Project description:Coreius guichenoti, mainly distributed in upstream regions of the Yangtze River China, is currently on the brink of extinction and listed as national secondary protected animal. In this study, we aimed to obtain the chromosome-level genome of C. guichenoti using PacBio and Hi-C techniques. According to the PacBio sequencing, C. guichenoti genome was successfully assembled to 1100.1 Mb size, with a Contig N50 size of 25.0 Mb, and containing 731.0 Mb of repeats. Hi-C sequencing data was utilized for chromosome assembly and 25 chromosome sequences were ultimately yielded, with a total length of 1076.8 Mb. Moreover, a total of 22,506 protein-coding genes were predicted with average intron length of 2293 bp. Evolutionary analysis and divergence time prediction revealed that C. guichenoti was closely related to C. heterodon and they phylogenetically diverged from common ancestor ~20.7 million years ago (Mya), following the separation of Cyprinidae at 28.3 Mya. In the future, the utilization of comparative genomics research is important in elucidating the molecular mechanisms of Ichthyophthirius disease and ensuring the conservation of biological resources.
Project description:The wild population resources of Coreius guichenoti have sharply declined in recent decades, and any negative factors may have a significant impact on their survival. In this study, the enzymatic stress responses of C. guichenoti to 25 and 48 μm polyethylene fragments were explored for the first time. This was achieved by evaluating the changes in physiological and biochemical indicators of the species in response to the environmental stimuli of microplastics. In this study, we observed an early stress response in the external tissues of C. guichenoti following exposure to microplastics. The TP content in skin and muscle and the MDA content in skin, gill and muscle initially showed a significant increase. The skin, gill, and muscle exhibited greater stress responses to M5 particles, whereas M3 particles caused a greater response in the intestine and especially the liver. After the removal of microplastic exposure, the stress state of the C. guichenoti would be alleviated in a short period, but it could not fully recover to the pre-exposure level. In summary, microplastics pose a significant threat to C. guichenoti. While their negative effects can be alleviated by the removal of microplastics exposure, full recovery does not occur in a short period. Continuous monitoring of microplastics in natural waters and targeted aquatic ecological restoration are essential to ensure the normal growth and reproduction of the wild population of C. guichenoti.
Project description:High-throughput sequencing was applied to compare the intestinal microbiota in largemouth bronze gudgeon either healthy or affected by furunculosis. Proteobacteria, Actinobacteria, Tenericutes, Firmicutes and Bacteroidetes were detected as the predominant bacterial phyla in the gut of both diseased and healthy fish. The abundance of Proteobacteria differed significantly between the two groups of fish, mainly due to the overwhelming prevalence of Aeromonas in the diseased fish (81% ± 17%), while the genus was unevenly spread among the apparently healthy fish (33% ± 33%). The bacterial diversity in the intestine of diseased fish was markedly lower than in healthy fish. Analysis revealed the significant dissimilarity between the gut microbiota of diseased and healthy fish. The bacterial profiles in the gut were further characterized with the 28 phylotypes that were shared by the two groups. In diseased fish, two shared OTUs (OTU0001 and OTU0013) were closely related to Aeromonas salmonicida, their total proportion exceeding 70% of the sequences in diseased fish, while averaging 5.2% ± 4.6% in the healthy fish. This result suggested the presence of healthy carriers of pathogenic A. salmonicida among the farmed fish, and the gut appeared as a probable infection source for furunculosis in largemouth bronze gudgeon.