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.     

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,     

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.     

肠道菌群：膳食与健康研究的新视角

近年来,随着“人类微生物组计划”、“肠道元基因组计划”等研究项目的开展,人类对肠道菌群的关注达到了空前的高度。随着对其结构和功能的不断挖掘,人们发现肠道菌群与宿主健康密切相关,甚至被认为是“被忽略的人体器官”。最新的研究报道表明,包括帕金森病、乳腺癌、艾滋病、肝硬化、肾病、关节炎、糖尿病等在内的疾病都与肠道微生物结构异常相关;同时最近有很多研究从肠道菌群的角度关注了食品甜味剂、食品乳化剂、节食等因素对机体的影响;另外,肠道菌群也已成为我们阐释益生菌、益生元、微量元素、多酚化合物等膳食因子调控健康研究的着眼点。可以预见,随着肠道微生物研究方法和手段的不断发展,肠道菌群有可能成为多种疾病预测诊断的标志物;同时,许多人类疾病的发病机制及干预机制、食物保健功能等将有可能通过肠道微生态理论而得到更好地诠释和补充。     

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     

胃肠激素对胃运动的影响

本研究将胃肠运动的体液性调节机制即胃肠激素对胃运动的影响进行了实验研究,结果显示：血清素和胃动素对麻醉状态下的家兔的胃运动有明显的促进作用,且作用时间持久。说明血清素和胃动素对胃肠运动起着重要的调节作用。     

Regulatory peptide receptors: visualization by autoradiography

Summary The receptors for regulatory peptides have been extensively characterized using radioligand binding techniques. By combining these binding techniques with autoradiography it is possible to visualize at the light and electron microscopic levels the anatomical and cellular localization of these receptors. In this review we discuss the procedures used to label peptide receptors for autoradiography and the peculiarities of peptides as ligands. The utilization of autoradiography in mapping peptide receptors in brain and peripheral tissues, some of the new insights revealed by these studies particularly the problem of mismatch between endogenous peptides and receptors, the existence of multiple receptors for a given peptide family and the use of peptide receptor autoradiography in human tissues are also reviewed.     

葡萄籽原花青素对营养肥胖模型大鼠肠道菌群的影响

以高脂膳食喂养大鼠,复制营养肥胖模型,然后灌胃原花青素,采用变性梯度凝胶电泳,实时荧光定量等不依赖微生物培养的手段和多元统计分析方法,研究葡萄籽原花青素对营养肥胖模型大鼠肠道菌群生态的影响。结果表明,低剂量(100mg/(kg·体重·d))原花青素可以显著抑制大鼠肥胖,处理后大鼠肠道菌群结构与模型组分离;葡萄籽原花青素显著降低了肥胖大鼠肠道菌群中厚壁菌门的含量,提高了拟杆菌门的含量,显著降低了厚壁菌门与拟杆菌门比值;实时荧光定量检测显示,原花青素可以促进拟杆菌增殖,抑制柔嫩梭菌增殖,初步揭示出葡萄籽原花青素可能具有调节肠道菌群的功能;原花青素作用的关键微生物种属为Blautia, Bacteroides, Lactobacillus, Anaerostipes, Clostridium, Anaerofilum。     

中华蜜蜂肠道细菌群落的PCR-DGGE分析

肠道微生物与中华蜜蜂的生长发育密切相关,在为宿主提供营养、抵抗病原菌侵袭等方面起重要作用.为了探究中华蜜蜂在封盖一日龄蛹、破巢幼蜂和采集蜂三个重要发育阶段肠道细菌群落的结构组成及差异变化,我们对细菌16S r DNA的V6-V8可变区进行PCR-DGGE和克隆测序,并计算封盖一日龄蛹、破巣蜂和采集蜂阶段中华蜜蜂肠道菌群的多样性指数和相似性系数,结果表明:采集蜂肠道内细菌多样性指数最大,而封盖一日龄蛹和破巣幼蜂之间的肠道菌群相似性较高;测序结果初步得到了Gilliamella、Snodgrassella、Carnobacterium、Neisseriaceae、Frischella、Janthinobacterium、Pseudomonas、Lactobacillus、Lactococcus和Leuconostoc十种菌属,其中封盖一日龄蛹和破巢幼蜂的优势菌属为Snodgrassella和Pseudomonas;采集蜂的优势菌属为Gilliamella和Snodgrassella.本研究旨在为提高中华蜜蜂的环境适应性和病虫害的防治提供依据.