Saccharomyces cerevisiae additions normalized hemocyte differential genes expression and regulated crayfish (Procambarus clarkii) oxidative damage under cadmium stress.

Because China produces the most crayfish in the world, safe solutions must be improved to mitigate the risks of ongoing heavy metal stressors accumulation. This study aimed to use Saccharomyces cerevisiae as a bioremediation agent to counteract the harmful effect of cadmium (Cd) on crayfish (Procambarus clarkia). Our study used three concentrations of S. cerevisiae on crayfish feed to assess their Cd toxicity remediation effect by measuring total antioxidant capacity (TAC) and the biomarkers related to oxidative stress like malondialdehyde (MDA), protein carbonyl derivates (PCO), and DNA-protein crosslink (DPC). A graphite furnace atomic absorption spectroscopy device was used to determine Cd contents in crayfish. Furthermore, the mRNA expression levels of lysozyme (LSZ), metallothionein (MT), and prophenoloxidase (proPO) were evaluated before and following the addition of S. cerevisiae. The results indicated that S. cerevisae at 5% supplemented in fundamental feed exhibited the best removal effect, and Cd removal rates at days 4th, 8th, 12th, and 21st were 12, 19, 29.7, and 66.45%, respectively, which were significantly higher than the basal diet of crayfish. The addition of S. cerevisiae increased TAC levels. On the other hand, it decreased MDA, PCO, and DPC, which had risen due to Cd exposure. Furthermore, it increased the expression of proPO, which was reduced by Cd exposure, and decreased the expression of LSZ and MT, acting in the opposite direction of Cd exposure alone. These findings demonstrated that feeding S. cerevisiae effectively reduces the Cd from crayfish and could be used to develop Cd-free crayfish-based foods.

A new species of Xenophrys (Amphibia, Anura, Megophryidae) from southern Tibet, China.

A new species of Xenophrys is described from Yadong County, Tibet Autonomous Region, China based on morphological and molecular evidence. Phylogenetic analyses based on the mitochondrial genes 16S rRNA and COI indicated that this new species represents an independent lineage and the minimum p-distance based on 16S rRNA between this species and its congeners is 4.4%. Additionally, the new species is distinguished from its congeners by a combination of the following morphological characters: (1) small body size, SVL 17.9-22.2 mm in adult males and SVL 23.4 mm in the single adult female; (2) tympanum indistinct, supratympanic fold distinct; (3) canthus rostralis well-developed, snout tip far beyond the margin of the lower lip; (5) pupil vertical; (6) vomerine teeth present, maxillary teeth present; (7) tongue notched posteriorly; (8) supernumerary tubercles absent, subarticular, metacarpal and metatarsal tubercles indistinct; (9) relative finger lengths I < II < IV < III, finger tips rounded, slightly expanded relative to digit widths; (10) toes with narrow lateral fringes and tarsal folds; (11) a dark triangular marking with light edge between eyes, a dark ")("-shaped marking, with light edge, present on center of dorsum, pectoral glands on sides of the breast.

Molecular phylogeny reveals cryptic diversity in Sibynophis from China (Serpentes: Sibynophiidae).

The elucidation of species diversity and distribution is critical within the fields of evolution, genetics, and conservation. The genus Sibynophis contains rare snakes that have historically received little attention. In this study, we conducted comprehensive sampling and use both mitochondrial and nuclear genetic markers to explore Sibynophis species diversity within China. Our findings revealed that S. c. miyiensis should be considered synonymous with S. c. grahami, and S. c. grahami should be gave a specific rank as S. grahami. In addition, we discovered S. triangularis was new to China and Myanmar. Based on the specimens and molecular phylogeny results, we redefined the species distribution boundaries of each Chinese species.

Rapid genetic divergence and mitonuclear discordance in the Taliang knobby newt ( Liangshantriton taliangensis, Salamandridae, Caudata) and their driving forces.

The Hengduan Mountains Region (HMR) is the largest "evolutionary frontier" of the northern temperate zone, and the origin and maintenance of species in this area is a research hotspot. Exploring species-specific responses to historical and contemporary environmental changes will improve our understanding of the role of this region in maintaining biodiversity. In this study, mitochondrial and microsatellite diversities were used to assess the contributions of paleogeological events, Pleistocene climatic oscillations, and contemporary landscape characteristics to the rapid intraspecific diversification of Liangshantriton taliangensis, a vulnerable amphibian species endemic to several sky-island mountains in the southeastern HMR. Divergence date estimations suggested that the East Asian monsoon, local uplifting events (Xigeda Formation strata), and Early-Middle Pleistocene transition (EMPT) promoted rapid divergence of L. taliangensis during the Pleistocene, yielding eight mitochondrial lineages and six nuclear genetic lineages. Moreover, population genetic structures were mainly fixed through isolation by resistance. Multiple in situ refugia were identified by ecological niche models and high genetic diversity, which played crucial roles in the persistence and divergence of L. taliangensis during glacial-interglacial cycles. Dramatic climatic fluctuations further promoted recurrent isolation and admixing of populations in scattered glacial refugia. The apparent mitonuclear discordance was likely the result of introgression by secondary contact and/or female-biased dispersal. Postglacial expansion generated two major secondary contact zones (Ganluo (GL) and Chuhongjue (CHJ)). Identification of conservation management units and dispersal corridors offers important recommendations for the conservation of this species.

A new species of bush frog (Anura, Rhacophoridae, Raorchestes) from southern Xizang, China.

Based on molecular evidence and morphological data, we describe a new species Raorchestes yadongensis sp. nov. from Yadong County, Xizang Autonomous Region, China. The new species can be distinguished based on a combination of the following characters: (1) small body size, SVL 17.8-24.1 mm in adult males; (2) head wider than long; (3) eye diameter about three times as much as tympanum diameter; (4) tympanum distinct; (5) fingers with rudimentary webbing and narrow lateral dermal fringes; relative finger lengths I < II < IV < III; number of subarticular tubercles in fingers 1, 1, 2, 1; (6) toes with rudimentary webbing and narrow lateral dermal fringes; relative toe lengths I < II < III < V < IV; number of subarticular tubercles in toes 1, 1, 2, 3, 2; inner metatarsal tubercle distinct, outer metatarsal tubercle absent; (7) tips of fingers and toes present discs, and discs pale brown or yellow in life; (8) tibiotarsal articulation reaching the tip of snout when adpressed; (9) milky nuptial pad present on the dorsal surface of first finger; (10) dorsal surface light brown with white warts, ventral surface with irregular white patches. The new species is currently known in Yadong County, Xizang, China, but may also occur in neighboring Bhutan and India. A key to Chinese species of the genus Raorchestes is also provided.

Complete mitochondrial genome of the Alpine Metacarpal-tubercled Toad Leptobrachella alpina (Amphibia, Anura, Megophryidae).

The complete mitochondrial genome of the Leptobrachella alpina Fei, Ye, and Li 1990, was assembled for the first time. The mitogenome of this species was 17,763 bp in length, containing 13 protein-coding genes, two ribosomal RNA genes (12S rRNA and 16S rRNA), 22 transfer RNA genes (tRNA), and a non-coding control region (D-loop). The base content of the mitogenome was that A, T, G, and C occupied 28.5%, 30.8%, 15.1%, and 25.6%, respectively. The phylogenetic analysis was conducted based on 17 complete mitogenome sequences of the family Megophryidae by the Bayesian inference approach. The phylogenetic tree suggested that Leptobrachium and Oreolalax clustered into a clade and formed a sister group with Leptobrachella. This work is critical for the further genetic research and conservation of this species.

Fatter or stronger: Resource allocation strategy and the underlying metabolic mechanisms in amphibian tadpoles.

The allocation of resources between storage and somatic growth is an essential physiological phenomenon in animals. Allocation mechanisms have broad theoretical and applied implications. The real-time resource allocation patterns in animals remain to be elucidated, and there is limited understanding of the metabolic mechanisms. We investigated the resource allocation strategy of Rana omeimontis tadpoles. Their ontogenetic fat accumulation began when body weight increased to 30-50 mg, at which time storage had a high priority in resource allocation. Beyond this weight range, somatic growth accelerated but storage investment was maintained, resulting in a positive correlation between body fat index and body weight at the population level. This pattern could be explained by assuming a positive relationship between storage abundance and growth investment, and this was supported by the prioritized increment of body fat to body weight when tadpoles were provided with increased food. At the metabolic level, hepatic fat accumulation was accompanied by upregulated utilization of fat storage, and the tadpoles presented lipid-based energy metabolism. Activating the mobilization of hepatic fat storage promoted somatic growth. In short, the liver is like a reservoir with valves that regulate energy flow for downstream developmental processes. These results provide novel mechanistic insights into resource allocation.

Niche divergence of evolutionarily significant units with implications for repopulation programs of the world's largest amphibians.

The niche divergence and potential climate change-induced loss of evolutionarily significant units (ESUs) of flagship amphibian species in China, the Chinese giant salamander clade, were investigated. We tested niche-related ecological hypotheses and identified suitable habitats that are essential for the conservation of ESUs in response to future climate change according to ecological niche models (ENMs). We predicted the localized habitat loss crisis of ESUs induced by global climate heating using the predicted climate derived from two representative concentration pathway (RCP) scenarios 2.6 and 8.5, respectively. In our study, a niche conservatism pattern was found between the two distinctive northern and southern ESUs with sufficient distributional records, but their niches were not equivalent. Furthermore, there was neither abrupt environmental change in nor remarkable biogeographic barriers between the suitable habitats of the species, as indicated by random linear, blob and ribbon range-breaking tests. Under the low-emission scenario RCP2.6, the northern ESU had a moderate loss of suitable range, while the southern ESU had range expansion in the 2070s. The climatic velocities were low in the ranges of both ESUs. However, under the high-emission scenario RCP8.5, the climatic velocities were found to become larger in the suitable ranges of both ESUs. Moreover, the northern ESU had severe habitat loss, bringing it to the edge of extinction, while the southern ESU also had intensified range loss. Considering this, climatic velocity can be an effective indicator of range loss. We argued conclusively that conservation prioritization of ESUs should effectively take into account the underlying geographic and ecological mechanisms driving the speciation process. The conservation of ESUs should consider the conservation of both evolutionary potential and ecological adaptation capacity of each lineage. The present study provided practical guidelines for repopulation programs for endangered species and the conservation of evolutionary diversity.

Description and initial characterization of metatranscriptomic nidovirus-like genomes from the proposed new family Abyssoviridae, and from a sister group to the Coronavirinae, the proposed genus Alphaletovirus.

Transcriptomics has the potential to discover new RNA virus genomes by sequencing total intracellular RNA pools. In this study, we have searched publicly available transcriptomes for sequences similar to viruses of the Nidovirales order. We report two potential nidovirus genomes, a highly divergent 35.9 kb likely complete genome from the California sea hare Aplysia californica, which we assign to a nidovirus named Aplysia abyssovirus 1 (AAbV), and a coronavirus-like 22.3 kb partial genome from the ornamented pygmy frog Microhyla fissipes, which we assign to a nidovirus named Microhyla alphaletovirus 1 (MLeV). AAbV was shown to encode a functional main proteinase, and a translational readthrough signal. Phylogenetic analysis suggested that AAbV represents a new family, proposed here as Abyssoviridae. MLeV represents a sister group to the other known coronaviruses. The importance of MLeV and AAbV for understanding nidovirus evolution, and the origin of terrestrial nidoviruses are discussed.

Daytime driving decreases amphibian roadkill.

Roadkill has gradually become a common factor that has contributed to the decline of amphibians, and traffic volume is an important parameter that can be used to determine the impacts of roads. However, few researchers have studied the effects of either daily or nightly traffic volume on amphibian roadkill in China. Hence, as an essential step for implementing mitigation measures, we conducted 77 road surveys along 10 km of road in the Wanglang National Nature Reserve (NNR) to determine the temporal and spatial distribution patterns of amphibian road mortality. In total, 298 dead individuals (Bufo andrewsi and Rana chensinensis) were observed on the road from April to October in 2017 and during June and August in 2015 and 2016. B. andrewsi had the highest number of records (85.2%) and was more vulnerable to road mortality than R. chensinensis. Amphibian fatalities mainly occurred during the breeding season in April, but there was an additional concentration of B. andrewsi roadkill in June and July. There was a significantly positive correlation between amphibian road mortality and mean night-time traffic volume. Roadkill hotspots were non-randomly distributed throughout the study area and were mainly concentrated in the road sections near the breeding pools. Therefore, to effectively mitigate the effects of road mortality in the Wanglang NNR, measures should be implemented both during hot moments and at hotspots. First, based on roadkill hot moments, during the breeding season (in April) and in June and July, the Wanglang NNR should establish temporary traffic restraints at night. Second, based on roadkill hotspots, culverts should be established in areas near breeding pools adjacent to roads, and barrier walls should be installed to guide amphibians into the culverts.

Effects of long-term preservation on amphibian body conditions: implications for historical morphological research.

Measurements of historical specimens are widely applied in studies of taxonomy, systematics, and ecology, but biologists often assume that the effects of preservative chemicals on the morphology of amphibian specimens are minimal in their analyses. We compared the body length and body mass of 182 samples of 13 live and preserved (up to 10 years) anuran species and found that the body length and body mass of preserved specimens significantly decreased by 6.1% and 24.8%, respectively, compared to those measurements of their live counterparts. The changes in body length and mass also exhibited highly significant variations between species. Similarly, there were significant differences in shrinkage of body length and body mass between sexes, where males showed greater shrinkage in body length and body mass compared to females. Preservation distorted the magnitude of the interspecific differences in body length observed in the fresh specimens. Overall, the reduction in body length or mass was greater in longer or heavier individuals. Due to the effects of preservation on amphibian morphology, we propose two parsimonious conversion equations to back-calculate the original body length and body mass of studied anurans for researchers working with historical data, since morphological data from preserved specimens may lead to incorrect biological interpretations when comparing to fresh specimens. Therefore, researchers should correct for errors due to preservation effects that may lead to the misinterpretation of results.

Complete mitochondrial genome of the Leishan moustache toad, Vibrissaphora leishanensis (Anura: Megophryidae).

The complete mitogenome of Leishan moustache toad, Vibrissaphora leishanensis, is determined. The mitogenome size is 17,485 bp, containing 13 protein-coding genes, 2 rRNA genes, 23 tRNA genes and a control region (D-loop). The base composition of the whole genome is 28.1% A, 32.6% T, 24.4% C and 14.8% G. As observed in this genus before, this mitogenome also appears a tandem duplication of tRNAMet gene. This study will provide fundamental data for further research to resolve population genetics of this species and systematic problems of the genus Vibrissaphora.