Heat tolerance of a tropical-subtropical rainforest tree species Polyscias elegans: time-dependent dynamic responses of physiological thermostability and biochemistry.

Heat stress interrupts physiological thermostability and triggers biochemical responses that are essential for plant survival. However, there is limited knowledge on the speed plants adjust to heat in hours and days, and which adjustments are crucial. Tropical-subtropical rainforest tree species (Polyscias elegans) were heated at 40°C for 5 d, before returning to 25°C for 13 d of recovery. Leaf heat tolerance was quantified using the temperature at which minimal chl a fluorescence sharply rose (Tcrit ). Tcrit , metabolites, heat shock protein (HSP) abundance and membrane lipid fatty acid (FA) composition were quantified. Tcrit increased by 4°C (48-52°C) within 2 h of 40°C exposure, along with rapid accumulation of metabolites and HSPs. By contrast, it took > 2 d for FA composition to change. At least 2 d were required for Tcrit , HSP90, HSP70 and FAs to return to prestress levels. The results highlight the multi-faceted response of P. elegans to heat stress, and how this response varies over the scale of hours to days, culminating in an increased level of photosynthetic heat tolerance. These responses are important for survival of plants when confronted with heat waves amidst ongoing global climate change.

An auxin regulated Universal stress protein (TaUSP_3B-1) interacts with TaGolS and provides tolerance under drought stress and ER stress.

A previously identified wheat drought stress responsive Universal stress protein, TaUSP_3B-1 has been found to work in an auxin dependent manner in the plant root tissues in the differentiation zone. We also found a novel interacting partner, TaGolS, which physically interacts with TaUSP_3B-1 and colocalizes in the endoplasmic reticulum. TaGolS is a key enzyme in the RFO (Raffinose oligosaccharides) biosynthesis which is well reported to provide tolerance under water deficit conditions. TaUSP_3B-1 overexpression lines showed an early flowering phenotype under drought stress which might be attributed to the increased levels of AtTPPB and AtTPS transcripts under drought stress. Moreover, at the cellular levels ER stress induced TaUSP_3B-1 transcription and provides tolerance in both adaptive and acute ER stress via less ROS accumulation in the overexpression lines. TaUSP_3B-1 overexpression plants had increased silique numbers and a denser root architecture as compared to the WT plants under drought stress.

Molecular Prediction and Correlation of the Structure and Function of Universal Stress Protein A (UspA) from Salmonella Typhimurium.

Salmonella Typhimurium (ST) is a zoonotic pathogen that can cause gastroenteritis in humans when they consume contaminated food or water. When exposed to various stressors, both from living organisms (biotic) and the environment (abiotic), Salmonella Typhimurium produces Universal Stress Proteins (USPs). These proteins are gaining recognition for their crucial role in bacterial stress resistance and the ability to enter a prolonged state of growth arrest. Additionally, USPs exhibit diverse structures due to the fusion of the USP domain with different catalytic motifs, enabling them to participate in various reactions and cellular activities during stressful conditions. In this particular study, researchers cloned and analyzed the uspA gene obtained from poultry-derived strains of Salmonella Typhimurium. The gene comprises 435 base pairs, encoding a USP family protein consisting of 144 amino acids. Phylogenetic analysis demonstrated a close relationship between the uspA genes of Salmonella Typhimurium and those found in other bacterial species. We used molecular dynamics simulations and 3D structure prediction to ensure that the USPA protein was stable. Furthermore, we also carried out motif search and network analysis of protein-protein interactions. The findings from this study offer valuable insights for the development of inhibitors targeted against Salmonella Typhimurium.

Functional Characterization of Salmonella Typhimurium Encoded YciF, a Domain of Unknown Function (DUF892) Family Protein, and Its Role in Protection during Bile and Oxidative Stress.

YciF (STM14_2092) is a member of the domain of unknown function (DUF892) family. It is an uncharacterized protein involved in stress responses in Salmonella Typhimurium. In this study, we investigated the significance of YciF and its DUF892 domain during bile and oxidative stress responses of S. Typhimurium. Purified wild-type YciF forms higher order oligomers, binds to iron, and displays ferroxidase activity. Studies on the site-specific mutants revealed that the ferroxidase activity of YciF is dependent on the two metal binding sites present within the DUF892 domain. Transcriptional analysis displayed that the ΔcspE strain, which has compromised expression of YciF, encounters iron toxicity due to dysregulation of iron homeostasis in the presence of bile. Utilizing this observation, we demonstrate that the bile mediated iron toxicity in ΔcspE causes lethality, primarily through the generation of reactive oxygen species (ROS). Expression of wild-type YciF, but not the three mutants of the DUF892 domain, in ΔcspE alleviate ROS in the presence of bile. Our results establish the role of YciF as a ferroxidase that can sequester excess iron in the cellular milieu to counter ROS-associated cell death. This is the first report of biochemical and functional characterization of a member of the DUF892 family. IMPORTANCE The DUF892 domain has a wide taxonomic distribution encompassing several bacterial pathogens. This domain belongs to the ferritin-like superfamily; however, it has not been biochemically and functionally characterized. This is the first report of characterization of a member of this family. In this study, we demonstrate that S. Typhimurium YciF is an iron binding protein with ferroxidase activity, which is dependent on the metal binding sites present within the DUF892 domain. YciF combats iron toxicity and oxidative damage caused due to exposure to bile. The functional characterization of YciF delineates the significance of the DUF892 domain in bacteria. In addition, our studies on S. Typhimurium bile stress response divulged the importance of comprehensive iron homeostasis and ROS in bacteria.

Identification of universal stress proteins in wheat and functional characterization during abiotic stress.

KEY MESSAGE: TaUSPs are localized in Endoplasmic reticulum and form homo and hetero dimers within themselves. They play significant role in multiple abiotic stress responses in yeast heterologous system and in plants. Universal Stress Proteins are stress responsive proteins present in a variety of life forms ranging from bacteria to multicellular plants and animals. In this study we have identified 85 TaUSP genes in the wheat genome and have characterised their abiotic stress responsive members in yeast under different stress conditions. Localization and Y2H studies suggest that wheat, USP proteins are localized in the ER complex, and extensively crosstalk amongst themselves through forming hetero and homodimers. Expression analysis of these TaUSP genes suggests their role in adaptation to multiple abiotic stresses. TaUSP_5D-1 was found to have some DNA binding activity in yeast. Certain abiotic stress responsive TaUSP genes are found to impart tolerance to temperature stress, oxidative stress, ER stress (DTT treatment) and LiCl2 stress in the yeast heterologous system. TaUSP_5D-1 overexpression in A. thaliana imparts drought tolerance via better lateral root network in transgenic lines. The TaUSP represents an important repertoire of genes for engineering abiotic stress responsiveness in crop plants.

Acute Changes in Myocardial Expression of Heat Shock Proteins and Apoptotic Response Following Blood, delNido, or Custodiol Cardioplegia in Infants Undergoing Open-Heart Surgery.

Stress caused by cardioplegic ischemic arrest was shown to alter the expression levels of heat shock proteins (Hsp), but little is known about their effects, particularly on pediatric hearts. This study aimed to investigate whether myocardial cellular stress and apoptotic response changes due to different cardioplegia (CP) solutions during cardiopulmonary bypass (CPB) in infants and to determine their influence on surgical/clinical outcomes. Therefore, twenty-seven infants for surgical closure of ventricular septal defect were randomly assigned to a CP solution: normothermic blood (BCP), delNido (dNCP), and Custodiol (CCP). Hsp levels and apoptosis were determined by immunoblotting in cardiac tissue from the right atrium before and after CP, and their correlations with cardiac parameters were evaluated. No significant change was observed in Hsp27 levels. Hsp60, Hsp70, and Hsp90 levels decreased significantly in the BCP-group but increased markedly in the CCP-group. Decreased Hsp60 and increased Hsp70 expression were detected in dNCP-group. Importantly, apoptosis was not observed in dNCP- and CCP-groups, whereas marked increases in cleaved caspase-3 and -8 were determined after BCP. Serum cardiac troponin-I (cTn-I), myocardial injury marker, was markedly lower in the BCP- and dNCP-groups than CCP. Additionally, Hsp60, Hsp70, and Hsp90 levels were positively correlated with aortic cross-clamp time, total perfusion time, and cTn-I release. Our findings show that dNCP provides the most effective myocardial preservation in pediatric open-heart surgery and indicate that an increase in Hsp70 expression may be associated with a cardioprotective effect, while an increase in Hsp60 and Hsp90 levels may be an indicator of myocardial damage during CPB.

Hemp-Derived Nanovesicles Protect Leaky Gut and Liver Injury in Dextran Sodium Sulfate-Induced Colitis.

Hemp (Cannabis sativa L.) is used for medicinal purposes owing to its anti-inflammatory and antioxidant activities. We evaluated the protective effect of nanovesicles isolated from hemp plant parts (root, seed, hemp sprout, and leaf) in dextran sulfate sodium (DSS)-induced colitis in mice. The particle sizes of root-derived nanovesicles (RNVs), seed-derived nanovesicles (SNVs), hemp sprout-derived nanovesicles (HSNVs), and leaf-derived nanovesicles (LNVs) were within the range of 100-200 nm as measured by nanoparticle tracking analysis. Acute colitis was induced in C57BL/N mice by 5% DSS in water provided for 7 days. RNVs were administered orally once a day, leading to the recovery of both the small intestine and colon lengths. RNVs, SNVs, and HSNVs restored the tight (ZO-1, claudin-4, occludin) and adherent junctions (E-cadherin and α-tubulin) in DSS-induced small intestine and colon injury. Additionally, RNVs markedly reduced NF-κB activation and oxidative stress proteins in DSS-induced small intestine and colon injury. Tight junction protein expression and epithelial cell permeability were elevated in RNV-, SNV-, and HSNV-treated T84 colon cells exposed to 2% DSS. Interestedly, RNVs, SNVs, HSNVs, and LNVs reduced ALT activity and liver regeneration marker proteins in DSS-induced liver injury. These results showed for the first time that hemp-derived nanovesicles (HNVs) exhibited a protective effect on DSS-induced gut leaky and liver injury through the gut-liver axis by inhibiting oxidative stress marker proteins.

Garlic (Allium sativum) and Fu-ling (Poria cocos) mitigate lead toxicity by improving antioxidant defense mechanisms and chelating ability in the liver of grass carp (Ctenopharyngodon idella).

The heavy metal lead (Pb) is a contaminant widely distributed in the food chain. In this study, eight weeks of feeding containing Garlic (Allium sativum) or Fu-ling (Poria cocos) or both, markedly increased the growth index, enzyme activity, and serum index and significantly decreased muscle Pb level in grass carp (Ctenopharyngodon idella). Upon Pb exposure, the feeding Garlic or Fu-ling or both possessed the similar effects on improving the function of the antioxidant system and chelating ability. Further, the gene expressions of metal binding proteins (TF and MT-2) in the liver of the three experimental groups were significantly higher than those of the control group, which were all highly up-regulated after Pb exposure. At the same time, the activities of antioxidant enzymes (SOD and CAT) and the content of non-enzymatic substance (GSH) in the liver of the Garlic group, Fu-ling group and mixed group were stable compared to the control group after Pb exposure. Moreover, the reduction of Pb toxicity was manifested by the decrease of Pb content in the muscle, and the stable expression of heat stress proteins (HSP30 and HSP60) and immune-related genes (TNF-α and IL-1ß). Taken together, the study preliminarily shows that the Garlic and Fu-ling play a role in mitigating the toxicity of Pb in grass carp.

Subchronic effects of dietary selenium yeast and selenite on growth performance and the immune and antioxidant systems in Nile tilapia Oreochromis niloticus.

Selenium is an essential element but toxic at high levels in animals. The effects of Se on growth performance and the immune system in Nile tilapia remain inconclusive. In this study, Nile tilapia Oreochromis niloticus was fed on selenium yeast (Se(Y))- and selenite (Se(IV))-enriched feed at 0, 3, 6, and 12 µg/g (dry wt) for 45 and 90 d. The growth, bioaccumulation, biochemical markers related to antioxidant, immunological, nervous and digestive systems were evaluated in various fish tissues (liver, intestine, kidney, muscle, brain, spleen, gills). The results showed that the accumulation of Se(Y) was 1.3-2 folds of Se(IV) in most tissues. The growth of tilapia was enhanced by both Se(Y) and Se(IV) at 3 µg/g after 90 d, with Se(Y) better than Se(IV) in tilapia feed. After 45 d, the levels of lipid peroxidation, the activity of the antioxidant enzymes, and the transcriptional levels of the immune related genes (IL-1ß, IFN-γ and TNF-α) and stress proteins (HSP70 and MT) were enhanced in all treatments, except that of MT in the 12 µg/g Se(Y) group. In addition, both Se species inhibited the activity of acetylcholinesterase (AChE) in the brain and one digestive enzyme α-glucosidase (α-Glu) in the intestine at 12 µg/g. However, after 90 d, the effects on most biochemical markers were less pronounced, implying a possible acclimation after prolonged duration. The results demonstrate Se is beneficial to O. niloticus at low levels and toxic at elevated levels. The immunostimulation by Se might be greatly weakened after long term feeding Se-enriched feed. This study helps to better understand the effects of Se on the antioxidant and immune systems and to establish the optimal Se levels in the feed and duration for O. niloticus.

Modulation of antioxidant gene expressions by Roundup® exposure in the decapod Macrobrachium potiuna.

Glyphosate-based herbicides (GBH), including Roundup®, are the most used herbicides in agricultural and non-agricultural areas, which can reach aquatic environments through drift during application or surface runoff. Some studies, mostly in fish, demonstrated that GBH caused oxidative stress in non-target animals. However, only few information is available on the GBH effects in the antioxidant and stress proteins of many other organisms, such as freshwater crustaceans. Thus, we aimed to investigate the effects of environmentally relevant GBH concentrations on the relative transcript expression (RTE) of the superoxide dismutase (sod1), catalase (cat), selenium-dependent glutathione peroxidase (gpx), glutathione-S-transferase (gst), thioredoxin (txn), heat shock protein (hsp70 and hsp90) in the hepatopancreas of the ecologically important freshwater prawn Macrobrachium potiuna. Moreover, this study aimed to assess the gender-differences responses to GBH exposure. Male and female prawns were exposed to three Roundup WG® concentrations (0.0065, 0.065 and 0.28 mg of glyphosate/L) and a control group (0.0 mg/L) for 7 and 14 days. In general, males had an under-expression of the studied genes, indicating an oxidative stress and possible accumulation of ROS in the hepatopancreas. In the opposite, females had an overexpression of the same genes, indicating a more robust antioxidant system, in order to cope with the possible ROS increase after Roundup WG® exposure. Therefore, results confirmed that gender could be a confounding factor in ecotoxicological assessment of GBH effects. Additionally, this work highlights that sod1, cat, gpx, gst, txn, hsp70 and hsp90 gene expressions seem to be useful biomarkers to investigate the oxidative stress caused by Roundup WG® in Macrobrachium sp.

Vimentin is required for normal accumulation of body fat.

Intermediate filaments (nanofilaments) have many functions, especially in response to cellular stress. Mice lacking vimentin (Vim-/-) display phenotypes reflecting reduced levels of cell activation and ability to counteract stress, for example, decreased reactivity of astrocytes after neurotrauma, decreased migration of astrocytes and fibroblasts, attenuated inflammation and fibrosis in lung injury, delayed wound healing, impaired vascular adaptation to nephrectomy, impaired transendothelial migration of lymphocytes and attenuated atherosclerosis. To address the role of vimentin in fat accumulation, we assessed the body weight and fat by dual-energy X-ray absorptiometry (DEXA) in Vim-/- and matched wildtype (WT) mice. While the weight of 1.5-month-old Vim-/- and WT mice was comparable, Vim-/- mice showed decreased body weight at 3.5, 5.5 and 8.5 months (males by 19-22%, females by 18-29%). At 8.5 months, Vim-/- males and females had less body fat compared to WT mice (a decrease by 24%, p < 0.05, and 33%, p < 0.0001, respectively). The body mass index in 8.5 months old Vim-/- mice was lower in males (6.8 vs. 7.8, p < 0.005) and females (6.0 vs. 7.7, p < 0.0001) despite the slightly lower body length of Vim-/- mice. Increased mortality was observed in adult Vim-/- males. We conclude that vimentin is required for the normal accumulation of body fat.

A proteomic-based approach to study underlying molecular responses of the small intestine of Wistar rats to genetically modified corn (MON810).

A genetically modified (GM) commercial corn variety, MON810, resistant to European corn borer, has been shown to be non-toxic to mammals in a number of rodent feeding studies carried out in accordance with OECD Guidelines. Insect resistance results from expression of the Cry1Ab gene encoding an insecticidal Bt protein that causes lysis and cell death in susceptible insect larvae by binding to midgut epithelial cells, which is a key determinant of Cry toxin species specificity. Whilst whole animal studies are still recognised as the 'gold standard' for safety assessment, they only provide indirect evidence for changes at the cellular/organ/tissue level. In contrast, omics-based technologies enable mechanistic understanding of toxicological or nutritional events at the cellular/receptor level. To address this important knowledge-gap and to gain insights into the underlying molecular responses in rat to MON810, differential gene expression in the epithelial cells of the small intestine of rats fed formulated diets containing MON810, its near isogenic line, two conventional corn varieties, and a commercial (Purina™) corn-based control diet were investigated using comparative proteomic profiling. Pairwise and five-way comparisons showed that the majority of proteins that were differentially expressed in the small intestine epithelial cells in response to consumption of the different diets in both 7-day and 28-day studies were related to lipid and carbohydrate metabolism and protein biosynthesis. Irrespective of the diet, a limited number of stress-related proteins were shown to be differentially expressed. However these stress-related proteins differed between diets. No adverse clinical or behavioural effects, or biomarkers of adverse health, were observed in rats fed GM corn compared to the other corn diets. These findings suggest that MON810 has negligible effects on the small intestine of rats at the cellular level compared with the well-documented toxicity observed in susceptible insects.

Immune response of juvenile common carp (Cyprinus carpio L.) exposed to a mixture of sewage chemicals.

Pharmaceuticals and household chemicals are important components of municipal sewage. Many of them are biologically active, disrupting not only hormonal regulation of aquatic animals but also, indirectly, disturbing their immunological protection. In the environment, chemicals rarely act as individual substances, but as elements of mixtures. Therefore, the aim of this study was to check whether the acute laboratory exposure of common carp juveniles to a mixture of ibuprofen, sodium dodecyl sulphate (SDS), dimethyl sulfoxide (DMSO) and 17 α-ethynylestradiol in increasing concentrations, modifies the levels of innate immunity (lysozyme, C-reactive protein) as well as general stress (metallothioneins, heat shock proteins HSP70) markers in brain, liver, gills, spleen and mucus. The levels of the markers were measured by an immunodetection technique. Not only do the pharmaceuticals and household chemicals impair immunological reactions of young carp in various tissues but also do that in a concentration-dependent manner in the liver, gills, spleen and mucus. This has a very important implication, since it may result in higher sensitivity of young fish to pathogens due to energy allocation to defence processes. The comparisons of the pattern of stress reactions in the studied organ samples indicated that mucus appeared to be a good, non-invasive material for monitoring of environmental state and fish conditions.

Transgenerational and multigenerational stress gene responses to the insecticide etofenprox in Folsomia candida (Collembola).

Insecticide exposure may cause both transgenerational and multigenerational effects on populations, but the molecular mechanisms of these changes remain largely unclear. Many studies have focused on either transgenerational or multigenerational mechanisms but did neglect the comparative aspects. This study assessed whether the pyrethroid insecticide etofenprox (formulation Trebon® 30 EC) shows transgenerational and/or multigenerational effects on the survival and reproduction of Folsomia candida (Collembola). The activation of stress-related genes was studied to detect whether etofenprox modifies the expression of reproduction-associated genes in trans- and multigenerational treatments. A laboratory study was carried out for three generations with five insecticide concentrations in LUFA 2.2 soil. In the transgenerational treatment, only the parent generation (P) was exposed, but the subsequent generations were not. In the multigenerational treatment, all three generations were exposed to the insecticide in the same manner. Multigenerational exposure resulted in reduced reproduction effects over generations, suggesting that F. candida is capable of acclimating to enhanced concentration levels of etofenprox during prolonged exposure over multiple generations. In the transgenerational treatment, the heat shock protein 70 was up-regulated and cytochrome oxidase 6N4v1 expression down-regulated in a dose-dependent manner in the F2 generation. This finding raises the possibility of the epigenetic inheritance of insecticide impacts on parents. Furthermore, CYP6N4v1 expression was oppositely regulated in the trans- and multigenerational treatments. Our results draw attention to the differences in molecular level responses of F. candida to trans- and multigenerational etofenprox exposure.

Heat Shock Proteins Are Essential Components in Transformation and Tumor Progression: Cancer Cell Intrinsic Pathways and Beyond.

Heat shock protein (HSP) synthesis is switched on in a remarkably wide range of tumor cells, in both experimental animal systems and in human cancer, in which these proteins accumulate in high levels. In each case, elevated HSP concentrations bode ill for the patient, and are associated with a poor outlook in terms of survival in most cancer types. The significance of elevated HSPs is underpinned by their essential roles in mediating tumor cell intrinsic traits such as unscheduled cell division, escape from programmed cell death and senescence, de novo angiogenesis, and increased invasion and metastasis. An increased HSP expression thus seems essential for tumorigenesis. Perhaps of equal significance is the pronounced interplay between cancer cells and the tumor milieu, with essential roles for intracellular HSPs in the properties of the stromal cells, and their roles in programming malignant cells and in the release of HSPs from cancer cells to influence the behavior of the adjacent tumor and infiltrating the normal cells. These findings of a triple role for elevated HSP expression in tumorigenesis strongly support the targeting of HSPs in cancer, especially given the role of such stress proteins in resistance to conventional therapies.

The Potential Functions of Small Heat Shock Proteins in the Uterine Musculature during Pregnancy.

The small heat shock protein B (HSPB) family is comprised of eleven members with many being induced by physiological stressors. In addition to being molecular chaperones, it is clear these proteins also play important roles in cell death regulation, cytoskeletal rearrangements, and immune system activation. These processes are important for the uterine smooth muscle or myometrium during pregnancy as it changes from a quiescent tissue, during the majority of pregnancy, to a powerful and contractile tissue at labor. The initiation and progression of labor within the myometrium also appears to require an inflammatory response as it is infiltrated by immune cells and it produces pro-inflammatory mediators. This chapter summarizes current knowledge on the expression of HSPB family members in the myometrium during pregnancy and speculates on the possible roles of these proteins during myometrial programming and transformation of the myometrium into a possible immune regulatory tissue.

Acute and long-term effects of blood flow restricted training on heat shock proteins and endogenous antioxidant systems.

Blood flow restricted exercise (BFRE) with low loads has been demonstrated to induce considerable stress to exercising muscles. Muscle cells have developed a series of defensive systems against exercise-induced stress. However, little is known about acute and long-term effects of BFRE training on these systems. Nine previously untrained females trained low-load BFRE and heavy load strength training (HLS) on separate legs and on separate days to investigate acute and long-term effects on heat shock proteins (HSP) and endogenous antioxidant systems in skeletal muscles. BFRE and HLS increased muscle strength similarly by 12 ± 7% and 12 ± 6%, respectively, after 12 weeks of training. Acutely after the first BFRE and HLS exercise session, αB-crystallin and HSP27 content increased in cytoskeletal structures, accompanied by increased expression of several HSP genes. After 12 weeks of training, this acute HSP response was absent. Basal levels of αB-crystallin, HSP27, HSP70, mnSOD, or GPx1 remained unchanged after 12 weeks of training, but HSP27 levels increased in the cytoskeleton. Marked translocation of HSP to cytoskeletal structures at the commencement of training indicates that these structures are highly stressed from BFRE and HLS. However, as the muscle gets used to this type of exercise, this response is abolished.

Short-term molecular and physiological responses to heat stress in neritic copepods Acartia tonsa and Eurytemora affinis.

Invertebrates inhabiting shallow water habitats represent particularly appropriate organisms for studying the acclimation potential to environmental stress, since they naturally experience large fluctuations in key abiotic factors such as temperature and salinity. We quantified the biochemical- (mRNA transcripts of 78-kDa glucose-regulated protein (grp78), 70-kDa heat shock protein (hsp70), 90-kDa heat shock protein (hsp90), protein synthesis of HSP70) and organismal- (oxygen consumption rates) level responses to acute heat stress on two neritic copepods (Acartia tonsa and Eurytemora affinis) with special emphasis on the role of short-term acclimation. Transcripts of hsp increased with increasing acute temperature exposure and protein quantities (HSP70) were detectable for 30h. In A. tonsa, HSP70 synthesis was also associated with handling stress. In E. affinis, heat-dependent responses were detected in hsp90, grp78 (mRNA) and HSP70 (protein) expression. Acclimation to a warmer temperature significantly decreased the heat stress response in both species. In A. tonsa, short-term acclimation to heat was not detected at the organismal level via metabolic rate. This study reveals interspecific differences in both the gene expression of stress molecules (e.g. hsp90) as well as the stress factors needed to evoke a stress response (heat vs. handling). We demonstrate that cellular stress markers can be useful measures of short-term thermal acclimation in copepods, which may remain undetected by organismal-level measures.

Weight loss-induced stress in subcutaneous adipose tissue is related to weight regain.

Initial successful weight loss is often followed by weight regain after the dietary intervention. Compared with lean people, cellular stress in adipose tissue is increased in obese subjects. However, the relation between cellular stress and the risk for weight regain after weight loss is unclear. Therefore, we determined the expression levels of stress proteins during weight loss and weight maintenance in relation to weight regain. In vivo findings were compared with results from in vitro cultured human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes. In total, eighteen healthy subjects underwent an 8-week diet programme with a 10-month follow-up. Participants were categorised as weight maintainers or weight regainers (WR) depending on their weight changes during the intervention. Abdominal subcutaneous adipose tissue biopsies were obtained before and after the diet and after the follow-up. In vitro differentiated SGBS adipocytes were starved for 96 h with low (0·55 mm) glucose. Levels of stress proteins were determined by Western blotting. WR showed increased expressions of ß-actin, calnexin, heat shock protein (HSP) 27, HSP60 and HSP70. Changes of ß-actin, HSP27 and HSP70 are linked to HSP60, a proposed key factor in weight regain after weight loss. SGBS adipocytes showed increased levels of ß-actin and HSP60 after 96 h of glucose restriction. The increased level of cellular stress proteins in the adipose tissue of WR probably resides in the adipocytes as shown by in vitro experiments. Cellular stress accumulated in adipose tissue during weight loss may be a risk factor for weight regain.

Heat shock proteins in the kidney.

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