Hunan Agricultural Products (China)

Vibrio alginolyticus is a foodborne pathogen commonly found in seafood and freshwater products, causing human illness through the consumption of tainted seafood. Small non-coding RNAs (sRNAs) take effect on the stability and translation of their target mRNAs by base-pairing, thereby quickly altering bacterial physiology and pathogenicity at the post-transcriptional level. This work constructed a label-free in-frame deletion mutant and a complement strain of micX, a cell-density-associated sRNA in V. alginolyticus. The ΔmicX mutant exhibited reduced growth and a reduction in the synthesis of exopolysaccharides, biofilm, and alkaline serine protease. A TMT-based quantitative proteomic analysis comparing ΔmicX with the wild-type strain identified 900 differentially expressed proteins, comprising 376 that were upregulated and 524 that were downregulated. The upregulated proteins are primarily associated with porin activity, transmembrane signaling receptor function, and the two-component system. The downregulated proteins are mainly engaged in processes including biofilm formation, cellular communication, and transmembrane transport activity. Of note, the expression levels of proteins involved in the type VI secretion system, exopolysaccharide synthesis, mannose-sensitive hemagglutinin type IV pili (MSHA), and biofilm formation were significantly reduced in the absence of micX. Furthermore, the expression levels of proteins associated with quorum sensing (particularly LuxR and AphA) changed significantly in the ΔmicX vs. WT comparison. These findings strengthened comprehension of the novel sRNA regulatory network and established a theoretical foundation for additional investigations into the virulence of V. alginolyticus.

Abstract Aspidogastrea is the most likely candidate for the sister group to all other Trematoda (“basal” radiation). However, genomic resources for this lineage remain scarce, so the evolutionary history of trematodes remains only partially understood. We sequenced the mitochondrial genomes (mitogenomes) of two aspidogastreans, Aspidogaster ijimai and Aspidogaster conchicola, and combined them with 51 available Trematoda mitogenomes to address methodological uncertainties in phylogenetic reconstruction and assess whether mitogenomic data also support Aspidogastrea as the “basal” radiation. Through a systematic evaluation of dataset types (nucleotide/amino acid), outgroups (Monogenea/Cestoda), partitioned/non-partitioned datasets, evolutionary models (assuming sequence homogeneity/heterogeneity), and different multi-locus sequence analyses methods (concatenation/multispecies coalescent), we demonstrated that: (1) some outgroup choices caused long-branch attraction artefacts; (2) partitioned datasets improved the performance of standard (“homogeneous”) models; (3) multispecies coalescent method was heavily influenced by outgroup effects; (4) CAT-GTR model was the most robust to systematic errors. CAT-GTR model consistently produced phylogenies of Trematoda that were congruent with the nuclear genomic (nDNA) topology at major nodes (deep phylogenetic level), with Aspidogastrea as the “basal” radiation, and all major lineages (order and suborder) monophyletic, aside from the paraphyletic suborder Xiphidiata. We further used the CAT-GTR mitogenomic topology and the nDNA topology to establish a time-calibrated phylogeny of Trematoda. The two datasets placed the Aspidogastrea-Digenea divergence at ∼246 - 360 Ma and ∼271 - 446 Ma, and the Diplostomida-Plagiorchiida divergence at ∼216-306 Ma and ∼213-347 Ma, respectively.

Life-history plasticity allows fishes to exploit heterogeneous freshwater networks, and proactive habitat selection enhances their capacity to cope with climatic and human-induced stressors. Coilia brachygnathus, long regarded as a freshwater resident, nevertheless has a poorly understood habitat use and selection. We reconstructed habitat use of C. brachygnathus across the middle-lower Yangtze by coupling water 87Sr/86Sr baselines with otolith 87Sr/86Sr transects. We used 60 water samples, compiled published datasets, and measured additional water samples from the mainstem, major tributaries, and connected lakes. In situ 87Sr/86Sr profiles were smoothed with generalized additive models, revealing significant within-profile variation for all fish. Two modes emerged: (i) residents, whose otolith values remained within local water ranges, consistent with limited movement; and (ii) migrants, whose profiles departed from local baselines, indicating exchanges among lakes, tributaries, and the mainstem. Several fish captured at Anqing and Zhenjiang possess Poyang-like core signatures that declined to mainstem values, while bidirectional shifts were common in the Dongting-Xiang system. These results overturn the residency paradigm, demonstrate flexible partial migration, and indicate proactive habitat selection in the face of environmental change, thereby supporting management that maintains river-lake connectivity and quantifies lake contributions to mainstem stocks.

Simple SummaryUnderstanding how species coexist is essential for conserving biodiversity. This study investigates the spatio-temporal niche differentiation among three sympatric ungulates—alpine musk deer (Moschus chrysogaster), Chinese serow (Capricornis milneedwardsii), and tufted deer (Elaphodus cephalophus)—in Changdu, Tibet. Using data from 186 camera traps and species distribution models (SDMs), we analyzed their habitat preferences and daily activity rhythms. The results revealed distinct patterns: Tufted deer occupied smaller, fragmented forest habitats (total suitable area: 14,968 km2), while alpine musk deer (41,909 km2) and Chinese serow (36,954 km2) showed broader distributions with significant spatial overlap (26,869 km2). Temporally, tufted deer and alpine musk deer exhibited diurnal activity with peak overlaps (Δ = 0.88), whereas chinese serow was primarily nocturnal, reducing direct competition through temporal partitioning (Δ = 0.76–0.82; all p < 0.001). These findings underscore how spatial and temporal niche differentiation facilitates coexistence, providing a scientific basis for targeted conservation strategies in high-altitude ecosystems.Knowledge of the mechanisms of species coexistence is crucial for biodiversity conservation. The tufted deer (Elaphodus cephalophus), alpine musk deer (Moschus chrysogaster), and Chinese serow (Capricornis milneedwardsii) are all found in alpine ecosystems in Tibet, China. To investigate how these sympatric species achieve stable coexistence, we compared species distribution models and diurnal activity rhythms to analyze their spatial and temporal niche characteristics based on data collected from 186 camera traps set in Changdu prefecture. The results indicate he following: (1) In Changdu, the total area of suitable habitats for tufted deer, alpine musk deer and Chinese serow are 14,968 km2, 41,909 km2, and 36,954 km2, respectively. These areas represent approximately 13.62%, 38.14%, and 33.63% of the study area, respectively. (2) The total overlapping area of suitable habitats between tufted deer and alpine musk deer is 5102 km2. The total overlapping area of suitable habitats between tufted deer and Chinese serow is 6483 km2. Additionally, the total overlapping area of suitable habitats between alpine musk deer and Chinese serow amounts to 26,869 km2. (3) The overlap index for daily activity rhythms between tufted deer and alpine musk deer is 0.88—this difference is statistically significant (p < 0.001). Similarly, the overlap index for daily activity rhythms between tufted deer and Chinese serow is 0.82—also significantly different (p < 0.001). Lastly, the overlap index for daily activity rhythms between alpine musk deer and Chinese serow is 0.76—again showing a significant difference (p < 0.001). The results provide valuable insight into conservation strategies aimed at preserving populations and habitats of tufted deer, alpine musk deer, and Chinese serow while contributing to a deeper understanding of resource partitioning mechanisms as well as population dynamics among coexisting species.