There are many PCR-based methods for animal species identification; however, their detection numbers are limited or could not identify unknown species. We set out to solve this problem by developing a universal primer PCR assay for simultaneous identification of eight animal species, including goat, sheep, deer, buffalo, cattle, yak, pig, and camel. In this assay, the variable lengths of mitochondrial DNA were amplified using a pair of universal primers. PCR amplifications yielded 760 bp, 737 bp, 537 bp, 486 bp, 481 bp, 464 bp, 429 bp, and 359 bp length fragments for goat, sheep, deer, buffalo, cattle, yak, pig, and camel, respectively. This primer pair had no cross-reaction with other common domestic animals and fish. The limit of detection varied from 0.01 to 0.05 ng of genomic DNA for eight animal species in a 20 µl PCR mixture. Each PCR product could be further digested into fragments with variable sizes and qualitative analysis by SspI restriction enzyme. This developed PCR-RFLP assay was sufficient to distinguish all targeted species. Compared with the previous published related methods, this approach is simple, with high throughput, fast processing rates, and more cost-effective for routine identification of meat in foodstuffs.

Habitat fragmentation caused by human activities poses a serious threat to the genetic diversity of populations. Artificial islands of known age are ideal model systems that offer a unique opportunity to elucidate the consequences of habitat fragmentation and the effects of island area and isolation on genetic diversity and structure of populations. The Thousand Island Lake (TIL) in Zhejiang Province, East China, is a large reservoir that was formed in 1959 by the damming of the Xinan River to construct a hydroelectric power station. We used sequence-related amplified polymorphism (SRAP) molecular markers to study the genetic diversity of a species, Lycosa coelestris, with low dispersal ability in the TIL. Five SRAP primer combinations were used to genotype 42 individuals of L. coelestris from 14 islands to estimate its population genetic diversity and structure. The result showed that 5 SRAP primer combinations amplified 85 bands with 84 (98.82%) polymorphism. The percentage of polymorphic bands (PPB) at the population level ranged from 15.29% to 38.82%, the observed number of alleles (N _a) from 1.1529 to 1.3882, the effective number of alleles (N _e) from 1.0952 to 1.3392, Neis gene diversity index (H) from 0.0582 to 0.1784 (average 0.0992), and Shannons information index (I) from 0.0881 to 0.2524 (average 0.1480). The islands area or shape index had significant correlations with PPB, H, and I. The genetic differentiation coefficient (G _st) among populations was 0.7293 and gene flow (N _m) among populations was 0.1856, which means high genetic differentiation had appeared in the TIL. The analysis of molecular variance showed that the main variance between populations was 57.33% and that within populations was 42.67%. The Mantel test suggested that there was significant association between genetic distance and geographic distance (r=0.7757, P <0.01). The structure and principle components analysis showed that the L. coelestris populations in the TIL can be divided into 6 groups, and populations were geographically closer to one another in each group. These results indicated that island area and shape mainly affect the genetic diversity of L. coelestris populations, and geographic isolation mainly affects genetic differentiation at TIL.

Context Habitat fragmentation reshapes biodiversity not only by reducing species richness, but also by altering patterns of community differentiation across space. Although island biogeography theory predicts strong effects of habitat area and isolation on species distributions, it remains insufficiently resolved how these spatial attributes structure β diversity and its turnover and nestedness components, across multiple taxa within a shared fragmented landscape. Objectives Here, we ask whether patch area and isolation regulate β diversity through consistent mechanisms across taxa, and whether species’ dispersal ability modulates the balance between turnover- and nestedness-driven β diversity in fragmented landscapes. Methods Using a land-bridge island system formed by reservoir inundation in eastern China, we quantified β diversity patterns for woody plants, insects, spiders, and breeding birds. We focused exclusively on spatial attributes derived from island biogeography theory, patch area and isolation, and partitioned overall β diversity into turnover and nestedness components to evaluate their relative contributions across taxa and dispersal groups. Results Maximum patch area emerged as the dominant predictor of β diversity in mobile taxa, whereas woody plants were more strongly influenced by maximum isolation and minimum patch area. Across all taxa, increasing patch area consistently shifted β diversity from turnover-dominated to nestedness-dominated patterns. Within taxa, dispersal ability further modulated these patterns: high-dispersal groups exhibited higher turnover contributions, whereas low-dispersal groups were characterized by a stronger reliance on nestedness-driven β diversity. Conclusions Our results show that pacth area and isolation regulate regional biodiversity primarily by redistributing the relative importance of turnover and nestedness, rather than by uniformly increasing compositional dissimilarity. By integrating β diversity mechanisms into island biogeography and fragmentation theory, this study reveals how large and small patches play complementary, process-dependent roles in sustaining biodiversity, thereby extending the SLOSS debate beyond species richness toward a mechanistic, multi-taxon framework.

To investigate the effect of feeding on hibernating Hirudo nipponia, metagenomic sequencing was performed on the microorganisms collected from the digestive tract of H. nipponia individuals that were fed (FW) or starving (SW) before hibernation. In addition, the salivary gland tissues were obtained from these individuals to conduct transcriptome sequencing. Results showed that feeding before hibernation increased the relative abundance of Bacteroidetes and Proteobacteria at the phylum level and that of Aeromonas, Mucinivorans, Bacteroides, and Desulfovibrio at the genus level. Functional prediction results indicated that feeding before hibernation not only improved metabolic capacity but also increased the susceptibility of H. nipponia to pathogens. Among the 133,082 unigenes obtained by transcriptome sequencing, a total of 2801 differentially expressed genes (DEGs) were found, of which 355 were up-regulated and 2446 were down-regulated; the expression patterns of 15 selected DEGs were validated by qRT-PCR. Results from the GO and KEGG enrichment analyses showed that a majority of these DEGs were involved in the signal transduction pathways. This study established a basis for H. nipponia breeding during hibernation through analyses of the abundance of microorganisms in the digestive tract and the gene expression pattern of salivary glands by high-throughput sequencing. The findings also revealed the effect of feeding on the expression of both gastrointestinal microorganisms and salivary gland genes of hibernating H. nipponia.

Hirudo nipponia is an important medicinal animal in China. Its salivary gland secretions contain a variety of protein bioactive substances. Investigations of its salivary glands are of great significance in the study of the medicinal value and mechanism of leech secretions. Illumina RNA-Seq technology was used to perform transcriptome sequencing of salivary gland tissue of H. nipponia under starvation (D30) and fed (D0) states. A total of 2,650 differentially expressed genes (DEGs) were screened. Using the label-free protein quantification technique and bioinformatics analysis, the expression of differentially expressed proteins (DEPs) in the salivary gland tissue of H. nipponia was compared. A total of 2,021 proteins were identified, among which 181 proteins were differentially expressed between the starvation and fed states, with 72 significantly upregulated and 109 significantly downregulated. The salivary glands of H. nipponia synthesized protein-based active substances after 30 days of starvation and adapted to the starvation environment by weakening respiratory activity and reducing metabolic activity to reduce energy expenditure. Energy was produced by glycolysis and the tricarboxylic acid cycle for the synthesis of substances such as antibiotics. This study combined transcriptome and proteome sequencing data to provide a data reference for an in-depth study of the regulatory mechanism of salivary gland secretions of H. nipponia under starvation stress by analyzing DEGs and DEPs.