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Biomolecules May 2021The mechanistic target of rapamycin (mTOR) is a central regulator of cellular homeostasis that integrates environmental and nutrient signals to control cell growth and... (Review)
Review
The mechanistic target of rapamycin (mTOR) is a central regulator of cellular homeostasis that integrates environmental and nutrient signals to control cell growth and survival. Over the past two decades, extensive studies of mTOR have implicated the importance of this protein complex in regulating a broad range of metabolic functions, as well as its role in the progression of various human diseases. Recently, mTOR has emerged as a key signaling molecule in regulating animal entry into a hypometabolic state as a survival strategy in response to environmental stress. Here, we review current knowledge of the role that mTOR plays in contributing to natural hypometabolic states such as hibernation, estivation, hypoxia/anoxia tolerance, and dauer diapause. Studies across a diverse range of animal species reveal that mTOR exhibits unique regulatory patterns in an environmental stressor-dependent manner. We discuss how key signaling proteins within the mTOR signaling pathways are regulated in different animal models of stress, and describe how each of these regulations uniquely contribute to promoting animal survival in a hypometabolic state.
Topics: Adaptation, Physiological; Animals; Cell Cycle; Cell Proliferation; Diapause; Estivation; Hibernation; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Signal Transduction; Stress, Physiological; TOR Serine-Threonine Kinases
PubMed: 34062764
DOI: 10.3390/biom11050681 -
Frontiers in Physiology 2022Long-term estivation (45 days) in the apple snail induces an increase of non-enzymatic antioxidants, such as uric acid and reduced glutathione (GSH), which...
Long-term estivation (45 days) in the apple snail induces an increase of non-enzymatic antioxidants, such as uric acid and reduced glutathione (GSH), which constitutes an alternative to the adaptive physiological strategy of preparation for oxidative stress (POS). Here, we studied markers of oxidative stress damage, uric acid levels, and non-enzymatic antioxidant capacity, enzymatic antioxidant defenses, such as superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST), and transcription factors expression [forkhead box protein O (FOXO), hypoxia-inducible factor-1 alpha (HIF1α), and nuclear factor erythroid 2-related factor 2 (Nrf2)] in control active animals, 7-day estivating and aroused snails, in digestive gland, gill, and lung tissue samples. In the digestive gland, SOD and CAT activities significantly increased after estivation and decreased during arousal. Meanwhile, GST activity decreased significantly during the activity-estivation-arousal cycle. Gill CAT activity increased significantly at 7 days of estivation, and it decreased during arousal. In the lung, the CAT activity level increased significantly during the cycle. FOXO upregulation was observed in the studied tissues, decreasing its expression only in the gill of aroused animals during the cycle. HIF1α and Nrf2 transcription factors decreased their expression during estivation in the gill, while in the lung and the digestive gland, both transcription factors did not show significant changes. Our results showed that the short-term estivation induced oxidative stress in different tissues of thereby increasing overall antioxidant enzymes activity and highlighting the role of FOXO regulation as a possible underlying mechanism of the POS strategy.
PubMed: 35185614
DOI: 10.3389/fphys.2022.805168 -
Journal of Experimental Stroke &... Jan 2012Although therapeutic hypothermia and metabolic suppression have shown robust neuroprotection in experimental brain ischemia, systemic complications have limited their...
Although therapeutic hypothermia and metabolic suppression have shown robust neuroprotection in experimental brain ischemia, systemic complications have limited their use in treating acute stroke patients. The core temperature and basic metabolic rate are tightly regulated and maintained in a very stable level in mammals. Simply lowering body temperature or metabolic rate is actually a brutal therapy that may cause more systemic as well as regional problems other than providing protection. These problems are commonly seen in hypothermia and barbiturate coma. The main innovative concept of this review is to propose thermogenically optimal and synergistic reduction of core temperature and metabolic rate in therapeutic hypometabothermia using novel and clinically practical approaches. When metabolism and body temperature are reduced in a systematically synergistic manner, the outcome will be maximal protection and safe recovery, which happen in natural process, such as in hibernation, daily torpor and estivation.
PubMed: 24179563
DOI: 10.6030/1939-067x-5.1.31 -
Cell Stress & Chaperones Sep 2023Chaperone proteins have crucial roles to play in all animal species and are involved in mediating both the folding of newly synthesized peptides into their mature... (Review)
Review
Chaperone proteins have crucial roles to play in all animal species and are involved in mediating both the folding of newly synthesized peptides into their mature conformation, the refolding of misfolded proteins, and the trafficking of proteins between subcellular compartments. These highly conserved proteins have particularly important roles to play in dealing with disruptions of the proteome as a result of environmental stress since abiotic factors, including temperature, pressure, oxygen, water availability, and pollutants can readily disrupt the conformation and/or function of all types of proteins, e.g., enzymes, transporters, and structural proteins. The current review provides an update on recent advances in understanding the roles and responses of chaperones in aiding animals to deal with environmental stress, offering new information on chaperone action in supporting survival strategies including torpor, hibernation, anaerobiosis, estivation, and cold/freeze tolerance among both vertebrate and invertebrate species.
Topics: Animals; Heat-Shock Proteins; Molecular Chaperones; Protein Folding; Cold Temperature; Temperature
PubMed: 36441380
DOI: 10.1007/s12192-022-01312-x -
Metabolites Feb 2023States of natural dormancy include estivation and hibernation. Ampullariids are exemplary because they undergo estivation when deprived of water or hibernation when...
States of natural dormancy include estivation and hibernation. Ampullariids are exemplary because they undergo estivation when deprived of water or hibernation when exposed to very low temperatures. Regardless of the condition, ampullariids show increased endogenous antioxidant defenses, anticipating the expected respiratory burst during reoxygenation after reactivation, known as "Preparation for Oxidative Stress (POS)". In this work, we tested the POS hypothesis for changes in the blood and hemocytes of the bimodal breather (Ampullariidae) induced at experimental estivation and hibernation. We described respiratory (hemocyanin, proteins, lactate), antioxidant (GSH, uric acid, SOD, CAT, GST), and immunological (hemocyte levels, ROS production) parameters. We showed that, although the protein level remains unchanged in all experimental groups, hemocyanin increases in response to estivation. Furthermore, lactate remains unchanged in challenged snails, suggesting an aerobic metabolism during short-term challenges. Blood uric acid increases during estivation and arousal from estivation or hibernation, supporting the previously proposed antioxidant role. Regarding hemocytes, we showed that the total population increases with all challenges, and granulocytes increase during hibernation. We further showed that hibernation affects ROS production by hemocytes, possibly through mitochondrial inhibition. This study contributed to the knowledge of the adaptive strategies of ampullariids to tolerate adverse environmental conditions.
PubMed: 36837908
DOI: 10.3390/metabo13020289 -
Frontiers in Physiology 2022Diapause is a physiological adaptation to conditions that are unfavorable for growth or reproduction. During diapause, animals become long-lived, stress-resistant,... (Review)
Review
Diapause is a physiological adaptation to conditions that are unfavorable for growth or reproduction. During diapause, animals become long-lived, stress-resistant, developmentally static, and non-reproductive, in the case of diapausing adults. Diapause has been observed at all developmental stages in both vertebrates and invertebrates. In adults, diapause traits weaken into adaptations such as hibernation, estivation, dormancy, or torpor, which represent evolutionarily diverse versions of the traditional diapause traits. These traits are regulated through modifications of the endocrine program guiding development. In insects, this typically includes changes in molting hormones, as well as metabolic signals that limit growth while skewing the organism's energetic demands toward conservation. While much work has been done to characterize these modifications, the interactions between hormones and their downstream consequences are incompletely understood. The current state of diapause endocrinology is reviewed here to highlight the relevance of diapause beyond its use as a model to study seasonality and development. Specifically, insect diapause is an emerging model to study mechanisms that determine lifespan. The induction of diapause represents a dramatic change in the normal progression of age. Hormones such as juvenile hormone, 20-hydroxyecdysone, and prothoracicotropic hormone are well-known to modulate this plasticity. The induction of diapause-and by extension, the cessation of normal aging-is coordinated by interactions between these pathways. However, research directly connecting diapause endocrinology to the biology of aging is lacking. This review explores connections between diapause and aging through the perspective of endocrine signaling. The current state of research in both fields suggests appreciable overlap that will greatly contribute to our understanding of diapause and lifespan determination.
PubMed: 35242054
DOI: 10.3389/fphys.2022.825057 -
American Journal of Hypertension Aug 2020Salt (NaCl) is a prerequisite for life. Excessive intake of salt, however, is said to increase disease risk, including hypertension, arteriosclerosis, heart failure,... (Review)
Review
Salt (NaCl) is a prerequisite for life. Excessive intake of salt, however, is said to increase disease risk, including hypertension, arteriosclerosis, heart failure, renal disease, stroke, and cancer. Therefore, considerable research has been expended on the mechanism of sodium handling based on the current concepts of sodium balance. The studies have necessarily relied on relatively short-term experiments and focused on extremes of salt intake in humans. Ultra-long-term salt balance has received far less attention. We performed long-term salt balance studies at intakes of 6, 9, and 12 g/day and found that although the kidney remains the long-term excretory gate, tissue and plasma sodium concentrations are not necessarily the same and that urinary salt excretion does not necessarily reflect total-body salt content. We found that to excrete salt, the body makes a great effort to conserve water, resulting in a natriuretic-ureotelic principle of salt excretion. Of note, renal sodium handling is characterized by osmolyte excretion with anti-parallel water reabsorption, a state-of-affairs that is achieved through the interaction of multiple organs. In this review, we discuss novel sodium and water balance concepts in reference to our ultra-long-term study. An important key to understanding body sodium metabolism is to focus on water conservation, a biological principle to protect from dehydration, since excess dietary salt excretion into the urine predisposes to renal water loss because of natriuresis. We believe that our research direction is relevant not only to salt balance but also to cardiovascular regulatory mechanisms.
Topics: Animals; Appetite; Body Water; Cardiovascular System; Drinking; Energy Metabolism; Humans; Infradian Rhythm; Kidney; Kidney Concentrating Ability; Liver; Muscle, Skeletal; Natriuresis; Renal Elimination; Sodium; Sodium Chloride, Dietary; Thirst; Water-Electrolyte Balance
PubMed: 32198504
DOI: 10.1093/ajh/hpaa049 -
Frontiers in Behavioral Neuroscience 2016The nocturnal Bogong moth (Agrotis infusa) is an iconic and well-known Australian insect that is also a remarkable nocturnal navigator. Like the Monarch butterflies of... (Review)
Review
The nocturnal Bogong moth (Agrotis infusa) is an iconic and well-known Australian insect that is also a remarkable nocturnal navigator. Like the Monarch butterflies of North America, Bogong moths make a yearly migration over enormous distances, from southern Queensland, western and northwestern New South Wales (NSW) and western Victoria, to the alpine regions of NSW and Victoria. After emerging from their pupae in early spring, adult Bogong moths embark on a long nocturnal journey towards the Australian Alps, a journey that can take many days or even weeks and cover over 1000 km. Once in the Alps (from the end of September), Bogong moths seek out the shelter of selected and isolated high ridge-top caves and rock crevices (typically at elevations above 1800 m). In hundreds of thousands, moths line the interior walls of these cool alpine caves where they "hibernate" over the summer months (referred to as "estivation"). Towards the end of the summer (February and March), the same individuals that arrived months earlier leave the caves and begin their long return trip to their breeding grounds. Once there, moths mate, lay eggs and die. The moths that hatch in the following spring then repeat the migratory cycle afresh. Despite having had no previous experience of the migratory route, these moths find their way to the Alps and locate their estivation caves that are dotted along the high alpine ridges of southeastern Australia. How naïve moths manage this remarkable migratory feat still remains a mystery, although there are many potential sensory cues along the migratory route that moths might rely on during their journey, including visual, olfactory, mechanical and magnetic cues. Here we review our current knowledge of the Bogong moth, including its natural history, its ecology, its cultural importance to the Australian Aborigines and what we understand about the sensory basis of its long-distance nocturnal migration. From this analysis it becomes clear that the Bogong moth represents a new and very promising model organism for understanding the sensory basis of nocturnal migration in insects.
PubMed: 27147998
DOI: 10.3389/fnbeh.2016.00077 -
Frontiers in Physiology 2022
PubMed: 35547571
DOI: 10.3389/fphys.2022.904746 -
EFSA Journal. European Food Safety... Jul 2020The EFSA Panel on Plant Health performed a pest categorisation of (Lepidoptera: Noctuidae) (American cotton bollworm, corn earworm) for the EU. is a polyphagous...
The EFSA Panel on Plant Health performed a pest categorisation of (Lepidoptera: Noctuidae) (American cotton bollworm, corn earworm) for the EU. is a polyphagous species that feeds on over 100 plant species. The crops most frequently recorded as host plants are maize, sorghum, cotton, beans, peas, chickpeas, tomatoes, aubergines, peppers and, to a lesser extent, clover, okra, cabbages, lettuces, strawberries, tobacco, sunflowers, cucurbits and ornamentals. preferentially feeds on flowers and fruits of the host. Eggs are laid mostly on maize silks. Larvae feed on the silks and kernels. Pupation takes place in the soil. Hibernation and estivation as pupa are reported. Adults are nocturnal. is a strong flier, able to fly up to 400 km during migration. Commission Implementing Regulation (EU) 2019/2072 (Annex IIA) regulates . Fruits and plants for planting, with and without soil, provide potential pathways for entry into the EU. Climatic conditions and the availability of host plants provide conditions to support establishment in the EU. The introduction of could have an economic impact in the EU through qualitative and quantitative effects on agricultural production (e.g. tomatoes, soybean, sweet corn). Phytosanitary measures are available to reduce the likelihood of entry. satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. does not meet the criteria of (a) occurring in the EU, and (b) plants for planting being the principal means of spread for it to satisfy the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union regulated non-quarantine pest.
PubMed: 32665793
DOI: 10.2903/j.efsa.2020.6177