Eremias Multiocellata Research Articles

Transcriptomic profiling revealed immune-related signaling pathways in response to experimental infection of Leishmania donovani in two desert lizards from Northwest China

Little is known about the immune response of lizards to Leishmania parasties. In this study, we conducted the first liver transcriptome analysis of two lizards (Phrynocephalus przewalskii and Eremias multiocellata) challenged with L. donovani, endemic to the steppe desert region of northwestern China. Our results revealed that multiple biological processes and immune-related signaling pathways are closely associated with the immune response to experimental L. donovani infection in the two lizards, and that both lizards show similar changes to mammals in terms of immunity to Leishmania. However, the interspecific divergence of the two lizards leads to different transcriptomic changes. In particular, in contrast to P. przewalskii, the challenged E. mutltiocellata was characterized by the induction of down-regulation of most DEGs. These findings will contribute to the scarce resources on lizard immunity and provide a reference for further research on immune mechanisms in reptiles.

Gut microbiota modulation enhances the immune capacity of lizards under climate warming

BackgroundHost-microbial interactions are expected to affect species’ adaptability to climate change but have rarely been explored in ectothermic animals. Some studies have shown that short-term warming reduced gut microbial diversity that could hamper host functional performance.ResultsHowever, our longitudinal experiments in semi-natural conditions demonstrated that warming decreased gut microbiota diversity at 2 months, but increased diversity at 13 and 27 months in a desert lizard (Eremias multiocellata). Simultaneously, long-term warming significantly increased the antibacterial activity of serum, immune responses (higher expression of intestinal immune-related genes), and the concentration of short-chain fatty acids (thereby intestinal barrier and immunity) in the lizard. Fecal microbiota transplant experiments further revealed that increased diversity of gut microbiota significantly enhanced antibacterial activity and the immune response of lizards. More specifically, the enhanced immunity is likely due to the higher relative abundance of Bacteroides in warming lizards, given that the bacteria of Bacteroides fragilis regulated IFN-β expression to increase the immune response of lizards under a warming climate.ConclusionsOur study suggests that gut microbiota can help ectotherms cope with climate warming by enhancing host immune response, and highlights the importance of long-term studies on host-microbial interactions and their biological impacts.Graphical 6GDSteHzeFBZdjTKmE1qYrVideo

Climate warming has divergent physiological impacts on sympatric lizards

Climate warming is expected to affect the vulnerability of sympatric species differentially due to their divergent traits, but the underlying physiological mechanisms of those impacts are poorly understood. We conducted field warming experiments (present climate vs. warm climate) using open-top chambers to determine the effects of climate warming on active body temperature, oxidative damage, immune competence, growth and survival in two sympatric desert-dwelling lizards, Eremias multiocellata and Eremias argus from May 2019 to September 2020. Our climate warming treatment did not affect survival of the two species, but it did increase active body temperatures and growth rate in E. multiocellata compared to E. argus. Climate warming also induced greater oxidative damage (higher malondialdehyde content and catalase activity) in E. multiocellata, but not in E. argus. Further, climate warming increased immune competence in E. multiocellata, but decreased immune competence in E. argus, with regards to white blood cell counts, bacteria killing ability and relative expression of immunoglobulin M. Our results suggest that climate warming enhances body temperature, and thereby oxidative stress, immune competence and growth in E. multiocellata, but decreases immune competence of E. argus, perhaps as a cost of thermoregulation to maintain body temperatures under climate warming. The divergent physiological effects of climate warming on sympatric species may have profound ecological consequences if it eventually leads to changes in reproductive activities, population dynamics and community structure. Our study highlights the importance of considering interspecific differences in physiological traits when we evaluate the impact of climate warming on organisms, even for those closely-related species coexisting within the same geographical area.

Sex-Linked Loci on the W Chromosome in the Multi-Ocellated Racerunner (Eremias multiocellata) Confirm Genetic Sex-Determination Stability in Lacertid Lizards.

The multi-ocellated racerunner, Eremias multiocellata, was considered to have temperature-dependent sex determination (TSD), as its sex ratio can be influenced at different temperatures. However, such an observation contrasts with recent findings that suggest TSD is less common than previously thought. Here, a genotyping-by-sequencing (GBS) approach was employed to identify sex-linked markers in the E. multiocellata, for which the mechanism choice of TSD or GSD is still controversial. We preliminarily identified 119 sex-linked markers based on sex-associated sex-specific sequences, 97% of which indicated female heterogamety. After eliminating the false positives, 38 sex-linked markers were recognized, all of which showed the ZW/ZZ system. Then, eight of the novel markers were verified by PCR amplification from 15 populations of E. multiocellata, which support the GSD in E. multiocellata without geographic variation. To test the conservation of sex chromosome in Eremias, the eight markers were further cross-tested by PCR amplification in 10 individuals of the Mongolian racerunner (Eremias argus), two of which exhibited cross-utility. The novel sex-linked markers could be mapped on the W chromosome of the sand lizard (Lacerta agilis). Our finding that the sex-linked markers are shared in closely related species, along with a conserved synteny of the W chromosome, further supports the homology and conservation of sex chromosomes in the lacertid lizards.

Telomere length, oxidative stress and their links with growth and survival in a lizard facing climate warming

Higher temperatures enhance ectothermic metabolism and development, which can reduce individual health and life expectancy, and therefore increase their vulnerability to climate warming. However, the mechanistic causes and consequences of such a temperature-driven impact remain unclear. Our study aimed to address two questions: (1) does climate warming alter early-life growth and physiology, and, if so, what are the associated carry-over effects in terms of reduced survival, increased oxidative stress and telomere shortening? (2) can oxidative stress and telomere dynamics at early life stages predict the effect of climate warming on individual survival? To answer these questions, we conducted a longitudinal experiment under semi-natural conditions where we exposed multiocellated racerunner (Eremias multiocellata) to warming conditions from juvenile to adult stages. We found that exposure to climate warming enhanced growth rates, induced oxidative stress, and shortened telomere length of juvenile lizards. Warming conditions did not induce carry-over effects in terms of altered growth rate or physiology but resulted in increased mortality risk in the later life. Intriguingly, telomere shortening in young individuals was associated with mortality risk later in life. This study improves our mechanistic understanding of how global warming impacts on ectotherms' life-history traits, which encourages the inclusion of physiological information in assessing species vulnerability to climate change.

Seasonal flexibility of kidney structure and factors regulating water and salt in Eremias multiocellata

Although sodium and water reabsorption by the kidney plays a major role in maintaining body fluid homeostasis, the seasonal response of renal morphology and the factors involved in water and salt regulation are not well known, especially in reptiles. Eremias multiocellata is a typical desert-dwelling lizard. Here, we compared water and salt regulation of E. multiocellata in winter (hibernation), spring (emerging from hibernation), and summer (active) according to histomorphometry and the expression of genes such as those encoding aquaporins (AQP1, AQP2, AQP3), the Na+-Cl− cotransporter (NCC), the Na+-K+-2Cl− cotransporter (NKCC2), renin (Ren), angiotensin II receptor type 2 (AT2R), and endothelial nitric oxide synthase (eNOS) in the kidneys. The results showed that the area of Bowman's capsule and the glomerular density were lower in winter compared to summer and spring, and the lumen size of the DCT, PCT, and IS was greater in spring than in summer. Compared to summer and spring, the expression of AQP1, AQP3, NCC, NKCC2, Ren, and eNOS was significantly decreased in winter, whereas the expression of AQP2 and AT2R remained high. These results indicate that E. multiocellata balances its water budget via morpho-functional changes in different seasons. Although renal function was temporarily attenuated during winter, the regulation of aquaporins genes was not synchronous, indicating the complexity and particularity of water and salt regulation in desert lizards when facing the constraints of harsh environmental conditions, seasonal variations, and hibernation. These results will enrich the understanding of water and salt regulation mechanisms in desert reptiles.

Integrative Taxonomy within Eremias multiocellata Complex (Sauria, Lacertidae) from the Western Part of Range: Evidence from Historical DNA.

The Kokshaal racerunner, Eremias kokshaaliensis Eremchenko et Panfilov, 1999, together with other central Asian racerunner species, is included in the Eremias multiocellata complex. In the present work, for the first time, the results of the analysis of historical mitochondrial DNA (barcode) are presented and the taxonomic status and preliminary phylogenetic relationships within the complex are specified. We present, for the first time, the results of the molecular analysis using historical DNA recovered from specimens of several species of this complex (paratypes of the Kokshaal racerunner and historical collections of the Kashgar racerunner E. buechneri from Kashgaria) using DNA barcoding.

Grow fast but don't die young: Maternal effects mediate life-history trade-offs of lizards under climate warming.

As postulated by life-history theory, not all life-history traits can be maximized simultaneously. In ectothermic animals, climate warming is predicted to increase growth rates, but at a cost to overall life span. Maternal effects are expected to mediate this life-history trade-off, but such effects have not yet been explicitly elucidated. To understand maternal effects on the life-history responses to climate warming in lizard offspring, we conducted a manipulative field experiment on a desert-dwelling viviparous lacertid lizard Eremias multiocellata, using open-top chambers in a factorial design (maternal warm climate and maternal present climate treatments×offspring warm climate and offspring present climate treatments). We found that the maternal warm climate treatment had little impact on the physiological and life-history traits of adult females (i.e. metabolic rate, reproductive output, growth and survival). However, the offspring warm climate treatment significantly affected offspring growth, and both maternal and offspring warm climate treatments interacted to affect offspring survival. Offspring from the warm climate treatment grew faster than those from the present climate treatment. However, the offspring warm climate treatment significantly decreased the survival rate of offspring from maternal present climate treatment, but not for those from the maternal warm climate treatment. Our study demonstrates that maternal effects mediate the trade-off between growth and survival of offspring lizards, allowing them to grow fast without a concurrent cost of low survival rate (short life span). These findings stress the importance of adaptive maternal effects in buffering the impact of climate warming on organisms, which may help us to accurately predict the vulnerability of populations and species to future warming climates.

Records of three mammal tick species parasitizing an atypical host, the multi-ocellated racerunner lizard, in arid regions of Xinjiang, China

BackgroundTicks are ectoparasites that feed on blood of a broad taxonomical range of terrestrial and flying vertebrates and are distributed across a wide range of environmental settings. To date, the species identity, diversity, and relationships among the ticks on lizards in China have been poorly understood.MethodsIn this study, 30 ticks, collected from the multi-ocellated racerunner (Eremias multiocellata) lizard in the Tarim Basin and adjacent Yanqi Basin of the Xinjiang Uygur Autonomous Region in China, were identified by morphological observation and confirmed by DNA-based techniques. The mitochondrially encoded 12S rRNA, 16S rRNA, and COI gene fragments of ticks were amplified and sequenced. To understand the genetic polymorphisms, 47 ticks collected from hedgehogs and 1 from brushwood in the Tarim Basin were also included. Species identification was based on both morphological and molecular characters. The median-joining network approach was used to evaluate the intraspecific genealogies of the ticks and their relatedness with the geographical origin or hosts.ResultsThe sequence similarity analysis confirmed that the 30 ticks belong to three genera and three species including 11 individuals of Hyalomma asiaticum, 3 of Rhipicephalus turanicus, and 16 of Haemaphysalis sulcata. A network approach revealed paraphyletic populations of R. turanicus and Hy. asiaticum at the intraspecies level regarding geographical origin and low host specificity. For R. turanicus and Hy. asiaticum, common ancestry was observed between COI sequences from lizards and other sequence types from different hosts and countries.ConclusionsTo our knowledge, our study is the first to conduct a molecular survey of ticks from lizards in the arid regions of Xinjiang, China. Eremias multiocellata is an atypical host of the three tick species. Notably, two species of ticks, Hy. asiaticum and R. turanicus, have been collected and identified from lizards in China for the first time. Star-like networks suggest both of them might have experienced recent population expansion. The discoveries are closely related to the geographical environments in Xinjiang and will provide information for the control of ticks and tick-borne pathogens in Northwest China.Graphical

A staging table of embryonic development for a viviparous (live-bearing) lizard Eremias multiocellata (Squamata: Lacertidae).

As the only viviparous reptile in China that has both temperature-dependent sex determination (TSD) and genetic-dependent sex determination (GSD) mechanisms, Eremias multiocellata is considered as an ideal species for studying the sex determination mechanism in viviparous lizards. However, studies on embryonic stage of viviparous lizards and morphological characteristics of each stage are limited. In the present study, the embryonic development process of E. multiocellata is divided into 15 stages (stages 28-42) according to the morphology of embryos. Embryos sizes are measured and continuous dynamic variation of some key features, including limbs, genitals, eyes, pigments, and brain scales are color imaged by a stereoscopic microscope. Furthermore, based on these morphological characteristics, we compare the similarities and differences in the embryonic development of E. multiocellata with other squamate species. Our results not only identified the staging table of E. multiocellata with continuous changes of external morphological characteristics but also developed a staging scheme for an important model species that provides a necessary foundation for study of sex determination in a viviparous lizard.

Experimental warming induces oxidative stress and immunosuppression in a viviparous lizard, Eremias multiocellata.

Reptiles are especially vulnerable to climate warming because their behavior, physiology, and life history are highly dependent on environmental temperature. In this study, we envisaged new probable mechanisms underlying the high vulnerability of lizards, wherein heat exposure induces oxidative stress and leads to immunosuppression. To test this hypothesis, we conducted a warming experiment on a lizard (Eremias multiocellata) from a desert steppe in Inner Mongolia from May to September using open-top chambers set up in their natural habitat and compared the components of oxidative stress (antioxidant ability [Superoxide dismutase (SOD) activity], extent of oxidative damage [malondialdehyde (MDA) content]), and immunocompetence (white blood cells [WBC] counts and immunoglobulin M [IgM] expression) between the warming and control groups. At the end of the experiment, the warming treatment did not affect the survival rate of the lizards. However, MDA content, but not SOD activity, was significantly higher in the warming group than in the control group. The WBC counts and IgM expression were significantly lower in the warming group than in the control group. Our results verified our hypothesis and provided novel cues and methods for the investigation of the mechanisms behind the high probability of extinction of other ectotherms under warming conditions.

Next-generation sequencing yields a nearly complete mitochondrial genome of the Multiocellated Racerunner (Eremias multiocellata) in Northwest China

The viviparous Multiocellated Racerunner, Eremias multiocellata, is widespread in North China, Mongolia, and the Tuva Republic of Russia. A nearly complete mitochondrial genome of one individual from the suburb of Jingyuan County in Northwest China was determined by next-generation sequencing. The mitogenome is 17,333 bp in size, comprising 2 ribosomal RNA genes, 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and one control region. The gene arrangement and composition is similar to the typical mitochondrial DNA of vertebrates. With exception to the control region, all of the 37 genes were completely recovered. The concatenated PCGs were used to conduct Bayesian phylogenetic analyses together with several related lizards with mitogenome data in GenBank. The resulting phylogenetic tree confirmed the monophyly of both genus Eremias and its viviparous group. The mitogenome sequence will provide fundamental data for resolving phylogenetic and genetic problems related to Eremias viviparity.

Phenotypic plasticity may help lizards cope with increasingly variable temperatures.

Temperature variability is predicted to increase in the coming century due to climate change. However, the biological impact of increased temperature variability on animals remains largely unexplored. Here, we experimentally exposed gravid viviparous lizards (Eremias multiocellata) to two thermal environments [constant daily maximum (CDM) versus variable daily maximum (VDM) treatment with the same average temperature] to address maternal and offspring responses to increased variability in ambient temperature. Females from the VDM treatment delayed parturition, but produced similar litter sizes and litter masses as did CDM females. Offspring from the VDM treatment selected higher body temperatures, had higher metabolic rates and higher growth rates, and grew to a similar size as those from the CDM treatment despite having a shorter growth period prior to hibernation. Therefore, phenotypic plasticity may be critical for lizards to respond effectively to climate change, and its role in responding to increasingly variable temperatures warrants further attention.

Maternal food availability affects offspring performance and survival in a viviparous lizard

Summary Whether maternal effects are adaptive or not has been a long‐standing topic of discussion in evolutionary ecology. The effects of maternal diet on offspring have been addressed by several studies on diverse organisms, but results are typically conflicting or inconclusive. In this study, we conducted food manipulation experiments with a factorial design (high and low maternal food conditions × high and low offspring food conditions) in a viviparous lacertid lizard (Eremias multiocellata) to test four competing hypotheses on the evolutionary significance of maternal effects: environmental matching hypothesis, low‐food compensation hypothesis, low‐food pathology hypothesis and no‐compensation hypothesis. We found that offspring under the maternal low‐food treatment had higher growth and survival rates than those under the maternal high‐food treatment, supporting the low‐food compensation hypothesis rather than the environmental matching hypothesis, which has been widely accepted as an explanation for the adaptive significance of maternal effects. Our study highlights the importance of testing multiple competing hypotheses that involve both adaptive and non‐adaptive explanations when studying the evolutionary significance of phenotypic plasticity. A lay summary is available for this article.

Influence of rat drug containing serum of Ningxia Eremias multiocellata on human gastric cancer BCG-823 cell proliferation and apoptosis

Influence of rat drug containing serum of Ningxia <i>Eremias multiocellata</i> on human gastric cancer BCG-823 cell proliferation and apoptosis

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.

Patterns of Embryonic Nutrition and Characteristics of Chorioallontoic Placenta in a Viviparous Racerunner Lizard, Eremias multiocellata : a Preliminary Study

In this study we observed the embryonic development processes and compared the weight of eggs with neonates to identify the form of nutritional provisioning in Eremias multiocellata . We also used light microscopy to determine the features of chorioallontoic placenta during late stages of gestation. Neonatal dry weight was approximately 10.3% smaller than egg dry weight. Chorioallantoic membrane and uterine epithelium exhibited an indirect apposition without any fusion. No specialized region, placentome, has been found for nutrition transfer between these membranes. The chorioallontoic placenta of E. multiocellata is consistent with the simplest and most common type, Weekes type I. We infer that E. multiocellata is predominately lecithotrophic, meaning that nourishment for embryonic development is primarily supplied by the yolk. This kind of embryonic nutrition confirms the pattern found in most squamates with a simple placenta. This simple placenta adds anatomical evidence to understand the weak immune interaction between matrix and fetus in E. multiocellata . Finally, we discussed the implications for interpreting the evolution of viviparity and placentation.

Identification of Sex Chromosomes by Means of Comparative Genomic Hybridization in a Lizard, Eremias multiocellata.

Eremias multiocellata is a viviparous lizard that is known to exhibit temperature-dependent sex determination (TSD). Conventional Giemsa staining under light microscope examination has identified the karyotype of this species to be 2 n=36 I+2 m, with no detectable heteromorphic sex chromosomes. However, a highly differentiated female-specific chromosome, W, which is homomorphic with the Z chromosome, is found in the present study by the high-resolution cytogenetic method of comparative genomic hybridization (CGH). The results show that E. multiocellata is a viviparous lizard with both TSD and ZW heterogametic sex chromosomes. Despite the fact that a different sex ratio of male offspring was found in two populations (separated by an altitude of 1400 m) in previous incubation experiments, we demonstrate, using genomic in situ hybridization (GISH), that there is no significant chromosomal loss or acquisition between the two populations. This suggests that temperature may play a more important role in lowland populations. These results most likely indicate that E. multiocellata is transitioning between the evolutionary processes of TSD and genotypic sex determination (GSD) systems, and also give clues to the effect of TSD versus GSD in this process.

MHC Class I Exon 4 in the Multiocellated Racerunners (Eremias multiocellata): Polymorphism, Duplication and Selection

The major histocompatibility complex (MHC) is a dynamic genetic region with an essential role in the adaptive immunity of jawed vertebrates. The MHC polymorphism is affected by many processes such as birth-and-death evolution, gene conversion, and concerted evolution. Studies investigating the evolution of MHC class I genes have been biased toward a few particular taxa and model species. However, the investigation of this region in non-avian reptiles is still in its infancy. We present the first characterization of MHC class I genes in a species from the family Lacertidae. We assessed genetic diversity and a role of selection in shaping the diversity of MHC class I exon 4 among 37 individuals of Eremias multiocellata from a population in Lanzhou, China. We generated 67 distinct DNA sequences using cloning and sequencing methods, and identified 36 putative functional variants as well as two putative pseudogene-variants. We found the number of variants within an individual varying between two and seven, indicating that there are at least four MHC class I loci in this species. Gene duplication plays a role in increasing copy numbers of MHC genes and allelic diversity in this species. The class I exon 4 sequences are characteristic of low nucleotide diversity. No signal of recombination is detected, but purifying selection is detected in beta 2-microglobulin interaction sites and some other silent sites outside of the function-constraint regions. Certain identical alleles are shared by Eremias multiocellata and E. przewalskii and E. brenchleyi, suggesting trans-species polymorphism. The data are compatible with a birth-and-death model of evolution.

Characterisation and Expression Analysis of Sox9 in the Multiocellated Racerunner,Eremias multiocellata

Sox9 is an important member of Sox family which is involved in a variety of developmental processes including sex determination and gonadal differentiation. The cDNA of Sox9 from multiocellated racerunner E. multiocellata was cloned using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The sequence contains a 1497 bp open reading frame, which encodes a 498 amino acid protein with a predicted molecular weight of 55.45 kDa. EmSox9 displays high similarity to those of reptiles, and shows an overall amino acid identity of >82%. We also investigated the tissue-specific expression of EmSox9 mRNA by real-time quantitative PCR. Sox9 mRNA is present in brain, heart, liver, kidney, gonads and muscle tissues of adult E. multiocellata, with the highest expression in brain and testis. The results indicate that Sox9 may play important roles in some tissues during E. multiocellata neural and gonadal development.