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Bepperling, A., F. Alte, T. Kriehuber, N. Braun, S. Weinkauf, M. Groll, M. Haslbeck i J. Buchner. "Alternative bacterial two-component small heat shock protein systems". Proceedings of the National Academy of Sciences 109, nr 50 (26.11.2012): 20407–12. http://dx.doi.org/10.1073/pnas.1209565109.
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Ventura, Marco, Carlos Canchaya, Ziding Zhang, Gerald F. Fitzgerald i Douwe van Sinderen. "Molecular Characterization of hsp20, Encoding a Small Heat Shock Protein of Bifidobacterium breve UCC2003". Applied and Environmental Microbiology 73, nr 14 (18.05.2007): 4695–703. http://dx.doi.org/10.1128/aem.02496-06.
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ABSTRACT Small heat shock proteins (sHSPs) are members of a diverse family of stress proteins that are important in cells to protect proteins under stressful conditions. Genome analysis of Bifidobacterium breve UCC2003 revealed a single sHSP-encoding gene, which was classified as a hsp20 gene by comparative analyses. Genomic surveillance of available genome sequences indicated that hsp20 homologs are not widely distributed in bacteria. In members of the genus Bifidobacterium, this gene appears to be present in only 7 of the 30 currently described species. Moreover, phylogenetic analysis using all available bacterial and eukaryotic sHSP sequences revealed a close relationship between bifidobacterial HSP20 and the class B sHSPs found in members of the division Firmicutes. The results of this comparative analysis and variation in codon usage content suggest that hsp20 was acquired by certain bifidobacteria through horizontal gene transfer. Analysis by slot blot, Northern blot, and primer extension experiments showed that transcription of hsp20 is strongly induced in response to severe heat shock regimens and by osmotic shock.
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Whiston, Emily A., Norito Sugi, Merideth C. Kamradt, Coralynn Sack, Susan R. Heimer, Michael Engelbert, Eric F. Wawrousek, Michael S. Gilmore, Bruce R. Ksander i Meredith S. Gregory. "αB-Crystallin Protects Retinal Tissue during Staphylococcus aureus- Induced Endophthalmitis". Infection and Immunity 76, nr 4 (28.01.2008): 1781–90. http://dx.doi.org/10.1128/iai.01285-07.
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ABSTRACT Bacterial infections of the eye highlight a dilemma that is central to all immune-privileged sites. On the one hand, immune privilege limits inflammation to prevent bystander destruction of normal tissue and loss of vision. On the other hand, bacterial infections require a robust inflammatory response for rapid clearance of the pathogen. We demonstrate that the retina handles this dilemma, in part, by activation of a protective heat shock protein. During Staphylococcus aureus-induced endophthalmitis, the small heat shock protein αB-crystallin is upregulated in the retina and prevents apoptosis during immune clearance of the bacteria. In the absence of αB-crystallin, mice display increased retinal apoptosis and retinal damage. We found that S. aureus produces a protease capable of cleaving αB-crystallin to a form that coincides with increased retinal apoptosis and tissue destruction. We conclude that αB-crystallin is important in protecting sensitive retinal tissue during destructive inflammation that occurs during bacterial endophthalmitis.
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Large, Andrew T., Martin D. Goldberg i Peter A. Lund. "Chaperones and protein folding in the archaea". Biochemical Society Transactions 37, nr 1 (20.01.2009): 46–51. http://dx.doi.org/10.1042/bst0370046.
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A survey of archaeal genomes for the presence of homologues of bacterial and eukaryotic chaperones reveals several interesting features. All archaea contain chaperonins, also known as Hsp60s (where Hsp is heat-shock protein). These are more similar to the type II chaperonins found in the eukaryotic cytosol than to the type I chaperonins found in bacteria, mitochondria and chloroplasts, although some archaea also contain type I chaperonin homologues, presumably acquired by horizontal gene transfer. Most archaea contain several genes for these proteins. Our studies on the type II chaperonins of the genetically tractable archaeon Haloferax volcanii have shown that only one of the three genes has to be present for the organisms to grow, but that there is some evidence for functional specialization between the different chaperonin proteins. All archaea also possess genes for prefoldin proteins and for small heat-shock proteins, but they generally lack genes for Hsp90 and Hsp100 homologues. Genes for Hsp70 (DnaK) and Hsp40 (DnaJ) homologues are only found in a subset of archaea. Thus chaperone-assisted protein folding in archaea is likely to display some unique features when compared with that in eukaryotes and bacteria, and there may be important differences in the process between euryarchaea and crenarchaea.
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Yin, Huaqun, Min Tang, Zhijun Zhou, Xian Fu, Li Shen, Yili Liang, Qian Li, Hongwei Liu i Xueduan Liu. "Distinctive heat-shock response of bioleaching microorganismAcidithiobacillus ferrooxidansobserved using genome-wide microarray". Canadian Journal of Microbiology 58, nr 5 (maj 2012): 628–36. http://dx.doi.org/10.1139/w2012-023.
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Temperature plays an important role in the heap bioleaching. The maldistribution of ventilation in the heap leads to local hyperthermia, which does exert a tremendous stress on bioleaching microbes. In this study, the genome-wide expression profiles of Acidithiobacillus ferrooxidans at 40 °C were detected using the microarray. The results showed that some classic proteases like Lon and small heat-shock proteins were not induced, and heat-inducible membrane proteins were suggested to be under the control of σE. Moreover, expression changes of energy metabolism are noteworthy, which is different from that in heterotrophic bacteria upon heat stress. The induced enzymes catalyzed the central carbon metabolism pathway that might mainly provide precursors of amino acids for protein synthesis. These results will deepen the understanding of the mechanisms of heat-shock response on autotrophic bacteria.
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Zhang, Bo, Sean P. Leonard, Yiyuan Li i Nancy A. Moran. "Obligate bacterial endosymbionts limit thermal tolerance of insect host species". Proceedings of the National Academy of Sciences 116, nr 49 (18.11.2019): 24712–18. http://dx.doi.org/10.1073/pnas.1915307116.
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The thermal tolerance of an organism limits its ecological and geographic ranges and is potentially affected by dependence on temperature-sensitive symbiotic partners. Aphid species vary widely in heat sensitivity, but almost all aphids are dependent on the nutrient-provisioning intracellular bacterium Buchnera, which has evolved with aphids for 100 million years and which has a reduced genome potentially limiting heat tolerance. We addressed whether heat sensitivity of Buchnera underlies variation in thermal tolerance among 5 aphid species. We measured how heat exposure of juvenile aphids affects later survival, maturation time, and fecundity. At one extreme, heat exposure of Aphis gossypii enhanced fecundity and had no effect on the Buchnera titer. In contrast, heat suppressed Buchnera populations in Aphis fabae, which suffered elevated mortality, delayed development and reduced fecundity. Likewise, in Acyrthosiphon kondoi and Acyrthosiphon pisum, heat caused rapid declines in Buchnera numbers, as well as reduced survivorship, development rate, and fecundity. Fecundity following heat exposure is severely decreased by a Buchnera mutation that suppresses the transcriptional response of a gene encoding a small heat shock protein. Similarly, absence of this Buchnera heat shock gene may explain the heat sensitivity of Ap. fabae. Fluorescent in situ hybridization revealed heat-induced deformation and shrinkage of bacteriocytes in heat-sensitive species but not in heat-tolerant species. Sensitive and tolerant species also differed in numbers and transcriptional responses of heat shock genes. These results show that shifts in Buchnera heat sensitivity contribute to host variation in heat tolerance.
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Avelange-Macherel, Marie-Hélène, Aurélia Rolland, Marie-Pierre Hinault, Dimitri Tolleter i David Macherel. "The Mitochondrial Small Heat Shock Protein HSP22 from Pea is a Thermosoluble Chaperone Prone to Co-Precipitate with Unfolding Client Proteins". International Journal of Molecular Sciences 21, nr 1 (21.12.2019): 97. http://dx.doi.org/10.3390/ijms21010097.
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The small heat shock proteins (sHSPs) are molecular chaperones that share an alpha-crystallin domain but display a high diversity of sequence, expression, and localization. They are especially prominent in plants, populating most cellular compartments. In pea, mitochondrial HSP22 is induced by heat or oxidative stress in leaves but also strongly accumulates during seed development. The molecular function of HSP22 was addressed by studying the effect of temperature on its structural properties and chaperone effects using a recombinant or native protein. Overexpression of HSP22 significantly increased bacterial thermotolerance. The secondary structure of the recombinant protein was not affected by temperature in contrast with its quaternary structure. The purified protein formed large polydisperse oligomers that dissociated upon heating (42 °C) into smaller species (mainly monomers). The recombinant protein appeared thermosoluble but precipitated with thermosensitive proteins upon heat stress in assays either with single protein clients or within complex extracts. As shown by in vitro protection assays, HSP22 at high molar ratio could partly prevent the heat aggregation of rhodanese but not of malate dehydrogenase. HSP22 appears as a holdase that could possibly prevent the aggregation of some proteins while co-precipitating with others to facilitate their subsequent refolding by disaggregases or clearance by proteases.
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Laksanalamai, Pongpan, Dennis L. Maeder i Frank T. Robb. "Regulation and Mechanism of Action of the Small Heat Shock Protein from the Hyperthermophilic ArchaeonPyrococcus furiosus". Journal of Bacteriology 183, nr 17 (1.09.2001): 5198–202. http://dx.doi.org/10.1128/jb.183.17.5198-5202.2001.
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ABSTRACT The small heat shock protein (sHSP) from the hyperthermophilePyrococcus furiosus was specifically induced at the level of transcription by heat shock at 105°C. The gene encoding this protein was cloned and overexpressed in Escherichia coli. The recombinant sHSP prevented the majority of E. coli proteins from aggregating in vitro for up to 40 min at 105°C. The sHSP also prevented bovine glutamate dehydrogenase from aggregating at 56°C. Survivability of E. colioverexpressing the sHSP was enhanced approximately sixfold during exposure to 50°C for 2 h compared with the control culture, which did not express the sHSP. Apparently, the sHSP confers a survival advantage on mesophilic bacteria by preventing protein aggregation at supraoptimal temperatures.
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Lupoli, Tania J., Allison Fay, Carolina Adura, Michael S. Glickman i Carl F. Nathan. "Reconstitution of aMycobacterium tuberculosisproteostasis network highlights essential cofactor interactions with chaperone DnaK". Proceedings of the National Academy of Sciences 113, nr 49 (21.11.2016): E7947—E7956. http://dx.doi.org/10.1073/pnas.1617644113.
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During host infection,Mycobacterium tuberculosis(Mtb) encounters several types of stress that impair protein integrity, including reactive oxygen and nitrogen species and chemotherapy. The resulting protein aggregates can be resolved or degraded by molecular machinery conserved from bacteria to eukaryotes. Eukaryotic Hsp104/Hsp70 and their bacterial homologs ClpB/DnaK are ATP-powered chaperones that restore toxic protein aggregates to a native folded state. DnaK is essential inMycobacterium smegmatis, and ClpB is involved in asymmetrically distributing damaged proteins during cell division as a mechanism of survival in Mtb, commending both proteins as potential drug targets. However, their molecular partners in protein reactivation have not been characterized in mycobacteria. Here, we reconstituted the activities of the Mtb ClpB/DnaK bichaperone system with the cofactors DnaJ1, DnaJ2, and GrpE and the small heat shock protein Hsp20. We found that DnaJ1 and DnaJ2 activate the ATPase activity of DnaK differently. A point mutation in the highly conserved HPD motif of the DnaJ proteins abrogates their ability to activate DnaK, although the DnaJ2 mutant still binds to DnaK. The purified Mtb ClpB/DnaK system reactivated a heat-denatured model substrate, but the DnaJ HPD mutants inhibited the reaction. Finally, either DnaJ1 or DnaJ2 is required for mycobacterial viability, as is the DnaK-activating activity of a DnaJ protein. These studies lay the groundwork for strategies to target essential chaperone–protein interactions in Mtb, the leading cause of death from a bacterial infection.
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Oliver, Cristian, Patricio Sánchez, Karla Valenzuela, Mauricio Hernández, Juan Pablo Pontigo, Maria C. Rauch, Rafael A. Garduño, Ruben Avendaño-Herrera i Alejandro J. Yáñez. "Subcellular Location of Piscirickettsia salmonis Heat Shock Protein 60 (Hsp60) Chaperone by Using Immunogold Labeling and Proteomic Analysis". Microorganisms 8, nr 1 (15.01.2020): 117. http://dx.doi.org/10.3390/microorganisms8010117.
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Piscirickettsia salmonis is the causative bacterial agent of piscirickettsiosis, a systemic fish disease that significantly impacts the Chilean salmon industry. This bacterium possesses a type IV secretion system (T4SS), several proteins of the type III secretion system (T3SS), and a single heat shock protein 60 (Hsp60/GroEL). It has been suggested that due to its high antigenicity, the P. salmonis Hsp60 could be surface-exposed, translocated across the membrane, and (or) secreted into the extracellular matrix. This study tests the hypothesis that P. salmonis Hsp60 could be located on the bacterial surface. Immunogold electron microscopy and proteomic analyses suggested that although P. salmonis Hsp60 was predominantly associated with the bacterial cell cytoplasm, Hsp60-positive spots also exist on the bacterial cell envelope. IgY antibodies against P. salmonis Hsp60 protected SHK-1 cells against infection. Several bioinformatics approaches were used to assess Hsp60 translocation by the T4SS, T3SS, and T6SS, with negative results. These data support the hypothesis that small amounts of Hsp60 must reach the bacterial cell surface in a manner probably not mediated by currently characterized secretion systems, and that they remain biologically active during P. salmonis infection, possibly mediating adherence and (or) invasion.
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Piróg, Artur, Francesca Cantini, Łukasz Nierzwicki, Igor Obuchowski, Bartłomiej Tomiczek, Jacek Czub i Krzysztof Liberek. "Two Bacterial Small Heat Shock Proteins, IbpA and IbpB, Form a Functional Heterodimer". Journal of Molecular Biology 433, nr 15 (lipiec 2021): 167054. http://dx.doi.org/10.1016/j.jmb.2021.167054.
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Fu, Xinmiao, Zengyi Chang, Xiaodong Shi, Dongbo Bu i Chao Wang. "Multilevel structural characteristics for the natural substrate proteins of bacterial small heat shock proteins". Protein Science 23, nr 2 (16.12.2013): 229–37. http://dx.doi.org/10.1002/pro.2404.
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Rasouly, Aviram, Chen Davidovich i Eliora Z. Ron. "The Heat Shock Protein YbeY Is Required for Optimal Activity of the 30S Ribosomal Subunit". Journal of Bacteriology 192, nr 18 (16.07.2010): 4592–96. http://dx.doi.org/10.1128/jb.00448-10.
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ABSTRACT The highly conserved bacterial ybeY gene is a heat shock gene whose function is not fully understood. Previously, we showed that the YbeY protein is involved in protein synthesis, as Escherichia coli mutants with ybeY deleted exhibit severe translational defects in vivo. Here we show that the in vitro activity of the translation machinery of ybeY deletion mutants is significantly lower than that of the wild type. We also show that the lower efficiency of the translation machinery is due to impaired 30S small ribosomal subunits.
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Arvans, Donna L., Stephan R. Vavricka, Hongyu Ren, Mark W. Musch, Lisa Kang, Flavio G. Rocha, Alvaro Lucioni, Jerrold R. Turner, John Alverdy i Eugene B. Chang. "Luminal bacterial flora determines physiological expression of intestinal epithelial cytoprotective heat shock proteins 25 and 72". American Journal of Physiology-Gastrointestinal and Liver Physiology 288, nr 4 (kwiecień 2005): G696—G704. http://dx.doi.org/10.1152/ajpgi.00206.2004.
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Heat shock proteins (HSP) 25 and 72 are expressed normally by surface colonocytes but not by small intestinal enterocytes. We hypothesized that luminal commensal microflora maintain the observed colonocyte HSP expression. The ability of the small intestine to respond to bacteria and their products and modulate HSPs has not been determined. The effects of luminal bacterial flora in surgically created midjejunal self-filling (SFL) vs. self-emptying (SEL) small-bowel blind loops on epithelial HSP expression were studied. HSP25 and HSP72 expression were assessed by immunoblot and immunohistochemistry. SFL were chronically colonized, whereas SEL contained levels of bacteria normal for the proximal small intestine. SFL creation significantly increased HSP25 and HSP72 expression relative to corresponding sections from SEL. Metronidazole treatment, which primarily affects anaerobic bacteria as well as a diet lacking fermentable fiber, significantly decreased SFL HSP expression. Small bowel incubation with butyrate ex vivo induced a sustained and significant upregulation of HSP25 and altered HSP72 expression, confirming the role of short-chain fatty acids. To determine whether HSPs induction altered responses to an injury, effects of the oxidant, monochloramine, on epithelial resistance and short-circuit current ( Isc) responses to carbachol and glucose were compared. Increased SFL HSP expression was associated with protection against oxidant-induced decreases in transmural resistance and Iscresponses to glucose, but not secretory responses to carbachol. In conclusion, luminal microflora and their metabolic byproducts direct expression of HSPs in gut epithelial cells, an effect that contributes to preservation of epithelial cell viability under conditions of stress.
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Kim, Hyesoon, i Yeh-Jin Ahn. "Expression of a Gene Encoding the Carrot HSP17.7 in Escherichia coli Enhances Cell Viability and Protein Solubility Under Heat Stress". HortScience 44, nr 3 (czerwiec 2009): 866–69. http://dx.doi.org/10.21273/hortsci.44.3.866.
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DcHSP17.7, a small heat shock protein from carrot (Daucus carota L.), was expressed in Escherichia coli to examine its functional mechanism under heat stress. When transformed cells expressing DcHSP17.7 were exposed to 50 °C for 1 h, the number of viable cells was ≈4-fold higher than that of control. When the amount of soluble proteins was compared, it was more than twofold higher in transformed cells expressing DcHSP17.7 than that in control, suggesting that DcHSP17.7 may function as a molecular chaperone preventing heat-inducible protein degradation. Native-PAGE followed by immunoblot analysis showed that in transformed E. coli, DcHSP17.7 was present in an oligomeric complex, ≈300 kDa in molecular mass, on isopropyl b-D-thiogalactopyranoside treatment. However, the complex rapidly disappeared when bacterial cells were exposed to heat stress. In carrot, DcHSP17.7 was found in the similar-sized complex (≈300 kDa), but only during heat stress (40 °C), suggesting that the functional structure of DcHSP17.7 may be different in transformed E. coli from that in carrot.
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Iburg, Manuel, Dmytro Puchkov, Irving U. Rosas-Brugada, Linda Bergemann, Ulrike Rieprecht i Janine Kirstein. "The noncanonical small heat shock protein HSP-17 from Caenorhabditis elegans is a selective protein aggregase". Journal of Biological Chemistry 295, nr 10 (30.01.2020): 3064–79. http://dx.doi.org/10.1074/jbc.ra119.011185.
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Small heat shock proteins (sHsps) are conserved, ubiquitous members of the proteostasis network. Canonically, they act as “holdases” and buffer unfolded or misfolded proteins against aggregation in an ATP-independent manner. Whereas bacteria and yeast each have only two sHsps in their genomes, this number is higher in metazoan genomes, suggesting a spatiotemporal and functional specialization in higher eukaryotes. Here, using recombinantly expressed and purified proteins, static light-scattering analysis, and disaggregation assays, we report that the noncanonical sHsp HSP-17 of Caenorhabditis elegans facilitates aggregation of model substrates, such as malate dehydrogenase (MDH), and inhibits disaggregation of luciferase in vitro. Experiments with fluorescently tagged HSP-17 under the control of its endogenous promoter revealed that HSP-17 is expressed in the digestive and excretory organs, where its overexpression promotes the aggregation of polyQ proteins and of the endogenous kinase KIN-19. Systemic depletion of hsp-17 shortens C. elegans lifespan and severely reduces fecundity and survival upon prolonged heat stress. HSP-17 is an abundant protein exhibiting opposing chaperone activities on different substrates, indicating that it is a selective protein aggregase with physiological roles in development, digestion, and osmoregulation.
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Feng, Jinlin. "ITRAQ-Based Proteomic Analysis of The Response to Ralstonia solanacearum in Potato". Pakistan Journal of Agricultural Sciences 59, nr 02 (1.01.2022): 165–71. http://dx.doi.org/10.21162/pakjas/22.1347.
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Bacterial wilt is a serious disease of potato (Solanum tuberosum L.) caused by the soil-borne pathogenic bacterium Ralstonia solanacearum. Detecting changes in protein abundance in potato plants in response to R. solanacearum is a pivotal step in uncovering the molecular interactions of plant pathogens. In this study, using the disease-resistant cultivar ‘Zhongshu 3’, we analyzed protein expression in potato seedlings inoculated with R. solanacearum every 12 h for a total of 72 h using isobaric tags for relative and absolute quantitation-based proteomics. Our results indicate that pathogenesis-related proteins, stressrelated proteins, non-specific lipid transfer proteins, small heat shock proteins, and osmotin-like proteins were up-regulated in response to pathogen infection at different time points. The accumulation of these proteins in response to biotic stress suggests that these proteins play an important role in pathogen resistance. Our findings will provide an important basis for characterizing the role of these proteins in increasing plant resistance to pathogens and in breeding bacterial wilt-resistant plants.
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Maitre, Magali, Stéphanie Weidmann, Florence Dubois-Brissonnet, Vanessa David, Jacques Covès i Jean Guzzo. "Adaptation of the Wine Bacterium Oenococcus oeni to Ethanol Stress: Role of the Small Heat Shock Protein Lo18 in Membrane Integrity". Applied and Environmental Microbiology 80, nr 10 (28.02.2014): 2973–80. http://dx.doi.org/10.1128/aem.04178-13.
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ABSTRACTMalolactic fermentation in wine is often carried out byOenococcus oeni. Wine is a stressful environment for bacteria because ethanol is a toxic compound that impairs the integrity of bacterial membranes. The small heat shock protein (sHsp) Lo18 is an essential actor of the stress response inO. oeni. Lo18 prevents the thermal aggregation of proteins and plays a crucial role in membrane quality control. Here, we investigated the interaction between Lo18 and four types of liposomes: one was prepared fromO. oenigrown under optimal growth conditions (here, control liposomes), one was prepared fromO. oenigrown in the presence of 8% ethanol (here, ethanol liposomes), one was prepared from synthetic phospholipids, and one was prepared from phospholipids fromBacillus subtilisorLactococcus lactis. We observed the strongest interaction between Lo18 and control liposomes. The lipid binding activity of Lo18 required the dissociation of oligomeric structures into dimers. Protein protection experiments carried out in the presence of the liposomes fromO. oenisuggested that Lo18 had a higher affinity for control liposomes than for a model protein. In anisotropy experiments, we mimicked ethanol action by temperature-dependent fluidization of the liposomes. Results suggest that the principal determinant of Lo18-membrane interaction is lipid bilayer phase behavior rather than phospholipid composition. We suggest a model to describe the ethanol adaptation ofO. oeni. This model highlights the dual role of Lo18 in the protection of proteins from aggregation and membrane stabilization and suggests how modifications of phospholipid content may be a key factor determining the balance between these two functions.
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Studer, Sonja, i Franz Narberhaus. "Chaperone Activity and Homo- and Hetero-oligomer Formation of Bacterial Small Heat Shock Proteins". Journal of Biological Chemistry 275, nr 47 (7.09.2000): 37212–18. http://dx.doi.org/10.1074/jbc.m004701200.
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Zav'yalov, Vladimir P., Galina A. Zav'yalova, Alexander I. Denesyuk, Matthias Gaestel i Timo Korpela. "Structural and functional homology between periplasmic bacterial molecular chaperones and small heat shock proteins". FEMS Immunology & Medical Microbiology 11, nr 4 (lipiec 1995): 265–72. http://dx.doi.org/10.1111/j.1574-695x.1995.tb00155.x.
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Jobin, Michel-Philippe, Dominique Garmyn, Charles Diviès i Jean Guzzo. "The Oenococcus oeni clpX Homologue Is a Heat Shock Gene Preferentially Expressed in Exponential Growth Phase". Journal of Bacteriology 181, nr 21 (1.11.1999): 6634–41. http://dx.doi.org/10.1128/jb.181.21.6634-6641.1999.
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ABSTRACT Using degenerated primers from conserved regions of previously studied clpX gene products, we cloned the clpXgene of the malolactic bacterium Oenococcus oeni. TheclpX gene was sequenced, and the deduced protein of 413 amino acids (predicted molecular mass of 45,650 Da) was highly similar to previously analyzed clpX gene products from other organisms. An open reading frame located upstream of theclpX gene was identified as the tig gene by similarity of its predicted product to other bacterial trigger factors. ClpX was purified by using a maltose binding protein fusion system and was shown to possess an ATPase activity. Northern analyses indicated the presence of two independent 1.6-kb monocistronic clpXand tig mRNAs and also showed an increase inclpX mRNA amount after a temperature shift from 30 to 42°C. The clpX transcript is abundant in the early exponential growth phase and progressively declines to undetectable levels in the stationary phase. Thus, unlike hsp18, the gene encoding one of the major small heat shock proteins ofOenococcus oeni, clpX expression is related to the exponential growth phase and requires de novo protein synthesis. Primer extension analysis identified the 5′ end of clpXmRNA which is located 408 nucleotides upstream of a putative AUA start codon. The putative transcription start site allowed identification of a predicted promoter sequence with a high similarity to the consensus sequence found in the housekeeping gene promoter of gram-positive bacteria as well as Escherichia coli.
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Sriramulu, Dinesh Diraviam. "Small Heat Shock Proteins Produced by Pseudomonas Aeruginosa Clonal Variants Isolated from Diverse Niches". Proteomics Insights 2 (styczeń 2009): PRI.S3760. http://dx.doi.org/10.4137/pri.s3760.
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Genomic islands interspersed in the chromosome of P. aeruginosa led to inter- and intraclonal diversity. Recently, a particular clone of P. aeruginosa called clone C was isolated from cystic fibrosis (CF) patients, clinical and non-clinical habitats throughout Europe and in Canada. P. aeruginosa clone C strains harbour up to several hundred acquired genes involved in the adaptation of bacteria to diverse niches. Two genes ( hp25 and hp18) from one of the hypervariable regions in the chromosome of clone C strains were highly expressed under standard culture conditions as well as under conditions that mimicked CF sputum environment. Protein sequence analysis revealed that Hp25 and Hp18 belonged to small heat shock protein (sHSP) family. Hp25 protein possessed α-crystallin domain, which is a conserved region among heat shock proteins involved in diverse functions. Sequence homology search revealed that in the Methylobacillus flagellatus genome both genes were situated close to each other and the hp25 gene is found among a few other members of Proteobacteria. Expression of hp25 and hp18 by inter- and intraclonal strains of P. aeruginosa suggested that both genes were present in the stable part of the hypervariable region at the toxR locus and might play a role in their adaptation to diverse niches including the CF lung environment.
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Qiu, Zhijun, i Thomas H. MacRae. "ArHsp21, a developmentally regulated small heat-shock protein synthesized in diapausing embryos of Artemia franciscana". Biochemical Journal 411, nr 3 (14.04.2008): 605–11. http://dx.doi.org/10.1042/bj20071472.
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Embryos of the crustacean, Artemia franciscana, undergo alternative developmental pathways, producing either larvae or encysted embryos (cysts). The cysts enter diapause, characterized by exceptionally high resistance to environmental stress, a condition thought to involve the sHSP (small heat-shock protein), p26. Subtractive hybridization has revealed another sHSP, termed ArHsp21, in diapause-destined Artemia embryos. ArHsp21 shares sequence similarity with p26 and sHSPs from other organisms, especially in the α-crystallin domain. ArHsp21 is the product of a single gene and its synthesis occurred exclusively in diapause-destined embryos. Specifically, ArHsp21 mRNA appeared 2 days post-fertilization, followed 1 day later by the protein, and then increased until embryo release at day 5. No ArHsp21 protein was detected in embryos developing directly into larvae, although there was a small amount of mRNA at 3 days post-fertilization. The protein was degraded during post-diapause development and had disappeared completely from second instar larvae. ArHsp21 formed large oligomers in encysted embryos and transformed bacteria. When purified from bacteria, ArHsp21 functioned as a molecular chaperone in vitro, preventing heat-induced aggregation of citrate synthase and reduction-driven denaturation of insulin. Sequence characteristics, synthesis patterns and functional properties demonstrate clearly that ArHsp21 is an sHSP able to chaperone other proteins and contribute to stress tolerance during diapause. As such, ArHsp21 would augment p26 chaperone activity and it may also possess novel activities that benefit Artemia embryos exposed to stress.
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Rajaram, Hema, Akhilesh Kumar Chaurasia i Shree Kumar Apte. "Cyanobacterial heat-shock response: role and regulation of molecular chaperones". Microbiology 160, nr 4 (1.04.2014): 647–58. http://dx.doi.org/10.1099/mic.0.073478-0.
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Cyanobacteria constitute a morphologically diverse group of oxygenic photoautotrophic microbes which range from unicellular to multicellular, and non-nitrogen-fixing to nitrogen-fixing types. Sustained long-term exposure to changing environmental conditions, during their three billion years of evolution, has presumably led to their adaptation to diverse ecological niches. The ability to maintain protein conformational homeostasis (folding–misfolding–refolding or aggregation–degradation) by molecular chaperones holds the key to the stress adaptability of cyanobacteria. Although cyanobacteria possess several genes encoding DnaK and DnaJ family proteins, these are not the most abundant heat-shock proteins (Hsps), as is the case in other bacteria. Instead, the Hsp60 family of proteins, comprising two phylogenetically conserved proteins, and small Hsps are more abundant during heat stress. The contribution of the Hsp100 (ClpB) family of proteins and of small Hsps in the unicellular cyanobacteria (Synechocystis and Synechococcus) as well as that of Hsp60 proteins in the filamentous cyanobacteria (Anabaena) to thermotolerance has been elucidated. The regulation of chaperone genes by several cis-elements and trans-acting factors has also been well documented. Recent studies have demonstrated novel transcriptional and translational (mRNA secondary structure) regulatory mechanisms in unicellular cyanobacteria. This article provides an insight into the heat-shock response: its organization, and ecophysiological regulation and role of molecular chaperones, in unicellular and filamentous nitrogen-fixing cyanobacterial strains.
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Wasilah, Ummi, Dian A. G. Perwitasari i Mukhamad Su'udi. "Peran Chaperone Pada Tumbuhan: Mini Review". JURNAL BIOLOGI PAPUA 11, nr 2 (31.10.2019): 110–15. http://dx.doi.org/10.31957/jbp.880.
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Plants respond to various conditions in the surrounding environment, whether favorable conditions or vice versa. Abiotic and biotic factors affect plant responses such as temperature, humidity, salinity, insects and pathogens such as viruses and bacteria. Plants have a defense system in tolerancing stress from the surrounding environment, for example heat shock protein (HSP) is a chaperone protein that plays a role in plant defenses when experiencing stress to the temperature. HSP is classified into six families based on their molecular weight, namely HSP100, HSP90, HSP70, HSP60, HSP40, and small HSP. Each has a role in maintaining the stability of plant metabolism. HSP is especially important for correct protein refolding, preventing degradation and denaturation of protein. Key words: plants; chaperone; heat shock protein; refolding; protein denaturation.
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Musch, Mark W., Elaine O. Petrof, Keishi Kojima, Hongyu Ren, Derek M. McKay i Eugene B. Chang. "Bacterial Superantigen-Treated Intestinal Epithelial Cells Upregulate Heat Shock Proteins 25 and 72 and Are Resistant to Oxidant Cytotoxicity". Infection and Immunity 72, nr 6 (czerwiec 2004): 3187–94. http://dx.doi.org/10.1128/iai.72.6.3187-3194.2004.
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ABSTRACT While the pathological events evoked by infection are commonly described, effective host responses to bacteria and their products should primarily be protective. Heat shock protein (Hsp) expression is upregulated by many stimuli and serves to maintain intracellular protein integrity. The ability of the prototypic superantigen, Staphylococcus aureus enterotoxin B (SEB) to induce Hsps was investigated with BALB/c mice and by in vitro addition to the murine small intestinal epithelial cell line MSIE. SEB-treated (5 or 100 μg intraperitoneally) mice revealed increased Hsp25 and Hsp72, but not Hsc73, in jejunal lymphocytes and epithelial cells. A similar Hsp response to SEB occurred in MSIE cells and was preceded by activation of the ERK1/2 and p38 mitogen-activated protein kinases but not the SAPK/JNK pathway; pharmacological inhibition of ERK1/2, but not p38, significantly reduced SEB-induced Hsps. Moreover, SEB-treated MSIE cells were protected against oxidant-induced cytotoxicity (measured by 51Cr release) and F-actin depolymerization. Thus, SEB exposure results in a rapid induction of the Hsp25 and Hsp72 in intestinal epithelial cells, both directly and through lymphocyte activation, and we suggest that this event is important in protecting the gut from damage by Staphylococcus infection or in the reparatory process and may be a generalized response to lumen-derived bacterial toxins.
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Cocotl-Yañez, Miguel, Soledad Moreno, Sergio Encarnación, Liliana López-Pliego, Miguel Castañeda i Guadalupe Espín. "A small heat-shock protein (Hsp20) regulated by RpoS is essential for cyst desiccation resistance in Azotobacter vinelandii". Microbiology 160, nr 3 (1.03.2014): 479–87. http://dx.doi.org/10.1099/mic.0.073353-0.
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In Azotobacter vinelandii, a cyst-forming bacterium, the alternative sigma factor RpoS is essential to the formation of cysts resistant to desiccation and to synthesis of the cyst-specific lipids, alkylresorcinols. In this study, we carried out a proteome analysis of vegetative cells and cysts of A. vinelandii strain AEIV and its rpoS mutant derivative AErpoS. This analysis allowed us to identify a small heat-shock protein, Hsp20, as one of the most abundant proteins of cysts regulated by RpoS. Inactivation of hsp20 did not affect the synthesis of alkylresorcinols or the formation of cysts with WT morphology; however, the cysts formed by the hsp20 mutant strain were unable to resist desiccation. We also demonstrated that expression of hsp20 from an RpoS-independent promoter in the AErpoS mutant strain is not enough to restore the phenotype of resistance to desiccation. These results indicate that Hsp20 is essential for the resistance to desiccation of A. vinelandii cysts, probably by preventing the aggregation of proteins caused by the lack of water. To our knowledge, this is the first report of a small heat-shock protein that is essential for desiccation resistance in bacteria.
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Playford, Raymond J., Naheed Choudhry, Paul Kelly i Tania Marchbank. "Effects of Bovine Colostrum with or without Egg on In Vitro Bacterial-Induced Intestinal Damage with Relevance for SIBO and Infectious Diarrhea". Nutrients 13, nr 3 (22.03.2021): 1024. http://dx.doi.org/10.3390/nu13031024.
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Small intestinal bacterial overgrowth (SIBO) occurs commonly, is difficult to treat, and frequently recurs. Bovine colostrum (BC) and chicken eggs contain immunoglobulins and other components that possess antimicrobial, immunoregulatory, and growth factor activities; however, it is not known if they have the ability to reduce injury caused by the presence of bacteria associated with SIBO (Streptococcus, Escherichia coli, Staphylococcus, Bacteroides, Klebsiella, Enterococcus, and Proteus) and infectious diarrhea (enteropathogenic Escherichia coli, Salmonella). We examined the effects of BC, egg, or the combination, on bacterial growth and bacteria-induced changes in transepithelial electrical resistance (TEER) and bacterial translocation across confluent Caco-2 monolayers. BC, egg, or the combination did not affect bacterial growth. Adding bacteria to monolayers reduced TEER and (with minor variations among species) increased bacterial translocation, increased monolayer apoptosis (increased caspase-3 and Baxα, reduced Bcl2), increased intercellular adhesion molecule 1 (ICAM-1), and reduced cell adhesion molecules zonulin1 (ZO1) and claudin-1. BC, egg, or the combination reduced these effects (all p < 0.01) and caused additional increases in vascular endothelial growth factor (VEGF) and Heat Shock Protein 70 (Hsp70) expression. We conclude that BC ± egg strengthens mucosal integrity against a battery of bacteria relevant for SIBO and for infectious diarrhea. Oral BC ± egg may have clinical value for these conditions, especially SIBO where eradication of precipitating organisms may be difficult to achieve.
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Lee, Joohee, i Yeh-Jin Ahn. "Heterologous Expression of a Carrot Small Heat Shock Protein Increased Escherichia coli Viability under Lead and Arsenic Stresses". HortScience 48, nr 10 (październik 2013): 1323–26. http://dx.doi.org/10.21273/hortsci.48.10.1323.
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The expression and function of DcHsp17.7, a small heat shock protein (sHSP), in carrot (Daucus carota L.) was examined under lead [Pb(II)] and arsenic (arsenate) stresses. In a time course experiment, the level of DcHsp17.7 increased in carrot leaf tissue treated with lead ions or arsenate. To examine the function of DcHsp17.7, the DcHsp17.7 gene was cloned and introduced into Escherichia coli. Heterologous expression of DcHsp17.7 was confirmed by immunoblot analysis using a polyclonal antibody raised against DcHsp17.7. Lead ion and arsenate reduced bacterial cell viability. However, transgenic E. coli with accumulated DcHsp17.7 showed higher levels of survival under both lead ion and arsenate conditions compared with the vector control. Immunoblot analysis showed that the level of heterologously expressed DcHsp17.7 decreased under lead ion conditions, but remained the same under arsenate conditions. Our results suggest that DcHsp17.7 can confer tolerances to lead and arsenic stresses.
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Ahn, Yeh-Jin, i Na-Hyun Song. "A Cytosolic Heat Shock Protein Expressed in Carrot (Daucus carota L.) Enhances Cell Viability under Oxidative and Osmotic Stress Conditions". HortScience 47, nr 1 (styczeń 2012): 143–48. http://dx.doi.org/10.21273/hortsci.47.1.143.
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The expression and function of DcHsp17.7, a small heat shock protein expressed in carrot (Daucus carota L.), was examined under oxidative and osmotic stress conditions. Comparative analysis revealed that DcHsp17.7 is a cytosolic Class I protein. Sequence alignment showed that DcHsp17.7 has the characteristic α-crystalline domain-containing consensus regions I and II. Under oxidative [hydrogen peroxide (H2O2)] and osmotic (polyethylene glycol) stress conditions, DcHsp17.7 accumulated in carrot leaf tissue. To examine its function under these abiotic stress conditions, the coding sequence of DcHsp17.7 was introduced into Escherichia coli and expressed by isopropyl β-D-1-thiogalactopyranoside treatment. Under both oxidative and osmotic stress conditions, heterologously expressed DcHsp17.7 enhanced bacterial cell viability. The expression level of soluble proteins was higher in transgenic cells expressing DcHsp17.7 when compared with controls under these stress conditions. These results suggest that DcHsp17.7 confers tolerance to both oxidative and osmotic stresses and thereby functions as a molecular chaperone during the stresses examined.
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Petrof, Elaine O., Mark W. Musch, Mae Ciancio, Jun Sun, Michael E. Hobert, Erika C. Claud, Andrew Gewirtz i Eugene B. Chang. "Flagellin is required for salmonella-induced expression of heat shock protein Hsp25 in intestinal epithelium". American Journal of Physiology-Gastrointestinal and Liver Physiology 294, nr 3 (marzec 2008): G808—G818. http://dx.doi.org/10.1152/ajpgi.00362.2007.
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Flagellin is a bacterial protein responsible for activation of Toll-like receptor 5 (TLR5), which we hypothesize is involved in Salmonella's induction of cytoprotective heat shock proteins in intestinal epithelial cells. Flagellin induces the cytoprotective heat shock protein Hsp25 in different intestinal epithelial cell lines and in mouse intestine. Flagellin induces Hsp25 expression in a time-dependent manner in vitro. This effect is transcriptional, as confirmed by luciferase reporter assays and actinomycin D treatment. In addition, Hsp25 induction requires p38 MAPK activation and is only observed when flagellin is added to the basolateral side of polarized intestinal epithelial cells, consistent with the known location of TLR5. Flagellin-mediated Hsp25 induction is associated with increased protective effects against oxidant stress, an effect that is at least partially mediated by p38 MAPK. Use of small interfering RNA against Hsp25 demonstrates that flagellin-mediated protection against oxidant stress is to some degree mediated through Hsp25 induction. This suggests that, by protecting against oxidant injury, the induction of Hsp25 expression by flagellin may contribute to intestinal homeostasis. In a coculture cell model and in a mouse model of Salmonella enterica Serovar Typhimurium infection, not only does infection with wild-type and a flagellin-deletion mutant strain of Salmonella show that flagellin induces Hsp25 in vivo, but it also demonstrates that in the case of live Salmonella infection, flagellin serves as a major stimulus for the induction of Hsp25 expression. These data provide evidence that flagellin is required for Salmonella-mediated induction of Hsp25 expression in intestinal epithelium.
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Ochocka, Anna-Maria, Marzena Czyzewska i Tadeusz Pawełczyk. "Expression in Escherichia coli of human ARHGAP6 gene and purification of His-tagged recombinant protein." Acta Biochimica Polonica 50, nr 1 (31.03.2003): 239–47. http://dx.doi.org/10.18388/abp.2003_3732.
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In this report we describe cloning and expression of human Rho GTPase activating protein (ARHGAP6) isoform 4 in Escherichia coli cells as a fusion protein with 6xHis. We cloned the ARHGAP6 cDNA into the bacterial expression vector pPROEX-1. Induction of the 6xHis-ARHGAP6 protein in BL21(DE3) and DH5alpha cells caused lysis of the cells irrespective of the kind of culture medium used. Successful expression of the fusion protein was obtained in the MC4100Deltaibp mutant strain lacking the small heat-shock proteins IbpA and IbpB. Reasonable yield was obtained when the cells were cultured in Terrific Broth + 1% glucose medium at 22 degrees C for 16 h. The optimal cell density for expression of soluble 6xHis-ARHGAP6 protein was at A(600) about 0.5. Under these conditions over 90% of the fusion protein was present in a soluble form. The 6xHis-ARHGAP6 protein was purified to near homogeneity by a two step procedure comprising chromatography on Ni-nitrilotriacetate and cation exchange columns. The expression system and purification procedure employed made it possible to obtain 1-2 mg of pure 6xHis-ARHGAP6 protein from 300 ml (1.5 g of cells) of E. coli culture.
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Tomoyasu, Toshifumi, Akiko Takaya, Tomomi Sasaki, Takahiro Nagase, Reiko Kikuno, Mizue Morioka i Tomoko Yamamoto. "A New Heat Shock Gene, agsA, Which Encodes a Small Chaperone Involved in Suppressing Protein Aggregation in Salmonella enterica Serovar Typhimurium". Journal of Bacteriology 185, nr 21 (1.11.2003): 6331–39. http://dx.doi.org/10.1128/jb.185.21.6331-6339.2003.
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ABSTRACT We discovered a novel small heat shock protein (sHsp) named AgsA (aggregation-suppressing protein) in the thermally aggregated fraction from a Salmonella enterica serovar Typhimurium dnaK-null strain. The −10 and −35 regions upstream of the transcriptional start site of the agsA gene are characteristic of σ32- and σ72-dependent promoters. AgsA was strongly induced by high temperatures. The similarity between AgsA and the other two sHsps of Salmonella serovar Typhimurium, IbpA and IbpB, is rather low (around 30% amino acid sequence identity). Phylogenetic analysis suggested that AgsA arose from an ancient gene duplication or amplification at an early evolutionary stage of gram-negative bacteria. Here we show that overproduction of AgsA partially complements the ΔdnaK52 thermosensitive phenotype and reduces the amount of heat-aggregated proteins in both ΔdnaK52 and ΔrpoH mutants of Escherichia coli. These data suggest that AgsA is an effective chaperone capable of preventing aggregation of nonnative proteins and maintaining them in a state competent for refolding in Salmonella serovar Typhimurium at high temperatures.
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Obuchowski, Igor, Artur Piróg, Milena Stolarska, Bartłomiej Tomiczek i Krzysztof Liberek. "Duplicate divergence of two bacterial small heat shock proteins reduces the demand for Hsp70 in refolding of substrates". PLOS Genetics 15, nr 10 (25.10.2019): e1008479. http://dx.doi.org/10.1371/journal.pgen.1008479.
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Narberhaus, Franz. "α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network". Microbiology and Molecular Biology Reviews 66, nr 1 (marzec 2002): 64–93. http://dx.doi.org/10.1128/mmbr.66.1.64-93.2002.
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SUMMARY α-Crystallins were originally recognized as proteins contributing to the transparency of the mammalian eye lens. Subsequently, they have been found in many, but not all, members of the Archaea, Bacteria, and Eucarya. Most members of the diverse α-crystallin family have four common structural and functional features: (i) a small monomeric molecular mass between 12 and 43 kDa; (ii) the formation of large oligomeric complexes; (iii) the presence of a moderately conserved central region, the so-called α-crystallin domain; and (iv) molecular chaperone activity. Since α-crystallins are induced by a temperature upshift in many organisms, they are often referred to as small heat shock proteins (sHsps) or, more accurately, α-Hsps. α-Crystallins are integrated into a highly flexible and synergistic multichaperone network evolved to secure protein quality control in the cell. Their chaperone activity is limited to the binding of unfolding intermediates in order to protect them from irreversible aggregation. Productive release and refolding of captured proteins into the native state requires close cooperation with other cellular chaperones. In addition, α-Hsps seem to play an important role in membrane stabilization. The review compiles information on the abundance, sequence conservation, regulation, structure, and function of α-Hsps with an emphasis on the microbial members of this chaperone family.
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Henderson, Brian, i Andrew C. R. Martin. "Protein moonlighting: a new factor in biology and medicine". Biochemical Society Transactions 42, nr 6 (17.11.2014): 1671–78. http://dx.doi.org/10.1042/bst20140273.
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The phenomenon of protein moonlighting was discovered in the 1980s and 1990s, and the current definition of what constitutes a moonlighting protein was provided at the end of the 1990s. Since this time, several hundred moonlighting proteins have been identified in all three domains of life, and the rate of discovery is accelerating as the importance of protein moonlighting in biology and medicine becomes apparent. The recent re-evaluation of the number of protein-coding genes in the human genome (approximately 19000) is one reason for believing that protein moonlighting may be a more general phenomenon than the current number of moonlighting proteins would suggest, and preliminary studies of the proportion of proteins that moonlight would concur with this hypothesis. Protein moonlighting could be one way of explaining the seemingly small number of proteins that are encoded in the human genome. It is emerging that moonlighting proteins can exhibit novel biological functions, thus extending the range of the human functional proteome. The several hundred moonlighting proteins so far discovered play important roles in many aspects of biology. For example, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), heat-shock protein 60 (Hsp60) and tRNA synthetases play a wide range of biological roles in eukaryotic cells, and a growing number of eukaryotic moonlighting proteins are recognized to play important roles in physiological processes such as sperm capacitation, implantation, immune regulation in pregnancy, blood coagulation, vascular regeneration and control of inflammation. The dark side of protein moonlighting finds a range of moonlighting proteins playing roles in various human diseases including cancer, cardiovascular disease, HIV and cystic fibrosis. However, some moonlighting proteins are being tested for their therapeutic potential, including immunoglobulin heavy-chain-binding protein (BiP), for rheumatoid arthritis, and Hsp90 for wound healing. In addition, it has emerged over the last 20 years that a large number of bacterial moonlighting proteins play important roles in bacteria–host interactions as virulence factors and are therefore potential therapeutic targets in bacterial infections. So as we progress in the 21st Century, it is likely that moonlighting proteins will be seen to play an increasingly important role in biology and medicine. It is hoped that some of the major unanswered questions, such as the mechanism of evolution of protein moonlighting, the structural biology of moonlighting proteins and their role in the systems biology of cellular systems can be addressed during this period.
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Macario, Alberto J. L., Marianne Lange, Birgitte K. Ahring i Everly Conway De Macario. "Stress Genes and Proteins in the Archaea". Microbiology and Molecular Biology Reviews 63, nr 4 (1.12.1999): 923–67. http://dx.doi.org/10.1128/mmbr.63.4.923-967.1999.
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SUMMARY The field covered in this review is new; the first sequence of a gene encoding the molecular chaperone Hsp70 and the first description of a chaperonin in the archaea were reported in 1991. These findings boosted research in other areas beyond the archaea that were directly relevant to bacteria and eukaryotes, for example, stress gene regulation, the structure-function relationship of the chaperonin complex, protein-based molecular phylogeny of organisms and eukaryotic-cell organelles, molecular biology and biochemistry of life in extreme environments, and stress tolerance at the cellular and molecular levels. In the last 8 years, archaeal stress genes and proteins belonging to the families Hsp70, Hsp60 (chaperonins), Hsp40(DnaJ), and small heat-shock proteins (sHsp) have been studied. The hsp70(dnaK), hsp40(dnaJ), and grpE genes (the chaperone machine) have been sequenced in seven, four, and two species, respectively, but their expression has been examined in detail only in the mesophilic methanogen Methanosarcina mazei S-6. The proteins possess markers typical of bacterial homologs but none of the signatures distinctive of eukaryotes. In contrast, gene expression and transcription initiation signals and factors are of the eucaryal type, which suggests a hybrid archaeal-bacterial complexion for the Hsp70 system. Another remarkable feature is that several archaeal species in different phylogenetic branches do not have the gene hsp70(dnaK), an evolutionary puzzle that raises the important question of what replaces the product of this gene, Hsp70(DnaK), in protein biogenesis and refolding and for stress resistance. Although archaea are prokaryotes like bacteria, their Hsp60 (chaperonin) family is of type (group) II, similar to that of the eukaryotic cytosol; however, unlike the latter, which has several different members, the archaeal chaperonin system usually includes only two (in some species one and in others possibly three) related subunits of ∼60 kDa. These form, in various combinations depending on the species, a large structure or chaperonin complex sometimes called the thermosome. This multimolecular assembly is similar to the bacterial chaperonin complex GroEL/S, but it is made of only the large, double-ring oligomers each with eight (or nine) subunits instead of seven as in the bacterial complex. Like Hsp70(DnaK), the archaeal chaperonin subunits are remarkable for their evolution, but for a different reason. Ubiquitous among archaea, the chaperonins show a pattern of recurrent gene duplication—hetero-oligomeric chaperonin complexes appear to have evolved several times independently. The stress response and stress tolerance in the archaea involve chaperones, chaperonins, other heat shock (stress) proteins including sHsp, thermoprotectants, the proteasome, as yet incompletely understood thermoresistant features of many molecules, and formation of multicellular structures. The latter structures include single- and mixed-species (bacterial-archaeal) types. Many questions remain unanswered, and the field offers extraordinary opportunities owing to the diversity, genetic makeup, and phylogenetic position of archaea and the variety of ecosystems they inhabit. Specific aspects that deserve investigation are elucidation of the mechanism of action of the chaperonin complex at different temperatures, identification of the partners and substitutes for the Hsp70 chaperone machine, analysis of protein folding and refolding in hyperthermophiles, and determination of the molecular mechanisms involved in stress gene regulation in archaeal species that thrive under widely different conditions (temperature, pH, osmolarity, and barometric pressure). These studies are now possible with uni- and multicellular archaeal models and are relevant to various areas of basic and applied research, including exploration and conquest of ecosystems inhospitable to humans and many mammals and plants.
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Fasnacht, Michel, Stefano Gallo, Puneet Sharma, Maximilian Himmelstoß, Patrick A. Limbach, Jessica Willi i Norbert Polacek. "Dynamic 23S rRNA modification ho5C2501 benefits Escherichia coli under oxidative stress". Nucleic Acids Research 50, nr 1 (14.12.2021): 473–89. http://dx.doi.org/10.1093/nar/gkab1224.
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Abstract Post-transcriptional modifications are added to ribosomal RNAs (rRNAs) to govern ribosome biogenesis and to fine-tune protein biosynthesis. In Escherichia coli and related bacteria, RlhA uniquely catalyzes formation of a 5-hydroxycytidine (ho5C) at position 2501 of 23S rRNA. However, the molecular and biological functions as well as the regulation of ho5C2501 modification remain unclear. We measured growth curves with the modification-deficient ΔrlhA strain and quantified the extent of the modification during different conditions by mass spectrometry and reverse transcription. The levels of ho5C2501 in E. coli ribosomes turned out to be highly dynamic and growth phase-dependent, with the most effective hydroxylation yields observed in the stationary phase. We demonstrated a direct effect of ho5C2501 on translation efficiencies in vitro and in vivo. High ho5C2501 levels reduced protein biosynthesis which however turned out to be beneficial for E. coli for adapting to oxidative stress. This functional advantage was small under optimal conditions or during heat or cold shock, but becomes pronounced in the presence of hydrogen peroxide. Taken together, these data provided first functional insights into the role of this unique 23S rRNA modification for ribosome functions and bacterial growth under oxidative stress.
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Paul, Deborupa, i Sanmitra Ghosh. "An overview of heat-stress response regulation in Gram-negative bacteria considering Escherichia coli as a model organism". Journal of Experimental Biology and Agricultural Sciences 10, nr 1 (28.02.2022): 190–200. http://dx.doi.org/10.18006/2022.10(1).190.200.
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Response to heat stress (HSR) is a key stress response for endurance in Escherichia coli mediated by transcriptional factor σ-32. Even though there has been extensive investigation on the contribution of proteins and chaperones in retaining protein stability in cells under stress conditions, limited information is available regarding the dynamic nature of mechanisms regulating the activity of the highly conserved heat shock proteins (Hsps). Several gene expression-based studies suggest the pivotal role of Hsp70 (DnaK) in the regulation of the expression of heat shock genes (Hsg). Direct interaction of Hsp70 with σ-32 may regulate this function in E. coli. Recent studies revealed that localization of σ-32 to the membrane interior by SRP-dependent pathway enables them to function appropriately in their role as regulators. The contributions of different cellular components including cell membrane remain unknown. Other cellular components or σ-32 interfere with polypeptides which could play a crucial role in cell survival. Sigma factor monitors and preserves outer membrane integrity of E. coli by stimulating the genes regulating outer membrane proteins (OMPs) and lipopolysaccharide (LPS) assemblage as well as through expression of small RNAs to down-regulate surplus unassembled OMPs. σ-E activity is regulated by the rate at which its membrane-encompassing anti-sigma factor, RseA is degraded. Mutations in rseA are reported to constitutively increase the sigma (E) activity that is validated at both genetic and biochemical levels. In this review, the basic mechanism of heat stress regulation in gram-negative bacteria has been elaborated using E. coli as a model organism.
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Liebscher, Markus, Günther Jahreis, Christian Lücke, Susanne Grabley, Satish Raina i Cordelia Schiene-Fischer. "Fatty Acyl Benzamido Antibacterials Based on Inhibition of DnaK-catalyzed Protein Folding". Journal of Biological Chemistry 282, nr 7 (14.12.2006): 4437–46. http://dx.doi.org/10.1074/jbc.m607667200.
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We have reported that the hsp70 chaperone DnaK from Escherichia coli might assist protein folding by catalyzing the cis/trans isomerization of secondary amide peptide bonds in unfolded or partially folded proteins. In this study a series of fatty acylated benzamido inhibitors of the cis/trans isomerase activity of DnaK was developed and tested for antibacterial effects in E. coli MC4100 cells. Nα-[Tetradecanoyl-(4-aminomethylbenzoyl)]-l-asparagine is the most effective antibacterial with a minimal inhibitory concentration of 100 ± 20 μg/ml. The compounds were shown to compete with fluorophore-labeled σ32-derived peptide for the peptide binding site of DnaK and to increase the fraction of aggregated proteins in heat-shocked bacteria. Despite its inability to serve as a folding helper in vivo a DnaK-inhibitor complex was still able to sequester an unfolded protein in vitro. Structure activity relationships revealed a distinct dependence of DnaK-assisted refolding of luciferase on the fatty acyl chain length, whereas the minimal inhibitory concentration was most sensitive to the structural nature of the benzamido core. We conclude that the isomerase activity of DnaK is a major survival factor in the heat shock response of bacteria and that small molecule inhibitors can lead to functional inactivation of DnaK and thus will display antibacterial activity.
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Garbe, T. R., N. S. Hibler i V. Deretic. "Response to Reactive Nitrogen Intermediates inMycobacterium tuberculosis: Induction of the 16-Kilodalton α-Crystallin Homolog by Exposure to Nitric Oxide Donors". Infection and Immunity 67, nr 1 (1.01.1999): 460–65. http://dx.doi.org/10.1128/iai.67.1.460-465.1999.
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ABSTRACT In contrast to the apparent paucity of Mycobacterium tuberculosis response to reactive oxygen intermediates, this organism has evolved a specific response to nitric oxide challenge. Exposure of M. tuberculosis to NO donors induces the synthesis of a set of polypeptides that have been collectively termed Nox. In this work, the most prominent Nox polypeptide, Nox16, was identified by immunoblotting and by N-terminal sequencing as the α-crystallin-related, 16-kDa small heat shock protein, sHsp16. A panel of chemically diverse donors of nitric oxide, with the exception of nitroprusside, induced sHsp16 (Nox16). Nitroprusside, a coordination complex of Fe2+ with a nitrosonium (NO+) ion, induced a 19-kDa polypeptide (Nox19) homologous to the nonheme bacterial ferritins. We conclude that the NO response in M. tuberculosis is dominated by increased synthesis of the α-crystallin homolog sHsp16, previously implicated in stationary-phase processes and found in this study to be a majorM. tuberculosis protein induced upon exposure to reactive nitrogen intermediates.
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El Demerdash, Hassan A. M., Knut J. Heller i Arnold Geis. "Application of the shsp Gene, Encoding a Small Heat Shock Protein, as a Food-Grade Selection Marker for Lactic Acid Bacteria". Applied and Environmental Microbiology 69, nr 8 (sierpień 2003): 4408–12. http://dx.doi.org/10.1128/aem.69.8.4408-4412.2003.
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ABSTRACT Plasmid pSt04 of Streptococcus thermophilus contains a gene encoding a protein with homology to small heat shock proteins (A. Geis, H. A. M. El Demerdash, and K. J. Heller, Plasmid 50:53-69, 2003). Strains cured from the shsp plasmids showed significantly reduced heat and acid resistance and a lower maximal growth temperature. Transformation of the cloned shsp gene into S. thermophilus St11 lacking a plasmid encoding shsp resulted in increased resistance to incubation at 60°C or pH 3.5 and in the ability to grow at 52°C. A food-grade cloning system for S. thermophilus, based on the plasmid-encoded shsp gene as a selection marker, was developed. This approach allowed selection after transfer of native and recombinant shsp plasmids into different S. thermophilus and Lactococcus lactis strains. Using a recombinant plasmid carrying an erythromycin resistance (Emr) gene in addition to shsp, we demonstrated that both markers are equally efficient in selecting for plasmid-bearing cells. The average transformation rates in S. thermophilus (when we were selecting for heat resistance) were determined to be 2.4 × 104 and 1.0 × 104 CFU/0.5 μg of DNA, with standard deviations of 0.54 × 104 and 0.32 × 104, for shsp and Emr selection, respectively. When we selected for pH resistance, the average transformation rates were determined to be 2.25 × 104 and 3.8 × 103 CFU/0.5 μg of DNA, with standard deviations of 0.63 × 104 and 3.48 × 103, for shsp and Emr selection, respectively. The applicability of shsp as a selection marker was further demonstrated by constructing S. thermophilus plasmid pHRM1 carrying the shsp gene as a selection marker and the restriction-modification genes of another S. thermophilus plasmid as a functional trait.
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Könen-Waisman, S., M. Fridkin i I. R. Cohen. "Self and foreign 60-kilodalton heat shock protein T cell epitope peptides serve as immunogenic carriers for a T cell-independent sugar antigen." Journal of Immunology 154, nr 11 (1.06.1995): 5977–85. http://dx.doi.org/10.4049/jimmunol.154.11.5977.
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Abstract Healthy individuals manifest natural T cell reactivity to epitopes of the 60-kDa heat shock protein (hsp60) of both self and bacterial origin. The present studies were done to learn whether defined peptides of hsp60 could function as T cell carrier epitopes for a poorly immunogenic T-independent capsular polysaccharide, the Vi Ag of Salmonella typhi. Homologous peptides were synthesized from the mouse self-hsp60 molecule (CP1m), from the closely related human hsp60 molecule (CP1h), and from the more distant Escherichia coli (CP1ec) and mycobacterial (CP1mt) hsp60 molecules. The peptides were conjugated to Vi and tested for their immunogenicity in BALB/c (H-2d) and H-2 congenic mice (H-2k and H-2b). We now report that the self-CP1m and cross-reactive CP1h peptides were as immunogenic as was the non-cross-reactive foreign CP1ec peptide. Small amounts of the CP1 peptide, even in PBS, sufficed to induce anti-Vi Abs of the IgG1 (T-dependent) isotype in naive mice. The carrier effect was associated with the ability of the peptides to bind to APC and to induce T cell proliferation. H-2d and H-2k mice, but not H-2b mice responded to CP1m/h and CP1ec. None of the mice responded to CP1mt. No signs of inflammation or autoimmune disease were detected. Thus, natural T cell autoimmunity exists and can be harnessed to provide T cell help for Ab production to a foreign bacterial molecule in a synthetic vaccine.
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Fu, Xinmiao, Wangwang Jiao i Zengyi Chang. "Phylogenetic and Biochemical Studies Reveal a Potential Evolutionary Origin of Small Heat Shock Proteins of Animals from Bacterial Class A". Journal of Molecular Evolution 62, nr 3 (10.02.2006): 257–66. http://dx.doi.org/10.1007/s00239-005-0076-5.
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Baldridge, Gerald D., Nicole Y. Burkhardt, Roderick F. Felsheim, Timothy J. Kurtti i Ulrike G. Munderloh. "Plasmids of the pRM/pRF Family Occur in Diverse Rickettsia Species". Applied and Environmental Microbiology 74, nr 3 (7.12.2007): 645–52. http://dx.doi.org/10.1128/aem.02262-07.
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ABSTRACT The recent discoveries of the pRF and pRM plasmids of Rickettsia felis and R. monacensis have contravened the long-held dogma that plasmids are not present in the bacterial genus Rickettsia (Rickettsiales; Rickettsiaceae). We report the existence of plasmids in R. helvetica, R. peacockii, R. amblyommii, and R. massiliae isolates from ixodid ticks and in an R. hoogstraalii isolate from an argasid tick. R. peacockii and four isolates of R. amblyommii from widely separated geographic locations contained plasmids that comigrated with pRM during pulsed-field gel electrophoresis and larger plasmids with mobilities similar to that of pRF. The R. peacockii plasmids were lost during long-term serial passage in cultured cells. R. montanensis did not contain a plasmid. Southern blots showed that sequences similar to those of a DnaA-like replication initiator protein, a small heat shock protein 2, and the Sca12 cell surface antigen genes on pRM and pRF were present on all of the plasmids except for that of R. massiliae, which lacked the heat shock gene and was the smallest of the plasmids. The R. hoogstraalii plasmid was most similar to pRM and contained apparent homologs of proline/betaine transporter and SpoT stringent response genes on pRM and pRF that were absent from the other plasmids. The R. hoogstraalii, R. helvetica, and R. amblyommii plasmids contained homologs of a pRM-carried gene similar to a Nitrobacter sp. helicase RecD/TraA gene, but none of the plasmids hybridized with a probe derived from a pRM-encoded gene similar to a Burkholderia sp. transposon resolvase gene.
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Murthy, Ashlesh K., Kelly Rae Keeler, Jennifer Do, Aravind Seetharaman, Kyle H. Ramsey, Mae Ciancio i weidang Li. "Tissue Specific Overexpression of Human Heat Shock Protein 70 in Mouse Oviduct Epithelium Reduces Chlamydia Induced Immunopathology". Journal of Immunology 200, nr 1_Supplement (1.05.2018): 114.20. http://dx.doi.org/10.4049/jimmunol.200.supp.114.20.
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Abstract Chlamydia trachomatis genital infections lead to severe immunopathological consequences in the upper genital tract (UGT), including pelvic inflammatory disease and infertility, in a small subset of infected women. Heat shock protein 70 (Hsp70) is an evolutionarily conserved stress-induced protein and has been shown to exhibit significant cytoprotective and immunoregulatory activities. However, the role of Hsp70 in genital chlamydial pathologies had not been examined. Hsp70 transgenic (Hsp70 Tg) mice were created by injecting a villin promoter-driven human Hsp70 targeting vector into C57BL/6 oocytes. The villin promoter is active only in the epithelium of the mouse oviduct but not in other parts of the female mouse genital tract. Female, 6-8 week old, Hsp70 Tg and non-transgenic (NTG) littermates were infected intravaginally with 5×104 IFU of C. muridarum. Vaginal chlamydial shedding, bacterial burden in the upper genital tract including oviducts and uterine horns, Chlamydia-specific IFN-γ, TNF-α, and IL-17 production, and serum anti-Chlamydia antibody levels were comparable between NTG and Hsp70 Tg mice. However, at day 80 after inoculation, the incidence and severity of pathology in oviducts, not neighboring uterine horns, was significantly reduced in Hsp70 Tg mice compared to NTG mice. Given the highly polymorphic nature of hsp-70 gene and associated susceptibility to various inflammatory conditions, and the occurrence of immunopathology in only a subset of Chlamydia-infected women, these results also underscore the need to further evaluate the role of hsp-70 in chlamydial immunopathogenesis in the female upper reproductive tract.
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Reilly, Natasha, Vitaliy Poylin, Michael Menconi, Andrew Onderdonk, Stig Bengmark i Per-Olof Hasselgren. "Probiotics potentiate IL-6 production in IL-1β-treated Caco-2 cells through a heat shock-dependent mechanism". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, nr 3 (wrzesień 2007): R1169—R1179. http://dx.doi.org/10.1152/ajpregu.00770.2006.
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IL-6 may exert anti-inflammatory and protective effects in intestinal mucosa and enterocytes. The influence of probiotics on mucosal and enterocyte IL-6 production is not known. We tested the hypothesis that the probiotic bacteria Lactobacillus paracasei and Lactobacillus plantarum regulate IL-6 production in intestinal epithelial cells. Cultured Caco-2 cells were treated with 1 ng/ml of IL-1β in the absence or presence of different concentrations of L. paracasei or L. plantarum followed by measurement of IL-6 production. The role of heat shock response was examined by determining the expression of heat shock protein 70 (hsp70) and hsp27, by downregulating their expression with small interfering RNA (siRNA), or by treating cells with quercetin. Treatment of the Caco-2 cells with IL-1β resulted in increased IL-6 production, confirming previous reports from this laboratory. Probiotics alone did not influence IL-6 production, but the addition of probitoics to IL-1β-treated cells resulted in a substantial augmentation of IL-6 production. Treatment of the Caco-2 cells with live L. paracasei increased cellular levels of hsp70 and hsp27 and the potentiating effect on IL-6 production was inhibited by quercetin and by hsp70 or hsp27 siRNA. Results suggest that probiotics may enhance IL-6 production in enterocytes subjected to an inflammatory stimulus and that this effect may, at least in part, be heat shock dependent.
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Inaba, Yuhei, Nobuhiro Ueno, Masatsugu Numata, Xiaorong Zhu, Jeannette S. Messer, David L. Boone, Mikihiro Fujiya, Yutaka Kohgo, Mark W. Musch i Eugene B. Chang. "Soluble bioactive microbial mediators regulate proteasomal degradation and autophagy to protect against inflammation-induced stress". American Journal of Physiology-Gastrointestinal and Liver Physiology 311, nr 4 (1.10.2016): G634—G647. http://dx.doi.org/10.1152/ajpgi.00092.2016.
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Bifidobacterium breve and other Gram-positive gut commensal microbes protect the gastrointestinal epithelium against inflammation-induced stress. However, the mechanisms whereby these bacteria accomplish this protection are poorly understood. In this study, we examined soluble factors derived from Bifidobacterium breve and their impact on the two major protein degradation systems within intestinal epithelial cells, proteasomes and autophagy. Conditioned media from gastrointestinal Gram-positive, but not Gram-negative, bacteria activated autophagy and increased expression of the autophagy proteins Atg5 and Atg7 along with the stress response protein heat shock protein 27. Specific examination of media conditioned by the Gram-positive bacterium Bifidobacterium breve (Bb-CM) showed that this microbe produces small molecules (<3 kDa) that increase expression of the autophagy proteins Atg5 and Atg7, activate autophagy, and inhibit proteasomal enzyme activity. Upregulation of autophagy by Bb-CM was mediated through MAP kinase signaling. In vitro studies using C2BBe1 cells silenced for Atg7 and in vivo studies using mice conditionally deficient in intestinal epithelial cell Atg7 showed that Bb-CM-induced cytoprotection is dependent on autophagy. Therefore, this work demonstrates that Gram-positive bacteria modify protein degradation programs within intestinal epithelial cells to promote their survival during stress. It also reveals the therapeutic potential of soluble molecules produced by these microbes for prevention and treatment of gastrointestinal disease.
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Darsonval, Maud, Tarek Msadek, Hervé Alexandre i Cosette Grandvalet. "The Antisense RNA Approach: a New Application forIn VivoInvestigation of the Stress Response of Oenococcus oeni, a Wine-Associated Lactic Acid Bacterium". Applied and Environmental Microbiology 82, nr 1 (9.10.2015): 18–26. http://dx.doi.org/10.1128/aem.02495-15.
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ABSTRACTOenococcus oeniis a wine-associated lactic acid bacterium mostly responsible for malolactic fermentation in wine. In wine,O. oenigrows in an environment hostile to bacterial growth (low pH, low temperature, and ethanol) that induces stress response mechanisms. To survive,O. oeniis known to set up transitional stress response mechanisms through the synthesis of heat stress proteins (HSPs) encoded by thehspgenes, notably a unique small HSP named Lo18. Despite the availability of the genome sequence, characterization ofO. oenigenes is limited, and little is known about thein vivorole of Lo18. Due to the lack of genetic tools forO. oeni, an efficient expression vector inO. oeniis still lacking, and deletion or inactivation of thehsp18gene is not presently practicable. As an alternative approach, with the goal of understanding the biological function of theO. oenihsp18genein vivo, we have developed an expression vector to produce antisense RNA targeting ofhsp18mRNA. Recombinant strains were exposed to multiple stresses inducinghsp18gene expression: heat shock and acid shock. We showed that antisense attenuation ofhsp18affectsO. oenisurvival under stress conditions. These results confirm the involvement of Lo18 in heat and acid tolerance ofO. oeni. Results of anisotropy experiments also confirm a membrane-protective role for Lo18, as previous observations had already suggested. This study describes a new, efficient tool to demonstrate the use of antisense technology for modulating gene expression inO. oeni.
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Gregory, Meredith, Emily Whiston, Norito Sugi, Coralynn Sack, Merideth C. Kamradt, Susan Heimer, Michael S. Gilmore i Bruce R. Ksander. "αB-crystallin protects the retina during S. aureus induced endophthalmitis (45.2)". Journal of Immunology 178, nr 1_Supplement (1.04.2007): S57. http://dx.doi.org/10.4049/jimmunol.178.supp.45.2.
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Abstract Purpose: Bacterial infections in the posterior of the eye (endophthalmitis) result in toxin-related retinal destruction. However, it is not known whether apoptosis contributes to infection pathology. We are investigating whether αB-crystallin protects retinal tissue during S. aureus endophthalmitis. αB-crystallin is an anti-apoptotic small heat shock protein constitutively expressed in the retina. We hypothesize that αB-crystallin protects the retina from apoptosis. Methods: 129S6/SvEv αB-crystallin KO and wild-type mice received intravitreal injections of 500 CFU S. aureus. Clinical examinations and ERGs (electroretinalgram) were performed at 24, 48, 72 and 96 hours. Eyes were analyzed histologically for apoptosis via TUNEL staining. Results: Infected WT mice had only low levels of apoptosis in the inner nuclear layer of the retina. By contrast, infected KO mice displayed: decreased ERG retinal function,increased retinal destruction via histopathology, andhigher levels of apoptosis in the ganglion cell, inner nuclear and outer nuclear retinal layers at 48 hours. Further experiments demonstrated that S. aureus triggers up-regulation of αB-crystallin in the retina andS. aureus produces a protease that cleaves and inactivates αB-crystallin in vitro and in vivo. Conclusions: Bacterial-induced apoptosis of the retina occurs during endophthalmitis. αB-crystallin is increased to prevent retinal apoptosis, while bacterial proteases are released in an attempt to invade the retina. NIH-EY-016145 (M Gregory)