Virus-Encoded MicroRNAs Reveal How Ranavirus Interacts with Amphibian Immune Defense

Ranaviruses are harmful viruses that infect amphibians, fish, and reptiles, and have caused particularly devastating declines in amphibian populations. One particular type of ranavirus, called Frog Virus 3 (FV3), has been extensively studied due to its prevalence and impact on amphibians. Previous research has primarily focused on the virus’s genes, but little attention has been given to the non-coding regions of its genome. This article reviews recent studies that reveal the ability of ranaviruses, including FV3, to encode microRNA (miRNA), a type of regulatory RNA. These viral miRNAs play a crucial role in suppressing frog immune genes, modulating the virus-host interaction, and promoting viral infection. Understanding how ranaviruses use miRNAs to control disease progression is essential for addressing the health threat they pose to wildlife and ecosystems.

Comparative Study of the Biological Activities of the Skin Secretions from Six Common Chinese Amphibians

Water soluble skin secretions of six common Chinese amphibians were studied for their biological and enzymatic activities.The skin secretions of Tylototriton verrucosus,Bombina maxima ,and Bufo andrewsi were found toxic to mice with the intraperitoneal LD 50 of 11 5?mg/kg,18 8?mg/kg,and 264?mg/kg,respectively.No acute lethal toxicities were observed for the skin secretions of Rana nigromaculata,Rana guentheri and Rana limnocharis in a dose up to 500?mg/kg.The lethal toxicities of the skin secretions of T verrucosus and B maxima to mice are in the same grade as those of Viperidae snake venoms.The toxic components in T verrucosus and B maxima skin secretions are the proteins with molecular weights ranging from 3 to 60?kDa.All the skin secretions had both proteolytic activity and trypsin inhibitory activity.The skin secretions from T verrucosus , B maxima and B andrewsi also displayed wide spectrum antimicrobial activity.On the other hand,the skin secretions from B andrewsi and B maxima showed cytotoxicity on human cancer cells.All the six samples had not significant effects on mammalian blood coagulation system.Phospholipase A 2 activity was only found in the skin secretions of T verrucosus .None of these skin secretions showed acetylcholine esterase activity.

Localization of Neuropeptidelike Substances During Embryonic Development in Amphibian

The localization of four neuropeptidelike substances during embryonic development in amphibian was studied by using immuno cytochemical technique. The cells with positive reaction appeared firstly in the endoderm cells during early tailbud stage, and then were detected in connective tissue at the outer portion of gastrointestinal tract during tadpole stage. In the nervous system, the cells with positive reaction were observed in cranial ganglion and glial cells at the outer margin of the brain and in the inner wall of ventricles. They were also frequently observed in the epidermis during late tailbud stage. The relationship between the appearance of neuropeptides in timespatial sequences and the development of nervous system, the neural crest origin of the cells with positive reaction, and the role of epidermal conductivity in neuropeptidelike cells in epiderms were discussed.

全国两栖动物多样性观测网络(China BON-Amphibians)建设进展

两栖动物对环境变化反应敏感,是生物多样性观测的重要指示物种。近年来,欧美国家已制定了生物多样性观测相关标准并实施了一系列观测计划。2011年以来,环境保护部自然生态保护司以环境保护部南京环境科学研究所为牵头单位,联合全国相关科研院所、高等院校、保护机构,构建了全国两栖动物多样性网络,作为全国生物多样性观测网络(China BON)的重要组成部分。该研究介绍了我国两栖动物多样性观测方法,总结了2011年以来全国两栖动物多样性观测工作进展。据115个样区的观测结果显示,观测到的两栖动物共计243种,占我国两栖动物总种数的59.6%。通过观测,发现了破坏两栖动物生境的典型案例。目前我国两栖动物观测网络已初具规模,笔者在介绍观测网络现状的同时也提出了相关建议。

Research proceedings on amphibian model organisms

Model organisms have long been important in biology and medicine due to their specific characteristics. Amphibians, especially Xenopus, play key roles in answering fundamental questions on developmental biology, regeneration, genetics, and toxicology due to their large and abundant eggs, as well as their versatile embryos, which can be readily manipulated and developed in vivo. Furthermore, amphibians have also proven to be of considerable benefit in human disease research due to their conserved cellular developmental and genomic organization. This review gives a brief introduction on the progress and limitations of these animal models in biology and human disease research, and discusses the potential and challenge of Microhyla fissipes as a new model organism.

Endemic Amphibians and Their Distribution in China

Amphibians are good indicators of ecosystem health. Updating the information of endemic species in time and understanding their spatial distributions are necessary for the development of integrative conservation strategies and the elucidation of geographic patterns of amphibians. We analyzed the diversity and distributions of the endemic amphibians in China based on a database of specimen records, recently published literature, and field surveys. Two hundred and sixty two endemic species of amphibians, belonging to 59 genera in 12 families and two orders, are recognized. They account for 67% of the total number of amphibian species in China, with the family Megophryidae possessing the largest number of endemics. There are also 17 genera endemic to China. Across provinces, the species richness of endemics shows five levels with a hierarchical diversification. Sichuan has the largest number of endemics, while Heilongjiang and Jilin have no endemic species. Alternatively, whether on the level of endemic genus or species, the highest diversity occurs in the Western Mountains and Plateau Subregion. The distribution ranges of most endemic species cover ≤ 4 provinces or zoogeographic subregions. Additionally, the species richness of endemics along an elevational gradient shows a bell-shaped pattern with the peak around 800 m. Most endemic species are distributed in areas of low to mid elevation(c. 700–1 500 m), while 36 species are distributed up to 3 000 m. Endemic species richness decreases with increasing of elevation range. Species at mid elevations display large range sizes, while species at lower and higher elevations exhibit smaller ranges. Our results are to be beneficial for further exploration of the underlying mechanisms of distributional patterns of amphibians in China. This study highlights a need to promote conservation programs for Chinese endemic amphibians due to their narrow distribution ranges and potential threats.

Investigating the Effectiveness of Road-related Mitigation Measures under Semi-controlled Conditions:A Case Study on Asian Amphibians

Road traffic is the main factor causing the decline in amphibian populations worldwide. The proper design of an amphibian tunnel is one of the most efficient measures to mitigate the negative impacts of road traffic on amphibians. However, no study has investigated the effectiveness of amphibian tunnels under semi-controlled conditions in Asian amphibians. Here, we selected two representative amphibian species, the Chinese brown frog, Rana chensinensis, and the Asiatic toad, Bufo gargarizans, which suffer the most severe road mortality along the roads in Northeast China. We placed experimental arrays of culverts of various sizes(diameters of 1.5, 1, and 0.5 m for circular culverts; side lengths of 1.5, 1, and 0.5 m for box culverts), and substrate type(soil, concrete, and metal) to examine the preferences of both species during the migratory season between May and September in 2016 and 2017. The results revealed that the Chinese brown frog preferred mid-and large-sized culverts as well as soil culverts. We concluded that culverts with a side length ≥ 1 m, lined with soil, and accompanied by a ≥ 0.4 m high guide drift fence and ≤ 45° gradient on the roadside ditch wall would best facilitate road crossings for both species and likely for other amphibian species in Northeast China.

Progress and Prospects for Studies on Chinese Amphibians

This work summarizes the history and progress of the studies on Chinese amphibians since they first appeared in the Chinese literature.A wide range of research has been carried out,including the history of the definition of amphibians,faunal surveys,systematic research,ecological research,biochemical research(isozyme and other proteins or peptides,chromosomes,DNA),anatomical research,embryological research,phylogenetic and zoogeographical research,and many others such as ultrastructure of organs,crossbreeding test,regeneration of organs,abnormality survey,acoustics,fossils,sperm ultrastructure and parasites.In addition,the prospects for studies on Chinese amphibians in future are proposed in this paper.

Amphibian Species Contribute Similarly to Taxonomic, but not Functional and Phylogenetic Diversity: Inferences from Amphibian Biodiversity on Emei Mountain

Understanding the relationships between species, communities, and biodiversity are important challenges in conservation ecology. Current biodiversity conservation activities usually focus on species that are rare, endemic, distinctive, or at risk of extinction. However, empirical studies of whether such species contribute more to aspects of biodiversity than common species are still relatively rare. The aim of the present study was to assess the contribution of individual amphibian species to different facets of biodiversity, and to test whether species of conservation interest contribute more to taxonomic, functional, and phylogenetic diversity than do species without special conservation status. To answer these questions, 19 000 simulated random communities with a gradient of species richness were created by shuffling the regional pool of species inhabiting Emei Mountain. Differences of diversity values were then computed before and after removing individual species in these random communities. Our results indicated that although individual species contributed similarly to taxonomic diversity, their contribution to functional and phylogenetic diversity was more idiosyncratic. This was primarily driven by the diverse functional attributes of species and the differences in phylogenetic relationships among species. Additionally, species of conservation interest did not show a significantly higher contribution to any facet of biodiversity. Our results support the claims that the usefulness of metrics based only on species richness is limited. Instead, assemblages that include species with functional and phylogenetic diversity should be protected to maintain biodiversity.

Amphibians and Reptiles of Luzon Island,V:The Herpetofauna of Angat Dam Watershed,Bulacan Province,Luzon Island,Philippines

We report amphibian and reptile distribution records based on recent biodiversity surveys conducted at the Angat Watershed Reservation, Bulacan Province, Luzon Island, Philippines. This watershed constitutes the principal water source for Manila, the Philippines＇ largest metropolitan area. As virtually nothing is known of the herpetological diversity of the immediate area and the surrounding Bulacan Province, all species recorded as part of our surveys constitute major geographical records and/or significant range extensions. Our data result in a total of 63 new records of amphibian （19 frogs） and reptile （22 lizards, 2 turtles, and 20 snakes） species for this protected area （and immediate vicinity） that serves as a watershed for the major metropolitan area of Manila and surrounding cities. Together with the few previous literature records, our new records bring the total number of amphibian and reptile species for Bulacan Province to 68. We discuss several strategies for future survey work （focusing on habitat type, seasonal variation, and elevational variability） that we anticipate will result in increased knowledge of diversity within the Angat Watershed Reserve. The impressive level of herpetological diversity within such a small area, so close to Metro Manila, emphasizes that the diversity and distribution patterns of amphibians and reptiles from Luzon are still poorly known and in need of further study.

Species Diversity and Elevational Distribution of Amphibians in the Xianxialing and Wuyishan Mountain Ranges,Southeastern China

The species diversity and altitudinal distribution of amphibians along an eleva tional gradient of 200-1600 m in the Xianxialing and Wuyishan Mountain Ranges in Southeastern China were investiga ted through time-constra ined visual surveys along 32 transect lines in 9 survey areas,in which the ha bitat types were also recorded.A total of 27 amphibian species belonging to 19 genera,7 families,and 2 orders were found.The species diversity of the amphibians plateaued at low elevation,and the altitudinal boundary of their distribution was at 800 m.Their species compositions were dissimilar in the two mountain ranges probably beca use the annual average temperature and annual rainfall were different in both areas.The eleva tional Rapoport's rule demonstrated that the species range size of the amphibians expanded as the elevation increased in both mountain ranges.The results of the cross species method supported the rule only when the influence of the low-frequency occurrence proba bility of an investigated species was excluded,whereas those of the Steven's method strongly corroborated the rule rega rdless of the incidental occurrence or absence of the species.

Amphibians Testing Negative for Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans on the Qinghai-Tibetan Plateau,China

A disease caused by the fungi Batrachochytrium dendrobatidis（Bd） and Batrachochytrium salamandrivorans（Bsal） is responsible for recent worldwide declines and extinctions of amphibian populations.The Qinghai-Tibetan Plateau（QTP） is aglobal biodiversity hotspot,yet little is known about the prevalence of Bd and Bsal in this region.In this study,we collected 336 non-invasive skin swabs from wild amphibians（including an exotic amphibian species） on the QTP.In addition,to assess the historical prevalence of Bd and Bsal on the QTP,we collected 117 non-invasive skin swabs from museum-archived amphibian samples（from 1964-1982） originating from the QTP.Our results showed all samples to be negative for Bd and Bsal.The government should ban the potentially harmful introduction of non-native amphibian species to the QTP and educate the public about the impacts of releasing exotic amphibians from chytridinfected areas into native environments of the QTP.

Amphibian and reptilian distribution patterns in the transitional zone between the Euro-Siberian and Central Asia Subrealms

There exist some controversies over the larger zoogeographic divisions of the arid areas of Central Asia, whose characteristics include complex ecological environments, complex fauna origins and unique patterns of animal distribution. The aim of this study was to determine, using quantitative analysis, the distribution patterns of amphibians and reptiles in the arid areas of Central Asia, whose various physiographical regions were divided into 17 Operative Geographical Units （OGUs）. Based on the presence or absence of 52 amphibian and reptile genera in the 17 OGUs, and by making use of the Czekanowski Similarity Index, the Baroni-Urbani and Buser＇s Similarity Index, and the strong and weak boundary test, we studied the biotic boundaries within these contested regions. In accordance with our results, the classification dendrogram was divided into two main branches. One branch is composed of the northern OGUs of the Altai Mountains which are a part of the Euro-Siberian Subrealm. The other branch includes all of the OGUs south of the Altai Mountains, which belong to the Central Asia Subrealm. There is a significantly weak biotic boundary （DW〉0, GW〉GS, P〈0.01） between the Euro-Siberian Subrealm and the Central Asia Subrealm that corre- sponded to the transitional zones. The boundary between the two subrealms runs along the Altai Mountains, the Sayan Mountains, the Hangai Mountains and the Mongolian Dagurr Mountains. The boundaries between the main branches in the Central Asia Subrealm are weak, reflecting the widespread existence of transitional zones in the arid areas of Central Asia. The Tianshan Mountains should be elevated to form its own separate region, ＂the Middle Asian Mountain Region＂, which, due to its special fauna and environment, would be classified at the same level as the Mongolia-Xinjiang Region. With the approach of creating a cluster analysis dendogram based upon the genera of amphibians and reptiles, the relationship of these higher level zoogeographical divisions was successfully resolved and the error of long-branch attraction was also avoided. With our clustering dendrogram as the foundation, the in- dependence test was applied to strong and weak boundaries, and this resolved the problem of where to attribute the transition areas and revealed as well the barrier effect that physical, geographic boundaries have upon amphibians and reptiles. The approach of combining genera clustering analysis with a statistical boundary test should be applicable not only to the distribution patterns of other animal groups, but also to delineating large-scale zoogeographical divisions.

An Integrative Taxonomy of Amphibians of Nepal:An Updated Status and Distribution

Amphibians are declining worldwide.At the same time,each year many species of amphibians are described,indicating that biological diversity on Earth remains poorly understood.This is especially true for mountainous regions,such as the Himalayas,which are also regarded as a biodiversity hotspot.However,it is most likely that the current diversity of amphibians in Nepal is highly underestimated.Amphibian inventories by the past researchers primarily used phenotypic characters as the basis for species identification.However,the application of molecular systematics methods to taxonomic studies has successfully uncovered the taxonomic status of several cryptic taxa.This study used both molecular(16 S rDNA sequences)and morphological comparisons and estimated the diversity of amphibians from Nepal.This study reports the occurrence of 38 species of amphibians based on both molecular and morphological comparisons.Among them,three species were recorded for the first time in Nepal.This study also invalids the taxonomic status of Sphaerotheca paschima.This study highlights the importa nce of integrative taxonomic approaches that help to resolve the current taxonomic ambiguities of Nepalese amphibians.

Studies on the Effects of Deltamethrin on Sodium Net Transport Through the in vivo Amphibian Skin

The action of micromolar concentrations of Deltamethrin on sodium net transport through the in vivo skin of the South American toad Bufo arenarum was studied. The effect of pure ethanolic insecticide solutions and commercial formulations when applied on the mucosal surface was assayed. Deltamethrin provoked a concentration-independent inhibition; the highest inhibition was found at the lowest concentrations. At highest concentrations of the insecticide the J Na was not altered

Does wetland watershed land use influence amphibian larval development? A relevant effect of agriculture on biota

Agriculture practices have been widely proposed as the major cause of amphibian population decline. However, the majority of these results have been based on laboratory experiments. The present study was conducted to test the repercussion of wetland sediment provenance on amphibian larval development.Bufo bufo larvae were used in two dif ferent treatments in an outdoor experiment, the ?rst one using sediment from one wetland surrounded by intensive agricultural practices, and the second using sediment with no record of agrochemical uses. A negative ef fect was observed in the agricultural treatment, from subcellular to individual level. The results showed that the sediment from agricultural practices watershed generates a reduction in survival. Furthermore, individuals that developed under this treatment showed a lower total length and a delay in the time necessary to complete metamorphosis; these features are connected with recruitment success. In the same way, biochemical analysis showed high values of lipid peroxidation in metamorphs developing in sediments from an agricultural area. Finally, the results obtained highlight the importance of considering the sediments, not only the water, as origin treatment, allowing us to understand the consequences on amphibian populations that inhabit areas af fected by intensive agriculture.

A Revised Checklist of Amphibians and Reptiles in Camiguin Sur,Misamis Oriental,Mindaanao,Philippines

The Philippines is listed as one of the world's megadiverse countries despite its small size.Conversely,it is also on the list of global biodiversity conservation hotspots.With the threat of extinction at an all-time high,better understa nding of the archipelago's biodiversity will provide invalua ble baseline information for proper conservation efforts.Here we provide an upda ted checklist on the herpetological biodiversity of Ca miguin Sur,Misa mis Oriental,Minda nao,Philippines.Field surveys and specimen collection from the municipality of Mambajao resulted in a total of 28 species(13 anurans,11 lizards,and four snakes)-all well represented by voucher specimens.Our data provides seven additional species records,upda ting the island's total amphibian and reptile species count to 57,with about half Philippine endemic.Included in the new records are three invasive alien species of amphibians:The Cane Toad Rhinella marina,the Greenhouse Frog Eleutherodatylus planirstris,and the Asiatic Painted Narrowmouth Toad Kaloula pulchra.

Perspectives on studying molecular adaptations of amphibians in the genomic era

Understanding the genetic mechanisms underlying particular adaptations/phenotypes of organisms is one of the core issues of evolutionary biology.The use of genomic data has greatly advanced our understandings on this issue,as well as other aspects of evolutionary biology,including molecular adaptation,speciation,and even conservation of endangered species.Despite the well-recognized advantages,usages of genomic data are still limited to non-mammal vertebrate groups,partly due to the difficulties in assembling large or highly heterozygous genomes.Although this is particularly the case for amphibians,nonetheless,several comparative and population genomic analyses have shed lights into the speciation and adaptation processes of amphibians in a complex landscape,giving a promising hope for a wider application of genomics in the previously believed challenging groups of organisms.At the same time,these pioneer studies also allow us to realize numerous challenges in studying the molecular adaptations and/or phenotypic evolutionary mechanisms of amphibians.In this review,we first summarize the recent progresses in the study of adaptive evolution of amphibians based on genomic data,and then we give perspectives regarding how to effectively identify key pathways underlying the evolution of complex traits in the genomic era,as well as directions for future research.

Analysis on the Impact of Amphibian Export in South Africa on Global Chytrid Distribution: Taking China as an Example

Chytridiomycosis, caused by chytrid fungus, is a dominant infectious disease in anura after metamorphosis. Previous evidence suggests that Africa is the birthplace of chytridiomycasis. At present, with the increasingly rapid development of international trade in amphibians, the rapid spread and widespread outbreak of chytridiomycosis poses a huge threat to amphibian populations in the world. In this study, according to the entry-exit inspection and quarantine standards of the people~ Republic of China, the impact of amphibian importation from South Africa on ecological security in China was analyzed based on release assessment, contact exposure assessment and consequence assessment, to investigate the risk of chytrid fungus through the importation of amphibians from South Africa to China and the possibility of the colonization and dissemination of chytrid fungus after the introduction. The result of risk assessment of chytrid fungus through the importation of amphibians from South Africa to China and the result of possibility assessment of the colonization and dissemination of chytrid fungus after the introduction were both identified as ＂ moderate＂, which indicated that the importation of amphibians from South Africa to China exhibited a certain risk, and the introduction of chytrid fungus in China would cause certain risk of colonization and dissemination.

Ecological Risk Assessment of Amphibian Chytridiomycosis from Europe to China

[Objective] Chytridiomycosis has become one of the important infectious diseases of amphibians around the world since 1998. So far, amphibian chytridiomycosis has led to regional extinction of nearly 200 kinds of amphibians and reduced 50% of amphibian populations in the world. In recent years, amphibian chytridiomycosis occurs frequently in Europe. For instance, amphibian chytridiomycosis cases have been found successively in Spain, Germany and Italy, especially in Germany. Currently, with the development of prosperous world trade, the spread of chytrid fungus through trade between countries has posed a huge poten- tial threat to the ecological security of amphibians in China. [ Method] According to entry-exit inspection and quarantine standards of the people＇s Republic of China, in this paper, release assessment, contact exposure assessment and consequence assessment technologies were integrated to obtain the risk assessment result of chytrid fungus from Europe and the possibility assessment result of the colonization and dissemination of chytrid fungus after the introduction. [ Result] The risk assessment result of chytrid fungus from Europe to China was identified as ＂moderate＂, and the possibility assessment result of the colonization and dissemination of chytrid fungus after the introduction was identified as ＂high＂. [ Conclusion] The importation of amphibians from Europe to China exhibits a certain risk. The intro- duction of chytrid fungus in China will cause a high risk of colonization and dissemination.