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Sample records for kda heat shock

  1. The 29-kDa proteins phosphorylated ion thrombin-activated human platelets are forms of the estrogen receptor-related 27-kDa heat shock protein

    SciTech Connect

    Mendelsohn, M.E.; Yan Zhu; O'Neill, S. )

    1991-12-15

    Thrombin plays a critical role in platelet activation, hemostasis, and thrombosis. Cellular activation by thrombin leads to the phosphorylation of multiple proteins, most of which are unidentified. The authors have characterized several 29-kDa proteins that are rapidly phosphorylated following exposure of intact human platelets to thrombin. A murine monoclonal antibody raised to an unidentified estrogen receptor-related 29-kDa protein selectively recognized these proteins as well as a more basic, unphosphorylated 27-kDa protein. Cellular activation by thrombin led to a marked shift in the proportion of protein from the 27-kDa unphosphorylated form to the 29-kDa phosphoprotein species. Using this antibody, they isolated and sequenced a human cDNA clone encoding a protein that was identical to the mammalian 27-kDa heat shock protein (HSP27), a protein of uncertain function that is known to be phosphorylated to several forms and to be transcriptionally induced by estrogen. The 29-kDa proteins were confirmed to be phosphorylated forms of HSP27 by immunoprecipitation studies. Thus, the estrogen receptor-related protein is HSP27, and the three major 20-kDa proteins phosphorylated in thrombin-activated platelets are forms of HSP27. These data suggest a role for HSP27 in the signal transduction events of platelet activation.

  2. Detrimental Effect of Fungal 60-kDa Heat Shock Protein on Experimental Paracoccidioides brasiliensis Infection.

    PubMed

    Fernandes, Fabrício Freitas; Oliveira, Leandro Licursi de; Landgraf, Taise Natali; Peron, Gabriela; Costa, Marcelo Vieira; Coelho-Castelo, Arlete A M; Bonato, Vânia L D; Roque-Barreira, Maria-Cristina; Panunto-Castelo, Ademilson

    2016-01-01

    The genus Paracoccidioides comprises species of dimorphic fungi that cause paracoccidioidomycosis (PCM), a systemic disease prevalent in Latin America. Here, we investigated whether administration of native 60-kDa heat shock protein of P. brasiliensis (nPbHsp60) or its recombinant counterpart (rPbHsp60) affected the course of experimental PCM. Mice were subcutaneously injected with nPbHsp60 or rPbHsp60 emulsified in complete's Freund Adjuvant (CFA) at three weeks after intravenous injection of P. brasiliensis yeasts. Infected control mice were injected with CFA or isotonic saline solution alone. Thirty days after the nPbHsp60 or rPbHsp60 administration, mice showed remarkably increased fungal load, tissue inflammation, and granulomas in the lungs, liver, and spleen compared with control mice. Further, rPbHsp60 treatment (i) decreased the known protective effect of CFA against PCM and (ii) increased the concentrations of IL-17, TNF-α, IL-12, IFN-γ, IL-4, IL-10, and TGF-β in the lungs. Together, our results indicated that PbHsp60 induced a harmful immune response, exacerbated inflammation, and promoted fungal dissemination. Therefore, we propose that PbHsp60 contributes to the fungal pathogenesis. PMID:27598463

  3. The calmodulin-binding domain of the mouse 90-kDa heat shock protein.

    PubMed

    Minami, Y; Kawasaki, H; Suzuki, K; Yahara, I

    1993-05-01

    The mouse 90-kDa heat shock protein (HSP90) and Ca(2+)-calmodulin were cross-linked at an equimolar ratio using a carbodiimide zero-length cross-linker. To identify the calmodulin-binding domain(s) of HSP90, CNBr-cleaved peptide fragments of HSP90 were mixed with Ca(2+)-calmodulin and cross-linked. Amino acid sequence determination revealed that an HSP90 alpha-derived peptide starting at the 486th amino acid residue was contained in the cross-linked products, which contains a calmodulin-binding motif (from Lys500 to Ile520). A similar motif is present also in HSP90 beta (from Lys491 to Val511). The synthetic peptides corresponding to these putative calmodulin-binding sequences were found to be cross-linked with Ca(2+)-calmodulin and to prevent the cross-linking of HSP90 and Ca(2+)-calmodulin. Both HSP90 alpha and HSP90 beta bind Ca2+. The HSP90 peptides bind HSP90 and thereby inhibit the binding of Ca2+. In addition, the HSP90 peptides augment the self-oligomerization of HSP90 induced at elevated temperatures. These results suggest that the calmodulin-binding domain of HSP90 might interact with another part of the same molecule and that Ca(2+)-calmodulin might modulate the structure and function of HSP90 through abolishing the intramolecular interaction. PMID:8486648

  4. A Broad Set of Different Llama Antibodies Specific for a 16 kDa Heat Shock Protein of Mycobacterium tuberculosis

    PubMed Central

    Trilling, Anke K.; de Ronde, Hans; Noteboom, Linda; van Houwelingen, Adèle; Roelse, Margriet; Srivastava, Saurabh K.; Haasnoot, Willem; Jongsma, Maarten A.; Kolk, Arend; Zuilhof, Han; Beekwilder, Jules

    2011-01-01

    Background Recombinant antibodies are powerful tools in engineering of novel diagnostics. Due to the small size and stable nature of llama antibody domains selected antibodies can serve as a detection reagent in multiplexed and sensitive assays for M. tuberculosis. Methodology/Principal Findings Antibodies for Mycobacterium tuberculosis (M. tb) recognition were raised in Alpaca, and, by phage display, recombinant variable domains of heavy-chain antibodies (VHH) binding to M. tuberculosis antigens were isolated. Two phage display selection strategies were followed: one direct selection using semi-purified protein antigen, and a depletion strategy with lysates, aiming to avoid cross-reaction to other mycobacteria. Both panning methods selected a set of binders with widely differing complementarity determining regions. Selected recombinant VHHs were produced in E. coli and shown to bind immobilized lysate in direct Enzymelinked Immunosorbent Assay (ELISA) tests and soluble antigen by surface plasmon resonance (SPR) analysis. All tested VHHs were specific for tuberculosis-causing mycobacteria (M. tuberculosis, M. bovis) and exclusively recognized an immunodominant 16 kDa heat shock protein (hsp). The highest affinity VHH had a dissociation constant (KD) of 4×10−10 M. Conclusions/Significance A broad set of different llama antibodies specific for 16 kDa heat shock protein of M. tuberculosis is available. This protein is highly stable and abundant in M. tuberculosis. The VHH that detect this protein are applied in a robust SPR sensor for identification of tuberculosis-causing mycobacteria. PMID:22046343

  5. The mitochondrial 60-kDa heat shock protein in marine invertebrates: biochemical purification and molecular characterization

    PubMed Central

    Choresh, Omer; Loya, Yossi; Müller, Werner E.G.; Wiedenmann, Jörg; Azem, Abdussalam

    2004-01-01

    Sessile marine invertebrates undergo constant direct exposure to the surrounding environmental conditions, including local and global environmental fluctuations that may lead to fatal protein damage. Induction of heat shock proteins (Hsps) constitutes an important defense mechanism that protects these organisms from deleterious stress conditions. In a previous study, we reported the immunological detection of a 60-kDa Hsp (Hsp60) in the sea anemone Anemonia viridis (formerly called Anemonia sulcata) and studied its expression under a variety of stress conditions. In the present study, we show that the sponge Tetilla sp. from tidal habitats with a highly variable temperature regime is characterized by an increased level of Hsp60. Moreover, we show the expression of Hsp60 in various species among Porifera and Cnidaria, suggesting a general importance of this protein among marine invertebrates. We further cloned the hsp60 gene from A viridis, using a combination of conventional protein isolation methods and screening of a complementary deoxyribonucleic acid library by polymerase chain reaction. The cloned sequence (1764 bp) encodes for a protein of 62.8 kDa (588 amino acids). The 62.8-kDa protein, which contains an amino terminal extension that may serve as a mitochondrial targeting signal, shares a significant identity with mitochondrial Hsp60s from several animals but less identity with Hsp60s from either bacteria or plants. PMID:15270076

  6. A DOUBLE KNOCKOUT; A NOVEL APPROACH TO UNDERSTANDING STRESS-INDUCIBLE 70 KDA HEAT SHOCK PROTEINS (HSP70S) ON DEVELOPMENT AND REPRODUCTION

    EPA Science Inventory

    Heat and chemical toxicants which disrupt spermatogenesis and cause male infertility are thought to induce the expression of Hsp70-1 and 70-3, the major inducible heat shock proteins of the 70kDa family. Previous studies from several laboratories including our own have characteri...

  7. Multiple 40-kDa Heat-Shock Protein Chaperones Function in Tom70-dependent Mitochondrial Import

    PubMed Central

    Bhangoo, Melanie K.; Tzankov, Stefan; Fan, Anna C.Y.; Dejgaard, Kurt; Thomas, David Y.

    2007-01-01

    Mitochondrial preproteins that are imported via the translocase of the mitochondrial outer membrane (Tom)70 receptor are complexed with cytosolic chaperones before targeting to the mitochondrial outer membrane. The adenine nucleotide transporter (ANT) follows this pathway, and its purified mature form is identical to the preprotein. Purified ANT was reconstituted with chaperones in reticulocyte lysate, and bound proteins were identified by mass spectrometry. In addition to 70-kDa heat-shock cognate protein (Hsc70) and 90-kDa heat-shock protein (Hsp90), a specific subset of cochaperones were found, but no mitochondria-specific targeting factors were found. Interestingly, three different Hsp40-related J-domain proteins were identified: DJA1, DJA2, and DJA4. The DJAs bound preproteins to different extents through their C-terminal regions. DJA dominant-negative mutants lacking the N-terminal J-domains impaired mitochondrial import. The mutants blocked the binding of Hsc70 to preprotein, but with varying efficiency. The DJAs also showed significant differences in activation of the Hsc70 ATPase and Hsc70-dependent protein refolding. In HeLa cells, the DJAs increased new protein folding and mitochondrial import, although to different extents. No single DJA was superior to the others in all aspects, but each had a profile of partial specialization. The Hsp90 cochaperones p23 and Aha1 also regulated Hsp90–preprotein interactions. We suggest that multiple cochaperones with similar yet partially specialized properties cooperate in optimal chaperone–preprotein complexes. PMID:17596514

  8. Myocardial accumulation and localization of the inducible 70-kDa heat shock protein, Hsp70, following exercise

    PubMed Central

    Wolff, S.; Noble, E. G.

    2012-01-01

    Exercise increases the 70-kDa heat shock protein (Hsp70) in the myocardium, and this exercise-induced increase is associated with significantly improved cardiac recovery following insult. However, while heat shock has been shown to elevate Hsp70 primarily in the cardiac vasculature of the myocardium, the localization following exercise is unknown. Male Sprague-Dawley rats performed continuous treadmill running at 30 m/min for 60 min (2% incline) on either 1 or 5 consecutive days. At 30 min and 24 h following exercise, hearts were extirpated, and the left ventricle was isolated, OCT-cork mounted, and sectioned for immunofluorescent analysis. Whereas immunofluorescent analysis revealed little to no Hsp70 in control hearts and 30 min postexercise, the accumulation of Hsp70 24 h after a single exercise bout or 5 days of training was predominantly located in large blood vessels and, in particular, colocalized with a marker of smooth muscle. Furthermore, higher core temperatures attained during exercise led to more abundant accumulation in smaller vessels and the endothelium. It is concluded that the accumulation of myocardial Hsp70 following acute exercise predominantly occurs in a cell type-specific manner, such that changes in the cardiac vasculature account for much of the increase. This accumulation appears first in the smooth muscle of larger vessels and then increases in smaller vessels and the endothelium, as core temperature attained during exercise increases. This finding supports the observations after heat shock and further suggests that the vasculature is a primary target in exercise-induced cardioprotection. PMID:22773766

  9. A plastid-targeted heat shock cognate 70 kDa protein interacts with the Abutilon mosaic virus movement protein

    SciTech Connect

    Krenz, Bjoern; Windeisen, Volker; Wege, Christina; Jeske, Holger; Kleinow, Tatjana

    2010-05-25

    The movement protein (MP) of bipartite geminiviruses facilitates cell-to-cell as well as long-distance transport within plants and influences viral pathogenicity. Yeast two-hybrid assays identified a chaperone, the nuclear-encoded and plastid-targeted heat shock cognate 70 kDa protein (cpHSC70-1) of Arabidopsis thaliana, as a potential binding partner for the Abutilon mosaic virus (AbMV) MP. In planta, bimolecular fluorescence complementation (BiFC) analysis showed cpHSC70-1/MP complexes and MP homooligomers at the cell periphery and co-localized with chloroplasts. BiFC revealed cpHSC70-1 oligomers associated with chloroplasts, but also distributed at the cellular margin and in filaments arising from plastids reminiscent of stromules. Silencing the cpHSC70 gene of Nicotiana benthamiana using an AbMV DNA A-derived gene silencing vector induced minute white leaf areas, which indicate an effect on chloroplast stability. Although AbMV DNA accumulated within chlorotic spots, a spatial restriction of these occurred, suggesting a functional relevance of the MP-chaperone interaction for viral transport and symptom induction.

  10. Microsporidia, amitochondrial protists, possess a 70-kDa heat shock protein gene of mitochondrial evolutionary origin.

    PubMed

    Peyretaillade, E; Broussolle, V; Peyret, P; Méténier, G; Gouy, M; Vivarès, C P

    1998-06-01

    An intronless gene encoding a protein of 592 amino acid residues with similarity to 70-kDa heat shock proteins (HSP70s) has been cloned and sequenced from the amitochondrial protist Encephalitozoon cuniculi (phylum Microsporidia). Southern blot analyses show the presence of a single gene copy located on chromosome XI. The encoded protein exhibits an N-terminal hydrophobic leader sequence and two motifs shared by proteobacterial and mitochondrially expressed HSP70 homologs. Phylogenetic analysis using maximum likelihood and evolutionary distances place the E. cuniculi sequence in the cluster of mitochondrially expressed HSP70s, with a higher evolutionary rate than those of homologous sequences. Similar results were obtained after cloning a fragment of the homologous gene in the closely related species E. hellem. The presence of a nuclear targeting signal-like sequence supports a role of the Encephalitozoon HSP70 as a molecular chaperone of nuclear proteins. No evidence for cytosolic or endoplasmic reticulum forms of HSP70 was obtained through PCR amplification. These data suggest that Encephalitozoon species have evolved from an ancestor bearing mitochondria, which is in disagreement with the postulated presymbiotic origin of Microsporidia. The specific role and intracellular localization of the mitochondrial HSP70-like protein remain to be elucidated. PMID:9615449

  11. Cytoplasmic and extracellular expression of pharmaceutical-grade mycobacterial 65-kDa heat shock protein in Lactococcus lactis.

    PubMed

    de Azevedo, M S P; Rocha, C S; Electo, N; Pontes, D S; Molfetta, J B; Gonçalves, E D C; Azevedo, V; Silva, C L; Miyoshi, A

    2012-01-01

    Lactic acid bacteria (LAB) are an attractive and safe alternative for the expression of heterologous proteins, as they are nonpathogenic and endotoxin-free organisms. Lactococcus lactis, the LAB model organism, has been extensively employed in the biotechnology field for large-scale production of heterologous proteins, and its use as a "cell factory" has been widely studied. We have been particularly interested in the use of L. lactis for production of heat shock proteins (HSPs), which reportedly play important roles in the initiation of innate and adaptive immune responses. However, this activity has been questioned, as LPS contamination appears to be responsible for most, if not all, immunostimulatory activity of HSPs. In order to study the effect of pure HSPs on the immune system, we constructed recombinant L. lactis strains able to produce and properly address the Mycobacterium leprae 65-kDa HSP (Hsp65) to the cytoplasm or to the extracellular medium, using a xylose-induced expression system. Approximately 7 mg/L recombinant Hsp65 was secreted. Degradation products related to lactococcal HtrA activity were not observed, and the Limulus amebocyte lysate assay demonstrated that the amount of LPS in the recombinant Hsp65 preparations was 10-100 times lower than the permitted levels established by the U.S. Food and Drug Administration. These new L. lactis strains will allow investigation of the effects of M. leprae Hsp65 without the interference of LPS; consequently, they have potential for a variety of biotechnological, medical and therapeutic applications. PMID:22614283

  12. Modeling and Docking Studies on Novel Mutants (K71L and T204V) of the ATPase Domain of Human Heat Shock 70 kDa Protein 1

    PubMed Central

    Elengoe, Asita; Naser, Mohammed Abu; Hamdan, Salehhuddin

    2014-01-01

    The purpose of exploring protein interactions between human adenovirus and heat shock protein 70 is to exploit a potentially synergistic interaction to enhance anti-tumoral efficacy and decrease toxicity in cancer treatment. However, the protein interaction of Hsp70 with E1A32 kDa of human adenovirus serotype 5 remains to be elucidated. In this study, two residues of ATPase domain of human heat shock 70 kDa protein 1 (PDB: 1 HJO) were mutated. 3D mutant models (K71L and T204V) using PyMol software were then constructed. The structures were evaluated by PROCHECK, ProQ, ERRAT, Verify 3D and ProSA modules. All evidence suggests that all protein models are acceptable and of good quality. The E1A32 kDa motif was retrieved from UniProt (P03255), as well as subjected to docking interaction with NBD, K71L and T204V, using the Autodock 4.2 program. The best lowest binding energy value of −9.09 kcal/mol was selected for novel T204V. Moreover, the protein-ligand complex structures were validated by RMSD, RMSF, hydrogen bonds and salt bridge analysis. This revealed that the T204V-E1A32 kDa motif complex was the most stable among all three complex structures. This study provides information about the interaction between Hsp70 and the E1A32 kDa motif, which emphasizes future perspectives to design rational drugs and vaccines in cancer therapy. PMID:24758925

  13. The 59 kDa FK506-binding protein, a 90 kDa heat shock protein binding immunophilin (FKBP59-HBI), is associated with the nucleus, the cytoskeleton and mitotic apparatus.

    PubMed

    Perrot-Applanat, M; Cibert, C; Géraud, G; Renoir, J M; Baulieu, E E

    1995-05-01

    FKBP59-HBI, a 59 kDa FK506 binding protein which binds the 90 kDa heat shock protein hsp90 and thus is a heat shock protein binding immunophilin (HBI), was originally discovered in association with unliganded steroid receptors in their heat shock protein containing heterooligomer form. It belongs to a growing family including other FKBPs which bind the immunosuppressants FK506 and rapamycin, and cyclophilins which bind cyclosporin A, all having rotamase (peptidyl-prolyl cis-trans isomerase) activity which may be involved in protein folding. Targets for drug-immunophilin complexes have been mostly studied in vivo in T lymphocytes; however, immunophilins are present in all cell types, where their role and distribution are still unknown. Here we report the localization of FKBP59-HBI in various non lymphoid cells (mouse fibroblasts (L-929), monkey kidney cells (Cos-7), Madin-Darby canine kidney epithelial cells (MDCK), and mouse neuronal cells (GT1)). Two polyclonal antipeptide antibodies directed against the C-terminal end (amino acids 441-458) (Ab 173) or the sequence 182-201 (Ab 790) of the FKBP59-HBI were used in light and confocal laser immunofluorescence. FKBP59-HBI was found in the cytoplasm and nucleus of interphase cells. Specific immunofluorescence was much stronger in the cytoplasm than in the nucleus when using Ab 173, and stronger in the nucleus than in the cytoplasm with Ab 790. Detailed observations of L-cells, which have a particularly flat morphology, showed a punctate as well as a fibrous cytoskeletal staining in the cytoplasm using antibody 173, a result which suggests interactions of FKBP59-HBI with an organized network. Colocalization experiments (using antibodies against tubulin, vimentin or actin) and use of cytoskeletal-disrupting drugs revealed partial association of FKBP59-HBI with the microtubules. Western blot experiments confirmed that the protein was present in the subcellular fractions containing either 'soluble' proteins released from

  14. [Effects of noopept and cortexin on the behavior of matured rats treated with corticoliberin or 70-kDa heat shock proteins in early ontogeny].

    PubMed

    Shabanov, P D; Lebedev, A A; Stetsenko, V P; Lavrov, N V; Sablina, G V; Gudasheva, T A; Ostrovaskaia, R U

    2007-01-01

    Young Wistar rats aged 4 days were injected intraperitoneally with corticotropin releasing hormone (CRH), which is an agent activating the stress system, or 70-kDa heat shock proteins (HSP-70)--intracellular shaperons, possessing antistress properties. In grown adult rats aged 90-100 days, the effects of nootropic drugs noopept and cortexin (1 mg/kg, i.p.) were assessed. The activation of stress or antistress systems with CRH or HSP-70 significantly altered the drug action. The effects were different in males and females and depended on animal gender. The spectrum of pharmacological activity of noopept and cortexin changed: noopept demonstrated preferable psychoactivating and antiaggressive effects, whereas cortexin showed mild anxiolytic and antidepressant activity. It is suggested that the behavioral effects of nootropes depend on the conditions of the stress system formation in early ontogeny. PMID:17402584

  15. Characterization of the binding between a 70-kDa heat shock protein, HspA1A, and phosphoinositides.

    PubMed

    McCallister, Chelsea; Kdeiss, Brianna; Oliverio, Ryan; Nikolaidis, Nikolas

    2016-03-25

    HspA1A, a seventy-kilodalton heat shock protein, binds to specific anionic lipids and this interaction regulates important physiological phenomena like apoptosis, tumor growth, and lysosomal rescue. However, whether HspA1A binds to phosphoinositides has yet to be established and quantified. Therefore, in this study, we determined the binding affinity of HspA1A to several phosphoinositides and characterized five aspects of their molecular interaction. First, we established that HspA1A binds phosphatidylinositol monophosphates with higher affinity than di- and triphosphorylated inositides. Second, using high concentrations of potassium we found that HSPA1A embeds within the lipid bilayer of all phosphoinositides tested. However, the effects of the high salt concentrations were significantly different between the different phosphoinositides. Third, using calcium and reaction buffers equilibrated at different pH values we found that these differentially affected HspA1A-phosphoinositide binding, revealing a lipid-specific pattern of binding. Fourth, by assessing the binding properties of the two HspA1A domains, the nucleotide-binding domain and the substrate-binding domain, we determined that in most cases the full-length protein is necessary for binding to phosphoinositides. Fifth, by including in the reactions nucleotides and protein substrates we determined that they minimally and differentially affected phosphoinositide-binding. Collectively, these findings strongly suggest that the HspA1A-phosphoinositide binding is complex yet specific, is mediated by both electrostatic and hydrophobic interactions, is not related to the lipid-head charge, and depends on the physicochemical properties of the lipid. PMID:26923070

  16. The biochemical properties of the ATPase activity of a 70-kDa heat shock protein (Hsp70) are governed by the C-terminal domains

    PubMed Central

    Lopez-Buesa, Pascual; Pfund, Christine; Craig, Elizabeth A.

    1998-01-01

    The cytosolic 70-kDa heat shock proteins (Hsp70s), Ssa and Ssb, of Saccharomyces cerevisiae are functionally distinct. Here we report that the ATPase activities of these two classes of Hsp70s exhibit different kinetic properties. The Ssa ATPase has properties similar to those of other Hsp70s studied, such as DnaK and Hsc70. Ssb, however, has an unusually low steady-state affinity for ATP but a higher maximal velocity. In addition, the ATPase activity of Hsp70s, like that of Ssa1, depends on the addition of K+ whereas Ssb activity does not. Suprisingly, the isolated 44-kDa ATPase domain of Ssb has a Km and Vmax for ATP hydrolysis similar to those of Ssa, rather than those of full length Ssb. Analysis of Ssa/Ssb fusion proteins demonstrates that the Ssb peptide-binding domain fused to the Ssa ATPase domain generates an ATPase of relatively high activity and low steady-state affinity for ATP similar to that of native Ssb. Therefore, at least some of the biochemical differences between the ATPases of these two classes of Hsp70s are not intrinsic to the ATPase domain itself. The differential influence of the peptide-binding domain on the ATPase domain may, in part, explain the functional uniqueness of these two classes of Hsp70s. PMID:9860955

  17. The second metal-binding site of 70 kDa heat-shock protein is essential for ADP binding, ATP hydrolysis and ATP synthesis.

    PubMed Central

    Wu, Xueji; Yano, Mihiro; Washida, Hiroyo; Kido, Hiroshi

    2004-01-01

    The chaperone activity of Hsp70 (70 kDa heat-shock protein) in protein folding and its conformational switch, including oligomeric and monomeric interconversion, are regulated by the hydrolysis of ATP and the ATP-ADP exchange cycle. The crystal structure of human ATPase domain shows two metal-binding sites, the first for ATP binding and a second, in close proximity to the first, whose function remains unknown [Sriram, Osipiuk, Freeman, Morimoto and Joachimiak (1997) Structure 5, 403-414]. In this study, we have characterized the second metal-binding motif by site-directed mutagenesis and the kinetics of ATP and ADP binding, and found that the second metal-binding site, comprising a loop co-ordinated by His-227, Glu-231 and Asp-232, participates both in ATP hydrolysis and ATP-synthetic activities, in co-operation with the first metal-binding site. The first metal-binding site, a catalytic centre, is essential for ATP binding and the second site for ADP binding in the reactions of ATP hydrolysis and ATP synthesis. PMID:14664695

  18. A novel function for the 90 kDa heat-shock protein (Hsp90): facilitating nuclear export of 60 S ribosomal subunits.

    PubMed Central

    Schlatter, Harald; Langer, Thomas; Rosmus, Susann; Onneken, Marie-Luise; Fasold, Hugo

    2002-01-01

    Ribosomal subunits are assembled in the nucleus, and mature 40 S and 60 S subunits are exported stoichiometrically into the cytoplasm. The nuclear export of ribosomal subunits is a unidirectional, saturable and energy-dependent process. An in vitro assay for the nuclear export of 60 S ribosomal subunits involves the use of resealed nuclear envelopes. The export of ribosomal subunits from resealed nuclear envelopes is enhanced by cytoplasmic proteins. Here we present evidence that the export-promoting activity was due to the cytoplasmic 90 kDa heat-shock protein (Hsp90). Isolated, purified Hsp90 vastly enhanced the export of 60 S ribosomal subunits from resealed nuclear envelopes, while inhibition of Hsp90 function, either with the Hsp90-binding drug geldanamycin or with anti-Hsp90 antibodies, resulted in reduced release of 60 S ribosomal subunits. To confirm these findings under in vivo conditions, corresponding experiments were performed with Xenopus oocytes using microinjection techniques; the results obtained confirmed the findings obtained with resealed nuclear envelopes. These findings suggest that Hsp90 facilitates the nuclear export of 60 S ribosomal subunits, probably by chaperoning protein interactions during the export process. PMID:11879195

  19. The 70-kDa heat shock cognate protein (Hsc73) gene is enhanced by ovarian hormones in the ventromedial hypothalamus

    PubMed Central

    Krebs, Christopher J.; Jarvis, Erich D.; Pfaff, Donald W.

    1999-01-01

    Estrogen (E) and progesterone (P) orchestrate many cellular responses involved in female reproductive physiology, including reproductive behaviors. E- and P-binding neurons important for lordosis behavior have been located within the ventromedial hypothalamus (VMH), and several hormone-responsive genes have been observed there as well. In attempts to identify additional E- and P-responsive genes in the VMH that may contribute to sexual behaviors, we used the differential display mRNA screening technique. One of the genes identified encodes the 73-kDa heat shock cognate protein (Hsc73). Quantitative in situ hybridization analysis of brains from naturally cycling female rats revealed a significant increase in Hsc73 mRNA in the VMH and arcuate nucleus of animals during proestrus compared with those at diestrus-1. To confirm that these increases were steroid hormone dependent, we compared vehicle-treated ovariectomized females with ovariectomized females treated with estradiol benzoate and P. Northern analysis and in situ hybridizations showed that the Hsc73 gene is enhanced by E and P in the pituitary and subregions of the VMH. Incidentally, by examining the primary amino acid sequence of rat, human, and chicken progesterone receptors, we noticed that putative Hsc73 binding sites are conserved across species with similar sites existing in the androgen and glucocorticoid receptors. Together these findings suggest a possible mechanism through which E could influence the activities of progesterone, androgen, and glucocorticoid receptors, by enhancing the expression of Hsc73 in cells where these proteins colocalize. PMID:9990085

  20. The fusion of Toxoplasma gondii SAG1 vaccine candidate to Leishmania infantum heat shock protein 83-kDa improves expression levels in tobacco chloroplasts.

    PubMed

    Albarracín, Romina M; Becher, Melina Laguía; Farran, Inmaculada; Sander, Valeria A; Corigliano, Mariana G; Yácono, María L; Pariani, Sebastián; López, Edwin Sánchez; Veramendi, Jon; Clemente, Marina

    2015-05-01

    Chloroplast transformation technology has emerged as an alternative platform offering many advantages over nuclear transformation. SAG1 is the main surface antigen of the intracellular parasite Toxoplasma gondii and a promising candidate to produce an anti-T. gondii vaccine. The aim of this study was to investigate the expression of SAG1 using chloroplast transformation technology in tobacco plants. In order to improve expression in transplastomic plants, we also expressed the 90-kDa heat shock protein of Leishmania infantum (LiHsp83) as a carrier for the SAG1 antigen. SAG1 protein accumulation in transplastomic plants was approximately 0.1-0.2 μg per gram of fresh weight (FW). Fusion of SAG1 to LiHsp83 significantly increased the level of SAG1 accumulation in tobacco chloroplasts (by up to 500-fold). We also evaluated the functionality of the chLiHsp83-SAG1. Three human seropositive samples reacted with SAG1 expressed in transplastomic chLiHsp83-SAG1 plants. Oral immunization with chLiHsp83-SAG1 elicited a significant reduction of the cyst burden that correlated with an increase of SAG1-specific antibodies. We propose the fusion of foreign proteins to LiHsp83 as a novel strategy to increase the expression level of the recombinant proteins using chloroplast transformation technology, thus addressing one of the current challenges for this approach in antigen protein production. PMID:25823559

  1. Unique Peptide Substrate Binding Properties of 110-kDa Heat-shock Protein (Hsp110) Determine Its Distinct Chaperone Activity*

    PubMed Central

    Xu, Xinping; Sarbeng, Evans Boateng; Vorvis, Christina; Kumar, Divya Prasanna; Zhou, Lei; Liu, Qinglian

    2012-01-01

    The molecular chaperone 70-kDa heat-shock proteins (Hsp70s) play essential roles in maintaining protein homeostasis. Hsp110, an Hsp70 homolog, is highly efficient in preventing protein aggregation but lacks the hallmark folding activity seen in Hsp70s. To understand the mechanistic differences between these two chaperones, we first characterized the distinct peptide substrate binding properties of Hsp110s. In contrast to Hsp70s, Hsp110s prefer aromatic residues in their substrates, and the substrate binding and release exhibit remarkably fast kinetics. Sequence and structure comparison revealed significant differences in the two peptide-binding loops: the length and properties are switched. When we swapped these two loops in an Hsp70, the peptide binding properties of this mutant Hsp70 were converted to Hsp110-like, and more impressively, it functionally behaved like an Hsp110. Thus, the peptide substrate binding properties implemented in the peptide-binding loops may determine the chaperone activity differences between Hsp70s and Hsp110s. PMID:22157767

  2. Phosphorylation of the 27-kDa heat shock protein via p38 MAP kinase and MAPKAP kinase in smooth muscle.

    PubMed

    Larsen, J K; Yamboliev, I A; Weber, L A; Gerthoffer, W T

    1997-11-01

    The 27-kDa heat shock protein (HSP27) is expressed in a variety of tissues in the absence of stress and is thought to regulate actin filament dynamics, possibly by a phosphorylation/dephosphorylation mechanism. HSP27 has also been suggested to be involved in contraction of intestinal smooth muscle. We have investigated phosphorylation of HSP27 in airway smooth muscle in response to the muscarinic agonist carbachol. Carbachol increased 32P incorporation into canine tracheal HSP27 and induced a shift in the distribution of charge isoforms on two-dimensional gels to more acidic, phosphorylated forms. The canine HSP27 amino acid sequence includes three serine residues corresponding to sites in human HSP27 known to be phosphorylated by mitogen-activated protein kinase-activated protein (MAPKAP) kinase-2. To determine whether muscarinic receptors are coupled to a "stress response" pathway in smooth muscle culminating in phosphorylation of HSP27, we assayed MAPKAP kinase-2 activity and tyrosine phosphorylation of p38 mitogen-activated protein (MAP) kinase, the enzyme thought to activate MAPKAP kinase-2. Recombinant canine HSP27 expressed in Escherichia coli was a substrate for MAPKAP kinase-2 in vitro as well as a substrate for endogenous smooth muscle HSP27 kinase, which was activated by carbachol. Carbachol also increased tyrosine phosphorylation of p38 MAP kinase. SB-203580, an inhibitor of p38 MAP kinases, reduced activation of endogenous HSP27 kinase activity and blocked the shift in HSP27 charge isoforms to acidic forms. We suggest that HSP27 in airway smooth muscle, in addition to being a stress response protein, is phosphorylated by a receptor-initiated signaling cascade involving muscarinic receptors, tyrosine phosphorylation of p38 MAP kinase, and activation of MAPKAP kinase-2. PMID:9374719

  3. Age-Related Decrease in Heat Shock 70-kDa Protein 8 in Cerebrospinal Fluid Is Associated with Increased Oxidative Stress.

    PubMed

    Loeffler, David A; Klaver, Andrea C; Coffey, Mary P; Aasly, Jan O; LeWitt, Peter A

    2016-01-01

    Age-associated declines in protein homeostasis mechanisms ("proteostasis") are thought to contribute to age-related neurodegenerative disorders. The increased oxidative stress which occurs with aging can activate a key proteostatic process, chaperone-mediated autophagy. This study investigated age-related alteration in cerebrospinal fluid (CSF) concentrations of heat shock 70-kDa protein 8 (HSPA8), a molecular chaperone involved in proteostatic mechanisms including chaperone-mediated autophagy, and its associations with indicators of oxidative stress (8-hydroxy-2'-deoxyguanosine [8-OHdG] and 8-isoprostane) and total anti-oxidant capacity. We examined correlations between age, HSPA8, 8-OHdG, 8-isoprostane, and total antioxidant capacity (TAC) in CSF samples from 34 healthy subjects ranging from 20 to 75 years of age. Age was negatively associated with HSPA8 (ρ = -0.47; p = 0.005). An age-related increase in oxidative stress was indicated by a positive association between age and 8-OHdG (ρ = 0.61; p = 0.0001). HSPA8 was moderately negatively associated with 8-OHdG (ρ = -0.58; p = 0.0004). Age and HSPA8 were weakly associated with 8-isoprostane and TAC (range of ρ values: -0.15 to 0.16). Our findings in this exploratory study suggest that during healthy aging, CSF HSPA8 may decrease, perhaps due in part to an increase in oxidative stress. Our results also suggest that 8-OHdG may be more sensitive than 8-isoprostane for measuring oxidative stress in CSF. Further studies are indicated to determine if our findings can be replicated with a larger cohort, and if the age-related decrease in HSPA8 in CSF is reflected by a similar change in the brain. PMID:27507943

  4. Age-Related Decrease in Heat Shock 70-kDa Protein 8 in Cerebrospinal Fluid Is Associated with Increased Oxidative Stress

    PubMed Central

    Loeffler, David A.; Klaver, Andrea C.; Coffey, Mary P.; Aasly, Jan O.; LeWitt, Peter A.

    2016-01-01

    Age-associated declines in protein homeostasis mechanisms (“proteostasis”) are thought to contribute to age-related neurodegenerative disorders. The increased oxidative stress which occurs with aging can activate a key proteostatic process, chaperone-mediated autophagy. This study investigated age-related alteration in cerebrospinal fluid (CSF) concentrations of heat shock 70-kDa protein 8 (HSPA8), a molecular chaperone involved in proteostatic mechanisms including chaperone-mediated autophagy, and its associations with indicators of oxidative stress (8-hydroxy-2′-deoxyguanosine [8-OHdG] and 8-isoprostane) and total anti-oxidant capacity. We examined correlations between age, HSPA8, 8-OHdG, 8-isoprostane, and total antioxidant capacity (TAC) in CSF samples from 34 healthy subjects ranging from 20 to 75 years of age. Age was negatively associated with HSPA8 (ρ = –0.47; p = 0.005). An age-related increase in oxidative stress was indicated by a positive association between age and 8-OHdG (ρ = 0.61; p = 0.0001). HSPA8 was moderately negatively associated with 8-OHdG (ρ = –0.58; p = 0.0004). Age and HSPA8 were weakly associated with 8-isoprostane and TAC (range of ρ values: –0.15 to 0.16). Our findings in this exploratory study suggest that during healthy aging, CSF HSPA8 may decrease, perhaps due in part to an increase in oxidative stress. Our results also suggest that 8-OHdG may be more sensitive than 8-isoprostane for measuring oxidative stress in CSF. Further studies are indicated to determine if our findings can be replicated with a larger cohort, and if the age-related decrease in HSPA8 in CSF is reflected by a similar change in the brain. PMID:27507943

  5. Distinct functions of the 90 kDa heat-shock protein (hsp90) in oestrogen and mineralocorticosteroid receptor activity: effects of hsp90 deletion mutants.

    PubMed

    Binart, N; Lombès, M; Baulieu, E E

    1995-11-01

    Recent studies have confirmed that the 90 kDa heat-shock protein (hsp90) interacts both in vitro and in vivo with steroid receptors, encouraging further detailed physicochemical and functional analysis of its chaperone role. Thus, to explore the relationship between hsp90 and receptors, the baculovirus system was used to overexpress the chick hsp90 alpha (chsp90) along with the chick oestradiol receptor (cER) or the human mineralocorticosteroid receptor (hMR). These receptors were able to form 9 S complexes with chsp90, demonstrating the association of the co-expressed recombinant proteins. Three mutants of chsp90 (delta A, delta B and delta Z) have been created by deletion of the A (residues 221-290) and B (530-581) regions, rich in charged amino acids, and the Z (392-419) region, a putative leucine zipper. After co-expression, anti-receptor antibodies immunoprecipitated the cER or hMR complexed with the wild-type chsp90, the delta B or the delta Z mutant, but not with the delta A chsp90, indicating that deletion of the A region of chsp90 leads to a lack of interaction with these receptors. The hormone binding capacity of the cER was unaffected after its co-expression with each of the three mutants. In contrast, the hMR co-expressed with the delta B mutant failed to bind aldosterone, a finding confirmed in vivo by the absence of hormone-induced hMR nuclear translocation. Thus the B region is required for high-affinity ligand binding by the hMR. Our results suggest that the A region (but not the B or Z regions) is involved in binding of chsp90 to the cER and hMR, while the B region is essential for hormone binding by the hMR, consistent with a chaperone function for hsp90. PMID:7487934

  6. Transcription of the Neurospora crassa 70-kDa class heat shock protein genes is modulated in response to extracellular pH changes

    PubMed Central

    Squina, Fabio M.; Leal, Juliana; Cipriano, Vivian T. F.; Martinez-Rossi, Nilce M.

    2009-01-01

    Heat shock proteins belong to a conserved superfamily of molecular chaperones found in prokaryotes and eukaryotes. These proteins are linked to a myriad of physiological functions. In this study, we show that the N. crassa hsp70-1 (NCU09602.3) and hsp70-2 (NCU08693.3) genes are preferentially expressed in an acidic milieu after 15 h of cell growth in sufficient phosphate at 30°C. No significant accumulation of these transcripts was detected at alkaline pH values. Both genes accumulated to a high level in mycelia that were incubated for 1 h at 45°C, regardless of the phosphate concentration and extracellular pH changes. Transcription of the hsp70-1 and hsp70-2 genes was dependent on the pacC+ background in mycelia cultured under optimal growth conditions or at 45°C. The pacC gene encodes a Zn-finger transcription factor that is involved in the regulation of gene expression by pH. Heat shock induction of these two hsp genes in mycelia incubated in low-phosphate medium was almost not altered in the nuc-1− background under both acidic and alkaline pH conditions. The NUC-1 transcriptional regulator is involved in the derepression of nucleases, phosphatases, and transporters that are necessary for fulfilling the cell's phosphate requirements. Transcription of the hsp70-3 (NCU01499.3) gene followed a different pattern of induction—the gene was depressed under insufficient phosphate conditions but was apparently unaffected by alkalinization of the culture medium. Moreover, this gene was not induced by heat shock. These results reveal novel aspects of the heat-sensing network of N. crassa. PMID:19618296

  7. The 90 kDa heat-shock protein (hsp90) modulates the binding of the oestrogen receptor to its cognate DNA.

    PubMed

    Sabbah, M; Radanyi, C; Redeuilh, G; Baulieu, E E

    1996-02-15

    The role of heat-shock protein 90 (hsp90) in the regulation of the oestrogen receptor (ER) function is less well understood than for other steroid-hormone receptors because hsp90 is not involved in the stabilization or induction of a high-affinity ligand-binding state of ER nor in the inhibition of receptor dimerization. Electrophoretic mobility-shift assays, using purified ER and hsp90, were employed to investigate directly the effect of hsp90 on the ability of ER to bind to the oestrogen-response element (ERE) from the vitellogenin A2 gene. Contrary to models in which hsp90 binds to and passively inactivates steroid-hormone receptors, our studies show that the binding of ER to ERE is inversely dependent on the relative concentration of hsp90. Exposure of purified ER-hsp90 complexes to ERE led to the dissociation of hsp90 and concomitant specific binding of ER to ERE. We demonstrate that the amount of ER-ERE complex decreased with increasing concentrations of hsp90. Furthermore hsp90 dissociated preformed high-affinity ER-ERE complexes. Kinetic dissociation experiments indicate the hsp90 acts in a dynamic and specific process rather than by simple trapping of ER owing to its inherent off-rate. The receptor released from the ERE-bound state by hsp90 was recovered associated with hsp90 and was able to rebind to ERE. These results indicate that hsp90 does not suppress ER function merely by steric hindrance. On the basis of these results and others, we propose that, in vivo, hsp90 may play a dual role in ER function: (i) at a physiological temperature, hsp90 stabilizes an active form of the receptor in accordance with its general molecular chaperone role; (ii) at elevated temperatures or under other environmental stress, the increased cellular concentration of hsp90 negatively interferes with ER-dependent transcription, in accordance with the inhibition of gene transcription attributed to hsp90 after heat shock. PMID:8660284

  8. Distribution of lactoferrin and 60/65 kDa heat shock protein in normal and inflamed human intestine and liver.

    PubMed Central

    Peen, E; Eneström, S; Skogh, T

    1996-01-01

    Immunisation against the mycobacterial heat shock protein (hsp-65) has been proposed to lead to production of autoantibodies against human lactoferrin. Such antibodies occur in ulcerative colitis and in primary sclerosing cholangitis. This study analysed the distribution of hsp-65 and lactoferrin in biopsy specimens from patients with inflammatory bowel disease and primary sclerosing cholangitis and studied whether immunisation against mycobacterial hsp-65 resulted in production of antilactoferrin antibodies and vice versa. Polyclonal rabbit antihuman lactoferrin and monoclonal mouse anti-hsp-65 (ML30) were used for immunohistochemistry on biopsy specimens from patients with inflammatory bowel disease and primary sclerosing cholangitis. Rats were immunised against human lactoferrin and mycobacterial hsp-65 respectively. Antibody measurements were done by enzyme immunosorbent assays. It was found that lactoferrin and hsp-60/65 were not codistributed. Lactoferrin was found on vascular endothelium and in nonparenchymal liver cells both in inflamed and uninflamed tissues, but only in the hepatocytes of inflamed liver. ML30 reactivity was not inhibited by antilactoferrin antibodies. Rat anti-hsp-65 serum had no detectable antilactoferrin antibodies. In conclusion, antilactoferrin antibodies probably do not arise by immunisation against mycobacterial hsp-65. Both nonparenchymal cells and hepatocytes probably participate in clearance of lactoferrin. Endothelial exposure of lactoferrin may have pathogenic implications in diseases with antilactoferrin autoantibodies. Images Figure 1 Figure 2 PMID:8566841

  9. 70-kDa heat shock protein coated magnetic nanocarriers as a nanovaccine for induction of anti-tumor immune response in experimental glioma.

    PubMed

    Shevtsov, Maxim A; Nikolaev, Boris P; Yakovleva, Liudmila Y; Parr, Marina A; Marchenko, Yaroslav Y; Eliseev, Igor; Yudenko, Anna; Dobrodumov, Anatolii V; Zlobina, Olga; Zhakhov, Alexander; Ischenko, Alexander M; Pitkin, Emil; Multhoff, Gabriele

    2015-12-28

    Nanovaccines based on superparamagnetic iron oxide nanoparticles (SPIONs) provide a novel approach to induce the humoral and cell-based immune system to fight cancer. Herein, we increased the immunostimulatory capacity of SPIONs by coating them with recombinant heat shock protein 70 (Hsp70) which is known to chaperone antigenic peptides. After binding, Hsp70-SPIONs deliver immunogenic peptides from tumor lysates to dendritiс cells (DCs) and thus stimulate a tumor-specific, CD8+ cytotoxic T cell response. We could show that binding activity of Hsp70-SPIONs to the substrate-binding domain (SBD) is highly dependent on the ATPase activity of its nucleotide-binding domain NBD), as shown by (31)P NMR spectroscopy. Immunization of C6 glioma-bearing rats with DCs pulsed with Hsp70-SPIONs and tumor lysates resulted in a delayed tumor progression (as measured by MRI) and an increased overall survival. In parallel an increased IFNγ secretion were detected in the serum of these animals and immunohistological analysis of subsequent cryosections of the glioma revealed an enhanced infiltration of memory CD45RO+ and cytotoxic CD8+ T cells. Taken together the study demonstrates that magnetic nanocarriers such as SPIONs coated with Hsp70 can be applied as a platform for boosting anti-cancer immune responses. PMID:26522072

  10. Brain tumor magnetic targeting and biodistribution of superparamagnetic iron oxide nanoparticles linked with 70-kDa heat shock protein study by nonlinear longitudinal response

    NASA Astrophysics Data System (ADS)

    Shevtsov, Maxim A.; Nikolaev, Boris P.; Ryzhov, Vyacheslav A.; Yakovleva, Ludmila Y.; Dobrodumov, Anatolii V.; Marchenko, Yaroslav Y.; Margulis, Boris A.; Pitkin, Emil; Guzhova, Irina V.

    2015-08-01

    Brain tumor targeting efficiency and biodistribution of the superparamagnetic nanoparticles conjugated with heat shock protein Hsp70 (SPION-Hsp70) were evaluated in experimental glioma model. Synthesized conjugates were characterized using the method of longitudinal nonlinear response of magnetic nanoparticles to a weak ac magnetic field with measurements of second harmonic of magnetization (NLR-M2). Cellular interaction of magnetic conjugates was analyzed in 9L glioma cell culture. The biodistribution of the nanoparticles and their accumulation in tumors was assessed by the latter approach as well. The efficacy of Hsp70-conjugates for contrast enhancement in the orthotopic model of 9L glioma was assessed by MR imaging (11 T). Magnetic nanoparticles conjugated with Hsp70 had the relaxivity properties of the MR-negative contrast agents. Morphological observation and cell viability test demonstrated good biocompatibility of Hsp70-conjugates. Analysis of the T2-weighted MR scans in tumor-bearing rats demonstrated the high efficacy of Hsp70-conjugates in contrast enhancement of the glioma in comparison to non-conjugated nanoparticles. High contrast enhancement of the glioma was provided by the accumulation of the SPION-Hsp70 particles in the glioma tissue (as shown by the histological assay). Biodistribution analysis by NLR-M2 measurements evidenced the many-fold increase (~40) in the tumor-to-normal brain uptake ratio in the Hsp70-conjugates treated animals. Biodistribution pattern of Hsp70-decorated nanoparticles differed from that of non-conjugated SPIONs. Coating of the magnetic nanoparticles with Hsp70 protein enhances the tumor-targeting ability of the conjugates that could be applied in the MR imaging of the malignant brain tumors.

  11. Antibodies directed to the gram-negative bacterium Neisseria gonorrhoeae cross-react with the 60 kDa heat shock protein and lead to impaired neurite outgrowth in NTera2/D1 cells.

    PubMed

    Reuss, B; Asif, A R

    2014-09-01

    Children of mothers with prenatal gonococcal infections are of increased risk to develop schizophrenic psychosis in later life. The present study hypothesizes an autoimmune mechanism for this, investigating interactions of a commercial rabbit antiserum directed to Neisseria gonorrhoeae (α-NG) with human NTera2/D1 cells, an established in vitro model for human neuronal differentiation. Immunocytochemistry demonstrated α-NG to label antigens on an intracellular organelle, which by Western blot analysis showed a molecular weight shortly below 72 kDa. An antiserum directed to Neisseria meningitidis (α-NM) reacts with an antigen shortly below 95 kDa, confirming antibody specificity of these interactions. Two-dimensional gel electrophoresis and partial Western transfer, allowed to localize an α-NG reactive protein spot which was identified by LC-Q-TOF MS/MS analysis as mitochondrial heat shock protein Hsp60. This was confirmed by Western blot analysis of α-NG immunoreactivity with a commercial Hsp60 protein sample, with which α-NM failed to interact. Finally, analysis of neurite outgrowth in retinoic acid-stimulated differentiating NTera2-D1 cells, demonstrates that α-NG but not α-NM treatment reduces neurite length. These results demonstrate that α-NG can interact with Hsp60 in vitro, whereas pathogenetic relevance of this interaction for psychotic symptomatology remains to be clarified. PMID:24577885

  12. Comparative inhibition by hard and soft metal ions of steroid-binding capacity of renal mineralocorticoid receptor cross-linked to the 90-kDa heat-shock protein heterocomplex.

    PubMed Central

    Galigniana, M D; Piwien-Pilipuk, G

    1999-01-01

    We analysed the inhibitory effects in vitro and in vivo of several metal ions on aldosterone binding to the rat kidney mineralocorticoid receptor with the purpose of assessing possible toxic effects of those ions on sodium retention, as well as to obtain information on receptor structural requirements for ligand binding. For the assays in vitro, the inhibitory effects of 20 metal ions were analysed on steroid-binding capacity for renal receptor cross-linked to 90-kDa heat-shock protein (hsp90) by pretreatment with dimethyl pimelimidate. Cross-linking prevented the artifactual dissociation of hsp90 (and, consequently, the loss of steroid binding) from the mineralocorticoid receptor due to the presence of high concentrations of salt in the incubation medium. Cross-linked heterocomplex showed no difference in ligand specificity and affinity with respect to native receptor, but increased stability upon thermal- or ionic-strength-induced destabilization was observed. Treatments in vitro with metal ions in the range 10(-8)-10(-1) M resulted in a differential inhibitory effect for each particular ion on aldosterone binding. Using the negative logarithm of metal concentration for 50% inhibition, the ions could be correlated with their Klopman hardness constants. The analysis of this relationship led us to postulate three types of reaction: with thiol, imidazole and carboxyl groups. The essential role played by these residues in steroid binding was confirmed by chemical modification of cysteines with dithionitrobenzoic acid, histidines with diethyl pyrocarbonate and acidic amino acids with Woodward's reagent (N-ethyl-5-phenylisoxazolium-3'-sulphonate). Importantly, the toxic effects of some metal ions were also observed by treatments in vivo of adrenalectomized rats on both steroid-binding capacity and aldosterone-dependent sodium-retaining properties. We suggest that those amino acid residues are involved in the activation process of the mineralocorticoid receptor upon

  13. Suppression of heat-induced hsp70 expression by the 70-kDa subunit of the human Ku autoantigen.

    PubMed

    Li, G C; Yang, S H; Kim, D; Nussenzweig, A; Ouyang, H; Wei, J; Burgman, P; Li, L

    1995-05-01

    Expression of the 70-kDa polypeptide of human Ku autoantigen in rat cells is shown to suppress specifically the induction of hsp70 upon heat shock. Thermal induction of other heat shock proteins is not significantly affected, nor is the state of phosphorylation or the DNA-binding ability of the heat shock transcription factor HSF1. These findings support a model in which hsp70 gene expression is controlled by a second regulatory factor in addition to the positive activator HSF1. The Ku autoantigen, or a protein closely related to it, is likely to be involved in the regulation of hsp70 expression. PMID:7753835

  14. A constitutive 70 kDa heat-shock protein is localized on the fibres of spindles and asters at metaphase in an ATP-dependent manner: a new chaperone role is proposed.

    PubMed

    Agueli, C; Geraci, F; Giudice, G; Chimenti, L; Cascino, D; Sconzo, G

    2001-12-01

    In the present study, double immunofluorescence and immunoblot analysis have been used to show that centrosomes, isolated from Paracentrotus lividus sea urchin embryos at the first mitotic metaphase, contain the constitutive chaperone, heat-shock protein (HSP) 70. More specifically, we demonstrate that centrosomes contain only the HSP70-d isoform, which is one of the four isoforms identified in P. lividus. We also provide evidence that p34(cell division control kinase-2) and t complex polypeptide-1 (TCP-1) alpha, a subunit of the TCP-1 complex, are localized on the centrosomes. Furthermore, inhibition of TCP-1 in vivo, via microinjecting an anti-(TCP-1 alpha) antibody into P. lividus eggs before fertilization, either impaired mitosis or induced severe malformations in more than 50% of embryos. In addition, we have isolated the whole mitotic apparatus and shown that HSP70 localizes on the fibres of spindles and asters, and binds them in an ATP-dependent manner. These observations suggest that HSP70 has a chaperone role in assisting the TCP-1 complex in tubulin folding, when localized on centrosomes, and during the assembling and disassembling of the mitotic apparatus, when localized on the fibres of spindles and asters. PMID:11716770

  15. A constitutive 70 kDa heat-shock protein is localized on the fibres of spindles and asters at metaphase in an ATP-dependent manner: a new chaperone role is proposed.

    PubMed Central

    Agueli, C; Geraci, F; Giudice, G; Chimenti, L; Cascino, D; Sconzo, G

    2001-01-01

    In the present study, double immunofluorescence and immunoblot analysis have been used to show that centrosomes, isolated from Paracentrotus lividus sea urchin embryos at the first mitotic metaphase, contain the constitutive chaperone, heat-shock protein (HSP) 70. More specifically, we demonstrate that centrosomes contain only the HSP70-d isoform, which is one of the four isoforms identified in P. lividus. We also provide evidence that p34(cell division control kinase-2) and t complex polypeptide-1 (TCP-1) alpha, a subunit of the TCP-1 complex, are localized on the centrosomes. Furthermore, inhibition of TCP-1 in vivo, via microinjecting an anti-(TCP-1 alpha) antibody into P. lividus eggs before fertilization, either impaired mitosis or induced severe malformations in more than 50% of embryos. In addition, we have isolated the whole mitotic apparatus and shown that HSP70 localizes on the fibres of spindles and asters, and binds them in an ATP-dependent manner. These observations suggest that HSP70 has a chaperone role in assisting the TCP-1 complex in tubulin folding, when localized on centrosomes, and during the assembling and disassembling of the mitotic apparatus, when localized on the fibres of spindles and asters. PMID:11716770

  16. Toxoplasma gondii 70 kDa Heat Shock Protein: Systemic Detection Is Associated with the Death of the Parasites by the Immune Response and Its Increased Expression in the Brain Is Associated with Parasite Replication

    PubMed Central

    Barenco, Paulo Victor Czarnewski; Lourenço, Elaine Vicente; Cunha-Júnior, Jair Pereira; Almeida, Karine Cristine; Roque-Barreira, Maria Cristina; Silva, Deise Aparecida Oliveira; Araújo, Ester Cristina Borges; Coutinho, Loyane Bertagnolli; Oliveira, Mário Cézar; Mineo, Tiago Wilson Patriarca; Mineo, José Roberto; Silva, Neide Maria

    2014-01-01

    The heat shock protein of Toxoplasma gondii (TgHSP70) is a parasite virulence factor that is expressed during T. gondii stage conversion. To verify the effect of dexamethasone (DXM)-induced infection reactivation in the TgHSP70-specific humoral immune response and the presence of the protein in the mouse brain, we produced recombinant TgHSP70 and anti-TgHSP70 IgY antibodies to detect the protein, the specific antibody and levels of immune complexes (ICs) systemically, as well as the protein in the brain of resistant (BALB/c) and susceptible (C57BL/6) mice. It was observed higher TgHSP70-specific antibody titers in serum samples of BALB/c compared with C57BL/6 mice. However, the susceptible mice presented the highest levels of TgHSP70 systemically and no detection of specific ICs. The DXM treatment induced increased parasitism and lower inflammatory changes in the brain of C57BL/6, but did not interfere with the cerebral parasitism in BALB/c mice. Additionally, DXM treatment decreased the serological TgHSP70 concentration in both mouse lineages. C57BL/6 mice presented high expression of TgHSP70 in the brain with the progression of infection and under DXM treatment. Taken together, these data indicate that the TgHSP70 release into the bloodstream depends on the death of the parasites mediated by the host immune response, whereas the increased TgHSP70 expression in the brain depends on the multiplication rate of the parasite. PMID:24801069

  17. Suppression of heat-induced hsp70 expression by the 70-kDa subunit of the human Ku autoantigen.

    PubMed Central

    Li, G C; Yang, S H; Kim, D; Nussenzweig, A; Ouyang, H; Wei, J; Burgman, P; Li, L

    1995-01-01

    Expression of the 70-kDa polypeptide of human Ku autoantigen in rat cells is shown to suppress specifically the induction of hsp70 upon heat shock. Thermal induction of other heat shock proteins is not significantly affected, nor is the state of phosphorylation or the DNA-binding ability of the heat shock transcription factor HSF1. These findings support a model in which hsp70 gene expression is controlled by a second regulatory factor in addition to the positive activator HSF1. The Ku autoantigen, or a protein closely related to it, is likely to be involved in the regulation of hsp70 expression. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7753835

  18. Heat shock protein hsp70 accelerates the recovery of heat-shocked mammalian cells through its modulation of heat shock transcription factor HSF1.

    PubMed Central

    Kim, D; Ouyang, H; Li, G C

    1995-01-01

    The role of mammalian 70-kDa heat shock protein (hsp70) in regulating cellular response to heat shock was examined by using three closely related rat cells: control Rat-1 cells, thermotolerant Rat-1 (TT Rat-1) cells, and heat-resistant M21 cells, a derivative of Rat-1 cells that constitutively overexpress human hsp70. In all these cells, after a prescribed heat shock, the level of the phosphorylated form of heat shock transcription factor HSF1 and that of HSF1 capable of binding to its cognitive DNA sequence heat shock element (HSE) exhibit similar time dependence. The amount of a constitutive HSE-binding activity (CHBA), on the other hand, inversely correlates with those of the two aforementioned forms of HSF1. The recovery kinetics from heat shock are different for the three cell lines, with the thermal-resistant TT Rat-1 and M21 cells showing faster recovery in terms of the state of phosphorylation of HSF1 and its ability to bind HSE or in terms of the reappearance of CHBA. Treatment with okadaic acid, a serine/threonine phosphatase inhibitor, delays the recovery kinetics of Rat-1 cells but not that of thermal-resistant M21 cells. These results are interpreted in terms of a role for hsp70 in the recovery of heat-shocked mammalian cells. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7892235

  19. Bacterial Heat Shock Protein Activity

    PubMed Central

    Maleki, Farajollah; Khosravi, Afra; Nasser, Ahmad; Taghinejad, Hamid

    2016-01-01

    Bacteria are exposed to different types of stress in their growth conditions. They have developed appropriate responses, modulated by the re-modeling of protein complexes and by phosphorylation dependent signal transduction systems, to adapt and to survive in a variety range of nature. Proteins are essential components for biologic activity in the eukaryotic and prokaryotic cell. Heat Shock Proteins (HSP) have been identified from various organisms and have critical role in cell hemostasis. Chaperone can sense environment and have different potential role in the organism evolution. PMID:27134861

  20. Shock interference heating in scramjet engines

    NASA Technical Reports Server (NTRS)

    Wieting, Allan R.

    1990-01-01

    Experimental and analytical research sponsored by the NASA Langley Research center and the NASP Structures Technology Maturation Program to define critical aerothermal loads for the NASP engine is summarized. Presented is a review of (1) shock-shock interaction on the engine cowl leading edge that results in a supersonic jet impinging on the leading edge surface and causes the heat transfer rate to be amplified by a factor of 30 or more over the undisturbed (no shock interaction) flow stagnation point heat transfer rate, (2) the effectiveness of supersonic film cooling with and without the effects of an impinging oblique shock wave, and (3) oblique shock impingement in an axial compression corner.

  1. Heat-shock Proteins and Photodynamic Therapy

    NASA Astrophysics Data System (ADS)

    Baylis, Joanne; Downs, Craig A.; Jones, Linda R.; Heckathorn, Scott A.

    1998-11-01

    Many cancer treatments, such as photodynamic therapy, generate active oxygen species, often in the mitochondria. These oxygen species adversely react with cellular processes, thereby destroying cancer cells and tissue. Heat-shock proteins are up-regulated in response to heat stress or other environmental stresses and are known to protect cells from active oxygen species. In tumor cells, heat-shock proteins accumulate in the mitochondria under non-stress conditions at higher levels than in normal cells. The objective of our work is to determine whether specific mitochondrial heat-shock proteins are responsible for the increased resistance of cancer cells to oxidative-based anti-cancer therapies. We will first determine which heat-shock proteins accumulate in the mitochondria of cancer cells (lung carcinomas). We will determine if the over-expression of specific heat-shock proteins in the mitochondria can protect cells from Photofrin®-mediated photodynamic therapy through protection of mitochondrial electron transport.

  2. [Small heat shock proteins and adaptation to hypertermia in various Drosophila species].

    PubMed

    Shilova, V Iu; Garbuz, D G; Evgen'ev, M B; Zatsepina, O G

    2006-01-01

    Expression level and kinetics of accumulation of small heat shock proteins (21-27 kDa group) have been investigated in three Drosophila species differing significantly by temperature niche and thermosensitivity. It was shown that low-latitude thermotolerant species D. virilis exceeds the high-latitude thermosensitive closely-related species D. lummei as well as distant thermosensitive species D. melanogaster in terms of small heat shock proteins expression and accumulation after temperature elevation. The data obtained enable to postulate an important role of small heat shock proteins in organism basal thermotolerance and general adaptation to adverse conditions of environment. PMID:16637267

  3. Ultrafast collisional ion heating by electrostatic shocks.

    PubMed

    Turrell, A E; Sherlock, M; Rose, S J

    2015-01-01

    High-intensity lasers can be used to generate shockwaves, which have found applications in nuclear fusion, proton imaging, cancer therapies and materials science. Collisionless electrostatic shocks are one type of shockwave widely studied for applications involving ion acceleration. Here we show a novel mechanism for collisionless electrostatic shocks to heat small amounts of solid density matter to temperatures of ∼keV in tens of femtoseconds. Unusually, electrons play no direct role in the heating and it is the ions that determine the heating rate. Ions are heated due to an interplay between the electric field of the shock, the local density increase during the passage of the shock and collisions between different species of ion. In simulations, these factors combine to produce rapid, localized heating of the lighter ion species. Although the heated volume is modest, this would be one of the fastest heating mechanisms discovered if demonstrated in the laboratory. PMID:26563440

  4. Ultrafast collisional ion heating by electrostatic shocks

    PubMed Central

    Turrell, A. E.; Sherlock, M.; Rose, S. J.

    2015-01-01

    High-intensity lasers can be used to generate shockwaves, which have found applications in nuclear fusion, proton imaging, cancer therapies and materials science. Collisionless electrostatic shocks are one type of shockwave widely studied for applications involving ion acceleration. Here we show a novel mechanism for collisionless electrostatic shocks to heat small amounts of solid density matter to temperatures of ∼keV in tens of femtoseconds. Unusually, electrons play no direct role in the heating and it is the ions that determine the heating rate. Ions are heated due to an interplay between the electric field of the shock, the local density increase during the passage of the shock and collisions between different species of ion. In simulations, these factors combine to produce rapid, localized heating of the lighter ion species. Although the heated volume is modest, this would be one of the fastest heating mechanisms discovered if demonstrated in the laboratory. PMID:26563440

  5. Ultrafast collisional ion heating by electrostatic shocks

    NASA Astrophysics Data System (ADS)

    Turrell, A. E.; Sherlock, M.; Rose, S. J.

    2015-11-01

    High-intensity lasers can be used to generate shockwaves, which have found applications in nuclear fusion, proton imaging, cancer therapies and materials science. Collisionless electrostatic shocks are one type of shockwave widely studied for applications involving ion acceleration. Here we show a novel mechanism for collisionless electrostatic shocks to heat small amounts of solid density matter to temperatures of ~keV in tens of femtoseconds. Unusually, electrons play no direct role in the heating and it is the ions that determine the heating rate. Ions are heated due to an interplay between the electric field of the shock, the local density increase during the passage of the shock and collisions between different species of ion. In simulations, these factors combine to produce rapid, localized heating of the lighter ion species. Although the heated volume is modest, this would be one of the fastest heating mechanisms discovered if demonstrated in the laboratory.

  6. Heat Shock Memory in Preimplantation Mouse Embryos

    PubMed Central

    Jia, Yanwei; Hartshorn, Cristina; Hartung, Odelya; Wangh, Lawrence J.

    2010-01-01

    To investigate the consequences of possible physiological stress to embryos caused by the in vitro fertilization procedures, we used as a model heat shock response in preimplantation mouse embryos. A heat shock “memory” was discovered that renders cleavage-stage embryos more responsive at the transcriptional level to secondary perturbation with very low doses of heat, even several cell cycles after the initial stress has occurred. PMID:20378108

  7. Heat shock proteins of higher plants

    PubMed Central

    Key, Joe L.; Lin, C. Y.; Chen, Y. M.

    1981-01-01

    The pattern of protein synthesis changes rapidly and dramatically when the growth temperature of soybean seedling tissue is increased from 28°C (normal) to about 40°C (heat shock). The synthesis of normal proteins is greatly decreased and a new set of proteins, “heat shock proteins,” is induced. The heat shock proteins of soybean consist of 10 new bands on one-dimensional NaDodSO4 gels; a more complex pattern is observed on two-dimensional gels. When the tissue is returned to 28°C after 4 hr at 40°C, there is progressive decline in the synthesis of heat shock proteins and reappearance of a normal pattern of synthesis by 3 or 4 hr. In vitro translation of poly(A)+RNAs isolated from tissues grown at 28 and 40°C shows that the heat shock proteins are translated from a new set of mRNAs induced at 40°C; furthermore, the abundant class mRNAs for many of the normal proteins persist even though they are translated weakly (or not at all) in vivo at 40 or 42.5°C. The heat shock response in soybean appears similar to the much-studied heat shock phenomenon in Drosophila. Images PMID:16593032

  8. Fever, hyperthermia and the heat shock response.

    PubMed

    Singh, Ishwar S; Hasday, Jeffrey D

    2013-08-01

    The heat shock response is a highly conserved primitive response that is essential for survival against a wide range of stresses, including extremes of temperature. Fever is a more recently evolved response, during which organisms raise their core body temperature and temporarily subject themselves to thermal stress in the face of infections. The present review documents studies showing the potential overlap between the febrile response and the heat shock response and how both activate the same common transcriptional programme (although with different magnitudes) including the stress-activated transcription factor, heat shock factor-1, to modify host defences in the context of infection, inflammation and injury. The review focuses primarily on how hyperthermia within the febrile range that often accompanies infections and inflammation acts as a biological response modifier and modifies innate immune responses. The characteristic 2-3 °C increase in core body temperature during fever activates and utilises elements of the heat shock response pathway to modify cytokine and chemokine gene expression, cellular signalling and immune cell mobilisation to sites of inflammation, infection and injury. Interestingly, typical proinflammatory agonists such as Toll-like receptor agonists modify the heat shock-induced transcriptional programme and expression of HSP genes following co-exposure to febrile range hyperthermia or heat shock, suggesting a complex reciprocal regulation between the inflammatory pathway and the heat shock response pathway. PMID:23863046

  9. Heat shock response and groEL sequence of Bartonella henselae and Bartonella quintana.

    PubMed

    Haake, D A; Summers, T A; McCoy, A M; Schwartzman, W

    1997-08-01

    Transmission of Bartonella species from ectoparasites to the mammalian host involves adaptation to thermal and other forms of stress. In order to better understand this process, the heat shock response of Bartonella henselae and Bartonella quintana was studied. Cellular proteins synthesized after shift to higher temperatures were intrinsically labelled with [25S]methionine and analysed by gel electrophoresis and fluorography. The apparent molecular masses of three of the major heat shock proteins produced by the two Bartonella species were virtually identical, migrating at 70, 60 and 10 kDa. A fourth major heat shock protein was larger in B. quintana (20 kDa) than in B. henselae (17 kDa). The maximum heat shock response in B. quintana and B. henselae was observed at 39 degrees C and 42 degrees C, respectively. The groEL genes of both Bartonella species were amplified, sequenced and compared to other known groEL genes. The phylogenetic tree based on the groEL alignment places B. quintana and B. henselae in a monophyletic group with Bartonella bacilliformis. The deduced amino acid sequences of Bartonella GroEL homologues contain signature sequences that are uniquely shared by members of the Gram-negative alpha-purple subdivision of bacteria, which live within eukaryotic cells. Recombinant His6-GroEL fusion proteins were expressed in Escherichia coli to generate specific rabbit antisera. The GroEL antisera were used to confirm the identity of the 60 kDa Bartonella heat shock protein. These studies provide a foundation for evaluating the role of the heat shock response in the pathogenesis of Bartonella infection. PMID:9274034

  10. Association between the 65-kilodalton heat shock protein, Streptococcus sanguis, and the corresponding antibodies in Behçet's syndrome.

    PubMed Central

    Lehner, T; Lavery, E; Smith, R; van der Zee, R; Mizushima, Y; Shinnick, T

    1991-01-01

    The etiology of Behcet's syndrome (BS) is unknown, but a number of streptococcal species have been implicated. A hypothesis was postulated that a shared antigen, such as a stress protein, might account for some of these findings. Indeed, a rabbit antiserum against a 65-kDa heat shock protein of Mycobacterium tuberculosis revealed a corresponding 65-kDa band with all six Streptococcus sanguis strains examined and S. pyogenes but not with S. salivarius. By applying a panel of nine monoclonal antibodies to the mycobacterial 65-kDa heat shock protein, an approximately 65-kDa antigen was identified in the uncommon serotypes of S. sanguis ST3 and H.83 and one with a different Mr was identified in KTH-1 and S. pyogenes. Monoclonal antibodies Y1.2, C1.1, II H9, and ML30, which reacted with these streptococci, recognize residues 11 to 27, 88 to 123, 107 to 122, and 276 to 297 of the 65-kDa heat shock protein, respectively, suggesting that these residues are conserved among some uncommon serotypes of S. sanguis and S. pyogenes. Immunoblot analyses of sera from patients with BS for immunoglobulin A (IgA) and IgG antibodies revealed bands of 65 to 70 kDa with the mycobacterial heat shock protein, S. sanguis strains, and S. pyogenes, although these reactivities were also found to a lesser extent in controls. A 65- to 70-kDa band was found more frequently with S. sanguis KTH-2 or KTH-3 and IgA in serum from patients with BS than with serum from controls (P less than 0.02). Antibodies in serum were then studied by a radioimmunoassay, and in patients with BS this revealed significantly raised IgA antibodies to the recombinant 65-kDa mycobacterial heat shock protein and to soluble protein extracts of S. sanguis ST3, KTH-1, KTH-2, and KTH-3. Whereas significant anti-65-kDa heat shock protein and anti-S. sanguis ST3 antibodies were also found in sera from patients with rheumatoid arthritis and recurrent oral ulcers, the anti-S. sanguis KTH-1, KTH-2, and KTH-3 antibodies were confined

  11. Heat shock response of murine Chlamydia trachomatis.

    PubMed Central

    Engel, J N; Pollack, J; Perara, E; Ganem, D

    1990-01-01

    We have investigated the heat shock response in the mouse pneumonitis strain of Chlamydia trachomatis. The kinetics of the chlamydial heat shock response resembled that of other procaryotes: the induction was rapid, occurring over a 5- to 10-min time period, and was regulated at the level of transcription. Immunoblot analysis and immunoprecipitations with heterologous antisera to the heat shock proteins DnaK and GroEL demonstrated that the rate of synthesis, but not the absolute amount of these two proteins, increased after heat shock. Using a general screen for genes whose mRNAs are induced by heat shock, we identified and cloned two of these. DNA sequence analysis demonstrated that one of the genes is a homolog of dnaK. Further sequence analysis of the region upstream of the dnaK gene revealed that the chlamydial homolog of the grpE gene is located just adjacent to the dnaK gene. The second locus encoded three potential nonoverlapping open reading frames. One of the open reading frames was 52% homologous to the ribosomal protein S18 of Escherichia coli and thus presumably encodes the chlamydial homolog. Interestingly, this ribosomal protein is not known to be induced by heat shock in E. coli. S1 nuclease and primer extension analyses located the start site of the dnaK transcript to the last nucleotide of the grpE coding sequence, suggesting that these two genes, although tandemly arranged, are transcribed separately. No promoter sequences resembling the E. coli consensus heat shock promoter could be identified upstream of either the C. trachomatis dnaK, grpE, or S18 gene. The induction of the dnaK and S18 mRNAs by heat shock occurred at a transcriptional level; their induction could be blocked by rifampin. The mechanisms of induction for these two loci were not the same, however; they were differentially sensitive to chloramphenicol. Whereas the induction of dnaK mRNA required de novo protein synthesis, the induction of the S18 mRNA did not. Thus, C. trachomatis

  12. Heat shock- and alkaline pH-induced proteins of Campylobacter jejuni: characterization and immunological properties.

    PubMed Central

    Wu, Y L; Lee, L H; Rollins, D M; Ching, W M

    1994-01-01

    The protein response to physiological stress was characterized in Campylobacter jejuni 81176 after exposure to heat and pH shock and following periods of recovery. Immunoreactivities of major stress-related proteins were determined with anti-Campylobacter immune rabbit serum and intestinal lavage fluid. Distinct proteins with molecular masses ranging from 10 to 120 kDa were induced and/or released by selective heat or pH treatments. The most notable responses were those of two proteins with apparent molecular masses of 45 and 64 kDa that were induced and two other proteins of 10 and 12 kDa that were released by selective heat shock, alkaline pH treatment, or both. On the basis of N-terminal sequence analysis and immunological cross-reactivity data, the 64- and 10-kDa proteins were the C. jejuni homologs of Escherichia coli GroEL and GroES proteins, respectively. Enhanced chemiluminescence Western blotting (immunoblotting) revealed that all four proteins were among the major protein antigens recognized by anti-Campylobacter rabbit serum immunoglobulin G (IgG) and immune rabbit intestinal lavage IgA (secretory IgA). The results of this investigation suggest that the C. jejuni 10-, 12-, 45-, and 64-kDa proteins and a number of minor stress-related proteins deserve further evaluation of their respective roles in Campylobacter pathogenesis and immunity. Images PMID:7927682

  13. Chromospheric heating by acoustic shock waves

    NASA Technical Reports Server (NTRS)

    Jordan, Stuart D.

    1993-01-01

    Work by Anderson & Athay (1989) suggests that the mechanical energy required to heat the quiet solar chromosphere might be due to the dissipation of weak acoustic shocks. The calculations reported here demonstrate that a simple picture of chromospheric shock heating by acoustic waves propagating upward through a model solar atmosphere, free of both magnetic fields and local inhomogeneities, cannot reproduce their chromospheric model. The primary reason is the tendency for vertically propagating acoustic waves in the range of allowed periods to dissipate too low in the atmosphere, providing insufficient residual energy for the middle chromosphere. The effect of diverging magnetic fields and the corresponding expanding acoustic wavefronts on the mechanical dissipation length is then discussed as a means of preserving a quasi-acoustic heating hypothesis. It is argued that this effect, in a canopy that overlies the low chromosphere, might preserve the acoustic shock hypothesis consistent with the chromospheric radiation losses computed by Anderson & Athay.

  14. Heat shock proteins in multiple myeloma

    PubMed Central

    Zhang, Lei; Fok, Jacqueline H.L.; Davies, Faith E.

    2014-01-01

    Heat shock proteins are molecular chaperones with a central role in protein folding and cellular protein homeostasis. They also play major roles in the development of cancer and in recent years have emerged as promising therapeutic targets. In this review, we discuss the known molecular mechanisms of various heat shock protein families and their involvement in cancer and in particular, multiple myeloma. In addition, we address the current progress and challenges in pharmacologically targeting these proteins as anti-cancer therapeutic strategies PMID:24675290

  15. Allergenic Characterization of 27-kDa Glycoprotein, a Novel Heat Stable Allergen, from the Pupa of Silkworm, Bombyx mori

    PubMed Central

    Son, Mina; Lee, June Yong

    2016-01-01

    Boiled silkworm pupa is a traditional food in Asia, and patients with silkworm pupa food allergy are common in these regions. Still now only one allergen from silkworm, arginine kinase, has been identified. The purpose of this study was to identify novel food allergens in silkworm pupa by analyzing a protein extract after heat treatment. Heat treated extracts were examined by proteomic analysis. A 27-kDa glycoprotein was identified, expressed in Escherichia coli, and purified. IgE reactivity of the recombinant protein was investigated by ELISA. High molecular weight proteins (above 100 kDa) elicited increased IgE binding after heat treatment compared to that before heat treatment. The molecular identities of these proteins, however, could not be determined. IgE reactivity toward a 27-kDa glycoprotein was also increased after heating the protein extract. The recombinant protein was recognized by IgE antibodies from allergic subjects (33.3%). Glycation or aggregation of protein by heating may create new IgE binding epitopes. Heat stable allergens are shown to be important in silkworm allergy. Sensitization to the 27-kDa glycoprotein from silkworm may contribute to elevation of IgE to silkworm. PMID:26770033

  16. Allergenic Characterization of 27-kDa Glycoprotein, a Novel Heat Stable Allergen, from the Pupa of Silkworm, Bombyx mori.

    PubMed

    Jeong, Kyoung Yong; Son, Mina; Lee, June Yong; Park, Kyung Hee; Lee, Jae-Hyun; Park, Jung-Won

    2016-01-01

    Boiled silkworm pupa is a traditional food in Asia, and patients with silkworm pupa food allergy are common in these regions. Still now only one allergen from silkworm, arginine kinase, has been identified. The purpose of this study was to identify novel food allergens in silkworm pupa by analyzing a protein extract after heat treatment. Heat treated extracts were examined by proteomic analysis. A 27-kDa glycoprotein was identified, expressed in Escherichia coli, and purified. IgE reactivity of the recombinant protein was investigated by ELISA. High molecular weight proteins (above 100 kDa) elicited increased IgE binding after heat treatment compared to that before heat treatment. The molecular identities of these proteins, however, could not be determined. IgE reactivity toward a 27-kDa glycoprotein was also increased after heating the protein extract. The recombinant protein was recognized by IgE antibodies from allergic subjects (33.3%). Glycation or aggregation of protein by heating may create new IgE binding epitopes. Heat stable allergens are shown to be important in silkworm allergy. Sensitization to the 27-kDa glycoprotein from silkworm may contribute to elevation of IgE to silkworm. PMID:26770033

  17. Heat shock triggers rapid protein phosphorylation in soybean seedings

    SciTech Connect

    Krishnan, H.B.; Pueppke, S.G.

    1987-10-29

    Heat shock arrests the synthesis of many cellular proteins and simultaneously initiates expression of a unique set of proteins, termed heat shock proteins. We have found that heat shock rapidly triggers phosphorylation of a set of proteins in soybean seedlings. Although the kinetics of phosphorylation and the heat shock response are similar, the major identified phosphorylation products do not comigrate with heat shock proteins on polyacrylamide gels. Cadmium, which is known to induce the heat shock response, stimulates phosphorylation of the same set of proteins. The rapidity of phosphorylation suggests that it may play a pivotal role in sensing and transducing elevated temperature stress in plants.

  18. Ancient heat shock gene is dispensable.

    PubMed Central

    Bardwell, J C; Craig, E A

    1988-01-01

    Hsp83 is a major eucaryotic heat shock protein and one of the most conserved proteins known. We have isolated an Escherichia coli gene homologous to eucaryotic Hsp83 and used it to construct a deletion mutation. The E. coli mutant was viable but had a slight growth disadvantage that increased with temperature. Images PMID:3290192

  19. Heat Shock Proteins in Association with Heat Tolerance in Grasses

    PubMed Central

    Xu, Yan; Zhan, Chenyang; Huang, Bingru

    2011-01-01

    The grass family Poaceae includes annual species cultivated as major grain crops and perennial species cultivated as forage or turf grasses. Heat stress is a primary factor limiting growth and productivity of cool-season grass species and is becoming a more significant problem in the context of global warming. Plants have developed various mechanisms in heat-stress adaptation, including changes in protein metabolism such as the induction of heat shock proteins (HSPs). This paper summarizes the structure and function of major HSPs, recent research progress on the association of HSPs with grass tolerance to heat stress, and incorporation of HSPs in heat-tolerant grass breeding. PMID:22084689

  20. Infrared Images of Shock-Heated Tin

    SciTech Connect

    Craig W. McCluskey; Mark D. Wilke; William D. Turley; Gerald D. Stevens; Lynn R. Veeser; Michael Grover

    2004-09-01

    High-resolution, gated infrared images were taken of tin samples shock heated to just below the 505 K melting point. Sample surfaces were either polished or diamond-turned, with grain sizes ranging from about 0.05 to 10 mm. A high explosive in contact with a 2-mm-thick tin sample induced a peak sample stress of 18 GPa. Interferometer data from similarly-driven tin shots indicate that immediately after shock breakout the samples spall near the free (imaged) surface with a scab thickness of about 0.1 mm.

  1. Localization of small heat shock proteins to the higher plant endomembrane system. [Low-molecular-weight heat shock proteins

    SciTech Connect

    Helm, K.W.; Vierling, E. ); LaFayette, P.R.; Nagao, R.T.; Key, J.L. )

    1993-01-01

    Most eukaryotic cells respond to high temperature and other stresses with the production of heat shock proteins, which aid in cell survival. There are four major classes of heat shock proteins HSP90, HSP70, HSP60 and low-molecular weight HSP. The data from this research indicate that members of the low-molecular weight heat shock proteins are most likely resident endoplasmic reticulum (ER) proteins and may be similar in function to related low-molecular weight heat shock proteins in the cytoplasm. The low-molecular weight heat shock proteins, the HSP90 and the HSP70 all appear to localize to the endoplasmic reticulum. Since the ER-localized low-molecular weight heat shock proteins are physically separated from their counterparts in other cell compartments, investigations of the ER-localized heat shock proteins provides a simplified model system for determining the functions of low-molecular weight heat shock proteins in eukaryotes.

  2. Constitutive heat shock protein 70 (HSC70) expression in rainbow trout hepatocytes: effect of heat shock and heavy metal exposure.

    PubMed

    Boone, Adrienne N; Vijayan, Mathilakath M

    2002-06-01

    The 70-kDa family of heat shock proteins plays an important role as molecular chaperones in unstressed and stressed cells. The constitutive member of the 70 family (hsc70) is crucial for the chaperoning function of unstressed cells, whereas the inducible form (hsp70) is important for allowing cells to cope with acute stressor insult, especially those affecting the protein machinery. In fish, the role of hsc70 in the cellular stress response process is less clear primarily because of the lack of a fish-specific antibody for hsc70 detection. In this study, we purified hsc70 to homogeneity from trout liver using a three-step purification protocol with differential centrifugation, ATP-agarose affinity chromatography and electroelution. Polyclonal antibodies to trout hsc70 generated in rabbits cross-reacted strongly with both purified trout hsc70 protein and also purified recombinant bovine hsc70. Two-dimensional electrophoresis followed by Western blotting confirmed that the isoelectric point of rainbow trout hsc70 was more acidic than hsp70. Using this antibody, we detected hsc70 content in the liver, heart, gill and skeletal muscle of unstressed rainbow trout. Primary cultures of trout hepatocytes subjected to a heat shock (+15 degrees C for 1 h) or exposed to either CuSO(4) (200 microM for 24 h), CdCl(2) (10 microM for 24 h) or NaAsO(2) (50 microM for 1 h) resulted in higher hsp70 accumulation over a 24-h period. However, hsc70 content showed no change with either heat shock or heavy metal exposure suggesting that hsc70 is not modulated by sublethal acute stressors in trout hepatocytes. Taken together, we have for the first time generated polyclonal antibodies specific to rainbow trout hsc70 and this antibody will allow for the characterization of the role of hsc70 in the cellular stress response process in fish. PMID:12106899

  3. PUTATIVE CREATINE KINASE M-ISOFORM IN HUMAN SPERM IS IDENTIFIED AS THE 70-KILODALTON HEAT SHOCK PROTEIN HSPA2

    EPA Science Inventory

    THE PUTATIVE CREATINE KINASE M-ISOFORM IN HUMAN SPERM
    IS IDENTIFIED AS THE 70 kDa HEAT SHOCK PROTEIN HSPA2

    * Gabor Huszar1, Kathryn Stone2, David Dix3 and Lynne Vigue1
    1The Sperm Physiology Laboratory, Department of Obstetrics and Gynecology, 2 W.M. Keck Foundatio...

  4. A constitutive heat shock element-binding factor is immunologically identical to the Ku autoantigen.

    PubMed

    Kim, D; Ouyang, H; Yang, S H; Nussenzweig, A; Burgman, P; Li, G C

    1995-06-23

    Analysis of the heat shock element (HSE)-binding proteins in extracts of rodent cells, during heat shock and their post-heat shock recovery, indicates that the regulation of heat shock response involves a constitutive HSE-binding factor (CHBF), in addition to the heat-inducible heat shock factor HSF1. We purified the CHBF to apparent homogeneity from HeLa cells using column chromatographic techniques including an HSE oligonucleotide affinity column. The purified CHBF consists of two polypeptides with apparent molecular masses of 70 and 86 kDa. Immunoblot and gel mobility shift analysis verify that CHBF is identical or closely related to the Ku autoantigen. The DNA binding characteristics of CHBF to double-stranded or single-stranded DNA are similar to that of Ku autoantigen. In gel mobility shift analysis using purified CHBF and recombinant human HSF1, CHBF competes with HSF1 for the binding of DNA sequences containing HSEs in vitro. Furthermore, when Rat-1 cells were co-transfected with human Ku expression vectors and the hsp70-promoter-driven luciferase reporter gene, thermal induction of luciferase is significantly suppressed relative to cells transfected with only the hsp70-luciferase construct. These data suggest a role of CHBF (or Ku protein) in the regulation of heat response in vivo. PMID:7797514

  5. The expression of heat shock protein hsp27 and a complexed 22-kilodalton protein is inversely correlated with oncogenicity of adenovirus-transformed cells.

    PubMed Central

    Zantema, A; de Jong, E; Lardenoije, R; van der Eb, A J

    1989-01-01

    We isolated a monoclonal antibody that immunoprecipitated two proteins of 22 and 27 kilodaltons (kDa) from nononcogenic adenovirus type 5 early region 1 (E1)-transformed rat cells but not from oncogenic adenovirus type 12 E1-transformed rat cells. In a variety of adenovirus-transformed cells including cells transformed by E1A and the c-H-ras oncogene, we found a perfect, inverse correlation between the presence of these two proteins and the oncogenicity of these cells in syngeneic immunocompetent rats. Characterization of the two proteins revealed that they occur in a large (700-kDa) complex and that the 27-kDa protein is identical to the already known 27-kDa (28-kDa) heat shock protein hsp27. The suppression of the hsp27 protein in oncogenic cells is further demonstrated by the fact that its mRNA is absent even after heat-shock induction. Images PMID:2746733

  6. Heat-Shock Factor 1 Controls Genome-wide Acetylation in Heat-shocked Cells

    PubMed Central

    Fritah, Sabrina; Col, Edwige; Boyault, Cyril; Govin, Jérôme; Sadoul, Karin; Chiocca, Susanna; Christians, Elisabeth; Khochbin, Saadi; Jolly, Caroline

    2009-01-01

    A major regulatory function has been evidenced here for HSF1, the key transcription factor of the heat-shock response, in a large-scale remodeling of the cell epigenome. Indeed, upon heat shock, HSF1, in addition to its well-known transactivating activities, mediates a genome-wide and massive histone deacetylation. Investigating the underlying mechanisms, we show that HSF1 specifically associates with and uses HDAC1 and HDAC2 to trigger this heat-shock–dependent histone deacetylation. This work therefore identifies HSF1 as a master regulator of global chromatin acetylation and reveals a cross-talk between HSF1 and histone deacetylases in the general control of genome organization in response to heat shock. PMID:19793920

  7. Heat Shock-Independent Induction of Multidrug Resistance by Heat Shock Factor 1†

    PubMed Central

    Tchénio, Thierry; Havard, Marilyne; Martinez, Luis A.; Dautry, François

    2006-01-01

    The screening of two different retroviral cDNA expression libraries to select genes that confer constitutive doxorubicin resistance has in both cases resulted in the isolation of the heat shock factor 1 (HSF1) transcription factor. We show that HSF1 induces a multidrug resistance phenotype that occurs in the absence of heat shock or cellular stress and is mediated at least in part through the constitutive activation of the multidrug resistance gene 1 (MDR-1). This drug resistance phenotype does not correlate with an increased expression of heat shock-responsive genes (heat shock protein genes, or HSPs). In addition, HSF1 mutants lacking HSP gene activation are also capable of conferring multidrug resistance, and only hypophosphorylated HSF1 complexes accumulate in transduced cells. Our results indicate that HSF1 can activate MDR-1 expression in a stress-independent manner that differs from the canonical heat shock-activated mechanism involved in HSP induction. We further provide evidence that the induction of MDR-1 expression occurs at a posttranscriptional level, revealing a novel undocumented role for hypophosphorylated HSF1 in posttranscriptional gene regulation. PMID:16382149

  8. A 31-kDa seminal plasma heparin-binding protein reduces cold shock stress during cryopreservation of cross-bred cattle bull semen.

    PubMed

    Patel, M K; Cheema, R S; Bansal, A K; Gandotra, V K

    2016-10-01

    In the present study, a 31-kDa protein, purified from cattle bull seminal plasma heparin-binding proteins (SP-HBP), was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometry. Raw semen of six cross-bred bulls was treated with 31-kDa HBP before cryopreservation to observe its effect on motility, viability, hypo-osmotic swelling test, acrosome integrity, in vitro capacitation/acrosome reaction, and oxidative stress at pre-freeze and frozen-thawed phases of cryopreservation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of 31-kDa protein eluted and purified from SP-HBP (separated on acrylamide gels) resulted in a single band of 40 kDa. In matrix-assisted laser desorption/ionization-time of flight analysis, 12 peptides were identified with matching significantly (P < 0.05) to interlukin-6 of bovine with a top score of 55. Addition of 25 μg/mL of fluorescein isothiocyanate-conjugated 31-kDa protein to raw semen and incubation at 37 °C for 20 minutes before cryopreservation resulted in its binding mainly to head region. Treatment of semen with 31-kDa HBP resulted in a significant (P < 0.05) average increase of 9.2%, 6.8%, and 11.7% and 5.5%, 6.5%, and 11.0% in motile, viable, hypo-osmotic swelling-responsive spermatozoa in six bulls at pre-freeze and frozen-thawed phases of cryopreservation, respectively. Percentage of spermatozoa with intact acrosomes nonsignificantly enhanced in the semen treated with 31-kDa HBP at both phases of cryopreservation. An average nonsignificant increase of 3.1% in in vitro capacitated and acrosome-reacted spermatozoa was obtained in semen supplemented with 31-kDa HBP. Addition of 31-kDa HBP also nonsignificantly reduced Malonadialdehyde (MDA) level by 10.7 and 19.3 μM/10(9) spermatozoa in prefrozen and frozen-thawed semen, respectively. The results obtained here indicate to conclude that treatment of cross-bred cattle bull semen with 31-kDa HBP protects the spermatozoa

  9. DNA transformation via local heat shock

    NASA Astrophysics Data System (ADS)

    Li, Sha; Meadow Anderson, L.; Yang, Jui-Ming; Lin, Liwei; Yang, Haw

    2007-07-01

    This work describes transformation of foreign DNA into bacterial host cells by local heat shock using a microfluidic system with on-chip, built-in platinum heaters. Plasmid DNA encoding ampicillin resistance and a fluorescent protein can be effectively transformed into the DH5α chemically competent E. coli using this device. Results further demonstrate that only one-thousandth of volume is required to obtain transformation efficiencies as good as or better than conventional practices. As such, this work complements other lab-on-a-chip technologies for potential gene cloning/therapy and protein expression applications.

  10. The Hexameric Structures of Human Heat Shock Protein 90

    PubMed Central

    Lee, Cheng-Chung; Lin, Ta-Wei; Ko, Tzu-Ping; Wang, Andrew H.-J.

    2011-01-01

    Background The human 90-kDa heat shock protein (HSP90) functions as a dimeric molecular chaperone. HSP90 identified on the cell surface has been found to play a crucial role in cancer invasion and metastasis, and has become a validated anti-cancer target for drug development. It has been shown to self-assemble into oligomers upon heat shock or divalent cations treatment, but the functional role of the oligomeric states in the chaperone cycle is not fully understood. Principal Findings Here we report the crystal structure of a truncated HSP90 that contains the middle segment and the carboxy-terminal domain, termed MC-HSP90. The structure reveals an architecture with triangular bipyramid geometry, in which the building block of the hexameric assembly is a dimer. In solution, MC-HSP90 exists in three major oligomer states, namely dimer, tetramer and hexamer, which were elucidated by size exclusion chromatography and analytical ultracentrifugation. The newly discovered HSP90 isoform HSP90N that lacks the N-terminal ATPase domain also exhibited similar oligomerization states as did MC-HSP90. Conclusions While lacking the ATPase domain, both MC-HSP90 and HSP90N can self-assemble into a hexameric structure, spontaneously. The crystal structure of MC-HSP90 reveals that, in addition to the C-terminal dimerization domain, the residue W320 in the M domain plays a critical role in its oligomerization. This study not only demonstrates how the human MC-HSP90 forms a hexamer, but also justifies the similar formation of HSP90N by using 3D modeling analysis. PMID:21647436

  11. Heat shock proteins in the kidney.

    PubMed

    Sreedharan, Rajasree; Van Why, Scott K

    2016-10-01

    Heat shock proteins (Hsps) are essential to cell survival through their function as protein chaperones. The role they play in kidney health and disease is varied. Hsp induction may be either beneficial or detrimental to the kidney, depending on the specific Hsp, type of cell, and context. This review addresses the role of Hsps in the kidney, including during development, as osmoprotectants, and in various kidney disease models. Heat shock transcription factor, activated by a stress on renal cells, induces Hsp elaboration and separately regulates immune responses that can contribute to renal injury. Induced Hsps in the intracellular compartment are mostly beneficial in the kidney by stabilizing and restoring cell architecture and function through acting as protein chaperones. Intracellular Hsps also inhibit apoptosis and facilitate cell proliferation, preserving renal tubule viability after acute injury, but enhancing progression of cystic kidney disease and malignancy. Induced Hsps in the extracellular compartment, either circulating or located on outer cell membranes, are mainly detrimental through enhancing inflammation pathways to injury. Correctly harnessing these stress proteins promises the opportunity to alter the course of acute and chronic kidney disease. PMID:26913726

  12. Intracellular trafficking of heat shock factor 2.

    PubMed

    Le Goff, Pascale; Le Dréan, Yves; Le Péron, Christine; Le Jossic-Corcos, Catherine; Ainouche, Abdelkadder; Michel, Denis

    2004-04-01

    HSF2 is an enigmatic member of the heat shock factor family, identified in the homeotherm classes of birds and mammals. We report the characterization of HSF2 from an evolutionary ancient vertebrate, the fish rainbow trout (rtHSF2). rtHSF2 appears closely related to its mammalian counterparts at structural and functional levels. The conservation of the distinctive features of HSF2 from fish to human suggests that it should ensure important biological functions, not redundant with those of HSF1. Proteasome inhibition, reported as a potent stimulator of HSF2, leads to the stabilization and to a striking nuclear trafficking of rtHSF2-GFP fusion protein. Upon treatment with the proteasome inhibitor MG132, rtHSF2-GFP accumulates into PML nuclear bodies (NBs) independently of its sumoylation and, if expressed at moderate level, moves to nucleoli. The translocation of rtHSF2-GFP from NBs to nucleoli is greatly favored by overexpression of the heat shock protein Hsp70. The mammalian counterpart mouse HSF2 (mHSF2) also exhibited changes in intracellular distribution upon MG132 treatment. mHSF2 partitioned between a juxtanuclear area that we characterized as an aggresome and the nucleoli. These relocalizations are likely to reflect common structural changes of mouse and trout HSF2 upon activation. PMID:15023536

  13. Heat shock stimulation of a tilapia heat shock protein 70 promoter is mediated by a distal element.

    PubMed Central

    Molina, A; Di Martino, E; Martial, J A; Muller, M

    2001-01-01

    We reported previously that a tilapia (Oreochromis mossambicus) heat shock protein 70 (HSP70) promoter is able to confer heat shock response on a reporter gene after transient expression both in cell culture and in microinjected zebrafish embryos. Here we present the first functional analysis of a fish HSP70 promoter, the tiHSP70 promoter. Using transient expression experiments in carp EPC (epithelioma papulosum cyprini) cells and in microinjected zebrafish embryos, we show that a distal heat shock response element (HSE1) at approx. -800 is predominantly responsible for the heat shock response of the tiHSP70 promoter. This element specifically binds an inducible transcription factor, most probably heat shock factor, and a constitutive factor. The constitutive complex is not observed with the non-functional, proximal HSE3 sequence, suggesting that both factors are required for the heat shock response mediated by HSE1. PMID:11368761

  14. Hsp56: A novel heat shock protein associated with untransformed steroid receptor complexes

    SciTech Connect

    Sanchez, E.R. )

    1990-12-25

    The recently-described p59 protein has been shown to be associated with untransformed steroid receptors present in rabbit uterus and rat liver cytosols while a smaller version of this protein (p56) interacts with glucocorticoid receptors in human IM-9 cell cytosols. In addition to interacting with glucocorticoid receptors, the p56 protein of IM-9 cell cytosol is also found as part of a large heteromeric complex that contains both the 70-kDa and 90-kDa heat shock proteins (hsp70 and hsp90, respectively). Given this association of p56 with the two major stress proteins, I have speculated that p56 may itself be a heat shock protein. In this paper, the effect of heat stress on the rate of synthesis of p56 is determined. Intact IM-9 cells were exposed to 37 or 43 degrees C for 4 h, followed by pulse-labeling with (35S)methionine. Analysis of whole cytosolic extracts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography reveal an increased rate of radiolabeling for hsp70, hsp90, hsp100, ad hsp110, but no heat-inducible protein of smaller relative molecular mass is detected. However, immune-purification of p56 from normal and heat-stressed cytosols with the EC1 monoclonal antibody results in the presence of a 56-kDa protein that exhibits an increased rate of synthesis in response to heat stress. The results of two-dimensional gel Western blots employing the EC1 antibody demonstrate that this heat-inducible protein is indeed the EC1-reactive p56 protein and that the induction effect is not due to unequal yields of p56 during immune-purification.

  15. Induction of mycobacterial proteins during phagocytosis and heat shock: a time interval analysis.

    PubMed

    Alavi, M R; Affronti, L F

    1994-05-01

    Mycobacterium tuberculosis survives macrophage bactericidal activities by mechanisms that may include induction of stress proteins. We sought to determine whether the synthesis of any mycobacterial proteins is increased during phagocytosis and whether any of these proteins are also up-regulated during heat shock. Protein synthesis by M. tuberculosis H37Ra during phagocytosis by the mouse macrophage cell line IC-21, and during heat shock at 45 and 48 degrees C, was monitored at various time intervals using 35S-labeled methionine/cysteine and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Our data suggest the existence of certain common elements in the stress response of mycobacteria to the three stress stimuli. This apparent similarity was best characterized by the up-regulation of a 25-kDa protein after exposure to each of the stress conditions. Furthermore, this 25-kDa protein and a 37-kDa protein that was also synthesized during phagocytosis appeared to be extracellular because they were preferentially solubilized when infected macrophages were lysed with 0.5% NP-40. PMID:8182341

  16. Modulation of Alloimmunity by Heat Shock Proteins

    PubMed Central

    Borges, Thiago J.; Lang, Benjamin J.; Lopes, Rafael L.; Bonorino, Cristina

    2016-01-01

    The immunological mechanisms that evolved for host defense against pathogens and injury are also responsible for transplant rejection. Host rejection of foreign tissue was originally thought to be mediated mainly by T cell recognition of foreign MHC alleles. Management of solid organ transplant rejection has thus focused mainly on inhibition of T cell function and matching MHC alleles between donor and host. Recently, however, it has been demonstrated that the magnitude of the initial innate immune responses upon transplantation has a decisive impact on rejection. The exact mechanisms underlying this phenomenon have yet to be characterized. Ischemic cell death and inflammation that occur upon transplantation are synonymous with extracellular release of various heat shock proteins (Hsps), many of which have been shown to have immune-modulatory properties. Here, we review the impact of Hsps upon alloimmunity and discuss the potential use of Hsps as accessory agents to improve solid organ transplant outcomes. PMID:27555846

  17. Riboflavin protects mice against liposaccharide-induced shock through expression of heat shock protein 25

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riboflavin (vitamin B2) is a water-soluble vitamin essential for normal cellular functions, growth and development. The study was aimed at investigating the effects of vitamin B2 on the survival rate, and expressions of tissue heat shock protein 25 (HSP25) and heat shock factor 1 (HSF1) in mice und...

  18. Heat shock proteins and heat shock factor 1 in carcinogenesis and tumor development: an update

    PubMed Central

    2013-01-01

    Heat shock proteins (HSP) are a subset of the molecular chaperones, best known for their rapid and abundant induction by stress. HSP genes are activated at the transcriptional level by heat shock transcription factor 1 (HSF1). During the progression of many types of cancer, this heat shock transcriptional regulon becomes co-opted by mechanisms that are currently unclear, although evidently triggered in the emerging tumor cell. Concerted activation of HSF1 and the accumulation of HSPs then participates in many of the traits that permit the malignant phenotype. Thus cancers of many histologies exhibit activated HSF1 and increased HSP levels that may help to deter tumor suppression and evade therapy in the clinic. We review here the extensive work that has been carried out and is still in progress aimed at: (1) understanding the oncogenic mechanisms by which HSP genes are switched on, (2) determining the roles of HSF1 / HSP in malignant transformation and, (3) discovering approaches to therapy based on disrupting the influence of the HSF1 controlled transcriptome in cancer. PMID:22885793

  19. Infrared Emissions from Shock Heated Hydrocarbons

    NASA Technical Reports Server (NTRS)

    Stephens, K. M.; Bauer, S. H.

    1994-01-01

    The primary objective of this study was to ascertain whether low molecular weight hydrocarbons (LMWH) in the range C4 to C7, upon heating to temperatures above 900 K, emit IR radiations at frequencies that correspond to the 'unidentified infrared' (UIR) features - the recorded emissions from a variety of astronomical sources - reflection nebulae, HII regions, planetary nebulae, spiral galaxies and other extra galactic objects. We describe IR emission spectra recorded from shock-heated gases (C2H2; (H3C)2C = CH2; H2C = C(CH3) - C(CH3) = CH2; (H3C)2C = CH - C(CH3) = CH2), that arise from excitation of the fundamental C-H stretching vibrations. While the IR emissions from LMWH, anticipated over the entire spectra range, do not present a perfect match to UIR, the correspondence over several wavelength regions is better than the emissions anticipated from polycyclic aromatic hydrocarbon (PAH) species. Finally, we briefly review the range of proposals that have been presented for the origin of the UIR bands.

  20. Structure of fast shocks in the presence of heat conduction

    SciTech Connect

    Tsai, C. L.; Chen, H. H.; Wu, B. H.; Lee, L. C.

    2007-12-15

    There are three types of magnetohydrodynamic (MHD) shocks: the fast shock, intermediate shock, and slow shock. The structure of slow shocks and intermediate shocks in the presence of heat conduction has been studied earlier [C. L. Tsai, R. H. Tsai, B. H. Wu, and L. C. Lee, Phys. Plasmas 9, 1185 (2002); C. L. Tsai, B. H. Wu, and L. C. Lee, Phys. Plasmas 12, 82501 (2005)]. Based on one-dimensional MHD numerical simulations with a heat conduction term, the evolution and structure of fast shocks are studied. The fast shock will form a foreshock in the presence of heat conduction. The foreshock is formed due to the heat flow from downstream to upstream and located in the immediate upstream of the main shock. In the steady state, the value of diffusion velocity V{sub d} in the foreshock is found to nearly equal the upstream convection velocity in the fast shock frame. It is found that the density jump across the main shock in high Mach number case can be much larger than 4 in the early simulation time. However the density jump will gradually evolve to a value smaller than 4 at steady state. By using the modified Rankine-Hugoniot relations with heat flux, the density jump across the fast shock is examined for various upstream parameters. The results show that the calculated density jump with heat flux is very close to the simulation value and the density jump can far exceed the maximum value of 4 without heat conduction. The structure of foreshock and main shock is also studied under different plasma parameters, such as the heat conductivity K{sub 0}, the ratio of upstream plasma pressure to magnetic pressure {beta}{sub 1}, Alfven Mach number M{sub A1}, and the angle {theta}{sub 1} between shock normal and magnetic field. It is found that as the upstream shock parameters K{sub 0}, {beta}{sub 1}, and M{sub A1} increase or {theta}{sub 1} decreases, the width of foreshock L{sub d} increases. The present results can be applied to fast shocks in the solar corona, solar wind

  1. The Mycobacterium tuberculosis 65-kilodalton antigen is a heat shock protein which corresponds to common antigen and to the Escherichia coli GroEL protein.

    PubMed Central

    Shinnick, T M; Vodkin, M H; Williams, J C

    1988-01-01

    Monoclonal hybridoma antibodies directed against a 65-kilodalton (kDa) mycobacterial protein could detect similarly sized antigens in many other bacterial species. In Pseudomonas aeruginosa, the cross-reacting protein corresponded to a 62-kDa antigen that has been called Common Antigen. The mycobacterial 65-kDa antigen and Common Antigen are similar in that both (i) are highly immunoreactive molecules, (ii) contain species-specific and genus-specific epitopes in addition to the broadly cross-reactive epitopes, (iii) can be isolated as homomultimers of greater than 240 kDa, and (iv) have similar amino acid compositions. In Escherichia coli, the cross-reactive protein corresponded to the GroEL protein. Both the GroEL protein and the mycobacterial 65-kDa protein are expressed as heat shock proteins. Images PMID:2892795

  2. Multi-Level Interactions Between Heat Shock Factors, Heat Shock Proteins, and the Redox System Regulate Acclimation to Heat.

    PubMed

    Driedonks, Nicky; Xu, Jiemeng; Peters, Janny L; Park, Sunghun; Rieu, Ivo

    2015-01-01

    High temperature has become a global concern because it seriously affects the growth and reproduction of plants. Exposure of plant cells to high temperatures result in cellular damage and can even lead to cell death. Part of the damage can be ascribed to the action of reactive oxygen species (ROS), which accumulate during abiotic stresses such as heat stress. ROS are toxic and can modify other biomacromolecules including membrane lipids, DNA, and proteins. In order to protect the cells, ROS scavenging is essential. In contrast with their inherent harms, ROS also function as signaling molecules, inducing stress tolerance mechanisms. This review examines the evidence for crosstalk between the classical heat stress response, which consists of heat shock factors (HSFs) and heat shock proteins (HSPs), with the ROS network at multiple levels in the heat response process. Heat stimulates HSF activity directly, but also indirectly via ROS. HSFs in turn stimulate the expression of HSP chaperones and also affect ROS scavenger gene expression. In the short term, HSFs repress expression of superoxide dismutase scavenger genes via induction of miRNA398, while they also activate scavenger gene expression and stabilize scavenger protein activity via HSP induction. We propose that these contrasting effects allow for the boosting of the heat stress response at the very onset of the stress, while preventing subsequent oxidative damage. The described model on HSFs, HSPs, ROS, and ROS scavenger interactions seems applicable to responses to stresses other than heat and may explain the phenomenon of crossacclimation. PMID:26635827

  3. Automated Scalable Heat Shock Modification for Standard Aquatic Housing Systems.

    PubMed

    Saera-Vila, Alfonso; Kish, Phillip E; Kahana, Alon

    2015-08-01

    Heat shock is a common technique for inducible gene expression system in a variety of organisms. Heat shock treatment of adult zebrafish is more involved and generally consists of manually transferring fish between housing rack tanks and preheated water tanks or the use of timed heaters in stand-alone aquaria. To avoid excessive fish handling and to take advantage of the continuous flow of a standard housing rack, proposed modifications consisted of installing an aquarium heater inside each tank, manually setting the heater to reach heat shocking temperatures (> 37°C) and, after that, testing that every tank responded equally. To address the limitations in the existing systems, we developed a novel modification of standard zebrafish housing racks to perform heat shock treatment in conditions of continuous water flow. By adding an extra manifold to the housing rack and connecting it to a recirculating bath to create a parallel water flow system, we can increase the temperature from standard conditions (28.5°C) to heat shock conditions with high precision (38.0-38.3°C, mean ± SD = 38.1°C ± 0.14°C) and minimal variation among experimental tanks (coefficient of variation [CV] = 0.04%). This means that there is virtually no need for laborious pretreatment calibrations or continuous adjustments to minimize intertank variation. To test the effectiveness of our design, we utilized this system to induce enhanced green fluorescent protein (EGFP) expression in hsp70-EGFP fish and performed a fin regeneration experiment with hsp70l:dnfgfr1-EGFP fish to confirm that heat-induced gene expression reached physiological levels. In summary, our newly described aquatic heat shock system minimizes effort during heat shock experiments, while ensuring the best water quality and fish welfare and facilitating large heat shock settings or the use of multiple transgenic lines for both research and teaching experiments. PMID:25942613

  4. Automated Scalable Heat Shock Modification for Standard Aquatic Housing Systems

    PubMed Central

    Saera-Vila, Alfonso; Kish, Phillip E.

    2015-01-01

    Abstract Heat shock is a common technique for inducible gene expression system in a variety of organisms. Heat shock treatment of adult zebrafish is more involved and generally consists of manually transferring fish between housing rack tanks and preheated water tanks or the use of timed heaters in stand-alone aquaria. To avoid excessive fish handling and to take advantage of the continuous flow of a standard housing rack, proposed modifications consisted of installing an aquarium heater inside each tank, manually setting the heater to reach heat shocking temperatures (>37°C) and, after that, testing that every tank responded equally. To address the limitations in the existing systems, we developed a novel modification of standard zebrafish housing racks to perform heat shock treatment in conditions of continuous water flow. By adding an extra manifold to the housing rack and connecting it to a recirculating bath to create a parallel water flow system, we can increase the temperature from standard conditions (28.5°C) to heat shock conditions with high precision (38.0–38.3°C, mean±SD=38.1°C±0.14°C) and minimal variation among experimental tanks (coefficient of variation [CV]=0.04%). This means that there is virtually no need for laborious pretreatment calibrations or continuous adjustments to minimize intertank variation. To test the effectiveness of our design, we utilized this system to induce enhanced green fluorescent protein (EGFP) expression in hsp70-EGFP fish and performed a fin regeneration experiment with hsp70l:dnfgfr1-EGFP fish to confirm that heat-induced gene expression reached physiological levels. In summary, our newly described aquatic heat shock system minimizes effort during heat shock experiments, while ensuring the best water quality and fish welfare and facilitating large heat shock settings or the use of multiple transgenic lines for both research and teaching experiments. PMID:25942613

  5. Fever and the heat shock response: distinct, partially overlapping processes

    PubMed Central

    Hasday, Jeffrey D.; Singh, Ishwar S.

    2000-01-01

    The heat shock response is an ancient and highly conserved process that is essential for surviving environmental stresses, including extremes of temperature. Fever is a more recently evolved response, during which organisms temporarily subject themselves to thermal stress in the face of infections. We review studies showing that fever is beneficial in the infected host. We show that core temperatures achieved during fever can activate the heat shock response and discuss some of the biochemical consequences of such an effect. We present data suggesting 4 possible mechanisms by which fever might confer protection: (1) directly killing or inhibiting growth of pathogens; (2) inducing cytoprotective heat shock proteins (Hsps) in host cells; (3) inducing expression of pathogen Hsps, an activator of host defenses; and (4) modifying and orchestrating host defenses. Two of these mechanisms directly involve the heat shock response. We describe how heat shock factor-1, the predominant heat-induced transcriptional enhancer not only activates transcription of Hsps but also regulates expression of pivotal cytokines and early response genes. The relationship between fever and the heat shock response is an illuminating example of how a more recently evolved response might exploit preexisting biochemical pathways for a new function. PMID:11189454

  6. Three light-inducible heat shock genes of Chlamydomonas reinhardtii.

    PubMed Central

    von Gromoff, E D; Treier, U; Beck, C F

    1989-01-01

    Genomic clones representing three Chlamydomonas reinhardtii genes homologous to the Drosophila hsp70 heat shock gene were isolated. The mRNAs of genes hsp68, hsp70, and hsp80 could be translated in vitro into proteins of Mr 68,000, 70,000, and 80,000, respectively. Transcription of these genes increased dramatically upon heat shock, and the corresponding mRNAs rapidly accumulated, reaching a peak at around 30 min after a shift to the elevated temperature. Light also induced the accumulation of the mRNAs encoded by these heat shock genes. A shift of dark-grown cells to light resulted in a drastic increase in mRNA levels, which reached a maximum at around 1 h after the shift. Thus, in Chlamydomonas, expression of hsp70-homologous heat shock genes appears to be regulated by thermal stress and light. Images PMID:2779571

  7. Heat shock response and autophagy—cooperation and control

    PubMed Central

    Dokladny, Karol; Myers, Orrin B; Moseley, Pope L

    2015-01-01

    Protein quality control (proteostasis) depends on constant protein degradation and resynthesis, and is essential for proper homeostasis in systems from single cells to whole organisms. Cells possess several mechanisms and processes to maintain proteostasis. At one end of the spectrum, the heat shock proteins modulate protein folding and repair. At the other end, the proteasome and autophagy as well as other lysosome-dependent systems, function in the degradation of dysfunctional proteins. In this review, we examine how these systems interact to maintain proteostasis. Both the direct cellular data on heat shock control over autophagy and the time course of exercise-associated changes in humans support the model that heat shock response and autophagy are tightly linked. Studying the links between exercise stress and molecular control of proteostasis provides evidence that the heat shock response and autophagy coordinate and undergo sequential activation and downregulation, and that this is essential for proper proteostasis in eukaryotic systems. PMID:25714619

  8. Saccharomyces cerevisiae Genes Involved in Survival of Heat Shock

    PubMed Central

    Jarolim, Stefanie; Ayer, Anita; Pillay, Bethany; Gee, Allison C.; Phrakaysone, Alex; Perrone, Gabriel G.; Breitenbach, Michael; Dawes, Ian W.

    2013-01-01

    The heat-shock response in cells, involving increased transcription of a specific set of genes in response to a sudden increase in temperature, is a highly conserved biological response occurring in all organisms. Despite considerable attention to the processes activated during heat shock, less is known about the role of genes in survival of a sudden temperature increase. Saccharomyces cerevisiae genes involved in the maintenance of heat-shock resistance in exponential and stationary phase were identified by screening the homozygous diploid deletants in nonessential genes and the heterozygous diploid mutants in essential genes for survival after a sudden shift in temperature from 30 to 50°. More than a thousand genes were identified that led to altered sensitivity to heat shock, with little overlap between them and those previously identified to affect thermotolerance. There was also little overlap with genes that are activated or repressed during heat-shock, with only 5% of them regulated by the heat-shock transcription factor. The target of rapamycin and protein kinase A pathways, lipid metabolism, vacuolar H+-ATPase, vacuolar protein sorting, and mitochondrial genome maintenance/translation were critical to maintenance of resistance. Mutants affected in l-tryptophan metabolism were heat-shock resistant in both growth phases; those affected in cytoplasmic ribosome biogenesis and DNA double-strand break repair were resistant in stationary phase, and in mRNA catabolic processes in exponential phase. Mutations affecting mitochondrial genome maintenance were highly represented in sensitive mutants. The cell division transcription factor Swi6p and Hac1p involved in the unfolded protein response also play roles in maintenance of heat-shock resistance. PMID:24142923

  9. Barcoding heat shock proteins to human diseases: looking beyond the heat shock response

    PubMed Central

    Kakkar, Vaishali; Meister-Broekema, Melanie; Minoia, Melania; Carra, Serena; Kampinga, Harm H.

    2014-01-01

    There are numerous human diseases that are associated with protein misfolding and the formation of toxic protein aggregates. Activating the heat shock response (HSR) – and thus generally restoring the disturbed protein homeostasis associated with such diseases – has often been suggested as a therapeutic strategy. However, most data on activating the HSR or its downstream targets in mouse models of diseases associated with aggregate formation have been rather disappointing. The human chaperonome consists of many more heat shock proteins (HSPs) that are not regulated by the HSR, however, and researchers are now focusing on these as potential therapeutic targets. In this Review, we summarize the existing literature on a set of aggregation diseases and propose that each of them can be characterized or ‘barcoded’ by a different set of HSPs that can rescue specific types of aggregation. Some of these ‘non-canonical’ HSPs have demonstrated effectiveness in vivo, in mouse models of protein-aggregation disease. Interestingly, several of these HSPs also cause diseases when mutated – so-called chaperonopathies – which are also discussed in this Review. PMID:24719117

  10. Altered phosphorylation of. tau. protein in heat-shocked rats and patients with Alzheimer disease

    SciTech Connect

    Papasozomenos, S.C.; Yuan Su Baylor College of Medicine, Houston, TX )

    1991-05-15

    Six hours after heat shocking 2- to 3-month-old male and female Sprague-Dawley rats at 42C for 15 min, the authors analyzed {tau} protein immunoreactivity in SDS extracts of cerebrums and peripheral nerves by using immunoblot analysis and immunohistochemistry with the anti-{tau} monoclonal antibody Tau-1, which recognizes a phosphate-dependent nonphosphorylated epitope, and with {sup 125}I-labeled protein A. In the cerebal extracts, the authors found altered phosphorylation of {tau} in heat-shocked females, characterized by a marked reduction in the amount of nonphosphorylated {tau}, a doubling of the ratio of total (phosphorylated plus nonphosphorylated) {tau} to nonphosphorylated {tau}, and the appearance of the slowest moving phosphorylated {tau} polypeptide (68 kDa). Similar, but milder, changes were observed in male rats. Quantitative immunoblot analysis of cortex and the underlying white matter with Tau-1 and {sup 125}I-labeled protein A showed that the amount of phosphorylated {tau} progressively increased in the Alzheimer disease-affected cerebral cortex, while concurrently a proportionally lesser amount of {tau} entered the white matter axons. The similar findings for the rat heat-shock model and Alzheimer disease suggest that life stressors may play a role in the etiopathogenesis of Alzheimer's disease.

  11. Heavy Ion Heating at Shocks in the Heliosphere

    NASA Astrophysics Data System (ADS)

    Korreck, K. E.; Stevens, M. L.; Lepri, S. T.; Kasper, J. C.

    2014-12-01

    Ions heavier than protons can be used as tracers for heating mechamisms in solar wind plasma. Measurments by the ACE and WIND satellites provide information on the relative heating of the heavy ions versus the protons. Greater than mass proportional heating has been seen at coronal mass ejections (CME) shock fronts. Using ACE SWICS heavy ions data from CME associated shocks, heavy ion heating and the non-thermal nature of helium and oxygen distributions at 1AU is examined. The WIND SWE data set is used to examine the helium distributions at the shock fronts observed at the spacecraft. Understanding the heating and source of energetic particles and their evolution through the heliosphere is relevant to predicting space weather events and the evolution of the solar wind.

  12. Ion heating and energy redistribution across supercritical perpendicular shocks: Application to planetary and interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Liu, Y. D.; Richardson, J. D.; Parks, G. K.

    2013-12-01

    We investigate how the ion dissipative process across supercritical perpendicular shocks depends on the shock front micro-structures. At a collisionless plasma shock, the dissipation and micro-structure of the shock font are dominated by wave-particle interactions. Comparison of the ion thermalization at different kinds of shocks, e.g., planetary and interplanetary shocks, can quantify how much interaction is occurring at the shock boundary. Investigation of this problem for diverse solar wind (SW) conditions will yield important information on the dependences of the ion thermalization and energy redistribution on plasma parameters. With the aid of a successful automatic separation method [Yang et al., 2009], the incident ions at the shock can be divided into two parts: reflected (R) ions and directly transmitted (DT) ions. Corresponding heating efficiency of each population of ions at the shock can be calculated respectively. Wilkinson & Schwartz [1990] have theorized that the amount of reflected ions at perpendicular shocks depends on plasma parameters. Based on the Rankine-Hugoniot (R-H) conservation laws, they found that the fraction reflected is strongly dependent on the magnitude of the ratio of specific heat capacities γ chosen in the R-H relations. The main goal of this work is to investigate how the plasma parameters, e.g. the particle velocity distribution, the plasma beta value, seed populations, etc. (from a particle dynamic point of view), control the amount of reflected ions by using one-dimensional (1-D) full-particle-cell simulations. The simulation results may help to explain the ion heating efficiency and energy redistribution at shocks observed by Cluster, Wind, Voyager, etc.

  13. Heat shock increases survival in rats exposed to hyperbaric pressure.

    PubMed

    Medby, Christian; Bye, Anja; Wisløff, Ulrik; Brubakk, Alf O

    2008-12-01

    It has been shown that a single bout of exercise performed 20 hours prior to hyperbaric exposure reduces bubble formation and increases survival in rats. Heat shock proteins (HSPs) are stress proteins expressed in cells that are exposed to different stressors. HSPs are known to protect cells, by binding to proteins and stabilizing them. As it is known that a single bout of exercise induces HSPs, and that HSPs exert their protective effects 20-24 hours after the stimulus for induction, we hypothesized that HSPs might be one mechanism behind the observed exercise-induced protection. We hypothesized that rats that expressed HSPs would develop fewer bubbles and have a lower mortality than their non-stressed control group. Twenty-four female Sprague-Dawley rats (300-330 g) were divided into a heat-shock group and a control group and anaesthetized. The rats in the heat-shock group were heated to 42 ± 0.5 degrees Celsius for 15 min. The following day, all rats were compressed to 700 kPa for 45 min in a hyperbaric chamber. The right ventricles were insonated and bubbles were identified and graded. Six of 12 rats in the heat-shock group survive d, while 1 of 12 control rats survived (Chi square = 5.042, P = 0.034). There was no difference in bubble grade between the groups. The study suggests that the effect of heat shock on survival is not the same as observed after exercise, as the heat-shocked rats developed bubbles. However, heat shock appears to protect rats against the effects of bubbles by an independent mechanism. PMID:22692750

  14. Simple, economical heat-shock devices for zebrafish housing racks.

    PubMed

    Duszynski, Robert J; Topczewski, Jacek; LeClair, Elizabeth E

    2011-12-01

    One reason for the popularity of the zebrafish (Danio rerio) as a model vertebrate is the ability to manipulate gene expression in this organism. A common method is to induce gene expression transiently under control of a heat-shock promoter (e.g., hsp70l). By making simple mechanical adjustments to small aquarium heaters (25-50W), we were able to produce consistent and reliable heat-shock conditions within a conventional zebrafish housing system. Up to two heat-shock intervals per day (>37°C) could be maintained under conditions of continuous flow (5-25 mL/min). Temperature logging every 30 s indicated rapid warm up times, consistent heat-shock lengths, and accurate and precise peak water temperatures (mean±SD=38°C±0.2°C). The biological effects of these heat-shock treatments were confirmed by observing inducible expression of enhanced green fluorescent protein (EGFP) and inhibition of caudal fin regeneration in a transgenic fish line expressing a dominant negative fibroblast growth factor receptor (Tg(hsp70l:dnfgfr1-EGFP)(pd1)). These devices are inexpensive, easily modified, and can be calibrated to accommodate a variety of experimental designs. After setup on a programmable timer, the heaters require no intervention to produce consistent daily heat shocks, and all other standard care protocols can be followed in the fish facility. The simplicity and stability of these devices make them suitable for long-term heat shocks at any stage of the zebrafish lifecycle (>7 days postfertilization), and useful for both laboratory and classroom experiments on transgenic zebrafish. PMID:21913856

  15. Suppression of polyglutamine protein toxicity by co-expression of a heat-shock protein 40 and a heat-shock protein 110.

    PubMed

    Kuo, Y; Ren, S; Lao, U; Edgar, B A; Wang, T

    2013-01-01

    A network of heat-shock proteins mediates cellular protein homeostasis, and has a fundamental role in preventing aggregation-associated neurodegenerative diseases. In a Drosophila model of polyglutamine (polyQ) disease, the HSP40 family protein, DNAJ-1, is a superior suppressor of toxicity caused by the aggregation of polyQ containing proteins. Here, we demonstrate that one specific HSP110 protein, 70 kDa heat-shock cognate protein cb (HSC70cb), interacts physically and genetically with DNAJ-1 in vivo, and that HSC70cb is necessary for DNAJ-1 to suppress polyglutamine-induced cell death in Drosophila. Expression of HSC70cb together with DNAJ-1 significantly enhanced the suppressive effects of DNAJ-1 on polyQ-induced neurodegeneration, whereas expression of HSC70cb alone did not suppress neurodegeneration in Drosophila models of either general polyQ disease or Huntington's disease. Furthermore, expression of a human HSP40, DNAJB1, together with a human HSP110, APG-1, protected cells from polyQ-induced neural degeneration in flies, whereas expression of either component alone had little effect. Our data provide a functional link between HSP40 and HSP110 in suppressing the cytotoxicity of aggregation-prone proteins, and suggest that HSP40 and HSP110 function together in protein homeostasis control. PMID:24091676

  16. Structure of intermediate shocks and slow shocks in a magnetized plasma with heat conduction

    SciTech Connect

    Tsai, C.L.; Wu, B.H.; Lee, L.C.

    2005-08-15

    The structure of slow shocks and intermediate shocks in the presence of a heat conduction parallel to the local magnetic field is simulated from the set of magnetohydrodynamic equations. This study is an extension of an earlier work [C. L. Tsai, R. H. Tsai, B. H. Wu, and L. C. Lee, Phys. Plasmas 9, 1185 (2002)], in which the effects of heat conduction are examined for the case that the tangential magnetic fields on the two side of initial current sheet are exactly antiparallel (B{sub y}=0). For the B{sub y}=0 case, a pair of slow shocks is formed as the result of evolution of the initial current sheet, and each slow shock consists of two parts: the isothermal main shock and the foreshock. In the present paper, cases with B{sub y}{ne}0 are also considered, in which the evolution process leads to the presence of an additional pair of time-dependent intermediate shocks (TDISs). Across the main shock of the slow shock, jumps in plasma density, velocity, and magnetic field are significant, but the temperature is continuous. The plasma density downstream of the main shock decreases with time, while the downstream temperature increases with time, keeping the downstream pressure constant. The foreshock is featured by a smooth temperature variation and is formed due to the heat flow from downstream to upstream region. In contrast to the earlier study, the foreshock is found to reach a steady state with a constant width in the slow shock frame. In cases with B{sub y}{ne}0, the plasma density and pressure increase and the magnetic field decreases across TDIS. The TDIS initially can be embedded in the slow shock's foreshock structure, and then moves out of the foreshock region. With an increasing B{sub y}, the propagation speed of foreshock leading edge tends to decrease and the foreshock reaches its steady state at an earlier time. Both the pressure and temperature downstreams of the main shock decrease with increasing B{sub y}. The results can be applied to the shock heating

  17. Atypical Particle Heating at a Supercritical Interplanetary Shock

    NASA Technical Reports Server (NTRS)

    Wilson, Lynn B., III

    2010-01-01

    We present the first observations at an interplanetary shock of large amplitude (> 100 mV/m pk-pk) solitary waves and large amplitude (approx.30 mV/m pk-pk) waves exhibiting characteristics consistent with electron Bernstein waves. The Bernstein-like waves show enhanced power at integer and half-integer harmonics of the cyclotron frequency with a broadened power spectrum at higher frequencies, consistent with the electron cyclotron drift instability. The Bernstein-like waves are obliquely polarized with respect to the magnetic field but parallel to the shock normal direction. Strong particle heating is observed in both the electrons and ions. The observed heating and waveforms are likely due to instabilities driven by the free energy provided by reflected ions at this supercritical interplanetary shock. These results offer new insights into collisionless shock dissipation and wave-particle interactions in the solar wind.

  18. Heat shock proteins, end effectors of myocardium ischemic preconditioning?

    PubMed Central

    Guisasola, María Concepcion; Desco, Maria del Mar; Gonzalez, Fernanda Silvana; Asensio, Fernando; Dulin, Elena; Suarez, Antonio; Garcia Barreno, Pedro

    2006-01-01

    The purpose of this study was to investigate (1) whether ischemia-reperfusion increased the content of heat shock protein 72 (Hsp72) transcripts and (2) whether myocardial content of Hsp72 is increased by ischemic preconditioning so that they can be considered as end effectors of preconditioning. Twelve male minipigs (8 protocol, 4 sham) were used, with the following ischemic preconditioning protocol: 3 ischemia and reperfusion 5-minute alternative cycles and last reperfusion cycle of 3 hours. Initial and final transmural biopsies (both in healthy and ischemic areas) were taken in all animals. Heat shock protein 72 messenger ribonucleic acid (mRNA) expression was measured by a semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method using complementary DNA normalized against the housekeeping gene cyclophilin. The identification of heat shock protein 72 was performed by immunoblot. In our “classic” preconditioning model, we found no changes in mRNA hsp72 levels or heat shock protein 72 content in the myocardium after 3 hours of reperfusion. Our experimental model is valid and the experimental techniques are appropriate, but the induction of heat shock proteins 72 as end effectors of cardioprotection in ischemic preconditioning does not occur in the first hours after ischemia, but probably at least 24 hours after it, in the so-called “second protection window.” PMID:17009598

  19. Mechanical analysis of a heat-shock induced developmental defect

    NASA Astrophysics Data System (ADS)

    Crews, Sarah M.; McCleery, W. Tyler; Hutson, M. Shane

    2014-03-01

    Embryonic development in Drosophila is a complex process involving coordinated movements of mechanically interacting tissues. Perturbing this system with a transient heat shock can result in a number of developmental defects. In particular, a heat shock applied during the earliest morphogenetic movements of gastrulation can lead to apparent recovery, but then subsequent morphogenetic failure 5-6 hours later during germ band retraction. The process of germ band retraction requires an intact amnioserosa - a single layered extra-embryonic epithelial tissue - and heat shock at gastrulation can induce the later opening of holes in the amnioserosa. These holes are highly correlated with failures of germ band retraction. These holes could be caused by a combination of mechanical weakness in the amnioserosa or local increases in mechanical stress. Here, we assess the role of mechanical stress using confocal imaging to compare cell and tissue morphology in the amnioserosa of normal and heat-shocked embryos and laser hole drilling to map the stress field around the times and locations at which heat-shock induced holes open.

  20. Wavelet transform analysis of chromatin texture changes during heat shock.

    PubMed

    Herbomel, G; Grichine, A; Fertin, A; Delon, A; Vourc'h, C; Souchier, C; Usson, Y

    2016-06-01

    Texture analysis can be a useful tool to investigate the organization of chromatin. Approaches based on multiscale analysis and in particular the 'à trou' wavelet analysis has already been used for microscopy (Olivo Marin). In order to analyse texture changes, the statistical properties of the wavelet coefficient images were summarized by the first four statistical orders: mean, standard deviation, skewness and kurtosis of the coefficient image histogram. The 'à trou' transform provided a representation of the wavelet coefficients and texture parameters with the same statistical robustness throughout the scale spaces. It was applied for quantifying chromatin texture and heat-induced chromatin changes in living cells. We investigated the changes by both laser scanning and spinning disk confocal microscopies and compared the texture parameters before and after increasing duration of heat shock exposure (15 min, 30 min and 1 h). Furthermore, as activation of the heat shock response also correlates with a rapid localization of HSF1 within a few nuclear structures termed nuclear stress bodies (nSBs), we compared the dynamics of nSBs formation with that of textural changes during 1 h of continuous heat shock. Next, we studied the recovery phase following a 1-h heat shock. Significant differences were observed, particularly affecting the perinucleolar region, even for the shortest heat shock time affecting mostly the skewness and standard deviation. Furthermore, progressive changes could be observed according to the duration of heat shock, mostly affecting fine details (pixel-wise changes) as revealed by the parameters, obtained from the first- and second-order wavelet coefficients. 'A trou' wavelet texture analysis provided a sensitive and efficient tool to investigate minute changes of chromatin. PMID:26694695

  1. Chromosome behavior of heat shock induced triploid in Fenneropenaeus chinensis

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaojun; Li, Fuhua; Xiang, Jianhai

    2003-09-01

    Triploidy was induced in Chinese shrimp Fenneropenaeus chinensis by 30±0.5°C heat shock treatment (initiated at 20 min after fertilization) for 10 min to inhibit the release of PB2 at 18.0°C. The highest triploid rate obtained was 84.5% in nauplius stage. The effect of heat shock treatment on meiosis and cleavage of eggs was investigated in this work aimed to establish efficient procedures for triploid induction and to gain understanding of the mechanism of triploid production. Three pronuclei that could be observed in the treated eggs under fluorescence microscope developed into triploid embryos. Some abnormal chromosome behavior was observed in heat shocked eggs.

  2. Multiple oligomeric structures of a bacterial small heat shock protein

    PubMed Central

    Mani, Nandini; Bhandari, Spraha; Moreno, Rodolfo; Hu, Liya; Prasad, B. V. Venkataram; Suguna, Kaza

    2016-01-01

    Small heat shock proteins are ubiquitous molecular chaperones that form the first line of defence against the detrimental effects of cellular stress. Under conditions of stress they undergo drastic conformational rearrangements in order to bind to misfolded substrate proteins and prevent cellular protein aggregation. Owing to the dynamic nature of small heat shock protein oligomers, elucidating the structural basis of chaperone action and oligomerization still remains a challenge. In order to understand the organization of sHSP oligomers, we have determined crystal structures of a small heat shock protein from Salmonella typhimurium in a dimeric form and two higher oligomeric forms: an 18-mer and a 24-mer. Though the core dimer structure is conserved in all the forms, structural heterogeneity arises due to variation in the terminal regions. PMID:27053150

  3. Synergistic Effects of Toxic Elements on Heat Shock Proteins

    PubMed Central

    Mahmood, Khalid; Mahmood, Qaisar; Irshad, Muhammad; Hussain, Jamshaid

    2014-01-01

    Heat shock proteins show remarkable variations in their expression levels under a variety of toxic conditions. A research span expanded over five decades has revealed their molecular characterization, gene regulation, expression patterns, vast similarity in diverse groups, and broad range of functional capabilities. Their functions include protection and tolerance against cytotoxic conditions through their molecular chaperoning activity, maintaining cytoskeleton stability, and assisting in cell signaling. However, their role as biomarkers for monitoring the environmental risk assessment is controversial due to a number of conflicting, validating, and nonvalidating reports. The current knowledge regarding the interpretation of HSPs expression levels has been discussed in the present review. The candidature of heat shock proteins as biomarkers of toxicity is thus far unreliable due to synergistic effects of toxicants and other environmental factors. The adoption of heat shock proteins as “suit of biomarkers in a set of organisms” requires further investigation. PMID:25136596

  4. Influence of heat shock on glycerol production in alcohol fermentation.

    PubMed

    Berovic, Marin; Pivec, Aleksandra; Kosmerl, Tatjana; Wondra, Mojmir; Celan, Stefan

    2007-02-01

    The influence of single and double heat shocks induced during the exponential growth phase of the Saccharomyces cerevisiae fermentation of cultivar Sauvignon Blanc grape must was examined. Rapid temperature changes from 18 degrees C to 34 degrees C have been applied. The effect of the duration of exposure to a high temperature has been analyzed. By the applications of a single heat shock and a double heat shock, up to 8.2 g l(-1) and 11.0 g l(-1) glycerol have been produced, respectively. To prevent the evaporation of fine wine bouquet compounds during the temperature changes, reflux coolers on the top of bioreactors have been employed. By using this method, glycerol production was increased by up to 65%. PMID:17368395

  5. Heat shock mediated labelling of Pseudomonas aeruginosa with quantum dots.

    PubMed

    Kumar, Natasha; Wiraja, Christian; Palanisamy, Kannan; Marsili, Enrico; Xu, Chenjie

    2016-06-01

    Biocompatible nanoparticles are good candidates to label bacteria for imaging and diagnosis purposes. A high labeling efficiency reduces the concentration of nanoparticles required for labeling and allows the labeled bacteria to be tracked for longer periods. This report explores the optimal labeling strategy for Pseudomonas aeruginosa, a common gram-negative opportunistic pathogen, with quantum dots. Three strategies including direct incubation, calcium chloride treatment, and heat shock are compared and the labeling efficiency is assessed through fluorescence microscopy and flow cytometry analysis. Of the three, heat shock is finally selected due to its comparable labeling efficiency and simplicity. Through the assay of the respiration rate of bacteria together with morphology analysis, the heat shock process does not show any negative effect over the cells activity even at sub-toxic concentrations. PMID:26962762

  6. The small heat shock proteins family: the long forgotten chaperones.

    PubMed

    Garrido, C; Paul, C; Seigneuric, R; Kampinga, H H

    2012-10-01

    Small heat shock proteins are a rather heterogeneous family of ATP-independent chaperones, some of which have been proven to block protein aggregation and help the cells to survive stressful conditions. Although much less studied than high molecular weight HSPs like HSP70/HSPA or HSP90/HSPC, their implication in physio-pathological processes and human diseases is now well evidenced, as it will be discussed in the different reviews of this special issue. In this mini-review we will just present a general introduction about the small heat shock proteins family. This article is part of a Directed Issue entitled: Small HSPs in physiology and pathology. PMID:22449631

  7. Heat shock and herpes virus: enhanced reactivation without untargeted mutagenesis

    SciTech Connect

    Lytle, C.D.; Carney, P.G.

    1988-01-01

    Enhanced reactivation of Ultraviolet-irradiated virus has been reported to occur in heat-shocked host cells. Since enhanced virus reactivation is often accompanied by untargeted mutagenesis, we investigated whether such mutagenesis would occur for herpes simplex virus (HSV) in CV-1 monkey kidney cells subjected to heat shock. In addition to expressing enhanced reactivation, the treated cells were transiently more susceptible to infection by unirradiated HSV. No mutagenesis of unirradiated HSV was found whether infection occurred at the time of increased susceptibility to infection or during expression of enhanced viral reactivation.

  8. Inbreeding interferes with the heat-shock response

    PubMed Central

    Franke, Kristin; Fischer, Klaus

    2015-01-01

    Inbreeding is typically detrimental to individual fitness, with negative effects being often exaggerated in stressful environments. However, the causal mechanisms underlying inbreeding depression in general and the often increased susceptibility to stress in particular are not well understood. We here test whether inbreeding interferes with the heat-shock response, comprising an important component of the stress response which may therefore underscore sensitivity to stress. To this end we subjected the tropical butterfly Bicyclus anynana to a full-factorial design with three temperatures and three levels of inbreeding, and measured the expression of heat-shock protein (HSP) 70 via qPCR. HSP70 expression increased after exposure to heat as compared with cold or control conditions. Most strikingly, inbreeding strongly interfered with the heat-shock response, with inbred individuals showing a very weak upregulation of HSP70 only. Our results thus indicate that, in our study organism, interference with the heat-shock response may be one mechanism underlying reduced fitness of inbred individuals, especially when exposed to stressful conditions. However, these indications need to be corroborated using a broader range of different temperatures, genes and taxa. PMID:25074571

  9. Heat shock proteins and the heat shock response during hyperthermia and its modulation by altered physiological conditions.

    PubMed

    Horowitz, Michal; Robinson, Sharon D M

    2007-01-01

    The fundamental functions of heat shock proteins (HSPs) are molecular chaperoning and cellular repair. There is little literature on the association between the numerous functions of HSPs and systemic integrative responses, particularly those controlled by the central nervous system. This chapter focuses on the role played by members of the HSP70 superfamily, universally recognized as cytoprotectants during heat stress, within the physiological context of hyperthermia and with its superimposition on situations of chronic stress. In the nucleus tractus solitarius, HSP70 levels enhance the sensitivity of sympathetic and parasympathetic arms of the autonomic nervous system to attenuate heat stroke-induced cerebral ischemia and hypotension. Chronic stressors that alter the heat shock response may affect the physiological profile during hyperthermic conditions. Upon aging, significantly lower HSP70 production is noted in the ventral paraventricular and lateral magnocellular nuclei. Likewise, results from cultured cells suggest that the age-related decline in HSP70 expression is constitutive and is due to decreased binding of the heat shock factor 1 (HSF-1) to the heat shock element (HSE) and diminished HSP70 transcription. These changes may be associated with decreased thermotolerance upon aging, although HSP70 production in response to other stressors is not affected. Heat acclimation (AC), in contrast, increases tissue reserves of HSP70 and accelerates the heat shock response. AC protects epithelial integrity, vascular reactivity and interactions with cellular signaling networks, enhancing protection and delaying thermal injury. The link between HSP70 and the immune system is discussed with respect to exercise. Exercise enhances the immune response via production of HSP72 in central and peripheral structures. At least in part, the effects of HSP72 in the brain are mediated via eHSP72-circulating HSPs providing a "danger signal" to activate the immune response. In

  10. Inhibition of Heat Shock Induction of Heat Shock Protein 70 and Enhancement of Heat Shock Protein 27 Phosphorylation by Quercetin Derivatives

    PubMed Central

    Wang, Rongsheng E.; Kao, Jeffrey L.-F.; Hilliard, Carolyn A.; Pandita, Raj K.; Roti, Joseph L. Roti; Hunt, Clayton R.; Taylor, John-Stephen

    2009-01-01

    Inhibitors of heat-induced heat shock protein 70 (HSP70)a expression have the potential to enhance the therapeutic effectiveness of heat induced radiosensitization of tumors. Among known small molecule inhibitors, quercetin has the advantage of being easily modified for structure-activity studies. Herein, we report the ability of five mono-methyl and five carbomethoxymethyl derivatives of quercetin to inhibit heat-induced HSP70 expression and enhance HSP27 phosphorylation in human cells. While quercetin and several derivatives inhibit HSP70 induction and enhance HSP27 phosphorylation at Ser78, other analogs selectively inhibit HSP70 induction without enhancing HSP27 phosphorylation that would otherwise aid in cell survival. We also show that good inhibitors of HSP70 induction are also good inhibitors of both CK2 and CamKII, kinases that are known to activate HSP70 expression by phosphorylation of heat shock transcription factor 1. Derivatives that show poor inhibition of either or both kinases are not good inhibitors of HSP70 induction, suggesting that quercetin’s effectiveness is due to its ability to inhibit both kinases. PMID:19296652

  11. Sequence characterization of heat shock protein gene of Cyclospora cayetanensis isolates from Nepal, Mexico, and Peru.

    PubMed

    Sulaiman, Irshad M; Torres, Patricia; Simpson, Steven; Kerdahi, Khalil; Ortega, Ynes

    2013-04-01

    We have described the development of a 2-step nested PCR protocol based on the characterization of the 70-kDa heat shock protein (HSP70) gene for rapid detection of the human-pathogenic Cyclospora cayetanensis parasite. We tested and validated these newly designed primer sets by PCR amplification followed by nucleotide sequencing of PCR-amplified HSP70 fragments belonging to 16 human C. cayetanensis isolates from 3 different endemic regions that include Nepal, Mexico, and Peru. No genetic polymorphism was observed among the isolates at the characterized regions of the HSP70 locus. This newly developed HSP70 gene-based nested PCR protocol provides another useful genetic marker for the rapid detection of C. cayetanensis in the future. PMID:22924935

  12. The effect of a type 3 and type 4 shock/shock interaction on heat transfer in the stagnation region

    NASA Technical Reports Server (NTRS)

    Wilson, Dennis

    1991-01-01

    One of the major engineering challenges in designing the National Aerospace Plane, NASP, is to overcome augmented heating on the intake cowl lip from shock/shock interactions. The shock/shock interaction arises when the bow shock from the craft's nose interferes with the bow shock from the cowl lip. Considering only the region immediately around the cowl lip, the problem geometry may be simplified as that of an oblique shock impinging on a bow shock from a circular cylinder. Edney classified six different interference patterns resulting from an oblique-shock/curved bow-shock interaction. Of these six types, type 3 and 4 are most significant in that augmented surface heat transfer may be ten to thirty times greater than the case without the shock/shock interaction. The objective was to begin to develop a mathematical model which is capable of predicting the effect of a type 3 and 4 shock/shock interaction in the stagnation region of an arbitrary 2-D body. This model must be capable of predicting the maximum surface heat flux and the surface stagnation point pressure once the outer (effectively inviscid) flowfield is given. Therefore, it must capture the unsteady physics of the impinging shear layer.

  13. Heat shock protein 90 is required for sexual and asexual development, virulence, and heat shock response in Fusarium graminearum.

    PubMed

    Bui, Duc-Cuong; Lee, Yoonji; Lim, Jae Yun; Fu, Minmin; Kim, Jin-Cheol; Choi, Gyung Ja; Son, Hokyoung; Lee, Yin-Won

    2016-01-01

    Eukaryotic cells repress global translation and selectively upregulate stress response proteins by altering multiple steps in gene expression. In this study, genome-wide transcriptome analysis of cellular adaptation to thermal stress was performed on the plant pathogenic fungus Fusarium graminearum. The results revealed that profound alterations in gene expression were required for heat shock responses in F. graminearum. Among these proteins, heat shock protein 90 (FgHsp90) was revealed to play a central role in heat shock stress responses in this fungus. FgHsp90 was highly expressed and exclusively localised to nuclei in response to heat stress. Moreover, our comprehensive functional characterisation of FgHsp90 provides clear genetic evidence supporting its crucial roles in the vegetative growth, reproduction, and virulence of F. graminearum. In particular, FgHsp90 performs multiple functions as a transcriptional regulator of conidiation. Our findings provide new insight into the mechanisms underlying adaptation to heat shock and the roles of Hsp90 in fungal development. PMID:27306495

  14. Heat shock protein 90 is required for sexual and asexual development, virulence, and heat shock response in Fusarium graminearum

    PubMed Central

    Bui, Duc-Cuong; Lee, Yoonji; Lim, Jae Yun; Fu, Minmin; Kim, Jin-Cheol; Choi, Gyung Ja; Son, Hokyoung; Lee, Yin-Won

    2016-01-01

    Eukaryotic cells repress global translation and selectively upregulate stress response proteins by altering multiple steps in gene expression. In this study, genome-wide transcriptome analysis of cellular adaptation to thermal stress was performed on the plant pathogenic fungus Fusarium graminearum. The results revealed that profound alterations in gene expression were required for heat shock responses in F. graminearum. Among these proteins, heat shock protein 90 (FgHsp90) was revealed to play a central role in heat shock stress responses in this fungus. FgHsp90 was highly expressed and exclusively localised to nuclei in response to heat stress. Moreover, our comprehensive functional characterisation of FgHsp90 provides clear genetic evidence supporting its crucial roles in the vegetative growth, reproduction, and virulence of F. graminearum. In particular, FgHsp90 performs multiple functions as a transcriptional regulator of conidiation. Our findings provide new insight into the mechanisms underlying adaptation to heat shock and the roles of Hsp90 in fungal development. PMID:27306495

  15. Expression of heat shock protein genes in insect stress responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The heat shock proteins (HSPs) that are abundantly expressed in insects are important modulators of insect survival. Expression of HSP genes in insects is not only developmentally regulated, but also induced by various stressors in order to confer protection against such stressors. The expression o...

  16. Circuit architecture explains functional similarity of bacterial heat shock responses

    NASA Astrophysics Data System (ADS)

    Inoue, Masayo; Mitarai, Namiko; Trusina, Ala

    2012-12-01

    Heat shock response is a stress response to temperature changes and a consecutive increase in amounts of unfolded proteins. To restore homeostasis, cells upregulate chaperones facilitating protein folding by means of transcription factors (TFs). We here investigate two heat shock systems: one characteristic to gram negative bacteria, mediated by transcriptional activator σ32 in E. coli, and another characteristic to gram positive bacteria, mediated by transcriptional repressor HrcA in L. lactis. We construct simple mathematical models of the two systems focusing on the negative feedbacks, where free chaperones suppress σ32 activation in the former, while they activate HrcA repression in the latter. We demonstrate that both systems, in spite of the difference at the TF regulation level, are capable of showing very similar heat shock dynamics. We find that differences in regulation impose distinct constraints on chaperone-TF binding affinities: the binding constant of free σ32 to chaperone DnaK, known to be in 100 nM range, set the lower limit of amount of free chaperone that the system can sense the change at the heat shock, while the binding affinity of HrcA to chaperone GroE set the upper limit and have to be rather large extending into the micromolar range.

  17. Characterization of alternatively spliced transcripts encoding heat shock transcription factor in cultured cells of the cabbage armyworm, Mamestra brassicae.

    PubMed

    Sonoda, Shoji; Tsumuki, Hisaaki

    2010-01-01

    A gene encoding heat shock transcription factor (HSF) was cloned and sequenced from cultured cells of the cabbage armyworm, Mamestra brassicae. The cDNA potentially encoded a 699-aa protein, with a calculated molecular weight of 77.8 kDa. Deduced amino acid identities to HSFs from Aedes aegypti and Drosophila melanogaster were 36 and 34%, respectively. Analysis of the genomic DNA revealed eight exons and three optional exons: a, b, and c. Exon a contained a premature in-frame stop codon that would generate a truncated protein. When the cells were exposed to high temperature or cadmium, no particular alternative transcripts showed significant up- or down-regulated expression relative to the total amount of the transcripts. These results suggest that alternative splicing may not be a principal mechanism for regulation of M. brassicae HSF gene expression in response to heat shock and cadmium. PMID:19750550

  18. Molecular characterization of the gene encoding an 18-kilodalton small heat shock protein associated with the membrane of Leuconostoc oenos.

    PubMed Central

    Jobin, M P; Delmas, F; Garmyn, D; Diviès, C; Guzzo, J

    1997-01-01

    In Leuconostoc oenos, different stresses such as heat, ethanol, and acid shocks dramatically induce the expression of an 18-kDa small heat shock protein called Lo 18. The corresponding gene (hsp18) was cloned from a genomic library of L. oenos constructed in Escherichia coli. A 2.3-kb DNA fragment carrying the hsp18 gene was sequenced. The hsp18 gene encodes a polypeptide of 148 amino acids with a calculated molecular mass of 16,938 Da. The Lo18 protein has a significant identity with small heat shock proteins of the alpha-crystallin family. The transcriptional start site was determined by primer extension. This experiment allowed us to identify the promoter region exhibiting high similarity to consensus promoter sequences of gram-positive bacteria, as well as E. coli. Northern blot analysis showed that hsp18 consists of a unique transcription unit of 0.6 kb. Moreover, hsp18 expression seemed to be controlled at the transcriptional level. This small heat shock protein was found to be peripherally associated with the membrane of L. oenos. PMID:9023938

  19. Inhibition of Heat Shock Protein 90 Prevents HIV Rebound.

    PubMed

    Joshi, Pheroze; Maidji, Ekaterina; Stoddart, Cheryl A

    2016-05-01

    HIV evades eradication because transcriptionally dormant proviral genomes persist in long-lived reservoirs of resting CD4(+) T cells and myeloid cells, which are the source of viral rebound after cessation of antiretroviral therapy. Dormant HIV genomes readily produce infectious virus upon cellular activation because host transcription factors activated specifically by cell stress and heat shock mediate full-length HIV transcription. The molecular chaperone heat shock protein 90 (Hsp90) is overexpressed during heat shock and activates inducible cellular transcription factors. Here we show that heat shock accelerates HIV transcription through induction of Hsp90 activity, which activates essential HIV-specific cellular transcription factors (NF-κB, NFAT, and STAT5), and that inhibition of Hsp90 greatly reduces gene expression mediated by these factors. More importantly, we show that Hsp90 controls virus transcription in vivo by specific Hsp90 inhibitors in clinical development, tanespimycin (17-(allylamino)-17-demethoxygeldanamycin) and AUY922, which durably prevented viral rebound in HIV-infected humanized NOD scid IL-2Rγ(-/-) bone marrow-liver-thymus mice up to 11 weeks after treatment cessation. Despite the absence of rebound viremia, we were able to recover infectious HIV from PBMC with heat shock. Replication-competent virus was detected in spleen cells from these nonviremic Hsp90 inhibitor-treated mice, indicating the presence of a tissue reservoir of persistent infection. Our novel findings provide in vivo evidence that inhibition of Hsp90 activity prevents HIV gene expression in replication-competent cellular reservoirs that would typically cause rebound in plasma viremia after antiretroviral therapy cessation. Alternating or supplementing Hsp90 inhibitors with current antiretroviral therapy regimens could conceivably suppress rebound viremia from persistent HIV reservoirs. PMID:26957545

  20. Inhibition of Heat Shock Protein 90 Prevents HIV Rebound*

    PubMed Central

    Joshi, Pheroze; Maidji, Ekaterina; Stoddart, Cheryl A.

    2016-01-01

    HIV evades eradication because transcriptionally dormant proviral genomes persist in long-lived reservoirs of resting CD4+ T cells and myeloid cells, which are the source of viral rebound after cessation of antiretroviral therapy. Dormant HIV genomes readily produce infectious virus upon cellular activation because host transcription factors activated specifically by cell stress and heat shock mediate full-length HIV transcription. The molecular chaperone heat shock protein 90 (Hsp90) is overexpressed during heat shock and activates inducible cellular transcription factors. Here we show that heat shock accelerates HIV transcription through induction of Hsp90 activity, which activates essential HIV-specific cellular transcription factors (NF-κB, NFAT, and STAT5), and that inhibition of Hsp90 greatly reduces gene expression mediated by these factors. More importantly, we show that Hsp90 controls virus transcription in vivo by specific Hsp90 inhibitors in clinical development, tanespimycin (17-(allylamino)-17-demethoxygeldanamycin) and AUY922, which durably prevented viral rebound in HIV-infected humanized NOD scid IL-2Rγ−/− bone marrow-liver-thymus mice up to 11 weeks after treatment cessation. Despite the absence of rebound viremia, we were able to recover infectious HIV from PBMC with heat shock. Replication-competent virus was detected in spleen cells from these nonviremic Hsp90 inhibitor-treated mice, indicating the presence of a tissue reservoir of persistent infection. Our novel findings provide in vivo evidence that inhibition of Hsp90 activity prevents HIV gene expression in replication-competent cellular reservoirs that would typically cause rebound in plasma viremia after antiretroviral therapy cessation. Alternating or supplementing Hsp90 inhibitors with current antiretroviral therapy regimens could conceivably suppress rebound viremia from persistent HIV reservoirs. PMID:26957545

  1. Bioinformatics evaluation of the possibility of heat shock proteins as autoantigens in multiple sclerosis based on molecular mimicry hypothesis.

    PubMed

    Ansari Qeshmi, Safa; Dabbagh, Fatemeh; Borhani Haghighi, Afshin; Ghasemi, Younes

    2016-06-15

    Molecular mimicry is the explanatory link between the heat shock proteins (HSPs) of infectious agents and triggering multiple sclerosis. Considering that there are many similarities between self- and bacterial-HSPs, the goal was to investigate a panel of 60- and 70kDa HSPs from a variety of bacteria in order to predict the role of each microorganism in triggering or progression of the disease under the molecular mimicry hypothesis. By clarifying the peptides meeting criteria for cross-reactivity and elucidating the role of each microorganism in MS pathogenesis, it would be easier to suggest more effective treatment and preventive strategies for this disease. PMID:27235356

  2. SHOCK HEATING OF THE MERGING GALAXY CLUSTER A521

    SciTech Connect

    Bourdin, H.; Mazzotta, P.; Markevitch, M.; Giacintucci, S.; Brunetti, G.

    2013-02-10

    A521 is an interacting galaxy cluster located at z = 0.247, hosting a low-frequency radio halo connected to an eastern radio relic. Previous Chandra observations hinted at the presence of an X-ray brightness edge at the position of the relic, which may be a shock front. We analyze a deep observation of A521 recently performed with XMM-Newton in order to probe the cluster structure up to the outermost regions covered by the radio emission. The cluster atmosphere exhibits various brightness and temperature anisotropies. In particular, two cluster cores appear to be separated by two cold fronts. We find two shock fronts, one that was suggested by Chandra and that is propagating to the east, and another to the southwestern cluster outskirt. The two main interacting clusters appear to be separated by a shock-heated region, which exhibits a spatial correlation with the radio halo. The outer edge of the radio relic coincides spatially with a shock front, suggesting that this shock is responsible for the generation of cosmic-ray electrons in the relic. The propagation direction and Mach number of the shock front derived from the gas density jump, M = 2.4 {+-} 0.2, are consistent with expectations from the radio spectral index, under the assumption of Fermi I acceleration mechanism.

  3. Shock Heating of the Merging Galaxy Cluster A521

    NASA Technical Reports Server (NTRS)

    Bourdin, H.; Mazzotta, P.; Markevitch, M.; Giacintucci, S.; Brunetti, G.

    2013-01-01

    A521 is an interacting galaxy cluster located at z = 0.247, hosting a low-frequency radio halo connected to an eastern radio relic. Previous Chandra observations hinted at the presence of an X-ray brightness edge at the position of the relic, which may be a shock front. We analyze a deep observation of A521 recently performed with XMM-Newton in order to probe the cluster structure up to the outermost regions covered by the radio emission. The cluster atmosphere exhibits various brightness and temperature anisotropies. In particular, two cluster cores appear to be separated by two cold fronts. We find two shock fronts, one that was suggested by Chandra and that is propagating to the east, and another to the southwestern cluster outskirt. The two main interacting clusters appear to be separated by a shock-heated region, which exhibits a spatial correlation with the radio halo. The outer edge of the radio relic coincides spatially with a shock front, suggesting that this shock is responsible for the generation of cosmic-ray electrons in the relic. The propagation direction and Mach number of the shock front derived from the gas density jump, M = 2.4 +/- 0.2, are consistent with expectations from the radio spectral index, under the assumption of Fermi I acceleration mechanism.

  4. Cloning of apg-2 encoding a novel member of heat shock protein 110 family.

    PubMed

    Kaneko, Y; Kimura, T; Kishishita, M; Noda, Y; Fujita, J

    1997-04-11

    Chinese hamster heat shock protein 110-encoding gene (hsp110), mouse apg-1 and human hsp70RY are structurally related genes, with the first two encoding about 110-kDa HSPs [Yoon et al. (1995) J. Biol. Chem. 270, 15725-15733; Kaneko et al. (1997) J. Biol. Chem., in press; Fathallah et al. (1993) J. Immunol. 151, 810-813]. Using apg-1 cDNA as a probe, we isolated a novel cDNA, apg-2 from a mouse testis cDNA library, which was highly homologous to human hsp70RY. However, the predicted amino acid (aa) sequence of APG-2 was longer (841 aa) than that of HSP70RY (701 aa) and comparable to those of HSP110 and APG-1. Northern blot analysis revealed that the expression of apg-2 transcripts was ubiquitous in various mouse tissues, and most abundant in the testis and ovary. While induction of hsp70 transcripts was observed in mouse TAMA26 Sertoli cells and NIH/3T3 fibroblasts on temperature shift from 37 degrees C to 42 degrees C (traditional heat shock) or from 32 degrees C to 39 degrees C, apg-2 transcripts were not induced under either condition. These results suggest that apg-2 is an isoform of mouse homolog of hsp70RY, but that it belongs to the hsp110 family instead of hsp70 family, and that it plays a role under non-stress conditions. PMID:9161406

  5. Small heat shock protein message in etiolated Pea seedlings under altered gravity

    NASA Astrophysics Data System (ADS)

    Talalaiev, O.

    Plants are subjected to various environmental changes during their life cycle To protect themselves against unfavorable influences plant cells synthesize several classes of small heat shock proteins sHsp ranging in size from 15 to 30 kDa This proteins are able to enhance the refolding of chemically denatured proteins in an ATP-independent manner in other words they can function as molecular chaperones The potential contribution of effects of space flight at the plant cellular and gene regulation level has not been characterized yet The object of our study is sHsp gene expression in etiolated Pisum sativum seedlings exposed to altered gravity and environmental conditions We designed primers to detect message for two inducible forms of the cytosolic small heat shock proteins sHsp 17 7 and sHsp 18 1 Applying the RT- PCR we explore sHsps mRNA in pea seedling cells subjected to two types of altered gravity achieved by centrifugation from 3 to 8g by clinorotation 2 rpm and temperature elevation 42oC Temperature elevation as the positive control significantly increased PsHspl7 7 PsHspl8 1 expression We investigate the expression of actin it was constant and comparable for unstressed controls for all variants Results are under discussion

  6. Shock-Bubble Heating of the Intracluster Medium

    NASA Astrophysics Data System (ADS)

    Friedman, Samuel H.; Heinz, S.; Churazov, E.

    2011-01-01

    Active galactic nuclei (AGN) Feedback via extragalactic jets requires a thermalization of the energy injected into the intracluster medium (ICM) in order for energy feedback to occur. Heinz and Churazov (2005) proposed a method using shock waves and previously inflated bubbles in the ICM to extract energy from the shock waves and turn the energy into rotational kinetic energy. This energy would decay and allow heating to occur elsewhere throughout the galaxy cluster. In this paper, we extend to three dimensions (3D) the previous work using hydrodynamic simulations. We also compare our results to previous related work done performed experimentally.

  7. Induction and characterization of heat shock proteins of Salmonella typhi and their reactivity with sera from patients with typhoid fever.

    PubMed Central

    Tang, S W; Abubakar, S; Devi, S; Puthucheary, S; Pang, T

    1997-01-01

    The heat shock protein (HSP) response of Salmonella typhi following exposure to elevated growth temperatures was studied. Three major proteins with molecular sizes of 58, 68, and 88 kDa were abundantly expressed when S. typhi cells were shifted from 37 to 45 degrees C and to 55 degrees C. These proteins were also constitutively expressed at 37 degrees C. Western blotting and immunoprecipitation studies with anti-HSP monoclonal antibodies revealed that the 58- and 68-kDa proteins were analogous to the GroEL and DnaK proteins, respectively, of Escherichia coli. These HSPs are also abundantly present in the outer membrane fraction of disrupted cells and, to a lesser extent, in the cytosol. Immunoblotting experiments with sera from patients with a culture-positive diagnosis of typhoid fever showed the presence of antibodies to these HSPs. Nine of twelve sera reacted with the 58-, 68-, and 88-kDa proteins, while three sera reacted only with the 68- and 88-kDa proteins. All 10 sera from healthy individuals showed no binding to these HSPs. In light of the well-documented roles of HSPs in the pathogenesis of microbial infections and as immunodominant antigens, these findings may be relevant for a better understanding of disease processes and for the future development of diagnostic and preventive strategies. PMID:9199477

  8. Guidelines for the nomenclature of the human heat shock proteins

    PubMed Central

    Hageman, Jurre; Vos, Michel J.; Kubota, Hiroshi; Tanguay, Robert M.; Bruford, Elspeth A.; Cheetham, Michael E.; Chen, Bin; Hightower, Lawrence E.

    2008-01-01

    The expanding number of members in the various human heat shock protein (HSP) families and the inconsistencies in their nomenclature have often led to confusion. Here, we propose new guidelines for the nomenclature of the human HSP families, HSPH (HSP110), HSPC (HSP90), HSPA (HSP70), DNAJ (HSP40), and HSPB (small HSP) as well as for the human chaperonin families HSPD/E (HSP60/HSP10) and CCT (TRiC). The nomenclature is based largely on the more consistent nomenclature assigned by the HUGO Gene Nomenclature Committee and used in the National Center of Biotechnology Information Entrez Gene database for the heat shock genes. In addition to this nomenclature, we provide a list of the human Entrez Gene IDs and the corresponding Entrez Gene IDs for the mouse orthologs. PMID:18663603

  9. Protein disorder reduced in Saccharomyces cerevisiae to survive heat shock.

    PubMed

    Vicedo, Esmeralda; Gasik, Zofia; Dong, Yu-An; Goldberg, Tatyana; Rost, Burkhard

    2015-01-01

    Recent experiments established that a culture of Saccharomyces cerevisiae (baker's yeast) survives sudden high temperatures by specifically duplicating the entire chromosome III and two chromosomal fragments (from IV and XII). Heat shock proteins (HSPs) are not significantly over-abundant in the duplication. In contrast, we suggest a simple algorithm to " postdict " the experimental results: Find a small enough chromosome with minimal protein disorder and duplicate this region. This algorithm largely explains all observed duplications. In particular, all regions duplicated in the experiment reduced the overall content of protein disorder. The differential analysis of the functional makeup of the duplication remained inconclusive. Gene Ontology (GO) enrichment suggested over-representation in processes related to reproduction and nutrient uptake. Analyzing the protein-protein interaction network (PPI) revealed that few network-central proteins were duplicated. The predictive hypothesis hinges upon the concept of reducing proteins with long regions of disorder in order to become less sensitive to heat shock attack. PMID:26673203

  10. Effect of heat shock on S6 phosphorylation during the development of Blastocladiella emersonii.

    PubMed

    da Silva, A M; Juliani, M H; Bonato, M C

    1987-11-01

    Changes in phosphorylation of ribosomal protein S6 during heat shock, induction of thermotolerance and recovery from heat shock at different stages of Blastocladiella emersonii development were investigated. Independently of the initial state of S6 phosphorylation (maximal or intermediate), a rapid and complete dephosphorylation of S6 is induced by heat shock and S6 remains unphosphorylated during the acquired thermotolerance. During recovery from heat shock rephosphorylation of S6 occurs always to the levels characteristic of that particular stage, coincidently with the turn off of heat shock protein synthesis. PMID:3454866

  11. Gut myoelectrical activity induces heat shock response in Escherichia coli and Caco-2 cells.

    PubMed

    Laubitz, Daniel; Jankowska, Alicja; Sikora, Anna; Woliński, Jarosław; Zabielski, Romuald; Grzesiuk, Elzbieta

    2006-09-01

    The heat shock response is associated with the intracellular expression of a number of highly conserved heat shock proteins (Hsps). According to their molecular size, Hsps have been divided into several groups, which are strongly conserved and show high homology between the species, e.g., Hsp70, MW 70 kDa (Lindquist & Craig, 1998; Morimoto, 1998; Jolly & Morimoto, 2000; Zylicz et al. 2001). In all organisms the Hsp expression under stress conditions is regulated at transcriptional level, e.g., in humans by the heat shock transcription factor Hsf1 (Morimoto, 1998; Wu, 1995), while in Escherichia coli by replacement of the sigma factor sigma(70) in RNA polymerase by the sigma factor sigma(32) (Gross, 1987). The Hsps allow cell survival under stress conditions by renaturating of denaturated proteins, protecting of stress-labile proteins, preventing protein aggregation (chaperone functions), and by degradation of damaged proteins (protease activities) (Lindquist & Craig, 1988; Morimoto, 1998; Jolly & Morimoto, 2000). They have also many housekeeping functions under non-stressful conditions during the cell cycle, growth, development, and differentiation (Morimoto, 1998). Among a number of plausible inducing factors already studied, extremely low artificial electromagnetic fields have been shown to induce stress response in various cells, such as expression of sigma(32) mRNA (Cairo et al. 1998) and induction of DnaJ and DnaK proteins in Eschericha coli (Chow & Tung, 2000); expression of hsp-16 gene in Caenorhabditis elegans (Miyakawa et al., 2001); induction of heat shock transcription factor Hsf1 and Hsp70, Hsp90 and Hsp27 in human cells (Lin et al. 1997; Lin et al. 1998; Goodman & Blank, 1998; Pipkin et al. 1999). Nevertheless, the role of endogenous electromagnetic fields, i.e., generated by electrically active cells within a body remains controversial. Heat shock proteins (Hsps) protect cells against various environmental and endogenous stressors. Cytoprotection

  12. Transcriptome Profiles of Populus euphratica upon Heat Shock stress

    PubMed Central

    Chen, Jinhuan; Yin, Weilun; Xia, Xinli

    2014-01-01

    Heat stress, which strongly affects plant performance and often results in reduced vegetative growth and yields depression, has become an increasingly serious global problem. Populus euphratica Oliv. which has been considered as a tree model for the study of plant response to abiotic stresses, could be resistant to an extremely wide environmental temperature range (–40 °C to 45 °C). Previous study is mainly focused on its gene regulation upon drought and salt stress. However, little is known about gene regulation at the global transcriptome level upon heat stress. To understand the gene network controlling heat stress in P. euphratica, a transcriptome sequencing using Illumina Hiseq 2000 was performed to generate a 10 gigabases depth for each sample in the tissue of leaf. 119,573 unigeneswere generated with an average length of 474 bp. Approximately 49,605 (41.49%) unigenes exhibited significantly different expressions between two libraries. Among these unigenes, 11,165 (9.34%) were upregulated and 38,440 (32.15%) were down regulated. Heat shock proteins classified as molecular chaperones showed a significant percentage (1.13%) in the up regulated group. Heat responsive genes, such as polyubiquitins, were over expressed in heat treated sample. GO enrichment analysis revealed that the Go terms for differentially expressed unigenes were significantly enriched in hormone-mediated signal, biological process regulation and metabolic process regulation. Our data revealed a global transcriptome picture of P. euphratica in response to heat shock. The identified potential heat stress-related transcripts can be used to infer the gene regulation networks underlying the molecular mechanisms of heat response in P. euphratica. PMID:25435796

  13. The Role of Heat Shock Proteins in Leukemia.

    PubMed

    Kliková, K; Pilchova, I; Stefanikova, A; Hatok, J; Dobrota, D; Racay, P

    2016-01-01

    Heat shock proteins (HSPs) HSP27, HSP70 and HSP90 are molecular chaperones; their expression is increased after exposure of cells to conditions of environmental stress, including heat shock, heavy metals, oxidative stress, or pathologic conditions, such as ischemia, infection, and inflammation. Their protective function is to help the cell cope with lethal conditions. The HSPs are a class of proteins which, in normal cells, are responsible for maintaining homeostasis, interacting with diverse protein substrates to assist in their folding, and preventing the appearance of folding intermediates that lead to misfolded or damaged molecules. They have been shown to interact with different key apoptotic proteins and play a crucial role in regulating apoptosis. Several HSPs have been demonstrated to directly interact with various components of tightly regulated caspase-dependent programmed cell death. These proteins also affect caspase-independent apoptosis by interacting with apoptogenic factors. Heat shock proteins are aberrantly expressed in hematological malignancies. Because of their prognostic implications and functional role in leukemias, HSPs represent an interesting target for antileukemic therapy. This review will describe different molecules interacting with anti-apoptotic proteins HSP70 and HSP90, which can be used in cancer therapy based on their inhibition. PMID:26879061

  14. Metabolite changes associated with heat shocked avian fibroblast mitochondria.

    PubMed

    Schlesinger, M J; Ryan, C; Chi, M M; Carter, J G; Pusateri, M E; Lowry, O H

    1997-03-01

    A previous report from our laboratory (Collier et al 1993) showed that the elongated tubules of mitochondria in the cytoplasm of cultured chicken embryo fibroblasts collapsed to irregularly shaped structures surrounding the nuclear membrane after a 1 h heat shock treatment. The normal mitochondrial morphology reappeared upon removal of the thermal stress. We have now determined that several changes occurred in mitochondrial-related metabolites under these same heat shock and recovery conditions. Among these were significant decreases in the levels of fumarate and malate and increases in the amounts of aspartate and glutamate. In contrast, other intermediates of the tri-carboxylic acid cycle were unaltered as were levels of ATP and phosphocreatine. The changes observed might result from heat shock-induced changes in enzyme activities of the mitochondria, from alterations in the membrane-embedded specialized carrier proteins that transport metabolites between cytosol and mitochondria or from a disorganization of the electron-transport system normally coupled to oxidative metabolism. The rapid recovery, however, suggested that these changes were transient and readily reversible. PMID:9250392

  15. Fibronectin-binding antigen 85 and the 10-kilodalton GroES-related heat shock protein are the predominant TH-1 response inducers in leprosy contacts.

    PubMed

    Launois, P; N'Diaye, M N; Cartel, J L; Mane, I; Drowart, A; Van Vooren, J P; Sarthou, J L; Huygen, K

    1995-01-01

    Peripheral blood mononuclear cells from 27 healthy leprosy contacts were analyzed for lymphoproliferation and TH-1 cytokine secretion (interleukin-2 and gamma interferon) in response to heat shock proteins with molecular masses of 65, 18, and 10 kDa from Mycobacterium leprae and the 30-32-kDa antigen 85 (Ag 85) from Mycobacterium bovis BCG. Cells from 18 and 19 of 19 lepromin-positive contacts proliferated or produced TH-1 cytokines in response to the M. leprae 10-kDa protein and to Ag 85, respectively. Limiting-dilution analysis for two lepromin-positive contacts indicated that about one-third of M. leprae-reactive T cells displayed specificity to the M. leprae 10-kDa protein and Ag 85. The M. leprae 65- and 18-kDa proteins were less potent TH-1 response inducers: gamma interferon and interleukin-2 could be measured in 14 and 19 lepromin-positive contacts, respectively. In contrast, very low or undetectable proliferative and cytokine responses were found for 8 lepromin-negative contacts. Our data demonstrate that the fibronectin-binding Ag 85 and the 10-kDa GroES homolog are powerful mycobacterial TH-1 response inducers in the vast majority of lepromin-positive contacts and suggest that they might be valuable candidates for a future subunit vaccine. PMID:7806388

  16. Competition between shock and turbulent heating in coronal loop system

    NASA Astrophysics Data System (ADS)

    Matsumoto, Takuma

    2016-08-01

    2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfvén waves excited in the photosphere is the target of the present study. The coronal structure is reproduced in our simulations as a natural consequence of the transportation and dissipation of Alfvén waves. Further, the coronal structure is maintained as the spatial resolution is changed from 25 to 3 km, although the temperature at the loop top increases with the spatial resolution. The heating mechanisms change gradually across the magnetic canopy at a height of 4 Mm. Below the magnetic canopy, both the shock and the MHD turbulence are dominant heating processes. Above the magnetic canopy, the shock heating rate reduces to less than 10 % of the total heating rate while the MHD turbulence provides significant energy to balance the radiative cooling and thermal conduction loss or gain. The importance of compressibility shown in the present study would significantly impact on the prospects of successful MHD turbulence theory in the solar chromosphere.

  17. A heat shock transcription factor in pea is differentially controlled by heat and virus replication.

    PubMed

    Aranda, M A; Escaler, M; Thomas, C L; Maule, A J

    1999-10-01

    Since some heat-inducible genes [heat shock (hs) genes] can be induced by virus infection in pea [e.g. Hsp70; Aranda et al. 1996, Proc. Natl Acad. Sci. USA 93, 15289-15293], we have investigated the effect that heat and virus replication may have on the expression of a heat-shock transcription factor gene (Hsf). We have characterized what appears to be the only member of the Hsf family in pea, PsHsfA. Similar to Hsp70, PsHsfA is heat-inducible in vegetative and embryonic tissues, which is concordant with the presence of heat shock elements (HSEs) and stress responsive elements (STREs) on its promoter sequence. The expression of PsHsfA during virus replication was studied in pea cotyledons and leaves, and compared to that of Hsp70. In situ hybridization experiments showed that whereas Hsp70 is induced, there is no detectable increased accumulation of PsHsfA RNA associated with the replication of pea seed-borne mosaic potyvirus (PSbMV). These experiments indicate that there is a selective control of virus-induced hs gene expression, and suggest that different regulatory pathways control hs gene expression during heat shock and virus replication. PMID:10571875

  18. A heat shock protein 90 β isoform involved in immune response to bacteria challenge and heat shock from Miichthys miiuy.

    PubMed

    Wei, Tao; Gao, Yunhang; Wang, Rixin; Xu, Tianjun

    2013-08-01

    Heat shock protein 90 (HSP90) is highly conserved molecular chaperone that plays a critical role in cellular stress response. In this study, we reported the identification and functional analysis of a heat shock protein 90 gene from miiuy croaker (designated Mimi-HSP90). Mimi-HSP90 contained five conserved HSP90 protein family signatures and shared 89.6%-99.5% similarity with other known HSP90 β isoform. Homology analysis and structure comparison further indicated that Mimi-HSP90 should be β isoform member of the HSP90 family. The molecular evolutionary analysis showed that HSP90 was under an overall strong purifying select pressure among fish species. Mimi-HSP90 gene was constitutively expressed in ten examined tissues, and the expression level of liver was higher than in other tissues. The expression level of Mimi-HSP90 gene under bacterial infection and heat shock were analyzed by real-time quantitative RT-PCR, resulted in significant changes in liver, spleen, and kidney tissues. The purified recombinant pET-HSP90 protein was used to produce the polyclonal antibody in mice. The specificity of the antibody was determined by Western blot analysis. All results suggested that Mimi-HSP90 was involved in thermal stress and immune response in miiuy croaker. PMID:23684810

  19. Identification of Ca2+-dependent calmodulin-binding proteins in rat spermatogenic cells as complexes of the heat-shock proteins.

    PubMed

    Moriya, Megumi; Ochiai, Masanori; Yuasa, Hajime J; Suzuki, Norio; Yazawa, Michio

    2004-11-01

    Ca2+-calmodulin (CaM)-binding proteins in rat testes were characterized by assays for CaM-binding activity using the CaM-overlay method on transblots of electrophoresed gels and purification by gel-filtration, ion exchange, and adsorption chromatographies. A major CaM-binding protein complex (CaMBP) was identified and found to be comprised of three proteins with molecular masses 110, 100, and 70 kDa. Amino acid sequence analyses of lysylendopeptidase digests from these proteins indicated that all of the constituents of CaMBP are very similar to the members of the heat-shock protein family, i.e., the 110-kDa protein is similar to the APG-2/94 kDa rat ischemia-responsive protein, the 100-kDa protein is similar to the rat counterpart of the mouse APG-1/94 kDa osmotic stress protein, and the 70-kDa protein is similar to the rat testis-specific major heat-shock protein (HSP70). Immunohistochemistry using anti-CaMBP and anti-CaM antibodies demonstrated that CaMBP was co-localized with CaM in the cytoplasm of pachytene spermatocytes and nuclei of round spermatids. In addition, CaMBP, but not CaM, was localized at a high level in the residual bodies of elongated spermatids. The possible relevance of CaMBP to regulation of cell cycle progression and spermatogenesis is discussed in this paper. PMID:15349844

  20. Molecular cloning and expression of a heat-shock cognate 70 (hsc70) gene from swordtail fish ( Xiphophorus helleri)

    NASA Astrophysics Data System (ADS)

    Li, Ningqiu; Fu, Xiaozhe; Han, Jingang; Shi, Cunbin; Huang, Zhibin; Wu, Shuqin

    2013-07-01

    Heat shock proteins are a family of molecular chaperones that are involved in many aspects of protein homeostasis. In the present study, a full-length cDNA, encoding the constitutively expressed 70-kDa heat shock cognate protein (Hsc70), was isolated from swordtail fish ( Xiphophorus helleri) and designated as XheHsc70. The Xhehsc70 cDNA was 2 104 bp long with an open reading frame of 1 941 bp, and it encoded a protein of 646 amino acids with a theoretical molecular weight of 70.77 kDa and an isoelectric point of 5.04. The deduced amino acid sequence shared 94.1%-98.6% identities with the Hsc70s from a number of other fish species. Tissue distribution results show that the Xhehsc70 mRNA was expressed in brain, heart, head kidney, kidney, spleen, liver, muscle, gill, and peripheral blood. After immunization with formalin-killed Vibrio alginolyticus cells there was a significant increase in the Xhehsc70 mRNA transcriptional level in the head kidney of the vaccinated fish compared with in the control at 6, 12, 24, and 48 h as shown by quantitative real time RT-PCR. Based on an analysis of the amino acid sequence of XheHsc70, its phylogeny, and Xhehsc70 mRNA expression, XheHsc70 was identified as a member of the cytoplasmic Hsc70 (constitutive) subfamily of the Hsp70 family of heat shock proteins, suggesting that it may play a role in the immune response. The Xhehsc70 cDNA sequence reported in this study was submitted to GenBank under the accession number JF739182.

  1. Heat shock response improves heterologous protein secretion in Saccharomyces cerevisiae.

    PubMed

    Hou, Jin; Osterlund, Tobias; Liu, Zihe; Petranovic, Dina; Nielsen, Jens

    2013-04-01

    The yeast Saccharomyces cerevisiae is a widely used platform for the production of heterologous proteins of medical or industrial interest. However, heterologous protein productivity is often low due to limitations of the host strain. Heat shock response (HSR) is an inducible, global, cellular stress response, which facilitates the cell recovery from many forms of stress, e.g., heat stress. In S. cerevisiae, HSR is regulated mainly by the transcription factor heat shock factor (Hsf1p) and many of its targets are genes coding for molecular chaperones that promote protein folding and prevent the accumulation of mis-folded or aggregated proteins. In this work, we over-expressed a mutant HSF1 gene HSF1-R206S which can constitutively activate HSR, so the heat shock response was induced at different levels, and we studied the impact of HSR on heterologous protein secretion. We found that moderate and high level over-expression of HSF1-R206S increased heterologous α-amylase yield 25 and 70 % when glucose was fully consumed, and 37 and 62 % at the end of the ethanol phase, respectively. Moderate and high level over-expression also improved endogenous invertase yield 118 and 94 %, respectively. However, human insulin precursor was only improved slightly and this only by high level over-expression of HSF1-R206S, supporting our previous findings that the production of this protein in S. cerevisiae is not limited by secretion. Our results provide an effective strategy to improve protein secretion and demonstrated an approach that can induce ER and cytosolic chaperones simultaneously. PMID:23208612

  2. Heat shock response for ischemic kidney preservation and transplantation.

    PubMed

    Kaneko, H; Perdrizet, G A; Schweizer, R T

    1993-01-01

    The heat shock response (HSR) is a form of stress conditioning during which reversible changes in cellular metabolism are rapidly induced by brief exposure to supra-physiologic levels of heat. The nature of these adaptive adjustments has been widely investigated and has received much attention in molecular biology and cancer research. Recent evidence indicates that a basic form of this stress response exists at the cellular level of virtually every organism. Although the physiological phenomenon of HSR is complex, it is well known that it can induce specific proteins, known as heat shock proteins (HSP's), which are not normally synthesized. HSP's become the major proteins synthesized during the heat shock response while normal protein synthesis is suppressed. In addition, the HSR has been demonstrated to confer a transient resistance to the organism to subsequent episodes of stress. Recently it has been reported that the HSR confers protection against cold ischemic injury and extends the cold preservation time of the rat kidney to 48 hours. In this study, we have applied the concept of HSR to the preservation, and transplantation of warm ischemically injured pig kidneys. Since there is a serious shortage of cadaver kidneys available for transplantation worldwide, this number would increase if warm ischemic kidneys could be utilized. However with present methods of organ recovery and preservation, such kidneys are not likely to function after transplantation even if they were removed. We hypothesized that the application of a thermal stress to pig kidneys prior to organ procurement and preservation will enhance the organs' ability to function after warm ischemic injury. PMID:8352637

  3. The Molecular Evolution of the Small Heat-Shock Proteins in Plants

    PubMed Central

    Waters, E. R.

    1995-01-01

    The small heat-shock proteins have undergone a tremendous diversification in plants; whereas only a single small heat-shock protein is found in fungi and many animals, over 20 different small heat-shock proteins are found in higher plants. The small heat-shock proteins in plants have diversified in both sequence and cellular localization and are encoded by at least five gene families. In this study, 44 small heat-shock protein DNA and amino acid sequences were examined, using both phylogenetic analysis and analysis of nucleotide substitution patterns to elucidate the evolutionary history of the small heat-shock proteins. The phylogenetic relationships of the small heat-shock proteins, estimated using parsimony and distance methods, reveal that gene duplication, sequence divergence and gene conversion have all played a role in the evolution of the small heat-shock proteins. Analysis of nonsynonymous substitutions and conservative and radical replacement substitutions (in relation to hydrophobicity) indicates that the small heat-shock protein gene families are evolving at different rates. This suggests that the small heat-shock proteins may have diversified in function as well as in sequence and cellular localization. PMID:8647410

  4. Alpha subunit of eukaryotic translational initiation factor-2 is a heat-shock protein.

    PubMed

    Colbert, R A; Hucul, J A; Scorsone, K A; Young, D A

    1987-12-15

    The use of ultra high resolution giant two-dimensional gel electrophoresis has expanded the number of recognizable heat-shock proteins to 68 inductions in rat thymic lymphocytes, many of which are among the less abundant cellular proteins (Maytin, E. V., Colbert, R. A., and Young, D. A. (1985) J. Biol. Chem. 260, 2384-2392). Previous studies also show that cells receiving a prior heat shock recover more rapidly from the inhibition of protein synthesis induced by a second heat shock. In this report we use a monoclonal antibody to identify the alpha subunit of eukaryotic initiation factor-2 (eIF-2 alpha) as a heat-shock protein. Its relative rate of synthesis increases approximately 40% in the 2nd h and 5-fold in the 4th h of a continuous heat shock and is stimulated more dramatically, 15-fold, in the 3rd h of recovery from a 1-h heat shock. These results suggest that the induction of eIF-2 alpha in the heat-shock response may be important for restoring the cell's ability to initiate protein synthesis. In addition to identifying a function for one of the heat-shock proteins, our findings draw attention to the likelihood that other low-abundance heat-shock proteins may play critical roles in the heat-shock response. PMID:3500171

  5. Integrative analysis of the heat shock response in Aspergillus fumigatus

    PubMed Central

    2010-01-01

    Background Aspergillus fumigatus is a thermotolerant human-pathogenic mold and the most common cause of invasive aspergillosis (IA) in immunocompromised patients. Its predominance is based on several factors most of which are still unknown. The thermotolerance of A. fumigatus is one of the traits which have been assigned to pathogenicity. It allows the fungus to grow at temperatures up to and above that of a fevered human host. To elucidate the mechanisms of heat resistance, we analyzed the change of the A. fumigatus proteome during a temperature shift from 30°C to 48°C by 2D-fluorescence difference gel electrophoresis (DIGE). To improve 2D gel image analysis results, protein spot quantitation was optimized by missing value imputation and normalization. Differentially regulated proteins were compared to previously published transcriptome data of A. fumigatus. The study was augmented by bioinformatical analysis of transcription factor binding sites (TFBSs) in the promoter region of genes whose corresponding proteins were differentially regulated upon heat shock. Results 91 differentially regulated protein spots, representing 64 different proteins, were identified by mass spectrometry (MS). They showed a continuous up-, down- or an oscillating regulation. Many of the identified proteins were involved in protein folding (chaperones), oxidative stress response, signal transduction, transcription, translation, carbohydrate and nitrogen metabolism. A correlation between alteration of transcript levels and corresponding proteins was detected for half of the differentially regulated proteins. Interestingly, some previously undescribed putative targets for the heat shock regulator Hsf1 were identified. This provides evidence for Hsf1-dependent regulation of mannitol biosynthesis, translation, cytoskeletal dynamics and cell division in A. fumigatus. Furthermore, computational analysis of promoters revealed putative binding sites for an AP-2alpha-like transcription factor

  6. Global transcriptome analysis of the heat shock response ofshewanella oneidensis

    SciTech Connect

    Gao, Haichun; Wang, Sarah; Liu, Xueduan; Yan, Tinfeng; Wu, Liyou; Alm, Eric; Arkin, Adam P.; Thompson, Dorothea K.; Zhou, Jizhong

    2004-04-30

    Shewanella oneidensis is an important model organism for bioremediation studies because of its diverse respiratory capabilities. However, the genetic basis and regulatory mechanisms underlying the ability of S. oneidensis to survive and adapt to various environmentally relevant stresses is poorly understood. To define this organism's molecular response to elevated growth temperatures, temporal gene expression profiles were examined in cells subjected to heat stress using whole-genome DNA microarrays for S. oneidensis MR-1. Approximately 15 percent (711) of the predicted S. oneidensis genes represented on the microarray were significantly up- or down-regulated (P < 0.05) over a 25-min period following shift to the heat shock temperature (42 C). As expected, the majority of S. oneidensis genes exhibiting homology to known chaperones and heat shock proteins (Hsps) were highly and transiently induced. In addition, a number of predicted genes encoding enzymes in glycolys is and the pentose cycle, [NiFe] dehydrogenase, serine proteases, transcriptional regulators (MerR, LysR, and TetR families), histidine kinases, and hypothetical proteins were induced in response to heat stress. Genes encoding membrane proteins were differentially expressed, suggesting that cells possibly alter their membrane composition or structure in response to variations in growth temperature. A substantial number of the genes encoding ribosomal proteins displayed down-regulated co-expression patterns in response to heat stress, as did genes encoding prophage and flagellar proteins. Finally, based on computational comparative analysis of the upstream promoter regions of S.oneidensis heat-inducible genes, a putative regulatory motif, showing high conservation to the Escherichia coli sigma 32-binding consensus sequence, was identified.

  7. Electron heating in a Monte Carlo model of a high Mach number, supercritical, collisionless shock

    NASA Technical Reports Server (NTRS)

    Ellison, Donald C.; Jones, Frank C.

    1987-01-01

    Preliminary work in the investigation of electron injection and acceleration at parallel shocks is presented. A simple model of electron heating that is derived from a unified shock model which includes the effects of an electrostatic potential jump is described. The unified shock model provides a kinetic description of the injection and acceleration of ions and a fluid description of electron heating at high Mach number, supercritical, and parallel shocks.

  8. Paeoniflorin, a novel heat shock protein–inducing compound

    PubMed Central

    Yan, Dai; Saito, Kiyoto; Ohmi, Yuri; Fujie, Noriyo; Ohtsuka, Kenzo

    2004-01-01

    Heat shock proteins (HSPs) are induced by various physical, chemical, and biological stresses. HSPs are known to function as molecular chaperones, and they not only regulate various processes of protein biogenesis but also function as lifeguards against proteotoxic stresses. Because it is very useful to discover nontoxic chaperone-inducing compounds, we searched for them in herbal medicines. Some herbal medicines had positive effects on the induction of HSPs (Hsp70, Hsp40, and Hsp27) in cultured mammalian cells. We next examined 2 major constituents of these herbal medicines, glycyrrhizin and paeoniflorin, with previously defined chemical structures. Glycyrrhizin had an enhancing effect on the HSP induction by heat shock but could not induce HSPs by itself. In contrast, paeoniflorin had not only an enhancing effect but also an inducing effect by itself on HSP expression. Thus, paeoniflorin might be termed a chaperone inducer and glycyrrhizin a chaperone coinducer. Treatment of cells with paeoniflorin but not glycyrrhizin resulted in enhanced phosphorylation and acquisition of the deoxyribonucleic acid–binding ability of heat shock transcription factor 1 (HSF1), as well as the formation of characteristic HSF1 granules in the nucleus, suggesting that the induction of HSPs by paeoniflorin is mediated by the activation of HSF1. Also, thermotolerance was induced by treatment with paeoniflorin but not glycyrrhizin. Paeoniflorin had no toxic effect at concentrations as high as 80 μg/ mL (166.4 μM). To our knowledge, this is the first report on the induction of HSPs by herbal medicines. PMID:15633296

  9. Associations between heat shock protein 70 genetic polymorphisms and calving traits in crossbred Brahman cows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stressors such as heat, cold, toxins, and oxygen deprivation are known to induce heat shock proteins. Genetic polymorphisms associated with heat shock protein genes have been associated with decreased male and female fertility. Our objectives were to 1) confirm single nucleotide polymorphisms (SNP) ...

  10. Intra-binary Shock Heating of Black Widow Companions

    NASA Astrophysics Data System (ADS)

    Romani, Roger W.; Sanchez, Nicolas

    2016-09-01

    The low-mass companions of evaporating binary pulsars (black widows and similar) are strongly heated on the side facing the pulsar. However, in high-quality photometric and spectroscopic data, the heating pattern does not match that expected for direct pulsar illumination. Here we explore a model where the pulsar power is intercepted by an intra-binary shock (IBS) before heating the low-mass companion. We develop a simple analytic model and implement it in the popular “ICARUS” light curve code. The model is parameterized by the wind momentum ratio β and the companion wind speed {f}v{v}{{orb}}, and assumes that the reprocessed pulsar wind emits prompt particles or radiation to heat the companion surface. We illustrate an interesting range of light curve asymmetries controlled by these parameters. The code also computes the IBS synchrotron emission pattern, and thus can model black widow X-ray light curves. As a test, we apply the results to the high-quality asymmetric optical light curves of PSR J2215+5135; the resulting fit gives a substantial improvement upon direct heating models and produces an X-ray light curve consistent with that seen. The IBS model parameters imply that at the present loss rate, the companion evaporation has a characteristic timescale of {τ }{{evap}}≈ 150 Myr. Still, the model is not fully satisfactory, indicating that there are additional unmodeled physical effects.

  11. Increased proteolysis of diphtheria toxin by human monocytes after heat shock: a subsidiary role for heat-shock protein 70 in antigen processing

    PubMed Central

    Polla, Barbara S; Gabert, Françoise; Peyrusse, Brigitte M-N; Jacquier-Sarlin, Muriel R

    2007-01-01

    The expression of heat-shock proteins (hsp) increases after exposure to various stresses including elevated temperatures, oxidative injury, infection and inflammation. As molecular chaperones, hsp have been shown to participate in antigen processing and presentation, in part through increasing the stability and expression of major histocompatibility complex molecules. Heat shock selectively increases human T-cell responses to processed antigen, but does not affect T-cell proliferation induced by non-processed antigens. Here, we have analysed the mechanisms by which stress such as heat shock, and the ensuing hsp over-expression affect the processing of diphtheria toxin (DT) in peripheral blood monocytes. We found that heat shock increased DT proteolysis in endosomes and lysosomes while the activities of the cathepsins B and D, classically involved in DT proteolysis, were decreased. These effects correlated with the heat-shock-mediated increase in hsp 70 expression observed in endosomes and lysosomes. Actinomycin D or blocking anti-hsp 70 antibodies abolished the heat-shock-mediated increase in DT proteolysis. These data indicate that the increased expression of hsp 70 constitutes a subsidiary mechanism that facilitates antigen proteolysis in stressed cells. Confirming these data, presentation by formaldehyde-fixed cells of DT proteolysates that were obtained with endosomes and lysosomes from heat-shocked peripheral blood monocytes showed higher stimulation of T cells than those generated with endosomes and lysosomes from control peripheral blood monocytes. PMID:17116171

  12. Heat-shock response in Arabidopsis thaliana explored by multiplexed quantitative proteomics using differential metabolic labeling.

    PubMed

    Palmblad, Magnus; Mills, Davinia J; Bindschedler, Laurence V

    2008-02-01

    We have developed a general method for multiplexed quantitative proteomics using differential metabolic stable isotope labeling and mass spectrometry. The method was successfully used to study the dynamics of heat-shock response in Arabidopsis thaliana. A number of known heat-shock proteins were confirmed, and some proteins not previously associated with heat shock were discovered. The method is applicable in stable isotope labeling and allows for high degrees of multiplexing. PMID:18189342

  13. DNA damage-responsive Drosophila melanogaster gene is also induced by heat shock

    SciTech Connect

    Vivino, A.A.; Smith, M.D.; Minton, K.W.

    1986-12-01

    A gene isolated by screening Drosophila melanogaster tissue culture cells for DNA damage regulation was also found to be regulated by heat shock. After UV irradiation or heat shock, induction is at the transcriptional level and results in the accumulation of a 1.0-kilobase polyadenylated transcript. The restriction map of the clone bears no resemblance to the known heat shock genes, which are shown to be uninduced by UV irradiation.

  14. KPNA3-knockdown eliminates the second heat shock protein peak associated with the heat shock response of male silkworm pupae (Bombyx mori) by reducing heat shock factor transport into the nucleus.

    PubMed

    Li, Jun; Wei, Guoqing; Wang, Lei; Qian, Cen; Li, Kedong; Zhang, Congfen; Dai, Lishang; Sun, Yu; Liu, Dongran; Zhu, Baojian; Liu, Chaoliang

    2016-01-10

    In this study, we investigated the role of karyopherin alpha 3 in the heat shock response in male silkworm pupae. Karyopherin alpha recognizes the classical nuclear location sequence on proteins and transports them into the nucleus by forming a trimetric complex with karyopherin beta. Three predicted karyopherin alphas (KPNA1, KPNA2 and KPNA3) have been identified from the silkworm Bombyx mori. Pull-down assay result showed that KPNA3 can pull down heat shock transcription factor (HSF) from proteins extracted from tissues using non-denature lysis buffer. After 45 °C heat shock on male B. mori pupae for 30 min, we identified two heat shock protein (HSP) mRNA expression peaks correlating with HSP19.9, HSP20.4 and HSP25.4 at 4 h (peak 1) and 24 h (peak 2). The second peak was eliminated after knockdown of KPNA3. Similar results were obtained following knockdown of HSF, which is the trans-activating factor of heat shock. However, KPNA3 knockdown was not accompanied by the decreased HSF protein levels at 24 h after heat shock which were observed following HSF knockdown. We also expressed recombinant protein GST-KPNA3 and His-HSF in Escherichia coli to perform GST pull-down assay and the result confirmed the interaction between KPNA3 and HSF. We concluded that KPNA3 knockdown eliminates the second heat shock protein peak in the heat shock response of male silkworm pupae by reducing HSF transport into the nucleus. PMID:26367326

  15. Heat shock-induced interactions among nuclear HSFs detected by fluorescence cross-correlation spectroscopy

    SciTech Connect

    Pack, Chan-Gi; Ahn, Sang-Gun

    2015-07-31

    The cellular response to stress is primarily controlled in cells via transcriptional activation by heat shock factor 1 (HSF1). HSF1 is well-known to form homotrimers for activation upon heat shock and subsequently bind to target DNAs, such as heat-shock elements, by forming stress granules. A previous study demonstrated that nuclear HSF1 and HSF2 molecules in live cells interacted with target DNAs on the stress granules. However, the process underlying the binding interactions of HSF family in cells upon heat shock remains unclear. This study demonstrate for the first time that the interaction kinetics among nuclear HSF1, HSF2, and HSF4 upon heat shock can be detected directly in live cells using dual color fluorescence cross-correlation spectroscopy (FCCS). FCCS analyses indicated that the binding between HSFs was dramatically changed by heat shock. Interestingly, the recovery kinetics of interaction between HSF1 molecules after heat shock could be represented by changes in the relative interaction amplitude and mobility. - Highlights: • The binding interactions among nuclear HSFs were successfully detected. • The binding kinetics between HSF1s during recovery was quantified. • HSF2 and HSF4 strongly formed hetero-complex, even before heat shock. • Nuclear HSF2 and HSF4 bound to HSF1 only after heat shock.

  16. Heat shock protein 60 acts as a receptor for the Listeria adhesion protein in Caco-2 cells.

    PubMed

    Wampler, Jennifer L; Kim, Kwang-Pyo; Jaradat, Ziad; Bhunia, Arun K

    2004-02-01

    The 104-kDa Listeria adhesion protein (LAP) in Listeria monocytogenes is involved in binding to various mammalian cell lines. However, the receptor that interacts with LAP in eukaryotic cells is unknown. In this study, scanning immunoelectron microscopy qualitatively demonstrated greater binding capacity of wild-type (WT) L. monocytogenes strain (F4244) than a LAP-deficient mutant strain (KB208) to Caco-2 cells. The goal of this study was identification of the host cell receptor for LAP. Using a Western blot ligand overlay assay, we identified a protein of 58 kDa to be the putative receptor for LAP from Caco-2 cells. N-terminal sequencing and subsequent database search identified this protein as heat shock protein 60 (Hsp60). Modified immunoseparation with protein A-Sepharose beads bound to the LAP-specific monoclonal antibody H7 (MAb-H7) and a sequential incubation with LAP preparation and Caco-2 lysate confirmed the receptor to be the same 58-kDa protein. Western blot analysis with anti-Hsp60 MAb of whole-cell adhesion between Caco-2 and WT also revealed the receptor protein to be a 58-kDa protein, thus corroborating the identification of Hsp60 as a host cell receptor for LAP. Furthermore, the anti-Hsp60 antibody also caused approximately 74% reduction in binding of L. monocytogenes WT to Caco-2 cells, whereas a control antibody, C11E9, had no effect on binding. The adhesion mechanism of L. monocytogenes to eukaryotic cells is a complex process, and identification of Hsp60 as a receptor for LAP adds to the list of previously discovered ligand-receptor modules that are essential to achieve successful adhesion. PMID:14742538

  17. Heat Shock Gene Expression Is Controlled Primarily at the Translational Level in Carrot Cells and Somatic Embryos.

    PubMed Central

    Apuya, NR; Zimmerman, JL

    1992-01-01

    We have determined that the synthesis of heat shock proteins is regulated ultimately at the translational level in heat-shocked carrot callus cells and somatic embryos. Polysome analysis revealed that heat-shocked callus cells do not translate most heat shock transcripts, which they abundantly synthesize and accumulate. By contrast, heat-shocked globular embryos accumulate low levels of heat shock mRNA but selectively translate more of the heat shock mRNA molecules compared to callus cells and embryos of later stages. The overall result of these different translational control schemes is that undifferentiated callus cells and globular embryos synthesize comparable levels of heat shock proteins even though they have large differences in heat shock transcript levels. PMID:12297657

  18. Involvement of heat shock protein 47 in Schistosoma japonicum-induced hepatic fibrosis in mice.

    PubMed

    Huang, Jia-Quan; Tao, Ran; Li, Lan; Ma, Ke; Xu, Lei; Ai, Guo; Fan, Xiang-Xue; Jiao, Yun-Tao; Ning, Qin

    2014-01-01

    Chronic infection with the blood fluke Schistosoma japonicum is associated with both liver cirrhosis and liver cancer. Previously, heat shock protein 47, a collagen-specific molecular chaperone, was shown to play a critical role in the maturation of procollagen. However, less is known about the role of heat shock protein 47 in S. japonicum-induced hepatic fibrosis. We therefore investigated the expression of heat shock protein 47 in S. japonicum-induced liver fibrosis and attempted to determine whether inhibition of heat shock protein 47 could have beneficial effects on fibrosis in vitro and in vivo. In this study, we found that the expression of heat shock protein 47 was significantly increased in patients with Schistosoma-induced fibrosis, as well as in rodent models. Immunohistochemistry revealed heat shock protein 47-positive cells were found in the periphery of egg granulomas. Administration of heat shock protein 47-targeted short hairpin (sh)RNA remarkably reduced heat shock protein 47 expression and collagen deposition in NIH3T3 cells and liver tissue of S. japonicum-infected mice. Life-table analysis revealed a dose-dependent prolongation of survival rates with the treatment of heat shock protein 47-shRNA in murine fibrosis models. Moreover, serum alanine aminotransferase and aspartate transaminase activity, splenomegaly, spleen weight index and portal hypertension were also measured, which showed improvement with the anti-fibrosis treatment. The fibrosis-related parameters assessed were expressions of Col1a1, Col3a1, TGF-β1, CTGF, IL-13, IL-17, MMP-9, TIMP-1 and PAI-1 in the liver. This study demonstrated that heat shock protein 47-targeted shRNA directly reduced collagen production of mouse liver fibrosis associated with S. japonicum. We conclude that heat shock protein 47 plays an essential role in S. japonicum-induced hepatic fibrosis in mice and may be a potential target for ameliorating the hepatic fibrosis caused by this parasite. PMID:24295791

  19. α-Crystallin-Type Heat Shock Proteins: Socializing Minichaperones in the Context of a Multichaperone Network

    PubMed Central

    Narberhaus, Franz

    2002-01-01

    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. PMID:11875128

  20. Phylogenetic analysis of the Trypanosoma genus based on the heat-shock protein 70 gene.

    PubMed

    Fraga, Jorge; Fernández-Calienes, Aymé; Montalvo, Ana Margarita; Maes, Ilse; Deborggraeve, Stijn; Büscher, Philippe; Dujardin, Jean-Claude; Van der Auwera, Gert

    2016-09-01

    Trypanosome evolution was so far essentially studied on the basis of phylogenetic analyses of small subunit ribosomal RNA (SSU-rRNA) and glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) genes. We used for the first time the 70kDa heat-shock protein gene (hsp70) to investigate the phylogenetic relationships among 11 Trypanosoma species on the basis of 1380 nucleotides from 76 sequences corresponding to 65 strains. We also constructed a phylogeny based on combined datasets of SSU-rDNA, gGAPDH and hsp70 sequences. The obtained clusters can be correlated with the sections and subgenus classifications of mammal-infecting trypanosomes except for Trypanosoma theileri and Trypanosoma rangeli. Our analysis supports the classification of Trypanosoma species into clades rather than in sections and subgenera, some of which being polyphyletic. Nine clades were recognized: Trypanosoma carassi, Trypanosoma congolense, Trypanosoma cruzi, Trypanosoma grayi, Trypanosoma lewisi, T. rangeli, T. theileri, Trypanosoma vivax and Trypanozoon. These results are consistent with existing knowledge of the genus' phylogeny. Within the T. cruzi clade, three groups of T. cruzi discrete typing units could be clearly distinguished, corresponding to TcI, TcIII, and TcII+V+VI, while support for TcIV was lacking. Phylogenetic analyses based on hsp70 demonstrated that this molecular marker can be applied for discriminating most of the Trypanosoma species and clades. PMID:27180897

  1. Nucleopolyhedroviruses (NPV) induce the expression of small heat shock protein 25.4 in Antheraea pernyi.

    PubMed

    Zhang, Congfen; Zhu, Baojian; Dai, Li Shang; Liu, Chaoliang; Luo, Xuegang

    2016-10-15

    Nucleopolyhedroviruses (NPVs) is one group of Baculoviruses. The infection of NPV in silkworm is often lethal. To investigate the effective measures to stop the infection of NPV, we cloned cDNA encoding small heat shock protein 25.4 in Antheraea pernyi (Ap-HSP25.4). The translated amino acid sequence consisted of 223 residues with a calculated molecular mass of 25.4kDa and an isoelectronic point (pI) of 4.93. Quantitative real-time PCR was used to investigate the expression patterns and distribution profiles of Ap-sHSP25.4 before and after challenged with NPV. We found that the inhibitors of eicosanoid synthesis could suppress the transcription of Ap-sHSP25.4 in the fat body in a dose dependent manner. And arachidonic acid induced the expression of Ap-sHSP25.4. Thus, we concluded that sHSPs may be promising candidates to boost insect immunity in practice. PMID:27265031

  2. Characterization and Expression of Genes Encoding Three Small Heat Shock Proteins in Sesamia inferens (Lepidoptera: Noctuidae)

    PubMed Central

    Sun, Meng; Lu, Ming-Xing; Tang, Xiao-Tian; Du, Yu-Zhou

    2014-01-01

    The pink stem borer, Sesamia inferens (Walker), is a major pest of rice and is endemic in China and other parts of Asia. Small heat shock proteins (sHSPs) encompass a diverse, widespread class of stress proteins that have not been characterized in S. inferens. In the present study, we isolated and characterized three S. inferens genes that encode members of the α-crystallin/sHSP family, namely, Sihsp21.4, Sihsp20.6, and Sihsp19.6. The three cDNAs encoded proteins of 187, 183 and 174 amino acids with calculated molecular weights of 21.4, 20.6 and 19.6 kDa, respectively. The deduced amino acid sequences of the three genes showed strong similarity to sHSPs identified in other lepidopteran insects. Sihsp21.4 contained an intron, but Sihsp20.6 and Sihsp19.6 lacked introns. Real-time quantitative PCR analyses revealed that Sihsp21.4 was most strongly expressed in S. inferens heads; Whereas expression of Sihsp20.6 and Sihsp19.6 was highest in eggs. The three S. inferens sHSP genes were up-regulated during low temperature stress. In summary, our results show that S. inferens sHSP genes have distinct regulatory roles in the physiology of S. inferens. PMID:25514417

  3. Large changes in intracellular pH and calcium observed during heat shock are not responsible for the induction of heat shock proteins in Drosophila melanogaster.

    PubMed Central

    Drummond, I A; McClure, S A; Poenie, M; Tsien, R Y; Steinhardt, R A

    1986-01-01

    Heat shock caused significant changes in intracellular pH (pHi) and intracellular free calcium concentration [( Ca2+]i) which occurred rapidly after temperature elevation. pHi fell from a resting level value at 25 degrees C of 7.38 +/- 0.02 (mean +/- standard error of the mean, n = 15) to 6.91 +/- 0.11 (n = 7) at 35 degrees C. The resting level value of [Ca2+]i in single Drosophila melanogaster larval salivary gland cells was 198 +/- 31 nM (n = 4). It increased approximately 10-fold, to 1,870 +/- 770 nM (n = 4), during a heat shock. When salivary glands were incubated in calcium-free, ethylene glycol-bis(beta-aminoethyl ether)-N,N',N'-tetraacetic acid (EGTA)-buffered medium, the resting level value of [Ca2+]i was reduced to 80 +/- 7 nM (n = 3), and heat shock resulted in a fourfold increase in [Ca2+]i to 353 +/- 90 nM (n = 3). The intracellular free-ion concentrations of Na+, K+, Cl-, and Mg2+ were 9.6 +/- 0.8, 101.9 +/- 1.7, 36 +/- 1.5, and 2.4 +/- 0.2 mM, respectively, and remained essentially unchanged during a heat shock. Procedures were devised to mimic or block the effects of heat shock on pHi and [Ca2+]i and to assess their role in the induction of heat shock proteins. We report here that the changes in [Ca2+]i and pHi which occur during heat shock are not sufficient, nor are they required, for a complete induction of the heat shock response. Images PMID:3097504

  4. DYNAMICS OF A SPHERICAL ACCRETION SHOCK WITH NEUTRINO HEATING AND ALPHA-PARTICLE RECOMBINATION

    SciTech Connect

    Fernandez, Rodrigo; Thompson, Christopher

    2009-10-01

    We investigate the effects of neutrino heating and alpha-particle recombination on the hydrodynamics of core-collapse supernovae. Our focus is on the nonlinear dynamics of the shock wave that forms in the collapse and the assembly of positive energy material below it. To this end, we perform time-dependent hydrodynamic simulations with FLASH2.5 in spherical and axial symmetry. These generalize our previous calculations by allowing for bulk neutrino heating and for nuclear statistical equilibrium between n, p, and alpha. The heating rate is freely tunable, as is the starting radius of the shock relative to the recombination radius of alpha-particles. An explosion in spherical symmetry involves the excitation of an overstable mode, which may be viewed as the l = 0 version of the 'Standing Accretion Shock Instability'. In two-dimensional simulations, nonspherical deformations of the shock are driven by plumes of material with positive Bernoulli parameter, which are concentrated well outside the zone of strong neutrino heating. The nonspherical modes of the shock reach a large amplitude only when the heating rate is also high enough to excite convection below the shock. The critical heating rate that causes an explosion depends sensitively on the initial position of the shock relative to the recombination radius. Weaker heating is required to drive an explosion in two dimensions than in one, but the difference also depends on the size of the shock. Forcing the infalling heavy nuclei to break up into n and p below the shock only causes a slight increase in the critical heating rate, except when the shock starts out at a large radius. This shows that heating by neutrinos (or some other mechanism) must play a significant role in pushing the shock far enough out that recombination heating takes over.

  5. Heat Shock Protein 90 regulates encystation in Entamoeba

    PubMed Central

    Singh, Meetali; Sharma, Shalini; Bhattacharya, Alok; Tatu, Utpal

    2015-01-01

    Enteric protozoan Entamoeba histolytica is a major cause of debilitating diarrheal infection worldwide with high morbidity and mortality. Even though the clinical burden of this parasite is very high, this infection is categorized as a neglected disease. Parasite is transmitted through feco-oral route and exhibit two distinct stages namely – trophozoites and cysts. Mechanism and regulation of encystation is not clearly understood. Previous studies have established the role of Heat shock protein 90 (Hsp90) in regulating stage transition in various protozoan parasites like Giardia, Plasmodium, Leishmania, and Toxoplasma. Our study for the first time reports that Hsp90 plays a crucial role in life cycle of Entamoeba as well. We identify Hsp90 to be a negative regulator of encystation in Entamoeba. We also show that Hsp90 inhibition interferes with the process of phagocytosis in Entamoeba. Overall, we show that Hsp90 plays an important role in virulence and transmission of Entamoeba. PMID:26528271

  6. Immunity to heat shock proteins and arthritic disorders.

    PubMed Central

    van Eden, W

    1999-01-01

    Adjuvant arthritis (AA) is a frequently used model of experimental arthritis. Because of its histopathology, which is reminiscent of rheumatoid arthritis in humans, AA is used as a model for the development of novel anti-inflammatory drugs. Recently, it has become evident that AA is a typical T-cell-mediated autoimmune condition. Therefore, novel immunotherapies targeted to T cells can be developed in this model. Analysis of responding T cells in AA have now led to the definition of various antigens with potential relevance to arthritis, including human arthritic conditions. One such antigen defined in AA is the 60kD heat shock protein. Both T-cell vaccination approaches and active antigen immunizations and antigen toleration approaches have turned out to be effective in suppressing AA. PMID:10231009

  7. Proteomic Analysis of Trypanosoma cruzi Epimastigotes Subjected to Heat Shock

    PubMed Central

    Pérez-Morales, Deyanira; Lanz-Mendoza, Humberto; Hurtado, Gerardo; Martínez-Espinosa, Rodrigo; Espinoza, Bertha

    2012-01-01

    Trypanosoma cruzi is exposed to sudden temperature changes during its life cycle. Adaptation to these variations is crucial for parasite survival, reproduction, and transmission. Some of these conditions may change the pattern of genetic expression of proteins involved in homeostasis in the course of stress treatment. In the present study, the proteome of T. cruzi epimastigotes subjected to heat shock and epimastigotes grow normally was compared by two-dimensional gel electrophoresis followed by mass spectrometry for protein identification. Twenty-four spots differing in abundance were identified. Of the twenty-four changed spots, nineteen showed a greater intensity and five a lower intensity relative to the control. Several functional categories of the identified proteins were determined: metabolism, cell defense, hypothetical proteins, protein fate, protein synthesis, cellular transport, and cell cycle. Proteins involved in the interaction with the cellular environment were also identified, and the implications of these changes are discussed. PMID:22287837

  8. Heat Shock Protein 70: Roles in Multiple Sclerosis

    PubMed Central

    Mansilla, María José; Montalban, Xavier; Espejo, Carmen

    2012-01-01

    Heat shock proteins (HSP) have long been considered intracellular chaperones that possess housekeeping and cytoprotective functions. Consequently, HSP overexpression was proposed as a potential therapy for neurodegenerative diseases characterized by the accumulation or aggregation of abnormal proteins. Recently, the discovery that cells release HSP with the capacity to trigger proinflammatory as well as immunoregulatory responses has focused attention on investigating the role of HSP in chronic inflammatory autoimmune diseases such as multiple sclerosis (MS). To date, the most relevant HSP is the inducible Hsp70, which exhibits both cytoprotectant and immunoregulatory functions. Several studies have presented contradictory evidence concerning the involvement of Hsp70 in MS or experimental autoimmune encephalomyelitis (EAE), the MS animal model. In this review, we dissect the functions of Hsp70 and discuss the controversial data concerning the role of Hsp70 in MS and EAE. PMID:22669475

  9. Heat Shock Proteins Promote Cancer: It's a Protection Racket.

    PubMed

    Calderwood, Stuart K; Gong, Jianlin

    2016-04-01

    Heat shock proteins (HSP) are expressed at high levels in cancer and form a fostering environment that is essential for tumor development. Here, we review the recent data in this area, concentrating mainly on Hsp27, Hsp70, and Hsp90. The overriding role of HSPs in cancer is to stabilize the active functions of overexpressed and mutated cancer genes. Thus, elevated HSPs are required for many of the traits that underlie the morbidity of cancer, including increased growth, survival, and formation of secondary cancers. In addition, HSPs participate in the evolution of cancer treatment resistance. HSPs are also released from cancer cells and influence malignant properties by receptor-mediated signaling. Current data strongly support efforts to target HSPs in cancer treatment. PMID:26874923

  10. Heat shock proteins: possible biomarkers in pulmonary and extrapulmonary tuberculosis.

    PubMed

    Shekhawat, Seema D; Jain, Ruchika K; Gaherwar, Hari M; Purohit, Hemant J; Taori, Girdhar M; Daginawala, Hatim F; Kashyap, Rajpal S

    2014-02-01

    Tuberculosis (TB) and Tuberculous meningitis (TBM) caused by Mycobacterium tuberculosis (MTB) continue to be a major cause of morbidity and mortality. Therefore there is a need to explore potential biomarkers and heat shock proteins [Hsp(s)] could be one such candidate. We found that host (Hsp 25, Hsp 60, Hsp 70 and Hsp 90) and MTB Hsp(s) (Hsp 16, Hsp 65 and Hsp 71) to be an important feature of the immune response in human clinical samples of pulmonary and extrapulmonary TB patients and in MTB infected monocytes. Notably, the host (Hsp 25, Hsp 70 and Hsp 90) and MTB (Hsp 16, Hsp 65 and Hsp 71) Hsp(s) increases significantly in the clinical samples as well as in cell line model after TB infection. Collectively, results revealed that alteration in immune response leads to a change in the both host and MTB Hsp profile, highlighting them as possible biomarkers for the disease. PMID:24269695

  11. Modification of tooth development by heat shock protein 60.

    PubMed

    Papp, Tamas; Polyak, Angela; Papp, Krisztina; Meszar, Zoltan; Zakany, Roza; Meszar-Katona, Eva; Tünde, Palne Terdik; Ham, Chang Hwa; Felszeghy, Szabolcs

    2016-01-01

    Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes. PMID:27025262

  12. Modification of tooth development by heat shock protein 60

    PubMed Central

    Papp, Tamas; Polyak, Angela; Papp, Krisztina; Meszar, Zoltan; Zakany, Roza; Meszar-Katona, Eva; Tünde, Palne Terdik; Ham, Chang Hwa; Felszeghy, Szabolcs

    2016-01-01

    Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes. PMID:27025262

  13. SPERM MOTILITY IN HSF1 KNOCKOUT MICE AFTER HEAT SHOCK IS ASSOCIATED WITH FERTILITY DEFICITS

    EPA Science Inventory

    SPERM MOTILITY IN HSF1 KNOCKOUT MICE AFTER HEAT SHOCK IS ASSOCIATED WITH FERTILITY DEFICITS. L.F. Strader*, S.D. Perreault, J.C. Luft*, and D.J. Dix*. US EPA/ORD, Reproductive Toxicology Div., Research Triangle Park, NC
    Heat shock proteins (HSPs) protect cells from environm...

  14. Effects of several factors on the heat-shock-induced thermotolerance of Listeria monocytogenes.

    PubMed Central

    Pagán, R; Condón, S; Sala, F J

    1997-01-01

    The influence of the temperature at which Listeria monocytogenes had been grown (4 or 37 degrees C) on the response to heat shocks of different durations at different temperatures was investigated. For cells grown at 4 degrees C, the effect of storage, prior to and after heat shock, on the induced thermotolerance was also studied. Death kinetics of heat-shocked cells is also discussed. For L. monocytogenes grown at 37 degrees C, the greatest response to heat shock was a fourfold increase in thermotolerance. For L. monocytogenes grown at 4 degrees C, the greatest response to heat shock was a sevenfold increase in thermotolerance. The only survival curves of cells to have shoulders were those for cells that had been heat shocked. A 3% concentration of sodium chloride added to the recovery medium made these shoulders disappear and decreased decimal reduction times. The percentage of cells for which thermotolerance increased after a heat shock was smaller the milder the heat shock and the longer the prior storage. PMID:9251209

  15. Similarity flow in interaction of a shock wave with an inclined heated channel

    SciTech Connect

    Artemiev, V.I.; Medvedyuk, S.A.; Rybakov, V.A.

    1993-11-01

    A study is made of gasdynamic flow that initiates when a shock wave propagates along a thin heated channel. Analytical conditions of the onset of an unsteady flow precursor are obtained. The flow similarity is proved experimentally; precursor characteristics vs shock wave and heated channel parameters are analyzed.

  16. Synthesis of the low molecular weight heat shock proteins in plants

    SciTech Connect

    Mansfield, M.A.; Key, J.L. )

    1987-08-01

    Heat shock of living tissue induces the synthesis of a unique group of proteins, the heat shock proteins. In plants, the major group of heat shock proteins has a molecular mass of 15 to 25 kilodaltons. Accumulation to these proteins to stainable levels has been reported in only a few species. To examine accumulation of the low molecular weight heat shock proteins in a broader range of species, two-dimensional electrophoresis was used to resolve total protein from the following species: soybean (Glycine max L. Merr., var Wayne), pea (Pisum sativum L., var Early Alaska), sunflower (Helianthus annuus L.), wheat (Triticum asetivum L.), rice (Oryza sativa L., cv IR-36), maize (Zea mays L.), pearl millet (Pennisetum americanum L. Leeke, line 23DB), and Panicum miliaceum L. When identified by both silver staining and incorporation of radiolabel, a diverse array of low molecular weight heat shock proteins was synthesized in each of these species. These proteins accumulated to significant levels after three hours of heat shock but exhibited considerable heterogeneity in isoelectric point, molecular weight, stainability, and radiolabel incorporation. Although most appeared to be synthesized only during heat shock, some were detectable at low levels in control tissue. Compared to the monocots, a higher proportion of low molecular weight heat shock proteins was detectable in control tissues from dicots.

  17. Expression of Selected Ginkgo biloba Heat Shock Protein Genes After Cold Treatment Could Be Induced by Other Abiotic Stress

    PubMed Central

    Cao, Fuliang; Cheng, Hua; Cheng, Shuiyuan; Li, Linling; Xu, Feng; Yu, Wanwen; Yuan, Honghui

    2012-01-01

    Heat shock proteins (HSPs) play various stress-protective roles in plants. In this study, three HSP genes were isolated from a suppression subtractive hybridization (SSH) cDNA library of Ginkgo biloba leaves treated with cold stress. Based on the molecular weight, the three genes were designated GbHSP16.8, GbHSP17 and GbHSP70. The full length of the three genes were predicted to encode three polypeptide chains containing 149 amino acids (Aa), 152 Aa, and 657 Aa, and their corresponding molecular weights were predicted as follows: 16.67 kDa, 17.39 kDa, and 71.81 kDa respectively. The three genes exhibited distinctive expression patterns in different organs or development stages. GbHSP16.8 and GbHSP70 showed high expression levels in leaves and a low level in gynoecia, GbHSP17 showed a higher transcription in stamens and lower level in fruit. This result indicates that GbHSP16.8 and GbHSP70 may play important roles in Ginkgo leaf development and photosynthesis, and GbHSP17 may play a positive role in pollen maturation. All three GbHSPs were up-regulated under cold stress, whereas extreme heat stress only caused up-regulation of GbHSP70, UV-B treatment resulted in up-regulation of GbHSP16.8 and GbHSP17, wounding treatment resulted in up-regulation of GbHSP16.8 and GbHSP70, and abscisic acid (ABA) treatment caused up-regulation of GbHSP70 primarily. PMID:22754330

  18. Identification of sequence similarity between 60 kDa and 70 kDa molecular chaperones: evidence for a common evolutionary background?

    PubMed Central

    Flores, A I; Cuezva, J M

    1997-01-01

    Recent findings support the premise that chaperonins (60 kDa stress-proteins) and alpha-subunits of F-type ATPases (alpha-ATPase) are evolutionary related protein families. Two-dimensional gel patterns of synthesized proteins in unstressed and heat-shocked embryonic Drosophila melanogaster SL2 cells revealed that antibodies raised against the alpha-subunit of the F1-ATPase complex from rat liver recognize an inducible p71 member of the 70 kDa stress-responsive protein family. Molecular recognition of this stress-responsive 70 kDa protein by antibodies raised against the F1-ATPase alpha-subunit suggests the possibility of partial sequence similarity within these ATP-binding protein families. A multiple sequence alignment between alpha-ATPases and 60 kDa and 70 kDa molecular chaperones is presented. Statistical evaluation of sequence similarity reveals a significant degree of sequence conservation within the three protein families. The finding suggests a common evolutionary origin for the ATPases and molecular chaperone protein families of 60 kDa and 70 kDa, despite the lack of obvious structural resemblance between them. PMID:9065788

  19. Report on the VIIth International Symposium on Heat Shock Proteins in Biology & Medicine.

    PubMed

    Calderwood, Stuart K; Hightower, Lawrence E

    2015-03-01

    This seventh symposium in a series on heat shock proteins in biology and medicine was held November 1-5, 2014, at the Hilton Hotel in Old Town Alexandria, Virginia. Approximately 70 participants including principal investigators, postdoctoral fellows, and graduate students were in attendance. The major themes were: new properties of heat shock proteins (HSPs) and heat shock factor (HSF) and role in the etiology of cancer, molecular chaperones in aging, extracellular HSPs in inflammation and immunity, role of heat shock and the heat shock response in immunity and cancer, protein aggregation disorders and HSP expression, and Hsp70 in blood cell differentiation. The next meeting is planned for the fall of 2016 in the same venue. PMID:25542250

  20. Mathematical modeling of the heat-shock response in HeLa cells.

    PubMed

    Scheff, Jeremy D; Stallings, Jonathan D; Reifman, Jaques; Rakesh, Vineet

    2015-07-21

    The heat-shock response is a key factor in diverse stress scenarios, ranging from hyperthermia to protein folding diseases. However, the complex dynamics of this physiological response have eluded mathematical modeling efforts. Although several computational models have attempted to characterize the heat-shock response, they were unable to model its dynamics across diverse experimental datasets. To address this limitation, we mined the literature to obtain a compendium of in vitro hyperthermia experiments investigating the heat-shock response in HeLa cells. We identified mechanisms previously discussed in the experimental literature, such as temperature-dependent transcription, translation, and heat-shock factor (HSF) oligomerization, as well as the role of heat-shock protein mRNA, and constructed an expanded mathematical model to explain the temperature-varying DNA-binding dynamics, the presence of free HSF during homeostasis and the initial phase of the heat-shock response, and heat-shock protein dynamics in the long-term heat-shock response. In addition, our model was able to consistently predict the extent of damage produced by different combinations of exposure temperatures and durations, which were validated against known cellular-response patterns. Our model was also in agreement with experiments showing that the number of HSF molecules in a HeLa cell is roughly 100 times greater than the number of stress-activated heat-shock element sites, further confirming the model's ability to reproduce experimental results not used in model calibration. Finally, a sensitivity analysis revealed that altering the homeostatic concentration of HSF can lead to large changes in the stress response without significantly impacting the homeostatic levels of other model components, making it an attractive target for intervention. Overall, this model represents a step forward in the quantitative understanding of the dynamics of the heat-shock response. PMID:26200855

  1. Heat-shock protein 60 kDa and atherogenic dyslipidemia in patients with untreated mild periodontitis: a pilot study.

    PubMed

    Rizzo, Manfredi; Cappello, Francesco; Marfil, Rafael; Nibali, Luigi; Marino Gammazza, Antonella; Rappa, Francesca; Bonaventura, Giuseppe; Galindo-Moreno, Pablo; O'Valle, Francisco; Zummo, Giovanni; Conway de Macario, Everly; Macario, Alberto J L; Mesa, Francisco

    2012-05-01

    Identification of predictors of cardiovascular risk can help in the prevention of pathologic episodes and the management of patients at all stages of illness. Here, we investigated the relationships between serum levels of Hsp60 and dyslipidemia in patients with periodontitis by performing a cross-sectional study of 22 patients with mild periodontitis without any prior treatment for it (i.e., drug naïve) and 22 healthy controls, matched for age and body mass index (BMI). All subjects were evaluated for periodontal status, gingival inflammation, and oral hygiene. Levels of circulating Hsp60, C-reactive protein (CRP), and plasma lipids were measured, and small, dense low-density lipoproteins (LDL) were indirectly assessed by determining the triglycerides/high-density lipoproteins (HDL) cholesterol ratio. We also assessed by immunohistochemistry Hsp60 levels in oral mucosa of patients and controls. No difference was found in CRP levels or plasma lipids between the two groups, but subjects with periodontitis showed, in comparison to controls, higher levels of small, dense LDL (p  = 0.0355) and circulating Hsp60 concentrations (p < 0.0001). However, levels of mucosal Hsp60 did not change significantly between groups. Correlation analysis revealed that circulating Hsp60 inversely correlated with HDL-cholesterol (r  = -0.589, p  = 0.0039), and positively with triglycerides (r  = +0.877, p < 0.0001), and small, dense LDL (r  = +0.925, p < 0.0001). Serum Hsp60 significantly correlated with the degree of periodontal disease (r  = +0.403, p  = 0.0434). In brief, untreated patients with mild periodontitis had increased small, dense LDL and serum Hsp60 concentrations, in comparison to age- and BMI-matched controls and both parameters showed a strong positive correlation. Our data indicate that atherogenic dyslipidemia and elevated circulating Hsp60 tend to be linked and associated to periodontal pathology. Thus, the road is open to investigate the potential value of elevated levels of circulating Hsp60 as predictor of risk for cardiovascular disease when associated to dyslipidemia in periodontitis patients. PMID:22215516

  2. Interaction between the inducible 70-kDa heat shock protein and autophagy: effects on fertility and pregnancy.

    PubMed

    Sisti, Giovanni; Kanninen, Tomi T; Ramer, Ilana; Witkin, Steven S

    2015-09-01

    A consequence of hsp70 (HSPA1A) induction is the inhibition of autophagy. Evidence of autophagy involvement in all aspects of the reproductive process is reviewed, and possible consequences of hsp70 induction at each developmental stage are postulated. It is proposed that aberrant external or internal stimuli that result in high levels of hsp70 production interfere with normal autophagy-related functions and lead to a decrease in the number of functional ova and spermatozoa, impaired pre- and post-implantation embryo development, and increased susceptibility to premature labor and delivery. The purpose of this review is to increase understanding of hsp70-autophagy interactions during reproduction. Interventions to modulate this interaction will lead to development of novel protocols to improve fertility and pregnancy outcome. PMID:26081752

  3. Heat induction of heat shock protein 25 requires cellular glutamine in intestinal epithelial cells.

    PubMed

    Phanvijhitsiri, Kittiporn; Musch, Mark W; Ropeleski, Mark J; Chang, Eugene B

    2006-08-01

    Glutamine is considered a nonessential amino acid; however, it becomes conditionally essential during critical illness when consumption exceeds production. Glutamine may modulate the heat shock/stress response, an important adaptive cellular response for survival. Glutamine increases heat induction of heat shock protein (Hsp) 25 in both intestinal epithelial cells (IEC-18) and mesenchymal NIH/3T3 cells, an effect that is neither glucose nor serum dependent. Neither arginine, histidine, proline, leucine, asparagine, nor tyrosine acts as physiological substitutes for glutamine for heat induction of Hsp25. The lack of effect of these amino acids was not caused by deficient transport, although some amino acids, including glutamate (a major direct metabolite of glutamine), were transported poorly by IEC-18 cells. Glutamate uptake could be augmented in a concentration- and time-dependent manner by increasing either media concentration and/or duration of exposure. Under these conditions, glutamate promoted heat induction of Hsp25, albeit not as efficiently as glutamine. Further evidence for the role of glutamine conversion to glutamate was obtained with the glutaminase inhibitor 6-diazo-5-oxo-l-norleucine (DON), which inhibited the effect of glutamine on heat-induced Hsp25. DON inhibited phosphate-dependent glutaminase by 75% after 3 h, decreasing cell glutamate. Increased glutamine/glutamate conversion to glutathione was not involved, since the glutathione synthesis inhibitor, buthionine sulfoximine, did not block glutamine's effect on heat induction of Hsp25. A large drop in ATP levels did not appear to account for the diminished Hsp25 induction during glutamine deficiency. In summary, glutamine is an important amino acid, and its requirement for heat-induced Hsp25 supports a role for glutamine supplementation to optimize cellular responses to pathophysiological stress. PMID:16554407

  4. HEAT SHOCK PROTEINS IN DIABETES AND WOUND HEALING

    PubMed Central

    Atalay, Mustafa; Oksala, Niku; Lappalainen, Jani; Laaksonen, David E.; Sen, Chandan K.; Roy, Sashwati

    2009-01-01

    The heat shock proteins (HSPs), originally identified as heat-inducible gene products, are a highly conserved family of proteins that respond to a wide variety of stress. Although HSPs are among the most abundant intracellular proteins, they are expressed at low levels under normal physiological conditions, and show marked induction in response to various stressors. HSPs function primarily as molecular chaperones, facilitating the folding of other cellular proteins, preventing protein aggregation, or targeting improperly folded proteins to specific pathways for degradation. By modulating inflammation, wound debris clearance, cell proliferation, migration and collagen synthesis, HSPs are essential for normal wound healing of the skin. In this review, our goal is to discuss the role and clinical implications of HSP with respect to skin wound healing and diabetes. The numerous defects in the function of HSPs associated with diabetes could contribute to the commonly observed complications and delayed wound healing in diabetics. Several physical, pharmacological and genetic approaches may be considered to address HSP-directed therapies both in the laboratory and in the clinics. PMID:19275675

  5. Heat shock proteins: molecular chaperones of protein biogenesis.

    PubMed Central

    Craig, E A; Gambill, B D; Nelson, R J

    1993-01-01

    Heat shock proteins (Hsps) were first identified as proteins whose synthesis was enhanced by stresses such as an increase in temperature. Recently, several of the major Hsps have been shown to be intimately involved in protein biogenesis through a direct interaction with a wide variety of proteins. As a reflection of this role, these Hsps have been referred to as molecular chaperones. Hsp70s interact with incompletely folded proteins, such as nascent chains on ribosomes and proteins in the process of translocation from the cytosol into mitochondria and the endoplasmic reticulum. Hsp60 also binds to unfolded proteins, preventing aggregation and facilitating protein folding. Although less well defined, other Hsps such as Hsp90 also play important roles in modulating the activity of a number of proteins. The function of the proteolytic system is intertwined with that of molecular chaperones. Several components of this system, encoded by heat-inducible genes, are responsible for the degradation of abnormal or misfolded proteins. The budding yeast Saccharomyces cerevisiae has proven very useful in the analysis of the role of molecular chaperones in protein maturation, translocation, and degradation. In this review, results of experiments are discussed within the context of experiments with other organisms in an attempt to describe the current state of understanding of these ubiquitous and important proteins. PMID:8336673

  6. Electron heating by ion acoustic turbulence in simulated low Mach number shocks

    NASA Technical Reports Server (NTRS)

    Tokar, Robert L.; Gary, S. Peter; Quest, Kevin B.

    1987-01-01

    Explicit and fully electromagnetic particle-in-cell simulations of perpendicular, collisionless, and nominally subcritical shocks are performed in one and two spatial dimensions using the code wave. Shock parameters are chosen to maximixe the growth rates of the current-driven ion acoustic instability in the shock. Electron heating by ion acoustic turbulence is observed at the shocks, at rates in agreement with second-order Vlasov theory predictions. However, the amount of resistive electron heating is small and ion reflection provides the major source of dissipation. Strictly resistive shocks do not exist for the parameters suitable for explicit particle codes running on today's supercomputers, because the plasma convects through these shocks so quickly that current-driven instabilities have little time to be amplified and to heat the electrons resistively. This effect is primarily a result of the relatively small values of omega(pe)/omega(ce) that can be analyzed.

  7. Heating a plasma by a broadband stream of fast electrons: Fast ignition, shock ignition, and Gbar shock wave applications

    SciTech Connect

    Gus’kov, S. Yu.; Nicolai, Ph.; Ribeyre, X.; Tikhonchuk, V. T.

    2015-09-15

    An exact analytic solution is found for the steady-state distribution function of fast electrons with an arbitrary initial spectrum irradiating a planar low-Z plasma with an arbitrary density distribution. The solution is applied to study the heating of a material by fast electrons of different spectra such as a monoenergetic spectrum, a step-like distribution in a given energy range, and a Maxwellian spectrum, which is inherent in laser-produced fast electrons. The heating of shock- and fast-ignited precompressed inertial confinement fusion (ICF) targets as well as the heating of a target designed to generate a Gbar shock wave for equation of state (EOS) experiments by laser-produced fast electrons with a Maxwellian spectrum is investigated. A relation is established between the energies of two groups of Maxwellian fast electrons, which are responsible for generation of a shock wave and heating the upstream material (preheating). The minimum energy of the fast and shock igniting beams as well as of the beam for a Gbar shock wave generation increases with the spectral width of the electron distribution.

  8. Developmentally dictated expression of heat shock factors: exclusive expression of HSF4 in the postnatal lens and its specific interaction with alphaB-crystallin heat shock promoter.

    PubMed

    Somasundaram, T; Bhat, Suraj P

    2004-10-22

    The molecular cascade of stress response in higher eukaryotes commences in the cytoplasm with the trimerization of the heat shock factor 1 (HSF1), followed by its transport to the nucleus, where it binds to the heat shock element leading to the activation of transcription from the down-stream gene(s). This well-established paradigm has been mostly studied in cultured cells. The developmental and tissue-specific control of the heat shock transcription factors (HSFs) and their interactions with heat shock promoters remain unexplored. We report here that in the rat lens, among the three mammalian HSFs, expression of HSF1 and HSF2 is largely fetal, whereas the expression of HSF4 is predominantly postnatal. Similar pattern of expression of HSF1 and HSF4 is seen in fetal and adult human lenses. This stage-specific inverse relationship between the expression of HSF1/2 and HSF4 suggests tissue-specific management of stress depending on the presence or absence of specific HSF(s). In addition to real-time PCR and immunoblotting, gel mobility shift assays, coupled with specific antibodies and HSE probes, derived from three different heat shock promoters, establish that there is no HSF1 or HSF2 binding activity in the postnatal lens nuclear extracts. Using this unique, developmentally modulated in vivo system, we demonstrate 1) specific patterns of HSF4 binding to heat shock elements derived from alphaB-crystallin, Hsp70, and Hsp82 promoters and 2) that it is HSF4 and not HSF1 or HSF2 that interacts with the canonical heat shock element of the alphaB-crystallin gene. PMID:15308659

  9. Induction of heat shock proteins in B-cell exosomes.

    PubMed

    Clayton, Aled; Turkes, Attilla; Navabi, Hossein; Mason, Malcolm D; Tabi, Zsuzsanna

    2005-08-15

    Exosomes are nanometer-sized vesicles secreted by a diverse range of live cells that probably have physiological roles in modulating cellular immunity. The extracellular factors that regulate the quantity and phenotype of exosomes produced are poorly understood, and the properties of exosomes that dictate their immune functions are not yet clear. We investigated the effect of cellular stress on the exosomes produced by B-lymphoblastoid cell lines. Under steady-state conditions, the exosomes were positive for hsp27, hsc70, hsp70 and hsp90, and other recognised exosome markers such as MHC class I, CD81, and LAMP-2. Exposing cells to heat stress (42 degrees C for up to 3 hours), resulted in a marked increase in these heat shock proteins (hsps), while the expression of other stress proteins such as hsp60 and gp96 remained negative, and other exosome markers remained unchanged. Stress also triggered a small increase in the quantity of exosomes produced [with a ratio of 1.245+/-0.07 to 1 (mean+/-s.e.m., n=20) of 3-hour-stress-exosomes to control-exosomes]. Flow-cytometric analysis of exosome-coated beads and immuno-precipitation of intact exosomes demonstrated that hsps were located within the exosome lumen, and not present at the exosome-surface, suggesting that such exosomes may not interact with target cells through cell-surface hsp-receptors. Functional studies further supported this finding, in that exosomes from control or heat-stressed B cells did not trigger dendritic cell maturation, assessed by analysis of dendritic-cell-surface phenotype, and cytokine secretion profile. Our findings demonstrate that specific alterations in exosome phenotype are a hitherto unknown component of the cellular response to environmental stress and their extracellular function does not involve the direct activation of dendritic cells. PMID:16046478

  10. Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor

    SciTech Connect

    Kroes, R.A. Northwestern Univ., Evanston, IL ); Abravaya, K.; Morimoto, R.I. ); Seidenfeld, J. )

    1991-06-01

    Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on expression of the c-fos, c-myc, or {beta}-actin genes. The active component of BCNU and related compounds appears to be the isocyanate moiety that causes carbamoylation of proteins and nucleic acids. Transcriptional activation of the human HSP70 gene by BCNU is dependent on the heat shock element and correlates with the level of heat shock transcription factor and its binding to the heat shock element in vivo. Unlike activation by heat or heavy metals, BCNU-mediated activation is strongly dependent upon new protein synthesis. This suggests that BCNU-induced, isocyanate-mediated damage to newly synthesized protein(s) may be responsible for activation of the heat shock transcription factor and increased transcription of the HSP90 and HSP70 genes.

  11. The Membrane-Associated Transient Receptor Potential Vanilloid Channel Is the Central Heat Shock Receptor Controlling the Cellular Heat Shock Response in Epithelial Cells

    PubMed Central

    Bromberg, Zohar; Goloubinoff, Pierre; Saidi, Younousse; Weiss, Yoram George

    2013-01-01

    The heat shock response (HSR) is a highly conserved molecular response to various types of stresses, including heat shock, during which heat-shock proteins (Hsps) are produced to prevent and repair damages in labile proteins and membranes. In cells, protein unfolding in the cytoplasm is thought to directly enable the activation of the heat shock factor 1 (HSF-1), however, recent work supports the activation of the HSR via an increase in the fluidity of specific membrane domains, leading to activation of heat-shock genes. Our findings support the existence of a plasma membrane-dependent mechanism of HSF-1 activation in animal cells, which is initiated by a membrane-associated transient receptor potential vanilloid receptor (TRPV). We found in various non-cancerous and cancerous mammalian epithelial cells that the TRPV1 agonists, capsaicin and resiniferatoxin (RTX), upregulated the accumulation of Hsp70, Hsp90 and Hsp27 and Hsp70 and Hsp90 respectively, while the TRPV1 antagonists, capsazepine and AMG-9810, attenuated the accumulation of Hsp70, Hsp90 and Hsp27 and Hsp70, Hsp90, respectively. Capsaicin was also shown to activate HSF-1. These findings suggest that heat-sensing and signaling in mammalian cells is dependent on TRPV channels in the plasma membrane. Thus, TRPV channels may be important drug targets to inhibit or restore the cellular stress response in diseases with defective cellular proteins, such as cancer, inflammation and aging. PMID:23468922

  12. Effects of feed restriction on the upper temperature tolerance and heat shock response in juvenile green and white sturgeon.

    PubMed

    Lee, Seunghyung; Hung, Silas S O; Fangue, Nann A; Haller, Liran; Verhille, Christine E; Zhao, Juan; Todgham, Anne E

    2016-08-01

    The objective of the current study was to investigate the effects of feed restriction on whole-organism upper thermal tolerance and the heat shock response of green and white sturgeon to determine how changes in food amount might influence physiological performance of each species when faced with temperature stress. Two parallel feed restriction trials were carried out for juvenile green (202g; 222-day post hatch: dph) and white sturgeon (205g; 197-dph) to manipulate nutritional status at 12.5%, 25%, 50%, or 100% of optimum feeding rate (100% OFR were 1.6% and 1.8% body weight/day, respectively) for four weeks. Following the trials, the critical thermal maximum (CTMax, 0.3°C/min) of sturgeon (N=12/treatment/species) was assessed as an indicator of whole-organism upper thermal tolerance. To assess temperature sensitivity, sturgeon (N=9/treatment/species) were acutely transferred to two temperature treatments (28°C and 18°C as a handling control) for 2h followed by 2h of recovery at 18°C before being sacrificed, and gill, brain, and mucus sampled for measurements of 70-kDa heat shock protein levels (Hsc/Hsp70). Feeding rate had species-specific effects on CTMax in green and white sturgeon such that CTMax of green sturgeon decreased as the magnitude of feed restriction increased; whereas, CTMax of white sturgeon did not change with feed restriction. Elevated temperature (28°C) and feed restriction increased Hsc/Hsp70 levels in the gill tissue of green sturgeon, while heat shock increased Hsc/Hsp70 levels in the mucus of white sturgeon. Our results suggest that green sturgeon may be more susceptible to temperature stress under food-limited conditions. PMID:27095630

  13. Expression profile of heat shock response factors during hookworm larval activation and parasitic development.

    PubMed

    Gelmedin, Verena; Delaney, Angela; Jennelle, Lucas; Hawdon, John M

    2015-07-01

    When organisms are exposed to an increase in temperature, they undergo a heat shock response (HSR) regulated by the transcription factor heat shock factor 1 (HSF-1). The heat shock response includes the rapid changes in gene expression initiated by binding of HSF-1 to response elements in the promoters of heat shock genes. Heat shock proteins function as molecular chaperones to protect proteins during periods of elevated temperature and other stress. During infection, hookworm infective third stage larvae (L3) undergo a temperature shift from ambient to host temperature. This increased temperature is required for the resumption of feeding and activation of L3, but whether this increase initiates a heat shock response is unknown. To investigate the role of the heat shock in hookworm L3 activation and parasitic development, we identified and characterized the expression profile of several components of the heat shock response in the hookworm Ancylostoma caninum. We cloned DNAs encoding an hsp70 family member (Aca-hsp-1) and an hsp90 family member (Aca-daf-21). Exposure to a heat shock of 42°C for one hour caused significant up-regulation of both genes, which slowly returned to near baseline levels following one hour attenuation at 22°C. Neither gene was up-regulated in response to host temperature (37°C). Conversely, levels of hsf-1 remained unchanged during heat shock, but increased in response to incubation at 37°C. During activation, both hsp-1 and daf-21 are down regulated early, although daf-21 levels increase significantly in non-activated control larvae after 12h, and slightly in activated larvae by 24h incubation. The heat shock response modulators celastrol and KNK437 were tested for their effects on gene expression during heat shock and activation. Pre-incubation with celastrol, an HSP90 inhibitor that promotes heat shock gene expression, slightly up-regulated expression of both hsp-1 and daf-21 during heat shock. KNK437, an inhibitor of heat shock

  14. Cellular response to heat shock studied by multiconfocal fluorescence correlation spectroscopy.

    PubMed

    Kloster-Landsberg, Meike; Herbomel, Gaëtan; Wang, Irène; Derouard, Jacques; Vourc'h, Claire; Usson, Yves; Souchier, Catherine; Delon, Antoine

    2012-09-19

    Heat shock triggers a transient and ubiquitous response, the function of which is to protect cells against stress-induced damage. The heat-shock response is controlled by a key transcription factor known as heat shock factor 1 (HSF1). We have developed a multiconfocal fluorescence correlation spectroscopy setup to measure the dynamics of HSF1 during the course of the heat-shock response. The system combines a spatial light modulator, to address several points of interest, and an electron-multiplying charge-coupled camera for fast multiconfocal recording of the photon streams. Autocorrelation curves with a temporal resolution of 14 μs were analyzed before and after heat shock on eGFP and HSF1-eGFP-expressing cells. Evaluation of the dynamic parameters of a diffusion-and-binding model showed a slower HSF1 diffusion after heat shock. It is also observed that the dissociation rate decreases after heat shock, whereas the association rate is not affected. In addition, thanks to the multiconfocal fluorescence correlation spectroscopy system, up to five spots could be simultaneously located in each cell nucleus. This made it possible to quantify the intracellular variability of the diffusion constant of HSF1, which is higher than that of inert eGFP molecules and increases after heat shock. This finding is consistent with the fact that heat-shock response is associated with an increase of HSF1 interactions with DNA and cannot be explained even partially by heat-induced modifications of nuclear organization. PMID:22995483

  15. Modeling and effects of nonlocal electron heat flow in planar shock waves

    SciTech Connect

    Vidal, F.; Matte, J.P.; Casanova, M.; Larroche, O.

    1995-05-01

    Electron heat flow was computed in the context of a steadily propagating shock wave. Two problems were studied: a Mach 8 shock in hydrogen, simulated with an ion kinetic code, and a Mach 5 shock in lithium, simulated with an Eulerian hydrodynamic code. The electron heat flow was calculated with Spitzer--Haerm classical conductivity, with and without a flux limit, and several nonlocal electron heat flow formulas published in the literature. To evaluate these, the shock`s density, velocity, and ion temperature profiles were fixed, and the electron temperature and heat flow were compared to those computed by an electron kinetic code. There were quantitative differences between the electron temperature profiles calculated with the various formulas. For the Mach 8 shock in hydrogen, the best agreement with the kinetic simulation was obtained with the Epperlein--Short delocalization formula [Phys. Fluids B {bold 4}, 2211 and 4190 (1992)], and the Luciani--Mora--Bendib formula [Phys. Rev. Lett. {bold 55}, 2421 (1985)] gave good agreement. For the Mach 5 shock in lithium, both of these gave good agreement. The earlier Luciani--Mora--Virmont formula [Phys. Rev. Lett. {bold 51}, 1664 (1983)] gave fair agreement, while that of San Martin {ital et} {ital al}. [Phys. Fluids B {bold 4}, 3579 (1992); {bold 5}, 1485 (1993)] was even further off than the classical Spitzer--Haerm [Phys. Rev. {bold 89}, 977 (1953)] formula for thermal conduction. To assess the effect of nonlocal electron heat flow on the shock`s hydrodynamics and ion kinetics, each of the two problems was done with two different electron heat flow models: the classical Spitzer--Haerm local heat conductivity, and the Epperlein--Short nonlocal electron heat-flow formula. In spite of the somewhat different electron temperature profiles, the effect on the shock dynamics was not important. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  16. Escape of heated ions upstream of quasi-parallel shocks

    NASA Technical Reports Server (NTRS)

    Edmiston, J. P.; Kennel, C. F.; Eichler, D.

    1982-01-01

    A simple theoretical criterion by which quasi-parallel and quasi-perpendicular collisionless shocks may be distinguished is proposed on the basis of an investigation of the free escape of ions from the post-shock plasma into the region upstream of a fast collisionless shock. It was determined that the accessibility of downstream ions to the upstream region depends on upstream magnetic field shock normal angle, in addition to the upstream plasma parameters, with post-shock ions escaping upstream for shock normal angles of less than 45 deg, in agreement with the observed transition between quasi-parallel and quasi-perpendicular shock structure. Upstream ion distribution functions resembling those of observed intermediate ions and beams are also calculated.

  17. Exercise-induced ROS in heat shock proteins response.

    PubMed

    Dimauro, Ivan; Mercatelli, Neri; Caporossi, Daniela

    2016-09-01

    Cells have evolved multiple and sophisticated stress response mechanisms aiming to prevent macromolecular (including proteins, lipids, and nucleic acids) damage and to maintain or re-establish cellular homeostasis. Heat shock proteins (HSPs) are among the most highly conserved, ubiquitous, and abundant proteins in all organisms. Originally discovered more than 50 years ago through heat shock stress, they display multiple, remarkable roles inside and outside cells under a variety of stresses, including also oxidative stress and radiation, recognizing unfolded or misfolded proteins and facilitating their restructuring. Exercise consists in a combination of physiological stresses, such as metabolic disturbances, changes in circulating levels of hormones, increased temperature, induction of mild to severe inflammatory state, increased production of reactive oxygen and nitrogen species (ROS and RNS). As a consequence, exercise is one of the main stimuli associated with a robust increase in different HSPs in several tissues, which appears to be also fundamental in facilitating the cellular remodeling processes related to the training regime. Among all factors involved in the exercise-related modulation of HSPs level, the ROS production in the contracting muscle or in other tissues represents one of the most attracting, but still under discussion, mechanism. Following exhaustive or damaging muscle exercise, major oxidative damage to proteins and lipids is likely involved in HSP expression, together with mechanically induced damage to muscle proteins and the inflammatory response occurring several days into the recovery period. Instead, the transient and reversible oxidation of proteins by physiological concentrations of ROS seems to be involved in the activation of stress response following non-damaging muscle exercise. This review aims to provide a critical update on the role of HSPs response in exercise-induced adaptation or damage in humans, focusing on experimental

  18. Plasma heating at collisionless shocks due to the kinetic cross-field streaming instability

    NASA Technical Reports Server (NTRS)

    Winske, D.; Quest, K. B.; Tanaka, M.; Wu, C. S.

    1985-01-01

    Heating at collisionless shocks due to the kinetic cross-field streaming instability, which is the finite beta (ratio of plasma to magnetic pressure) extension of the modified two stream instability, is studied. Heating rates are derived from quasi-linear theory and compared with results from particle simulations to show that electron heating relative to ion heating and heating parallel to the magnetic field relative to perpendicular heating for both the electrons and ions increase with beta. The simulations suggest that electron dynamics determine the saturation level of the instability, which is manifested by the formation of a flattop electron distribution parallel to the magnetic field. As a result, both the saturation levels of the fluctuations and the heating rates decrease sharply with beta. Applications of these results to plasma heating in simulations of shocks and the earth's bow shock are described.

  19. The identification of a heat-shock protein complex in chloroplasts of barley leaves.

    PubMed

    Clarke, A K; Critchley, C

    1992-12-01

    In vivo radiolabeling of chloroplast proteins in barley (Hordeum vulgare L. cv Corvette) leaves and their separation by one-dimensional electrophoresis revealed at least seven heat-shock proteins between 24 and 94 kD, of which most have not been previously identified in this C(3) species. Fractionation into stromal and thylakoid membrane components showed that all chloroplast heat-shock proteins were synthesized on cytoplasmic ribosomes, translocated into the chloroplast, and located in the stroma. Examination of stromal preparations by native (nondissociating) polyacrylamide gel electrophoresis revealed the presence of a high-molecular mass heat-shock protein complex in barley. This complex was estimated to be 250 to 265 kD in size. Dissociation by denaturing polyacrylamide gel electrophoresis revealed a single protein component, a 32-kD heat-shock protein. The synthesis of this protein and the formation of the heat-shock protein complex were dependent on functional cytoplasmic ribosomes. Immunological studies showed that the heat-shock protein complex did not contain any proteins homologous to the alpha-subunit of ribulose bisphosphate carboxylase oxygenase subunit-binding protein. Other features about the complex included the absence of nucleic acid (RNA or DNA) and its nondissociation in the presence of Mg(2+)/ATP. These results suggest that the heat-shock protein complex in barley chloroplasts is a homogeneous octamer of 32-kD subunits. PMID:16653243

  20. The Identification of a Heat-Shock Protein Complex in Chloroplasts of Barley Leaves 1

    PubMed Central

    Clarke, Adrian K.; Critchley, Christa

    1992-01-01

    In vivo radiolabeling of chloroplast proteins in barley (Hordeum vulgare L. cv Corvette) leaves and their separation by one-dimensional electrophoresis revealed at least seven heat-shock proteins between 24 and 94 kD, of which most have not been previously identified in this C3 species. Fractionation into stromal and thylakoid membrane components showed that all chloroplast heat-shock proteins were synthesized on cytoplasmic ribosomes, translocated into the chloroplast, and located in the stroma. Examination of stromal preparations by native (nondissociating) polyacrylamide gel electrophoresis revealed the presence of a high-molecular mass heat-shock protein complex in barley. This complex was estimated to be 250 to 265 kD in size. Dissociation by denaturing polyacrylamide gel electrophoresis revealed a single protein component, a 32-kD heat-shock protein. The synthesis of this protein and the formation of the heat-shock protein complex were dependent on functional cytoplasmic ribosomes. Immunological studies showed that the heat-shock protein complex did not contain any proteins homologous to the α-subunit of ribulose bisphosphate carboxylase oxygenase subunit-binding protein. Other features about the complex included the absence of nucleic acid (RNA or DNA) and its nondissociation in the presence of Mg2+/ATP. These results suggest that the heat-shock protein complex in barley chloroplasts is a homogeneous octamer of 32-kD subunits. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:16653243

  1. Heat-shock protein-25/27 phosphorylation by the delta isoform of protein kinase C.

    PubMed Central

    Maizels, E T; Peters, C A; Kline, M; Cutler, R E; Shanmugam, M; Hunzicker-Dunn, M

    1998-01-01

    Small heat-shock proteins (sHSPs) are widely expressed 25-28 kDa proteins whose functions are dynamically regulated by phosphorylation. While recent efforts have clearly delineated a stress-responsive p38 mitogen-activated protein-kinase (MAPK)-dependent kinase pathway culminating in activation of the heat-shock (HSP)-kinases, mitogen-activated protein-kinase-activated protein kinase-2 and -3, not all sHSP phosphorylation events can be explained by the p38 MAPK-dependent pathway. The contribution of protein kinase C (PKC) to sHSP phosphorylation was suggested by early studies but later questioned on the basis of the reported poor ability of purified PKC to phosphorylate sHSP in vitro. The current study re-evaluates the role of PKC in sHSP phosphorylation in the light of the isoform complexity of the PKC family. We evaluated the sHSP phosphorylation status in rat corpora lutea obtained from two stages of pregnancy, mid-pregnancy and late-pregnancy, which express different levels of the novel PKC isoform, PKC-delta. Two-dimensional Western blot analysis showed that HSP-27 was more highly phosphorylated in vivo in corpora lutea of late pregnancy, corresponding to the developmental stage in which PKC-delta is abundant and active. Late-pregnant luteal extracts contained a lipid-sensitive HSP-kinase activity which exactly co-purified with PKC-delta using hydroxyapatite and S-Sepharose column chromatography. To determine whether there might be preferential phosphorylation of sHSP by a particular PKC isoform, purified recombinant PKC isoforms corresponding to those PKC isoforms detected in rat corpora lutea were evaluated for HSP-kinase activity in vitro. Recombinant PKC-delta effectively catalysed the phosphorylation of sHSP in vitro, and PKC-alpha was 30-50% as effective as an HSP-kinase; other PKCs tested (beta1, beta2, epsilon and zeta) were poor HSP-kinases. These results show that select PKC family members can function as direct HSP-kinases in vitro. Moreover, the

  2. Heat-shock-induced cellular responses to temperature elevations occurring during orthopaedic cutting.

    PubMed

    Dolan, E B; Haugh, M G; Tallon, D; Casey, C; McNamara, L M

    2012-12-01

    Severe heat-shock to bone cells caused during orthopaedic procedures can result in thermal damage, leading to cell death and initiating bone resorption. By contrast, mild heat-shock has been proposed to induce bone regeneration. In this study, bone cells are exposed to heat-shock for short durations occurring during surgical cutting. Cellular viability, necrosis and apoptosis are investigated immediately after heat-shock and following recovery of 12, 24 h and 4 days, in osteocyte-like MLO-Y4 and osteoblast-like MC3T3-E1 cells, using flow cytometry. The regeneration capacity of heat-shocked Balb/c mesenchymal stem cells (MSCs) and MC3T3-E1s has been investigated following 7 and 14 day's recovery, by quantifying proliferation, differentiation and mineralization. An immediate necrotic response to heat-shock was shown in cells exposed to elevated temperatures (45°C, 47°C and most severe at 60°C). A longer-term apoptotic response is induced in MLO-Y4s and, to a lesser extent, in MC3T3-E1s. Heat-shock-induced differentiation and mineralization by MSCs. These findings indicate that heat-shock is more likely to induce apoptosis in osteocytes than osteoblasts, which might reflect their role as sensors detecting and communicating damage within bone. Furthermore, it is shown for the first time that mild heat-shock (less than equal to 47°C) for durations occurring during surgical cutting can positively enhance osseointegration by osteoprogenitors. PMID:22915633

  3. Shock

    MedlinePlus

    ... Emergencies A-Z Share this! Home » Emergency 101 Shock Shock is a serious, often life-threatening medical condition ... of death for critically ill or injured people. Shock results when the body is not getting enough ...

  4. Shock

    MedlinePlus

    ... problems) Hypovolemic shock (caused by too little blood volume) Anaphylactic shock (caused by allergic reaction) Septic shock ( ... as heart attack or heart failure ) Low blood volume (as with heavy bleeding or dehydration ) Changes in ...

  5. Heat Shock Proteins in Dermatophytes: Current Advances and Perspectives.

    PubMed

    Martinez-Rossi, Nilce M; Jacob, Tiago R; Sanches, Pablo R; Peres, Nalu T A; Lang, Elza A S; Martins, Maíra P; Rossi, Antonio

    2016-04-01

    Heat shock proteins (HSPs) are proteins whose transcription responds rapidly to temperature shifts. They constitute a family of molecular chaperones, involved in the proper folding and stabilisation of proteins under physiological and adverse conditions. HSPs also assist in the protection and recovery of cells exposed to a variety of stressful conditions, including heat. The role of HSPs extends beyond chaperoning proteins, as they also participate in diverse cellular functions, such as the assembly of macromolecular complexes, protein transport and sorting, dissociation of denatured protein aggregates, cell cycle control, and programmed cell death. They are also important antigens from a variety of pathogens, are able to stimulate innate immune cells, and are implicated in acquired immunity. In fungi, HSPs have been implicated in virulence, dimorphic transition, and drug resistance. Some HSPs are potential targets for therapeutic strategies. In this review, we discuss the current understanding of HSPs in dermatophytes, which are a group of keratinophilic fungi responsible for superficial mycoses in humans and animals. Computational analyses were performed to characterise the group of proteins in these dermatophytes, as well as to assess their conservation and to identify DNA-binding domains (5'-nGAAn-3') in the promoter regions of the hsp genes. In addition, the quantification of the transcript levels of few genes in a pacC background helped in the development of an extended model for the regulation of the expression of the hsp genes, which supports the participation of the pH-responsive transcriptional regulator PacC in this process. PMID:27226766

  6. Responses to heat shock, arsenite and cadmium in soybean

    SciTech Connect

    Edelman, L. ); Key, J.L. )

    1989-04-01

    Heat shock (HS), arsenite (As) and cadmium (Cd) treatments induced the HS response in soybean seedlings but differed in their abilities to induce stress tolerance. Pretreatment of seedlings with sub-lethal HS protected them from subsequent normally lethal HS treatment. However, the protection was much more pronounced in 1 day-old than in 2 day-old plants. Sublethal arsenite pretreatment resulted in only a low level of protection against lethal As or HS treatment and severe damage still occurred in specific tissues. Cadmium did not induce any self- or cross-protection. DNA sequence analyses revealed that HS, As and Cd induced the transcription of similar sequences. However, Northern blot analyses of HS mRNAs, and analyses of in vitro translation products and in vivo-labeled proteins by 1D and 2D SDS-PAGE demonstrated that, compared to HS, the response to the chemical stresses was slower, less intense and not as selective. Apparently any causal relationship between HS proteins and induced stress tolerance must also involve developmental-, tissue-, and/or quantitative-specificities.

  7. Urease-associated heat shock protein of Helicobacter pylori.

    PubMed Central

    Evans, D J; Evans, D G; Engstrand, L; Graham, D Y

    1992-01-01

    Helicobacter pylori urease is an extracellular, cell-bound enzyme with a molecular weight of approximately 600,000 (600K enzyme) comprising six 66K and six 31K subunits. A 62K protein is closely associated with the H. pylori urease, both in crude preparations and after gel filtration; this protein can be removed from the urease by ion-exchange chromatography without inactivating the enzyme. We purified this urease-associated protein and determined its N-terminal amino acid sequence. The sequence is 80% homologous (identical plus conserved amino acid residues) to the Escherichia coli GroEL heat shock protein (HSP), 75% homologous to the human homolog, and 84% homologous to the HSP homolog found in species of Chlamydia. Thus, the 62K urease-associated protein of H. pylori belongs to the HSP60 family of stress proteins known as chaperonins. Evidently this protein, HSP62, participates in the extracellular assembly and/or protection of the urease against inactivation in the hostile environment of the stomach. Images PMID:1348725

  8. EXTRACELLULAR HEAT SHOCK PROTEINS: A NEW LOCATION, A NEW FUNCTION

    PubMed Central

    De Maio, Antonio; Vazquez, Daniel

    2015-01-01

    The expression of heat shock proteins (hsp) is a basic and well conserved cellular response to an array of stresses. These proteins are involved in the repair of cellular damage induced by the stress, which is necessary for the salutary resolution from the insult. Moreover, they confer protection from subsequent insults, which has been coined stress tolerance. Since these proteins are expressed in subcellular compartments, it was thought that their function during stress conditions was circumscribed to the intracellular environment. However, it is now well established that hsp can also be present outside cells where they appear to display a function different than the well understood chaperone role. Extracellular hsp act as alert stress signals priming other cells, particularly of the immune system, to avoid the propagation of the insult and favor resolution. Since the majority of hsp do not possess a secretory peptide signal, they are likely be exported by a non-classical secretory pathway. Different mechanisms have been proposed to explain the export of hsp, including translocation across the plasma membrane and release associated with lipid vesicles, as well as the passive release after cell death by necrosis. Extracellular hsp appear in various flavors, including membrane-bound and membrane-free forms. All of these variants of extracellular hsp suggest that their interactions with cells may be quite diverse, both in target cell types and the activation signaling pathways. This review addresses some of our current knowledge about the release and relevance of extracellular hsp. PMID:23807250

  9. Heat Shock Factor 1 Mediates Latent HIV Reactivation

    PubMed Central

    Pan, Xiao-Yan; Zhao, Wei; Zeng, Xiao-Yun; Lin, Jian; Li, Min-Min; Shen, Xin-Tian; Liu, Shu-Wen

    2016-01-01

    HSF1, a conserved heat shock factor, has emerged as a key regulator of mammalian transcription in response to cellular metabolic status and stress. To our knowledge, it is not known whether HSF1 regulates viral transcription, particularly HIV-1 and its latent form. Here we reveal that HSF1 extensively participates in HIV transcription and is critical for HIV latent reactivation. Mode of action studies demonstrated that HSF1 binds to the HIV 5′-LTR to reactivate viral transcription and recruits a family of closely related multi-subunit complexes, including p300 and p-TEFb. And HSF1 recruits p300 for self-acetylation is also a committed step. The knockout of HSF1 impaired HIV transcription, whereas the conditional over-expression of HSF1 improved that. These findings demonstrate that HSF1 positively regulates the transcription of latent HIV, suggesting that it might be an important target for different therapeutic strategies aimed at a cure for HIV/AIDS. PMID:27189267

  10. Facets of heat shock protein 70 show immunotherapeutic potential

    PubMed Central

    Todryk, Stephen M; Gough, Michael J; Pockley, A Graham

    2003-01-01

    Amongst the families of intracellular molecules that chaperone and assist with the trafficking of other proteins, notably during conditions of cellular stress, heat shock protein (hsp) 70 is one of the most studied. Although its name suggests that expression is exclusively induced during cellular hyperthermia, members of the hsp70 family of proteins can be constitutively expressed and/or induced by a range of other cellular insults. The ubiquitous presence of hsp70 in eukaryotic and prokaryotic cells, combined with its high degree of sequence homology and intrinsic immunogenicity, have prompted the suggestion that inappropriate immune reactivity to hsp70 might lead to pro-inflammatory responses and the development of autoimmune disease. Indeed, hsp70 has been shown to be a potent activator of innate immunity and aberrant expression of hsp70 in certain organs promotes immunopathology. However, studies also suggest that hsp70 might have immunotherapeutic potential, as hsp70 purified from malignant and virally infected cells can transfer and deliver antigenic peptides to antigen-presenting cells to elicit peptide-specific immunity and, in contrast to its reported pro-inflammatory effects, the administration of recombinant hsp70 can attenuate experimental autoimmune disease. This review focuses on the immunoregulatory capacity of hsp70 and its potential therapeutic value. PMID:12941135

  11. Molecular chaperones and heat shock proteins in atherosclerosis

    PubMed Central

    Xu, Qingbo; Metzler, Bernhard; Jahangiri, Marjan

    2012-01-01

    In response to stress stimuli, mammalian cells activate an ancient signaling pathway leading to the transient expression of heat shock proteins (HSPs). HSPs are a family of proteins serving as molecular chaperones that prevent the formation of nonspecific protein aggregates and assist proteins in the acquisition of their native structures. Physiologically, HSPs play a protective role in the homeostasis of the vessel wall but have an impact on immunoinflammatory processes in pathological conditions involved in the development of atherosclerosis. For instance, some members of HSPs have been shown to have immunoregulatory properties and modification of innate and adaptive response to HSPs, and can protect the vessel wall from the disease. On the other hand, a high degree of sequence homology between microbial and mammalian HSPs, due to evolutionary conservation, carries a risk of misdirected autoimmunity against HSPs expressed on the stressed cells of vascular endothelium. Furthermore, HSPs and anti-HSP antibodies have been shown to elicit production of proinflammatory cytokines. Potential therapeutic use of HSP in prevention of atherosclerosis involves achieving optimal balance between protective and immunogenic effects of HSPs and in the progress of research on vaccination. In this review, we update the progress of studies on HSPs and the integrity of the vessel wall, discuss the mechanism by which HSPs exert their role in the disease development, and highlight the potential clinic translation in the research field. PMID:22058161

  12. Heat-Shock Protein 90-Targeted Nano Anticancer Therapy.

    PubMed

    Rochani, Ankit K; Ravindran Girija, Aswathy; Borah, Ankita; Maekawa, Toru; Sakthi Kumar, D

    2016-04-01

    Suboptimal chemotherapy of anticancer drugs may be attributed to a variety of cellular mechanisms, which synergize to dodge the drug responses. Nearly 2 decades of heat-shock protein 90 (Hsp90)-targeted drug discovery has shown that the mono-therapy with Hsp90 inhibitors seems to be relatively ineffective compared with combination treatment due to several cellular dodging mechanisms. In this article, we have tried to analyze and review the Hsp90 and mammalian target of rapamycin (m-TOR)-mediated drug resistance mechanisms. By using this information we have discussed about the rationale behind use of drug combinations that includes both or any one of these inhibitors for cancer therapy. Currently, biodegradable nano vector (NV)-loaded novel drug delivery systems have shown to resolve the problems of poor bioavailability. NVs of drugs such as paclitaxel, doxorubicin, daunorubicin, and others have been successfully introduced for medicinal use. Hence, looking at the success of NVs, in this article we have also discussed the progress made in the delivery of biodegradable NV-loaded Hsp90 and m-TOR-targeted inhibitors in multiple drug combinations. We have also discussed the possible ways by which the market success of biodegradable NVs can positively impact the clinical trials of anti-Hsp90 and m-TOR combination strategy. PMID:26886301

  13. Involvement of heat shock proteins in gluten-sensitive enteropathy

    PubMed Central

    Sziksz, Erna; Pap, Domonkos; Veres, Gábor; Fekete, Andrea; Tulassay, Tivadar; Vannay, Ádám

    2014-01-01

    Gluten-sensitive enteropathy, also known as coeliac disease (CD), is an autoimmune disorder occurring in genetically susceptible individuals that damages the small intestine and interferes with the absorption of other nutrients. As it is triggered by dietary gluten and related prolamins present in wheat, rye and barley, the accepted treatment for CD is a strict gluten-free diet. However, a complete exclusion of gluten-containing cereals from the diet is often difficult, and new therapeutic strategies are urgently needed. A class of proteins that have already emerged as drug targets for other autoimmune diseases are the heat shock proteins (HSPs), which are highly conserved stress-induced chaperones that protect cells against harmful extracellular factors. HSPs are expressed in several tissues, including the gastrointestinal tract, and their levels are significantly increased under stress circumstances. HSPs exert immunomodulatory effects, and also play a crucial role in the maintenance of epithelial cell structure and function, as they are responsible for adequate protein folding, influence the degradation of proteins and cell repair processes after damage, and modulate cell signalling, cell proliferation and apoptosis. The present review discusses the involvement of HSPs in the pathophysiology of CD. Furthermore, HSPs may represent a useful therapeutic target for the treatment of CD due to the cytoprotective, immunomodulatory, and anti-apoptotic effects in the intestinal mucosal barrier. PMID:24914370

  14. Heat Shock Proteins: Cellular and molecular mechanisms in the CNS

    PubMed Central

    Stetler, R. Anne; Gan, Yu; Zhang, Wenting; Liou, Anthony K.; Gao, Yanqin; Cao, Guodong; Chen, Jun

    2010-01-01

    Emerging evidence describe heat shock proteins (HSPs) as critical regulators in normal neural physiological function as well as in cell stress responses. The functions of HSPs represent an enormous and diverse range of cellular activities, far beyond the originally identified role in protein folding and chaperoning. Now understood to be involved in processes such as synaptic transmission, autophagy, ER stress response, protein kinase and cell death signaling as well as protein chaperone and folding, manipulation of HSPs have robust effects on the fate of cells in neurological injury and disease states. The ongoing exploration of multiple HSP superfamilies has underscored the pluripotent nature of HSPs in the cellular context, and demanded the recent restructuring of the nomenclature referring to these families to reflect a re-organization based on structure and function. In keeping with this re-organization, we have first discussed the HSP superfamilies in terms of protein structure, regulation and expression and distribution in the brain. We then explore major cellular functions of HSPs that are relevant to neural physiological states, and from there discuss known and proposed HSP impact on major neurological disease states. This review article presents a three-part discussion on the array of HSPs families relevant to neuronal tissue, their cellular functions, and the exploration of therapeutic targets of these proteins in the context of neurological diseases. PMID:20685377

  15. A Bipolar Planetary Nebula NGC 6537: Photoionization or Shock Heating?

    NASA Astrophysics Data System (ADS)

    Hyung, Siek

    1999-04-01

    NGC 6537 is an extremely high excitation bipolar planetary nebula. It exhibits a huge range of excitation from lines of [N I] to [Si VI] or [Fe VII], i.e. from neutral atoms to atoms requiring an ionization potential of 167eV. Its kinematical structures are of special interest. We are here primarily concerned with its high resolution spectrum as revealed by the Hamilton Echelle Spectrograph at Lick Observatory (resolution 0.2 A,) and supplemented by UV and near-UV data. Photoionization model reproduces the observed global spectrum of NGC 6537, the absolute H beta flux, and the observed visual or blue magnitude fairly well. The nebulosity of NGC 6537 is likely to be the result of photo-ionization by a very hot star of Teff 180,000 K, although the global nebular morphology and kinematics suggest an effect by strong stellar winds and resulting shock heating. NGC 6537 can be classified as a Peimbert Type I planetary nebula. It is extremely young and it may have originated from a star of about 5 M_sun.

  16. The role of heat shock proteins in gastrointestinal diseases

    PubMed Central

    Dudeja, V; Vickers, S M; Saluja, A K

    2009-01-01

    Heat shock proteins (HSPs) are a highly conserved family of proteins which inhabit almost all subcellular locations and cellular membranes. Depending on their location, these proteins perform a variety of chaperoning functions including folding of newly synthesised polypeptides. HSPs also play a major role in the protection of cells against stressful and injury-inciting stimuli. By virtue of this protective function, HSPs have been shown to prevent acinar cell injury in acute pancreatitis. Also, the levels of HSPs have been shown to be markedly elevated in various forms of cancers when compared with non-transformed cells. Further, inhibition of HSPs has been shown to induce apoptotic cell death in cancer cells suggesting that inhibition of HSPs has a potential to emerge as novel anti-cancer therapy, either as monotherapy or in combination with other chemotherapeutic agents. Several studies have suggested that HSPs can interact with and inhibit both intrinsic and extrinsic pathways of apoptosis at multiple sites. Besides the anti-apoptotic role of HSPs, recent studies suggest that they play a role in the generation of anti-cancer immunity, and attempts have been made to utilise this property of HSPs in the generation of anti-cancer vaccines. The anti-apoptotic function and mechanism of various subtypes of HSPs as well as the current status of anti-HSP therapy are discussed in this review. PMID:19520890

  17. Heat-shock induction of ultraviolet light resistance in Saccharomyces cerevisiae

    SciTech Connect

    Mitchel, R.E.J.; Morrison, D.P.

    1983-10-01

    When exponentially growing diploid wild type Saccharomyces cervisiae cells were subjected to a sudden rise in temperature (heat shock) they responded by increasing their resistance to the lethal effects of ultraviolet light. We have previously reported heat shock-induced increases in heat and ionizing radiation resistance. The shock-induced rise in resistance to uv light reported here was examined in terms of DNA repair capacity, and we find that the increase is due to induction of the recombinational repair system with no significant response from the uv-excision repair process.

  18. Multiple independent regulatory pathways control UBI4 expression after heat shock in Saccharomyces cerevisiae.

    PubMed

    Simon, J R; Treger, J M; McEntee, K

    1999-02-01

    Transcription of the polyubiquitin gene UBI4 of Saccharomyces cerevisiae is strongly induced by a variety of environmental stresses, such as heat shock, nutrient depletion and exposure to DNA-damaging agents. This transcriptional response of UBI4 is likely to be the primary mechanism for increasing the pool of ubiquitin for degradation of stress-damaged proteins. Deletion and promoter fusion studies of the 5' regulatory sequences indicated that two different elements, heat shock elements (HSEs) and stress response element (STREs), contributed independently to heat shock regulation of the UBI4 gene. In the absence of HSEs, STRE sequences localized to the intervals -264 to -238 and -215 to -183 were needed for stress control of transcription after heat shock. Site-directed mutagenesis of the STRE (AG4) at -252 to -248 abolished heat shock induction of UBI4 transcription. Northern analysis demonstrated that cells containing either a temperature-sensitive HSF or non-functional Msn2p/Msn4p transcription factors induced high levels of UBI4 transcripts after heat shock. In cells deficient in both heat stress pathways, heat-induced UBI4 transcript levels were considerably lower but not abolished, suggesting a role for another factor(s) in stress control of its expression. PMID:10048026

  19. Cross-tolerance in the tidepool sculpin: the role of heat shock proteins.

    PubMed

    Todgham, Anne E; Schulte, Patricia M; Iwama, George K

    2005-01-01

    Cross-tolerance, or the ability of one stressor to transiently increase tolerance to a second heterologous stressor, is thought to involve the induction of heat shock proteins (Hsp). We thus investigated the boundaries of cross-tolerance in tidepool sculpins (Oligocottus maculosus) and their relationship to Hsp70 levels. Survival of sculpins exposed to severe osmotic (90 ppt, 2 h) and hypoxic (0.33 mg O(2)/L, 2 h) stressors increased from 68% to 96%, and from 47% to 76%, respectively, following a +12 degrees C heat shock. The magnitude of this heat shock was critical for protection. A +10 degrees C heat shock did not confer cross-tolerance, while a +15 degrees C heat shock was deleterious. Sculpins required between 8 and 48 h of recovery following the +12 degrees C heat shock to develop cross-tolerance. There was no association between Hsp70 levels before the onset of the secondary stressor and cross-tolerance. However, branchial Hsp70 levels following osmotic shock were highly correlated with the time frame of cross-tolerance. Thus, Hsp70 induction by the priming stressor may be less important than the ability of the cell to mount an Hsp response to subsequent stressors. The time frame of cross-tolerance is similar to the interval between low tides, suggesting the possible relevance of this response in nature. PMID:15778933

  20. Role of TRP channels in the induction of heat shock proteins (Hsps) by heating skin

    PubMed Central

    Hsu, Wen-Li; Yoshioka, Tohru

    2015-01-01

    Transient receptor potential (TRP) channels in skin are crucial for achieving temperature sensitivity to maintain internal temperature balance and thermal homeostasis, as well as to protect skin cells from environmental stresses such as infrared (IR) or near-infrared (NIR) radiation via heat shock protein (Hsp) production. However, the mechanisms by which IR and NIR activate TRP channels and produce Hsps intracellularly have been independently reported. In this review, we discuss the relationship between TRP channel activation and Hsp production, and introduce the roles of several skin TRP channels in the regulation of HSP production by IR and NIR exposure. PMID:27493511

  1. Heat shock protein Hsp90-2 expression in the Arabidopsis thaliana seedlings under clinorotation

    NASA Astrophysics Data System (ADS)

    Kozeko, Liudmyla

    Heat shock proteins 90 kDa (Hsp90) are abundant under normal conditions and induced by stress. This family is distinguished from other chaperones in that most of its substrates are signal transduction proteins. Previously, we determined some time-dependent increase in the Hsp90 level in pea seedlings in response to simulated microgravity that indicated a stress-reaction. However, expression of the individual members of the Hsp90 family have specific pattern. The purpose of this study was to investigate possible alterations in the gene expression pattern of cytosolic Hsp90-2 in Arabidopsis thaliana seedlings under 2D-clinorotation. To obtain detailed expression pattern of the HSP90-2 genes we used seeds that provides a resource of loss-of-function mutations gene expression patterns via translational fusions with the reporter gene, GUS (a line N 166718, NASC). There were two variants of the experiment: 1) seedlings grew under clinorotation for 10, 12, 14 d; 2) seedlings grew in the stationary conditions for 10 d followed by clinorotation for 3 h -at 22o C and 16h light cycle. The seedlings grown in the stationary conditions were used as a control. GUS staining showed that HSP90-2 expression was regulated during seedling development and affected by clinorotation in the heterozygous mutant plants. In the homozygous for the mutation plants, HSP90-2 expression was stable during seedling development and not affected by clinorotation. GUS staining was observed in cotyledons, leaves and hypocotyls of the seedlings (especially intense in vascular bundles), indicating intensive cellular processes with participation of this chaperone. Possible pathways of influence of clinorotation on HSP90-2 expression are discussed.

  2. Pharmacologic heat shock protein 70 induction confers cytoprotection against inflammation in gliovascular cells.

    PubMed

    Kacimi, Rachid; Yenari, Midori A

    2015-07-01

    The inhibition of the 90-kDa heat shock protein (HSP90) leads to upregulation of the 70-kDa-inducible HSP70. HSP70 has been previously shown to be neuroprotective and anti-inflammatory. Geldanamycin (GA) and other HSP90 inhibitors have emerged as promising therapeutic agents in cancer, presumably owing to their ability to upregulate HSP70. However, the effects of HSP90 inhibition in brain inflammation are still unclear. We investigate the effect of a panel of HSP90 inhibitors on endotoxin-activated microglia and eventual protection from brain-derived endothelial cells. Prior studies have shown that GA protects brain cells from oxidative stress. We show here that when astrocytes or microglial BV2 cells were pretreated with GA or other HSP90 inhibitors, endotoxin-induced cell death was reduced in cocultures of BV2 microglia and brain-derived endothelial cells (bEND.3). Endotoxin-stimulated BV2 cells led to increased nitric oxide (NO) and inducible nitric oxide synthase which was prevented by treatment with all HSP90 inhibitors. HSP90 inhibitors also prevented lipopolysaccharide (LPS)-induced BV2 cell death. We also found that HSP90 inhibition blocked nuclear translocation of nuclear factor kappa B and attenuated IκBα degradation, and inhibited LPS-activated JAK-STAT phosphorylation. We show that pharmacologic inhibition of HSP90 with subsequent HSP70 induction protects cells that comprise the cerebral vasculature against cell death owing to proinflammatory stimuli. This approach may have therapeutic potential in neurological conditions with an inflammatory component. PMID:25802219

  3. Association of heat shock protein 90 with motility of post-thawed sperm in bulls.

    PubMed

    Zhang, Xiao-Gang; Hu, Shan; Han, Cong; Zhu, Qing-Chao; Yan, Guan-Jie; Hu, Jian-Hong

    2015-04-01

    The correlation between the 90 kDa heat-shock protein (HSP90) and sperm quality following the process of freezing-thawing in bulls has not been studied clearly. Therefore, the objective of the present was to clarify the relationship between HSP90 level and semen parameters during the process of cryopreservation in bulls. Semen samples from 5 Holstein bulls were obtained by artificial vagina. Characteristics of these semen at three stages (fresh, after equilibration and frozen-thawed), including motility, plasma membrane integrity and acrosome integrity were evaluated. The mRNA expression level of HSP90 at the three stages was evaluated by using quantitative Real-Time PCR. Meanwhile, the protein level of HSP90 expression at the three stages was detected according to Western blot. The results showed that sperm parameters evaluated in fresh semen was the highest in the three groups. Sperm parameters in semen after equilibration were lower than those in fresh semen (P>0.05) and higher than those in post-thawed semen (P<0.05). Sperm parameters in frozen-thawed semen were the lowest among the three groups (P<0.05). This study indicated that HSP90 expression is proportional to sperm quality. HSP90 expression level in fresh semen was significantly higher than that in frozen-thawed semen (P<0.05). Although no significant differences in HSP90 expression were observed between fresh semen and semen after equilibration (P>0.05). Results in this study suggest that HSP90 level in bull spermatozoa was gradually declined following the process of freezing-thawing, and might be associated with sperm motility, plasma membrane integrity and acrosome integrity. PMID:25578982

  4. Isolation of a novel inducible rat heat-shock protein (HSP70) gene and its expression during ischaemia/hypoxia and heat shock.

    PubMed Central

    Mestril, R; Chi, S H; Sayen, M R; Dillmann, W H

    1994-01-01

    Most of the members of the mammalian heat-shock protein (HSP) gene family have been studied and isolated from human and mouse cells. Few studies have concentrated on the HSPs of rat, a commonly used experimental animal. We have isolated and characterized a novel inducible rat HSP70 gene using an HSP70 cDNA sequence obtained from an ischaemic rat heart cDNA library. The isolated rat HSP70 gene was found to be a functional gene, as indicated by RNAase-protection and Northern-blot analysis. The deduced amino acid sequence of the inducible rat HSP70 exhibits a high degree of similarity to previously isolated mammalian inducible HSP70 gene products. Expression of the inducible HSP70 gene in rat myogenic cells (H9c2) is markedly increased after relatively short periods of hypoxia as well as by heat shock. Two heat-shock elements (HSE) are present in the rat HSP70 promoter. Transient transfection of rat HSP70 promoter/chloramphenicol acetyltransferase constructs into H9c2 cells shows that the presence of either of the two HSEs is sufficient for heat-shock inducibility. In contrast, induction of the rat HSP70/chloramphenicol acetyltransferase constructs by hypoxia is only detectable when both HSEs are present. This leads us to conclude that the induction of HSP70 by hypoxia and heat shock occurs through the same regulatory HSEs but the activation of the inducible HSP70 gene by heat shock is several-fold higher than by hypoxia. Images Figure 1 Figure 5 Figure 6 Figure 8 PMID:8141767

  5. A Review of Acquired Thermotolerance, Heat Shock Proteins, and Molecular Chaperones in Archaea: Heat Shock in Archaea

    DOE R&D Accomplishments Database

    Trent, J. D.

    1996-02-09

    Acquired thermotolerance, the associated synthesis of heat-shock proteins (HSPs) under stress conditions, and the role of HSPs as molecular chaperones under normal growth conditions have been studied extensively in eukaryotes and bacteria, whereas research in these areas in archaea is only beginning. All organisms have evolved a variety of strategies for coping with high-temperature stress, and among these strategies is the increased synthesis of HSPs. The facts that both high temperatures and chemical stresses induce the HSPs and that some of the HSPs recognize and bind to unfolded proteins in vitro have led to the theory that the function of HSPs is to prevent protein aggregation in vivo. The facts that some HSPs are abundant under normal growth conditions and that they assist in protein folding in vitro have led to the theory that they assist protein folding in vivo; in this role, they are referred to as molecular chaperones. The limited research on acquired thermotolerance, HSPs, and molecular chaperones in archaea, particularly the hyperthermophilic archaea, suggests that these extremophiles provide a new perspective in these areas of research, both because they are members of a separate phylogenetic domain and because they have evolved to live under extreme conditions.

  6. Heat-shock Treatment-mediated Increase in Transduction by Recombinant Adeno-associated Virus 2 Vectors Is Independent of the Cellular Heat-shock Protein 90*

    PubMed Central

    Zhong, Li; Qing, Keyun; Si, Yue; Chen, Linyuan; Tan, Mengqun; Srivastava, Arun

    2007-01-01

    Recombinant adeno-associated virus 2 (AAV) vectors transduction efficiency varies greatly in different cell types. We have described that a cellular protein, FKBP52, in its phosphorylated form interacts with the D-sequence in the viral inverted terminal repeat, inhibits viral second strand DNA synthesis, and limits transgene expression. Here we investigated the role of cellular heat-shock protein 90 (HSP90) in AAV transduction because FKBP52 forms a complex with HSP90, and because heat-shock treatment augments AAV transduction efficiency. Heat-shock treatment of HeLa cells resulted in tyrosine dephosphorylation of FKBP52, led to stabilization of the FKBP52-HSP90 complex, and resulted in ∼6-fold increase in AAV transduction. However, when HeLa cells were pre-treated with tyrphostin 23, a specific inhibitor of cellular epidermal growth factor receptor tyrosine kinase, which phosphorylates FKBP52 at tyrosine residues, heat-shock treatment resulted in a further 18-fold increase in AAV transduction. HSP90 was shown to be a part of the FKBP52-AAV D-sequence complex, but HSP90 by itself did not bind to the D-sequence. Geldanamycin treatment, which disrupts the HSP90-FKBP52 complex, resulted in >22-fold increase in AAV transduction in heat-shock-treated cells compared with heat shock alone. Deliberate overexpression of the human HSP90 gene resulted in a significant decrease in AAV-mediated transduction in tyrphostin 23-treated cells, whereas down-modulation of HSP90 levels led to a decrease in HSP90-FKBP52-AAV D-sequence complex formation, resulting in a significant increase in AAV transduction following pre-treatment with tyrphostin 23. These studies suggest that the observed increase in AAV transduction efficiency following heat-shock treatment is unlikely to be mediated by HSP90 alone and that increased levels of HSP90, in the absence of heat shock, facilitate binding of FKBP52 to the AAV D-sequence, thereby leading to inhibition of AAV-mediated transgene expression

  7. Nonadiabatic electron heating at high-Mach-number perpendicular shocks

    NASA Technical Reports Server (NTRS)

    Tokar, R. L.; Aldrich, C. H.; Forslund, D. W.; Quest, K. B.

    1986-01-01

    Fully kinetic simulations of high-Mach-number (HMN) perpendicular collisionless shocks are described. It is shown that electron acceleration in the cross-shock electron field can produce downstream electron temperature significantly higher than those expected for adiabatic compression. The momentum space for test electrons at Mach 6 is illustrated.

  8. Aerobic heat shock activates trehalose synthesis in embryos of Artemia franciscana.

    PubMed

    Clegg, J S; Jackson, S A

    1992-05-25

    Encysted embryos (cysts) of the brine shrimp, Artemia franciscana, contain large amounts of trehalose which they use as a major substrate for energy metabolism and biosynthesis for development under aerobic conditions at 25 degrees C. When cysts are placed at 42 degrees C (heat shock) these pathways stop, and the cysts re-synthesize the trehalose that was utilized during the previous incubation at 25 degrees C. Glycogen and glycerol, produced from trehalose at 25 degrees C, appear to be substrates for trehalose synthesis during heat shock. Anoxia prevents trehalose synthesis in cysts undergoing heat shock. These results are consistent with the view that trehalose may play a protective role in cells exposed to heat shock, and other environmental insults, in addition to being a storage form of energy and organic carbon for development. PMID:1592115

  9. Exploring systems affected by the heat shock response in Plasmodium falciparum via protein association networks

    PubMed Central

    Lilburn, Timothy G.; Cai, Hong; Gu, Jianying; Zhou, Zhan; Wang, Yufeng

    2015-01-01

    The heat shock response is a general mechanism by which organisms deal with physical insults such as sudden changes in temperature, osmotic and oxidative stresses, and exposure to toxic substances. Plasmodium falciparum is exposed to drastic temperature changes as a part of its life cycle and maintains an extensive repertoire of heat shock response-related proteins. As these proteins serve to maintain the parasite in the face of anti-malarial drugs as well, better understanding of the heat shock-related systems in the malaria parasite will lead to therapeutic approaches that frustrate these systems, leading to more effective use of anti-malarials. Here we use protein association networks to broaden our understanding of the systems impacted by and/or implicated in the heat shock response. PMID:25539848

  10. A unique intron-containing hsp70 gene induced by heat shock and during sporulation in the aquatic fungus Blastocladiella emersonii.

    PubMed

    Stefani, R M; Gomes, S L

    1995-01-11

    We have isolated and characterized cDNA and genomic DNA clones encoding the 70-kDa heat-shock protein (Hsp70) from the aquatic fungus Blastocladiella emersonii (Be). Nucleotide (nt) sequence analysis predicts an acidic protein containing 650 amino acids, with a calculated molecular mass of 70.8 kDa. The Be hsp70 gene is induced by heat shock (HS), as well as during sporulation of the fungus, and its coding region is interrupted by a single intron. All the evidence seems to indicate that this is the only hsp70 in Be. S1 nuclease protection assays revealed that splicing of the hsp70 intron is highly thermoresistant; at the lethal temperature of 42 degrees C, only 30% of the hsp70 mRNAs have not been processed. A single transcription start point (tsp), localized about 30 nt downstream from a putative TATA box, was determined both during HS and at normal temperatures. The promoter region presented several NGAAN repeats (where N is any nucleotide) characteristic of HS elements, as well as putative binding sites for ATF, Sp1 and two metal-responsive elements. PMID:7828923

  11. Tolerization against atherosclerosis using heat shock protein 60.

    PubMed

    Wick, Cecilia

    2016-03-01

    Atherosclerosis is a chronic inflammatory disease of the artery wall, and both innate and adaptive immunity play important roles in the pathogenesis of this disease. In several experimental and human experiments of early atherosclerotic lesions, it has been shown that the first pathogenic event in atherogenesis is intimal infiltration of T cells at predilection sites. These T cells react to heat shock protein 60 (HSP60), which is a ubiquitous self-antigen expressed on the surface of endothelial cells (ECs) together with adhesion molecules in response to classical risk factors for atherosclerosis. When HSP60 is expressed on the EC surface, it can act as a "danger-signal" for both cellular and humoral immune reactions. Acquired by infection or vaccination, beneficial protective immunity to microbial HSP60 and bona fide autoimmunity to biochemically altered autologous HSP60 is present in all humans. Thus, the development of atherosclerosis during aging is paid by the price for lifelong protective preexisting anti-HSP60 immunity by harmful (auto)immune cross-reactive attack on arterial ECs maltreated by atherosclerosis risk factors. This is supported by experiments, which shows that bacterial HSP60 immunization can lead and accelerate experimental atherosclerosis. This review article presents accumulating proof that supports the idea that tolerization with antigenic HSP60 protein or its peptides may arrest or even prevent atherosclerosis by increased production of regulatory T cells and/or anti-inflammatory cytokines. Recent data indicates that HSP60, or more likely some of its derivative peptides, has immunoregulatory functions. Therefore, these peptides may have important potential for being used as diagnostic agents or therapeutic targets. PMID:26577462

  12. Efficient electron heating in relativistic shocks and gamma-ray-burst afterglow.

    PubMed

    Gedalin, M; Balikhin, M A; Eichler, D

    2008-02-01

    Electrons in shocks are efficiently energized due to the cross-shock potential, which develops because of differential deflection of electrons and ions by the magnetic field in the shock front. The electron energization is necessarily accompanied by scattering and thermalization. The mechanism is efficient in both magnetized and nonmagnetized relativistic electron-ion shocks. It is proposed that the synchrotron emission from the heated electrons in a layer of strongly enhanced magnetic field is responsible for gamma-ray-burst afterglows. PMID:18352129

  13. Heat shock disassembles the nucleolus and inhibits nuclear protein import and poly(A)+ RNA export.

    PubMed Central

    Liu, Y; Liang, S; Tartakoff, A M

    1996-01-01

    Heat shock causes major positive and negative changes in gene expression, drastically alters the appearance of the nucleolus and inhibits rRNA synthesis. We here show that it causes many yeast nucleolar proteins, including the fibrillarin homolog Nop1p, to relocate to the cytoplasm. Relocation depends on several proteins implicated in mRNA transport (Mtrps) and is reversible. Two observations indicate, surprisingly, that disassembly results from a reduction in Ssa protein (Hsp70) levels: (i) selective depletion of Ssa1p leads to disassembly of the nucleolus; (ii) preincubation at 37 degrees C protects the nucleolus against disassembly by heat shock, unless expression of Ssa proteins is specifically inhibited. We observed that heat shock or reduction of Ssa1p levels inhibits protein import into the nucleus and therefore we propose that inhibition of import leads to disassembly of the nucleolus. These observations provide a simple explanation of the effects of heat shock on the anatomy of the nucleolus and rRNA transcription. They also extend understanding of the path of nuclear export. Since a number of nucleoplasmic proteins also relocate upon heat shock, these observations can provide a general mechanism for regulation of gene expression. Relocation of the hnRNP-like protein Mtr13p (= Npl3p, Nop3p), explains the heat shock sensitivity of export of average poly(A)+ RNA. Strikingly, Hsp mRNA export appears not to be affected. Images PMID:8978700

  14. c-myc and c-myb protein degradation: effect of metabolic inhibitors and heat shock.

    PubMed Central

    Lüscher, B; Eisenman, R N

    1988-01-01

    The proteins encoded by both viral and cellular forms of the c-myc oncogene have been previously demonstrated to have exceptionally short in vivo half-lives. In this paper we report a comparative study on the parameters affecting turnover of nuclear oncoproteins c-myc, c-myb, and the rapidly metabolized cytoplasmic enzyme ornithine decarboxylase. The degradation of all three proteins required metabolic energy, did not result in production of cleavage intermediates, and did not involve lysosomes or ubiquitin. A five- to eightfold increase in the half-life of c-myc proteins, and a twofold increase in the half-life of c-myb proteins was detected after heat-shock treatment at 46 degrees C. In contrast, heat shock had no effect on the turnover of ornithine decarboxylase. Heat shock also had the effect of increasing the rate of c-myc protein synthesis twofold, whereas c-myb protein synthesis was decreased nearly fourfold. The increased stability and synthesis of c-myc proteins led to an overall increase in the total level of c-myc proteins in response to heat-shock treatment. Furthermore, treatments which reduced c-myc and c-myb protein turnover, such as heat shock and exposure to inhibitors of metabolic energy production, resulted in reduced detergent solubility of both proteins. The recovery from heat shock, as measured by increased turnover and solubility, was energy dependent and considerably more rapid in thermotolerant cells. Images PMID:3043180

  15. Effects of heat shock on survival, proliferation and differentiation of mouse neural stem cells.

    PubMed

    Omori, Hiroyuki; Otsu, Masahiro; Suzuki, Asami; Nakayama, Takashi; Akama, Kuniko; Watanabe, Masaru; Inoue, Nobuo

    2014-02-01

    Hyperthermia during pregnancy is a significant cause of reproductive problems ranging from abortion to congenital defects of the central nervous system (CNS), including neural tube defects and microcephaly. Neural stem cells (NSCs) can proliferate and differentiate into neurons and glia, playing a key role in the formation of the CNS. Here, we examined the effects of heat shock on homogeneous proliferating NSCs derived from mouse embryonic stem cells. After heat shock at 42 °C for 20 min, the proliferating NSCs continued to proliferate, although subtle changes were observed in gene expression and cell survival and proliferation. In contrast, heat shock at 43 °C caused a variety of responses: the up-regulation of genes encoding heat shock proteins (HSP), induction of apoptosis, temporal inhibition of cell proliferation and retardation of differentiation. Finally, effects of heat shock at 44 °C were severe, with almost all cells disappearing and the remaining cells losing the capacity to proliferate and differentiate. These temperature-dependent effects of heat shock on NSCs may be valuable in elucidating the mechanisms by which hyperthermia during pregnancy causes various reproductive problems. PMID:24316183

  16. Synthesis of Early Heat Shock Proteins in Young Leaves of Barley and Sorghum

    PubMed Central

    Clarke, Adrian K.; Critchley, Christa

    1990-01-01

    The in vivo synthesis of early heat-shock proteins in young leaves of barley (Hordeum vulgare L.) and sorghum (Sorghum bicolor L.) was studied by one- and two-dimensional electrophoresis. Analysis of whole leaf protein patterns demonstrated clearly the enhanced resolution of heat-shock proteins, especially those of low molecular weight, when separated by two-dimensional electrophoresis. Comparison between the two cereals showed that a greater number and diversity of heat-shock proteins were induced in the subtropical C4 (sorghum) species compared to the temperate C3 (barley) species. Fractionation of whole leaf proteins into soluble and membrane fractions showed the majority of heat-shock proteins to be associated with the soluble fraction in both sorghum and barley. However, several low molecular mass (17-24 kilodalton) heat-shock proteins were clearly identified in the membrane fractions, indicating a likely association with thylakoid membranes in vivo during the early stages of a heat-shock response in both species. Images Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 PMID:16667750

  17. Aging results in an unusual expression of Drosophila heat shock proteins

    SciTech Connect

    Fleming, J.E.; Walton, J.K.; Dubitsky, R.; Bensch, K.G. )

    1988-06-01

    The authors used high-resolution two-dimensional polyacrylamide gel electrophoresis to evaluate the effect of aging on the heat shock response in Drosophila melanogaster. Although the aging process is not well understood at the molecular level, recent observations suggest that quantitative changes in gene expression occur as these fruit flies approach senescence. Such genetic alterations are in accord with our present data, which clearly show marked differences in the synthesis of heat shock proteins between young and old fruit flies. In 10-day-old flies, a heat shock of 20 min results in the expression of 14 new proteins as detectable by two-dimensional electrophoresis of ({sup 35}S)methionine-labeled polypeptides, whereas identical treatment of 45-day-old flies leads to the expression of at least 50 new or highly up-regulated proteins. In addition, there is also a concomitant increase in the rate of synthesis of a number of the normal proteins in the older animals. Microdensitometric determinations of the low molecular weight heat shock polypeptides on autoradiographs of five age groups revealed that their maximum expression occurs at 47 days for a population of flies with a mean life span of 33.7 days. Moreover, a heat shock effect similar to that observed in senescent flies occurs in young flies fed canavanine, an arginine analogue, before heat shock.

  18. Heat shock factor 1 induces crystallin-αB to protect against cisplatin nephrotoxicity.

    PubMed

    Lou, Qiang; Hu, Yanzhong; Ma, Yuanfang; Dong, Zheng

    2016-07-01

    Cisplatin, a wildly used chemotherapy drug, induces nephrotoxicity that is characterized by renal tubular cell apoptosis. In response to toxicity, tubular cells can activate cytoprotective mechanisms, such as the heat shock response. However, the role and regulation of the heat shock response in cisplatin-induced nephrotoxicity remain largely unclear. In the present study, we demonstrated the induction of heat shock factor (Hsf)1 and the small heat shock protein crystallin-αB (CryAB) during cisplatin nephrotoxicity in mice. Consistently, cisplatin induced Hsf1 and CryAB in a cultured renal proximal tubular cells (RPTCs). RPTCs underwent apoptosis during cisplatin treatment, which was increased when Hsf1 was knocked down. Transfection or restoration of Hsf1 into Hsf1 knockdown cells suppressed cisplatin-induced apoptosis, further supporting a cytoprotective role of Hsf1 and its associated heat shock response. Moreover, Hsf1 knockdown increased Bax translocation to mitochondria and cytochrome c release into the cytosol. In RPTCs, Hsf1 knockdown led to a specific downregulation of CryAB. Transfection of CryAB into Hsf1 knockdown cells diminished their sensitivity to cisplatin-induced apoptosis, suggesting that CryAB may be a key mediator of the cytoprotective effect of Hsf1. Taken together, these results demonstrate a heat shock response in cisplatin nephrotoxicity that is mediated by Hsf1 and CryAB to protect tubular cells against apoptosis. PMID:27194715

  19. Short communication: lack of breed differences in responses of bovine spermatozoa to heat shock.

    PubMed

    Chandolia, R K; Reinertsen, E M; Hansen, P J

    1999-12-01

    An experiment was conducted to test whether the magnitude of effects of heat shock on spermatozoal function were less for thermotolerant breeds (Brahman and other breeds with Brahman influence) than for breeds that evolved in northern Europe (Angus and Holstein). Frozen spermatozoa were thawed, purified by Percoll gradient centrifugation and incubated at 38.5, 41, or 42 degrees C for 4 h. Sperm motility was then analyzed with a Hamilton Thorn Motility Analyzer. Heat shock reduced the percentage of sperm that were motile, mean track speed, and mean path velocity. There were no significant breed x temperature interactions for these traits. The mean frequency of tail beat tended to be reduced by heat shock in bulls of Brahman-influenced breeds and, to a lesser extent, in Brahman bulls, but it was not affected by heat shock in Angus or Holstein bulls. For no traits were there significant temperature x bull within breed interactions. Overall, results indicate that 1) heat shock reduces motility of bovine spermatozoa and 2) genetic effects are unlikely to be an important determinant of the function of ejaculated sperm following heat shock. PMID:10629808

  20. EFFECTS OF HEAT AND BROMOCHLOROACETIC ACID ON MALE REPRODUCTION IN HEAT SHOCK FACTOR-1 GENE KNOCKOUT MICE

    EPA Science Inventory

    Effects of heat and bromochloroacetic acid on male reproduction in heat shock factor-1 gene knockout mice.
    Luft JC1, IJ Benjamin2, JB Garges1 and DJ Dix1. 1Reproductive Toxicology Division, USEPA, RTP, NC, 27711 and 2Dept of Internal Medicine, Univ.of Texas Southwestern Med C...

  1. Experimental Study of Shock Wave Interference Heating on a Cylindrical Leading Edge. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Wieting, Allan R.

    1987-01-01

    An experimental study of shock wave interference heating on a cylindrical leading edge representative of the cowl of a rectangular hypersonic engine inlet at Mach numbers of 6.3, 6.5, and 8.0 is presented. Stream Reynolds numbers ranged from 0.5 x 106 to 4.9 x 106 per ft. and stream total temperature ranged from 2100 to 3400 R. The model consisted of a 3" dia. cylinder and a shock generation wedge articulated to angles of 10, 12.5, and 15 deg. A fundamental understanding was obtained of the fluid mechanics of shock wave interference induced flow impingement on a cylindrical leading edge and the attendant surface pressure and heat flux distributions. The first detailed heat transfer rate and pressure distributions for two dimensional shock wave interference on a cylinder was provided along with insight into the effects of specific heat variation with temperature on the phenomena. Results show that the flow around a body in hypersonic flow is altered significantly by the shock wave interference pattern that is created by an oblique shock wave from an external source intersecting the bow shock wave produced in front of the body.

  2. Heat shock proteins in relation to heat stress tolerance of creeping bentgrass at different N levels.

    PubMed

    Wang, Kehua; Zhang, Xunzhong; Goatley, Mike; Ervin, Erik

    2014-01-01

    Heat stress is a primary factor causing summer bentgrass decline. Changes in gene expression at the transcriptional and/or translational level are thought to be a fundamental mechanism in plant response to environmental stresses. Heat stress redirects protein synthesis in higher plants and results in stress protein synthesis, particularly heat shock proteins (HSPs). The goal of this work was to analyze the expression pattern of major HSPs in creeping bentgrass (Agrostis stolonifera L.) during different heat stress periods and to study the influence of nitrogen (N) on the HSP expression patterns. A growth chamber study on 'Penn-A4' creeping bentgrass subjected to 38/28°C day/night for 50 days, was conducted with four nitrate rates (no N-0, low N-2.5, medium N-7.5, and high N-12.5 kg N ha-1) applied biweekly. Visual turfgrass quality (TQ), normalized difference vegetation index (NDVI), photochemical efficiency of photosystem II (Fv/Fm), shoot electrolyte leakage (ShEL), and root viability (RV) were monitored, along with the expression pattern of HSPs. There was no difference in measured parameters between treatments until week seven, except TQ at week five. At week seven, grass at medium N had better TQ, NDVI, and Fv/Fm accompanied by lower ShEL and higher RV, suggesting a major role in improved heat tolerance. All the investigated HSPs (HSP101, HSP90, HSP70, and sHSPs) were up-regulated by heat stress. Their expression patterns indicated cooperation between different HSPs and their roles in bentgrass thermotolerance. In addition, their production seems to be resource dependent. This study could further improve our understanding about how different N levels affect bentgrass thermotolerance. PMID:25050702

  3. Effect of acute heat stress on heat shock protein 70 messenger RNA and on heat shock protein expression in the liver of broilers.

    PubMed

    Gabriel, J E; Ferro, J A; Stefani, R M; Ferro, M I; Gomes, S L; Macari, M

    1996-05-01

    1. The synthesis of heat shock protein 70 (Hsp70) mRNA and the expression of Hsp70 in the liver of broiler chickens submitted to acute heat stress (35 degrees C for 5 h) was investigated. 2. Hsp70 expression was detected by SDS-PAGE and Western blot analysis using a polyclonal antiserum against Hsp70 of Blastocladiella emersonii. The specific signal of Hsp70 mRNA was analysed by Northern blot using as probe a Hsp70 cDNA of B. emersonii. 3. An increase in the amount of Hsp70 was detected from the first up to the fifth hour of acute heat exposure. This increase in the amount of Hsp70 was accompanied by an increase in Hsp70 mRNA which peaked at 3 h. 4. This study shows that the heat induced increase in Hsp70 mRNA and protein in broiler liver, in vivo, are time dependent, similar to that in mammals. PMID:8773853

  4. Investigation of heat transfer with film cooling to a flat plate in a shock tube

    NASA Astrophysics Data System (ADS)

    Jurgelewicz, Scott A.

    1989-12-01

    The heat transfer occurring through turbulent boundary layers in modern gas turbines is not well understood. The heat transferred to a flat plate though a turbulent boundary layer presents many similarities without the complex flow patterns. The gas used in this study was air. The flow behind a passing shock wave in a shock tube was used to simulate the high temperature ratio flows found in gas turbines. Highly responsive heat flux gages were used to measure the temperature history of a flat plate exposed to the flow. High speed digital recorders were used to sample and store the information. Heat transfer rates were determined from temperature history using a computer program and a quadrature method. The temperature history was numerically averaged to filter out noise effects before it was used to calculate the heat flux. It was found that low shock Mach numbers produced measured heat flux rates that were predictable by theory. At higher Mach numbers the rounded leading edge of the plate produced reflections that increased the measured heat flux as the Mach number increased; but theory, dependent on incident shock Mach number, underpredicted these actual values. Film cooling flows were then studied under the same flow conditions. Ratios of heat transfer coefficients with blowing ratios of approximately two to three produced the best agreement with correlations. The effects of free stream turbulence on the heat flux with film cooling were also briefly studied.

  5. Osmotic regulation of the heat shock response in H4IIE rat hepatoma cells.

    PubMed

    Schliess, F; Wiese, S; Haussinger, D

    1999-09-01

    The influence of cell hydration on the heat shock response was investigated in H4IIE hepatoma cells at the levels of HSP70 expression, MAP kinase activation, induction of c-jun and the MAP kinase phosphatase MKP-1, heat resistance, and development of tolerance/sensitization to arsenite after a priming heat treatment. Induction of HSP70, MKP-1, and c-jun by heat was delayed, but more pronounced or sustained, under hyperosmotic conditions compared with normo- and hypo-osmotically exposed cells. Anisosmolarity per se was ineffective to induce HSP70; some expression of the mRNAs for MKP-1 and c-jun in response to hyperosmolarity was found, but was small compared with the response to heat. Heat-induced activation of JNK-1 was increased under hyperosmotic conditions and more sustained than the JNK-activity induced by hyperosmolarity at 37 degrees C. A prominent Erk-2 activation was found immediately after heat shock under hypo- and normo-osmotic conditions, but Erk-2 activation was weak in hyperosmolarity-exposed cells. Despite anisosmotic alterations of the heat shock response at the molecular level, the heat resistance of H4IIE cells toward heat shock was not affected by ambient osmolarity. However, an osmolarity-dependent sensitization to arsenite was induced by a priming heat shock. The osmodependence of the H4IIE cell response to heat differs from that recently found in primary rat hepatocytes. The data are discussed in terms of cellular adaption mechanisms and their physiological relevance. PMID:10463947

  6. Dynamics of heat shock factor association with native gene loci in living cells.

    PubMed

    Yao, Jie; Munson, Katherine M; Webb, Watt W; Lis, John T

    2006-08-31

    Direct observation of transcription factor action in the living cell nucleus can provide important insights into gene regulatory mechanisms. Live-cell imaging techniques have enabled the visualization of a variety of intranuclear activities, from chromosome dynamics to gene expression. However, progress in studying transcription regulation of specific native genes has been limited, primarily as a result of difficulties in resolving individual gene loci and in detecting the small number of protein molecules functioning within active transcription units. Here we report that multiphoton microscopy imaging of polytene nuclei in living Drosophila salivary glands allows real-time analysis of transcription factor recruitment and exchange on specific native genes. After heat shock, we have visualized the recruitment of RNA polymerase II (Pol II) to native hsp70 gene loci 87A and 87C in real time. We show that heat shock factor (HSF), the transcription activator of hsp70, is localized to the nucleus before heat shock and translocates from nucleoplasm to chromosomal loci after heat shock. Assays based on fluorescence recovery after photobleaching show a rapid exchange of HSF at chromosomal loci under non-heat-shock conditions but a very slow exchange after heat shock. However, this is not a consequence of a change of HSF diffusibility, as shown here directly by fluorescence correlation spectroscopy. Our results provide strong evidence that activated HSF is stably bound to DNA in vivo and that turnover or disassembly of transcription activator is not required for rounds of hsp70 transcription. This and previous studies indicate that transcription activators display diverse dynamic behaviours in their associations with targeted loci in living cells. Our method can be applied to study the dynamics of many factors involved in transcription and RNA processing, and in their regulation at native heat shock genes in vivo. PMID:16929308

  7. Purification and characterization of a heat-shock element binding protein from yeast.

    PubMed Central

    Sorger, P K; Pelham, H R

    1987-01-01

    The promoters of heat shock genes are activated when cells are stressed. Activation is dependent on a specific DNA sequence, the heat-shock element (HSE). We describe the purification to homogeneity of an HSE-binding protein from yeast (Saccharomyces cerevisiae), using sequential chromatography of whole cell extracts on heparin-agarose, calf thymus DNA-Sepharose and an affinity column consisting of a repetitive synthetic HSE sequence coupled to Sepharose. The protein runs as a closely spaced doublet of approximately 150 kd on SDS-polyacrylamide gels; mild proteolysis generates a stable 70-kd fragment which retains DNA binding activity. The relative affinities of the protein for a range of variant HSE sequences correlates with the ability of these sequences to support heat-inducible transcription in vivo, suggesting that this polypeptide is involved in the activation of heat-shock promoters. However, the protein was purified from unshocked yeast, and may therefore represent an unactivated form of heat-shock transcription factor. Study of the purified protein should help to define the mechanistic basis of the heat-shock response. Images Fig. 2. Fig. 4. Fig. 5. Fig. 6. Fig. 7. PMID:3319580

  8. Phylogenetic analysis of heat shock proteins in Glassy-winged sharpshooter (Homalodisca vitripennis)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heat shock proteins were identified in the glassy-winged sharpshooter, GWSS, Homalodisca vitripennis. The overall importance and function of HSPs lie in their ability to maintain protein integrity and activity during stressful conditions, such as extreme heat, cold, drought, or other stresses. The G...

  9. Effects of Heat Shock on Amino Acid Metabolism of Cowpea Cells 1

    PubMed Central

    Mayer, Randall R.; Cherry, Joe H.; Rhodes, David

    1990-01-01

    When cowpea (Vigna unguiculata) cells maintained at 26°C are transferred to 42°C, rapid accumulation of γ-aminobutyrate (>10-fold) is induced. Several other amino acids (including β-alanine, alanine, and proline) are also accumulated, but less extensively than γ-aminobutyrate. Total free amino acid levels are increased approximately 1.5-fold after 24 hours at 42°C. Heat shock also leads to release of amino acids into the medium, indicating heat shock damage to the integrity of the plasmalemma. Some of the changes in metabolic rates associated with heat shock were estimated by monitoring the 15N labeling kinetics of free intracellular, extracellular and protein-bound amino acids of cultures supplied with 15NH4+, and analyzing the labeling data by computer simulation. Preliminary computer simulation models of nitrogen flux suggest that heat shock induces an increase in the γ-aminobutyrate synthesis rate from 12.5 nanomoles per hour per gram fresh weight in control cells maintained at 26°C, to as high as 800 nanomoles per hour per gram fresh weight within the first 2 hours of heat shock. This 64-fold increase in the γ-aminobutyrate synthesis rate greatly exceeds the expected (Q10) change of metabolic rate of 2.5- to 3-fold due to a 16°C increase in temperature. We suggest that this metabolic response may in part involve an activation of glutamate decarboxylase in vivo, perhaps mediated by a transient cytoplasmic acidification. Proline appears to be synthesized from glutamate and not from ornithine in cowpea cells. Proline became severalfold more heavily labeled than ornithine, citrulline and arginine in both control and heat-shocked cultures. Proline synthesis rate was increased 2.7-fold by heat shock. Alanine, β-alanine, valine, leucine, and isoleucine synthesis rates were increased 1.6-, 3.5-, 2.0-, 5.0-, and 6.0-fold, respectively, by heat shock. In contrast, the phenylalanine synthesis rate was decreased by 50% in response to heat shock. The

  10. Supercritical Collisionless Shocks as a Mechanism for Preferential Heating in Coronal Holes

    NASA Astrophysics Data System (ADS)

    Zimbardo, G.

    2009-12-01

    A long standing problem of the solar corona is that heavy ions in coronal holes are preferentially heated, that is, their temperature is larger than the proton temperature in a way that is more than mass proportional, T_i/T_p > m_i/m_p. Supercritical collisionless shocks can be generated in the reconnection outflow region due to the merging of small magnetic dipoles with the unipolar magnetic field of coronal holes. We present a new model which shows that preferential heating of heavy ions can be caused by ion reflection off quasi-perpendicular collisionless shocks. The ion energization is due to the motional electric field in the shock frame, which is perpendicular to the magnetic field by definition: this can explain the observed temperature anisotropy with large perpendicular temperature. In turn, the temperature anisotropy can cause ion cyclotron emission, as observed in proximity of the Earth's bow shock. In this respect, the paradigm of preferential heating by ion cyclotron resonance is turned upside down. Experimental evidence of heavy ion heating at interplanetary shocks by a number of spacecraft is discussed, as well as the possibility to have a sufficient number of collisionless shocks in the polar corona. The cross-disciplinary character of this study is also emphasized.