Uninterrupted protein synthesis is essential for survival in the early stages of carbontetrachloride-induced hepatocellular necrosis in the mouse

Summary The fatal syndrome produced by cycloheximide given 6 h after a hepatonecrogenic dose of CCl₄ is due neither to direct toxic synergism between CCl₄ and cycloheximide nor to transient sinusoidal thrombosis. It is suggested that survival in the presence of unknown factors released from dying liver cells requires uninterrupted protein synthesis. The life-saving effect of sterilization of the intestine by antibiotics indicates that the gut flora or its products play a vital role in pathogenesis.Acknowledgments. I wish to thank Mr C. R. West for carrying out the statistical analysis, Mrs Brenda Brooks for histological processing, and Berk Pharmaceuticals Ltd for information on Ancrod defibrination in mice.     

The enteric neural receptor for 5-hydroxytryptamine

Summary An enteric neural receptor for serotonin (5-HT) has been characterized. This receptor was assayed, using³H-5-HT as a radiologand, by rapid filtration of isolated enteric membranes and by radioautography. In addition, intracellular recordings were made from ganglion cells of the myenteric plexus. High affinity, saturable, reversible, and specific binding of³H-5-HT was demonstrated both to membranes of the dissected longitudinal muscle with adherent myenteric plexus and the mucosa-submucosa. Radioautographs showed these³H-5-HT binding sites to be in myenteric ganglia and in a broad unresolved band at the mucosal-submucosal interface. Antagonists active at receptors for other neurotransmitters than 5-HT, at either of the two known types of CNS 5-HT receptor, and at 5-HT uptake sites on serotonergic neurons failed to inhibit binding of³H-5-HT. The structural requirements of analogues for binding to the enteric 5-HT receptor matched the known pharmacology of M or neural 5-HT receptors. A novel 5-HT antagonist was found. This compound, N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide (5-HTP-DP), antagonized the action of 5-HT on type II/AH cells of the myenteric plexus but did not affect the release or actions of acetylcholine (nicotinic or muscarinic) or substance P. 5-HTP-DP was also an equally potent displacer of³H-5-HT from its binding sites on enteric membranes. It is concluded that the sites responsible for specific binding of³H-5-HT are enteric M or neural 5-HT receptors. These receptors differ from those now known to be present in the CNS.     

不同摄入量小米对小鼠肠道菌群和短链脂肪酸的影响

摄入一定量杂粮可降低一些慢性代谢疾病的发病率,但目前杂粮摄入量没有统一的标准,尚不清楚杂粮摄入过多是否会对健康产生不良影响。以小米添加量为20%、40%、60%、80%的饲料喂养3周龄C57BL/6J小鼠,持续12周,采用自动血生化分析仪、16S rRNA高通量基因测序、气相色谱-质谱联用仪分析了不同摄入量小米对小鼠血脂水平、肠道菌群和粪便短链脂肪酸的影响。结果发现,80%摄入量的小米显著增加了小鼠血清的总胆固醇、高密度脂蛋白胆固醇和低密度脂蛋白胆固醇的水平,同时增加了肠道丙酸、丁酸、异丁酸和戊酸的含量。肠道菌群分析结果表明,所有小米干预组的拟杆菌门(Bacteroidota)、Muribaculaceae的丰度上升,厚壁菌门(Firmicutes)、放线菌门(Actinobacteriota)、乳杆菌科(Lactobacillaceae)、双歧杆菌属 (Bifidobacterium)的丰度下降。摄入不同添加量小米的小鼠肠道菌群组成具有较大差异,其中20%小米摄入量组的小鼠菌群中显著富集了另枝菌属(Alistipes)、副拟杆菌属(Parabacteroides)、肠杆菌属(Enterorhabdus),而80%摄入量小米显著降低了小鼠菌群中的粪杆菌属(Faecalibaculum)、布劳特氏菌属(Blautia)和罗氏菌属(Roseburia)的丰度。研究结果表明,20%摄入量的小米就能有效调节小鼠肠道菌群,而过高摄入量(80%)的小米使小鼠血脂水平升高,降低了肠道菌群的多样性和均匀度以及有益菌的丰度,所以要理性看待杂粮的营养价值,避免过量摄入。     

中华蜜蜂幼虫肠道响应球囊菌胁迫的可变剪切基因分析

基于前期已获得的中华蜜蜂(简称中蜂)幼虫肠道转录组数据,利用TopHat2软件在正常(AcCK)及球囊菌胁迫的中蜂幼虫肠道样品(AcT1、AcT2、AcT3)中共鉴定出发生于9124个基因的57327个可变剪切事件,其中以基因间(17.68%)、可变3′端剪切(15.32%)、外显子跨越(14.12%)和可变5′端剪切(12.81%)类型为主.Venn分析结果显示4个肠道样品的共有可变剪切基因数为8111个,特有可变剪切基因数分别为272、189和385个.GO分类结果显示共有可变剪切基因涉及47个条目,AcT1、AcT2、AcT3的特有可变剪切基因分别富集于24、20和34个条目.KEGG代谢通路富集分析结果显示,共有可变剪切基因富集在327个代谢通路,基因富集数最多的是RNA转运、内质网蛋白加工及核糖体;AcT1、AcT2、AcT3的特有可变剪切基因分别富集在22、46和83个代谢通路.结果揭示了可变剪切基因在宿主的胁迫响应过程中的重要作用.     

Role of serotonin in the hepato-gastroIntestinal tract: an old molecule for new perspectives

Beside its role as a neurotransmitter in the central nervous system, serotonin appears to be a central physiologic mediator of many gastrointestinal (GI) functions and a mediator of the brain-gut connection. By acting directly and via modulation of the enteric nervous system, serotonin has numerous effects on the GI tract. The main gut disturbances in which serotonin is involved are acute chemotherapy-induced nausea and vomiting, carcinoid syndrome and irritable bowel syndrome. Serotonin also has mitogenic properties. Platelet-derived serotonin is involved in liver regeneration after partial hepatectomy. In diseased liver, serotonin may play a crucial role in the progression of hepatic fibrosis and the pathogenesis of steatohepatitis. Better understanding of the role of the serotonin receptor subtypes and serotonin mechanisms of action in the liver and gut may open new therapeutic strategies in hepato-gastrointestinal diseases. Received 15 August 2007; received after revision 1 November 2007; accepted 5 November 2007     

Pathogenic enterococci: new developments in the 21st century

Enterococci, traditionally viewed as Gram-positive commensal bacteria inhabiting the alimentary canals of humans and animals, are now acknowledged to be organisms capable of causing life-threatening infections in humans, especially in the nosocomial environment. The existence of enterococci in such a dual role is facilitated, at least in part, by its intrinsic and acquired resistance to virtually all antibiotics currently in use. Beginning with the initial identification of a streptococci of fecal origin in the late 19th century, enterococci have been studied for over a century now. A number of comprehensive reviews during this time have addressed various aspects of enterococci, including classification, biology, virulence, antibiotic resistance and so on. This review specifically addresses the important advances in the field of enterococcal research that have occurred since the beginning of the 21st century. Most notable among these developments have been the insights into enterococcal genomes and pathogenicity.Received 10 April 2003; received after revision 31 May 2003; accepted 3 June 2003     

导盲犬和淘汰犬肠道菌群的差异性研究

目的 探究导盲犬和淘汰犬之间肠道菌群的差异,分析两者特征性差异菌群。方法 收集16只导盲犬和10只淘汰犬的新鲜粪便样本,按照犬品种和性别分为拉布拉多雄性导盲犬(GD-ML)和淘汰犬(ED-ML)、拉布拉多雌性导盲犬(GD-FL)和淘汰犬(ED-FL)、金毛雄性导盲犬(GD-MG)和淘汰犬(ED-MG),另外从中随机抽取9只导盲犬和4只淘汰犬分为导盲犬组(GD)和淘汰犬组(ED),共分为4组配对。提取粪便样本总DNA,应用PCR-DGGE技术获得肠道菌群图谱,应用相关软件和统计学方法对每组配对进行差异性分析。结果 聚类分析结果显示,GD和ED,GD-ML和ED-ML,GD-FL、ED-FL和GD-MG均各归为一类,表明导盲犬和淘汰犬之间肠道菌群存在差异。肠道菌群多样性、丰富度和均匀度分析结果显示,每两个配对组之间多样性指数、丰富度指数和均匀度指数存在差异,但差异均无统计学意义。差异性条带测序分析结果显示：与ED相比,GD Megamonas funiformis YIT 11815菌株增多;与ED-ML相比,GD-ML Succinatimonas hippei YIT 12066、Lactobacillus vaginalis DSM 5837、Lactobacillus acidophilus NCFM、Faecalibacterium prausnitzii A2-165菌株增多,Collinsella aerofaciens ATCC 25986和Prevotella copri DSM 18205菌株减少;与ED-FL相比,GD-FL Ruminococcus gnavus AGR2154、Fusobacterium russii ATCC 25533菌株减少;与ED-MG相比,GD-MG Tropheryma whipplei str. Twist菌株增多。结论 本研究发现导盲犬和淘汰犬肠道菌群存在差异,未来对差异菌群的进一步研究可能有助于辅助导盲犬的早期筛选。     

禽类肠道主要APUD细胞分布及其生理功能的研究进展

禽类动物肠道中存在许多能够分泌肽类激素的内分泌细胞(Amine Precursor Uptake and Decarboxylation Cells,APUD细胞),主要包括S细胞、G细胞、D细胞、PP细胞、I细胞、L细胞、N细胞、M细胞、K细胞,它们分别释放肠促胰液素、胃泌素和脑啡肽、生长抑素和血管活性肠肽、禽胰多肽、缩胆囊素、肠高血糖素、神经降压素、胃动素、葡萄糖依赖性促胰岛素多肽等相关激素,在禽类动物肠道的营养、消化吸收和免疫功能等方面发挥着重要的作用.对禽类肠道主要APUD细胞的种类、分布及生理功能的研究概况进行综述,为深入研究禽类肠道的生理功能提供参考.     

基于高通量测序的不同养殖系统下凡纳滨对虾肠道和水体中微生物的多样性

【目的】研究不同养殖系统对凡纳滨对虾肠道及水体微生物多样性的影响。【方法】以循环养殖系统和非养殖系统下凡纳滨对虾养殖水体及其肠道为研究对象,在养殖30d后采集样品,采用Illumina MiSeq高通量测序样品细菌16SrRNA基因V3+V4区,通过RDP11.3、Greengenes13.8、NCBI 16S Microbial和Customized batabase等数据库进行分析,阐述循环养殖系统的意义和微生物在其中的作用。【结果】养殖期间,不同养殖系统凡纳滨对虾均正常存活。将原始序列优化后对Clean序列进行分析,非循环系统下水体优质序列百分比约81%,肠道中约89%;循环系统下水体优质序列百分比为92%,肠道中为94%。两种养殖系统下水体和肠道细菌在纲水平占绝对优势的是变形菌纲,但各菌群丰度不同;不同的Alpha指数显示出物种间的差异性;通过系统发育树可以看出,不同养殖系统改变了凡纳滨对虾生境中的物种及发育关系,间接阐述微生物在养殖生境中的作用和意义。【结论】通过高通量测序揭示不同养殖系统中微生物菌群的差异以及多样性,对于凡纳滨对虾实际养殖具有指导作用,对阐述养殖过程中微生物和相关疾病的关系具有重要意义。     

灭活型副干酪乳杆菌L9常温酸奶调节肠道菌群缓解便秘作用研究

为评价灭活型副干酪乳杆菌L9常温酸奶润肠通便和调节肠道菌群的作用,招募便秘受试者61人,随机分为两组,分别饮用普通常温酸奶和含L9的常温酸奶28d,饮用结束后分析受试者便秘相关症状、粪便短链脂肪酸含量和肠道菌群的变化情况。结果显示:与常温酸奶组相比,灭活型副干酪乳杆菌L9常温酸奶组受试者排便次数显著增加(P<0.05),排便状况和粪便性状评分极显著降低(P<0.01);粪便中丁酸含量极显著增加(P<0.01),丙酸和总酸含量显著增加(P<0.05);并显著增加产短链脂肪酸的菌属,如Blautia、Ruminococcus＿2和＿hallii＿group。研究结果表明,与普通常温酸奶相比,灭活副干酪乳杆菌L9常温酸奶具有更好的调节肠道菌群缓解便秘的作用。本研究旨在为开发含有灭活副干酪乳杆菌L9的相关功能食品提供理论依据。