scholarly journals What’s Genetic Variation Got to Do with It? Starvation-Induced Self-Fertilization Enhances Survival in Paramecium

2020 ◽  
Vol 12 (5) ◽  
pp. 626-638 ◽  
Author(s):  
Amarinder Singh Thind ◽  
Valerio Vitali ◽  
Mario Rosario Guarracino ◽  
Francesco Catania
Keyword(s):  
Genetic Variation ◽  
Stress Response ◽  
Sexual Reproduction ◽  
Stress Resistance ◽  
Evolutionary Biology ◽  
Molecular Mechanisms ◽  
Adaptive Significance ◽  
Paramecium Tetraurelia ◽  
Self Fertilization

Abstract The pervasiveness of sex despite its well-known costs is a long-standing puzzle in evolutionary biology. Current explanations for the success of sex in nature largely rely on the adaptive significance of the new or rare genotypes that sex may generate. Less explored is the possibility that sex-underlying molecular mechanisms can enhance fitness and convey benefits to the individuals that bear the immediate costs of sex. Here, we show that the molecular environment associated with self-fertilization can increase stress resistance in the ciliate Paramecium tetraurelia. This advantage is independent of new genetic variation, coupled with a reduced nutritional input, and offers fresh insights into the mechanistic origin of sex. In addition to providing evidence that the molecular underpinnings of sexual reproduction and the stress response are linked in P. tetraurelia, these findings supply an integrative explanation for the persistence of self-fertilization in this ciliate.

scholarly journals Sex enhances survival in Paramecium

2019 ◽  
Author(s):  
Amarinder Singh Thind ◽  
Valerio Vitali ◽  
Mario R. Guarracino ◽  
Francesco Catania
Keyword(s):  
Genetic Variation ◽  
Stress Response ◽  
Sexual Reproduction ◽  
Stress Resistance ◽  
Evolutionary Biology ◽  
Molecular Mechanisms ◽  
Adaptive Significance ◽  
Paramecium Tetraurelia ◽  
Self Fertilization

AbstractThe pervasiveness of sex despite its well-known costs is a long-standing puzzle in evolutionary biology. Current explanations for the success of sex in nature largely rely on the adaptive significance of the new or rare genotypes that sex may generate. Less explored is the possibility that sex-underlying molecular mechanisms can enhance fitness and convey benefits to the individuals that bear the immediate costs of sex. Here we show that self-fertilization can increase stress resistance in the ciliate Paramecium tetraurelia. This advantage is independent of new genetic variation, coupled with a reduced nutritional input, and offers fresh insights into the mechanistic origin of sex. In addition to providing evidence that the molecular underpinnings of sexual reproduction and the stress response are linked in P. tetraurelia, these findings supply an explanation for the persistence of self-fertilization in this ciliate.

The potential of new genetic technologies in selecting for stress resistance in pigs

2005 ◽  
Vol 45 (8) ◽  
pp. 775
Author(s):  
C. A. Kerr ◽  
B. M. Hines
Keyword(s):  
Gene Expression ◽  
Stress Response ◽  
Stress Resistance ◽  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Negative Impact ◽  
Experimental Models ◽  
Genetic Technologies ◽  
On Farm ◽  
Commercial Environment

This paper examines the potential for breeding stress resistance in pigs through an understanding of the physiology of the stress response and its associated genetic basis. Pigs reared in commercial units can encounter numerous concurrent stressors that can have a negative impact on performance and welfare. Stress induces physiological and behavioural responses that are multidimensional, consisting of a complex neuroendocrine and immune signalling milieu. Some stress-related genetic parameters have been identified using conventional genetic approaches applied in experimental models. However, these traits do not capture the complexity of the stress response. As a result, the molecular mechanisms underlying the variation associated with stress resistance in pigs in a commercial environment is poorly understood. Gene expression profiling is a powerful tool that can be applied to systematically elucidate stress response pathways and networks. Consequently, gene expression technologies have been applied to identify some putative stress-regulated genes. Further application of these and more traditional technologies will aid in elucidating stress resistance using gene expression as a measure of phenotypic variation at a molecular level. It is envisaged that in the future, tools for selecting for stress resistance could eventually be applied on-farm to enhance production, health and welfare status.

scholarly journals Genetic approaches in comparative and evolutionary physiology

2015 ◽  
Vol 309 (3) ◽  
pp. R197-R214 ◽  
Author(s):  
Jay F. Storz ◽  
Jamie T. Bridgham ◽  
Scott A. Kelly ◽  
Theodore Garland
Keyword(s):  
Quantitative Genetics ◽  
Evolutionary Biology ◽  
Molecular Mechanisms ◽  
Adaptive Significance ◽  
Physiological Traits ◽  
Evolutionary Physiology ◽  
Trait Variation ◽  
Polygenic Inheritance ◽  
Trade Offs ◽  
In The Wild

Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology.

scholarly journals Genetic basis of enhanced stress resistance in long-lived mutants highlights key role of innate immunity in determining longevity

2021 ◽  
Author(s):  
Sonja Soo ◽  
Paige Rudich ◽  
Meeta Mistry ◽  
Jeremy Van Raamsdonk
Keyword(s):  
Stress Response ◽  
Stress Resistance ◽  
Molecular Mechanisms ◽  
Bacterial Pathogen ◽  
Pathogen Resistance ◽  
Lifespan Extension ◽  
Sequencing Data ◽  
Enhanced Resistance ◽  
Resistance To Stress ◽  
Highly Correlated

Mutations that extend lifespan are associated with enhanced resistance to stress. To better understand the molecular mechanisms underlying this relationship, we studied nine long-lived C. elegans mutants representative of different pathways of lifespan extension. We directly compared the magnitude of their lifespan extension and their ability to resist various external stressors (heat, oxidative stress, bacterial pathogens, osmotic stress, and anoxia). Furthermore, we analysed gene expression in each of these mutants to identify genes and pathways responsible for the enhanced resistance to stress. All of the examined long-lived mutants have increased resistance to one or more type of stress. Resistance to each of the examined types of stress had a significant, positive correlation with lifespan, with bacterial pathogen resistance showing the strongest relationship. All of the examined long-lived mutants have significant upregulation of multiple stress response pathways but differ in which stress response pathway has the greatest enrichment of genes. We used RNA sequencing data to identify which genes are most highly correlated with each type of stress resistance. There was a highly significant overlap between genes highly correlated with stress resistance, and genes highly correlated with longevity, suggesting that the same genetic pathways drive both phenotypes. This was especially true for genes correlated with bacterial pathogen resistance, which showed an 84% overlap with genes correlated with lifespan. Overall, our results demonstrate a strong correlation between stress resistance and longevity that results from the high degree of overlap in genes contributing to each phenotype.

Waddington’s Processual Epigenetics and the Debate over Cryptic Variability

2018 ◽  
Author(s):  
Flavia Fabris
Keyword(s):  
Genetic Variation ◽  
Evolutionary Biology ◽  
Modern Synthesis ◽  
Genetic Assimilation ◽  
Ontological Difference ◽  
Epigenetic Process ◽  
Recent Debate ◽  
Acquired Characters

This chapter reappraises Waddington’s processual theory of epigenetics and examines its implications for contemporary evolutionary biology. It focuses in particular on the ontological difference between two conflicting assumptions that have been conflated in the recent debate over the nature of cryptic variability: a substance view that is consistent with the modern synthesis and construes variability as a preexisting pool of random genetic variation; and a processual view, which derives from Waddington’s conception of developmental canalization and understands variability as an epigenetic process. The chapter also discusses how these opposing interpretations fare in their capacity to explain the genetic assimilation of acquired characters.

scholarly journals Overexpression of the Apple (Malus× domestica) MdERF100 in Arabidopsis Increases Resistance to Powdery Mildew

2021 ◽  
Vol 22 (11) ◽  
pp. 5713
Author(s):  
Yiping Zhang ◽  
Li Zhang ◽  
Hai Ma ◽  
Yichu Zhang ◽  
Xiuming Zhang ◽  
...  
Keyword(s):  
Stress Response ◽  
Powdery Mildew ◽  
Malus Domestica ◽  
Molecular Mechanisms ◽  
Powdery Mildew Resistance ◽  
Bimolecular Fluorescence Complementation ◽  
Bhlh Protein ◽  
Mildew Resistance ◽  
Sa Signaling

APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factors play important roles in plant development and stress response. Although AP2/ERF genes have been extensively investigated in model plants such as Arabidopsis thaliana, little is known about their role in biotic stress response in perennial fruit tree crops such as apple (Malus × domestica). Here, we investigated the role of MdERF100 in powdery mildew resistance in apple. MdERF100 localized to the nucleus but showed no transcriptional activation activity. The heterologous expression of MdERF100 in Arabidopsis not only enhanced powdery mildew resistance but also increased reactive oxygen species (ROS) accumulation and cell death. Furthermore, MdERF100-overexpressing Arabidopsis plants exhibited differential expressions of genes involved in jasmonic acid (JA) and salicylic acid (SA) signaling when infected with the powdery mildew pathogen. Additionally, yeast two-hybrid and bimolecular fluorescence complementation assays confirmed that MdERF100 physically interacts with the basic helix–loop–helix (bHLH) protein MdbHLH92. These results suggest that MdERF100 mediates powdery mildew resistance by regulating the JA and SA signaling pathways, and MdbHLH92 is involved in plant defense against powdery mildew. Overall, this study enhances our understanding of the role of MdERF genes in disease resistance, and provides novel insights into the molecular mechanisms of powdery mildew resistance in apple.

scholarly journals VTC4 Polyphosphate Polymerase Knockout Increases Stress Resistance of Saccharomyces cerevisiae Cells

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 487
Author(s):  
Alexander Tomashevsky ◽  
Ekaterina Kulakovskaya ◽  
Ludmila Trilisenko ◽  
Ivan V. Kulakovskiy ◽  
Tatiana Kulakovskaya ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heavy Metal ◽  
Stress Response ◽  
Stress Resistance ◽  
Alkaline Stress ◽  
Inorganic Polyphosphate ◽  
Divalent Metal Transporter ◽  
Metal Transporter ◽  
Elevated Expression ◽  
Chaperone Complex

Inorganic polyphosphate (polyP) is an important factor of alkaline, heavy metal, and oxidative stress resistance in microbial cells. In yeast, polyP is synthesized by Vtc4, a subunit of the vacuole transporter chaperone complex. Here, we report reduced but reliably detectable amounts of acid-soluble and acid-insoluble polyPs in the Δvtc4 strain of Saccharomyces cerevisiae, reaching 10% and 20% of the respective levels of the wild-type strain. The Δvtc4 strain has decreased resistance to alkaline stress but, unexpectedly, increased resistance to oxidation and heavy metal excess. We suggest that increased resistance is achieved through elevated expression of DDR2, which is implicated in stress response, and reduced expression of PHO84 encoding a phosphate and divalent metal transporter. The decreased Mg2+-dependent phosphate accumulation in Δvtc4 cells is consistent with reduced expression of PHO84. We discuss a possible role that polyP level plays in cellular signaling of stress response mobilization in yeast.

scholarly journals Impact of Carcinogenic Chromium on the Cellular Response to Proteotoxic Stress

2019 ◽  
Vol 20 (19) ◽  
pp. 4901 ◽  
Author(s):  
Leonardo M. R. Ferreira ◽  
Teresa Cunha-Oliveira ◽  
Margarida C. Sobral ◽  
Patrícia L. Abreu ◽  
Maria Carmen Alpoim ◽  
...  
Keyword(s):  
Stress Response ◽  
Health Effects ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Chemical Properties ◽  
Adverse Health Effects ◽  
Proteotoxic Stress ◽  
Adverse Health ◽  
The Impact

Worldwide, several million workers are employed in the various chromium (Cr) industries. These workers may suffer from a variety of adverse health effects produced by dusts, mists and fumes containing Cr in the hexavalent oxidation state, Cr(VI). Of major importance, occupational exposure to Cr(VI) compounds has been firmly associated with the development of lung cancer. Counterintuitively, Cr(VI) is mostly unreactive towards most biomolecules, including nucleic acids. However, its intracellular reduction produces several species that react extensively with biomolecules. The diversity and chemical versatility of these species add great complexity to the study of the molecular mechanisms underlying Cr(VI) toxicity and carcinogenicity. As a consequence, these mechanisms are still poorly understood, in spite of intensive research efforts. Here, we discuss the impact of Cr(VI) on the stress response—an intricate cellular system against proteotoxic stress which is increasingly viewed as playing a critical role in carcinogenesis. This discussion is preceded by information regarding applications, chemical properties and adverse health effects of Cr(VI). A summary of our current understanding of cancer initiation, promotion and progression is also provided, followed by a brief description of the stress response and its links to cancer and by an overview of potential molecular mechanisms of Cr(VI) carcinogenicity.

Transcriptional targets of DAF-16 insulin signaling pathway protect C. elegans from extreme hypertonic stress

2005 ◽  
Vol 288 (2) ◽  
pp. C467-C474 ◽  
Author(s):  
S. Todd Lamitina ◽  
Kevin Strange
Keyword(s):  
Insulin Signaling ◽  
Stress Resistance ◽  
Molecular Mechanisms ◽  
Organic Osmolytes ◽  
Dependent Manner ◽  
Animal Cells ◽  
Hypertonic Stress ◽  
C Elegans ◽  
Downstream Target ◽  
Molecular Damage

All cells adapt to hypertonic stress by regulating their volume after shrinkage, by accumulating organic osmolytes, and by activating mechanisms that protect against and repair hypertonicity-induced damage. In mammals and nematodes, inhibition of signaling from the DAF-2/IGF-1 insulin receptor activates the DAF-16/FOXO transcription factor, resulting in increased life span and resistance to some types of stress. We tested the hypothesis that inhibition of insulin signaling in Caenorhabditis elegans also increases hypertonic stress resistance. Genetic inhibition of DAF-2 or its downstream target, the AGE-1 phosphatidylinositol 3-kinase, confers striking resistance to a normally lethal hypertonic shock in a DAF-16-dependent manner. However, insulin signaling is not inhibited by or required for adaptation to hypertonic conditions. Microarray studies have identified 263 genes that are transcriptionally upregulated by DAF-16 activation. We identified 14 DAF-16-upregulated genes by RNA interference screening that are required for age- 1 hypertonic stress resistance. These genes encode heat shock proteins, proteins of unknown function, and trehalose synthesis enzymes. Trehalose levels were elevated approximately twofold in age- 1 mutants, but this increase was insufficient to prevent rapid hypertonic shrinkage. However, age- 1 animals unable to synthesize trehalose survive poorly under hypertonic conditions. We conclude that increased expression of proteins that protect eukaryotic cells against environmental stress and/or repair stress-induced molecular damage confers hypertonic stress resistance in C. elegans daf- 2/ age- 1 mutants. Elevated levels of solutes such as trehalose may also function in a cytoprotective manner. Our studies provide novel insights into stress resistance in animal cells and a foundation for new studies aimed at defining molecular mechanisms underlying these essential processes.

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