We investigated how exposure duration （time that two individuals initially interact） and separation interval （time be- tween the initial interaction and a subsequent interaction） affect recognition memory of consp...We investigated how exposure duration （time that two individuals initially interact） and separation interval （time be- tween the initial interaction and a subsequent interaction） affect recognition memory of conspecifics in male red-backed sala- manders Plethodon cinereus. Previous studies have demonstrated that this species aggressively defends territories. We recorded aggressive behavior to assess recognition memory, because aggression is more intense toward previously unencountered indi- viduals compared to previously encountered individuals in this species. We found that with 15-min exposures and 5-day separa- tion intervals, focal males did not spend significantly more time threatening ＇unfamiliar＇ intruders than ＇familiar＇ intruders. After either 8-hour exposures and 5-day separation intervals and 5-day exposures and 5-day separation intervals, focal males spent sig- nificantly more time threatening unfamiliar intruders than familiar intruders. These results suggest that male red-backed salaman- ders can remember familiar conspecifics （e.g., territorial neighbors） after at least an 8-hour exposure duration and that memory persists at least as long as 5 days. After 5-day exposure and 15-day separation intervals, we found no significant difference in ag- gressive behavior toward familiar and unfamiliar intruders. Long separation intervals （15 days） may lead either to loss of memory of previously familiar individuals or, alternatively, aggressive reassessment of individuals as only a change in behavior indicates positively that memory has occurred. Thus, variance in territorial defense within an individual may depend on its ability to recog- nize conspecific males .展开更多
Currently nine families of tailed amphibians, including 682 species, are recognised in the world. Five of these families, including some 166 species, occur in the Old World （Europe, Asia, and Northern Africa）. The f...Currently nine families of tailed amphibians, including 682 species, are recognised in the world. Five of these families, including some 166 species, occur in the Old World （Europe, Asia, and Northern Africa）. The family of hynobiid salamanders （hynobiidae） is endemic to this region, whereas the other families also are represented in the New World （America）. Salamanders of the Old Worm is a comprehensive monograph authored by Max Sparreboom. With this book, which aims to be an up- date of Robert Thorn＇s book of 1969, the author presents updated information on salamander species diversity in this region. The book is bound to become a classic in its field： it contains descriptions of all five families and 166 salamander species, a taxonomical diagnosis, distribution maps, and a wealth of information on habitat preferences, behaviour, threats, conservation, etc. Every species chapter is followed by a comment by the author and references to technical literature. For many species the biological information comes from the author himself, who made observations of behaviour in aquariums and in the field. This knowledge is supplemented with information from the scientific literature, which is synthesized in a systematic way. What will especially appeal to the reader is the great number of beautiful pictures in the text, showing details of morphological characters, habitat and bebaviour in the different life history stages. These features add to the value of the book, both in scientific and artistic aspects.展开更多
Salamanders are unique among tetrapods in their ability to regenerate the limbs throughout life.Like other poikilothermic amphibians,salamanders also show a remarkable capacity to survive long periods of starvation.Wh...Salamanders are unique among tetrapods in their ability to regenerate the limbs throughout life.Like other poikilothermic amphibians,salamanders also show a remarkable capacity to survive long periods of starvation.Whether the physiological reserves necessary for tissue regeneration are preserved or sacrificed in starved salamanders is unknown.In the current study,we maintained Iberian ribbed newts(Pleurodeles waltl)under extreme physiological stress to assess the extent of regeneration and identify the molecular and cellular changes that may occur under such conditions.After 19 months of complete food deprivation,the animals exhibited extensive morphological and physiological adaptations but remained behaviorally active and vigilant.Autophagy was elevated in different tissues and the transformed gut microbiota indicated remodeling of the intestinal tract related to autophagy.Upon limb amputation in animals starved for 21 months,regeneration proceeded with progenitor cell proliferation and migration,leading to limb blastema formation.However,limb outgrowth and patterning were substantially attenuated.Blockage of autophagy inhibited cell proliferation and blastema formation in starved animals,but not in fed animals.Hence,tissue autophagy and the regenerative response were tightly coupled only when animals were under stress.Our results demonstrate that under adverse conditions,salamanders can exploit alternative strategies to secure blastema formation for limb regeneration.展开更多
Throughout the animal kingdom there are species that have two or more phenotypic forms or ‘morphs＇, and many of these are amphibians. In North America, the red-backed salamander Plethodon cinereus can have either a ...Throughout the animal kingdom there are species that have two or more phenotypic forms or ‘morphs＇, and many of these are amphibians. In North America, the red-backed salamander Plethodon cinereus can have either a red dorsal stripe or no dorsal stripe （lead-phase form）, and evidence to date indicates the lead-phase form incurs a greater number of attacks from predators. In a recent collection of 51 P cinereus, blood smears of both color morphs （35 red-stripe, 16 lead-phase） were examined to obtain numbers of circulating leukocytes （via light microscopy）, which can be used to indirectly estimate levels of stress hormones in vertebrates via a ‘hematological stress index＇, which is the ratio between the number of two leukocyte types （neutrophils and lymphocytes）. Our results showed that lead-phase salamanders tended to have greater numbers of circulating neutrophils and lower numbers of circulating lymphocytes than red-stripe morphs, leading to higher average neutrophil-lymphocyte ratios in lead-phase individuals. Since the salamanders were held （refrigerated） for 7 days before sampling, we cannot be certain if this effect is a stress reaction to the captivity or the normal level for this morph. However comparison with two sets of related salamanders that were captured and sampled immediately indicates the red-stripe salamanders were either not stressed from the captivity at all, or their white blood cell distributions had returned to normal after 7 days of captivity. Taken together, our results indicate that lead-phase forms of P. cinereus have higher stress levels than the red-stripe forms, which may be a consequence of their higher exposure to, and/or attacks from, predators. They may also indicate that the lead-phase form is less-suited to captivity than the red-stripe form of this species.展开更多
Previous work found that different Japanese lineages of salamanders had quite different levels of species and genetic diversity. Lineages vary from having one to several species and the extent of genetic variation amo...Previous work found that different Japanese lineages of salamanders had quite different levels of species and genetic diversity. Lineages vary from having one to several species and the extent of genetic variation among lineages differs substantially. Most speciose,genus Hynobius contains 18 species and several potential cryptic species. We explore genetic diversity in this genus by combining comprehensive sampling and mitochondrial DNA sequences. Based on this and previous analyses of salamanders,relative times of divergence are employed to evaluate the relationship between age and diversity among the four major lineages whose distributions broadly overlap on the islands. For Hynobius,our analyses are congruent with the previously reported high level of cryptic diversity in morphology and allozymes,particularly in species composed of non-sister matrilines. Both species and genetic diversity correlate with the relative ages of the lineages. This correlation indicates that the variation in levels of diversity can be explained,to a considerable extent,by the hypothesis that older insular lineages have accumulated greater diversity. In addition to the Korean Peninsula,H. leechii might have survived in another Pleistocene glacial refugium north of the peninsula and this refugium provided a source of colonization after the last glacial maximum.展开更多
Type 2 diabetes(T2D)presents a significant health challenge,underscoring the need for functional foods and nutraceutical hypoglycemic bioactive peptides for its prevention.This study investigates the potential of prot...Type 2 diabetes(T2D)presents a significant health challenge,underscoring the need for functional foods and nutraceutical hypoglycemic bioactive peptides for its prevention.This study investigates the potential of proteolytic hydrolysate from artificially cultivated Chinese giant salamander(CGS)meat,a rich protein source,as a preventive strategy for T2D.We produced a CGS meat hydrolysate(CGSh)and demonstrated its ability to inhibit the T2D drug target dipeptidyl peptidaseⅣ(DPP-Ⅳ)through in vitro assays.We identified 5 peptides(WRPPDH,WAPPSKD,IPDSPF,IPEMIF,and VPIAVPT)with high DPP-Ⅳinhibitory activity in CGSh,suggesting its potential antidiabetic effects.In vivo experiments showed that CGSh effectively reduced insulin resistance in mice induced with a high-fat diet,as evidenced by a slower increase in blood glucose levels and a decreased HOMA-IR index.16S rRNA sequencing analysis revealed that CGSh improved gut microbial homeostasis,promoting beneficial microorganisms and reducing harmful bacteria.Metabolomic analyses identified an increase in valeric acid levels and highlighted nine potential biomarker metabolites.By inhibiting metabolic pathways such as AGE-RAGE,CGSh might also prevent diabetic complications and reduce inflammation.These findings suggest that CGSh has a promising hypoglycemic effect,making it a potential functional food ingredient for T2D prevention and treatment.展开更多
The Mediterranean region possesses a rich diversity of salamanders,which also exhibit a high degree of ecological diversification.It is assumed that the presence of salamanders is dependent on the level of vegetation ...The Mediterranean region possesses a rich diversity of salamanders,which also exhibit a high degree of ecological diversification.It is assumed that the presence of salamanders is dependent on the level of vegetation cover in terrestrial habitats,but the strength of this association is likely to vary among species.In this study,we investigated the patterns of habitat utilization for Mediterranean salamanders based on 589 records of 33 species.We tested the hypothesis that the association between salamander presence and vegetation density varies among genera or reproductive modes(i.e.terrestrial vs aquatic).The results show that vegetation cover has similar influences on terrestrial and aquatic groups but important differences are identified for lotic and lentic aquatic species.Our findings also indicate that the aquatic lotic,terrestrial,and small-body species deviate significantly from that expected from the background range of variation.展开更多
Andrias davidianus(Chinese giant salamander,CGS)is the largest and oldest extant amphibian species in the world and is a source of prospective functional food in China.However,the progress of functional peptides minin...Andrias davidianus(Chinese giant salamander,CGS)is the largest and oldest extant amphibian species in the world and is a source of prospective functional food in China.However,the progress of functional peptides mining was slow due to lack of reference genome and protein sequence data.In this study,we illustrated full-length transcriptome sequencing to interpret the proteome of CGS meat and obtain 10703 coding DNA sequences.By functional annotation and amino acid composition analysis,we have discovered various genes related to signal transduction,and 16 genes related to longevity.We have also found vast variety of functional peptides through protein coding sequence(CDS)analysis by comparing the data obtained with the functional peptide database.Val-Pro-Ile predicted by the CDS analysis was released from the CGS meat through enzymatic hydrolysis,suggesting that our approach is reliable.This study suggested that transcriptomic analysis can be used as a reference to guide polypeptide mining in CGS meat,thereby providing a powerful mining strategy for the bioresources with unknown genomic and proteomic sequences.展开更多
Objective In order to probe into the morphological and histological characteristics of the telencephalon of Onychodactylusfischeri, and to enrich the comparable neurobiology. Method HE-staining method was used to desc...Objective In order to probe into the morphological and histological characteristics of the telencephalon of Onychodactylusfischeri, and to enrich the comparable neurobiology. Method HE-staining method was used to describe the characters of the telencephalon of Onychodactylus fischeri. Results The olfactory bulb of Onychodactylus fischeri locates in the rastral and lateral to the cerebral hemisphere, and six distinct layers can be identified from the lateral to the medial, quite similar to Batrachuperus tibetanus and Hynobius leechii. In the cerebrum, the primordial hippocampus developed better than the primordial piriform. The former belongs to archipallium and the latter is paleopallium. Ventral to the primordial hippocampus there is a septal area which cannot be divided into medial and lateral parts. In the ventrical wall, there is neither medial limiting sulcus nor lateral limiting sulcus to saperate the primordial hippocampus and the septal area, or the primordial piriform and the corpus striatum. The corpus striatum of Onychodactylusfischeri is paleostriatum. There is choroids plexus anterior in the lateral ventricle. The cell group that located at two sides of the third ventricle is the amygdale. Besides, the shape and size of neurons within the telencephalon are poorly differentiated. Conclusion Onychodactylusfischeri is a relatively primitive type in the amphibian. The present data will help us to further understand the nerve system of tailed amphibian.展开更多
A phylogenetic hypothesis for the Asian newts of the Tylototriton asperrimus group was generated using data from two mitochondrial fragments including COI and the ND1-ND2 regions. Four distinct clades （A, B, C, D） w...A phylogenetic hypothesis for the Asian newts of the Tylototriton asperrimus group was generated using data from two mitochondrial fragments including COI and the ND1-ND2 regions. Four distinct clades （A, B, C, D） were resolved with high nodal support within this monophyletic group. Clade A included T. asperrimus, T. hainanensis, T. notialis, ＂T. vietnamensis＂, and two unnamed salamander populations from Vietnam. Clade A, constituted the sister group of clades B ＋ C. Newly identified clade C likely represents a new cryptic species. Clade C was the sister group of T. wenxianensis. The true 7： vietnamensis exclusively constituted clade D. Our results bring into question some previous taxonomic decisions, and a revision is required. This study illustrates the necessity to include samples from type localities in taxonomic studies, and highlights the importance of fine-grained geographical sampling.展开更多
This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slo...This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slopes are weathered to the same degree and have the same vegetation coverage, slope orientation (azimuthal) is not critical for slope stability. However, it is found that for the region south of the Black Mountains (North Carolina), north-facing slopes are more prone to slide, because, for the regions not limited by water availability (annual precipitation), the northern slopes usually are grass slopes. For the slopes of the Blue Ridge Mountains, south facing slopes are more prone to slide. Gravity measurements over the past decade reveal that geological conditions, the chute system and underground cracks over the region are stable. Future changes in storm-triggered landslide frequency are primarily controlled by changes in extreme precipitation. Thus, a series of ensemble climate model experiments is carried out to investigate possible changes in future extreme precipitation events, using a weather model forced by atmospheric perturbations from ensemble climate models. Over 50 locations are identified as prone to future landslides. Many of these locales are natural habitats to the Appalachian salamanders. In a future warmer climate, more severe extreme precipitation events are projected because of increased atmospheric water vapor and more frequent passages of tropical cyclone remnants. There is also a likely shift of tropical cyclone tracks and associated extreme precipitations, and the cluster center of Appalachians’s scarps is expected to move westward, with ecological consequences for the endemic salamanders.展开更多
This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slo...This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slopes are weathered to the same degree and have the same vegetation coverage, slope orientation (azimuthal) is not critical for slope stability. However, it is found that for the region south of the Black Mountains (North Carolina), north-facing slopes are more prone to slide, because, for the regions not limited by water availability (annual precipitation), the northern slopes usually are grass slopes. For the slopes of the Blue Ridge Mountains, south facing slopes are more prone to slide. Gravity measurements over the past decade reveal that geological conditions, the chute system and underground cracks over the region are stable. Future changes in storm-triggered landslide frequency are primarily controlled by changes in extreme precipitation. Thus, a series of ensemble climate model experiments is carried out to investigate possible changes in future extreme precipitation events, using a weather model forced by atmospheric perturbations from ensemble climate models. Over 50 locations are identified as prone to future landslides. Many of these locales are natural habitats to the Appalachian salamanders. In a future warmer climate, more severe extreme precipitation events are projected because of increased atmospheric water vapor and more frequent passages of tropical cyclone remnants. There is also a likely shift of tropical cyclone tracks and associated extreme precipitations, and the cluster center of Appalachians’s scarps is expected to move westward, with ecological consequences for the endemic salamanders.展开更多
Andrias davidianus,i.e.Chinese giant salamander(CGS),is one of the largest and oldest amphibians existing in the world and is also one of the valuable biological resources of China.Wild CGS has been threatened with ex...Andrias davidianus,i.e.Chinese giant salamander(CGS),is one of the largest and oldest amphibians existing in the world and is also one of the valuable biological resources of China.Wild CGS has been threatened with extinction in the past decades due to over capturing,deterioration of natural environment,the slow breeding and growth of the wild species in nature.However,in the past twenty years,with the breakthrough and progress of artificial breeding technology by artificial insemination,the number of artificially cultivated CGS has increased rapidly.Artificially cultivated CGS can either be released to the CGS living environment to increase the population in nature or legally applied in food and medicinal industry as a feedstock due to the unique nutritional and medicinal values of CGS as recorded historically.In this review,the nutritional components,bioactive components and medicinal activities of the artificially cultivated CGS will be summarized.The mucus,skin,meat and bone of CGS contain many different bioactive substances thereby having various medicinal activities including anti-aging,anti-fatigue,anti-tumor,therapy of burn and anti-infection and other physiological functions.This paper will further discuss the potential applications of the artificially cultivated CGS in healthcare industry and prospects of future technological development.展开更多
Biodiversity is declining globally by an unprecedented extinction rate.This is especially true for amphibians,accounting for 24.3%of all threatened vertebrates.As the largest extant amphibian species in the world,wild...Biodiversity is declining globally by an unprecedented extinction rate.This is especially true for amphibians,accounting for 24.3%of all threatened vertebrates.As the largest extant amphibian species in the world,wild populations of the Chinese giant salamander(Genus Andrias)(CGS)have decreased dramatically because of overexploitation and habitat degradation.Translocation has become an important strategy for restoring threatened wild populations worldwide.However,disordered tra nsloca tion usually has negative effects on the native populations.We provide an overview of CGS translocation and show that disordered translocation can increase local population extinction.Nearly four times the estimated number of wild individuals have been released across China.There a re three types of translocation used for CGS,namely,reinforcement,reintroduction and ecological replacement,the last of which accounts for over one-third of translocations.Our genetic screening revealed that most released individuals were not from local populations,with one to four lineages detected in every release site(n=6).This disordered translocation can potentially reduce the genetic integrity of original populations.Hence,we suggest suspending current CGS translocation activities immediately,until more robust measures can be developed and implemented to improve the current translocation program,especially with respect to lineage identifica tion a nd the identifica tion of appropriate release sites.展开更多
Loop-mediated isothermal ampliifcation （LAMP） is a novel nucleic acid diagnostic method that can amplify rapidly a target template under isothermal conditions. In this study, a LAMP assay for rapid detection of Chin...Loop-mediated isothermal ampliifcation （LAMP） is a novel nucleic acid diagnostic method that can amplify rapidly a target template under isothermal conditions. In this study, a LAMP assay for rapid detection of Chinese giant salamander ranavirus（CGSRV） was developed from culture isolates and clinical samples. The LAMP assay was developed by designing one set of four speciifc primers, targeting the major capsid protein （MCP） gene of CGSRV. Reaction time and temperature were optimal for 40 min at 62°C. The developed LAMP assay is speciifc and highly sensitive for CGSRV detection, the detection limit could reach about 5 copies of cloned viral genomic fragments. The sensitivity of the LAMP assay was about 1000 and 10-fold higher than that of both conventional and nested PCR, respectively. The LAMP ampliifcation produces a typical ladder-like pattern of products on an agarose gel that can be visually inspected after addition of ethidium bromide. The LAMP assay was evaluated further with clinical samples, and the results indicated the suitability and simplicity of the test as a rapid diagnostic tool for the detection of CGSRV.展开更多
Morganella morganii strain 602-1 was isolated from a sick Chinese giant salamander （Andrias davidianus）. The strain 602-1 was identified through its physiological and biochemical properties and 16S rDNA gene amplifi...Morganella morganii strain 602-1 was isolated from a sick Chinese giant salamander （Andrias davidianus）. The strain 602-1 was identified through its physiological and biochemical properties and 16S rDNA gene amplification and analyses. Pathogenicity was proven by experimental animal infection, and histopathological examination. The results showed that the amplified 16S rDNA sequence of strain 602-1 was 1455 bp, and showed 99% identity with M. morganii. In the host infection experiment, the mortality of Chinese giant salamanders was about 70%. Pathological changes occurred in the spleen, heart, liver, kidney and intestine. This study will help the prevention, understanding and cure for M. morganii infections in amphibians.展开更多
As a group of intestinal hormones and neurotransmitters, cholecystokinins（CCKs） regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally...As a group of intestinal hormones and neurotransmitters, cholecystokinins（CCKs） regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally contain a DYMGWMDFG sequence at the C-terminus. Many CCKs have been reported in mammals. However, only a few have been reported in amphibians, such as Hyla nigrovittata, Xenopus laevis, and Rana catesbeiana, with none reported in urodele amphibians like newts and salamanders. Here, a CCK called CCK-TV was identified and characterized from the skin of the salamander Tylototriton verrucosus. This CCK contained an amino acid sequence of DYMGWMDF-NH2 as seen in other CCKs. A c DNA encoding the CCK precursor containing 129 amino acid residues was cloned from the c DNA library of T. verrucosus skin. The CCK-TV had the potential to induce the contraction of smooth muscle strips isolated from porcine gallbladder, eliciting contraction at a concentration of 5.0x10-11 mol/L and inducing maximal contraction at a concentration of 2.0x10-6 mol/L. The EC50 was 13.6 nmol/L. To the best of our knowledge, this is the first report to identify the presence of a CCK in an urodele amphibian.展开更多
Due to the overexploitation of farming,as well as habitat destruction,the wild population of Chinese giant salamander(CGS)Andrias davidianus,a species with seven genetically distinct lineages,has decreased by over 80%...Due to the overexploitation of farming,as well as habitat destruction,the wild population of Chinese giant salamander(CGS)Andrias davidianus,a species with seven genetically distinct lineages,has decreased by over 80%in the past 70 years.Traditional survey methods have proven to be unsuitable for finding this rare and elusive species.We evaluated the efficacy of environmental DNA(eDNA)sampling to detect CGS indirectly from its aquatic environment.We developed several species-specific primer sets;validated their specificity and sensitivity;and assessed their utility in silico,in the laboratory,and at two field sites harboring released farm-bred CGS.We detected the presence of CGS DNA by using polymerase chain reaction and Sanger sequencing.We also sequenced an amplicon mixture of seven haplotype-represented samples using high-throughput sequencing.Our eDNA methods could detect the presence of CGS at moderate densities reported across its range,proving them as a cost-effective way to establish broad-scale patterns of occupancy for CGS.In addition,our primers enabled the detection of mitochondrial lineage mixture or introduced individuals from geographically isolated populations of CGS.展开更多
The chromosomal localization of 45S ribosomal RNA genes in Ambystoma jeffersonianum was determined by fluorescence in situ hybridization with 18S rDNA fragment as a probe (FISH-rDNA). Our results revealed the presence...The chromosomal localization of 45S ribosomal RNA genes in Ambystoma jeffersonianum was determined by fluorescence in situ hybridization with 18S rDNA fragment as a probe (FISH-rDNA). Our results revealed the presence of rDNA polymorphism among A.jeffersonianum populations in terms of number,location and FISH signal intensity on the chromosomes. Nine rDNA cytotypes were found in ten geographically isolated populations and most of them contained derivative rDNA sites. Our preliminary study provides strong indication of karyotypic diversification of A.jeffersonianum that is demonstrated by intraspecific variation of 45S rDNA cytotypes. rDNA cytotype polymorphism has been described in many other caudate amphibians. We predict that habitat isolation,low dispersal ability and decline of effective population size could facilitate the fixation and accumulation of variable rDNA cytotypes during their chromosome evolution.展开更多
文摘We investigated how exposure duration （time that two individuals initially interact） and separation interval （time be- tween the initial interaction and a subsequent interaction） affect recognition memory of conspecifics in male red-backed sala- manders Plethodon cinereus. Previous studies have demonstrated that this species aggressively defends territories. We recorded aggressive behavior to assess recognition memory, because aggression is more intense toward previously unencountered indi- viduals compared to previously encountered individuals in this species. We found that with 15-min exposures and 5-day separa- tion intervals, focal males did not spend significantly more time threatening ＇unfamiliar＇ intruders than ＇familiar＇ intruders. After either 8-hour exposures and 5-day separation intervals and 5-day exposures and 5-day separation intervals, focal males spent sig- nificantly more time threatening unfamiliar intruders than familiar intruders. These results suggest that male red-backed salaman- ders can remember familiar conspecifics （e.g., territorial neighbors） after at least an 8-hour exposure duration and that memory persists at least as long as 5 days. After 5-day exposure and 15-day separation intervals, we found no significant difference in ag- gressive behavior toward familiar and unfamiliar intruders. Long separation intervals （15 days） may lead either to loss of memory of previously familiar individuals or, alternatively, aggressive reassessment of individuals as only a change in behavior indicates positively that memory has occurred. Thus, variance in territorial defense within an individual may depend on its ability to recog- nize conspecific males .
文摘Currently nine families of tailed amphibians, including 682 species, are recognised in the world. Five of these families, including some 166 species, occur in the Old World （Europe, Asia, and Northern Africa）. The family of hynobiid salamanders （hynobiidae） is endemic to this region, whereas the other families also are represented in the New World （America）. Salamanders of the Old Worm is a comprehensive monograph authored by Max Sparreboom. With this book, which aims to be an up- date of Robert Thorn＇s book of 1969, the author presents updated information on salamander species diversity in this region. The book is bound to become a classic in its field： it contains descriptions of all five families and 166 salamander species, a taxonomical diagnosis, distribution maps, and a wealth of information on habitat preferences, behaviour, threats, conservation, etc. Every species chapter is followed by a comment by the author and references to technical literature. For many species the biological information comes from the author himself, who made observations of behaviour in aquariums and in the field. This knowledge is supplemented with information from the scientific literature, which is synthesized in a systematic way. What will especially appeal to the reader is the great number of beautiful pictures in the text, showing details of morphological characters, habitat and bebaviour in the different life history stages. These features add to the value of the book, both in scientific and artistic aspects.
基金This study was supported by the National Natural Science Foundation of China(31771617)and HZAU-AGIS Cooperation Fund(SZYJY2021009)。
文摘Salamanders are unique among tetrapods in their ability to regenerate the limbs throughout life.Like other poikilothermic amphibians,salamanders also show a remarkable capacity to survive long periods of starvation.Whether the physiological reserves necessary for tissue regeneration are preserved or sacrificed in starved salamanders is unknown.In the current study,we maintained Iberian ribbed newts(Pleurodeles waltl)under extreme physiological stress to assess the extent of regeneration and identify the molecular and cellular changes that may occur under such conditions.After 19 months of complete food deprivation,the animals exhibited extensive morphological and physiological adaptations but remained behaviorally active and vigilant.Autophagy was elevated in different tissues and the transformed gut microbiota indicated remodeling of the intestinal tract related to autophagy.Upon limb amputation in animals starved for 21 months,regeneration proceeded with progenitor cell proliferation and migration,leading to limb blastema formation.However,limb outgrowth and patterning were substantially attenuated.Blockage of autophagy inhibited cell proliferation and blastema formation in starved animals,but not in fed animals.Hence,tissue autophagy and the regenerative response were tightly coupled only when animals were under stress.Our results demonstrate that under adverse conditions,salamanders can exploit alternative strategies to secure blastema formation for limb regeneration.
基金Funding for AKD during this project was provided by the DBWarnell School of Forestry and Natural Resources and a grant from the Morris Animal FoundationSupport for the field word of this project came form an NSF grant (NSF-DEB DEB0542974)
文摘Throughout the animal kingdom there are species that have two or more phenotypic forms or ‘morphs＇, and many of these are amphibians. In North America, the red-backed salamander Plethodon cinereus can have either a red dorsal stripe or no dorsal stripe （lead-phase form）, and evidence to date indicates the lead-phase form incurs a greater number of attacks from predators. In a recent collection of 51 P cinereus, blood smears of both color morphs （35 red-stripe, 16 lead-phase） were examined to obtain numbers of circulating leukocytes （via light microscopy）, which can be used to indirectly estimate levels of stress hormones in vertebrates via a ‘hematological stress index＇, which is the ratio between the number of two leukocyte types （neutrophils and lymphocytes）. Our results showed that lead-phase salamanders tended to have greater numbers of circulating neutrophils and lower numbers of circulating lymphocytes than red-stripe morphs, leading to higher average neutrophil-lymphocyte ratios in lead-phase individuals. Since the salamanders were held （refrigerated） for 7 days before sampling, we cannot be certain if this effect is a stress reaction to the captivity or the normal level for this morph. However comparison with two sets of related salamanders that were captured and sampled immediately indicates the red-stripe salamanders were either not stressed from the captivity at all, or their white blood cell distributions had returned to normal after 7 days of captivity. Taken together, our results indicate that lead-phase forms of P. cinereus have higher stress levels than the red-stripe forms, which may be a consequence of their higher exposure to, and/or attacks from, predators. They may also indicate that the lead-phase form is less-suited to captivity than the red-stripe form of this species.
基金supported by the Chinese Academy of Sciences (09C3011100, KSCX2- YW-Z-0906, KSCX2-EW-J-22)the National Natural Science Foundation of China (NSFC-30870287, NSFC-30900134)the Natural Sciences and Engineering Research Council (Canada) Discovery Grant 3148
文摘Previous work found that different Japanese lineages of salamanders had quite different levels of species and genetic diversity. Lineages vary from having one to several species and the extent of genetic variation among lineages differs substantially. Most speciose,genus Hynobius contains 18 species and several potential cryptic species. We explore genetic diversity in this genus by combining comprehensive sampling and mitochondrial DNA sequences. Based on this and previous analyses of salamanders,relative times of divergence are employed to evaluate the relationship between age and diversity among the four major lineages whose distributions broadly overlap on the islands. For Hynobius,our analyses are congruent with the previously reported high level of cryptic diversity in morphology and allozymes,particularly in species composed of non-sister matrilines. Both species and genetic diversity correlate with the relative ages of the lineages. This correlation indicates that the variation in levels of diversity can be explained,to a considerable extent,by the hypothesis that older insular lineages have accumulated greater diversity. In addition to the Korean Peninsula,H. leechii might have survived in another Pleistocene glacial refugium north of the peninsula and this refugium provided a source of colonization after the last glacial maximum.
基金funded by the Shenzhen Agricultural Development Special Fund(Fishery)Agricultural High-tech Project([2021]735)SAMR technical guarantee project(2023YJ22 and 2023YJ37)。
文摘Type 2 diabetes(T2D)presents a significant health challenge,underscoring the need for functional foods and nutraceutical hypoglycemic bioactive peptides for its prevention.This study investigates the potential of proteolytic hydrolysate from artificially cultivated Chinese giant salamander(CGS)meat,a rich protein source,as a preventive strategy for T2D.We produced a CGS meat hydrolysate(CGSh)and demonstrated its ability to inhibit the T2D drug target dipeptidyl peptidaseⅣ(DPP-Ⅳ)through in vitro assays.We identified 5 peptides(WRPPDH,WAPPSKD,IPDSPF,IPEMIF,and VPIAVPT)with high DPP-Ⅳinhibitory activity in CGSh,suggesting its potential antidiabetic effects.In vivo experiments showed that CGSh effectively reduced insulin resistance in mice induced with a high-fat diet,as evidenced by a slower increase in blood glucose levels and a decreased HOMA-IR index.16S rRNA sequencing analysis revealed that CGSh improved gut microbial homeostasis,promoting beneficial microorganisms and reducing harmful bacteria.Metabolomic analyses identified an increase in valeric acid levels and highlighted nine potential biomarker metabolites.By inhibiting metabolic pathways such as AGE-RAGE,CGSh might also prevent diabetic complications and reduce inflammation.These findings suggest that CGSh has a promising hypoglycemic effect,making it a potential functional food ingredient for T2D prevention and treatment.
文摘The Mediterranean region possesses a rich diversity of salamanders,which also exhibit a high degree of ecological diversification.It is assumed that the presence of salamanders is dependent on the level of vegetation cover in terrestrial habitats,but the strength of this association is likely to vary among species.In this study,we investigated the patterns of habitat utilization for Mediterranean salamanders based on 589 records of 33 species.We tested the hypothesis that the association between salamander presence and vegetation density varies among genera or reproductive modes(i.e.terrestrial vs aquatic).The results show that vegetation cover has similar influences on terrestrial and aquatic groups but important differences are identified for lotic and lentic aquatic species.Our findings also indicate that the aquatic lotic,terrestrial,and small-body species deviate significantly from that expected from the background range of variation.
基金funded by Shenzhen Science and Technology Innovation Commission(KCXFZ20201221173207022)。
文摘Andrias davidianus(Chinese giant salamander,CGS)is the largest and oldest extant amphibian species in the world and is a source of prospective functional food in China.However,the progress of functional peptides mining was slow due to lack of reference genome and protein sequence data.In this study,we illustrated full-length transcriptome sequencing to interpret the proteome of CGS meat and obtain 10703 coding DNA sequences.By functional annotation and amino acid composition analysis,we have discovered various genes related to signal transduction,and 16 genes related to longevity.We have also found vast variety of functional peptides through protein coding sequence(CDS)analysis by comparing the data obtained with the functional peptide database.Val-Pro-Ile predicted by the CDS analysis was released from the CGS meat through enzymatic hydrolysis,suggesting that our approach is reliable.This study suggested that transcriptomic analysis can be used as a reference to guide polypeptide mining in CGS meat,thereby providing a powerful mining strategy for the bioresources with unknown genomic and proteomic sequences.
文摘Objective In order to probe into the morphological and histological characteristics of the telencephalon of Onychodactylusfischeri, and to enrich the comparable neurobiology. Method HE-staining method was used to describe the characters of the telencephalon of Onychodactylus fischeri. Results The olfactory bulb of Onychodactylus fischeri locates in the rastral and lateral to the cerebral hemisphere, and six distinct layers can be identified from the lateral to the medial, quite similar to Batrachuperus tibetanus and Hynobius leechii. In the cerebrum, the primordial hippocampus developed better than the primordial piriform. The former belongs to archipallium and the latter is paleopallium. Ventral to the primordial hippocampus there is a septal area which cannot be divided into medial and lateral parts. In the ventrical wall, there is neither medial limiting sulcus nor lateral limiting sulcus to saperate the primordial hippocampus and the septal area, or the primordial piriform and the corpus striatum. The corpus striatum of Onychodactylusfischeri is paleostriatum. There is choroids plexus anterior in the lateral ventricle. The cell group that located at two sides of the third ventricle is the amygdale. Besides, the shape and size of neurons within the telencephalon are poorly differentiated. Conclusion Onychodactylusfischeri is a relatively primitive type in the amphibian. The present data will help us to further understand the nerve system of tailed amphibian.
基金supported by grants from the Ministry of Science and Technology of China(MOST Grant 2011FY120200)the National Natural Science Foundation of China(31090100,30870281)+1 种基金the Chinese Academy of Sciences(KSCX2-YW-Z-0807,KSCX2-EW-Z-2)the Bureau of Science and Technology of Yunnan province
文摘A phylogenetic hypothesis for the Asian newts of the Tylototriton asperrimus group was generated using data from two mitochondrial fragments including COI and the ND1-ND2 regions. Four distinct clades （A, B, C, D） were resolved with high nodal support within this monophyletic group. Clade A included T. asperrimus, T. hainanensis, T. notialis, ＂T. vietnamensis＂, and two unnamed salamander populations from Vietnam. Clade A, constituted the sister group of clades B ＋ C. Newly identified clade C likely represents a new cryptic species. Clade C was the sister group of T. wenxianensis. The true 7： vietnamensis exclusively constituted clade D. Our results bring into question some previous taxonomic decisions, and a revision is required. This study illustrates the necessity to include samples from type localities in taxonomic studies, and highlights the importance of fine-grained geographical sampling.
文摘This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slopes are weathered to the same degree and have the same vegetation coverage, slope orientation (azimuthal) is not critical for slope stability. However, it is found that for the region south of the Black Mountains (North Carolina), north-facing slopes are more prone to slide, because, for the regions not limited by water availability (annual precipitation), the northern slopes usually are grass slopes. For the slopes of the Blue Ridge Mountains, south facing slopes are more prone to slide. Gravity measurements over the past decade reveal that geological conditions, the chute system and underground cracks over the region are stable. Future changes in storm-triggered landslide frequency are primarily controlled by changes in extreme precipitation. Thus, a series of ensemble climate model experiments is carried out to investigate possible changes in future extreme precipitation events, using a weather model forced by atmospheric perturbations from ensemble climate models. Over 50 locations are identified as prone to future landslides. Many of these locales are natural habitats to the Appalachian salamanders. In a future warmer climate, more severe extreme precipitation events are projected because of increased atmospheric water vapor and more frequent passages of tropical cyclone remnants. There is also a likely shift of tropical cyclone tracks and associated extreme precipitations, and the cluster center of Appalachians’s scarps is expected to move westward, with ecological consequences for the endemic salamanders.
文摘This study analyzes storm-triggered landslides in the US Appalachians, in the current geological setting. Concave valleys that favor the convergence of surface runoff are the primary locales for landslides. If the slopes are weathered to the same degree and have the same vegetation coverage, slope orientation (azimuthal) is not critical for slope stability. However, it is found that for the region south of the Black Mountains (North Carolina), north-facing slopes are more prone to slide, because, for the regions not limited by water availability (annual precipitation), the northern slopes usually are grass slopes. For the slopes of the Blue Ridge Mountains, south facing slopes are more prone to slide. Gravity measurements over the past decade reveal that geological conditions, the chute system and underground cracks over the region are stable. Future changes in storm-triggered landslide frequency are primarily controlled by changes in extreme precipitation. Thus, a series of ensemble climate model experiments is carried out to investigate possible changes in future extreme precipitation events, using a weather model forced by atmospheric perturbations from ensemble climate models. Over 50 locations are identified as prone to future landslides. Many of these locales are natural habitats to the Appalachian salamanders. In a future warmer climate, more severe extreme precipitation events are projected because of increased atmospheric water vapor and more frequent passages of tropical cyclone remnants. There is also a likely shift of tropical cyclone tracks and associated extreme precipitations, and the cluster center of Appalachians’s scarps is expected to move westward, with ecological consequences for the endemic salamanders.
基金The authors would like to thank the National Key R&D Plan of China for providing support(NO:2016YFD0400203-4).
文摘Andrias davidianus,i.e.Chinese giant salamander(CGS),is one of the largest and oldest amphibians existing in the world and is also one of the valuable biological resources of China.Wild CGS has been threatened with extinction in the past decades due to over capturing,deterioration of natural environment,the slow breeding and growth of the wild species in nature.However,in the past twenty years,with the breakthrough and progress of artificial breeding technology by artificial insemination,the number of artificially cultivated CGS has increased rapidly.Artificially cultivated CGS can either be released to the CGS living environment to increase the population in nature or legally applied in food and medicinal industry as a feedstock due to the unique nutritional and medicinal values of CGS as recorded historically.In this review,the nutritional components,bioactive components and medicinal activities of the artificially cultivated CGS will be summarized.The mucus,skin,meat and bone of CGS contain many different bioactive substances thereby having various medicinal activities including anti-aging,anti-fatigue,anti-tumor,therapy of burn and anti-infection and other physiological functions.This paper will further discuss the potential applications of the artificially cultivated CGS in healthcare industry and prospects of future technological development.
基金supported by the National Key Programme of Research and Development,Ministry of Science and Technology(2016YFC0503200)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23080101)+3 种基金the Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment,China(2019HJ2096001006)the Open Project of CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization&Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province(KXYSWS2006)the Construction of Basic Conditions Platform of Sichuan Science and Technology Department(2019JDPT0020)China Biodiversity Observa tion Networks(Sino BON)。
文摘Biodiversity is declining globally by an unprecedented extinction rate.This is especially true for amphibians,accounting for 24.3%of all threatened vertebrates.As the largest extant amphibian species in the world,wild populations of the Chinese giant salamander(Genus Andrias)(CGS)have decreased dramatically because of overexploitation and habitat degradation.Translocation has become an important strategy for restoring threatened wild populations worldwide.However,disordered tra nsloca tion usually has negative effects on the native populations.We provide an overview of CGS translocation and show that disordered translocation can increase local population extinction.Nearly four times the estimated number of wild individuals have been released across China.There a re three types of translocation used for CGS,namely,reinforcement,reintroduction and ecological replacement,the last of which accounts for over one-third of translocations.Our genetic screening revealed that most released individuals were not from local populations,with one to four lineages detected in every release site(n=6).This disordered translocation can potentially reduce the genetic integrity of original populations.Hence,we suggest suspending current CGS translocation activities immediately,until more robust measures can be developed and implemented to improve the current translocation program,especially with respect to lineage identifica tion a nd the identifica tion of appropriate release sites.
基金supported by the Sichuan Technology Support Planning (No. 2014 NZ0027)
文摘Loop-mediated isothermal ampliifcation （LAMP） is a novel nucleic acid diagnostic method that can amplify rapidly a target template under isothermal conditions. In this study, a LAMP assay for rapid detection of Chinese giant salamander ranavirus（CGSRV） was developed from culture isolates and clinical samples. The LAMP assay was developed by designing one set of four speciifc primers, targeting the major capsid protein （MCP） gene of CGSRV. Reaction time and temperature were optimal for 40 min at 62°C. The developed LAMP assay is speciifc and highly sensitive for CGSRV detection, the detection limit could reach about 5 copies of cloned viral genomic fragments. The sensitivity of the LAMP assay was about 1000 and 10-fold higher than that of both conventional and nested PCR, respectively. The LAMP ampliifcation produces a typical ladder-like pattern of products on an agarose gel that can be visually inspected after addition of ethidium bromide. The LAMP assay was evaluated further with clinical samples, and the results indicated the suitability and simplicity of the test as a rapid diagnostic tool for the detection of CGSRV.
基金supported by the research grants from Science and Technology Department of Sichuan (2013FZ0014)Construction Project of Postgraduate Academic Degree in Southwest University for Nationalities (2013XWD–S071007)
文摘Morganella morganii strain 602-1 was isolated from a sick Chinese giant salamander （Andrias davidianus）. The strain 602-1 was identified through its physiological and biochemical properties and 16S rDNA gene amplification and analyses. Pathogenicity was proven by experimental animal infection, and histopathological examination. The results showed that the amplified 16S rDNA sequence of strain 602-1 was 1455 bp, and showed 99% identity with M. morganii. In the host infection experiment, the mortality of Chinese giant salamanders was about 70%. Pathological changes occurred in the spleen, heart, liver, kidney and intestine. This study will help the prevention, understanding and cure for M. morganii infections in amphibians.
基金supported by the National Basic Research Program of China（973 Program）（2013CB911300）National Natural Science Foundation of China（U1132601）the Chinese Academy of Sciences（SAJC201308）
文摘As a group of intestinal hormones and neurotransmitters, cholecystokinins（CCKs） regulate and affect pancreatic enzyme secretion, gastrointestinal motility, pain hypersensitivity, digestion and satiety, and generally contain a DYMGWMDFG sequence at the C-terminus. Many CCKs have been reported in mammals. However, only a few have been reported in amphibians, such as Hyla nigrovittata, Xenopus laevis, and Rana catesbeiana, with none reported in urodele amphibians like newts and salamanders. Here, a CCK called CCK-TV was identified and characterized from the skin of the salamander Tylototriton verrucosus. This CCK contained an amino acid sequence of DYMGWMDF-NH2 as seen in other CCKs. A c DNA encoding the CCK precursor containing 129 amino acid residues was cloned from the c DNA library of T. verrucosus skin. The CCK-TV had the potential to induce the contraction of smooth muscle strips isolated from porcine gallbladder, eliciting contraction at a concentration of 5.0x10-11 mol/L and inducing maximal contraction at a concentration of 2.0x10-6 mol/L. The EC50 was 13.6 nmol/L. To the best of our knowledge, this is the first report to identify the presence of a CCK in an urodele amphibian.
基金the National Key Program of Research and Development(2016YFC0503200)the National Natural Science Foundation of China(31570391,31200411)+2 种基金the Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment(2019HJ2096001006)the Construction of Basic Conditions Platform of Sichuan Science and Technology Department(2019JDPT0020)the China Biodiversity Observation Networks(Sino BON-Amphibian&Reptile).
文摘Due to the overexploitation of farming,as well as habitat destruction,the wild population of Chinese giant salamander(CGS)Andrias davidianus,a species with seven genetically distinct lineages,has decreased by over 80%in the past 70 years.Traditional survey methods have proven to be unsuitable for finding this rare and elusive species.We evaluated the efficacy of environmental DNA(eDNA)sampling to detect CGS indirectly from its aquatic environment.We developed several species-specific primer sets;validated their specificity and sensitivity;and assessed their utility in silico,in the laboratory,and at two field sites harboring released farm-bred CGS.We detected the presence of CGS DNA by using polymerase chain reaction and Sanger sequencing.We also sequenced an amplicon mixture of seven haplotype-represented samples using high-throughput sequencing.Our eDNA methods could detect the presence of CGS at moderate densities reported across its range,proving them as a cost-effective way to establish broad-scale patterns of occupancy for CGS.In addition,our primers enabled the detection of mitochondrial lineage mixture or introduced individuals from geographically isolated populations of CGS.
文摘The chromosomal localization of 45S ribosomal RNA genes in Ambystoma jeffersonianum was determined by fluorescence in situ hybridization with 18S rDNA fragment as a probe (FISH-rDNA). Our results revealed the presence of rDNA polymorphism among A.jeffersonianum populations in terms of number,location and FISH signal intensity on the chromosomes. Nine rDNA cytotypes were found in ten geographically isolated populations and most of them contained derivative rDNA sites. Our preliminary study provides strong indication of karyotypic diversification of A.jeffersonianum that is demonstrated by intraspecific variation of 45S rDNA cytotypes. rDNA cytotype polymorphism has been described in many other caudate amphibians. We predict that habitat isolation,low dispersal ability and decline of effective population size could facilitate the fixation and accumulation of variable rDNA cytotypes during their chromosome evolution.
