水源污染引起鸭大肠杆菌病的诊治

对某种鸭场发生的鸭病，通过流行病学调查、临床症状分析、病理变化观察、病原分离鉴定以及饮水和病料的检测，诊断为大肠杆菌污染水源所致的鸭大肠杆菌病．将从饮水和病料中分离到的致病性大肠杆菌作药敏试验，用对该菌高度敏感的药物治疗病鸭，同时改进水源，病情缓解，疫情得到控制     

A dynamic view of peptides and proteins in membranes

Biological membranes are highly dynamic supramolecular arrangements of lipids and proteins, which fulfill key cellular functions. Relatively few high-resolution membrane protein structures are known to date, although during recent years the structural databases have expanded at an accelerated pace. In some instances the structures of reaction intermediates provide a stroboscopic view on the conformational changes involved in protein function. Other biophysical approaches add dynamic aspects and allow one to investigate the interactions with the lipid bilayers. Membrane-active peptides fulfill many important functions in nature as they act as antimicrobials, channels, transporters or hormones, and their studies have much increased our understanding of polypeptide-membrane interactions. Interestingly several proteins have been identified that interact with the membrane as loose arrays of domains. Such conformations easily escape classical high-resolution structural analysis and the lessons learned from peptides may therefore be instructive for our understanding of the functioning of such membrane proteins. Received 11 March 2008; received after revision 2 May 2008; accepted 5 May 2008