Can nesting behaviour allow reptiles to adapt to climate change?

A range of abiotic parameters within a reptile nest influence the viability and attributes (including sex, behaviour and body size) of hatchlings that emerge from that nest. As a result of that sensitivity, a reproducing female can manipulate the phenotypic attributes of her offspring by laying her eggs at times and in places that provide specific conditions. Nesting reptiles shift their behaviour in terms of timing of oviposition, nest location and depth of eggs beneath the soil surface across spatial and temporal gradients. Those maternal manipulations affect mean values and variances of both temperature and soil moisture, and may modify the vulnerability of embryos to threats such as predation and parasitism. By altering thermal and hydric conditions in reptile nests, climate change has the potential to dramatically modify the developmental trajectories and survival rates of embryos, and the phenotypes of hatchlings. Reproducing females buffer such effects by modifying the timing, location and structure of nests in ways that enhance offspring viability. Nonetheless, our understanding of nesting behaviours in response to climate change remains limited in reptiles. Priority topics for future studies include documenting climate-induced changes in the nest environment, the degree to which maternal behavioural shifts can mitigate climate-related deleterious impacts on offspring development, and ecological and evolutionary consequences of maternal nesting responses to climate change. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.

Past, present, and future predictions on the suitable habitat of the Slender racer (Orientocoluber spinalis) using species distribution models.

Species distribution models (SDMs) across past, present, and future timelines provide insights into the current distribution of these species and their reaction to climate change. Specifically, if a species is threatened or not well-known, the information may be critical to understand that species. In this study, we computed SDMs for Orientocoluber spinalis, a monotypic snake genus found in central and northeast Asia, across the past (last interglacial, last glacial maximum, and mid-Holocene), present, and future (2070s). The goal of the study was to understand the shifts in distribution across time, and the climatic factors primarily affecting the distribution of the species. We found the suitable habitat of O. spinalis to be persistently located in cold-dry winter and hot summer climatic areas where annual mean temperature, isothermality, and annual mean precipitation were important for suitable habitat conditions. Since the last glacial maximum, the suitable habitat of the species has consistently shifted northward. Despite the increase in suitable habitat, the rapid alterations in weather regimes because of climate change in the near future are likely to greatly threaten the southern populations of O. spinalis, especially in South Korea and China. To cope with such potential future threats, understanding the ecological requirements of the species and developing conservation plans are urgently needed.

Population origin, maternal effects, and hydric conditions during incubation determine embryonic and offspring survival in a desert-dwelling lizard.

While the effects of incubation environment on embryonic development and offspring traits have been extensively studied in oviparous vertebrates, studies into how genetic inheritance (population origin), maternal effects, and incubation environment interact to produce varying phenotypes, are rare. To elucidate the interactive role of those three factors during incubation in shaping offspring phenotypes through hydric conditions, we conducted a fully factorial experiment [arid and semiarid populations × maternal dry and wet treatments (MDT and MWT) × embryonic dry and wet treatments (EDT and EWT)] with a desert-dwelling lacertid lizard (Eremias argus). Female lizards in dry conditions produced larger clutch sizes but smaller eggs. The incubation period and hatching success were significantly affected by embryonic but not by maternal moisture treatments. Eggs in the EDT hatched later than those in the EWT in both arid and semiarid populations. Hatching success was lower in EDT than in EWT in the semiarid population, but not in the arid population. Hatchlings from the EDT had a slower post-hatch increase in body mass than those from the EWT. EDT would decrease the survival rates of hatchlings in the semiarid population only. In addition, structural equation models revealed that population had a stronger effect on embryonic and offspring survival than maternal and embryonic moisture. Our study demonstrates locally adaptive strategies of drought resistance at multiple life-history stages in lizard populations from diverse hydric habitats and highlights the importance of genetic factors in determining embryonic drought resistance in oviparous lizards.

Behavioural thermoregulation by the endangered crocodile lizard (Shinisaurus crocodilurus) in captivity.

Understanding the factors that may affect behavioural thermoregulation of endangered reptiles is important for their conservation because thermoregulation determines body temperatures and in turn physiological functions of these ectotherms. Here we measured seasonal variation in operative environmental temperature (Te), body temperature (Tb), and microhabitat use of endangered crocodile lizards (Shinisaurus crocodilurus) from a captive population, within open and shaded enclosures, to understand how they respond to thermally challenging environments. Te was higher in open enclosures than in shaded enclosures. The Tb of lizards differed between the open and shaded enclosures in summer and autumn, but not in spring. In summer, crocodile lizards stayed in the water to avoid overheating, whereas in autumn, crocodile lizards perched on branches seeking optimal thermal environments. Crocodile lizards showed higher thermoregulatory effectiveness in open enclosures (with low thermal quality) than in shaded enclosures. Our study suggests that the crocodile lizard is capable of behavioural thermoregulation via microhabitat selection, although overall, it is not an effective thermoregulator. Therefore, maintaining diverse thermal environments in natural habitats for behavioural thermoregulation is an essential measure to conserve this endangered species both in the field and captivity.

The Effect of Estrogen Replacement Therapy on Alzheimer's Disease and Parkinson's Disease in Postmenopausal Women: A Meta-Analysis.

Background: Estrogen replacement therapy (ERT) is a common treatment method for menopausal syndrome; however, its therapeutic value for the treatment of neurological diseases is still unclear. Epidemiological studies were performed, and the effect of postmenopausal ERT on treating neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), was summarized through a meta-analysis. Methods: Twenty-one articles were selected using a systematic searching of the contents listed on PubMed and Web of Science before June 1, 2019. Epidemiological studies were extracted, and relevant research data were obtained from the original articles based on the predefined inclusion criteria and data screening principles. The Comprehensive Meta-Analysis Version 2 software was used to pool effective size, test heterogeneity, conduct meta-regression and subgroup analysis, and to calculate publication bias. Results: Our results showed that ERT significantly decreased the risk of onset and/or development of AD [odds ratio (OR): 0.672; 95% CI: 0.581-0.779; P < 0.001] and PD (OR: 0.470; 95% CI: 0.368-0.600; P < 0.001) compared with the control group. A subgroup and meta-regression analysis showed that study design and measure of effect were the source of heterogeneity. Age, sample size, hormone therapy ascertainment, duration of the treatment, or route of administration did not play a significant role in affecting the outcome of the meta-analysis. Conclusion: We presented evidence here to support the use of estrogen therapy for the treatment of AD and PD.

Genetic diversity and inferred dispersal history of the Schlegel's Japanese Gecko (Gekko japonicus) in Northeast Asia based on population genetic analyses and paleo-species distribution modelling.

To understand the genetic diversity and dispersal history of Schlegel's Japanese gecko (Gekko japonicus), we performed genetic analyses and paleo-species distributional modelling. For the genetic analysis, we analyzed mitochondrial DNA (mtDNA) (cytochrome b [Cytb] and NADH dehydrogenase 2 [ND2]) and seven microsatellite loci of 353 individuals from 11 populations (2 east coast China, 4 west and central coast Japan and 5 Korea). For the paleo-species distribution modelling, we used 432 occurrence data points (125 China, 291 Japan and 16 Korea) over the Pleistocene and Holocene. China is inferred to be the source population, which had higher genetic diversity (mtDNA) and more private alleles (mtDNA) compared to Japanese and Korean populations. Differences between the three counties were very small in the mtDNA haplotype network despite some genetic structure among the three countries. Microsatellite analysis inferred that genetic exchange has actively occurred among the Chinese, Japanese and Korean populations. Suitable habitats in Japan should have been plentiful by the mid-Holocene, but have only recently become available in Korea. These results suggest that dispersal of G. japonicus occurred after the Holocene warming from the east coast of China to the west and central coasts of Japan and Korea, and gene flow is actively occurring among the three countries.

Mallotus oblongifolius extracts ameliorate ischemic nerve damage by increasing endogenous neural stem cell proliferation through the Wnt/ß-catenin signaling pathway.

Mallotus oblongifolius (MO), an edible medicinal plant from Hainan in China, shows a wide range of bioactivities. The daily consumption of MO or its extracts has been observed to ameliorate ischemic nerve injury. However the mechanisms remain unclear. In this study, the effects of MO both in vitro and in vivo were investigated. The results indicated that MO improved the motor ability, neurosensory ability, balance and grasping ability of mice with ischemic injuries, induced by bilateral common carotid artery ligation (BCCAL). In addition, MO improved the morphology of neurons, resisted the loss of neurons, and enhanced the content of the nestin protein in the cerebral cortex and subgranular zone (SGZ) area. Furthermore, in the oxygen-glucose deprivation and reperfusion (OGD/R) treated cell model, MO could effectively activate the Wnt/ß-catenin signaling pathway and promote the proliferation of neural stem cells (NSCs) and increase the protein expression levels of ß-catenin and CyclinD1. Our results suggest that Mallotus oblongifolius may be used as nutraceuticals or functional foods to alleviate ischemic nerve damage and promote recovery from ischemic stroke.

NKG2A is a NK cell exhaustion checkpoint for HCV persistence.

Exhaustion of cytotoxic effector natural killer (NK) and CD8+ T cells have important functions in the establishment of persistent viral infections, but how exhaustion is induced during chronic hepatitis C virus (HCV) infection remains poorly defined. Here we show, using the humanized C/OTg mice permissive for persistent HCV infection, that NK and CD8+ T cells become sequentially exhausted shortly after their transient hepatic infiltration and activation in acute HCV infection. HCV infection upregulates Qa-1 expression in hepatocytes, which ligates NKG2A to induce NK cell exhaustion. Antibodies targeting NKG2A or Qa-1 prevents NK exhaustion and promotes NK-dependent HCV clearance. Moreover, reactivated NK cells provide sufficient IFN-γ that helps rejuvenate polyclonal HCV CD8+ T cell response and clearance of HCV. Our data thus show that NKG2A serves as a critical checkpoint for HCV-induced NK exhaustion, and that NKG2A blockade sequentially boosts interdependent NK and CD8+ T cell functions to prevent persistent HCV infection.

The vulnerability of developing embryos to simulated climate warming differs between sympatric desert lizards.

The vulnerability of species to climate warming varies along latitudinal and elevational clines, but how sympatric species vary in vulnerability to climate warming remains largely unknown. We experimentally simulated nest temperatures of two sympatric lizards with divergent microhabitat preferences (Phrynocephalus przewalskii and Eremias argus), under climate warming senarios, to determine the response of embryos to increased mean temperatures and heat waves. Our study demonstrated that simulated climate warming reduced hatching success and hatchling size and growth in E. argus (that prefers closed microhabitats), but had less effect in P. przewalskii (that occupies open microhabitats). The reduced growth rate of E. argus hatchlings was associated with a decrease in metabolic rate, which was more evident in hatchling E. argus than in P. przewalskii. Our results suggest lizards that prefer closed microhabitats may be more vulnerable to climate warming than those that prefer open microhabitats; further studies are needed to test this hypothesis. More generally, the divergent responses of sympatric species to climate warming highlights the importance of distinguishing the thermal sensitivity of behavior and physiology for each species of a community, in order to make predictions about the impacts of climate warming at regional scales.

Food restriction affects maternal investment but not neonate phenotypes in a viviparous lizard.

Food availability significantly affects an animal's energy metabolism, and thus its phenotype, survival, and reproduction. Maternal and offspring responses to food conditions are critical for understanding population dynamics and life-history evolution of a species. In this study, we conducted food manipulation experiments in field enclosures to identify the effect of food restriction on female reproductive traits and postpartum body condition, as well as on hatchling phenotypes, in a lacertid viviparous lizard from the Inner Mongolian desert steppe of China. Females under low-food availability treatment (LFT) had poorer immune function and body condition compared with those under high-food availability treatment (HFT). The food availability treatments significantly affected the litter size and litter mass of the females, but not their gestation period in captivity or brood success, or the body size, sprint speed, and sex ratio of the neonates. Females from the LFT group had smaller litter sizes and, therefore, lower litter mass than those from the HFT group. These results suggest that female racerunners facing food restriction lay fewer offspring with unchanged body size and locomotor performance, and incur a cost in the form of poor postpartum body condition and immune function. The flexibility of maternal responses to variable food availability represents an important life strategy that could enhance the resistance of lizards to unpredictable environmental change.

Thermal ecology of three coexistent desert lizards: Implications for habitat divergence and thermal vulnerability.

How ectotherms exploit thermal resources has important implications for their habitat utilization and thermal vulnerability to climate warming. To address this issue, we investigated thermal relations of three sympatric lizard species (Eremias argus, Eremias multiocellata, and Phrynocephalus przewalskii) in the desert steppe of Inner Mongolia, China. We determined the thermoregulatory behavior, body temperature (T b), operative temperature (T e), selected body temperature (T sel), and critical thermal maximum (CTmax) of adult lizards. Based on these physiological parameters, we quantified the accuracy and effectiveness of thermoregulation as well as thermal-safety margin for these species. The three species were accurate and effective thermoregulators. The P. przewalskii preferred open habitats, and had a higher T b than the two Eremias lizards, which preferred shade habitats and shuttled more frequently between the shade and sun. This indicated that the three sympatric lizards have different thermoregulatory behavior and thermal physiology, which might facilitate their coexistence in the desert steppe ecosystem. In addition, the P. przewalskii had higher T sel and CTmax, and a wider thermal-safety margin than the two Eremias lizards, suggesting that the two Eremias lizards would be more vulnerable to climate warming than P. przewalskii.

Ellagic acid improves endogenous neural stem cells proliferation and neurorestoration through Wnt/ß-catenin signaling in vivo and in vitro.

SCOPE: The aim of this study is to research the effects of the polyphenol ellagic acid (EA) on brain cells and to explore its mechanism of action, and to evaluate whether EA can be safely utilized by humans as a functional food or therapeutic agent. METHODS AND RESULTS: A photothrombosis-induced model of brain injury in rats was created, and EA was administered intragastrically to rats on 7 consecutive days post-venous ischemia. An oxygen-glucose deprivation and re-perfusion model was established in neural stem cells in order to research the effects on proliferation after 2 days of EA treatment in vitro. The administration of EA improved the rats' nerve-related abilities, remedied infarct volumes and morphological changes in the brain, and enhanced the content of nestin protein in the brain semidarkness zone. The proliferation of NSCs and the expression of ß-catenin and Cyclin D1 genes were also increased in primary cultured NSCs. CONCLUSIONS: EA administration can improve brain injury outcomes and increase the proliferation of NSCs through the Wnt/ß-catenin signaling pathway. The presented results represent new insights on the mechanisms of the brain cell protective activity of EA. Thus, EA may be used in functional foods or medicines to help treat nerve dysfunction, neurodegenerative disease and aging.

The effects of light exposure during incubation on embryonic development and hatchling traits in lizards.

Light is an environmental factor that is known to profoundly affect embryonic development in some oviparous vertebrates, but such effects are unstudied in reptiles. We investigated the light sensitivity of lizard embryos by examining the thickness and light transmittance of eggshells as well as the effect of light on embryonic development and hatchling traits in four lizard species, the Chinese skink (Plestiodon chinensis), the northern grass lizard (Takydromus septentrionalis), the oriental leaf-toed gecko (Hemidactylus bowringii) and the Japanese gecko (Gekko japonicus). The eggshells were thinner and thus had higher light transmittance in Chinese skink than the other three species. Light exposure during incubation significantly accelerated the embryonic development in all species, with higher light intensity resulting in faster embryonic development. Interestingly, light stimulation negatively influenced hatchling size and survival in skinks, but had no effect in lacertids and geckos. This interspecific discrepancy not only relates to the differences in thickness and light transmittance of eggshells, but might also reflect the differences in the reproductive habits of these species. Given the diversity of light conditions that reptile embryos face during development, studies on the response of reptile embryos to light may offer a unique opportunity to understand the mechanisms of embryonic light sensitivity in animals.

Low precipitation aggravates the impact of extreme high temperatures on lizard reproduction.

Extreme high temperatures are occurring more frequently with ongoing anthropogenic climate warming, but the experimental tests of the effects of high temperatures on terrestrial vertebrates in natural conditions are rare. In this study, we investigated the effects of extreme high temperatures on female reproduction and offspring traits of multi-ocellated racerunners (Eremias multiocellata) kept in field enclosures in the desert steppe of Inner Mongolia. Our studies indicate that high temperatures significantly affect the gestation period and reproductive output of females and the offspring sex ratio, but have little impact on offspring body size and mass. More interestingly, we found that the effect of extreme high temperatures on female reproductive output was not consistent between two consecutive years that differed in precipitation. Low precipitation may aggravate the impact of climate warming on lizards and negatively affect the survival of lizards in the desert steppe. Our results provide evidence that temperature interacts with precipitation to determine the life history of lizards, and they suggest that a drier and hotter environment, such as the future climate in arid mid-latitude areas, will likely impose severe pressure on lizard populations, which are an important component of the food web in desert areas around the world.

Maternal thermal environment induces plastic responses in the reproductive life history of oviparous lizards.

Adaptive plasticity may shift phenotypic traits close to a new optimum for directional selection and probably facilitates adaptive evolution in new environments. However, such plasticity has rarely been reported in life-history evolution, despite overwhelming evidence of life-history variation both among and within species. In this study, the temperatures experienced by gravid females of Scincella modesta were manipulated to identify maternally induced plasticity in reproductive traits and the significance of such changes in the evolution of life history. Consistent with the geographic pattern of life history, the study demonstrated that low temperatures delayed egg oviposition, resulting in a more advanced embryonic developmental stage at oviposition and shorter incubation periods compared with warm temperatures. In addition, females maintained at low temperatures produced larger eggs and hence heavier hatchlings than those at warm temperatures. This study demonstrated that environmental temperatures can induce plastic responses in egg retention and offspring size, and these maternally mediated changes in reproductive life history seem to be adaptive in the light of latitudinal clines of these traits in natural populations.

[Prevention against and treatment of doxorubicin-induced acute cardiotoxicity by dexrazoxane and schisandrin B].

In this study, it is to compare the effectiveness of prevention against and treatment of doxorubicin (DOX) induced cardiotoxicity by dexrazoxane and schisandrin B (Sch B) in rats. Sprague-Dawley (SD) rats were randomly divided into the following 6 groups: normal saline group, DOX group, DOX+DEX group, DOX+Sch B (80 mg x kg(-1)) group, DOX+Sch B (40 mg x kg(-1)) group and DOX+Sch B (20 mg x kg(-1)) group. The results showed that Sch B could combat the increase of myocardial enzymes in peripheral blood, decrease of the enzyme activity of myocardial tissue antioxidant enzymes and disorders of systolic and diastolic function of heart in rats intravenously injected with doxorubicin (15 mg x kg(-1)). Sch B was better than DEX in protecting rat against DOX-induced the symptoms. Sch B could protect rat against DOX-induced acute cardiomyopathy and has clinical potential applications.

Different mechanisms lead to convergence of reproductive strategies in two lacertid lizards (Takydromus wolteri and Eremias argus).

Life history traits may vary within and among species. Rarely, however, are both variations examined concurrently to identify the life history adaptation. We found that female body size, offspring number and size, and incubation period showed convergent evolution in two lacertid lizards (Takydromus wolteri and Eremias argus) that occur sympatrically in high-latitude and low-latitude localities. Females from the high-latitude population were larger and produced larger clutches than those from the low-latitude population. In both species, the incubation period was shorter for the high-latitude population than for the low-latitude population. However, the physiological mechanism underlying the shorter incubation period differed between the species. These results suggest that: (1) sympatric lizards may adopt similar reproductive strategies in response to their common environments, and (2) embryonic development of the two species follows different pathways for adaptation to low temperatures. This study highlights the importance of understanding the adaptive evolution of life history in response to environmental changes at the embryonic life stages.

Relationships of sleep duration with sleep disturbances, basic socio-demographic factors, and BMI in Chinese people.

OBJECTIVE: This study aimed at determining the mean total sleep time (TST) and the relationship between sleep duration and basic socio-demographic factors and BMI sleep problems in Chinese subjects. METHOD: A total of 5926 subjects were randomly selected and interviewed using standardized assessment tools. RESULTS: The reported mean TST was 7.76 h. Short sleepers were significantly older than medium and long sleepers. There were more urban residents who were short sleepers than medium and long sleepers. Short sleepers reported more sleep problems than medium and long sleepers. Short and long sleepers reported more psychiatric disorders than medium sleepers in both sexes, and short sleepers also had more major medical conditions in women. Short sleepers had a lower BMI than medium and long sleepers after controlling for the effects of age and psychiatric disorders in women. CONCLUSIONS: Nationwide epidemiologic surveys in China are needed to further explore the relationship between sleep duration and sleep problems.

Generalized anxiety disorder in China: prevalence, sociodemographic correlates, comorbidity, and suicide attempts.

PURPOSE: This study aims to determine the 12-month and lifetime prevalence of generalized anxiety disorder (GAD) and its sociodemographic correlates. DESIGN AND METHODS: A total of 5,926 subjects were randomly selected and interviewed. FINDINGS: The overall 12-month and lifetime prevalence of GAD was 0.8%, and 1.2%, respectively. Being older than 25 years and female, lower education level, unemployed status, and lower (RMB2000/month) monthly income were associated with increased risk of GAD. PRACTICE IMPLICATIONS: The low percentage of subjects treated for GAD indicates a major public health problem that should be addressed.

Alcohol-related disorders in Beijing, China: prevalence, socio-demographic correlates, and unmet need for treatment.

BACKGROUND: The study aimed to determine the prevalence of alcohol use, episodic heavy drinking, and alcohol dependence and their socio-demographic correlates in Beijing, China. methods: A total of 5,926 subjects were randomly selected in Beijing and interviewed using the Composite International Diagnostic Interview (CIDI 1.0). Data on basic socio-demographic and current major medical conditions were also collected. RESULTS: The 12-month prevalence of alcohol use and episodic heavy drinking were 32.5 and 13.8%, respectively. The 12-month and lifetime prevalence of alcohol dependence were 1.7 and 4.3%, respectively. Age above 24 years, male sex, being married and employed, low education level (junior high school, primary school or illiterate), rural residence, and having comorbid psychiatric disorders were all significantly associated with a higher likelihood of alcohol-related disorders. Only 2.4% of the subjects with alcohol dependence were receiving treatment, and a mere 1.4% had sought treatment from mental health professionals. CONCLUSIONS: Nationwide surveys are urgently needed to further explore the prevalence of alcohol-related disorders in China.