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
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
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
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
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
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
Hynobius amjiensis is a critically endangered salamander species（IUCN Red List） endemic to eastern China. It currently has three known populations： one in Longwangshan, Zhejiang Province（type locality）, and two i...Hynobius amjiensis is a critically endangered salamander species（IUCN Red List） endemic to eastern China. It currently has three known populations： one in Longwangshan, Zhejiang Province（type locality）, and two in Qingliangfeng between Anhui and Zhejiang Provinces. We examined the relatively unstudied breeding ecology of this species in the field and at laboratory from March 2007 to May 2014. Adult males and females were year-round terrestrial, except for the February–April breeding season. During this period, we captured only a total of 16 breeding adults（11 males and 5 females）. As few as 100 breeding females were estimated based on the number of egg sacs observed since 2007. This number was significantly reduced from the estimated number between 1992 and 1998. Males（mean total length = 16.21 cm, mean body mass = 18.8 g） were slightly smaller than females（16.51 cm, 19.2 g）. Size of breeding pools ranged from 0.2 m-2 to 1.2 m-2（0.1–1.2 m depths）. Each female deposits a pair of egg sacs by attaching the adhesive tips of the sacs to aquatic plants or dead twigs. Fifteen pairs of egg sacs had an average length of 28.6 cm and a diameter of 3.3 cm. On average, each egg sac contained 75 eggs with a diameter of 0.3 cm. Our field survey revealed that H. amjiensis used oviposition sites in small, cool, and weakly acidic pools at high elevations（1 300–1 600 m） where peat moss was abundant. Reduction in wetland size and disappearance of suitable breeding pools suggest that this salamander species is under threat of extinction, particularly at Longwangshan, where 5 of the 9 breeding pools have either dried up or disappeared. Combined size of the remaining 4 pools is less than 2 m-2. We urge immediate implementation of more effective conservation measures and suggest that preservation priority should be given to habitat that contains suitable breeding pools.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
Recovery of locomotor behavior following spinal cord injury can occur spontaneously in some vertebrates, such as fish, urodele amphibians, and certain reptiles. This review provides an overview of the current status o...Recovery of locomotor behavior following spinal cord injury can occur spontaneously in some vertebrates, such as fish, urodele amphibians, and certain reptiles. This review provides an overview of the current status of our knowledge on the anatomical and electrophysiological changes occurring within the spinal cord that lead to, or are associated with the [e-expression of locomotion in spinally-transected salamanders. A better understanding of these processes will help to devise strategies for restoring locomotor function in mammals, including humans.展开更多
The Chinese giant salamander(Andrias davidianus) is the largest living amphibian in the world. Aeromonas hydrophila strain L602 was isolated from A. davidianus. The 16S rDNA gene of this isolate was amplified using PC...The Chinese giant salamander(Andrias davidianus) is the largest living amphibian in the world. Aeromonas hydrophila strain L602 was isolated from A. davidianus. The 16S rDNA gene of this isolate was amplified using PCR,and the phylogenetic tree was constructed by the neighbor-joining method. Four virulence genes(aerA,aha1,hly and alt) of A. hydrophila were amplified by PCR and drug resistances were tested using Kirby-Bauer disk diffusion method. The results showed that the length of this 16S rDNA sequence was 1453 bp,which showed 99% homology with A. hydrophila. The GenBank accession number was JX155398. Phylogenetic analysis indicated it grouped together with A. hydrophila. Four virulence genes were all detected,indicating that strain L602 was highly virulent. This stain was resistant to four antibiotics(vibramycin,furazolidone,ampicillin and erythromycin),while it was insensitive to streptomycin. Furthermore,this strain was susceptible to six antibiotics(sulfafurazole,ciprofloxacin,penbritin,norfloxacin,florfenicol and enrofloxacin). This study will help to validate the classification and virulence of pathogenic bacteria in amphibians.展开更多
13 water quality parameters were tested from 38 reaches of 34 counties in Guizhou where Chinese giant salamander(Andrias davidianus) distributed over the past 30 years. Dissolved oxygen and p H were found to be signif...13 water quality parameters were tested from 38 reaches of 34 counties in Guizhou where Chinese giant salamander(Andrias davidianus) distributed over the past 30 years. Dissolved oxygen and p H were found to be significant determinants of the species distribution in recent years(P<0.05). There was no Chinese giant salamander distribution in the recent five years in rivers with dissolved solids of greater than 415 mg/L, conductivity of greater than 639 us/cm, salinity of greater than 0.31 ppt and total hardness of greater than 150 mg/L. Sensitive to environment, the Chinese giant salamander is an important indicator for environmental quality, so it could be used as one of the environmental indicator. Eutrophication, chemical fertilizer, pesticides and inorganic pollutants may be one of reasons driving wild CGS into extinction.展开更多
Although salamanders have been shown to respond to classical conditioning, spatial learning has been largely unstudied. We tested whether salamanders could learn to locate foraging areas by using landmarks. We trained...Although salamanders have been shown to respond to classical conditioning, spatial learning has been largely unstudied. We tested whether salamanders could learn to locate foraging areas by using landmarks. We trained 10 salamanders Plethodon angusticlavius to use landmarks （small rocks） to locate patches within the arena containing food （blackworms Lumbriculus variegatus）. At the comers of each square testing arena were four plastic dishes, one containing blackworms and the other three empty. A rock was placed in front of the dish containing blackworms, and the location of the food-dish was randomly chosen for each training trial. A control group was also trained to feed on blackworms in the presence of a rock, but the rock was positioned randomly among the four dish locations so that the rock was not a reliable landmark for the worms. Although the length of the training period for individual salamanders varied （22-38 trainings per individual）, the mean number of trainings for salamanders in the control and experimental groups was equal （30 training trials）. During testing, no blackworms were present to eliminate any visual or chemical cues emanating directly from the prey. Individuals trained with the rock landmarks spent sig- nificantly more time in the area of the landmark than did control salamanders [Current Zoology 57 （4）： 485-490, 2011].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
Salamanders have evolved functions of attaching to a variety of surfaces under wet conditions,but racial diversity may cause a difference in attachment behaviors and epidermal characteristics.The sticking and climbing...Salamanders have evolved functions of attaching to a variety of surfaces under wet conditions,but racial diversity may cause a difference in attachment behaviors and epidermal characteristics.The sticking and climbing abilities of the Chinese Fire Belly Newt(CFBN),Chinese Warts Triton(CWT),Spotless Stout Newt(SSN),and Chinese Giant Salamander(CGS)on various surfaces were investigated and compared in terms of epidermal morphology,body size,and wettability.The results indicate that the spotless stout newt has an excellent ability for wet attachment,compared to other salamanders under a certain contact case,resulting from its lower mass/body surface area and more visible epidermal structures.Supplementation with moderate water is beneficial for salamander attachment,and the surface roughness in the flood case also promotes the wet attachment.The CFBN has the most hydrophilic epidermis among the samples,where the water droplet quickly spreads over,presenting a completely wetting case.This study offers a comprehensive understanding of the wet attachments and the epidermal characteristics of salamanders,which is meaningful for the application of bioinspired adhesives.展开更多
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
The diet composition of the Lycian salamander Lyciasalamandra luschani basoglui across both age and sex groups was studied. Specimens were collected from a small island in the Southeast Aegean Sea. The dominant prey g...The diet composition of the Lycian salamander Lyciasalamandra luschani basoglui across both age and sex groups was studied. Specimens were collected from a small island in the Southeast Aegean Sea. The dominant prey group of juveniles consisted of Collembola, while Coleoptera dominated the diet of males and females. The number and size of prey items consumed by males and females of L. luschani basoglui were quite similar, while juveniles ate fewer items of much smaller size. The numerical abundance along with the four measures of the size of prey permitted discrimination among males, females and juveniles. Although discrimination between adults and juveniles is expected due to dissimilarity in body size, discrimination between males and females remains inexplicable despite their similarity in body size. Future studies should be focused on understanding how and why prey choice differs between sexes in L. luschani basoglui.展开更多
Chinese giant salamander(CGS, Andrias davidianus) is experiencing the threat of extinction. It is disappearing gradually, because of overharvesting, environmental pollution, specially river pollution, activity of huma...Chinese giant salamander(CGS, Andrias davidianus) is experiencing the threat of extinction. It is disappearing gradually, because of overharvesting, environmental pollution, specially river pollution, activity of human exploitation, and so on. We conducted community interview fieldworks to collect respondent data from Xieba Country(not reserve) situated in Zhengan County of Guizhou Province, where one of the places known by historical giant salamander records in Guizhou. Through the analysis of the collected data, we created quantitative data of use for conservation management on the local status of salamander populations, and we compared our data with those available data of Y. Pan et al., who investigated the status of CGS in 3 reserves in Guizhou Province in 2015.The conclusions have a similar trend, which proved that the collected data were creditable. Through statistical analysis of the comparison data, the number of wild CGS decreased actually followed the increase of artificial framing.Because of the source of breeding to catch wild CGS, overharvesting was likely the most reason to make wild CGS decline.展开更多
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.
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.
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funded by the Zhejiang Provincial Natural Science Foundation(LQ12C06001)
文摘Hynobius amjiensis is a critically endangered salamander species（IUCN Red List） endemic to eastern China. It currently has three known populations： one in Longwangshan, Zhejiang Province（type locality）, and two in Qingliangfeng between Anhui and Zhejiang Provinces. We examined the relatively unstudied breeding ecology of this species in the field and at laboratory from March 2007 to May 2014. Adult males and females were year-round terrestrial, except for the February–April breeding season. During this period, we captured only a total of 16 breeding adults（11 males and 5 females）. As few as 100 breeding females were estimated based on the number of egg sacs observed since 2007. This number was significantly reduced from the estimated number between 1992 and 1998. Males（mean total length = 16.21 cm, mean body mass = 18.8 g） were slightly smaller than females（16.51 cm, 19.2 g）. Size of breeding pools ranged from 0.2 m-2 to 1.2 m-2（0.1–1.2 m depths）. Each female deposits a pair of egg sacs by attaching the adhesive tips of the sacs to aquatic plants or dead twigs. Fifteen pairs of egg sacs had an average length of 28.6 cm and a diameter of 3.3 cm. On average, each egg sac contained 75 eggs with a diameter of 0.3 cm. Our field survey revealed that H. amjiensis used oviposition sites in small, cool, and weakly acidic pools at high elevations（1 300–1 600 m） where peat moss was abundant. Reduction in wetland size and disappearance of suitable breeding pools suggest that this salamander species is under threat of extinction, particularly at Longwangshan, where 5 of the 9 breeding pools have either dried up or disappeared. Combined size of the remaining 4 pools is less than 2 m-2. We urge immediate implementation of more effective conservation measures and suggest that preservation priority should be given to habitat that contains suitable breeding pools.
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 in part by a grant from the Fondation pour la Recherche Médicale (DNC20101021008)
文摘Recovery of locomotor behavior following spinal cord injury can occur spontaneously in some vertebrates, such as fish, urodele amphibians, and certain reptiles. This review provides an overview of the current status of our knowledge on the anatomical and electrophysiological changes occurring within the spinal cord that lead to, or are associated with the [e-expression of locomotion in spinally-transected salamanders. A better understanding of these processes will help to devise strategies for restoring locomotor function in mammals, including humans.
基金supported by the Research Grant from the Science and Technology Department of Sichuan, China (2011JY0095)the Construction Project of Southwest University for Nationalities (2011XWD-S071007)
文摘The Chinese giant salamander(Andrias davidianus) is the largest living amphibian in the world. Aeromonas hydrophila strain L602 was isolated from A. davidianus. The 16S rDNA gene of this isolate was amplified using PCR,and the phylogenetic tree was constructed by the neighbor-joining method. Four virulence genes(aerA,aha1,hly and alt) of A. hydrophila were amplified by PCR and drug resistances were tested using Kirby-Bauer disk diffusion method. The results showed that the length of this 16S rDNA sequence was 1453 bp,which showed 99% homology with A. hydrophila. The GenBank accession number was JX155398. Phylogenetic analysis indicated it grouped together with A. hydrophila. Four virulence genes were all detected,indicating that strain L602 was highly virulent. This stain was resistant to four antibiotics(vibramycin,furazolidone,ampicillin and erythromycin),while it was insensitive to streptomycin. Furthermore,this strain was susceptible to six antibiotics(sulfafurazole,ciprofloxacin,penbritin,norfloxacin,florfenicol and enrofloxacin). This study will help to validate the classification and virulence of pathogenic bacteria in amphibians.
基金Supported by the National Natural Science Foundation of China(31360144)the Fund of the Key Laboratory of Biodiversity Preservation,Guiyang University
文摘13 water quality parameters were tested from 38 reaches of 34 counties in Guizhou where Chinese giant salamander(Andrias davidianus) distributed over the past 30 years. Dissolved oxygen and p H were found to be significant determinants of the species distribution in recent years(P<0.05). There was no Chinese giant salamander distribution in the recent five years in rivers with dissolved solids of greater than 415 mg/L, conductivity of greater than 639 us/cm, salinity of greater than 0.31 ppt and total hardness of greater than 150 mg/L. Sensitive to environment, the Chinese giant salamander is an important indicator for environmental quality, so it could be used as one of the environmental indicator. Eutrophication, chemical fertilizer, pesticides and inorganic pollutants may be one of reasons driving wild CGS into extinction.
文摘Although salamanders have been shown to respond to classical conditioning, spatial learning has been largely unstudied. We tested whether salamanders could learn to locate foraging areas by using landmarks. We trained 10 salamanders Plethodon angusticlavius to use landmarks （small rocks） to locate patches within the arena containing food （blackworms Lumbriculus variegatus）. At the comers of each square testing arena were four plastic dishes, one containing blackworms and the other three empty. A rock was placed in front of the dish containing blackworms, and the location of the food-dish was randomly chosen for each training trial. A control group was also trained to feed on blackworms in the presence of a rock, but the rock was positioned randomly among the four dish locations so that the rock was not a reliable landmark for the worms. Although the length of the training period for individual salamanders varied （22-38 trainings per individual）, the mean number of trainings for salamanders in the control and experimental groups was equal （30 training trials）. During testing, no blackworms were present to eliminate any visual or chemical cues emanating directly from the prey. Individuals trained with the rock landmarks spent sig- nificantly more time in the area of the landmark than did control salamanders [Current Zoology 57 （4）： 485-490, 2011].
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National Natural Science Foundation of China,51675268,Xiaolei WangNatural Science Research Fund of Higher Education of Anhui Province,KJ2020A0230,Meng Li+3 种基金open project of key laboratory of green fabrication and surface technology of advanced metal materials,GFST2021KF05,Meng Liopen project of Anhui Province Key Laboratory of special and heavy load robot,TZJQR004-2021,Meng LiNatural Science Foundation of Anhui Province of China,2108085QE228,Meng LiNatural Science Foundation of Anhui Province of China,2108085ME174,Liping Shi。
文摘Salamanders have evolved functions of attaching to a variety of surfaces under wet conditions,but racial diversity may cause a difference in attachment behaviors and epidermal characteristics.The sticking and climbing abilities of the Chinese Fire Belly Newt(CFBN),Chinese Warts Triton(CWT),Spotless Stout Newt(SSN),and Chinese Giant Salamander(CGS)on various surfaces were investigated and compared in terms of epidermal morphology,body size,and wettability.The results indicate that the spotless stout newt has an excellent ability for wet attachment,compared to other salamanders under a certain contact case,resulting from its lower mass/body surface area and more visible epidermal structures.Supplementation with moderate water is beneficial for salamander attachment,and the surface roughness in the flood case also promotes the wet attachment.The CFBN has the most hydrophilic epidermis among the samples,where the water droplet quickly spreads over,presenting a completely wetting case.This study offers a comprehensive understanding of the wet attachments and the epidermal characteristics of salamanders,which is meaningful for the application of bioinspired adhesives.
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The diet composition of the Lycian salamander Lyciasalamandra luschani basoglui across both age and sex groups was studied. Specimens were collected from a small island in the Southeast Aegean Sea. The dominant prey group of juveniles consisted of Collembola, while Coleoptera dominated the diet of males and females. The number and size of prey items consumed by males and females of L. luschani basoglui were quite similar, while juveniles ate fewer items of much smaller size. The numerical abundance along with the four measures of the size of prey permitted discrimination among males, females and juveniles. Although discrimination between adults and juveniles is expected due to dissimilarity in body size, discrimination between males and females remains inexplicable despite their similarity in body size. Future studies should be focused on understanding how and why prey choice differs between sexes in L. luschani basoglui.
基金Supported by National Natural Science Foundation of China(31360144)the Key Laboratory of Biodiversity Preservation,Guiyang University
文摘Chinese giant salamander(CGS, Andrias davidianus) is experiencing the threat of extinction. It is disappearing gradually, because of overharvesting, environmental pollution, specially river pollution, activity of human exploitation, and so on. We conducted community interview fieldworks to collect respondent data from Xieba Country(not reserve) situated in Zhengan County of Guizhou Province, where one of the places known by historical giant salamander records in Guizhou. Through the analysis of the collected data, we created quantitative data of use for conservation management on the local status of salamander populations, and we compared our data with those available data of Y. Pan et al., who investigated the status of CGS in 3 reserves in Guizhou Province in 2015.The conclusions have a similar trend, which proved that the collected data were creditable. Through statistical analysis of the comparison data, the number of wild CGS decreased actually followed the increase of artificial framing.Because of the source of breeding to catch wild CGS, overharvesting was likely the most reason to make wild CGS decline.
