In their natural habitats,bacteria thrive in densely populated environments(such as soil and the human gut)and compete with other microorganisms for ecological niches[1].Secretion systems enable bacteria to export pro...In their natural habitats,bacteria thrive in densely populated environments(such as soil and the human gut)and compete with other microorganisms for ecological niches[1].Secretion systems enable bacteria to export proteins into their surroundings and play key roles in interbacterial competition,development,nutrient acquisition,and virulence[2–4].Type VII secretion system b(T7SSb)has been primarily identified in low-G+C Firmicutes,which exhibit significant inter-and intraspecies heterogeneity in secreting putative toxin effectors.展开更多
文摘鯻科鱼类是广泛分布于印度-西太平洋常见经济鱼类,由于不同物种间外部形态较为相似,且种内有一定变化,物种鉴定存在一定困难。为明确中国鯻科鱼类的分类地位,对中国鯻科鱼类进行了详细的形态计测,并测定了3属共62 ind鱼类COI基因5’端652 bp COI序列,结合Gen Bank中三线鯻3个地点9条序列,发现我国除已报道的3属4种鯻科外,新发现目前仅见于广东的三线鯻,是中国鯻科鱼类的新纪录。在基于Kimura-2-paramter的邻接树上,5种鯻科鱼类均独立成支。种间遗传距离18.34%(15.9%~20.1%)约为种内遗传距离0.72%(0.1%~2.7%)的24.93倍,形成较为明显的条码间隙。三线鯻可按地理来源分为西太平洋和印度洋-地中海2个谱系,具有明显的谱系结构和地理结构;谱系间遗传距离为5%(0.2%~5.6%)为谱系内遗传距离0.85%[谱系A为0.6%(0~1.7%),谱系B为1.1%(0.2%~5.6%)]的5.88倍,谱系间与谱系内遗传距离倍数略低于大多数物种(种间是种内遗传距离10倍),但远高于其种内遗传距离一般小于2%的范围。同时,鯻科内种间在形态上存在诸如侧面体型细长扁平或肥厚、臀鳍是否带隐约散点斑纹、背鳍硬棘的Ⅲ–VI或Ⅶ-Ⅷ间是否有黑色斑点、头部至背鳍前端略带蓝灰或黄绿光泽、身体背部浅灰或浅棕色等区别。分子和形态差异表明,印度-西太平洋分布的三线鯻可能是2个亚种乃至2个种。由于本文分析的三线鯻的数量和地理范围有限,其准确的分类地位仍需要更多的形态计测和核基因数据等研究加以确定。
基金supported by the National Natural Science Foundation of China(82225028,82172287,32171265,31900879,and 32370185)the National Key Research and Development Program of China(2021YFC2301403)+1 种基金the high-level personnel introduction grant form Fujian Normal University(Z0210509)the Natural Science Foundation of Fujian Province(2023J011797 and 2024J010025).
文摘In their natural habitats,bacteria thrive in densely populated environments(such as soil and the human gut)and compete with other microorganisms for ecological niches[1].Secretion systems enable bacteria to export proteins into their surroundings and play key roles in interbacterial competition,development,nutrient acquisition,and virulence[2–4].Type VII secretion system b(T7SSb)has been primarily identified in low-G+C Firmicutes,which exhibit significant inter-and intraspecies heterogeneity in secreting putative toxin effectors.
