Biology subjects

Jiang, X.-L.

Publications and source records attributed to Jiang, X.-L..

3 recordsLinked to original sources

bioRxiv2023

Evolutionary prediction for new echolocators

It was suggested over 60 years ago that echolocation is widespread in animals. Although echolocation has been found to evolve independently in several mammalian lineages, this hypothesis remains largely untested due to the difficulty of determining the presence of echolocation. To address this issue, we combined molecular convergence analyses from 190 high-quality mammalian genomes with machine learning to predict potential new mammalian echolocators. Our model predicted three promising lineages of echolocating mammals. Behavioral experiments confirmed that the gracile shrew mole (Uropsilus gracilis), the highest- ranking species among predicted echolocators, as well as almost all shrew moles (Uropsilinae), are capable of echolocation through the use of ultrasonic pulses. In contrast to most bats that use laryngeal echolocation, the characteristics of calls, the morphology of the stylohyal bone, and the results of tongue ligation experiments all suggest that shrew moles produce ultrasonic clicks with their tongues for echolocation. Finally, we estimated at least 20% of all living mammalian orders with echolocation ability, thus empirically supporting Griffins hypothesis that echolocation is widespread among animals. Our findings not only provide evidence that three novel lineages of echolocating mammals, but also demonstrate that phylogenetically replicated phenotypes can be predicted through genetic convergence. One sentence summaryShrew moles are capable of echolocation.

evolutionary biology↗

bioRxiv2022

VanRS and CroRS cross-talk revealed by coevolutionary modeling regulates antibiotic resistance in VanA-type vancomycin-resistant Enterococcus faecalis

Enterococcus faecalis is an opportunistic pathogen that can cause bacteremia and endocarditis. Previous studies have shown that concurrent treatment with cephalosporin and vancomycin antibiotics exhibit synergy in vancomycin-resistant E. faecalis to render the bacterium susceptible to antibiotic treatment whereas treatment with each antibiotic separately was not successful. Proteins responsible for mediating vancomycin and cephalosporin resistance are classified as two-component systems (TCS). TCS consist of a histidine kinase that phosphorylates a response regulator after environmental activation. These signaling networks have been shown to exhibit cross-talk interactions, and through direct coupling analysis, we identify encoded specificity between vancomycin resistance TCS, which are horizontally acquired, and cephalosporin resistance TCS, which are endogenous to E. faecalis. To verify cross-talk between these pathways is responsible for vancomycin and cephalosporin synergy, we use RNA-Seq to identify differentially expressed genes in VanA- and VanB-type vancomycin resistant enterococci after treatment with the cephalosporin antibiotic, ceftriaxone, and also with vancomycin. We find that cross-talk between VanSA and CroR in strain HIP11704 may be responsible for synergy, demonstrating that horizontally acquired TCS can have large impacts on pre-existing signaling networks. The presence of encoded specificity between exogenous TCS and endogenous TCS show that the systems co-evolve, and cross-talk between these systems may be exploited to engineer genetic elements that disrupt antibiotic resistance TCS pathways. Author SummaryBacteria may transmit genetic elements to other bacteria through the process known as horizontal gene transfer. In some enterococci, vancomycin resistance genes are acquired this way. Proteins encoded within the bacterial genome can interact with proteins acquired through horizontal gene transfer. The interaction that occurs between proteins VanSA and VanRA is known to mediate vancomycin antibiotic resistance in VanA-type vancomycin resistant enterococci (VRE), and the interaction between proteins CroS and CroR is an important pathway in cephalosporin antibiotic resistance. We show that the VanSA, which is obtained through horizontal gene transfer, inhibits CroR under treatment with antibiotics vancomycin and ceftriaxone. This interaction is responsible for the observed synergy between vancomycin and ceftriaxone in VanA-type VREs. These findings demonstrate how horizontally acquired genes may produce proteins that interrupt known protein interactions, including antibiotic resistance signaling pathways in bacteria. Furthermore, the specific mechanism found for VanA-type VREs provides a basis for engineering of horizontally acquired proteins that disrupt antibiotic resistance pathways.

microbiology↗

bioRxiv2017

Cryptic phylogeographic history sheds light on the generation of species diversity in sky-island mountains

Biodiversity hotspots should be given high priority for conservation under the situation of global climate change. The sky islands in southwestern China are characterized by extraordinarily high species diversity and are among one of the worlds top biodiversity hotspots. However, neither the actual species diversity in this region or mechanisms generating this diversity are well explored. Here, we report on the phylogeographic analysis of the long-tailed mole (Scaptonyx fusicaudus), a semi-fossorial mammal that inhabits the montane cool forests across the Chinese sky islands and is considered to represent one species divided into two subspecies. Analyses using DNA sequence data from one mitochondrial and six nuclear genes revealed that populations inhabiting different mountains exhibited exceptionally strong geographic structure. The lowlands and large rivers act as \"soft\" and \"hard\" barriers to dispersal, respectively, isolating evolutionary lineages for up to 11 million years. Our results suggest that the mountain ranges act as interglacial refugia buffering populations from climate fluctuations, further facilitating allopatric diversification. Strikingly, species delimitation analyses suggests that the long-tailed mole may comprise 18 operational taxonomic units and 17 putative species. Our results suggest that for low-vagility species, the complex topography of the Chinese sky islands has shaped genetic diversity and structure and promoted exceptional diversification through a combination of eco-environmental stability as well as geographic fragmentation. The patterns observed in S. fusicaudus may be representative for other cold- adapted species, reflecting the generation of mammalian faunal diversity in the sky-island mountains of southwestern China.

zoology↗