scholarly journals A core of functionally complementary bacteria colonizes oysters in Pacific Oyster Mortality Syndrome

2020 ◽  
Author(s):  
Aude Lucasson ◽  
Xing Luo ◽  
Shogofa Mortaza ◽  
Julien de Lorgeril ◽  
Eve Toulza ◽  
...  
Keyword(s):  
Stress Responses ◽  
Pacific Oyster ◽  
Sulfur Metabolism ◽  
Redox Homeostasis ◽  
Bacterial Consortium ◽  
Adaptive Responses ◽  
Cell Defense ◽  
Highly Active ◽  
Sequence Of Events ◽  
Oyster Mortality

ABSTRACTThe Pacific oyster Crassostrea gigas is one of the main cultivated invertebrate species around the world. Since 2008, oyster juveniles have been confronted with a lethal syndrome, Pacific Oyster Mortality Syndrome (POMS). The etiology of POMS is complex. Recently, we demonstrated that POMS is a polymicrobial disease. It is initiated by a primary infection with the herpesvirus OsHV-1 μ Var, and evolves towards a secondary fatal bacteremia that is enabled by the oyster’s immunocompromised state. In the present article, we describe the implementation of an unprecedented combination of metabarcoding and metatranscriptomic approaches to show that the sequence of events in POMS pathogenesis is conserved across infectious environments and susceptible oyster genetic backgrounds. We also identify a core colonizing bacterial consortium which, together with OsHV-1 μ Var, forms the POMS pathobiota. This bacterial core is characterized by highly active global metabolism and key adaptive responses to the within-host environment (e.g. stress responses and redox homeostasis). Several marine gamma proteobacteria in the core express different and complementary functions to exploit the host’s resources. Such cross-benefits are observed in colonization-related functions, and reveal specific strategies used by these bacteria to adapt and colonize oysters (e.g. adhesion, cell defense, cell motility, metal homeostasis, natural competence, quorum sensing, transport, and virulence). Interdependence and cooperation within the microbial community for metabolic requirements is best exemplified by sulfur metabolism, which is a property of the pathobiota as a whole and not of a single genus. We argue that this interdependence may dictate the conservation of the POMS pathobiota across distinct environments and oyster genetic backgrounds.

scholarly journals Differential basal expression of immune genes confers Crassostrea gigas resistance to Pacific Oyster Mortality Syndrome

2020 ◽  
Author(s):  
de Lorgeril Julien ◽  
Bruno Petton ◽  
Aude Lucasson ◽  
Valérie Perez ◽  
Pierre-Louis Stenger ◽  
...  
Keyword(s):  
Stress Responses ◽  
Pacific Oyster ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Dna Integrity ◽  
Immune Genes ◽  
Basal Expression ◽  
Oyster Mortality ◽  
Underlying Mechanisms ◽  
Polymicrobial Disease

Abstract Background: As a major threat to the oyster industry, Pacific Oyster Mortality Syndrome (POMS) is a polymicrobial disease affecting the main oyster species farmed across the world. POMS affects oyster juveniles and became panzootic this last decade, but POMS resistance in some oyster genotypes has emerged. While we know some genetic loci associated with resistance, the underlying mechanisms remained uncharacterized. So, we developed a comparative transcriptomic approach using basal gene expression profiles between different oyster biparental families with contrasted phenotypes when confronted to POMS (resistant or susceptible). Results: We showed that POMS resistant oysters show differential expression of genes involved in stress responses, protein modifications, maintenance of DNA integrity and repair, and immune and antiviral pathways. We found similarities and clear differences among different molecular pathways in the different resistant families. These results suggest that the resistance process is polygenic and partially varies according to the oyster genotype. Conclusions: We found differences in basal expression levels of genes related to TLR-NFκB, JAK-STAT and STING-RLR pathways. These differences could explain the best antiviral response, as well as the robustness of resistant oysters when confronted to POMS. As some of these genes represent valuable candidates for selective breeding, we propose future studies should further examine their function.

scholarly journals Differential basal expression of immune genes confers Crassostrea gigas resistance to Pacific Oyster Mortality Syndrome

2019 ◽  
Author(s):  
de Lorgeril Julien ◽  
Bruno Petton ◽  
Aude Lucasson ◽  
Valérie Perez ◽  
Pierre-Louis Stenger ◽  
...  
Keyword(s):  
Stress Responses ◽  
Pacific Oyster ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Dna Integrity ◽  
Immune Genes ◽  
Basal Expression ◽  
Oyster Mortality ◽  
Underlying Mechanisms ◽  
Polymicrobial Disease

Abstract Background As a major threat to the oyster industry, Pacific Oyster Mortality Syndrome (POMS) is a polymicrobial disease affecting the main oyster species farmed across the world. POMS affects oyster juveniles and became panzootic this last decade, but POMS resistance in some oyster genotypes has emerged. While we know some genetic loci associated with resistance, the underlying mechanisms remained uncharacterized. So, we developed a comparative transcriptomic approach using basal gene expression profiles between different oyster biparental families with contrasted phenotypes when confronted to POMS (resistant or susceptible).Results We showed that POMS resistant oysters show differential expression of genes involved in stress responses, protein modifications, maintenance of DNA integrity and repair, and immune and antiviral pathways. We found similarities and clear differences among different molecular pathways in the different resistant families. These results suggest that the resistance process is polygenic and partially varies according to the oyster genotype.Conclusions We found differences in basal expression levels of genes related to TLR-NFκB, JAK-STAT and STING-RLR pathways. These differences could explain the best antiviral response, as well as the robustness of resistant oysters when confronted to POMS. As some of these genes represent valuable candidates for selective breeding, we propose future studies should further examine their function.

scholarly journals Increasing Solvent Tolerance to Improve Microbial Production of Alcohols, Terpenoids and Aromatics

2021 ◽  
Vol 9 (2) ◽  
pp. 249
Author(s):  
Thomas Schalck ◽  
Bram Van den Bergh ◽  
Jan Michiels
Keyword(s):  
Stress Responses ◽  
Small Rnas ◽  
Defense Mechanisms ◽  
Industrial Processes ◽  
Solvent Tolerance ◽  
Adaptive Responses ◽  
Environment Friendly ◽  
Pathway Optimization ◽  
Polymer Precursors ◽  
Product Accumulation

Fuels and polymer precursors are widely used in daily life and in many industrial processes. Although these compounds are mainly derived from petrol, bacteria and yeast can produce them in an environment-friendly way. However, these molecules exhibit toxic solvent properties and reduce cell viability of the microbial producer which inevitably impedes high product titers. Hence, studying how product accumulation affects microbes and understanding how microbial adaptive responses counteract these harmful defects helps to maximize yields. Here, we specifically focus on the mode of toxicity of industry-relevant alcohols, terpenoids and aromatics and the associated stress-response mechanisms, encountered in several relevant bacterial and yeast producers. In practice, integrating heterologous defense mechanisms, overexpressing native stress responses or triggering multiple protection pathways by modifying the transcription machinery or small RNAs (sRNAs) are suitable strategies to improve solvent tolerance. Therefore, tolerance engineering, in combination with metabolic pathway optimization, shows high potential in developing superior microbial producers.

A Functional Alternative Oxidase Modulates Plant Salt Tolerance in Physcomitrella patens

2019 ◽  
Vol 60 (8) ◽  
pp. 1829-1841 ◽  
Author(s):  
Guochun Wu ◽  
Sha Li ◽  
Xiaochuan Li ◽  
Yunhong Liu ◽  
Shuangshuang Zhao ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Stress Responses ◽  
Alternative Oxidase ◽  
Physcomitrella Patens ◽  
Redox Homeostasis ◽  
Respiratory Pathway ◽  
Functional Link ◽  
Salt Stress Condition ◽  
Plant Salt Tolerance

Abstract Alternative oxidase (AOX) has been reported to be involved in mitochondrial function and redox homeostasis, thus playing an essential role in plant growth as well as stress responses. However, its biological functions in nonseed plants have not been well characterized. Here, we report that AOX participates in plant salt tolerance regulation in moss Physcomitrella patens (P. patens). AOX is highly conserved and localizes to mitochondria in P. patens. We observed that PpAOX rescued the impaired cyanide (CN)-resistant alternative (Alt) respiratory pathway in Arabidopsis thaliana (Arabidopsis) aox1a mutant. PpAOX transcription and Alt respiration were induced upon salt stress in P. patens. Using homologous recombination, we generated PpAOX-overexpressing lines (PpAOX OX). PpAOX OX plants exhibited higher Alt respiration and lower total reactive oxygen species accumulation under salt stress condition. Strikingly, we observed that PpAOX OX plants displayed decreased salt tolerance. Overexpression of PpAOX disturbed redox homeostasis in chloroplasts. Meanwhile, chloroplast structure was adversely affected in PpAOX OX plants in contrast to wild-type (WT) P. patens. We found that photosynthetic activity in PpAOX OX plants was also lower compared with that in WT. Together, our work revealed that AOX participates in plant salt tolerance in P. patens and there is a functional link between mitochondria and chloroplast under challenging conditions.

scholarly journals Strigolactone GR24 upregulates Nrf2 target genes and may protect against oxidative stress in skeletal muscle

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1459
Author(s):  
Shalem Raju Modi ◽  
Tarja Kokkola
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Skeletal Muscle ◽  
Transcription Factor ◽  
Stress Responses ◽  
Mycorrhizal Fungi ◽  
Target Genes ◽  
Redox Homeostasis ◽  
Antioxidant Defences ◽  
Microarray Gene Expression

GR24 is a synthetic strigolactone analog, demonstrated to regulate the development of plants and arbuscular mycorrhizal fungi. GR24 possesses anti-cancer and anti-apoptotic properties, enhances insulin sensitivity and mitochondrial biogenesis in skeletal myotubes, inhibits adipogenesis, decreases inflammation in adipocytes and macrophages and downregulates the expression of hepatic gluconeogenic enzymes. Transcription factor Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) is a master regulator of antioxidant response, regulating a multitude of genes involved in cellular stress responses and anti-inflammatory pathways, thus maintaining cellular redox homeostasis. Nrf2 activation reduces the deleterious effects of mitochondrial toxins and has multiple roles in promoting mitochondrial function and dynamics. We studied the role of GR24 on gene expression in rat L6 skeletal muscle cells which were differentiated into myotubes. The myotubes were treated with GR24 and analyzed by microarray gene expression profiling. GR24 upregulated the cytoprotective transcription factor Nrf2 and its target genes, activating antioxidant defences, suggesting that GR24 may protect skeletal muscle from the toxic effects of oxidative stress.

scholarly journals Small extracellular vesicles convey the stress-induced adaptive responses of melanoma cells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria Harmati ◽  
Edina Gyukity-Sebestyen ◽  
Gabriella Dobra ◽  
Laszlo Janovak ◽  
Imre Dekany ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Extracellular Vesicles ◽  
Stress Responses ◽  
In Silico ◽  
Specific Response ◽  
Response Patterns ◽  
Adaptive Responses ◽  
Mediated Communication ◽  
Ki 67

Abstract Exosomes are small extracellular vesicles (sEVs), playing a crucial role in the intercellular communication in physiological as well as pathological processes. Here, we aimed to study whether the melanoma-derived sEV-mediated communication could adapt to microenvironmental stresses. We compared B16F1 cell-derived sEVs released under normal and stress conditions, including cytostatic, heat and oxidative stress. The miRNome and proteome showed substantial differences across the sEV groups and bioinformatics analysis of the obtained data by the Ingenuity Pathway Analysis also revealed significant functional differences. The in silico predicted functional alterations of sEVs were validated by in vitro assays. For instance, melanoma-derived sEVs elicited by oxidative stress increased Ki-67 expression of mesenchymal stem cells (MSCs); cytostatic stress-resulted sEVs facilitated melanoma cell migration; all sEV groups supported microtissue generation of MSC-B16F1 co-cultures in a 3D tumour matrix model. Based on this study, we concluded that (i) molecular patterns of tumour-derived sEVs, dictated by the microenvironmental conditions, resulted in specific response patterns in the recipient cells; (ii) in silico analyses could be useful tools to predict different stress responses; (iii) alteration of the sEV-mediated communication of tumour cells might be a therapy-induced host response, with a potential influence on treatment efficacy.

scholarly journals Microbiota Composition and Evenness Predict Survival Rate of Oysters Confronted to Pacific Oyster Mortality Syndrome

2020 ◽  
Vol 11 ◽  
Author(s):  
Camille Clerissi ◽  
Julien de Lorgeril ◽  
Bruno Petton ◽  
Aude Lucasson ◽  
Jean-Michel Escoubas ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pacific Oyster ◽  
Microbiota Composition ◽  
Oyster Mortality

scholarly journals RNA-seq analysis provides insights into cold stress responses of Xanthomonas citri pv. citri

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Jin-Xing Liao ◽  
Kai-Huai Li ◽  
Jin-Pei Wang ◽  
Jia-Ru Deng ◽  
Qiong-Guang Liu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Low Temperature ◽  
Cold Stress ◽  
Stress Responses ◽  
Citrus Canker ◽  
Transcriptional Analysis ◽  
Adaptive Responses ◽  
Xanthomonas Citri ◽  
Type Iv ◽  
Expression Of Genes

Abstract Background Xanthomonas citri pv. citri (Xcc) is a citrus canker causing Gram-negative bacteria. Currently, little is known about the biological and molecular responses of Xcc to low temperatures. Results Results depicted that low temperature significantly reduced growth and increased biofilm formation and unsaturated fatty acid (UFA) ratio in Xcc. At low temperature Xcc formed branching structured motility. Global transcriptome analysis revealed that low temperature modulates multiple signaling networks and essential cellular processes such as carbon, nitrogen and fatty acid metabolism in Xcc. Differential expression of genes associated with type IV pilus system and pathogenesis are important cellular adaptive responses of Xcc to cold stress. Conclusions Study provides clear insights into biological characteristics and genome-wide transcriptional analysis based molecular mechanism of Xcc in response to low temperature.

scholarly journals Plasma Transcortin Influences Endocrine and Behavioral Stress Responses in Mice

Endocrinology ◽  
2010 ◽  
Vol 151 (2) ◽  
pp. 649-659 ◽  
Author(s):  
Elodie M. Richard ◽  
Jean-Christophe Helbling ◽  
Claudine Tridon ◽  
Aline Desmedt ◽  
Amandine M. Minni ◽  
...  
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Learned Helplessness ◽  
Critical Role ◽  
Adaptive Responses ◽  
Adrenal Axis ◽  
Response To Stress ◽  
Hypothalamus Pituitary Adrenal Axis ◽  
Deficient Mice ◽  
Pituitary Adrenal Axis

Glucocorticoids are released after hypothalamus-pituitary-adrenal axis stimulation by stress and act both in the periphery and in the brain to bring about adaptive responses that are essential for life. Dysregulation of the stress response can precipitate psychiatric diseases, in particular depression. Recent genetic studies have suggested that the glucocorticoid carrier transcortin, also called corticosteroid-binding globulin (CBG), may have an important role in stress response. We have investigated the effect of partial or total transcortin deficiency using transcortin knockout mice on hypothalamus-pituitary-adrenal axis functioning and regulation as well as on behaviors linked to anxiety and depression traits in animals. We show that CBG deficiency in mice results in markedly reduced total circulating corticosterone at rest and in response to stress. Interestingly, free corticosterone concentrations are normal at rest but present a reduced surge after stress in transcortin-deficient mice. No differences were detected between transcortin-deficient mice for anxiety-related traits. However, transcortin-deficient mice display increased immobility in the forced-swimming test and markedly enhanced learned helplessness after prolonged uncontrollable stress. The latter is associated with an approximately 30% decrease in circulating levels of free corticosterone as well as reduced Egr-1 mRNA expression in hippocampus in CBG-deficient mice. Additionally, transcortin-deficient mice show no sensitization to cocaine-induced locomotor responses, a well described corticosterone-dependent test. Thus, transcortin deficiency leads to insufficient glucocorticoid signaling and altered behavioral responses after stress. These findings uncover the critical role of plasma transcortin in providing an adequate endocrine and behavioral response to stress.

Sign in / Sign up

Export Citation Format

Share Document