Biological role and regulation of the universally conserved heat shock proteins

Species-specific differences in acetaminophen hepatotoxicity depend on HSP70 expression level

Acetaminophen (N-Acetyl-p-aminophenol: APAP) is one of the most commonly used analgesic/antipyretic drugs with proven safety at therapeutic doses, however, over-dosage causes dose-dependent liver damage, leading to acute liver failure in severe cases. The level of APAP-induced liver injury has been known to vary amongst animal species, and APAP concentrations that induce cell death have been investigated using primary cultured cells. We constructed in vitro model of APAP-induced hepatotoxicity using mouse, rat and human hepatoma cell lines to investigate species differences in the APAP-induced cytotoxicity by monitoring cell death as a marker. The EC50 for each cell line was Hepa1-6 (mouse) < H-4-II-E (rat) < Hep3B (human), whilst the expression of heat shock protein 70 (HSP70), which was a typical molecular chaperone, positively correlated with the EC50 of each cell. Heat shock treatment, which caused activation of heat shock factor 1 (HSF1) followed by significant induction of HSP70, partially suppressed APAP-induced cell death in Hepa1-6 and H-4-II-E. Moreover, HSP70 or HSF1 siRNA treatment in Hep3B enhanced APAP-induced cell death. These results suggest that APAP-induced cell death in hepatoma cell lines may be partly mediated by protein denaturation and that the expression level of HSP70 has an inhibitory effect.

Heat Shock Protein Inhibitors Show Synergistic Antibacterial Effects with Photodynamic Therapy on Caries-Related Streptococci In Vitro and In Vivo

Caries are chronic infections in which the cariogenic biofilm plays a critical role in disease occurrence and progression. Photodynamic therapy (PDT) is a new effective treatment that is receiving wide attention in the antibacterial field, but it can lead to the upregulation of heat shock proteins (HSPs), which enhances bacterial resistance. Herein, we incorporated HSP inhibitors with PDT to evaluate the effect on Streptococcus mutans, Streptococcus sobrinus, and Streptococcus sanguinis under planktonic conditions and on cariogenic biofilms. Additionally, a model of caries was established in 2-week-old rats, and anticaries properties were evaluated by Keyes' scoring. Importantly, the combination of HSP inhibitors and PDT had outstanding efficiency in inhibiting the growth of tested Streptococcus strains and the formation of either monomicrobial or multispecies biofilms in vitro. In addition, the quantity of colonized streptococci and the severity of carious lesions were also distinctly suppressed in vivo. Overall, the synergistic application of HSP inhibitors and PDT has promising potential in the prevention and treatment of dental caries. IMPORTANCE Effective therapies for the prevention and control of caries are urgently needed. Cariogenic streptococci play a key role in the occurrence and progression of caries. Recently, photodynamic therapy has been demonstrated to have good antibacterial efficiency, but it can cause a heat shock response in bacteria, which may weaken its practical effects. We indicate here an effective therapeutic strategy of combining heat shock protein inhibitors and photodynamic therapy, which shows excellent inhibition toward three dominant streptococci related to caries and suppression of carious progression in a rat model. Further development for clinical application is promising.

Distinct patterns of responses in endothelial cells and smooth muscle cells following vascular injury

Vascular smooth muscle cells (SMCs) are heterogeneous, and their differential responses to vascular injury are not well understood. To address this question, we performed single-cell analysis of vascular cells to a ligation injury in mouse carotid arteries after 3 days. While endothelial cells had a homogeneous activation of mesenchymal genes, less than 30% of SMCs responded to the injury and generated 2 distinct clusters - i.e., proinflammatory SMCs and stress-responsive SMCs. Proinflammatory SMCs were enriched with high levels of inflammatory markers such as vascular cell adhesion molecule-1 while stress-responsive SMCs overexpressed heat shock proteins. Trajectory analysis suggested that proinflammatory SMCs were potentially derived from a specific subpopulation of SMCs. Ligand-receptor pair analysis showed that the interaction between macrophages and proinflammatory SMCs was the major cell-cell communication among all cell types in the injured arteries. In vitro coculture demonstrated that VCAM1+ SMCs had a stronger chemotactic effect on macrophage recruitment than VCAM1- SMCs. Consistently, the number of VCAM1+ SMCs significantly increased in injured arteries and atherosclerotic lesions of ApoE-/- mice and human arteries. These findings provide insights at the single-cell level on the distinct patterns of endothelial cells and SMC responses to vascular injury.

Chemistry and biosynthesis of bacterial polycyclic xanthone natural products

Covering: up to the end of 2021Bacterial polycyclic xanthone natural products (BPXNPs) are a growing family of natural xanthones featuring a pentangular architecture with various modifications to the tricyclic xanthone chromophore. Their structural diversities and various activities have fueled biosynthetic and chemical synthetic studies. Moreover, their more potent activities than the clinically used drugs make them potential candidates for the treatment of diseases. Future unraveling of structure activity relationships (SARs) will provide new options for the (bio)-synthesis of drug analogues with higher activities. This review summarizes the isolation, structural elucidation and biological activities and more importantly, the recent strategies for the microbial biosynthesis and chemical synthesis of BPXNPs. Regarding their biosynthesis, we discuss the recent progress in enzymes that synthesize tricyclic xanthone, the protein candidates for structural moieties (methylene dioxygen bridge and nitrogen heterocycle), tailoring enzymes for methylation and halogenation. The chemical synthesis part summarizes the recent methodology for the division synthesis and coupling construction of achiral molecular skeletons. Ultimately, perspectives on the biosynthetic study of BPXNPs are discussed.

Role of Heme Oxygenase in Gastrointestinal Epithelial Cells

The gastrointestinal tract is a unique organ containing both vascular and luminal routes lined by epithelial cells forming the mucosa, which play an important role in the entry of nutrients and act as a selective barrier, excluding potentially harmful agents. Mucosal surfaces establish a selective barrier between hostile external environments and the internal milieu. Heme is a major nutritional source of iron and is a pro-oxidant that causes oxidative stress. Heme oxygenases (HOs) catalyze the rate-limiting step in heme degradation, resulting in the formation of iron, carbon monoxide, and biliverdin, which are subsequently converted to bilirubin by biliverdin reductase. In gastrointestinal pathogenesis, HO-1, an inducible isoform of HO, is markedly induced in epithelial cells and plays an important role in protecting mucosal cells. Recent studies have focused on the biological effects of the products of this enzymatic reaction, which have antioxidant, anti-inflammatory, and cytoprotective functions. In this review, the essential roles of HO in the gastrointestinal tract are summarized, focusing on nutrient absorption, protection against cellular stresses, and the maintenance and regulation of tight junction proteins, emphasizing the potential therapeutic implications. The biochemical basis of the potential therapeutic implications of glutamine for HO-1 induction in gastrointestinal injury is also discussed.

Heme oxygenase-1 induction by heat shock in rat hepatoma cell line is regulated by the coordinated function of HSF1, NRF2, AND BACH1

The mechanism of heme oxygenase-1 (HO-1) induction by heat shock (HS) loading remains unclear. Here, we investigated the contribution of transcription factors to HS-induced HO-1 expression, using a rat hepatoma cell line (H-4-II-E). Our results demonstrated that HS treatment resulted in a marked induction of HO-1. Immunohistochemical analysis showed a slight mismatch in the expression levels of HO-1 and HSP70 by HS among cells, suggesting a conflict between multiple induction mechanisms. We observed HS-induced nuclear localization of, not only phosphorylated HSF1, but also NRF2, which is a typical transcription factor activated by oxidative stress. HSF1 knockdown in H-4-II-E markedly reduced HO-1 induction by HS, while NRF2 knockdown resulted in a partial effect. The chromatin immunoprecipitation assay demonstrated that HS loading resulted in significant binding of HSF1 to the HSE in the promoter proximal region of HO-1 gene and another HSE located close to the MARE in the -4 kb upstream enhancer region 1, where NRF2 also bound, together with BACH1, a negative transcription factor of HO-1. These observations indicate that HO-1 induction by HS is mainly mediated by HSF1 binding to the proximal HSE. NRF2 binding to MARE by HS is predominantly suppressed by an increased binding of BACH1.

Two calcium-binding chaperones from the fat body of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) involved in diapause

Molecular chaperones are crucial for the correct folding of newly synthesized polypeptides, in particular, under stress conditions. Various studies have revealed the involvement of molecular chaperones, such as heat shock proteins, in diapause maintenance and starvation; however, the role of other chaperones in diapause and starvation relatively is unknown. In the current study, we identified two lectin-type chaperones with calcium affinity, a calreticulin (LdCrT) and a calnexin (LdCnX), that were present in the fat body of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) during diapause. Both proteins possessed an N-globular domain, a P-arm domain, and a highly charged C-terminal domain, while an additional transmembrane domain was present in LdCnX. Phylogenetic analysis revealed distinction at the order level. Both genes were expressed in multiple tissues in larval and adult stages, and constitutively throughout development, though a starvation response was detected only for LdCrT. In females, diapause-related expression analysis in the whole body revealed an upregulation of both genes by post-diapause, but a downregulation by diapause only for LdCrT. By contrast, males revealed no alteration in their diapause-related expression pattern in the entire body for both genes. Fat body-specific expression analysis of both genes in relation to diapause revealed the same expression pattern with no alteration in females and downregulation in males by post-diapause. This study suggests that calcium-binding chaperones play similar and possibly gender-specific roles during diapause.

Antibodies to Heat Shock Proteins 90α and 90β in Psoriasis

One of many hypotheses of psoriasis pathogenesis supposes an overexpression of heat shock proteins (Hsps) in different skin layers and systemic immunologic response to them. Hsp90 is one of the most abundant chaperone in eukaryotic cells. The number of studies concerning the role of Hsp90 and anti-Hsp90 antibodies in etiopathogenesis of various diseases is also constantly expanding. Still, there are not many reports concerning potential involvement of this Hsp family or anti-Hsp90 immunization in pathomechanism of psoriasis. The aim of the study was the estimation of anti-Hsp90α and anti-Hsp90β IgG antibodies in the sera of the psoriatic patients at different phases of disease activity in comparison to the sera of healthy individuals. The study material consisted of sera from psoriasis patients (n = 80) in active phase and in the remission phase and healthy individuals (n = 80). Concentrations of anti-Hsp90α and anti-Hsp90β IgG antibodies were determined using ELISA technique. In the patients with psoriasis (both in the active phase of the disease and in the remission phase) concentrations of anti-Hsp90α antibodies were significantly higher than in healthy individuals and they correlated positively with psoriasis area severity index values. The mean concentrations of anti-Hsp90β antibodies in the psoriatic patients and healthy controls were comparable. The obtained results indicate an existence of increased immunological response to Hsp90α in psoriasis. It may suggest the role of the extracellular form of this chaperone and/or anti-Hsp90α antibodies in etiopathogenesis of this dermatosis. The inhibition of Hsp90α may represent a novel therapeutic approach to treat psoriasis.

Antiapoptotic Effect of β1 Blockers in Ascending Thoracic Aortic Smooth Muscle Cells: The Role of HSP70 Expression

Heat shock proteins (HSPs) play an important role in the cellular adaptation to stress, a requisite for cell survival. The aortic wall appears to be a target for increased expression of HSPs during surgical stress. We aimed to define the expression and function of aortic HSP70 in 31 patients with normal ascending thoracic aortic diameter who underwent aortic valve replacement due to aortic valve stenosis and in 35 patients with dilated ascending thoracic aorta who underwent replacement of an ascending thoracic aortic aneurysm. To elucidate responsible signaling mechanisms we used an in vitro model of rat hypoxic aortic vascular smooth muscle cell (AVSMC) cultures. We demonstrated an increase in AVSMC HSP70 and an attenuation of the apoptotic markers (TUNEL-positive nuclei, caspase-3 activity, Bax/Bcl2 ratio) in aortic wall tissue specimens from both aortic valve stenosis and ascending thoracic aortic aneurysm patients on β1 blockade with metoprolol. In vitro, metoprolol treatment of hypoxic rat AVSMCs increased nitric oxide (NO) production, induced heat shock factor 1 transport to the nucleus, upregulated HSP70, decreased p53 phosphorylation and attenuated apoptosis. Blockade of NO production, resulted in decreased HSP70 and prevented the metoprolol-induced anti-apoptotic response of hypoxic AVSMCs. We demonstrate an anti-apoptotic effect of metoprolol dependent on NO-induced HSP70 expression, and thus augmentation of HSP70 expression should be considered as a therapeutic approach to limit apoptosis in the human ascending thoracic aorta of patients undergoing cardiac surgery.

Heat Shock Proteins Can Be Surrogate Autoantigens for Induction of Antigen Specific Therapeutic Tolerance in Rheumatoid Arthritis

Technologies that enable induction of therapeutic tolerance may revolutionize the treatment of autoimmune diseases by their supposed potential to induce drug-free and lasting disease remission. In combination with diagnostic tests that screen for individuals at risk, these approaches may offer chances to halt disease before serious damage in the tissues can occur. In fact, for healthy individuals at risk, this could lead to a preventive form of vaccination. For therapeutic tolerance to re-instate natural self-tolerance it seems essential to induce tolerance for the critical autoantigens involved in disease. However, for most autoimmune diseases such antigens are poorly defined. This is the case for both disease inciting autoantigens and antigens that become involved through epitope spreading. A possible source of surrogate auto-antigens expressed in tissues during inflammation are heat shock proteins (HSP) or stress proteins. In this mini-review we discuss unique characteristics of HSP which provide them with the capacity to inhibit inflammatory processes. Various studies have shown that epitopes of HSP60 and HSP70 molecules can function as vaccines to downregulate a variety of autoimmune inflammatory diseases. Currently, several research groups are developing cell therapies with the intention to reach therapeutic tolerance. In this review, in which we are proposing to ex vivo load tolerant dendritic cells with a Treg inducing HSP70 derived peptide called B29, we are discussing the chances to develop this as an autologous tolDC therapeutic tolerance therapy for rheumatoid arthritis.

Heat shock protein 70 is induced by pepsin via MAPK signaling in human nasal epithelial cells

BACKGROUND

Recent studies have shown that laryngopharyngeal reflux is associated with chronic rhinosinusitis. Pepsin may be a key factor involved in the injury of nasal mucosal epithelial cells, but the pathogenesis remains unclear. We are to investigate whether a mitogen-activated protein kinase (MAPK) pathway regulates heat shock protein 70 (HSP70) expression in primary cultures of human nasal epithelial cells (HNEpCs) in response to pepsin stimulation.

METHODS

HSP70 protein expression levels in HNEpCs were estimated by Western blot analysis after treatment with pepsin. MAPK pathway activity levels were also evaluated to elucidate the mechanism underlying the effects of pepsin on HSP70 in HNEpCs. Inhibitors of signaling pathways were used to determine the contribution of MAPKs in HSP70 response after pepsin stimulation. Cellular apoptosis and cell viability in HNEpCs after treatment with pepsin were measured.

RESULTS

The expression of HSP70 increased after stimulation with pepsin and decreased after the removal of pepsin. Pepsin induced activation of p38, extracellular signal-regulated kinase 1/2, and c-Jun N-terminal kinase (JNK) 1/2. Inhibition of JNK1/2 reduced HSP70 expression in HNEpCs. The apoptosis in HNEpCs at 12 h after treatment with pepsin at pH 7.0 increased significantly when compared with the control and pH 7.0 groups. Cell viability decreased following exposure to pepsin at pH 7.0.

CONCLUSION

Pepsin, even under neutral pH 7.0, increases the expression of HSP70 in HNEpCs by activating the JNK/MAPK signaling pathway. Increased HSP70 may be the protective mechanism when pepsin presents in the other parts of the body.

Heat Shock Protein Alteration in the Gastrointestinal Tract Tissues of Chickens Exposed to Arsenic Trioxide

Arsenic (As) is widely distributed in our living environment and is useful for industry, agriculture, medical treatment, and other fields. Arsenic trioxide (As2O3) is an existing form of As. Exposure to As2O3 has a toxic effect on humans and animals. It not only leads to skin cancer, peripheral vascular disease, hyperkeratosis, etc. but also interferes with the functioning of the gastrointestinal tract. The gastrointestinal tract is an important organ for animals to transform the food they eat into the nutrients their body needs for maintenance and growth. Heat shock proteins (Hsps) exist in the non-stress normal cells and their expression increases under stimuli. Therefore, we wonder whether the "stimulus" of As2O3 could change the messenger RNA (mRNA) abundance and expression level of Hsps in the gastrointestinal tract of birds. To investigate the relation between arseniasis and Hsp alterations in the chicken's gastrointestinal tract induced by an As2O3-supplemented diet, we selected 72 one-day-old male Hy-line chickens and randomly divided them into four groups. They were fed either a commercial diet or an As2O3-supplemented diet containing 7.5, 15, and 30 mg/kg As2O3. The experiment lasted for 90 days, and gastrointestinal tract tissue samples (gizzard, glandular stomach, duodenum, jejunum, ileum, cecum, and rectum) were collected at 30, 60, and 90 days. The mRNA contents of Hsps (including Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90) were examined by real-time PCR (RT-PCR). The correlation between As2O3 and Hsp genes was assessed. In addition, the protein expression levels of Hsp60 and Hsp70 in the gastrointestinal tract tissue samples were measured by western blot. The results indicated that the mRNA expression levels and the Hsp expression levels in the gastrointestinal tract tissues of chickens with As2O3 supplementation increased at different time points in a dose-dependent manner (p < 0.05 or p < 0.01). These data suggested that arseniasis influenced the mRNA abundance of Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90 and the protein expression levels of Hsp60 and Hsp70 in the chicken's gastrointestinal tract tissues.

Photothermal stress triggered by near-infrared-irradiated carbon nanotubes up-regulates osteogenesis and mineral deposition in tooth-extracted sockets

PURPOSE

The bone regenerative healing process is often prolonged, with a high risk of infection particularly in elderly and diseased patients. A reduction in healing process time usually requires mechanical stress devices, chemical cues, or laser/thermal therapies. Although these approaches have been used extensively for the reduction of bone healing time, the exact mechanisms involved in thermal stress-induced bone regeneration remain unclear.

METHODS

Photothermal stress (PTS) stimulation was carried out using a novel photothermal device, composed of an alginate gel (AG) including carbon nanotubes (CNT-AGs) and their irradiator with near-infrared (NIR) light. We investigated the effects of optimal hyperthermia on osteogenesis, its signalling pathway in vitro and mineral deposition in tooth-extracted sockets in vivo.

RESULTS

The PTS (10 min at 42 °C, every day), triggered by NIR-induced CNT, increased the activity of alkaline phosphatase (ALP) in mouse osteoblast MC3T3-E1 cells in a time-dependent manner compared with the non-thermal stress control. PTS significantly induced the expression of osteogenic-related molecules such as ALP, RUNX2 and Osterix in a time-dependent manner with phosphorylated mitogen-activated protein kinases (MAPK). PTS increased the expression of heat shock factor (HSF) 2, but not HSF1, resulting in activation of heat shock protein 27. PTS significantly up-regulated mineral deposition in tooth-extracted sockets in normal and ovariectomised osteoporotic model mice in vivo.

CONCLUSIONS

Our novel CNT-based PTS up-regulated osteogenesis via activation of heat shock-related molecules, resulting in promotion of mineral deposition in enhanced tooth-extracted sockets.

FTSJ2, a heat shock-inducible mitochondrial protein, suppresses cell invasion and migration

Ribosomal RNA large subunit methyltransferase J (RrmJ), an Escherichia coli heat shock protein, is responsible for 2′-O-ribose methylation in 23S rRNA. In mammals, three close homologs of RrmJ have been identified and have been designated as FTSJ1, FTSJ2 and FTSJ3; however, little is known about these genes. In this study, we characterized the mammalian FTSJ2, which was the most related protein to RrmJ in a phylogenetic analysis that had similar amino acid sequence features and tertiary protein structures of RrmJ. FTSJ2 was first identified in this study as a nucleus encoded mitochondrial protein that preserves the heat shock protein character in mammals in which the mRNA expressions was increased in porcine lung tissues and A549 cells after heat shock treatment. In addition, a recent study in non-small cell lung cancer (NSCLC) suggested that the FTSJ2 gene is located in a novel oncogenic locus. However, our results demonstrate that the expression of FTSJ2 mRNA was decreased in the more invasive subline (CL1-5) of the lung adenocarcinoma cells (CL1) compared with the less invasive subline (CL1-0), and overexpression of FTSJ2 resulted in the inhibition of cell invasion and migration in the rhabdomyosarcoma cell (TE671). In conclusion, our findings indicate that mammalian FTSJ2 is a mitochondrial ortholog of E. coli RrmJ and conserves the heat shock protein properties. Moreover, FTSJ2 possesses suppressive effects on the invasion and migration of cancer cells.

Transposon mutagenesis of probiotic Lactobacillus casei identifies asnH, an asparagine synthetase gene involved in its immune-activating capacity

Lactobacillus casei ATCC 27139 enhances host innate immunity, and the J1 phage-resistant mutants of this strain lose the activity. A transposon insertion mutant library of L. casei ATCC 27139 was constructed, and nine J1 phage-resistant mutants out of them were obtained. Cloning and sequencing analyses identified three independent genes that were disrupted by insertion of the transposon element: asnH, encoding asparagine synthetase, and dnaJ and dnaK, encoding the molecular chaperones DnaJ and DnaK, respectively. Using an in vivo mouse model of Listeria infection, only asnH mutant showed deficiency in their ability to enhance host innate immunity, and complementation of the mutation by introduction of the wild-type asnH in the mutant strain recovered the immuno-augmenting activity. AsnH protein exhibited asparagine synthetase activity when the lysozyme-treated cell wall extracts of L. casei ATCC 27139 was added as substrate. The asnH mutants lost the thick and rigid peptidoglycan features that are characteristic to the wild-type cells, indicating that AsnH of L. casei is involved in peptidoglycan biosynthesis. These results indicate that asnH is required for the construction of the peptidoglycan composition involved in the immune-activating capacity of L. casei ATCC 27139.

A protective Hsp70-TLR4 pathway in lethal oxidant lung injury

Administering high levels of inspired oxygen, or hyperoxia, is commonly used as a life-sustaining measure in critically ill patients. However, prolonged exposures can exacerbate respiratory failure. Our previous study showed that TLR4 confers protection against hyperoxia-induced lung injury and mortality. Hsp70 has potent cytoprotective properties and has been described as a TLR4 ligand in cell lines. We sought to elucidate the relationship between TLR4 and Hsp70 in hyperoxia-induced lung injury in vitro and in vivo and to define the signaling mechanisms involved. Wild-type, TLR4(-/-), and Trif(-/-) (a TLR4 adapter protein) murine lung endothelial cells (MLECs) were exposed to hyperoxia. We found markedly elevated levels of intracellular and secreted Hsp70 from wild-type mice lungs and MLECs after hyperoxia. We confirmed that Hsp70 and TLR4 coimmunoprecipitate in lung tissue and MLECs. Hsp70-mediated NF-κB activation appears to depend upon TLR4. In the absence of TLR4, Hsp70 loses its protective effects in endothelial cells. Furthermore, these protective properties of Hsp70 are TLR4 adapter Trif dependent and MyD88 independent. Hsp70-deficient mice have increased mortality during hyperoxia, and lung-targeted adenoviral delivery of Hsp70 effectively rescues both Hsp70-deficient and wild-type mice. To our knowledge, our studies are the first to define an Hsp70-TLR4-Trif cytoprotective axis in the lung and endothelial cells. This pathway is a potential therapeutic target against a range of oxidant-induced lung injuries.

Heat shock protein genes (hsp20, hsp75 and hsp90) from Pieris rapae: molecular cloning and transcription in response to parasitization by Pteromalus puparum

Most molecular work on the roles of heat shock proteins (hsps) in host-parasite interaction has focused on vertebrates, rather than invertebrates. Here the full length complementary DNA (cDNA) sequences of three hsp genes (hsp20, hsp75 and hsp90) were amplified from Pieris rapae, and their transcriptional responsiveness to parasitization by the endoparasitic wasp Pteromalus puparum were investigated. The cDNA sequence analysis of hsp20, hsp75 and hsp90 revealed open reading frames of 531, 2 328 and 2 157 bp in length, which encode proteins with calculated molecular weights of 19.5, 75.48 and 82.7 kDa, respectively. The comparison of amino acid sequences showed that P. rapae hsp20 shared highly divergent homology to that of other insects, while hsp75 and hsp90 showed high homology to their counterparts of other species. The expression analysis indicated that these three genes were influenced in response to parasitization by P. puparum. The hsp20 transcripts in parasitized pupae were higher compared to non-parasitized pupae. The expression of hsp75 and hsp90 were down-regulated following parasitization. The results indicate that hsps are involved in host-parasitoid interactions.

Fungal Hsp90: a biological transistor that tunes cellular outputs to thermal inputs

Heat shock protein 90 (HSP90) is an essential, abundant and ubiquitous eukaryotic chaperone that has crucial roles in protein folding and modulates the activities of key regulators. The fungal Hsp90 interactome, which includes numerous client proteins such as receptors, protein kinases and transcription factors, displays a surprisingly high degree of plasticity that depends on environmental conditions. Furthermore, although fungal Hsp90 levels increase following environmental challenges, Hsp90 activity is tightly controlled via post-translational regulation and an autoregulatory loop involving heat shock transcription factor 1 (Hsf1). In this Review, we discuss the roles and regulation of fungal Hsp90. We propose that Hsp90 acts as a biological transistor that modulates the activity of fungal signalling networks in response to environmental cues via this Hsf1-Hsp90 autoregulatory loop.

Recognition of heat shock protein 60 epitopes in children with type 1 diabetes

BACKGROUND

Treatment with a specific HSP60 epitope in new onset of type 1 diabetes (T1D) patients has been shown to preserve endogenous insulin production. Previously, recognition of pan HLA-DR-binding HSP60 epitopes in various autoimmune diseases was found; this study investigated recognition of these epitopes in newly diagnosed T1D patients and correlated findings to the occurrence of a partial remission.

METHODS

Peripheral blood mononuclear cells of 18 children with T1D were prospectively collected at disease onset and a few months after diagnosis. Epitope-specific T-cell proliferation and cytokine production (intracellular and in culture supernatants) were measured. Results were compared with 31 longstanding T1D patients and ten healthy controls.

RESULTS

Although HSP60 epitope-specific T-cell proliferative responses were detected, overall proliferative responses were low. At onset, epitope-specific intracellular IFN-γ production was higher in T1D patients compared with healthy controls (p < 0.05). At follow-up, both IL-10 and IFN-γ production were higher in those without a partial remission than in those with a partial remission (both p < 0.05). Also, IL-10 and IFN-γ production were higher compared with onset for patients without a PR (both p < 0.01). In supernatants of HSP60 epitope-specific T-cell cultures, no substantial differences in cytokine production were found between T1D patients with and without a partial remission, either at onset or a few months after onset. As patient numbers were small, results should be interpreted with caution.

CONCLUSIONS

Pan-DR-binding HSP60 peptides induced low peptide-specific proliferative responses and peptide-specific production of some, mainly intracellular, cytokines in T1D patients. Recognition did not differ significantly between patient groups and various time points.

Expression of a malarial Hsp70 improves defects in chaperone-dependent activities in ssa1 mutant yeast

Plasmodium falciparum causes the most virulent form of malaria and encodes a large number of molecular chaperones. Because the parasite encounters radically different environments during its lifecycle, many members of this chaperone ensemble may be essential for P. falciparum survival. Therefore, Plasmodium chaperones represent novel therapeutic targets, but to establish the mechanism of action of any developed therapeutics, it is critical to ascertain the functions of these chaperones. To this end, we report the development of a yeast expression system for PfHsp70-1, a P. falciparum cytoplasmic chaperone. We found that PfHsp70-1 repairs mutant growth phenotypes in yeast strains lacking the two primary cytosolic Hsp70s, SSA1 and SSA2, and in strains harboring a temperature sensitive SSA1 allele. PfHsp70-1 also supported chaperone-dependent processes such as protein translocation and ER associated degradation, and ameliorated the toxic effects of oxidative stress. By introducing engineered forms of PfHsp70-1 into the mutant strains, we discovered that rescue requires PfHsp70-1 ATPase activity. Together, we conclude that yeast can be co-opted to rapidly uncover specific cellular activities mediated by malarial chaperones.

Synergistic promotion of breast cancer cells death by targeting molecular chaperone GRP78 and heat shock protein 70

Heat shock protein 70 (HSP70) is frequently overexpressed in a variety of human malignancies and protects cancer cells against apoptosis in response to various stresses. The bioflavonoid quercetin inhibits HSP70 expression and induces cancer cells apoptosis. In the present study, we have investigated the effects of HSP70 down-regulation on the unfolded protein response (UPR) and addressed a novel strategy to enhance the proapoptotic effect of quercetin by suppressing GRP78 induction simultaneously. Treatment of human breast cancer cells with quercetin down-regulates HSP70 expression, but up-regulates GRP78 expression in a dose-dependent manner. Down-regulation of HSP70 by small interfering RNA also leads to induction of GRP78. Moreover, our studies reveal that HSP70 knockdown or quercetin induces other typical components of the UPR, including CHOP expression, eIF2α and JNK phosphorylation, caspases activation and XBP-1 splicing. Abrogating the induction of pro-survival chaperone GRP78 by small interfering RNA sensitizes breast cancer cells to quercetin. Colony survival assays demonstrate that treatment of breast cancer cells with green tea (−)-epigallocatechin gallate (EGCG), which binds to the ATP-binding domain of GRP78 and blocks its protective function, synergistically promoted quercetin-induced cell death. These studies reveal that HSP70 down-regulation leads to the induction of UPR. The pro-survival GRP78 induction contributes to quercetin resistance. Abrogation of GRP78 induction or inhibition of GRP78 activity increases the effectiveness of quercetin. These findings indicate that combinational administration of flavonoids capable of suppressing HSP70 and GRP78 such as quercetin and EGCG might represent a novel approach for cancer therapy or chemoprevention.

J domain co-chaperone specificity defines the role of BiP during protein translocation

Hsp70 chaperones can potentially interact with one of several J domain-containing Hsp40 co-chaperones to regulate distinct cellular processes. However, features within Hsp70s that determine Hsp40 specificity are undefined. To investigate this question, we introduced mutations into the ER-lumenal Hsp70, BiP/Kar2p, and found that an R217A substitution in the J domain-interacting surface of BiP compromised the physical and functional interaction with Sec63p, an Hsp40 required for ER translocation. In contrast, interaction with Jem1p, an Hsp40 required for ER-associated degradation, was unaffected. Moreover, yeast expressing R217A BiP exhibited defects in translocation but not in ER-associated degradation. Finally, the genetic interactions of the R217A BiP mutant were found to correlate with those of known translocation mutants. Together, our results indicate that residues within the Hsp70 J domain-interacting surface help confer Hsp40 specificity, in turn influencing distinct chaperone-mediated cellular activities.

Inducible heat shock protein 70 enhances HPV31 viral genome replication and virion production during the differentiation-dependent life cycle in human keratinocytes

Increasing data indicate heat shock proteins (HSPs) including inducible HSP70 (HSP70i) are involved in the replicative cycles of various viruses including adenoviruses (Ads), polyomaviruses (PyVs), and some RNA viruses. Cell-free system studies implicate HSP70i in human papillomavirus type 11 (HPV11) genome replication with E1 and E2 proteins, and there is evidence that HSP70 is involved in capsid assembly and disassembly for PyVs and HPVs. HSP70 expression is increased in HPV16 E6/E7 gene transduced human primary keratinocytes, and frequently detected in early stage uterine cervical cancer at levels in conjunction with lesion severity. In this study we carry out analyses in the natural host epithelial tissues to assess the role of inducible HSP70 (HSP70i) in the HPV infectious life cycle. For these studies we used the organotypic (raft) culture system to recapitulate the full viral life cycle of the high-risk HPV31. Upon heat shock of HPV31-infected organotypic tissues, we find high and sustained expression of HSP70i coincident with enhanced HPV genome replication and virion production. Whereas there is no clear effect on L1 expression levels, we find HSP70i and L1 interact and HSP70i colocalizes with and enhances the nuclear localization of L1 in differentiated cells. Ad-mediated gene transfer was used to study the effects of HSP70i in naturally HPV-infected differentiating tissues and showed results similar to those in heat shocked rafts. These results indicate that increased HSP70i augments late activities in the viral life cycle. We conclude that HSP70i contributes directly to HPV replicative viral activities and the production of infectious virions.

Proteomics analysis of Lactobacillus casei Zhang, a new probiotic bacterium isolated from traditional home-made koumiss in Inner Mongolia of China

Lactobacillus casei Zhang, isolated from traditional home-made koumiss in Inner Mongolia of China, was considered as a new probiotic bacterium by probiotic selection tests. We carried out a proteomics study to identify and characterize proteins expressed by L. casei Zhang in the exponential phase and stationary phase. Cytosolic proteins of the strain cultivated in de Man, Rogosa, and Sharpe broth were resolved by two-dimensional gel electrophoresis using pH 4-7 linear gradients. The number of protein spots quantified from the gels was 487 +/- 21 (exponential phase) and 494 +/- 13 (stationary phase) among which a total of 131 spots were identified by MALDI-TOF/MS and/or MALDI-TOF/TOF according to significant growth phase-related differences or high expression intensity proteins. Accompanied by the cluster of orthologous groups (COG), codon adaptation index (CAI), and GRAVY value analysis, the study provided a very first insight into the profile of protein expression as a reference map of L. casei. Forty-seven spots were also found in the study that showed statistically significant differences between exponential phase and stationary phase. Thirty-three of the spots increased at least 2.5-fold in the stationary phase in comparison with the exponential phase, including 19 protein spots (e.g. Hsp20, DnaK, GroEL, LuxS, pyruvate kinase, and GalU) whose intensity up-shifted above 3.0-fold. Transcriptional profiles were conducted to confirm several important differentially expressed proteins by using real time quantitative PCR. The analysis suggests that the differentially expressed proteins were mainly categorized as stress response proteins and key components of central and intermediary metabolism, indicating that these proteins might play a potential important role for the adaptation to the surroundings, especially the accumulation of lactic acid in the course of growth, and the physiological processes in bacteria cell.

P-glycoprotein (multi-xenobiotic resistance) and heat shock protein gene expression in the reef coral Montastraea franksi in response to environmental toxicants

The deleterious impacts of marine pollutants on reef corals and their symbiotic algae are an important element of global coral reef decline. In the current study we examined the impacts of toxicants on the reef coral Montastraea franksi by analysing the expression of three stress-related genes belonging to the coral host, using Taqman real-time quantitative reverse transcription-PCR. Gene expression profiles of P-glycoprotein (or multi-xenobiotic resistance protein) (P-gp); heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90) were examined following 4 and 8h exposures to the heavy metal copper (3, 10, 30 and 100 microgL(-1)) or the third generation oil dispersant Corexit9527 (1, 5, 10 and 50 ppm). Additionally, the expression of P-gp was examined following exposure to 0.5 and 5 microM concentrations of the chemotherapeutic drug vinblastine, a classic substrate of P-gp. The expression of P-gp increased significantly in corals treated with vinblastine and also increased following exposure to copper and Corexit9527. Hsp70, and to a lesser extent Hsp90 expression increased following exposure to copper and Corexit9527 indicating a general cellular stress response. Densities of symbiotic algae in the tissues of the corals did not change significantly during the experiments, nor was any loss or paling of coral tissues observed. These findings provide important insight into how corals defend themselves against pollution and complement ongoing initiatives developing molecular biomarkers of stress in reef-building corals.

Molecular cloning and characterization of heat shock protein 70 from Trichinella spiralis

A cDNA encoding heat shock protein 70 of Trichinella spiralis (Ts-Hsp70) was identified by immunoscreening the adult T. spiralis cDNA library with rabbit antisera against T. spiralis adult extracts. The open reading frame of Ts-Hsp70 cDNA encoded a 623-amino acid peptide with a predicted molecular weight of 68.7kDa, which shares a high degree of sequence conservation with HSP70s from other parasites. Recombinant Ts-Hsp70 was expressed in Escherichia coli and purified with nickel column chromatography. Western blot analysis showed that recombinant Ts-Hsp70 could be recognized not only by trichinellosis patient sera, but also by T. spiralis-infected sera from rabbits, swine, and mice. Mice vaccinated with recombinant Ts-Hsp70 formulated with Freund's adjuvant exhibited strong humoral immune responses indicated by high titer of IgG antibody and significant muscle larval reduction (37%) after being challenged with T. spiralis larvae. The present results indicate that Ts-Hsp70 is a possible candidate vaccine against T. spiralis infection.

Hsp70-1 from Plasmodium falciparum: protein stability, domain analysis and chaperone activity

P. falciparum contains six copies of the Hsp70 gene of which PfHsp70-1 is important in the parasite's lifecycle. The protein consists of two domains like other Hsp70s but has an unusually long C-terminal tail. The full-length protein is stable towards high temperatures and chemical denaturants. Fluorescence and circular dichroism studies demonstrate that the approximately 42 kDa N-terminal/nucleotide-binding domain (NBD) is relatively unstable in isolation. Addition of the approximately 35 kDa C-terminal domain with an extended tail containing an EEVD motif confers thermal stability and makes it less susceptible to thermal denaturation. This suggests that the C-terminal domain functions as a stabilization domain. PfHsp70-1 possesses a chaperone activity in addition to other functions reported earlier. We report that the chaperone activity of PfHsp70-1 is enhanced in the presence of P. falciparum Hsp40 (Pfj1, PFD0465w), the homolog of bacterial DnaJ. The present work represents the first evidence for functional interactions between the PfHsp70-1 and Pfj1.

Isolation and identification procedure for Staphylococcus aureus in laboratory mice and rats by combined use of chromogenic X-SA agar and specific polymerase chain reaction

Generally, a conventional culture-based examination procedure (detection by egg-yolk salt agar and subsequent identification by phenotypic tests) for confirmation of the presence of S. aureus (SA) in laboratory mice and rats requires approximately 4 days. To improve the culture-based examination procedure for SA in terms of rapidity and reliability, combined use of chromogenic X-SA agar (XSA) and PCR using newly designed specific primers for SA (XSA-PCR) that can shorten the examination time (25.5 hr) was compared with the conventional procedure for SA. In 425 samples from mice and rats, 193 suspected isolates were detected by egg-yolk salt agar (EYSA), and 216 suspected isolates were detected by XSA. In the subsequent identification, 189 of 193 suspected isolates detected by EYSA were identified as SA by phenotypic tests (97.9%), and all 216 suspected isolates detected by XSA were identified as SA by PCR (100%). All SA-positive samples by the conventional procedure were included in the SA-positive samples by XSA-PCR. As a result, XSA-PCR was superior to the conventional procedure in detection rate and identification rate of SA. Therefore, XSA-PCR appears to be an effective tool for examination of SA in laboratory mice and rats that improves precision and shortens the examination time.

Functional characterization of the DnaK chaperone system from the archaeon Methanothermobacter thermautotrophicus DeltaH

We characterized the biochemical and functional properties of the DnaK system from the archaeon Methanothermobacter thermautotrophicus DeltaH. In contrast to the eubacterial chaperone components the archaeal Hsp70 system shows thermal transitions only slightly above the optimal environmental temperature (65 degrees C). Nevertheless, it prevents aggregation of luciferase in the physiological temperature range of the organism, but is also fully functional at 30 degrees C in luciferase refolding. Additionally, GrpE(M.th.) and DnaJ(M.th.) substitute their eubacterial counterparts whereas DnaK(M.th.) is only functional with its native cochaperones which could be attributed to a functional specialization of the eubacterial chaperones during evolution.

Year in review 2007: Critical Care--multiple organ failure and sepsis

Several research papers published in Critical Care throughout 2007 examined the pathogenesis, diagnosis, treatment and prognosis of sepsis and multiorgan failure. The present review summarizes the findings and implications of the papers published on sepsis and multiorgan failure and places the research in the context of other work in the field.

Reverse engineering: the architecture of biological networks

We adopt a control theory approach to reverse engineer the complexity of a known system--the bacterial heat shock response. Using a computational dynamic model, we explore the organization of the heat shock system and elucidate its various regulation strategies. We show that these strategies are behind much of the complexity of the network. We propose that complexity is a necessary outcome of robustness and performance requirements that are achieved by the heat shock system's exquisite regulation modules. The techniques we use rely on dynamic computational models and principles from the field of control theory.

Oxalate exposure provokes HSP 70 response in LLC-PK1 cells, a line of renal epithelial cells: protective role of HSP 70 against oxalate toxicity

We investigated the effects of oxalate on immediate early genes (IEGs) and stress protein HSP 70, commonly induced genes in response to a variety of stresses. LLC-PK1 cells were exposed to oxalate. Gene transcription and translation were monitored by Northern and Western blot analysis. RNA and DNA synthesis were assessed by [(3)H]-uridine and [(3)H]-thymidine incorporation, respectively. Oxalate exposure selectively increased the levels of mRNA encoding IEGs c-myc and c-jun as well as stress protein HSP 70. While expression of c-myc and c-jun was rapid (within 15 min to 2 h) and transient, HSP 70 expression was delayed (approximately 8 h) and stable. Furthermore, oxalate exposure resulted in delayed induction of generalized transcription by 18 h and reinitiation of the DNA synthesis by 24 h of oxalate exposure. Moreover, we show that prior induction of HSP 70 by mild hypertonic exposure protected the cells from oxalate toxicity. To the best of our knowledge this is the first study to demonstrate rapid IEG response and delayed heat-shock response to oxalate toxicity and protective role of HSP 70 against oxalate toxicity to renal epithelial cells. Oxalate, a metabolic end product, induces IEGs c-myc and c-jun and a delayed HSP 70 expression; While IEG expression may regulate additional genetic responses to oxalate, increased HSP 70 expression would serve an early protective role during oxalate stress.

Genome-wide analysis of the interaction between the endosymbiotic bacterium Wolbachia and its Drosophila host

Background

Intracellular Wolbachia bacteria are obligate, maternally-inherited, endosymbionts found frequently in insects and other invertebrates. The success of Wolbachia can be attributed in part to an ability to alter host reproduction via mechanisms including cytoplasmic incompatibility (CI), parthenogenesis, feminization and male killing. Despite substantial scientific effort, the molecular mechanisms underlying the Wolbachia/host interaction are unknown.

Results

Here, an in vitro Wolbachia infection was generated in the Drosophila S2 cell line, and transcription profiles of infected and uninfected cells were compared by microarray. Differentially-expressed patterns related to reproduction, immune response and heat stress response are observed, including multiple genes that have been previously reported to be involved in the Wolbachia/host interaction. Subsequent in vivo characterization of differentially-expressed products in gonads demonstrates that Angiotensin Converting Enzyme (Ance) varies between Wolbachia infected and uninfected flies and that the variation occurs in a sex-specific manner. Consistent with expectations for the conserved CI mechanism, the observed Ance expression pattern is repeatable in different Drosophila species and with different Wolbachia types. To examine Ance involvement in the CI phenotype, compatible and incompatible crosses of Ance mutant flies were conducted. Significant differences are observed in the egg hatch rate resulting from incompatible crosses, providing support for additional experiments examining for an interaction of Ance with the CI mechanism.

Conclusion

Wolbachia infection is shown to affect the expression of multiple host genes, including Ance. Evidence for potential Ance involvement in the CI mechanism is described, including the prior report of Ance in spermatid differentiation, Wolbachia-induced sex-specific effects on Ance expression and an Ance mutation effect on CI levels. The results support the use of Wolbachia infected cell cultures as an appropriate model for predicting in vivo host/Wolbachia interactions.

Antioxidative properties of human milk and spermine are not related to expression of Hsp 70

AIM

Heat shock proteins (Hsps) have been detected in various tissues, including those in the intestines, and play a role in cellular protection. Polyamines, such as spermine (SPM), are found in human milk (HM) and act as antioxidants. We hypothesized that the antioxidative property of SPM is related to the expression of Hsp and examined this relationship in an intestinal epithelial cell (IEC) line.

METHOD

(i) Confluent IEC-6 cells were exposed to mild heat shock (43 degrees C, 1 h) and then allowed to recover at 37 degrees C for 24 h. Hydrogen peroxide (H(2)O(2)) was applied to induce oxidative stress and cell viability was evaluated. (ii) Cells were exposed to mild heat shock or pre-incubated with HM or pre-incubated with 5 microM SPM for 24 h. Hsp70 expression in IEC-6 cells was analysed by Western blot.

RESULTS

The survival rate of cells treated with mild heat shock after H(2)O(2) challenge was significantly higher than that of non-pretreated cells. Western blot analysis demonstrated that Hsp70 was expressed in IEC-6 cells treated with mild heat shock but not in IEC-6 cells pre-incubated with HM or 5 microM SPM.

CONCLUSION

Mild heat shock treatment induces Hsp70, which acts as an antioxidant in IEC-6 cells, but HM or SPM does not induce Hsp70 in this system.

Cellular responses of rat periodontal ligament cells under hypoxia and re-oxygenation conditions in vitro

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the responses of periodontal ligament cells under hypoxia and re-oxygenation conditions in vitro.

MATERIAL AND METHODS

Periodontal ligament fibroblasts were isolated from rat incisors. In the hypoxia group, cells were incubated in 2% O(2) for 1-3 d. In the re-oxygenation group, cells were first incubated under the same conditions as the hypoxia group for 24 h and then were returned to normoxic conditions and cultured for 1-2 additional days.

RESULTS

Proliferation ratios increased in all groups in a time-dependent manner. Proliferation ratios in both the hypoxia and re-oxygenation groups were significantly higher than in the control group on days 2 and 3. Alkaline phosphatase activity was significantly higher in the hypoxia group than in the control and the re-oxygenation groups. The expression of bone sialoprotein mRNA was significantly higher in the hypoxia group than in the control group on days 1 and 2. The expression of vascular endothelial growth factor mRNA was significantly higher in the hypoxia group than in the control group on days 1 and 2. In the re-oxygenation group, the level of expression of bone sialoprotein mRNA and vascular endothelial growth factor mRNA were similar to those of the control group. The expression of heat shock protein 70 mRNA in the hypoxia group was similar to that in the control group, whereas in the re-oxygenation group it was statistically higher than in the other groups.

CONCLUSION

These results suggest that periodontal ligament cells maintain their osteogenic ability in hypoxia and re-oxygenation conditions in vitro.

Relative importance of amino acids, glycine-betaine and ectoine synthesis in the biocontrol agent Pantoea agglomerans CPA-2 in response to osmotic, acidic and heat stress

AIMS

The objective of this work was to determine the role of different compatible solutes in adaptation of Pantoea agglomerans CPA-2 at different stages of growth to solute (0.98, 0.97, 0.96 aw), heat (35 and 40 degrees C) and acidic (pH 4.0, 5.0, 6.0) stress.

METHODS AND RESULTS

Solute stress was imposed by using NaCl, glucose or glycerol, and pH was imposed with malic and citric acids. The accumulation of glycine-betaine, ectoine and amino acids in bacterial cells was quantified using high performance liquid chromathography (HPLC). There was a significant (P<0.05) accumulation of glycine-betaine (NaCl modified, 100-150 micromol g(-1) dry weight of cells) and ectoine (glucose modified media, >340 micromol g(-1) dry weight of cells) in the cells over a 48 h incubation period when compared with controls (<10 micromol g(-1) dry weight of cells). Chromatographic profile of amino acids was different with respect to control when NaCl or glucose was used as osmolyte.

CONCLUSIONS

Pantoea agglomerans CPA-2 cells synthesised significant amounts of glycine-betaine and ectoine in response to imposed solute stress. However, these compounds and tested amino acids were not involved in cellular adaptation to either heat or pH stress.

SIGNIFICANCE AND IMPACT OF THE STUDY

This type of information can be effectively applied to improve ecophysiological quality of cells of bacterial biocontrol agents for better survival and biocontrol efficacy in the phyllosphere of plants.

Heat shock protein gene 70-2 polymorphism is differentially associated with the clinical phenotypes of ulcerative colitis and Crohn's disease

BACKGROUND AND AIM

A single nucleotide polymorphism in heat shock protein 70-2 (HSP70-2) has been shown to be associated with a severe clinical course in Crohn's disease (CD), but it is not known if such a relationship exists in ulcerative colitis (UC). The aim of the present study was to identify associations between the HSP70-2 polymorphism and the clinical courses of CD and UC in Koreans.

METHODS

Restriction fragment length polymorphism analysis was performed for HSP70-2 polymorphisms using the PstI-cleavage site present in the B allele but not in the A allele of the DNA obtained from 101 patients with CD, 144 patients with UC, and 245 age- and sex-matched healthy controls. Study subjects were classified by disease behavior, severity and extent of disease.

RESULTS

In CD, multivariate analysis showed that the AA genotype of HSP70-2 polymorphisms was associated with non-perforating disease (OR 10.10, 95% CI 1.66-15.38) and male sex (OR 3.56, 95% CI 1.04-12.23), and that the BB genotype was associated with severe CD (OR 12.03, 95% CI 1.60-101.56). In contrast, multivariate analysis for UC showed that the AA genotype was associated with severe UC (OR 2.02, 95% CI 1.34-3.03).

CONCLUSIONS

CD patients with BB genotype of HSP70-2 polymorphism tend to experience a more severe clinical course and allele A is associated with more severe UC. HSP70-2 polymorphism may be used to predict CD and UC phenotypes, which can illuminate immunological differences in CD and UC.

The dnaJ gene as a novel phylogenetic marker for identification of Vibrio species

The utility of the dnaJ gene for identifying Vibrio species was investigated by analyzing dnaJ sequences of 57 type strains and 22 clinical strains and comparing sequence homologies with those of the 16S rDNA gene and other housekeeping genes (recA, rpoA, hsp60). Among the 57 Vibrio species, the mean sequence similarity of the dnaJ gene (77.9%) was significantly less than that of the 16S rDNA gene (97.2%), indicating a high discriminatory power of the dnaJ gene. Most Vibrio species were, therefore, differentiated well by dnaJ sequence analysis. Compared to other housekeeping genes, the dnaJ gene showed better resolution than recA or rpoA for differentiating Vibrio coralliilyticus from Vibrio neptunius and Vibrio harveyi from Vibrio rotiferianus. Among the clinical strains, all 22 human pathogenic strains, including an atypical strain, were correctly identified by the dnaJ sequence. Our findings suggest that analysis of the dnaJ gene sequence can be used as a new tool for the identification of Vibrio species.

dnaJ gene sequence-based assay for species identification and phylogenetic grouping in the genus Staphylococcus

In the last few years, many attempts have been made to use conserved gene sequences for identification and for phylogenetic studies of Staphylococcus species. In an effort to identify a more reliable approach, a dnaJ gene sequence-based database was created. In this study, an approximately 883 bp portion of the dnaJ gene sequence from 45 staphylococcal type strains was compared with 16S rRNA and other conserved gene (hsp60, sodA and rpoB) sequences available in public databases. Nucleotide sequence comparisons revealed that the staphylococcal dnaJ gene showed higher discrimination (mean similarity 77.6 %) than the 16S rRNA (mean similarity 97.4 %), rpoB (mean similarity 86 %), hsp60 (mean similarity 82 %) and sodA (mean similarity 81.5 %) genes. Analysis of the dnaJ gene sequence from 20 Staphylococcus isolates representing two clinically important species showed <1 % sequence divergence. Phylogenetic data obtained from the dnaJ gene sequence were in general agreement with those of 16S rRNA gene sequence analysis and DNA-DNA reassociation studies. In conclusion, the dnaJ gene sequence-based assay is an effective alternative to currently used methods, including 16S rRNA gene sequencing, for identification and taxonomical analysis of Staphylococcus species.