北京地区四个豹猫亚种群肠道菌群的组成

野生动物的肠道微生物组成受食物资源和遗传属性的影响较大,为了解北京地区小型猫科动物肠道菌群组成特点及其影响因素,本研究通过扩增细菌16S rRNA的V3‒V4高变区进行高通量测序,对云蒙山、云峰山、松山、百花山4个区域的豹猫(Prionailurus bengalensis)亚种群进行肠道菌群组成分析。结果表明,在门水平上,豹猫的肠道优势菌群主要由厚壁菌门(相对多度52.40%)、变形菌门(25.18%)、放线菌门(9.07%)、拟杆菌门(8.17%)和梭杆菌门(4.74%)组成。在属水平上,相对多度最高的前5个属为假单胞菌属(Pseudomonas,13.37%)、布劳特氏菌属(Blautia,11.20%)、梭菌属(Clostridium_sensu_stricto_1,9.10%)、消化梭菌属(Peptoclostridium,8.62%)、乳杆菌属(Lactobacillus,6.08%),共约占总多度的50%。各区域豹猫亚种群的肠道菌群β多样性不存在显著差异,松山区域的ACE指数和Chao 1指数与云蒙山和云峰山存在显著差异。鉴于松山亚种群的遗传结构与其他区域有所不同,而4个区域的气候类型和豹猫食物构成相似性高,推测该亚种群的肠道菌群主要受遗传结构分化的影响,对此还需进一步研究。

Evolution of the chloroplast division machinery

Chloroplasts are photosynthetic organelles derived from endosymbiotic cyanobacteria during evolution.Dramatic changes occurred during the process of the formation and evolution of chloroplasts,including the large-scale gene transfer from chloroplast to nucleus.However,there are still many essential characters remaining.For the chloroplast division machinery,FtsZ proteins,Ftn2,SulA and part of the division site positioning system-MinD and MinE are still conserved.New or at least partially new proteins,such as FtsZ family proteins FtsZ1 and ARC3,ARC6H,ARC5,PDV1,PDV2 and MCD1,were introduced for the division of chloroplasts during evolution.Some bacterial cell division proteins,such as FtsA,MreB,Ftn6,FtsW and FtsI,probably lost their function or were gradually lost.Thus,the chloroplast division machinery is a dynamically evolving structure with both conservation and innovation.