人工饲喂对长尾仓鼠肠道菌群组成的影响

食物变化是引起小型哺乳动物肠道菌群改变的关键因素。野生动物由野外转至室内饲养会经历剧烈的生活方式变化,而目前对人工饲喂驱动其肠道微生物群落结构的演替过程还不完全了解。为明确人工饲喂对小型哺乳动物肠道菌群组成的影响,于2022年夏季(7—9月)在山西省吕梁市离石区(LS)、临汾市隰县(XX)、晋中市左权县(ZQ) 3个地区应用笼捕法捕获长尾仓鼠(Cricetulus longicaudatus)活体,基于16S rDNA测序技术分析不同生态环境中其肠道菌群的差异,并探究相同人工饲喂条件下长尾仓鼠肠道菌群的演替过程。结果表明：长尾仓鼠肠道菌群在野外环境中,XX和ZQ种群的厚壁菌门显著富集,LS种群的拟杆菌门显著富集,肠单胞球菌属(Intestinimonas)为3个种群的共有优势属。相同人工饲喂35 d后,拟杆菌门在3个种群显著富集且相对丰度趋于一致,ZQ种群Muribaculacea的相对丰度为48.85%,显著高于野外环境。本研究说明不同生态环境中长尾仓鼠肠道菌群具有差异性。经长期相同人工饲喂后,其肠道菌群的相似性显著增加,说明饮食变化对长尾仓鼠肠道菌群多样性及群落组成具有较大影响,而...     

峨眉山与黄山藏酋猴肠道菌群组成的比较

峨眉山和黄山都是我国著名的藏酋猴Macaca thibetana生态旅游地,对两地藏酋猴肠道微生物群落结构的比较研究,有助于了解不同生境、不同旅游管理方式对野生灵长类动物的影响。本研究对峨眉山藏酋猴M. t.thibetana肠道微生物16S rRNA基因进行测序,并与黄山藏酋猴M. t. huangshanensis肠道微生物的群落结构进行了比较。结果显示,两地藏酋猴肠道菌群有大量共有的可操作分类单元,而群落组成和多样性方面存在较大差异。峨眉山藏酋猴肠道菌群的优势门类为厚壁菌门Firmicutes(69. 04%±11. 81%)、拟杆菌门Bacteroidetes(21. 59%±10. 05%)和放线菌门Actinobacteria (2. 73%±2. 17%);黄山藏酋猴为厚壁菌门(46. 34%±8. 15%)、拟杆菌门(36. 75%±6. 38%)和变形菌门Proteobacteria(14. 91%±8. 06%)。在属级水平上,峨眉山藏酋猴肠道丰度最高的为颤螺菌属Oscillospira(23. 49%±16. 63%),黄山藏酋猴为普氏菌属Prevotella(36. 35%±9. 15%)。在群落多样性方面,黄山藏酋猴α多样性指数显著低于峨眉山,且两者的菌群结构也产生了显著分化。PICRUSt功能富集分析显示,峨眉山藏酋猴在脂类代谢、外源化学物的降解与代谢等通路显著富集,而黄山藏酋猴在多糖的合成与代谢等通路显著富集。研究还发现峨眉山藏酋猴肠道存在一定丰度的传染性致病菌,这可能与峨眉山的生态旅游有关。     

实验室饲养和野外生存条件下东方田鼠肠道菌群的多样性

目的探讨实验室饲养和野外生存条件下东方田鼠肠道菌群的分布和差异。方法应用高通量测序技术测定实验室饲养和野外捕捉东方田鼠的肠道细菌16S rDNA-V4-V5区序列,统计操作分类单元(OTUs)数量,分析菌群物种丰度、分布及差异性。结果稀疏曲线表明取样数量合理,测序充分。在门水平,实验室饲养和野外生存的肠道菌群分布和占比基本相似,实验组有1个独有的门,即黏胶球形菌门(Lentisphaerae),野生组有3个独有的门,分别是梭杆菌门(Fusobacteria)、奇古菌门(Thaumarchaeota)和未分类的门,丰度差异最大的为软壁菌门(Tenericutes)。在属水平,野外东方田鼠肠道细菌较实验室饲养的丰富,丰度差异最大的为瘤胃球菌属(Ruminococcus)。结论获得了实验室饲养和野外生存条件下东方田鼠肠道菌群结构和差异性,进一步充实了东方田鼠基础生物学数据。     

高寒草甸鼠兔活动对土壤微生物群落特征的影响

高原鼠兔活动严重影响了高寒草甸生态系统的多样性及稳定性, 土壤微生物对环境变化高度敏感, 其群落特征受到了高原草甸鼠兔活动的显著影响。为探究鼠兔活动对土壤微生物群落结构及多样性的影响, 本实验以青海湖高寒草甸鼠兔活动干扰下的土壤微生物为研究对象, 基于细菌16s rRNA进行高通量测序。不同处理下的土壤细菌的优势菌群相似, 主要包括变形菌门和酸杆菌门。与自然状态下的高寒草甸相比, 鼠兔活动下的土壤细菌群落丰富度显著增加, 多样性指数显著降低 (P < 0.05)。鼠兔活动显著影响了土壤细菌的群落结构 (P < 0.05), 对照与鼠兔活动分组间存在104个差异菌群, 鼠兔活动下的亚表层土壤 (10—20 cm) 仅有3个菌群相对丰度显著升高, 鼠兔活动下的表层土壤 (0—10 cm) 则存在52个差异菌群。FAPROTAX预测分析表明, 土壤细菌群落功能基团多为碳氮代谢相关的功能基团, 另有部分与无氧呼吸途径及人类疾病有关。总体而言, 鼠兔活动显著影响了高寒草甸土壤细菌的群落结构及多样性特征, 且表层土壤的细菌群落对鼠兔活动的响应更为明显。     

椰心叶甲、椰子织蛾肠道菌群多样性分析

[目的] 椰心叶甲、椰子织蛾同属棕榈科食叶性入侵害虫,两者同时取食棕榈科植物却无明显竞争作用,本文通过分子生物学手段对两者的肠道菌群组成、肠道代谢通路进行比对,以此探讨两者食性之间相关性。[方法] 以16S rRNA菌群分析等预测手段对两者肠道微生物群落、代谢通路等进行差异分析。[结果] 椰心叶甲体内变形菌门群落丰度显著高于椰子织蛾,椰子织蛾体内蓝菌门、放线菌门、酸杆菌门、疣微菌门等菌群丰度显著高于椰心叶甲;椰心叶甲体内膦酸酯和亚膦酸盐代谢、N-聚糖合成等肠道代谢通路显著强于椰子织蛾,而椰子织蛾肠道中酮体的合成和降解、维生素B6代谢、核黄素代谢、黄酮和黄酮醇生物合成等代谢通路显著强于椰心叶甲。[结论] 椰子织蛾体内相对较高的酸杆菌门丰度可能导致了其偏好取食纤维素高的椰子老叶,而椰心叶甲则相反。同时,椰子织蛾肠道内显著较高的维生素B含量在其族群发展过程中起到了主要作用。两者细菌丰度以及代谢通路强度的差异可能影响了两者的食性。     

WHBE兔与日本大耳白兔腹泻型肠易激综合征模型的肠道菌群研究

目的比较分析WHBE兔和日本大耳白(Japanese white rabbit,JW)兔腹泻型肠易激综合征(irritable bowel syndrome,IBS)模型肠道菌群的差异性。方法 WHBE兔和JW兔各16只,按品系随机分为两组,即正常对照(NC)组和IBS模型组,每组8只。采用湿热应激复合番泻叶方法建立腹泻型IBS兔模型,观察实验兔的腹围指数、粪便含水量、结肠转运功能,处死后分别取结肠组织和结肠内容物进行病理组织学观察和肠道菌群多样性分析。结果与NC组比,IBS模型兔均出现腹围指数和粪便含水量增加,结肠转运时间缩短,但结肠组织未见病理性改变;同时IBS模型兔Shannon指数和Chao1指数均显著下降(P0.05)。根据OTU分类分析的结果,厚壁菌门和拟杆菌门为兔肠道菌群的绝对优势菌群。与NC组比较,WHBE兔IBS模型组厚壁菌门、疣微菌门、绿弯菌门、Akk菌属、链球菌属均明显下降(P0.05,P0.01),拟杆菌门和rc4-4菌属丰度显著上升(P0.05,P0.01);而JW兔IBS模型组优杆菌属和罕见小球菌属均显著上升(P0.05),乳酸杆菌属、粪杆菌属、韦荣球菌属和链球菌属均显著下降(P0.05)。与JW兔NC组比,WHBE兔NC组厚壁菌门、Odoribacter菌属、韦荣球菌属、链球菌属、颤螺旋菌属、Pseudoflavonifractor菌属较低(P0.05,P0.01),拟杆菌门、疣微菌门、优杆菌属、粪杆菌属、Akk菌属较高(P0.05,P0.01)。与JW兔IBS模型组比,WHBE兔IBS模型rc4-4菌属、粪杆菌属、梭菌属的丰度较高(P0.05,P0.01),而厚壁菌门、多尔氏菌属、粪球菌属和罕见小球菌属的丰度则较低(P0.05,P0.01)。结论 IBS模型兔存在肠道菌群失调,导致菌群多样性降低;WHBE兔和JW兔IBS模型肠道菌群变化均具有其自身的特点,且具有明显的差异性。     

利福平对红裸须摇蚊幼虫肠道微生物群落结构及功能的潜在影响北大核心

【目的】摇蚊是水生生态系统中重要的昆虫种类之一,其肠道微生物与个体生长发育、环境适应等过程密切相关,本研究旨在探究抗生素处理对摇蚊幼虫肠道微生物群落结构及功能的潜在影响。【方法】利用16S rRNA基因扩增子测序技术对利福平处理的红裸须摇蚊(Propsilocerus akamusi)幼虫肠道内容物中的菌群进行分析和比较,应用Tax4Fun法对其肠道菌群功能进行预测。【结果】利福平处理能够改变红裸须摇蚊幼虫肠道群落结构和多样性,宿主肠道菌群中拟杆菌门(Bacteroidota)(P<0.05)以及脱铁杆菌门(Deferribacterota)(P<0.001)的相对丰度显著上升,而变形菌门(Proteobacteria)与厚壁菌门(Firmicutes)相对丰度有所下降。在属水平上,利福平处理使耶尔森菌属(Yersinia)、假单胞菌属(Pseudomonas)、脱硫弧菌属(Desulfovibrio)的相对丰度有所降低,其中脱硫弧菌属(Desulfovibrio)显著降低。与此同时,共线性网络分析表明利福平处理后细菌群落稳定性大幅下降,菌种之间关联性显著减弱。通过京都基因与基因组百科全书(Kyoto encyclopedia of genes and genomes,KEGG)通路注释预测出红裸须摇蚊幼虫肠道菌群基因与基因信息处理、新陈代谢、人类疾病等功能相关,利福平处理可以使肠道菌群基因的抗药性功能显著上升,而内分泌和代谢疾病功能显著下降。【结论】研究结果揭示了抗生素利福平对红裸须摇蚊幼虫肠道细菌群落结构及功能的潜在影响,为进一步探索摇蚊肠道菌群发挥的必要作用奠定理论基础。     

冬眠对达乌尔黄鼠盲肠菌群的影响

冬眠哺乳动物的肠道微生物会发生季节性变化,同时在冬眠期间动物处于禁食状态,对肠道微生物的多样性和组成也产生影响。本研究通过16S rRNA基因高通量测序分析达乌尔黄鼠育肥阶段 (起始育肥期、快速育肥期、育肥完成期) 和冬眠阶段 (冬眠早期、冬眠晚期、出眠期) 共6个时期盲肠菌群的多样性、组成和功能,并通过冗余分析 (RDA) 探究其生理特征与菌群组成和功能之间的关系,揭示达乌尔黄鼠盲肠菌群的季节性变化。菌群组成的分析显示达乌尔黄鼠盲肠菌群主要由厚壁菌门 (Firmicutes)、拟杆菌门 (Bacteroidetes) 和疣微菌门 (Verrucomicrobia) 组成。与其他时期相比,冬眠早期厚壁菌门的相对丰度减少,拟杆菌门和疣微菌门的相对丰度增加。在Alpha多样性中,起始育肥期、快速育肥期和冬眠早期的Chao1和ACE指数显著低于出眠期,育肥完成期的Simpson指数显著低于快速育肥期 (P < 0.05) 。通过加权和非加权的UniFrac距离矩阵的主坐标分析发现盲肠菌群均显示出了明显的季节性聚类。PICRUSt分析中,丁酸代谢等代谢通路在育肥阶段富集,冬眠阶段集中在氮代谢等相关通路中。RDA分析显示达乌尔黄鼠不同时期的生理特征与其盲肠菌群的组成和功能显著相关。本研究表明,冬眠使达乌尔黄鼠盲肠菌群的多样性和相对丰度发生改变,盲肠菌群组成和功能的变化调节了达乌尔黄鼠的生理代谢,使达乌尔黄鼠适应季节性的环境变化。     

介绍一种新型的实验动物—高原鼠兔

鼠兔属动物的早期人工饲养开始于Dice对科罗拉多鼠兔(Ochotona priceps saratilis)的试养,室内繁殖未成功,直至1969年Puget从阿富汗喀布尔地区,捕获野生的阿富汗鼠兔(O. rufescens rufescens),并在人工饲养下繁殖成功。日本1974年引进作为基础对其进行实验动物化培育,供医学生物学研究用,目前已成为法、美和日本等国的实验动物。 高原鼠兔(O. curzoniac)的人工饲养始于60年代,由于鼠兔繁殖生物学因素的影响,     

基于16S rDNA与1H NMR技术探讨高脂血症兔肠道菌群和代谢物变化

目的 观察高脂血症模型兔的代谢物与肠道微生物变化并分析其相互关系。方法 雄性新西兰兔16只,随机分为正常组和模型组,每组8只。正常组喂普通饲料,模型组高胆固醇饮食。12周后比较2组兔血脂水平。利用16S rDNA测序技术检测兔粪便肠道菌群变化,采用1H NMR代谢组学分析结肠代谢物改变。结果 与正常组比较,模型组兔血清LDL-C、TG、TC水平显著升高（均P<0.01）;模型组兔肠道菌群结构发生改变,厚壁菌门、Lachnospiraceae＿NK4A136＿group、un＿f＿Lachnospiraceae、Subdoligranulum等菌群丰度上升,Lachnospiraceae＿NK4B4＿group、un＿o＿Gastranaerophilales等菌属丰度下降。2组差异代谢物通路分析主要涉及谷氨酰胺与谷氨酸代谢,丙氨酸、天冬氨酸和谷氨酸代谢,磷脂代谢。Lachnospiraceae＿NK4A136＿group、un＿f＿Lachnospiraceae、un＿o＿Gastranaerophilales等菌属与差异代谢物有较强相关性。结论 高脂血症的病理过程可能通过Lac...     

Environmental filtering increases with elevation for the assembly of gut microbiota in wild pikas

Despite their important roles in host nutrition, metabolism and adaptability, the knowledge on how the mammalian gut microbial community assemble is relatively scanty, especially regarding the ecological mechanisms that govern microbiota along environmental gradients. To address this, we surveyed the diversity, function and ecological processes of gut microbiota in the wild plateau pika, Ochotona curzoniae, along the elevational gradient from 3106 to 4331 m on ‘the Roof of the World’—Qinghai-Tibet Plateau. The results indicated that the alpha, beta and functional diversity of gut microbiota significantly increased with elevation, and elevation significantly explained the variations in the gut microbial communities, even after controlling for geographical distance, host sex and body weight. Some gene functions (e.g. nitrogen metabolism and protein kinases) associated with metabolism were enriched in the high-altitude pikas. Null model and phylogenetic analysis suggest that the relative contributions of environmental filtering responsible for local gut communities increased with elevation. In addition, deterministic processes dominated gut microbial communities in the high-altitude (more than 3694 m) pikas, while the percentages of stochastic and deterministic processes were very close in the low-altitude (3106 and 3580 m) pikas. The observed mechanisms that influence pika gut microbiota assembly and function seemed to be mainly mediated by the internal gut environment and by the external environmental pressure (i.e. lower temperature) in the harsh high-altitude environment. These findings enhance our understanding of gut microbiota assembly patterns and function in wild mammals from extreme harsh environments.     

SHOREBIRDS OF COASTAL BUENOS AIRES PROVINCE, ARGENTINA

The Pampas shorebird community is comprised of species from diverse taxonomic and faunal origin. Four major groups can be recognized: North American migrants residing in coastal Buenos Aires Province during their non-breeding season, Patagonian species wintering locally but breeding further south, Pampean species breeding locally, and Brazil–Paraguayan species present during their breeding season. Because of differences among these groups in the timing and migration patterns, community composition shows marked seasonal variation. Both nesting and non-breeding birds use a diversity of habitat types ranging from littoral sandy beaches to upland grasslands. Throughout the year, however, and in all habitat types, non-breeders predominate in species number and abundance. Intra- and inter-specific patterns of aggression suggest both that resources are limiting, and that non-breeding migrants may play an important role in determining breeding community composition.     

Comparative study of gut microbiota from captive and confiscated-rescued wild pangolins

Pangolins are among the most critically endangered animals due to widespread poaching and worldwide trafficking. Captive breeding is considered to be one way to protect them and increase the sizes of their populations. However, comparative studies of captive and wild pangolins in the context of gut microbiota are rare. Here, the gut microbiome of captive and confiscated-rescued wild pangolins is compared, and the effects of different periods of captivity and captivity with and without antibiotic treatment are considered. We show that different diets and periods of captivity, as well as the application of antibiotic therapy, can alter gut community composition and abundance in pangolins. Compared to wild pangolins, captive pangolins have an increased capacity for chitin and cellulose/hemicellulose degradation, fatty acid metabolism, and short-chain fatty acid synthesis, but a reduced ability to metabolize exogenous substances. In addition to increasing the ability of the gut microbiota to metabolize nutrients in captivity, captive breeding imposes some risks for survival by resulting in a greater abundance of antibiotic resistance genes and virulence factors in captive pangolins than in wild pangolins. Our study is important for the development of guidelines for pangolin conservation, including health assessment, disease prevention, and rehabilitation of wild pangolin populations.     

Effects of captivity,diet, and relocation on the gut bacterial communities of white‐footed mice

Microbes can have important impacts on their host's survival. Captive breeding programs for endangered species include periods of captivity that can ultimately have an impact on reintroduction success. No study to date has investigated the impacts of captive diet on the gut microbiota during the relocation process of generalist species. This study simulated a captive breeding program with white‐footed mice (Peromyscus leucopus) to describe the variability in gut microbial community structure and composition during captivity and relocation in their natural habitat, and compared it to wild individuals. Mice born in captivity were fed two different diets, a control with dry standardized pellets and a treatment with nonprocessed components that reflect a version of their wild diet that could be provided in captivity. The mice from the two groups were then relocated to their natural habitat. Relocated mice that had the treatment diet had more phylotypes in common with the wild‐host microbiota than mice under the control diet or mice kept in captivity. These results have broad implications for our understanding of microbial community dynamics and the effects of captivity on reintroduced animals, including the potential impact on the survival of endangered species. This study demonstrates that ex situ conservation actions should consider a more holistic perspective of an animal's biology including its microbes.     

Community structure of the gut microbiota in sympatric species of wild Drosophila

Many aspects of animal ecology and physiology are influenced by the microbial communities within them. The underlying forces contributing to the assembly and diversity of gut microbiotas include chance events, host‐based selection and interactions among microorganisms within these communities. We surveyed 215 wild individuals from four sympatric species of Drosophila that share a common diet of decaying mushrooms. Their microbiotas consistently contained abundant bacteria that were undetectable or at low abundance in their diet. Despite their deep phylogenetic divergence, all species had similar microbiotas, thus failing to support predictions of the phylosymbiosis hypothesis. Communities within flies were not random assemblages drawn from a common pool; instead, many bacterial operational taxonomic units (OTUs) were overrepresented or underrepresented relative to the neutral expectations, and OTUs exhibited checkerboard distributions among flies. These results suggest that selective factors play an important role in shaping the gut community structure of these flies.     

氮掺杂碳纳米颗粒对稻田根际土壤细菌群落的影响

氮掺杂碳纳米颗粒(N-CNPs)具有较高的农田氮肥增效潜力,但其对稻田根际土壤细菌群落结构和功能的影响尚不明确。本研究以连续3年施用低(1.2%,N-CNPs1)、中(6.7%,N-CNPs2)和高(9.3%,N-CNPs3)氮掺杂碳纳米颗粒的稻田根际土壤为研究对象,采用高通量测序技术和PICRUSt 功能预测方法研究其细菌群落组成和代谢功能变化。结果表明: 连续3年配施N-CNPs能提升稻田根际土壤细菌群落多样性,改变细菌群落功能;不同氮掺杂量水平间存在差异,其中以中氮掺杂量(N-CNPs2)碳纳米颗粒处理变化幅度最大。细菌群落分析结果指出,配施N-CNPs提升了根际土壤中变形菌门、酸杆菌门和疣微菌门的相对丰度,降低了浮霉菌门、绿弯菌门、硝化螺旋菌门和芽单胞菌门的相对丰度。PICRUSt 功能预测结果表明,在二级预测功能分类中,配施N-CNPs处理的氨基酸代谢、碳水化合物代谢和脂类代谢功能得到增强,而其他代谢功能则受到减弱。KEGG 直系同源基因簇丰度热图结果显示,N-CNPs2处理能提升根际土壤碳、氮代谢相关的细菌群落的相对丰度。     

The more the merrier? Multi-species grazing of small herbivores mediates plant community impacts

Small herbivores play keystone functional roles in grassland ecosystems. Recognising the combined effects where herbivores co-exist is important for guiding grassland restoration and biodiversity conservation. On the Tibetan Plateau, both plateau pikas and Himalayan marmots are regarded as pests by Tibetan people and local government, but little is known about their combined effects. We conducted a field study to determine the combined effects of pikas and marmots on plant biodiversity and vegetation structure. Plateau pikas alone consistently reduced the plant height and diversity and increased the vegetation cover of physically unpalatable plants. However, the co-existence of marmots with pikas decreased the vegetation cover of physically unpalatable plants, while increasing the cover of palatable plants and plant diversity, ultimately changing the impact of pikas alone and modulating aspects of the plant community. These results illustrate that increasing the abundance and richness of small herbivores in grassland ecosystems may promote plant diversity and benefit vegetation restoration rather than aggravate the degradation of grasslands.     

拮抗菌群对烟草野火病的防治效果及叶际微生物群落多样性的影响

【背景】烟草野火病(Tobacco Wild Fire)是烟草上的主要病害之一,利用拮抗菌防治烟草野火病是具有较好前景的防治手段。【目的】分析烟草叶际微生物群落结构组成和多样性,阐释拮抗菌群施用对烟草野火病的防治效果及对叶际微生物群落的影响。【方法】在烟草上施用3种拮抗菌群,采用16Sr RNA基因高通量测序及生物信息学手段,分析拮抗菌群对烟草叶际微生物群落结构组成和多样性的影响,研究拮抗菌群在叶片上的定殖。【结果】拮抗菌群对烟草野火病的防治效果达到50.44%-68.58%。与对照相比,3种拮抗菌群处理叶际微生物群落结构和组成都产生了明显的变化,群落多样性显著增高。拮抗菌群处理后,烟草叶际微生物泛菌(Pantoea)、寡养单胞菌(Stenotrophomonas)和假单胞菌(Pseudomonas)等菌属所占比例发生显著变化,其中芽孢杆菌属(Bacillus)和寡养单胞菌属相比对照增加分别达到3.9倍和7.02倍,其丰度与病情指数显著负相关。【结论】拮抗菌群对烟草野火病有较好的防治效果,施用拮抗菌群显著影响叶际微生物群落的组成和多样性,假单孢杆菌和寡养单胞菌等优势菌属能够在烟草叶际定殖,起到防治烟草野火病的作用。     

Environment and host species identity shape gut microbiota diversity in sympatric herbivorous mammals

The previous studies have reported that the mammalian gut microbiota is a physiological consequence; nonetheless, the factors influencing its composition and function remain unclear. In this study, to evaluate the contributions of the host and environment to the gut microbiota, we conducted a sequencing analysis of 16S rDNA and shotgun metagenomic DNA from plateau pikas and yaks, two sympatric herbivorous mammals, and further compared the sequences in summer and winter. The results revealed that both pikas and yaks harboured considerably more distinct communities between summer and winter. We detected the over-representation of Verrucomicrobia and Proteobacteria in pikas, and Archaea and Bacteroidetes in yaks. Firmicutes and Actinobacteria, associated with energy-efficient acquisition, significantly enriched in winter. The diversity of the microbial community was determined by the interactive effects between the host and season. Metagenomic analysis revealed that methane-metabolism-related pathway of yaks was significantly enriched in summer, while some pathogenic pathways were more abundant in pikas. Both pikas and yaks had a higher capacity for lipid degradation in winter. Pika and yak shared more OTUs when food shortage occurred in winter, and this caused a convergence in gut microbial composition and function. From winter to summer, the network module number increased from one to five in pikas, which was different in yaks. Our study demonstrates that the host is a dominant factor in shaping the microbial communities and that seasonality promotes divergence or convergence based on dietary quality across host species identity.     

盐度对滨海土壤细菌多样性和群落构建过程的影响

滨海盐土是重要的农业土地后备资源。微生物是土壤中物质循环的关键动力,然而盐度对土壤微生物群落特征影响的研究还很缺乏。本研究采集滨海地区的土壤样品,研究非盐、轻盐和高盐3组不同盐度对土壤细菌数量、多样性和群落构建的影响。结果表明: 与非盐和轻盐土壤相比,高盐土壤的脱氢酶活性和细菌数量显著降低,而细菌α多样性没有变化,细菌群落结构发生分异。利用零模型反演群落构建过程,发现盐度是细菌群落构建过程的主控因子,盐度主导的高确定性过程控制了滨海盐土细菌的群落结构。说明在现有的盐度范围内,高盐土壤中同样含有丰富的微生物种质资源,具有盐土改良的生物学基础,然而由于高确定性的群落构建机制,外源物种很难定殖于滨海盐土。因此,在利用微生物技术改良滨海盐土时,应尽可能筛选耐盐的土著菌种,提高定殖效率。