The expression and function of hsp30-like small heat shock protein genes in amphibians, birds, fish, and reptiles

A rapid return to normal: temporal gene expression patterns following cold exposure in the bumble bee Bombus impatiens

Bumble bees are common in cooler climates and many species likely experience periodic exposure to very cold temperatures, but little is known about the temporal dynamics of cold response mechanisms following chill exposure, especially how persistent effects of cold exposure may facilitate tolerance of future events. To investigate molecular processes involved in the temporal response by bumble bees to acute cold exposure, we compared mRNA transcript abundance in Bombus impatiens workers exposed to 0°C for 75 min (inducing chill coma) and control bees maintained at a constant ambient temperature (28°C). We sequenced the 3' end of mRNA transcripts (TagSeq) to quantify gene expression in thoracic tissue of bees at several time points (0, 10, 30, 120 and 720 min) following cold exposure. Significant differences from control bees were only detectable within 30 min after the treatment, with most occurring at the 10 min recovery time point. Genes associated with gluconeogenesis and glycolysis were most notably upregulated, while genes related to lipid and purine metabolism were downregulated. The observed patterns of expression indicate a rapid recovery after chill coma, suggesting an acute differential transcriptional response during recovery from chill coma and return to baseline expression levels within an hour, with no long-term gene expression markers of this cold exposure. Our work highlights the functions and pathways important for acute cold recovery, provides an estimated time frame for recovery from cold exposure in bumble bees, and suggests that cold hardening may be less important for these heterothermic insects.

Environmental factors influence cross-talk between a heat shock protein and an oxidative stress protein modification in the lizard Gallotia galloti

Better understanding how organisms respond to their abiotic environment, especially at the biochemical level, is critical in predicting population trajectories under climate change. In this study, we measured constitutive stress biomarkers and protein post-translational modifications associated with oxidative stress in Gallotia galloti, an insular lizard species inhabiting highly heterogeneous environments on Tenerife. Tenerife is a small volcanic island in a relatively isolated archipelago off the West coast of Africa. We found that expression of GRP94, a molecular chaperone protein, and levels of protein carbonylation, a marker of cellular stress, change across different environments, depending on solar radiation-related variables and topology. Here, we report in a wild animal population, cross-talk between the baseline levels of the heat shock protein-like GRP94 and oxidative damage (protein carbonylation), which are influenced by a range of available temperatures, quantified through modelled operative temperature. This suggests a dynamic trade-off between cellular homeostasis and oxidative damage in lizards adapted to this thermally and topologically heterogeneous environment.

Molecular evolution of the heat shock protein family and the role of HSP30 in immune response and wound healing in lampreys (Lethenteron reissneri)

Heat shock proteins (HSPs) are molecular chaperones that ubiquitously exist in various organisms and play essential roles in protein folding, transport, and expression. While most HSPs are highly conserved across species, a few HSPs are evolutionarily distinct in some species and may have unique functions. To explore the evolutionary history of the vertebrate HSP family, we identify members of the HSP family at the genome-wide level in lampreys (Lethenteron reissneri), a living representative of jawless vertebrates diverged from jawed vertebrates over 500 million years ago. The phylogenetic analysis reveals that the lamprey HSP family contains HSP90a1, HSP90a2, HSC70, HSP60, HSP30, HSP27, HSP17, and HSP10, which have a primitive status in the molecular evolution of vertebrate HSPs. Transcriptome analysis reveals the expression distribution of members of the HSP family in various tissues of lampreys. It is shown that HSP30, normally found in birds, amphibians, and fish, is also present in lampreys, with remarkable expansion of HSP30 gene copies in the lamprey genome. The transcription of HSP30 is significantly induced in leukocytes and heart of lampreys during various pathogens or poly(I:C) stimulation, indicating that HSP30 may be involved in the immune defense of lampreys in response to bacterial or viral infection. Immunohistochemistry demonstrates significantly increased HSP30 expression in subcutaneous muscle tissue after skin injury in lamprey models of wound repair. Furthermore, transcriptome analysis shows that ectopic expression of HSP30 in 3T3-L1 fibroblasts affect the expression of genes related to the PI3K-AKT signaling pathway, suggesting that HSP30 could serves as a negative regulator of fibrosis. These results indicate that HSP30 may play a critical role in facilitating the process of lamprey skin repair following injury. This study provides new insights into the origin and evolution of the HSP gene family in vertebrates and offers valuable clues to reveal the important role of HSP30 in immune defense and wound healing of lampreys.

HSPB11 is a Prognostic Biomarker Associated with Immune Infiltrates in Hepatocellular Carcinoma

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Patients and Methods

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Small Heat Shock Protein's Gene Expression Response to Iron Oxide Nanoparticles in the Brain

Small heat shock proteins (SHSPs) are conserved proteins that participate in many cellular functions like preventing protein aggregation and stress response. However, their role in responding to nanoparticles (NPs) has not yet been explained. We used a chicken embryo model to investigate the effects of two different forms of iron oxide-NPs (IONPs) on the mRNA expression of HSPB1, HSPB5, HSPB8, and HSPB9 in cerebral tissue. Two hundred-ten fertilized eggs were randomly divided into seven groups (30 eggs/group; 10 eggs/replicate). Three groups received 100 ppm, 250 ppm, and 500 ppm of Fe2O3-NPs, respectively. Three other groups received 100 ppm, 250 ppm, and 500 ppm of Fe3O4-NPs, respectively, and one group remained untreated as a control. The NPs were given by in ovo method (0.3 ml/egg) only once on the first day of the embryonic period. Samples from cerebrums were collected on day 20 for gene expression analyses. HSPB1, HSPB5, HSPB8, and HSPB9 were all expressed in both normal and IONPs exposed cerebrums. SHSPs tested were differentially expressed in response to various concentrations of IONPs. The highest expression levels in response to Fe2O3-NPs and Fe3O4-NPs were observed for HSPB5 and HSPB9, respectively. The greatest gene expression changes due to the Fe2O3-NPs and Fe3O4-NPs exposure observed for HSPB1 and HSPB5, respectively. The results suggest a protective cellular mechanism against IONPs through SHSPs and recommend that expression profiling of SHSPs be included in the study of nanotoxicity.

Transcriptome Responses of Atlantic Salmon (Salmo salar L.) to Viral and Bacterial Pathogens, Inflammation, and Stress

Transcriptomics provides valuable data for functional annotations of genes, the discovery of biomarkers, and quantitative assessment of responses to challenges. Meta-analysis of Nofima’s Atlantic salmon microarray database was performed for the selection of genes that have shown strong and reproducible expression changes. Using data from 127 experiments including 6440 microarrays, four transcription modules (TM) were identified with a total of 902 annotated genes: 161 virus responsive genes – VRG (activated with five viruses and poly I:C), genes that responded to three pathogenic bacteria (523 up and 33 down-regulated genes), inflammation not caused by infections – wounds, melanized foci in skeletal muscle and exposure to PAMP (180 up and 72 down-regulated genes), and stress by exercise, crowding and cortisol implants (33 genes). To assist the selection of gene markers, genes in each TM were ranked according to the scale of expression changes. In terms of functional annotations, association with diseases and stress was unknown or not reflected in public databases for a large part of genes, including several genes with the highest ranks. A set of multifunctional genes was discovered. Cholesterol 25-hydroxylase was present in all TM and 22 genes, including most differentially expressed matrix metalloproteinases 9 and 13 were assigned to three TMs. The meta-analysis has improved understanding of the defense strategies in Atlantic salmon. VRG have demonstrated equal or similar responses to RNA (SAV, IPNV, PRV, and ISAV), and DNA (gill pox) viruses, injection of bacterial DNA (plasmid) and exposure of cells to PAMP (CpG and gardiquimod) and relatively low sensitivity to inflammation and bacteria. Genes of the highest rank show preferential expression in erythrocytes. This group includes multigene families (gig and several trim families) and many paralogs. Of pathogen recognition receptors, only RNA helicases have shown strong expression changes. Most VRG (82%) are effectors with a preponderance of ubiquitin-related genes, GTPases, and genes of nucleotide metabolism. Many VRG have unknown roles. The identification of TMs makes possible quantification of responses and assessment of their interactions. Based on this, we are able to separate pathogen-specific responses from general inflammation and stress.

Molecular adaptations to heat stress in the thermophilic ant genus Cataglyphis

Over the last decade, increasing attention has been paid to the molecular adaptations used by organisms to cope with thermal stress. However, to date, few studies have focused on thermophilic species living in hot, arid climates. In this study, we explored molecular adaptations to heat stress in the thermophilic ant genus Cataglyphis, one of the world's most thermotolerant animal taxa. We compared heat tolerance and gene expression patterns across six Cataglyphis species from distinct phylogenetic groups that live in different habitats and experience different thermal regimes. We found that all six species had high heat tolerance levels with critical thermal maxima (CT_max ) ranging from 43℃ to 45℃ and a median lethal temperature (LT50) ranging from 44.5℃ to 46.8℃. Transcriptome analyses revealed that, although the number of differentially expressed genes varied widely for the six species (from 54 to 1118), many were also shared. Functional annotation of the differentially expressed and co-expressed genes showed that the biological pathways involved in heat-shock responses were similar among species and were associated with four major processes: the regulation of transcriptional machinery and DNA metabolism; the preservation of proteome stability; the elimination of toxic residues; and the maintenance of cellular integrity. Overall, our results suggest that molecular responses to heat stress have been evolutionarily conserved in the ant genus Cataglyphis and that their diversity may help workers withstand temperatures close to their physiological limits.

Molecular characterization, expression and functional analysis of TGFβ1-b in crucian carp (Carassius carassius)

Transforming growth factor β1 (TGFβ1) is a polyfunctional cytokine with important roles in growth, differentiation and immune function in various animals. In this study, PCR, bioinformatics, real-time quantitative PCR, prokaryotic expression, protein purification and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-TOF-MS) were applied to investigate the structural features and function of TGFβ1-b in crucian carp. The complete coding sequence (CDS) of TGFβ1-b was 1134 bp in length and was submitted to GenBank (ID: MH473141). TGFβ1-b encoded a putative protein of 377 amino acids and included a signal peptide consisting of 22 amino acids. TGFβ1-b was relatively conservative in fish and distant from mammals in terms of evolutionary relationship. TGFβ1-b was found to be expressed in various tissues, with the highest expression in the kidney. The expressions of TGFβ1-b in muscle, heart and liver were increased with the addition of Rhodopseudomonas palustris, Bacillus subtilis and Enterococcus faecium at 30 days (p < 0.01). While, the expressions of SMAD2, SMAD3 and SMAD7 were also up-regulated with the addition of R. palustris at 20 days (p < 0.01). The expression of TGFβ1-b could be affected by time and group factors (p < 0.05). Moreover, the expression vector TGFβ1-b-pDE2 was successfully constructed. Prokaryotic expression indicated that a 43 kDa target protein was obtained after induction with 1.5 mM isopropyl-beta-D-thiogalactopyranoside (IPTG) for 3.5 h at 37 °C for 200 r/h. The activities of alkaline phosphatase and lysozyme in injection TGFβ1-b protein group (ITg) and feeding broken bacterial liquid group (BTg) were significantly increased at 24 h (p < 0.01). And the activities of superoxide dismutase in ITg were significantly increased at 36 h (p < 0.01). Besides, the expressions of heat shock protein 30 and heat shock protein 47 in ITg and BTg were significantly increased (p < 0.01). Whereas, the expression of interleukin-11 was significantly reduced (p < 0.01). These results indicated that TGFβ1-b protein might play a role in immunity of crucian carp.

Differential expression of small heat shock proteins in the brain of broiler embryo; the effects of embryonic thermal manipulation

Broilers are more vulnerable to high temperatures than mammals due to the feather cover, lack of sweat glands, fast growth and intensive breeding in commercial systems. Thermal stresses affect the function of various organs and change the expression profiles of hundreds of genes in the different tissues of broilers. Thermal manipulation (TM) during embryogenesis can increase heat tolerance in growing broilers. Small heat shock proteins (SHSPs) are a group of HSPs which participate in many cellular functions like response to different stressors. However, their role in the thermotolerance has not been fully elucidated. Ninety fertilized eggs were randomly divided into three groups (30 eggs/group; 10 eggs/replicate). Normal control (NC) eggs were incubated at 37.5 °C throughout the incubation period whereas heat stress (HS) and cold stress (CS) groups were kept at 41 °C and 33 °C from 15 to 17th day of incubation for 3 h each day, respectively. On day 20, samples from the cerebrums were harvested for histopathology and mRNA expression analyses of HSPB1, HSPB5, HSPB8, and HSPB9. There were no significant differences in survivability, defected embryos, hatchability, and body weight among treatments. TM had no major deleterious effects on the cerebral tissue except for mild degeneration in the HS group. HSPB1, HSPB5, HSPB8, and HSPB9 were expressed in the presence and absence of TM. All SHSP genes tested were downregulated in response to TM except for HSPB9 which was upregulated in the HS group. The highest change in gene expression due to TM observed for HSPB1. This study presents a broader understanding of mechanisms underlying response to TM in broilers. The results suggest that HSPB1, HSPB5, HSPB8, and HSPB9 are involved in thermotolerance in broilers and SHSPs could be involved in the gene expression profiling of TM. It may propose the use of nutritional supplements in the poultry industry to modulate SHSPs.

The untapped potential of reptile biodiversity for understanding how and why animals age

1. The field of comparative aging biology has greatly expanded in the past 20 years. Longitudinal studies of populations of reptiles with a range of maximum lifespans have accumulated and been analyzed for evidence of mortality senescence and reproductive decline. While not as well represented in studies of amniote senescence, reptiles have been the subjects of many recent demographic and mechanistic studies of the biology of aging. 2. We review recent literature on reptile demographic senescence, mechanisms of senescence, and identify unanswered questions. Given the ecophysiological and demographic diversity of reptiles, what is the expected range of reptile senescence rates? Are known mechanisms of aging in reptiles consistent with canonical hallmarks of aging in model systems? What are the knowledge gaps in our understanding of reptile aging? 3. We find ample evidence of increasing mortality with advancing age in many reptiles. Testudines stand out as slower aging than other orders, but data on crocodilians and tuatara are sparse. Sex-specific analyses are generally not available. Studies of female reproduction suggest that reptiles are less likely to have reproductive decline with advancing age than mammals. 4. Reptiles share many physiological and molecular pathways of aging with mammals, birds, and laboratory model organisms. Adaptations related to stress physiology coupled with reptilian ectothermy suggest novel comparisons and contrasts that can be made with canonical aging phenotypes in mammals. These include stem cell and regeneration biology, homeostatic mechanisms, IIS/TOR signaling, and DNA repair. 5. To overcome challenges to the study of reptile aging, we recommend extending and expanding long-term monitoring of reptile populations, developing reptile cell lines to aid cellular biology, conducting more comparative studies of reptile morphology and physiology sampled along relevant life-history axes, and sequencing more reptile genomes for comparative genomics. Given the diversity of reptile life histories and adaptations, achieving these directives will likely greatly benefit all aging biology.

UGM: a more stable procedure for large-scale multiple testing problems, new solutions to identify oncogene

Variations of gene expression levels play an important role in tumors. There are numerous methods to identify differentially expressed genes in high-throughput sequencing. Several algorithms endeavor to identify distinctive genetic patterns susceptable to particular diseases. Although these processes have been proved successful, the probability that the number of non-differentially expressed genes measured by false discovery rate (FDR) has a large standard deviation, and the misidentification rate (type I error) grows rapidly when the number of genes to be detected become larger. In this study we developed a new method, Unit Gamma Measurement (UGM), accounting for multiple hypotheses test statistics distribution, which could reduce the dependency problem. Simulated expression profile data and breast cancer RNA-Seq data were utilized to testify the accuracy of UGM. The results show that the number of non-differentially expressed genes identified by the UGM is very close to the real-evidence data, and the UGM also has a smaller standard error, range, quartile range and RMS error. In addition, the UGM can be used to screen many breast cancer-associated genes, such as BRCA1, BRCA2, PTEN, BRIP1, etc., provides better accuracy, robustness and efficiency, the method of identification differentially expressed genes in high-throughput sequencing.

HSP70 localization in Podarcissiculus embryos under natural thermal regime and following a non-lethal cold shock

The Heat Shock Proteins (HSPs) are a superfamily of molecular chaperones that maintain cellular homeostasis under stress. HSP70 represents the major stress-inducible family member, often activated in response to changes in thermal ranges of organisms, and therefore playing an important role enhancing thermal tolerance limits in ectothermic animals. The present study aimed to investigate the presence and the localization of HSP70 through the development of Podarcis siculus, an oviparous lizard inhabiting temperate Mediterranean regions, showing a limited potential to tolerate thermal changes during embryogenesis. Immunohistochemical analysis demonstrated that HSP70 protein is constitutively present in early embryonic stages, abundantly distributed in eye, in encephalic domains (predominantly in ventricular areas and in grey matter), in grey matter of spinal cord, in lung, gut mucosa, hepatic cords and kidney tubules. Interestingly, a severe drop in incubation temperature (5°C for 3 days) does not induce enhancements in HSP70 levels nor changes in tissues localization. These results suggest that the HSP70 found in P. siculus embryos represents a non-inducible, constitutive molecular chaperone that should be better called Heat Shock Cognate 70 (HSC70); the presence of stress-induced members of the HSP family in P. siculus has yet to be proven.

Innate-immune responses of tilapia (Oreochromis mossambicus) exposure to acute cold stress

In this present study, Oreochromis mossambicus tilapia were transferred to cold water at 12°C for various time intervals (1, 4, 8, 24, and 48 hr) and its innate immune response was analyzed by studying cellular and humoral parameters. In vivo, alternative complement pathway activity in blood plasma was rapidly increased at 1 hr of cold water (12°C) exposure. Lysozyme activity and cortisol levels of plasma were increased at 4 and 1 hr, respectively. Surprisingly, only plasma cortisol levels remained unchanged through 24 hr of cold water transfer. Phagocytic ability, phagocytic capacity, and respiratory burst (RB) activity of head kidney (HK) leukocytes and splenocytes showed no any significant changes. In peripheral blood leukocytes, phagocytic capacity, and RB activity were increased at 24 hr of cold water exposure. The expressions of genes involved innate immunity in splenocytes and HK leukocytes of tilapia cold water exposure were analyzed, messenger RNA (mRNA) expressions of HSP70, HSP90, and immunoglobulin M failed to change upon exposure to cold stress. Major histocompatibility complex-I and II mRNAs were significantly increased in tilapia splenocytes at 1 hr of cold water transferred. Whereas myxovirus (Mx) expression was increased in splenocytes and HK leukocytes of tilapia after 1 hr of cold water exposed. Our result reveals that the exposure of tilapia to acute cold stress condition significantly enhances plasma acid phosphatase activity and both phagocytic capacity and RB activity. Furthermore, cold stress significantly stimulates Mx gene expression in splenocytes and HK leukocytes.

Deep transcriptome analysis of the heat shock response in an Atlantic sturgeon (Acipenser oxyrinchus) cell line

Despite efforts to restore Atlantic sturgeon in European rivers, aquaculture techniques result in animals with high post-release mortality due to, among other reasons, their low tolerance to increasing water temperature. Marker genes to monitor heat stress are needed in order to identify heat-resistant fish. Therefore, an Atlantic sturgeon cell line was exposed to different heat shock protocols (30 °C and 35 °C) and differences in gene expression were investigated. In total 3020 contigs (∼1.5%) were differentially expressed. As the core of the upregulated contigs corresponded to heat shock proteins (HSP), the heat shock factor (HSF) and the HSP gene families were annotated in Atlantic sturgeon and mapped via Illumina RNA sequencing to identify heat-inducible family members. Up to 6 hsf and 76 hsp genes were identified in the Atlantic sturgeon transcriptome resources, 16 of which were significantly responsive to the applied heat shock. The previously studied hspa1 (hsp70) gene was only significantly upregulated at the highest heat shock (35 °C), while a set of 5 genes (hspc1, hsph3a, hspb1b, hspb11a, and hspb11b) was upregulated at all conditions. Although the hspc1 (hsp90a) gene was previously used as heat shock-marker in sturgeons, we found that hspb11a is the most heat-inducible gene, with up to 3296-fold higher expression in the treated cells, constituting the candidate gene markers for in vivo trials.

Effect of hemin, baicalein and heme oxygenase-1 (HO-1) enzyme activity inhibitors on Cd-induced accumulation of HO-1, HSPs and aggresome-like structures in Xenopus kidney epithelial cells

Cadmium is a highly toxic environmental pollutant that can cause many adverse effects including cancer, neurological disease and kidney damage. Aquatic amphibians are particularly susceptible to this toxicant as it was shown to cause developmental abnormalities and genotoxic effects. In mammalian cells, the accumulation of heme oxygenase-1 (HO-1), which catalyzes the breakdown of heme into CO, free iron and biliverdin, was reported to protect cells against potentially lethal concentrations of CdCl₂. In the present study, CdCl₂ treatment of A6 kidney epithelial cells, derived from the frog, Xenopus laevis, induced the accumulation of HO-1, heat shock protein 70 (HSP70) and HSP30 as well as an increase in the production of aggregated protein and aggresome-like structures. Treatment of cells with inhibitors of HO-1 enzyme activity, tin protoporphyrin (SnPP) and zinc protoporphyrin (ZnPP), enhanced CdCl₂-induced actin cytoskeletal disorganization and the accumulation of HO-1, HSP70, aggregated protein and aggresome-like structures. Treatment of cells with hemin and baicalein, which were previously shown to provide cytoprotection against various stresses, induced HO-1 accumulation in a concentration-dependent manner. Also, treatment of cells with hemin and baicalein suppressed CdCl₂-induced actin dysregulation and the accumulation of aggregated protein and aggresome-like structures. This cytoprotective effect was inhibited by SnPP. These results suggest that HO-1-mediated protection against CdCl₂ toxicity includes the maintenance of actin cytoskeletal and microtubular structure and the suppression of aggregated protein and aggresome-like structures.

Effect of isothiocyanates, BITC and PEITC, on stress protein accumulation, protein aggregation and aggresome-like structure formation in Xenopus A6 kidney epithelial cells

Numerous studies have elucidated the health benefits of organosulfur compounds, known as isothiocyanates (ITCs), derived from cruciferous vegetables. As electrophiles, ITCs have the ability to directly bind and modify thiol-containing compounds such as glutathione and cellular protein, including tubulin. While the biochemical effects of ITCs have been well characterized, less information is available regarding their effects on the accumulation of stress-inducible heme oxygenase-1 (HO-1), heat shock proteins (HSPs) and the possible formation of aggregated protein due to thiol modification. The present study has examined the effect of the ITCs, benzyl isothiocyanate (BITC) and phenethyl isothiocyanate (PEITC), on the accumulation of HO-1, HSP70 and HSP30 in Xenopus laevis A6 kidney epithelial cells. Immunoblot analysis revealed that both BITC and PEITC induced the accumulation of HO-1 and HSP70 whereas HSP30 levels were enhanced only in cells treated with BITC. Immunocytochemistry determined that ITC treatment induced F-actin disorganization and membrane ruffling and enhanced accumulation of HO-1 in the cytoplasm. Additionally, BITC induced enhanced levels of ubiquitinated protein, aggregated protein, and the collapse and fragmentation of microtubules. In comparison, treatment of cells with the proteasomal inhibitor, MG132, induced the accumulation of all three stress proteins, aggregated protein and aggresome-like structures. Finally, cells pretreated with BITC inhibited the formation of MG132-induced aggresome-like structures in the perinuclear region. This latter finding suggests that BITC-induced microtubule fragmentation may impede the movement of aggregated protein via microtubules and their subsequent coalescence into aggresome-like structures in the perinuclear region.

Potential effects of low molecular weight phthalate esters (C16H22O4 and C12H14O4) on the freshwater fish Cyprinus carpio

The aim of the present study is to assess the toxic effect of dibutyl phthalate (DBP) and diethyl phthalate (DEP) on the freshwater fish Cyprinus carpio. The median lethal concentrations of DBP and DEP for 96 h are found to be 35 and 53 mg L-1, respectively. Fish were exposed to 3.5 mg L-1 (Treatment I) and 1.75 mg L-1 (Treatment II) of DBP and 5.3 mg L-1 (Treatment I) and 2.65 mg L-1 (Treatment II) of DEP for a period of 35 days. The DBP and DEP exposed fish show a concentration based toxic effect on the selected parameters of this study. The hematological parameters, such as hemoglobin (Hb), hematocrit (Hct) and erythrocyte (RBC), were found to decrease in the DBP and DEP treated fish, whereas their leucocyte (WBC) count increased compared to that of the control groups. A biphasic response is noted in the erythrocyte indices, such as mean cellular volume (MCV), mean cellular hemoglobin (MCH) and mean cellular hemoglobin concentration (MCHC), throughout the study period. Exposure to DBP and DEP caused a significant (p < 0.05) decrease in sodium (Na+), potassium (K+), and chloride (Cl-) levels in the gill and brain of the fish throughout the study period when compared to that of their respective controls. The plasma protein level decreased in all the treatments, whereas the plasma glucose level significantly increased in the DBP and DEP exposed fish. Maximum inhibition of Na+/K+-ATPase activity was noticed in the gill and brain of the fish exposed to DBP and DEP. The cholinesterase (ChE) activity in the brain of the fish significantly decreased throughout the study period. A significant (p < 0.05) increase in glutamate oxaloacetate transaminase (GOT) and glutamic pyruvate transaminase (GPT) activity was noted in the fish exposed to both toxicants. The antioxidant enzymatic parameters such as superoxide dismutase (SOD) and catalase (CAT) activities were found to decrease in the gill and liver of the DBP and DEP treated fish, whereas a significant (p < 0.05) increase in lipid peroxidation (LPO) was observed. The above mentioned parameters could be used as potential biomarkers in clinical trials for the assessment of plasticizers. This study provides indispensable information towards future research on the effect of plasticizers on non-target organisms including humans.

Loggerhead sea turtle embryos (Caretta caretta) regulate expression of stress response and developmental genes when exposed to a biologically realistic heat stress

Oviparous reptile embryos are expected to breach their critical thermal maxima if temperatures reach those predicted under current climate change models due to the lack of the maternal buffering processes and parental care. Heat-shock proteins (HSPs) are integral in the molecular response to thermal stress, and their expression is heritable, but the roles of other candidate families such as the heat-shock factors (HSFs) have not been determined in reptiles. Here, we subject embryonic sea turtles (Caretta caretta) to a biologically realistic thermal stress and employ de novo transcriptomic profiling of brain tissue to investigate the underlying molecular response. From a reference transcriptome of 302 293 transcripts, 179 were identified as differentially expressed between treatments. As anticipated, genes enriched in the heat-shock treatment were primarily associated with the Hsp families, or were genes whose products play similar protein editing and chaperone functions (e.g. bag3, MYOC and serpinh1). Unexpectedly, genes encoding the HSFs were not significantly upregulated under thermal stress, indicating their presence in unstressed cells in an inactive state. Genes that were downregulated under thermal stress were less well functionally defined but were associated with stress response, development and cellular organization, suggesting that developmental processes may be compromised at realistically high temperatures. These results confirm that genes from the Hsp families play vital roles in the thermal tolerance of developing reptile embryos and, in addition with a number of other genes, should be targets for evaluating the capacity of oviparous reptiles to respond adaptively to the effects of climate change.

Heat Shock Proteins and Maternal Contribution to Oogenesis and Early Embryogenesis

Early embryos develop from fertilized eggs using materials that are stored during oocyte growth and which can be defined as maternal contribution (molecules, factors, or determinants). Several heat shock proteins (HSPs) and the heat shock transcriptional factor (HSF) are part of the maternal contribution that is critical for successful embryogenesis and reproduction. A maternal role for heat shock-related genes was mainly demonstrated in genetic experimental organisms (e.g., fly, nematode, mouse). Nowadays, an increasing number of "omics" data are produced from a large panel of organisms implementing a catalog of maternal and/or embryonic HSPs and HSFs. However, for most of them, it remains to better understand their potential roles in this context. Existing and future genome-wide screens mainly set up to create loss-of-function are likely to improve this situation. This chapter will discuss available data from various experimental organisms following the developmental steps from egg production to early embryogenesis.