Search

The bogong moth, Agrotis infusa, an endemic noctuid moth of Australia, is known for its extensive long‐distance movement and summer aestivation in the Australian Alps. Recent studies have focused on moth activity in the Alps, but there are limited data for other regions. This study aims to build on the current understanding of bogong moth movement and breeding patterns using unpublished historical data across eastern Australia. We analysed historical data from moth traps in Victoria, New South Wales (NSW) and South Australia (SA) from the 1960s to early 1990s. The study employed the HYSPLIT model for trajectory analysis of moth flight paths and DARABUG2 for phenological modelling. We examined moth catches across different seasons to infer movement patterns, breeding sources and over‐summering activity. Our findings question several long‐standing assumptions about the spatial ecology of the bogong moth. The trajectory analysis suggests that many aspects of A. infusa movement can be explained via dynamic migration, without fully relying on inherent navigation abilities. Important breeding areas may be beyond the self‐mulching clays of NSW and southern Queensland and include far western NSW, south and central SA and southern Victoria. Substantial moth activity during summer in many traps suggests alternative over‐summering strategies including local breeding or even aestivation in areas other than the Alps. Furthermore, the autumn and winter data imply return migrations from diverse source areas and potential local breeding, expanding the understanding of the moth's life cycle beyond a univoltine pattern. In conclusion, the bogong moth appears to exhibit a more complex and adaptable migration and breeding strategy than previously understood, utilising a range of habitats across eastern Australia for breeding and possibly aestivation. This underscores the need for a revised understanding of bogong moth ecology, which is crucial for its conservation and management, especially considering its recent classification as ‘Endangered’ on the IUCN Red List. [ABSTRACT FROM AUTHOR]

This research focused on the annual activities, including aestivation, hibernation and reproductive behaviours, of the endemic species Helix salomonica Nägele, 1899 in its natural habitat in Şırnak, Turkey. Within an area of 900 m2, a population of at least 600 snails was monitored for a year. Eighty snail specimens were sampled and measured, with twenty of them observed in a laboratory environment (within a cage) for comparison of circannual snail rhythms. The annual activity patterns of H. salomonica revealed distinctive behaviours. The total hibernation period lasted around 85 days on average, with continuous hibernation lasting approximately 57 days and intermittent hibernation lasting about 28 days. In March and November, copulation occurs. Durıng the sprıng,the average number of eggs was 63, with an average diameter of 2.85 mm and a weight of 0.28 g. On average, eggs hatched after 34 days, during the second and third weeks of May. Aestivation persisted continuously from late May to early November, averaging 165 days. Arousal and the observation of juvenile snails coincided in the second week of November. Consequently, the annual activity cycles of H. salomonica are intricately regulated by a complex interplay of internal (endogenous) rhythms and external factors, with dormancy phases predominantly governed by circannual rhythms. [ABSTRACT FROM AUTHOR]

The stability of host plant resistance to insects, and efficacy of insecticides against the insect pests is influenced by several inherent traits of the target insects in addition to the environmental factors. Spotted stem borer, Chilo partellus (Swinhoe) is a key pest of maize and sorghum. It undergoes both hibernation and aestivation depending upon the prevailing climatic conditions. We studied the host preference and damage potential of this pest in maize and sorghum, and its susceptibility to different insecticides in F1 progenies of hibernating, aestivating and nondiapausing strains of C. partellus. The larvae from hibernating strain resulted in greater leaf damage and deadhearts, and had greater larval weight and better survival on maize and sorghum than those from the aestivating and nondiapausing strains, although there were a few exceptions. The susceptible maize and sorghum genotypes were highly preferred by the hibernating larvae, while the resistant genotypes were preferred most by the aestivating strain. Maize was least preferred, while sorghum was most preferred by the larvae from hibernating as compared to aestivating and nondiapausing strains of C. partellus. The larvae from aestivating strain were least susceptible to cypermethrin and thiamethoxam, but highly susceptible to deltamethrin and imidacloprid as compared to the other strains. The present studies showed significant differences in preference and damage potential in the host crops, and susceptibility to insecticides in diapausing and nondiapausing strains of C. partellus. Identification of stem borer resistant genotypes of sorghum and maize, and the insecticides with stable efficacy will be useful for integrated management of this pest. [ABSTRACT FROM AUTHOR]

Hypertonic dehydration is associated with muscle wasting and synthesis of organic osmolytes. We recently showed a metabolic shift to amino acid production and urea cycle activation in coronavirus-2019 (COVID-19), consistent with the aestivation response. The aim of the present investigation was to validate the metabolic shift and development of long-term physical outcomes in the non-COVID cohort of the Biobanque Québécoise de la COVID-19 (BQC19). We included 824 patients from BQC19, where 571 patients had data of dehydration in the form of estimated osmolality (eOSM = 2Na + 2K + glucose + urea), and 284 patients had metabolome data and long-term follow-up. We correlated the degree of dehydration to mortality, invasive mechanical ventilation, acute kidney injury, and long-term symptoms. As found in the COVID cohort, higher eOSM correlated with a higher proportion of urea and glucose of total eOSM, and an enrichment of amino acids compared with other metabolites. Sex-stratified analysis indicated that women may show a weaker aestivation response. More severe dehydration was associated with mortality, invasive mechanical ventilation, and acute kidney injury during the acute illness. Importantly, more severe dehydration was associated with physical long-term symptoms but not mental long-term symptoms after adjustment for age, sex, and disease severity. Patients with water deficit in the form of increased eOSM tend to have more severe disease and experience more physical symptoms after an acute episode of care. This is associated with amino acid and urea production, indicating dehydration-induced muscle wasting. NEW & NOTEWORTHY: We have previously shown that humans exhibit an aestivation-like response where dehydration leads to a metabolic shift to urea synthesis, which is associated with long-term weakness indicating muscle wasting. In the present study, we validate this response in a new cohort and present a deeper metabolomic analysis and pathway analysis. Finally, we present a sex-stratified analysis suggesting weaker aestivation in women. However, women show less dehydration, so the association warrants further study. [ABSTRACT FROM AUTHOR]

Sea cucumber Apostichopus japonicus is an ideal model organism for marine invertebrate aestivation; it annually enters a "sleeping state" for nearly 3 months when ambient water temperature range is 25–30 °C. The natural fasting is accompanied by remodeling the intestinal biota and function, which is a part of host biology and could affect the gut microbiota. We investigatesd the impact of annual aestivation on gut microbiota using high-throughput sequencing of 16S rRNA amplicons. Results reveal a notable alteration in the composition of gut bacteria during aestivation during which various indigenous families and genera that exhibit a preference for dietary glycans (e.g., family Rhodobacteraceae and Flavobacteriaceae) decreased, while the taxa capable of utilizing substrates derived from the host (e.g., genus Akkermansia and Prevotella) increased, and so did certain opportunistic pathogenic bacteria. Moreover, the investigation delved into the gut morphology and immunity response of A. japonicus and reveal that the intestine of A. japonicus undergoes substantial atrophy and degeneration during aestivation. However, there was an observed augmentation in the levels of acid and neutral mucin within mucous cells, as well as an enhanced immune defense response (as evidenced by increased gene expression of AjTLR3, LITAF, Ajp105, and LYZ). These results imply that the composition of sea cucumber gut microbiota differed between aestivation and active periods, which potentially affects the intestinal functions of the host and the symbiotic relationship between host and its microbiota over the active-aestivation cycle. [ABSTRACT FROM AUTHOR]

Diapause, a form of dormancy to delay or halt the reproductive development during unfavourable seasons, has evolved in many insect species. One example is aestivation, an adult‐stage diapause enhancing malaria vectors' survival during the dry season (DS) and their re‐establishment in the next rainy season (RS). This work develops a novel genetic approach to estimate the number or proportion of individuals undergoing diapause, as well as the breeding sizes of the two seasons, using signals from temporal allele frequency dynamics. Our modelling shows the magnitude of drift is dampened at early RS when previously aestivating individuals reappear. Aestivation severely biases the temporal effective population size (Ne$$ {N}_e $$), leading to overestimation of the DS breeding size by 1/1−α2$$ 1/{\left(1‐\alpha \right)}^2 $$ across 1 year, where α$$ \alpha $$ is the aestivating proportion. We find sampling breeding individuals in three consecutive seasons starting from an RS is sufficient for parameter estimation, and perform extensive simulations to verify our derivations. This method does not require sampling individuals in the dormant state, the biggest challenge in most studies. We illustrate the method by applying it to a published data set for Anopheles coluzzii mosquitoes from Thierola, Mali. Our method and the expected evolutionary implications are applicable to any species in which a fraction of the population diapauses for more than one generation, and are difficult or impossible to sample during that stage. [ABSTRACT FROM AUTHOR]

BACKGROUND: Semi‐natural habitats are generally considered to be beneficial to natural enemies of crop pests and pollinators. However, they could also be used by pests, such as the Cabbage Stem Flea Beetle (CSFB), Psylliodes chrysocephala, a major pest of winter oilseed rape, Brassica napus. Adults emerge from pupation in late spring and move to aestivation habitats. Published reports identify forest edges as the major shelter used, but flower strips may also constitute an alternative habitat. This study aimed to: (i) determine the role of perennial flower strips in CSFB aestivation in comparison with woodland edges; (ii) determine the influence of landscape composition on the abundance of aestivating CSFB and (iii) identify the characteristics of the local habitat associated with a high abundance of aestivating CSFB. RESULTS: CSFB emergence from aestivation was monitored with emergence traps from mid‐August to mid‐October 2021, at 14 sites in France. We found that CSFB preferred woodland edges and did not aestivate in flower strips. We found a negative effect of percentage woodland cover only for the smallest scale studied (250 m radius). We also found positive effects of the percentage of litter and mean tree circumference on the number of aestivating CSFB in woodland edges. CONCLUSION: The aestivation of CSFB is supported by woodland edges, but not by flower strips. This implies that the presence of flower strips near oilseed rape fields does not exacerbate the problems due to this pest. However, the crops in the vicinity of woodlands could be colonized earlier by this pest than more distant fields. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Sodium-glucose cotransporter 2 inhibitors are believed to improve cardiac outcomes due to their osmotic diuretic potential. The goal of this study was to test the hypothesis that vasopressin-driven urine concentration overrides the osmotic diuretic effect of glucosuria induced by dapagliflozin treatment. DAPA-Shuttle1 (Hepato-renal Regulation of Water Conservation in Heart Failure Patients With SGLT-2 Inhibitor Treatment) was a single-center, double-blind, randomized, placebo-controlled trial, in which patients with chronic heart failure NYHA functional classes I/II and reduced ejection fraction were randomly assigned to receive dapagliflozin 10 mg daily or placebo (1:1) for 4 weeks. The primary endpoint was change from baseline in urine osmolyte concentration. Secondary endpoints included changes in copeptin levels and solute free water clearance. Thirty-three randomized, sodium-glucose cotransporter 2 inhibitor–naïve participants completed the study, 29 of whom (placebo: n = 14; dapagliflozin: n = 15) provided accurate 24-hour urine collections (mean age 59 ± 14 years; left ventricular ejection fraction 31% ± 9%). Dapagliflozin treatment led to an isolated increase in urine glucose excretion by 3.3 mmol/kg/d (95% CI: 2.51–4.04; P < 0.0001) within 48 hours (early) which persisted after 4 weeks (late; 2.7 mmol/kg/d [95% CI: 1.98–3.51]; P < 0.0001). Dapagliflozin treatment increased serum copeptin early (5.5 pmol/L [95% CI: 0.45-10.5]; P < 0.05) and late (7.8 pmol/L [95% CI: 2.77–12.81]; P < 0.01), leading to proportional reductions in free water clearance (early: −9.1 mL/kg/d [95% CI: −14 to −4.12; P < 0.001]; late: −11.0 mL/kg/d [95% CI: −15.94 to −6.07; P < 0.0001]) and elevated urine concentrations (late: 134 mmol/L [95% CI: 39.28–229.12]; P < 0.01). Therefore, urine volume did not significantly increase with dapagliflozin (mean difference early: 2.8 mL/kg/d [95% CI: −1.97 to 7.48; P = 0.25]; mean difference late: 0.9 mL/kg/d [95% CI: −3.83 to 5.62]; P = 0.70). Physiological-adaptive water conservation eliminated the expected osmotic diuretic potential of dapagliflozin and thereby prevented a glucose-driven increase in urine volume of approximately 10 mL/kg/d · 75 kg = 750 mL/kg/d. (Hepato-renal Regulation of Water Conservation in Heart Failure Patients With SGLT-2 Inhibitor Treatment [DAPA-Shuttle1]; NCT04080518). [Display omitted] [ABSTRACT FROM AUTHOR]

Dormancy represents a fascinating adaptive strategy for organisms to survive in unforgiving environments. After a period of dormancy, organisms often exhibit exceptional resilience. This period is typically divided into hibernation and aestivation based on seasonal patterns. However, the mechanisms by which organisms adapt to their environments during dormancy, as well as the potential relationships between different states of dormancy, deserve further exploration. Here, we selected Perccottus glenii and Protopterus annectens as the primary subjects to study hibernation and aestivation, respectively. Based on histological and transcriptomic analysis of multiple organs, we discovered that dormancy involved a coordinated functional response across organs. Enrichment analyses revealed noteworthy disparities between the two dormant species in their responses to extreme temperatures. Notably, similarities in gene expression patterns pertaining to energy metabolism, neural activity, and biosynthesis were noted during hibernation, suggesting a potential correlation between hibernation and aestivation. To further explore the relationship between these two phenomena, we analyzed other dormancy-capable species using data from publicly available databases. This comparative analysis revealed that most orthologous genes involved in metabolism, cell proliferation, and neural function exhibited consistent expression patterns during dormancy, indicating that the observed similarity between hibernation and aestivation may be attributable to convergent evolution. In conclusion, this study enhances our comprehension of the dormancy phenomenon and offers new insights into the molecular mechanisms underpinning vertebrate dormancy. [ABSTRACT FROM AUTHOR]

Abstract Aestivation and hibernation represent distinct forms of animal quiescence, characterized by physiological changes, including ion composition. Intracellular ion flows play a pivotal role in eliciting alterations in membrane potential and facilitating cellular communication, while outward K+ currents aid in the restitution and upkeep of the resting membrane potential. This study explores the relationship between inward and outward currents during aestivation in Achatina fulica snails. Specimens were collected near MSUBIT University in Shenzhen and divided into two groups. The first group was kept on a lattice diet, while the second one consisted of aestivating individuals, that were deprived of food and water until a cork-like structure sealed their shells. Recording of current from isolated neurons were conducted using the single-electrode voltage clamp mode with an AxoPatch 200B amplifier. Electrophysiological recordings on pedal ganglia neurons revealed significant differences in the inactivation processes of the Ia and Ikdr components. Alterations in the Ikdr component may inhibit pacemaker activity in pedal ganglion neurons, potentially contributing to locomotion cessation in aestivated animals. The KS current remains unaffected during aestivation. Changes in slow K+ current components could disrupt the resting membrane potential, possibly leading to cell depolarization and influx of Ca2+ and Na+ ions, impacting cell homeostasis. Thus, maintaining the constancy of outward K+ current is essential for cell stability.

Different populations of hosts and parasites experience distinct seasonality in environmental factors, depending on local-scale biotic and abiotic factors. This can lead to highly heterogeneous disease outcomes across host ranges. Variable seasonality characterizes urogenital schistosomiasis, a neglected tropical disease caused by parasitic trematodes (Schistosoma haematobium). Their intermediate hosts are aquatic Bulinus snails that are highly adapted to extreme rainfall seasonality, undergoing prolonged dormancy yearly. While Bulinus snails have a remarkable capacity for rebounding following dormancy, we investigated the extent to which parasite survival within snails is diminished. We conducted an investigation of seasonal snail schistosome dynamics in 109 ponds of variable ephemerality in Tanzania from August 2021 to July 2022. First, we found that ponds have two synchronized peaks of schistosome infection prevalence and observed cercariae, though of lower magnitude in the fully desiccating than non-desiccating ponds. Second, we evaluated total yearly schistosome prevalence across an ephemerality gradient, finding ponds with intermediate ephemerality to have the highest infection rates. We also investigated dynamics of non-schistosome trematodes, which lacked synonymity with schistosome patterns. We found peak schistosome transmission risk at intermediate pond ephemerality, thus the impacts of anticipated increases in landscape desiccation could result in increases or decreases in transmission risk with global change. [ABSTRACT FROM AUTHOR]

Bulinus snails surviving drought play a key role in the seasonal transmission of urogenital schistosomiasis, although our knowledge of their adaptation to dry season is still limited. We investigated the survival dynamic and infestation by the Schistosoma haematobium of Bulinus snails during the dry and rainy seasons in a single pond in an area of seasonal schistosomiasis transmission in Senegal. During the rainy season, 98 (94.23%) B. senegalensis and six (5.76%) B. umbilicatus were collected, respectively. In the dry season, B. umbilicatus outnumbered B. senegalensis, but all five (100%) B. senegalensis collected were viable and alive after the interruption of aestivation by immersion in water, while only 7 of 24 (29.16%) B. umbilicatus collected emerged from their dormant state. The rate of infestation with S. haeamatobium during the rainy season was 18.2% (19/104), while all the viable snails collected during the dry season were negative. B. senegalensis and B. umbilicatus have different seasonal dynamics with no evidence of maintaining S. haematobium infestation during the drought. Further studies including more survey sites and taking account both snails biology and ecological conditions are needed to better understand snail adaptation to seasonal changes and their ability to maintain S. haeamatobium infestation during drought.

The Indian apple snail Pila globosa (Swainson) experiences an annual cycle of aestivation (summer sleep) as a survival strategy during a hot and dry period to avoid damage from high temperatures and the risk of desiccation. Alterations in the external environment reflect in their haemolymph. Changes in enzyme levels because of any type of stress are immediately reflected in the functional responses of animals. These environmental factors can be simulated in the laboratory so as to study enzymatic alterations occurring in the haemolymph of snails to overcome the adverse features during aestivation. Phosphatase enzymes are important for many biological functions. Acid and alkaline phosphatase activities have been studied in the haemolymph of three months aestivated and active snails. The activity level of enzymes ACP decreased and ALP increased significantly in the haemolymph of aestivated P. globosa when compared to active snails. The significance of these findings is discussed. This investigation explains the adaptability of P. globosa to overcome the adverse features during aestivation. This study also reveals that Pila globosa is a suitable model for studies on aestivation and provides an interesting case of aestivation.

Aestivation is considered to be one of the "purest" hypometabolic states in nature, as it involves aerobic dormancy that can be induced and sustained without complex factors. Animals that undergo aestivation to protect themselves from environmental stressors such as high temperatures, droughts, and food shortages. However, this shift in body metabolism presents new challenges for survival, including oxidative stress upon awakening from aestivation, accumulation of toxic metabolites, changes in energy sources, adjustments to immune status, muscle atrophy due to prolonged immobility, and degeneration of internal organs due to prolonged food deprivation. In this review, we summarize the physiological and metabolic strategies, key regulatory factors, and networks utilized by aestivating animals to address the aforementioned components of aestivation. Furthermore, we present a comprehensive overview of the advancements made in aestivation research across major species, including amphibians, fish, reptiles, annelids, mollusks, and echinoderms, categorized according to their respective evolutionary positions. This approach offers a distinct perspective for comparative analysis, facilitating an understanding of the shared traits and unique features of aestivation across different groups of organisms. [ABSTRACT FROM AUTHOR]

Migration plays an important role in the life cycle of many insect species, allowing them to escape unfavourable seasonal conditions. The Bogong moth (Agrotis infusa) is a keystone species that undertakes a long-distance annual migration, with billions of individuals aestivating in summer in the Australian Alps. This species has undergone drastic population declines in the past five years, with steady long-term declines also recorded since the 1980s, and has recently been recognised as Endangered by the IUCN. Despite the role of Bogong moths as a keystone species in the Australian sub-alpine and alpine zones, their feeding habits during their time in the mountains remain understudied, although earlier research suggested that they do not feed during their summer aestivation. To examine whether Bogong moths visit flowers during the summer, we collected pollen from moths caught at a high elevation site in the Australia Alps over the 2021/22 summer period and then identified and counted pollen using light microscopy. We show for the first time that Bogong moths visit a broad range of plant species during their summer activity period and characterise the plant assemblage visited. Almost all the 129 moths sampled carried pollen in large quantities, with a mean of 521 grains per moth. Individual moths varied considerably in pollen load and species composition, suggesting generalist flower visitation. The pollen taxa present on moths indicates local flower feeding at high elevation sites, rather than pollen carried from the lowland origins of migrants. The presence of pollen throughout summer indicates continual flower feeding activity. These results provide important new insights into the ecology of Bogong moths and suggest they could play a previously unrecognised role in pollination in sub-alpine and alpine ecosystems.

Environmental perturbations evoke down-regulation of metabolism in some multicellular organisms, leading to dormancy, or torpor. Colonies of the urochordate Botrylloides leachii enter torpor in response to changes in seawater temperature and may survive for months as small vasculature remnants that lack feeding and reproductive organs but possess torpor-specific microbiota. Upon returning to milder conditions, the colonies rapidly restore their original morphology, cytology and functionality while harboring re-occurring microbiota, a phenomenon that has not been described in detail to date. Here we investigated the stability of B. leachii microbiome and its functionality in active and dormant colonies, using microscopy, qPCR, in situ hybridization, genomics and transcriptomics. A novel lineage of Endozoicomonas, proposed here as Candidatus Endozoicomonas endoleachii, was dominant in torpor animals (53-79% read abundance), and potentially occupied specific hemocytes found only in torpid animals. Functional analysis of the metagenome-assembled genome and genome-targeted transcriptomics revealed that Endozoicomonas can use various cellular substrates, like amino acids and sugars, potentially producing biotin and thiamine, but also expressing various features involved in autocatalytic symbiosis. Our study suggests that the microbiome can be linked to the metabolic and physiological states of the host, B. leachii, introducing a model organism for the study of symbioses during drastic physiological changes, such as torpor. [ABSTRACT FROM AUTHOR]

Abstract Background We have previously shown that iatrogenic dehydration is associated with a shift to organic osmolyte production in the general ICU population. The aim of the present investigation was to determine the validity of the physiological response to dehydration known as aestivation and its relevance for long-term disease outcome in COVID-19. Methods The study includes 374 COVID-19 patients from the Pronmed cohort admitted to the ICU at Uppsala University Hospital. Dehydration data was available for 165 of these patients and used for the primary analysis. Validation was performed in Biobanque Québécoise de la COVID-19 (BQC19) using 1052 patients with dehydration data. Dehydration was assessed through estimated osmolality (eOSM = 2Na + 2 K + glucose + urea), and correlated to important endpoints including death, invasive mechanical ventilation, acute kidney injury, and long COVID-19 symptom score grouped by physical or mental. Results Increasing eOSM was correlated with increasing role of organic osmolytes for eOSM, while the proportion of sodium and potassium of eOSM were inversely correlated to eOSM. Acute outcomes were associated with pronounced dehydration, and physical long-COVID was more strongly associated with dehydration than mental long-COVID after adjustment for age, sex, and disease severity. Metabolomic analysis showed enrichment of amino acids among metabolites that showed an aestivating pattern. Conclusions Dehydration during acute COVID-19 infection causes an aestivation response that is associated with protein degradation and physical long-COVID. Trial registration: The study was registered à priori (clinicaltrials.gov: NCT04316884 registered on 2020-03-13 and NCT04474249 registered on 2020-06-29). Graphical abstract

The Indian apple snail Pila globosa (Swainson) experiences an annual cycle of aestivation (summer sleep) as a survival strategy during a hot and dry period to avoid damage from high temperatures and the risk of desiccation. Alterations in the external environment reflect in their haemolymph. Changes in enzyme levels because of any type of stress are immediately reflected in the functional responses of animals. These environmental factors can be simulated in the laboratory so as to study enzymatic alterations occurring in the haemolymph of snails to overcome the adverse features during aestivation. Phosphatase enzymes are important for many biological functions. Acid and alkaline phosphatase activities have been studied in the haemolymph of three months aestivated and active snails. The activity level of enzymes ACP decreased and ALP increased significantly in the haemolymph of aestivated P. globosa when compared to active snails. The significance of these findings is discussed. This investigation explains the adaptability of P. globosa to overcome the adverse features during aestivation. This study also reveals that Pila globosa is a suitable model for studies on aestivation and provides an interesting case of aestivation. [ABSTRACT FROM AUTHOR]

This study was performed to investigate the effects of selenium yeast (Se-yeast) on the growth, intestinal health, immune status and body composition of juvenile Apostichopus japonicus before and after aestivation. Five experimental diets were formulated with increasing addition of Se-yeast (0, 0.5, 1.0, 1.5 and 2.0 mg/kg), with the diet without Se-yeast as the control. Each diet was randomly assigned to three tanks of juvenile A. japonicus (initial body weight: 2.96 ± 0.04 g). The whole experiment lasted for 135 days, which included a 45-day feeding experiment before aestivation, a 60-day aestivation phage and a 30-day feeding experiment after aestivation. The results showed that weight gain rate (WGR) was significantly increased by the increasing addition of Se-yeast before aestivation. After aestivation, WGR was markedly elevated by 1.0 mg/kg Se-yeast but was inhibited by 1.5–2.0 mg/kg Se-yeast. The evisceration rate (ER) of A. japonicus was obviously inhibited by the relatively higher addition level of Se-yeast (1.5–2.0 mg/kg) before aestivation. After aestivation, the ER was significantly inhibited by Se-yeast at an addition of 1.5 mg/kg. Before aestivation, the highest activities of all digestive enzymes were obtained by Se-yeast addition at a level equal to or above 1.0 mg/kg Se-yeast. After aestivation, the activities of most digestive enzymes were maximized by Se-yeast at the addition level of no more than 1.0 mg/kg. Before aestivation, the activities of nitric oxide synthase and alkaline phosphatase significantly increased by the increasing addition of Se-yeast. After aestivation, immune related parameters exhibited the highest or comparable values when the addition level of Se-yeast was equal to or less than 1.0 mg/kg. Notably, the selenium content in the body wall of A. japonicus increased significantly as Se-yeast addition increased in the diets. These results showed that Se-yeast at the addition level of 1.5–2.0 mg/kg before aestivation and 1.0–1.5 mg/kg after aestivation was beneficial for the promotion of growth, intestinal health and immune status of juvenile A. japonicus. [ABSTRACT FROM AUTHOR]

The constant increase in temperatures under global warming has led to a prolonged aestivation period for Apostichopus japonicus, resulting in considerable losses in production and economic benefits. However, the specific mechanism of aestivation has not been fully elucidated. In this study, we first tried to illustrate the biological mechanisms of aestivation from the perspective of the gut microbiota and metabolites. Significant differences were found in the gut microbiota of aestivating adult A. japonicus (AAJSD group) compared with nonaestivating adult A. japonicus (AAJRT group) and young A. japonicus (YAJRT and YAJSD groups) based on 16S rRNA gene high-throughput sequencing analysis. The abundances of Desulfobacterota, Myxococcota, Bdellovibrionota, and Firmicutes (4 phyla) in the AAJSD group significantly increased. Moreover, the levels of Pseudoalteromonas, Fusibacter, Labilibacter, Litorilituus, Flammeovirga, Polaribacter, Ferrimonas, PB19, and Blfdi19 genera were significantly higher in the AAJSD group than in the other three groups. Further analysis of the LDA effect size showed that species with significant variation in abundance in the AAJSD group, including the phylum Firmicutes and the genera Litorilituus, Fusibacter, and Abilibacter, might be important biomarkers for aestivating adult A. japonicus. In addition, the results of metabolomics analysis showed that there were three distinct metabolic pathways, namely biosynthesis of secondary metabolites, tryptophan metabolism, and sesquiterpenoid and triterpenoid biosynthesis in the AAJSD group compared with the other three groups. Notably, 5-hydroxytryptophan was significantly upregulated in the AAJSD group in the tryptophan metabolism pathway. Moreover, the genera Labilibacter, Litorilituus, Ferrimonas, Flammeovirga, Blfdi19, Fusibacter, Pseudoalteromonas, and PB19 with high abundance in the gut of aestivating adult A. japonicus were positively correlated with the metabolite 5-HTP. These findings suggest that there may be potential biological associations among the gut microbiota, metabolites, and aestivation in A. japonicus. This work may provide a new perspective for further understanding the aestivation mechanism of A. japonicus. [ABSTRACT FROM AUTHOR]

Environmental perturbations evoke down-regulation of metabolism in some multicellular organisms, leading to dormancy, or torpor. Colonies of the urochordate Botrylloides leachii enter torpor in response to changes in seawater temperature and may survive for months as small vasculature remnants that lack feeding and reproductive organs but possess torpor-specific microbiota. Upon returning to milder conditions, the colonies rapidly restore their original morphology, cytology and functionality while harboring re-occurring microbiota, a phenomenon that has not been described in detail to date. Here we investigated the stability of B. leachii microbiome and its functionality in active and dormant colonies, using microscopy, qPCR, in situ hybridization, genomics and transcriptomics. A novel lineage of Endozoicomonas, proposed here as Candidatus Endozoicomonas endoleachii, was dominant in torpor animals (53–79% read abundance), and potentially occupied specific hemocytes found only in torpid animals. Functional analysis of the metagenome-assembled genome and genome-targeted transcriptomics revealed that Endozoicomonas can use various cellular substrates, like amino acids and sugars, potentially producing biotin and thiamine, but also expressing various features involved in autocatalytic symbiosis. Our study suggests that the microbiome can be linked to the metabolic and physiological states of the host, B. leachii, introducing a model organism for the study of symbioses during drastic physiological changes, such as torpor.

Aestivation is a special ability possessed by some animals to cope with hot and dry environments utilizing dormancy. At a macroscopic level, dormant animals stop moving and eating. At the microscopic level, the expression of a large number of genes in these animals is strictly controlled. However, little is known about what changes occur during aestivation, especially in fish. In this study, we used transcriptome analysis to examine what changes occur in the gills and lungs of the African lungfish (Protopterus annectens) during the maintenance phase of aestivation and speculated on their causes. We found that aestivating transcriptomes were highly similar between gills and lungs. We also found that some genes showed differential expression or alternative splicing, which may be associated with different organs. In addition, differential expression analysis revealed that the lungs maintained significantly higher bioactivity during aestivation, which suggests that the main respiratory organ in aestivating lungfish can transform. Our study provides a reference point for studying the relationship between aestivation and hibernation and further increases understanding of aestivation. [ABSTRACT FROM AUTHOR]

Understanding the factors that determine the spatial distribution of species is crucial for conservation planning. In this short communication, we review previous distribution models of the fire salamander (Salamandra infraimmaculata) in northern Israel, produced by the group of the late Prof. Leon Blaustein, while suggesting a biologically-informed reinterpretation of their main predictions. We argue for the prime importance of bedrock, specifically hard limestone, because it is tightly associated with the availability of karstic formations that are key to adult survival throughout the summer. Furthermore, we suggest that the spatial distribution of limestone bedrock also determines large-scale inter-population connectivity, and may explain the observed genetic differentiation among populations, as well as the southernmost limit of the species' global distribution. [ABSTRACT FROM AUTHOR]

The reproductive lifespans of turtles are consistently long, but reproductive cycles are under environmental control and thus can vary within species, populations, and individuals over time and space. Knowledge of turtle species' reproductive traits and their associated variances over time and space are critical to understanding the dynamics of turtle populations, especially those requiring management or conservation. Deirochelys reticularia is a species being considered for protection by the US Fish and Wildlife Service and contains 3 subspecies with some differences in reproductive characteristics of nesting season, annual nesting frequency, and egg retention. We collected ultrasound and x-radiograph data in Texas to identify the maturation size, nesting season, annual nesting frequency, and clutch size of female D. r. miaria in Texas. We observed no reproductive activity in individuals from 101 to 146 mm in plastron length (PL) and detected either unshelled eggs, shelled eggs, or both in individuals from 150 to 197 mm PL. Maturation sizes were similar to those in other regions and for other subspecies. We observed shelled clutches or nesting events from April to July, confirming a spring–summer nesting season in Texas consistent with other D. r. miaria sites and supporting the paradigm that the western subspecies does not follow the autumn–winter nesting season of the other subspecies. We found no evidence that individuals retain shelled eggs while aestivating or overwintering. Individuals nested up to 3 times/yr in Texas. Individuals laid 7–11 eggs and the mean clutch size was 9.2 eggs, similar to other regions and other subspecies. Nesting phenology is regionally variable, so management plans and policies for the species will need to consider that variation and potentially recognize management differences among D. reticularia subspecies. [ABSTRACT FROM AUTHOR]

The persistence of parasite populations through harsh seasonal bouts is often critical to circannual disease outbreaks. Parasites have a diverse repertoire of phenotypes for persistence, ranging from transitioning to a different life stage better suited to within-host dormancy to utilizing weather-hardy structures external to hosts. While these adaptive traits allow parasite species to survive through harsh seasons, it is often at survival rates that threaten population persistence. We argue that these periods of parasite (and vector) population busts could be ideal targets for disease intervention. As climate change portends abbreviated host dormancy and extended transmission periods in many host–parasite systems, it is essential to identify novel pathways to shore up current disease-intervention strategies. Hosts and vectors have impressive capabilities for seasonal dormancy, with many species remaining inactive for more than half of the annual cycle. Global change has impacted the duration of these climate-adaptive behaviors, with the potential for temporal, spatial, or thermal mismatches between host and parasite. Alterations in the duration of host/vector dormancy could increase or decrease the number of favorable days for parasites, with profound impacts on disease outcomes. Disease interventions are strengthened by incorporating knowledge of the phenology of vectors and intermediate hosts. [ABSTRACT FROM AUTHOR]

Aestivation is considered to be one of the “purest” hypometabolic states in nature, as it involves aerobic dormancy that can be induced and sustained without complex factors. Animals that undergo aestivation to protect themselves from environmental stressors such as high temperatures, droughts, and food shortages. However, this shift in body metabolism presents new challenges for survival, including oxidative stress upon awakening from aestivation, accumulation of toxic metabolites, changes in energy sources, adjustments to immune status, muscle atrophy due to prolonged immobility, and degeneration of internal organs due to prolonged food deprivation. In this review, we summarize the physiological and metabolic strategies, key regulatory factors, and networks utilized by aestivating animals to address the aforementioned components of aestivation. Furthermore, we present a comprehensive overview of the advancements made in aestivation research across major species, including amphibians, fish, reptiles, annelids, mollusks, and echinoderms, categorized according to their respective evolutionary positions. This approach offers a distinct perspective for comparative analysis, facilitating an understanding of the shared traits and unique features of aestivation across different groups of organisms.

Background: We have previously shown that iatrogenic dehydration is associated with a shift to organic osmolyte production in the general ICU population. The aim of the present investigation was to determine the validity of the physiological response to dehydration known as aestivation and its relevance for long-term disease outcome in COVID-19.Methods: The study includes 374 COVID-19 patients from the Pronmed cohort admitted to the ICU at Uppsala University Hospital. Dehydration data was available for 165 of these patients and used for the primary analysis. Validation was performed in Biobanque Québécoise de la COVID-19 (BQC19) using 1052 patients with dehydration data. Dehydration was assessed through estimated osmolality (eOSM = 2Na + 2 K + glucose + urea), and correlated to important endpoints including death, invasive mechanical ventilation, acute kidney injury, and long COVID-19 symptom score grouped by physical or mental.Results: Increasing eOSM was correlated with increasing role of organic osmolytes for eOSM, while the proportion of sodium and potassium of eOSM were inversely correlated to eOSM. Acute outcomes were associated with pronounced dehydration, and physical long-COVID was more strongly associated with dehydration than mental long-COVID after adjustment for age, sex, and disease severity. Metabolomic analysis showed enrichment of amino acids among metabolites that showed an aestivating pattern.Conclusions: Dehydration during acute COVID-19 infection causes an aestivation response that is associated with protein degradation and physical long-COVID.Trial Registration: The study was registered à priori (clinicaltrials.gov: NCT04316884 registered on 2020-03-13 and NCT04474249 registered on 2020-06-29). [ABSTRACT FROM AUTHOR]

Understanding the factors that determine the spatial distribution of species is crucial for conservation planning. In this short communication, we review previous distribution models of the fire salamander (Salamandra infraimmaculata) in northern Israel, produced by the group of the late Prof. Leon Blaustein, while suggesting a biologically-informed reinterpretation of their main predictions. We argue for the prime importance of bedrock, specifically hard limestone, because it is tightly associated with the availability of karstic formations that are key to adult survival throughout the summer. Furthermore, we suggest that the spatial distribution of limestone bedrock also determines large-scale inter-population connectivity, and may explain the observed genetic differentiation among populations, as well as the southernmost limit of the species' global distribution. [ABSTRACT FROM AUTHOR]

DNAJ proteins function as co-chaperones of HSP70 and play key roles in cell physiology to promote protein folding and degradation, especially under environmental stress. Based on our previous study on HSP70, a systematic study of DNAJ was performed in sea cucumber Apostichopus japonicus using the transcriptomic and genomic data, identifying 43 AjDNAJ genes, including six AjDNAJA genes, eight AjDNAJB genes, and 29 AjDNAJC genes. Slight expansion and conserved genomic structure were observed using the phylogenetic and syntenic analysis. Differential period-specific and tissue-specific expression patterns of AjDNAJs were observed between adult and juvenile individuals during aestivation. Strong tissue-specific expression correlations between AjDNAJ and AjHSP70 genes were found, indicating that the involvements of AjHSP70IVAs in the aestivation of sea cucumbers were regulated by AjDNAJs. Several key genes with significant expression correlations, such as AjDNAJB4L and AjHSP70IVAs, were suggested to function together under heat stress. Together, these findings provide early insight into the involvement of AjDNAJs in the aestivation and their roles as co-chaperones of AjHSP70s. [ABSTRACT FROM AUTHOR]

In response to seasonal droughts, the green striped burrowing frog Cyclorana alboguttata enters a reversible hypometabolic state called aestivation where heart rate and oxygen consumption can be reduced despite warm (>25C°) ambient temperatures. With a view to understanding molecular mechanisms we profiled aestivating versus control gastrocnemius muscle using mRNA sequencing. This indicated an extensive metabolic reprogramming, with nearly a quarter of the entire transcriptome (3996 of 16,960 mRNA) exhibiting a nominal >2-fold change. Consistent with a physiological adaptation to spare carbohydrate reserves, carbohydrate catabolism was systemically downregulated. A 630-fold downregulation of ENO3 encoding the enolase enzyme was most striking. The 590 frog orthologs of mRNA encoding the mitoproteome were, viewed as a population, significantly downregulated during aestivation, although not to the same extent as mRNA encoding carbohydrate catabolism. Prominent examples include members of the TCA cycle (IDH2), electron transport chain (NDUFA6), the ATP synthase complex (ATP5F1B) and ADP/ATP intracellular transport (SLC25A4). Moreover, mRNA derived from the mt genome itself (e.g. mt-ND1) were also downregulated. Most prominent among the upregulated mRNA are those encoding aspects of regulated proteolysis including the proteosome (e.g. PSME4L), peptidases (USP25), atrogins (FBXO32) and ubiquitination (VCP). Finally, we note the ∼5-fold upregulation of the mRNA EIFG3 that encodes part of the EIF4F complex. This possesses global control of protein synthesis. Given protein synthesis is repressed in aestivating frogs this indicates the skeletal musculature is poised for accelerated translation of mRNA upon emergence, supporting a strategy to rapidly restore function when the summer rains come. [Display omitted] • We have explored global gene expression in the muscle of dormant desert frogs. • The extent of mRNA reprogramming is dramatic. • Key metabolic pathways include glycolysis and mitochondrial function. • The strongest points of regulation do not always correspond to the rate limiters. [ABSTRACT FROM AUTHOR]

To explore the impacts of sea cucumber aestivation on sediment composition, sediments were sampled from aestivation sites and non-aestivation sites of a commercial Apostichopus japonicus culture pond, and metabolome–metagenome integrated analysis was performed. The results showed that 1) there was no significant difference in the microbial composition of sediments between aestivation and non-aestivation sites, but the relative abundances of some bacterial species changed slightly (especially pathogenic and spoilage species); 2) altered average relative abundances of potential host bacteria of antibiotic resistance genes (ARGs) were observed; 3) compared with non-aestivation site sediments, decreased average absolute abundances of two ARGs (tetW and floR) and increased average absolute abundance of one ARG (tetM) were observed in aestivation site sediments; and 4) a total of 74 significantly differentially expressed metabolites (SDMs) were identified in aestivation sites compared with non-aestivation sites. Four SDMs were closely correlated with antibacterial activity and bacterial physiology. All data observed in this study indicate that sea cucumber aestivation does not affect sediment microbial composition but does influence the relative abundances of some bacteria species; in addition, tetM might be considered a key indicator for monitoring and indicating ARG transfer or the sediment status of sea cucumber culture ponds during aestivation. In conclusion, the observations of this study enrich our knowledge of the impacts of the physiological behavior of marine ecosystem inhabitants on their ecosystem and provide novel insights for the management of aquaculture activities. [Display omitted] • Marine sediments were sampled from aestivation and non-aestivation sites of a sea cucumber aquaculture pond. • Comparative metagenomic and metabolomic analyses were performed. • Sea cucumber aestivation alters the relative abundance of some species but not the sediment microbiome composition. • Aestivated sea cucumbers increase the relative contents of antibacterial-related metabolites to self-protection. • tetM could be a key indicator for monitoring the sediment status of sea cucumber culture ponds during aestivation. [ABSTRACT FROM AUTHOR]

The constant increase in temperatures under global warming has led to a prolonged aestivation period for Apostichopus japonicus, resulting in considerable losses in production and economic benefits. However, the specific mechanism of aestivation has not been fully elucidated. In this study, we first tried to illustrate the biological mechanisms of aestivation from the perspective of the gut microbiota and metabolites. Significant differences were found in the gut microbiota of aestivating adult A. japonicus (AAJSD group) compared with nonaestivating adult A. japonicus (AAJRT group) and young A. japonicus (YAJRT and YAJSD groups) based on 16S rRNA gene high-throughput sequencing analysis. The abundances of Desulfobacterota, Myxococcota, Bdellovibrionota, and Firmicutes (4 phyla) in the AAJSD group significantly increased. Moreover, the levels of Pseudoalteromonas, Fusibacter, Labilibacter, Litorilituus, Flammeovirga, Polaribacter, Ferrimonas, PB19, and Blfdi19 genera were significantly higher in the AAJSD group than in the other three groups. Further analysis of the LDA effect size showed that species with significant variation in abundance in the AAJSD group, including the phylum Firmicutes and the genera Litorilituus, Fusibacter, and Abilibacter, might be important biomarkers for aestivating adult A. japonicus. In addition, the results of metabolomics analysis showed that there were three distinct metabolic pathways, namely biosynthesis of secondary metabolites, tryptophan metabolism, and sesquiterpenoid and triterpenoid biosynthesis in the AAJSD group compared with the other three groups. Notably, 5-hydroxytryptophan was significantly upregulated in the AAJSD group in the tryptophan metabolism pathway. Moreover, the genera Labilibacter, Litorilituus, Ferrimonas, Flammeovirga, Blfdi19, Fusibacter, Pseudoalteromonas, and PB19 with high abundance in the gut of aestivating adult A. japonicus were positively correlated with the metabolite 5-HTP. These findings suggest that there may be potential biological associations among the gut microbiota, metabolites, and aestivation in A. japonicus. This work may provide a new perspective for further understanding the aestivation mechanism of A. japonicus.

Bulinus globosus snails inhabiting ephemeral rivers and ponds in sub-Saharan Africa experience seasonal water-level fluctuations and habitat desiccation. These environmental changes can instigate the aestivation of snails as a survival strategy. However, the net effect of these changes on snail population size following a period of desiccation and resuscitation is poorly understood. To lessen this knowledge gap, we evaluated the effects of desiccation on the fecundity and longevity of Bulinus globosus snails under laboratory conditions. The periods of desiccation used were 57, 64, 71 and 78 days. Our results showed that an increase in desiccation time from 57 to 78 days was associated with a twofold reduction in fecundity. Furthermore, the survival time of B. globosus snails decreased linearly with desiccation time. The median survival time of snails exposed to desiccation for 57 and 78 days was 63 days and 35 days, respectively. Reduction in the fecundity and snail survival post-desiccation may lead to population shrinkage of B. globosus. [ABSTRACT FROM AUTHOR]

Polyploid breeding is widely used in aquaculture as an important area of new research. We have previously grown Apostichopus japonicus triploids with a growth advantage. The body length, body weight, and aestivation time of triploid and diploid A. japonicus were measured in this study, and the transcriptome and metabolome were used to examine the growth advantage of triploids A. japonicus. The results showed that the proportion of triploid A. japonicus with a body length of 6–12 cm and 12–18 cm was significantly higher than that of diploid A. japonicus, and triploid A. japonicus had a shorter aestivation time (39 days) than diploid (63 days). We discovered 3296 differentially expressed genes (DEGs); 13 DEGs (for example, cyclin-dependent kinase 2) related to growth advantage, immune regulation, and energy storage were screened as potential candidates. According to Gene Ontology (GO) enrichment analysis, DEGs were significantly enriched in the cytoplasm (cellular component), ATP binding process (molecular function), oxidation–reduction process (biological process), and other pathways. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment data, DEGs were significantly enriched in ribosome production and other areas. We discovered 414 significant differential metabolites (SDMs), with 11 important SDMs (for example, nocodazole) linked to a growth advantage. SDMs are significantly enriched in metabolic pathways, as well as other pathways, according to the KEGG enrichment results. According to a combined transcriptome and metabolome analysis, 6 DEGs have regulatory relationships with 11 SDMs, which act on 11 metabolic pathways together. Our results further enrich the biological data of triploid A. japonicus and provide useful resources for genetic improvement of this species. [ABSTRACT FROM AUTHOR]

How malaria mosquitoes persist during the dry season in the Sahel and rapidly rebound at the onset of rains is unclear. Recently, Faiman and colleagues demonstrated that aestivation, a summer dormancy mechanism, is a major persistence strategy of Anopheles mosquitoes, which could be targeted by vector control. [ABSTRACT FROM AUTHOR]

Marine invertebrates are facing increasing pressure from climate change, such as increasing temperature. Sea cucumber (Apostichopus japonicus) is an ectotherm and marine model organism for the study of aestivation, a state of dormancy caused by high temperature. The adaptive mechanism of successive temperature stress and aestivation remains unclear in A. japonicus. This study experimentally exposed A. japonicus to constant temperature (14 ℃) in 20 days, successive increasing temperature (14–20 and 14–26 ℃) in 15 days and then constant aestivation temperature (20 ℃ and 26 ℃) in 5 days, aiming to explore how biogenic amines and signal transduction pathways regulated energy metabolism to response to temperature increasing and aestivation in the A. japonicus. Together with correlation analysis, this experiment suggested that (1) when temperature increased, serotonin might react first to down-regulate cyclic AMP and protein kinase A signal transduction pathway through the receptor 5-HT1A, which led to the suppression of key metabolic enzymes; (2) during aestivation, calmodulin (CaM) and AMP-activated protein kinase (AMPK) increased, and then up-regulated the catabolism of carbohydrates and proteins to provide energy for aestivation. The sea cucumber on aestivation under the higher temperature stress (26 ℃) showed the higher contents of CaM and AMPK, and similar trends were found in glycogen phosphorylase and pyruvate kinase activities, meaning a higher energy catabolism; this implied that under the scenario of successive heatwaves happened in ocean, the aestivation mechanism itself might not be able to guarantee the sea cucumber's survival in the future. [ABSTRACT FROM AUTHOR]

1. Climate change has forced species to shift distribution, alter migration behaviour, or change phenology. One of these adaptation strategies is aestivation to overcome hot, dry summers. For example, the abundance of the Great Banded Grayling Brintesia circe Fabricius (Lepidoptera, Nymphalidae) in Southern Germany used to show one flight peak between June and August, while now, a bimodal phenological record suggests 3–4 weeks of aestivation during the driest summer weeks. 2. To study this new phenomenon, a capture‐mark‐recapture study was performed in two nature reserves in Southern Germany during 92 days in 2019 and 2020. Gender, wing condition, and exact location of individuals of B. circe were recorded. These data show that in June (first flight period), 76%, 481 of 635 captured individuals were males, while in late August and September (second flight period), ≥95%, 452 of 462 were females. No individual marked during the first flight period was recaptured during the second flight period. 3. The results imply that mating takes place during the first flight period only, especially females aestivate, probably to avoid oviposition during the hottest and driest parts of the summer and that an unknown part of the population may disperse out or into the investigated habitats. This behaviour appears to have changed during the last decades probably as an adaptation to climate change. Females of B. circe are forced to oviposit later in summer as earlier eggs laid during hotter and drier times are less likely to develop successfully. [ABSTRACT FROM AUTHOR]

Echinoderms are marine deuterostomes with fascinating adaptation features such as aestivation and organ regeneration. However, post-transcriptional gene regulation by microRNAs (miRNAs) underlying these features are largely unexplored. Here, using homology-based and de novo approaches supported by expression data, we provided a comprehensive annotation of miRNA genes in the sea cucumber Apostichopus japonicus. By linkage and phylogenic analyses, we characterized miRNA genomic organization, evolutionary history and expression regulation. The results showed that sea cucumbers evolved a large number of new miRNAs, which tended to form polycistronic clusters via tandem duplication that had been especially active in the echinoderms. Most new miRNAs were weakly expressed, but miRNA clustering increased the expression level of clustered new miRNAs. The most abundantly expressed new miRNAs were organized in a single tandem cluster (cluster n2), which was activated during aestivation and intestine regeneration. Overall, our analyses suggest that clustering of miRNAs is important for their evolutionary origin, expression control, and functional cooperation. • Evolution of sea cucumber miRNAs is a dynamic and active process, which has given rise to numerous new miRNA families. • New miRNAs are enriched in the tube feet or the regenerating intestine and involved in regulation of these specific organs. • The key new miRNAs for regulation of aestivation and regeneration are organized in a single tandem cluster (cluster n2). • miRNA clustering increased the expression level of new miRNAs, which might enhance their functionality. • miRNAs in cluster n2 may collaboratively activate Wnt signaling by suppressing different inhibitors of the Wnt pathway. [ABSTRACT FROM AUTHOR]

Abstract Background How anopheline mosquitoes persist through the long dry season in Africa remains a gap in our understanding of these malaria vectors. To span this period in locations such as the Sahelian zone of Mali, mosquitoes must either migrate to areas of permanent water, recolonize areas as they again become favorable, or survive in harsh conditions including high temperatures, low humidity, and an absence of surface water (required for breeding). Adult mosquitoes surviving through this season must dramatically extend their typical lifespan (averaging 2–3 weeks) to 7 months. Previous work has found evidence that the malaria mosquito An. coluzzii, survives over 200 days in the wild between rainy seasons in a presumed state of aestivation (hibernation), but this state has so far not been replicated in laboratory conditions. The inability to recapitulate aestivation in the lab hinders addressing key questions such as how this state is induced, how it affects malaria vector competence, and its impact on disease transmission. Methods In effort to induce aestivation, we held laboratory mosquitoes in climate-controlled incubators with a range of conditions that adjusted humidity (40–85% RH), temperature (18–27 °C), and light conditions (8–12 h of light) and evaluated their survivorship. These conditions were chosen to mimic the late rainy and dry seasons as well as relevant extremes these mosquitoes may experience during aestivation. Results We found that by priming mosquitoes in conditions simulating the late wet season in Mali, and maintaining mosquitoes in reduced light/temperature, mean mosquito survival increased from 18.34 ± 0.65 to 48.02 ± 2.87 days, median survival increased from 19 (95% CI 17–21) to 50 days (95% CI 40–58), and the maximum longevity increased from 38 to 109 days (P-adj

One of the most exceptional adaptations to extreme drought is found in the sister group to tetrapods, the lungfishes (Dipnoi), which can aestivate inside a mucus cocoon for multiple years at reduced metabolic rates with complete cessation of ingestion and excretion. However, the function of the cocoon tissue is not fully understood. Here we developed a new more natural laboratory protocol for inducing aestivation in the West African lungfish, Protopterus annectens, and investigated the structure and function of the cocoon. We used electron microscopy and imaging of live tissue-stains to confirm that the inner and outer layers of the paper-thin cocoon are composed primarily of living cells. However, we also repeatedly observed extensive bacterial and fungal growth covering the cocoon and found no evidence of anti-microbial activity in vitro against E. coli for the cocoon tissue in this species. This classroom discovery-based research, performed during a course-based undergraduate research experience course (CURE), provides a robust laboratory protocol for investigating aestivation and calls into the question the function of this bizarre vertebrate adaptation., Competing Interests: Conflict of Interest The authors declare no conflict of interest.

Hypertonic dehydration is associated with muscle wasting and synthesis of organic osmolytes. We recently showed a metabolic shift to amino acid production and urea cycle activation in coronavirus-2019 (COVID-19), consistent with the aestivation response. The aim of the present investigation was to validate the metabolic shift and development of long-term physical outcomes in the non-COVID cohort of the Biobanque Québécoise de la COVID-19 (BQC19). We included 824 patients from BQC19, where 571 patients had data of dehydration in the form of estimated osmolality (eOSM = 2Na + 2K + glucose + urea), and 284 patients had metabolome data and long-term follow-up. We correlated the degree of dehydration to mortality, invasive mechanical ventilation, acute kidney injury, and long-term symptoms. As found in the COVID cohort, higher eOSM correlated with a higher proportion of urea and glucose of total eOSM, and an enrichment of amino acids compared with other metabolites. Sex-stratified analysis indicated that women may show a weaker aestivation response. More severe dehydration was associated with mortality, invasive mechanical ventilation, and acute kidney injury during the acute illness. Importantly, more severe dehydration was associated with physical long-term symptoms but not mental long-term symptoms after adjustment for age, sex, and disease severity. Patients with water deficit in the form of increased eOSM tend to have more severe disease and experience more physical symptoms after an acute episode of care. This is associated with amino acid and urea production, indicating dehydration-induced muscle wasting. NEW & NOTEWORTHY We have previously shown that humans exhibit an aestivation-like response where dehydration leads to a metabolic shift to urea synthesis, which is associated with long-term weakness indicating muscle wasting. In the present study, we validate this response in a new cohort and present a deeper metabolomic analysis and pathway analysis. Finally, we present a sex-stratified analysis suggesting weaker aestivation in women. However, women show less dehydration, so the association warrants further study.

Bulinus snails surviving drought play a key role in the seasonal transmission of urogenital schistosomiasis, although our knowledge of their adaptation to dry season is still limited. We investigated the survival dynamic and infestation by the Schistosoma haematobium of Bulinus snails during the dry and rainy seasons in a single pond in an area of seasonal schistosomiasis transmission in Senegal. During the rainy season, 98 (94.23%) B. senegalensis and six (5.76%) B. umbilicatus were collected, respectively. In the dry season, B. umbilicatus outnumbered B. senegalensis , but all five (100%) B. senegalensis collected were viable and alive after the interruption of aestivation by immersion in water, while only 7 of 24 (29.16%) B. umbilicatus collected emerged from their dormant state. The rate of infestation with S. haeamatobium during the rainy season was 18.2% (19/104), while all the viable snails collected during the dry season were negative. B. senegalensis and B. umbilicatus have different seasonal dynamics with no evidence of maintaining S. haematobium infestation during the drought. Further studies including more survey sites and taking account both snails biology and ecological conditions are needed to better understand snail adaptation to seasonal changes and their ability to maintain S. haeamatobium infestation during drought.

Aim: Recent evidence suggests that arterial hypertension could be alternatively explained as a physiological adaptation response to water shortage, termed aestivation, which relies on complex multi‐organ metabolic adjustments to prevent dehydration. Here, we tested the hypothesis that chronic water loss across diseased skin leads to similar adaptive water conservation responses as observed in experimental renal failure or high salt diet. Methods: We studied mice with keratinocyte‐specific overexpression of IL‐17A which develop severe psoriasis‐like skin disease. We measured transepidermal water loss and solute and water excretion in the urine. We quantified glomerular filtration rate (GFR) by intravital microscopy, and energy and nitrogen pathways by metabolomics. We measured skin blood flow and transepidermal water loss (TEWL) in conjunction with renal resistive indices and arterial blood pressure. Results: Psoriatic animals lost large amounts of water across their defective cutaneous epithelial barrier. Metabolic adaptive water conservation included mobilization of nitrogen and energy from muscle to increase organic osmolyte production, solute‐driven maximal anti‐diuresis at normal GFR, increased metanephrine and angiotensin 2 levels, and cutaneous vasoconstriction to limit TEWL. Heat exposure led to cutaneous vasodilation and blood pressure normalization without parallel changes in renal resistive index, albeit at the expense of further increased TEWL. Conclusion: Severe cutaneous water loss predisposes psoriatic mice to lethal dehydration. In response to this dehydration stress, the mice activate aestivation‐like water conservation motifs to maintain their body hydration status. The circulatory water conservation response explains their arterial hypertension. The nitrogen‐dependency of the metabolic water conservation response explains their catabolic muscle wasting. [ABSTRACT FROM AUTHOR]

Aim: We have reported earlier that a high salt intake triggered an aestivation‐like natriuretic‐ureotelic body water conservation response that lowered muscle mass and increased blood pressure. Here, we tested the hypothesis that a similar adaptive water conservation response occurs in experimental chronic renal failure. Methods: In four subsequent experiments in Sprague Dawley rats, we used surgical 5/6 renal mass reduction (5/6 Nx) to induce chronic renal failure. We studied solute and water excretion in 24‐hour metabolic cage experiments, chronic blood pressure by radiotelemetry, chronic metabolic adjustment in liver and skeletal muscle by metabolomics and selected enzyme activity measurements, body Na+, K+ and water by dry ashing, and acute transepidermal water loss in conjunction with skin blood flow and intra‐arterial blood pressure. Results: 5/6 Nx rats were polyuric, because their kidneys could not sufficiently concentrate the urine. Physiological adaptation to this renal water loss included mobilization of nitrogen and energy from muscle for organic osmolyte production, elevated norepinephrine and copeptin levels with reduced skin blood flow, which by means of compensation reduced their transepidermal water loss. This complex physiologic‐metabolic adjustment across multiple organs allowed the rats to stabilize their body water content despite persisting renal water loss, albeit at the expense of hypertension and catabolic mobilization of muscle protein. Conclusion: Physiological adaptation to body water loss, termed aestivation, is an evolutionary conserved survival strategy and an under‐studied research area in medical physiology, which besides hypertension and muscle mass loss in chronic renal failure may explain many otherwise unexplainable phenomena in medicine. [ABSTRACT FROM AUTHOR]

Demand for Giant African Land Snail in Nigeria is so high such that it is very difficult to meet up with the supply as a protein source. However, during dry season, production at intensive level is often challenged with decline in growth and reproduction despite interventions to boost production. This study therefore evaluates the effect of zinc oxide on liveweight, reproductive organ dimensions and spermatozoa production of Giant African Land Snail (Archachatina marginata) during dry season. Thirty-two (32) snails with an average weight of 100 – 180 g were used for this experiment. The snails were allotted to four different feeding treatments which included concentrate diet only, concentrate +10 mg/kg of zinc oxide, concentrate +15 mg/kg of zinc oxide and concentrate +20 mg/kg of zinc oxide, respectively. Each treatment contained eight replicates. After nine weeks, five snails were selected from each treatment and dissected. Variables monitored were: weekly weight gain, shell circumference, shell length and shell diameter. Other reproductive data collected after dissections were: organ weight, reproductive tract weight, albumen weight, ovo-testis weight, gonado-somatic index (GSI) and spermatozoa concentration. The result showed that dietary zinc oxide significantly (P < 0.001) influenced feed intake, shell parameters, organ weight ovo-testis weight, albumen weight, gonado-somatic index, reproductive tract weight and spermatozoa concentration. Snailsfed zinc oxide supplemented diet had better shell measurements, organ weight, ovo-testis weight, albumen weight, gonadosomatic index and reproductive tract weight. Considering spermatozoa concentration, 10 mg/kg of zinc oxide inclusion into concentrate diet gave the highest concentration. The results of the present study showed that dietary zinc oxide positively influenced feed intake, shell measurements, organ weight, ovo-testis and albumen weight. Similarly, gonado-somatic index and spermatozoa production were also positively influenced. Therefore, 10 mg/kg inclusion of zinc oxide is recommended for better reproductive tract development, and spermatozoa production at the desirable economic level during the dry season production of Archachatina marginata.

Abstract Background Plasmodium falciparum malaria remains a leading cause of death in tropical regions of the world. Despite efforts to reduce transmission, rebounds associated with the persistence of malaria vectors have remained a major impediment to local elimination. One area that remains poorly understood is how Anopheles populations survive long dry seasons to re-emerge following the onset of the rains. Methods We developed a suite of mathematical models to explore the impact of different dry-season mosquito survival strategies on the dynamics of vector populations. We fitted these models to an Anopheles population data set from Mali to estimate the model parameters and evaluate whether incorporating aestivation improved the fit of the model to the observed seasonal dynamics. We used the fitted models to explore the impact of intervention strategies that target aestivating mosquitoes in addition to targeting active mosquitoes and larvae. Results Including aestivation in the model significantly improved our ability to reproduce the observed seasonal dynamics of vector populations as judged by the deviance information criterion (DIC). Furthermore, such a model resulted in more biologically plausible active mosquito survival times (for A. coluzzii median wet season survival time of 10.9 days, 95% credible interval (CrI): 10.0–14.5 days in a model with aestivation versus 38.1 days, 95% CrI: 35.8–42.5 days in a model without aestivation; similar patterns were observed for A. arabiensis). Aestivation also generated enhanced persistence of the vector population over a wider range of both survival times and fecundity levels. Adding vector control interventions that target the aestivating mosquito population is shown to have the potential to enhance the impact of existing vector control. Conclusions Dry season survival attributes appear to drive vector population persistence and therefore have implications for vector control. Further research is therefore needed to better understand these mechanisms and to evaluate the additional benefit of vector control strategies that specifically target dormant mosquitoes.