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PubMed1999

Oral lichen planus: an immunohistochemical study of heat shock proteins (HSPs) and cytokeratins (CKs) and a unifying hypothesis of pathogenesis.

The expression of heat shock proteins HSP60 and HSP70 and cytokeratins CK1/10 and CK7/18 were compared in epithelium of oral lichen planus (OLP) lesions and oral fibromas using an avidin-biotin-peroxidase complex (ABC) immunohistochemical method. An immunostaining intensity distribution (IID) index was developed to assess staining intensity and the proportion of positively stained cells in different layers of the epithelium. The expression of HSP60 in the basal layer was significantly higher in OLP than in fibromas. No difference in HSP70 expression was evident between OLP and fibromas. The expression of CK1/10 in the epithelial basal and suprabasal layers was significantly higher in OLP than in fibromas. There was no demonstrable staining for CK7/18 in either OLP or fibromas. A significant correlation was evident between the expression of HSP60 and CK1/10 in the basal epithelial cells in OLP. The findings support a role for HSP60 in the pathogenesis of OLP. A unifying hypothesis of the pathogenesis of OLP, involving two sequential immune reactions, is proposed.

Adult↗
PubMed2002

Ovariectomy upregulates expression of estrogen receptors, NOS, and HSPs in porcine platelets.

Platelets participate in normal and pathological thrombotic processes. Hormone replacement in postmenopausal women is associated with increase risk for thrombosis. However, little is known regarding how platelets are affected by hormonal status. Nitric oxide (NO) modulates platelet functions and is modulated by hormones. Therefore, the present study was designed to determine how loss of ovarian hormones changes expression of estrogen receptors and regulatory proteins for NO synthase (NOS) in platelets. Estrogen receptors (ER alpha and ER beta), NOS, heat shock proteins 70 and 90 (HSP70 and HSP90), caveolin-1, -2, and -3, calmodulin, NOS activity, and cGMP were analyzed in a lysate of platelets from gonadally intact and ovariectomized female pigs. Expression of ER beta and ER alpha receptors, endothelial NOS (eNOS), HSP70, and HSP90 increased with ovariectomy. NOS activity and cGMP also increased; calmodulin was unchanged. Caveolins were not detected. These results suggest that ovarian hormones influence expression of estrogen receptors and eNOS in platelets. Changes in estrogen receptors and NOS could affect platelet aggregation in response to hormone replacement.

Animals↗
PubMed2004

[Study on the neurotoxicity and brain tissue HSPs level in benzo[a]pyrene exposed mice].

OBJECTIVE: To study the neurotoxicity and brain tissue HSP70, HSP90 beta level in benzo [a]pyrene exposed mice. METHODS: 50 Kunming mice were divided into 5 groups randomly, the exposed groups(3 dose level groups), the vehicle control group and the standard control group, every group get 10 mice. The exposed groups were administrated by intraperitoneal injection with BaP dissolved in vegetable oil at 7.8, 3.2 and 1.3 mg/kg BW once, 4 times/week specially, the vehicle control group was given vegetable oil parallel and the standard control group was not given additional treatment. Observing general conditions and nerve symptoms of the animals. After 8 weeks experiments, the mice were killed and the brains were removed. Detect the ratio of brain-weight/body-weight and the Hsp70 and Hsp90 beta level of the mice brain homogenate by the method of western blot. RESULTS: 1. In the high and medium dose groups, the brain-weight was lower than that of control groups. In the high dose group, the ratio of brain-weight/body-weight was lower than that of other groups. 2. In the low dose BaP group, HSP70 level were much higher than that of control groups. In the medium dose BaP group and high dose BaP group, HSP90 beta level were higher than that of control groups. CONCLUSION: BaP can damage the never system of the mice; the high the dose was, the high the HSPs90 level were.

Animals↗
PubMed2005

[Expression and prognostic significance of survivin and caspase-3 in esophageal squamous-cell carcinoma and their relationship with HSPs expression].

OBJECTIVE: To explore the prognostic significance of expression of survivin and caspase-3 in esophageal squamous-cell carcinoma (ESCC) and the relasionship with expression of heat shock proteins 27 and 70 (HSP27 and HSP70). METHODS: Expressions of survivin and caspase-3 in 101 cases of ESCC were quantitatively detected with flow cytometry. Their expressions in long-term survival group (group A, >or= 5 years, 38 cases) were compared with those in the short-term survival group (group B, 0.05). The positive expression rate of survivin in group A was significantly lower than that in group B (31.6% vs 54.0%, P = 0.029). Compared with that in short-term survival group, the strong positive expression rate of caspase-3 in long-term survival group was significantly higher (47.6% vs. 68.4%, P = 0.042). Positive expression rate of caspase-3 showed decreasing tendency with increase in age. No significant differences in clinicopathologic features in relation to expression rate of caspase-3 other than tumor length. No correlation was observed between expression intensity of survivin and any clinicopathologic features. Logistic regression analysis indicated that survivin and caspase-3 expressions were of independent prognostic significance for ESCC. There was no association between survivin and caspase-3 expression and expression of HSP27 and HSP70. CONCLUSION: The expressions of survivin and caspase-3 are two independent prognostic factors in ESCC. They do not correlate with HSP27 and HSP70 expression.

Adult↗
PubMed1994

Redox mechanism for the chaperone activity of heat shock proteins HSPs 60, 70 and 90 as suggested by hydrophobic cluster analysis: hypothesis.

We have recently shown that the N-terminal ATPase fragment of hsp70 (1-375, composed of domains I and II) as well as the subsequent domain III (376-520) may share three-dimensional similarities with hsp60. In this study, we propose that domain III, common to the hsp60s and hsp70s is also found in the hsp90s and adopts a beta-alpha-beta Rossmann-folded structure which is encountered in the NAD-binding domain of dehydrogenases. Consequently, with the help of the domain IV (in hsp70s and hsp90s) or of hsp10/GroES (in hsp60s) and possibly that of auxilliary partners, the hsp molecules could act as "unfoldases" or "reset systems" by disrupting secondary structures through redox reactions on the main polypeptidic chain with which they interact. The models built on this hypothesis may open up a new way for understanding the chaperone functions within the folding/unfolding processes.

Chaperonin 60↗
PubMed2004

Molecular chaperones: proposal of a systematic computer-oriented nomenclature and construction of a centralized database.

Molecular chaperones are a wide group of unrelated protein families whose role is to assist others proteins. Comparably, under environmental stress, stress proteins behave as biocatalysts of protein stabilization. Stress proteins include a large class of proteins that were originally termed heat shock proteins (HSPs) due to their initial discovery in tissues exposed to elevated temperatures. Many, but not all, stress proteins and HSPs are molecular chaperones. Moreover, not all HSPs are derivable from stress. HSPs are structurally diversified by the contribution of various domains having specific roles. HSPs have been grouped, mainly on the basis of their molecular masses, into specific families that include small HSPs (sHSPs)/alpha-crystallins, HSP10s, HSP40s, HSP60s, HSP70s, HSP90s, HSP100s and HSP110s. The names of these major families are historical artefacts with limited information content. Using the current databases, names and proteic domains of many molecular chaperones in different species were analyzed. Although traditional names of HSPs are trivial, it is unrealistic to suggest replacing them, because they are preferred and widely used. Here we suggest that these traditional names be chaperoned, in silico, by a systematic nomenclature. Thus, for example, with the same intent of use of [trioxygen: O3] for ozone, we propose here C7HSP70[Ehsa]ER-P11021 for GRP78 (78 kDa endoplasmic Human molecular chaperone in HSP70 superfamily with P11021 as its accession number in the database of the National Center for Biotechnology Information (NCBI)). The proposed systematic computer-oriented naming and classification method is designed for HSPs and also their partners based on the number of amino acids, domain structure, phylogenetic domain, localization in the cell and accession number as stated in the NCBI. Arabidopsis thaliana was analyzed as a model, because it contains a large number of various HSPs localized in several organelles. Overall, this naming system helps in building, optimizing and managing a novel online database entirely devoted to HSPs. The purported taxonomy, coupled with the newly constructed database, can contribute to studies involving large amounts of stored data on HSPs.

Databases, Protein↗
PubMed2006

Peripheral blood mononuclear cell responses to heat shock proteins in patients undergoing stem cell transplantation.

GVHD is a major complication after allogeneic SCT. Etiology of GVHD is multifactorial. Known role of hSPS in antigen presentation could suggest their potential role in the alloreactive process that leads to aGVHD. HSPS represent major immunodominant antigens in a wide spectrum of microbial pathogens. Bacterial and fungal colonization, infection and sepsis are frequent in immunocompromised patients with various malignant and non-malignant diseases. We studied PBMC responses to recombinant human hsp60 (rh-hsp60), rh-hsp70 and Mycobacterium bovis hsp65 (M. bovis hsp65) in relation to aGVHD and infection in 34 pediatric patients with various lympho-hemopoietic malignancies as well as non-malignant disorders subjected to SCT. PBMC of patients before initiation of preparative regimen as well as after engraftment were stimulated with hSPS (1 microg/mL/well, 7-day cultivation). PHA was used as a control of the stimulation ability. Cell responses were measured after the incorporation of 3H-thymidin (pulsing with 1 microCi/well) and were expressed as stimulation indexes (SI). We demonstrated significantly high proliferative response to rh-hsp60 as well as M. bovis hsp65 in a cohort of pretransplant patients with anamnestic and/or actual infection when compared with a cohort of patients without infection and healthy individuals. Strong PBMC cell responses to hSPS were found in patients who were at present colonized with Escherichia coli and Klebsiella pneumoniae or had previously K. pneumoniae infection with subsequent sepsis. Our findings support various studies dealing with immunodominant hSPS in connection with several pathogens and infectious diseases. Although no statistical difference for proliferative response to PHA was observed, PBMC responses against all tested hSPS comparing a cohort of patients with aGVHD and that with no sign of GVHD resulted in significantly lower SI for all tested hSPS in patients with aGVHD. Lower stimulation with hSPS during aGVHD might be explained by the stress-induced upregulation of self-hSPS synthesis that might lead to the inhibition of self-hSPS reactive T-cell response. Vice versa, we hypothesize that increased hsp-specific stimulation may reflect the presence of protecting regulatory T cells preventing the development of Th1-mediated diseases involving aGVHD.

Adolescent↗
PubMed2002

Role of heat shock proteins in atherosclerosis.

Heat shock proteins (HSPs) are present in most cells, serving as molecular chaperones, and they play a role in cell protection from damage in response to stress stimuli. However, accumulating data indicate the involvement of HSPs in the pathogenesis of diseases. The aim of this article is to update the progress concerning the role of HSPs in atherosclerosis. It has been demonstrated that HSPs are highly expressed in the atherosclerotic lesions of humans, rabbits, and apolipoprotein E-deficient mice. Risk factors for atherosclerosis, eg, infections, oxidized low density lipoprotein, oxidative stress, hypertension, and biomechanical stress, evoke HSP overexpression in endothelial cells, macrophages, and smooth muscle cells via activation of heat shock transcription factor 1. Interestingly, HSPs, normally localized within the cell, have been found as a soluble form in the blood, which is positively correlated with atherosclerosis in humans. Recently, several groups have reported that soluble HSPs specifically bind to the Toll-like receptor 4/CD14 complex, initiating an innate immune response, including the production of proinflammatory cytokines by macrophages and adhesion molecules in endothelial cells via nuclear factor-kappaB activation. Furthermore, the titers of autoantibodies against HSPs are significantly elevated in patients with atherosclerosis, and T lymphocytes specifically responding to HSPs have been found in atherosclerotic plaques. These proinflammatory responses and autoimmune reactions to HSPs in the vessel wall can contribute to the initiation and perpetuation of atherosclerosis. Thus, HSPs have a general role in the response of the arterial wall to stress and may serve as a mediator/inducer of atherosclerosis in particular circumstances.

Animals↗
PubMed2000

Heat shock proteins in the pathogenesis of inflammatory skin diseases.

Heat shock proteins (HSPs) are highly conserved molecules and distributed widely in nature. They are also distributed in the skin, however, only limited information is available on the role of HSPs in the skin diseases. Immunohistochemical study of HSPs in the skin revealed that HSPs are differently expressed in the epidermal cells of patients with systemic lupus erythematosus (SLE), atopic dermatitis, graft versus host disease (GVHD) and so on. In normal healthy skin HSPs are constantly expressed in the epidermal cells. HSPs are expressed in the skin according to the influence of both external and internal milieu of the diseased conditions. Cytokines released in the skin strongly affect to express HSPs in epidermal cells. HSPs expressed in the skin can be targets for infiltrated T cells to modulate immune response of skin diseases. Roles of HSPs in the pathogenesis of SLE, GVHD, atopic dermatitis and psoriasis are discussed in this review. HSPs play an important role in the pathogenesis of many inflammatory skin diseases. They can be the molecules to evaluate both diseased conditions and inflammatory process of the skin diseases.

Cytokines↗
PubMed2007

Chaperones as part of immune networks.

Network theory is increasingly accepted as a basic regulatory mechanism in diverse immunological functions. Heat shock proteins (Hsps) are involved in multiple networks in the immune system. Hsps themselves (foreign or endogenous) activate innate immunity and play important roles to deliver self or nonself materials to antigen presenting cells. However, Hsps are immunodominant antigens during infectious diseases making self Hsps endangered targets of autoimmunity by cross-reactive clones. Therefore, it is not surprising that the mechanism of protection of self Hsps is not clonal deletion in natural self tolerance; rather, self Hsps are protected by active regulating natural autoimmunity. The active regulatory/protective immunity is accomplished by natural autoantibodies and regulatory T cells, both recognizing Hsps. The multiple involvements of Hsps in immune networks make them ideal targets of therapy in autoimmune diseases. Indeed, immunotherapy with Hsps was recently reported to be effective treatment modality against cancer, arthritis or diabetes mellitus.

Animals↗
PubMed1991

Analysis of conserved domains identifies a unique structural feature of a chloroplast heat shock protein.

A low molecular weight heat shock protein which localizes to chloroplasts has been identified in several plant species. This protein belongs to a eukaryotic superfamily of small HSPs, all of which contain a conserved carboxyl-terminal domain. To investigate further the structure of this HSP, we isolated and sequenced cDNA clones for the chloroplast LMW HSPs from Petunia hybrida and Arabidopsis thaliana. The cloning of chloroplast HSPs from these two species enabled us to compare the amino acid sequences of this protein from plant species (petunia, Arabidopsis, pea, soybean and maize) that represent evolutionarily divergent taxonomic subclasses. Three conserved regions were identified, which are designated as regions I, II and III. Regions I and II are also shared by cytoplasmic LMW HSPs and therefore are likely to have functional roles common to all eukaryotic LMW HSPs. In contrast, consensus region III is not found in other LMW HSPs. Secondary structure analysis predicts that this region forms an amphipathic alpha-helix with high conservation of methionine residues on the hydrophobic face and 100% conservation of residues on the hydrophilic face. This structure is similar to three helices, termed "methionine bristles", which are found in a methionine-rich domain of a 54 kDa protein component of signal recognition particle (SRP54). The conservation of regions I and II among LMW cytoplasmic and chloroplast HSPs suggests that these HSPs perform related functions in different cellular compartments. However, identification of the methionine bristle domain suggests that chloroplast HSPs also have unique functions or substrates within the special environment of the chloroplast or other plastids.

Amino Acid Sequence↗
PubMed1993

Heat shock (stress) proteins and autoimmunity in rheumatic diseases.

The rheumatic diseases (RDs) are characterized by acute and chronic inflammation, and autoimmunity plays a major role in their pathogenesis. RDs are for the most part of unknown etiology, but recent evidence indicates that heat shock or stress proteins (HSPs) may have an important role in the etiology/pathogenesis of RDs. HSPs are produced by prokaryotic and eukaryotic cells and are grouped according to molecular weight. Phylogenetically, HSPs are very old and are remarkably conserved molecules in evolution from bacteria to humans. HSPs are induced by a variety of cellular stresses in addition to heat; cognates are expressed constitutively and are essential in a number of normal functions. Some HSPs serve as molecular chaperones, the latter defined as proteins that mediate folding of other polypeptides and either promote their assembly into oligomeric structures or disassemble the final product. Conservation of structure and function of many HSPs may provide a link between immunity to infection and the autoimmune features of RDs. Evidence is reviewed from clinical and laboratory observations that diverse microbial agents, including viruses, bacteria, and parasites, may have putative roles in the development and pathogenesis of some RDs. HSPs also are discussed in relation to the major histocompatibility complex, HLA antigens, and disease associations and how they may alter the balance between tolerance and autoimmunity. Studies are reviewed that are supportive or nonsupportive of the concept of microbial infection associated with autoimmunity; individuals first react to microbial immunizations or infections with enhanced cellular/humoral responses to the agent's HSPs. With the enhanced immune response, cross-reactivity may occur with an HSP of the stressed host because of structural similarities to the microbial HSP. If all of these events occur, the host's homologous HSP or stressed cells now become true autoantigen(s). This sequence has implications for the etiology of immune-mediated RDs, the concept of epitope sharing, and the accompanying autoimmunity. A recurring theme emphasized in some reports to understand better the role of HSPs in autoimmunity is the need to select patients with early-onset disease. A minor subpopulation of T lymphocytes express a CD3-associated T-cell receptor (TCR) heterodimer composed of gamma and delta polypeptide chains. The gamma delta + T cells have several unique features. When analyzed by the polymerase chain reaction, lymphocytes with TCR-gamma delta appear to reflect the polyclonal expansion of preexisting gamma delta clones. They are found in peripheral lymphoid tissue in very low percentage (< 5%) but may represent the majority of T cells within epithelial tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1995

Heat shock (stress) proteins and gamma delta T lymphocytes in oral lichen planus.

OBJECTIVE: Heat shock proteins (Hsps), a highly conserved class of protective cellular proteins that are produced under various conditions of environmental challenge, have been implicated as the antigenic stimulus in autoimmune diseases. Because lichen planus (LP) appears to be an autoimmune or hyperimmune condition (mediated by T cells), Hsps may have a role in the pathogenesis of this disease. We believe that if keratinocyte Hsps are antigenic targets of a cellular immune response, upregulation of these proteins should be demonstrable in tissue sections. STUDY DESIGN: Immunohistochemistry was used to evaluate expression of several families of Hsps in oral lichen planus tissues. The number and distribution of gamma delta T cells, a subset of T lymphocytes with an immune surveillance function that may contribute to autoimmunity, were also evaluated. Monoclonal antibodies to Hsps 27, 60, 70, 90, gamma delta receptor, and CD3 (pan-T lymphocyte marker) were incubated with frozen sections of LP (n = 22) and normal oral mucosa (n = 17) followed by an avidin-biotin-peroxidase labeling method. Antibodies to bacterial Hsps (GroEL and DnaK) were used as negative controls, and antibody to constitutive eukaryotic Hsp (Hsc70) was used as a positive control. RESULTS: In six cases of LP, basal keratinocytes stained intensely for Hsp27, whereas controls showed only slight staining. Otherwise LP and normal tissues showed comparable positive staining of upper level keratinocytes with anti-Hsp27. Subjective increases in antibody staining were noted for Hsp60 in LP, which was due in part to staining of infiltrating lymphocytes and in part to keratinocyte expression. Normal tissues showed weak basal cell antibody staining for Hsp60. Hsp70 staining was observed at a less intense level in LP than in controls. Except for more intense basement membrane staining with anti-Hsp90 antibody in gingiva and palate, no differences in the occurrence of this protein were found. Absolute numbers of gamma delta T cells were increased in LP when compared with those in control specimens (n = 10 vs n = 1, respectively, per high-power field). However, gamma delta T cells represented less than 1% of the CD3+ lymphocytes. CONCLUSIONS: It was concluded that normal oral mucosa expresses Hsps 27, 60, 70, and 90 and contains few gamma delta T cells. Although the expression of Hsps was altered in LP, the differences demonstrated were slight and were therefore inconclusive. The Hsps expressed in LP could have contributed to the persistence or chronicity of the disease, or they could have simply reflected cellular injury.

Antibodies, Monoclonal↗
PubMed1998

Differential localization of heat shock proteins 90, 70, 60 and 27 in human decidua and placenta during pregnancy.

Little is known about the localization of heat shock proteins (HSPs) in the decidua and placenta during the course of normal pregnancy. In this study, we have examined the localization of the HSPs in decidual and placental tissues obtained from women during the first, second and third trimesters of pregnancy (five in each trimester) by immunohistochemistry using highly specific antisera. HSPs 90, 70, 60 and 27 were detected in decidual stromal cells during each trimester. The intensity of staining did not change during gestation for HSPs 60 and 27, whereas it decreased with advancing gestation for HSPs 90 and 70. HSPs 90 and 60 were localized primarily in the nucleus, whereas HSP 70 was present equally in the nucleus and the cytoplasm; HSP 27 was primarily in the cytoplasm. In the placenta, HSPs 90, 70 and 60 were localized in cytotrophoblast, syncytiotrophoblast, intermediate trophoblast, Hofbauer and endothelial cells. HSPs 90 and 60 were localized primarily in the nucleus, while HSP 70 was in the nucleus and the cytoplasm. In the placenta, HSP 27 was detected only in the intermediate trophoblast and syncytiotrophoblast cells and only in the first two trimesters. These results indicate that there are striking differences in the subcellular localization of HSPs in the decidua and the placenta during normal pregnancy.

Chaperonin 60↗
PubMed1993

Expression of Low Molecular Weight Heat-Shock Proteins under Field Conditions.

Heat-shock proteins (HSPs) are known to be expressed in plants experiencing high-temperature stress. We have examined the expression of class I cytoplasmic low molecular weight (LMW) HSPs and find that these HSPs also frequently accumulate in seeds, seed pods, and flowers during a normal growing season. We first examined the expression of class I cytoplasmic LMW HSPs by western blot analysis in a range of seed samples from both commercially grown and wild legumes. LMW HSPs were present in all seed samples, indicating that these HSPs are regularly expressed in these tissues. To examine more specifically conditions under which LMW HSPs were produced during an average growing season, additional studies of Medicago sativa were carried out during the fall season in Tucson, AZ. Plants were irrigated to avoid conditions of water stress, and canopy temperature was monitored throughout the study period. LMW HSP expression in leaves, flowers, and developing seed pods was analyzed by western blotting. Results show that in the field HSPs are frequently produced in flowers and seed pods, even in plants that show no HSP expression in leaves. Parallel greenhouse studies indicate that HSP expression in seeds is in part developmentally regulated. In total our data suggest a more widespread occurrence of HSPs in optimal growth environments and emphasize their potential role during reproduction.

Journal Article↗
PubMed1987

Early and late heat shock proteins in wheats and other cereal species.

Coleoptiles and roots of 3-day-old seedlings from five cereal species (Triticum aestivum L., T. durum Desf., Hordeum vulgare L., Secale cereale L., and Triticale) respond to heat shock at 40 degrees C by synthesizing a new set of 13 strong bands (as revealed by one-dimensional sodium dodecyl sulfate gel electrophoresis) as well as some 20 degrees C proteins. Heat shock proteins (HSPs) belong to three different size groups: high molecular mass HSPs in the 103 to 70 kilodalton range, intermediate molecular mass HSPs in the 62 to 32 kilodalton range, and low molecular mass HSPs about 17 to 16 kilodalton in size. At the beginning of the heat shock coleoptiles show a reduced ability to synthesize intermediate molecular mass HSPs but after 4 hours at 40 degrees C they exhibit fully developed HSP patterns identical to that found in roots. Synthesis of early HSPs declines after 7 hours of treatment followed by the appearance of a new set of 12 protein bands (late HSPs) in the ranges 99 to 83, 69 to 35, and 15 to 14 kilodaltons. After 12 hours at 40 degrees C, three other late HSPs of 89, 45, and 38 kilodalton are induced. The induction of late HSPs after 7 hours at 40 degrees C appears to be associated with an enhancement of radioactive methionine incorporation into proteins.

Journal Article↗
PubMed1992

A class of soybean low molecular weight heat shock proteins : immunological study and quantitation.

Two major polypeptides of the 15- to 18-kilodalton class of soybean (Glycine max) heat shock proteins (HSPs), obtained from an HSP-enriched (NH(4))(2)SO(4) fraction separated by two-dimensional polyacrylamide gel electrophoresis, were used individually as antigens to prepare antibodies. Each of these antibody preparations reacted with its antigen and cross-reacted with 12 other 15- to 18-kilodalton HSPs. With these antibodies, the accumulation of the 15- to 18-kilodalton HSPs under various heat shock (HS) conditions was quantified. The 15- to 18-kilodalton HSPs began to be detectable at 35 degrees C, and after 4 hours at 40 degrees C they had accumulated to a maximum level of 1.54 micrograms per 100 micrograms of total protein in soybean seedlings and remained almost unchanged up to 24 hours after HS. Accumulation of the HSPs was reduced at temperatures higher than 40 degrees C. At 42.5 degrees C the HSPs were reduced to 1.02 micrograms per 100 micrograms, and at 45 degrees C they were hardly detectable. A brief HS at 45 degrees C (10 minutes), followed by incubation at 28 degrees C, which also induced HSP synthesis, resulted in synthesis of this class of HSPs at levels up to 1.06 micrograms per 100 micrograms of total protein. Taking into consideration the previous data concerning the acquisition of thermotolerance in soybean seedlings, our estimation indicates that the accumulation of the 15- to 18-kilodalton HSPs to 0.76 to 0.98% of total protein correlated well with the establishment of thermotolerance. Of course, other HSPs, in addition to this group of proteins, may be required for the development of thermotolerance.

Journal Article↗