Natural diet of fish and crabs associated with the phytal community of Sargassum cymosum C. Agardh, 1820 (Phaeophyta,Fucales) at Ponta das Garoupas,Bombinhas, Santa Catarina State,Brazil

The diet of fish and crabs associated with Sargassum cymosum beds was analysed at Ponta das Garoupas, Santa Catarina State, southern Brazil. They are reported to feed on phytal organisms. The relative importance of food items was established for these consumers, and the frequency of occurrence and volumetric methods were used for quantitative analysis. The analysis of 272 guts from 11 fish and two decapod species revealed that eight fish and one crab species had phytal organisms as important items in their diet. Amphipods and molluscs were the main phytal animals in the diet of these fish and the crab; notably Caprella scaura, Hyale media, Atylus minikoi, Tricolia affinis and Bittium varium. Commercially important fish, such as the grouper Epinephelus guaza, feed on these fish and crabs, showing that Sargassum beds constitute an important link between benthic autotrophic producers and several levels of consumers on rocky shore ecosystems at Ponta das Garoupas.     

人体肠道微生物对十溴联苯醚的代谢研究

十溴联苯醚(BDE209)是一种具有持久性有机污染物特征的溴系阻燃剂, 可在生物体代谢生成更高毒性的化合物. 本文利用从人体粪便中提取的微生物以及通过人体肠道微生态系统模拟装置培养的人体肠道微生物, 在体外条件下研究BDE209 在人体肠道微生物作用下的代谢. 结果表明在为期10 d 的反应时间里, BDE209 含量保持稳定, 在气相色谱-质谱联用仪(GCNCI-MS)的色谱图中也没有检测到可能的脱溴代谢产物, 说明BDE209 没有发生显著的脱溴代谢作用.     

基于16S rRNA基因扩增子测序技术研究云南野生小型哺乳动物肠道菌群多样性

以生活在同一生境,但具有不同进化关系和不同食性的野生哺乳类动物(鼠科、猬科和鼩鼱科)为研究对象,通过16S rRNA基因扩增子测序,分析和比较其肠道菌群.共识别出5378个操作分类单位(OTUs),主要隶属 Firmicutes(40.55％),Proteobacteria(34.60％)和 Bacteroidetes...     

Seasonal variation of gut Cyanophyta contents and liver GST expression of mud carp （Cirrhina molitorella） and Nile tilapia （Oreochromis niloticus） in the tropical Xiangang Reservoir （Huizhou, China）

Liver glutathione S-transferase(GST) plays a major role in the detoxification of microcystins(MCs) via conjugation to glutathione(GSH).We evaluated the relationship between seasonal variation in fish gut contents and the expression of GST isoforms in mud carp(Cirrhina molitorella) and Nile tilapia(Oreochromis niloticus).We quantified the abundance and diversity of plankton in the water column and foregut of mud carp and Nile tilapia in the tropical Xiangang Reservoir between October 2007 and July 2008.The mRNA expression of 7 liver GST isoforms was determined by real-time RT-PCR.The gut contents of both species were dependent on the amount and type of phytoplankton and zooplankton in the water.The expression of liver GST genes in Nile tilapia and mud carp was positively and negatively correlated,respectively,with the abundance of toxic cyanobacteria in the fore-gut.The expression of liver GST mRNA was correlated to the abundance of toxic cyanobacteria in the gut contents of both species,suggesting that mRNA expression of GST isoforms could be used as a biomarker in Nile tilapia and mud carp to monitor cyanobacteria blooms in reservoirs.     

肠道菌群的形成及影响因素研究进展

肠道菌群对人体健康具有重要作用,而年龄、饮食、抗菌药物使用和心理压力等多种因素可以影响其形成和组成。本文就相关影响因素研究进展进行综述。     

The potential role of endogenous bacteriophages in controlling invading pathogens

Bacteriophages (phages) are omnipresent in our environment, and recent studies highlight their potential impact on the microbial world. Phages can also be present in mammalian organisms, including man (intestines, oral cavity, urine, sputum and serum). Data are available which suggest that those endogenous phages could play an important role in eliminating bacteria and regulating the body ecosystem. Furthermore, our most recent findings suggest that phages can exert immunosuppressive action in the gut, helping control local inflammatory and autoimmune reactions, and demonstrate anticancer activity. We hypothesize that phages could act in concert with the immune system in immunosurveillance against bacteria, viruses and cancer.article dedicated to Professor Ludwik Hirszfeld to commemorate the 50^th anniversary of his deathReceived 8 September 2004; received after revision 18 October 2004; accepted 21 October 2004     

Effect of dexamethasone on Fc γ receptor expression in foetal and neonatal rat gut

Summary When injected into 12-day-old suckling rats, dexamethasone caused a precocious disappearance of Fc receptors from enterocytes of the proximal small intestine. However, dexamethasone appeared to be necessary for the maintenance or production of such receptors in foetal rat gut cultured in vitro.Supported by an award from the Science and Engineering Research Council.     

酒精性肝损伤与小肠通透性改变的关系及中药的干预作用

近年来．肠道内毒素及其激活肝库普弗细胞产生炎症细胞因子机制是酒精性肝损伤机理研究的热点之一。研究表明酒精不仅作为一种肝脏毒剂,可削弱正常肝细胞的代谢及肝细胞的稳定性,损伤线粒体功能;同时酒精可致小肠通透性增加,使肠源性内毒素渗漏形成二次攻击,加重肝损伤。中药治疗酒精性肝病有悠久历史,其中健脾、调理脾胃运化功能,“升清降浊”是重要治则。这提示中药可能可以通过纠正酒精引起的小肠通透性改变以防治酒精性肝损伤,     

肠道菌群利用去淀粉麦麸体外发酵产短链脂肪酸

肠道菌群中不同菌对同一种不消化性碳水化合物的利用程度不同.本实验利用去淀粉麦麸(destarched wheat bran,DWB)作为碳源,用人体粪便作为肠道细菌来源,对不同肠道菌群进行体外发酵培养,在不同时间取其发酵液,测定发酵液内SCFA的种类和数量的变化.结果显示,肠道中各种细菌(包括非益生菌)均能利用DWB产...     

Cholinesterases are down-expressed in human colorectal carcinoma

The aberrations of cholinesterase (ChE) genes and the variation of ChE activity in cancerous tissues prompted us to investigate the expression of ChEs in colorectal carcinoma. The study of 55 paired specimens of healthy (HG) and cancerous gut (CG) showed that acetylcholinesterase (AChE) activity fell by 32% and butyrylcholinesterase (BuChE) activity by 58% in CG. Abundant AChE-H, fewer AChE-T, and even fewer AChE-R and BuChE mRNAs were observed in HG, and their content was greatly diminished in CG. The high level of the AChE-H mRNA explains the abundance of AChE-H subunits in HG, which as glycosylphosphatidylinositol (GPI)-anchored amphiphilic AChE dimers (G₂^A) and monomers (G₁^A) account for 69% of AChE activity. The identification of AChE-T and BuChE mRNAs justifies the occurrence in gut of A₁₂, G₄^H and PRiMA-containing G₄^A AChE forms, besides G₄^H, G₄^A and G₁^H BuChE. The down-regulation of ChEs might contribute to gut carcinogenesis by increasing acetylcholine availability and overstimulating muscarinic receptors. Received 19 May 2006; received after revision 5 June 2006; accepted 5 July 2006