus, Aurélie; Médigue, Claudine; Schuster, Stephan C; Dehio, Christoph

2011-02-10

Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS), and thereby translocated Bartonella effector proteins (Beps), evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial pathogens. Furthermore, our study highlights the remarkable evolvability of T4SSs and their effector proteins, explaining their broad application in bacterial interactions with the environment.

Parallel Evolution of a Type IV Secretion System in Radiating Lineages of the Host-Restricted Bacterial Pathogen Bartonella

PubMed Central

Engel, Philipp; Salzburger, Walter; Liesch, Marius; Chang, Chao-Chin; Maruyama, Soichi; Lanz, Christa; Calteau, Alexandra; Lajus, Aurélie; Médigue, Claudine; Schuster, Stephan C.; Dehio, Christoph

2011-01-01

Adaptive radiation is the rapid origination of multiple species from a single ancestor as the result of concurrent adaptation to disparate environments. This fundamental evolutionary process is considered to be responsible for the genesis of a great portion of the diversity of life. Bacteria have evolved enormous biological diversity by exploiting an exceptional range of environments, yet diversification of bacteria via adaptive radiation has been documented in a few cases only and the underlying molecular mechanisms are largely unknown. Here we show a compelling example of adaptive radiation in pathogenic bacteria and reveal their genetic basis. Our evolutionary genomic analyses of the α-proteobacterial genus Bartonella uncover two parallel adaptive radiations within these host-restricted mammalian pathogens. We identify a horizontally-acquired protein secretion system, which has evolved to target specific bacterial effector proteins into host cells as the evolutionary key innovation triggering these parallel adaptive radiations. We show that the functional versatility and adaptive potential of the VirB type IV secretion system (T4SS), and thereby translocated Bartonella effector proteins (Beps), evolved in parallel in the two lineages prior to their radiations. Independent chromosomal fixation of the virB operon and consecutive rounds of lineage-specific bep gene duplications followed by their functional diversification characterize these parallel evolutionary trajectories. Whereas most Beps maintained their ancestral domain constitution, strikingly, a novel type of effector protein emerged convergently in both lineages. This resulted in similar arrays of host cell-targeted effector proteins in the two lineages of Bartonella as the basis of their independent radiation. The parallel molecular evolution of the VirB/Bep system displays a striking example of a key innovation involved in independent adaptive processes and the emergence of bacterial pathogens. Furthermore, our study highlights the remarkable evolvability of T4SSs and their effector proteins, explaining their broad application in bacterial interactions with the environment. PMID:21347280

What do we know about the secretion and degradation of incretin hormones?

PubMed

Deacon, Carolyn F

2005-06-15

The incretin hormones, glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) are secreted from endocrine cells located in the intestinal mucosa, and act to enhance meal-induced insulin secretion. GIP and GLP-1 concentrations in the plasma rise rapidly after food ingestion, and the presence of unabsorbed nutrients in the intestinal lumen is a strong stimulus for their secretion. Nutrients can stimulate release of both hormones by direct contact with the K-cell (GIP) and L-cell (GLP-1), and this may be the most important signal. However, nutrients also stimulate GLP-1 and GIP secretion indirectly via other mechanisms. Incretin hormone secretion can be modulated neurally, with cholinergic muscarinic, beta-adrenergic and peptidergic (gastrin-releasing peptide, GRP) fibres generally having positive effects, while secretion is restrained by alpha-adrenergic and somatostatinergic fibres. Hormonal factors may also influence incretin hormone secretion. Somatostatin exerts a local inhibitory effect on the activity of both K- and L-cells via a paracrine mechanism, while, in rodents at least, GIP from the proximal intestine has a stimulatory effect on GLP-1 secretion, possibly mediated via a neural loop involving GRP. Once they have been released, both GLP-1 and GIP are subject to rapid degradation. The ubiquitous enzyme, dipeptidyl peptidase IV (DPP IV) cleaves N-terminally, removing a dipeptide and thereby inactivating both peptides, because the N-terminus is crucial for receptor binding. Subsequently, the peptides may be degraded by other enzymes and extracted in an organ-specific manner. The intact peptides are inactivated during passage across the hepatic bed and further metabolised by the peripheral tissues, while the kidney is important for the final elimination of the metabolites.

Crystal Structure of the Minor Pilin CofB, the Initiator of CFA/III Pilus Assembly in Enterotoxigenic Escherichia coli*

PubMed Central

Kolappan, Subramania; Ng, Dixon; Yang, Guixiang; Harn, Tony; Craig, Lisa

2015-01-01

Type IV pili are extracellular polymers of the major pilin subunit. These subunits are held together in the pilus filament by hydrophobic interactions among their N-terminal α-helices, which also anchor the pilin subunits in the inner membrane prior to pilus assembly. Type IV pilus assembly involves a conserved group of proteins that span the envelope of Gram-negative bacteria. Among these is a set of minor pilins, so named because they share their hydrophobic N-terminal polymerization/membrane anchor segment with the major pilins but are much less abundant. Minor pilins influence pilus assembly and retraction, but their precise functions are not well defined. The Type IV pilus systems of enterotoxigenic Escherichia coli and Vibrio cholerae are among the simplest of Type IV pilus systems and possess only a single minor pilin. Here we show that the enterotoxigenic E. coli minor pilins CofB and LngB are required for assembly of their respective Type IV pili, CFA/III and Longus. Low levels of the minor pilins are optimal for pilus assembly, and CofB can be detected in the pilus fraction. We solved the 2.0 Å crystal structure of N-terminally truncated CofB, revealing a pilin-like protein with an extended C-terminal region composed of two discrete domains connected by flexible linkers. The C-terminal region is required for CofB to initiate pilus assembly. We propose a model for CofB-initiated pilus assembly with implications for understanding filament growth in more complex Type IV pilus systems as well as the related Type II secretion system. PMID:26324721

Crystal Structure of the Minor Pilin CofB, the Initiator of CFA/III Pilus Assembly in Enterotoxigenic Escherichia coli.

PubMed

Kolappan, Subramania; Ng, Dixon; Yang, Guixiang; Harn, Tony; Craig, Lisa

2015-10-23

Type IV pili are extracellular polymers of the major pilin subunit. These subunits are held together in the pilus filament by hydrophobic interactions among their N-terminal α-helices, which also anchor the pilin subunits in the inner membrane prior to pilus assembly. Type IV pilus assembly involves a conserved group of proteins that span the envelope of Gram-negative bacteria. Among these is a set of minor pilins, so named because they share their hydrophobic N-terminal polymerization/membrane anchor segment with the major pilins but are much less abundant. Minor pilins influence pilus assembly and retraction, but their precise functions are not well defined. The Type IV pilus systems of enterotoxigenic Escherichia coli and Vibrio cholerae are among the simplest of Type IV pilus systems and possess only a single minor pilin. Here we show that the enterotoxigenic E. coli minor pilins CofB and LngB are required for assembly of their respective Type IV pili, CFA/III and Longus. Low levels of the minor pilins are optimal for pilus assembly, and CofB can be detected in the pilus fraction. We solved the 2.0 Å crystal structure of N-terminally truncated CofB, revealing a pilin-like protein with an extended C-terminal region composed of two discrete domains connected by flexible linkers. The C-terminal region is required for CofB to initiate pilus assembly. We propose a model for CofB-initiated pilus assembly with implications for understanding filament growth in more complex Type IV pilus systems as well as the related Type II secretion system. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Brucella Modulates Secretory Trafficking via Multiple Type IV Secretion Effector Proteins

PubMed Central

Myeni, Sebenzile; Child, Robert; Ng, Tony W.; Kupko, John J.; Wehrly, Tara D.; Porcella, Stephen F.; Knodler, Leigh A.; Celli, Jean

2013-01-01

The intracellular pathogenic bacterium Brucella generates a replicative vacuole (rBCV) derived from the endoplasmic reticulum via subversion of the host cell secretory pathway. rBCV biogenesis requires the expression of the Type IV secretion system (T4SS) VirB, which is thought to translocate effector proteins that modulate membrane trafficking along the endocytic and secretory pathways. To date, only a few T4SS substrates have been identified, whose molecular functions remain unknown. Here, we used an in silico screen to identify putative T4SS effector candidate proteins using criteria such as limited homology in other bacterial genera, the presence of features similar to known VirB T4SS effectors, GC content and presence of eukaryotic-like motifs. Using β-lactamase and CyaA adenylate cyclase reporter assays, we identified eleven proteins translocated into host cells by Brucella, five in a VirB T4SS-dependent manner, namely BAB1_0678 (BspA), BAB1_0712 (BspB), BAB1_0847 (BspC), BAB1_1671 (BspE) and BAB1_1948 (BspF). A subset of the translocated proteins targeted secretory pathway compartments when ectopically expressed in HeLa cells, and the VirB effectors BspA, BspB and BspF inhibited protein secretion. Brucella infection also impaired host protein secretion in a process requiring BspA, BspB and BspF. Single or combined deletions of bspA, bspB and bspF affected Brucella ability to replicate in macrophages and persist in the liver of infected mice. Taken together, these findings demonstrate that Brucella modulates secretory trafficking via multiple T4SS effector proteins that likely act coordinately to promote Brucella pathogenesis. PMID:23950720

Protease-Activated Receptor 2, Dipeptidyl Peptidase I, and Proteases Mediate Clostridium difficile Toxin A Enteritis

PubMed Central

COTTRELL, GRAEME S.; AMADESI, SILVIA; PIKIOS, STELLA; CAMERER, ERIC; WILLARDSEN, J. ADAM; MURPHY, BRETT R.; CAUGHEY, GEORGE H.; WOLTERS, PAUL J.; COUGHLIN, SHAUN R.; PETERSON, ANDERS; KNECHT, WOLFGANG; POTHOULAKIS, CHARALABOS; BUNNETT, NIGEL W.; GRADY, EILEEN F.

2008-01-01

Background & Aims We studied the role of protease-activated receptor 2 (PAR2) and its activating enzymes, trypsins and tryptase, in Clostridium difficile toxin A (TxA)-induced enteritis. Methods We injected TxA into ileal loops in PAR2 or dipeptidyl peptidase I (DPPI) knockout mice or in wild-type mice pretreated with tryptase inhibitors (FUT-175 or MPI-0442352) or soybean trypsin inhibitor. We examined the effect of TxA on expression and activity of PAR2 and trypsin IV messenger RNA in the ileum and cultured colonocytes. We injected activating peptide (AP), trypsins, tryptase, and p23 in wild-type mice, some pretreated with the neurokinin 1 receptor antagonist SR140333. Results TxA increased fluid secretion, myeloperoxidase activity in fluid and tissue, and histologic damage. PAR2 deletion decreased TxA-induced ileitis, reduced luminal fluid secretion by 20%, decreased tissue and fluid myeloperoxidase by 50%, and diminished epithelial damage, edema, and neutrophil infiltration. DPPI deletion reduced secretion by 20% and fluid myeloperoxidase by 55%. In wild-type mice, FUT-175 or MPI-0442352 inhibited secretion by 24%−28% and tissue and fluid myeloperoxidase by 31%−71%. Soybean trypsin inhibitor reduced secretion to background levels and tissue myeloperoxidase by up to 50%. TxA increased expression of PAR2 and trypsin IV in enterocytes and colonocytes and caused a 2-fold increase in Ca2+ responses to PAR2 AP. AP, tryptase, and trypsin isozymes (trypsin I/II, trypsin IV, p23) caused ileitis. SR140333 prevented AP-induced ileitis. Conclusions PAR2 and its activators are proinflammatory in TxA-induced enteritis. TxA stimulates existing PAR2 and up-regulates PAR2 and activating proteases, and PAR2 causes inflammation by neurogenic mechanisms. PMID:17570216

The 2.5 Å Structure of the Enterococcus Conjugation Protein TraM resembles VirB8 Type IV Secretion Proteins*

PubMed Central

Goessweiner-Mohr, Nikolaus; Grumet, Lukas; Arends, Karsten; Pavkov-Keller, Tea; Gruber, Christian C.; Gruber, Karl; Birner-Gruenberger, Ruth; Kropec-Huebner, Andrea; Huebner, Johannes; Grohmann, Elisabeth; Keller, Walter

2013-01-01

Conjugative plasmid transfer is the most important means of spreading antibiotic resistance and virulence genes among bacteria and therefore presents a serious threat to human health. The process requires direct cell-cell contact made possible by a multiprotein complex that spans cellular membranes and serves as a channel for macromolecular secretion. Thus far, well studied conjugative type IV secretion systems (T4SS) are of Gram-negative (G−) origin. Although many medically relevant pathogens (e.g., enterococci, staphylococci, and streptococci) are Gram-positive (G+), their conjugation systems have received little attention. This study provides structural information for the transfer protein TraM of the G+ broad host range Enterococcus conjugative plasmid pIP501. Immunolocalization demonstrated that the protein localizes to the cell wall. We then used opsonophagocytosis as a novel tool to verify that TraM was exposed on the cell surface. In these assays, antibodies generated to TraM recruited macrophages and enabled killing of pIP501 harboring Enteroccocus faecalis cells. The crystal structure of the C-terminal, surface-exposed domain of TraM was determined to 2.5 Å resolution. The structure, molecular dynamics, and cross-linking studies indicated that a TraM trimer acts as the biological unit. Despite the absence of sequence-based similarity, TraM unexpectedly displayed a fold similar to the T4SS VirB8 proteins from Agrobacterium tumefaciens and Brucella suis (G−) and to the transfer protein TcpC from Clostridium perfringens plasmid pCW3 (G+). Based on the alignments of secondary structure elements of VirB8-like proteins from mobile genetic elements and chromosomally encoded T4SS from G+ and G− bacteria, we propose a new classification scheme of VirB8-like proteins. PMID:23188825

Outer Membrane Targeting, Ultrastructure, and Single Molecule Localization of the Enteropathogenic Escherichia coli Type IV Pilus Secretin BfpB

PubMed Central

Lieberman, Joshua A.; Frost, Nicholas A.; Hoppert, Michael; Fernandes, Paula J.; Vogt, Stefanie L.; Raivio, Tracy L.; Blanpied, Thomas A.

2012-01-01

Type IV pili (T4P) are filamentous surface appendages required for tissue adherence, motility, aggregation, and transformation in a wide array of bacteria and archaea. The bundle-forming pilus (BFP) of enteropathogenic Escherichia coli (EPEC) is a prototypical T4P and confirmed virulence factor. T4P fibers are assembled by a complex biogenesis machine that extrudes pili through an outer membrane (OM) pore formed by the secretin protein. Secretins constitute a superfamily of proteins that assemble into multimers and support the transport of macromolecules by four evolutionarily ancient secretion systems: T4P, type II secretion, type III secretion, and phage assembly. Here, we determine that the lipoprotein transport pathway is not required for targeting the BfpB secretin protein of the EPEC T4P to the OM and describe the ultrastructure of the single particle averaged structures of the assembled complex by transmission electron microscopy. Furthermore, we use photoactivated localization microscopy to determine the distribution of single BfpB molecules fused to photoactivated mCherry. In contrast to findings in other T4P systems, we found that BFP components predominantly have an uneven distribution through the cell envelope and are only found at one or both poles in a minority of cells. In addition, we report that concurrent mutation of both the T4bP secretin and the retraction ATPase can result in viable cells and found that these cells display paradoxically low levels of cell envelope stress response activity. These results imply that secretins can direct their own targeting, have complex distributions and provide feedback information on the state of pilus biogenesis. PMID:22247509

Bacillus Calmette-Guérin enhances production and secretion of type IV collagenases in peripheral blood mononuclear cells.

PubMed

Kageyama, Y; Kawakami, S; Fujii, Y; Kihara, K; Oshima, H

1997-03-01

Intravesical administration of bacillus Calmette-Guérin (BCG) is an effective and widely accepted treatment for superficial bladder cancer. Rapid progression of the disease after BCG therapy, however, has been reported in some cases refractory to the treatment. We examined whether BCG treatment and coexistence of peripheral blood mononuclear cells (PBMCs) alter the invasive potential of bladder cancer cells. Production and secretion of two type IV collagenases, matrix metalloproteinase (MMP) 2 and MMP 9, by PBMCs from five healthy donors or bladder cancer cells (T24, JTC 30, and JTC 32) were evaluated by gelatin zymography, western blot analysis, and northern blot analysis. Invasion of bladder cancer cells was also examined using reconstituted basement membrane (Matrigel). BCG (5, 50, and 500 micrograms/ml) had no effect on secretion of MMP 2 and MMP 9 by bladder cancer cells, but increased the production and secretion of MMP 9 by PBMCs in a dose-dependent manner. The coexistence of PBMCs increased invasion of T24 cells and BCG further enhanced the invasion. Thus, BCG promotes invasion of bladder cancer cells under certain conditions. An increase in the secretion of MMP 9 by PBMCs may account in part for the effect.

Biochemistry of plant class IV chitinases and fungal chitinase-modifying proteins

USDA-ARS?s Scientific Manuscript database

Plant class IV chitinases have 2 domains, a small (3 kDa) amino-terminal domain with homology to carbohydrate binding peptides, and a larger (25 kDa) catalytic domain. The biological function of these chitinases is not known. But it is known that some pathogenic fungi secrete chitinase modifying pro...

Polyglycine hydrolases secreted by Pleosporineae fungi that target the linker region of plant class IV chitinases*

USDA-ARS?s Scientific Manuscript database

Chitinase modifying proteins (cmps) are fungal proteases that truncate plant class IV chitinases by cleaving near their amino termini. We previously described Fv-cmp, a fungalysin protease that cleaves a conserved glycine-cysteine bond within the hevein domain. Here we describe a new type of cmp—pol...

Antimicrobial peptide inhibition of fungalysin proteases that target plant type 19 Family IV defense chitinases

USDA-ARS?s Scientific Manuscript database

Cereal crops and other plants produce secreted seed chitinases that reduce pathogenic infection, most likely by targeting the fungal chitinous cell wall. We have shown that corn (Zea mays) produces three GH family 19, plant class IV chitinases, that help in protecting the plant against Fusarium and ...

The Effect of Different Doses of X-Irradiation on the Corticosteroid Secretion in Rabbits USSR.

DTIC Science & Technology

1960-06-30

Tuul1 in Patolog ;. Fi2iol. 1 Eksper, Terapiya (Patho- logical Physiology and Experimental Therapy)» Vol. IV, No. 1, I960» p&gss 24-28. — Fron the... relationship of the changes in the nature of secretion of corticosteroids observed after irradiation to the degree of radiation injury we nade an...studying the relationship of the rate of secretion of the various cortical hormones to the magnitude of the dose received by the rabbits

Steps in the development of a Vibrio cholerae El Tor biofilm

PubMed Central

Watnick, Paula I.; Kolter, Roberto

2010-01-01

Summary We report that, in a simple, static culture system, wild-type Vibrio cholerae El Tor forms a three-dimensional biofilm with characteristic water channels and pillars of bacteria. Furthermore, we have isolated and characterized transposon insertion mutants of V. cholerae that are defective in biofilm development. The transposons were localized to genes involved in (i) the biosynthesis and secretion of the mannose-sensitive haemagglutinin type IV pilus (MSHA); (ii) the synthesis of exopolysaccharide; and (iii) flagellar motility. The phenotypes of these three groups suggest that the type IV pilus and flagellum accelerate attachment to the abiotic surface, the flagellum mediates spread along the abiotic surface, and exopolysaccharide is involved in the formation of three-dimensional biofilm architecture. PMID:10564499

Mechanism and function of type IV secretion during infection of the human host

PubMed Central

Gonzalez-Rivera, Christian; Bhatty, Minny; Christie, Peter J.

2015-01-01

Bacterial pathogens employ type IV secretion systems (T4SSs) for various purposes to aid in survival and proliferation in eukaryotic host. One large T4SS subfamily, the conjugation systems, confers a selective advantage to the invading pathogen in clinical settings through dissemination of antibiotic resistance genes and virulence traits. Besides their intrinsic importance as principle contributors to the emergence of multiply drug-resistant ‘superbugs’, detailed studies of these highly tractable systems have generated important new insights into the mode of action and architectures of paradigmatic T4SSs as a foundation for future efforts aimed at suppressing T4SS machine function. Over the past decade, extensive work on the second large T4SS subfamily, the effector translocators, has identified a myriad of mechanisms employed by pathogens to subvert, subdue, or bypass cellular processes and signaling pathways of the host cell. An overarching theme in the evolution of many effectors is that of molecular mimicry. These effectors carry domains similar to those of eukaryotic proteins and exert their effects through stealthy interdigitation of cellular pathways, often with the outcome not of inducing irreversible cell damage but rather of reversibly modulating cellular functions. This chapter summarizes the major developments for the actively studied pathogens with an emphasis on the structural and functional diversity of the T4SSs and the emerging common themes surrounding effector function in the human host. PMID:27337453

NOD1 is required for Helicobacter pylori induction of IL-33 responses in gastric epithelial cells.

PubMed

Tran, Le Son; Tran, Darren; De Paoli, Amanda; D'Costa, Kimberley; Creed, Sarah J; Ng, Garrett Z; Le, Lena; Sutton, Philip; Silke, J; Nachbur, U; Ferrero, Richard L

2018-05-01

Helicobacter pylori (H. pylori) causes chronic inflammation which is a key precursor to gastric carcinogenesis. It has been suggested that H. pylori may limit this immunopathology by inducing the production of interleukin 33 (IL-33) in gastric epithelial cells, thus promoting T helper 2 immune responses. The molecular mechanism underlying IL-33 production in response to H. pylori infection, however, remains unknown. In this study, we demonstrate that H. pylori activates signalling via the pathogen recognition molecule Nucleotide-Binding Oligomerisation Domain-Containing Protein 1 (NOD1) and its adaptor protein receptor-interacting serine-threonine Kinase 2, to promote production of both full-length and processed IL-33 in gastric epithelial cells. Furthermore, IL-33 responses were dependent on the actions of the H. pylori Type IV secretion system, required for activation of the NOD1 pathway, as well as on the Type IV secretion system effector protein, CagA. Importantly, Nod1 +/+ mice with chronic H. pylori infection exhibited significantly increased gastric IL-33 and splenic IL-13 responses, but decreased IFN-γ responses, when compared with Nod1 -/- animals. Collectively, our data identify NOD1 as an important regulator of mucosal IL-33 responses in H. pylori infection. We suggest that NOD1 may play a role in protection against excessive inflammation. © 2018 John Wiley & Sons Ltd.

Draft genome sequence for virulent and avirulent strains of Xanthomonas arboricola isolated from Prunus spp. in Spain.

PubMed

Garita-Cambronero, Jerson; Palacio-Bielsa, Ana; López, María M; Cubero, Jaime

2016-01-01

Xanthomonas arboricola is a species in genus Xanthomonas which is mainly comprised of plant pathogens. Among the members of this taxon, X. arboricola pv. pruni, the causal agent of bacterial spot disease of stone fruits and almond, is distributed worldwide although it is considered a quarantine pathogen in the European Union. Herein, we report the draft genome sequence, the classification, the annotation and the sequence analyses of a virulent strain, IVIA 2626.1, and an avirulent strain, CITA 44, of X. arboricola associated with Prunus spp. The draft genome sequence of IVIA 2626.1 consists of 5,027,671 bp, 4,720 protein coding genes and 50 RNA encoding genes. The draft genome sequence of strain CITA 44 consists of 4,760,482 bp, 4,250 protein coding genes and 56 RNA coding genes. Initial comparative analyses reveals differences in the presence of structural and regulatory components of the type IV pilus, the type III secretion system, the type III effectors as well as variations in the number of the type IV secretion systems. The genome sequence data for these strains will facilitate the development of molecular diagnostics protocols that differentiate virulent and avirulent strains. In addition, comparative genome analysis will provide insights into the plant-pathogen interaction during the bacterial spot disease process.

Cag3 Is a Novel Essential Component of the Helicobacter pylori Cag Type IV Secretion System Outer Membrane Subcomplex ▿ †

PubMed Central

Pinto-Santini, Delia M.; Salama, Nina R.

2009-01-01

Helicobacter pylori strains harboring the cag pathogenicity island (PAI) have been associated with more severe gastric disease in infected humans. The cag PAI encodes a type IV secretion (T4S) system required for CagA translocation into host cells as well as induction of proinflammatory cytokines, such as interleukin-8 (IL-8). cag PAI genes sharing sequence similarity with T4S components from other bacteria are essential for Cag T4S function. Other cag PAI-encoded genes are also essential for Cag T4S, but lack of sequence-based or structural similarity with genes in existing databases has precluded a functional assignment for the encoded proteins. We have studied the role of one such protein, Cag3 (HP0522), in Cag T4S and determined Cag3 subcellular localization and protein interactions. Cag3 is membrane associated and copurifies with predicted inner and outer membrane Cag T4S components that are essential for Cag T4S as well as putative accessory factors. Coimmunoprecipitation and cross-linking experiments revealed specific interactions with HpVirB7 and CagM, suggesting Cag3 is a new component of the Cag T4S outer membrane subcomplex. Finally, lack of Cag3 lowers HpVirB7 steady-state levels, further indicating Cag3 makes a subcomplex with this protein. PMID:19801411

Analysis of the Legionella longbeachae Genome and Transcriptome Uncovers Unique Strategies to Cause Legionnaires' Disease

PubMed Central

Rusniok, Christophe; Lomma, Mariella; Dervins-Ravault, Delphine; Newton, Hayley J.; Sansom, Fiona M.; Jarraud, Sophie; Zidane, Nora; Ma, Laurence; Bouchier, Christiane; Etienne, Jerôme; Hartland, Elizabeth L.; Buchrieser, Carmen

2010-01-01

Legionella pneumophila and L. longbeachae are two species of a large genus of bacteria that are ubiquitous in nature. L. pneumophila is mainly found in natural and artificial water circuits while L. longbeachae is mainly present in soil. Under the appropriate conditions both species are human pathogens, capable of causing a severe form of pneumonia termed Legionnaires' disease. Here we report the sequencing and analysis of four L. longbeachae genomes, one complete genome sequence of L. longbeachae strain NSW150 serogroup (Sg) 1, and three draft genome sequences another belonging to Sg1 and two to Sg2. The genome organization and gene content of the four L. longbeachae genomes are highly conserved, indicating strong pressure for niche adaptation. Analysis and comparison of L. longbeachae strain NSW150 with L. pneumophila revealed common but also unexpected features specific to this pathogen. The interaction with host cells shows distinct features from L. pneumophila, as L. longbeachae possesses a unique repertoire of putative Dot/Icm type IV secretion system substrates, eukaryotic-like and eukaryotic domain proteins, and encodes additional secretion systems. However, analysis of the ability of a dotA mutant of L. longbeachae NSW150 to replicate in the Acanthamoeba castellanii and in a mouse lung infection model showed that the Dot/Icm type IV secretion system is also essential for the virulence of L. longbeachae. In contrast to L. pneumophila, L. longbeachae does not encode flagella, thereby providing a possible explanation for differences in mouse susceptibility to infection between the two pathogens. Furthermore, transcriptome analysis revealed that L. longbeachae has a less pronounced biphasic life cycle as compared to L. pneumophila, and genome analysis and electron microscopy suggested that L. longbeachae is encapsulated. These species-specific differences may account for the different environmental niches and disease epidemiology of these two Legionella species. PMID:20174605

General pharmacological profile of the novel muscarinic receptor agonist SNI-2011, a drug for xerostomia in Sjögren's syndrome. 4th communication: Effects on gastrointestinal, urinary and reproductive systems and other effects.

PubMed

Arisawa, Hirohiko; Fukui, Kenji; Imai, Eiichi; Fujise, Nobuaki; Masunaga, Hiroaki

2002-01-01

A novel muscarinic receptor agonist, SNI-2011 ((+/-)-cis-2-methylspiro[1,3-oxathiolane-5,3'-quinuclidine] monohydrochloride hemihydrate, cevimeline, CAS 153504-70-2), is a candidate therapeutic drug for xerostomia in Sjögren's syndrome. The general pharmacological properties of this drug on the gastrointestinal, urinary and reproductive systems and other tissues were investigated in mice, rats guinea pigs, rabbits and dogs. 1. Gastrointestinal system: SNI-2011 did not cause any effects on the gastrointestinal system, i.e. the intestinal transport of charcoal meal in mice, the secretion of gastric and bile juices, and the formation of ulcer induced by water immersion restraint in rats. 2. Urinary and reproductive systems: SNI-2011 augmented the spontaneous movement of rat pregnant uterus in vivo at 0.3 mg/kg i.v. or higher, and this effect was not observed in the non-pregnant uterus. SNI-2011 increased the spontaneous movement of isolated guinea pig bladder (3 x 10(-6) mol/l or higher) and increased the in vivo spontaneous movement of rat bladder (0.3 mg/kg i.v. or higher). SNI-2011 caused increases in rat urine volume, pH and urinary excretion of Na+ and Cl- at 30 mg/kg p.o. 3. Others: SNI-2011 had no effect on the vascular permeability in mice, hematological parameters and blood coagulation in rats. SNI-2011 had neither hemolytic nor anti-inflammatory effect. These results suggest that SNI-2011 has muscarinic effects on the gastrointestinal, urinary and reproductive systems and other tissues at the doses approximately 10-fold higher than the doses needed for saliva secretion.

A bipartite signal mediates the transfer of type IV secretion substrates of Bartonella henselae into human cells

PubMed Central

Schulein, Ralf; Guye, Patrick; Rhomberg, Thomas A.; Schmid, Michael C.; Schröder, Gunnar; Vergunst, Annette C.; Carena, Ilaria; Dehio, Christoph

2005-01-01

Bacterial type IV secretion (T4S) systems mediate the transfer of macromolecular substrates into various target cells, e.g., the conjugative transfer of DNA into bacteria or the transfer of virulence proteins into eukaryotic host cells. The T4S apparatus VirB of the vascular tumor-inducing pathogen Bartonella henselae causes subversion of human endothelial cell (HEC) function. Here we report the identification of multiple protein substrates of VirB, which, upon translocation into HEC, mediate all known VirB-dependent cellular changes. These Bartonella-translocated effector proteins (Beps) A-G are encoded together with the VirB system and the T4S coupling protein VirD4 on a Bartonella-specific pathogenicity island. The Beps display a modular architecture, suggesting an evolution by extensive domain duplication and reshuffling. The C terminus of each Bep harbors at least one copy of the Bep-intracellular delivery domain and a short positively charged tail sequence. This biparte C terminus constitutes a transfer signal that is sufficient to mediate VirB/VirD4-dependent intracellular delivery of reporter protein fusions. The Bep-intracellular delivery domain is also present in conjugative relaxases of bacterial conjugation systems. We exemplarily show that the C terminus of such a conjugative relaxase mediates protein transfer through the Bartonella henselae VirB/VirD4 system into HEC. Conjugative relaxases may thus represent the evolutionary origin of the here defined T4S signal for protein transfer into human cells. PMID:15642951

Galanin does not affect the growth hormone-releasing hormone-stimulated growth hormone secretion in patients with hyperthyroidism.

PubMed

Giustina, A; Bussi, A R; Legati, F; Bossoni, S; Licini, M; Schettino, M; Zuccato, F; Wehrenberg, W B

1992-12-01

Patients with hyperthyroidism have reduced spontaneous and stimulated growth hormone (GH) secretion. The aim of our study was to evaluate the effects of galanin, a novel neuropeptide which stimulates GH secretion in man, on the GH response to GHRH in patients with hyperthyroidism. Eight untreated hyperthyroid patients with Graves' disease (6F, 2M, aged 25-50 years) and six healthy volunteers (3F, 3M, aged 27-76 years) underwent from -10 to 30 min in random order: (i) porcine galanin, iv, 500 micrograms in 100 ml saline; or (ii) saline, iv, 100 ml. A bolus of human GHRH(1-29)NH2, 100 micrograms, was injected iv at 0 min. Hyperthyroid patients showed blunted GH peaks after GHRH+saline (10.2 +/- 2.5 micrograms/l) compared to normal subjects (20.7 +/- 4.8 micrograms/l, p < 0.05). GH peaks after GHRH+galanin were also significantly lower in hyperthyroid subjects (12.5 +/- 3 micrograms/l) compared to normal subjects (43.8 +/- 6 micrograms/l, p < 0.05). That galanin is not able to reverse the blunted GH response to GHRH in hyperthyroidism suggests that hyperthyroxinemia may either increase the somatostatin release by the hypothalamus or directly affect the pituitary GH secretory capacity.

[The effect of bombesin and its analogs on the secretion of gastric juice and its content of pepsin and hydrochloric acid].

PubMed

Barashkova, G M; Klimov, P K; Kuranova, I L; Churkina, S I; Filonova, E B

1990-07-01

I.V. Infusion of bombesine after eating raw meat inhibited for 30-60 min the secretion of gastric juice and hydrochloric acid in dogs. Within 90-120 min of simultaneous infusion of pentagastrin and bombesine, the amount of secreted juice and its acidity decreased and then the secretion of gastric parietal cells increased. Simultaneous infusion of histamine and bombesine increased the response of gastric parietal cells during the whole experiment as compared with the histamine effect alone. Microapplication of bombesine into cerebral structures also decreased the secretory response of the parietal cells.

Abundance of truncated and full-length ChitA and ChitB chitinases in healthy and diseased maize tissues

USDA-ARS?s Scientific Manuscript database

Chitinase modifying proteins, cmps, are secreted fungal proteases that combat plant defenses by truncating plant class IV chitinases. We initially discovered that ChitA and ChitB, two plant class IV chitinases that are abundant in developing and mature kernels of corn, are truncated by cmps during e...

Cloning and identification of Fv-cmp, a protease from Fusarium verticillioides that truncates Zea mays and Arabidopsis thaliana class IV chitinases

USDA-ARS?s Scientific Manuscript database

Chitinase modifying proteins (cmps) are proteases, secreted by fungal pathogens, that were originally identified as proteins that truncate class IV chitinases of maize during ear rot. Cmps from Bipolaris zeicola and Stenocarpella maydis have been characterized, but the identities of the proteases h...

Feasibility of Repairing Glomerular Basement Membrane Defects in Alport Syndrome

PubMed Central

Lin, Xiaobo; Suh, Jung Hee; Go, Gloriosa

2014-01-01

Alport syndrome is a hereditary glomerular disease that leads to kidney failure. It is caused by mutations affecting one of three chains of the collagen α3α4α5(IV) heterotrimer, which forms the major collagen IV network of the glomerular basement membrane (GBM). In the absence of the α3α4α5(IV) network, the α1α1α2(IV) network substitutes, but it is insufficient to maintain normal kidney function. Inhibition of angiotensin-converting enzyme slows progression to kidney failure in patients with Alport syndrome but is not a cure. Restoration of the normal collagen α3α4α5(IV) network in the GBM, by either cell- or gene-based therapy, is an attractive and logical approach toward a cure, but whether or not the abnormal GBM can be repaired once it has formed and is functioning is unknown. Using a mouse model of Alport syndrome and an inducible transgene system, we found that secretion of α3α4α5(IV) heterotrimers by podocytes into a preformed, abnormal, filtering Alport GBM is effective at restoring the missing collagen IV network, slowing kidney disease progression, and extending life span. This proof-of-principle study demonstrates the plasticity of the mature GBM and validates the pursuit of therapeutic approaches aimed at normalizing the GBM to prolong kidney function. PMID:24262794

Feasibility of repairing glomerular basement membrane defects in Alport syndrome.

PubMed

Lin, Xiaobo; Suh, Jung Hee; Go, Gloriosa; Miner, Jeffrey H

2014-04-01

Alport syndrome is a hereditary glomerular disease that leads to kidney failure. It is caused by mutations affecting one of three chains of the collagen α3α4α5(IV) heterotrimer, which forms the major collagen IV network of the glomerular basement membrane (GBM). In the absence of the α3α4α5(IV) network, the α1α1α2(IV) network substitutes, but it is insufficient to maintain normal kidney function. Inhibition of angiotensin-converting enzyme slows progression to kidney failure in patients with Alport syndrome but is not a cure. Restoration of the normal collagen α3α4α5(IV) network in the GBM, by either cell- or gene-based therapy, is an attractive and logical approach toward a cure, but whether or not the abnormal GBM can be repaired once it has formed and is functioning is unknown. Using a mouse model of Alport syndrome and an inducible transgene system, we found that secretion of α3α4α5(IV) heterotrimers by podocytes into a preformed, abnormal, filtering Alport GBM is effective at restoring the missing collagen IV network, slowing kidney disease progression, and extending life span. This proof-of-principle study demonstrates the plasticity of the mature GBM and validates the pursuit of therapeutic approaches aimed at normalizing the GBM to prolong kidney function.

Inhibition of physiological growth hormone secretion by atropine.

PubMed

Taylor, B J; Smith, P J; Brook, C G

1985-04-01

We have investigated the effects of atropine (specific muscarinic cholinergic inhibition) on the nocturnal secretion of GH during the first cycle of stage IV sleep in six normal volunteers and three tall adolescents. Atropine was administered orally in a dose of 0.6 mg (n = 8) or 1.8 mg (n = 4) 30 min before expected sleep and the sampling repeated. Peak GH level without atropine was 45.3 mU/l (range 5.7 to 92.0): both doses of atropine abolished sleep associated GH secretion. Spontaneous daytime GH secretion was demonstrated during five 6 h sampling periods in three normal adults. There was a significant decrease in spontaneous daytime GH secretion when the sampling was repeated after atropine 0.6 mg or 1.8 mg. We conclude that inhibition of GH secretion using anticholinergic drugs should be further investigated in the management of excessive growth hormone secretion.

Assessment of the effects of feed restriction and amino acid supplementation on glucose tolerance in llamas.

PubMed

Cebra, Christopher K; Tornquist, Susan J; Jester, Rebecca M; Stelletta, Calogero

2004-07-01

To assess the effects of prolonged feed deprivation on glucose tolerance, insulin secretion, and lipid homeostasis in llamas. 9 adult female llamas. On each of 2 consecutive days, food was withheld from the llamas for 8 hours. Blood samples were collected before and 5, 15, 30, 45, 60, 120, and 240 minutes after IV injection of dextrose (0.5 g/kg) for determination of plasma insulin and serum glucose, triglyceride, and nonesterified fatty acid concentrations. Between experimental periods, the llamas received supplemental amino acids IV (185 mg/kg in solution). The llamas were then fed a limited diet (grass hay, 0.25% of body weight daily) for 23 days, after which the experimental procedures were repeated. Feed restriction decreased glucose tolerance and had slight effects on insulin secretion in llamas. Basal lipid fractions were higher after feed restriction, but dextrose administration resulted in similar reductions in serum lipid concentrations with and without feed restriction. Insulin secretion was decreased on the second day of each study period, which lessened reduction of serum lipid concentrations but did not affect glucose tolerance. Despite having a comparatively competent pancreatic response, feed-restricted llamas assimilated dextrose via an IV bolus more slowly than did llamas on full rations. However, repeated administration of dextrose reduced insulin secretion and could promote hyperglycemia and fat mobilization. These findings suggested that veterinarians should use alternative methods of supplying energy to camelids with long-term reduced feed intake or consider administering agents to improve the assimilation of glucose.

Effect of the glucocorticoid receptor antagonist Org 34850 on fast and delayed feedback of corticosterone release.

PubMed

Spiga, Francesca; Harrison, Louise R; Wood, Susan A; MacSweeney, Cliona P; Thomson, Fiona J; Craighead, Mark; Grassie, Morag; Lightman, Stafford L

2008-02-01

We investigated the effect of the glucocorticoid receptor (GR) antagonist Org 34850 on fast and delayed inhibition of corticosterone secretion in response to the synthetic glucocorticoid methylprednisolone (MPL). Male rats were implanted with a catheter in the right jugular vein, for blood sampling and MPL administration, and with an s.c. cannula for Org 34850 administration. All experiments were conducted at the diurnal hormonal peak in the late afternoon. Rats were connected to an automated sampling system and blood samples were collected every 5 or 10 min. Org 34850 (10 mg/kg, s.c.) or vehicle (5% mulgofen in saline) was injected at 1630 h; 30 min later, rats received an injection of MPL (500 microg/rat, i.v.) or saline (0.1 ml/rat). We found that an acute administration of MPL rapidly decreased the basal corticosterone secretion and this effect was not prevented by acute pretreatment with Org 34850. However, blockade of GR with Org 34850 prevented delayed inhibition of MPL on corticosterone secretion measured between 4 and 12 h after MPL administration. Our data suggest an involvement of GR in modulating delayed, but not fast, inhibition induced by MPL on basal corticosterone secretion.

Characterization and synthesis of volatile compounds from the defensive secretions of some "daddy longlets" (Arachnida: Opiliones: Leiobunum spp.).

PubMed

Jones, T H; Meinwald, J; Hicks, K; Eisner, T

1977-02-01

Analyses of the chief volatile constituents of the defensive secretions of three oplionids were carried out. Leiobunum nigripalpi produces three closely related C7 compounds: E-4-methyl-4-hexen-3-one(I), 4-methylhexan-3-one(II), and 4-methylhexan-3-ol(III), along with E-4-methyl-4-hepten-3-one(IV), E,E-2,4-dimethylhexa-2,4-dienal(IX), and a minor, unidentified component. L. leiopenis secretion contains E-4-methyl-4-hepten-3-one(IV), 4-methylheptan-3-one(V), E,E-2,4-dimethylhexa-2,4-dien-1-ol(VII), and E,E-2,4-dimethylhepta-2,4-dien-1-ol(VIII). L. calcar yields chiefly E-4,6-dimethyl-6-octen-3-one(VI) and E,E-2,4-dimethylhexa-2,4-dien-1-ol(VII). Six of these compounds are new natural products. The structures of these compounds, which can be regarded either as polyketide-derived or as modified isoprenoids, raise interesting biosynthetic questions.

Characterization and synthesis of volatile compounds from the defensive secretions of some "daddy longlets" (Arachnida: Opiliones: Leiobunum spp.).

PubMed Central

Jones, T H; Meinwald, J; Hicks, K; Eisner, T

1977-01-01

Analyses of the chief volatile constituents of the defensive secretions of three oplionids were carried out. Leiobunum nigripalpi produces three closely related C7 compounds: E-4-methyl-4-hexen-3-one(I), 4-methylhexan-3-one(II), and 4-methylhexan-3-ol(III), along with E-4-methyl-4-hepten-3-one(IV), E,E-2,4-dimethylhexa-2,4-dienal(IX), and a minor, unidentified component. L. leiopenis secretion contains E-4-methyl-4-hepten-3-one(IV), 4-methylheptan-3-one(V), E,E-2,4-dimethylhexa-2,4-dien-1-ol(VII), and E,E-2,4-dimethylhepta-2,4-dien-1-ol(VIII). L. calcar yields chiefly E-4,6-dimethyl-6-octen-3-one(VI) and E,E-2,4-dimethylhexa-2,4-dien-1-ol(VII). Six of these compounds are new natural products. The structures of these compounds, which can be regarded either as polyketide-derived or as modified isoprenoids, raise interesting biosynthetic questions. PMID:265514

Effects of phenylbutazone on glucose tolerance and on secretion of insulin in healthy geldings.

PubMed

Zicker, S C; Brumbaugh, G W

1989-05-01

The effect of phenylbutazone (4.4 mg/kg of body weight, IV, q 24 h, for 5 days) on glucose tolerance and on secretion of insulin in 6 healthy geldings was determined. Phenylbutazone significantly lowered fasting concentrations of glucose in plasma but did not significantly change the concentration of insulin in serum. There was no significant effect of phenylbutazone on glucose tolerance, on secretion of insulin, or on the area under the insulin/glucose ratio vs time curve in healthy geldings, as determined by paired t test analysis.

Effect of YM-14673, an analogue of thyrotropin-releasing hormone, on duodenal bicarbonate secretion in the rat.

PubMed

Takeuchi, K; Niida, H; Ueshima, K; Okabe, S

1991-01-01

The effects of YM-14673, an analogue of thyrotropin-releasing hormone, on duodenal HCO3- secretion were characterized in comparison with those of prostaglandin E2 and carbachol in anesthetized rats. The proximal duodenum was perfused with saline (pH 4.5), the pH of the perfusate and of the transmucosal potential difference were continuously monitored, and HCO3- output was determined by back-titration of the perfusate and by pH change. YM-14673 (0.1, 0.3 and 1 mg/kg) increased these parameters in a dose-related manner; the total HCO3- output at 1 mg/kg (5.8 +/- 0.7 mumol) was about 50% of that induced by prostaglandin E2 (1 mg/kg, i.v.) and 2 times greater than that induced by carbachol (4 micrograms/kg, i.v.). These responses, induced by YM-14673, were almost completely blocked by bilateral vagotomy and significantly inhibited by atropine (0.3 mg/kg, i.v.) or cyclooxygenase inhibitors, such as indomethacin (5 mg/kg, s.c.) and acetylsalicylic acid (40 mg/kg, s.c.), but not affected by pirenzepine (1 mg/kg, i.v.), a selective M1 antagonist. None of the latter agents had any effect on the HCO3(-)-stimulating action of prostaglandin E2, while the carbachol-induced HCO3- output was significantly reduced by atropine. These results suggest that YM-14673 induces the vagal-dependent HCO3- secretion in the rat duodenum and that this mechanism is mediated by muscarinic cholinoceptors, excluding the M1-subtype, and may involve endogenous prostaglandins.

Bartonella henselae trimeric autotransporter adhesin BadA expression interferes with effector translocation by the VirB/D4 type IV secretion system.

PubMed

Lu, Yun-Yueh; Franz, Bettina; Truttmann, Matthias C; Riess, Tanja; Gay-Fraret, Jérémie; Faustmann, Marco; Kempf, Volkhard A J; Dehio, Christoph

2013-05-01

The Gram-negative, zoonotic pathogen Bartonella henselae is the aetiological agent of cat scratch disease, bacillary angiomatosis and peliosis hepatis in humans. Two pathogenicity factors of B. henselae - each displaying multiple functions in host cell interaction - have been characterized in greater detail: the trimeric autotransporter Bartonella adhesin A (BadA) and the type IV secretion system VirB/D4 (VirB/D4 T4SS). BadA mediates, e.g. binding to fibronectin (Fn), adherence to endothelial cells (ECs) and secretion of vascular endothelial growth factor (VEGF). VirB/D4 translocates several Bartonella effector proteins (Beps) into the cytoplasm of infected ECs, resulting, e.g. in uptake of bacterial aggregates via the invasome structure, inhibition of apoptosis and activation of a proangiogenic phenotype. Despite this knowledge of the individual activities of BadA or VirB/D4 it is unknown whether these major virulence factors affect each other in their specific activities. In this study, expression and function of BadA and VirB/D4 were analysed in a variety of clinical B. henselae isolates. Data revealed that most isolates have lost expression of either BadA or VirB/D4 during in vitro passages. However, the phenotypic effects of coexpression of both virulence factors was studied in one clinical isolate that was found to stably coexpress BadA and VirB/D4, as well as by ectopic expression of BadA in a strain expressing VirB/D4 but not BadA. BadA, which forms a dense layer on the bacterial surface, negatively affected VirB/D4-dependent Bep translocation and invasome formation by likely preventing close contact between the bacterial cell envelope and the host cell membrane. In contrast, BadA-dependent Fn binding, adhesion to ECs and VEGF secretion were not affected by a functional VirB/D4 T4SS. The obtained data imply that the essential virulence factors BadA and VirB/D4 are likely differentially expressed during different stages of the infection cycle of Bartonella. © 2012 Blackwell Publishing Ltd.

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.

Information Security Program Regulation

DTIC Science & Technology

1986-06-01

above. When an alarmed area is used for the storage of Top Secret material, the physical barrier must be adequate to prevent (a) surreptitious removal ...IV-9 4-304 Removable ADP and Word Processing Storage Media ---------- IV-10 4-305 Documents Produced by ADP Equipment...with a removal or cancellation of the classification designation. 1-315 Declassification Event An event that eliminates the need for continued

Role of Carbohydrate in Glycoprotein Traffic and Secretion

DTIC Science & Technology

1988-01-01

synthesized in normal amounts but accumu- lated intracellularly, with transport to the cell surface being greatly de - layed. Glycoprotein E2 isolated from...UNcLA ,F E 2 Role of Carbohydrate in Glycoprotein Traffic and Secretion JAMES B. PARENT I. Introduction I!. Evidence for Intracellular Transport Signals...Ill. Oligosaccharide Biosynthesis IV. Role of Carbohydrate in Protein Solubility. Structure, and Stability V. Evidence for Carbohydrate Transport

Agrobacterium VirB10, an ATP energy sensor required for type IV secretion.

PubMed

Cascales, Eric; Christie, Peter J

2004-12-07

Bacteria use type IV secretion systems (T4SS) to translocate DNA and protein substrates to target cells of phylogenetically diverse taxa. Recently, by use of an assay termed transfer DNA immunoprecipitation (TrIP), we described the translocation route for a DNA substrate [T-DNA, portion of the Ti (tumor-inducing) plasmid that is transferred to plant cells] of the Agrobacterium tumefaciens VirB/D4 T4SS in terms of a series of temporally and spatially ordered substrate contacts with subunits of the secretion channel. Here, we report that the bitopic inner membrane protein VirB10 undergoes a structural transition in response to ATP utilization by the VirD4 and VirB11 ATP-binding subunits, as monitored by protease susceptibility. VirB10 interacts with inner membrane VirD4 independently of cellular energetic status, whereas the energy-induced conformational change is required for VirB10 complex formation with an outer membrane-associated heterodimer of VirB7 lipoprotein and VirB9, as shown by coimmunoprecipitation. Under these conditions, the T-DNA substrate is delivered from the inner membrane channel components VirB6 and VirB8 to periplasmic and outer membrane-associated VirB2 pilin and VirB9. We propose that VirD4 and VirB11 coordinate the ATP-dependent formation of a VirB10 "bridge" between inner and outer membrane subassemblies of the VirB/D4 T4SS, and that this morphogenetic event is required for T-DNA translocation across the A. tumefaciens cell envelope.

The genome sequence of the facultative intracellular pathogen Brucella melitensis.

PubMed

DelVecchio, Vito G; Kapatral, Vinayak; Redkar, Rajendra J; Patra, Guy; Mujer, Cesar; Los, Tamara; Ivanova, Natalia; Anderson, Iain; Bhattacharyya, Anamitra; Lykidis, Athanasios; Reznik, Gary; Jablonski, Lynn; Larsen, Niels; D'Souza, Mark; Bernal, Axel; Mazur, Mikhail; Goltsman, Eugene; Selkov, Eugene; Elzer, Philip H; Hagius, Sue; O'Callaghan, David; Letesson, Jean-Jacques; Haselkorn, Robert; Kyrpides, Nikos; Overbeek, Ross

2002-01-08

Brucella melitensis is a facultative intracellular bacterial pathogen that causes abortion in goats and sheep and Malta fever in humans. The genome of B. melitensis strain 16M was sequenced and found to contain 3,294,935 bp distributed over two circular chromosomes of 2,117,144 bp and 1,177,787 bp encoding 3,197 ORFs. By using the bioinformatics suite ERGO, 2,487 (78%) ORFs were assigned functions. The origins of replication of the two chromosomes are similar to those of other alpha-proteobacteria. Housekeeping genes, including those involved in DNA replication, transcription, translation, core metabolism, and cell wall biosynthesis, are distributed on both chromosomes. Type I, II, and III secretion systems are absent, but genes encoding sec-dependent, sec-independent, and flagella-specific type III, type IV, and type V secretion systems as well as adhesins, invasins, and hemolysins were identified. Several features of the B. melitensis genome are similar to those of the symbiotic Sinorhizobium meliloti.

The genome sequence of the facultative intracellular pathogen Brucella melitensis

PubMed Central

DelVecchio, Vito G.; Kapatral, Vinayak; Redkar, Rajendra J.; Patra, Guy; Mujer, Cesar; Los, Tamara; Ivanova, Natalia; Anderson, Iain; Bhattacharyya, Anamitra; Lykidis, Athanasios; Reznik, Gary; Jablonski, Lynn; Larsen, Niels; D'Souza, Mark; Bernal, Axel; Mazur, Mikhail; Goltsman, Eugene; Selkov, Eugene; Elzer, Philip H.; Hagius, Sue; O'Callaghan, David; Letesson, Jean-Jacques; Haselkorn, Robert; Kyrpides, Nikos; Overbeek, Ross

2002-01-01

Brucella melitensis is a facultative intracellular bacterial pathogen that causes abortion in goats and sheep and Malta fever in humans. The genome of B. melitensis strain 16M was sequenced and found to contain 3,294,935 bp distributed over two circular chromosomes of 2,117,144 bp and 1,177,787 bp encoding 3,197 ORFs. By using the bioinformatics suite ERGO, 2,487 (78%) ORFs were assigned functions. The origins of replication of the two chromosomes are similar to those of other α-proteobacteria. Housekeeping genes, including those involved in DNA replication, transcription, translation, core metabolism, and cell wall biosynthesis, are distributed on both chromosomes. Type I, II, and III secretion systems are absent, but genes encoding sec-dependent, sec-independent, and flagella-specific type III, type IV, and type V secretion systems as well as adhesins, invasins, and hemolysins were identified. Several features of the B. melitensis genome are similar to those of the symbiotic Sinorhizobium meliloti. PMID:11756688

Comparative proteome analysis of laboratory grown Brucella abortus 2308 and Brucella melitensis 16M.

PubMed

Eschenbrenner, Michel; Horn, Troy A; Wagner, Mary Ann; Mujer, Cesar V; Miller-Scandle, Tabbi L; DelVecchio, Vito G

2006-07-01

Brucella species are pathogenic agents that cause brucellosis, a debilitating zoonotic disease that affects a large variety of domesticated animals and humans. Brucella melitensis and Brucella abortus are considered major health threats because of their highly infectious nature and worldwide occurrence. The availability of the annotated genomes for these two species has allowed a comparative proteomics study of laboratory grown B. melitensis 16M and B. abortus 2308 by two-dimensional (2-D) gel electrophoresis and peptide mass fingerprinting. Computer-assisted analysis of the different 2-D gel images of strains 16M and 2308 revealed significant quantitative and qualitative differences in their protein expression patterns. Proteins involved in membrane transport, particularly the high affinity amino acids binding proteins, and those involved in Sec-dependent secretion systems related to type IV and type V secretion systems, were differentially expressed. Differential expression of these proteins may be responsible for conferring specific host preference in the two strains 2308 and 16M.

Anti-atherogenic activity of wild grape (Vitis thunbergii) extract antagonizing smooth muscle cell proliferation and migration promoted by neighboring macrophages.

PubMed

Kang, Sang-Wook; Kim, Min Soo; Kim, Hyun-Sung; Lee, Yong-Jin; Kang, Young-Hee

2012-06-01

The proliferation and migration of vascular smooth muscle cells (SMCs) play critical roles in intimal thickening and neointimal hyperplasia in early-phase atherosclerosis. This study tested whether wild grape extract (WGE) suppressed the proliferation and migration of human aortic SMCs induced by neighboring macrophages. Cellular expression of fibrogenic connective tissue growth factor (CTGF) and secretion of collagen IV and matrix metalloproteinase (MMP)-2 were determined in SMCs exposed to THP-1-differentiated macrophage-conditioned media. Proliferation was enhanced in SMCs exposed to macrophage-conditioned media collected during the early stage of differentiation, which was attenuated by treatment with ≥ 10 µg/ml WGE. Increased secretion of CTGF and collagen IV macrophage-conditioned media was suppressed in WGE-supplemented SMCs. TGF-β1-promoted production of CTGF and collagen IV was suppressed by blocking TGF-β receptors of R1 and R2 in SMCs. WGE repressed macrophage-conditioned media-upregulated MMP-2 secretion, indicating that WGE had an ability to encumber plaque rupture within atherosclerotic lesions. In addition, ≥ 1 µg/ml WGE ameliorated the migration of SMCs promoted by neighboring macrophages. These results demonstrate that WGE retarded neointimal hyperplasia and thickening within atherosclerotic plaques largely comprising of macrophages and SMCs. Therefore, WGE may be developed as an anti-proliferative and anti-migratory agent targeting SMCs in the proximity of newly differentiated and resident macrophages.

Differential Effects of Oral and Intravenous Lipid Administration on Key Molecules Related to Energy Homeostasis

PubMed Central

Vamvini, Maria T.; Hamnvik, Ole-Petter; Sahin-Efe, Ayse; Gavrieli, Anna; Dincer, Fadime; Farr, Olivia M.

2016-01-01

Context: The spectrum of lipid-induced changes in the secretion of hormones important in energy homeostasis has not yet been fully elucidated. Objective: To identify potential incretin-like effects in response to lipid administration, we examined the short-term effect of iv vs oral lipids on key molecules regulating energy homeostasis. Design, Intervention, and Participants: After a 10-hour overnight fast, 26 subjects were randomized to receive an oral lipid load, a 10% iv lipid emulsion, a 20% iv lipid emulsion, or an iv saline infusion. We obtained blood samples at 30-minute intervals for the first 2 hours and hourly thereafter for a total of 6 hours. Main Outcome Measures: Circulating levels of insulin, glucose, c-peptide, free fatty acids, incretins (glucagon-like peptide-1, gastric inhibitory polypeptide), glucagon, peptide YY, ghrelin, fibroblast growth factor 21, fetuin A, irisin, omentin, and adiponectin were measured. Results: Oral lipid ingestion resulted in higher glucagon-like peptide-1, gastric inhibitory polypeptide, glucagon, and peptide YY levels, compared with the other three groups (incremental area under the curve P = .003, P < .001, P < .001, P < .001, respectively). The 20% lipid emulsion, leading to higher free fatty acid levels, resulted in greater insulin, c-peptide, and fibroblast growth factor 21 responses compared with placebo and the other two groups (incremental area under the curve P = .002, P = .005, P < .001, P < .001, respectively). Omentin, adiponectin, fetuin A, and irisin levels were not affected by either mode of lipid administration. Conclusions: Metabolic responses to lipids depend on the route of administration. Only iv lipids trigger a dose-dependent fibroblast growth factor 21 secretion, which is nonglucagon mediated. Intravenous lipids also induce hyperinsulinemia without concurrent decreases in glucose, a phenomenon observed in insulin-resistant states. Orally administered lipids mostly affect gastrointestinal tract-secreted molecules important in glucose and energy homeostasis such as glucagon, incretins, and peptide YY. PMID:26964729

Pseudomonas aeruginosa Pore-Forming Exolysin and Type IV Pili Cooperate To Induce Host Cell Lysis

PubMed Central

Basso, Pauline; Ragno, Michel; Elsen, Sylvie; Reboud, Emeline; Golovkine, Guillaume; Bouillot, Stephanie; Huber, Philippe; Lory, Stephen; Faudry, Eric

2017-01-01

ABSTRACT   Clinical strains of Pseudomonas aeruginosa lacking the type III secretion system genes employ a toxin, exolysin (ExlA), for host cell membrane disruption. Here, we demonstrated that ExlA export requires a predicted outer membrane protein, ExlB, showing that ExlA and ExlB define a new active two-partner secretion (TPS) system of P. aeruginosa. In addition to the TPS signals, ExlA harbors several distinct domains, which include one hemagglutinin domain, five arginine-glycine-aspartic acid (RGD) motifs, and a C-terminal region lacking any identifiable sequence motifs. However, this C-terminal region is important for the toxic activity, since its deletion abolishes host cell lysis. Using lipid vesicles and eukaryotic cells, including red blood cells, we demonstrated that ExlA has a pore-forming activity which precedes cell membrane disruption of nucleated cells. Finally, we developed a high-throughput cell-based live-dead assay and used it to screen a transposon mutant library of an ExlA-producing P. aeruginosa clinical strain for bacterial factors required for ExlA-mediated toxicity. The screen resulted in the identification of proteins involved in the formation of type IV pili as being required for ExlA to exert its cytotoxic activity by promoting close contact between bacteria and the host cell. These findings represent the first example of cooperation between a pore-forming toxin of the TPS family and surface appendages in host cell intoxication. PMID:28119472

A Two-Year Randomized Trial of Interventions to Decrease Stress Hormone Vasopressin Production in Patients with Meniere's Disease-A Pilot Study.

PubMed

Kitahara, Tadashi; Okamoto, Hidehiko; Fukushima, Munehisa; Sakagami, Masaharu; Ito, Taeko; Yamashita, Akinori; Ota, Ichiro; Yamanaka, Toshiaki

2016-01-01

Meniere's disease, a common inner ear condition, has an incidence of 15-50 per 100,000. Because mental/physical stress and subsequent increase in the stress hormone vasopressin supposedly trigger Meniere's disease, we set a pilot study to seek new therapeutic interventions, namely management of vasopressin secretion, to treat this disease. We enrolled 297 definite Meniere's patients from 2010 to 2012 in a randomized-controlled and open-label trial, assigning Group-I (control) traditional oral medication, Group-II abundant water intake, Group-III tympanic ventilation tubes and Group-IV sleeping in darkness. Two hundred sixty-three patients completed the planned 2-year-follow-up, which included assessment of vertigo, hearing, plasma vasopressin concentrations and changes in stress/psychological factors. At 2 years, vertigo was completely controlled in 54.3% of patients in Group-I, 81.4% in Group-II, 84.1% in Group-III, and 80.0% in Group-IV (statistically I < II = III = IV). Hearing was improved in 7.1% of patients in Group-I, 35.7% in Group-II, 34.9% in Group-III, and 31.7% in Group-IV (statistically I < II = III = IV). Plasma vasopressin concentrations decreased more in Groups-II, -III, and -IV than in Groups-I (statistically I < II = III = IV), although patients' stress/psychological factors had not changed. Physicians have focused on stress management for Meniere's disease. However, avoidance of stress is unrealistic for patients who live in demanding social environments. Our findings in this pilot study suggest that interventions to decrease vasopressin secretion by abundant water intake, tympanic ventilation tubes and sleeping in darkness is feasible in treating Meniere's disease, even though these therapies did not alter reported mental/physical stress levels. ClinicalTrials.gov NCT01099046.

Identification of legionella effectors using bioinformatic approaches.

PubMed

Segal, Gil

2013-01-01

Legionella pneumophila the causative agent of Legionnaires' disease, actively manipulates host cell processes to establish a replication niche inside host cells. The establishment of its replication niche requires a functional Icm/Dot type IV secretion system which translocates about 300 effector proteins into host cells during infection. Many of these effectors were first identified as effector candidates by several bioinformatic approaches, and these predicted effectors were later examined experimentally for translocation and a large number of which were validated as effector proteins. Here, I summarized the bioinformatic approaches that were used to identify these effectors.

The Legionella pneumophila global regulatory protein LetA affects DotA and Mip.

PubMed

Shi, Chunwei; Forsbach-Birk, Vera; Marre, Reinhard; McNealy, Tamara L

2006-02-01

Several genes have been identified in Legionella pneumophila which are necessary for its virulence properties. These genes include the dot/icm type IV secretion system (T4SS), mip and letA. Genes of the dot/icm system, in particular dotA, have been found to be essential for intracellular growth. The macrophage infectivity protein (Mip) is also necessary for full virulence of the bacteria. Although these genes are well characterized, the regulation of such virulence factors is not. The LetA transcriptional activator interacts with the global regulator CsrA in controlling the switch from the replicative, non-infectious to the transmissive, highly infectious form of L. pneumophila. Regulation by LetA of the dot/icm genes has also been previously postulated. Here we show that the letA mutation exerts effects not only on DotA but on a substrate of the secretion system, RalF as well. LetA was found to be necessary for full transcriptional expression of the dotA and ralF genes. Although at the transcriptional level dotA was reduced, this did not result in a decrease of DotA protein in whole cell lysates. The letA mutation, however, does result in decreased amounts of the DotA protein found in the membrane and increased amounts in the culture supernatant. Additionally, the letA mutation dramatically decreased the secretion of Mip. This work demonstrates the participation of the global regulatory protein LetA in the regulation of an essential part of the dot/icm T4SS. Also shown is the presence of secreted Mip and a decrease in this secretion in the letA(-) strain. Exactly how LetA is regulating these virulence factors remains to be elucidated but it obviously occurs at both transcriptional and post-transcriptional levels.

Effect of atropine and somatostatin on bombesin-stimulated plasma immunoreactive trypsin release in man.

PubMed

de Jong, A J; Klamer, M; Lamers, C B

1987-01-01

This study was undertaken to determine the effect of atropine and somatostatin, two inhibitors of intraduodenal pancreatic enzyme secretion, on bombesin-stimulated release of plasma immunoreactive trypsin in 6 healthy volunteers. Infusion of 5 ng/kg.min bombesin during 30 min induced significant increases in plasma trypsin from 206 +/- 20 to 334 +/- 44 ng/ml (p less than 0.01). Atropine (15 ng/kg as i.v. bolus followed by 5 ng/kg.h) had no influence on the bombesin-stimulated increase in plasma immunoreactive trypsin (207 +/- 20 to 326 +/- 54 ng/ml). Somatostatin (125 micrograms as i.v. bolus followed by 125 micrograms/h) also failed to inhibit the plasma trypsin response to bombesin (207 +/- 18 to 663 +/- 166 ng/ml). These results point to major differences in the regulation of plasma and intraduodenal trypsin secretion.

[Infant botulism].

PubMed

Falk, Absalom; Afriat, Amichay; Hubary, Yechiel; Herzog, Lior; Eisenkraft, Arik

2014-01-01

Infant botulism is a paralytic syndrome which manifests as a result of ingesting spores of the toxin secreting bacterium Clostridium botulinum by infants. As opposed to botulism in adults, treating infant botulism with horse antiserum was not approved due to several safety issues. This restriction has led to the development of Human Botulism Immune Globulin Intravenous (BIG-IV; sells under BabyBIG). In this article we review infant botulism and the advantages of treating it with BIG-IV.

One-year metreleptin improves insulin secretion in patients with diabetes linked to genetic lipodystrophic syndromes.

PubMed

Vatier, C; Fetita, S; Boudou, P; Tchankou, C; Deville, L; Riveline, Jp; Young, J; Mathivon, L; Travert, F; Morin, D; Cahen, J; Lascols, O; Andreelli, F; Reznik, Y; Mongeois, E; Madelaine, I; Vantyghem, Mc; Gautier, Jf; Vigouroux, C

2016-07-01

Recombinant methionyl human leptin (metreleptin) therapy was shown to improve hyperglycaemia, dyslipidaemia and insulin sensitivity in patients with lipodystrophic syndromes, but its effects on insulin secretion remain controversial. We used dynamic intravenous (i.v.) clamp procedures to measure insulin secretion, adjusted to insulin sensitivity, at baseline and after 1 year of metreleptin therapy, in 16 consecutive patients with lipodystrophy, diabetes and leptin deficiency. Patients, with a mean [± standard error of the mean (s.e.m.)] age of 39.2 (±4) years, presented with familial partial lipodystrophy (n = 11, 10 women) or congenital generalized lipodystrophy (n = 5, four women). Their mean (± s.e.m.) BMI (23.9 ± 0.7 kg/m(2) ), glycated haemoglobin levels (8.5 ± 0.4%) and serum triglycerides levels (4.6 ± 0.9 mmol/l) significantly decreased within 1 month of metreleptin therapy, then remained stable. Insulin sensitivity (from hyperglycaemic or euglycaemic-hyperinsulinaemic clamps, n = 4 and n = 12, respectively), insulin secretion during graded glucose infusion (n = 12), and acute insulin response to i.v. glucose adjusted to insulin sensitivity (disposition index, n = 12), significantly increased after 1 year of metreleptin therapy. The increase in disposition index was related to a decrease in percentage of total and trunk body fat. Metreleptin therapy improves not only insulin sensitivity, but also insulin secretion in patients with diabetes attributable to genetic lipodystrophies. © 2015 John Wiley & Sons Ltd.

Peptide Nucleic Acid Knockdown and Intra-host Cell Complementation of Ehrlichia Type IV Secretion System Effector.

PubMed

Sharma, Pratibha; Teymournejad, Omid; Rikihisa, Yasuko

2017-01-01

Survival of Ehrlichia chaffeensis depends on obligatory intracellular infection. One of the barriers to E. chaffeensis research progress has been the inability, using conventional techniques, to generate knock-out mutants for genes essential for intracellular infection. This study examined the use of Peptide Nucleic Acids (PNAs) technology to interrupt type IV secretion system (T4SS) effector protein expression in E. chaffeensis followed by intracellular complementation of the effector to determine its requirement for infection. Successful E. chaffeensis infection depends on the E. chaffeensis -specific T4SS protein effector, ehrlichial translocated factor-1 (Etf-1), which induces Rab5-regulated autophagy to provide host cytosolic nutrients required for E. chaffeensis proliferation. Etf-1 is also imported by host cell mitochondria where it inhibits host cell apoptosis to prolong its infection. We designed a PNA specific to Etf-1 and showed that the PNA bound to the target region of single-stranded Etf-1 RNA using a competitive binding assay. Electroporation of E. chaffeensis with this PNA significantly reduced Etf-1 mRNA and protein, and the bacteria's ability to induce host cell autophagy and infect host cells. Etf-1 PNA-mediated inhibition of ehrlichial Etf-1 expression and E. chaffeensis infection could be intracellularly trans-complemented by ectopic expression of Etf-1-GFP in host cells. These data affirmed the critical role of bacterial T4SS effector in host cell autophagy and E. chaffeensis infection, and demonstrated the use of PNA to analyze the gene functions of obligate intracellular bacteria.

Peptide Nucleic Acid Knockdown and Intra-host Cell Complementation of Ehrlichia Type IV Secretion System Effector

PubMed Central

Sharma, Pratibha; Teymournejad, Omid; Rikihisa, Yasuko

2017-01-01

Survival of Ehrlichia chaffeensis depends on obligatory intracellular infection. One of the barriers to E. chaffeensis research progress has been the inability, using conventional techniques, to generate knock-out mutants for genes essential for intracellular infection. This study examined the use of Peptide Nucleic Acids (PNAs) technology to interrupt type IV secretion system (T4SS) effector protein expression in E. chaffeensis followed by intracellular complementation of the effector to determine its requirement for infection. Successful E. chaffeensis infection depends on the E. chaffeensis-specific T4SS protein effector, ehrlichial translocated factor-1 (Etf-1), which induces Rab5-regulated autophagy to provide host cytosolic nutrients required for E. chaffeensis proliferation. Etf-1 is also imported by host cell mitochondria where it inhibits host cell apoptosis to prolong its infection. We designed a PNA specific to Etf-1 and showed that the PNA bound to the target region of single-stranded Etf-1 RNA using a competitive binding assay. Electroporation of E. chaffeensis with this PNA significantly reduced Etf-1 mRNA and protein, and the bacteria's ability to induce host cell autophagy and infect host cells. Etf-1 PNA-mediated inhibition of ehrlichial Etf-1 expression and E. chaffeensis infection could be intracellularly trans-complemented by ectopic expression of Etf-1-GFP in host cells. These data affirmed the critical role of bacterial T4SS effector in host cell autophagy and E. chaffeensis infection, and demonstrated the use of PNA to analyze the gene functions of obligate intracellular bacteria. PMID:28638803

Simultaneous measurements of gastric motility and acid-bicarbonate secretions in the anaesthetized cat.

PubMed

Fändriks, L; Stage, L

1986-12-01

Chloralosed cats were acutely vagotomized, their splanchnic nerves cut and the adrenal glands ligated. The gastric lumen was perfused with isotonic NaCl and gastric motility was monitored as changes in hydrostatic pressure within the perfusion circuit. Gastric secretion of H+ and HCO3- were calculated from continuous measurements of pH and PCO2. Methodological tests ex vivo showed good accuracy of the estimations. Recovery of H+ after HCl instillation into the stomach in vivo was almost complete, while HCO3- recovery after NaHCO3 instillations was 85-95%. Pentagastrin (10 micrograms kg-1 h-1 i.v.) stimulated gastric contractile activity and increased gastric H+ secretion 30-fold, while HCO3- secretion decreased somewhat. Carbachol (4 micrograms kg-1 h-1) induced gastric contractions and increased H+ secretion by 400% and HCO3- output by 100-130%. Electrical stimulation of the cut vagal nerves (10 Hz for 10 min) induced well known gastric motor responses and increased gastric H+ secretion 20-fold preceded by a transient doubling of HCO3- secretion. Omeprazole, a selective inhibitor of gastric H+ secretion, decreased the vagally induced H+ secretion, while recorded gastric HCO3- secretion was clearly enhanced. In conclusion, the technique permits simultaneous recordings of rapid alterations of gastric motility and H+ and HCO3- secretions. However, HCO3- secretion was modestly underestimated, probably due to mucosal CO2 absorption.

Structural Insight into How Bacteria Prevent Interference between Multiple Divergent Type IV Secretion Systems

PubMed Central

Phan, Isabelle Q. H.; Scheib, Holger; Subramanian, Sandhya; Edwards, Thomas E.; Lehman, Stephanie S.; Piitulainen, Hanna; Sayeedur Rahman, M.; Rennoll-Bankert, Kristen E.; Staker, Bart L.; Taira, Suvi; Stacy, Robin; Myler, Peter J.; Azad, Abdu F.

2015-01-01

ABSTRACT Prokaryotes use type IV secretion systems (T4SSs) to translocate substrates (e.g., nucleoprotein, DNA, and protein) and/or elaborate surface structures (i.e., pili or adhesins). Bacterial genomes may encode multiple T4SSs, e.g., there are three functionally divergent T4SSs in some Bartonella species (vir, vbh, and trw). In a unique case, most rickettsial species encode a T4SS (rvh) enriched with gene duplication. Within single genomes, the evolutionary and functional implications of cross-system interchangeability of analogous T4SS protein components remains poorly understood. To lend insight into cross-system interchangeability, we analyzed the VirB8 family of T4SS channel proteins. Crystal structures of three VirB8 and two TrwG Bartonella proteins revealed highly conserved C-terminal periplasmic domain folds and dimerization interfaces, despite tremendous sequence divergence. This implies remarkable structural constraints for VirB8 components in the assembly of a functional T4SS. VirB8/TrwG heterodimers, determined via bacterial two-hybrid assays and molecular modeling, indicate that differential expression of trw and vir systems is the likely barrier to VirB8-TrwG interchangeability. We also determined the crystal structure of Rickettsia typhi RvhB8-II and modeled its coexpressed divergent paralog RvhB8-I. Remarkably, while RvhB8-I dimerizes and is structurally similar to other VirB8 proteins, the RvhB8-II dimer interface deviates substantially from other VirB8 structures, potentially preventing RvhB8-I/RvhB8-II heterodimerization. For the rvh T4SS, the evolution of divergent VirB8 paralogs implies a functional diversification that is unknown in other T4SSs. Collectively, our data identify two different constraints (spatiotemporal for Bartonella trw and vir T4SSs and structural for rvh T4SSs) that mediate the functionality of multiple divergent T4SSs within a single bacterium. PMID:26646013

Structural studies of a bifunctional inhibitor of neprilysin and DPP-IV.

PubMed

Oefner, Christian; Pierau, Sabine; Schulz, Henk; Dale, Glenn E

2007-09-01

Neutral endopeptidase (NEP) is the major enzyme involved in the metabolic inactivation of a number of bioactive peptides including the enkephalins, substance P, endothelin, bradykinin and atrial natriuretic factor, as well as the incretin hormone glucagon-like peptide 1 (GLP-1), which is a potent stimulator of insulin secretion. The activity of GLP-1 is also rapidly abolished by the serine protease dipeptidyl peptidase IV (DPP-IV), which led to an elevated interest in inhibitors of this enzyme for the treatment of type II diabetes. A dual NEP/DPP-IV inhibitor concept is proposed, offering an alternative strategy for the treatment of type 2 diabetes. Here, the synthesis and crystal structures of the soluble extracellular domain of human NEP (residues 52-749) complexed with the NEP, competitive and potent dual NEP/DPP-IV inhibitor MCB3937 are described.

The effect of adrenaline and noradrenaline on hormone secretion and blood flow from the thyroid vein in sheep with exteriorized thyroids.

PubMed

Falconer, I R

1967-02-01

1. Emotional stimulus to the sheep has previously been shown to cause increased thyroid hormone secretion; the influence of adrenaline and noradrenaline in this process has been investigated.2. Sheep bearing exteriorized thyroid glands on carotid artery-jugular vein loops were used. Thyroid vein blood was collected through a cannula in the jugular vein within the loop, and blood flow was measured by a plethysmographic technique.3. (131)I (50 muc) was injected intramuscularly (I.M.) into the sheep, and 4-7 days later the concentration of total and protein bound (131)I in thyroid vein blood was measured in samples taken every 10 min for 4 hr. Intracarotid injections of 1 mug, I.V. injections of 5 mug, or I.V. infusions at 10 mug/min for 10 min, of adrenaline or noradrenaline were administered 1.5 hr after commencement of sampling. Blood flow from the thyroid was measured in similar experiments.4. No significant changes in thyroid hormone secretion could be attributed to adrenaline or noradrenaline, and it was concluded that circulating catecholamines do not influence the release of thyroid hormone observed after brief emotional stimulus in the sheep.

Mice deficient for the secreted glycoprotein SPARC/osteonectin/BM40 develop normally but show severe age-onset cataract formation and disruption of the lens.

PubMed Central

Gilmour, D T; Lyon, G J; Carlton, M B; Sanes, J R; Cunningham, J M; Anderson, J R; Hogan, B L; Evans, M J; Colledge, W H

1998-01-01

SPARC (secreted protein acidic and rich in cysteine, also known as osteonectin/BM40) is a secreted Ca2+-binding glycoprotein that interacts with a range of extracellular matrix molecules, including collagen IV. It is widely expressed during embryogenesis, and in vitro studies have suggested roles in the regulation of cell adhesion and proliferation, and in the modulation of cytokine activity. In order to analyse the function of this protein in vivo, the endogenous Sparc locus was disrupted by homologous recombination in murine embryonic stem cells. SPARC-deficient mice (Sparctm1Cam) appear normal and fertile until around 6 months of age, when they develop severe eye pathology characterized by cataract formation and rupture of the lens capsule. The first sign of lens pathology occurs in the equatorial bow region where vacuoles gradually form within differentiating epithelial cells and fibre cells. The lens capsule, however, shows no qualitative changes in the major basal lamina proteins laminin, collagen IV, perlecan or entactin. These mice are an excellent resource for further studies on how SPARC affects cell behaviour in vivo. PMID:9524110

A Split-Luciferase-Based Trimer Formation Assay as a High-throughput Screening Platform for Therapeutics in Alport Syndrome.

PubMed

Omachi, Kohei; Kamura, Misato; Teramoto, Keisuke; Kojima, Haruka; Yokota, Tsubasa; Kaseda, Shota; Kuwazuru, Jun; Fukuda, Ryosuke; Koyama, Kosuke; Matsuyama, Shingo; Motomura, Keishi; Shuto, Tsuyoshi; Suico, Mary Ann; Kai, Hirofumi

2018-05-17

Alport syndrome is a hereditary glomerular disease caused by mutation in type IV collagen α3-α5 chains (α3-α5(IV)), which disrupts trimerization, leading to glomerular basement membrane degeneration. Correcting the trimerization of α3/α4/α5 chain is a feasible therapeutic approach, but is hindered by lack of information on the regulation of intracellular α(IV) chain and the absence of high-throughput screening (HTS) platforms to assess α345(IV) trimer formation. Here, we developed sets of split NanoLuc-fusion α345(IV) proteins to monitor α345(IV) trimerization of wild-type and clinically associated mutant α5(IV). The α345(IV) trimer assay, which satisfied the acceptance criteria for HTS, enabled the characterization of intracellular- and secretion-dependent defects of mutant α5(IV). Small interfering RNA-based and chemical screening targeting the ER identified several chemical chaperones that have potential to promote α345(IV) trimer formation. This split luciferase-based trimer formation assay is a functional HTS platform that realizes the feasibility of targeting α345(IV) trimers to treat Alport syndrome. Copyright © 2018 Elsevier Ltd. All rights reserved.

A Novel Mechanism for Protein Delivery by the Type 3 Secretion System for Extracellularly Secreted Proteins.

PubMed

Tejeda-Dominguez, Farid; Huerta-Cantillo, Jazmin; Chavez-Dueñas, Lucia; Navarro-Garcia, Fernando

2017-03-28

The type 3 secretion system (T3SS) is essential for bacterial virulence through delivering effector proteins directly into the host cytosol. Here, we identified an alternative delivery mechanism of virulence factors mediated by the T3SS, which consists of the association of extracellularly secreted proteins from bacteria with the T3SS to gain access to the host cytosol. Both EspC, a protein secreted as an enteropathogenic Escherichia coli (EPEC) autotransporter, and YopH, a protein detected on the surface of Yersinia , require a functional T3SS for host cell internalization; here we provide biophysical and molecular evidence to support the concept of the EspC translocation mechanism, which requires (i) an interaction between EspA and an EspC middle segment, (ii) an EspC translocation motif (21 residues that are shared with the YopH translocation motif), (iii) increases in the association and dissociation rates of EspC mediated by EspA interacting with EspD, and (iv) an interaction of EspC with the EspD/EspB translocon pore. Interestingly, this novel mechanism does not exclude the injection model (i.e., EspF) operating through the T3SS conduit; therefore, T3SS can be functioning as an internal conduit or as an external railway, which can be used to reach the translocator pore, and this mechanism appears to be conserved among different T3SS-dependent pathogens. IMPORTANCE The type 3 secretion system is essential for injection of virulence factors, which are delivered directly into the cytosol of the host cells for usurping and subverting host processes. Recent studies have shown that these effectors proteins indeed travel inside an "injectisome" conduit through a single step of translocation by connecting the bacterium and host cell cytoplasms. However, all findings are not compatible with this model. For example, both YopH, a protein detected on the surface of Yersinia , and EspC, an autotransporter protein secreted by enteropathogenic E. coli , require a functional T3SS for host cell translocation. Both proteins have an intermediate extracellular step before their T3SS-dependent translocation. Here, we show an alternative delivery mechanism for these extracellularly secreted virulence factors that are then incorporated into the T3SS to enter the cells; this novel mechanism coexists with but diverges from the canonical injection model that involves the passage of the protein inside the injectisome. Copyright © 2017 Tejeda-Dominguez et al.

Clinical experience with pantoprazole in gastroesophageal reflux disease.

PubMed

Avner, D L

2000-10-01

Pantoprazole is a new proton pump inhibitor indicated for the treatment of erosive esophagitis associated with gastroesophageal reflux disease (GERD) and is available in both oral and intravenous (IV) formulations. This paper reviews the pharmacologic properties of pantoprazole and summarizes the findings from clinical studies of this drug. This review was compiled from the published literature, abstracts from clinical trials, and data on file with the manufacturer of pantoprazole. Pantoprazole selectively accumulates in the acidic environment of gastric parietal cells and acts at the final step of acid secretion by binding 2 key cysteine residues of the proton pump involved in gastric acid production. The bioavailability of pantoprazole is not altered by concomitant administration of food or antacids or with repeated dosing. Both oral and IV formulations of pantoprazole exhibit linear pharmacokinetics. Several clinical trials have proved pantoprazole superior to histamine-2-receptor antagonists (H2RAs) in reducing acid secretion and elevating gastric pH levels. Pantoprazole has been shown to be more effective than ranitidine (P < 0.05), famotidine (P < 0.001), and nizatidine (P < 0.05), and at least as effective as omeprazole, in healing erosive esophagitis and relieving associated symptoms of GERD, including regurgitation. Pantoprazole is also more effective than the H2RA nizatidine for the treatment of nighttime heartburn (P < 0.05). Studies have shown pantoprazole to be well tolerated; adverse events, including headache, diarrhea, flatulence, abdominal pain, eructation, nausea, and rash, occurred in < or = 6% of patients. The oral and IV formulations of pantoprazole are equally potent in inhibiting gastric acid secretion; thus, switching between formulations requires no dosage adjustments. Special patient populations, including the elderly and patients with renal or mild to moderate hepatic impairment, can take pantoprazole without an adjustment in dosage. Because of its unique pharmacokinetic properties, mechanism of action, and reduced potential for producing cytochrome P-450-based drug interactions, pantoprazole in both oral and IV formulations is effective over a full 24 hours and is well tolerated in a variety of patient types.

Combination of Peptide YY3–36 with GLP-17–36 amide Causes an Increase in First-Phase Insulin Secretion after IV Glucose

PubMed Central

Tan, Tricia M.; Salem, Victoria; Troke, Rachel C.; Alsafi, Ali; Field, Benjamin C. T.; De Silva, Akila; Misra, Shivani; Baynes, Kevin C. R.; Donaldson, Mandy; Minnion, James; Ghatei, Mohammad A.; Godsland, Ian F.

2014-01-01

Context: The combination of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) has been proposed as a potential treatment for diabetes and obesity. However, the combined effects of these hormones, PYY3–36 and GLP-17–36 amide, on glucose homeostasis are unknown. Objective: This study sought to investigate the acute effects of PYY3–36 and GLP-17–36 amide, individually and in combination, on insulin secretion and sensitivity. Setting and Design: Using a frequently sampled iv glucose tolerance test (FSIVGTT) and minimal modeling, this study measured the effects of PYY3–36 alone, GLP-17–36 amide alone, and a combination of PYY3–36 and GLP-17–36 amide on acute insulin response to glucose (AIRg) and insulin sensitivity index (SI) in 14 overweight human volunteers, studied in a clinical research facility. Results: PYY3–36 alone caused a small but nonsignificant increase in AIRg. GLP-17–36 amide alone and the combination of PYY3–36 and GLP-17–36 amide did increase AIRg significantly. No significant differences in SI were observed with any intervention. Conclusions: PYY3–36 lacks any significant acute effects on first-phase insulin secretion or SI when tested using an FSIVGTT. Both GLP-17–36 amide alone and the combination of PYY3–36 and GLP-17–36 amide increase first-phase insulin secretion. There does not seem to be any additive or synergistic effect between PYY3–36 and GLP-17–36 amide on first-phase insulin secretion. Neither hormone alone nor the combination had any significant effects on SI. PMID:25144632

The BatR/BatS Two-Component Regulatory System Controls the Adaptive Response of Bartonella henselae during Human Endothelial Cell Infection ▿ † ‡

PubMed Central

Quebatte, Maxime; Dehio, Michaela; Tropel, David; Basler, Andrea; Toller, Isabella; Raddatz, Guenter; Engel, Philipp; Huser, Sonja; Schein, Hermine; Lindroos, Hillevi L.; Andersson, Siv G. E.; Dehio, Christoph

2010-01-01

Here, we report the first comprehensive study of Bartonella henselae gene expression during infection of human endothelial cells. Expression of the main cluster of upregulated genes, comprising the VirB type IV secretion system and its secreted protein substrates, is shown to be under the positive control of the transcriptional regulator BatR. We demonstrate binding of BatR to the promoters of the virB operon and a substrate-encoding gene and provide biochemical evidence that BatR and BatS constitute a functional two-component regulatory system. Moreover, in contrast to the acid-inducible (pH 5.5) homologs ChvG/ChvI of Agrobacterium tumefaciens, BatR/BatS are optimally activated at the physiological pH of blood (pH 7.4). By conservation analysis of the BatR regulon, we show that BatR/BatS are uniquely adapted to upregulate a genus-specific virulence regulon during hemotropic infection in mammals. Thus, we propose that BatR/BatS two-component system homologs represent vertically inherited pH sensors that control the expression of horizontally transmitted gene sets critical for the diverse host-associated life styles of the alphaproteobacteria. PMID:20418395

Effect of long-term administration of dietary fiber on the exocrine pancreas in the rat.

PubMed

Sommer, H; Kasper, H

1984-08-01

Male Sprague-Dawley rats (50--70g) were fed a standard laboratory diet containing 6% dietary fiber substances (diet I), the same diet supplemented with 5% guar (diet II), 10% wheat bran (diet III), or 5% pectin of high (76%) methylic esterification (diet IV), or a fiber-free diet (diet V). After a 6-week feeding period, the body weight of the animals had increased to 300--350g. The common bile duct was then canulated and the exocrine pancreatic function tested under urethane anesthesia (1.5 g/kg body weight). The tested fiber substances had no effect on the basal pancreatic secretion of volume, bicarbonate, lipase, amylase or protein, or on the wet weight and histological appearance of the organ. However, the fiber substances influenced the pancreatic response to maximal exogenous stimulation with secretin (3.0 CU/100 g X hour) and cholecystokinin (0.6 IDU/100 g X hour) and the enzyme content of the gland significantly. Compared with diet V, diet I increased the DNA content of the pancreas and its secretion of bicarbonate and protein, and decreased the protein concentration in the gland. Diet II reduced the pancreatic content of trypsinogen and protein. Diet III decreased the protein content, but increased the bicarbonate secretion, which was also increased by diet IV. -- We conclude that fiber substances influence stimulated secretion and the enzyme content of the pancrease to a varying degree.

Virulence Effects and Signaling Partners Modulated by Brucella melitensis Light-sensing Histidine Kinase

NASA Astrophysics Data System (ADS)

Gourley, Christopher R.

The facultative intracellular pathogen Brucella melitensis utilizes diverse virulence factors. A Brucella light sensing histidine kinase can influence in vitro virulence of the bacteria during intracellular infection. First, we demonstrated that the B. melitensis light sensing kinase (BM-LOV-HK) affects virulence in an IRF-1-/- mouse model of infection. Infection with a Δ BM-LOV-HK strain resulted in less bacterial colonization of IRF-1-/- spleens and extended survivorship compared to mice infected with wild type B. melitensis 16M. Second, using PCR arrays, we observed less expression of innate and adaptive immune system activation markers in ΔBM-LOV-HK infected mouse spleens than wild type B. melitensis 16M infected mouse spleens 6 days after infection. Third, we demonstrated by microarray analysis of B. melitensis that deletion of BM-LOV-HK alters bacterial gene expression. Downregulation of genes involved in control of the general stress response system included the alternative sigma factor RpoE1 and its anti-anti sigma factor PhyR. Conversely, genes involved in flagella production, quorum sensing, and the type IV secretion system (VirB operon) were upregulated in the Δ BM-LOV-HK strain compared to the wild type B. melitensis 16M. Analysis of genes differentially regulated in Δ BM-LOV-HK versus the wild type strain indicated an overlap of 110 genes with data from previous quorum sensing regulator studies of Δ vjbR and/ΔblxR(babR) strains. Also, several predicted RpoE1 binding sites located upstream of genes were differentially regulated in the ΔBM-LOV-HK strain. Our results suggest BM-LOV-HK is important for in vivo Brucella virulence, and reveals that BM-LOV-HK directly or indirect regulates members of the Brucella quorum sensing, type IV secretion, and general stress systems.

Identification and characterization of a dipeptidyl peptidase IV inhibitor from aronia juice

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

Kozuka, Miyuki; Yamane, Takuya, E-mail: t-yamane@pharm.hokudai.ac.jp; Nakano, Yoshihisa

Aronia berries have many potential effects on health, including an antioxidant effect, effect for antimutagenesis, hepatoprotection and cardioprotection, an antidiabetic effect and inhibition of cancer cell proliferation. Previous human studies have shown that aronia juice may be useful for treatment of obesity disorders. In this study, we found that aronia juice has an inhibitory effect against dipeptidyl peptidase IV (DPP IV) (EC 3.4.14.5). DPP IV is a peptidase that cleaves the N-terminal region of incretins such as glucagon-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Inactivation of incretins by DPP IV induces reduction of insulin secretion. Furthermore, we identified thatmore » cyanidin 3, 5-diglucoside as the DPP IV inhibitor in aronia juice. DPP IV was inhibited more strongly by cyanidin 3, 5-diglucoside than by cyanidin and cyanidin 3-glucoside. The results suggest that DPP IV is inhibited by cyanidin 3, 5-diglucoside present in aronia juice. The antidiabetic effect of aronia juice may be mediated through DPP IV inhibition by cyanidin 3, 5-diglucoside. - Highlights: • DPP IV activity is inhibited by aronia juice. • DPP IV inhibitor is cyanidin 3, 5-diglucoside in aronia juice. • DPP IV is inhibited by cyanidin 3, 5-diglucoside more than cyanidin and cyanidin 3-glucoside.« less

Neuropeptide S reduces duodenal bicarbonate secretion and ethanol-induced increases in duodenal motility in rats

PubMed Central

Wan Saudi, Wan Salman

2017-01-01

Alcohol disrupts the intestinal mucosal barrier by inducing metabolic and functional changes in epithelial cells. Recently, we showed that neuropeptide S (NPS) decreases duodenal motility and increases mucosal paracellular permeability, suggesting a role of NPS in the pathogenesis of disorders and dysfunctions in the small intestine. The aim of the present study was to investigate the effects of NPS on ethanol- and HCl-induced changes of duodenal mucosal barrier function and motility. Rats were anaesthetized with thiobarbiturate, and a 30-mm segment of the proximal duodenum with an intact blood supply was perfused in situ. The effects on duodenal bicarbonate secretion, the blood-to-lumen clearance of 51Cr-EDTA, motility and transepithelial net fluid flux were investigated. Intravenous (i.v.) administration of NPS significantly reduced duodenal mucosal bicarbonate secretion and stimulated mucosal transepithelial fluid absorption, mechanisms dependent on nitrergic signaling. NPS dose-dependently reduced ethanol-induced increases in duodenal motility. NPS (83 pmol·kg-1·min-1, i.v.) reduced the bicarbonate and fluid secretory response to luminal ethanol, whereas a 10-fold higher dose stimulated fluid secretion but did not influence bicarbonate secretion. In NPS-treated animals, duodenal perfusion of acid (pH 3) induced greater bicarbonate secretory rates than in controls. Pre-treating animals with Nω-nitro-L-arginine methyl ester (L-NAME) inhibited the effect of NPS on bicarbonate secretion. In response to luminal acid, NPS-treated animals had significantly higher paracellular permeability compared to controls, an effect that was abolished by L-NAME. Our findings demonstrate that NPS reduces basal and ethanol-induced increases in duodenal motility. In addition, NPS increases luminal alkalinization and mucosal permeability in response to luminal acid via mechanisms that are dependent on nitric oxide signaling. The data support a role for NPS in neurohumoral regulation of duodenal mucosal barrier function and motility. PMID:28384243

The CpxRA two-component system contributes to Legionella pneumophila virulence.

PubMed

Tanner, Jennifer R; Li, Laam; Faucher, Sébastien P; Brassinga, Ann Karen C

2016-06-01

The bacterium Legionella pneumophila is capable of intracellular replication within freshwater protozoa as well as human macrophages, the latter of which results in the serious pneumonia Legionnaires' disease. A primary factor involved in these host cell interactions is the Dot/Icm Type IV secretion system responsible for translocating effector proteins needed to establish and maintain the bacterial replicative niche. Several regulatory factors have been identified to control the expression of the Dot/Icm system and effectors, one of which is the CpxRA two-component system, suggesting essentiality for virulence. In this study, we generated cpxR, cpxA and cpxRA in-frame null mutant strains to further delineate the role of the CpxRA system in bacterial survival and virulence. We found that cpxR is essential for intracellular replication within Acanthamoeba castellanii, but not in U937-derived macrophages. Transcriptome analysis revealed that CpxRA regulates a large number of virulence-associated proteins including Dot/Icm effectors as well as Type II secreted substrates. Furthermore, the cpxR and cpxRA mutant strains were more sodium resistant than the parental strain Lp02, and cpxRA expression reaches maximal levels during postexponential phase. Taken together, our findings suggest the CpxRA system is a key contributor to L. pneumophila virulence in protozoa via virulence factor regulation. © 2016 John Wiley & Sons Ltd.

Invisible Ink Marking in ECL Membrane Assays.

PubMed

Kurien, Biji T

2015-01-01

Invisible ink and writing secret messages have been part of man's fantasy, having proven useful in clandestine and high sensitivity areas. Security inks, made up of invisible materials that give printed, anti-photocopy images capable of being read only under special environments, have become important. An ink formulation based on silicon(IV) 2,3-naphthalocyanine bis(trihexylsilyloxide) as colorant, invisible to the naked eye but infrared readable, has been described earlier. Biometric DNA ink has also been developed for security authentication. In lighter vein, many budding scientists and others have often experimented with writing secret messages on paper, either for purposes of fun or actually sending secret messages to friends. It involved the use of lemon juice, milk, or other solutions that could be used with a dip pen, brush, or a fountain pen to write invisible messages on a blank white paper. Words turn up as magic when the paper is exposed to heat in one form or the other. Here, we attempt to end this book on a slightly humorous note by showing that invisible messages can be written on nitrocellulose membranes (but not on polyvinylidene difluoride membranes) using an appropriately diluted horse radish peroxidase/alkaline phosphatase anti-IgG conjugate (rabbit, mouse, or human anti-IgG). The message is written on the membrane, preferably with a fountain pen, and the membrane is allowed to dry. Regular detection with enhanced chemiluminescence plus or nitro blue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate systems is used to unravel the secret message. In addition, this method could be used to mark nitrocellulose membranes for orientation purposes using ECL detection system and thus can eliminate the use of autoradiography pens.

A Global Overview of the Genetic and Functional Diversity in the Helicobacter pylori cag Pathogenicity Island

PubMed Central

Moodley, Yoshan; Uhr, Markus; Stamer, Christiana; Vauterin, Marc; Suerbaum, Sebastian; Achtman, Mark

2010-01-01

The Helicobacter pylori cag pathogenicity island (cagPAI) encodes a type IV secretion system. Humans infected with cagPAI–carrying H. pylori are at increased risk for sequelae such as gastric cancer. Housekeeping genes in H. pylori show considerable genetic diversity; but the diversity of virulence factors such as the cagPAI, which transports the bacterial oncogene CagA into host cells, has not been systematically investigated. Here we compared the complete cagPAI sequences for 38 representative isolates from all known H. pylori biogeographic populations. Their gene content and gene order were highly conserved. The phylogeny of most cagPAI genes was similar to that of housekeeping genes, indicating that the cagPAI was probably acquired only once by H. pylori, and its genetic diversity reflects the isolation by distance that has shaped this bacterial species since modern humans migrated out of Africa. Most isolates induced IL-8 release in gastric epithelial cells, indicating that the function of the Cag secretion system has been conserved despite some genetic rearrangements. More than one third of cagPAI genes, in particular those encoding cell-surface exposed proteins, showed signatures of diversifying (Darwinian) selection at more than 5% of codons. Several unknown gene products predicted to be under Darwinian selection are also likely to be secreted proteins (e.g. HP0522, HP0535). One of these, HP0535, is predicted to code for either a new secreted candidate effector protein or a protein which interacts with CagA because it contains two genetic lineages, similar to cagA. Our study provides a resource that can guide future research on the biological roles and host interactions of cagPAI proteins, including several whose function is still unknown. PMID:20808891

A global overview of the genetic and functional diversity in the Helicobacter pylori cag pathogenicity island.

PubMed

Olbermann, Patrick; Josenhans, Christine; Moodley, Yoshan; Uhr, Markus; Stamer, Christiana; Vauterin, Marc; Suerbaum, Sebastian; Achtman, Mark; Linz, Bodo

2010-08-19

The Helicobacter pylori cag pathogenicity island (cagPAI) encodes a type IV secretion system. Humans infected with cagPAI-carrying H. pylori are at increased risk for sequelae such as gastric cancer. Housekeeping genes in H. pylori show considerable genetic diversity; but the diversity of virulence factors such as the cagPAI, which transports the bacterial oncogene CagA into host cells, has not been systematically investigated. Here we compared the complete cagPAI sequences for 38 representative isolates from all known H. pylori biogeographic populations. Their gene content and gene order were highly conserved. The phylogeny of most cagPAI genes was similar to that of housekeeping genes, indicating that the cagPAI was probably acquired only once by H. pylori, and its genetic diversity reflects the isolation by distance that has shaped this bacterial species since modern humans migrated out of Africa. Most isolates induced IL-8 release in gastric epithelial cells, indicating that the function of the Cag secretion system has been conserved despite some genetic rearrangements. More than one third of cagPAI genes, in particular those encoding cell-surface exposed proteins, showed signatures of diversifying (Darwinian) selection at more than 5% of codons. Several unknown gene products predicted to be under Darwinian selection are also likely to be secreted proteins (e.g. HP0522, HP0535). One of these, HP0535, is predicted to code for either a new secreted candidate effector protein or a protein which interacts with CagA because it contains two genetic lineages, similar to cagA. Our study provides a resource that can guide future research on the biological roles and host interactions of cagPAI proteins, including several whose function is still unknown.

The Trw Type IV Secretion System of Bartonella Mediates Host-Specific Adhesion to Erythrocytes

PubMed Central

Vayssier-Taussat, Muriel; Le Rhun, Danielle; Deng, Hong Kuan; Biville, Francis; Cescau, Sandra; Danchin, Antoine; Marignac, Geneviève; Lenaour, Evelyne; Boulouis, Henri Jean; Mavris, Maria; Arnaud, Lionel; Yang, Huanming; Wang, Jing; Quebatte, Maxime; Engel, Philipp; Saenz, Henri; Dehio, Christoph

2010-01-01

Bacterial pathogens typically infect only a limited range of hosts; however, the genetic mechanisms governing host-specificity are poorly understood. The α-proteobacterial genus Bartonella comprises 21 species that cause host-specific intraerythrocytic bacteremia as hallmark of infection in their respective mammalian reservoirs, including the human-specific pathogens Bartonella quintana and Bartonella bacilliformis that cause trench fever and Oroya fever, respectively. Here, we have identified bacterial factors that mediate host-specific erythrocyte colonization in the mammalian reservoirs. Using mouse-specific Bartonella birtlesii, human-specific Bartonella quintana, cat-specific Bartonella henselae and rat-specific Bartonella tribocorum, we established in vitro adhesion and invasion assays with isolated erythrocytes that fully reproduce the host-specificity of erythrocyte infection as observed in vivo. By signature-tagged mutagenesis of B. birtlesii and mutant selection in a mouse infection model we identified mutants impaired in establishing intraerythrocytic bacteremia. Among 45 abacteremic mutants, five failed to adhere to and invade mouse erythrocytes in vitro. The corresponding genes encode components of the type IV secretion system (T4SS) Trw, demonstrating that this virulence factor laterally acquired by the Bartonella lineage is directly involved in adherence to erythrocytes. Strikingly, ectopic expression of Trw of rat-specific B. tribocorum in cat-specific B. henselae or human-specific B. quintana expanded their host range for erythrocyte infection to rat, demonstrating that Trw mediates host-specific erythrocyte infection. A molecular evolutionary analysis of the trw locus further indicated that the variable, surface-located TrwL and TrwJ might represent the T4SS components that determine host-specificity of erythrocyte parasitism. In conclusion, we show that the laterally acquired Trw T4SS diversified in the Bartonella lineage to facilitate host-restricted adhesion to erythrocytes in a wide range of mammals. PMID:20548954

Evolutionary Dynamics of Pathoadaptation Revealed by Three Independent Acquisitions of the VirB/D4 Type IV Secretion System in Bartonella

PubMed Central

Harms, Alexander; Segers, Francisca H.I.D.; Quebatte, Maxime; Mistl, Claudia; Manfredi, Pablo; Körner, Jonas; Chomel, Bruno B.; Kosoy, Michael; Maruyama, Soichi; Engel, Philipp

2017-01-01

The α-proteobacterial genus Bartonella comprises a group of ubiquitous mammalian pathogens that are studied as a model for the evolution of bacterial pathogenesis. Vast abundance of two particular phylogenetic lineages of Bartonella had been linked to enhanced host adaptability enabled by lineage-specific acquisition of a VirB/D4 type IV secretion system (T4SS) and parallel evolution of complex effector repertoires. However, the limited availability of genome sequences from one of those lineages as well as other, remote branches of Bartonella has so far hampered comprehensive understanding of how the VirB/D4 T4SS and its effectors called Beps have shaped Bartonella evolution. Here, we report the discovery of a third repertoire of Beps associated with the VirB/D4 T4SS of B. ancashensis, a novel human pathogen that lacks any signs of host adaptability and is only distantly related to the two species-rich lineages encoding a VirB/D4 T4SS. Furthermore, sequencing of ten new Bartonella isolates from under-sampled lineages enabled combined in silico analyses and wet lab experiments that suggest several parallel layers of functional diversification during evolution of the three Bep repertoires from a single ancestral effector. Our analyses show that the Beps of B. ancashensis share many features with the two other repertoires, but may represent a more ancestral state that has not yet unleashed the adaptive potential of such an effector set. We anticipate that the effectors of B. ancashensis will enable future studies to dissect the evolutionary history of Bartonella effectors and help unraveling the evolutionary forces underlying bacterial host adaptation. PMID:28338931

Nicotinamide induces differentiation of embryonic stem cells into insulin-secreting cells

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

Vaca, Pilar; Berna, Genoveva; Araujo, Raquel

2008-03-10

The poly(ADP-ribose) polymerase (PARP) inhibitor, nicotinamide, induces differentiation and maturation of fetal pancreatic cells. In addition, we have previously reported evidence that nicotinamide increases the insulin content of cells differentiated from embryonic stem (ES) cells, but the possibility of nicotinamide acting as a differentiating agent on its own has never been completely explored. Islet cell differentiation was studied by: (i) X-gal staining after neomycin selection; (ii) BrdU studies; (iii) single and double immunohistochemistry for insulin, C-peptide and Glut-2; (iv) insulin and C-peptide content and secretion assays; and (v) transplantation of differentiated cells, under the kidney capsule, into streptozotocin (STZ)-diabetic mice.more » Here we show that undifferentiated mouse ES cells treated with nicotinamide: (i) showed an 80% decrease in cell proliferation; (ii) co-expressed insulin, C-peptide and Glut-2; (iii) had values of insulin and C-peptide corresponding to 10% of normal mouse islets; (iv) released insulin and C-peptide in response to stimulatory glucose concentrations; and (v) after transplantation into diabetic mice, normalized blood glucose levels over 7 weeks. Our data indicate that nicotinamide decreases ES cell proliferation and induces differentiation into insulin-secreting cells. Both aspects are very important when thinking about cell therapy for the treatment of diabetes based on ES cells.« less

Genome-scale identification of Legionella pneumophila effectors using a machine learning approach.

PubMed

Burstein, David; Zusman, Tal; Degtyar, Elena; Viner, Ram; Segal, Gil; Pupko, Tal

2009-07-01

A large number of highly pathogenic bacteria utilize secretion systems to translocate effector proteins into host cells. Using these effectors, the bacteria subvert host cell processes during infection. Legionella pneumophila translocates effectors via the Icm/Dot type-IV secretion system and to date, approximately 100 effectors have been identified by various experimental and computational techniques. Effector identification is a critical first step towards the understanding of the pathogenesis system in L. pneumophila as well as in other bacterial pathogens. Here, we formulate the task of effector identification as a classification problem: each L. pneumophila open reading frame (ORF) was classified as either effector or not. We computationally defined a set of features that best distinguish effectors from non-effectors. These features cover a wide range of characteristics including taxonomical dispersion, regulatory data, genomic organization, similarity to eukaryotic proteomes and more. Machine learning algorithms utilizing these features were then applied to classify all the ORFs within the L. pneumophila genome. Using this approach we were able to predict and experimentally validate 40 new effectors, reaching a success rate of above 90%. Increasing the number of validated effectors to around 140, we were able to gain novel insights into their characteristics. Effectors were found to have low G+C content, supporting the hypothesis that a large number of effectors originate via horizontal gene transfer, probably from their protozoan host. In addition, effectors were found to cluster in specific genomic regions. Finally, we were able to provide a novel description of the C-terminal translocation signal required for effector translocation by the Icm/Dot secretion system. To conclude, we have discovered 40 novel L. pneumophila effectors, predicted over a hundred additional highly probable effectors, and shown the applicability of machine learning algorithms for the identification and characterization of bacterial pathogenesis determinants.

Comparative analyses of Xanthomonas and Xylella complete genomes.

PubMed

Moreira, Leandro M; De Souza, Robson F; Digiampietri, Luciano A; Da Silva, Ana C R; Setubal, João C

2005-01-01

Computational analyses of four bacterial genomes of the Xanthomonadaceae family reveal new unique genes that may be involved in adaptation, pathogenicity, and host specificity. The Xanthomonas genus presents 3636 unique genes distributed in 1470 families, while Xylella genus presents 1026 unique genes distributed in 375 families. Among Xanthomonas-specific genes, we highlight a large number of cell wall degrading enzymes, proteases, and iron receptors, a set of energy metabolism genes, second copy of the type II secretion system, type III secretion system, flagella and chemotactic machinery, and the xanthomonadin synthesis gene cluster. Important genes unique to the Xylella genus are an additional copy of a type IV pili gene cluster and the complete machinery of colicin V synthesis and secretion. Intersections of gene sets from both genera reveal a cluster of genes homologous to Salmonella's SPI-7 island in Xanthomonas axonopodis pv citri and Xylella fastidiosa 9a5c, which might be involved in host specificity. Each genome also presents important unique genes, such as an HMS cluster, the kdgT gene, and O-antigen in Xanthomonas axonopodis pv citri; a number of avrBS genes and a distinct O-antigen in Xanthomonas campestris pv campestris, a type I restriction-modification system and a nickase gene in Xylella fastidiosa 9a5c, and a type II restriction-modification system and two genes related to peptidoglycan biosynthesis in Xylella fastidiosa temecula 1. All these differences imply a considerable number of gene gains and losses during the divergence of the four lineages, and are associated with structural genome modifications that may have a direct relation with the mode of transmission, adaptation to specific environments and pathogenicity of each organism.

29 CFR 452.33 - Persons who may be candidates and hold office; elections at conventions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... title IV. If members in good standing are denied the right to be candidates by the imposition of... delegates elected by secret ballot, protection of the right to be a candidate and to hold office is afforded...

5 CFR 1312.5 - Authority to classify.

Code of Federal Regulations, 2012 CFR

2012-01-01

... classify information or material under this part shall be limited to those officials concerned with matters..., to assign original classifications as indicated to information or material that is originated by OMB... International Affairs. (iv) Associate Director for Natural Resources, Energy and Science. (2) Secret and below...

5 CFR 1312.5 - Authority to classify.

Code of Federal Regulations, 2013 CFR

2013-01-01

... classify information or material under this part shall be limited to those officials concerned with matters..., to assign original classifications as indicated to information or material that is originated by OMB... International Affairs. (iv) Associate Director for Natural Resources, Energy and Science. (2) Secret and below...

5 CFR 1312.5 - Authority to classify.

Code of Federal Regulations, 2014 CFR

2014-01-01

... classify information or material under this part shall be limited to those officials concerned with matters..., to assign original classifications as indicated to information or material that is originated by OMB... International Affairs. (iv) Associate Director for Natural Resources, Energy and Science. (2) Secret and below...

Legionella pneumophila prevents proliferation of its natural host Acanthamoeba castellanii

PubMed Central

Mengue, Luce; Régnacq, Matthieu; Aucher, Willy; Portier, Emilie; Héchard, Yann; Samba-Louaka, Ascel

2016-01-01

Legionella pneumophila is a ubiquitous, pathogenic, Gram-negative bacterium responsible for legionellosis. Like many other amoeba-resistant microorganisms, L. pneumophila resists host clearance and multiplies inside the cell. Through its Dot/Icm type IV secretion system, the bacterium injects more than three hundred effectors that modulate host cell physiology in order to promote its own intracellular replication. Here we report that L. pneumophila prevents proliferation of its natural host Acanthamoeba castellanii. Infected amoebae could not undergo DNA replication and no cell division was observed. The Dot/Icm secretion system was necessary for L. pneumophila to prevent the eukaryotic proliferation. The absence of proliferation was associated with altered amoebal morphology and with a decrease of mRNA transcript levels of CDC2b, a putative regulator of the A. castellanii cell cycle. Complementation of CDC28-deficient Saccharomyces cerevisiae by the CDC2b cDNA was sufficient to restore proliferation of CDC28-deficient S. cerevisiae and suggests for the first time that CDC2b from A. castellanii could be functional and a bona fide cyclin-dependent kinase. Hence, our results reveal that L. pneumophila impairs proliferation of A. castellanii and this effect could involve the cell cycle protein CDC2b. PMID:27805070

Culture of prostate epithelial cells of the rhesus monkey on extracellular matrix substrate: influence of steroids and insulin-like growth factors.

PubMed

Udayakumar, T S; Jeyaraj, D A; Rajalakshmi, M; Sharma, R S

1999-09-01

Rhesus monkey prostate epithelial cells from the cranial lobe were isolated and cultured in flasks coated either with collagen IV or laminin. The effects of stromal cell medium, androgens and growth factors on cell number, thymidine incorporation and secretory activity were assessed. The results indicate that dihydrotestosterone (DHT) and androstenedione have stimulatory influences on cell proliferation and secretion in coated flasks. DHT was more effective in increasing cell number but the induction of secretory activity was similar with both steroids. The combination of IGF-I and -II resulted in inducing better cell proliferation and secretory activity than the individual IGFs but, of the two IGFs, IGF-I was more effective than IGF-II. DHT with IGFs was more potent in inducing proliferation, differentiation and secretion than androstenedione. Even in the absence of steroids or growth factors, colony formation and confluence occurred in coated flasks but cell differentiation and secretion only to a limited extent. In conclusion, we were able to establish an in vitro primary culture of prostate epithelial cells from rhesus monkey using extracellular matrix proteins, steroids and growth factors as additional supplements. This culture system may be useful to study prostate cell physiology and to identify drugs that can inhibit cell proliferation.

[Specific aspects and care of lung involvement in adults with cystic fibrosis].

PubMed

Pin, I; Grenet, D; Scheid, P; Domblides, P; Stern, M; Hubert, D

2000-08-01

Respiratory impairment is present in almost all adult cystic fibrosis patients and makes the prognosis. Viscous, infected and abundant secretions, inflammation and bronchial oedema, bronchoconstriction and respiratory muscle fatigue lead to airway obstruction, bronchiectasis and respiratory failure. The disease is preferentially located in the upper lobes. Exacerbations of the disease are due to bronchial infections and are often responsible for drops of the respiratory function. Regular spirometric surveillance is fundamental for the prognosis and the assessment of the effects of the treatment. Among adult patients chronic colonisation with mucoid and often multiresistant strains of Pseudomonas Aeruginosa are common. It is treated with i.v. high doses antibiotic courses and nebulized antibiotics between i.v. courses. Respiratory failure may require long term oxygen and non invasive mechanical ventilation. Systemic hypervascularization around the bronchiectasis may lead to moderate to severe hemoptysis, which may require embolization. Pneumothorax are associated with poor prognosis and are treated by pleural drainage and if failure by thoracoscopy.

Genetic mapping of secretion and functional determinants of the Vibrio cholerae TcpF colonization factor.

PubMed

Krebs, Shelly J; Kirn, Thomas J; Taylor, Ronald K

2009-06-01

Colonization of the human small intestine by Vibrio cholerae requires the type IV toxin-coregulated pilus (TCP). TcpF, which is encoded within the tcp operon, is secreted from the bacterial cell by the TCP apparatus and is also essential for colonization. Bacteria lacking tcpF are deficient in colonization, and anti-TcpF antibodies are protective in the infant mouse cholera model. In order to elucidate the regions of the protein that are required for secretion through the TCP apparatus and for its function in colonization, random mutagenesis of tcpF was performed. Analysis of these mutants suggests that multiple regions throughout the protein influence extracellular secretion and that determinants near the C terminus are important for the function of TcpF in colonization. The TcpF proteins of certain environmental V. cholerae isolates with 31% to 66% identity to pathogenic V. cholerae TcpF showed higher similarity in regions identified as secretion determinants but diverged in regions found to be important for colonization. These environmental TcpF proteins are secreted from the pathogenic strain; however, they do not mediate colonization in the infant mouse model. Here we provide genetic evidence pointing toward regions of TcpF that influence secretion, as well as regions that play an important role in in vivo colonization.

Gene Flow Across Genus Barriers – Conjugation of Dinoroseobacter shibae’s 191-kb Killer Plasmid into Phaeobacter inhibens and AHL-mediated Expression of Type IV Secretion Systems

PubMed Central

Patzelt, Diana; Michael, Victoria; Päuker, Orsola; Ebert, Matthias; Tielen, Petra; Jahn, Dieter; Tomasch, Jürgen; Petersen, Jörn; Wagner-Döbler, Irene

2016-01-01

Rhodobacteraceae harbor a conspicuous wealth of extrachromosomal replicons (ECRs) and therefore the exchange of genetic material via horizontal transfer has been supposed to be a major evolutionary driving force. Many plasmids in this group encode type IV secretion systems (T4SS) that are expected to mediate transfer of proteins and/or DNA into host cells, but no experimental evidence of either has yet been provided. Dinoroseobacter shibae, a species of the Roseobacter group within the Rhodobacteraceae family, contains five ECRs that are crucial for anaerobic growth, survival under starvation and the pathogenicity of this model organism. Here we tagged two syntenous but compatible RepABC-type plasmids of 191 and 126-kb size, each encoding a T4SS, with antibiotic resistance genes and demonstrated their conjugational transfer into a distantly related Roseobacter species, namely Phaeobacter inhibens. Pulsed field gel electrophoresis showed transfer of those replicons into the recipient both individually but also together documenting the efficiency of conjugation. We then studied the influence of externally added quorum sensing (QS) signals on the expression of the T4SS located on the sister plasmids. A QS deficient D. shibae null mutant (ΔluxI1) lacking synthesis of N-acyl-homoserine lactones (AHLs) was cultivated with a wide spectrum of chemically diverse long-chain AHLs. All AHLs with lengths of the acid side-chain ≥14 reverted the ΔluxI1 phenotype to wild-type. Expression of the T4SS was induced up to log2 ∼3fold above wild-type level. We hypothesize that conjugation in roseobacters is QS-controlled and that the QS system may detect a wide array of long-chain AHLs at the cell surface. PMID:27303368

The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus.

PubMed

Ng, Dixon; Harn, Tony; Altindal, Tuba; Kolappan, Subramania; Marles, Jarrad M; Lala, Rajan; Spielman, Ingrid; Gao, Yang; Hauke, Caitlyn A; Kovacikova, Gabriela; Verjee, Zia; Taylor, Ronald K; Biais, Nicolas; Craig, Lisa

2016-12-01

Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system.

Collagen type IV at the fetal-maternal interface.

PubMed

Oefner, C M; Sharkey, A; Gardner, L; Critchley, H; Oyen, M; Moffett, A

2015-01-01

Extracellular matrix proteins play a crucial role in influencing the invasion of trophoblast cells. However the role of collagens and collagen type IV (col-IV) in particular at the implantation site is not clear. Immunohistochemistry was used to determine the distribution of collagen types I, III, IV and VI in endometrium and decidua during the menstrual cycle and the first trimester of pregnancy. Expression of col-IV alpha chains during the reproductive cycle was determined by qPCR and protein localisation by immunohistochemistry. The structure of col-IV in placenta was examined using transmission electron microscopy. Finally, the expression of col-IV alpha chain NC1 domains and collagen receptors was localised by immunohistochemistry. Col-IV alpha chains were selectively up-regulated during the menstrual cycle and decidualisation. Primary extravillous trophoblast cells express collagen receptors and secrete col-IV in vitro and in vivo, resulting in the increased levels found in decidua basalis compared to decidua parietalis. A novel expression pattern of col-IV in the mesenchyme of placental villi, as a three-dimensional network, was found. NC1 domains of col-IV alpha chains are known to regulate tumour cell migration and the selective expression of these domains in decidua basalis compared to decidua parietalis was determined. Col-IV is expressed as novel forms in the placenta. These findings suggest that col-IV not only represents a structural protein providing tissue integrity but also influences the invasive behaviour of trophoblast cells at the implantation site. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Peptide Oxytocin Antagonist F-792, When Given Systemically, Does Not Act Centrally in Lactating Rats.

PubMed

Leng, G; Russell, J A

2016-04-01

Oxytocin secreted by nerve terminals in the posterior pituitary has important actions for ensuring a successful outcome of pregnancy: it stimulates uterine contractions that lead to birth and it is essential in the milk-ejection reflex, enabling milk to be expelled from the mammary glands into the mouths of suckling young. Oxytocin also has important actions in the brain: released from dendrites of neurones that innervate the posterior pituitary, oxytocin auto-excites the neurones to fire action potentials in co-ordinated bursts, causing secretion of pulses of oxytocin. Central oxytocin actions are blocked by an oxytocin antagonist given into the brain and, consequently, milk transfer stops. Systemic peptide oxytocin antagonist (atosiban) treatment is used clinically in management of pre-term labour, a major obstetric problem. Hence, it is important to know whether an oxytocin antagonist given peripherally can enter the brain and interfere with central oxytocin actions. In the present study, we tested F792, a peptide oxytocin antagonist. In urethane-anaesthetised suckled rats, we show that the mammary gland responsiveness to oxytocin is blocked by i.v. injections of 7 μg/kg of F792, and the milk-ejection reflex is blocked when F792 is given directly into the brain at a dose of 0.2 μg. To critically test whether F792 given systemically can enter the brain, we recorded the suckling- and oxytocin-induced burst-firing of individual antidromically identified oxytocin neurones in the paraventricular nucleus. Given systemically at 100 μg/kg i.v., F792 acted only peripherally, blocking the milk-ejecting actions of oxytocin, but not the burst-firing of oxytocin neurones during suckling (n = 5 neurones in five rats). Hence, this peptide oxytocin antagonist does not enter the brain from the circulation to interfere with an essential oxytocin function in the brain. Furthermore, the functions of oxytocin in the brain evidently cannot be explored with a systemic peptide antagonist. © 2015 British Society for Neuroendocrinology.

Entrapment of H1N1 Influenza Virus Derived Conserved Peptides in PLGA Nanoparticles Enhances T Cell Response and Vaccine Efficacy in Pigs.

PubMed

Hiremath, Jagadish; Kang, Kyung-il; Xia, Ming; Elaish, Mohamed; Binjawadagi, Basavaraj; Ouyang, Kang; Dhakal, Santosh; Arcos, Jesus; Torrelles, Jordi B; Jiang, X; Lee, Chang Won; Renukaradhya, Gourapura J

2016-01-01

Pigs are believed to be one of the important sources of emerging human and swine influenza viruses (SwIV). Influenza virus conserved peptides have the potential to elicit cross-protective immune response, but without the help of potent adjuvant and delivery system they are poorly immunogenic. Biodegradable polylactic-co-glycolic acid (PLGA) nanoparticle (PLGA-NP) based vaccine delivery system enhances cross-presentation of antigens by the professional antigen presenting cells. In this study, Norovirus P particle containing SwIV M2e (extracellular domain of the matrix protein 2) chimera and highly conserved two each of H1N1 peptides of pandemic 2009 and classical human influenza viruses were entrapped in PLGA-NPs. Influenza antibody-free pigs were vaccinated with PLGA-NPs peptides cocktail vaccine twice with or without an adjuvant, Mycobacterium vaccae whole cell lysate, intranasally as mist. Vaccinated pigs were challenged with a virulent heterologous zoonotic SwIV H1N1, and one week later euthanized and the lung samples were analyzed for the specific immune response and viral load. Clinically, pigs vaccinated with PLGA-NP peptides vaccine had no fever and flu symptoms, and the replicating challenged SwIV was undetectable in the bronchoalveolar lavage fluid. Immunologically, PLGA-NP peptides vaccination (without adjuvant) significantly increased the frequency of antigen-specific IFNγ secreting CD4 and CD8 T cells response in the lung lymphocytes, despite not boosting the antibody response both at pre- and post-challenge. In summary, our data indicated that nanoparticle-mediated delivery of conserved H1N1 influenza peptides induced the virus specific T cell response in the lungs and reduced the challenged heterologous virus load in the airways of pigs.

Polyglycine hydrolases: fungal b-lactamase-like endoproteases that cleave polyglycine regions within plant class IV chitinases

USDA-ARS?s Scientific Manuscript database

Polyglycine hydrolases are secreted fungal proteases that cleave glycine-glycine peptide bonds in the inter-domain linker region of specific plant defense chitinases. Previously, we reported the catalytic activity of polyglycine hydrolases from the phytopathogens Epicoccum sorghi (Es-cmp) and Cochli...

Chitinase modifying proteins from phylogenetically distinct lineages of Brassica pathogens

USDA-ARS?s Scientific Manuscript database

Chitinase modifying proteins (CMPs) are secreted fungal proteases that truncate specific plant class IV chitinases by cleaving peptide bonds in their amino termini. We recently identified a CMP from the Zea mays (maize) pathogen Fusarium verticillioides and found that it is a member of the fungalysi...

ABSORPTION, DISTRIBUTION AND MILK SECRETION OF RADIONUCLIDES BY THE DAIRY COW - V. RADIOTUNGSTEN

EPA Science Inventory

In a study conducted in 1969 and 1970 lactating cows were given oral or intravenous (I.V.) doses of radiotungsten. Blood, milk, urine and feces were collected and analyzed to measure transfer rate and quantity of tungsten eliminated over an extended period during and after exposu...

New insights into Acinetobacter baumannii pathogenesis revealed by high-density pyrosequencing and transposon mutagenesis.

PubMed

Smith, Michael G; Gianoulis, Tara A; Pukatzki, Stefan; Mekalanos, John J; Ornston, L Nicholas; Gerstein, Mark; Snyder, Michael

2007-03-01

Acinetobacter baumannii has emerged as an important and problematic human pathogen as it is the causative agent of several types of infections including pneumonia, meningitis, septicemia, and urinary tract infections. We explored the pathogenic content of this harmful pathogen using a combination of DNA sequencing and insertional mutagenesis. The genome of this organism was sequenced using a strategy involving high-density pyrosequencing, a novel, rapid method of high-throughput sequencing. Excluding the rDNA repeats, the assembled genome is 3,976,746 base pairs (bp) and has 3830 ORFs. A significant fraction of ORFs (17.2%) are located in 28 putative alien islands, indicating that the genome has acquired a large amount of foreign DNA. Consistent with its role in pathogenesis, a remarkable number of the islands (16) contain genes implicated in virulence, indicating the organism devotes a considerable portion of its genes to pathogenesis. The largest island contains elements homologous to the Legionella/Coxiella Type IV secretion apparatus. Type IV secretion systems have been demonstrated to be important for virulence in other organisms and thus are likely to help mediate pathogenesis of A. baumannii. Insertional mutagenesis generated avirulent isolates of A. baumannii and verified that six of the islands contain virulence genes, including two novel islands containing genes that lacked homology with others in the databases. The DNA sequencing approach described in this study allows the rapid elucidation of the DNA sequence of any microbe and, when combined with genetic screens, can identify many novel genes important for microbial pathogenesis.

Dexamethasone increases production of C-type natriuretic peptide in the sheep brain.

PubMed

Wilson, Michele O; McNeill, Bryony A; Barrell, Graham K; Prickett, Timothy C R; Espiner, Eric A

2017-10-01

Although C-type natriuretic peptide (CNP) has high abundance in brain tissues and cerebrospinal fluid (CSF), the source and possible factors regulating its secretion within the central nervous system (CNS) are unknown. Here we report the dynamic effects of a single IV bolus of dexamethasone or saline solution on plasma, CSF, CNS and pituitary tissue content of CNP products in adult sheep, along with changes in CNP gene expression in selected tissues. Both CNP and NTproCNP (the amino-terminal product of proCNP) in plasma and CSF showed dose-responsive increases lasting 12-16 h after dexamethasone, whereas other natriuretic peptides were unaffected. CNS tissue concentrations of CNP and NTproCNP were increased by dexamethasone in all of the 12 regions examined. Abundance was highest in limbic tissues, pons and medulla oblongata. Relative to controls, CNP gene expression ( NPPC ) was upregulated by dexamethasone in 5 of 7 brain tissues examined. Patterns of responses differed in pituitary tissue. Whereas the abundance of CNP in both lobes of the pituitary gland greatly exceeded that of brain tissues, neither CNP nor NTproCNP concentration was affected by dexamethasone, despite an increase in NPPC expression. This is the first report of enhanced production and secretion of CNP in brain tissues in response to a corticosteroid. Activation of CNP secretion within CNS tissues by dexamethasone, not exhibited by other natriuretic peptides, suggests an important role for CNP in settings of acute stress. Differential findings in pituitary tissues likely relate to altered processing of proCNP storage and secretion. © 2017 Society for Endocrinology.

Differential interactions of virulent and non-virulent H. parasuis strains with naïve or swine influenza virus pre-infected dendritic cells.

PubMed

Mussá, Tufária; Rodríguez-Cariño, Carolina; Sánchez-Chardi, Alejandro; Baratelli, Massimiliano; Costa-Hurtado, Mar; Fraile, Lorenzo; Domínguez, Javier; Aragon, Virginia; Montoya, María

2012-11-16

Pigs possess a microbiota in the upper respiratory tract that includes Haemophilus parasuis. Pigs are also considered the reservoir of influenza viruses and infection with this virus commonly results in increased impact of bacterial infections, including those by H. parasuis. However, the mechanisms involved in host innate responses towards H. parasuis and their implications in a co-infection with influenza virus are unknown. Therefore, the ability of a non-virulent H. parasuis serovar 3 (SW114) and a virulent serovar 5 (Nagasaki) strains to interact with porcine bone marrow dendritic cells (poBMDC) and their modulation in a co-infection with swine influenza virus (SwIV) H3N2 was examined. At 1 hour post infection (hpi), SW114 interaction with poBMDC was higher than that of Nagasaki, while at 8 hpi both strains showed similar levels of interaction. The co-infection with H3N2 SwIV and either SW114 or Nagasaki induced higher levels of IL-1β, TNF-α, IL-6, IL-12 and IL-10 compared to mock or H3N2 SwIV infection alone. Moreover, IL-12 and IFN-α secretion differentially increased in cells co-infected with H3N2 SwIV and Nagasaki. These results pave the way for understanding the differences in the interaction of non-virulent and virulent strains of H. parasuis with the swine immune system and their modulation in a viral co-infection.

Solid-to-solid oxidation of a vanadium(IV) to a vanadium(V) compound: chemisty of a sulfur-containing siderophore.

PubMed

Chatterjee, Pabitra B; Crans, Debbie C

2012-09-03

Visible light facilitates a solid-to-solid photochemical aerobic oxidation of a hunter-green microcrystalline oxidovanadium(IV) compound (1) to form a black powder of cis-dioxidovanadium(V) (2) at ambient temperature. The siderophore ligand pyridine-2,6-bis(thiocarboxylic acid), H(2)L, is secreted by a microorganism from the Pseudomonas genus. This irreversible transformation of a metal monooxo to a metal dioxo complex in the solid state in the absence of solvent is unprecedented. It serves as a proof-of-concept reaction for green chemistry occurring in solid matrixes.

Cell biology and immunology lessons taught by Legionella pneumophila.

PubMed

Zhu, Wenhan; Luo, Zhao-Qing

2016-01-01

Legionella pneumophila is a facultative intracellular pathogen capable of replicating within a broad range of hosts. One unique feature of this pathogen is the cohort of ca. 300 virulence factors (effectors) delivered into host cells via its Dot/Icm type IV secretion system. Study of these proteins has produced novel insights into the mechanisms of host function modulation by pathogens, the regulation of essential processes of eukaryotic cells and of immunosurveillance. In this review, we will briefly discuss the roles of some of these effectors in the creation of a niche permissive for bacterial replication in phagocytes and recent advancements in the dissection of the innate immune detection mechanisms by challenging immune cells with L. pneumophila.

Legionella and Coxiella effectors: strength in diversity and activity.

PubMed

Qiu, Jiazhang; Luo, Zhao-Qing

2017-10-01

Legionella pneumophila and Coxiella burnetii are two evolutionarily related intracellular pathogens that use the Dot/Icm type IV secretion system to translocate effectors into host cells. These effectors are essential for the establishment of membrane-bound compartments known as replication vacuoles, which enable the survival and replication of bacteria inside host cells. The effectors interfere with diverse signalling pathways to co-opt host processes, such as vesicle trafficking, ubiquitylation, gene expression and lipid metabolism, to promote pathogen survival. In this Review, we explore Dot/Icm effectors from L. pneumophila and C. burnetii as key virulence factors, and we examine the biochemical and cell biological functions of these effectors and their roles in our understanding of bacterial virulence.

Mobile DNA in the pathogenic Neisseria

PubMed Central

Obergfell, Kyle P.; Seifert, H. Steven

2015-01-01

The genus Neisseria contains two pathogenic species of notable public health concern: Neisseria gonorrhoeae and Neisseria meningitidis. These pathogens display a notable ability to undergo frequent programmed recombination events. The recombination mediated pathways of transformation and pilin antigenic variation in the Neisseria are well studied systems that are critical for pathogenesis. Here we will detail the conserved and unique aspects of transformation and antigenic variation in the Neisseria. Transformation will be followed from initial DNA binding through recombination into the genome with consideration to the factors necessary at each step. Additional focus is paid to the unique type IV secretion system that mediates donation of transforming DNA in the pathogenic Neisseria. The pilin antigenic variation system uses programed recombinations to alter a major surface determinant which allows immune avoidance and promotes infection. We discuss the trans- and cis- acting factors which facilitate pilin antigenic variation and present the current understanding of the mechanisms involved in the process. PMID:25866700

Proteinases secreted by Fasciola hepatica degrade extracellular matrix and basement membrane components.

PubMed

Berasaín, P; Goñi, F; McGonigle, S; Dowd, A; Dalton, J P; Frangione, B; Carmona, C

1997-02-01

The invasive stages of the parasitic trematode Fasciola hepatica release proteinases into the medium in which they are maintained. In this study, we investigated the interaction of F. hepatica excretory/secretory (E/S) products and 2 cysteine proteinases (CL1 and CL2) purified from these products with extracellular matrix and basement membrane macromolecules. Fasciola hepatica E/S products contained collagenolytic activity on fibrillar types I and III collagen as well as basement membrane type IV collagen. CL1 and CL2 were capable of degrading acid-soluble type III and type IV collagen but not insoluble type I collagen. In contrast, neither the E/S products nor the purified CL1 and CL2 showed elastinolytic activity. Fibronectin and laminin were degraded by E/S products and by CL1 and CL2. Sequence analysis of fibronectin degradation products showed that the fragments obtained corresponded to complete biologically active domains. These results indicate that the cysteine proteinases secreted by F. hepatica may be involved in the process of tissue invasion by the parasite.

Quantitative proteomics unravels that the post-transcriptional regulator Crc modulates the generation of vesicles and secreted virulence determinants of Pseudomonas aeruginosa.

PubMed

Reales-Calderón, Jose Antonio; Corona, Fernando; Monteoliva, Lucía; Gil, Concha; Martínez, Jose Luis

2015-09-01

Crc is a post-transcriptional regulator in Pseudomonas aeruginosa that modulates its metabolism, but also its susceptibility to antibiotics and virulence. Most of P. aeruginosa virulence factors are secreted or engulfed in vesicles. A Crc deficient mutant was created and the extracellular vesicles associated exoproteome and the vesicle-free secretome was quantified using iTRAQ. Fifty vesicles-associated proteins were more abundant and 14 less abundant in the Crc-defective strain, whereas 37 were more abundant and 17 less abundant in the vesicle-free secretome. Different virulence determinants, such as ToxA, protease IV, azurin, chitin-binding protein, PlcB and Hcp1, were less abundant in the Crc-defective mutant. We also observed that the crc mutant presented an impaired vesicle-associated secretion of quorum sensing signal molecules and less cytotoxicity than its wild-type strain, in agreement with the low secretion of proteins related to virulence. Our results offer new insights into the mechanisms by which Crc regulates P. aeruginosa virulence, through the modulation of vesicle formation and secretion of both virulence determinants and quorum sensing signals.

Evaluation of beta-cell sensitivity to glucose and first-phase insulin secretion in obese dogs.

PubMed

Verkest, Kurt R; Fleeman, Linda M; Rand, Jacquie S; Morton, John M

2011-03-01

To compare beta-cell sensitivity to glucose, first-phase insulin secretion, and glucose tolerance between dogs with naturally occurring obesity of > 2 years' duration and lean dogs. 17 client-owned obese or lean dogs. Frequently sampled IV glucose tolerance tests were performed with minimal model analysis on 6 obese dogs and matched controls. Glucagon stimulation tests were performed on 5 obese dogs and matched controls. Obese dogs were half as sensitive to the effects of insulin as lean dogs. Plasma glucose concentrations after food withholding did not differ significantly between groups; plasma insulin concentrations were 3 to 4 times as great in obese as in lean dogs. Obese dogs had plasma insulin concentrations twice those of lean dogs after administration of glucose and 4 times as great after administration of glucagon. First-phase insulin secretion was greater in obese dogs. Obese dogs compensated for obesity-induced insulin resistance by secreting more insulin. First-phase insulin secretion and beta-cell glucose sensitivity were not lost despite years of obesity-induced insulin resistance and compensatory hyperinsulinemia. These findings help explain why dogs, unlike cats and humans, have not been documented to develop type 2 diabetes mellitus.

Suppression of hedgehog signaling regulates hepatic stellate cell activation and collagen secretion.

PubMed

Li, Tao; Leng, Xi-Sheng; Zhu, Ji-Ye; Wang, Gang

2015-01-01

Hepatic stellate cells (HSCs) play an important role in liver fibrosis. This study investigates the expression of hedgehog in HSC and the role of hedgehog signaling on activation and collagen secretion of HSC. Liver ex vivo perfusion with collagenase IV and density gradient centrifugation were used to isolate HSC. Expression of hedgehog signaling components Ihh, Smo, Ptc, Gli2 and Gli3 in HSC were detected by RT-PCR. Hedgehog siRNA vectors targeting Ihh, Smo and Gli2 were constructed and transfected into HSC respectively. Suppression of hedgehog signaling were detected by SYBR Green fluorescence quantitative RT-PCR. Effects of hedgehog signaling inhibition on HSC activation and collagen I secretion were analyzed. Hedgehog signaling components Ihh, Smo, Ptc, Gli2 and Gli3 were expressed in HSC. siRNA vectors targeting Ihh, Smo and Gli2 were successfully constructed and decreased target gene expression. Suppression of hedgehog signaling significantly decreased the expression of α-SMA in HSC (P<0.01). Collagen type I secretion of HSC were also significantly decreased (P<0.01). In summary, HSC activation and collagen secretion can be regulated by hedgehog signaling. Hedgehog may play a role in the pathogenesis of liver fibrosis.

Proteolytic processing of lysyl oxidase-like-2 in the extracellular matrix is required for crosslinking of basement membrane collagen IV.

PubMed

López-Jiménez, Alberto J; Basak, Trayambak; Vanacore, Roberto M

2017-10-13

Lysyl oxidase-like-2 (LOXL2) is an enzyme secreted into the extracellular matrix that crosslinks collagens by mediating oxidative deamination of lysine residues. Our previous work demonstrated that this enzyme crosslinks the 7S domain, a structural domain that stabilizes collagen IV scaffolds in the basement membrane. Despite its relevant role in extracellular matrix biosynthesis, little is known about the structural requirements of LOXL2 that enable collagen IV crosslinking. In this study, we demonstrate that LOXL2 is processed extracellularly by serine proteases, generating a 65-kDa form lacking the first two scavenger receptor cysteine-rich domains. Site-specific mutagenesis to prevent proteolytic processing generated a full-length enzyme that is active in vitro toward a soluble substrate, but fails to crosslink insoluble collagen IV within the extracellular matrix. In contrast, the processed form of LOXL2 binds to collagen IV and crosslinks the 7S domain. Together, our data demonstrate that proteolytic processing is an important event that allows LOXL2-mediated crosslinking of basement membrane collagen IV. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

The acute effect of a mineralocorticoid receptor agonist on corticotrope secretion in Addison's disease.

PubMed

Berardelli, R; Karamouzis, I; D'Angelo, V; Fussotto, B; Minetto, M A; Ghigo, E; Giordano, R; Arvat, E

2016-05-01

Mineralocorticoid receptors (MR) in the hippocampus display an important role in the control of hypothalamic-pituitary-adrenal (HPA) axis, mediating the ''proactive'' feedback of glucocorticoids (GC). Fludrocortisone (FC), a potent MR agonist, has been shown to decrease HPA activity through a hippocampal mechanism. Since it has been demonstrated that FC shows a significant inhibition of the HPA axis response to hCRH stimulus in normal subjects, also at doses usually administered as replacement therapy in patients with Addison's disease, an FC effect at MRs in human pituitary or a GR-pituitary agonism stronger than believed until now has been postulated. Ten patients affected by autoimmune Addison's disease received: (1) placebo p.o. + placebo i.v., (2) hydrocortisone (H) 10 mg p.o. + placebo i.v., (3) FC 0.1 mg p.o. + placebo i.v., (4) FC 0.1 mg and H 10 mg p.o. + placebo i.v. to verify a possible GR FC-mediated effect that might display a repercussion on the GC-replacement therapy. H reduced ACTH (p < 0.01) and increased cortisol levels (p < 0.01) with respect to the placebo session, while FC did not affect either ACTH or cortisol levels compared to placebo, and higher ACTH and lower cortisol levels (p < 0.03 and p < 0.01) were observed compared with the H session; furthermore the co-administration of FC + H showed ACTH and cortisol profiles similar to that observed during H alone. Our study showed a lack of FC effect on corticotrope secretion in Addison's disease, thus making unlikely the hypothesis of its GR pituitary agonism and the risk of glucocorticoid excess in primary adrenal insufficiency.

Tolerance to 3,4-Methylenedioxymethamphetamine (MDMA) in Rats Exposed to Single High-Dose Binges

PubMed Central

Baumann, Michael H.; Clark, Robert D.; Franken, Frederick H.; Rutter, John J.; Rothman, Richard B.

2008-01-01

3,4-Methylenedioxymethamphetamine (MDMA or Ecstasy) stimulates the transporter-mediated release of monoamines, including serotonin (5-HT). High-dose exposure to MDMA causes persistent 5-HT deficits (e.g., depletion of brain 5-HT) in animals, yet the functional and clinical relevance of such deficits are poorly defined. Here we examine functional consequences of MDMA-induced 5-HT depletions in rats. Male rats received binges of 3 ip injections of MDMA or saline, one injection every 2 h; MDMA was given at a threshold pharmacological dose (1.5 mg/kg × 3, low dose) or at a 5-fold higher amount (7.5 mg/kg × 3, high dose). One week later, jugular catheters and intracerebral guide cannulae were implanted. Two weeks after binges, rats received acute iv challenge injections of 1 and 3 mg/kg MDMA. Neuroendocrine effects evoked by iv MDMA (prolactin and corticosterone secretion) were assessed via serial blood sampling, while neurochemical effects (5-HT and dopamine release) were assessed via microdialysis in brain. MDMA binges elevated core temperatures only in the high-dose group, with these same rats exhibiting ~50% loss of forebrain 5-HT two weeks later. Prior exposure to MDMA did not alter baseline plasma hormones or dialysate monoamines, and effects of iv MDMA were similar in saline and low-dose groups. By contrast, rats pretreated with high-dose MDMA displayed significant reductions in evoked hormone secretion and 5-HT release when challenged with iv MDMA. As tolerance developed only in rats exposed to high-dose binges, hyperthermia and 5-HT depletion are implicated in this phenomenon. Our results suggest that MDMA tolerance in humans may reflect 5-HT deficits which could contribute to further dose escalation. PMID:18313226

Bartonella and Brucella—Weapons and Strategies for Stealth Attack

PubMed Central

Ben-Tekaya, Houchaima; Gorvel, Jean-Pierre; Dehio, Christoph

2013-01-01

Bartonella spp. and Brucella spp. are closely related α-proteobacterial pathogens that by distinct stealth-attack strategies cause chronic infections in mammals including humans. Human infections manifest by a broad spectrum of clinical symptoms, ranging from mild to fatal disease. Both pathogens establish intracellular replication niches and subvert diverse pathways of the host’s immune system. Several virulence factors allow them to adhere to, invade, proliferate, and persist within various host-cell types. In particular, type IV secretion systems (T4SS) represent essential virulence factors that transfer effector proteins tailored to recruit host components and modulate cellular processes to the benefit of the bacterial intruders. This article puts the remarkable features of these two pathogens into perspective, highlighting the mechanisms they use to hijack signaling and trafficking pathways of the host as the basis for their stealthy infection strategies. PMID:23906880

The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus

PubMed Central

Harn, Tony; Spielman, Ingrid; Gao, Yang; Kovacikova, Gabriela; Biais, Nicolas

2016-01-01

Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system. PMID:27992883

Evolutionary Dynamics of Pathoadaptation Revealed by Three Independent Acquisitions of the VirB/D4 Type IV Secretion System in Bartonella.

PubMed

Harms, Alexander; Segers, Francisca H I D; Quebatte, Maxime; Mistl, Claudia; Manfredi, Pablo; Körner, Jonas; Chomel, Bruno B; Kosoy, Michael; Maruyama, Soichi; Engel, Philipp; Dehio, Christoph

2017-03-01

The α-proteobacterial genus Bartonella comprises a group of ubiquitous mammalian pathogens that are studied as a model for the evolution of bacterial pathogenesis. Vast abundance of two particular phylogenetic lineages of Bartonella had been linked to enhanced host adaptability enabled by lineage-specific acquisition of a VirB/D4 type IV secretion system (T4SS) and parallel evolution of complex effector repertoires. However, the limited availability of genome sequences from one of those lineages as well as other, remote branches of Bartonella has so far hampered comprehensive understanding of how the VirB/D4 T4SS and its effectors called Beps have shaped Bartonella evolution. Here, we report the discovery of a third repertoire of Beps associated with the VirB/D4 T4SS of B. ancashensis, a novel human pathogen that lacks any signs of host adaptability and is only distantly related to the two species-rich lineages encoding a VirB/D4 T4SS. Furthermore, sequencing of ten new Bartonella isolates from under-sampled lineages enabled combined in silico analyses and wet lab experiments that suggest several parallel layers of functional diversification during evolution of the three Bep repertoires from a single ancestral effector. Our analyses show that the Beps of B. ancashensis share many features with the two other repertoires, but may represent a more ancestral state that has not yet unleashed the adaptive potential of such an effector set. We anticipate that the effectors of B. ancashensis will enable future studies to dissect the evolutionary history of Bartonella effectors and help unraveling the evolutionary forces underlying bacterial host adaptation. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Crystal Structure of a Type IV Pilus Assembly ATPase: Insights into the Molecular Mechanism of PilB from Thermus thermophilus

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

Mancl, Jordan M.; Black, Wesley P.; Robinson, Howard

Type IV pili (T4P) mediate bacterial motility and virulence. The PilB/GspE family ATPases power the assembly of T4P and type 2 secretion systems. We determined the structure of the ATPase region of PilB (PilB ATP) in complex with ATPγS to provide a model of a T4P assembly ATPase and a view of a PilB/GspE family hexamer at better than 3-Å resolution. Spatial positioning and conformations of the protomers suggest a mechanism of force generation. All six PilB ATP protomers contain bound ATPγS. Two protomers form a closed conformation poised for ATP hydrolysis. The other four molecules assume an open conformationmore » but separate into two pairs with distinct active-site accessibilities. We propose that one pair represents the post-hydrolysis phase while the other pair appears poised for ADP/ATP exchange. In conclusion, collectively, the data suggest that T4P assembly is powered by coordinating concurrent substrate binding with ATP hydrolysis across the PilB hexamer.« less

Crystal Structure of a Type IV Pilus Assembly ATPase: Insights into the Molecular Mechanism of PilB from Thermus thermophilus

DOE PAGES

Mancl, Jordan M.; Black, Wesley P.; Robinson, Howard; ...

2016-09-22

Type IV pili (T4P) mediate bacterial motility and virulence. The PilB/GspE family ATPases power the assembly of T4P and type 2 secretion systems. We determined the structure of the ATPase region of PilB (PilB ATP) in complex with ATPγS to provide a model of a T4P assembly ATPase and a view of a PilB/GspE family hexamer at better than 3-Å resolution. Spatial positioning and conformations of the protomers suggest a mechanism of force generation. All six PilB ATP protomers contain bound ATPγS. Two protomers form a closed conformation poised for ATP hydrolysis. The other four molecules assume an open conformationmore » but separate into two pairs with distinct active-site accessibilities. We propose that one pair represents the post-hydrolysis phase while the other pair appears poised for ADP/ATP exchange. In conclusion, collectively, the data suggest that T4P assembly is powered by coordinating concurrent substrate binding with ATP hydrolysis across the PilB hexamer.« less

High-quality permanent draft genome sequence of the Bradyrhizobium elkanii type strain USDA 76T, isolated from Glycine max (L.) Merr

DOE PAGES

Reeve, Wayne; van Berkum, Peter; Ardley, Julie; ...

2017-03-04

Bradyrhizobium elkanii USDA 76 T (INSCD = ARAG00000000), the type strain for Bradyrhizobium elkanii, is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from an effective nitrogen-fixing root nodule of Glycine max (L. Merr) grown in the USA. Because of its significance as a microsymbiont of this economically important legume, B. elkanii USDA 76 T was selected as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria sequencing project. Here the symbiotic abilities of B. elkanii USDA 76 T are described, together with its genome sequence information and annotation. The 9,484,767 bpmore » high-quality draft genome is arranged in 2 scaffolds of 25 contigs, containing 9060 protein-coding genes and 91 RNA-only encoding genes. The B. elkanii USDA 76 T genome contains a low GC content region with symbiotic nod and fix genes, indicating the presence of a symbiotic island integration. A comparison of five B. elkanii genomes that formed a clique revealed that 356 of the 9060 protein coding genes of USDA 76 T were unique, including 22 genes of an intact resident prophage. A conserved set of 7556 genes were also identified for this species, including genes encoding a general secretion pathway as well as type II, III, IV and VI secretion system proteins. The type III secretion system has previously been characterized as a host determinant for Rj and/or rj soybean cultivars. Here we show that the USDA 76 T genome contains genes encoding all the type III secretion system components, including a translocon complex protein NopX required for the introduction of effector proteins into host cells. While many bradyrhizobial strains are unable to nodulate the soybean cultivar Clark (rj1), USDA 76 T was able to elicit nodules on Clark (rj1), although in reduced numbers, when plants were grown in Leonard jars containing sand or vermiculite. In these conditions, we postulate that the presence of NopX allows USDA 76 T to introduce various effector molecules into this host to enable nodulation.« less

High-quality permanent draft genome sequence of the Bradyrhizobium elkanii type strain USDA 76T, isolated from Glycine max (L.) Merr

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

Reeve, Wayne; van Berkum, Peter; Ardley, Julie

Bradyrhizobium elkanii USDA 76 T (INSCD = ARAG00000000), the type strain for Bradyrhizobium elkanii, is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from an effective nitrogen-fixing root nodule of Glycine max (L. Merr) grown in the USA. Because of its significance as a microsymbiont of this economically important legume, B. elkanii USDA 76 T was selected as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria sequencing project. Here the symbiotic abilities of B. elkanii USDA 76 T are described, together with its genome sequence information and annotation. The 9,484,767 bpmore » high-quality draft genome is arranged in 2 scaffolds of 25 contigs, containing 9060 protein-coding genes and 91 RNA-only encoding genes. The B. elkanii USDA 76 T genome contains a low GC content region with symbiotic nod and fix genes, indicating the presence of a symbiotic island integration. A comparison of five B. elkanii genomes that formed a clique revealed that 356 of the 9060 protein coding genes of USDA 76 T were unique, including 22 genes of an intact resident prophage. A conserved set of 7556 genes were also identified for this species, including genes encoding a general secretion pathway as well as type II, III, IV and VI secretion system proteins. The type III secretion system has previously been characterized as a host determinant for Rj and/or rj soybean cultivars. Here we show that the USDA 76 T genome contains genes encoding all the type III secretion system components, including a translocon complex protein NopX required for the introduction of effector proteins into host cells. While many bradyrhizobial strains are unable to nodulate the soybean cultivar Clark (rj1), USDA 76 T was able to elicit nodules on Clark (rj1), although in reduced numbers, when plants were grown in Leonard jars containing sand or vermiculite. In these conditions, we postulate that the presence of NopX allows USDA 76 T to introduce various effector molecules into this host to enable nodulation.« less

The influence of potato fibre on exocrine pancreatic secretions and on plasma levels of insulin, secretin and cholecystokinin in growing pigs.

PubMed

Jakob, S; Mosenthin, R; Thaela, M J; Weström, B R; Rehfeld, J F; Olsen, O; Karlsson, S; Ahrén, B; Ohlsson, A; Karlsson, B W; Pierzynowski, S G

2000-01-01

The effect of a potato fibre preparation on exocrine pancreatic secretions and on gastrointestinal hormone levels in plasma was studied in three 8 weeks old piglets that were surgically fitted with a jugular vein catheter for blood sampling, a pancreatic duct catheter and a T-shaped duodenal cannula for collection of pancreatic juice. The animals were fed for 2 weeks a control diet (experimental period 1), thereafter for 2 weeks the control diet supplemented with 2% potato fibre (experimental period 2) and for another 2 weeks the control diet again (experimental period 3). Additionally, intraduodenal (i.d.) infusions of the experimental diet, the control diet and potato fibre as well as i.v. infusions of a solution containing cholecystokinin (CCK) and secretin were administered. Potato fibre in the diet evoked in tendency an increase in the volume of secretion of pancreatic juice and a significant increase both in the mean values of the total protein content and total activities of lipase, trypsin and alpha-amylase when compared to the control diet. The i.d. infusion of the control diet, experimental diet and fibre infusate as well as the i.v. administration of the hormone infusate led to a spontaneous secretory response of the exocrine pancreas. Besides gastrointestinal hormones, such as CCK, other factors such as short chain fatty acids may be involved in the regulation of the exocrine pancreas.

Exosome-like vesicles with dipeptidyl peptidase IV in human saliva.

PubMed

Ogawa, Yuko; Kanai-Azuma, Masami; Akimoto, Yoshihiro; Kawakami, Hayato; Yanoshita, Ryohei

2008-06-01

Saliva contains a large number of proteins that participate in the protection of oral tissue. We found, for the first time, small vesicles (30-130 nm in diameter) in human whole saliva. Vesicles from saliva were identified by electron microscopy after isolation by gel-filtration on Sepharose CL-4B. They resemble exosomes, which are vesicles with an endosome-derived limiting membrane that are secreted by a diverse range of cell types. We performed a biochemical characterization of these vesicles by amino acid sequence analysis and Western blot analysis. We found that they contain dipeptidyl peptidase IV (DPP IV), galectin-3 and immunoglobulin A, which have potential to influence immune response. The DPP IV in the vesicles was metabolically active in cleaving substance P and glucose-dependent insulinotropic polypeptide to release N-terminal dipeptides. Our results demonstrate that human whole saliva contains exosome-like vesicles; they might participate in the catabolism of bioactive peptides and play a regulatory role in local immune defense in the oral cavity.

Co-evolution of chitinases from maize and other cereals with secreted proteases from Pleosporineae fungi

USDA-ARS?s Scientific Manuscript database

Plant class IV chitinases are composed of a carboxy-terminal chitinase domain that is attached, through a linker sequence, to a small amino-terminal domain that can be thought of as a structured peptide. While both the peptide-like domain and the chitinase domain share sequence homology throughout m...

Crystallographic structure of ChitA, a glycoside hydrolase family 19, plant class IV chitinase from Zea mays

USDA-ARS?s Scientific Manuscript database

Maize ChitA chitinase is composed of a small, hevein-like domain attached to a carboxy-terminal chitinase domain. During fungal ear rot, the hevein-like domain is cleaved by secreted fungal proteases to produce truncated forms of ChitA. Here, we report a structural and biochemical characterization o...

Identification of a chitinase modifying protein from Fusarium verticillioides: truncation of a host resistance protein by a fungalysin metalloprotease

USDA-ARS?s Scientific Manuscript database

Chitinase modifying proteins (cmps) are proteases, secreted by fungal pathogens, which truncate the plant class IV chitinases ChitA and ChitB during maize ear rot. Cmp activity has been characterized for Bipolaris zeicola and Stenocarpella maydis, but the identities of the proteases are not known. H...

Incidence and prognostic value of serotonin secretion in pancreatic neuroendocrine tumours.

PubMed

Zandee, Wouter T; van Adrichem, Roxanne C; Kamp, Kimberly; Feelders, Richard A; van Velthuysen, Marie-Louise F; de Herder, Wouter W

2017-08-01

Serotonin secretion occurs in approximately 1%-4% of patients with a pancreatic neuroendocrine tumour (PNET), but the incidence is not well defined. The aim of this study was to determine the incidence of serotonin secretion with and without carcinoid syndrome and the prognostic value for overall survival (OS). Data were collected from 255 patients with a PNET if 24-hours urinary 5-hydroxyindoleacetic acid excretion (5-HIAA) was assessed. Patients were diagnosed with serotonin secretion if 24-hours urinary 5-HIAA excretion was more than 3× the upper limit of normal (ULN) of 50 μmol/24 hours during follow-up. The effect of serotonin secretion on OS was estimated with uni- and multivariate analyses using a Cox regression. Two (0.8%) patients were diagnosed with carcinoid syndrome, and another 20 (7.8%) had a serotonin-secreting PNET without symptoms. These patients mostly had ENETS stage IV disease with high chromogranin A (CgA). Serotonin secretion was a negative prognostic factor in univariate analysis (HR 2.2, 95% CI: 1.27-3.81), but in multivariate analysis, only CgA>10× ULN (HR: 1.81, 95% CI: 1.10-2.98) and neuron-specific enolase (NSE) >ULN (HR: 3.51, 95% CI: 2.26-5.46) were predictors for OS. Immunohistochemical staining for serotonin was positive in 28.6% of serotonin-secreting PNETs (one with carcinoid syndrome) and negative in all controls. Carcinoid syndrome is rare in patients with a PNET, but serotonin secretion occurs often. This is a negative prognostic factor for OS, but after correction for CgA and NSE, it is no longer a predictor and probably only a "not-so innocent bystander" in patients with high tumour burden. © 2017 John Wiley & Sons Ltd.

Apolipoprotein A-V is present in bile and its secretion increases with lipid absorption in Sprague-Dawley rats.

PubMed

Zhang, Linda S; Sato, Hirokazu; Yang, Qing; Ryan, Robert O; Wang, David Q-H; Howles, Philip N; Tso, Patrick

2015-12-01

Apolipoprotein (apo) A-V is a protein synthesized only in the liver that dramatically modulates plasma triglyceride levels. Recent studies suggest a novel role for hepatic apoA-V in regulating the absorption of dietary triglycerides, but its mode of action on the gut remains unknown. The aim of this study was to test for apoA-V in bile and to determine whether its secretion is regulated by dietary lipids. After an overnight recovery, adult male Sprague-Dawley bile fistula rats indeed secreted apoA-V into bile at a constant rate under fasting conditions. An intraduodenal bolus of intralipid (n = 12) increased the biliary secretion of apoA-V but not of other apolipoproteins, such as A-I, A-IV, B, and E. The lipid-induced increase of biliary apoA-V was abolished under conditions of poor lymphatic lipid transport, suggesting that the stimulation is regulated by the magnitude of lipids associated with chylomicrons transported into lymph. We also studied the secretion of apoA-V into bile immediately following bile duct cannulation. Biliary apoA-V increased over time (∼6-fold increase at hour 16, n = 8) but the secretions of other apolipoproteins remained constant. Replenishing luminal phosphatidylcholine and taurocholate (n = 9) only enhanced apoA-V secretion in bile, suggesting that the increase was not due to depletion of phospholipids or bile salts. This is the first study to demonstrate that apoA-V is secreted into bile, introducing a potential route of delivery of hepatic apoA-V to the gut lumen. Our study also reveals the uniqueness of apoA-V secretion into bile that is regulated by mechanisms different from other apolipoproteins. Copyright © 2015 the American Physiological Society.

Apolipoprotein A-V is present in bile and its secretion increases with lipid absorption in Sprague-Dawley rats

PubMed Central

Sato, Hirokazu; Yang, Qing; Ryan, Robert O.; Wang, David Q.-H.; Howles, Philip N.; Tso, Patrick

2015-01-01

Apolipoprotein (apo) A-V is a protein synthesized only in the liver that dramatically modulates plasma triglyceride levels. Recent studies suggest a novel role for hepatic apoA-V in regulating the absorption of dietary triglycerides, but its mode of action on the gut remains unknown. The aim of this study was to test for apoA-V in bile and to determine whether its secretion is regulated by dietary lipids. After an overnight recovery, adult male Sprague-Dawley bile fistula rats indeed secreted apoA-V into bile at a constant rate under fasting conditions. An intraduodenal bolus of intralipid (n = 12) increased the biliary secretion of apoA-V but not of other apolipoproteins, such as A-I, A-IV, B, and E. The lipid-induced increase of biliary apoA-V was abolished under conditions of poor lymphatic lipid transport, suggesting that the stimulation is regulated by the magnitude of lipids associated with chylomicrons transported into lymph. We also studied the secretion of apoA-V into bile immediately following bile duct cannulation. Biliary apoA-V increased over time (∼6-fold increase at hour 16, n = 8) but the secretions of other apolipoproteins remained constant. Replenishing luminal phosphatidylcholine and taurocholate (n = 9) only enhanced apoA-V secretion in bile, suggesting that the increase was not due to depletion of phospholipids or bile salts. This is the first study to demonstrate that apoA-V is secreted into bile, introducing a potential route of delivery of hepatic apoA-V to the gut lumen. Our study also reveals the uniqueness of apoA-V secretion into bile that is regulated by mechanisms different from other apolipoproteins. PMID:26505974

Growth hormone secretory pattern and response to treatment in children with short stature followed to adult height.

PubMed

Radetti, Giorgio; Buzi, Fabio; Cassar, Walburga; Paganini, Claudio; Stacul, Elisabetta; Maghnie, Mohamad

2003-07-01

To compare the relative utility of GH stimulation tests and assays of spontaneous GH secretion as predictors of change in height standard deviation score at the end of GH treatment in children with short stature. We retrospectively studied 116 children (67 boys and 49 girls) with subnormal growth rates and short stature, defined as a height of more than 2SD below the mean for age and sex. The patients were classified according to their pattern of findings on baseline pharmacological GH stimulation tests and a 12-h assay of nocturnal spontaneous GH secretion. Twenty-eight patients (24%) had normal hormone levels by both methods (group I); 14 (12%) had normal levels by stimulation tests but subnormal levels by the physiological assay (group II); 48 (41%) had subnormal levels on pharmacological stimulation, with normal physiologic levels (group III); and 26 (22%) had subnormal levels by both methods (group IV). All children in groups II and IV, and 27 in group III, designated IIIb, were treated with recombinant GH at 0.7 U (0.23 mg/kg) of body weight per week. GH secretory patterns were related to final height SD scores and other growth parameters, after the patients had attained their adult stature 6.7 +/- 2.2 years (SD) after GH evaluation. The five groups were similar with respect to mean baseline height SD scores for chronological as well as bone age. Whether assessed as absolute or parentally adjusted (relative) values, mean gains in height SD scores were significantly greater in treated patients with physiological hormone deficiency (groups II and IV) than in those with normal hormone levels (group I, untreated controls). Relative height gains were 1.03 +/- 1.45 cm (6.6 +/- 9.28 cm) and 1.85 +/- 1.21 cm (SDS; 11.8 +/- 7.74 cm) in groups II and IV respectively, compared with only 0.11 +/- 0.42 cm (0.7 +/- 2.68 cm) in group I (P < 0.01 and P < 0.001). GH treatment failed to improve either the absolute or parentally adjusted final height of patients with GH deficiency by stimulation tests but normal levels by physiological assay. Long-term administration of GH to short children with normal spontaneous GH secretion is not associated with an appreciable increase in adult height.

Apolipoprotein E4 (1-272) fragment is associated with mitochondrial proteins and affects mitochondrial function in neuronal cells.

PubMed

Nakamura, Toshiyuki; Watanabe, Atsushi; Fujino, Takahiro; Hosono, Takashi; Michikawa, Makoto

2009-08-20

Apolipoprotein E allele epsilon4 (apoE4) is a strong risk factor for developing Alzheimer's disease (AD). Secreted apoE has a critical function in redistributing lipids among central nervous system cells to maintain normal lipid homeostasis. In addition, previous reports have shown that apoE4 is cleaved by a protease in neurons to generate apoE4(1-272) fragment, which is associated with neurofibrillary tanglelike structures and mitochondria, causing mitochondrial dysfunction. However, it still remains unclear how the apoE fragment associates with mitochondria and induces mitochondrial dysfunction. To clarify the molecular mechanism, we carried out experiments to identify intracellular apoE-binding molecules and their functions in modulating mitochondria function. Here, we found that apoE4 binds to ubiquinol cytochrome c reductase core protein 2 (UQCRC2) and cytochrome C1, both of which are components of mitochondrial respiratory complex III, and cytochrome c oxidase subunit 4 isoform 1 (COX IV 1), which is a component of complex IV, in Neuro-2a cells. Interestingly, these proteins associated with apoE4(1-272) more strongly than intact apoE4(1-299). Further analysis showed that in Neuro-2a cells expressing apoE4(1-272), the enzymatic activities of mitochondrial respiratory complexes III and IV were significantly lower than those in Neuro-2a cells expressing apoE4(1-299). ApoE4(1-272) fragment expressed in Neuro2a cells is associated with mitochondrial proteins, UQCRC2 and cytochrome C1, which are component of respiratory complex III, and with COX IV 1, which is a member of complex IV. Overexpression of apoE4(1-272) fragment impairs activities of complex III and IV. These results suggest that the C-terminal-truncated fragment of apoE4 binds to mitochondrial complexes and affects their activities, and thereby leading to neurodegeneration.

Transfer of the α5(IV) Collagen Chain Gene to Smooth Muscle Restores in Vivo Expression of the α6(IV) Collagen Chain in a Canine Model of Alport Syndrome

PubMed Central

Harvey, Scott J.; Zheng, Keqin; Jefferson, Barbara; Moak, Peter; Sado, Yoshikazu; Naito, Ichiro; Ninomiya, Yoshifumi; Jacobs, Robert; Thorner, Paul S.

2003-01-01

X-linked Alport syndrome is a progressive renal disease caused by mutations in the COL4A5 gene, which encodes the α5(IV) collagen chain. As an initial step toward gene therapy for Alport syndrome, we report on the expression of recombinant α5(IV) collagen in vitro and in vivo. A full-length cDNA-encoding canine α5(IV) collagen was cloned and expressed in vitro by transfection of HEK293 cells that synthesize the α1(IV) and α2(IV), but not the α3(IV) to α6(IV) collagen chains. By Northern blotting, an α5(IV) mRNA transcript of 5.2 kb was expressed and the recombinant protein was detected by immunocytochemistry. The chain was secreted into the medium as a 190-kd monomer; no triple helical species were detected. Transfected cells synthesized an extracellular matrix containing the α1(IV) and α2(IV) chains but the recombinant α5(IV) chain was not incorporated. These findings are consistent with the concept that the α5(IV) chain requires one or more of the α3(IV), α4(IV), or α6(IV) chains for triple helical assembly. In vivo studies were performed in dogs with X-linked Alport syndrome. An adenoviral vector containing the α5(IV) transgene was injected into bladder smooth muscle that lacks both the α5(IV) and α6(IV) chains in these animals. At 5 weeks after injection, there was expression of both the α5(IV) and α6(IV) chains by smooth muscle cells at the injection site in a basement membrane distribution. Thus, this recombinant α5(IV) chain is capable of restoring expression of a second α(IV) chain that requires the presence of the α5(IV) chain for incorporation into collagen trimers. This vector will serve as a useful tool to further explore gene therapy for Alport syndrome. PMID:12598321

Perlecan Domain V Induces VEGf Secretion in Brain Endothelial Cells through Integrin α5β1 and ERK-Dependent Signaling Pathways

PubMed Central

Clarke, Douglas N.; Al Ahmad, Abraham; Lee, Boyeon; Parham, Christi; Auckland, Lisa; Fertala, Andrezj; Kahle, Michael; Shaw, Courtney S.; Roberts, Jill; Bix, Gregory J.

2012-01-01

Perlecan Domain V (DV) promotes brain angiogenesis by inducing VEGF release from brain endothelial cells (BECs) following stroke. In this study, we define the specific mechanism of DV interaction with the α5β1 integrin, identify the downstream signal transduction pathway, and further investigate the functional significance of resultant VEGF release. Interestingly, we found that the LG3 portion of DV, which has been suggested to possess most of DV’s angio-modulatory activity outside of the brain, binds poorly to α5β1 and induces less BEC proliferation compared to full length DV. Additionally, we implicate DV’s DGR sequence as an important element for the interaction of DV with α5β1. Furthermore, we investigated the importance of AKT and ERK signaling in DV-induced VEGF expression and secretion. We show that DV increases the phosphorylation of ERK, which leads to subsequent activation and stabilization of eIF4E and HIF-1α. Inhibition of ERK activity by U0126 suppressed DV-induced expression and secretion of VEGR in BECs. While DV was capable of phosphorylating AKT we show that AKT phosphorylation does not play a role in DV’s induction of VEGF expression or secretion using two separate inhibitors, LY294002 and Akt IV. Lastly, we demonstrate that VEGF activity is critical for DV increases in BEC proliferation, as well as angiogenesis in a BEC-neuronal co-culture system. Collectively, our findings expand our understanding of DV’s mechanism of action on BECs, and further support its potential as a novel stroke therapy. PMID:23028886

Insulin and GH secretion in adolescent girls with irregular cycles: polycystic vs multifollicular ovaries.

PubMed

Villa, P; Rossodivita, A; Fulghesu, A M; Cucinelli, F; Barini, A; Apa, R; Belosi, C; Lanzone, A

2003-04-01

In the present study insulin (I) and GH secretion was studied in a group of twenty-five young adolescent girls (mean age: 15 +/- 0.23 yr) with cycle irregularity associated to clinical signs of hyperandrogenism in comparison with that observed in eleven normal matched subjects with regular menses. All patients underwent basal hormone measurements and, on two consecutive days, an oral glucose tolerance test (OGTT) and a GHRH iv test. Therefore, all subjects had a transabdominal US scan for the measurement of ovarian volume and the characterization of ovarian morphology. On the basis of the US examination we found patients with polycystic ovaries (PCO-like group) and subjects with multifollicular ovaries (MFO group). PCO-like group exhibited T (p<0.01) and LH (p<0.05) plasma levels higher than control group and the highest free androgen index (FAI) values (13 +/- 0.87). All patients with irregular menses showed plasma concentrations of AUC for I (AUC-I) significantly higher in respect to control group (7359.4 +/- 709 vs 5447 +/- 431 microIU/ml x 180 min, p<0.01) as well as both PCO-like group and MFO group did (p<0.001 and p<0.01) respectively. MFO group showed higher values of the AUC for GH (AUC-GH) (2809 +/- 432 ng/ml x 120 min) in respect to controls (1708 +/- 208 ng/ml x 120 min, p<0.05) and PCO-like subjects (p<0.001), who on the contrary showed the lowest AUC-GH values (618 +/- 119 ng/ml x 120 min). In conclusion, PCO-like patients associated hyperinsulinemia with a blunted GH secretion while MFO patients had higher GH secretion associated with higher AUC-I values in a way suggesting an immature and still developing reproductive system.

Effect of bismuth subcitrate and sucralfate on rat duodenal and human gastric bicarbonate secretion in vivo.

PubMed Central

Shorrock, C J; Garner, A; Hunter, A H; Crampton, J R; Rees, W D

1990-01-01

Acid and alkali secretion have been examined together with prostaglandin E2 production in response to two mucosal protective drugs, colloidal bismuth subcitrate and sucralfate. Doses of colloidal bismuth subcitrate in the therapeutic range (120 and 1200 mg) had no effect on alkali secretion or luminal PGE2 output when perfused into the stomach of human volunteers. Similarly, in the anaesthetised rat, neither gastric acid nor duodenal alkali secretions were influenced by iv (12 mg/kg) or topical (120 mg/ml) administration of colloidal bismuth subcitrate. In contrast, perfusion of the human stomach with 1 g sucralfate stimulated bicarbonate output by 50%, a response which was unaffected by indomethacin (25 mg/h). A rise of 64% in gastric PGE2 output after sucralfate was, however, prevented by indomethacin pretreatment. Alkali secretion by rat duodenum was also increased by sucralfate but the response depended on the basal secretory rate. Low basal secretors (less than 3 mumol) showed a 75% stimulation whereas rats with high basal secretory rates (greater than 3 mumol) showed no significant response. All duodenal preparations regardless of basal secretory rate showed a stimulation of bicarbonate output with topical PGE2. The results suggest that enhancement of gastroduodenal bicarbonate secretion may play a role in the protective action of sucralfate but is unlikely to explain mucosal protection by colloidal bismuth subcitrate. PMID:2318428

The time course of follicle-stimulating hormone suppression by recombinant human inhibin A in the adult male rhesus monkey (Macaca mulatta).

PubMed

Ramaswamy, S; Pohl, C R; McNeilly, A S; Winters, S J; Plant, T M

1998-08-01

In higher primates, FSH secretion appears to be regulated by a control system consistent with that described by the classical inhibin hypothesis. The purpose of the present experiment was to examine the time course of inhibin's action to suppress FSH secretion in the intact adult male rhesus monkey. To this end, five adult males implanted with indwelling venous catheters and exhibiting typical episodic patterns of LH and testosterone (T) secretion received a 4-day i.v. infusion of recombinant human (rh) inhibin A (832 ng/h x kg) followed, after a 4-week interval, by vehicle infusion of similar duration. Changes in circulating FSH concentrations during the inhibin and vehicle infusions were determined using a sensitive homologous macaque RIA, whereas enzyme-linked immunosorbent assays were employed to track inhibin A, inhibin B, and inhibin pro-alpha-C levels during the experiment. Normal pulsatile activity in the hypothalamic-pituitary-Leydig cell axis was confirmed by monitoring changes in circulating concentrations of LH and T in 12-h windows of sequential blood collection (1200-2400 h; every 20 min) before, during, and after the rh inhibin A and vehicle infusions. Although infusion of rh inhibin A, which led to a 12 ng/ml square wave increment in circulating levels of this inhibin dimer, produced a marked decline in circulating FSH concentrations, significant suppression of the secretion of this gonadotropin was not manifest until 54 h after initiation of the infusion. Despite the marked decline in FSH secretion during the last 24 h of the 4-day infusion of recombinant hormone, circulating inhibin B and pro-alpha-C concentrations were maintained at preinfusion control levels (1 ng/ml). The finding that imposition of an exaggerated circulating inhibin signal led to suppression of FSH secretion in the male monkey only after 2 days of exposure to the hormone indicates that in this species the feedback action of testicular inhibin on FSH secretion is heavily lagged. Moreover, as the decrease in FSH did not lead to changes in native inhibin secretion, it seems reasonable to propose that the FSH-inhibin feedback loop that governs testicular function in higher primates operates with considerable hysteresis at both the pituitary and gonadal levels. The failure of dramatically elevated inhibin A levels to influence the pulsatile secretion of LH in the monkey reinforces the idea that in this species the pituitary action of testicular inhibin is specific for FSH and does not involve modulation of GnRH receptor levels.

Type IV Secretion and Signal Transduction of Helicobacter pylori CagA through Interactions with Host Cell Receptors

PubMed Central

Backert, Steffen; Tegtmeyer, Nicole

2017-01-01

Helicobacter pylori is a highly successful human bacterium, which is exceptionally equipped to persistently inhabit the human stomach. Colonization by this pathogen is associated with gastric disorders ranging from chronic gastritis and peptic ulcers to cancer. Highly virulent H. pylori strains express the well-established adhesins BabA/B, SabA, AlpA/B, OipA, and HopQ, and a type IV secretion system (T4SS) encoded by the cag pathogenicity island (PAI). The adhesins ascertain intimate bacterial contact to gastric epithelial cells, while the T4SS represents an extracellular pilus-like structure for the translocation of the effector protein CagA. Numerous T4SS components including CagI, CagL, CagY, and CagA have been shown to target the integrin-β1 receptor followed by translocation of CagA across the host cell membrane. The interaction of CagA with membrane-anchored phosphatidylserine and CagA-containing outer membrane vesicles may also play a role in the delivery process. Translocated CagA undergoes tyrosine phosphorylation in C-terminal EPIYA-repeat motifs by oncogenic Src and Abl kinases. CagA then interacts with an array of host signaling proteins followed by their activation or inactivation in phosphorylation-dependent and phosphorylation-independent fashions. We now count about 25 host cell binding partners of intracellular CagA, which represent the highest quantity of all currently known virulence-associated effector proteins in the microbial world. Here we review the research progress in characterizing interactions of CagA with multiple host cell receptors in the gastric epithelium, including integrin-β1, EGFR, c-Met, CD44, E-cadherin, and gp130. The contribution of these interactions to H. pylori colonization, signal transduction, and gastric pathogenesis is discussed. PMID:28338646

Differential interactions of virulent and non-virulent H. parasuis strains with naïve or swine influenza virus pre-infected dendritic cells

PubMed Central

2012-01-01

Pigs possess a microbiota in the upper respiratory tract that includes Haemophilus parasuis. Pigs are also considered the reservoir of influenza viruses and infection with this virus commonly results in increased impact of bacterial infections, including those by H. parasuis. However, the mechanisms involved in host innate responses towards H. parasuis and their implications in a co-infection with influenza virus are unknown. Therefore, the ability of a non-virulent H. parasuis serovar 3 (SW114) and a virulent serovar 5 (Nagasaki) strains to interact with porcine bone marrow dendritic cells (poBMDC) and their modulation in a co-infection with swine influenza virus (SwIV) H3N2 was examined. At 1 hour post infection (hpi), SW114 interaction with poBMDC was higher than that of Nagasaki, while at 8 hpi both strains showed similar levels of interaction. The co-infection with H3N2 SwIV and either SW114 or Nagasaki induced higher levels of IL-1β, TNF-α, IL-6, IL-12 and IL-10 compared to mock or H3N2 SwIV infection alone. Moreover, IL-12 and IFN-α secretion differentially increased in cells co-infected with H3N2 SwIV and Nagasaki. These results pave the way for understanding the differences in the interaction of non-virulent and virulent strains of H. parasuis with the swine immune system and their modulation in a viral co-infection. PMID:23157617

Pharmacological properties of 2-(2-chloro-p-toluidino)-2-imidazoline-nitrate (tolonidine), a new antihypertensive agent. III. Action on the secretions of the digestive tract and on the central nervous system, acute toxicity.

PubMed

Cosnier, D; Hache, J; Labrid, C; Streichenberger, G

1975-01-01

The pharmacological properties of 2-(2-chloro-p-toluidino)-2-imidazoline-nitrate (tolonidine) a new synthetic derivative of imidazoline are reported in a series of three successive articles. This compound has been shown to possess hypotensive and antihypertensive properties. After i.v. administration, the hypotensive phase was preceded by hypertension related to the potent direct alpha-sympatheticomimetic properties of the product. This pressor response, which was not seen after oral administration, was accompanied by a marked decrease in cardiac output and a significant increase in peripheral vascular resistance. The hypotensive action of the product was due to a drop in cardiac output probably reinforced by a decrease in vasoconstrictor sympathetic tone due to a central action. Whatever the route of administration, tolonidine slowed heart rate independently of blood pressure variations, due essentially to an increase in vagal tone. In studies of diuresis, liquid and salt loss were observed in the cat, not in the dog. At doses which induce a drop in blood pressure tolonidine did not produce a reduction in pilocarpine-induced salivary secretion and only partially inhibited gastric secretion. In the central nervous system, tolonidine produced a sedation which first appeared at doses having an antihypertensive effect but which was only fully apparent with increased doses. A decrease in the release of cerebral amines, serotonin and noradrenaline by tolonidine is proposed. Tolonidine was compared with three other antihypertensive agents: clonidine, which is structurally related, and guanethidine and mecamylamine, which are structurally unrelated and have a different mode of action. A close resemblance of the pharmacological properties of tolonidine and clonidine was established due to the chemical relationship between the two substances.

Competition between conjugation and M13 phage infection in Escherichia coli in the absence of selection pressure: a kinetic study.

PubMed

Wan, Zhenmao; Goddard, Noel L

2012-10-01

Inter- and intraspecies horizontal gene transfer enabled by bacterial secretion systems is a powerful mechanism for bacterial genome plasticity. The type IV secretion system of Escherichia coli, encoded by the F plasmid, enables cell-to-cell contact and subsequent DNA transfer known as conjugation. Conjugation is compromised by phage infection that specifically targets the secretion machinery. Hence, the use of phages to regulate the spread of genes, such as acquired antibiotic resistance or as general biosanitation agents, has gained interest. To predict the potential efficacy, the competition kinetics must first be understood. Using quantitative PCR to enumerate genomic loci in a resource-limited batch culture, we quantify the infection kinetics of the nonlytic phage M13 and its impact on conjugation in the absence of selection pressure (isogenic set). Modeling the resulting experimental data reveals the cellular growth rate to be reduced to 60% upon phage infection. We also find a maximum phage infection rate of 3×10(-11) mL phage(-1) min(-1) which is only 1 order of magnitude slower than the maximum conjugation rate (3×10(-10) mL cell(-1) min(-1)), suggesting phages must be in significant abundance to be effective antagonists to horizontal gene transfer. In the regime where the number of susceptible cells (F(+)) and phages are equal upon initial infection, we observe the spread of the conjugative plasmid throughout the cell population despite phage infection, but only at 10% of the uninfected rate. This has interesting evolutionary implications, as even in the absence of selection pressure, cells maintain the ability to conjugate despite phage vulnerability and the associated growth consequences.

Sympathetic activity in patients with panic disorder at rest, under laboratory mental stress, and during panic attacks.

PubMed

Wilkinson, D J; Thompson, J M; Lambert, G W; Jennings, G L; Schwarz, R G; Jefferys, D; Turner, A G; Esler, M D

1998-06-01

The sympathetic nervous system has long been believed to be involved in the pathogenesis of panic disorder, but studies to date, most using peripheral venous catecholamine measurements, have yielded conflicting and equivocal results. We tested sympathetic nervous function in patients with panic disorder by using more sensitive methods. Sympathetic nervous and adrenal medullary function was measured by using direct nerve recording (clinical microneurography) and whole-body and cardiac catecholamine kinetics in 13 patients with panic disorder as defined by the DSM-IV, and 14 healthy control subjects. Measurements were made at rest, during laboratory stress (forced mental arithmetic), and, for 4 patients, during panic attacks occurring spontaneously in the laboratory setting. Muscle sympathetic activity, arterial plasma concentration of norepinephrine, and the total and cardiac norepinephrine spillover rates to plasma were similar in patients and control subjects at rest, as was whole-body epinephrine secretion. Epinephrine spillover from the heart was elevated in patients with panic disorder (P=.01). Responses to laboratory mental stress were almost identical in patient and control groups. During panic attacks, there were marked increases in epinephrine secretion and large increases in the sympathetic activity in muscle in 2 patients but smaller changes in the total norepinephrine spillover to plasma. Whole-body and regional sympathetic nervous activity are not elevated at rest in patients with panic disorder. Epinephrine is released from the heart at rest in patients with panic disorder, possibly due to loading of cardiac neuronal stores by uptake from plasma during surges of epinephrine secretion in panic attacks. Contrary to popular belief, the sympathetic nervous system is not globally activated during panic attacks.

An investigation into the relative merits of pituitary adenylate cyclase-activating polypeptide (PACAP-27) and vasoactive intestinal polypeptide as vagal neuro-transmitters in exocrine pancreas of rats.

PubMed

Wheeler, S; Eardley, J E; McNulty, K F; Sutcliffe, C P; Morrison, J D

1997-07-01

Pancreatic exocrine secretions were collected over 15 min periods and analysed in terms of weight of juice, total HCO3- and total protein in anaesthetized and pithed rats. Pituitary adenylate cyclase-activating polypeptide (PACAP) (i.v.) evoked a serous HCO3- secretion which contained relatively little protein, together with a marked vasodepressor action. The latter was still maximal at lower doses of PACAP, which evoked diminished pancreatic secretions. The effects of PACAP were similar to those evoked by the same dose of VIP and by cervical vagal stimulation, while secretion evoked a much larger secretion of fluid and HCO3-. The time courses of the PACAP-evoked secretions were significantly delayed compared with those of VIP. In the pithed rat, PACAP caused the same level of pancreatic secretions as in the anaesthetized rat, though this was now accompanied by a substantial pressor response which was blocked by phentolamine or prazosin, indicating that it was alpha 1-adrenoceptor mediated. VIP caused a depressor response in the pithed rat, as well as the same level of pancreatic secretions as in the anaesthetized rat. The putative VIP antagonist [Lys1,Pro25,Arg3,4,Tyr6]-VIP (abbreviated as VIPi) caused a selective and significant reduction in the HCO3- secretion evoked by VIP and blocked the vasodepressor response caused by VIP. By contrast, VIPi did not antagonize either the secretory or vasodepressor actions of PACAP. Unilateral electrical stimulation of the cervical vagus nerve evoked significant increases in the weight of juice, total protein and total HCO3- secreted. When preceded by injection of VIPi, vagally evoked secretions were unchanged in terms of weight of juice and total protein but had a significantly reduced HCO3- content. These results are consistent with the release of VIP, though not PACAP, as a vagal neurotransmitter in the exocrine pancreas.

Mucinous (colloid) adenocarcinomas secrete distinct O-acylated forms of sialomucins: a histochemical study of gastric, colorectal and breast adenocarcinomas.

PubMed

Sáez, C; Japón, M A; Poveda, M A; Segura, D I

2001-12-01

Mucinous (colloid) adenocarcinomas represent a distinct group of tumours defined by the presence of large amounts of extracellular mucins. By using histochemical methods, we analysed mucins secreted by mucinous versus non-mucinous adenocarcinomas and looked for differential secretion profiles. Sixty-four adenocarcinomas were studied (23 colorectal, 17 gastric, and 24 breast tumours). Thirty-two tumours were of the colloid type. The following methods were applied to paraffin tissue sections: (i) Alcian blue (pH 2.5) and periodic acid-Schiff (PAS); (ii) high iron diamine and Alcian blue (pH 2.5); (iii) periodic acid borohydride, potassium hydroxide, and PAS; (iv) periodic acid-thionine Schiff, potassium hydroxide, and PAS; and (v) periodic acid-borohydride and PAS. Most adenocarcinomas secreted acidic mucins, with sialomucins predominating over sulfomucins, except for non-mucinous adenocarcinomas of the breast which showed predominant neutral mucins. All mucinous adenocarcinomas contained C9-O-acyl sialic acid as mono, di(C8,C9)-, or tri(C7,C8,C9)-O-acyl forms. Acidic mucins secreted by the majority of non-colloid adenocarcinomas consisted of non-O-acylated sialomucins. C9-O-acylation of sialic acid is a characteristic feature of mucinous adenocarcinomas and can be readily detected by histochemical methods.

Differences in beta-cell function and insulin secretion in Black vs. White obese adolescents: Do incretin hormones play a role?

USDA-ARS?s Scientific Manuscript database

Black youth are at higher risk for type 2 diabetes (T2D) than their White peers. Previously we demonstrated that for the same degree of insulin sensitivity, Black youth have an upregulated beta-cell function and insulin hypersecretion, in response to intravenous (IV) glucose, compared with Whites. T...

Modulation of host cell function by Legionella pneumophila type IV effectors.

PubMed

Hubber, Andree; Roy, Craig R

2010-01-01

Macrophages and protozoa ingest bacteria by phagocytosis and destroy these microbes using a conserved pathway that mediates fusion of the phagosome with lysosomes. To survive within phagocytic host cells, bacterial pathogens have evolved a variety of strategies to avoid fusion with lysosomes. A virulence strategy used by the intracellular pathogen Legionella pneumophila is to manipulate host cellular processes using bacterial proteins that are delivered into the cytosolic compartment of the host cell by a specialized secretion system called Dot/Icm. The proteins delivered by the Dot/Icm system target host factors that play evolutionarily conserved roles in controlling membrane transport in eukaryotic cells, which enables L. pneumophila to create an endoplasmic reticulum-like vacuole that supports intracellular replication in both protozoan and mammalian host cells. This review focuses on intracellular trafficking of L. pneumophila and describes how bacterial proteins contribute to modulation of host processes required for survival within host cells.

Type IV secretion system of Brucella spp. and its effectors

PubMed Central

Ke, Yuehua; Wang, Yufei; Li, Wengfeng; Chen, Zeliang

2015-01-01

Brucella spp. are intracellular bacterial pathogens that cause infection in domestic and wild animals. They are often used as model organisms to study intracellular bacterial infections. Brucella VirB T4SS is a key virulence factor that plays important roles in mediating intracellular survival and manipulating host immune response to infection. In this review, we discuss the roles of Brucella VirB T4SS and 15 effectors that are proposed to be crucial for Brucella pathogenesis. VirB T4SS regulates the inflammation response and manipulates vesicle trafficking inside host cells. VirB T4SS also plays crucial roles in the inhibition of the host immune response and intracellular survival during infection. Here, we list the key molecular events in the intracellular life cycle of Brucella that are potentially targeted by the VirB T4SS effectors. Elucidating the functions of these effectors will help clarify the molecular role of T4SS during infection. Furthermore, studying the effectors secreted by Brucella spp. might provide insights into the mechanisms used by the bacteria to hijack the host signaling pathways and aid in the development of better vaccines and therapies against brucellosis. PMID:26528442

Type IV secretion system of Brucella spp. and its effectors.

PubMed

Ke, Yuehua; Wang, Yufei; Li, Wengfeng; Chen, Zeliang

2015-01-01

Brucella spp. are intracellular bacterial pathogens that cause infection in domestic and wild animals. They are often used as model organisms to study intracellular bacterial infections. Brucella VirB T4SS is a key virulence factor that plays important roles in mediating intracellular survival and manipulating host immune response to infection. In this review, we discuss the roles of Brucella VirB T4SS and 15 effectors that are proposed to be crucial for Brucella pathogenesis. VirB T4SS regulates the inflammation response and manipulates vesicle trafficking inside host cells. VirB T4SS also plays crucial roles in the inhibition of the host immune response and intracellular survival during infection. Here, we list the key molecular events in the intracellular life cycle of Brucella that are potentially targeted by the VirB T4SS effectors. Elucidating the functions of these effectors will help clarify the molecular role of T4SS during infection. Furthermore, studying the effectors secreted by Brucella spp. might provide insights into the mechanisms used by the bacteria to hijack the host signaling pathways and aid in the development of better vaccines and therapies against brucellosis.

DBSecSys: a database of Burkholderia mallei secretion systems.

PubMed

Memišević, Vesna; Kumar, Kamal; Cheng, Li; Zavaljevski, Nela; DeShazer, David; Wallqvist, Anders; Reifman, Jaques

2014-07-16

Bacterial pathogenicity represents a major public health concern worldwide. Secretion systems are a key component of bacterial pathogenicity, as they provide the means for bacterial proteins to penetrate host-cell membranes and insert themselves directly into the host cells' cytosol. Burkholderia mallei is a Gram-negative bacterium that uses multiple secretion systems during its host infection life cycle. To date, the identities of secretion system proteins for B. mallei are not well known, and their pathogenic mechanisms of action and host factors are largely uncharacterized. We present the Database of Burkholderia malleiSecretion Systems (DBSecSys), a compilation of manually curated and computationally predicted bacterial secretion system proteins and their host factors. Currently, DBSecSys contains comprehensive experimentally and computationally derived information about B. mallei strain ATCC 23344. The database includes 143 B. mallei proteins associated with five secretion systems, their 1,635 human and murine interacting targets, and the corresponding 2,400 host-B. mallei interactions. The database also includes information about 10 pathogenic mechanisms of action for B. mallei secretion system proteins inferred from the available literature. Additionally, DBSecSys provides details about 42 virulence attenuation experiments for 27 B. mallei secretion system proteins. Users interact with DBSecSys through a Web interface that allows for data browsing, querying, visualizing, and downloading. DBSecSys provides a comprehensive, systematically organized resource of experimental and computational data associated with B. mallei secretion systems. It provides the unique ability to study secretion systems not only through characterization of their corresponding pathogen proteins, but also through characterization of their host-interacting partners.The database is available at https://applications.bhsai.org/dbsecsys.

Protist-Bacteria Associations: Gammaproteobacteria and Alphaproteobacteria Are Prevalent as Digestion-Resistant Bacteria in Ciliated Protozoa

PubMed Central

Gong, Jun; Qing, Yao; Zou, Songbao; Fu, Rao; Su, Lei; Zhang, Xiaoli; Zhang, Qianqian

2016-01-01

Protistan bacterivory, a microbial process involving ingestion and digestion, is ecologically important in the microbial loop in aquatic and terrestrial ecosystems. While bacterial resistance to protistan ingestion has been relatively well understood, little is known about protistan digestion in which some ingested bacteria could not be digested in cells of major protistan grazers in the natural environment. Here we report the phylogenetic identities of digestion-resistant bacteria (DRB) that could survive starvation and form relatively stable associations with 11 marine and one freshwater ciliate species. Using clone library and sequencing of 16S rRNA genes, we found that the protistan predators could host a high diversity of DRB, most of which represented novel bacterial taxa that have not been cultivated. The localization inside host cells, quantity, and viability of these bacteria were checked using fluorescence in situ hybridization. The DRB were affiliated with Actinobacteria, Bacteroidetes, Firmicutes, Parcubacteria (OD1), Planctomycetes, and Proteobacteria, with Gammaproteobacteria and Alphaproteobacteria being the most frequently occurring classes. The dominance of Gamma- and Alphaproteobacteria corresponds well to a previous study of Global Ocean Sampling metagenomic data showing the widespread types of bacterial type VI and IV secretion systems (T6SS and T4SS) in these two taxa, suggesting a putatively significant role of secretion systems in promoting marine protist-bacteria associations. In the DRB assemblages, opportunistic bacteria such as Alteromonadaceae, Pseudoalteromonadaceae, and Vibrionaceae often presented with high proportions, indicating these bacteria could evade protistan grazing thus persist and accumulate in the community, which, however, contrasts with their well-known rarity in nature. This begs the question whether viral lysis is significant in killing these indigestible bacteria in microbial communities. Taken together, our study on the identity of DRB sheds new light on microbial interactions and generates further hypotheses including the potential importance of bacterial protein secretion systems in structuring bacterial community composition and functioning of “microbial black box” in aquatic environments. PMID:27148188

Bile salt induced back diffusion of hydrogen ions across gastric mucosa in man. Fact or fiction?

PubMed

Ivey, K J

1981-01-01

We studied the effect of 5.5 mM bile salts, consisting of taurine conjugates in 5 normal subjects. Bile salts caused a significant increase in H+ loss from and Na+ movement into the gastric lumen (controls 1.5 mEq H+, 1.5 mEq Na+; bile salts -3.1 mEq H+ (p less than 0.001), Na+ 2.5 mEq (p less than 0.01) per 15 min.) To determine the effect of acid secretion, studies were repeated after i.v. atropine 2 mg/70 kg b.w. Atropine reduced net H+ flux to -0.2 mEq and Na+ gain to 0.9 mEq. When the bile salt studies were repeated after i.v. atropine, net H+ loss was increased to -5.4 mEq H+, significantly greater than with bile salts alone; corresponding Na+ gain was 3.2 mEq/15 min. The volume of fluid secreted was 25.0 ml in the bile salt study compared with 14.0 ml in the atropine and bile salt study. Even if all the additional volume 'secreted' (14 ml) were bicarbonate from the stomach or pancreatic juice with a concentration of 145 mEq/liter, it could account for a loss of only 2.0 mEq H+. In conclusion, atropine with bile salts is associated with a loss of H+ ions too great to be accounted for by bicarbonate neutralization. We conclude that back diffusion of H+ ions is the most likely explanation of H+ loss after bile salts in man.

Renal creatinine handling in very old patients with chronic renal disease.

PubMed

Musso, Carlos G; Michelángelo, Hernán; Vilas, Manuel; Martinez, Bernardo; Bonetto, Alberto; Jauregui, Ricardo; Algranati, Luis

2011-09-01

Renal creatinine handling is basically the result of its glomerular filtration and proximal tubular secretion. However, creatinine reabsorption has been documented in certain conditions, such as premature babies, newborns, and healthy elderly people. Additionally, it is known that there is an increase in the proportion of secreted creatinine in chronic renal disease. In this paper, we report our studies on the characteristic reabsorption pattern of creatinine in the elderly with chronic renal disease. We studied twenty-seven volunteers with chronic kidney disease, eleven of whom were young and the rest were very old (age > 75 years old). We measured creatinine clearance without (Ccr) and with cimetidine (CcrWC) and Ccr/CcrWC ratio from each volunteer, in timed urine samples. Then, Ccr, CcrWC, and Ccr/CcrWC ratio were compared between young and very old people in two chronic kidney disease subgroups: stages II-III and stages IV-V. Statistical analysis was performed applying a non-parametric test (Wilcoxon). We observed a tendency towards a lower Ccr/CcrWC ratio in the very old stage II-III group compared with the young one: 1 (0.96-1.26) (very old) vs 1.3 (1.1-1.5) (young), P = 0.09, on the contrary, there was no significant difference in Ccr/CcrWC ratio between very old and young person with stage IV-V CKD: 1.66 (1.41-2.21) (young) vs 1.77 (1.1-2.7) (young), P = NS. Creatinine secretion pattern in very old patients with advanced chronic renal disease is similar to that observed in young ones with similar level of CKD.

Proteomic analysis of secreted protein induced by a component of prey in pitcher fluid of the carnivorous plant Nepenthes alata.

PubMed

Hatano, Naoya; Hamada, Tatsuro

2012-08-03

The Nepenthes species are carnivorous plants that have evolved a specialized leaf organ, the 'pitcher', to attract, capture, and digest insects. The digested insects provide nutrients for growth, allowing these plants to grow even in poor soil. Several proteins have been identified in the pitcher fluid, including aspartic proteases (nepenthesin I and II) and pathogenesis-related (PR) proteins (β-1,3-glucanase, class IV chitinase, and thaumatin-like protein). In this study, we collected and concentrated pitcher fluid to identify minor proteins. In addition, we tried to identify the protein secreted in response to trapping the insect. To make a similar situation in which the insect falls into the pitcher, chitin which was a major component of the insect exoskeleton was added to the fluid in the pitcher. Three PR proteins, class III peroxidase (Prx), β-1,3-glucanase, and class III chitinase, were newly identified. Prx was induced after the addition of chitin to the pitcher fluid. Proteins in the pitcher fluid of the carnivorous plant Nepenthes alata probably have two roles in nutrient supply: digestion of prey and the antibacterial effect. These results suggest that the system for digesting prey has evolved from the defense system against pathogens in the carnivorous plant Nepenthes. Copyright © 2012 Elsevier B.V. All rights reserved.

Genome of Herbaspirillum seropedicae Strain SmR1, a Specialized Diazotrophic Endophyte of Tropical Grasses

PubMed Central

Pedrosa, Fábio O.; Monteiro, Rose Adele; Wassem, Roseli; Cruz, Leonardo M.; Ayub, Ricardo A.; Colauto, Nelson B.; Fernandez, Maria Aparecida; Fungaro, Maria Helena P.; Grisard, Edmundo C.; Hungria, Mariangela; Madeira, Humberto M. F.; Nodari, Rubens O.; Osaku, Clarice A.; Petzl-Erler, Maria Luiza; Terenzi, Hernán; Vieira, Luiz G. E.; Steffens, Maria Berenice R.; Weiss, Vinicius A.; Pereira, Luiz F. P.; Almeida, Marina I. M.; Alves, Lysangela R.; Marin, Anelis; Araujo, Luiza Maria; Balsanelli, Eduardo; Baura, Valter A.; Chubatsu, Leda S.; Faoro, Helisson; Favetti, Augusto; Friedermann, Geraldo; Glienke, Chirlei; Karp, Susan; Kava-Cordeiro, Vanessa; Raittz, Roberto T.; Ramos, Humberto J. O.; Ribeiro, Enilze Maria S. F.; Rigo, Liu Un; Rocha, Saul N.; Schwab, Stefan; Silva, Anilda G.; Souza, Eliel M.; Tadra-Sfeir, Michelle Z.; Torres, Rodrigo A.; Dabul, Audrei N. G.; Soares, Maria Albertina M.; Gasques, Luciano S.; Gimenes, Ciela C. T.; Valle, Juliana S.; Ciferri, Ricardo R.; Correa, Luiz C.; Murace, Norma K.; Pamphile, João A.; Patussi, Eliana Valéria; Prioli, Alberto J.; Prioli, Sonia Maria A.; Rocha, Carmem Lúcia M. S. C.; Arantes, Olívia Márcia N.; Furlaneto, Márcia Cristina; Godoy, Leandro P.; Oliveira, Carlos E. C.; Satori, Daniele; Vilas-Boas, Laurival A.; Watanabe, Maria Angélica E.; Dambros, Bibiana Paula; Guerra, Miguel P.; Mathioni, Sandra Marisa; Santos, Karine Louise; Steindel, Mario; Vernal, Javier; Barcellos, Fernando G.; Campo, Rubens J.; Chueire, Ligia Maria O.; Nicolás, Marisa Fabiana; Pereira-Ferrari, Lilian; da Conceição Silva, José L.; Gioppo, Nereida M. R.; Margarido, Vladimir P.; Menck-Soares, Maria Amélia; Pinto, Fabiana Gisele S.; Simão, Rita de Cássia G.; Takahashi, Elizabete K.; Yates, Marshall G.; Souza, Emanuel M.

2011-01-01

The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme—GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species. PMID:21589895

Genome of Herbaspirillum seropedicae strain SmR1, a specialized diazotrophic endophyte of tropical grasses.

PubMed

Pedrosa, Fábio O; Monteiro, Rose Adele; Wassem, Roseli; Cruz, Leonardo M; Ayub, Ricardo A; Colauto, Nelson B; Fernandez, Maria Aparecida; Fungaro, Maria Helena P; Grisard, Edmundo C; Hungria, Mariangela; Madeira, Humberto M F; Nodari, Rubens O; Osaku, Clarice A; Petzl-Erler, Maria Luiza; Terenzi, Hernán; Vieira, Luiz G E; Steffens, Maria Berenice R; Weiss, Vinicius A; Pereira, Luiz F P; Almeida, Marina I M; Alves, Lysangela R; Marin, Anelis; Araujo, Luiza Maria; Balsanelli, Eduardo; Baura, Valter A; Chubatsu, Leda S; Faoro, Helisson; Favetti, Augusto; Friedermann, Geraldo; Glienke, Chirlei; Karp, Susan; Kava-Cordeiro, Vanessa; Raittz, Roberto T; Ramos, Humberto J O; Ribeiro, Enilze Maria S F; Rigo, Liu Un; Rocha, Saul N; Schwab, Stefan; Silva, Anilda G; Souza, Eliel M; Tadra-Sfeir, Michelle Z; Torres, Rodrigo A; Dabul, Audrei N G; Soares, Maria Albertina M; Gasques, Luciano S; Gimenes, Ciela C T; Valle, Juliana S; Ciferri, Ricardo R; Correa, Luiz C; Murace, Norma K; Pamphile, João A; Patussi, Eliana Valéria; Prioli, Alberto J; Prioli, Sonia Maria A; Rocha, Carmem Lúcia M S C; Arantes, Olívia Márcia N; Furlaneto, Márcia Cristina; Godoy, Leandro P; Oliveira, Carlos E C; Satori, Daniele; Vilas-Boas, Laurival A; Watanabe, Maria Angélica E; Dambros, Bibiana Paula; Guerra, Miguel P; Mathioni, Sandra Marisa; Santos, Karine Louise; Steindel, Mario; Vernal, Javier; Barcellos, Fernando G; Campo, Rubens J; Chueire, Ligia Maria O; Nicolás, Marisa Fabiana; Pereira-Ferrari, Lilian; Silva, José L da Conceição; Gioppo, Nereida M R; Margarido, Vladimir P; Menck-Soares, Maria Amélia; Pinto, Fabiana Gisele S; Simão, Rita de Cássia G; Takahashi, Elizabete K; Yates, Marshall G; Souza, Emanuel M

2011-05-01

The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme--GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species.

Novel N-substituted aminobenzamide scaffold derivatives targeting the dipeptidyl peptidase-IV enzyme.

PubMed

Al-Balas, Qosay A; Sowaileh, Munia F; Hassan, Mohammad A; Qandil, Amjad M; Alzoubi, Karem H; Mhaidat, Nizar M; Almaaytah, Ammar M; Khabour, Omar F

2014-01-01

The dipeptidyl peptidase-IV (DPP-IV) enzyme is considered a pivotal target for controlling normal blood sugar levels in the body. Incretins secreted in response to ingestion of meals enhance insulin release to the blood, and DPP-IV inactivates these incretins within a short period and stops their action. Inhibition of this enzyme escalates the action of incretins and induces more insulin to achieve better glucose control in diabetic patients. Thus, inhibition of this enzyme will lead to better control of blood sugar levels. In this study, computer-aided drug design was used to help establish a novel N-substituted aminobenzamide scaffold as a potential inhibitor of DPP-IV. CDOCKER software available from Discovery Studio 3.5 was used to evaluate a series of designed compounds and assess their mode of binding to the active site of the DPP-IV enzyme. The designed compounds were synthesized and tested against a DPP-IV enzyme kit provided by Enzo Life Sciences. The synthesized compounds were characterized using proton and carbon nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, and determination of melting point. Sixty-nine novel compounds having an N-aminobenzamide scaffold were prepared, with full characterization. Ten of these compounds showed more in vitro activity against DPP-IV than the reference compounds, with the most active compounds scoring 38% activity at 100 μM concentration. The N-aminobenzamide scaffold was shown in this study to be a valid scaffold for inhibiting the DPP-IV enzyme. Continuing work could unravel more active compounds possessing the same scaffold.

Oral administration of arginine enhances the growth hormone response to growth hormone releasing hormone in short children.

PubMed

Loche, S; Carta, D; Muntoni, A C; Corda, R; Pintor, C

1993-10-01

We have evaluated the effect of oral administration of arginine chlorhydrate on the growth hormone response to growth hormone releasing hormone in a group of nine short prepubertal children (six boys and four girls). Arginine chlorhydrate 10 g, administered orally 60 min before an i.v. bolus injection of growth hormone releasing hormone 1-29, 1 microgram/kg, significantly enhanced the growth hormone response to the neuropeptide, confirming the results of previous studies which used the i.v. route. Furthermore, our data strengthen the view that the effects of arginine chlorhydrate on growth hormone secretion are mediated by inhibition of endogenous somatostatin release.

Involvement of serotoninergic pathways in the control of luteinizing hormone secretion in red deer hinds.

PubMed

Villa-Diaz, L G; Barrell, G K

1999-01-01

Two experiments were conducted to determine whether serotoninergic pathways, which are implicated in the neuroendocrine regulation of luteininzing hormone (LH) secretion in domestic animals, have a similar action in red deer hinds. In the non-breeding season (August), ovariectomized (n = 5) and ovariectomized-thyroidectomized (n = 5) hinds received a vehicle solution followed 4 h later by either serotonin (66 microg kg(-1) i.v.) every 10 min for a further 4 h or the serotonin antagonist, cyproheptadine (3 mg kg(-1) i.v.) as a single injection. This procedure was repeated in the breeding season (June). In the non-breeding season serotonin was without effect, but cyproheptadine reduced LH pulse frequency and amplitude in ovariectomized-thyroidectomized hinds (P<0.01). During the breeding season, serotonin reduced LH pulse amplitude in ovariectomized hinds (P<0.05) and cyproheptadine reduced LH pulse frequency in both ovariectomized and ovariectomized-thyroidectomized hinds (P<0.05 and P<0.01, respectively). On each occasion, cyproheptadine increased (P<0.01) plasma prolactin concentration, whereas serotonin had no effect. These results indicate a stimulatory role for serotoninergic neurons on the hypothalamic GnRH pulse generator mechanism of red deer hinds during the breeding season. In a second experiment, the LH response to GnRH (5 microg i.v.) was examined in ovariectomized hinds (n = 5) following administration of a serotonin infusion (6.6 microg kg(-1) min(-1) i.v. for 15 min), cyproheptadine (3 mg kg(-1) i.v. as a single dose) or vehicle, in the breeding season (July) after induction of halothane anaesthesia and in the non-breeding season (December) without anaesthesia. Halothane anaesthesia eliminated endogenous pulses of LH. In comparison with the vehicle-treated controls, the response of plasma LH to exogenous GnRH was not altered by serotonin or cyproheptadine in either season, which shows that serotonin has no effect on LH release at the pituitary gland level in these animals. It was concluded that in the regulation of LH release in red deer hinds, serotoninergic pathways have a stimulatory role operating at the hypothalamic level.

Hfq Influences Multiple Transport Systems and Virulence in the Plant Pathogen Agrobacterium tumefaciens

PubMed Central

Wilms, Ina; Möller, Philip; Stock, Anna-Maria; Gurski, Rosemarie; Lai, Erh-Min

2012-01-01

The Hfq protein mediates gene regulation by small RNAs (sRNAs) in about 50% of all bacteria. Depending on the species, phenotypic defects of an hfq mutant range from mild to severe. Here, we document that the purified Hfq protein of the plant pathogen and natural genetic engineer Agrobacterium tumefaciens binds to the previously described sRNA AbcR1 and its target mRNA atu2422, which codes for the substrate binding protein of an ABC transporter taking up proline and γ-aminobutyric acid (GABA). Several other ABC transporter components were overproduced in an hfq mutant compared to their levels in the parental strain, suggesting that Hfq plays a major role in controlling the uptake systems and metabolic versatility of A. tumefaciens. The hfq mutant showed delayed growth, altered cell morphology, and reduced motility. Although the DNA-transferring type IV secretion system was produced, tumor formation by the mutant strain was attenuated, demonstrating an important contribution of Hfq to plant transformation by A. tumefaciens. PMID:22821981

Urinary retention and syndrome of inappropriate antidiuretic hormone secretion (SIADH) secondary to impacted gravid uterus.

PubMed

Irani, M; Fisher, N; Mor, A; Bensinger, G

2016-06-01

Urinary retention is an emergency that rarely occurs during pregnancy. Previous case reports have suggested multiple risk factors that can cause the gravid uterus to become impacted in the pelvis leading to lower bladder or urethral compression with subsequent urinary retention. However, no cases of urinary obstruction in a pregnancy that was complicated with severe electrolyte imbalance have been reported. To our knowledge, we report the first case of a 31-year-old woman presenting at 8 weeks' gestation with acute urinary retention caused by a retroflexed, retroverted uterus with a 6-cm posterior uterine fibroid leading to syndrome of inappropriate antidiuretic hormone secretion and severe hyponatremia requiring intensive care unit admission. The cornerstones of effective management of urinary retention should include: (i) urgent bladder catheterization; (ii) assessment of sodium levels to rule out syndrome of inappropriate antidiuretic hormone secretion, and prompt treatment before neurological damage occurs; (iii) reduction of the impacted uterus; and (iv) monitoring for post-obstructive diuresis. © 2016 Japan Society of Obstetrics and Gynecology.

Mutant p53 proteins alter cancer cell secretome and tumour microenvironment: Involvement in cancer invasion and metastasis.

PubMed

Cordani, Marco; Pacchiana, Raffaella; Butera, Giovanna; D'Orazi, Gabriella; Scarpa, Aldo; Donadelli, Massimo

2016-07-01

An ever-increasing number of studies highlight the role of mutant p53 proteins in the alteration of cancer cell secretome and in the modification of tumour microenvironment, sustaining an invasive phenotype of cancer cell. The knowledge of the molecular mechanisms underlying the interplay between mutant p53 proteins and the microenvironment is becoming fundamental for the identification of both efficient anticancer therapeutic strategies and novel serum biomarkers. In this review, we summarize the novel findings concerning the regulation of secreted molecules by cancer cells bearing mutant TP53 gene. In particular, we highlight data from available literature, suggesting that mutant p53 proteins are able to (i) alter the secretion of enzymes involved in the modulation of extracellular matrix components; (ii) alter the secretion of inflammatory cytokines; (iii) increase the extracellular acidification; and (iv) regulate the crosstalk between cancer and stromal cells. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effect of bombesin on pancreatic secretion and gall bladder motility of the chicken.

PubMed

Linari, G; Linari, M B

1975-12-01

Bombesin strongly stimulated the chicken pancreatic secretion. When given by i.v. infusion, the threshold dose was of the order of 7.5-45.0 ng/kg/min and maximum enzyme output was obtained at a rate of 60 ng/kg/min. In addition to total enzyme output, enzyme concentration was also increased. Caerulein displayed a more potent stimulant effect, but composition of juice produced by the two polypeptides was similar. Tachyphylaxis occurred only with bombesin. Neither atropine nor gastric acidification affected the response to bombesin. Bombesin was totally ineffective in promoting gall bladder emptying. It is suggested that in the chicken, bombesin acts on the exocrine pancreas indirectly through release of an endogenous pancreozymin possibly devoid of cholecystokinetic activity.

Influence of hyperthyroidism on growth hormone secretion.

PubMed

Valcavi, R; Dieguez, C; Zini, M; Muruais, C; Casanueva, F; Portioli, I

1993-05-01

Hyperthyroidism is associated with altered GH secretion. Whether this is due to changes of somatotroph responsiveness or reflects an alteration in negative feedback signals at the hypothalamic level is unknown. We therefore performed a series of studies to shed some light onto this issue. Study 1: GHRH (1 microgram/kg b.w.) was injected i.v. in 38 hyperthyroid patients and in 30 normal subjects; in 11 of the patients the GHRH test was repeated following methimazole-induced remission of hyperthyroidism. Study 2: hGH (2 U i.v.) or saline were administered 3 hours prior to GHRH; six hyperthyroid patients and six normal subjects were studied. Study 3: ten normal subjects and ten hyperthyroid patients were given 75 g oral glucose or water 30 minutes before GHRH. Study 4: 11 normal subjects and eight hyperthyroid patients were studied. TRH or vehicle were dissolved in 250 ml of saline solution and infused at a rate of 400 micrograms/h for 150 minutes. Thirty minutes after the beginning of the infusions, L-arginine (30 g infused over 45 min i.v.) was administered. Hyperthyroid patients were compared to normal subjects. Growth hormone was measured by RIA at 15-minute intervals. GH responses to GHRH were subnormal in hyperthyroid patients. Following antithyroid drug treatment with methimazole, GH responses to GHRH increased in these patients in comparison to pretreatment values. Serum IGF-I levels, which were elevated before treatment, decreased after methimazole administration. Exogenous GH administration induced a clear decrease of GH responses to GHRH in both control and hyperthyroid subjects. On the other hand, oral glucose load decreased the GH responses to GHRH in normal but not in hyperthyroid subjects. TRH administration did not modify the GH responses to arginine in either normal subjects or hyperthyroid patients. Hyperthyroidism is associated with increased serum IGF-I levels and marked alterations in the neuroregulation of GH secretion. These changes involve decreased GH responsiveness to GHRH at the pituitary level and, at the hypothalamic level, a lack of suppressive effect of an oral glucose load. The normal inhibitory effect of exogenous GH administration but not of an oral glucose load in hyperthyroid patients suggests that these two feedback signals act through different mechanisms. The lack of effect of a TRH infusion on GH responses to L-arginine in normal and hyperthyroid patients makes an inhibitory role for TRH in GH secretion unlikely, at least in Caucasian subjects.

Xanthomonas campestris pv. campestris (cause of black rot of crucifers) in the genomic era is still a worldwide threat to brassica crops.

PubMed

Vicente, Joana G; Holub, Eric B

2013-01-01

Xanthomonas campestris pv. campestris (Xcc) (Pammel) Dowson is a Gram-negative bacterium that causes black rot, the most important disease of vegetable brassica crops worldwide. Intensive molecular investigation of Xcc is gaining momentum and several whole genome sequences are available. Bacteria; Phylum Proteobacteria; Class Gammaproteobacteria; Order Xanthomonadales; Family Xanthomonadacea; Genus Xanthomonas; Species X. campestris. Xcc can cause disease in a large number of species of Brassicaceae (ex-Cruciferae), including economically important vegetable Brassica crops and a number of other cruciferous crops, ornamentals and weeds, including the model plant Arabidopsis thaliana. Black rot is a systemic vascular disease. Typical disease symptoms include V-shaped yellow lesions starting from the leaf margins and blackening of the veins. Collections of Xcc isolates have been differentiated into physiological races based on the response of several brassica species lines. Black rot is a seed-borne disease. The disease is favoured by warm, humid conditions and can spread rapidly from rain dispersal and irrigation water. The control of black rot is difficult and relies on the use of pathogen-free planting material and the elimination of other potential inoculum sources (infected crop debris and cruciferous weeds). Major gene resistance is very rare in B. oleracea (brassica C genome). Resistance is more readily available in other species, including potentially useful sources of broad-spectrum resistance in B. rapa and B. carinata (A and BC genomes, respectively) and in the wild relative A. thaliana. The reference genomes of three isolates have been released. The genome consists of a single chromosome of approximately 5 100 000 bp, with a GC content of approximately 65% and an average predicted number of coding DNA sequences (CDS) of 4308. Three different secretion systems have been identified and studied in Xcc. The gene clusters xps and xcs encode a type II secretion system and xps genes have been linked to pathogenicity. The role of the type IV secretion system in pathogenicity is still uncertain. The hrp gene cluster encodes a type III secretion system that is associated with pathogenicity. An inventory of candidate effector genes has been assembled based on homology with known effectors. A range of other genes have been associated with virulence and pathogenicity, including the rpf, gum and wxc genes involved in the regulation of the synthesis of extracellular degrading enzymes, xanthan gum and lipopolysaccharides. http://www.xanthomonas.org/ © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

From mucolipidosis type IV to Ebola: TRPML and two-pore channels at the crossroads of endo-lysosomal trafficking and disease.

PubMed

Grimm, Christian; Butz, Elisabeth; Chen, Cheng-Chang; Wahl-Schott, Christian; Biel, Martin

2017-11-01

What do lysosomal storage disorders such as mucolipidosis type IV have in common with Ebola, cancer cell migration, or LDL-cholesterol trafficking? LDL-cholesterol, certain bacterial toxins and viruses, growth factors, receptors, integrins, macromolecules destined for degradation or secretion are all sorted and transported via the endolysosomal system (ES). There are several pathways known in the ES, e.g. the degradation, the recycling, or the retrograde trafficking pathway. The ES comprises early and late endosomes, lysosomes and recycling endosomes as well as autophagosomes and lysosome related organelles. Contact sites between the ES and the endoplasmic reticulum or the Golgi apparatus may also be considered part of it. Dysfunction of this complex intracellular machinery can cause or contribute to the development of a number of diseases ranging from neurodegenerative, infectious, or metabolic diseases to retinal and pigmentation disorders as well as cancer and autophagy-related diseases. Endolysosomal ion channels such as mucolipins (TRPMLs) and two-pore channels (TPCs) play an important role in intracellular cation/calcium signaling and homeostasis and appear to critically contribute to the proper function of the endolysosomal trafficking network. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pathogen vacuole purification from legionella-infected amoeba and macrophages.

PubMed

Hoffmann, Christine; Finsel, Ivo; Hilbi, Hubert

2013-01-01

Legionella pneumophila replicates intracellularly in environmental and immune phagocytes within a unique membrane-bound compartment, the Legionella-containing vacuole (LCV). Formation of LCVs is strictly dependent on the Icm/Dot type IV secretion system and the translocation of "effector" proteins into the cell. Some effector proteins decorate the LCV membrane and subvert host cell vesicle trafficking pathways. Here we describe a method to purify intact LCVs from Dictyostelium discoideum amoebae and RAW 264.7 murine macrophages. The method comprises a two-step protocol: first, LCVs are enriched by immuno-magnetic separation using an antibody against a bacterial effector protein specifically localizing to the LCV membrane, and second, the LCVs are further purified by density gradient centrifugation. The purified LCVs can be characterized by proteomics and other biochemical approaches.

Bombesin-like peptides stimulate growth hormone secretion mediated by the gastrin-releasing peptide receptor in cattle.

PubMed

Zhao, Hongqiong; Matsuda, Seinosuke; Thanthan, Sint; Yannaing, Swe; Kuwayama, Hideto

2012-10-01

This study was designed to determine the effects of bombesin-like peptides (BLPs) on the secretion of growth hormone (GH) and to characterize the receptor subtypes mediating these effects in cattle. Four experiments were conducted: (1) six steers were randomly assigned to receive intravenous (IV) bolus injections of 0, 0.2, 1.0, 12.5 and 50.0 μg/kg neuromedin C (NMC); (2) seven pre-weaned calves were IV injected with 1.0 μg/kg NMC; (3) six steers were IV injected with 2.5μg/kg bovine gastrin-releasing peptide (GRP), 1.0 μg/kg NMC combined with 20.0 μg/kg [d-Lys(3)]-GHRP-6 (an antagonist for the GH secretagogue receptor type 1a [GHS-R1a]), 1.0 μg/kg NMC combined with 20.0 μg/kg N-acetyl-GRP(20-26)-OCH(2)CH(3) (N-GRP-EE, an antagonist for the GRP receptor), 20.0 μg/kg N-GRP-EE alone, 1.0 μg/kg neuromedin B (NMB); and (4) four rats were IV injected 1.0 μg/kg NMC. A serial blood sample was collected before and after injection. Plasma GH levels dose-dependently increased at 5 min after NMC injection and the minimal effective dose was 1.0 μg/kg. Plasma GH level was elevated by GRP, but not by NMB. The NMC-induced elevation of GH was completely blocked by N-GRP-EE. The administration of NMC elevated GH level in pre-weaned calves but not in rats. Ghrelin level was unaffected by any treatments; and [d-Lys(3)]-GHRP-6 did not block the NMC-induced elevation of GH. The results indicate BLP-induced elevation of GH levels is mediated by the GRP receptor but not through a ghrelin/GHS-R1a pathway in cattle. Copyright © 2012 Elsevier Inc. All rights reserved.

Adjuvant effects of invariant NKT cell ligand potentiates the innate and adaptive immunity to an inactivated H1N1 swine influenza virus vaccine in pigs.

PubMed

Dwivedi, Varun; Manickam, Cordelia; Dhakal, Santosh; Binjawadagi, Basavaraj; Ouyang, Kang; Hiremath, Jagadish; Khatri, Mahesh; Hague, Jacquelyn Gervay; Lee, Chang Won; Renukaradhya, Gourapura J

2016-04-15

Pigs are considered as the source of some of the emerging human flu viruses. Inactivated swine influenza virus (SwIV) vaccine has been in use in the US swine herds, but it failed to control the flu outbreaks. The main reason has been attributed to lack of induction of strong local mucosal immunity in the respiratory tract. Invariant natural killer T (iNKT) cell is a unique T cell subset, and activation of iNKT cell using its ligand α-Galactosylceramide (α-GalCer) has been shown to potentiate the cross-protective immunity to inactivated influenza virus vaccine candidates in mice. Recently, we discovered iNKT cell in pig and demonstrated its activation using α-GalCer. In this study, we evaluated the efficacy of an inactivated H1N1 SwIV coadministered with α-GalCer intranasally against a homologous viral challenge. Our results demonstrated the potent adjuvant effects of α-GalCer in potentiating both innate and adaptive immune responses to SwIV Ags in the lungs of pigs, which resulted in reduction in the lung viral load by 3 logs compared to without adjuvant. Immunologically, in the lungs of pigs vaccinated with α-GalCer an increased virus specific IgA response, IFN-α secretion and NK cell-cytotoxicity was observed. In addition, iNKT cell-stimulation enhanced the secretion of Th1 cytokines (IFN-γ and IL-12) and reduced the production of immunosuppressive cytokines (IL-10 and TGF-β) in the lungs of pigs⋅ In conclusion, we demonstrated for the first time iNKT cell adjuvant effects in pigs to SwIV Ags through augmenting the innate and adaptive immune responses in the respiratory tract. Copyright © 2016 Elsevier B.V. All rights reserved.

Effector prediction in host-pathogen interaction based on a Markov model of a ubiquitous EPIYA motif

PubMed Central

2010-01-01

Background Effector secretion is a common strategy of pathogen in mediating host-pathogen interaction. Eight EPIYA-motif containing effectors have recently been discovered in six pathogens. Once these effectors enter host cells through type III/IV secretion systems (T3SS/T4SS), tyrosine in the EPIYA motif is phosphorylated, which triggers effectors binding other proteins to manipulate host-cell functions. The objectives of this study are to evaluate the distribution pattern of EPIYA motif in broad biological species, to predict potential effectors with EPIYA motif, and to suggest roles and biological functions of potential effectors in host-pathogen interactions. Results A hidden Markov model (HMM) of five amino acids was built for the EPIYA-motif based on the eight known effectors. Using this HMM to search the non-redundant protein database containing 9,216,047 sequences, we obtained 107,231 sequences with at least one EPIYA motif occurrence and 3115 sequences with multiple repeats of the EPIYA motif. Although the EPIYA motif exists among broad species, it is significantly over-represented in some particular groups of species. For those proteins containing at least four copies of EPIYA motif, most of them are from intracellular bacteria, extracellular bacteria with T3SS or T4SS or intracellular protozoan parasites. By combining the EPIYA motif and the adjacent SH2 binding motifs (KK, R4, Tarp and Tir), we built HMMs of nine amino acids and predicted many potential effectors in bacteria and protista by the HMMs. Some potential effectors for pathogens (such as Lawsonia intracellularis, Plasmodium falciparum and Leishmania major) are suggested. Conclusions Our study indicates that the EPIYA motif may be a ubiquitous functional site for effectors that play an important pathogenicity role in mediating host-pathogen interactions. We suggest that some intracellular protozoan parasites could secrete EPIYA-motif containing effectors through secretion systems similar to the T3SS/T4SS in bacteria. Our predicted effectors provide useful hypotheses for further studies. PMID:21143776

Interleukin-10 functions in vitro and in vivo to inhibit bacterial DNA-induced secretion of interleukin-12.

PubMed

Anitescu, M; Chace, J H; Tuetken, R; Yi, A K; Berg, D J; Krieg, A M; Cowdery, J S

1997-12-01

Bacterial DNA (bDNA) has a number of biologic properties, including the ability to induce interleukin-12 (IL-12) production by macrophages. We studied the role of the regulatory cytokine IL-10 as a potential inhibitor of bDNA-induced IL-12 production. IL-10 concentrations as low as 0.3 ng/ml profoundly inhibited bDNA-induced macrophage IL-12 production as measured by Elispot analysis of IL-12 p40-secreting cells. Additionally, we found that IL-10 inhibited bDNA-induced IL-12 secretion by the macrophage cell lines J774 and RAW 264. Preincubation of splenic adherent cells with IL-10 markedly reduced bDNA-induced transcription of IL-12 p40 mRNA. Interestingly, after 2 h of exposure, bDNA also induces transcription of IL-10 mRNA by splenic adherent cells. The importance of IL-10 in the in vivo regulation of bDNA-induced cytokine secretion was illustrated by the response of mice with disrupted IL-10 genes (IL-10 ko mice) to i.v. bDNA challenge. Compared to +/+ mice, IL-10 knockout (ko) mice exhibited increased numbers of IL-12 and interferon-gamma (IFN-gamma)-secreting cells following either single or repeated challenge with bDNA. These findings indicate that IL-10 plays a key role in regulating bDNA-induced production of inflammatory cytokines.

Quantitative proteomics unravels that the post-transcriptional regulator Crc modulates the generation of vesicles and secreted virulence determinants of Pseudomonas aeruginosa.

PubMed

Reales-Calderón, Jose Antonio; Corona, Fernando; Monteoliva, Lucía; Gil, Concha; Martínez, Jose Luis

2015-09-08

Recent research indicates that the post-transcriptional regulator Crc modulates susceptibility to antibiotics and virulence in Pseudomonas aeruginosa. Several P. aeruginosa virulence factors are secreted or engulfed in vesicles. To decipher the Crc modulation of P. aeruginosa virulence, we constructed a crc deficient mutant and measure the proteome associated extracellular vesicles and the vesicle-free secretome using iTRAQ. Fifty vesicle-associated proteins were more abundant and 14 less abundant in the crc-defective strain, whereas 37 were more abundant and 17 less abundant in the vesicle-free secretome. Among them, virulence determinants, such as ToxA, protease IV, azurin, chitin-binding protein, PlcB and Hcp1, were less abundant in the crc-defective mutant. Transcriptomic analysis revealed that some of the observed changes were post-transcriptional and, thus, could be attributed to a direct Crc regulatory role; whereas, for other differentially secreted proteins, the regulatory role was likely indirect. We also observed that the crc mutant presented an impaired vesicle-associated secretion of quorum sensing signal molecules and less cytotoxicity than its wild-type strain. Our results offer new insights into the mechanisms by which Crc regulates P. aeruginosa virulence, through the modulation of vesicle formation and secretion of both virulence determinants and quorum sensing signals. This article is part of a Special Issue entitled: HUPO 2014. Published by Elsevier B.V.

Computational and Experimental Analysis of the Secretome of Methylococcus capsulatus (Bath)

PubMed Central

Indrelid, Stine; Mathiesen, Geir; Jacobsen, Morten; Lea, Tor; Kleiveland, Charlotte R.

2014-01-01

The Gram-negative methanotroph Methylococcus capsulatus (Bath) was recently demonstrated to abrogate inflammation in a murine model of inflammatory bowel disease, suggesting interactions with cells involved in maintaining mucosal homeostasis and emphasizing the importance of understanding the many properties of M. capsulatus. Secreted proteins determine how bacteria may interact with their environment, and a comprehensive knowledge of such proteins is therefore vital to understand bacterial physiology and behavior. The aim of this study was to systematically analyze protein secretion in M. capsulatus (Bath) by identifying the secretion systems present and the respective secreted substrates. Computational analysis revealed that in addition to previously recognized type II secretion systems and a type VII secretion system, a type Vb (two-partner) secretion system and putative type I secretion systems are present in M. capsulatus (Bath). In silico analysis suggests that the diverse secretion systems in M.capsulatus transport proteins likely to be involved in adhesion, colonization, nutrient acquisition and homeostasis maintenance. Results of the computational analysis was verified and extended by an experimental approach showing that in addition an uncharacterized protein and putative moonlighting proteins are released to the medium during exponential growth of M. capsulatus (Bath). PMID:25479164

Legionella oakridgensis ATCC 33761 genome sequence and phenotypic characterization reveals its replication capacity in amoebae.

PubMed

Brzuszkiewicz, Elzbieta; Schulz, Tino; Rydzewski, Kerstin; Daniel, Rolf; Gillmaier, Nadine; Dittmann, Christine; Holland, Gudrun; Schunder, Eva; Lautner, Monika; Eisenreich, Wolfgang; Lück, Christian; Heuner, Klaus

2013-12-01

Legionella oakridgensis is able to cause Legionnaires' disease, but is less virulent compared to L. pneumophila strains and very rarely associated with human disease. L. oakridgensis is the only species of the family legionellae which is able to grow on media without additional cysteine. In contrast to earlier publications, we found that L. oakridgensis is able to multiply in amoebae. We sequenced the genome of L. oakridgensis type strain OR-10 (ATCC 33761). The genome is smaller than the other yet sequenced Legionella genomes and has a higher G+C-content of 40.9%. L. oakridgensis lacks a flagellum and it also lacks all genes of the flagellar regulon except of the alternative sigma-28 factor FliA and the anti-sigma-28 factor FlgM. Genes encoding structural components of type I, type II, type IV Lvh and type IV Dot/Icm, Sec- and Tat-secretion systems could be identified. Only a limited set of Dot/Icm effector proteins have been recognized within the genome sequence of L. oakridgensis. Like in L. pneumophila strains, various proteins with eukaryotic motifs and eukaryote-like proteins were detected. We could demonstrate that the Dot/Icm system is essential for intracellular replication of L. oakridgensis. Furthermore, we identified new putative virulence factors of Legionella. Copyright © 2013 Elsevier GmbH. All rights reserved.

Asymmetric distribution of type IV pili triggered by directional light in unicellular cyanobacteria

PubMed Central

Nishizaka, Takayuki

2017-01-01

The type IV pili (T4P) system is a supermolecular machine observed in prokaryotes. Cells repeat the cycle of T4P extension, surface attachment, and retraction to drive twitching motility. Although the properties of T4P as a motor have been scrutinized with biophysics techniques, the mechanism of regulation remains unclear. Here we provided the framework of the T4P dynamics at the single-cell level in Synechocystis sp. PCC6803, which can recognize light direction. We demonstrated that the dynamics was detected by fluorescent beads under an optical microscope and controlled by blue light that induces negative phototaxis; extension and retraction of T4P was activated at the forward side of lateral illumination to move away from the light source. Additionally, we directly visualized each pilus by fluorescent labeling, allowing us to quantify their asymmetric distribution. Finally, quantitative analyses of cell tracking indicated that T4P was generated uniformly within 0.2 min after blue-light exposure, and within the next 1 min the activation became asymmetric along the light axis to achieve directional cell motility; this process was mediated by the photo-sensing protein, PixD. This sequential process provides clues toward a general regulation mechanism of T4P system, which might be essentially common between archaella and other secretion apparatuses. PMID:28584115

Effects of humic acid concentration on the microbially-mediated reductive solubilization of Pu(IV) polymers.

PubMed

Xie, Jinchuan; Han, Xiaoyuan; Wang, Weixian; Zhou, Xiaohua; Lin, Jianfeng

2017-10-05

The role of humic acid concentration in the microbially-mediated reductive solubilization of Pu(IV) polymers remains unclear until now. The effects of humic concentration (0-150.5mg/L) on the rate and extent of reduction of polymeric Pu(IV) were studied under anaerobic and pH 7.2 conditions. The results show that Shewanella putrefaciens, secreting flavins as endogenous electron shuttles, cannot notably stimulate the reduction of polymeric Pu(IV). In the presence of humic acids, the reduction rate of polymeric Pu(IV) increased with increasing humic concentrations (0-15.0mg/L): e.g., a 102-fold increase from 4.1×10 -15 (HA=0) to 4.2×10 -13 mol Pu(III) aq /h (HA=15.0mg/L). The bioreduced humic acids by S. putrefaciens facilitated the extracellular electron transfer to Pu(IV) polymers and thus the reduction of polymeric Pu(IV) to Pu(III) aq became thermodynamically favorable. However, the reduction rate did not increase but decrease with increasing humic concentrations from 15.0 to 150.5mg/L. Humic coatings formed on the polymer surfaces at relatively high humic concentrations limited the electron transfer to the polymers and thus decreased the reduction rate. The finding of the dynamic role of humic acids in the bioreductive solubilization may be helpful in evaluating Pu mobility in the geosphere. Copyright © 2017 Elsevier B.V. All rights reserved.

Absence of growth hormone (GH) secretion after the administration of either GH-releasing hormone (GHRH), GH-releasing peptide (GHRP-6), or GHRH plus GHRP-6 in children with neonatal pituitary stalk transection.

PubMed

Pombo, M; Barreiro, J; Peñalva, A; Peino, R; Dieguez, C; Casanueva, F F

1995-11-01

GH-releasing peptide (GHRP-6; His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) is a synthetic compound that releases GH in a specific and dose-related manner through mechanisms and a point of action that are mostly unknown, but different from those of GHRH. In man, GHRP-6 is more efficacious than GHRH, and a striking synergistic action occurs when both compounds are administered together. To explain such a synergistic effect, it has been postulated, but not proven, that GHRP-6 acts through a double mechanism, with actions exerted at the pituitary and the hypothalamic level. On the other hand, patients with the syndrome of GH deficiency due to perinatal pituitary stalk transection have any hypothalamic factor nonoperandi. The aim of the present study was 3-fold: 1) to further understand how relevant, if at all, the hypothalamic action of GHRP-6 is for GH regulation; 2) to evaluate whether GHRP-6 plus GHRH could be a suitable diagnostic tool in children with pituitary stalk transection; and 3) to compare these results with similar published studies performed in patients with hypothalamo-pituitary disconnection, who developed the disease as adults. Seven patients with GH deficiency and different degrees of panhypopituitarism due to perinatal pituitary stalk transection and 7 age- and sex-matched normal controls were studied. The subjects underwent 3 different tests on separate occasions, being challenged with GHRH (1 microgram/kg, iv), GHRP-6 (1 microgram/kg, iv), or GHRH plus GHRP-6. GH was analyzed as the area under the curve (mean +/- SE; micrograms per L/90 min). In normal subjects, GH secretion was 1029 +/- 202 after GHRH treatment, 1221 +/- 345 after GHRP-6, and 3542 +/- 650 after GHRH plus GHRP-6; the latter value was significantly (P < 0.05) higher than the secretion elicited by GHRH or GHRP-6 alone. In the group of patients with perinatal pituitary stalk transection, the level of GH after GHRH treatment was 116 +/- 22 and was even more reduced (P < 0.05) after GHRP-6 treatment (37 +/- 8). After GHRH plus GHRP-6, GH secretion in those patients was 177 +/- 27, significantly higher (P < 0.05) than the secretion induced by either GHRH or GHRP-6 alone. Individually examined, none of the patients tested with the most potent stimulus known to date (GHRH plus GHRP-6) exhibited GH secretion greater than 5 micrograms/L.(ABSTRACT TRUNCATED AT 400 WORDS)

Variation in the ovine cortisol response to systemic bacterial endotoxin challenge is predominantly determined by signalling within the hypothalamic-pituitary-adrenal axis

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

You Qiumei; Karrow, Niel A.; Cao Honghe

Bi-directional communication between the neuroendocrine and immune systems is designed, in part, to maintain or restore homeostasis during physiological stress. Exposure to endotoxin during Gram-negative bacterial infection for example, elicits the release of pro-inflammatory cytokines that activate the hypothalamic-pituitary-adrenal axis (HPAA). The secretion of adrenal glucocorticoids subsequently down regulates the host inflammatory response, minimizing potential tissue damage. Sequence and epigenetic variants in genes involved in regulating the neuroendocrine and immune systems are likely to contribute to individual differences in the HPAA response, and this may influence the host anti-inflammatory response to toxin exposure and susceptibility to inflammatory disease. In thismore » study, high (HCR) and low (LCR) cortisol responders were selected from a normal population of 110 female sheep challenged iv with Escherichia coli endotoxin (400 ng/kg) to identify potential determinants that contribute to variation in the cortisol response phenotype. This phenotype was stable over several years in the HCR and LCR animals, and did not appear to be attributed to differences in expression of hepatic immune-related genes or systemic pro-inflammatory cytokine concentrations. Mechanistic studies using corticotrophin-releasing factor (0.5 {mu}g/kg body weight), arginine vasopressin (0.5 {mu}g/kg), and adrenocorticotropic hormone (0.5 {mu}g/kg) administered iv demonstrated that variation in this phenotype is largely determined by signalling within the HPAA. Future studies will use this ovine HCR/LCR model to investigate potential genetic and epigenetic variants that may contribute to variation in cortisol responsiveness to bacterial endotoxin.« less

Effect of rebamipide on gastric bleeding and ulcerogenic responses induced by aspirin plus clopidogrel under stimulation of acid secretion in rats.

PubMed

Takeuchi, Koji; Takayama, Shinichi; Hashimoto, Erika; Itayama, Misaki; Amagase, Kikuko; Izuhara, Chitose

2014-12-01

We examined the prophylactic effect of rebamipide on gastric bleeding induced by the perfusion of aspirin (acetylsalicylic acid [ASA]) plus clopidogrel under the stimulation of acid secretion in rats. Under urethane anesthesia, acid secretion was stimulated by the i.v. infusion of histamine (8 mg/kg/h), and the stomach was perfused with 25 mmol/L ASA at a rate of 0.4 mL/min. Gastric bleeding was evaluated as the concentration of hemoglobin in the perfusate. Clopidogrel (30 mg/kg) was given p.o. 24 h before the perfusion. Rebamipide (3-30 mg/kg) or other antiulcer drugs were given i.d. before the ASA perfusion. Slight gastric bleeding or damage was observed with the perfusion of ASA under the stimulation of acid secretion, whereas these responses were significantly increased in the presence of clopidogrel. Both omeprazole and famotidine inhibited acid secretion and prevented these responses to ASA plus clopidogrel. Rebamipide had no effect on acid secretion, but dose-dependently prevented gastric bleeding in response to ASA plus clopidogrel, with the degree of inhibition being almost equivalent to that of the antisecretory drugs, and the same effects were obtained with the gastroprotective drugs, irsogladine and teprenone. These agents also reduced the severity of gastric lesions, although the effects were less than those of the antisecretory drugs. These results suggest that the antiplatelet drug, clopidogrel, increases gastric bleeding induced by ASA under the stimulation of acid secretion, and the gastroprotective drug, rebamipide, is effective in preventing the gastric bleeding induced under such conditions, similar to antisecretory drugs. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

Pulsatile LH secretion and ovarian follicular wave emergence and growth in anestrous ewes.

PubMed

Seekallu, Srinivas V; Barrett, David M W; Toosi, Behzad M; Clarke, Kelsey; Ewen, Kirk A; Duggavathi, Rajesha; Davies, Kate L; Pattullo, Kim M; Bagu, Edward T; Rawlings, Norman C

2010-10-01

The objective of this study was to determine if pulsatile LH secretion was needed for ovarian follicular wave emergence and growth in the anestrous ewe. In Experiment 1, ewes were either large or small (10 x 0.47 or 5 x 0.47 cm, respectively; n = 5/group) sc implants releasing estradiol-17 beta for 10 d (Day 0 = day of implant insertion), to suppress pulsed LH secretion, but not FSH secretion. Five sham-operated control ewes received no implants. In Experiment 2, 12 ewes received large estradiol-releasing implants for 12 d (Day 0 = day of implant insertion); six were given GnRH (200 ng IV) every 4 h for the last 6 d that the implants were in place (to reinitiate pulsed LH secretion) whereas six Control ewes were given saline. Ovarian ultrasonography and blood sampling were done daily; blood samples were also taken every 12 min for 6 h on Days 5 and 9, and on Days 6 and 12 of the treatment period in Experiments 1 and 2, respectively. Treatment with estradiol blocked pulsatile LH secretion (P < 0.001). In Experiment 1, implant treatment halted follicular wave emergence between Days 2 and 10. In Experiment 2, follicular waves were suppressed during treatment with estradiol, but resumed following GnRH treatment. In both experiments, the range of peaks in serum FSH concentrations that preceded and triggered follicular wave emergence was almost the same as control ewes and those given estradiol implants alone or with GnRH; mean concentrations did not differ (P < 0.05). We concluded that some level of pulsatile LH secretion was required for the emergence of follicular waves that were triggered by peaks in serum FSH concentrations in the anestrous ewe. (c) 2010 Elsevier Inc. All rights reserved.

Apolipoprotein E4 (1–272) fragment is associated with mitochondrial proteins and affects mitochondrial function in neuronal cells

PubMed Central

Nakamura, Toshiyuki; Watanabe, Atsushi; Fujino, Takahiro; Hosono, Takashi; Michikawa, Makoto

2009-01-01

Background Apolipoprotein E allele ε4 (apoE4) is a strong risk factor for developing Alzheimer's disease (AD). Secreted apoE has a critical function in redistributing lipids among central nervous system cells to maintain normal lipid homeostasis. In addition, previous reports have shown that apoE4 is cleaved by a protease in neurons to generate apoE4(1–272) fragment, which is associated with neurofibrillary tanglelike structures and mitochondria, causing mitochondrial dysfunction. However, it still remains unclear how the apoE fragment associates with mitochondria and induces mitochondrial dysfunction. Results To clarify the molecular mechanism, we carried out experiments to identify intracellular apoE-binding molecules and their functions in modulating mitochondria function. Here, we found that apoE4 binds to ubiquinol cytochrome c reductase core protein 2 (UQCRC2) and cytochrome C1, both of which are components of mitochondrial respiratory complex III, and cytochrome c oxidase subunit 4 isoform 1 (COX IV 1), which is a component of complex IV, in Neuro-2a cells. Interestingly, these proteins associated with apoE4(1–272) more strongly than intact apoE4(1–299). Further analysis showed that in Neuro-2a cells expressing apoE4(1–272), the enzymatic activities of mitochondrial respiratory complexes III and IV were significantly lower than those in Neuro-2a cells expressing apoE4(1–299). Conclusion ApoE4(1–272) fragment expressed in Neuro2a cells is associated with mitochondrial proteins, UQCRC2 and cytochrome C1, which are component of respiratory complex III, and with COX IV 1, which is a member of complex IV. Overexpression of apoE4(1–272) fragment impairs activities of complex III and IV. These results suggest that the C-terminal-truncated fragment of apoE4 binds to mitochondrial complexes and affects their activities, and thereby leading to neurodegeneration. PMID:19695092

The Ethanol-Induced Stimulation of Rat Duodenal Mucosal Bicarbonate Secretion In Vivo Is Critically Dependent on Luminal Cl–

PubMed Central

Sommansson, Anna; Wan Saudi, Wan Salman; Nylander, Olof; Sjöblom, Markus

2014-01-01

Alcohol may induce metabolic and functional changes in gastrointestinal epithelial cells, contributing to impaired mucosal barrier function. Duodenal mucosal bicarbonate secretion (DBS) is a primary epithelial defense against gastric acid and also has an important function in maintaining the homeostasis of the juxtamucosal microenvironment. The aim in this study was to investigate the effects of the luminal perfusion of moderate concentrations of ethanol in vivo on epithelial DBS, fluid secretion and paracellular permeability. Under thiobarbiturate anesthesia, a ∼30-mm segment of the proximal duodenum with an intact blood supply was perfused in situ in rats. The effects on DBS, duodenal transepithelial net fluid flux and the blood-to-lumen clearance of 51Cr-EDTA were investigated. Perfusing the duodenum with isotonic solutions of 10% or 15% ethanol-by-volume for 30 min increased DBS in a concentration-dependent manner, while the net fluid flux did not change. Pre-treatment with the CFTR inhibitor CFTRinh172 (i.p. or i.v.) did not change the secretory response to ethanol, while removing Cl− from the luminal perfusate abolished the ethanol-induced increase in DBS. The administration of hexamethonium (i.v.) but not capsazepine significantly reduced the basal net fluid flux and the ethanol-induced increase in DBS. Perfusing the duodenum with a combination of 1.0 mM HCl and 15% ethanol induced significantly greater increases in DBS than 15% ethanol or 1.0 mM HCl alone but did not influence fluid flux. Our data demonstrate that ethanol induces increases in DBS through a mechanism that is critically dependent on luminal Cl− and partly dependent on enteric neural pathways involving nicotinic receptors. Ethanol and HCl appears to stimulate DBS via the activation of different bicarbonate transporting mechanisms. PMID:25033198

The ethanol-induced stimulation of rat duodenal mucosal bicarbonate secretion in vivo is critically dependent on luminal Cl-.

PubMed

Sommansson, Anna; Wan Saudi, Wan Salman; Nylander, Olof; Sjöblom, Markus

2014-01-01

Alcohol may induce metabolic and functional changes in gastrointestinal epithelial cells, contributing to impaired mucosal barrier function. Duodenal mucosal bicarbonate secretion (DBS) is a primary epithelial defense against gastric acid and also has an important function in maintaining the homeostasis of the juxtamucosal microenvironment. The aim in this study was to investigate the effects of the luminal perfusion of moderate concentrations of ethanol in vivo on epithelial DBS, fluid secretion and paracellular permeability. Under thiobarbiturate anesthesia, a ∼30-mm segment of the proximal duodenum with an intact blood supply was perfused in situ in rats. The effects on DBS, duodenal transepithelial net fluid flux and the blood-to-lumen clearance of 51Cr-EDTA were investigated. Perfusing the duodenum with isotonic solutions of 10% or 15% ethanol-by-volume for 30 min increased DBS in a concentration-dependent manner, while the net fluid flux did not change. Pre-treatment with the CFTR inhibitor CFTRinh172 (i.p. or i.v.) did not change the secretory response to ethanol, while removing Cl- from the luminal perfusate abolished the ethanol-induced increase in DBS. The administration of hexamethonium (i.v.) but not capsazepine significantly reduced the basal net fluid flux and the ethanol-induced increase in DBS. Perfusing the duodenum with a combination of 1.0 mM HCl and 15% ethanol induced significantly greater increases in DBS than 15% ethanol or 1.0 mM HCl alone but did not influence fluid flux. Our data demonstrate that ethanol induces increases in DBS through a mechanism that is critically dependent on luminal Cl- and partly dependent on enteric neural pathways involving nicotinic receptors. Ethanol and HCl appears to stimulate DBS via the activation of different bicarbonate transporting mechanisms.

Phase II Study of a HER-2/neu Intracellular Domain Peptide-Based Vaccine Administered to Stage IV HER2 Positive Breast Cancer Patients Receiving Trastuzumab

DTIC Science & Technology

2010-05-01

7 2 7 3 Lymphopenia 6 2 6 2 Leukocytes 5 1 5 2 Hypocalcemia 5 1 5 2 Fatigue 5 1 4 1 All AE Possibly, Probably, or...been found to have anti-tumor effects in tumor-bearing animals. We assessed the levels of multiple cytokines secreted from PBMN collected 1 month

Interplay between type IV pili activity and exopolysaccharides secretion controls motility patterns in single cells of Myxococcus xanthus

PubMed Central

Hu, Wei; Gibiansky, Maxsim L.; Wang, Jing; Wang, Chuandong; Lux, Renate; Li, Yuezhong; Wong, Gerard C. L.; Shi, Wenyuan

2016-01-01

Myxococcus xanthus performs coordinated social motility of cell groups through the extension and retraction of type IV pili (TFP) on solid surfaces, which requires both TFP and exopolysaccharides (EPS). By submerging cells in a liquid medium containing 1% methylcellulose, M. xanthus TFP-driven motility was induced in isolated cells and independently of EPS. We measured and analyzed the movements of cells using community tracking algorithms, which combine single-cell resolution with statistics from large sample populations. Cells without significant multi-cellular social interactions have surprisingly complex behaviors: EPS− cells exhibited a pronounced increase in the tendency to stand vertically and moved with qualitatively different characteristics than other cells. A decrease in the EPS secretion of cells correlates with a higher instantaneous velocity, but with lower directional persistence in trajectories. Moreover, EPS− cells do not adhere to the surface as strongly as wild-type and EPS overproducing cells, and display a greater tendency to have large deviations between the direction of movement and the cell axis, with cell velocity showing only minimal dependence on the direction of movement. The emerging picture is that EPS does not simply provide rheological resistance to a single mechanism but rather that the availability of EPS impacts motility pattern. PMID:26821939

Brucella Rough Mutant Induce Macrophage Death via Activating IRE1α Pathway of Endoplasmic Reticulum Stress by Enhanced T4SS Secretion

PubMed Central

Li, Peng; Tian, Mingxing; Bao, Yanqing; Hu, Hai; Liu, Jiameng; Yin, Yi; Ding, Chan; Wang, Shaohui; Yu, Shengqing

2017-01-01

Brucella is a Gram-negative facultative intracellular pathogen that causes the worldwide zoonosis, known as brucellosis. Brucella virulence relies mostly on its ability to invade and replicate within phagocytic cells. The type IV secretion system (T4SS) and lipopolysaccharide are two major Brucella virulence factors. Brucella rough mutants reportedly induce the death of infected macrophages, which is T4SS dependent. However, the underlying molecular mechanism remains unclear. In this study, the T4SS secretion capacities of Brucella rough mutant and its smooth wild-type strain were comparatively investigated, by constructing the firefly luciferase fused T4SS effector, BPE123 and VceC. In addition, quantitative real-time PCR and western blotting were used to analyze the T4SS expression. The results showed that T4SS expression and secretion were enhanced significantly in the Brucella rough mutant. We also found that the activity of the T4SS virB operon promoter was notably increased in the Brucella rough mutant, which depends on quorum sensing-related regulators of VjbR upregulation. Cell infection and cell death assays revealed that deletion of vjbR in the Brucella rough mutant absolutely abolished cytotoxicity within macrophages by downregulating T4SS expression. This suggests that up-regulation of T4SS promoted by VjbR in rough mutant ΔrfbE contribute to macrophage death. In addition, we found that the Brucella rough mutant induce macrophage death via activating IRE1α pathway of endoplasmic reticulum stress. Taken together, our study provide evidence that in comparison to the Brucella smooth wild-type strain, VjbR upregulation in the Brucella rough mutant increases transcription of the virB operon, resulting in overexpression of the T4SS gene, accompanied by the over-secretion of effecter proteins, thereby causing the death of infected macrophages via activating IRE1α pathway of endoplasmic reticulum stress, suggesting novel insights into the molecular mechanisms associated with Brucella rough mutant-induced macrophage cytotoxicity. PMID:29021973

Brucella Rough Mutant Induce Macrophage Death via Activating IRE1α Pathway of Endoplasmic Reticulum Stress by Enhanced T4SS Secretion.

PubMed

Li, Peng; Tian, Mingxing; Bao, Yanqing; Hu, Hai; Liu, Jiameng; Yin, Yi; Ding, Chan; Wang, Shaohui; Yu, Shengqing

2017-01-01

Brucella is a Gram-negative facultative intracellular pathogen that causes the worldwide zoonosis, known as brucellosis. Brucella virulence relies mostly on its ability to invade and replicate within phagocytic cells. The type IV secretion system (T4SS) and lipopolysaccharide are two major Brucella virulence factors. Brucella rough mutants reportedly induce the death of infected macrophages, which is T4SS dependent. However, the underlying molecular mechanism remains unclear. In this study, the T4SS secretion capacities of Brucella rough mutant and its smooth wild-type strain were comparatively investigated, by constructing the firefly luciferase fused T4SS effector, BPE123 and VceC. In addition, quantitative real-time PCR and western blotting were used to analyze the T4SS expression. The results showed that T4SS expression and secretion were enhanced significantly in the Brucella rough mutant. We also found that the activity of the T4SS virB operon promoter was notably increased in the Brucella rough mutant, which depends on quorum sensing-related regulators of VjbR upregulation. Cell infection and cell death assays revealed that deletion of vjbR in the Brucella rough mutant absolutely abolished cytotoxicity within macrophages by downregulating T4SS expression. This suggests that up-regulation of T4SS promoted by VjbR in rough mutant Δ rfbE contribute to macrophage death. In addition, we found that the Brucella rough mutant induce macrophage death via activating IRE1α pathway of endoplasmic reticulum stress. Taken together, our study provide evidence that in comparison to the Brucella smooth wild-type strain, VjbR upregulation in the Brucella rough mutant increases transcription of the virB operon, resulting in overexpression of the T4SS gene, accompanied by the over-secretion of effecter proteins, thereby causing the death of infected macrophages via activating IRE1α pathway of endoplasmic reticulum stress, suggesting novel insights into the molecular mechanisms associated with Brucella rough mutant-induced macrophage cytotoxicity.

Recombinant interferon-gamma secreted by Chinese hamster ovary-320 cells cultivated in suspension in protein-free media is protected against extracellular proteolysis by the expression of natural protease inhibitors and by the addition of plant protein hydrolysates to the culture medium.

PubMed

Mols, J; Peeters-Joris, C; Wattiez, R; Agathos, S N; Schneider, Y-J

2005-01-01

Biosafety requirements increasingly restrict the cultivation of mammalian cells producing therapeutic glycoproteins to conditions that are devoid of any compound of animal origin. On cultivation in serum-free media, the proteases inhibitors, usually found in serum, cannot protect secreted recombinant proteins against unwanted endogenous proteolysis. Chinese hamster ovary (CHO) cells, secreting recombinant human interferon-gamma (CHO-320 cell line) and cultivated in suspension in an original protein-free medium, expressed at least two members of the matrix metalloproteinases (MMP), either at the cell surface (proMMP-14 and MMP-14) or secreted (proMMP-9). In addition, tissue- and urinary-type plasminogen activators were also secreted in such culture conditions. At the cell surface, dipeptidyl peptidase IV and tripeptidyl peptidase II (TPPII) activities were also detected, and their activities decreased during time course of batch cultures. The proteolytic activities of these proteins were counterbalanced by (1) their expression as zymogens (proMMP-9, proMMP-14), (2) the expression of their natural inhibitors, tissue inhibitors of metalloproteinases-1 and -2 and plasminogen activator inhibitor-1 (PAI-1), or (3) the addition of plant protein hydrolysates to the culture medium, acting as a nonspecific source of TPPII inhibitors. This study points out that, even in protein-free media, recombinant proteins secreted by CHO cells are actively protected against physiological and unwanted extracellular proteolysis either by endogenous or by exogenous inhibitors.

The type III secretion system is involved in Escherichia coli K1 interactions with Acanthamoeba.

PubMed

Siddiqui, Ruqaiyyah; Malik, Huma; Sagheer, Mehwish; Jung, Suk-Yul; Khan, Naveed Ahmed

2011-08-01

The type III secretion system among Gram-negative bacteria is known to deliver effectors into host cell to interfere with host cellular processes. The type III secretion system in Yersina, Pseudomonas and Enterohemorrhagic Escherichia coli have been well documented to be involved in the bacterial pathogenicity. The existence of type III secretion system has been demonstrated in neuropathogenic E. coli K1 strains. Here, it is observed that the deletion mutant of type III secretion system in E. coli strain EC10 exhibited defects in the invasion and intracellular survival in Acanthamoeba castellanii (a keratitis isolate) compared to its parent strain. Next, it was determined whether type III secretion system plays a role in E. coli K1 survival inside Acanthamoeba during the encystment process. Using encystment assays, our findings revealed that the type III secretion system-deletion mutant exhibited significantly reduced survival inside Acanthamoeba cysts compared with its parent strain, EC10 (P<0.01). This is the first demonstration that the type III secretion system plays an important role in E. coli interactions with Acanthamoeba. A complete understanding of how amoebae harbor bacterial pathogens will help design strategies against E. coli transmission to the susceptible hosts. Copyright © 2011 Elsevier Inc. All rights reserved.

Distribution and diversity of bacterial secretion systems across metagenomic datasets.

PubMed

Barret, Matthieu; Egan, Frank; O'Gara, Fergal

2013-02-01

Bacteria can manipulate their surrounding environment through the secretion of proteins into other living organisms and into the extracellular milieu. In Gram stain negative bacteria this process is mediated by different types of secretion systems from type I through type VI secretion system (T1SS-T6SS). In this study the prevalence of these secretion systems in 312 publicly available microbiomes derived from a wide range of ecosystems was investigated by a gene-centric approach. Our analysis demonstrates that some secretion systems are over-represented in some specific samples. In addition, some T3SS and T6SS phylogenetic clusters were specifically enriched in particular ecological niches, which could indicate specific bacterial adaptation to these environments. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Comparative genomic analysis of Acinetobacter strains isolated from murine colonic crypts.

PubMed

Saffarian, Azadeh; Touchon, Marie; Mulet, Céline; Tournebize, Régis; Passet, Virginie; Brisse, Sylvain; Rocha, Eduardo P C; Sansonetti, Philippe J; Pédron, Thierry

2017-07-11

A restricted set of aerobic bacteria dominated by the Acinetobacter genus was identified in murine intestinal colonic crypts. The vicinity of such bacteria with intestinal stem cells could indicate that they protect the crypt against cytotoxic and genotoxic signals. Genome analyses of these bacteria were performed to better appreciate their biodegradative capacities. Two taxonomically different clusters of Acinetobacter were isolated from murine proximal colonic crypts, one was identified as A. modestus and the other as A. radioresistens. Their identification was performed through biochemical parameters and housekeeping gene sequencing. After selection of one strain of each cluster (A. modestus CM11G and A. radioresistens CM38.2), comparative genomic analysis was performed on whole-genome sequencing data. The antibiotic resistance pattern of these two strains is different, in line with the many genes involved in resistance to heavy metals identified in both genomes. Moreover whereas the operon benABCDE involved in benzoate metabolism is encoded by the two genomes, the operon antABC encoding the anthranilate dioxygenase, and the phenol hydroxylase gene cluster are absent in the A. modestus genomic sequence, indicating that the two strains have different capacities to metabolize xenobiotics. A common feature of the two strains is the presence of a type IV pili system, and the presence of genes encoding proteins pertaining to secretion systems such as Type I and Type II secretion systems. Our comparative genomic analysis revealed that different Acinetobacter isolated from the same biological niche, even if they share a large majority of genes, possess unique features that could play a specific role in the protection of the intestinal crypt.

The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes

PubMed Central

Okkotsu, Yuta; Little, Alexander S.; Schurr, Michael J.

2014-01-01

Pseudomonas aeruginosa is an opportunistic pathogen that causes a multitude of infections. These infections can occur at almost any site in the body and are usually associated with a breach of the innate immune system. One of the prominent sites where P. aeruginosa causes chronic infections is within the lungs of cystic fibrosis patients. P. aeruginosa uses two-component systems that sense environmental changes to differentially express virulence factors that cause both acute and chronic infections. The P. aeruginosa AlgZR two component system is one of its global regulatory systems that affects the organism's fitness in a broad manner. This two-component system is absolutely required for two P. aeruginosa phenotypes: twitching motility and alginate production, indicating its importance in both chronic and acute infections. Additionally, global transcriptome analyses indicate that it regulates the expression of many different genes, including those associated with quorum sensing, type IV pili, type III secretion system, anaerobic metabolism, cyanide and rhamnolipid production. This review examines the complex AlgZR regulatory network, what is known about the structure and function of each protein, and how it relates to the organism's ability to cause infections. PMID:24999454

Helicobacter pylori modulates host cell responses by CagT4SS-dependent translocation of an intermediate metabolite of LPS inner core heptose biosynthesis

PubMed Central

Faber, Eugenia; Bats, Simon H.; Murillo, Tatiana; Speidel, Yvonne; Coombs, Nina

2017-01-01

Highly virulent Helicobacter pylori cause proinflammatory signaling inducing the transcriptional activation and secretion of cytokines such as IL-8 in epithelial cells. Responsible in part for this signaling is the cag pathogenicity island (cagPAI) that codetermines the risk for pathological sequelae of an H. pylori infection such as gastric cancer. The Cag type IV secretion system (CagT4SS), encoded on the cagPAI, can translocate various molecules into cells, the effector protein CagA, peptidoglycan metabolites and DNA. Although these transported molecules are known to contribute to cellular responses to some extent, a major part of the cagPAI-induced signaling leading to IL-8 secretion remains unexplained. We report here that biosynthesis of heptose-1,7-bisphosphate (HBP), an important intermediate metabolite of LPS inner heptose core, contributes in a major way to the H. pylori cagPAI-dependent induction of proinflammatory signaling and IL-8 secretion in human epithelial cells. Mutants defective in the genes required for synthesis of HBP exhibited a more than 95% reduction of IL-8 induction and impaired CagT4SS-dependent cellular signaling. The loss of HBP biosynthesis did not abolish the ability to translocate CagA. The human cellular adaptor TIFA, which was described before to mediate HBP-dependent activity in other Gram-negative bacteria, was crucial in the cagPAI- and HBP pathway-induced responses by H. pylori in different cell types. The active metabolite was present in H. pylori lysates but not enriched in bacterial supernatants. These novel results advance our mechanistic understanding of H. pylori cagPAI-dependent signaling mediated by intracellular pattern recognition receptors. They will also allow to better dissect immunomodulatory activities by H. pylori and to improve the possibilities of intervention in cagPAI- and inflammation-driven cancerogenesis. PMID:28715499

The mutagenesis of a type IV secretion system locus of Piscirickettsia salmonis leads to the attenuation of the pathogen in Atlantic salmon, Salmo salar.

PubMed

Mancilla, M; Saavedra, J; Grandón, M; Tapia, E; Navas, E; Grothusen, H; Bustos, P

2018-04-01

Piscirickettsiosis is a threatening infectious disease for the salmon industry, due to it being responsible for significant economic losses. The control of outbreaks also poses considerable environmental challenges. Despite Piscirickettsia salmonis having been discovered as the aetiological agent of the disease more than 25 years ago, its pathogenicity remains poorly understood. Among virulence factors identified so far, type four secretion systems (T4SS) seem to play a key role during the infection caused by the bacterium. We report here the genetic manipulation of P. salmonis by means of the transference of plasmid DNA in mating assays. An insertion cassette was engineered for targeting the icmB gene, which encodes a putative T4SS-ATPase and is carried by one of the chromosomal T4SS clusters found within the genome of P. salmonis PM15972A1, a virulent representative of the EM-90-like strain. The molecular characterization of the resulting mutant strain demonstrated that the insertion interrupted the target gene. Further in vitro testing of the icmB mutant showed a dramatic drop in infectivity as tested in CHSE-214 cells, which is in agreement with its attenuated behaviour observed in vivo. Altogether, our results demonstrate that, similar to other facultative intracellular pathogens, P. salmonis' virulence relies on an intact T4SS. © 2017 The Authors. Journal of Fish Diseases Published by John Wiley & Sons Ltd.

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

Nagamatsu, Shinya, E-mail: shinya@ks.kyorin-u.ac.jp; Ohara-Imaizumi, Mica; Nakamichi, Yoko

Highlights: {yields} Anti-diabetic new drug, DPP-4 inhibitor, can affect the insulin exocytosis. {yields} DPP-4 inhibitor treatment altered syntaxin 1 expression. {yields} Treatment of db/db mice with DPP-4 inhibitor increased insulin release. -- Abstract: Incretin promotes insulin secretion acutely. Recently, orally-administered DPP-4 inhibitors represent a new class of anti-hyperglycemic agents. Indeed, inhibitors of dipeptidyl peptidase-IV (DPP-4), sitagliptin, has just begun to be widely used as therapeutics for type 2 diabetes. However, the effects of sitagliptin-treatment on insulin exocytosis from single {beta}-cells are yet unknown. We therefore investigated how sitagliptin-treatment in db/db mice affects insulin exocytosis by treating db/db mice with des-F-sitagliptinmore » for 2 weeks. Perfusion studies showed that 2 weeks-sitagliptin treatment potentiated insulin secretion. We then analyzed insulin granule motion and SNARE protein, syntaxin 1, by TIRF imaging system. TIRF imaging of insulin exocytosis showed the increased number of docked insulin granules and increased fusion events from them during first-phase release. In accord with insulin exocytosis data, des-F-sitagliptin-treatment increased the number of syntaxin 1 clusters on the plasma membrane. Thus, our data demonstrated that 2-weeks des-F-sitagliptin-treatment increased the fusion events of insulin granules, probably via increased number of docked insulin granules and that of syntaxin 1 clusters.« less

Multipronged regulatory functions of a novel endonuclease (TieA) from Helicobacter pylori

PubMed Central

Devi, Savita; Ansari, Suhail A.; Tenguria, Shivendra; Kumar, Naveen; Ahmed, Niyaz

2016-01-01

Helicobacter pylori portrays a classical paradigm of persistent bacterial infections. A well balanced homeostasis of bacterial effector functions and host responses is purported to be the key in achieving long term colonization in specific hosts. H. pylori nucleases have been shown to assist in natural transformation, but their role in virulence and colonization remains elusive. Therefore, it is imperative to understand the involvement of these nucleases in the pathogenesis of H. pylori. Here, we report the multifaceted role of a TNFR-1 interacting endonuclease A (TieA) from H. pylori. tieA expression is differentially regulated in response to environmental stress and post adherence to gastric epithelial cells. Studies with isogenic knockouts of tieA revealed it to be a secretory protein which translocates into the host gastric epithelial cells independent of a type IV secretion system, gets phosphorylated by DNA-PK kinase and auto-phosphorylates as serine kinase. Furthermore, TieA binds to and cleaves DNA in a non-specific manner and promotes Fas mediated apoptosis in AGS cells. Additionally, TieA induced pro-inflammatory cytokine secretion via activation of transcription factor AP-1 and signaled through MAP kinase pathway. Collectively, TieA with its multipronged and moonlighting functions could facilitate H. pylori in maintaining a balance of bacterial adaptation, and elimination by the host responses. PMID:27550181

In vitro modulation of inflammatory target gene expression by a polyphenol-enriched fraction of rose oil distillation waste water.

PubMed

Wedler, Jonas; Weston, Anna; Rausenberger, Julia; Butterweck, Veronika

2016-10-01

Classical production of rose oil is based on water steam distillation from the flowers of Rosa damascena. During this process, large quantities of waste water accrue which are discharged to the environment, causing severe pollution of both, groundwater and surface water due to a high content of polyphenols. We recently developed a strategy to purify the waste water into a polyphenol-depleted and a polyphenol-enriched fraction RF20-(SP-207). RF20-(SP-207) and sub-fraction F(IV) significantly inhibited cell proliferation and migration of HaCaT cells. Since there is a close interplay between these actions and inflammatory processes, here we focused on the fractions' influence on pro-inflammatory biomarkers. HaCaT keratinocytes were treated with RF20-(SP-207), F(IV) (both at 50μg/mL) and ellagic acid (10μM) for 24h under TNF-α (20ng/mL) stimulated and non-stimulated conditions. Gene expression of IL-1β, IL-6, IL-8, RANTES and MCP-1 was analyzed by reverse transcriptase polymerase chain reaction (RT-PCR) and cellular protein secretion of IL-8, RANTES and MCP-1 was determined by ELISA based assays. RF20-(SP-207) and F(IV) significantly decreased the expression and cellular protein secretion of IL-1β, IL-6, IL-8, RANTES and MCP-1. The diminishing effects on inflammatory target gene expression were slightly less pronounced under TNF-α stimulated conditions. In conclusion, the recovered polyphenol fraction RF20-(SP-207) from rose oil distillation waste water markedly modified inflammatory target gene expression in vitro, and, therefore, could be further developed as alternative treatment of acute and chronic inflammation. Copyright © 2016 Elsevier B.V. All rights reserved.

Plasma progesterone levels and luteal activity during gestation and prolonged oviductal egg retention in a tropical lizard, Calotes versicolor.

PubMed

Shanbhag, B A; Radder, R S; Saidapur, S K

2001-07-01

Plasma progesterone (P) levels and luteal and adrenal activities were studied during normal gestation and unusual prolonged period of oviductal egg retention in a polyautochronic, multiclutched lizard, Calotes versicolor. The normal gestation period (approximately 15 days) was categorized into four stages: stage I--a few hours following ovulation, stage II--eggs with shell and embryo at primitive streak, stage III--embryonic stages 16-20, and stage IV--prior to ovipostion (stages 26-27). The gravid lizards maintained in captivity retained eggs in their oviducts for 45 days. Plasma P levels were low in stage I, increased significantly during stage II, declined in stage III, and reached their lowest in stage IV of gestation. 3Beta-hydroxysteroid dehydrogenase (3beta-HSDH) activity was greater in lutein cells at stage II and was present in traces in stage IV gestation. Interestingly, plasma P titers that were high in lizards with eggs retained longer though the corpora lutea (CL) showed a trace 3beta-HSDH activity. However, 3beta-HSDH activity was greater in the adrenocortical cells in these lizards than that in lizards during a normal gestation period. The present study on C. versicolor shows that the CL remains active and secretes P only during the early part of the gestation. The drop in P level during the later part of gestation might facilitate growth of a second set of vitellogenic follicles. During unfavorable conditions when the lizards are forced to retain eggs in the oviduct, the adrenal glands seem to secrete progesterone to help in egg retention and in inhibition of oviposition.

Oncogenic osteomalacia due to FGF23-expressing colon adenocarcinoma.

PubMed

Leaf, David E; Pereira, Renata C; Bazari, Hasan; Jüppner, Harald

2013-03-01

Oncogenic osteomalacia, a paraneoplastic syndrome associated with hypophosphatemia due to increased urinary phosphate excretion, is caused by excessive synthesis and secretion of fibroblast growth factor 23 (FGF23), a phosphaturic hormone that is normally produced by osteocytes. Most cases of oncogenic osteomalacia have been associated with benign tumors of bone or soft tissue; however, whether malignant neoplasms can also produce and secrete FGF23 is currently unknown. The aim was to determine whether a malignant neoplasm could cause oncogenic osteomalacia through excessive production and secretion of FGF23. We describe an 80-year-old woman with stage IV colon adenocarcinoma who presented with severe hypophosphatemia (0.4 mg/dL; reference, 2.6-4.5 mg/dL). Fractional excretion of phosphate was 34% (reference, <5% in the setting of hypophosphatemia), and plasma levels of FGF23 were highly elevated at 674 RU/mL (reference, <180 RU/mL). Immunohistochemical analysis of the patient's tumor showed strong staining for FGF23. Genetic analyses revealed a point mutation in the KRAS gene. We present the first case in which a malignant neoplasm is documented to produce and secrete FGF23, leading to renal phosphate-wasting. Oncogenic osteomalacia should be considered in the differential diagnosis for patients with a malignant tumor who present with hypophosphatemia.

Oncogenic Osteomalacia due to FGF23-Expressing Colon Adenocarcinoma

PubMed Central

Pereira, Renata C.; Bazari, Hasan; Jüppner, Harald

2013-01-01

Context: Oncogenic osteomalacia, a paraneoplastic syndrome associated with hypophosphatemia due to increased urinary phosphate excretion, is caused by excessive synthesis and secretion of fibroblast growth factor 23 (FGF23), a phosphaturic hormone that is normally produced by osteocytes. Most cases of oncogenic osteomalacia have been associated with benign tumors of bone or soft tissue; however, whether malignant neoplasms can also produce and secrete FGF23 is currently unknown. Objective: The aim was to determine whether a malignant neoplasm could cause oncogenic osteomalacia through excessive production and secretion of FGF23. Setting: We describe an 80-year-old woman with stage IV colon adenocarcinoma who presented with severe hypophosphatemia (0.4 mg/dL; reference, 2.6–4.5 mg/dL). Results: Fractional excretion of phosphate was 34% (reference, <5% in the setting of hypophosphatemia), and plasma levels of FGF23 were highly elevated at 674 RU/mL (reference, <180 RU/mL). Immunohistochemical analysis of the patient's tumor showed strong staining for FGF23. Genetic analyses revealed a point mutation in the KRAS gene. Conclusions: We present the first case in which a malignant neoplasm is documented to produce and secrete FGF23, leading to renal phosphate-wasting. Oncogenic osteomalacia should be considered in the differential diagnosis for patients with a malignant tumor who present with hypophosphatemia. PMID:23393166

Bioactive compounds from culinary herbs inhibit a molecular target for type 2 diabetes management, dipeptidyl peptidase IV.

PubMed

Bower, Allyson M; Real Hernandez, Luis M; Berhow, Mark A; de Mejia, Elvira Gonzalez

2014-07-02

Greek oregano (Origanum vulgare), marjoram (Origanum majorana), rosemary (Rosmarinus officinalis), and Mexican oregano (Lippia graveolens) are concentrated sources of bioactive compounds. The aims were to characterize and examine extracts from greenhouse-grown or commercially purchased herbs for their ability to inhibit dipeptidyl peptidase IV (DPP-IV) and protein tyrosine phosphatase 1B (PTP1B), enzymes that play a role in insulin secretion and insulin signaling, respectively. Greenhouse herbs contained more polyphenols (302.7-430.1 μg of gallic acid equivalents/mg of dry weight of extract (DWE)) and flavonoids (370.1-661.4 μg of rutin equivalents/mg of DWE) compared to the equivalent commercial herbs. Greenhouse rosemary, Mexican oregano, and marjoram extracts were the best inhibitors of DPP-IV (IC₅₀=16, 29, and 59 μM, respectively). Commercial rosemary, Mexican oregano, and marjoram were the best inhibitors of PTP1B (32.4-40.9% at 500 μM). The phytochemicals eriodictyol, naringenin, hispidulin, cirsimaritin, and carnosol were identified by LC-ESI-MS as being present in greenhouse-grown Mexican oregano and rosemary. Computational modeling indicated that hispidulin, carnosol, and eriodictyol would have the best binding affinities for DPP-IV. Biochemically, the best inhibitors of DPP-IV were cirsimaritin (IC₅₀=0.43±0.07 μM), hispidulin (IC₅₀=0.49±0.06 μM), and naringenin (IC₅₀=2.5±0.29 μM). Overall, herbs contain several flavonoids that inhibit DPP-IV and should be investigated further regarding their potential in diabetes management.

The Human Antimicrobial Protein Calgranulin C Participates in Control of Helicobacter pylori Growth and Regulation of Virulence.

PubMed

Haley, Kathryn P; Delgado, Alberto G; Piazuelo, M Blanca; Mortensen, Brittany L; Correa, Pelayo; Damo, Steven M; Chazin, Walter J; Skaar, Eric P; Gaddy, Jennifer A

2015-07-01

During infectious processes, antimicrobial proteins are produced by both epithelial cells and innate immune cells. Some of these antimicrobial molecules function by targeting transition metals and sequestering these metals in a process referred to as "nutritional immunity." This chelation strategy ultimately starves invading pathogens, limiting their growth within the vertebrate host. Recent evidence suggests that these metal-binding antimicrobial molecules have the capacity to affect bacterial virulence, including toxin secretion systems. Our previous work showed that the S100A8/S100A9 heterodimer (calprotectin, or calgranulin A/B) binds zinc and represses the elaboration of the H. pylori cag type IV secretion system (T4SS). However, there are several other S100 proteins that are produced in response to infection. We hypothesized that the zinc-binding protein S100A12 (calgranulin C) is induced in response to H. pylori infection and also plays a role in controlling H. pylori growth and virulence. To test this, we analyzed gastric biopsy specimens from H. pylori-positive and -negative patients for S100A12 expression. These assays showed that S100A12 is induced in response to H. pylori infection and inhibits bacterial growth and viability in vitro by binding nutrient zinc. Furthermore, the data establish that the zinc-binding activity of the S100A12 protein represses the activity of the cag T4SS, as evidenced by the gastric cell "hummingbird" phenotype, interleukin 8 (IL-8) secretion, and CagA translocation assays. In addition, high-resolution field emission gun scanning electron microscopy (FEG-SEM) was used to demonstrate that S100A12 represses biogenesis of the cag T4SS. Together with our previous work, these data reveal that multiple S100 proteins can repress the elaboration of an oncogenic bacterial surface organelle. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Fetal Hypothalamus-Pituitary-Adrenal Responses to Estradiol Sulfate

PubMed Central

2011-01-01

Estradiol (E2) is an important modifier of the activity of the fetal hypothalamus-pituitary-adrenal axis. We have reported that estradiol-3-sulfate (E2SO4) circulates in fetal blood in far higher concentrations than E2 and that the fetal brain expresses steroid sulfatase, required for local deconjugation of E2SO4. We performed the present study to test the hypothesis that chronic infusion of E2SO4 chronically increases ACTH and cortisol secretion and that it shortens gestation. Chronically catheterized fetal sheep were treated with E2SO4 intracerebroventricular (n = 5), E2SO4 iv (n = 4), or no steroid infusion (control group, n = 5). Fetuses were subjected to arterial blood sampling every other day until spontaneous birth for plasma hormone analysis. Treatment with E2SO4 attenuated preparturient increases in ACTH secretion near term without affecting the ontogenetic rise in plasma cortisol. Infusion of E2SO4 intracerebroventricularly significantly increased plasma E2, plasma E2SO4, and plasma progesterone and shortened gestation compared with all other groups. These results are consistent with the conclusion that E2SO4: 1) interacts with the hypothalamus-pituitary-adrenal axis primarily by stimulating cortisol secretion and inhibiting ACTH and pro-ACTH secretion by negative feedback; and 2) stimulates the secretion of E2 and E2SO4. We conclude that the endocrine response to E2SO4 in the fetus is not identical with the response to E2. PMID:21952234

The enteric nervous system modulates mammalian duodenal mucosal bicarbonate secretion.

PubMed

Hogan, D L; Yao, B; Steinbach, J H; Isenberg, J I

1993-08-01

Interaction of the enteric nerves in regulating mammalian duodenal mucosal bicarbonate secretion is not well understood. The purpose of the present experiments was to evaluate the role of the enteric nervous system on bicarbonate secretion from rabbit duodenal mucosa in vitro. Proximal duodenum from male New Zealand White rabbits was stripped of seromuscular layers, mounted in Ussing chambers, and studied under short-circuited conditions. Effects of electrical field stimulation, vasoactive intestinal polypeptide (VIP), carbachol, prostaglandin E2 (PGE2), dibutyryl-cyclic adenosine monophosphate (db-cAMP), and the neurotoxin tetrodotoxin (TTX) and muscarinic blockade by atropine were studied. Electrical field stimulation significantly (P < 0.01) stimulated bicarbonate secretion, short-circuit current (Isc), and electrical potential difference (PD) that was sensitive to both TTX and atropine. VIP-stimulated bicarbonate secretion was significantly inhibited by TTX (-73%), yet Isc and PD remained unchanged. Atropine decreased VIP-induced bicarbonate secretion (-69%) and Isc (-43%). Carbachol-stimulated bicarbonate secretion, Isc, and PD were abolished by atropine, whereas TTX was without affect. Neither TTX nor atropine had a significant effect on PGE2 or db-cAMP-stimulated bicarbonate secretion. These results suggest that (1) enteric nerve stimulation activates an acetylcholine receptor that in turn stimulates duodenal epithelial bicarbonate secretion; (2) VIP stimulates bicarbonate secretion, in large part, via the enteric nervous system; and (3) PGE2 and cAMP stimulate bicarbonate secretion independent of the enteric nervous system.

Novel mechanisms power bacterial gliding motility.

PubMed

Nan, Beiyan; Zusman, David R

2016-07-01

For many bacteria, motility is essential for survival, growth, virulence, biofilm formation and intra/interspecies interactions. Since natural environments differ, bacteria have evolved remarkable motility systems to adapt, including swimming in aqueous media, and swarming, twitching and gliding on solid and semi-solid surfaces. Although tremendous advances have been achieved in understanding swimming and swarming motilities powered by flagella, and twitching motility powered by Type IV pili, little is known about gliding motility. Bacterial gliders are a heterogeneous group containing diverse bacteria that utilize surface motilities that do not depend on traditional flagella or pili, but are powered by mechanisms that are less well understood. Recently, advances in our understanding of the molecular machineries for several gliding bacteria revealed the roles of modified ion channels, secretion systems and unique machinery for surface movements. These novel mechanisms provide rich source materials for studying the function and evolution of complex microbial nanomachines. In this review, we summarize recent findings made on the gliding mechanisms of the myxobacteria, flavobacteria and mycoplasmas. © 2016 John Wiley & Sons Ltd.

Identification of genes encoding the type IX secretion system and secreted proteins in Flavobacterium columnare IA-S-4

USDA-ARS?s Scientific Manuscript database

Flavobacterium columnare, a member of the phylum Bacteroidetes, causes columnaris disease in wild and aquaculture-reared freshwater fish. The mechanisms responsible for columnaris disease are not known. Many members of the phylum Bacteroidetes use type IX secretion systems (T9SSs) to secrete enzymes...

Baseline Goblet Cell Mucin Secretion in the Airways Exceeds Stimulated Secretion over Extended Time Periods, and Is Sensitive to Shear Stress and Intracellular Mucin Stores

PubMed Central

Doyle, Sean P.; Nguyen, Kristine; Ribeiro, Carla M. P.; Vasquez, Paula A.; Forest, M. Gregory; Lethem, Michael I.; Dickey, Burton F.; Davis, C. William

2015-01-01

Airway mucin secretion studies have focused on goblet cell responses to exogenous agonists almost to the exclusion of baseline mucin secretion (BLMS). In human bronchial epithelial cell cultures (HBECCs), maximal agonist-stimulated secretion exceeds baseline by ~3-fold as measured over hour-long periods, but mucin stores are discharged completely and require 24 h for full restoration. Hence, over 24 h, total baseline exceeds agonist-induced secretion by several-fold. Studies with HBECCs and mouse tracheas showed that BLMS is highly sensitive to mechanical stresses. Harvesting three consecutive 1 h baseline luminal incubations with HBECCs yielded equal rates of BLMS; however, lengthening the middle period to 72 h decreased the respective rate significantly, suggesting a stimulation of BLMS by the gentle washes of HBECC luminal surfaces. BLMS declined exponentially after washing HBECCs (t1/2 = 2.75 h), to rates approaching zero. HBECCs exposed to low perfusion rates exhibited spike-like increases in BLMS when flow was jumped 5-fold: BLMS increased >4 fold, then decreased within 5 min to a stable plateau at 1.5–2-fold over control. Higher flow jumps induced proportionally higher BLMS increases. Inducing mucous hyperplasia in HBECCs increased mucin production, BLMS and agonist-induced secretion. Mouse tracheal BLMS was ~6-fold higher during perfusion, than when flow was stopped. Munc13-2 null mouse tracheas, with their defect of accumulated cellular mucins, exhibited similar BLMS as WT, contrary to predictions of lower values. Graded mucous metaplasia induced in WT and Munc13-2 null tracheas with IL-13, caused proportional increases in BLMS, suggesting that naïve Munc13-2 mouse BLMS is elevated by increased mucin stores. We conclude that BLMS is, [i] a major component of mucin secretion in the lung, [ii] sustained by the mechanical activity of a dynamic lung, [iii] proportional to levels of mucin stores, and [iv] regulated differentially from agonist-induced mucin secretion. PMID:26024524

Effect of arginine on the GHRH-stimulated GH secretion in patients with hyperthyroidism.

PubMed

Giustina, A; Schettino, M; Bussi, A R; Legati, F; Licini, M; Zuccato, F; Wehrenberg, W B

1992-01-01

Patients with hyperthyroidism have reduced GH responses to pharmacological stimuli and reduced spontaneous nocturnal GH secretion. The stimulatory effect of arginine on GH secretion has been suggested to depend on a decrease in hypothalamic somatostatin tone. The aim of our study was to evaluate the effects of arginine on the GH-releasing hormone (GHRH)-stimulated GH secretion in patients with hyperthyroidism. Six hyperthyroid patients with recent diagnosis of Graves' disease [mean age +/- SEM, 39.2 +/- 1.4 years; body mass index (BMI) 22 +/- 0.4 kg/m2] and 6 healthy nonobese volunteers (4 males, 2 females; mean age +/- SEM, 35 +/- 3.5 years) underwent two experimental trials at no less than 7-day intervals: GHRH (100 micrograms, i.v.)-induced GH secretion was evaluated after 30 min i.v. infusion of saline (100 ml) or arginine (30 g) in 100 ml of saline. Hyperthyroid patients showed blunted GH peaks after GHRH (13.2 +/- 2.9 micrograms/l) as compared with normal subjects (23.8 +/- 3.9 micrograms/l, p < 0.05). GH peaks after GHRH were only slightly enhanced by arginine in hyperthyroid subjects (17.6 +/- 2.9 micrograms/l), whereas, in normal subjects, the enhancement was clear cut (36.6 +/- 4.4 micrograms/l; p < 0.05). GH values after arginine + GHRH were still lower in hyperthyroid patients with respect to normal subjects. Our data demonstrate that arginine enhances but does not normalize the GH response to GHRH in patients with hyperthyroidism when compared with normal subjects. We hypothesize that hyperthyroxinemia may decrease GH secretion, both increasing somatostatin tone and acting directly at the pituitary level.

Pseudomonas aeruginosa proteolytically alters the interleukin 22-dependent lung mucosal defense.

PubMed

Guillon, Antoine; Brea, Deborah; Morello, Eric; Tang, Aihua; Jouan, Youenn; Ramphal, Reuben; Korkmaz, Brice; Perez-Cruz, Magdiel; Trottein, Francois; O'Callaghan, Richard J; Gosset, Philippe; Si-Tahar, Mustapha

2017-08-18

The IL-22 signaling pathway is critical for regulating mucosal defense and limiting bacterial dissemination. IL-22 is unusual among interleukins because it does not directly regulate the function of conventional immune cells, but instead targets cells at outer body barriers, such as respiratory epithelial cells. Consequently, IL-22 signaling participates in the maintenance of the lung mucosal barrier by controlling cell proliferation and tissue repair, and enhancing the production of specific chemokines and anti-microbial peptides. Pseudomonas aeruginosa is a major pathogen of ventilator-associated pneumonia and causes considerable lung tissue damage. A feature underlying the pathogenicity of this bacterium is its capacity to persist and develop in the host, particularly in the clinical context of nosocomial lung infections. We aimed to investigate the ability of P. auruginosa to disrupt immune-epithelial cells cross-talk. We found that P. aeruginosa escapes the host mucosal defenses by degrading IL-22, leading to severe inhibition of IL-22-mediated immune responses. We demonstrated in vitro that, protease IV, a type 2 secretion system-dependent serine protease, is responsible for the degradation of IL-22 by P. aeruginosa. Moreover, the major anti-proteases molecules present in the lungs were unable to inhibit protease IV enzymatic activity. In addition, tracheal aspirates of patients infected by P. aeruginosa contain protease IV activity which further results in IL-22 degradation. This so far undescribed cleavage of IL-22 by a bacterial protease is likely to be an immune-evasion strategy that contributes to P. aeruginosa-triggered respiratory infections.

Two distinct secretion systems facilitate tissue invasion by the rice blast fungus Magnaporthe oryzae

PubMed Central

Giraldo, Martha C.; Dagdas, Yasin F.; Gupta, Yogesh K.; Mentlak, Thomas A.; Yi, Mihwa; Martinez-Rocha, Ana Lilia; Saitoh, Hiromasa; Terauchi, Ryohei; Talbot, Nicholas J.; Valent, Barbara

2013-01-01

To cause plant diseases, pathogenic micro-organisms secrete effector proteins into host tissue to suppress immunity and support pathogen growth. Bacterial pathogens have evolved several distinct secretion systems to target effector proteins, but whether fungi, which cause the major diseases of most crop species, also require different secretory mechanisms is not known. Here we report that the rice blast fungus Magnaporthe oryzae possesses two distinct secretion systems to target effectors during plant infection. Cytoplasmic effectors, which are delivered into host cells, preferentially accumulate in the biotrophic interfacial complex, a novel plant membrane-rich structure associated with invasive hyphae. We show that the biotrophic interfacial complex is associated with a novel form of secretion involving exocyst components and the Sso1 t-SNARE. By contrast, effectors that are secreted from invasive hyphae into the extracellular compartment follow the conventional secretory pathway. We conclude that the blast fungus has evolved distinct secretion systems to facilitate tissue invasion. PMID:23774898

Protein-Phospholipid Interactions in Nonclassical Protein Secretion: Problem and Methods of Study

PubMed Central

Prudovsky, Igor; Kumar, Thallapuranam Krishnaswamy Suresh; Sterling, Sarah; Neivandt, David

2013-01-01

Extracellular proteins devoid of signal peptides use nonclassical secretion mechanisms for their export. These mechanisms are independent of the endoplasmic reticulum and Golgi. Some nonclassically released proteins, particularly fibroblast growth factors (FGF) 1 and 2, are exported as a result of their direct translocation through the cell membrane. This process requires specific interactions of released proteins with membrane phospholipids. In this review written by a cell biologist, a structural biologist and two membrane engineers, we discuss the following subjects: (i) Phenomenon of nonclassical protein release and its biological significance; (ii) Composition of the FGF1 multiprotein release complex (MRC); (iii) The relationship between FGF1 export and acidic phospholipid externalization; (iv) Interactions of FGF1 MRC components with acidic phospholipids; (v) Methods to study the transmembrane translocation of proteins; (vi) Membrane models to study nonclassical protein release. PMID:23396106

Roles of silkworm endoplasmic reticulum chaperones in the secretion of recombinant proteins expressed by baculovirus system.

PubMed

Imai, Saki; Kusakabe, Takahiro; Xu, Jian; Li, Zhiqing; Shirai, Shintaro; Mon, Hiroaki; Morokuma, Daisuke; Lee, Jae Man

2015-11-01

Baculovirus expression vector system (BEVS) is widely used for production of recombinant eukaryotic proteins in insect larvae or cultured cells. BEVS has advantages over bacterial expression system in producing post-translationally modified secreted proteins. However, for some unknown reason, it is very difficult for insects to secrete sufficiently for certain proteins of interest. To understand the reasons why insect cells fail to secrete some kinds of recombinant proteins, we here employed three mammalian proteins as targets, EPO, HGF, and Wnt3A, with different secretion levels in BEVS and investigated their mRNA transcriptions from the viral genome, subcellular localizations, and interactions with silkworm ER chaperones. Moreover, we observed that no significantly influence on the secretion amounts of all three proteins when depleting or overexpressing most endogenous ER chaperone genes in cultured silkworm cells. However, among all detected ER chaperones, the depletion of BiP severely decreased the recombinant protein secretion in BEVS, indicating the possible central role of Bip in silkworm secretion pathway.

Physical exercise introduced after weaning enhances pancreatic islet responsiveness to glucose and potentiating agents in adult MSG-obese rats.

PubMed

Ribeiro, R A; Bonfleur, M L; Vanzela, E C; Zotti, A I; Scomparin, D X; Boschero, A C; Balbo, S L

2014-08-01

Physical exercise represents an alternative way to prevent and/or ameliorate chronic metabolic diseases. Disruption of sympathetic nervous system (SNS) activity contributes to adiposity in obese subjects. Here, we verified the preventive effect of swimming training upon adiposity, adrenal catecholamine storage, and pancreatic islet function in obese monosodium glutamate (MSG)-treated rats. Male neonatal Wistar rats received MSG (4 mg/g body weight) during the first 5 days of life and, at weaning, half of the rats were submitted to swimming training, 30 min/day, 3 days a week, until 90 days of age (exercised rats: MSGex). Half of the rats were used as controls (sedentary group, MSGsd). Exercise training (ET) decreased insulinemia and fat deposition in MSGex, and increased adrenal catecholamine content, compared with MSGsd rats. Insulinemia during the ivGTT was lower in MSGex rats, despite a lack of difference in glycemia. Swimming training enhanced insulin release in islets challenged by 2.8-8.3 mmol/l glucose, whereas, at supraphysiological glucose concentrations (11.1-16.7 mmol/l), MSGex islets secreted less insulin than MSGsd. No differences in insulin secretion were observed following l-arginine (Arg) or K(+) stimuli. In contrast, islets from MSGex rats secreted more insulin when exposed to carbachol (100 μmol/l), forskolin (10 μmol/l), or IBMX (1 mmol/l) at 8.3 mmol/l glucose. Additionally, MSGex islets presented a better epinephrine inhibition upon insulin release. These results demonstrate that ET prevented the onset of obesity in MSG rats, probably by enhancing adrenal catecholamine levels. ET ameliorates islet responsiveness to several compounds, as well as insulin peripheral action. © Georg Thieme Verlag KG Stuttgart · New York.

System Specificity of the TpsB Transporters of Coexpressed Two-Partner Secretion Systems of Neisseria meningitidis

PubMed Central

ur Rahman, Sadeeq

2013-01-01

The two-partner secretion (TPS) systems of Gram-negative bacteria consist of a large secreted exoprotein (TpsA) and a transporter protein (TpsB) located in the outer membrane. TpsA targets TpsB for transport across the membrane via its ∼30-kDa TPS domain located at its N terminus, and this domain is also the minimal secretory unit. Neisseria meningitidis genomes encode up to five TpsAs and two TpsBs. Sequence alignments of TPS domains suggested that these are organized into three systems, while there are two TpsBs, which raised questions on their system specificity. We show here that the TpsB2 transporter of Neisseria meningitidis is able to secrete all types of TPS domains encoded in N. meningitidis and the related species Neisseria lactamica but not domains of Haemophilus influenzae and Pseudomonas aeruginosa. In contrast, the TpsB1 transporter seemed to be specific for its cognate N. meningitidis system and did not secrete the TPS domains of other meningococcal systems. However, TpsB1 did secrete the TPS2b domain of N. lactamica, which is related to the meningococcal TPS2 domains. Apparently, the secretion depends on specific sequences within the TPS domain rather than the overall TPS domain structure. PMID:23222722

Insulin and C-peptide secretion in non-obese patients with polycystic ovarian disease.

PubMed

Mahabeer, S; Jialal, I; Norman, R J; Naidoo, C; Reddi, K; Joubert, S M

1989-09-01

Plasma glucose, immunoreactive insulin (IRI) and C-peptide responses during an oral glucose tolerance test (oGTT) were assessed in 11 non-obese patients with polycystic ovarian disease (PCOD) and 11 reference subjects matched for age, height and weight. Also, 6 patients with PCOD and 6 normal women were subjected to intravenous glucose tolerance testing (ivGTT) On oGTT, all subjects exhibited normal glucose tolerance; however, PCOD patients had significantly higher mean plasma glucose levels at 30, 60, 90 and 120 min and higher mean incremental glucose areas. In addition the patients with polycystic ovaries showed higher mean basal IRI and C-peptide levels, higher mean glucose stimulated IRI and C-peptide levels and higher mean incremental IRI and C-peptide values. The molar ratios of C-peptide/IRI were significantly lower in the PCOD group at all time intervals after glucose stimulation when compared to the normal women. During ivGTT, there were significantly higher mean glucose levels at 5, 40, 50 and 60 min in the PCOD group when compared to the reference group. The IRI response to intravenous glucose in the PCOD women was similar to the reference group. The findings on oGTT suggest that non-obese patients with PCOD have increased pancreatic IRI secretion as well as impaired hepatic extraction of the hormone.

The structural genes for three Drosophila glue proteins reside at a single polytene chromosome puff locus.

PubMed Central

Crowley, T E; Bond, M W; Meyerowitz, E M

1983-01-01

The polytene chromosome puff at 68C on the Drosophila melanogaster third chromosome is thought from genetic experiments to contain the structural gene for one of the secreted salivary gland glue polypeptides, sgs-3. Previous work has demonstrated that the DNA included in this puff contains sequences that are transcribed to give three different polyadenylated RNAs that are abundant in third-larval-instar salivary glands. These have been called the group II, group III, and group IV RNAs. In the experiments reported here, we used the nucleotide sequence of the DNA coding for these RNAs to predict some of the physical and chemical properties expected of their protein products, including molecular weight, amino acid composition, and amino acid sequence. Salivary gland polypeptides with molecular weights similar to those expected for the 68C RNA translation products, and with the expected degree of incorporation of different radioactive amino acids, were purified. These proteins were shown by amino acid sequencing to correspond to the protein products of the 68C RNAs. It was further shown that each of these proteins is a part of the secreted salivary gland glue: the group IV RNA codes for the previously described sgs-3, whereas the group II and III RNAs code for the newly identified glue polypeptides sgs-8 and sgs-7. Images PMID:6406838

DBSecSys 2.0: a database of Burkholderia mallei and Burkholderia pseudomallei secretion systems.

PubMed

Memišević, Vesna; Kumar, Kamal; Zavaljevski, Nela; DeShazer, David; Wallqvist, Anders; Reifman, Jaques

2016-09-20

Burkholderia mallei and B. pseudomallei are the causative agents of glanders and melioidosis, respectively, diseases with high morbidity and mortality rates. B. mallei and B. pseudomallei are closely related genetically; B. mallei evolved from an ancestral strain of B. pseudomallei by genome reduction and adaptation to an obligate intracellular lifestyle. Although these two bacteria cause different diseases, they share multiple virulence factors, including bacterial secretion systems, which represent key components of bacterial pathogenicity. Despite recent progress, the secretion system proteins for B. mallei and B. pseudomallei, their pathogenic mechanisms of action, and host factors are not well characterized. We previously developed a manually curated database, DBSecSys, of bacterial secretion system proteins for B. mallei. Here, we report an expansion of the database with corresponding information about B. pseudomallei. DBSecSys 2.0 contains comprehensive literature-based and computationally derived information about B. mallei ATCC 23344 and literature-based and computationally derived information about B. pseudomallei K96243. The database contains updated information for 163 B. mallei proteins from the previous database and 61 additional B. mallei proteins, and new information for 281 B. pseudomallei proteins associated with 5 secretion systems, their 1,633 human- and murine-interacting targets, and 2,400 host-B. mallei interactions and 2,286 host-B. pseudomallei interactions. The database also includes information about 13 pathogenic mechanisms of action for B. mallei and B. pseudomallei secretion system proteins inferred from the available literature or computationally. Additionally, DBSecSys 2.0 provides details about 82 virulence attenuation experiments for 52 B. mallei secretion system proteins and 98 virulence attenuation experiments for 61 B. pseudomallei secretion system proteins. We updated the Web interface and data access layer to speed-up users' search of detailed information for orthologous proteins related to secretion systems of the two pathogens. The updates of DBSecSys 2.0 provide unique capabilities to access comprehensive information about secretion systems of B. mallei and B. pseudomallei. They enable studies and comparisons of corresponding proteins of these two closely related pathogens and their host-interacting partners. The database is available at http://dbsecsys.bhsai.org .

DPP IV inhibitor treatment attenuates bone loss and improves mechanical bone strength in male diabetic rats.

PubMed

Glorie, Lorenzo; Behets, Geert J; Baerts, Lesley; De Meester, Ingrid; D'Haese, Patrick C; Verhulst, Anja

2014-09-01

Dipeptidyl peptidase IV (DPP IV) modulates protein activity by removing dipeptides. DPP IV inhibitors are currently used to improve glucose tolerance in type 2 diabetes patients. DPP IV substrates not only increase insulin secretion but also affect bone metabolism. In this study, the effect of DPP IV inhibitor sitagliptin on bone was evaluated in normal and streptozotocin-induced diabetic rats. This study included 64 male Wistar rats divided into four groups (n = 16): two diabetic and two control groups. One diabetic and one control group received sitagliptin through drinking water. Tibiae were scanned every 3 wk using an in vivo μCT scanner. After 6 and 12 wk, rats were euthanized for histomorphometric analysis of bone parameters. The mechanical resistance of femora to fracture was assessed using a three-point bending test, and serum levels of bone metabolic markers were measured. Efficient DPP IV inhibition was achieved in sitagliptin-treated groups. Trabecular bone loss, the decrease in trabecular number, and the increase in trabecular spacing was attenuated through sitagliptin treatment in diabetic rats, as shown by in vivo μCT. Bone histomorphometry was in line with these results. μCT analysis furthermore showed that sitagliptin prevented cortical bone growth stagnation in diabetic rats, resulting in stronger femora during three-point bending. Finally, the serum levels of the resorption marker CTX-I were significantly lower in sitagliptin-treated diabetic animals compared with untreated diabetic animals. In conclusion, sitagliptin treatment attenuates bone loss and increases bone strength in diabetic rats probably through the reduction of bone resorption and independent of glycemic management. Copyright © 2014 the American Physiological Society.

ARGOT: A System Overview,

DTIC Science & Technology

1982-04-01

the secret . In each, we shall consider * the plausible interpretations of the utterance "Do you know the secret ?" Setting 1: If S knows the secret and...believes that H doesn’t know the secret , then "Do you know the secret ?" is probably an offer to tell H the secret . Setting 2: If S doesn’t know the ... secret and believes that H does know the secret then "Do you know the

The use of gonadotrophin-releasing hormone antagonists in polycystic ovarian disease.

PubMed

Lubin, V; Charbonnel, B; Bouchard, P

1998-12-01

Polycystic ovarian disease (PCOD) is characterized by anovulation, eventually high luteinizing hormone (LH) levels, with increased LH pulse frequency, and hyperandrogenism. As the aetiology of the disease is still unknown, gonadotrophin-releasing hormone (GnRH) antagonists, competitive inhibitors of GnRH for its receptor, are interesting tools in order to study and treat the role of increased LH levels and pulse frequency in this disease. Their administration provokes a rapid decrease in bioactive and immunoactive LH followed by a slower decrease in follicle-stimulating hormone (FSH). In patients with PCOD, the suppression of gonadotrophin secretion eradicates the symptoms of the disease as long as the treatment lasts. Several authors have suggested that increased plasma LH levels have deleterious effects on the fertility of women with PCOD. Indeed, fewer spontaneous pregnancies with more miscarriages are observed when plasma LH levels are high. Assisted reproduction techniques such as in vitro fertilization (IVF) have provided other clues to the role of the LH secretory pattern in women with PCOD. The number of oocytes retrieved, the fertilization rate and the cleavage rate are lower in PCOD patients undergoing IVF and this is inversely correlated with FSH:LH ratio. These abnormalities are corrected when endogenous secretion of LH is suppressed. On the other hand, implantation and pregnancy rates after IVF are similar to those observed in control women. New GnRH antagonists are devoid of side effects and suppress LH secretion within a few hours without a flare-up effect. This action lasts for 10-100 hours. When GnRH antagonists are associated with i.v. pulsatile GnRH, this combination both suppresses the effect of endogenous GnRH and because of the competition for GnRH receptors restores a normal frequency of LH secretion. We have studied two women with PCOD, administering first 10 mg s.c. every 72 hours for 7 days of the GnRH antagonist Nal-Glu, then adding on top i.v. pulsatile GnRH: 10 micrograms/pulse every 90 minutes for 15 days. We thus succeeded in normalizing LH secretion pattern and observed a significant decline in testosterone levels. We failed to induce appropriate ovarian response and ovulation. In conclusion, the combination of GnRH antagonist and GnRH pulsatile treatment can re-establish normal LH secretory pattern in patients with PCOD. The failure to induce ovulation with this regimen suggests the existence of an inherent ovarian defect in women with PCOD.

The New Kid on the Block: A Specialized Secretion System during Bacterial Sporulation.

PubMed

Morlot, Cécile; Rodrigues, Christopher D A

2018-02-02

The transport of proteins across the bacterial cell envelope is mediated by protein complexes called specialized secretion systems. These nanomachines exist in both Gram-positive and Gram-negative bacteria and have been categorized into different types based on their structural components and function. Interestingly, multiple studies suggest the existence of a protein complex in endospore-forming bacteria that appears to be a new type of specialized secretion system. This protein complex is called the SpoIIIA-SpoIIQ complex and is an exception to the categorical norm since it appears to be a hybrid composed of different parts from well-defined specialized secretion systems. Here we summarize and discuss the current understanding of this complex and its potential role as a specialized secretion system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Diversity of secretion systems associated with virulence characteristics of the classical bordetellae.

PubMed

Park, Jihye; Zhang, Ying; Chen, Chun; Dudley, Edward G; Harvill, Eric T

2015-12-01

Secretion systems are key virulence factors, modulating interactions between pathogens and the host's immune response. Six potential secretion systems (types 1-6; T1SS-T6SS) have been discussed in classical bordetellae, respiratory commensals/pathogens of mammals. The prototypical Bordetella bronchiseptica strain RB50 genome seems to contain all six systems, whilst two human-restricted subspecies, Bordetella parapertussis and Bordetella pertussis, have lost different subsets of these. This implicates secretion systems in the divergent evolutionary histories that have led to their success in different niches. Based on our previous work demonstrating that changes in secretion systems are associated with virulence characteristics, we hypothesized there would be substantial divergence of the loci encoding each amongst sequenced strains. Here, we describe extensive differences in secretion system loci; 10 of the 11 sequenced strains had lost subsets of genes or one entire secretion system locus. These loci contained genes homologous to those present in the respective loci in distantly related organisms, as well as genes unique to bordetellae, suggesting novel and/or auxiliary functions. The high degree of conservation of the T3SS locus, a complex machine with interdependent parts that must be conserved, stands in dramatic contrast to repeated loss of T5aSS 'autotransporters', which function as an autonomous unit. This comparative analysis provided insights into critical aspects of each pathogen's adaptation to its different niche, and the relative contributions of recombination, mutation and horizontal gene transfer. In addition, the relative conservation of various secretion systems is an important consideration in the ongoing search for more highly conserved protective antigens for the next generation of pertussis vaccines.

A nonpungent component of steamed ginger--[10]-shogaol--increases adrenaline secretion via the activation of TRPV1.

PubMed

Iwasaki, Yusaku; Morita, Akihito; Iwasawa, Takahito; Kobata, Kenji; Sekiwa, Youko; Morimitsu, Yasujiro; Kubota, Kikue; Watanabe, Tatsuo

2006-01-01

We investigated the components of ginger that are involved in increasing body temperature. Gingerols ([6,8,10]-gingerols) and shogaols ([6,8,10]-shogaols) having different alkyl carbon chain lengths were targeted. All the gingerols and shogaols increased intracellular calcium concentration in rat transient receptor potential vanilloid subtype 1 (TRPV1)-expressing HEK293 cells via TRPV1. In this regard, the shogaols were more potent than the gingerols. Aversive responses were induced by [6]-, [10]-gingerol, and [6]-shogaol (5 mmol/l) in rats when these compounds were applied to the eye; however, no response was observed in response to [10]-shogaol (5 and 10 mmol/l). [10]-Shogaol induced nociceptive responses via TRPV1 in rats following its subcutaneous injection into the hindpaw; the pungent compound capsaicin (CAP) and [6]-shogaol were observed to have similar effects. Moreover, adrenal catecholamine secretion, which influences energy consumption, was promoted in rats in response to [6]- and [10]-gingerols and [6]- and [10]-shogaols (1.6 micromol/kg, i.v.). [10]-Shogaol-induced adrenaline secretion was inhibited by administration of capsazepine, a TRPV1 antagonist. In conclusion, gingerols and shogaols activated TRPV1 and increased adrenaline secretion. Interestingly, [10]-shogaol is the only nonpungent compound among the gingerols and shogaols, suggesting its usefulness as a functional ingredient in food.

Salmonella-secreted Virulence Factors

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

Heffron, Fred; Niemann, George; Yoon, Hyunjin

In this short review we discuss secreted virulence factors of Salmonella, which directly affect Salmonella interaction with its host. Salmonella secretes protein to subvert host defenses but also, as discussed, to reduce virulence thereby permitting the bacteria to persist longer and more successfully disperse. The type III secretion system (TTSS) is the best known and well studied of the mechanisms that enable secretion from the bacterial cytoplasm to the host cell cytoplasm. Other secretion systems include outer membrane vesicles, which are present in all Gram-negative bacteria examined to date, two-partner secretion, and type VI secretion will also be addressed. Excellentmore » reviews of Salmonella secreted effectors have focused on themes such as actin rearrangements, vesicular trafficking, ubiquitination, and the activities of the virulence factors themselves. This short review is based on S. Typhimurium infection of mice because it is a model of typhoid like disease in humans. We have organized effectors in terms of events that happen during the infection cycle and how secreted effectors may be involved.« less

Proteinaceous determinants of surface colonization in bacteria: bacterial adhesion and biofilm formation from a protein secretion perspective

PubMed Central

Chagnot, Caroline; Zorgani, Mohamed A.; Astruc, Thierry; Desvaux, Mickaël

2013-01-01

Bacterial colonization of biotic or abiotic surfaces results from two quite distinct physiological processes, namely bacterial adhesion and biofilm formation. Broadly speaking, a biofilm is defined as the sessile development of microbial cells. Biofilm formation arises following bacterial adhesion but not all single bacterial cells adhering reversibly or irreversibly engage inexorably into a sessile mode of growth. Among molecular determinants promoting bacterial colonization, surface proteins are the most functionally diverse active components. To be present on the bacterial cell surface, though, a protein must be secreted in the first place. Considering the close association of secreted proteins with their cognate secretion systems, the secretome (which refers both to the secretion systems and their protein substrates) is a key concept to apprehend the protein secretion and related physiological functions. The protein secretion systems are here considered in light of the differences in the cell-envelope architecture between diderm-LPS (archetypal Gram-negative), monoderm (archetypal Gram-positive) and diderm-mycolate (archetypal acid-fast) bacteria. Besides, their cognate secreted proteins engaged in the bacterial colonization process are regarded from single protein to supramolecular protein structure as well as the non-classical protein secretion. This state-of-the-art on the complement of the secretome (the secretion systems and their cognate effectors) involved in the surface colonization process in diderm-LPS and monoderm bacteria paves the way for future research directions in the field. PMID:24133488

Reactions of green lizards (Lacerta viridis) to major repellent compounds secreted by Graphosoma lineatum (Heteroptera: Pentatomidae).

PubMed

Gregorovičová, Martina; Černíková, Alena

2015-06-01

The chemical defence of Heteroptera is primarily based on repellent secretions which signal the potential toxicity of the bug to its predators. We tested the aversive reactions of green lizards (Lacerta viridis) towards the major compounds of the defensive secretion of Graphosoma lineatum, specifically: (i) a mixture of three aldehydes: (E)-hex-2-enal, (E)-oct-2-enal, (E)-dec-2-enal; (ii) a mixture of these three aldehydes and tridecane; (iii) oxoaldehyde: (E)-4-oxohex-2-enal; (iv) secretion extracted from metathoracic scent glands of G. lineatum adults and (v) hexane as a non-polar solvent. All chemicals were presented on a palatable food (Tenebrio molitor larvae). The aversive reactions of the green lizards towards the mealworms were evaluated by observing the approach latencies, attack latencies and approach-attack intervals. The green lizards exhibited a strong aversive reaction to the mixture of three aldehydes. Tridecane reduced the aversive reaction to the aldehyde mixture. Oxoaldehyde caused the weakest, but still significant, aversive reaction. The secretion from whole metathoracic scent glands also clearly had an aversive effect on the green lizards. Moreover, when a living specimen of G. lineatum or Pyrrhocoris apterus (another aposematic red-and-black prey) was presented to the green lizards before the trials with the aldehyde mixture, the aversive effect of the mixture was enhanced. In conclusion, the mixture of three aldehydes had the strong aversive effect and could signal the potential toxicity of G. lineatum to the green lizards. Copyright © 2015 Elsevier GmbH. All rights reserved.

Master manipulators: an update on Legionella pneumophila Icm/Dot translocated substrates and their host targets

PubMed Central

Isaac, Dervla T; Isberg, Ralph

2014-01-01

Macrophages are the front line of immune defense against invading microbes. Microbes, however, have evolved numerous and diverse mechanisms to thwart these host immune defenses and thrive intracellularly. Legionella pneumophila, a Gram-negative pathogen of amoebal and mammalian phagocytes, is one such microbe. In humans, it causes a potentially fatal pneumonia referred to as Legionnaires' disease. Armed with the Icm/Dot type IV secretion system, which is required for virulence, and approximately 300 translocated proteins, Legionella is able to enter host cells, direct the biogenesis of its own vacuolar compartment, and establish a replicative niche, where it grows to high levels before lysing the host cell. Efforts to understand the pathogenesis of this bacterium have focused on characterizing the molecular activities of its many effectors. In this article, we highlight recent strides that have been made in understanding how Legionella effectors mediate host-pathogen interactions. PMID:24762308

Genome Dynamics in Legionella: The Basis of Versatility and Adaptation to Intracellular Replication

PubMed Central

Gomez-Valero, Laura; Buchrieser, Carmen

2013-01-01

Legionella pneumophila is a bacterial pathogen present in aquatic environments that can cause a severe pneumonia called Legionnaires’ disease. Soon after its recognition, it was shown that Legionella replicates inside amoeba, suggesting that bacteria replicating in environmental protozoa are able to exploit conserved signaling pathways in human phagocytic cells. Comparative, evolutionary, and functional genomics suggests that the Legionella–amoeba interaction has shaped this pathogen more than previously thought. A complex evolutionary scenario involving mobile genetic elements, type IV secretion systems, and horizontal gene transfer among Legionella, amoeba, and other organisms seems to take place. This long-lasting coevolution led to the development of very sophisticated virulence strategies and a high level of temporal and spatial fine-tuning of bacteria host–cell interactions. We will discuss current knowledge of the evolution of virulence of Legionella from a genomics perspective and propose our vision of the emergence of this human pathogen from the environment. PMID:23732852

Comparative Screening of Digestion Tract Toxic Genes in Proteus mirabilis

PubMed Central

Shi, Xiaolu; Lin, Yiman; Qiu, Yaqun; Li, Yinghui; Jiang, Min; Chen, Qiongcheng; Jiang, Yixiang; Yuan, Jianhui; Cao, Hong; Hu, Qinghua; Huang, Shenghe

2016-01-01

Proteus mirabilis is a common urinary tract pathogen, and may induce various inflammation symptoms. Its notorious ability to resist multiple antibiotics and to form urinary tract stones makes its treatment a long and painful process, which is further challenged by the frequent horizontal gene transferring events in P. mirabilis genomes. Three strains of P. mirabilis C02011/C04010/C04013 were isolated from a local outbreak of a food poisoning event in Shenzhen, China. Our hypothesis is that new genes may have been acquired horizontally to exert the digestion tract infection and toxicity. The functional characterization of these three genomes shows that each of them independently acquired dozens of virulent genes horizontally from the other microbial genomes. The representative strain C02011 induces the symptoms of both vomit and diarrhea, and has recently acquired a complete type IV secretion system and digestion tract toxic genes from the other bacteria. PMID:27010388

Comparative Screening of Digestion Tract Toxic Genes in Proteus mirabilis.

PubMed

Shi, Xiaolu; Lin, Yiman; Qiu, Yaqun; Li, Yinghui; Jiang, Min; Chen, Qiongcheng; Jiang, Yixiang; Yuan, Jianhui; Cao, Hong; Hu, Qinghua; Huang, Shenghe

2016-01-01

Proteus mirabilis is a common urinary tract pathogen, and may induce various inflammation symptoms. Its notorious ability to resist multiple antibiotics and to form urinary tract stones makes its treatment a long and painful process, which is further challenged by the frequent horizontal gene transferring events in P. mirabilis genomes. Three strains of P. mirabilis C02011/C04010/C04013 were isolated from a local outbreak of a food poisoning event in Shenzhen, China. Our hypothesis is that new genes may have been acquired horizontally to exert the digestion tract infection and toxicity. The functional characterization of these three genomes shows that each of them independently acquired dozens of virulent genes horizontally from the other microbial genomes. The representative strain C02011 induces the symptoms of both vomit and diarrhea, and has recently acquired a complete type IV secretion system and digestion tract toxic genes from the other bacteria.

Gastric Carcinogenesis and Underlying Molecular Mechanisms: Helicobacter pylori and Novel Targeted Therapy

PubMed Central

Nishizawa, Toshihiro

2015-01-01

The oxygen-derived free radicals that are released from activated neutrophils are one of the cytotoxic factors of Helicobacter pylori-induced gastric mucosal injury. Increased cytidine deaminase activity in H. pylori-infected gastric tissues promotes the accumulation of various mutations and might promote gastric carcinogenesis. Cytotoxin-associated gene A (CagA) is delivered into gastric epithelial cells via bacterial type IV secretion system, and it causes inflammation and activation of oncogenic pathways. H. pylori infection induces epigenetic transformations, such as aberrant promoter methylation in tumor-suppressor genes. Aberrant expression of microRNAs is also reportedly linked to gastric tumorogenesis. Moreover, recent advances in molecular targeting therapies provided a new interesting weapon to treat advanced gastric cancer through anti-human epidermal growth factor receptor 2 (HER-2) therapies. This updated review article highlights possible mechanisms of gastric carcinogenesis including H. pylori-associated factors. PMID:25945346

Comparative genomics of Paracoccus sp. SM22M-07 isolated from coral mucus: insights into bacteria-host interactions.

PubMed

Carlos, Camila; Pereira, Letícia Bianca; Ottoboni, Laura Maria Mariscal

2017-06-01

One of the main goals of coral microbiology is to understand the ways in which coral-bacteria associations are established and maintained. This work describes the sequencing of the genome of Paracoccus sp. SM22M-07 isolated from the mucus of the endemic Brazilian coral species Mussismilia hispida. Comparative analysis was used to identify unique genomic features of SM22M-07 that might be involved in its adaptation to the marine ecosystem and the nutrient-rich environment provided by coral mucus, as well as in the establishment and strengthening of the interaction with the host. These features included genes related to the type IV protein secretion system, erythritol catabolism, and succinoglycan biosynthesis. We experimentally confirmed the production of succinoglycan by Paracoccus sp. SM22M-07 and we hypothesize that it may be involved in the association of the bacterium with coral surfaces.

Genome dynamics in Legionella: the basis of versatility and adaptation to intracellular replication.

PubMed

Gomez-Valero, Laura; Buchrieser, Carmen

2013-06-01

Legionella pneumophila is a bacterial pathogen present in aquatic environments that can cause a severe pneumonia called Legionnaires' disease. Soon after its recognition, it was shown that Legionella replicates inside amoeba, suggesting that bacteria replicating in environmental protozoa are able to exploit conserved signaling pathways in human phagocytic cells. Comparative, evolutionary, and functional genomics suggests that the Legionella-amoeba interaction has shaped this pathogen more than previously thought. A complex evolutionary scenario involving mobile genetic elements, type IV secretion systems, and horizontal gene transfer among Legionella, amoeba, and other organisms seems to take place. This long-lasting coevolution led to the development of very sophisticated virulence strategies and a high level of temporal and spatial fine-tuning of bacteria host-cell interactions. We will discuss current knowledge of the evolution of virulence of Legionella from a genomics perspective and propose our vision of the emergence of this human pathogen from the environment.

Draft genome sequence of Paraburkholderia tropica Ppe8 strain, a sugarcane endophytic diazotrophic bacterium.

PubMed

Silva, Paula Renata Alves da; Simões-Araújo, Jean Luiz; Vidal, Márcia Soares; Cruz, Leonardo Magalhães; Souza, Emanuel Maltempi de; Baldani, José Ivo

Paraburkholderia tropica (syn Burkholderia tropica) are nitrogen-fixing bacteria commonly found in sugarcane. The Paraburkholderia tropica strain Ppe8 is part of the sugarcane inoculant consortium that has a beneficial effect on yield. Here, we report a draft genome sequence of this strain elucidating the mechanisms involved in its interaction mainly with Poaceae. A genome size of approximately 8.75Mb containing 7844 protein coding genes distributed in 526 subsystems was de novo assembled with ABySS and annotated by RAST. Genes related to the nitrogen fixation process, the secretion systems (I, II, III, IV, and VI), and related to a variety of metabolic traits, such as metabolism of carbohydrates, amino acids, vitamins, and proteins, were detected, suggesting a broad metabolic capacity and possible adaptation to plant association. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Gliding Motility and Por Secretion System Genes Are Widespread among Members of the Phylum Bacteroidetes

PubMed Central

Zhu, Yongtao

2013-01-01

The phylum Bacteroidetes is large and diverse, with rapid gliding motility and the ability to digest macromolecules associated with many genera and species. Recently, a novel protein secretion system, the Por secretion system (PorSS), was identified in two members of the phylum, the gliding bacterium Flavobacterium johnsoniae and the nonmotile oral pathogen Porphyromonas gingivalis. The components of the PorSS are not similar in sequence to those of other well-studied bacterial secretion systems. The F. johnsoniae PorSS genes are a subset of the gliding motility genes, suggesting a role for the secretion system in motility. The F. johnsoniae PorSS is needed for assembly of the gliding motility apparatus and for secretion of a chitinase, and the P. gingivalis PorSS is involved in secretion of gingipain protease virulence factors. Comparative analysis of 37 genomes of members of the phylum Bacteroidetes revealed the widespread occurrence of gliding motility genes and PorSS genes. Genes associated with other bacterial protein secretion systems were less common. The results suggest that gliding motility is more common than previously reported. Microscopic observations confirmed that organisms previously described as nonmotile, including Croceibacter atlanticus, “Gramella forsetii,” Paludibacter propionicigenes, Riemerella anatipestifer, and Robiginitalea biformata, exhibit gliding motility. Three genes (gldA, gldF, and gldG) that encode an apparent ATP-binding cassette transporter required for F. johnsoniae gliding were absent from two related gliding bacteria, suggesting that the transporter may not be central to gliding motility. PMID:23123910

Engineering Escherichia coli into a protein delivery system for mammalian cells.

PubMed

Reeves, Analise Z; Spears, William E; Du, Juan; Tan, Kah Yong; Wagers, Amy J; Lesser, Cammie F

2015-05-15

Many Gram-negative pathogens encode type 3 secretion systems, sophisticated nanomachines that deliver proteins directly into the cytoplasm of mammalian cells. These systems present attractive opportunities for therapeutic protein delivery applications; however, their utility has been limited by their inherent pathogenicity. Here, we report the reengineering of a laboratory strain of Escherichia coli with a tunable type 3 secretion system that can efficiently deliver heterologous proteins into mammalian cells, thereby circumventing the need for virulence attenuation. We first introduced a 31 kB region of Shigella flexneri DNA that encodes all of the information needed to form the secretion nanomachine onto a plasmid that can be directly propagated within E. coli or integrated into the E. coli chromosome. To provide flexible control over type 3 secretion and protein delivery, we generated plasmids expressing master regulators of the type 3 system from either constitutive or inducible promoters. We then constructed a Gateway-compatible plasmid library of type 3 secretion sequences to enable rapid screening and identification of sequences that do not perturb function when fused to heterologous protein substrates and optimized their delivery into mammalian cells. Combining these elements, we found that coordinated expression of the type 3 secretion system and modified target protein substrates produces a nonpathogenic strain that expresses, secretes, and delivers heterologous proteins into mammalian cells. This reengineered system thus provides a highly flexible protein delivery platform with potential for future therapeutic applications.

Recombinant porcine epidermal growth factor-secreting Lactococcus lactis promotes the growth performance of early-weaned piglets

PubMed Central

2014-01-01

Background Epidermal growth factor (EGF) is an important growth factor in regulation of cell proliferation, differentiation, survival and apoptosis. Studies showed that food-grade Lactococcus lactis (L. lactis) and NICE expression system have superior performance in exogenous protein expression. This study aimed to construct and express porcine EGF (pEGF), and use L. lactis as vehicle for producing and delivering pEGF. Furthermore, investigating biological activity of pEGF and exploring applications feasibility of combination effects of L. lactis and pEGF on early weaned piglets’ production. Results A recombinant Lactococcus lactis which produced and secreted pEGF at 1000 ng/ml in culture supernatant was generated. Secreted pEGF was a fully biologically active protein, as demonstrated by its capacity to stimulate L929 mouse fibroblast cell line proliferation in vitro. For in vivo study, forty piglets were randomly allocated to control, antibiotic control, empty vector-expressing L. lactis (LL-EV) and pEGF-secreting L. lactis (LL-pEGF). After 14 d of rearing, final body weight and average daily gain in LL-pEGF were greater (P < 0.05, 8.95 vs. 8.37 kg, 206.1 vs. 157.7 g/day, respectively) than those in control, but no significant differences between LL-pEGF, LL-EV and antibiotic control. Overall period average daily feed intake was higher in LL-pEGF, LL-EV and antibiotic control than in control (P < 0.05, 252.9, 255.6, 250.0, 207.3 g/day, respectively). No significant difference was observed on ADFI/ADG. LL-pEGF increased villous height in the duodenum, jejunum and ileum than in control and LL-EV (P < 0.05). Sucrase in the 3 intestinal segments, aminopeptidase A in the duodenum and Jejunum, aminopeptidase N and dipeptidase IV in the duodenum in LL-pEGF were higher than those in control (P < 0.05). Furthermore, Escherichia coli and Enterococcus counts decreased in the ileum and Lactobacillus increased in the ileum and cecum digesta in LL-pEGF compare with the control (P < 0.05). Lactobacillus increased in the cecum in LL-EV compared with control and antibiotic control (P < 0.05). Conclusion We have generated a recombinant Lactococcus lactis which produced and secreted fully biologically active porcine EGF. Oral administration of pEGF-secreting L. lactis had beneficial effects on intestinal health and performance of early-weaned piglets. PMID:25142032

The action of bombesin on the kidney of the anaesthetized dog.

PubMed

Erspamer, V; Melchiorri, P; Sopranzi, N

1973-07-01

1. In the anaesthetized dog bombesin had a potent antidiuretic effect, and sometimes arrested urine flow completely. Threshold doses, by i.v. infusion, were of the order of 0.5-1 (ng/kg)/minute. Antidiuresis was the result of a reduction in glomerular filtration rate provoked by a fall in intraglomerular hydrostatic pressure. This, in its turn, was due to afferent vasoconstriction.2. The spasmogenic effect of bombesin on the smooth muscle of the afferent arterioles was directly demonstrated by the radioactive microspheres technique and indirectly by the (85)Kr washout method and by [(3)H]-p-aminohippurate clearance. The vascular compartment most sensitive to bombesin was that of the outer cortical zone, especially in its external half.3. Filtration fraction decreased under the influence of bombesin, indicating that the effect of the polypeptide on postglomerular arterioles was, if present, only of minor importance.4. At high infusion rates (above 6 (ng/kg)/min), bombesin produced a decrease in [(3)H]-p-aminohippurate extraction. The effect of the polypeptide on fractional distal delivery of sodium varied with the dose: at moderate infusion rates it decreased, at high infusion rates it increased. The total glucose appearing in urine following a glucose load was sharply reduced by bombesin. However, the glomerular filtration rate/maximum tubular glucose transport ratio did not show any appreciable change.5. Afferent vasoconstriction produced by bombesin was accompanied by an intense activation of the renin-angiotensin system, as shown by a conspicuous increase in renin secretion, followed by increases in renin activity and angiotensin II concentration in arterial blood. When bombesin was infused into one renal artery only the infused kidney showed afferent vasoconstriction and increased renin secretion. The time-course of renin secretion produced by bombesin depended upon the rate of infusion of the polypeptide. At low rates an increased renin secretion was observed throughout the infusion period, at high rates two peaks of renin secretion could be seen, one at the beginning of the infusion, the other soon after the infusion had finished.6. The mechanism of action of bombesin is discussed and the interest of the polypeptide as a possible hormonal regulator of the circulation and function of the kidney is pointed out.

Inflammatory signaling pathways induced by Helicobacter pylori in primary human gastric epithelial cells.

PubMed

Tran, Cong Tri; Garcia, Magali; Garnier, Martine; Burucoa, Christophe; Bodet, Charles

2017-02-01

Inflammatory signaling pathways induced by Helicobacter pylori remain unclear, having been studied mostly on cell-line models derived from gastric adenocarcinoma with potentially altered signaling pathways and nonfunctional receptors. Here, H. pylori-induced signaling pathways were investigated in primary human gastric epithelial cells. Inflammatory response was analyzed on chemokine mRNA expression and production after infection of gastric epithelial cells by H. pylori strains, B128 and B128Δ cagM, a cag type IV secretion system defective strain. Signaling pathway involvement was investigated using inhibitors of epidermal growth factor receptor (EGFR), MAPK, JAK and blocking Abs against TLR2 and TLR4. Inhibitors of EGFR, MAPK and JAK significantly reduced the chemokine mRNA expression and production induced by both H. pylori strains at 3 h and 24 h post-infection. JNK inhibitor reduced chemokine production at 24 h post-infection. Blocking Abs against TLR2 but not TLR4 showed significant reduction of chemokine secretion. Using primary culture of human gastric epithelial cells, our data suggest that H. pylori can be recognized by TLR2, leading to chemokine induction, and that EGFR, MAPK and the JAK/STAT signaling pathways play a key role in the H. pylori-induced CXCL1, CXCL5 and CXCL8 response in a cag pathogenicity island-independent manner.

Multipronged regulatory functions of a novel endonuclease (TieA) from Helicobacter pylori.

PubMed

Devi, Savita; Ansari, Suhail A; Tenguria, Shivendra; Kumar, Naveen; Ahmed, Niyaz

2016-11-02

Helicobacter pylori portrays a classical paradigm of persistent bacterial infections. A well balanced homeostasis of bacterial effector functions and host responses is purported to be the key in achieving long term colonization in specific hosts. H. pylori nucleases have been shown to assist in natural transformation, but their role in virulence and colonization remains elusive. Therefore, it is imperative to understand the involvement of these nucleases in the pathogenesis of H. pylori Here, we report the multifaceted role of a TNFR-1 interacting endonuclease A (TieA) from H. pylori. tieA expression is differentially regulated in response to environmental stress and post adherence to gastric epithelial cells. Studies with isogenic knockouts of tieA revealed it to be a secretory protein which translocates into the host gastric epithelial cells independent of a type IV secretion system, gets phosphorylated by DNA-PK kinase and auto-phosphorylates as serine kinase. Furthermore, TieA binds to and cleaves DNA in a non-specific manner and promotes Fas mediated apoptosis in AGS cells. Additionally, TieA induced pro-inflammatory cytokine secretion via activation of transcription factor AP-1 and signaled through MAP kinase pathway. Collectively, TieA with its multipronged and moonlighting functions could facilitate H. pylori in maintaining a balance of bacterial adaptation, and elimination by the host responses. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Escherichia coli type III secretion system 2: a new kind of T3SS?

PubMed

Zhou, Mingxu; Guo, Zhiyan; Duan, Qiangde; Hardwidge, Philip R; Zhu, Guoqiang

2014-03-19

Type III secretion systems (T3SSs) are employed by Gram-negative bacteria to deliver effector proteins into the cytoplasm of infected host cells. Enteropathogenic Escherichia coli use a T3SS to deliver effector proteins that result in the creation of the attaching and effacing lesions. The genome sequence of the Escherichia coli pathotype O157:H7 revealed the existence of a gene cluster encoding components of a second type III secretion system, the E. coli type III secretion system 2 (ETT2). Researchers have revealed that, although ETT2 may not be a functional secretion system in most (or all) strains, it still plays an important role in bacterial virulence. This article summarizes current knowledge regarding the E. coli ETT2, including its genetic characteristics, prevalence, function, association with virulence, and prospects for future work.

Granulopoietic Growth Factor Secretion in Ovarian Carcinoma as a Mechanism for the Emergence of Immune Suppressive Myeloid Subsets

DTIC Science & Technology

2014-08-01

levels will be determined and tracked biweekly during the course of tumor growth. Age/ gender -matched non-tumor-bearing mice will serve as controls for...parameter flow cytometry, we compared 21 ovarian cancer patients reflecting stages II - IV to 22 gender - race- and age-matched controls. All patient...Sitkovsky, M. A2A adenosine receptors protect tumors from anti- tumor T cells. (*equal authorship ) Proc. Natl. Acad. Sci. USA 103: 13132-13137, 2006

Proteomic Studies of Cholangiocarcinoma and Hepatocellular Carcinoma Cell Secretomes

PubMed Central

Srisomsap, Chantragan; Sawangareetrakul, Phannee; Subhasitanont, Pantipa; Chokchaichamnankit, Daranee; Chiablaem, Khajeelak; Bhudhisawasdi, Vaharabhongsa; Wongkham, Sopit; Svasti, Jisnuson

2010-01-01

Cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC) occur with relatively high incidence in Thailand. The secretome, proteins secreted from cancer cells, are potentially useful as biomarkers of the diseases. Proteomic analysis was performed on the secreted proteins of cholangiocarcinoma (HuCCA-1) and hepatocellular carcinoma (HCC-S102, HepG2, SK-Hep-1, and Alexander) cell lines. The secretomes of the five cancer cell lines were analyzed by SDS-PAGE combined with LC/MS/MS. Sixty-eight proteins were found to be expressed only in HuCCA-1. Examples include neutrophil gelatinase-associated lipocalin (lipocalin 2), laminin 5 beta 3, cathepsin D precursor, desmoplakin, annexin IV variant, and annexin A5. Immunoblotting was used to confirm the presence of lipocalin 2 in conditioned media and cell lysate of 5 cell lines. The results showed that lipocalin 2 was a secreted protein which is expressed only in the conditioned media of the cholangiocarcinoma cell line. Study of lipocalin 2 expression in different types of cancer and normal tissues from cholangiocarcinoma patients showed that lipocalin 2 was expressed only in the cancer tissues. We suggest that lipocalin 2 may be a potential biomarker for cholangiocarcinoma. PMID:20069059

Suppression of glioblastoma angiogenicity and tumorigenicity by inhibition of endogenous expression of vascular endothelial growth factor.

PubMed Central

Cheng, S Y; Huang, H J; Nagane, M; Ji, X D; Wang, D; Shih, C C; Arap, W; Huang, C M; Cavenee, W K

1996-01-01

The development of new capillary networks from the normal microvasculature of the host appears to be required for growth of solid tumors. Tumor cells influence this process by producing both inhibitors and positive effectors of angiogenesis. Among the latter, the vascular endothelial growth factor (VEGF) has assumed prime candidacy as a major positive physiological effector. Here, we have directly tested this hypothesis in the brain tumor, glioblastoma multiforme, one of the most highly vascularized human cancers. We introduced an antisense VEGF expression construct into glioblastoma cells and found that (i) VEGF mRNA and protein levels were markedly reduced, (ii) the modified cells did not secrete sufficient factors so as to be chemoattractive for primary human microvascular endothelial cells, (iii) the modified cells were not able to sustain tumor growth in immunodeficient animals, and (iv) the density of in vivo blood vessel formation was reduced in direct relation to the reduction of VEGF secretion and tumor formation. Moreover, revertant cells that recovered the ability to secrete VEGF regained each of these tumorigenic properties. These results suggest that VEGF plays a major angiogenic role in glioblastoma. Images Fig. 1 Fig. 4 PMID:8710899

Increasing LH Pulsatility in Women With Hypothalamic Amenorrhoea Using Intravenous Infusion of Kisspeptin-54

PubMed Central

Jayasena, Channa N.; Abbara, Ali; Veldhuis, Johannes D.; Comninos, Alexander N.; Ratnasabapathy, Risheka; De Silva, Akila; Nijher, Gurjinder M. K.; Ganiyu-Dada, Zainab; Mehta, Amrish; Todd, Catriona; Ghatei, Mohammad A.; Bloom, Stephen R.

2014-01-01

Background: Hypothalamic amenorrhea (HA) is the one of the most common causes of period loss in women of reproductive age and is associated with deficient LH pulsatility. High-dose kisspeptin-54 acutely stimulates LH secretion in women with HA, but chronic administration causes desensitization. GnRH has paradoxical effects on reproductive activity; we therefore hypothesized that a dose-dependent therapeutic window exists within which kisspeptin treatment restores the GnRH/LH pulsatility in women with HA. Aim: The aim of the study was to determine whether constant iv infusion of kisspeptin-54 temporarily increases pulsatile LH secretion in women with HA. Methods: Five patients with HA each underwent six assessments of LH pulsatility. Single-blinded continuous iv infusion of vehicle or kisspeptin-54 (0.01, 0.03, 0.10, 0.30, or 1.00 nmol/kg/h) was administered. The LH pulses were detected using blinded deconvolution. Results: Kisspeptin increased LH pulsatility in all patients with HA, with peak responses observed at different doses in each patient. The mean peak number of pulses during infusion of kisspeptin-54 was 3-fold higher when compared with vehicle (number of LH pulses per 8 h: 1.6 ± 0.4, vehicle; 5.0 ± 0.5, kisspeptin-54, P < .01 vs vehicle). The mean peak LH pulse secretory mass during kisspeptin-54 was 6-fold higher when compared with vehicle (LH pulse secretory mass in international units per liter: 3.92 ± 2.31, vehicle; 23.44 ± 12.59, kisspeptin-54; P < .05 vs vehicle). Conclusions: Kisspeptin-54 infusion temporarily increases LH pulsatility in women with HA. Furthermore, we have determined the dose range within which kisspeptin-54 treatment increases basal and pulsatile LH secretion in women with HA. This work provides a basis for studying the potential of kisspeptin-based therapies to treat women with HA. PMID:24517142

Specific Accumulation of Tumor-Derived Adhesion Factor in Tumor Blood Vessels and in Capillary Tube-Like Structures of Cultured Vascular Endothelial Cells

NASA Astrophysics Data System (ADS)

Akaogi, Kotaro; Okabe, Yukie; Sato, Junji; Nagashima, Yoji; Yasumitsu, Hidetaro; Sugahara, Kazuyuki; Miyazaki, Kaoru

1996-08-01

Tumor-derived adhesion factor (TAF) was previously identified as a cell adhesion molecule secreted by human bladder carcinoma cell line EJ-1. To elucidate the physiological function of TAF, we examined its distribution in human normal and tumor tissues. Immunochemical staining with an anti-TAF monoclonal antibody showed that TAF was specifically accumulated in small blood vessels and capillaries within and adjacent to tumor nests, but not in those in normal tissues. Tumor blood vessel-specific staining of TAF was observed in various human cancers, such as esophagus, brain, lung, and stomach cancers. Double immunofluorescent staining showed apparent colocalization of TAF and type IV collagen in the vascular basement membrane. In vitro experiments demonstrated that TAF preferentially bound to type IV collagen among various extracellular matrix components tested. In cell culture experiments, TAF promoted adhesion of human umbilical vein endothelial cells to type IV collagen substrate and induced their morphological change. Furthermore, when the endothelial cells were induced to form capillary tube-like structures by type I collagen, TAF and type IV collagen were exclusively detected on the tubular structures. The capillary tube formation in vitro was prevented by heparin, which inhibited the binding of TAF to the endothelial cells. These results strongly suggest that TAF contributes to the organization of new capillary vessels in tumor tissues by modulating the interaction of endothelial cells with type IV collagen.

Authentication Without Secrets

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

Pierson, Lyndon G.; Robertson, Perry J.

This work examines a new approach to authentication, which is the most fundamental security primitive that underpins all cyber security protections. Current Internet authentication techniques require the protection of one or more secret keys along with the integrity protection of the algorithms/computations designed to prove possession of the secret without actually revealing it. Protecting a secret requires physical barriers or encryption with yet another secret key. The reason to strive for "Authentication without Secret Keys" is that protecting secrets (even small ones only kept in a small corner of a component or device) is much harder than protecting the integritymore » of information that is not secret. Promising methods are examined for authentication of components, data, programs, network transactions, and/or individuals. The successful development of authentication without secret keys will enable far more tractable system security engineering for high exposure, high consequence systems by eliminating the need for brittle protection mechanisms to protect secret keys (such as are now protected in smart cards, etc.). This paper is a re-release of SAND2009-7032 with new figures numerous edits.« less

NMDA inhibits oxotremorine-induced acid secretion via the NO-dependent cyclic GMP system in rat stomach.

PubMed

Tsai, L H; Lee, Y J

2001-12-31

The mechanism of N-methyl-D-aspartate (NMDA) inhibits oxotremorine-induced acid secretion was examined in rat stomach, in relation to the cyclic GMP system. NMDA (10(-7) M) did not affect the spontaneous acid secretion from the everted preparations of isolated rat stomach, but inhibited the acid secretion stimulated by oxotremorine, and this effect of NMDA was antagonized by 2-amino-5-phosphonovaleric acid (AP-5), (+/-)3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) or N(G)-nitro-L-arginine (L-NNA). NMDA also elevated the cyclic GMP content of mucosal slices from rat stomach, and this effect of NMDA was antagonized by L-NNA. These results indicate that NMDA receptors are present in the rat stomach and regulate the gastric acid secretion. The mechanism underlying the effect of NMDA inhibits oxotremorine-induced acid secretion may be mediated by the NO-dependent cyclic GMP system.

Twin-arginine signal peptide of Bacillus subtilis YwbN can direct Tat-dependent secretion of methyl parathion hydrolase.

PubMed

Liu, Ruihua; Zuo, Zhenqiang; Xu, Yingming; Song, Cunjiang; Jiang, Hong; Qiao, Chuanling; Xu, Ping; Zhou, Qixing; Yang, Chao

2014-04-02

The twin-arginine translocation (Tat) pathway exports folded proteins across the cytoplasmic membranes of bacteria and archaea. Two parallel Tat pathways (TatAdCd and TatAyCy systems) with distinct substrate specificities have previously been discovered in Bacillus subtilis. In this study, to secrete methyl parathion hydrolase (MPH) into the growth medium, the twin-arginine signal peptide of B. subtilis YwbN was used to target MPH to the Tat pathway of B. subtilis. Western blot analysis and MPH assays demonstrated that active MPH was secreted into the culture supernatant of wild-type cells. No MPH secretion occurred in a total-tat2 mutant, indicating that the observed export in wild-type cells was mediated exclusively by the Tat pathway. Export was fully blocked in a tatAyCy mutant. In contrast, the tatAdCd mutant was still capable of secreting MPH. These results indicated that the MPH secretion directed by the YwbN signal peptide was specifically mediated by the TatAyCy system. The N-terminal sequence of secreted MPH was determined as AAPQVR, demonstrating that the YwbN signal peptide had been processed correctly. This is the first report of functional secretion of a heterologous protein via the B. subtilis TatAyCy system. This study highlights the potential of the TatAyCy system to be used for secretion of other heterologous proteins in B. subtilis.

The type IX secretion system is required for virulence of the fish pathogen Flavobacterium columnare

USDA-ARS?s Scientific Manuscript database

Flavobacterium columnare, a member of the phylum Bacteroidetes, causes columnaris disease in wild and aquaculture-reared freshwater fish. The mechanisms responsible for columnaris disease are not known. Many members of the phylum Bacteroidetes use type IX secretion systems (T9SSs) to secrete enzymes...

21 CFR 866.5360 - Cohn fraction IV immuno-logical test system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Immunological Test Systems § 866.5360 Cohn fraction IV immuno-logical test system. (a) Identification. A Cohn fraction IV immunological... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cohn fraction IV immuno-logical test system. 866...

Quantum secret sharing with qudit graph states

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

Keet, Adrian; Fortescue, Ben; Sanders, Barry C.

We present a unified formalism for threshold quantum secret sharing using graph states of systems with prime dimension. We construct protocols for three varieties of secret sharing: with classical and quantum secrets shared between parties over both classical and quantum channels.

Type IV Effector Proteins Involved in the Medicago-Sinorhizobium Symbiosis.

PubMed

Nelson, Matthew S; Chun, Chan Lan; Sadowsky, Michael J

2017-01-01

In this study, we investigated genetic elements of the type IV secretion system (T4SS) found in Sinorhizobium spp. and the role they play in symbiosis. Sinorhizobium meliloti and S. medicae each contain a putative T4SS similar to that used by Agrobacterium tumefaciens during pathogenesis. The Cre reporter assay for translocation system was used to validate potential effector proteins. Both S. meliloti and S. medicae contained the effector protein TfeA, which was translocated into the host plant. Sequence analysis revealed the presence of a nod box involved in transcriptional activation of symbiosis-related genes, upstream of the transcriptional regulator (virG) in the Sinorhizobium T4SS. Replicate quantitative reverse transcription-polymerase chain reaction analyses indicated that luteolin, released by roots and seeds of Medicago truncatula, upregulated transcription of tfeA and virG. Mutations in the T4SS apparatus or tfeA alone resulted in reduced numbers of nodules formed on M. truncatula genotypes. In addition, S. meliloti KH46c, which contains a deletion in the T4SS, was less competitive for nodule formation when coinoculated with an equal number of cells of the wild-type strain. To our knowledge, TfeA is the first T4SS effector protein identified in Sinorhizobium spp. Our results indicate that Sinorhizobium i) uses a T4SS during initiation of symbiosis with Medicago spp., and ii) alters Medicago cells in planta during symbiosis. This study also offers additional bioinformatic evidence that several different rhizobial species may use the T4SS in symbiosis with other legumes.

Structure of a PE-PPE-EspG complex from Mycobacterium tuberculosis reveals molecular specificity of ESX protein secretion

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

Ekiert, Damian C.; Cox, Jeffery S.

Nearly 10% of the coding capacity of the Mycobacterium tuberculosis genome is devoted to two highly expanded and enigmatic protein families called PE and PPE, some of which are important virulence/immunogenicity factors and are secreted during infection via a unique alternative secretory system termed "type VII." How PE-PPE proteins function during infection and how they are translocated to the bacterial surface through the five distinct type VII secretion systems [ESAT-6 secretion system (ESX)] of M. tuberculosis is poorly understood. Here in this paper, we report the crystal structure of a PE-PPE heterodimer bound to ESX secretion-associated protein G (EspG), whichmore » adopts a novel fold. This PE-PPE-EspG complex, along with structures of two additional EspGs, suggests that EspG acts as an adaptor that recognizes specific PE-PPE protein complexes via extensive interactions with PPE domains, and delivers them to ESX machinery for secretion. Surprisingly, secretion of most PE-PPE proteins in M. tuberculosis is likely mediated by EspG from the ESX-5 system, underscoring the importance of ESX-5 in mycobacterial pathogenesis. Furthermore, our results indicate that PE-PPE domains function as cis-acting targeting sequences that are read out by EspGs, revealing the molecular specificity for secretion through distinct ESX pathways.« less

Structure of a PE-PPE-EspG complex from Mycobacterium tuberculosis reveals molecular specificity of ESX protein secretion

DOE PAGES

Ekiert, Damian C.; Cox, Jeffery S.

2014-10-01

Nearly 10% of the coding capacity of the Mycobacterium tuberculosis genome is devoted to two highly expanded and enigmatic protein families called PE and PPE, some of which are important virulence/immunogenicity factors and are secreted during infection via a unique alternative secretory system termed "type VII." How PE-PPE proteins function during infection and how they are translocated to the bacterial surface through the five distinct type VII secretion systems [ESAT-6 secretion system (ESX)] of M. tuberculosis is poorly understood. Here in this paper, we report the crystal structure of a PE-PPE heterodimer bound to ESX secretion-associated protein G (EspG), whichmore » adopts a novel fold. This PE-PPE-EspG complex, along with structures of two additional EspGs, suggests that EspG acts as an adaptor that recognizes specific PE-PPE protein complexes via extensive interactions with PPE domains, and delivers them to ESX machinery for secretion. Surprisingly, secretion of most PE-PPE proteins in M. tuberculosis is likely mediated by EspG from the ESX-5 system, underscoring the importance of ESX-5 in mycobacterial pathogenesis. Furthermore, our results indicate that PE-PPE domains function as cis-acting targeting sequences that are read out by EspGs, revealing the molecular specificity for secretion through distinct ESX pathways.« less

32 CFR 2001.46 - Transmission.

Code of Federal Regulations, 2010 CFR

2010-07-01

... between the U.S., Puerto Rico, or a U.S. possession or trust territory. (1) Top Secret. Top Secret... an authorized government agency courier service; a designated courier or escort with Top Secret clearance; electronic means over approved communications systems. Under no circumstances will Top Secret...

PROGRESS IN CLINICAL ENCAPSULATED ISLET XENOTRANSPLANTATION

PubMed Central

Cooper, David K.C.; Matsumoto, Shinichi; Abalovich, Adrian; Itoh, Takeshi; Mourad, Nizar I.; Gianello, Pierre R; Wolf, Eckhard; Cozzi, Emanuele

2016-01-01

At the 2015 combined congress of the CTS, IPITA, and IXA, a symposium was held to discuss recent progress in pig islet xenotransplantation. The presentations focused on 5 major topics – (i) the results of 2 recent clinical trials of encapsulated pig islet transplantation, (ii) the inflammatory response to encapsulated pig islets, (iii) methods to improve the secretion of insulin by pig islets, (iv) genetic modifications to the islet-source pigs aimed to protect the islets from the primate immune and/or inflammatory responses, and (v) regulatory aspects of clinical pig islet xenotransplantation. Trials of microencapsulated porcine islet transplantation to treat unstable type 1 diabetic patients have been associated with encouraging preliminary results. Further advances to improve efficacy may include (i) transplantation into a site other than the peritoneal cavity, which might result in better access to blood, oxygen, and nutrients; (ii) the development of a more biocompatible capsule and/or the minimization of a foreign body reaction; (iii) pig genetic modification to induce a greater secretion of insulin by the islets, and/or to reduce the immune response to islets released from damaged capsules; and (iv) reduction of the inflammatory response to the capsules/islets by improvements in the structure of the capsules and/or in genetic-engineering of the pigs and/or in some form of drug therapy. Ethical and regulatory frameworks for islet xenotransplantation are already available in several countries, and there is now a wider international perception of the importance of developing an internationally-harmonized ethical and regulatory framework. PMID:27482959

A translocator-specific export signal establishes the translocator-effector secretion hierarchy that is important for type III secretion system function

PubMed Central

Tomalka, Amanda G.; Stopford, Charles M.; Lee, Pei-Chung; Rietsch, Arne

2012-01-01

Summary Type III secretion systems are used by many Gram-negative pathogens to directly deliver effector proteins into the cytoplasm of host cells. To accomplish this, bacteria secrete translocator proteins that form a pore in the host-cell membrane through which the effector proteins are then introduced into the host cell. Evidence from multiple systems indicates that the pore-forming translocator proteins are exported before effectors, but how this secretion hierarchy is established is unclear. Here we used the P. aeruginosa translocator protein PopD as a model to identify its export signals. The amino-terminal secretion signal and chaperone, PcrH, are required for export under all conditions. Two novel signals in PopD, one proximal to the chaperone-binding site and one at the very C-terminus of the protein, are required for export of PopD before effector proteins. These novel export signals establish the translocator-effector secretion hierarchy, which in turn, is critical for the delivery of effectors into host cells. PMID:23121689

Extensive enrichment of N-glycolylneuraminic acid in extracellular sialoglycoproteins abundantly synthesized and secreted by human cancer cells.

PubMed

Inoue, Sadako; Sato, Chihiro; Kitajima, Ken

2010-06-01

N-Glycolylneuraminic acid (Neu5Gc) is the second most populous sialic acid (Sia). The only known biosynthetic pathway of Neu5Gc is the hydroxylation of cytidine-5'-monophosphate-N-acetylneuraminic acid (CMP-Neu5Ac), catalyzed by CMP-Neu5Ac hydroxylase (CMAH). Neu5Gc is abundantly found in mammals except for human, in which CMAH is inactivated due to mutation in the CMAH gene. Evidence has accumulated to show occurrence of Neu5Gc-containing glycoconjugates in sera of cancer patients, human cancerous tissues and cultured human cell lines. Recently, occurrence of natural antibodies against Neu5Gc was shown in healthy humans and is a serious problem for clinical xenotransplantation and stem cell therapies. Studying human occurrence of Neu5Gc is of importance and interest in a broad area of medical sciences. In this study, using a fluorometric high performance liquid chromatography method, we performed quantitative analyses of Sias both inside and in the external environment of the cell and found that (i) incorporation of Neu5Gc was most prominent in soluble glycoproteins found both in the extracellular space and inside the cell as the major Sia compounds. (ii) Of the total Neu5Gc in the Sia compounds that the cells synthesized, 90% was found in the secreted sialoglycoproteins, whereas for Neu5Ac, 70% was found in the secreted sialoglycoproteins. (iii) The Neu5Gc ratio was higher in the secreted sialoglycoproteins (as high as 40% of total Sias) than in intracellular sialoglycoproteins. (iv) The majority of the secreted sialoglycoproteins was anchored on the culture dishes and solubilized by brief trypsin treatment. Based on these findings, a new idea on the mechanism of accumulation of Neu5Gc in cancer cells was proposed.

Changes in membrane conductances and areas associated with bicarbonate secretion in turtle bladder.

PubMed

Rich, A; Dixon, T E; Clausen, C

1990-02-01

Transepithelial impedance-analysis studies were performed in turtle bladder epithelium in order to measure changes in the different epithelial membranes resulting from stimulation of electrogenic bicarbonate secretion. Changes in membrane conductance relate to changes in ionic permeability, whereas changes in membrane capacitance relate to changes in membrane area, since most biological membranes exhibit a specific capacitance of approximately 1 muF/cm2. The results of this investigation are summarized as follows: (i) cAMP and carbachol, agents which have been shown previously to stimulate electrogenic bicarbonate secretion, result in increases in apical-membrane conductance and capacitance; (ii) these changes occur concomitantly with the observed change in transport (measured using the short-circuit-current technique), thereby suggesting that bicarbonate secretion may be regulated in part by changes in the chloride conductance of the apical membrane; (iii) the increase in conductance does not reflect an increase in the membrane's specific conductance, thereby indicating that it results from the addition of membrane possessing similar ionic permeability as the existing apical membrane; (iv) the magnitude of the changes in capacitance indicate that a minor cell population (beta-type carbonic-anhydrase-rich cells) increase their apical-membrane area by several-fold; (v) a lack of transport-associated changes in the basolateral-membrane parameters suggest that transport is not regulated by alterations in basolateral-membrane ionic conductance or area; (vi) a lack of colchicine sensitivity, coupled with the magnitude of the changes in apical-membrane capacitance, indicate that the membrane remodeling processes are different from those involved in the regulation of proton secretion in a different cell population (alpha-type carbonic-anhydrase-rich cells).

Analysis of the 2-deoxy-D-glucose-induced vagal stimulation of gastric secretion and gastrin release in dogs using methionine-enkephalin, morphine and naloxone.

PubMed

Anderson, W; Molina, E; Rentz, J; Hirschowitz, B I

1982-09-01

Gastric acid and pepsin secreted in 3 hr and antral gastrin released in response to vagal excitation induced by 2-deoxy-D-glucose (2DG), 625 mumol/kg i.v., were studied in six conscious trained gastric fistula dogs. During a 2-hr infusion, Met-enkephalin (96 nmol/kg/hr; delta receptor) reduced the 2DG response by 50%; when the enkephalin was stopped there was a rapid rebound to peak values. Met-enkephalin also blocked the release of gastrin in the first 15 min. By itself, Met-enkephalin did not stimulate secretion and slightly depressed gastrin. By contrast, morphine (96 nmol/kg/hr; mu receptor) augmented and sustained the 2DG gastric acid secretory response. This effect was blocked by naloxone. Morphine alone caused a small rise in serum gastrin after 90 min, followed by a delayed gastric acid secretion of about 30% of the peak 2DG response. Naloxone, a mu opiate antagonist (mu/delta, 27:1), also inhibited the 2DG gastric secretory response by about 50% and augmented the Met-enkephalin inhibition of secretion without blocking either the secretory rebound or the effect on gastrin release. None of the three opiates changed the direct cholinergic gastric secretory or gastrin-releasing effects of bethanechol. Thus, vagal stimulation of the stomach involves pathways which can be influenced by both mu and delta opiates, with apparently opposite effects, proximal to the level of acetylcholine action on the gastric mucosa. The central and peripheral control points in the activation of the stomach via the vagus which are sensitive to opiates have yet to be located and explained.

Accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type III secretion systems

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

Samudrala, Ram; Heffron, Fred; McDermott, Jason E.

2009-04-24

The type III secretion system is an essential component for virulence in many Gram-negative bacteria. Though components of the secretion system apparatus are conserved, its substrates, effector proteins, are not. We have used a machine learning approach to identify new secreted effectors. The method integrates evolutionary measures, such as the pattern of homologs in a range of other organisms, and sequence-based features, such as G+C content, amino acid composition and the N-terminal 30 residues of the protein sequence. The method was trained on known effectors from Salmonella typhimurium and validated on a corresponding set of effectors from Pseudomonas syringae, aftermore » eliminating effectors with detectable sequence similarity. The method was able to identify all of the known effectors in P. syringae with a specificity of 84% and sensitivity of 82%. The reciprocal validation, training on P. syringae and validating on S. typhimurium, gave similar results with a specificity of 86% when the sensitivity level was 87%. These results show that type III effectors in disparate organisms share common features. We found that maximal performance is attained by including an N-terminal sequence of only 30 residues, which agrees with previous studies indicating that this region contains the secretion signal. We then used the method to define the most important residues in this putative secretion signal. Finally, we present novel predictions of secreted effectors in S. typhimurium, some of which have been experimentally validated, and apply the method to predict secreted effectors in the genetically intractable human pathogen Chlamydia trachomatis. This approach is a novel and effective way to identify secreted effectors in a broad range of pathogenic bacteria for further experimental characterization and provides insight into the nature of the type III secretion signal.« less

A Phytase-Based Reporter System for Identification of Functional Secretion Signals in Bifidobacteria

PubMed Central

Osswald, Annika; Westermann, Christina; Sun, Zhongke; Riedel, Christian U.

2015-01-01

Health-promoting effects have been attributed to a number of Bifidobacterium sp. strains. These effects as well as the ability to colonise the host depend on secreted proteins. Moreover, rational design of protein secretion systems bears the potential for the generation of novel probiotic bifidobacteria with improved health-promoting or therapeutic properties. To date, there is only very limited data on secretion signals of bifidobacteria available. Using in silico analysis, we demonstrate that all bifidobacteria encode the major components of Sec-dependent secretion machineries but only B. longum strains harbour Tat protein translocation systems. A reporter plasmid for secretion signals in bifidobacteria was established by fusing the coding sequence of the signal peptide of a sialidase of Bifidobacterium bifidum S17 to the phytase gene appA of E. coli. The recombinant strain showed increased phytase activity in spent culture supernatants and reduced phytase levels in crude extracts compared to the control indicating efficient phytase secretion. The reporter plasmid was used to screen seven predicted signal peptides in B. bifidum S17 and B. longum E18. The tested signal peptides differed substantially in their efficacy to mediate protein secretion in different host strains. An efficient signal peptide was used for expression and secretion of a therapeutically relevant protein in B. bifidum S17. Expression of a secreted cytosine deaminase led to a 100-fold reduced sensitivity of B. bifidum S17 to 5-fluorocytosine compared to the non-secreted cytosine deaminase suggesting efficient conversion of 5-fluorocytosine to the cytotoxic cancer drug 5-fluorouracil by cytosine deaminase occurred outside the bacterial cell. Selection of appropriate signal peptides for defined protein secretion might improve therapeutic efficacy as well as probiotic properties of bifidobacteria. PMID:26086721

oriTfinder: a web-based tool for the identification of origin of transfers in DNA sequences of bacterial mobile genetic elements.

PubMed

Li, Xiaobin; Xie, Yingzhou; Liu, Meng; Tai, Cui; Sun, Jingyong; Deng, Zixin; Ou, Hong-Yu

2018-05-04

oriTfinder is a web server that facilitates the rapid identification of the origin of transfer site (oriT) of a conjugative plasmid or chromosome-borne integrative and conjugative element. The utilized back-end database oriTDB was built upon more than one thousand known oriT regions of bacterial mobile genetic elements (MGEs) as well as the known MGE-encoding relaxases and type IV coupling proteins (T4CP). With a combination of similarity searches for the oriTDB-archived oriT nucleotide sequences and the co-localization of the flanking relaxase homologous genes, the oriTfinder can predict the oriT region with high accuracy in the DNA sequence of a bacterial plasmid or chromosome in minutes. The server also detects the other transfer-related modules, including the potential relaxase gene, T4CP gene and the type IV secretion system gene cluster, and the putative genes coding for virulence factors and acquired antibiotic resistance determinants. oriTfinder may contribute to meeting the increasing demands of re-annotations for bacterial conjugative, mobilizable or non-transferable elements and aid in the rapid risk accession of disease-relevant trait dissemination in pathogenic bacteria of interest. oriTfinder is freely available to all users without any login requirement at http://bioinfo-mml.sjtu.edu.cn/oriTfinder.

Molecular characterization of a functional type VI secretion system from a clinical isolate of Aeromonas hydrophila

EPA Science Inventory

Our laboratory recently molecularly characterized the type II secretion system (T2SS)-associated cytotoxic enterotoxin (Act) and the T3SS-secreted AexU effector from a diarrheal isolate SSU of Aeromonas hydrophila. The role of these toxin proteins in the pathogenesis of A. hydrop...

Molecular Characterization of a Functional Type VI Secretion System from a Clinical Isolate of Aeromonas hydrophilia

EPA Science Inventory

Our laboratory recently molecularly characterized the type II secretion system (T2SS)-associated cytotoxic enterotoxin (Act) and the T3SS-secreted AexU effector from a diarrheal isolate SSU of Aeromonas hydrophila. The role of these toxin proteins in the pathogenesis of A. hydrop...

A protein secretion system linked to bacteroidete gliding motility and pathogenesis

PubMed Central

Sato, Keiko; Naito, Mariko; Yukitake, Hideharu; Hirakawa, Hideki; Shoji, Mikio; McBride, Mark J.; Rhodes, Ryan G.; Nakayama, Koji

2009-01-01

Porphyromonas gingivalis secretes strong proteases called gingipains that are implicated in periodontal pathogenesis. Protein secretion systems common to other Gram-negative bacteria are lacking in P. gingivalis, but several proteins, including PorT, have been linked to gingipain secretion. Comparative genome analysis and genetic experiments revealed 11 additional proteins involved in gingipain secretion. Six of these (PorK, PorL, PorM, PorN, PorW, and Sov) were similar in sequence to Flavobacterium johnsoniae gliding motility proteins, and two others (PorX and PorY) were putative two-component system regulatory proteins. Real-time RT-PCR analysis revealed that porK, porL, porM, porN, porP, porT, and sov were down-regulated in P. gingivalis porX and porY mutants. Disruption of the F. johnsoniae porT ortholog resulted in defects in motility, chitinase secretion, and translocation of a gliding motility protein, SprB adhesin, to the cell surface, providing a link between a unique protein translocation system and a motility apparatus in members of the Bacteroidetes phylum. PMID:19966289

The I-V Measurement System for Solar Cells Based on MCU

NASA Astrophysics Data System (ADS)

Fengxiang, Chen; Yu, Ai; Jiafu, Wang; Lisheng, Wang

2011-02-01

In this paper, an I-V measurement system for solar cells based on Single-chip Microcomputer (MCU) is presented. According to the test principles of solar cells, this measurement system mainly comprises of two parts—data collecting, data processing and displaying. The MCU mainly used as to acquire data, then the collecting results is sent to the computer by serial port. The I-V measurement results of our test system are shown in the human-computer interaction interface based on our hardware circuit. By comparing the test results of our I-V tester and the results of other commercial I-V tester, we found errors for most parameters are less than 5%, which shows our I-V test result is reliable. Because the MCU can be applied in many fields, this I-V measurement system offers a simple prototype for portable I-V tester for solar cells.

Cholecystokinin receptor antagonism by peptidergic and non-peptidergic agents in rat pancreas.

PubMed Central

Dembinski, A; Jaworek, J; Konturek, P K; Konturek, S J; Warzecha, Z

1989-01-01

1. Graded doses of bombesin infused I.V. into conscious rats with chronic pancreatic fistulae induced a dose-dependent stimulation of protein secretion, similar to that obtained with caerulein. This stimulation does not appear to be mediated by cholecystokinin (CCK) receptors because peptidergic (CR-1409) and non-peptidergic (L-364718) CCK antagonists failed to affect protein secretion at a dose range which caused almost complete suppression of caerulein-induced pancreatic secretion. 2. Studies in vitro on isolated rat pancreatic acini revealed that caerulein, pentagastrin and bombesin all showed the same efficacy in their ability to stimulate amylase release. In contrast, CCK antagonists competitively inhibited amylase release induced by caerulein and pentagastrin but not by bombesin or urecholine, indicating that the latter two agents act directly on acinar cells via receptors which are separate from those involved in stimulation induced by caerulein and pentagastrin. 3. DNA synthesis, measured by the incorporation of [3H]thymidine into DNA, was significantly stimulated by caerulein, soybean trypsin inhibitor (FOY 305), pentagastrin and by bombesin in a dose-dependent manner. CCK receptor antagonists prevented stimulation of DNA synthesis induced by caerulein, FOY 305 and pentagastrin but not by bombesin. 4. This study indicates that bombesin strongly stimulates pancreatic enzyme secretion, with an efficacy similar to that of caerulein, and also exerts a potent growth-promoting action on the pancreas, both effects appearing to be mediated by mechanisms independent of the CCK receptors. PMID:2614728

45 CFR 310.40 - What requirements apply for accessing systems and records for monitoring Computerized Tribal IV-D...

Code of Federal Regulations, 2010 CFR

2010-10-01

... records for monitoring Computerized Tribal IV-D Systems and Office Automation? 310.40 Section 310.40... COMPUTERIZED TRIBAL IV-D SYSTEMS AND OFFICE AUTOMATION Accountability and Monitoring Procedures for... monitoring Computerized Tribal IV-D Systems and Office Automation? In accordance with Part 95 of this title...

Diverse C-Terminal Sequences Involved in Flavobacterium johnsoniae Protein Secretion

PubMed Central

Kulkarni, Surashree S.; Zhu, Yongtao; Brendel, Colton J.

2017-01-01

ABSTRACT Flavobacterium johnsoniae and many related bacteria secrete proteins across the outer membrane using the type IX secretion system (T9SS). Proteins secreted by T9SSs have amino-terminal signal peptides for export across the cytoplasmic membrane by the Sec system and carboxy-terminal domains (CTDs) targeting them for secretion across the outer membrane by the T9SS. Most but not all T9SS CTDs belong to the family TIGR04183 (type A CTDs). We functionally characterized diverse CTDs for secretion by the F. johnsoniae T9SS. Attachment of the CTDs from F. johnsoniae RemA, AmyB, and ChiA to the foreign superfolder green fluorescent protein (sfGFP) that had a signal peptide at the amino terminus resulted in secretion across the outer membrane. In each case, approximately 80 to 100 amino acids from the extreme carboxy termini were needed for efficient secretion. Several type A CTDs from distantly related members of the phylum Bacteroidetes functioned in F. johnsoniae, supporting the secretion of sfGFP by the F. johnsoniae T9SS. F. johnsoniae SprB requires the T9SS for secretion but lacks a type A CTD. It has a conserved C-terminal domain belonging to the family TIGR04131, which we refer to as a type B CTD. The CTD of SprB was required for its secretion, but attachment of C-terminal regions of SprB of up to 1,182 amino acids to sfGFP failed to result in secretion. Additional features outside the C-terminal region of SprB may be required for its secretion. IMPORTANCE Type IX protein secretion systems (T9SSs) are common in but limited to members of the phylum Bacteroidetes. Most proteins that are secreted by T9SSs have conserved carboxy-terminal domains that belong to the protein domain family TIGR04183 (type A CTDs) or TIGR04131 (type B CTDs). Here, we identify features of T9SS CTDs of F. johnsoniae that are required for protein secretion and demonstrate that type A CTDs from distantly related members of the phylum function with the F. johnsoniae T9SS to secrete the foreign protein sfGFP. In contrast, type B CTDs failed to target sfGFP for secretion, suggesting a more complex association with the T9SS. PMID:28396348

Continuous 24-hour intravenous infusion of recombinant human growth hormone (GH)-releasing hormone-(1-44)-amide augments pulsatile, entropic, and daily rhythmic GH secretion in postmenopausal women equally in the estrogen-withdrawn and estrogen-supplemented states.

PubMed

Evans, W S; Anderson, S M; Hull, L T; Azimi, P P; Bowers, C Y; Veldhuis, J D

2001-02-01

How estrogen amplifies GH secretion in the human is not known. The present study tests the clinical hypothesis that estradiol modulates the stimulatory actions of a primary GH feedforward signal, GHRH. To this end, we investigated the ability of short-term (7- to 12-day) supplementation with oral estradiol vs. placebo to modulate basal, pulsatile, entropic, and 24-h rhythmic GH secretion driven by a continuous iv infusion of recombinant human GHRH-(1--44)-amide vs. saline in nine healthy postmenopausal women. Volunteers underwent concurrent blood sampling every 10 min for 24 h on four occasions in a prospectively randomized, single blind, within-subject cross-over design (placebo/saline, placebo/GHRH, estradiol/saline, estradiol/GHRH). Intensively sampled serum GH concentrations were quantitated by ultrasensitive chemiluminescence assay. Basal, pulsatile, entropic (feedback-sensitive), and 24-h rhythmic modes of GH secretion were appraised by deconvolution analysis, the approximate entropy (ApEn) statistic, and cosine regression, respectively. ANOVA revealed that continuous iv infusion of GHRH in the estrogen-withdrawn (control) milieu 1) amplified individual basal (P = 0.00011) and pulsatile (P < 10(-13)) GH secretion rates by 12- and 11-fold, respectively; 2) augmented GH secretory burst mass and amplitude each by 10-fold (P < 10(-11)), without altering GH secretory burst frequency, duration, or half-life; 3) increased the disorderliness (ApEn) of GH release patterns (P = 0.0000002); 4) elevated the mesor (cosine mean) and amplitude of the 24-h rhythm in serum GH concentrations by nearly 30-fold (both P < 10(-12)); 5) induced a phase advance in the clocktime of the GH zenith (P = 0.021); and 6) evoked a new 24-h rhythm in GH secretory burst mass with a maximum at 0018 h GH (P < 10(-3)), while damping the mesor of the 24-h rhythm in GH interpulse intervals (P < 0.025). Estradiol supplementation alone 1) increased the 24-h mean and integrated serum GH concentration (P = 0.047); 2) augmented GH secretory burst mass (P: = 0.025) without influencing pulse frequency, duration, half-life, or basal secretion; 2) stimulated more irregular patterns of GH release (higher ApEn; P = 0.012); and 3) elevated the 24-h rhythmic GH mesor (P = 0.0005), but not amplitude. Notably, combined stimulation of the GH axis with GHRH-(1--44)-amide and estradiol exerted no further effect beyond that evoked by GHRH alone, except for normalizing the acrophase of 24-h GH rhythmic release and elevating the postinfusion plasma insulin-like growth factor I concentration (P = 0.016). Unexpectedly, the two GHRH-infused serum GH concentration profiles monitored after placebo and estradiol pretreatment showed strongly nonrandom synchrony with a 20- to 30-min lag (P < 0.001). In summary, the present clinical investigations unmask a 3-fold (pulsatile, entropic, and daily rhythmic) similitude between the neuroregulatory actions of estradiol and GHRH in healthy postmenopausal women. However, GHRH infusion was multifold more effectual than estradiol, and only GHRH elevated nonpulsatile (basal) GH secretion, shifted the GH acrophase, and synchronized GH profiles. Given the nonadditive nature of the joint effects of estradiol and GHRH on pulsatile and entropic GH release, we hypothesize that estrogen amplifies GH secretion in part by enhancing endogenous GHRH release or actions. In addition, the distinctive ability of GHRH (but not estradiol) to increase basal (nonpulsatile) GH secretion, shift the GH acrophase and synchronize GH output patterns identifies certain divergent hypothalamo-pituitary actions of these two major GH secretagogues.

Jejunal wall triglyceride concentration of morbidly obese persons is lower in those with type 2 diabetes mellitus

PubMed Central

Soriguer, F.; García-Serrano, S.; Garrido-Sánchez, L.; Gutierrez-Repiso, C.; Rojo-Martínez, G.; Garcia-Escobar, E.; García-Arnés, J.; Gallego-Perales, J. L.; Delgado, V.; García-Fuentes, Eduardo

2010-01-01

The overproduction of intestinal lipoproteins may contribute to the dyslipidemia found in diabetes. We studied the influence of diabetes on the fasting jejunal lipid content and its association with plasma lipids and the expression of genes involved in the synthesis and secretion of these lipoproteins. The study was undertaken in 27 morbidly obese persons, 12 of whom had type 2 diabetes mellitus (T2DM). The morbidly obese persons with diabetes had higher levels of chylomicron (CM) triglycerides (P < 0.001) and apolipoprotein (apo)B48 (P = 0.012). The jejunum samples obtained from the subjects with diabetes had a lower jejunal triglyceride content (P = 0.012) and angiopoietin-like protein 4 (ANGPTL4) mRNA expression (P = 0.043). However, the apoA-IV mRNA expression was significantly greater (P = 0.036). The jejunal triglyceride content correlated negatively with apoA-IV mRNA expression (r = −0.587, P = 0.027). The variables that explained the jejunal triglyceride content in a multiple linear regression model were the insulin resistance state and the apoA-IV mRNA expression. Our results show that the morbidly obese subjects with diabetes had lower jejunal lipid content and that this correlated negatively with apoA-IV mRNA expression. These findings show that the jejunum appears to play an active role in lipid homeostasis in the fasting state. PMID:20855567

Warfare between Host Immunity and Bacterial Weapons.

PubMed

Yu, Manda; Lai, Erh-Min

2017-01-11

Bacterial pathogens deploy protein secretion systems to facilitate infection and colonization of their hosts. In this issue of Cell Host & Microbe, Chen et al. (2017) report a new role for a type VI secretion effector in promoting bacterial colonization by preventing inflammasome activation induced by a type III secretion system. Copyright © 2017 Elsevier Inc. All rights reserved.

Trade Secret Law and Information Systems: Can Your Students Keep a Secret?

ERIC Educational Resources Information Center

Willey, Lorrie; Ford, Janet C.; White, Barbara Jo; Clapper, Danial L.

2011-01-01

The impact of intellectual property (IP) law on information systems (IS) professionals in business cannot be overstated. The IS 2010 model curriculum guidelines for undergraduate IS programs stress the importance of information security and knowledge about IP. While copyright and patents are the most well-known types of IP, another, trade secrets,…

Reversible increase in maximal cortisol secretion rate in septic shock.

PubMed

Dorin, Richard I; Qualls, Clifford R; Torpy, David J; Schrader, Ronald M; Urban, Frank K

2015-03-01

Cortisol clearance is reduced in sepsis and may contribute to the development of impaired adrenocortical function that is thought to contribute to the pathophysiology of critical illness-related corticosteroid insufficiency. We sought to assess adrenocortical function using computer-assisted numerical modeling methodology to characterize and compare maximal cortisol secretion rate and free cortisol half-life in septic shock, sepsis, and healthy control subjects. Post hoc analysis of previously published total cortisol, free cortisol, corticosteroid-binding globulin, and albumin concentration data. Single academic medical center. Subjects included septic shock (n = 45), sepsis (n = 25), and healthy controls (n = 10). I.v. cosyntropin (250 μg). Solutions for maximal cortisol secretion rate and free cortisol half-life were obtained by least squares solution of simultaneous, nonlinear differential equations that account for free cortisol appearance and elimination as well as reversible binding to corticosteroid-binding globulin and albumin. Maximal cortisol secretion rate was significantly greater in septic shock (0.83 nM/s [0.44, 1.58 nM/s] reported as median [lower quartile, upper quartile]) compared with sepsis (0.51 nM/s [0.36, 0.62 nM/s]; p = 0.007) and controls (0.49 nM/s [0.42, 0.62 nM/s]; p = 0.04). The variance of maximal cortisol secretion rate in septic shock was also greater than that of sepsis or control groups (F test, p < 0.001). Free cortisol half-life was significantly increased in septic shock (4.6 min [2.2, 6.3 min]) and sepsis (3.0 min [2.3, 4.8 min] when compared with controls (2.0 min [1.2, 2.6 min]) (both p < 0.004). Results obtained by numerical modeling are consistent with comparable measures obtained by the gold standard stable isotope dilution method. Septic shock is associated with generally not only higher levels but also greater variance of maximal cortisol secretion rate when compared with control and sepsis groups. Additional studies would be needed to determine whether assessment of cortisol kinetic parameters such as maximal cortisol secretion rate and free cortisol half-life is useful in the diagnosis or management of critical illness-related corticosteroid insufficiency.

Two-Partner Secretion: Combining Efficiency and Simplicity in the Secretion of Large Proteins for Bacteria-Host and Bacteria-Bacteria Interactions

PubMed Central

Guérin, Jeremy; Bigot, Sarah; Schneider, Robert; Buchanan, Susan K.; Jacob-Dubuisson, Françoise

2017-01-01

Initially identified in pathogenic Gram-negative bacteria, the two-partner secretion (TPS) pathway, also known as Type Vb secretion, mediates the translocation across the outer membrane of large effector proteins involved in interactions between these pathogens and their hosts. More recently, distinct TPS systems have been shown to secrete toxic effector domains that participate in inter-bacterial competition or cooperation. The effects of these systems are based on kin vs. non-kin molecular recognition mediated by specific immunity proteins. With these new toxin-antitoxin systems, the range of TPS effector functions has thus been extended from cytolysis, adhesion, and iron acquisition, to genome maintenance, inter-bacterial killing and inter-bacterial signaling. Basically, a TPS system is made up of two proteins, the secreted TpsA effector protein and its TpsB partner transporter, with possible additional factors such as immunity proteins for protection against cognate toxic effectors. Structural studies have indicated that TpsA proteins mainly form elongated β helices that may be followed by specific functional domains. TpsB proteins belong to the Omp85 superfamily. Open questions remain on the mechanism of protein secretion in the absence of ATP or an electrochemical gradient across the outer membrane. The remarkable dynamics of the TpsB transporters and the progressive folding of their TpsA partners at the bacterial surface in the course of translocation are thought to be key elements driving the secretion process. PMID:28536673

Variations of System IV period of the sulfur ions in the Io torus for the volcanic event in 2015 observed by the HISAKI/EXCEED

NASA Astrophysics Data System (ADS)

Ryo, A.; Misawa, H.; Tsuchiya, F.; Kagitani, M.; Yoshioka, K.; Yoshikawa, I.; Kimura, T.; Murakami, G.; Yamazaki, A.

2017-12-01

Previous ground-based and probe observations of Io plasma torus (IPT) in various wavelengths have detected a periodic variation which is longer than System III period (9.925 h). It has been called System IV period. Although various ideas to explain the origin of System IV period are proposed , little progress has been made. A previous study reported that the System IV period was 10.07 h during the Cassini's Jupiter flyby in 2000. This period was shorter than the typical period of 10.21h (Brown 1995). The Io's volcanic event just before Cassini's flyby might shorten the System IV period (Steffl et al., 2006). However, the certainty of this inference is not clear from the Cassini observation. Here, we analyzed time variations in intensities of EUV emissions from IPT obtained by the HISAKI satellite to understand the mechanism responsible for the System IV period and the influence of Io's volcanic event on IPT. The data used in this study was obtained from Dec. 2014 to the middle of May 2015. During this period, the Io's volcanic event from Jan. to Mar. 2015 was reported from the observation of Iogenic sodium emission (Yoneda et al., 2015). To find variations of the System IV period, the temporal variation of System III longitude at peak EUV intensity was derived by fitting light curves of three ion species (S II 76.5 nm + 126 nm, S III 68 nm, and S IV 65.7 nm + 140.5 nm). The System IV periods of S II before and after the Io's volcanic event were 10.16±0.008 h and 10.03±0.006 h, respectively. On the other hands, the System IV period of S II was 9.95±0.003 h during the Io's volcanic event. This is the first observational evidence which shows that the System IV period has shortened during the Io's volcanic event, which is consistent with the result from Cassini observation. Origin of the System IV period has been discussed with sub-corotation of plasma in IPT. Since the sub-corotation occurs due to mass loading of newly picked-up ions into IPT, it is expected that the System IV period becomes long during Io's volcanic event. However, the result shows the opposite feature and will give important information to constrain the origin of the System IV period. To verify above consideration, we will derive time variation in plasma parameters in IPT from the HISAKI data with plasma diagnosis analysis. This analysis will enable us to constrain the origin of the System IV period.

Coxiella burnetii Employs the Dot/Icm Type IV Secretion System to Modulate Host NF-κB/RelA Activation

PubMed Central

Mahapatra, Saugata; Gallaher, Brandi; Smith, Sydni Caet; Graham, Joseph G.; Voth, Daniel E.; Shaw, Edward I.

2016-01-01

Coxiella burnetii is the causative agent of Q fever and an obligate intracellular pathogen in nature that survives and grows in a parasitophorous vacuole (PV) within eukaryotic host cells. C. burnetii promotes intracellular survival by subverting apoptotic and pro-inflammatory signaling pathways that are typically regulated by nuclear transcription factor-κB (NF-κB). We and others have demonstrated that C. burnetii NMII proteins inhibit expression of pro-inflammatory cytokines and induce expression of anti-apoptotic genes during infection. Here, we demonstrate that C. burnetii promotes intracellular survival by modulating NF-κB subunit p65 (RelA) phosphorylation, and thus activation, in a Type Four B Secretion System (T4BSS)-dependent manner. Immunoblot analysis of RelA phosphorylated at serine-536 demonstrated that C. burnetii increases NF-κB activation via the canonical pathway. However, RelA phosphorylation levels were even higher in infected cells where bacterial protein or mRNA synthesis was inhibited. Importantly, we demonstrate that inhibition of RelA phosphorylation impairs PV formation and C. burnetii growth. We found that a T4BSS-defective mutant (CbΔdotA) elicited phosphorylated RelA levels similar to those of wild type C. burnetii infection treated with Chloramphenicol. Moreover, cells infected with CbΔdotA or wild type C. burnetii treated with Chloramphenicol showed similar levels of GFP-RelA nuclear localization, and significantly increased localization compared to wild type C. burnetii infection. These data indicate that without de novo protein synthesis and a functional T4BSS, C. burnetii is unable to modulate NF-κB activation, which is crucial for optimal intracellular growth. PMID:28066723

Pharmacologic antagonism of thromboxane A2 receptors by trimetoquinol analogs in vitro and in vivo

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

Shin, Y.; Romstedt, K.J.; Doyle, K.

1991-01-01

Although (-)-(S)-trimetoquinol (1-(3,4,5-trimethoxy-benzyl)- 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline; TMQ) is recognized as a potent bronchodilator, (+)-(R)-TMQ is a selective antagonist of human platelet aggregation and serotonin secretion induced by thromboxane A2 (TXA2) agonists. To confirm the pharmacological actions of TMQ analogs, the interaction of the drugs with TXA2 receptors was examined in human platelets and in a mouse sudden death model. The inhibitory potencies of TMQ analogs (pIC50 values) for displacement of (3H)SQ 29,548 binding to platelets showed excellent correlation with the respective pIC50 (-log IC50) values for U46619-induced aggregation (r = 0.99, P less than 0.01) and serotonin secretion (r = 0.99, Pmore » less than 0.01) in human platelet-rich plasma and for whole blood aggregation (r = 0.99, P less than 0.01). In each system, the rank order of inhibitory potencies was rac-iodoTMQ greater than or equal to (+)-(R)-TMQ greater than rac-TMQ much greater than (-)-(S)-TMQ. Antithrombotic effects of TMQ analogs were evaluated in a mouse sudden death model. In vivo antithrombotic potencies of these compounds were consistent with the in vitro potencies as TXA2 receptor antagonists in platelet systems. Administration of rac-iodoTMQ, (+)-(R)-TMQ and rac-TMQ 15 min before the injection of U46619 (800 micrograms/kg, iv) protected mice against U46619-induced sudden death. On the other hand, (-)-(S)-TMQ did not protect animals against death. Protection of U46619-induced cardiopulmonary thrombosis by TMQ analogs was seen at doses of 3-100 mg/kg.« less

Controlled Bidirectional Quantum Secure Direct Communication

PubMed Central

Chou, Yao-Hsin; Lin, Yu-Ting; Zeng, Guo-Jyun; Lin, Fang-Jhu; Chen, Chi-Yuan

2014-01-01

We propose a novel protocol for controlled bidirectional quantum secure communication based on a nonlocal swap gate scheme. Our proposed protocol would be applied to a system in which a controller (supervisor/Charlie) controls the bidirectional communication with quantum information or secret messages between legitimate users (Alice and Bob). In this system, the legitimate users must obtain permission from the controller in order to exchange their respective quantum information or secret messages simultaneously; the controller is unable to obtain any quantum information or secret messages from the decoding process. Moreover, the presence of the controller also avoids the problem of one legitimate user receiving the quantum information or secret message before the other, and then refusing to help the other user decode the quantum information or secret message. Our proposed protocol is aimed at protecting against external and participant attacks on such a system, and the cost of transmitting quantum bits using our protocol is less than that achieved in other studies. Based on the nonlocal swap gate scheme, the legitimate users exchange their quantum information or secret messages without transmission in a public channel, thus protecting against eavesdroppers stealing the secret messages. PMID:25006596

Secret Sharing and Shared Information

NASA Astrophysics Data System (ADS)

Rauh, Johannes

2017-11-01

Secret sharing is a cryptographic discipline in which the goal is to distribute information about a secret over a set of participants in such a way that only specific authorized combinations of participants together can reconstruct the secret. Thus, secret sharing schemes are systems of variables in which it is very clearly specified which subsets have information about the secret. As such, they provide perfect model systems for information decompositions. However, following this intuition too far leads to an information decomposition with negative partial information terms, which are difficult to interpret. One possible explanation is that the partial information lattice proposed by Williams and Beer is incomplete and has to be extended to incorporate terms corresponding to higher order redundancy. These results put bounds on information decompositions that follow the partial information framework, and they hint at where the partial information lattice needs to be improved.

Secret Key Generation via a Modified Quantum Secret Sharing Protocol

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

Smith IV, Amos M; Evans, Philip G; Lawrie, Benjamin J

We present and experimentally show a novel protocol for distributing secret information between two and only two parties in a N-party single-qubit Quantum Secret Sharing (QSS) system. We demonstrate this new algorithm with N = 3 active parties over 6km of telecom. ber. Our experimental device is based on the Clavis2 Quantum Key Distribution (QKD) system built by ID Quantique but is generalizable to any implementation. We show that any two out of the N parties can build secret keys based on partial information from each other and with collaboration from the remaining N > 2 parties. This algorithm allowsmore » for the creation of two-party secret keys were standard QSS does not and signicantly reduces the number of resources needed to implement QKD on a highly connected network such as the electrical grid.« less

Double mutation of cell wall proteins CspB and PBP1a increases secretion of the antibody Fab fragment from Corynebacterium glutamicum

PubMed Central

2014-01-01

Background Among other advantages, recombinant antibody-binding fragments (Fabs) hold great clinical and commercial potential, owing to their efficient tissue penetration compared to that of full-length IgGs. Although production of recombinant Fab using microbial expression systems has been reported, yields of active Fab have not been satisfactory. We recently developed the Corynebacterium glutamicum protein expression system (CORYNEX®) and demonstrated improved yield and purity for some applications, although the system has not been applied to Fab production. Results The Fab fragment of human anti-HER2 was successfully secreted by the CORYNEX® system using the conventional C. glutamicum strain YDK010, but the productivity was very low. To improve the secretion efficiency, we investigated the effects of deleting cell wall-related genes. Fab secretion was increased 5.2 times by deletion of pbp1a, encoding one of the penicillin-binding proteins (PBP1a), mediating cell wall peptidoglycan (PG) synthesis. However, this Δpbp1a mutation did not improve Fab secretion in the wild-type ATCC13869 strain. Because YDK010 carries a mutation in the cspB gene encoding a surface (S)-layer protein, we evaluated the effect of ΔcspB mutation on Fab secretion from ATCC13869. The Δpbp1a mutation showed a positive effect on Fab secretion only in combination with the ΔcspB mutation. The ΔcspBΔpbp1a double mutant showed much greater sensitivity to lysozyme than either single mutant or the wild-type strain, suggesting that these mutations reduced cell wall resistance to protein secretion. Conclusion There are at least two crucial permeability barriers to Fab secretion in the cell surface structure of C. glutamicum, the PG layer, and the S-layer. The ΔcspBΔpbp1a double mutant allows efficient Fab production using the CORYNEX® system. PMID:24731213

An Analysis of Perturbed Quantization Steganography in the Spatial Domain

DTIC Science & Technology

2005-03-01

72 4.2.3 Hide v2.1 Steganographic Software & the Desaturate Function. ..................... 73 4.2.4 Studying the Effect of the Secret Message...Effect of the Secret Message Payload.......................................... 84 4.3.4 Performance Comparison of the Three Steganographic Systems...Epsilon .......................................................................... 89 4.4 Secrets for the Secret ............................................................................................... 90

Verifying Secrets and Relative Secrecy

DTIC Science & Technology

2000-01-01

Systems that authenticate a user based on a shared secret (such as a password or PIN) normally allow anyone to query whether the secret is a given...value. For example, an ATM machine allows one to ask whether a string is the secret PIN of a (lost or stolen) ATM card. Yet such queries are prohibited

A Bacterial Pathogen uses Distinct Type III Secretion Systems to Alternate between Host Kingdom

USDA-ARS?s Scientific Manuscript database

Gram-negative bacterial pathogens of eukaryotes often secrete proteins directly into host cells via a needle-like protein channel called a ‘type III secretion system’ (T3SS). Bacteria that are adapted to either animal or plant hosts use phylogenetically distinct T3SSs for secreting proteins. Here, ...

Use of radioguided surgery with [111In]-pentetreotide in the management of an ACTH-secreting bronchial carcinoid causing ectopic Cushing's syndrome.

PubMed

Grossrubatscher, E; Vignati, F; Dalino, P; Possa, M; Belloni, P A; Vanzulli, A; Bramerio, M; Marocchi, A; Rossetti, O; Zurleni, F; Loli, P

2005-01-01

Intraoperative [111In]-pentetreotide scintigraphy with a hand-held gamma detector probe has recently been proposed to increase the intraoperative detection rate of small neuroendocrine tumors and their metastases. We report a case of a 28-yr-old woman with ectopic Cushing's syndrome due to an ACTH-secreting bronchial carcinoid, in whom the use of radioguided surgery improved disease management. At presentation, radiolabeled pentetreotide scintigraphy was the only procedure able to detect the ectopic source of ACTH. After radiologic confirmation, the patient underwent removal of a bronchial carcinoid, with disease persistence. After surgery, pentetreotide scintigraphy showed pathologic uptake in the mediastinum not previously detected at surgery and only subsequently confirmed by radiologic studies. Despite a second thoracic exploration, hormonal, scintigraphic, and radiological evidence of residual disease persisted. Radioguided surgery was then performed using a hand-held gamma probe 48 h after iv administration of a tracer dose of radiolabeled [111In-DTPA-D-Phe1]-pentetreotide, which permitted detection and removal of multiple residual mediastinal lymph node metastases. Clinical and radiologic cure, with no evidence of tracer uptake at pentetreotide scintigraphy, was subsequently observed. The use of an intraoperative gamma counter appears a promising procedure in the management of metastatic ACTH-secreting bronchial carcinoids.

Development of Methodologies for IV and V of Neural Networks

NASA Technical Reports Server (NTRS)

Taylor, Brian; Darrah, Marjorie

2003-01-01

Non-deterministic systems often rely upon neural network (NN) technology to "lean" to manage flight systems under controlled conditions using carefully chosen training sets. How can these adaptive systems be certified to ensure that they will become increasingly efficient and behave appropriately in real-time situations? The bulk of Independent Verification and Validation (IV&V) research of non-deterministic software control systems such as Adaptive Flight Controllers (AFC's) addresses NNs in well-behaved and constrained environments such as simulations and strict process control. However, neither substantive research, nor effective IV&V techniques have been found to address AFC's learning in real-time and adapting to live flight conditions. Adaptive flight control systems offer good extensibility into commercial aviation as well as military aviation and transportation. Consequently, this area of IV&V represents an area of growing interest and urgency. ISR proposes to further the current body of knowledge to meet two objectives: Research the current IV&V methods and assess where these methods may be applied toward a methodology for the V&V of Neural Network; and identify effective methods for IV&V of NNs that learn in real-time, including developing a prototype test bed for IV&V of AFC's. Currently. no practical method exists. lSR will meet these objectives through the tasks identified and described below. First, ISR will conduct a literature review of current IV&V technology. TO do this, ISR will collect the existing body of research on IV&V of non-deterministic systems and neural network. ISR will also develop the framework for disseminating this information through specialized training. This effort will focus on developing NASA's capability to conduct IV&V of neural network systems and to provide training to meet the increasing need for IV&V expertise in such systems.

Trimeric autotransporter adhesins contribute to Actinobacillus pleuropneumoniae pathogenicity in mice and regulate bacterial gene expression during interactions between bacteria and porcine primary alveolar macrophages.

PubMed

Qin, Wanhai; Wang, Lei; Zhai, Ruidong; Ma, Qiuyue; Liu, Jianfang; Bao, Chuntong; Zhang, Hu; Sun, Changjiang; Feng, Xin; Gu, Jingmin; Du, Chongtao; Han, Wenyu; Langford, P R; Lei, Liancheng

2016-01-01

Actinobacillus pleuropneumoniae is an important pathogen that causes respiratory disease in pigs. Trimeric autotransporter adhesin (TAA) is a recently discovered bacterial virulence factor that mediates bacterial adhesion and colonization. Two TAA coding genes have been found in the genome of A. pleuropneumoniae strain 5b L20, but whether they contribute to bacterial pathogenicity is unclear. In this study, we used homologous recombination to construct a double-gene deletion mutant, ΔTAA, in which both TAA coding genes were deleted and used it in in vivo and in vitro studies to confirm that TAAs participate in bacterial auto-aggregation, biofilm formation, cell adhesion and virulence in mice. A microarray analysis was used to determine whether TAAs can regulate other A. pleuropneumoniae genes during interactions with porcine primary alveolar macrophages. The results showed that deletion of both TAA coding genes up-regulated 36 genes, including ene1514, hofB and tbpB2, and simultaneously down-regulated 36 genes, including lgt, murF and ftsY. These data illustrate that TAAs help to maintain full bacterial virulence both directly, through their bioactivity, and indirectly by regulating the bacterial type II and IV secretion systems and regulating the synthesis or secretion of virulence factors. This study not only enhances our understanding of the role of TAAs but also has significance for those studying A. pleuropneumoniae pathogenesis.

45 CFR 310.15 - What are the safeguards and processes that comprehensive Tribal IV-D agencies must have in place...

Code of Federal Regulations, 2010 CFR

2010-10-01

... IV-D Systems and Office Automation? 310.15 Section 310.15 Public Welfare Regulations Relating to... AND OFFICE AUTOMATION Requirements for Computerized Tribal IV-D Systems and Office Automation § 310.15... ensure the security and privacy of Computerized Tribal IV-D Systems and Office Automation? (a...

Device Performance Capabilities | Photovoltaic Research | NREL

Science.gov Websites

multijunction cells and modules. We use I-V measurement systems to assess the main performance parameters for PV cells and modules. I-V measurement systems determine the output performance of devices, including: open the device (η). Some I-V systems may also be used to perform dark I-V measurements to determine diode

Identification of secreted bacterial proteins by noncanonical amino acid tagging

PubMed Central

Mahdavi, Alborz; Szychowski, Janek; Ngo, John T.; Sweredoski, Michael J.; Graham, Robert L. J.; Hess, Sonja; Schneewind, Olaf; Mazmanian, Sarkis K.; Tirrell, David A.

2014-01-01

Pathogenic microbes have evolved complex secretion systems to deliver virulence factors into host cells. Identification of these factors is critical for understanding the infection process. We report a powerful and versatile approach to the selective labeling and identification of secreted pathogen proteins. Selective labeling of microbial proteins is accomplished via translational incorporation of azidonorleucine (Anl), a methionine surrogate that requires a mutant form of the methionyl-tRNA synthetase for activation. Secreted pathogen proteins containing Anl can be tagged by azide-alkyne cycloaddition and enriched by affinity purification. Application of the method to analysis of the type III secretion system of the human pathogen Yersinia enterocolitica enabled efficient identification of secreted proteins, identification of distinct secretion profiles for intracellular and extracellular bacteria, and determination of the order of substrate injection into host cells. This approach should be widely useful for the identification of virulence factors in microbial pathogens and the development of potential new targets for antimicrobial therapy. PMID:24347637

Active phytochemicals of Pueraria tuberosa for DPP-IV inhibition: in silico and experimental approach.

PubMed

Srivastava, Shivani; Shree, Priya; Tripathi, Yamini Bhusan

2017-01-01

We had earlier reported that the extract of Pueraria tuberosa significantly inhibits DPP-IV enzyme, resulting in glucose tolerance response in rats. In this study, we have explored the active phytochemicals responsible for this potential. The results have been validated in both fasting and postprandial states in the plasma of normal rats and also in fasting blood and intestinal homogenates of diabetic models. Pueraria tuberosa water extract (PTWE) was administered to normal Charles Foster rats for 35 days and to diabetic model (65 mg/kg bw) for 10 days. After treatments, oral glucose tolerance test (OGTT) and insulin was done for 90 min, and the changes in the levels of GLP-1, GIP, and DPP-IV activities were monitored in fasting and postprandial states. In the case of the diabetic model, DPP-IV activity was measured in intestinal homogenate and basal insulin in plasma. The components of PTWE were analyzed via HPLC-MS based on their chemical formula, molecular mass, and retention time. Using the molecular docking study, we have selected the top five components having strong binding energy with DPP-IV. The increase in secretion of GLP-1 and GIP was significantly higher in the postprandial state when compared to fasting condition. GLP-1 plasma concentration increased by 5.8 and 2.9 folds and GIP increased by 8.7 and 2.4 folds in PTWE and control rats, respectively. In contrast, the postprandial decrease in DPP-IV specific activities was recorded at 2.3 and 1.4 folds. The response in OGTT and insulin was also consistent with these changes. In comparison to diabetic controls, PTWE-administered rats showed decreased DPP-IV activity in the intestine, leading to enhanced basal insulin concentration. Through molecular docking, we found Puerarone and Robinin to be the most potential phytochemicals of PTWE for DPP-IV inhibition. Binding energy (kcal/mol) and dissociation constant (pM) of Robinin with DPP-IV protein were found to be 7.543 and 2,957,383.75, respectively. For Puerarone, it was 7.376 and 3,920,309, respectively. Thus, this study provides the novel active components that contribute to the DPP-IV inhibitory property of PTWE.

The Correlated Variations of {\\rm{C}}\\,{\\rm{IV}} Narrow Absorption Lines and Quasar Continuum

NASA Astrophysics Data System (ADS)

Chen, Zhi-Fu; Pang, Ting-Ting; He, Bing; Huang, Yong

2018-06-01

We assemble 207 variable quasars from the Sloan Digital Sky Survey, all with at least 3 observations, to analyze C IV narrow absorption doublets, and obtain 328 C IV narrow absorption line systems. We find that 19 out of 328 C IV narrow absorption line systems were changed by | {{Δ }}{W}rλ 1548| ≥slant 3{σ }{{Δ }{W}rλ 1548} on timescales from 15.9 to 1477 days at rest-frame. Among the 19 obviously variable C IV systems, we find that (1) 14 systems have relative velocities {\\upsilon }r> 0.01c and 4 systems have {\\upsilon }r> 0.1c, where c is the speed of light; (2) 13 systems are accompanied by other variable C IV systems; (3) 9 systems were changed continuously during multiple observations; and (4) 1 system with {\\upsilon }r = 16,862 km s‑1 was enhanced by {{Δ }}{W}rλ 1548=2.7{σ }{{Δ }{W}rλ 1548} in 0.67 day at rest-frame. The variations of absorption lines are inversely correlated with the changes in the ionizing continuum. We also find that large variations of C IV narrow absorption lines are form differently over a short timescale.

Forced swimming-induced oxytocin release into blood and brain: Effects of adrenalectomy and corticosterone treatment.

PubMed

Torner, Luz; Plotsky, Paul M; Neumann, Inga D; de Jong, Trynke R

2017-03-01

The oxytocin (OXT) system is functionally linked to the HPA axis in a reciprocal and complex manner. Certain stressors are known to cause the simultaneous release of OXT and adrenocorticotrophic hormone (ACTH) followed by corticosterone (CORT). Furthermore, brain OXT attenuates ACTH and CORT responses. Although there are some indications of CORT influencing OXT neurotransmission, specific effects of CORT on neurohypophyseal or intra-hypothalamic release of OXT have not been studied in detail. In the present set of experiments, adult male rats were adrenalectomized (ADX) or sham-operated and fitted with a jugular vein catheter and/or microdialysis probe targeting the hypothalamic paraventricular nucleus (PVN). Blood samples and dialysates were collected before and after forced swimming (FS) and analyzed for CORT, ACTH and AVP concentrations (in plasma) and OXT concentrations (in plasma and dialysates). Experimental treatments included acute infusion of CORT (70 or 175μg/kg i.v.) 5min prior to FS, or subcutaneous placement of 40% CORT pellets resulting in stable CORT levels in the normal basal range. Although ADX did not alter basal OXT concentrations either in plasma or in microdialysates from the PVN, it did cause an exaggerated peripheral secretion of OXT and a blunted intra-PVN release of OXT in response to FS. CORT pellets did not influence either of these ADX-induced effects, while acute infusion of 175μg/kg CORT rescued the stress-induced rise in OXT release within the PVN and modestly increased peripheral OXT secretion. In conclusion, these results indicate that CORT regulates both peripheral and intracerebral OXT release, but in an independent manner. Whereas the peripheral secretion of OXT occurs simultaneously to HPA axis activation in response to FS and is modestly influenced by CORT, HPA axis activation and circulating CORT strongly contribute to the stress-induced stimulation of OXT release within the PVN. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pluripotency and a secretion mechanism of Drosophila transglutaminase.

PubMed

Shibata, Toshio; Kawabata, Shun-Ichiro

2018-03-01

Transglutaminase (TG) catalyses the formation of an isopeptide bond between glutamine and lysine residues and amine incorporation into specific glutamine residues. TG is conserved in all metazoans and functions both intracellularly and extracellularly. Here we review the existing knowledge of Drosophila TG with an emphasis on its pluripotency: Drosophila TG (i) plays a key role in cuticular morphogenesis, haemolymph coagulation, and entrapment against invading pathogens, (ii) suppresses the immune deficiency pathway to enable immune tolerance against commensal bacteria through the incorporation of polyamines into the nuclear factor-κB-like transcription factor Relish as well as through the protein-protein cross-linking of Relish, (iii) forms a physical matrix in the gut through cross-linking of chitin-binding proteins and (iv) is involved in the maintenance of homeostasis in microbiota in the gut. Moreover, we review the evidence that TG-A, one of alternative splicing-derived isoforms of Drosophila TG, is secreted through an endoplasmic reticulum/Golgi-independent pathway involving exosomes and fatty acylations.

Kin cell lysis is a danger signal that activates antibacterial pathways of Pseudomonas aeruginosa

PubMed Central

LeRoux, Michele; Kirkpatrick, Robin L; Montauti, Elena I; Tran, Bao Q; Peterson, S Brook; Harding, Brittany N; Whitney, John C; Russell, Alistair B; Traxler, Beth; Goo, Young Ah; Goodlett, David R; Wiggins, Paul A; Mougous, Joseph D

2015-01-01

The perception and response to cellular death is an important aspect of multicellular eukaryotic life. For example, damage-associated molecular patterns activate an inflammatory cascade that leads to removal of cellular debris and promotion of healing. We demonstrate that lysis of Pseudomonas aeruginosa cells triggers a program in the remaining population that confers fitness in interspecies co-culture. We find that this program, termed P. aeruginosa response to antagonism (PARA), involves rapid deployment of antibacterial factors and is mediated by the Gac/Rsm global regulatory pathway. Type VI secretion, and, unexpectedly, conjugative type IV secretion within competing bacteria, induce P. aeruginosa lysis and activate PARA, thus providing a mechanism for the enhanced capacity of P. aeruginosa to target bacteria that elaborate these factors. Our finding that bacteria sense damaged kin and respond via a widely distributed pathway to mount a complex response raises the possibility that danger sensing is an evolutionarily conserved process. DOI: http://dx.doi.org/10.7554/eLife.05701.001 PMID:25643398

The transcriptomic fingerprint of glucoamylase over-expression in Aspergillus niger

PubMed Central

2012-01-01

Background Filamentous fungi such as Aspergillus niger are well known for their exceptionally high capacity for secretion of proteins, organic acids, and secondary metabolites and they are therefore used in biotechnology as versatile microbial production platforms. However, system-wide insights into their metabolic and secretory capacities are sparse and rational strain improvement approaches are therefore limited. In order to gain a genome-wide view on the transcriptional regulation of the protein secretory pathway of A. niger, we investigated the transcriptome of A. niger when it was forced to overexpression the glaA gene (encoding glucoamylase, GlaA) and secrete GlaA to high level. Results An A. niger wild-type strain and a GlaA over-expressing strain, containing multiple copies of the glaA gene, were cultivated under maltose-limited chemostat conditions (specific growth rate 0.1 h-1). Elevated glaA mRNA and extracellular GlaA levels in the over-expressing strain were accompanied by elevated transcript levels from 772 genes and lowered transcript levels from 815 genes when compared to the wild-type strain. Using GO term enrichment analysis, four higher-order categories were identified in the up-regulated gene set: i) endoplasmic reticulum (ER) membrane translocation, ii) protein glycosylation, iii) vesicle transport, and iv) ion homeostasis. Among these, about 130 genes had predicted functions for the passage of proteins through the ER and those genes included target genes of the HacA transcription factor that mediates the unfolded protein response (UPR), e.g. bipA, clxA, prpA, tigA and pdiA. In order to identify those genes that are important for high-level secretion of proteins by A. niger, we compared the transcriptome of the GlaA overexpression strain of A. niger with six other relevant transcriptomes of A. niger. Overall, 40 genes were found to have either elevated (from 36 genes) or lowered (from 4 genes) transcript levels under all conditions that were examined, thus defining the core set of genes important for ensuring high protein traffic through the secretory pathway. Conclusion We have defined the A. niger genes that respond to elevated secretion of GlaA and, furthermore, we have defined a core set of genes that appear to be involved more generally in the intensified traffic of proteins through the secretory pathway of A. niger. The consistent up-regulation of a gene encoding the acetyl-coenzyme A transporter suggests a possible role for transient acetylation to ensure correct folding of secreted proteins. PMID:23237452

Polyethyleneimine and Chitosan Polymer-Based Mucoadhesive Liquid Crystalline Systems Intended for Buccal Drug Delivery.

PubMed

Calixto, Giovana Maria Fioramonti; Victorelli, Francesca Damiani; Dovigo, Lívia Nordi; Chorilli, Marlus

2018-02-01

The buccal mucosa is accessible, shows rapid repair, has an excellent blood supply, and shows the absence of the first-pass effect, which makes it a very attractive drug delivery route. However, this route has limitations, mainly due to the continuous secretion of saliva (0.5 to 2 L/day), which may lead to dilution, possible ingestion, and unintentional removal of the active drug. Nanotechnology-based drug delivery systems, such as liquid crystalline systems (LCSs), can increase drug permeation through the mucosa and thereby improve drug delivery. This study aimed at developing and characterizing the mechanical, rheological, and mucoadhesive properties of four liquid crystalline precursor systems (LCPSs) composed of four different aqueous phases (i) water (FW), (ii) chitosan (FC), (iii) polyethyleneimine (FP), or (iv) both polymers (FPC); oleic acid was used as the oil phase, and ethoxylated and propoxylated cetyl alcohol was used as the surfactant. Polarized light microscopy and small-angle X-ray scattering indicated that all LCPSs formed liquid crystalline states after incorporation of saliva. Rheological, texture, and mucoadhesive assays showed that FPC had the most suitable characteristics for buccal application. In vitro release study showed that FPC could act as a controlled drug delivery system. Finally, based on in vitro cytotoxicity data, FPC is a safe buccal drug delivery system for the treatment of several buccal diseases.

Host cell processes that influence the intracellular survival of Legionella pneumophila.

PubMed

Shin, Sunny; Roy, Craig R

2008-06-01

Key to the pathogenesis of intracellular pathogens is their ability to manipulate host cell processes, permitting the establishment of an intracellular replicative niche. In turn, the host cell deploys defence mechanisms that limit intracellular infection. The bacterial pathogen Legionella pneumophila, the aetiological agent of Legionnaire's Disease, has evolved virulence mechanisms that allow it to replicate within protozoa, its natural host. Many of these tactics also enable L. pneumophila's survival and replication inside macrophages within a membrane-bound compartment known as the Legionella-containing vacuole. One of the virulence factors indispensable for L. pneumophila's intracellular survival is a type IV secretion system, which translocates a large repertoire of bacterial effectors into the host cell. These effectors modulate multiple host cell processes and in particular, redirect trafficking of the L. pneumophila phagosome and mediate its conversion into an ER-derived organelle competent for intracellular bacterial replication. In this review, we discuss how L. pneumophila manipulates host cells, as well as host cell processes that either facilitate or impede its intracellular survival.

The effects of inhibiting cytochrome P450 3A, p-glycoprotein, and gastric acid secretion on the oral bioavailability of methadone in dogs.

PubMed

Kukanich, B; Lascelles, B D X; Aman, A M; Mealey, K L; Papich, M G

2005-10-01

Methadone is an opioid, which has a high oral bioavailability (>70%) and a long elimination half-life (>20 h) in human beings. The purpose of this study was to evaluate the effects of ketoconazole [a CYP3A and p-glycoprotein (p-gp) inhibitor] and omeprazole (an H+,K(+)-ATPase proton-pump inhibitor) on oral methadone bioavailability in dogs. Six healthy dogs were used in a crossover design. Methadone was administered i.v. (1 mg/kg), orally (2 mg/kg), again orally following oral ketoconazole (10 mg/kg q12 h for two doses), and following omeprazole (1 mg/kg p.o. q12 h for five doses). Plasma concentrations of methadone were analyzed by high-pressure liquid chromatography or fluorescence polarization immunoassay. The mean +/- SD for the elimination half-life, volume of distribution, and clearance were 1.75 +/- 0.25 h, 3.46 +/- 1.09 L/kg, and 25.14 +/- 9.79 mL/min.kg, respectively following i.v. administration. Methadone was not detected in any sample following oral administration alone or following oral administration with omeprazole. Following administration with ketoconazole, detectable concentrations of methadone were present in one dog with a 29% bioavailability. MDR-1 genotyping, encoding p-gp, was normal in all dogs. In contrast to its pharmacokinetics humans, methadone has a short elimination half-life, rapid clearance, and low oral bioavailability in dogs and the extent of absorption is not affected by inhibition of CYP3A, p-gp, and gastric acid secretion.

Hyperglycemia-Induced Modulation of the Physiognomy and Angiogenic Potential of Fibroblasts Mediated by Matrix Metalloproteinase-2: Implications for Venous Stenosis Formation Associated with Hemodialysis Vascular Access in Diabetic Milieu.

PubMed

Janardhanan, Rajiv; Kilari, Sreenivasulu; Leof, Edward B; Misra, Sanjay

2015-01-01

It is hypothesized that venous stenosis formation associated with hemodialysis vascular-access failure is caused by hypoxia-mediated fibroblast-to-myofibroblast differentiation accompanied by proliferation and migration, and that diabetic patients have worse clinical outcomes. The aim of this study was to determine the functional and gene expression outcomes of matrix metalloproteinase-2 (Mmp-2) silencing in fibroblasts cultured under hyperglycemia and euglycemia with hypoxic and normoxic stimuli. AKR-2B fibroblasts were stably transduced using lentivirus-mediated shRNA-Mmp-2 or scrambled controls and subjected to hypoxia or normoxia under hyperglycemic or euglycemic conditions for 24 and 72 h. Gene expression of vascular endothelial growth factor-A (Vegf-A), Vegfr-1, Mmp-2, Mmp-9 and tissue inhibitors of matrix metalloproteinases (Timps) were determined by RT-PCR. Collagen I and IV secretion and cellular proliferation and migration were determined. Under hyperglycemic conditions, there is a significant reduction in the average gene expression of Vegf-A and Mmp-9, with an increase in Timp-1 at 24 h of hypoxia (p < 0.05) in Mmp-2-silenced fibroblasts when compared to controls. In addition, there is a decrease in collagen I and IV secretion and cellular migration. The euglycemic cells were able to reverse these findings. These findings demonstrate the rationale for using anti-Mmp-2 therapy in dialysis patients with hemodialysis vascular access in helping to reduce stenosis formation. © 2016 The Author(s) Published by S. Karger AG, Basel.

A Novel Splice-Site Mutation in Angiotensin I-Converting Enzyme (ACE) Gene, c.3691+1G>A (IVS25+1G>A), Causes a Dramatic Increase in Circulating ACE through Deletion of the Transmembrane Anchor

PubMed Central

Persu, Alexandre; Lambert, Michel; Deinum, Jaap; Cossu, Marta; de Visscher, Nathalie; Irenge, Leonid; Ambroise, Jerôme; Minon, Jean-Marc; Nesterovitch, Andrew B.; Churbanov, Alexander; Popova, Isolda A.; Danilov, Sergei M.; Danser, A. H. Jan; Gala, Jean-Luc

2013-01-01

Background Angiotensin-converting enzyme (ACE) (EC 4.15.1) metabolizes many biologically active peptides and plays a key role in blood pressure regulation and vascular remodeling. Elevated ACE levels are associated with different cardiovascular and respiratory diseases. Methods and Results Two Belgian families with a 8-16-fold increase in blood ACE level were incidentally identified. A novel heterozygous splice site mutation of intron 25 - IVS25+1G>A (c.3691+1G>A) - cosegregating with elevated plasma ACE was identified in both pedigrees. Messenger RNA analysis revealed that the mutation led to the retention of intron 25 and Premature Termination Codon generation. Subjects harboring the mutation were mostly normotensive, had no left ventricular hypertrophy or cardiovascular disease. The levels of renin-angiotensin-aldosterone system components in the mutated cases and wild-type controls were similar, both at baseline and after 50 mg captopril. Compared with non-affected members, quantification of ACE surface expression and shedding using flow cytometry assay of dendritic cells derived from peripheral blood monocytes of affected members, demonstrated a 50% decrease and 3-fold increase, respectively. Together with a dramatic increase in circulating ACE levels, these findings argue in favor of deletion of transmembrane anchor, leading to direct secretion of ACE out of cells. Conclusions We describe a novel mutation of the ACE gene associated with a major familial elevation of circulating ACE, without evidence of activation of the renin-angiotensin system, target organ damage or cardiovascular complications. These data are consistent with the hypothesis that membrane-bound ACE, rather than circulating ACE, is responsible for Angiotensin II generation and its cardiovascular consequences. PMID:23560051

Octreotide exerts different effects in vivo and in vitro in Cushing's disease.

PubMed

Stalla, G K; Brockmeier, S J; Renner, U; Newton, C; Buchfelder, M; Stalla, J; Müller, O A

1994-02-01

The effect of the long-acting somatostatin analog octreotide (SMS 201-995) on adrenocorticotropin (ACTH) secretion was studied in five patients with untreated Cushing's disease in vivo and in six human corticotropic adenoma cell cultures in vitro. For the in vivo study, 100 micrograms of octreotide sc was given 30 and 180 min after cannulation of the cubital vein and 100 micrograms of corticotropin-releasing hormone (CRH) was injected iv at 210 min. Serum ACTH and cortisol levels were measured for 390 min. In vivo, octreotide had no significant effect either on basal or CRH-stimulated ACTH levels and did not influence cortisol levels. The in vitro studies were conducted with corticotropic adenoma cell cultures derived from adenoma tissue obtained from six patients with Cushing's disease. In four of six cell cultures, octreotide (1 nmol/l-1 mumol/l) inhibited basal ACTH secretion in a dose-dependent manner. The inhibition ranged from 70 to 92% for 1 nmol/l octreotide to 14-46% for 1 mumol/l octreotide as compared to controls (100%). In three of three octreotide-responsive adenoma cell cultures investigated. CRH-stimulated ACTH secretion was suppressed by octreotide. Hydrocortisone pretreatment in vitro abolished the inhibitory effect of octreotide on ACTH secretion in one octreotide-responsive corticotropic adenoma cell culture. In conclusion, we showed that octreotide in most cases could inhibit the ACTH release from human corticotropic adenoma cells in vitro but had no suppressive effect on ACTH levels of patients with Cushing's disease in vivo. This discrepancy could be due to a somatostatin receptor down-regulation by cortisol at the hypercortisolemic state in vivo.

Central Nervous System Neuropeptide Y Signaling Modulates VLDL Triglyceride Secretion

PubMed Central

Stafford, John M.; Yu, Fang; Printz, Richard; Hasty, Alyssa H.; Swift, Larry L.; Niswender, Kevin D.

2014-01-01

OBJECTIVE Elevated triglyceride (TG) is the major plasma lipid abnormality in obese and diabetic patients and contributes to cardiovascular morbidity in these disorders. We sought to identify novel mechanisms leading to hypertriglyceridemia. Resistance to negative feedback signals from adipose tissue in key central nervous system (CNS) energy homeostatic circuits contributes to the development of obesity. Because triglycerides both represent the largest energy depot in the body and are elevated in both the plasma and adipose in obesity and diabetes, we hypothesized that the same neural circuits that regulate energy balance also regulate the secretion of TGs into plasma. RESEARCH DESIGN AND METHODS In normal fasting rats, the TG secretion rate was estimated by serial blood sampling after intravascular tyloxapol pretreatment. Neuropeptide Y (NPY) signaling in the CNS was modulated by intracerebroventricular injection of NPY, receptor antagonist, and receptor agonist. RESULTS A single intracerebroventricular injection of NPY increased TG secretion by 2.5-fold in the absence of food intake, and this was determined to be VLDL by fast performance liquid chromatography (FPLC). This effect was recapitulated by activating NPY signaling in downstream neurons with an NPY-Y5 receptor agonist. An NPY-Y1 receptor antagonist decreased the elevated TGs in the form of VLDL secretion rate by 50% compared with vehicle. Increased TG secretion was due to increased secretion of VLDL particles, rather than secretion of larger particles, because apolipoprotein B100 was elevated in FPLC fractions corresponding to VLDL. CONCLUSIONS We find that a key neuropeptide system involved in energy homeostasis in the CNS exerts control over VLDL-TG secretion into the bloodstream. PMID:18332095

The role of intrinsic disorder and dynamics in the assembly and function of the type II secretion system.

PubMed

Gu, Shuang; Shevchik, Vladimir E; Shaw, Rosie; Pickersgill, Richard W; Garnett, James A

2017-10-01

Many Gram-negative commensal and pathogenic bacteria use a type II secretion system (T2SS) to transport proteins out of the cell. These exported proteins or substrates play a major role in toxin delivery, maintaining biofilms, replication in the host and subversion of host immune responses to infection. We review the current structural and functional work on this system and argue that intrinsically disordered regions and protein dynamics are central for assembly, exo-protein recognition, and secretion competence of the T2SS. The central role of intrinsic disorder-order transitions in these processes may be a particular feature of type II secretion. Copyright © 2017 Elsevier B.V. All rights reserved.

A gatekeeper chaperone complex directs translocator secretion during Type Three Secretion

DOE PAGES

Archuleta, Tara L.; Spiller, Benjamin W.; Kubori, Tomoko

2014-11-06

Many Gram-negative bacteria use Type Three Secretion Systems (T3SS) to deliver effector proteins into host cells. These protein delivery machines are composed of cytosolic components that recognize substrates and generate the force needed for translocation, the secretion conduit, formed by a needle complex and associated membrane spanning basal body, and translocators that form the pore in the target cell. A defined order of secretion in which needle component proteins are secreted first, followed by translocators, and finally effectors, is necessary for this system to be effective. While the secreted effectors vary significantly between organisms, the ~20 individual protein components thatmore » form the T3SS are conserved in many pathogenic bacteria. One such conserved protein, referred to as either a plug or gatekeeper, is necessary to prevent unregulated effector release and to allow efficient translocator secretion. The mechanism by which translocator secretion is promoted while effector release is inhibited by gatekeepers is unknown. We present the structure of the Chlamydial gatekeeper, CopN, bound to a translocator-specific chaperone. The structure identifies a previously unknown interface between gatekeepers and translocator chaperones and reveals that in the gatekeeper-chaperone complex the canonical translocator-binding groove is free to bind translocators. Thus, structure-based mutagenesis of the homologous complex in Shigella reveals that the gatekeeper-chaperone-translocator complex is essential for translocator secretion and for the ordered secretion of translocators prior to effectors.« less

Characterization of Nops, nodulation outer proteins, secreted via the type III secretion system of NGR234.

PubMed

Marie, Corinne; Deakin, William J; Viprey, Virginie; Kopciñska, Joanna; Golinowski, Wladyslaw; Krishnan, Hari B; Perret, Xavier; Broughton, William J

2003-09-01

The nitrogen-fixing symbiotic bacterium Rhizobium species NGR234 secretes, via a type III secretion system (TTSS), proteins called Nops (nodulation outer proteins). Abolition of TTSS-dependent protein secretion has either no effect or leads to a change in the number of nodules on selected plants. More dramatically, Nops impair nodule development on Crotalaria juncea roots, resulting in the formation of nonfixing pseudonodules. A double mutation of nopX and nopL, which code for two previously identified secreted proteins, leads to a phenotype on Pachyrhizus tuberosus differing from that of a mutant in which the TTSS is not functional. Use of antibodies and a modification of the purification protocol revealed that NGR234 secretes additional proteins in a TTSS-dependent manner. One of them was identified as NopA, a small 7-kDa protein. Single mutations in nopX and nopL were also generated to assess the involvement of each Nop in protein secretion and nodule formation. Mutation of nopX had little effect on NopL and NopA secretion but greatly affected the interaction of NGR234 with many plant hosts tested. NopL was not necessary for the secretion of any Nops but was required for efficient nodulation of some plant species. NopL may thus act as an effector protein whose recognition is dependent upon the hosts' genetic background.

Secreted bacterial effectors that inhibit host protein synthesis are critical for induction of the innate immune response to virulent Legionella pneumophila.

PubMed

Fontana, Mary F; Banga, Simran; Barry, Kevin C; Shen, Xihui; Tan, Yunhao; Luo, Zhao-Qing; Vance, Russell E

2011-02-01

The intracellular bacterial pathogen Legionella pneumophila causes an inflammatory pneumonia called Legionnaires' Disease. For virulence, L. pneumophila requires a Dot/Icm type IV secretion system that translocates bacterial effectors to the host cytosol. L. pneumophila lacking the Dot/Icm system is recognized by Toll-like receptors (TLRs), leading to a canonical NF-κB-dependent transcriptional response. In addition, L. pneumophila expressing a functional Dot/Icm system potently induces unique transcriptional targets, including proinflammatory genes such as Il23a and Csf2. Here we demonstrate that this Dot/Icm-dependent response, which we term the effector-triggered response (ETR), requires five translocated bacterial effectors that inhibit host protein synthesis. Upon infection of macrophages with virulent L. pneumophila, these five effectors caused a global decrease in host translation, thereby preventing synthesis of IκB, an inhibitor of the NF-κB transcription factor. Thus, macrophages infected with wildtype L. pneumophila exhibited prolonged activation of NF-κB, which was associated with transcription of ETR target genes such as Il23a and Csf2. L. pneumophila mutants lacking the five effectors still activated TLRs and NF-κB, but because the mutants permitted normal IκB synthesis, NF-κB activation was more transient and was not sufficient to fully induce the ETR. L. pneumophila mutants expressing enzymatically inactive effectors were also unable to fully induce the ETR, whereas multiple compounds or bacterial toxins that inhibit host protein synthesis via distinct mechanisms recapitulated the ETR when administered with TLR ligands. Previous studies have demonstrated that the host response to bacterial infection is induced primarily by specific microbial molecules that activate TLRs or cytosolic pattern recognition receptors. Our results add to this model by providing a striking illustration of how the host immune response to a virulent pathogen can also be shaped by pathogen-encoded activities, such as inhibition of host protein synthesis.

Characterization of Shikonin Derivative Secretion in Lithospermum erythrorhizon Hairy Roots as a Model of Lipid-Soluble Metabolite Secretion from Plants

PubMed Central

Tatsumi, Kanade; Yano, Mariko; Kaminade, Kenta; Sugiyama, Akifumi; Sato, Mayuko; Toyooka, Kiminori; Aoyama, Takashi; Sato, Fumihiko; Yazaki, Kazufumi

2016-01-01

Shikonin derivatives are specialized lipophilic metabolites, secreted in abundant amounts from the root epidermal cells of Lithospermum erythrorhizon. Because they have anti-microbial activities, these compounds, which are derivatives of red naphthoquinone, are thought to serve as a chemical barrier for plant roots. The mechanism by which they are secreted from cells is, however, largely unknown. The shikonin production system in L. erythrorhizon is an excellent model for studying the mechanism by which lipophilic compounds are secreted from plant cells, because of the abundant amounts of these compounds produced by L. erythrorhizon, the 0 to 100% inducibility of their production, the light-specific inhibition of production, and the visibility of these products as red pigments. To date, many factors regulating shikonin biosynthesis have been identified, but no mechanism that regulates shikonin secretion without inhibiting biosynthesis has been detected. This study showed that inhibitors of membrane traffic strongly inhibit shikonin secretion without inhibiting shikonin production, suggesting that the secretion of shikonin derivatives into the apoplast utilizes pathways common to the ADP-ribosylation factor/guanine nucleotide exchange factor (ARF/GEF) system and actin filament polymerization, at least in part. These findings provide clues about the machinery involved in secreting lipid-soluble metabolites from cells. PMID:27507975

Characterization of Shikonin Derivative Secretion in Lithospermum erythrorhizon Hairy Roots as a Model of Lipid-Soluble Metabolite Secretion from Plants.

PubMed

Tatsumi, Kanade; Yano, Mariko; Kaminade, Kenta; Sugiyama, Akifumi; Sato, Mayuko; Toyooka, Kiminori; Aoyama, Takashi; Sato, Fumihiko; Yazaki, Kazufumi

2016-01-01

Shikonin derivatives are specialized lipophilic metabolites, secreted in abundant amounts from the root epidermal cells of Lithospermum erythrorhizon. Because they have anti-microbial activities, these compounds, which are derivatives of red naphthoquinone, are thought to serve as a chemical barrier for plant roots. The mechanism by which they are secreted from cells is, however, largely unknown. The shikonin production system in L. erythrorhizon is an excellent model for studying the mechanism by which lipophilic compounds are secreted from plant cells, because of the abundant amounts of these compounds produced by L. erythrorhizon, the 0 to 100% inducibility of their production, the light-specific inhibition of production, and the visibility of these products as red pigments. To date, many factors regulating shikonin biosynthesis have been identified, but no mechanism that regulates shikonin secretion without inhibiting biosynthesis has been detected. This study showed that inhibitors of membrane traffic strongly inhibit shikonin secretion without inhibiting shikonin production, suggesting that the secretion of shikonin derivatives into the apoplast utilizes pathways common to the ADP-ribosylation factor/guanine nucleotide exchange factor (ARF/GEF) system and actin filament polymerization, at least in part. These findings provide clues about the machinery involved in secreting lipid-soluble metabolites from cells.

The importance of connections between the cell wall integrity pathway and the unfolded protein response in filamentous fungi.

PubMed

Malavazi, Iran; Goldman, Gustavo Henrique; Brown, Neil Andrew

2014-11-01

In the external environment, or within a host organism, filamentous fungi experience sudden changes in nutrient availability, osmolality, pH, temperature and the exposure to toxic compounds. The fungal cell wall represents the first line of defense, while also performing essential roles in morphology, development and virulence. A polarized secretion system is paramount for cell wall biosynthesis, filamentous growth, nutrient acquisition and interactions with the environment. The unique ability of filamentous fungi to secrete has resulted in their industrial adoption as fungal cell factories. Protein maturation and secretion commences in the endoplasmic reticulum (ER). The unfolded protein response (UPR) maintains ER functionality during exposure to secretion and cell wall stress. UPR, therefore, influences secretion and cell wall homeostasis, which in turn impacts upon numerous fungal traits important to pathogenesis and biotechnology. Subsequently, this review describes the relevance of the cell wall and UPR systems to filamentous fungal pathogens or industrial microbes and then highlights interconnections between the two systems. Ultimately, the possible biotechnological applications of an enhanced understanding of such regulatory systems in combating fungal disease, or the removal of natural bottlenecks in protein secretion in an industrial setting, are discussed. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

45 CFR 1355.53 - Conditions for approval of funding.

Code of Federal Regulations, 2010 CFR

2010-10-01

... title IV-A, (ii) National Child Abuse and Neglect Data Systems (NCANDS), (iii) Systems operated under title XIX, and (iv) Systems operated under title IV-D; (3) Support the provisions of section 422(a) by... system, which is effective and efficient, to improve the program management and administration of the...

Circulating anti-double-stranded DNA antibody-secreting cells in patients with systemic lupus erythematosus: a novel biomarker for disease activity.

PubMed

Hanaoka, H; Okazaki, Y; Satoh, T; Kaneko, Y; Yasuoka, H; Seta, N; Kuwana, M

2012-10-01

Antibodies against double-stranded DNA (dsDNA) are widely used to diagnose systemic lupus erythematosus (SLE) and evaluate its activity in patients. This study was undertaken to examine the clinical utility of circulating anti-dsDNA antibody-secreting cells for evaluating SLE patients. Anti-dsDNA antibody-secreting cells quantified using an enzyme-linked immunospot assay were detected in the spleen, bone marrow and peripheral blood from MRL/lpr but not in control BALB/c mice. Circulating anti-dsDNA antibody-secreting cells were detected in 29 (22%) of 130 patients with SLE, but in none of 49 with non-SLE connective-tissue disease or 18 healthy controls. The presence of circulating anti-dsDNA antibody-secreting cells was associated with persistent proteinuria, high SLE disease activity index and systemic lupus activity measures, and a high serum anti-dsDNA antibody titre measured with an enzyme-linked immunosorbent assay. The positive predictive value for active disease was 48% for circulating anti-dsDNA antibody-secreting cells versus 17% for serum anti-dsDNA antibodies. A prospective cohort of patients with circulating anti-dsDNA antibodies and inactive SLE showed that the cumulative disease flare-free rate was significantly lower in patients with than without circulating anti-dsDNA antibody-secreting cells (p < 0.001). Circulating anti-dsDNA antibody-secreting cells are a useful biomarker for assessing disease activity in SLE patients.

Two-Party secret key distribution via a modified quantum secret sharing protocol

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

Grice, Warren P.; Evans, Philip G.; Lawrie, Benjamin

We present and demonstrate a method of distributing secret information based on N-party single-qubit Quantum Secret Sharing (QSS) in a modied plug-and-play two-party Quantum Key Distribution (QKD) system with N 2 intermediate nodes and compare it to both standard QSS and QKD. Our setup is based on the Clavis2 QKD system built by ID Quantique but is generalizable to any implementation. We show that any two out of N parties can build a secret key based on partial information from each other and with collaboration from the remaining N 2 parties. This method signicantly reduces the number of resources (singlemore » photon detectors, lasers and dark ber connections) needed to implement QKD on the grid.« less

Two-Party secret key distribution via a modified quantum secret sharing protocol

DOE PAGES

Grice, Warren P.; Evans, Philip G.; Lawrie, Benjamin; ...

2015-01-01

We present and demonstrate a method of distributing secret information based on N-party single-qubit Quantum Secret Sharing (QSS) in a modied plug-and-play two-party Quantum Key Distribution (QKD) system with N 2 intermediate nodes and compare it to both standard QSS and QKD. Our setup is based on the Clavis2 QKD system built by ID Quantique but is generalizable to any implementation. We show that any two out of N parties can build a secret key based on partial information from each other and with collaboration from the remaining N 2 parties. This method signicantly reduces the number of resources (singlemore » photon detectors, lasers and dark ber connections) needed to implement QKD on the grid.« less

The Role of Pathogen-Secreted Proteins in Fungal Vascular Wilt Diseases

PubMed Central

de Sain, Mara; Rep, Martijn

2015-01-01

A limited number of fungi can cause wilting disease in plants through colonization of the vascular system, the most well-known being Verticillium dahliae and Fusarium oxysporum. Like all pathogenic microorganisms, vascular wilt fungi secrete proteins during host colonization. Whole-genome sequencing and proteomics screens have identified many of these proteins, including small, usually cysteine-rich proteins, necrosis-inducing proteins and enzymes. Gene deletion experiments have provided evidence that some of these proteins are required for pathogenicity, while the role of other secreted proteins remains enigmatic. On the other hand, the plant immune system can recognize some secreted proteins or their actions, resulting in disease resistance. We give an overview of proteins currently known to be secreted by vascular wilt fungi and discuss their role in pathogenicity and plant immunity. PMID:26473835

A 2,4-dichlorophenoxyacetic acid degradation plasmid pM7012 discloses distribution of an unclassified megaplasmid group across bacterial species.

PubMed

Sakai, Yoriko; Ogawa, Naoto; Shimomura, Yumi; Fujii, Takeshi

2014-03-01

Analysis of the complete nucleotide sequence of plasmid pM7012 from 2,4-dichlorophenoxyacetic-acid (2,4-D)-degrading bacterium Burkholderia sp. M701 revealed that the plasmid had 582 142 bp, with 541 putative protein-coding sequences and 39 putative tRNA genes for the transport of the standard 20 aa. pM7012 contains sequences homologous to the regions involved in conjugal transfer and plasmid maintenance found in plasmids byi_2p from Burkholderia sp. YI23 and pBVIE01 from Burkholderia sp. G4. No relaxase gene was found in any of these plasmids, although genes for a type IV secretion system and type IV coupling proteins were identified. Plasmids with no relaxase gene have been classified as non-mobile plasmids. However, nucleotide sequences with a high level of similarity to the genes for plasmid transfer, plasmid maintenance, 2,4-D degradation and arsenic resistance contained on pM7012 were also detected in eight other megaplasmids (~600 or 900 kb) found in seven Burkholderia strains and a strain of Cupriavidus, which were isolated as 2,4-D-degrading bacteria in Japan and the United States. These results suggested that the 2,4-D degradation megaplasmids related to pM7012 are mobile and distributed across various bacterial species worldwide, and that the plasmid group could be distinguished from known mobile plasmid groups.

Stromal Cells Positively and Negatively Modulate the Growth of Cancer Cells: Stimulation via the PGE2-TNFα-IL-6 Pathway and Inhibition via Secreted GAPDH-E-Cadherin Interaction

PubMed Central

Kawada, Manabu; Inoue, Hiroyuki; Ohba, Shun-ichi; Yoshida, Junjiro; Masuda, Tohru; Yamasaki, Manabu; Usami, Ihomi; Sakamoto, Shuichi; Abe, Hikaru; Watanabe, Takumi; Yamori, Takao; Shibasaki, Masakatsu; Nomoto, Akio

2015-01-01

Fibroblast-like stromal cells modulate cancer cells through secreted factors and adhesion, but those factors are not fully understood. Here, we have identified critical stromal factors that modulate cancer growth positively and negatively. Using a cell co-culture system, we found that gastric stromal cells secreted IL-6 as a growth and survival factor for gastric cancer cells. Moreover, gastric cancer cells secreted PGE2 and TNFα that stimulated IL-6 secretion by the stromal cells. Furthermore, we found that stromal cells secreted glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Extracellular GAPDH, or its N-terminal domain, inhibited gastric cancer cell growth, a finding confirmed in other cell systems. GAPDH bound to E-cadherin and downregulated the mTOR-p70S6 kinase pathway. These results demonstrate that stromal cells could regulate cancer cell growth through the balance of these secreted factors. We propose that negative regulation of cancer growth using GAPDH could be a new anti-cancer strategy. PMID:25785838

Structure of Salmonella FlhE, conserved member of a flagellar Type III secretion operon

DOE PAGES

Lee, Jaemin; Monzingo, Arthur F.; Keatinge-Clay, Adrian T.; ...

2014-12-26

In this paper, the bacterial flagellum is assembled by a multicomponent transport apparatus categorized as a type III secretion system. The secretion of proteins that assemble into the flagellum is driven by the proton motive force. The periplasmic protein FlhE is a member of the flhBAE operon in the majority of bacteria where FlhE is found. FlhA and FlhB are established components of the flagellar type III secretion system. The absence of FlhE results in a proton leak through the flagellar system, inappropriate secretion patterns, and cell death, indicating that FlhE regulates an important aspect of proper flagellar biosynthesis. Wemore » isolated FlhE from the periplasm of Salmonella and solved its structure to 1.5 Å resolution. The structure reveals a β-sandwich fold, with no close structural homologs. Finally, possible roles of FlhE, including that of a chaperone, are discussed.« less

Structure of Salmonella FlhE, conserved member of a flagellar Type III secretion operon

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

Lee, Jaemin; Monzingo, Arthur F.; Keatinge-Clay, Adrian T.

In this paper, the bacterial flagellum is assembled by a multicomponent transport apparatus categorized as a type III secretion system. The secretion of proteins that assemble into the flagellum is driven by the proton motive force. The periplasmic protein FlhE is a member of the flhBAE operon in the majority of bacteria where FlhE is found. FlhA and FlhB are established components of the flagellar type III secretion system. The absence of FlhE results in a proton leak through the flagellar system, inappropriate secretion patterns, and cell death, indicating that FlhE regulates an important aspect of proper flagellar biosynthesis. Wemore » isolated FlhE from the periplasm of Salmonella and solved its structure to 1.5 Å resolution. The structure reveals a β-sandwich fold, with no close structural homologs. Finally, possible roles of FlhE, including that of a chaperone, are discussed.« less

Inhibition of a type III secretion system by the deletion of a short loop in one of its membrane proteins

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

Meshcheryakov, Vladimir A.; Kitao, Akio; Core Research for Evolutionary Science and Technology, Tokyo 113-0032

2013-05-01

Crystal structures of the cytoplasmic domain of FlhB from S. typhimurium and A. aeolicus were solved at 2.45 and 2.55 Å resolution, respectively. The deletion of a short loop in the cytoplasmic domain of Salmonella FlhB completely abolishes secretion by the type III secretion system. A molecular-dynamics simulation shows that the deletion of the loop affects the flexibility of a linker between the transmembrane and cytoplasmic domains of FlhB. The membrane protein FlhB is a highly conserved component of the flagellar secretion system. It is composed of an N-terminal transmembrane domain and a C-terminal cytoplasmic domain (FlhB{sub C}). Here, themore » crystal structures of FlhB{sub C} from Salmonella typhimurium and Aquifex aeolicus are described at 2.45 and 2.55 Å resolution, respectively. These flagellar FlhB{sub C} structures are similar to those of paralogues from the needle type III secretion system, with the major difference being in a linker that connects the transmembrane and cytoplasmic domains of FlhB. It was found that deletion of a short flexible loop in a globular part of Salmonella FlhB{sub C} leads to complete inhibition of secretion by the flagellar secretion system. Molecular-dynamics calculations demonstrate that the linker region is the most flexible part of FlhB{sub C} and that the deletion of the loop reduces this flexibility. These results are in good agreement with previous studies showing the importance of the linker in the function of FlhB and provide new insight into the relationship between the different parts of the FlhB{sub C} molecule.« less

The PCP SYS IV Management System: Educational Overview.

ERIC Educational Resources Information Center

Siegel, Martin A.; Davis, Dennis M.

This paper describes the structure and function of the SYS IV PLATO Curriculum Project's (PCP) computer-based management system and justifies the system design. A consideration of features most critical in the design of management systems provides the context for a discussion of specific SYS IV features, which include its ability to deliver any…

Regulation of pulmonary surfactant secretion in the developing lizard, Pogona vitticeps.

PubMed

Sullivan, Lucy C; Orgeig, Sandra; Daniels, Christopher B

2002-11-01

Pulmonary surfactant is a mixture of lipids and proteins that is secreted by alveolar type II cells in the lungs of all air-breathing vertebrates. Pulmonary surfactant functions to reduce the surface tension in the lungs and, therefore, reduce the work of breathing. In mammals, the embryonic maturation of the surfactant system is controlled by a host of factors, including glucocorticoids, thyroid hormones and autonomic neurotransmitters. We have used a co-culture system of embryonic type II cells and lung fibroblasts to investigate the ability of dexamethasone, tri-iodothyronine (T(3)), adrenaline and carbamylcholine (carbachol) to stimulate the cellular secretion of phosphatidylcholine in the bearded dragon (Pogona vitticeps) at day 55 (approx. 92%) of incubation and following hatching. Adrenaline stimulated surfactant secretion both before and after hatching, whereas carbachol stimulated secretion only at day 55. Glucocorticoids and triiodothyronine together stimulated secretion at day 55 but did not after hatching. Therefore, adrenaline, carbachol, dexamethasone and T(3), are all involved in the development of the surfactant system in the bearded dragon. However, the efficacy of the hormones is attenuated during the developmental process. These differences probably relate to the changes in the cellular environment during development and the specific biology of the bearded dragon.

A FRET-Based DNA Biosensor Tracks OmpR-Dependent Acidification of Salmonella during Macrophage Infection

PubMed Central

Chakraborty, Smarajit; Mizusaki, Hideaki; Kenney, Linda J.

2015-01-01

In bacteria, one paradigm for signal transduction is the two-component regulatory system, consisting of a sensor kinase (usually a membrane protein) and a response regulator (usually a DNA binding protein). The EnvZ/OmpR two-component system responds to osmotic stress and regulates expression of outer membrane proteins. In Salmonella, EnvZ/OmpR also controls expression of another two-component system SsrA/B, which is located on Salmonella Pathogenicity Island (SPI) 2. SPI-2 encodes a type III secretion system, which functions as a nanomachine to inject bacterial effector proteins into eukaryotic cells. During the intracellular phase of infection, Salmonella switches from assembling type III secretion system structural components to secreting effectors into the macrophage cytoplasm, enabling Salmonella to replicate in the phagocytic vacuole. Major questions remain regarding how bacteria survive the acidified vacuole and how acidification affects bacterial secretion. We previously reported that EnvZ sensed cytoplasmic signals rather than extracellular ones, as intracellular osmolytes altered the dynamics of a 17-amino-acid region flanking the phosphorylated histidine. We reasoned that the Salmonella cytoplasm might acidify in the macrophage vacuole to activate OmpR-dependent transcription of SPI-2 genes. To address these questions, we employed a DNA-based FRET biosensor (“I-switch”) to measure bacterial cytoplasmic pH and immunofluorescence to monitor effector secretion during infection. Surprisingly, we observed a rapid drop in bacterial cytoplasmic pH upon phagocytosis that was not predicted by current models. Cytoplasmic acidification was completely dependent on the OmpR response regulator, but did not require known OmpR-regulated genes such as ompC, ompF, or ssaC (SPI-2). Microarray analysis highlighted the cadC/BA operon, and additional experiments confirmed that it was repressed by OmpR. Acidification was blocked in the ompR null background in a Cad-dependent manner. Acid-dependent activation of OmpR stimulated type III secretion; blocking acidification resulted in a neutralized cytoplasm that was defective for SPI-2 secretion. Based upon these findings, we propose that Salmonella infection involves an acid-dependent secretion process in which the translocon SseB moves away from the bacterial cell surface as it associates with the vacuolar membrane, driving the secretion of SPI-2 effectors such as SseJ. New steps in the SPI-2 secretion process are proposed. PMID:25875623

Correlating levels of type III secretion and secreted proteins with fecal shedding of Escherichia coli O157:H7 in cattle

USDA-ARS?s Scientific Manuscript database

The locus of enterocyte effacement (LEE) encodes a type III secretion system (T3SS) for secreting factors that enable Escherichia coli O157:H7 to produce attaching and effacing lesions (A/E) on epithelial cells. The importance of LEE-encoded proteins in intestinal colonization of cattle is well-stud...

Protein Export According to Schedule: Architecture, Assembly, and Regulation of Type III Secretion Systems from Plant- and Animal-Pathogenic Bacteria

PubMed Central

2012-01-01

Summary: Flagellar and translocation-associated type III secretion (T3S) systems are present in most Gram-negative plant- and animal-pathogenic bacteria and are often essential for bacterial motility or pathogenicity. The architectures of the complex membrane-spanning secretion apparatuses of both systems are similar, but they are associated with different extracellular appendages, including the flagellar hook and filament or the needle/pilus structures of translocation-associated T3S systems. The needle/pilus is connected to a bacterial translocon that is inserted into the host plasma membrane and mediates the transkingdom transport of bacterial effector proteins into eukaryotic cells. During the last 3 to 5 years, significant progress has been made in the characterization of membrane-associated core components and extracellular structures of T3S systems. Furthermore, transcriptional and posttranscriptional regulators that control T3S gene expression and substrate specificity have been described. Given the architecture of the T3S system, it is assumed that extracellular components of the secretion apparatus are secreted prior to effector proteins, suggesting that there is a hierarchy in T3S. The aim of this review is to summarize our current knowledge of T3S system components and associated control proteins from both plant- and animal-pathogenic bacteria. PMID:22688814

Functional classification of mitochondrion-rich cells in euryhaline Mozambique tilapia (Oreochromis mossambicus) embryos, by means of triple immunofluorescence staining for Na+/K+-ATPase, Na +/K+/2Cl- cotransporter and CFTR anion channel

USGS Publications Warehouse

Hiroi, J.; McCormick, S.D.; Ohtani-Kaneko, R.; Kaneko, T.

2005-01-01

Mozambique tilapia Oreochromis mossambicus embryos were transferred from freshwater to seawater and vice versa, and short-term changes in the localization of three major ion transport proteins, Na+/K +-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) were examined within mitochondrion-rich cells (MRCs) in the embryonic yolk-sac membrane. Triple-color immunofluorescence staining allowed us to classify MRCs into four types: type I, showing only basolateral Na+/K +-ATPase staining; type II, basolateral Na+/K +-ATPase and apical NKCC; type III, basolateral Na+/K +-ATPase and basolateral NKCC; type IV, basolateral Na +/K+-ATPase, basolateral NKCC and apical CFTR. In freshwater, type-I, type-II and type-III cells were observed. Following transfer from freshwater to seawater, type-IV cells appeared at 12 h and showed a remarkable increase in number between 24 h and 48 h, whereas type-III cells disappeared. When transferred from seawater back to freshwater, type-IV cells decreased and disappeared at 48 h, type-III cells increased, and type-II cells, which were not found in seawater, appeared at 12 h and increased in number thereafter. Type-I cells existed consistently irrespective of salinity changes. These results suggest that type I is an immature MRC, type II is a freshwater-type ion absorptive cell, type III is a dormant type-IV cell and/or an ion absorptive cell (with a different mechanism from type II), and type IV is a seawater-type ion secretory cell. The intracellular localization of the three ion transport proteins in type-IV cells is completely consistent with a widely accepted model for ion secretion by MRCs. A new model for ion absorption is proposed based on type-II cells possessing apical NKCC.

A Polyphenol-Enriched Fraction of Rose Oil Distillation Wastewater Inhibits Cell Proliferation, Migration and TNF-α-Induced VEGF Secretion in Human Immortalized Keratinocytes.

PubMed

Wedler, Jonas; Rusanov, Krasimir; Atanassov, Ivan; Butterweck, Veronika

2016-07-01

Water steam distillation of rose flowers separates the essential oil from the polyphenol-containing rose oil distillation wastewater. Recently, a strategy was developed to separate rose oil distillation wastewater into a polyphenol depleted water fraction and a polyphenol-enriched fraction [RF20-(SP-207)]. The objective of the present study was to investigate RF20-(SP-207) and fraction F(IV), augmented in quercetin and ellagic acid, for possible antiproliferative effects in immortalized human keratinocytes (HaCaT) since rose petals are known to contain compounds with potential antiproliferative activity.RF20-(SP-207) revealed dose-dependent antiproliferative activity (IC50 of 9.78 µg/mL). In a nontoxic concentration of 10 µg/mL, this effect was stronger than that of the two positive controls LY294002 (10 µM, PI3 K-inhibitor, 30 % inhibition) and NVP-BEZ235 (100 nM, dual PI3 K/mTOR inhibitor, 30 % inhibition) and clearly exceeded the antiproliferative action of quercetin (50 µM, 25 % inhibition) and ellagic acid (1 µM, 15 % inhibition). Time-lapse microscopy detected a significant impairment of cell migration of RF20-(SP-207) and F(IV). At concentrations of 10 µg/mL of both, extract and fraction, cell migration was strongly suppressed (51 % and 28 % gap closure, respectively, compared to 95 % gap closure 24 hours after control treatment). The suppression of cell migration was comparable to the positive controls LY294002, NVP-BEZ235, and quercetin. Furthermore, basal and TNF-α-stimulated VEGF-secretion was significantly reduced by RF20-(SP-207) and F(IV) at 10 µg/mL (44 % vs. untreated control).In conclusion, RF20-(SP-207) showed promising antiproliferative and antimigratory effects and could be developed as a supportive, therapy against hyperproliferation-involved skin diseases. Georg Thieme Verlag KG Stuttgart · New York.

Efficient Secretion of Recombinant Proteins from Rice Suspension-Cultured Cells Modulated by the Choice of Signal Peptide.

PubMed

Huang, Li-Fen; Tan, Chia-Chun; Yeh, Ju-Fang; Liu, Hsin-Yi; Liu, Yu-Kuo; Ho, Shin-Lon; Lu, Chung-An

2015-01-01

Plant-based expression systems have emerged as a competitive platform in the large-scale production of recombinant proteins. By adding a signal peptide, αAmy3sp, the desired recombinant proteins can be secreted outside transgenic rice cells, making them easy to harvest. In this work, to improve the secretion efficiency of recombinant proteins in rice expression systems, various signal peptides including αAmy3sp, CIN1sp, and 33KDsp have been fused to the N-terminus of green fluorescent protein (GFP) and introduced into rice cells to explore the efficiency of secretion of foreign proteins. 33KDsp had better efficiency than αAmy3sp and CIN1sp for the secretion of GFP from calli and suspension-cultured cells. 33KDsp was further applied for the secretion of mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF) from transgenic rice suspension-cultured cells; approximately 76%-92% of total rice-derived mGM-CSF (rmGM-CSF) was detected in the culture medium. The rmGM-CSF was bioactive and could stimulate the proliferation of a murine myeloblastic leukemia cell line, NSF-60. The extracellular yield of rmGM-CSF reached 31.7 mg/L. Our study indicates that 33KDsp is better at promoting the secretion of recombinant proteins in rice suspension-cultured cell systems than the commonly used αAmy3sp.

Carbachol improves the secretion of transplanted submandibular glands during the latent period after microvascular autologous transplantation for severe keratoconjunctivitis sicca.

PubMed

Liu, X-J; Li, M; Su, J-Z; Wang, Z; Xie, Z; Yu, G-Y

2016-10-01

Poor secretion of transplanted submandibular glands (SMGs) during the latent period may cause duct obstruction and affects the surgical outcome. The objective of this study was to investigate the efficacy and systemic side effects of carbachol on transplanted SMG secretion. Twenty-seven patients who underwent SMG transplantation for severe keratoconjunctivitis sicca were treated with subcutaneous injections of 0.2mg/2ml carbachol at 10 days, 1 month, and/or 3 months after surgery. The effect on secretion was evaluated by Schirmer test and technetium 99m ((99m)Tc) scintigraphy. Systemic side effects were evaluated subjectively using a questionnaire. The results showed that the time to onset varied from 4 to 9min and the duration of action from 50 to 110min after carbachol administration. The secretion at each time point after drug administration was significantly higher than the pre-administration value (all P<0.01). (99m)Tc scintigraphy showed a decline in the dynamic time-activity curve in 26 patients, demonstrating a stimulatory effect on the secretion of carbachol. No serious systemic side effects were experienced. In conclusion, the intermittent administration of carbachol could be an effective and safe strategy to promote secretion from transplanted SMGs in the latent period to prevent duct obstruction. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Potential immunotoxic effects of trichloroethylene-induced IV allergic reaction in renal impairment

PubMed Central

Yu, Jun-Feng; Feng, Yan-Yan

2017-01-01

Trichloroethylene (TCE) is known to induce allergic contact dermatitis and subsequent occupational medicamentosa-like dermatitis (OMLD) with multi-system injuries, including liver, kidney, and skin injuries. However, the mechanisms underlying immune system dysfunction that result in organ injury have not yet been clearly elucidated. In the present study, we measured the levels of secreted cytokines by effect or T cells in TCE-treated guinea pigs to better understand the contribution of allergic disorders in renal injuries. We immunized guinea pigs with trichloroethylene using the Guinea Pig Maximization Test (GPMT) and scored the inflammation on the guinea pigs’ skin. The kidney function and ultra-structural changes in the kidneys were detected using biochemical methods and electron microscopy. The deposition of cytokines was determined using immunohistochemistry. The sensitization rate was 63.16% in the TCE-sensitized groups. The electron microscopy results showed tubular epithelial cell mitochondrial swelling, vacuolar degeneration, and atrophy of the microvillus in the sensitized groups. A high degree of cytokine deposition was observed in the renal tubular proximal epithelial cells in the TCE-sensitized groups. As observed in this study, the variation in the level of immune system activation not only indicates that TCE can largely magnify the immune reaction but also suggests a potential role of immune dysfunction in renal impairment. PMID:28867961

Clinical use of closed-system safety peripheral intravenous cannulas.

PubMed

Barton, Andrew

2018-04-26

Peripheral intravenous (IV) cannulas are the quickest and most effective way of gaining venous vascular access and administering IV therapy. Closed-system peripheral IV cannulas have been shown to be safe and more reliable than open, non-valved peripheral cannulas in clinical practice. This article introduces the Smiths Medical DeltaVen closed-system peripheral IV cannula and includes three case studies describing its use in clinical practice and associated patient outcomes.

Effect of L-Tryptophan and L-Leucine on Gut Hormone Secretion, Appetite Feelings and Gastric Emptying Rates in Lean and Non-Diabetic Obese Participants: A Randomized, Double-Blind, Parallel-Group Trial

PubMed Central

Meyer-Gerspach, Anne Christin; Häfliger, Simon; Meili, Julian; Doody, Alison; Rehfeld, Jens F; Drewe, Jürgen; Beglinger, Christoph; Wölnerhanssen, Bettina

2016-01-01

Background/Objectives Gut hormones such as cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) play a role as satiation factors. Strategies to enhance satiation peptide secretion could provide a therapeutic approach for obesity. Carbohydrates and lipids have been extensively investigated in relation to peptide release. In contrast, the role of proteins or amino acids is less clear. Our aim was to compare the effects of the amino acids L-tryptophan (L-trp) and L-leucine (L-leu) separately on gastric emptying and gut peptide secretion. Participants/Methods The study was conducted as a randomized (balanced), double-blind, parallel-group trial. A total of 10 lean and 10 non-diabetic obese participants were included. Participants received intragastric loads of L-trp (0.52 g and 1.56 g) and L-leu (1.56 g), dissolved in 300 mL tap water; 75 g glucose and 300 mL tap water served as control treatments. Results Results of the study are: i) L-trp at the higher dose stimulates CCK release (p = 0.0018), and induces a significant retardation in gastric emptying (p = 0.0033); ii) L-trp at the higher dose induced a small increase in GLP-1 secretion (p = 0.0257); iii) neither of the amino acids modulated subjective appetite feelings; and iv) the two amino acids did not alter insulin or glucose concentrations. Conclusions L-trp is a luminal regulator of CCK release with effects on gastric emptying, an effect that could be mediated by CCK. L-trp’s effect on GLP-1 secretion is only minor. At the doses given, the two amino acids did not affect subjective appetite feelings. Trial Registration ClinicalTrials.gov NCT02563847 PMID:27875537

The −258 A/G (SNP rs12885300) polymorphism of the human type-2 deiodinase gene is associated with a shift in the pattern of secretion of thyroid hormones following a TRH-induced acute rise in TSH

PubMed Central

Peltsverger, Maya Y.; Butler, Peter W.; Alberobello, Anna Teresa; Smith, Sheila; Guevara, Yanina; Dubaz, Ornella M.; Luzon, Javier A.; Linderman, Joyce; Celi, Francesco S.

2012-01-01

Objective Type-2 deiodinase gene (DIO2) polymorphisms have been associated with changes in pituitary-thyroid axis homeostasis. The −258 A/G (SNP rs12885300) polymorphism has been associated with increased enzymatic activity, but data are conflicting. To characterize the effects of the −258 A/G polymorphism on intra-thyroidal T4 to T3 conversion and thyroid hormone secretion pattern we studied the effects of acute, TRH-mediated, TSH stimulation of the thyroid gland. Design Retrospective analysis. Methods The thyroid hormone secretion in response to 500 mcg iv TRH injection was studied in 45 healthy volunteers. Results Twenty-six subjects (16 females, 10 males, 32.8±10.4 years) were homozygous for the ancestral (−258 A/A) allele, 19 (11 females, 8 males, 31.1±10.9 years) were carrier of the (−258 G/x) variant. While no differences in the peak TSH and T3 levels were observed, carriers of the −258G/x allele showed a blunted rise in free T4 (p<0.01). The −258G/x 92Thr/Thr haplotype, compared to the other groups, had lower TSH values at 60' (p<0.03). No differences were observed between genotypes in baseline thyroid hormone levels. Conclusions The −258G/x DIO2 polymorphism variant is associated with a decreased rate of acute TSH-stimulated free T4 secretion with a normal T3 release from the thyroid consistent with a shift in the reaction equilibrium toward the product. These data indicate that the −258G DIO2 polymorphism cause changes in the pattern of hormonal secretion. These findings are a proof-of-concept that common polymorphisms in the DIO2 can subtly affect the circulating levels of thyroid hormone and might modulate the thyroid hormone homeostasis. PMID:22307573

Postprandial oxytocin secretion is associated with severity of anxiety and depressive symptoms in anorexia nervosa.

PubMed

Lawson, Elizabeth A; Holsen, Laura M; Santin, McKale; DeSanti, Rebecca; Meenaghan, Erinne; Eddy, Kamryn T; Herzog, David B; Goldstein, Jill M; Klibanski, Anne

2013-05-01

Anorexia nervosa, a psychiatric disorder characterized by self-induced starvation, is associated with endocrine dysfunction and comorbid anxiety and depression. Animal data suggest that oxytocin may have anxiolytic and antidepressant effects. We have reported increased postprandial oxytocin levels in women with active anorexia nervosa and decreased levels in weight-recovered women with anorexia nervosa compared to healthy controls. A meal may represent a significant source of stress in patients with disordered eating. We therefore investigated the association between postprandial oxytocin secretion and symptoms of anxiety and depression in anorexia nervosa. We performed a cross-sectional study of 35 women (13 women with active anorexia nervosa, 9 with weight-recovered anorexia nervosa, and 13 healthy controls). Anorexia nervosa was diagnosed according to DSM-IV-TR criteria. Serum oxytocin and cortisol and plasma leptin levels were measured fasting and 30, 60, and 120 minutes after a standardized mixed meal. The area under the curve (AUC) and, for oxytocin, postprandial nadir and peak levels were determined. Anxiety and depressive symptoms were assessed using the Spielberger State-Trait Anxiety Inventory (STAI) and Beck Depression Inventory II (BDI-II). The study was conducted from January 2009 to March 2011. In women with anorexia nervosa, oxytocin AUC and postprandial nadir and peak levels were positively associated with STAI trait and STAI premeal and postmeal state scores. Oxytocin AUC and nadir levels were positively associated with BDI-II scores. After controlling for cortisol AUC, all of the relationships remained significant. After controlling for leptin AUC, most of the relationships remained significant. Oxytocin secretion explained up to 51% of the variance in STAI trait and 24% of the variance in BDI-II scores. Abnormal postprandial oxytocin secretion in women with anorexia nervosa is associated with increased symptoms of anxiety and depression. This link may represent an adaptive response of oxytocin secretion to food-related symptoms of anxiety and depression. © Copyright 2013 Physicians Postgraduate Press, Inc.

Method for adding nodes to a quantum key distribution system

DOEpatents

Grice, Warren P

2015-02-24

An improved quantum key distribution (QKD) system and method are provided. The system and method introduce new clients at intermediate points along a quantum channel, where any two clients can establish a secret key without the need for a secret meeting between the clients. The new clients perform operations on photons as they pass through nodes in the quantum channel, and participate in a non-secret protocol that is amended to include the new clients. The system and method significantly increase the number of clients that can be supported by a conventional QKD system, with only a modest increase in cost. The system and method are compatible with a variety of QKD schemes, including polarization, time-bin, continuous variable and entanglement QKD.

18 CFR 3a.91 - Data index system.

Code of Federal Regulations, 2011 CFR

2011-04-01

.... A data index system shall be established for Top Secret, Secret, and Confidential information in selected categories prescribed by the Interagency Classification Review Committee, in accordance with section VII of the National Security Council Directive Governing the Classification, Downgrading...

Identification of the Vibrio parahaemolyticus type III secretion system 2-associated chaperone VocC for the T3SS2-specific effector VopC.

PubMed

Akeda, Yukihiro; Kodama, Toshio; Saito, Kazunobu; Iida, Tetsuya; Oishi, Kazunori; Honda, Takeshi

2011-11-01

The enteropathogen Vibrio parahaemolyticus possesses two sets of type III secretion systems, T3SS1 and T3SS2. Effector proteins secreted by these T3SSs are delivered into host cells, leading to cell death or diarrhea. However, it is not known how specific effectors are secreted through a specific T3SS when both T3SSs are expressed within bacteria. One molecule thought to determine secretion specificity is a T3SS-associated chaperone; however, no T3SS2-specific chaperone has been identified. Therefore, we screened T3SS2 chaperone candidates by a pull-down assay using T3SS2 effectors fused with glutathione-S-transferase. A secretion assay revealed that the newly identified cognate chaperone VocC for the T3SS2-specific effector VopC was required for the efficient secretion of the substrate through T3SS2. Further experiments determined the chaperone-binding domain and the amino-terminal secretion signal of the cognate effector. These findings, in addition to the previously identified T3SS1-specific chaperone, VecA, provide a strategy to clarify the specificity of effector secretion through T3SSs of V. parahaemolyticus. 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

DsbA Plays a Critical and Multifaceted Role in the Production of Secreted Virulence Factors by the Phytopathogen Erwinia carotovora subsp. atroseptica*S⃞

PubMed Central

Coulthurst, Sarah J.; Lilley, Kathryn S.; Hedley, Peter E.; Liu, Hui; Toth, Ian K.; Salmond, George P. C.

2008-01-01

Erwinia carotovora subsp. atroseptica is an enterobacterial phytopathogen causing economically significant soft rot disease. Pathogenesis is mediated by multiple secreted virulence factors, many of which are secreted by the type II (Out) secretion system. DsbA catalyzes the introduction of disulfide bonds into periplasmic and secreted proteins. In this study, the extracellular proteome (secretome) of wild type E. carotovora subsp. atroseptica SCRI1043, and dsbA and out mutants, was analyzed by spectral counting mass spectrometry. This revealed that dsbA inactivation had a huge impact on the secretome and identified diverse DsbA- and Out-dependent secreted proteins, representing known, predicted, and novel candidate virulence factors. Further characterization of the dsbA mutant showed that secreted enzyme activities, motility, production of the quorumsensing signal, and virulence were absent or substantially reduced. The impact of DsbA on secreted virulence factor production was mediated at multiple levels, including impacting on the Out secretion system and the virulence gene regulatory network. Transcriptome analyses revealed that the abundance of a broad, but defined, set of transcripts, including many virulence factors, was altered in the dsbA mutant, identifying a new virulence regulon responsive to extracytoplasmic conditions. In conclusion, DsbA plays a crucial, multifaceted role in the pathogenesis of E. carotovora subsp. atroseptica. PMID:18562317

[Exo- and endosecretive digestive glands of enzymes as modulators of secretion].

PubMed

Korot'ko, G F

2010-01-01

Enzymes, exosecreted by the digestive glands plays not only a role of the hydrolases, but also an informational and modulating role in the urgent adaptation of the enzyme secretion to the structure and properties of the luminal content of the gastrointestinal tract. Endosecreted enzymes in the blood not only inform about enzymatic condition of the hydrolase-producing glands and duct system, but also plays an informational and modulating role by the inhibition of the secretion of the same enzymes, and by the stimulation of the secretion of the heteronymic enzyme, defines a parity of their secretion and recretion, integrates enzyme secretion of the pancreas and gastric glands.

Identification and characterization of a type III secretion-associated chaperone in the type III secretion system 1 of Vibrio parahaemolyticus.

PubMed

Akeda, Yukihiro; Okayama, Kanna; Kimura, Tomomi; Dryselius, Rikard; Kodama, Toshio; Oishi, Kazunori; Iida, Tetsuya; Honda, Takeshi

2009-07-01

Vibrio parahaemolyticus causes human gastroenteritis. Genomic sequencing of this organism has revealed that it has two sets of type III secretion systems, T3SS1 and T3SS2, both of which are important for its pathogenicity. However, the mechanism of protein secretion via T3SSs is unknown. A characteristic of many effectors is that they require specific chaperones for efficient delivery via T3SSs; however, no chaperone has been experimentally identified in the T3SSs of V. parahaemolyticus. In this study, we identified candidate T3SS1-associated chaperones from genomic sequence data and examined their roles in effector secretion/translocation and binding to their cognate substrates. From these experiments, we concluded that there is a T3S-associated chaperone, VecA, for a cytotoxic T3SS1-dependent effector, VepA. Further analysis using pulldown and secretion assays characterized the chaperone-binding domain encompassing the first 30-100 amino acids and an amino terminal secretion signal encompassing the first 5-20 amino acids on VepA. These findings will provide a strategy to clarify how the T3SS1 of V. parahaemolyticus secretes its specific effectors.

Secretome of obligate intracellular Rickettsia

PubMed Central

Gillespie, Joseph J.; Kaur, Simran J.; Rahman, M. Sayeedur; Rennoll-Bankert, Kristen; Sears, Khandra T.; Beier-Sexton, Magda; Azad, Abdu F.

2014-01-01

The genus Rickettsia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) is comprised of obligate intracellular parasites, with virulent species of interest both as causes of emerging infectious diseases and for their potential deployment as bioterrorism agents. Currently, there are no effective commercially available vaccines, with treatment limited primarily to tetracycline antibiotics, although others (e.g. josamycin, ciprofloxacin, chloramphenicol, and azithromycin) are also effective. Much of the recent research geared toward understanding mechanisms underlying rickettsial pathogenicity has centered on characterization of secreted proteins that directly engage eukaryotic cells. Herein, we review all aspects of the Rickettsia secretome, including six secretion systems, 19 characterized secretory proteins, and potential moonlighting proteins identified on surfaces of multiple Rickettsia species. Employing bioinformatics and phylogenomics, we present novel structural and functional insight on each secretion system. Unexpectedly, our investigation revealed that the majority of characterized secretory proteins have not been assigned to their cognate secretion pathways. Furthermore, for most secretion pathways, the requisite signal sequences mediating translocation are poorly understood. As a blueprint for all known routes of protein translocation into host cells, this resource will assist research aimed at uniting characterized secreted proteins with their apposite secretion pathways. Furthermore, our work will help in the identification of novel secreted proteins involved in rickettsial ‘life on the inside’. PMID:25168200

45 CFR 310.25 - What conditions apply to acquisitions of Computerized Tribal IV-D Systems?

Code of Federal Regulations, 2010 CFR

2010-10-01

... FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES COMPUTERIZED TRIBAL IV-D SYSTEMS AND OFFICE AUTOMATION... Acquisition Threshold; (c) Software and ownership rights. (1) All procurement and contract instruments must... Computerized Tribal IV-D System software or enhancements thereof and all associated documentation designed...

[Rational therapy of Type II diabetes].

PubMed

Hanefeld, M; Fischer, S

1996-12-01

Noninsulin-dependent diabetes mellitus is a genetically determined form of diabetes, due to impaired insulin secretion by the B-cells as well as to insulin resistance of the peripheral tissues. According to the glucose toxicity theory hyperglycemia and hyperinsulinemia exist in a vicious circle. Therefore, it is a major therapeutical aim to put the B-cell to rest and improve insulin sensitivity by a strict control of fasting blood glucose and of postprandial hyperglycemia. Furthermore, associated abnormalities within the metabolic syndrome, such as hypertension, dyslipoproteinemia and hemostatic disorders should be corrected to avoid vessel complications. Therefore, it should be started with basic measures as body weight reduction, carbohydrate-rich and fat-poor diet and exercise. If these measures fail to achieve acceptable glycemic control, antihyperglycemic drugs (acarbose, metformin) are indicated, eventually in a combination with small doses of short-acting sulfonylureas. Further impairment of insulin secretion is the indication for sulfonylurea and/or insulin application. HbA1c of 7 to 7.5% should be the goal of antidiabetic therapy, also for patients in advanced age. The main criterion for the choice of antidiabetics is the present insulin secretion capacity. Simple indicators in this respect are changes of body weight, plasma triglycerides and C-Peptide after i.v. glucagon stimulation. Application of insulin in combination with other antidiabetics or in the form of intensified insulin therapy should not be too much postponed.

Chronic Consumption of Sweeteners and Its Effect on Glycaemia, Cytokines, Hormones, and Lymphocytes of GALT in CD1 Mice

PubMed Central

Ramírez-Durán, Ninfa

2018-01-01

Background The consumption of sweeteners has increased in recent years, being used to control body weight and blood glucose. However, they can cause increased appetite, modification of immune function, and secretion of hormones in the GALT. Objective To assess the effect of chronic sweetener consumption on glycaemia, cytokines, hormones, and GALT lymphocytes in CD1 mice. Material and Methods 72 CD1 mice divided into 3 groups were used: (a) baseline, (b) middle, and (c) final. Groups (b) and (c) were divided into 4 subgroups: (i) Control, (ii) Sucrose, (iii) Sucralose, and (iv) Stevia. The following were determined: body weight, hormones (GIP, insulin, and leptin), lymphocytes CD3+T cells and CD19+B cells, IgA+ plasma cells, and cytokines (IL-4, IL-5, IFN-γ, and TNF-α). Results Sucralose reduces secretion of GIP and glycaemia but does not modify insulin concentration, increases body weight, and reduces food intake. Stevia increases the secretion of GIP, insulin, leptin, body weight, and glycaemia but keeps food consumption normal. Sucralose and Stevia showed a higher percentage of CD3+T cells, CD19+B cells, and IgA+ plasma cells in Peyer's patches, but only Stevia in lamina propria. Conclusion Sweeteners modulate the hormonal response of cytokines and the proliferation of lymphocytes in the intestinal mucosa. PMID:29854725

45 CFR 310.25 - What conditions apply to acquisitions of Computerized Tribal IV-D Systems?

Code of Federal Regulations, 2014 CFR

2014-10-01

... acquisitions of Computerized Tribal IV-D Systems? (a) APD Approval. A comprehensive Tribal IV-D agency must... include a clause that provides that the comprehensive Tribal IV-D agency will have all ownership rights to... use and to authorize others to use for Federal Government purposes, such software, modifications and...

45 CFR 310.25 - What conditions apply to acquisitions of Computerized Tribal IV-D Systems?

Code of Federal Regulations, 2011 CFR

2011-10-01

... acquisitions of Computerized Tribal IV-D Systems? (a) APD Approval. A comprehensive Tribal IV-D agency must... include a clause that provides that the comprehensive Tribal IV-D agency will have all ownership rights to... use and to authorize others to use for Federal Government purposes, such software, modifications and...

45 CFR 310.25 - What conditions apply to acquisitions of Computerized Tribal IV-D Systems?

Code of Federal Regulations, 2013 CFR

2013-10-01

... acquisitions of Computerized Tribal IV-D Systems? (a) APD Approval. A comprehensive Tribal IV-D agency must... include a clause that provides that the comprehensive Tribal IV-D agency will have all ownership rights to... use and to authorize others to use for Federal Government purposes, such software, modifications and...

Self-sensing in Bacillus subtilis quorum-sensing systems

PubMed Central

Bareia, Tasneem; Pollak, Shaul; Eldar, Avigdor

2017-01-01

Bacterial cell-cell signaling, or quorum sensing, is characterized by the secretion and group-wide detection of small diffusible signal molecules called autoinducers. This mechanism allows cells to coordinate their behavior in a density-dependent manner. A quorum-sensing cell may directly respond to the autoinducers it produces in a cell-autonomous and quorum-independent manner, but the strength of such self-sensing effect and its impact on bacterial physiology are unclear. Here, we explored the existence and impact of self-sensing in the Bacillus subtilis ComQXP and Rap-Phr quorum-sensing systems. By comparing the quorum-sensing response of autoinducer-secreting and non-secreting cells in co-culture, we found that secreting cells consistently showed a stronger response than non-secreting cells. Combining genetic and quantitative analyses, we demonstrated this effect to be a direct result of self-sensing and ruled out an indirect regulatory effect of the autoinducer production genes on response sensitivity. In addition, self-sensing in the ComQXP system affected persistence to antibiotic treatment. Together, these findings indicate the existence of self-sensing in the two most common designs of quorum-sensing systems of Gram-positive bacteria. PMID:29038467

Edwardsiella tarda EscE (Orf13 Protein) Is a Type III Secretion System-Secreted Protein That Is Required for the Injection of Effectors, Secretion of Translocators, and Pathogenesis in Fish.

PubMed

Lu, Jin Fang; Wang, Wei Na; Wang, Gai Ling; Zhang, He; Zhou, Ying; Gao, Zhi Peng; Nie, Pin; Xie, Hai Xia

2016-01-01

The type III secretion system (T3SS) of Edwardsiella tarda is crucial for its intracellular survival and pathogenesis in fish. The orf13 gene (escE) of E. tarda is located 84 nucleotides (nt) upstream of esrC in the T3SS gene cluster. We found that EscE is secreted and translocated in a T3SS-dependent manner and that amino acids 2 to 15 in the N terminus were required for a completely functional T3SS in E. tarda. Deletion of escE abolished the secretion of T3SS translocators, as well as the secretion and translocation of T3SS effectors, but did not influence their intracellular protein levels in E. tarda. Complementation of the escE mutant with a secretion-incompetent EscE derivative restored the secretion of translocators and effectors. Interestingly, the effectors that were secreted and translocated were positively correlated with the EscE protein level in E. tarda. The escE mutant was attenuated in the blue gourami fish infection model, as its 50% lethal dose (LD50) increased to 4 times that of the wild type. The survival rate of the escE mutant-strain-infected fish was 69%, which was much higher than that of the fish infected with the wild-type bacteria (6%). Overall, EscE represents a secreted T3SS regulator that controls effector injection and translocator secretion, thus contributing to E. tarda pathogenesis in fish. The homology of EscE within the T3SSs of other bacterial species suggests that the mechanism of secretion and translocation control used by E. tarda may be commonly used by other bacterial pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Oxytocin-secreting system: A major part of the neuroendocrine center regulating immunologic activity.

PubMed

Wang, Ping; Yang, Hai-Peng; Tian, Shujun; Wang, Liwei; Wang, Stephani C; Zhang, Fengmin; Wang, Yu-Feng

2015-12-15

Interactions between the nervous system and immune system have been studied extensively. However, the mechanisms underlying the neural regulation of immune activity, particularly the neuroendocrine regulation of immunologic functions, remain elusive. In this review, we provide a comprehensive examination of current evidence on interactions between the immune system and hypothalamic oxytocin-secreting system. We highlight the fact that oxytocin may have significant effects in the body, beyond its classical functions in lactation and parturition. Similar to the hypothalamo-pituitary-adrenal axis, the oxytocin-secreting system closely interacts with classical immune system, integrating both neurochemical and immunologic signals in the central nervous system and in turn affects immunologic defense, homeostasis, and surveillance. Lastly, this review explores therapeutic potentials of oxytocin in treating immunologic disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of addition order and contact time on thorium(IV) retention by hematite in the presence of humic acids.

PubMed

Reiller, Pascal; Casanova, Florence; Moulin, Valérie

2005-03-15

The influence of addition order and contact time in the system hematite (alpha-Fe2O3)-humic acid (HA)-thorium(IV) (Th(IV)) was studied in batch experiments. Th(IV) is considered here as a chemical analogue of other actinides (IV). The sorption isotherms were acquired varying pH in the range 2-10 and HA concentration in the range 1-100 mg/L. As already observed by numerous authors, Th(IV) retention was hindered when HA and hematite were equilibrated beforehand during 24 h. As it has been observed in a previous study, this effect was drastic when the ratio between humic and surface (iron oxide) sites exceeds a critical value. However, when HA was added after a 24-h equilibration of the hematite-Th(IV) system, Th(IV) was barely desorbed from the iron oxide surface. Furthermore, no drastic effect of the ratio between humic and surface sites could be evidenced, as the increase of HA concentration only results in a slight monotonic decrease in Th(IV) retention. Increasing contact time between components of the systems only indicated slight Th(IV) retention variation. This was interpreted as a consequence of slow kinetic controls of both the Th(IV)-HA complexation and HA-hematite sorption.

Conjugative DNA Transfer Is Enhanced by Plasmid R1 Partitioning Proteins

PubMed Central

Gruber, Christian J.; Lang, Silvia; Rajendra, Vinod K. H.; Nuk, Monika; Raffl, Sandra; Schildbach, Joel F.; Zechner, Ellen L.

2016-01-01

Bacterial conjugation is a form of type IV secretion used to transport protein and DNA directly to recipient bacteria. The process is cell contact-dependent, yet the mechanisms enabling extracellular events to trigger plasmid transfer to begin inside the cell remain obscure. In this study of plasmid R1 we investigated the role of plasmid proteins in the initiation of gene transfer. We find that TraI, the central regulator of conjugative DNA processing, interacts physically, and functionally with the plasmid partitioning proteins ParM and ParR. These interactions stimulate TraI catalyzed relaxation of plasmid DNA in vivo and in vitro and increase ParM ATPase activity. ParM also binds the coupling protein TraD and VirB4-like channel ATPase TraC. Together, these protein-protein interactions probably act to co-localize the transfer components intracellularly and promote assembly of the conjugation machinery. Importantly these data also indicate that the continued association of ParM and ParR at the conjugative pore is necessary for plasmid transfer to start efficiently. Moreover, the conjugative pilus and underlying secretion machinery assembled in the absence of Par proteins mediate poor biofilm formation and are completely dysfunctional for pilus specific R17 bacteriophage uptake. Thus, functional integration of Par components at the interface of relaxosome, coupling protein, and channel ATPases appears important for an optimal conformation and effective activation of the transfer machinery. We conclude that low copy plasmid R1 has evolved an active segregation system that optimizes both its vertical and lateral modes of dissemination. PMID:27486582

Extensive recombination events and horizontal gene transfer shaped the Legionella pneumophila genomes

PubMed Central

2011-01-01

Background Legionella pneumophila is an intracellular pathogen of environmental protozoa. When humans inhale contaminated aerosols this bacterium may cause a severe pneumonia called Legionnaires' disease. Despite the abundance of dozens of Legionella species in aquatic reservoirs, the vast majority of human disease is caused by a single serogroup (Sg) of a single species, namely L. pneumophila Sg1. To get further insights into genome dynamics and evolution of Sg1 strains, we sequenced strains Lorraine and HL 0604 1035 (Sg1) and compared them to the available sequences of Sg1 strains Paris, Lens, Corby and Philadelphia, resulting in a comprehensive multigenome analysis. Results We show that L. pneumophila Sg1 has a highly conserved and syntenic core genome that comprises the many eukaryotic like proteins and a conserved repertoire of over 200 Dot/Icm type IV secreted substrates. However, recombination events and horizontal gene transfer are frequent. In particular the analyses of the distribution of nucleotide polymorphisms suggests that large chromosomal fragments of over 200 kbs are exchanged between L. pneumophila strains and contribute to the genome dynamics in the natural population. The many secretion systems present might be implicated in exchange of these fragments by conjugal transfer. Plasmids also play a role in genome diversification and are exchanged among strains and circulate between different Legionella species. Conclusion Horizontal gene transfer among bacteria and from eukaryotes to L. pneumophila as well as recombination between strains allows different clones to evolve into predominant disease clones and others to replace them subsequently within relatively short periods of time. PMID:22044686

The insulin secretagogues glibenclamide and repaglinide do not influence growth hormone secretion in humans but stimulate glucagon secretion during profound insulin deficiency.

PubMed

Østergård, Torben; Degn, Kristine B; Gall, Mari-Anne; Carr, Richard D; Veldhuis, Johannes D; Thomsen, Mads K; Rizza, Robert A; Schmitz, Ole

2004-01-01

In vitro data have recently suggested that sulfonylureas (SUs) enhance GH secretion by modulating the effects of GHRH and somatostatin in pituitary cells. The present study was undertaken to explore in more detail a possible influence of a single dose of SU (glibenclamide) and a non-SU (repaglinide) insulin secretagogue on circulating GH dynamics. Ten C-peptide-negative type 1 diabetic individuals were examined on three occasions in random order. Either glibenclamide (10.5 mg), repaglinide (8 mg), or placebo was administered after overnight normalization of plasma glucose by iv insulin infusion. Subsequently, GH concentrations were measured regularly after stimulation with GHRH (bolus 0.1 micro g/kg) alone and during concomitant infusion with somatostatin (7 ng.kg(-1).min(-1)). Insulin was replaced at baseline levels (0.25 mU.kg(-1).min(-1)) and plasma glucose clamped at 5-6 mmol/liter. Overall, there were no significant statistical differences in GH responses determined as either GH peak concentrations, integrated levels of GH, or secretory burst mass of GH during the experimental protocol. In contrast, plasma glucagon concentrations were significantly increased during glibenclamide and repaglinide exposure. The present experimental design does not support the hypothesis that acute administration of pharmacological doses of the oral antihyperglycemic agents glibenclamide and repaglinide per se enhance GH release in humans. Additionally, this study shows that these potassium channel inhibitors seem to stimulate glucagon secretion in people who have severe intraislet insulin deficiency (e.g. type 1 diabetes). However, extrapolation of our findings to type 2 diabetic individuals should be done with some caution.

Submaximal doses of ghrelin do not inhibit gonadotrophin levels but stimulate prolactin secretion in postmenopausal women.

PubMed

Messini, Christina I; Malandri, Maria; Anifandis, George; Dafopoulos, Konstantinos; Georgoulias, Panagiotis; Sveronis, Georgios; Garas, Antonios; Daponte, Alexandros; Messinis, Ioannis E

2017-07-01

An inhibitory effect of ghrelin on gonadotrophin secretion has been reported in normally menstruating women possibly modulated by endogenous oestrogen. The aim of this study was to examine the effect of ghrelin on gonadotrophin and prolactin (PRL) secretion in oestrogen-deprived postmenopausal women. Prospective intervention study. Ten healthy postmenopausal volunteer women were studied during two 15-days periods of oestrogen treatment (A and B) a month apart. Four experiments (Exp) were performed in total, two on day 1 (Exp 1A and Exp 1B) and two on day 15 (Exp 15A and Exp 15B) of the two periods. The women received in Exp 1A and in Exp 15A two iv injections of ghrelin (0.15 μg/kg at time 0 minute and 0.30 μg/kg at time 90 minutes) and in Exp1B and in Exp 15B normal saline (2 mL), respectively. Blood samples were taken at -15, 0, 30, 60, 90, 120, 150 and 180 minutes. After oestrogen treatment, late follicular phase serum oestradiol levels were attained on day 15 of periods A and B. Ghrelin administration did not affect serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), whereas it increased significantly those of growth hormone (GH) and PRL. In Exp 15A, serum PRL increment in response to ghrelin (area under the curve, net increment) was significantly greater than in Exp 1A (P<.05). This study demonstrates for the first time that in oestrogen-deprived postmenopausal women, ghrelin administration affects neither FSH nor LH levels but stimulates PRL secretion, that is amplified by exogenous oestrogen administration. © 2017 John Wiley & Sons Ltd.

Catecholamine secretion by chemical hypoxia in guinea-pig, but not rat, adrenal medullary cells: differences in mitochondria.

PubMed

Harada, K; Endo, Y; Warashina, A; Inoue, M

2015-08-20

The effects of mitochondrial inhibitors (CN(-), a complex IV inhibitor and CCCP, protonophore) on catecholamine (CA) secretion and mitochondrial function were explored functionally and biochemically in rat and guinea-pig adrenal chromaffin cells. Guinea-pig chromaffin cells conspicuously secreted CA in response to CN(-) or CCCP, but rat cells showed a little, if any, secretory response to either of them. The resting metabolic rates in rat adrenal medullae did not differ from those in guinea-pig adrenal medullae. On the other hand, the time course of depolarization of the mitochondrial membrane potential (ΔΨm) in guinea-pig chromaffin cells in response to CN(-) was slower than that in rat chromaffin cells, and this difference was abolished by oligomycin, an F1F0-ATPase inhibitor. The extent of CCCP-induced decrease in cellular ATP in guinea-pig chromaffin cells, which was indirectly measured using a Mg(2+) indicator, was smaller than that in rat chromaffin cells. Relative expression levels of F1F0-ATPase inhibitor factor in guinea-pig adrenal medullae were smaller than in rat adrenal medullae, and the opposite was true for F1F0-ATPase α subunit. The present results indicate that guinea-pig chromaffin cells secrete more CA in response to a mitochondrial inhibitor than rat chromaffin cells and this higher susceptibility in the former is accounted for by a larger extent of reversed operation of F1F0-ATPase with the consequent decrease in ATP under conditions where ΔΨm is depolarized. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

45 CFR 310.15 - What are the safeguards and processes that comprehensive Tribal IV-D agencies must have in place...

Code of Federal Regulations, 2014 CFR

2014-10-01

... comprehensive Tribal IV-D agencies must have in place to ensure the security and privacy of Computerized Tribal... ensure the security and privacy of Computerized Tribal IV-D Systems and Office Automation? (a..., accuracy, completeness, access to, and use of data in the Computerized Tribal IV-D System and Office...

Expression, Extracellular Secretion, and Immunogenicity of the Plasmodium falciparum Sporozoite Surface Protein 2 in Salmonella Vaccine Strains

PubMed Central

Gómez-Duarte, Oscar G.; Pasetti, Marcela F.; Santiago, Araceli; Sztein, Marcelo B.; Hoffman, Stephen L.; Levine, Myron M.

2001-01-01

Deleting transmembrane α-helix motifs from Plasmodium falciparum sporozoite surface protein (SSP-2) allowed its secretion from Salmonella enterica serovar Typhimurium SL3261 and S. enterica serovar Typhi CVD 908-htrA by the Hly type I secretion system. In mice immunized intranasally, serovar Typhimurium constructs secreting SSP-2 stimulated greater gamma interferon splenocyte responses than did nonsecreting constructs (P = 0.04). PMID:11160021

45 CFR 310.5 - What options are available for Computerized Tribal IV-D Systems and office automation?

Code of Federal Regulations, 2010 CFR

2010-10-01

... to conduct automated data processing and recordkeeping activities through Office Automation... IV-D Systems and office automation? 310.5 Section 310.5 Public Welfare Regulations Relating to Public... AUTOMATION Requirements for Computerized Tribal IV-D Systems and Office Automation § 310.5 What options are...

Arginine potentiates the GHRH- but not the pyridostigmine-induced GH secretion in normal short children. Further evidence for a somatostatin suppressing effect of arginine.

PubMed

Ghigo, E; Bellone, J; Mazza, E; Imperiale, E; Procopio, M; Valente, F; Lala, R; De Sanctis, C; Camanni, F

1990-06-01

To investigate the mechanism underlying the GH-releasing effect of arginine (ARG), we studied the interactions of ARG (0.5 g/kg infused i.v. over 30 min) with GHRH (1 microgram/kg i.v.) and with pyridostigmine (PD, 60 mg orally) on GH secretion in 15 children and adolescents with familial short stature (5.1-15.4 years). In a group of eight subjects ARG induced a GH increase not statistically different to that observed after GHRH (peak, mean +/- SEM: 38.0 +/- 10.4 vs 64.0 +/- 14.4 mU/l). The combined administration of ARG and GHRH led to GH levels (101 +/- 15.2 mU/l) higher than those observed after GHRH (P less than 0.025) or ARG alone (P less than 0.001) and overlapping with those recorded after combined PD and GHRH administration (111 +/- 22.4 mU/l). In the other seven subjects, ARG and PD administration induced a similar GH response either when administered alone (25.2 +/- 13.6 and 27.8 +/- 4.0 mU/l, respectively) or in combination (33.8 +/- 5.4 mU/l). In conclusion, our results show that in children ARG administration potentiates GHRH- but not PD-induced GH increase. These findings agree with the hypothesis that the GH-releasing effect of both ARG and PD is mediated via the same mechanism, namely, by suppression of endogeneous somatostatin release. Combined administration of either ARG or PD with GHRH has a similar striking GH-releasing effect which is clearly higher than that of GHRH alone.

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

Zhang, Ling; Wang, Lin; Meng, Zhiyun

Highlights: • E2HSA has an extended half-life and good plasma stability. • E2HSA could improve glucose-dependent insulin secretion. • E2HSA has excellent glucoregulatory effects in vivo. • E2HSA could potentially be used as a new long-acting GLP-1 receptor agonist for type 2 diabetes management. - Abstract: Glucagon-like peptide-1 (GLP-1) has attracted considerable research interest in terms of the treatment of type 2 diabetes due to their multiple glucoregulatory functions. However, the short half-life, rapid inactivation by dipeptidyl peptidase-IV (DPP-IV) and excretion, limits the therapeutic potential of the native incretin hormone. Therefore, efforts are being made to develop the long-acting incretinmore » mimetics via modifying its structure. Here we report a novel recombinant exendin-4 human serum albumin fusion protein E2HSA with HSA molecule extends their circulatory half-life in vivo while still retaining exendin-4 biological activity and therapeutic properties. In vitro comparisons of E2HSA and exendin-4 showed similar insulinotropic activity on rat pancreatic islets and GLP-1R-dependent biological activity on RIN-m5F cells, although E2HSA was less potent than exendin-4. E2HSA had a terminal elimation half-life of approximate 54 h in healthy rhesus monkeys. Furthermore, E2HSA could reduce postprandial glucose excursion and control fasting glucose level, dose-dependent suppress food intake. Improvement in glucose-dependent insulin secretion and control serum glucose excursions were observed during hyperglycemic clamp test (18 h) and oral glucose tolerance test (42 h) respectively. Thus the improved physiological characterization of E2HSA make it a new potent anti-diabetic drug for type 2 diabetes therapy.« less

Lessons learned from a randomized trial of airway secretion clearance techniques in cystic fibrosis

PubMed Central

Sontag, Marci K.; Quittner, Alexandra L.; Modi, Avani C.; Koenig, Joni M.; Giles, Don; Oermann, Christopher M.; Konstan, Michael W.; Castile, Robert; Accurso, Frank J.

2014-01-01

Rationale Airway secretion clearance therapies are a cornerstone of cystic fibrosis care, however longitudinal comparative studies are rare. Our objectives were to compare three therapies [postural drainage and percussion: (postural drainage), flutter device, and high frequency chest wall oscillation: (vest)], by studying 1) change in pulmonary function; 2) time to need for IV antibiotics, 3) use of pulmonary therapies, 4) adherence to treatment, 5) treatment satisfaction, and 6) quality of life. Methods Participants were randomly assigned to one of three therapies twice daily. Clinical outcomes were assessed quarterly over 3 years. Results Enrollment goals were not met, and withdrawal rates were high, especially in postural drainage (51%) and flutter device (26%), compared to vest (9%), resulting in early termination. FEV1 decline, time to need IV antibiotics, and other pulmonary therapies were not different. The annual FEF25–75% predicted rate of decline was greater in those using vest (p=0.02). Adherence was not significantly different (p=0.09). Overall treatment satisfaction was higher in vest and flutter device than in postural drainage (p<0.05). Health-related quality of life was not different. The rate of FEV1 decline was 1.23% predicted/year. Conclusions The study was ended early due to dropout and smaller than expected decline in FEV1. Patients were more satisfied with vest and flutter device. The longitudinal decline in FEF25–75% was faster in vest; we found no other difference in lung function decline, taken together this warrants further study. The slow decline in FEV1 illustrates the difficulty with FEV1 decline as a clinical trial outcome. PMID:20146387

Increased adrenal steroid secretion in response to CRF in women with hypothalamic amenorrhea.

PubMed

Genazzani, A D; Bersi, C; Luisi, S; Fruzzetti, F; Malavasi, B; Luisi, M; Petraglia, F; Genazzani, A R

2001-09-01

To evaluate adrenal steroid hormone secretion in response to corticotropin-releasing factor (CRF) or to adrenocorticotropin hormone in women with hypothalamic amenorrhea. Controlled clinical study. Department of Reproductive Medicine and Child Development, Section of Gynecology and Obstetrics, University of Pisa, Italy. Fifteen women with hypothalamic amenorrhea were enrolled in the study. Eight normal cycling women were used as control group. Blood samples were collected before and after an injection of ovine CRF (0.1 microg/kg iv bolus) or after synthetic ACTH (0.25 mg iv). Plasma levels of ACTH, 17-hydroxypregnenolone (17OHPe), progesterone (P), dehydroepiandrosterone (DHEA), 17-hydroxyprogesterone (17OHP), cortisol (F), 11-deoxycortisol (S) and androstenedione (A). Basal plasma concentrations of ACTH, cortisol, 11-deoxycortisol, DHEA and 17OHPe were significantly higher in patients than in controls, whereas plasma levels of progesterone and 17-OHP were significantly lower in patients than in controls. In amenorrheic women the ratio of 17-OHPe/DHEA, of 17-OHPe/17-OHP and of 11-deoxycortisol/cortisol were significantly higher than in controls, while a significant reduction in the ratio of 17-OHP/androstenedione, of 17-OHP/11-deoxycortisol was obtained. In response to corticotropin-releasing factor test, plasma levels of ACTH, cortisol, 17-OHP, 11-deoxycortisol, DHEA and androstenedione were significantly lower in patients than in controls. In response to adrenocorticotropin hormone, plasma levels of 17-OHP, androstenedione and androstenedione/cortisol were significantly higher in patients than in controls. Patients suffering for hypothalamic amenorrhea showed an increased activation of hypothalamus-pituitary-adrenal (HPA) axis, as shown by the higher basal levels and by augmented adrenal hormone response to corticotropin-releasing factor administration. These data suggest a possible derangement of adrenal androgen enzymatic pathway.

A Trypanosoma cruzi-secreted 80 kDa proteinase with specificity for human collagen types I and IV.

PubMed Central

Santana, J M; Grellier, P; Schrével, J; Teixeira, A R

1997-01-01

Specific interactions between parasites and extracellular matrix components are an important mechanism in the dissemination of Chagas' disease. Binding of the extracellular matrix proteins to Trypanosoma cruzi receptors has been described as a significant step in this phenomenon. In this study, a specific proteinase activity was identified in cell-free extracts of amastigote, trypomastigote and epimastigote forms of T. cruzi using the collagenase fluorogenic substrate N-Suc-Gly-Pro-Leu-Gly-Pro-7-amido-4-methylcoumarin. Isolation of this activity was achieved by a four-step FPLC procedure. Optimal enzyme activity was found to occur at pH 8.0 and was associated with a single T. cruzi 80 kDa protein (Tc 80 proteinase) on SDS/PAGE under reducing conditions. An internal peptide sequence of Tc 80 proteinase was obtained (AGDNYTPPE), and no similarity was found to previously described proteinases of T. cruzi. This enzyme activity is strongly inhibited by HgCl2, tosyl-lysylchloromethane ('TLCK') p-chloromercuribenzoate and benzyloxycarbonyl-Phe-Ala-diazomethane. The purified enzyme was able to hydrolyse purified human [14C]collagen types I and IV at neutral pH, but not 14C-labelled BSA, rat laminin, rabbit IgG or small proteins such as insulin or cytochrome c. In addition, Tc 80 proteinase activity was found to be secreted by T. cruzi forms infective to mammalian cells. Furthermore we demonstrated that purified Tc 80 proteinase mediates native collagen type I hydrolysis in rat mesentery. This feature is compared with that of Clostridium histolyticum collagenase. These findings suggest that Tc 80 proteinase may facilitate T. cruzi host-cell infection by degrading the collagens of the extracellular matrix and could represent a good target for Chagas' disease chemotherapy. PMID:9224638

Inhibition of leptin-induced vascular extracellular matrix remodelling by adiponectin.

PubMed

Zhang, Zhi; Wang, Fang; Wang, Bing-Jian; Chu, Guang; Cao, Qunan; Sun, Bao-Gui; Dai, Qiu-Yan

2014-10-01

Vascular extracellular matrix (ECM) remodelling, which is the result of disruption in the balance of ECM synthesis and degradation, induces vessel fibrosis and thereby leads to hypertension. Leptin is known to promote tissue fibrosis, while adiponectin has recently been demonstrated to be anti-fibrogenic in tissue fibrosis. In this study, we aimed to evaluate the leptin-antagonist function of adiponectin and to further elucidate the mechanisms through which adiponectin dampens leptin signalling in vascular smooth muscle cells, thus preventing excess ECM production, in our already established 3D co-culture vessel models. Our 3D co-culture vessel model, which mimics true blood vessels, is composed of vascular endothelial cells, vascular smooth muscle cells and collagen type I. We validated the profibrogenic effects of leptin and analysed matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase 1 (TIMP1) and collagen types II/IV secretion in 3D vessel models. The protective/inhibitory effects of adiponectin were re-analysed by inhibiting adiponectin receptor 1 (AdipoR) and AdipoR2 expression in endothelial cells using RNAi technology. In the 3D vessel models, adiponectin blocked the leptin-stimulated secretion of collagen types II/IV and TIMP1 while significantly increasing MMP2/9 activity. In endothelial cells, adiponectin induced phosphorylation of AMPK, thereby suppressing leptin-mediated STAT3 phosphorylation through induction of SOCS3 in smooth muscle cells. Our findings indicate that adiponectin disrupted the leptin-induced vascular ECM remodelling via AdipoR1 and enhanced AMPK signalling in endothelial cells, which, in turn, promoted SOCS3 up-regulation in smooth muscle cells to repress leptin-stimulated phosphorylation of STAT3. © 2014 The authors.

Inhibition of leptin-induced vascular extracellular matrix remodelling by adiponectin

PubMed Central

Zhang, Zhi; Wang, Fang; Wang, Bing-jian; Chu, Guang; Cao, Qunan; Sun, Bao-Gui; Dai, Qiu-Yan

2014-01-01

Vascular extracellular matrix (ECM) remodelling, which is the result of disruption in the balance of ECM synthesis and degradation, induces vessel fibrosis and thereby leads to hypertension. Leptin is known to promote tissue fibrosis, while adiponectin has recently been demonstrated to be anti-fibrogenic in tissue fibrosis. In this study, we aimed to evaluate the leptin-antagonist function of adiponectin and to further elucidate the mechanisms through which adiponectin dampens leptin signalling in vascular smooth muscle cells, thus preventing excess ECM production, in our already established 3D co-culture vessel models. Our 3D co-culture vessel model, which mimics true blood vessels, is composed of vascular endothelial cells, vascular smooth muscle cells and collagen type I. We validated the profibrogenic effects of leptin and analysed matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor of metalloproteinase 1 (TIMP1) and collagen types II/IV secretion in 3D vessel models. The protective/inhibitory effects of adiponectin were re-analysed by inhibiting adiponectin receptor 1 (AdipoR) and AdipoR2 expression in endothelial cells using RNAi technology. In the 3D vessel models, adiponectin blocked the leptin-stimulated secretion of collagen types II/IV and TIMP1 while significantly increasing MMP2/9 activity. In endothelial cells, adiponectin induced phosphorylation of AMPK, thereby suppressing leptin-mediated STAT3 phosphorylation through induction of SOCS3 in smooth muscle cells. Our findings indicate that adiponectin disrupted the leptin-induced vascular ECM remodelling via AdipoR1 and enhanced AMPK signalling in endothelial cells, which, in turn, promoted SOCS3 up-regulation in smooth muscle cells to repress leptin-stimulated phosphorylation of STAT3. PMID:24982243

C-type natriuretic peptide suppresses mesangial proliferation and matrix expression via a MMPs/TIMPs-independent pathway in vitro.

PubMed

Huang, Bao Yu; Hu, Peng; Zhang, Dong Dong; Jiang, Guang Mei; Liu, Si Yan; Xu, Yao; Wu, Yang Fang; Xia, Xun; Wang, Ya

2017-08-01

C-type natriuretic peptide (CNP) acts mainly in a local, paracrine fashion to regulate vascular tone and cell proliferation. Although several in vivo studies have demonstrated that CNP exerts an inhibitory effect on mesangial matrix generation, a limited number of reports exist about the anti-extracellular matrix (ECM) accumulation effect of CNP and its underlying mechanisms in mesangial cells (MCs) in vitro. In this study, human MCs were incubated in serum-containing medium in the absence or presence of CNP (0, 10 and 100 pM) for 24, 48 and 72 h, respectively. CNP administration significantly suppresses MCs proliferation and collagen (Col)-IV expression in a time- and dose-dependent manner. In addition, the study presented herein was designed as a first demonstration of the regulative effects of CNP on the metabolisms of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in MCs in vitro, and found that: (1) CNP administration significantly decreased the secretion and expression of MMP-2 and MMP-9 in the cultured MCs; (2) the secretion and expression of TIMP-1 progressively elevated after treatment with CNP for 24 and 48 h, whereas declined at later time point; (3) CNP expression was negatively correlated with MMP-2 and MMP-9 expression; (4) the balance of MMPs/TIMPs was shifted toward the reduction in MMP-2 and MMP-9 activity and/or the increment in TIMP-1 expression, which could not account for the down-regulation of Col-IV expression in CNP-treated MCs. In conclusion, CNP suppresses mesangial proliferation and ECM expression via a MMPs/TIMPs-independent pathway in vitro.

Regulation and specificity of antifungal metapleural gland secretion in leaf-cutting ants

PubMed Central

Yek, Sze Huei; Nash, David R.; Jensen, Annette B.; Boomsma, Jacobus J.

2012-01-01

Ants have paired metapleural glands (MGs) to produce secretions for prophylactic hygiene. These exocrine glands are particularly well developed in leaf-cutting ants, but whether the ants can actively regulate MG secretion is unknown. In a set of controlled experiments using conidia of five fungi, we show that the ants adjust the amount of MG secretion to the virulence of the fungus with which they are infected. We further applied fixed volumes of MG secretion of ants challenged with constant conidia doses to agar mats of the same fungal species. This showed that inhibition halos were significantly larger for ants challenged with virulent and mild pathogens/weeds than for controls and Escovopsis-challenged ants. We conclude that the MG defence system of leaf-cutting ants has characteristics reminiscent of an additional cuticular immune system, with specific and non-specific components, of which some are constitutive and others induced. PMID:22915672

Environmental mimics and the Lvh type IVA secretion system contribute to virulence-related phenotypes of Legionella pneumophila.

PubMed

Bandyopadhyay, Purnima; Liu, Shuqing; Gabbai, Carolina B; Venitelli, Zeah; Steinman, Howard M

2007-02-01

Legionella pneumophila, the causative organism of Legionnaires' disease, is a fresh-water bacterium and intracellular parasite of amoebae. This study examined the effects of incubation in water and amoeba encystment on L. pneumophila strain JR32 and null mutants in dot/icm genes encoding a type IVB secretion system required for entry, delayed acidification of L. pneumophila-containing phagosomes, and intracellular multiplication when stationary-phase bacteria infect amoebae and macrophages. Following incubation of stationary-phase cultures in water, mutants in dotA and dotB, essential for function of the type IVB secretion system, exhibited entry and delay of phagosome acidification comparable to that of strain JR32. Following encystment in Acanthamoeba castellanii and reversion of cysts to amoeba trophozoites, dotA and dotB mutants exhibited intracellular multiplication in amoebae. The L. pneumophila Lvh locus, encoding a type IVA secretion system homologous to that in Agrobacterium tumefaciens, was required for restoration of entry and intracellular multiplication in dot/icm mutants following incubation in water and amoeba encystment and was required for delay of phagosome acidification in strain JR32. These data support a model in which the Dot/Icm type IVB secretion system is conditionally rather than absolutely required for L. pneumophila virulence-related phenotypes. The data suggest that the Lvh type IVA secretion system, previously thought to be dispensable, is involved in virulence-related phenotypes under conditions mimicking the spread of Legionnaires' disease from environmental niches. Since environmental amoebae are implicated as reservoirs for an increasing number of environmental pathogens and for drug-resistant bacteria, the environmental mimics developed here may be useful in virulence studies of other pathogens.

Porphyromonas gingivalis and related bacteria: from colonial pigmentation to the type IX secretion system and gliding motility

PubMed Central

Nakayama, K

2015-01-01

Porphyromonas gingivalis is a gram-negative, non-motile, anaerobic bacterium implicated as a major pathogen in periodontal disease. P. gingivalis grows as black-pigmented colonies on blood agar, and many bacteriologists have shown interest in this property. Studies of colonial pigmentation have revealed a number of important findings, including an association with the highly active extracellular and surface proteinases called gingipains that are found in P. gingivalis. The Por secretion system, a novel type IX secretion system (T9SS), has been implicated in gingipain secretion in studies using non-pigmented mutants. In addition, many potent virulence proteins, including the metallocarboxypeptidase CPG70, 35 kDa hemin-binding protein HBP35, peptidylarginine deiminase PAD and Lys-specific serine endopeptidase PepK, are secreted through the T9SS. These findings have not been limited to P. gingivalis but have been extended to other bacteria belonging to the phylum Bacteroidetes. Many Bacteroidetes species possess the T9SS, which is associated with gliding motility for some of these bacteria. PMID:25546073

Assuring NASA's Safety and Mission Critical Software

NASA Technical Reports Server (NTRS)

Deadrick, Wesley

2015-01-01

What is IV&V? Independent Verification and Validation (IV&V) is an objective examination of safety and mission critical software processes and products. Independence: 3 Key parameters: Technical Independence; Managerial Independence; Financial Independence. NASA IV&V perspectives: Will the system's software: Do what it is supposed to do?; Not do what it is not supposed to do?; Respond as expected under adverse conditions?. Systems Engineering: Determines if the right system has been built and that it has been built correctly. IV&V Technical Approaches: Aligned with IEEE 1012; Captured in a Catalog of Methods; Spans the full project lifecycle. IV&V Assurance Strategy: The IV&V Project's strategy for providing mission assurance; Assurance Strategy is driven by the specific needs of an individual project; Implemented via an Assurance Design; Communicated via Assurance Statements.

High-Dimensional Circular Quantum Secret Sharing Using Orbital Angular Momentum

NASA Astrophysics Data System (ADS)

Tang, Dawei; Wang, Tie-jun; Mi, Sichen; Geng, Xiao-Meng; Wang, Chuan

2016-11-01

Quantum secret sharing is to distribute secret message securely between multi-parties. Here exploiting orbital angular momentum (OAM) state of single photons as the information carrier, we propose a high-dimensional circular quantum secret sharing protocol which increases the channel capacity largely. In the proposed protocol, the secret message is split into two parts, and each encoded on the OAM state of single photons. The security of the protocol is guaranteed by the laws of non-cloning theorem. And the secret messages could not be recovered except that the two receivers collaborated with each other. Moreover, the proposed protocol could be extended into high-level quantum systems, and the enhanced security could be achieved.

Secretion systems for secondary metabolites: how producer cells send out messages of intercellular communication.

PubMed

Martín, Juan F; Casqueiro, Javier; Liras, Paloma

2005-06-01

Many secondary metabolites (e.g. antibiotics and mycotoxins) are toxic to the microorganisms that produce them. The clusters of genes that are responsible for the biosynthesis of secondary metabolites frequently contain genes for resistance to these toxic metabolites, such as different types of multiple drug resistance systems, to avoid suicide of the producer strains. Recently there has been research into the efflux systems of secondary metabolites in bacteria and in filamentous fungi, such as the large number of ATP-binding cassette transporters found in antibiotic-producing Streptomyces species and that are involved in penicillin secretion in Penicillium chrysogenum. A different group of efflux systems, the major facilitator superfamily exporters, occur very frequently in a variety of bacteria that produce pigments or antibiotics (e.g. the cephamycin and thienamycin producers) and in filamentous fungi that produce mycotoxins. Such efflux systems include the CefT exporters that mediate cephalosporin secretion in Acremonium chrysogenum. The evolutionary origin of these efflux systems and their relationship with current resistance determinants in pathogenic bacteria has been analyzed. Genetic improvement of the secretion systems of secondary metabolites in the producer strain has important industrial applications.

Benefits of Genomic Insights and CRISPR-Cas Signatures to Monitor Potential Pathogens across Drinking Water Production and Distribution Systems

PubMed Central

Zhang, Ya; Kitajima, Masaaki; Whittle, Andrew J.; Liu, Wen-Tso

2017-01-01

The occurrence of pathogenic bacteria in drinking water distribution systems (DWDSs) is a major health concern, and our current understanding is mostly related to pathogenic species such as Legionella pneumophila and Mycobacterium avium but not to bacterial species closely related to them. In this study, genomic-based approaches were used to characterize pathogen-related species in relation to their abundance, diversity, potential pathogenicity, genetic exchange, and distribution across an urban drinking water system. Nine draft genomes recovered from 10 metagenomes were identified as Legionella (4 draft genomes), Mycobacterium (3 draft genomes), Parachlamydia (1 draft genome), and Leptospira (1 draft genome). The pathogenicity potential of these genomes was examined by the presence/absence of virulence machinery, including genes belonging to Type III, IV, and VII secretion systems and their effectors. Several virulence factors known to pathogenic species were detected with these retrieved draft genomes except the Leptospira-related genome. Identical clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins (CRISPR-Cas) genetic signatures were observed in two draft genomes recovered at different stages of the studied system, suggesting that the spacers in CRISPR-Cas could potentially be used as a biomarker in the monitoring of Legionella related strains at an evolutionary scale of several years across different drinking water production and distribution systems. Overall, metagenomics approach was an effective and complementary tool of culturing techniques to gain insights into the pathogenic characteristics and the CRISPR-Cas signatures of pathogen-related species in DWDSs. PMID:29097994

Genomic analysis of the type VI secretion systems in Pseudomonas spp.: novel clusters and putative effectors uncovered.

PubMed

Barret, Matthieu; Egan, Frank; Fargier, Emilie; Morrissey, John P; O'Gara, Fergal

2011-06-01

Bacteria encode multiple protein secretion systems that are crucial for interaction with the environment and with hosts. In recent years, attention has focused on type VI secretion systems (T6SSs), which are specialized transporters widely encoded in Proteobacteria. The myriad of processes associated with these secretion systems could be explained by subclasses of T6SS, each involved in specialized functions. To assess diversity and predict function associated with different T6SSs, comparative genomic analysis of 34 Pseudomonas genomes was performed. This identified 70 T6SSs, with at least one locus in every strain, except for Pseudomonas stutzeri A1501. By comparing 11 core genes of the T6SS, it was possible to identify five main Pseudomonas phylogenetic clusters, with strains typically carrying T6SSs from more than one clade. In addition, most strains encode additional vgrG and hcp genes, which encode extracellular structural components of the secretion apparatus. Using a combination of phylogenetic and meta-analysis of transcriptome datasets it was possible to associate specific subsets of VgrG and Hcp proteins with each Pseudomonas T6SS clade. Moreover, a closer examination of the genomic context of vgrG genes in multiple strains highlights a number of additional genes associated with these regions. It is proposed that these genes may play a role in secretion or alternatively could be new T6S effectors.

YscU/FlhB of Yersinia pseudotuberculosis Harbors a C-terminal Type III Secretion Signal*

PubMed Central

Login, Frédéric H.; Wolf-Watz, Hans

2015-01-01

All type III secretion systems (T3SS) harbor a member of the YscU/FlhB family of proteins that is characterized by an auto-proteolytic process that occurs at a conserved cytoplasmic NPTH motif. We have previously demonstrated that YscUCC, the C-terminal peptide generated by auto-proteolysis of Yersinia pseudotuberculosis YscU, is secreted by the T3SS when bacteria are grown in Ca2+-depleted medium at 37 °C. Here, we investigated the secretion of this early T3S-substrate and showed that YscUCC encompasses a specific C-terminal T3S signal within the 15 last residues (U15). U15 promoted C-terminal secretion of reporter proteins like GST and YopE lacking its native secretion signal. Similar to the “classical” N-terminal secretion signal, U15 interacted with the ATPase YscN. Although U15 is critical for YscUCC secretion, deletion of the C-terminal secretion signal of YscUCC did neither affect Yop secretion nor Yop translocation. However, these deletions resulted in increased secretion of YscF, the needle subunit. Thus, these results suggest that YscU via its C-terminal secretion signal is involved in regulation of the YscF secretion. PMID:26338709

The Ruler Protein EscP of the Enteropathogenic Escherichia coli Type III Secretion System Is Involved in Calcium Sensing and Secretion Hierarchy Regulation by Interacting with the Gatekeeper Protein SepL

PubMed Central

Shaulov, Lihi; Gershberg, Jenia; Deng, Wanyin; Finlay, B. Brett

2017-01-01

ABSTRACT The type III secretion system (T3SS) is a multiprotein complex that plays a central role in the virulence of many Gram-negative bacterial pathogens. To ensure that effector proteins are efficiently translocated into the host cell, bacteria must be able to sense their contact with the host cell. In this study, we found that EscP, which was previously shown to function as the ruler protein of the enteropathogenic Escherichia coli T3SS, is also involved in the switch from the secretion of translocator proteins to the secretion of effector proteins. In addition, we demonstrated that EscP can interact with the gatekeeper protein SepL and that the EscP-SepL complex dissociates upon a calcium concentration drop. We suggest a model in which bacterial contact with the host cell is accompanied by a drop in the calcium concentration that causes SepL-EscP complex dissociation and triggers the secretion of effector proteins. PMID:28049143

Label-Free Optofluidic Nanobiosensor Enables Real-Time Analysis of Single-Cell Cytokine Secretion.

PubMed

Li, Xiaokang; Soler, Maria; Szydzik, Crispin; Khoshmanesh, Khashayar; Schmidt, Julien; Coukos, George; Mitchell, Arnan; Altug, Hatice

2018-06-01

Single-cell analysis of cytokine secretion is essential to understand the heterogeneity of cellular functionalities and develop novel therapies for multiple diseases. Unraveling the dynamic secretion process at single-cell resolution reveals the real-time functional status of individual cells. Fluorescent and colorimetric-based methodologies require tedious molecular labeling that brings inevitable interferences with cell integrity and compromises the temporal resolution. An innovative label-free optofluidic nanoplasmonic biosensor is introduced for single-cell analysis in real time. The nanobiosensor incorporates a novel design of a multifunctional microfluidic system with small volume microchamber and regulation channels for reliable monitoring of cytokine secretion from individual cells for hours. Different interleukin-2 secretion profiles are detected and distinguished from single lymphoma cells. The sensor configuration combined with optical spectroscopic imaging further allows us to determine the spatial single-cell secretion fingerprints in real time. This new biosensor system is anticipated to be a powerful tool to characterize single-cell signaling for basic and clinical research. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

45 CFR 310.20 - What are the conditions for funding the installation, operation, maintenance and enhancement of...

Code of Federal Regulations, 2010 CFR

2010-10-01

... installation, operation, maintenance and enhancement of Computerized Tribal IV-D Systems and Office Automation... HEALTH AND HUMAN SERVICES COMPUTERIZED TRIBAL IV-D SYSTEMS AND OFFICE AUTOMATION Funding for Computerized Tribal IV-D Systems and Office Automation § 310.20 What are the conditions for funding the installation...

45 CFR 310.35 - Under what circumstances would emergency FFP be available for Computerized Tribal IV-D Systems?

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 2 2010-10-01 2010-10-01 false Under what circumstances would emergency FFP be... AND OFFICE AUTOMATION Funding for Computerized Tribal IV-D Systems and Office Automation § 310.35 Under what circumstances would emergency FFP be available for Computerized Tribal IV-D Systems? (a...

Mutations in ppe38 block PE_PGRS secretion and increase virulence of Mycobacterium tuberculosis.

PubMed

Ates, Louis S; Dippenaar, Anzaan; Ummels, Roy; Piersma, Sander R; van der Woude, Aniek D; van der Kuij, Kim; Le Chevalier, Fabien; Mata-Espinosa, Dulce; Barrios-Payán, Jorge; Marquina-Castillo, Brenda; Guapillo, Carolina; Jiménez, Connie R; Pain, Arnab; Houben, Edith N G; Warren, Robin M; Brosch, Roland; Hernández-Pando, Rogelio; Bitter, Wilbert

2018-02-01

Mycobacterium tuberculosis requires a large number of secreted and exported proteins for its virulence, immune modulation and nutrient uptake. Most of these proteins are transported by the different type VII secretion systems 1,2 . The most recently evolved type VII secretion system, ESX-5, secretes dozens of substrates belonging to the PE and PPE families, which are named for conserved proline and glutamic acid residues close to the amino terminus 3,4 . However, the role of these proteins remains largely elusive 1 . Here, we show that mutations of ppe38 completely block the secretion of two large subsets of ESX-5 substrates, that is, PPE-MPTR and PE_PGRS, together comprising >80 proteins. Importantly, hypervirulent clinical M. tuberculosis strains of the Beijing lineage have such a mutation and a concomitant loss of secretion 5 . Restoration of PPE38-dependent secretion partially reverted the hypervirulence phenotype of a Beijing strain, and deletion of ppe38 in moderately virulent M. tuberculosis increased virulence. This indicates that these ESX-5 substrates have an important role in virulence attenuation. Phylogenetic analysis revealed that deletion of ppe38 occurred at the branching point of the 'modern' Beijing sublineage and is shared by Beijing outbreak strains worldwide, suggesting that this deletion may have contributed to their success and global distribution 6,7 .

Do growth hormone-releasing peptides act as ghrelin secretagogues?

PubMed

Ahnfelt-Rønne, I; Nowak, J; Olsen, U B

2001-02-01

NN703 is an orally active and selective growth hormone secretagogue (GHS) that was derived from growth hormone-releasing peptide-1(GHRP-1) via ipamorelin by a peptidomimetic approach and has now entered into phase II clinical trials. When the disposition in rats of NN703 and GHRP-6 was studied using whole-body autoradiography following administration of an iv dose of radiolabeled material, we found that a substantial amount of these secretagogues accumulate in the glandular part of the stomach. Because this is the site of synthesis and secretion of ghrelin, the endogenous GHS, we investigated the effect of resection of the gastrointestinal (GI) tract on growth hormone (GH) release induced by GHRP-6. This procedure significantly attenuated the GH secretion response by 60-70%. By contrast, the effect of GH-releasing hormone on GH release was not inhibited. The binding of GHRPs to the glandular part of the stomach and the blunted GH response to GHRP-6 following resection of the GI tract suggest a role for ghrelin as a mediator of part of the GH-releasing effect of GHRPs.

Profiling of acarviostatin family secondary metabolites secreted by Streptomyces coelicoflavus ZG0656 using ultraperformance liquid chromatography coupled with electrospray ionization mass spectrometry.

PubMed

Geng, Peng; Meng, Xiansheng; Bai, Gang; Luo, Guoan

2008-10-01

Profiling of acarviostatin family secondary metabolites secreted by Streptomyces coelicoflavus ZG0656 was performed by means of a rapid and facile procedure using ultraperformance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC/ESI-MS). The acarviostatins were separated on a C18 UPLC column with a series of acetonitrile-aqueous ammonia gradients. The target homologues were detected using the multiple reaction monitoring mode, and the chemical structures were confirmed by analyzing the diagnostic fragment ions in their MS/MS spectra. All six known reference acarviostatins (I03, II03, II13, II23, III03, IV03) were thus identified. In addition, at least 74 acarviostatin homologues, including 65 novel compounds, were characterized. Some of the features of the novel structures included having up to five acarviosine moieties, an acarviosine moiety at the reducing terminus, or an incomplete acarviosine moiety at the nonreducing terminus. This type of investigation may be useful for researchers who study secondary metabolomics in microorganisms and plants, especially those who perform metabolic profiling of aminooligosaccharides and other natural products with similar structures.

Structural changes of oviduct of freshwater shrimp, Macrobrachium nipponense (Decapoda, Palaemonidae), during spawning*

PubMed Central

Lu, Jian-ping; Zhang, Xiao-hui; Yu, Xiao-yun

2006-01-01

The structural change of the oviduct of freshwater shrimp (Macrobrachium nipponense) during spawning was examined by electron microscopy. The oviduct wall structural characteristics seem to be influenced significantly by the spawning process. Before the parturition and ovulation, two types of epithelial cells (types I and II) are found in the epithelium. The free surfaces of type I and type II cells have very dense long microvilli. Under the type I and type II cells, are a relatively thick layer of secreting material and a layer of mostly dead cells. After ovulation, two other types of epithelial cells (types III and IV) are found in the oviduct wall epithelium. The free surface of type III cells only has short microvilli scattered on the surface. The thick layer with secreting material and the dead cell layer disappeared at this stage. In some type III cells, the leaking out of cytoplasm from broken cell membrane led to the death of these type III cells. The transformation of all four types of epithelial cells was in the order: IV→I→II→III. PMID:16365928

Endogenous opioids inhibit oxytocin release during nicotine-stimulated secretion of vasopressin in man.

PubMed

Seckl, J R; Johnson, M; Shakespear, C; Lightman, S L

1988-05-01

The effects of the opioid antagonist naloxone on the vasopressin (AVP) and oxytocin (OT) responses to nicotine were studied in male non-smokers (21-30 years old). Either saline (n = 6) or naloxone (4 mg bolus + 6 mg/h, n = 6) was infused i.v. during the study. After 60 min infusion the subjects smoked one high-nicotine content cigarette. Naloxone infusion for 60 min did not alter basal plasma AVP or OT levels. Smoking led to a significant rise in plasma vasopressin in both saline and naloxone-infused subjects (P less than 0.05). There was no significant difference in the plasma AVP response to smoking between the two groups. Saline-infused subjects did not show any change in plasma OT in response to smoking. Naloxone infusion was associated with a significant rise in OT from 1.3 +/- 0.1 pmol/l to 4.3 +/- 2.4 pmol/l 5 min after smoking (P less than 0.05). We conclude that there is endogenous opioid-mediated inhibition of OT which prevents its release when AVP is secreted in response to nicotine in man.

Mortality Prediction Using Acute Physiology and Chronic Health Evaluation II and Acute Physiology and Chronic Health Evaluation IV Scoring Systems: Is There a Difference?

PubMed Central

Venkataraman, Ramesh; Gopichandran, Vijayaprasad; Ranganathan, Lakshmi; Rajagopal, Senthilkumar; Abraham, Babu K; Ramakrishnan, Nagarajan

2018-01-01

Background: Mortality prediction in the Intensive Care Unit (ICU) setting is complex, and there are several scoring systems utilized for this process. The Acute Physiology and Chronic Health Evaluation (APACHE) II has been the most widely used scoring system; although, the more recent APACHE IV is considered an updated and advanced prediction model. However, these two systems may not give similar mortality predictions. Objectives: The aim of this study is to compare the mortality prediction ability of APACHE II and APACHE IV scoring systems among patients admitted to a tertiary care ICU. Methods: In this prospective longitudinal observational study, APACHE II and APACHE IV scores of ICU patients were computed using an online calculator. The outcome of the ICU admissions for all the patients was collected as discharged or deceased. The data were analyzed to compare the discrimination and calibration of the mortality prediction ability of the two scores. Results: Out of the 1670 patients' data analyzed, the area under the receiver operating characteristic of APACHE II score was 0.906 (95% confidence interval [CI] – 0.890–0.992), and APACHE IV score was 0.881 (95% CI – 0.862–0.890). The mean predicted mortality rate of the study population as given by the APACHE II scoring system was 44.8 ± 26.7 and as given by APACHE IV scoring system was 29.1 ± 28.5. The observed mortality rate was 22.4%. Conclusions: The APACHE II and IV scoring systems have comparable discrimination ability, but the calibration of APACHE IV seems to be better than that of APACHE II. There is a need to recalibrate the scales with weights derived from the Indian population. PMID:29910542

Mortality Prediction Using Acute Physiology and Chronic Health Evaluation II and Acute Physiology and Chronic Health Evaluation IV Scoring Systems: Is There a Difference?

PubMed

Venkataraman, Ramesh; Gopichandran, Vijayaprasad; Ranganathan, Lakshmi; Rajagopal, Senthilkumar; Abraham, Babu K; Ramakrishnan, Nagarajan

2018-05-01

Mortality prediction in the Intensive Care Unit (ICU) setting is complex, and there are several scoring systems utilized for this process. The Acute Physiology and Chronic Health Evaluation (APACHE) II has been the most widely used scoring system; although, the more recent APACHE IV is considered an updated and advanced prediction model. However, these two systems may not give similar mortality predictions. The aim of this study is to compare the mortality prediction ability of APACHE II and APACHE IV scoring systems among patients admitted to a tertiary care ICU. In this prospective longitudinal observational study, APACHE II and APACHE IV scores of ICU patients were computed using an online calculator. The outcome of the ICU admissions for all the patients was collected as discharged or deceased. The data were analyzed to compare the discrimination and calibration of the mortality prediction ability of the two scores. Out of the 1670 patients' data analyzed, the area under the receiver operating characteristic of APACHE II score was 0.906 (95% confidence interval [CI] - 0.890-0.992), and APACHE IV score was 0.881 (95% CI - 0.862-0.890). The mean predicted mortality rate of the study population as given by the APACHE II scoring system was 44.8 ± 26.7 and as given by APACHE IV scoring system was 29.1 ± 28.5. The observed mortality rate was 22.4%. The APACHE II and IV scoring systems have comparable discrimination ability, but the calibration of APACHE IV seems to be better than that of APACHE II. There is a need to recalibrate the scales with weights derived from the Indian population.

Psychosis, central hyperventilation and inappropriate secretion of antidiuretic hormone in systemic lupus erythematosus

PubMed Central

Decaux, G.; Unger, J.; Marneffe, C.

1981-01-01

A case of systemic lupus erythematosus with reversible psychosis and hyperventilation related to hyponatraemia secondary to a syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is presented. The SIADH was treated successfully by oral urea for more than 8 months. PMID:7339606

Proteins Exported via the PrsD-PrsE Type I Secretion System and the Acidic Exopolysaccharide Are Involved in Biofilm Formation by Rhizobium leguminosarum

PubMed Central

Russo, Daniela M.; Williams, Alan; Edwards, Anne; Posadas, Diana M.; Finnie, Christine; Dankert, Marcelo; Downie, J. Allan; Zorreguieta, Angeles

2006-01-01

The type I protein secretion system of Rhizobium leguminosarum bv. viciae encoded by the prsD and prsE genes is responsible for secretion of the exopolysaccharide (EPS)-glycanases PlyA and PlyB. The formation of a ring of biofilm on the surface of the glass in shaken cultures by both the prsD and prsE secretion mutants was greatly affected. Confocal laser scanning microscopy analysis of green-fluorescent-protein-labeled bacteria showed that during growth in minimal medium, R. leguminosarum wild type developed microcolonies, which progress to a characteristic three-dimensional biofilm structure. However, the prsD and prsE secretion mutants were able to form only an immature biofilm structure. A mutant disrupted in the EPS-glycanase plyB gene showed altered timing of biofilm formation, and its structure was atypical. A mutation in an essential gene for EPS synthesis (pssA) or deletion of several other pss genes involved in EPS synthesis completely abolished the ability of R. leguminosarum to develop a biofilm. Extracellular complementation studies of mixed bacterial cultures confirmed the role of the EPS and the modulation of the biofilm structure by the PrsD-PrsE secreted proteins. Protein analysis identified several additional proteins secreted by the PrsD-PrsE secretion system, and N-terminal sequencing revealed peptides homologous to the N termini of proteins from the Rap family (Rhizobium adhering proteins), which could have roles in cellular adhesion in R. leguminosarum. We propose a model for R. leguminosarum in which synthesis of the EPS leads the formation of a biofilm and several PrsD-PrsE secreted proteins are involved in different aspects of biofilm maturation, such as modulation of the EPS length or mediating attachment between bacteria. PMID:16740954

An integrated microfluidic chip system for single-cell secretion profiling of rare circulating tumor cells.

PubMed

Deng, Yuliang; Zhang, Yu; Sun, Shuai; Wang, Zhihua; Wang, Minjiao; Yu, Beiqin; Czajkowsky, Daniel M; Liu, Bingya; Li, Yan; Wei, Wei; Shi, Qihui

2014-12-16

Genetic and transcriptional profiling, as well as surface marker identification of single circulating tumor cells (CTCs) have been demonstrated. However, quantitatively profiling of functional proteins at single CTC resolution has not yet been achieved, owing to the limited purity of the isolated CTC populations and a lack of single-cell proteomic approaches to handle and analyze rare CTCs. Here, we develop an integrated microfluidic system specifically designed for streamlining isolation, purification and single-cell secretomic profiling of CTCs from whole blood. Key to this platform is the use of photocleavable ssDNA-encoded antibody conjugates to enable a highly purified CTC population with <75 'contaminated' blood cells. An enhanced poly-L-lysine barcode pattern is created on the single-cell barcode chip for efficient capture rare CTC cells in microchambers for subsequent secreted protein profiling. This system was extensively evaluated and optimized with EpCAM-positive HCT116 cells seeded into whole blood. Patient blood samples were employed to assess the utility of the system for isolation, purification and single-cell secretion profiling of CTCs. The CTCs present in patient blood samples exhibit highly heterogeneous secretion profile of IL-8 and VEGF. The numbers of secreting CTCs are found not in accordance with CTC enumeration based on immunostaining in the parallel experiments.

An Integrated Microfluidic Chip System for Single-Cell Secretion Profiling of Rare Circulating Tumor Cells

PubMed Central

Deng, Yuliang; Zhang, Yu; Sun, Shuai; Wang, Zhihua; Wang, Minjiao; Yu, Beiqin; Czajkowsky, Daniel M.; Liu, Bingya; Li, Yan; Wei, Wei; Shi, Qihui

2014-01-01

Genetic and transcriptional profiling, as well as surface marker identification of single circulating tumor cells (CTCs) have been demonstrated. However, quantitatively profiling of functional proteins at single CTC resolution has not yet been achieved, owing to the limited purity of the isolated CTC populations and a lack of single-cell proteomic approaches to handle and analyze rare CTCs. Here, we develop an integrated microfluidic system specifically designed for streamlining isolation, purification and single-cell secretomic profiling of CTCs from whole blood. Key to this platform is the use of photocleavable ssDNA-encoded antibody conjugates to enable a highly purified CTC population with <75 ‘contaminated' blood cells. An enhanced poly-L-lysine barcode pattern is created on the single-cell barcode chip for efficient capture rare CTC cells in microchambers for subsequent secreted protein profiling. This system was extensively evaluated and optimized with EpCAM-positive HCT116 cells seeded into whole blood. Patient blood samples were employed to assess the utility of the system for isolation, purification and single-cell secretion profiling of CTCs. The CTCs present in patient blood samples exhibit highly heterogeneous secretion profile of IL-8 and VEGF. The numbers of secreting CTCs are found not in accordance with CTC enumeration based on immunostaining in the parallel experiments. PMID:25511131

LcrQ and SycH function together at the Ysc type III secretion system in Yersinia pestis to impose a hierarchy of secretion.

PubMed

Wulff-Strobel, Christine R; Williams, Andrew W; Straley, Susan C

2002-01-01

LcrQ is a regulatory protein unique to Yersinia. Previous study in Yersinia pseudotuberculosis and Yersinia enterocolitica prompted the model in which LcrQ negatively regulates the expression of a set of virulence proteins called Yops, and its secretion upon activation of the Yop secretion (Ysc) type III secretion system permits full induction of Yops expression. In this study, we tested the hypothesis that LcrQ's effects on Yops expression might be indirect. Excess LcrQ was found to exert an inhibitory effect specifically at the level of Yops secretion, independent of production, and a normal inner Ysc gate protein LcrG was required for this activity. However, overexpression of LcrQ did not prevent YopH secretion, suggesting that LcrQ's effects at the Ysc discriminate among the Yops. We tested this idea by determining the effects of deletion or overexpression of LcrQ, YopH and their common chaperone SycH on early Yop secretion through the Ysc. Together, our findings indicated that LcrQ is not a negative regulator directly, but it acts in partnership with SycH at the Ysc gate to control the entry of a set of Ysc secretion substrates. A hierarchy of YopH secretion before YopE appears to be imposed by SycH in conjunction with both LcrQ and YopH. LcrQ and SycH in addition influenced the deployment of LcrV, a component of the Yops delivery mechanism. Accordingly, LcrQ appears to be a central player in determining the substrate specificity of the Ysc.

Interactions between the Central Nervous System and Pancreatic Islet Secretions: A Historical Perspective

ERIC Educational Resources Information Center

Begg, Denovan P.; Woods, Stephen C.

2013-01-01

The endocrine pancreas is richly innervated with sympathetic and parasympathetic projections from the brain. In the mid-20th century, it was established that alpha-adrenergic activation inhibits, whereas cholinergic stimulation promotes, insulin secretion; this demonstrated the importance of the sympathetic and parasympathetic systems in…

Multicellular Self-Organization of P. aeruginosa due to Interactions with Secreted Trails.

PubMed

Gelimson, Anatolij; Zhao, Kun; Lee, Calvin K; Kranz, W Till; Wong, Gerard C L; Golestanian, Ramin

2016-10-21

Guided movement in response to slowly diffusing polymeric trails provides a unique mechanism for self-organization of some microorganisms. To elucidate how this signaling route leads to microcolony formation, we experimentally probe the trajectory and orientation of Pseudomonas aeruginosa that propel themselves on a surface using type IV pili motility appendages, which preferentially attach to deposited exopolysaccharides. We construct a stochastic model by analyzing single-bacterium trajectories and show that the resulting theoretical prediction for the many-body behavior of the bacteria is in quantitative agreement with our experimental characterization of how cells explore the surface via a power-law strategy.

A type IV translocated Legionella cysteine phytase counteracts intracellular growth restriction by phytate.

PubMed

Weber, Stephen; Stirnimann, Christian U; Wieser, Mara; Frey, Daniel; Meier, Roger; Engelhardt, Sabrina; Li, Xiaodan; Capitani, Guido; Kammerer, Richard A; Hilbi, Hubert

2014-12-05

The causative agent of Legionnaires' pneumonia, Legionella pneumophila, colonizes diverse environmental niches, including biofilms, plant material, and protozoa. In these habitats, myo-inositol hexakisphosphate (phytate) is prevalent and used as a phosphate storage compound or as a siderophore. L. pneumophila replicates in protozoa and mammalian phagocytes within a unique "Legionella-containing vacuole." The bacteria govern host cell interactions through the Icm/Dot type IV secretion system (T4SS) and ∼300 different "effector" proteins. Here we characterize a hitherto unrecognized Icm/Dot substrate, LppA, as a phytate phosphatase (phytase). Phytase activity of recombinant LppA required catalytically essential cysteine (Cys(231)) and arginine (Arg(237)) residues. The structure of LppA at 1.4 Å resolution revealed a mainly α-helical globular protein stabilized by four antiparallel β-sheets that binds two phosphate moieties. The phosphates localize to a P-loop active site characteristic of dual specificity phosphatases or to a non-catalytic site, respectively. Phytate reversibly abolished growth of L. pneumophila in broth, and growth inhibition was relieved by overproduction of LppA or by metal ion titration. L. pneumophila lacking lppA replicated less efficiently in phytate-loaded Acanthamoeba castellanii or Dictyostelium discoideum, and the intracellular growth defect was complemented by the phytase gene. These findings identify the chelator phytate as an intracellular bacteriostatic component of cell-autonomous host immunity and reveal a T4SS-translocated L. pneumophila phytase that counteracts intracellular bacterial growth restriction by phytate. Thus, bacterial phytases might represent therapeutic targets to combat intracellular pathogens. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Host-Associated Genomic Features of the Novel Uncultured Intracellular Pathogen Ca. Ichthyocystis Revealed by Direct Sequencing of Epitheliocysts

PubMed Central

Qi, Weihong; Vaughan, Lloyd; Katharios, Pantelis; Schlapbach, Ralph; Seth-Smith, Helena M.B.

2016-01-01

Advances in single-cell and mini-metagenome sequencing have enabled important investigations into uncultured bacteria. In this study, we applied the mini-metagenome sequencing method to assemble genome drafts of the uncultured causative agents of epitheliocystis, an emerging infectious disease in the Mediterranean aquaculture species gilthead seabream. We sequenced multiple cyst samples and constructed 11 genome drafts from a novel beta-proteobacterial lineage, Candidatus Ichthyocystis. The draft genomes demonstrate features typical of pathogenic bacteria with an obligate intracellular lifestyle: a reduced genome of up to 2.6 Mb, reduced G + C content, and reduced metabolic capacity. Reconstruction of metabolic pathways reveals that Ca. Ichthyocystis genomes lack all amino acid synthesis pathways, compelling them to scavenge from the fish host. All genomes encode type II, III, and IV secretion systems, a large repertoire of predicted effectors, and a type IV pilus. These are all considered to be virulence factors, required for adherence, invasion, and host manipulation. However, no evidence of lipopolysaccharide synthesis could be found. Beyond the core functions shared within the genus, alignments showed distinction into different species, characterized by alternative large gene families. These comprise up to a third of each genome, appear to have arisen through duplication and diversification, encode many effector proteins, and are seemingly critical for virulence. Thus, Ca. Ichthyocystis represents a novel obligatory intracellular pathogenic beta-proteobacterial lineage. The methods used: mini-metagenome analysis and manual annotation, have generated important insights into the lifestyle and evolution of the novel, uncultured pathogens, elucidating many putative virulence factors including an unprecedented array of novel gene families. PMID:27190004

Hard-to-cook bean (Phaseolus vulgaris L.) proteins hydrolyzed by alcalase and bromelain produced bioactive peptide fractions that inhibit targets of type-2 diabetes and oxidative stress.

PubMed

Oseguera-Toledo, Miguel E; Gonzalez de Mejia, Elvira; Amaya-Llano, Silvia L

2015-10-01

The objective was to evaluate the effect of bioactive peptide fractions from de-hulled hard-to-cook (HTC) bean on enzyme targets of type-2 diabetes and oxidative stress. Protein isolates from Pinto Durango and Negro 8025 beans were hydrolyzed (120min) with either alcalase® or bromelain and separated into five peptide fractions (<1, 1-3.5, 3.5-5, 5-10, and >10kDa) using an ultrafiltration membrane system. The <1kDa pinto Durango-bromelain fraction showed the best inhibition of α-amylase (49.9±1.4%), and the <1kDa pinto Durango-alcalase fraction inhibited both, α-glucosidase (76.4±0.5%), and dipeptidyl peptidase-IV (DPP-IV, 55.3±1.6%). Peptides LLSL, QQEG and NEGEAH were present in the most potent fractions. Hydrolysates and peptide fractions showed antioxidant capacity (ORAC: 159.6±2.9 to 932.6±1.1mmolTE/g) and nitric oxide inhibition (57.5±0.9 to 68.3±4.2%). Hydrolysates and fractions <1 and 1-3kDa were able to increase glucose-stimulated insulin secretion from iNS-1E cells up to 57% compared to glucose control. Hydrolysates from HTC beans inhibited enzymes related to diabetes management, being the smallest peptides (<1kDa) the most potent. HTC bean could be a source of protein to produce bioactive peptides with potential antidiabetic properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Secretion profiles of fungi as potential tools for metal ecotoxicity assessment: a study of enzymatic system in Trametes versicolor.

PubMed

Lebrun, Jérémie D; Demont-Caulet, Nathalie; Cheviron, Nathalie; Laval, Karine; Trinsoutrot-Gattin, Isabelle; Mougin, Christian

2011-01-01

The relationship between the expression of extracellular enzymatic system and a metal stress is scarce in fungi, hence limiting the possible use of secretion profiles as tools for metal ecotoxicity assessment. In the present study, we investigated the effect of Zn, Cu, Pb and Cd, tested alone or in equimolar cocktail, on the secretion profiles at enzymatic and protein levels in Trametesversicolor. For that purpose, extracellular hydrolases (acid phosphatase, β-glucosidase, β-galactosidase and N-acetyl-β-glucosaminidase) and ligninolytic oxidases (laccase, Mn-peroxidase) were monitored in liquid cultures. Fungal secretome was analyzed by electrophoresis and laccase secretion was characterized by western-blot and mass spectrometry analyses. Our results showed that all hydrolase activities were inhibited by the metals tested alone or in cocktail, whereas oxidase activities were specifically stimulated by Cu, Cd and metal cocktail. At protein level, metal exposure modified the electrophoretic profiles of fungal secretome and affected the diversity of secreted proteins. Two laccase isoenzymes, LacA and LacB, identified by mass spectrometry were differentially glycosylated according to the metal exposure. The amount of secreted LacA and LacB was strongly correlated with the stimulation of laccase activity by Cu, Cd and metal cocktail. These modifications of extracellular enzymatic system suggest that fungal oxidases could be used as biomarkers of metal exposure. Copyright © 2010 Elsevier Ltd. All rights reserved.

Short children with familial short stature show enhancement of somatotroph secretion but normal IGF-I levels.

PubMed

Bellone, S; Corneli, G; Bellone, J; Baffoni, C; Rovere, S; de Sanctis, C; Bona, G; Ghigo, E; Aimaretti, G

2002-05-01

The aim of the present study was to evaluate the GH status in children with familial, idiopathic short stature (FSS). To this goal we evaluated the GH response to GHRH (1 microg/kg iv) + arginine (ARG) (0.5 g/kg iv) test which is one of the most potent and reproducible provocative tests of somatotroph secretion, in 67 children with FSS [50 boys and 17 girls, age 10.8+/-0.4 yr, pubertal stages I-III, height between -3.6 and -1.6 standard deviation score (SDS), target height <10 degrees centile, normality of both spontaneous and stimulated GH secretion as well as of IGF-I levels]. The results in FSS were compared with those in groups of children of normal height (NHC) (42 NHC, 35 boys and 7 girls, age 12.0+/-0.5 yr, pubertal stages I-III, height between -1.3 and 1.4 SDS, height velocity standard deviation score (HVSDS)>25 degrees centile, GH peak >20 microg/l after GHRH+ARG test, mean GH concentration [mGHc]>3 microg/l) and children with organic GH deficiency (GHD) (38 GHD, 29 boys and 9 girls, age 11.2+/-3.7 yr, pubertal stages I-III, height between -5.7 and -1.3 SDS, GH peak <20 microg/l after GHRH +ARG test, mGHc <3 mg/l). Basal IGF-I levels and mGHc were also evaluated in each group over 8 nocturnal hours. IGF-I levels in FSS (209.2+/-15.6 microg/l) were similar to those in NHC (237.2+/-17.2 microg/l) and both were higher (p<0.0001) than those in GHD (72.0+/-4.0 microg/l). The GH response to GHRH +ARG test in FSS (peak: 66.4+/-5.6 microg/l) was very marked and higher (p<0.01) than that in NHC (53.3+/-4.5 microg/l) which, in turn, was higher (p<0.01) than in GHD (8.2+/-0.8 microg/l). Similarly, the mGHc in FSS was higher than in NHC (6.7+/-0.5 microg/l vs 5.1+/-0.7 microg/l, p<0.05) which, in turn, was higher than in GHD (1.5+/-0.2 microg/l, p<0.0001). In conclusion, our present study demonstrates that short children with FSS show enhancement of both basal and stimulated GH secretion but normal IGF-I levels. These findings suggest that increased somatotroph function would be devoted to maintain normal IGF-I levels thus reflecting a slight impairment of peripheral GH sensitivity in FSS.

Organizational and technological correlates of nurses’ trust in a smart IV pump

PubMed Central

Montague, Enid; Asan, Onur; Chiou, Erin

2013-01-01

The aim of this study was to understand technology and system characteristics that contribute to nurses’ ratings of trust in a smart IV pump. Nurse’s trust in new technologies can influence how technologies are used. Trust in technology is defined as a person’s belief that a technology will not fail them. Potential outcomes of trust in technology are appropriate trust, over trust, distrust, and mistrust. Trust in technology is also related to several use specific outcomes, including appropriate use and inappropriate use such as over reliance, disuse or rejection, or misuse. Understanding trust in relation to outcomes can contribute to designs that facilitate appropriate trust in new technologies. A survey was completed by 391 nurses a year after the implementation of a new smart IV pump. The survey assessed trust in the IV pump and other elements of the sociotechnical system, individual characteristics, technology characteristics and organizational characteristics. Results show perceptions of usefulness, safety, ease of use and usability are related to ratings of trust in smart IV pumps. Other work system factors such as perception of work environment, age, experience, quality of work, and perception of work performance are also related to ratings of trust. Nurses’ trust in smart IV pumps is influenced by both characteristics of the technology and the sociotechnical system. Findings from this research have implications for the design of future smart IV pumps and health systems. Recommendations for appropriately trustworthy smart IV pumps are discussed. Findings also have implications for how trust in health technologies can be measured and conceptualized in complex sociotechnical systems. PMID:23321482

Gene and transcript abundances of bacterial type III secretion systems from the rumen microbiome are correlated with methane yield in sheep.

PubMed

Kamke, Janine; Soni, Priya; Li, Yang; Ganesh, Siva; Kelly, William J; Leahy, Sinead C; Shi, Weibing; Froula, Jeff; Rubin, Edward M; Attwood, Graeme T

2017-08-08

Ruminants are important contributors to global methane emissions via microbial fermentation in their reticulo-rumens. This study is part of a larger program, characterising the rumen microbiomes of sheep which vary naturally in methane yield (g CH 4 /kg DM/day) and aims to define differences in microbial communities, and in gene and transcript abundances that can explain the animal methane phenotype. Rumen microbiome metagenomic and metatranscriptomic data were analysed by Gene Set Enrichment, sparse partial least squares regression and the Wilcoxon Rank Sum test to estimate correlations between specific KEGG bacterial pathways/genes and high methane yield in sheep. KEGG genes enriched in high methane yield sheep were reassembled from raw reads and existing contigs and analysed by MEGAN to predict their phylogenetic origin. Protein coding sequences from Succinivibrio dextrinosolvens strains were analysed using Effective DB to predict bacterial type III secreted proteins. The effect of S. dextrinosolvens strain H5 growth on methane formation by rumen methanogens was explored using co-cultures. Detailed analysis of the rumen microbiomes of high methane yield sheep shows that gene and transcript abundances of bacterial type III secretion system genes are positively correlated with methane yield in sheep. Most of the bacterial type III secretion system genes could not be assigned to a particular bacterial group, but several genes were affiliated with the genus Succinivibrio, and searches of bacterial genome sequences found that strains of S. dextrinosolvens were part of a small group of rumen bacteria that encode this type of secretion system. In co-culture experiments, S. dextrinosolvens strain H5 showed a growth-enhancing effect on a methanogen belonging to the order Methanomassiliicoccales, and inhibition of a representative of the Methanobrevibacter gottschalkii clade. This is the first report of bacterial type III secretion system genes being associated with high methane emissions in ruminants, and identifies these secretions systems as potential new targets for methane mitigation research. The effects of S. dextrinosolvens on the growth of rumen methanogens in co-cultures indicate that bacteria-methanogen interactions are important modulators of methane production in ruminant animals.

Structural insights into the roles of the IcmS-IcmW complex in the type IVb secretion system of Legionella pneumophila.

PubMed

Xu, Jianpo; Xu, Dandan; Wan, Muyang; Yin, Li; Wang, Xiaofei; Wu, Lijie; Liu, Yanhua; Liu, Xiaoyun; Zhou, Yan; Zhu, Yongqun

2017-12-19

The type IVb secretion system (T4BSS) of Legionella pneumophila is a multiple-component apparatus that delivers ∼300 virulent effector proteins into host cells. The injected effectors modulate host cellular processes to promote bacterial infection and proliferation. IcmS and IcmW are two conserved small, acidic adaptor proteins that form a binary complex to interact with many effectors and facilitate their translocation. IcmS and IcmW can also interact with DotL, an ATPase of the type IV coupling protein complex (T4CP). However, how IcmS-IcmW recognizes effectors, and what the roles of IcmS-IcmW are in T4BSSs are unclear. In this study, we found that IcmS and IcmW form a 1:1 heterodimeric complex to bind effector substrates. Both IcmS and IcmW adopt new structural folds and have no structural similarities with known effector chaperones. IcmS has a compact global structure with an α/β fold, while IcmW adopts a fully α-folded, relatively loose architecture. IcmS stabilizes IcmW by binding to its two C-terminal α-helices. Photocrosslinking assays revealed that the IcmS-IcmW complex binds its cognate effectors via an extended hydrophobic surface, which can also interact with the C terminus of DotL. A crystal structure of the DotL-IcmS-IcmW complex reveals extensive and highly stable interactions between DotL and IcmS-IcmW. Moreover, IcmS-IcmW recruits LvgA to DotL and assembles a unique T4CP. These data suggest that IcmS-IcmW also functions as an inseparable integral component of the DotL-T4CP complex in the bacterial inner membrane. This study provides molecular insights into the dual roles of the IcmS-IcmW complex in T4BSSs.

YscU/FlhB of Yersinia pseudotuberculosis Harbors a C-terminal Type III Secretion Signal.

PubMed

Login, Frédéric H; Wolf-Watz, Hans

2015-10-23

All type III secretion systems (T3SS) harbor a member of the YscU/FlhB family of proteins that is characterized by an auto-proteolytic process that occurs at a conserved cytoplasmic NPTH motif. We have previously demonstrated that YscUCC, the C-terminal peptide generated by auto-proteolysis of Yersinia pseudotuberculosis YscU, is secreted by the T3SS when bacteria are grown in Ca(2+)-depleted medium at 37 °C. Here, we investigated the secretion of this early T3S-substrate and showed that YscUCC encompasses a specific C-terminal T3S signal within the 15 last residues (U15). U15 promoted C-terminal secretion of reporter proteins like GST and YopE lacking its native secretion signal. Similar to the "classical" N-terminal secretion signal, U15 interacted with the ATPase YscN. Although U15 is critical for YscUCC secretion, deletion of the C-terminal secretion signal of YscUCC did neither affect Yop secretion nor Yop translocation. However, these deletions resulted in increased secretion of YscF, the needle subunit. Thus, these results suggest that YscU via its C-terminal secretion signal is involved in regulation of the YscF secretion. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Acinetobacter baumannii Is Dependent on the Type II Secretion System and Its Substrate LipA for Lipid Utilization and In Vivo Fitness

PubMed Central

Johnson, Tanya L.; Waack, Ursula; Smith, Sara; Mobley, Harry

2015-01-01

ABSTRACT Gram-negative bacteria express a number of sophisticated secretion systems to transport virulence factors across the cell envelope, including the type II secretion (T2S) system. Genes for the T2S components GspC through GspN and PilD are conserved among isolates of Acinetobacter baumannii, an increasingly common nosocomial pathogen that is developing multidrug resistance at an alarming rate. In contrast to most species, however, the T2S genes are dispersed throughout the genome rather than linked into one or two operons. Despite this unique genetic organization, we show here that the A. baumannii T2S system is functional. Deletion of gspD or gspE in A. baumannii ATCC 17978 results in loss of secretion of LipA, a lipase that breaks down long-chain fatty acids. Due to a lack of extracellular lipase, the gspD mutant, the gspE mutant, and a lipA deletion strain are incapable of growth on long-chain fatty acids as a sole source of carbon, while their growth characteristics are indistinguishable from those of the wild-type strain in nutrient-rich broth. Genetic inactivation of the T2S system and its substrate, LipA, also has a negative impact on in vivo fitness in a neutropenic murine model for bacteremia. Both the gspD and lipA mutants are outcompeted by the wild-type strain as judged by their reduced numbers in spleen and liver following intravenous coinoculation. Collectively, our findings suggest that the T2S system plays a hitherto-unrecognized role in in vivo survival of A. baumannii by transporting a lipase that may contribute to fatty acid metabolism. IMPORTANCE Infections by multidrug-resistant Acinetobacter baumannii are a growing health concern worldwide, underscoring the need for a better understanding of the molecular mechanisms by which this pathogen causes disease. In this study, we demonstrated that A. baumannii expresses a functional type II secretion (T2S) system that is responsible for secretion of LipA, an extracellular lipase required for utilization of exogenously added lipids. The T2S system and the secreted lipase support in vivo colonization and thus contribute to the pathogenic potential of A. baumannii. PMID:26668261

Regulation of Protein Secretion Through Controlled Aggregation in the Endoplasmic Reticulum

NASA Astrophysics Data System (ADS)

Rivera, Victor M.; Wang, Xiurong; Wardwell, Scott; Courage, Nancy L.; Volchuk, Allen; Keenan, Terence; Holt, Dennis A.; Gilman, Michael; Orci, Lelio; Cerasoli, Frank; Rothman, James E.; Clackson, Tim

2000-02-01

A system for direct pharmacologic control of protein secretion was developed to allow rapid and pulsatile delivery of therapeutic proteins. A protein was engineered so that it accumulated as aggregates in the endoplasmic reticulum. Secretion was then stimulated by a synthetic small-molecule drug that induces protein disaggregation. Rapid and transient secretion of growth hormone and insulin was achieved in vitro and in vivo. A regulated pulse of insulin secretion resulted in a transient correction of serum glucose concentrations in a mouse model of hyperglycemia. This approach may make gene therapy a viable method for delivery of polypeptides that require rapid and regulated delivery.

Acanthamoeba and Dictyostelium as Cellular Models for Legionella Infection

PubMed Central

Swart, A. Leoni; Harrison, Christopher F.; Eichinger, Ludwig; Steinert, Michael; Hilbi, Hubert

2018-01-01

Environmental bacteria of the genus Legionella naturally parasitize free-living amoebae. Upon inhalation of bacteria-laden aerosols, the opportunistic pathogens grow intracellularly in alveolar macrophages and can cause a life-threatening pneumonia termed Legionnaires' disease. Intracellular replication in amoebae and macrophages takes place in a unique membrane-bound compartment, the Legionella-containing vacuole (LCV). LCV formation requires the bacterial Icm/Dot type IV secretion system, which translocates literally hundreds of “effector” proteins into host cells, where they modulate crucial cellular processes for the pathogen's benefit. The mechanism of LCV formation appears to be evolutionarily conserved, and therefore, amoebae are not only ecologically significant niches for Legionella spp., but also useful cellular models for eukaryotic phagocytes. In particular, Acanthamoeba castellanii and Dictyostelium discoideum emerged over the last years as versatile and powerful models. Using genetic, biochemical and cell biological approaches, molecular interactions between amoebae and Legionella pneumophila have recently been investigated in detail with a focus on the role of phosphoinositide lipids, small and large GTPases, autophagy components and the retromer complex, as well as on bacterial effectors targeting these host factors. PMID:29552544

Role of Helicobacter pylori virulence factor cytotoxin-associated gene A in gastric mucosa-associated lymphoid tissue lymphoma

PubMed Central

Wang, Hong-Ping; Zhu, Yong-Liang; Shao, Wei

2013-01-01

Helicobacter pylori (H. pylori) infection might initiate and contribute to the progression of lymphoma from gastric mucosa-associated lymphoid tissue (MALT). Increasing evidence shows that eradication of H. pylori with antibiotic therapy can lead to regression of gastric MALT lymphoma and can result in a 10-year sustained remission. The eradication of H. pylori is the standard care for patients with gastric MALT lymphoma. Cytotoxin-associated gene A (CagA) protein, one of the most extensively studied H. pylori virulence factors, is strongly associated with the gastric MALT lymphoma. CagA possesses polymorphisms according to its C-terminal structure and displays different functions among areas and races. After being translocated into B lymphocytes via type IV secretion system, CagA deregulates intracellular signaling pathways in both tyrosine phosphorylation-dependent and -independent manners and/or some other pathways, and thereby promotes lymphomagenesis. A variety of proteins including p53 and protein tyrosine phosphatases-2 are involved in the malignant transformation induced by CagA. Mucosal inflammation is the foundational mechanism underlying the occurrence and development of gastric MALT lymphoma. PMID:24363512

Characterization of a spontaneous avirulent mutant of Legionella pneumophila Serogroup 6: evidence of DotA and flagellin involvement in the loss of virulence.

PubMed

Scaturro, Maria; Meschini, Stefania; Arancia, Giuseppe; Stefano, Fontana; Ricci, Maria Luisa

2009-12-01

The pathogenesis of Legionella pneumophila mainly resides in its ability to inhibit the phagosome-lysosome fusion, which normally prevents the killing of the host cells. In order to characterize the molecular alterations that occurred in a spontaneous avirulent mutant of Legionella pneumophila serogroup 6, named Vir-, we investigated the ability of the mutant to adhere to and multiply in the WI26VA4 alveolar epithelial cell line and in human macrophages, when compared to its parental strain, Vir+. We also determined the colocalization of bacteria with LAMP-1 to gain an insight into the phagosome-lysosome fusion process. Additionally, we determined the flagellin expression and dotA nucleotide sequencing. We observed a lack of expression of flagellin and an in-frame mutation in the dotA. gene. The data obtained strongly suggest the loss of virulence of the mutant could probably be due to the absence of flagellin and the dysfunctional type IV secretion System, resulting from the DotA protein being severely compromised.

Transfer of DNA from Bacteria to Eukaryotes

PubMed Central

2016-01-01

ABSTRACT Historically, the members of the Agrobacterium genus have been considered the only bacterial species naturally able to transfer and integrate DNA into the genomes of their eukaryotic hosts. Yet, increasing evidence suggests that this ability to genetically transform eukaryotic host cells might be more widespread in the bacterial world. Indeed, analyses of accumulating genomic data reveal cases of horizontal gene transfer from bacteria to eukaryotes and suggest that it represents a significant force in adaptive evolution of eukaryotic species. Specifically, recent reports indicate that bacteria other than Agrobacterium, such as Bartonella henselae (a zoonotic pathogen), Rhizobium etli (a plant-symbiotic bacterium related to Agrobacterium), or even Escherichia coli, have the ability to genetically transform their host cells under laboratory conditions. This DNA transfer relies on type IV secretion systems (T4SSs), the molecular machines that transport macromolecules during conjugative plasmid transfer and also during transport of proteins and/or DNA to the eukaryotic recipient cells. In this review article, we explore the extent of possible transfer of genetic information from bacteria to eukaryotic cells as well as the evolutionary implications and potential applications of this transfer. PMID:27406565

[Metalloproteinases in meningoencephalitis].

PubMed

Pastuszka, Ewa; Pabin, Agata; Radkowski, Marek

2008-01-01

Meningoencephalitis remains a devastating disease with high morbidity and mortality. Despite advances in antibiotic treatment and critical care, mortality rate in bacterial meningoencephalitis is close to 25%. Moreover, neurological and neuropsychological sequelae emerge in up to 50% of survivors. Adverse outcome is significantly associated with events secondary to meningitis and damage of the blood-brain barrier. Several studies conducted on animals confirmed that matrix-metalloproteinases (MMP), a family of enzymes with major actions in the remodeling of exracellural matrix components facilitate this process which results in acute neurological complications. Gelatinases (MMP-2, MMP-9), the most complex family member, through degradation of gelatine and collagen IV play an important role in the pathogenesis of brain's inflamatory diseases (e.g. Guillian-Barre syndrom) and contribute to spreading the disease beyond the central nervous system. Infection (bacterial, viral or fungal) can lead to increased concentration and activity of metalloproteinases due to excessive enzyme's secretion or decrease in level of its natural inhibitors. A detailed analysis of those enzymes could help in developing new diagnostic and prognostic markers for meningoencephalitis and could facilitate new treatment approaches.

The secretory IgA system of lung secretions in chronic obstructive bronchitis: comparison of sputum with secretions obtained during fibreoptic bronchoscopy.

PubMed Central

Wiggins, J; Hill, S L; Stockley, R A

1984-01-01

The constituents of the secretory immunoglobulin A system (dimeric IgA, total secretory component and free secretory component) were measured in sputum sol phase, tracheal aspirates, and bronchoalveolar lavage fluids from 15 patients undergoing fibreoptic bronchoscopy. All of the proteins showed a progressive decrease in concentration from sputum to the bronchoalveolar lavage fluids (2p less than 0.001). Standardisation of samples by means of protein concentration ratios showed that all secretions were generally similar in respect of their secretory IgA profiles, although major differences remained in some individual patients. The between patient variability of the results was generally reduced by the use of protein concentration ratios, allowing closer comparison between subjects. When the secretion albumin concentration was used as a standard, however, it increased the variability of the sputum sol phase IgA components (2p less than 0.01), whereas it decreased the variability of the IgA components in the bronchoalveolar lavage fluid (2p less than 0.05). The role of albumin as a standard protein for assessing the secretory IgA system in lung secretions remains uncertain. PMID:6463931

Role of fimV in type II secretion system-dependent protein secretion of Pseudomonas aeruginosa on solid medium.

PubMed

Michel, Gérard P F; Aguzzi, Anthony; Ball, Geneviève; Soscia, Chantal; Bleves, Sophie; Voulhoux, Romé

2011-07-01

Although classical type II secretion systems (T2SSs) are widely present in Gram-negative bacteria, atypical T2SSs can be found in some species. In Pseudomonas aeruginosa, in addition to the classical T2SS Xcp, it was reported that two genes, xphA and xqhA, located outside the xcp locus were organized in an operon (PaQa) which encodes the orphan PaQa subunit. This subunit is able to associate with other components of the classical Xcp machinery to form a functional hybrid T2SS. In the present study, using a transcriptional lacZ fusion, we found that the PaQa operon was more efficiently expressed (i) on solid LB agar than in liquid LB medium, (ii) at 25 °C than at 37 °C and (iii) at an early stage of growth. These results suggested an adaptation of the hybrid system to particular environmental conditions. Transposon mutagenesis led to the finding that vfr and fimV genes are required for optimal expression of the orphan PaQa operon in the defined growth conditions used. Using an original culturing device designed to monitor secretion on solid medium, the ring-plate system, we found that T2SS-dependent secretion of exoproteins, namely the elastase LasB, was affected in a fimV deletion mutant. Our findings led to the discovery of an interplay between FimV and the global regulator Vfr triggering the modulation of the level of Vfr and consequently the modulation of T2SS-dependent secretion on solid medium.

Mental health consultant to law enforcement: Secret Service development of a Mental Health Liaison Program.

PubMed

Coggins, M H; Pynchon, M R

1998-01-01

The Mental Health Liaison Program developed and used by the Secret Service is presented as a model for comprehensive, multidimensional interactions between law enforcement and mental health systems, with particular focus on assessing and preventing violent behavior. The structure of the program pairs consultants--psychologists and psychiatrists--with Secret Service field offices to provide (a) consultation regarding risk assessment and case management of individuals who threaten or display inappropriate interest in the President or other protectees; (b) training for agents on risk assessment, mental illness, and mental health care issues; and (c) liaison activities between the Secret Service and the mental health community. Practical benefits to the Secret Service are discussed to encourage more systematic use of broad based psychological and psychiatric consultation to law enforcement, with a goal of enhanced intersystem communication and collaboration. The need for program evaluation and outcome research is discussed in the context of applying the model to improve other mental health and law enforcement systems interactions.

Heterologous Protein Secretion in Lactobacilli with Modified pSIP Vectors

PubMed Central

Karlskås, Ingrid Lea; Maudal, Kristina; Axelsson, Lars; Rud, Ida; Eijsink, Vincent G. H.; Mathiesen, Geir

2014-01-01

We describe new variants of the modular pSIP-vectors for inducible gene expression and protein secretion in lactobacilli. The basic functionality of the pSIP system was tested in Lactobacillus strains representing 14 species using pSIP411, which harbors the broad-host-range Lactococcus lactis SH71rep replicon and a β-glucuronidase encoding reporter gene. In 10 species, the inducible gene expression system was functional. Based on these results, three pSIP vectors with different signal peptides were modified by replacing their narrow-host-range L. plantarum 256rep replicon with SH71rep and transformed into strains of five different species of Lactobacillus. All recombinant strains secreted the target protein NucA, albeit with varying production levels and secretion efficiencies. The Lp_3050 derived signal peptide generally resulted in the highest levels of secreted NucA. These modified pSIP vectors are useful tools for engineering a wide variety of Lactobacillus species. PMID:24614815

How can we improve stroke thrombolysis rates? A review of health system factors and approaches associated with thrombolysis administration rates in acute stroke care.

PubMed

Paul, Christine L; Ryan, Annika; Rose, Shiho; Attia, John R; Kerr, Erin; Koller, Claudia; Levi, Christopher R

2016-04-08

Thrombolysis using intravenous (IV) tissue plasminogen activator (tPA) is one of few evidence-based acute stroke treatments, yet achieving high rates of IV tPA delivery has been problematic. The 4.5-h treatment window, the complexity of determining eligibility criteria and the availability of expertise and required resources may impact on treatment rates, with barriers encountered at the levels of the individual clinician, the social context and the health system itself. The review aimed to describe health system factors associated with higher rates of IV tPA administration for ischemic stroke and to identify whether system-focussed interventions increased tPA rates for ischemic stroke. Published original English-language research from four electronic databases spanning 1997-2014 was examined. Observational studies of the association between health system factors and tPA rates were described separately from studies of system-focussed intervention strategies aiming to increase tPA rates. Where study outcomes were sufficiently similar, a pooled meta-analysis of outcomes was conducted. Forty-one articles met the inclusion criteria: 7 were methodologically rigorous interventions that met the Cochrane Collaboration Evidence for Practice and Organization of Care (EPOC) study design guidelines and 34 described observed associations between health system factors and rates of IV tPA. System-related factors generally associated with higher IV tPA rates were as follows: urban location, centralised or hub and spoke models, treatment by a neurologist/stroke nurse, in a neurology department/stroke unit or teaching hospital, being admitted by ambulance or mobile team and stroke-specific protocols. Results of the intervention studies suggest that telemedicine approaches did not consistently increase IV tPA rates. Quality improvement strategies appear able to provide modest increases in stroke thrombolysis (pooled odds ratio = 2.1, p = 0.05). In order to improve IV tPA rates in acute stroke care, specific health system factors need to be targeted. Multi-component quality improvement approaches can improve IV tPA rates for stroke, although more thoughtfully designed and well-reported trials are required to safely increase rates of IV tPA to eligible stroke patients.