Molecular Stress Response Research Articles

Genome-Wide Stress Responses to Copper and Arsenic in a Field Population of Daphnia.

Over the past decade, significant advances have been made to unravel molecular mechanisms of stress response in different ecotoxicological model species. Within this study, we focus on population level transcriptomic responses of a natural population of Daphnia magna Straus, (1820), to heavy metals. We aim to characterize the population level transcriptomic responses, which include standing genetic variation, and improve our understanding on how populations respond to environmental stress at a molecular level. We studied population level responses to two heavy metals, copper and arsenic, and their binary mixture across time. Transcriptomic patterns identified significantly regulated gene families and genes at the population level including cuticle proteins and resilins. Furthermore, some of these differentially regulated gene families, such as cuticle proteins, were also significantly enriched for genetic variations including SNPs and MNPs. In general, genetic variation was observed in specific gene families, many of which are known to be involved in stress response. Overall, our results indicate that molecular stress responses can be identified within natural populations and that linking molecular mechanisms with genetic variation at the population level could contribute significantly to adverse outcome frameworks.

Evidence from the proteome for local adaptation to extreme heat in a widespread tree species

Abstract Heatwaves are increasing in frequency and intensity globally with negative consequences for biological function. Assessing the effect of extreme heat on species requires an understanding of their adaptive capacity for mitigating physiological damage. Where long‐term exposure to extreme heat in natural populations provides sufficient selection pressure, populations should exhibit signals of adaptive thermotolerance to temperature extremes. Using quantitative proteomics, we tested this idea in the widespread and commercially important tree species Eucalyptus grandis (Flooded Gum). Seedlings from six natural populations of E. grandis spanning a 2,000 km gradient were exposed to a four‐day extreme heat treatment (42–24°C day–night cycle) in experimental growth chambers. Populations differed in their long‐term exposure to extreme heat conditions, defined both as the number of days annually ≥15°C above mean annual temperature (MAT), and average number of days annually with temperature maxima ≥35°C between 1960 and 1990. Long‐term exposure to extreme heat conditions in the field predicted the protein‐level response of E. grandis to experimental heatwaves. Relationships between long‐term extreme heat exposure and protein increases were positive and linear for all combinations of extreme heat (days ≥15°C above MAT, mean days with temperature maxima ≥35°C annually) and expression (all differentially expressed proteins, isolated heat shock proteins, proteins involved in molecular stress responses). Although extreme climate events are typically rare (e.g., 1 day 15° ≥MAT per 5 years in some populations in our study), E. grandis populations sampled from across a 2,000 km range exhibit a clear capacity to increase expression of proteins involved in heat stress in response to simulated heatwave exposure. Presumably, they respond similarly under natural heatwave conditions. We show that a long‐lived species with a broad environmental niche exhibits adaptive variation in protein response to temperature extremes at the population level. This implies that restoration, translocation and silvicultural programmes should consider the molecular response of source populations to climatic extremes to maximize success under future climates. Tree populations with low exposure to extreme heat conditions may be limited in their ability to respond to heatwave events, potentially limiting their adaptive capacity to withstand novel climate conditions. A plain language summary is available for this article.

Molecular cloning and stress response of PPARγ in Coilia nasus

Molecular cloning and stress response of <i>PPARγ</i> in <i>Coilia nasus</i>

Smart Plasmonic Nanorobot for Real-Time Monitoring Cytochrome c Release and Cell Acidification in Apoptosis during Electrostimulation.

Cytochrome c (Cyt c) release and cellular pH change are two important mediators of apoptosis. Effective methods to regulate or monitor such two events are therefore highly desired for apoptosis research and cancer cell therapy. Herein, we exploited electrostimulation to regulate cellular Cyt c release and apoptosis process, and by designing and preparing a smart and efficient plasmonic nanorobot (with surface-modified Cyt c-specific aptamer and 4-mercaptobenzoic acid) that is capable of Cyt c capture and self-sensing, we achieved real-time SERS monitoring of dynamic Cyt c release and simultaneous cell acidification in apoptosis during electrostimulation. Distinctly different molecular stress responses in the two events for cancerous MCF-7 and HeLa cells and normal L929 cells were identified and revealed. The method and results are valuable and promising for apoptosis and Cyt c-mediated biology studies.

Biotic and Abiotic Stress Responses in Crop Plants

Agricultural productivity depends on increasingly extreme weather phenomena, and the use of germplasm that has to be continuously improved by plant breeders to become tolerant to various biotic and abiotic stresses. Molecular plant biologists try to understand the mechanisms associated with stress responses and provide knowledge that could be used in breeding programs. To provide a partial overview about our current understanding about molecular and physiological stress responses, and how this knowledge can be used in agriculture, we have edited a special issue on “Biotic and Abiotic Stress Responses in Crop Plants”. Contributions are from different fields including heat stress responses, stress responses during drought and salinity, as well as during flooding, and resistance and susceptibility to pathogenetic stresses and about the role of plant functional metabolites in biotic stress responses. Future research demand in particular areas of crop stress physiology is discussed, as well as the importance of translational research and investigations directly in elite crop plants and in the genetic resources available for breeding.

Nucleus and Mitochondria Targeting Theranostic Plasmonic Surface-Enhanced Raman Spectroscopy Nanoprobes as a Means for Revealing Molecular Stress Response Differences in Hyperthermia Cell Death between Cancerous and Normal Cells.

Metallic plasmonic nanoparticles have been intensively exploited as theranostic nanoprobes for plasmonic photothermal therapy (PPT) and surface-enhanced Raman spectroscopy (SERS) applications. But the underlying molecular mechanisms associated with PPT-induced apoptosis between cancerous and normal cells have remained largely unknown or disputed. In this study, we designed an organelle-targeting theranostic plasmonic SERS nanoprobe (CDs-Ag/Au NS) composed of porous Ag/Au nanoshell (p-Ag/Au NSs) and carbon dots (CDs) for nucleus and mitochondria targeted PPT of cells. The differences in molecular stress response in the PPT-induced hyperthermia cell death between cancerous HeLa and normal L929 and H8 cells have been revealed by site-specific single-cell SERS detection. The contents of tryptophan (Trp), phenylalanine (Phe), and tyrosine (Tyr) in HeLa cells were found more evidently increased than L929 and H8 cells during the PPT-induced cell-death process. And from the mitochondria point of view, we found that the PPT-induced cell apoptosis for HeLa cells mainly stems from (or is regulated through) cellular thermal stress-responsive proteins, while for L929 and H8 cells it seems more related to DNA. Understanding molecular stress response difference of the PPT-induced cell apoptosis between cancerous and normal cells is helpful for diagnosis and treatment of cancer, and the method will open an avenue for single-cell studies.

The Stress Response in the Non-sensory Cells of the Cochlea Under Pathological Conditions-Possible Role in Mediating Noise Vulnerability.

Various stressors, such as loud sounds and the effects of aging, impair the function and viability of the cochlear sensory cells, the hair cells. Stressors trigger pathophysiological changes in the cochlear non-sensory cells as well. We have here studied the stress response mounted in the lateral wall of the cochlea during acute noise stress and during age-related chronic stress. We have used the activation of JNK/c-Jun, ERK, and NF-κB pathways as a readout of the stress response, and the expression of the FoxO3 transcription factor as a possible additional player in cellular stress. In the aging cochlea, NF-κB transcriptional activity was strongly induced in the stria vascularis of the lateral wall. This induction was linked with the atrophy of the stria vascularis, suggesting a role for NF-κB signaling in mediating age-related strial degeneration. Acutely following noise exposure, the JNK/c-Jun, ERK, and NF-κB pathways were activated in the spiral ligament of the lateral wall of CBA/Ca mice. This activation was concomitant with the morphological transformation of macrophages, suggesting that the upregulation of stress signaling leads to macrophage activation. In contrast, C57BL/6J mice lacked these responses. Only the combination of noise exposure and a systemic stressor, lipopolysaccharide, exceeded the threshold for the activation of stress signaling in the lateral wall of C57BL/6J mice. In addition, we found that, at the young adult age, outer hair cells of CBA/Ca mice are much more vulnerable to loud sounds compared to these cells of C57BL/6J mice. These results suggest that the differential stress response in the lateral wall of the two mouse strains underlies, in part, the differential noise vulnerability of their outer hair cells. Together, we propose that the molecular stress response in the lateral wall modulates the outcome of the stressed cochlea.

SAL1-PAP retrograde signalling extends circadian period by reproducing the loss of exoribonuclease (XRN) activity

ABSTRACTPlants have developed an internal timing mechanism, the circadian system, that serves to synchronise physiological and metabolic functions with daily cues such as dawn and dusk, and provides plants with an advantage in adapting to changing and challenging conditions. We have recently shown that the SAL1-PAP-XRN retrograde signalling pathway, which is proposed to regulate plant responses under stress conditions, also acts within the circadian system. Here we provide further evidence of circadian regulation by SAL1-PAP-XRN signalling, thereby affirming a link between molecular timekeeping and abiotic stress response mechanisms.

Comparative toxicity of silver nanoparticle and ionic silver in juvenile common carp (Cyprinus carpio): Accumulation, physiology and histopathology

Many studies have investigated the potential negative effects of silver on aquatic organisms, but most focused on short-term exposure in few species. Moreover, there are many uncertainties about differences in potential toxicity mechanisms and adverse effects of silver nanoparticles (AgNPs) and ionic form of silver (AgNO3). We investigated chronic effects of AgNPs and AgNO3 on the juvenile common carp (Cyprinus carpio). AgNPs and AgNO3 accumulated in the liver, gill and intestine, respectively and highest was related to AgNPs. Our results indicated, silver uptake was accompanied with histological alteration in the target organs such that different tissue lesions were observed in exposed groups. Superoxide dismutase (SOD), catalase (CAT) and lactate dehydrogenase (LDH) activity and also hsp70, ghrelin and IGF-1 genes expression were induced in both forms. After 7 days, highest hsp70 gene expression was observed in AgNO3 treatment and highest ghrelin and IGF-1 gene expression was observed in AgNPs treatment. The results revealed that adverse effects of AgNPs on different aspects of the health of juvenile common carp, may not be solely a result of particle dissolution. In addition, the main toxic mechanism of AgNPs was probably related to the accumulation of silver followed by the molecular and oxidative stress response.

Gene expression analysis in response to combined salt and boron (B) stresses in a tolerant maize landrace

To understand the molecular stress response in maize plants to high salt and boron (B) stress, we focused on the transcript accumulation of six stress-related genes in Lluteno maize, a sweet corn l...

Dysregulated Inflammation And MAPK Signaling In Aged Human Muscle Following Exercise-induced Damage

The remarkable capacity of skeletal muscle to adapt and repair following injury is attenuated with age. Studies in young organisms suggest that acute changes in both extrinsic and intrinsic factors in the muscle environment are critical in regulating reparative potential. PURPOSE: To uncover potential factors involved in the impaired regenerative response of aged human skeletal muscle, we comprehensively assessed the molecular stress response following muscle damage in young and old individuals. METHODS: 11 young (22.7 ± 2.25 yrs) and 8 physically active old (70.9 ± 7.5 yrs) subjects completed a bout of 300 lengthening contractions (LC) on a Biodex dynamometer. Functional tests were performed as an indirect assessment of muscle damage and muscle biopsies were taken pre-exercise and at 3, 24, and 72 hours post-exercise. High throughput multi- plexing bead assays were used to analyze biopsy samples for content of inflammatory cytokines and protein concentrations of the mitogen activated protein kinase (MAPK) signaling pathway. RESULTS: After the bout of LC’s, muscle damage was evident by the loss of isometric force production in both groups (Young: 54.11 ± 22 and Old: 33.86 ± 17%). Old muscle displayed higher expression of MCP-1 (group, p=0.019) that appeared at the later 24 and 72 hour time points. There was also a rapid increase in NF-kb activity in the old following the bout of lengthening contractions (group x time, p=0.05). In the old, p38 protein content increased significantly at the 3 hour time point (Young: 0.8 ± 0.09 vs Old: 1.70 ± 0.47 fold) before returning to pre-exercise levels (group x time, p=0.0043). Additionally, by 3 hours post-exercise total JNK protein levels increased only in the old (Young: 1.6 ± 0.26 vs Old: 5.1 ± 0.77 fold) and remained significantly elevated (Young: 0.76 ± 0.20 vs Old: 4.5 ± 0.46 fold) 24 hours post-exercise (group x time, p=0.038) before returning to pre-exercise levels. CONCLUSION: skeletal muscle of physically active older individuals is characterized by a dysregulated and asynchronous inflammatory and MAPK response, each of which may individually or collectively contribute to the deterioration of muscle repair mechanisms that accompanies aging.

Acute extracellular matrix, inflammatory and MAPK response to lengthening contractions in elderly human skeletal muscle

To uncover potential factors that may be involved in the impaired regenerative capacity of aged skeletal muscle, we comprehensively assessed the molecular stress response following muscle damage in old and young individuals. 10 young (22.7 ± 2.25 yrs) and 8 physically active old (70.9 ± 7.5 yrs) subjects completed a bout of 300 lengthening contractions (LC), and muscle biopsies were taken pre-exercise and at 3, 24, and 72 h post-LC. Both age groups performed the same amount of work during LC, with the old group displaying a resistance to LC-induced fatigue during the exercise. Muscle damage was evident by soreness and losses in isokinetic force and power production, though older subjects experienced reduced force and power losses relative to the young group. The acute extracellular matrix (ECM) response was characterized by substantial increases in the glycoproteins tenascin C and fibronectin in the young, which were blunted in the old muscle following damage. Old muscle displayed a generally heightened and asynchronous inflammatory response compared to young muscle, with higher expression of MCP-1 that appeared at later time points, and increased NF-κb activity. Expression of the stress-related MAPKs P38 and JNK increased only in the old groups following muscle damage. In summary, aberrations appear in the inflammatory, ECM and MAPK responses of aged skeletal muscle following damaging LC, each of which may individually or collectively contribute to the deterioration of muscle repair mechanisms that accompanies aging.

Combined multivariate analysis and machine learning reveals a predictive module of metabolic stress response in Arabidopsis thaliana.

Abiotic stress exposure of plants induces metabolic reprogramming which is tightly regulated by signalling cascades connecting transcriptional with translational and metabolic regulation. Complexity of such interconnected metabolic networks impedes the functional understanding of molecular plant stress response compromising the design of breeding strategies and biotechnological processes. Thus, defining a molecular network to enable the prediction of a plant's stress mode will improve the understanding of stress responsive biochemical regulation and will yield novel molecular targets for technological application. Arabidopsis wild type plants and two mutant lines with deficiency in sucrose or starch metabolism were grown under ambient and combined cold/high light stress conditions. Stress-induced dynamics of the primary metabolome and the proteome were quantified by mass spectrometry. Wild type data were used to train a machine learning algorithm to classify mutant lines under control and stress conditions. Multivariate analysis and classification identified a module consisting of 23 proteins enabling the reliable prediction of combined temperature/high light stress conditions. 18 of these 23 proteins displayed putative protein-protein interactions connecting transcriptional regulation with regulation of primary and secondary metabolism. The identified stress-responsive core module supports prediction of complex biochemical regulation under changing environmental conditions.

Interactive effects of nutrition, reproductive state and pollution on molecular stress responses of mussels, Mytilus galloprovincialis Lamarck, 1819

Marine bivalves including mussels Mytilus galloprovincialis are commonly used as sentinels for pollution monitoring and ecosystem health assessment in the coastal zones. Use of biomarkers to assess the pollution effects assumes that the effects of pollutants on the biomarkers exceed the natural background variability; yet this assumption has rarely been tested. We exposed mussels at different reproductive stages and nutritive states to two concentrations of a polycyclic aromatic hydrocarbon (fluoranthene, 3 and 60 μg L−1) for three weeks. Expression levels of the molecular biomarkers related to the detoxification and general stress response [cytochrome P450 oxidase (CYP450), glutathione S-transferases (GST-α; GST-S1; GST-S2), the multixenobiotic resistance protein P-glycoprotein (PgP), metallothioneins (MT10 and MT20), heat shock proteins (HSP22, HSP70-2; HSP70-3; HSP70-4), as well as mRNA expression of two reproduction-related genes, vitellogenin (Vitel) and vitelline coat lysin M7 (VCLM7)] were measured. The mussels’ nutrition and reproductive state affected the baseline mRNA levels of molecular biomarkers and modulated the transcriptional responses of biomarker genes to the pollutant exposure. Thus, mussel physiological state could act as a confounding factor in the evaluation of the response of pollution through molecular biomarkers. The biomarker baseline levels must be determined across a range of physiological states to enable the use of biomarkers in monitoring programs.

Intraspecific differences in molecular stress responses and coral pathobiome contribute to mortality under bacterial challenge in Acropora millepora

Disease causes significant coral mortality worldwide; however, factors responsible for intraspecific variation in disease resistance remain unclear. We exposed fragments of eight Acropora millepora colonies (genotypes) to putatively pathogenic bacteria (Vibrio spp.). Genotypes varied from zero to >90% mortality, with bacterial challenge increasing average mortality rates 4–6 fold and shifting the microbiome in favor of stress-associated taxa. Constitutive immunity and subsequent immune and transcriptomic responses to the challenge were more prominent in high-mortality individuals, whereas low-mortality corals remained largely unaffected and maintained expression signatures of a healthier condition (i.e., did not launch a large stress response). Our results suggest that lesions appeared due to changes in the coral pathobiome (multiple bacterial species associated with disease) and general health deterioration after the biotic disturbance, rather than the direct activity of any specific pathogen. If diseases in nature arise because of weaknesses in holobiont physiology, instead of the virulence of any single etiological agent, environmental stressors compromising coral condition might play a larger role in disease outbreaks than is currently thought. To facilitate the diagnosis of compromised individuals, we developed and independently cross-validated a biomarker assay to predict mortality based on genes whose expression in asymptomatic individuals coincides with mortality rates.

Heat shock and prolonged heat stress attenuate neurotoxin and sporulation gene expression in group I Clostridium botulinum strain ATCC 3502.

Foodborne pathogenic bacteria are exposed to a number of environmental stresses during food processing, storage, and preparation, and in the human body. In order to improve the safety of food, the understanding of molecular stress response mechanisms foodborne pathogens employ is essential. Many response mechanisms that are activated during heat shock may cross-protect bacteria against other environmental stresses. To better understand the molecular mechanisms Clostridium botulinum, the causative agent of botulism, utilizes during acute heat stress and during adaptation to stressfully high temperature, the C. botulinum Group I strain ATCC 3502 was grown in continuous culture at 39°C and exposed to heat shock at 45°C, followed by prolonged heat stress at 45°C to allow adaptation of the culture to the high temperature. Growth in continuous culture was performed to exclude secondary growth phase effects or other environmental impacts on bacterial gene transcription. Changes in global gene expression profiles were studied using DNA microarray hybridization. During acute heat stress, Class I and III heat shock genes as well as members of the SOS regulon were activated. The neurotoxin gene botA and genes encoding the neurotoxin-associated proteins were suppressed throughout the study. Prolonged heat stress led to suppression of the sporulation machinery whereas genes related to chemotaxis and motility were activated. Induced expression of a large proportion of prophage genes was detected, suggesting an important role of acquired genes in the stress resistance of C. botulinum. Finally, changes in the expression of a large number of genes related to carbohydrate and amino acid metabolism indicated remodeling of the cellular metabolism.

Molecular cloning, expression and oxidative stress response of the vitellogenin Gene (AccVg) from Apis cerana cerana

Vitellogenin (Vg) is a yolk precursor protein in most oviparous females. However, Vg has not been studied in the Apis cerana cerana. In this work, the Vg gene of the A. cerana cerana has been cloned and sequenced. The gene codes for a protein consisting of 1770 amino acids in seven exons with a predicted molecular mass and isoelectric point of 200 kDa and 6.46, respectively. Additionally, an 807-bp 5′-flanking region was isolated, and potential transcription factor binding sites associated with development and stress response were identified. Quantitative real-time PCR analysis showed that AccVg is highly expressed in pupae during different developmental stages. In addition, the expression of AccVg could be induced by cold (4 and 16 °C), CdCl2, and pesticide treatment. Real-time quantitative PCR (RT-PCR) and western blot analyses indicated that AccVg transcription was induced by various abiotic stresses. Western blot was used to measure the expression levels of AccVg protein. Taken together, these results suggest that AccVg most likely plays essential roles in antioxidant defence and that it may be of critical importance to honey bee survival.

Integrating Molecular Control to Improve Cryopreservation Outcome.

Cryopreservation (CP) is a critical component in enabling on-demand access to biological material (macromolecules, cells, and tissues), yet CP has evolved little over the last several decades. Today's CP processes often yield a suboptimal "product," which has slowed progression in areas such as cell therapy and stem cell research. Recent discoveries focusing on molecular control and buffering of cell stress responses to CP as well as the development of new devices that improve sample freezing and thawing are now providing a path to improve sample quality. Numerous reports now identify the problems associated with CP-induced delayed-onset cell death (CIDOCD), with a focus on the mitigation of cell stress responses through freeze media formulation to optimize survival during "cold chain" sample management. Importantly, these new approaches that manage cell stress response are now providing a basis for advancements in cell therapy development. Herein, we provide an overview of the molecular stress responses of cells to CP, including the impact of hypothermic and cell death continuums and the strategies for improving preservation outcome.

Deciphering the soybean molecular stress response via high-throughput approaches.

As a result of thousands of years of agriculture, humans had created many crop varieties that became the basis of our daily diet, animal feed and also carry industrial application. Soybean is one of the most important crops worldwide and because of its high economic value the demand for soybean products is constantly growing. In Europe, due to unfavorable climate conditions, soybean cultivation is restricted and we are forced to rely on imported plant material. The development of agriculture requires continuous improvements in quality and yield of crop varieties under changing or adverse conditions, namely stresses. To achieve this goal we need to recognize and understand the molecular dependencies underlying plant stress responses. With the advent of new technologies in studies of plant transcriptomes and proteomes, now we have the tools necessary for fast and precise elucidation of desirable crop traits. Here, we present an overview of high-throughput techniques used to analyze soybean responses to different abiotic (drought, flooding, cold stress, salinity, phosphate deficiency) and biotic (infections by F. oxysporum, cyst nematode, SMV) stress conditions at the level of the transcriptome (mRNAs and miRNAs) and the proteome.

Detection and Manipulation of the Stress Response Protein Metallothionein.

Metallothioneins (MTs) are small molecular weight stress response proteins that play a central role as reservoir of essential divalent heavy metal cations such as zinc and copper, and also can diminish the effects of toxic heavy metals such as mercury and cadmium. Historically, MT has been considered to be an intracellular protein with roles to play in the management of heavy metals, as a regulator of cellular redox potential, and as a buffer of free radicals. Our recent studies have highlighted immunomodulatory role of MT in inflammatory diseases and also in the progression of metastatic cell movement. Hence, manipulation and detection of MT is essential for its possible use as a diagnostic and in therapeutic interventions of chronic inflammation. This review describes procedures used to detect MT using techniques such as western immunoblot, competition ELISA, flow cytometry and immunohistochemistry. Additionally, it also describes the use of a colorimetric cell proliferation assay (CellTiter 96 AQueous One Solution/MTS) to study the proliferative effect of MT. © 2017 by John Wiley & Sons, Inc.