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WormBook : the Online Review of C.... Aug 2018Dauer diapause is a stress-resistant, developmentally quiescent, and long-lived larval stage adopted by Caenorhabditis elegans when conditions are unfavorable for growth... (Review)
Review
Dauer diapause is a stress-resistant, developmentally quiescent, and long-lived larval stage adopted by Caenorhabditis elegans when conditions are unfavorable for growth and reproduction. This chapter contains methods to induce dauer larva formation, to isolate dauer larvae, and to study pre- and post-dauer stages.
Topics: Animals; Caenorhabditis elegans; Diapause; Larva
PubMed: 27417559
DOI: 10.1895/wormbook.1.180.1 -
Biology of Reproduction Jul 2018The first incidence of embryonic diapause in mammals was observed in the roe deer, Capreolus capreolus, in 1854 and confirmed in the early 1900s. Since then scientists... (Review)
Review
The first incidence of embryonic diapause in mammals was observed in the roe deer, Capreolus capreolus, in 1854 and confirmed in the early 1900s. Since then scientists have been fascinated by this phenomenon that allows a growing embryo to become arrested for up to 11 months and then reactivate and continue development with no ill effects. The study of diapause has required unraveling basic reproductive processes we now take for granted and has spanned some of the major checkpoints of reproductive biology from the identification of the sex hormones to the hypothalamic-pituitary axis to microRNA and exosomes. This review will describe the history of diapause from its origins to the current day, including its discovery and efforts to elucidate its mechanisms. It will also attempt to highlight the people involved who were instrumental in progressing this field over the last 160 years. The most recent confirmation of mammalian diapause was in the panda in 2009 and there are still multiple mammals where it has been predicted but not yet confirmed. Furthermore, there are many questions still unanswered which ensure that embryonic diapause will continue to be a topic of research for many years to come. Note that there have recently been several extensive reviews covering the recent advances in embryonic diapause, so they will be mentioned only briefly here. For further information refer to Renfree and Shaw 2014; Fenelon et al 2014; Renfree and Fenelon 2017, and references therein.
Topics: Animals; Diapause; Embryo Implantation, Delayed; Embryonic Development; Female; History, 19th Century; History, 20th Century; History, 21st Century; Mammals; Research; Uterus
PubMed: 29741586
DOI: 10.1093/biolre/ioy112 -
Challenges during diapause and anhydrobiosis: Mitochondrial bioenergetics and desiccation tolerance.IUBMB Life Dec 2018In preparation for the onset of environmental challenges like overwintering, food limitation, anoxia, or water stress, many invertebrates and certain killifish enter... (Review)
Review
In preparation for the onset of environmental challenges like overwintering, food limitation, anoxia, or water stress, many invertebrates and certain killifish enter diapause. Diapause is a developmentally-programed dormancy characterized by suppression of development and metabolism. For embryos of Artemia franciscana (brine shrimp), the metabolic arrest is profound. These gastrula-stage embryos depress oxidative metabolism by ~99% during diapause and survive years of severe desiccation in a state termed anhydrobiosis. Trehalose is the sole fuel source for this developmental stage. Mitochondrial function during diapause is downregulated primarily by restricting substrate supply, as a result of inhibiting key enzymes of carbohydrate metabolism. Because proton conductance across the inner membrane is not decreased during diapause, the inference is that membrane potential must be compromised. In the absence of any intervention, the possibility exists that the F F ATP synthase and the adenine nucleotide translocator may reverse, leading to wholesale hydrolysis of cellular ATP. Studies with anhydrobiotes like A. franciscana are revealing multiple traits useful for improving desiccation tolerance that include the expression and accumulation late embryogenesis abundant (LEA) proteins and trehalose. LEA proteins are intrinsically disordered in aqueous solution but gain secondary structure (predominantly α-helix) as water is removed. These protective agents stabilize biological structures including lipid bilayers and mitochondria during severe water stress. © 2018 IUBMB Life, 70(12):1251-1259, 2018.
Topics: Adaptation, Physiological; Animals; Artemia; Dehydration; Diapause; Embryo, Nonmammalian; Embryonic Development; Energy Metabolism; Fundulidae; Mitochondria; Trehalose
PubMed: 30369011
DOI: 10.1002/iub.1953 -
Animal Reproduction Science Nov 2018Embryonic diapause occurs in over 130 species of mammals. In embryonic diapause, there is a reversible cessation phase in embryo development and subsequent reactivation... (Review)
Review
Embryonic diapause occurs in over 130 species of mammals. In embryonic diapause, there is a reversible cessation phase in embryo development and subsequent reactivation and continuation of development with no adverse effects. This allows animals to prolong gestation and give birth to offspring at a more favorable time from a survival perspective. Embryonic diapause is divided into two types: facultative diapause which is induced by physiological conditions and obligate diapause which is induced by season of the year. The process of embryonic diapause includes three phases: onset, maintenance, and reactivation. With facultative diapause the suckling stimulus promotes secretion of prolactin, which suppresses development and secretion activity of the corpus luteum (CL). The decrease of progesterone, secreted by CL, subsequently results in embryos in the diapause state. The embryonic diapause that occurs in mink is of the obligate type and is regulated by photoperiod. The short daylight (<12 h) before the vernal equinox induces an increase in the release of melatonin from the pineal gland. The secretion of prolactin is suppressed and the production of progesterone from CL is reduced. During these phases, many others factors that regulate embryonic and uterine status, hormonal profile, polyamines, and uterine secretion, have been monitored. In recent times, the understanding of the role of different molecular events in embryonic diapause has been advanced. The present review summarizes the research advances related to embryonic diapause to enhance the understanding of this phenomenon and to be considered when there are future research endeavors related to embryonic diapause.
Topics: Animals; Diapause; Embryo, Mammalian; Embryonic Development; Female; Humans; Mammals; Pregnancy
PubMed: 30266523
DOI: 10.1016/j.anireprosci.2018.09.009 -
The Journal of Comparative Neurology Oct 2023Insects from high latitudes spend the winter in a state of overwintering diapause, which is characterized by arrested reproduction, reduced food intake and metabolism,...
Insects from high latitudes spend the winter in a state of overwintering diapause, which is characterized by arrested reproduction, reduced food intake and metabolism, and increased life span. The main trigger to enter diapause is the decreasing day length in summer-autumn. It is thus assumed that the circadian clock acts as an internal sensor for measuring photoperiod and orchestrates appropriate seasonal changes in physiology and metabolism through various neurohormones. However, little is known about the neuronal organization of the circadian clock network and the neurosecretory system that controls diapause in high-latitude insects. We addressed this here by mapping the expression of clock proteins and neuropeptides/neurohormones in the high-latitude fly Drosophila littoralis. We found that the principal organization of both systems is similar to that in Drosophila melanogaster, but with some striking differences in neuropeptide expression levels and patterns. The small ventrolateral clock neurons that express pigment-dispersing factor (PDF) and short neuropeptide F (sNPF) and are most important for robust circadian rhythmicity in D. melanogaster virtually lack PDF and sNPF expression in D. littoralis. In contrast, dorsolateral clock neurons that express ion transport peptide in D. melanogaster additionally express allatostatin-C and appear suited to transfer day-length information to the neurosecretory system of D. littoralis. The lateral neurosecretory cells of D. littoralis contain more neuropeptides than D. melanogaster. Among them, the cells that coexpress corazonin, PDF, and diuretic hormone 44 appear most suited to control diapause. Our work sets the stage to investigate the roles of these diverse neuropeptides in regulating insect diapause.
Topics: Animals; Drosophila; Drosophila melanogaster; CLOCK Proteins; Circadian Rhythm; Diapause; Circadian Clocks; Neuropeptides; Drosophila Proteins
PubMed: 37493077
DOI: 10.1002/cne.25522 -
Developmental ecology of annual killifish Millerichthys robustus (Cyprinodontiformes: Cynolebiidae).Developmental Dynamics : An Official... Nov 2017Populations of annual killifishes persist in temporary water bodies over the dry season through the expression of diapause in their drought-resistant embryos.... (Review)
Review
Populations of annual killifishes persist in temporary water bodies over the dry season through the expression of diapause in their drought-resistant embryos. Environmental cues may influence expression of the diapause phenotype during embryonic incubation. Millerichthys robustus is the only annual killifish distributed in North America. The aim of this review is to analyze the ecology of M. robustus development and contrast this with that of annual killifishes in austral locations. The temporary water bodies inhabited by M. robustus present the following environmental conditions: flood, drought, and humidity. During the flooding period, the environment presents the lowest temperatures, shortest photoperiod, and highest precipitation, and embryos were found in diapause I. The drought period features the highest temperatures and lowest precipitation, and embryos were found in diapause II. In contrast, during the humid period at the beginning of the rainy season, embryos were found in diapause I, II, and III, associated with the longer photoperiod and high temperatures. These dynamics of the diapause phenotypes can be explained by a combination of the strategies of phenotypic plasticity during flood and drought periods, and bet-hedging during the humid period. Moreover, the microenvironmental conditions in which embryos were buried could influence developmental trajectories. Developmental Dynamics 246:802-806, 2017. © 2017 Wiley Periodicals, Inc.
Topics: Adaptation, Physiological; Animals; Cyprinodontiformes; Diapause; Droughts; Ecological Systems, Closed; Embryo, Nonmammalian; Floods; Humidity; Killifishes
PubMed: 28493325
DOI: 10.1002/dvdy.24519 -
Current Opinion in Insect Science Dec 2019Diapause in response to seasonality is an important model for rapid evolutionary adaptation that is highly genetically variable, and experiences strong natural... (Review)
Review
Diapause in response to seasonality is an important model for rapid evolutionary adaptation that is highly genetically variable, and experiences strong natural selection. Forward genetic methods using various genomic and transcriptomic approaches have begun to characterize the genetic architecture and candidate genes underlying diapause evolution. Largely in parallel, reverse genetic studies have identified functional roles for candidate genes that may or may not be genetically variable. We illustrate the disconnect between the evolutionary and physiological literature using a suite of studies of the role of the circadian clock in diapause regulation. These extensive studies in two different disciplines provide excellent opportunities for integration, which should facilitate rapid progress in understanding both the regulation and evolution of diapause.
Topics: Animals; Biological Evolution; Circadian Clocks; Diapause, Insect; Insecta; Seasons
PubMed: 31539788
DOI: 10.1016/j.cois.2019.08.003 -
Annual Review of Entomology 2016Plastic responses figure prominently in discussions on insect adaptation to climate change. Here we review the different types of plastic responses and whether they... (Review)
Review
Plastic responses figure prominently in discussions on insect adaptation to climate change. Here we review the different types of plastic responses and whether they contribute much to adaptation. Under climate change, plastic responses involving diapause are often critical for population persistence, but key diapause responses under dry and hot conditions remain poorly understood. Climate variability can impose large fitness costs on insects showing diapause and other life cycle responses, threatening population persistence. In response to stressful climatic conditions, insects also undergo ontogenetic changes including hardening and acclimation. Environmental conditions experienced across developmental stages or by prior generations can influence hardening and acclimation, although evidence for the latter remains weak. Costs and constraints influence patterns of plasticity across insect clades, but they are poorly understood within field contexts. Plastic responses and their evolution should be considered when predicting vulnerability to climate change-but meaningful empirical data lag behind theory.
Topics: Adaptation, Biological; Animals; Biological Evolution; Climate Change; Diapause, Insect; Environment; Insecta; Metamorphosis, Biological
PubMed: 26667379
DOI: 10.1146/annurev-ento-010715-023859 -
Journal of Insect Physiology Apr 2023Low temperatures associated with winter can limit the survival of organisms, especially ectotherms whose body temperature is similar to their environment. However, there...
Low temperatures associated with winter can limit the survival of organisms, especially ectotherms whose body temperature is similar to their environment. However, there is a gap in understanding how overwintering may vary among groups of species that interact closely, such as multiple parasitoid species that attack the same host insect. Here, we investigate cold tolerance and diapause phenotypes in three endoparasitoid wasps of the apple maggot fly Rhagoletis pomonella (Diptera: Tephritidae): Utetes canaliculatus, Diachasma alloeum, and Diachasmimorpha mellea (Hymenoptera: Braconidae). Using a combination of respirometry and eclosion tracking, we found that all three wasp species exhibited the same three diapause duration phenotypes as the fly host. Weak (short duration) diapause was rare, with <5 % of all three wasp species prematurely terminating diapause at 21 °C. Most D.mellea (93 %) entered a more intense (longer duration) diapause that did not terminate within 100 d at this warm temperature. The majority of U.canaliculatus (92 %) and D. alloeum (72 %) averted diapause (non-diapause) at 21 °C. There was limited interspecific variation in acute cold tolerance among the three wasp species: wasps and flies had similarly high survival (>87 %) following exposure to extreme low temperatures (-20 °C) as long as their body fluids did not freeze. The three wasp species also displayed little interspecific variation in survival following prolonged exposure to mild chilling of 8 or more weeks at 4 °C. Our study thus documents a remarkable conservation of cold tolerance and diapause phenotypes within and across trophic levels.
Topics: Animals; Wasps; Diapause, Insect; Larva; Cold Temperature; Tephritidae
PubMed: 36921838
DOI: 10.1016/j.jinsphys.2023.104501 -
Journal of Insect Physiology Mar 2023Many insects enter a dormant state termed diapause in anticipation of seasonal inhospitable conditions. Insects drastically reduce their feeding during diapause. Their... (Review)
Review
Many insects enter a dormant state termed diapause in anticipation of seasonal inhospitable conditions. Insects drastically reduce their feeding during diapause. Their reduced nutrient intake is paired with substantial nutrient costs: maintaining basal metabolism during diapause, repairing tissues damaged by adverse conditions, and resuming development after diapause. Many investigators have asked "Does nutrition affect diapause?" In this review, we survey the studies that have attempted to address this question. We propose the term nutritional status, a holistic view of nutrition that explicitly includes the perception, intake, and storage of the great breadth of nutrients. We examine the studies that have sought to test if nutrition affects diapause, trying to identify specific facets of nutritional status that affect diapause phenotypes. Curiously, low quality host plants during the diapause induction phase generally induce diapause, but food deprivation during the same phase generally averts diapause. Using the geometric framework of nutrition to identify specific dietary components that affect diapause may reconcile these contrasting findings. This framework can establish nutritionally permissive space, distinguishing nutrient changes that affect diapause from changes that induce other dormancies. Refeeding is another important experimental technique that distinguishes between diapause and quiescence, a non-diapause dormancy. We also find insufficient evidence for the hypothesis that nutrient stores regulate diapause length and suggest manipulations to investigate the role of nutrient stores in diapause termination. Finally, we propose mechanisms that could interface nutritional status with the diapause program, focusing on combined action of the nutritional axis between the gut, fat body, and brain.
Topics: Animals; Seasons; Nutritional Status; Diapause, Insect; Diapause; Insecta
PubMed: 36717056
DOI: 10.1016/j.jinsphys.2023.104488