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Background The majority of bat species have developed remarkable echolocation ability, especially for the laryngeally echolocating bats along with high-frequency hearing. Adaptive evolution has been widely detected for the cochleae in the laryngeally echolocating bats, however, limited understanding for the brain which is the central to echolocation signal processing in the auditory perception system, the laryngeally echolocating bats brain may also undergo adaptive changes. Result In order to uncover the molecular adaptations related with high-frequency hearing in the brain of laryngeally echolocating bats, the genes expressed in the brain of Rhinolophus ferrumequinum (CF bat) and Myotis pilosus (FM bat) were both detected and also compared. A total of 346,891 genes were detected and the signal transduction mechanisms were annotated by the most abundant genes, followed by the transcription. In hence, there were 3,088 DEGs were found between the two bat brains, with 1,426 highly expressed in the brain of R. ferrumequinum , which were significantly enriched in the neuron and neurodevelopmental processes. Moreover, we found a key candidate hearing gene, ADCY1 , playing an important role in the R. ferrumequinum brain and undergoing adaptive evolution in CF bats. Conclusions Our study provides a new insight to the molecular bases of high-frequency hearing in two laryngeally echolocating bats brain and revealed different nervous system activities during auditory perception in the brain of CF bats.

ABSTRACT White‐nose syndrome (WNS), caused by the fungus Pseudogymnoascus destructans (Pd), has led to significant mortality and species endangerment in North America. Bats in eastern China, however, carry low loads of Pd and do not exhibit disease, suggesting natural resistance. To explore potential defenses, we isolated and screened antagonistic bacteria from the wing membranes of Rhinolophus ferrumequinum for their ability to inhibit Pd growth. We employed the plate delineation isolation method to obtain 74 single strains, which were then screened for antagonistic effects through contact and non‐contact inhibition experiments. A total of 18 antagonistic strains were isolated. After sequencing and comparison with the NCBI database, we identified eight known species and three unidentified species of antagonistic bacteria: Pseudomonas carnis, Buttiauxella ferragutiae, Paraburkholderia fungorum, Arthrobacter rhombi, Serratia liquefaciens, Paeniglutamicibacter gangotriensis, Brevibacterium aurantiacum, Acinetobacter lactucae, Pseudomonas sp., Brevibacterium sp., and Acinetobacter sp. Seventeen isolated strains showed varying degrees of inhibition by contact, while five species, including P. carnis, B. ferragutiae, S. liquefaciens, P. gangotriensis, and Brevibacterium sp., also inhibited Pd via non‐contact mode. We utilized solid‐phase microextraction coupled with GC–MS to obtain approximately 20 volatile compounds, all of which exhibited inhibitory effects on the growth of Pd, including ketones, aldehydes, and sulfur ethers. Notably, 5 ppm of 1‐undecene, dimethyl trisulphide, and 2‐nonanone each independently inhibited Pd growth. These findings suggest that the antagonistic strains and their VOCs might help protect bats from WNS. Understanding the interactions between Pd and skin flora, along with their VOCs, may be crucial in mitigating bats' vulnerability to WNS and developing effective mitigation strategies in the future. In this study, 18 antagonistic bacteria inhibiting Pd growth were isolated from R. ferrumequinum skin. Of these, 17 exhibited contact inhibition, while 7 showed non‐contact inhibition, and they were identified as belonging to 12 taxa. Among those exhibiting non‐contact inhibition, B. ferragutiae, S. liquefaciens, and P. gangotriensis were most effective. For contact inhibition, P. carnis, A. rhombi, S. liquefaciens, and an unidentified Pseudomonas species were most effective. Approximately 20 VOCs were isolated, with 5 ppm of 1‐undecene, dimethyl trisulfide, and 2‐nonanone showing significantly inhibitory effects on Pd. This research highlights the skin microbiota as a crucial defense against fungal pathogens and may offer new approaches and microbial sources for controlling Pd spread.

Background In genus Rhinolophus , species in the Rhinolophus philippinensis and R. macrotis groups are unique because the horseshoe bats in these group have relatively low echolocation frequencies and flight speeds compared with other horseshoe bats with similar body size. The different characteristics among bat species suggest particular evolutionary processes may have occurred in this genus. To study the adaptive evidence in the mitochondrial genomes (mitogenomes) of rhinolophids, especially the mitogenomes of the species with low echolocation frequencies, we sequenced eight mitogenomes and used them for comparative studies of molecular phylogeny and adaptive evolution. Results Phylogenetic analysis using whole mitogenome sequences produced robust results and provided phylogenetic signals that were better than those obtained using single genes. The results supported the recent establishment of the separate macrotis group. The signals of adaptive evolution discovered in the Rhinolophus species were tested for some of the codons in two genes ( ND2 and ND6 ) that encode NADH dehydrogenases in oxidative phosphorylation system complex I. These genes have a background of widespread purifying selection. Signals of relaxed purifying selection and positive selection were found in ND2 and ND6 , respectively, based on codon models and physicochemical profiles of amino acid replacements. However, no pronounced overlap was found for non-synonymous sites in the mitogenomes of all the species with low echolocation frequencies. A signal of positive selection for ND5 was found in the branch-site model when R. philippinensis was set as the foreground branch. Conclusions The mitogenomes provided robust phylogenetic signals that were much more informative than the signals obtained using single mitochondrial genes. Two mitochondrial genes that encoding proteins in the oxidative phosphorylation system showed some evidence of adaptive evolution in genus Rhinolophus and the positive selection signals were tested for ND5 in R. philippinensis . These results indicate that mitochondrial protein-coding genes were targets of adaptive evolution during the evolution of Rhinolophus species, which might have contributed to a diverse range of acoustic adaptations in this genus.

Heterogeneous pathogenic stress can shape major histocompatibility complex (MHC) diversity by influencing the functional plasticity of the immune response. Therefore, MHC diversity could reflect environmental stress, demonstrating its importance in uncovering the mechanisms of adaptive genetic variation. In this study, we combined neutral microsatellite loci, an immune‐related MHC II‐DRB locus, and climatic factors to unravel the mechanisms affecting the diversity and genetic differentiation of MHC genes in the greater horseshoe bat (Rhinolophus ferrumequinum), a species with a wide geographical distribution that has three distinct genetic lineages in China. First, increased genetic differentiation at the MHC locus among populations compared using microsatellites indicated diversifying selection. Second, the genetic differentiation of MHC and microsatellites were significantly correlated, suggesting that demographic processes exist. However, MHC genetic differentiation was significantly correlated with geographical distance among populations, even after controlling for the neutral markers, suggesting a major effect of selection. Third, although the MHC genetic differentiation was larger than that for microsatellites, there was no significant difference in the genetic differentiation between the two markers among genetic lineages, indicating the effect of balancing selection. Fourth, combined with climatic factors, MHC diversity and supertypes showed significant correlations with temperature and precipitation, but not with the phylogeographic structure of R. ferrumequinum, suggesting an effect of local adaptation driven by climate on MHC diversity. Moreover, the number of MHC supertypes varied between populations and lineages, suggesting regional characteristics and support for local adaptation. Taken together, the results of our study provide insights into the adaptive evolutionary driving forces at different geographic scales in R. ferrumequinum. In addition, climate factors may have played a vital role in driving adaptive evolution in this species.

Niche theory predicts that ecologically similar sympatric species should show differentiation in at least one of the main niche dimensions (time, space, and/or food). Here, we combined observations of breeding timing, nest site selection, and diet (the latter determined using DNA metabarcoding) to analyze the niche overlap and differentiation between two sympatric secondary cavity‐nesting birds, the Japanese Tit Parus minor and the Yellow‐rumped Flycatcher Ficedula zanthopygia. The results showed that (1) there were significant differences in the first egg laying date, length of the egg laying period, incubation date, and hatching date between tits and flycatchers, and the breeding time of flycatchers peaked later (about 30 days) than that of tits; (2) the two species had a large overlap in nest site selection, although the canopy coverage and shrub density of flycatchers were significantly higher than those of tits; and (3) the niche overlap in diet was minimal, with both species heavily relying on Lepidoptera (39.6% and 63.7% for tits and flycatchers, respectively), but with flycatchers consuming significantly higher percentages of Lepidoptera, Diptera, and Coleoptera than tits. The results indicate that these two sympatric secondary cavity‐nesting species have significant niche differentiation in breeding time and diet, but little differentiation in nest site selection. Two sympatric secondary cavity‐nesting bird species have significant niche differentiation in breeding time and diet.

Background Mesenchymal stem cells (MSCs) hold a great promise for cell-based therapy in the field of regenerative medicine. In this study, we aimed to evaluate the safety and efficacy of intravenous infusion of human umbilical cord-derived MSCs (HUC-MSCs) in patients with aging frailty. Methods In this randomized, double-blind, placebo-controlled trial, participants diagnosed with aging frailty were randomly assigned to receive intravenous administrations of HUC-MSCs or placebo. All of serious adverse events and AEs were monitored to evaluate the safety of treatment during the 6-month follow-up. The primary efficacy endpoint was alteration of physical component scores (PCS) of SF-36 qualities of life at 6 months. The secondary outcomes including physical performance tests and pro-inflammatory cytokines, were also observed and compared at each follow-up visits. All evaluations were performed at 1 week, 1, 2, 3 and 6 months following the first intravenous infusion of HUC-MSCs. Results In the MSCs group, significant improvements in PCS of SF-36 were observed from first post-treatment visit and sustained throughout the follow-up period, with greater changes compared to the placebo group ( p  = 0.042). EQ-VAS scores of MSCs group improved significantly at 2 month ( p  = 0.023) and continued until the end of the 6-month visit ( p  = 0.002) in comparison to the placebo group. The timed up and go (TUG) physical performance test revealed significant group difference and showed continual enhancements over 6 months ( p  < 0.05). MSC transplantation improved the function of 4-m walking test (4MWT) compared with the placebo group with a decrease of 2.05 s at 6 months of follow-up ( p  = 0.21). The measurement of grip strength revealed group difference with MSCs group demonstrating better performance, particularly at 6 months ( p  = 0.002). Inflammatory cytokines (TNF-α, IL-17) exhibited declines in MSCs group at 6 months compared to the placebo group ( p  = 0.034 and 0.033, respectively). There was no difference of incidence of AEs between the two groups. Conclusion Intravenous transplantation of HUC-MSCs is a safe and effective therapeutic approach on aging frailty. The positive outcomes observed in improving quality of life, physical performance, and reducing chronic inflammation, suggest that HUC-MSC therapy may be a promising potential treatment option for aging frailty. Trial Registration : Clinicaltrial.gov; NCT04314011; https://clinicaltrials.gov/ct2/show/NCT04314011 .

Predicting species' fates following the introduction of a novel pathogen is a significant and growing problem in conservation. Comparing disease dynamics between introduced and endemic regions can offer insight into which naive hosts will persist or go extinct, with disease acting as a filter on host communities. We examined four hypothesized mechanisms for host–pathogen persistence by comparing host infection patterns and environmental reservoirs for Pseudogymnoascus destructans (the causative agent of white-nose syndrome) in Asia, an endemic region, and North America, where the pathogen has recently invaded. Although colony sizes of bats and hibernacula temperatures were very similar, both infection prevalence and fungal loads were much lower on bats and in the environment in Asia than North America. These results indicate that transmission intensity and pathogen growth are lower in Asia, likely due to higher host resistance to pathogen growth in this endemic region, and not due to host tolerance, lower transmission due to smaller populations, or lower environmentally driven pathogen growth rate. Disease filtering also appears to be favouring initially resistant species in North America. More broadly, determining the mechanisms allowing species persistence in endemic regions can help identify species at greater risk of extinction in introduced regions, and determine the consequences for disease dynamics and host–pathogen coevolution.

ABSTRACT Studies on foraging site selection during the breeding period of waterbirds can identify key ecological factors, providing a scientific foundation for their conservation and habitat management. The Scaly‐sided Merganser (Mergus squamatus) is a globally endangered species and serves as an indicator species in submontane valleys. However, research on the key ecological factors influencing foraging site selection at different breeding stages remains limited. In this study, ecological variables were collected from 226 sites in the Changbai Mountains, Northeast China, including 115 foraging sites and 111 control sites, across various breeding stages of M. squamatus. The analysis focused on foraging site selection during the egg‐laying, incubation, and brooding periods of M. squamatus. The results indicated that concealment (C) was the key ecological factor influencing foraging site selection for M. squamatus during the egg‐laying period. During incubation, the distance to potential nesting sites (DPNS) and the distance from buildings (DB) emerged as significant factors. In contrast, the brooding period highlighted the importance of the borderland ratio (BR) and heartland ratio (HR). These variations in key ecological factors at different breeding stages are likely due to the distinct physiological and behavioral requirements of M. squamatus at each stage. Key ecological factors influencing the selection of foraging sites by the Scaly‐Sided Merganser across different breeding stages.

Summary White‐nose syndrome, a disease that is caused by the psychrophilic fungus Pseudogymnoascus destructans, has threatened several North America bat species with extinction. Recent studies have shown that East Asian bats are infected with P. destructans but show greatly reduced infections. While several factors have been found to contribute to these reduced infections, the role of specific microbes in limiting P. destructans growth remains unexplored. We isolated three bacterial strains with the ability to inhibit P. destructans, namely, Pseudomonas yamanorum GZD14026, Pseudomonas brenneri XRD11711 and Pseudomonas fragi GZD14479, from bats in China. Pseudomonas yamanorum, with the highest inhibition score, was selected to extract antifungal active substance. Combining mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy analyses, we identified the active compound inhibiting P. destructans as phenazine‐1‐carboxylic acid (PCA), and the minimal inhibitory concentration (MIC) was 50.12 μg ml−1. Whole genome sequencing also revealed the existence of PCA biosynthesis gene clusters. Gas chromatography‐mass spectrometry (GC‐MS) analysis identified volatile organic compounds. The results indicated that 10 ppm octanoic acid, 100 ppm 3‐tert‐butyl‐4‐hydroxyanisole (isoprenol) and 100 ppm 3‐methyl‐3‐buten‐1‐ol (BHA) inhibited the growth of P. destructans. These results support that bacteria may play a role in limiting the growth of P. destructans on bats. White‐nose syndrome, a disease that is caused by the psychrophilic fungus Pseudogymnoascus destructans, has threatened several North America bat species with extinction. We isolated three bacterial strains with the ability to inhibit P. destructans, namely, Pseudomonas yamanorum GZD14026, Pseudomonas brenneri XRD11711 and Pseudomonas fragi GZD14479, from bats in China. We identified the active compound inhibiting P. destructans as phenazine‐1‐carboxylic acid (PCA), octanoic acid, 3‐tert‐butyl‐4‐hydroxyanisole, 3‐methyl‐3‐buten‐1‐ol from Pseudomonas yamanorum GZD14026.

Globalization has facilitated the worldwide movement and introduction of pathogens, but epizoological reconstructions of these invasions are often hindered by limited sampling and insufficient genetic resolution among isolates. Pseudogymnoascus destructans , a fungal pathogen causing the epizootic of white-nose syndrome in North American bats, has exhibited few genetic polymorphisms in previous studies, presenting challenges for both epizoological tracking of the spread of this fungus and for determining its evolutionary history. We used single nucleotide polymorphisms (SNPs) from whole-genome sequencing and microsatellites to construct high-resolution phylogenies of P. destructans . Shallow genetic diversity and the lack of geographic structuring among North American isolates support a recent introduction followed by expansion via clonal reproduction across the epizootic zone. Moreover, the genetic relationships of isolates within North America suggest widespread mixing and long-distance movement of the fungus. Genetic diversity among isolates of P. destructans from Europe was substantially higher than in those from North America. However, genetic distance between the North American isolates and any given European isolate was similar to the distance between the individual European isolates. In contrast, the isolates we examined from Asia were highly divergent from both European and North American isolates. Although the definitive source for introduction of the North American population has not been conclusively identified, our data support the origin of the North American invasion by P. destructans from Europe rather than Asia. IMPORTANCE This phylogenetic study of the bat white-nose syndrome agent, P. destructans , uses genomics to elucidate evolutionary relationships among populations of the fungal pathogen to understand the epizoology of this biological invasion. We analyze hypervariable and abundant genetic characters (microsatellites and genomic SNPs, respectively) to reveal previously uncharacterized diversity among populations of the pathogen from North America and Eurasia. We present new evidence supporting recent introduction of the fungus to North America from a diverse Eurasian population, with limited increase in genetic variation in North America since that introduction. This phylogenetic study of the bat white-nose syndrome agent, P. destructans , uses genomics to elucidate evolutionary relationships among populations of the fungal pathogen to understand the epizoology of this biological invasion. We analyze hypervariable and abundant genetic characters (microsatellites and genomic SNPs, respectively) to reveal previously uncharacterized diversity among populations of the pathogen from North America and Eurasia. We present new evidence supporting recent introduction of the fungus to North America from a diverse Eurasian population, with limited increase in genetic variation in North America since that introduction.