Characterization of an inducible HSP70 gene in Chilo suppressalis and expression in response to environmental and biological stress Abstract The highly conserved heat shock protein 70 (HSP70) contributes to survival at a cellular level and greatly enhances stress tolerance in many organisms. In this study, we isolate and characterize Cshsp702, which encodes an inducible form of HSP70 in the rice stem borer, Chilo suppressalis. Cshsp702 does not contain introns; the translational product is comprised of 629 amino acids with an isoelectric point of 5.69. Real-time quantitative PCR revealed that Cshsp702 was expressed at maximal levels in hemocytes and was minimally expressed in the midgut. Expression of Cshsp702 in response to a range of temperatures (−11 to 43 °C) indicated significant induction by extreme cold and hot temperatures, with maximum expression after 2 h at 42 °C. The induction of Cshsp702 in response to the endoparasite Cotesia chilonis was also studied; interestingly, Cshsp702 expression in C. suppressalis was significantly induced at 24 h and 5 days, which correspond to predicted times of C. chilonis feeding and growth, respectively. The potential induction of Cshsp702 as an inflammatory response due to parasitic stress is discussed. In conclusion, Cshsp702 is induced in response to both environmental and biotic stress and plays an important role in the physiological adaptation of C. suppressalis.

Effects of abiotic stress on the expression of Hsp70 genes in Sogatella furcifera (Horváth) Abstract Sogatella furcifera (Horváth), a prominent rice pest in Asia, is a typical R-strategic and highly adaptable insect. Heat shock proteins (Hsps) are highly conserved molecular chaperones regulating responses to various abiotic stresses; however, limited information is available regarding their role in responding to abiotic stress in S. furcifera. This study aimed to investigate the effect of abiotic stresses on the expression of Hsp70 genes in the S. furcifera. Five Hsp70 genes were isolated from S. furcifera, and the expression patterns at different developmental stages and temperatures, upon treatment with different insecticides and ultraviolet A (UV-A) stress, were analyzed. Hsp70 genes were expressed at different developmental stages. Hsp70-2, Hsp70-5, and Hsp70-6 were significantly upregulated upon heat shock at 40 °C for 30 min. Hsp70-3 and Hsp70-4 were significantly upregulated upon heat shock at 30 °C for 30 min. Under UV-A stress, Hsp70-3, Hsp70-4, Hsp70-5, and Hsp70-6 were significantly upregulated. Conversely, Hsp70-2 was significantly downregulated under UV-A stress. The five Hsp70 genes were significantly downregulated in 3rd-instar nymphs on exposure to thiamethoxam, buprofezin, and avermectin at LC10 and LC25 concentrations. Hence, Hsp70 genes significantly contribute to the tolerance of S. furcifera to temperature and UV-A stress; however, they are not involved in the response to insecticides.

Correction to: Molecular basis for efficacy of Guduchi and Madhuyashti feeding on different environmental stressors in Drosophila It has come to authors’ attention that an inadvertent mistake was made in the construction of Figure 4 and Figure 6 of the original publication.

Effects of thermal stress on mortality and HSP90 expression levels in the noble scallops Chlamys nobilis with different total carotenoid content Abstract The noble scallop Chlamys nobilis is an economically important marine bivalve cultivated in the southern sea of China since the 1980s. Unfortunately, mass mortality of this scallop species often occurs in summer. The present study was conducted to investigate whether the expression of heat shock protein 90 (HSP90) and level of carotenoids could enhance high-temperature stress resistance in scallop. First, the HSP90 homolog of C. nobilis (designated CnHSP90) was identified and cloned. The complete cDNA sequence of CnHSP90 was 2631 bp, including a 2181-bp open reading frame (ORF) encoding a 726 amino acid polypeptide with five HSP90 family signatures, and sharing high homology with members of the HSP90 family. CnHSP90 was ubiquitously expressed in all examined tissues including the intestine, kidney, adductor, mantle, gill, and gonad, with the highest in the gonad. Golden and brown scallops, which contain significantly different total carotenoid content (TCC), were subjected to acute thermal challenge, and the LTE50 (semi-lethal temperature at 36 h heat shock) and LTI50 (semi-lethal time after heat shock) as well as the correlation between CnHSP90 gene expression and TCC were determined. The LTE50 of golden scallop (32.14 °C) was higher than that of brown scallops (31.19 °C), with longer LTI50 at all tested temperatures, indicating that golden scallops were more resistant to thermal stress than brown scallops. Similarly, the mRNA expression levels of CnHSP90 in gill of golden scallops were significantly higher (P < 0.05) than that of brown scallops at 6, 12, 24, and 36 h, with a strong positive correlation between CnHSP90 expression level and TCC. This suggests that both carotenoids and HSP90 levels could improve thermal resistance in the noble scallops.

Chronic corticosterone exposure induces liver inflammation and fibrosis in association with m 6 A-linked post-transcriptional suppression of heat shock proteins in chicken Abstract Our previous study had shown that chronic corticosterone (CORT) exposure causes excessive fat deposition in chicken liver, yet it remains unknown whether it is associated with inflammation and fibrosis. In general, heat shock proteins (HSPs) are activated in response to acute stress to play a cytoprotective role, and this activation is associated with m6A-mediated post-transcriptional regulation. However, changes of HSPs and the m6A methylation on their mRNAs in response to chronic CORT treatment in chicken liver have not been reported. In this study, chronic CORT exposure induced inflammation and fibrosis in chicken liver, associated with significantly modulated expression of HSPs that was significantly upregulated at mRNA level yet downregulated at protein level. Concurrently, m6A methyltransferases METTL3 content was upregulated together with the level of m6A methylation on HSPs transcripts. The m6A-seq analysis revealed 2-6 significantly (P < 0.05) hypermethylated m6A peaks in the mRNA of 4 different species of HSPs in CORT-treated chicken liver. HSP90B1 transcript had 6 differentially methylated m6A peaks among which peaks on exon 16 and exon 17 showed 3.14- and 4.72-fold of increase, respectively. Mutation of the 8 predicted m6A sites on exon 16 and exon 17 resulted in a significant (P < 0.05) increase in eGFP-fused content of HSP90B1 exon 16 and exon 17 fragment in 293 T cells, indicating a possible role of m6A in post-transcriptional regulation of HSPs. In conclusion, chronic CORT exposure induces inflammation and fibrosis in chicken liver along with an increase in the levels and m6A methylation of several HSPs mRNAs; HSPs levels were however reduced under the indicated conditions. Results presented suggest that the reduction in HSPs levels may be associated with m6A methylation in CORT-exposed chickens.

Impaired heat shock protein 72 expression in women with polycystic ovary syndrome following a supervised exercise programme Abstract Induction of heat shock protein expression and the heat shock (stress) response are seen in exercise. This exercise-induced response is thought protective against cellular stress through the expression of heat shock proteins. The highly inducible heat shock protein 72 (HSP72) has been shown to be expressed in a number of stress-related conditions, but not investigated in women with polycystic ovary syndrome (PCOS). Twenty-one women (10 controls, 11 with PCOS) concluded an 8-week supervised, moderate-intensity exercise programme. Monocytes and lymphocytes were analysed by flow cytometry for HSP72 expression from blood samples prior to, mid-way and at the completion of the programme. The monocyte HSP72 expression showed an increase from baseline values through mid-way (p = 0.025), and at the completion of the programme (p = 0.011) only in the control group, the PCOS group showed no significant change. This pattern was similar for lymphocyte HSP72 expression where a significant increase was found at the completion of the programme (p = 0.01) only in the control group. The magnitude of increased HSP72 expression following completion of the programme was linked to baseline values only in the control group. In conclusion, increased HSP72 expression to exercise over an 8-week period was seen in control but not in PCOS women, suggesting that there is an impairment of HSP72 expression in response to exercise in these women.

Response to oxidative stress of peripheral blood mononuclear cells from multiple sclerosis patients and healthy controls Abstract The complex scenario of multiple sclerosis (MS) pathology involves several mechanisms, including oxidative stress response. The heat shock proteins (HSPs) are important for the protection of the cells; however, their role in MS is not clear. The present research is focused on the response of peripheral blood mononuclear cells (PBMCs) to oxidative stress and to the involvement of HSP70-2 (a protein coded by the HSPA1B gene, located in the MHC class III). To this aim, we challenged PBMCs from MS patients and healthy controls with hydrogen peroxide. Specifically, PBMCs mitochondrial activity, HSP70-2 protein expression and the production of intracellular reactive oxygen species were assessed. These parameters were also related to the HSP70-2 rs1061581 polymorphism, which is linked to the risk of developing MS. Moreover, mitochondrial activity and HSP70-2 protein levels were also related to disease severity. Overall, our results indicate that PBMCs, from both MS patients and healthy controls, may display a similar response towards an oxidative insult; within this context, HSP70-2 does not seem to be central in the protection of PBMCs. Nevertheless, the HSP70-2 rs1061581 polymorphism is related to ROS levels and appears to have a role in the different expression of HSP70-2 under oxidative stimulus.

Structure-function relationship of H2A-H2B specific plant histone chaperones Abstract Studies on chromatin structure and function have gained a revived popularity. Histone chaperones are significant players in chromatin organization. They play a significant role in vital nuclear functions like transcription, DNA replication, DNA repair, DNA recombination, and epigenetic regulation, primarily by aiding processes such as histone shuttling and nucleosome assembly/disassembly. Like the other eukaryotes, plants also have a highly orchestrated and dynamic chromatin organization. Plants seem to have more isoforms within the same family of histone chaperones, as compared with other organisms. As some of these are specific to plants, they must have evolved to perform functions unique to plants. However, it appears that only little effort has gone into understanding the structural features of plant histone chaperones and their structure-function relationships. Studies on plant histone chaperones are essential for understanding their role in plant chromatin organization and how plants respond during stress conditions. This review is on the structural and functional aspects of plant histone chaperone families, specifically those which bind to H2A-H2B, viz nucleosome assembly protein (NAP), nucleoplasmin (NPM), and facilitates chromatin transcription (FACT). Here, we also present comparative analyses of these plant histone chaperones with available histone chaperone structures. The review hopes to incite interest among researchers to pursue further research in the area of plant chromatin and the associated histone chaperones.

Identification of an inositol-3-phosphate synthase 1-B gene ( AccIPS1-B ) from Apis cerana cerana and its role in abiotic stress Abstract Inositol phosphate synthase (IPS) is a rate-limiting enzyme in myo-inositol biosynthesis, which can regulate stress responses in plants and animals. However, there are few studies on the function of IPS in insects, especially in Apis cerana cerana. In this study, the inositol-3-phosphate synthase 1-B gene (AccIPS1-B) was isolated from Apis cerana cerana, and its connection to antioxidant defence was investigated. The open reading frame of AccIPS1-B was 1542 bp, encoding a 513 amino acid polypeptide. Quantitative real-time PCR analysis revealed that the expression level of AccIPS1-B was highest in pupae of Apis cerana cerana, and it was expressed at higher levels in the thorax than in other tissues tested. Moreover, the expression of AccIPS1-B was significantly upregulated by abiotic stresses. The recombinant AccIPS1-B also displayed significant tolerance to cumene hydroperoxide and HgCl2. In addition, knockdown of AccIPS1-B significantly suppressed the expression of most of the antioxidant genes and decreased the antioxidant enzymatic activities of SOD, POD, and GST. Taken together, these findings indicate that AccIPS1-B may be involved in the response to antioxidant defence and development in Apis cerana cerana.

Co-expression of CCT subunits hints at TRiC assembly Abstract The eukaryotic cytosolic chaperonin, t-complex polypeptide 1 (TCP-1) ring complex or TRiC, is responsible for folding a tenth of the proteins in the cell. TRiC is a double-ringed barrel with each ring composed of eight different CCT (chaperonin containing TCP-1) subunits. In order for the subunits to assemble together into mature TRiC, which is believed to contain one and only one of each of these subunits per ring, they must be translated from different chromosomes, correctly folded and assembled. When expressed alone in Escherichia coli, the subunits CCT4 and CCT5, interestingly, form TRiC-like homo-oligomeric rings. To explore potential subunit-subunit interactions, we co-expressed these homo-oligomerizing CCT4 and CCT5 subunits or the archaeal chaperonin Mm-Cpn (Methanococcus maripaludis chaperonin) with CCT1-8, one at a time. We found that CCT5 shifted all of the CCT subunits, with the exception of CCT6, into double-barrel TRiC-like complexes, while CCT4 only interacted with CCT5 and CCT8 to form chaperonin rings. We hypothesize that these specific interactions may be due to the formation of hetero-oligomers in E. coli, although more work is needed for validation. We also observed the interaction of CCT5 and Mm-Cpn with smaller fragments of the CCT subunits, confirming their intrinsic chaperone activity. Based on this hetero-oligomer data, we propose that TRiC assembly relies on subunit exchange with some stable homo-oligomers, possibly CCT5, as base assembly units. Eventually, analysis of CCT arrangement in various tissues and at different developmental times is anticipated to provide additional insight on TRiC assembly and CCT subunit composition.