污染胁迫下的分子生物标志物和分子诊断技术

在环境科学领域中,细胞和分子水平的生物标志物由于其特异性和实用性等优点,在近年来已经被广泛认可。传统的分子生物标志物,如超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malonaldehyde,MDA)、8-羟基脱氧鸟苷(8-hydroxydeoxyguanosine,8-OHdG)等,往往只能表征某类胁迫的程度,但却不能解释损伤和响应发生的分子机理,也不能精确地指示环境污染物的种类。新技术(高效液相色谱,气质联用,酶联免疫法等)的发展提升了传统分子生物标志物的检测灵敏度和特异性。为了加深对分子毒理学机理,筛选和确定新的分子生物标志物,一些新技术常着眼于提高筛选通量,提升可操作性和降低成本(如组学技术,单细胞凝胶电泳,报告生物体)。分子诊断的概念起初来源于临床诊断,转而被引入到环境科学研究中来,因为环境和人体一样是一个复杂的系统,环境污染可以看作一个复杂系统的疾病。为了更快更有效地筛选合适的生物标志物,需要广泛开展对模式生物的组学研究和致毒分子机制的研究。同时,也应注意研究过程中的标准化(如谨慎选择暴露浓度和时间,代表物种和其特定的生活史阶段)。     

Response of plasma fatty acid profiles to changes in dietary n‐3 fatty acids and its correlation with erythrocyte fatty acid profiles in dogs

An elevated level of long‐chain n‐3 fatty acids (FA) in tissue membranes has a positive influence on the progression and treatment of many diseases. Therefore, dietary supplementation of n‐3 FA is recommended in some diseases. Even though n‐3 FA are absorbed readily from the diet, their incorporation into tissues may be compromised in diseased animals. In a clinical setting, it is desirable to monitor the success of dietary intervention. Plasma FA as well as erythrocyte membrane (EM) FA can be used to monitor dietary FA intake. This study compares FA from EM and plasma with regard to their reaction time and reliability for monitoring dietary changes of tissue FA profiles in dogs. Thirty dogs were divided into three groups and fed for 12 weeks. The control group (CONT) was fed a commercial standard diet low in n‐3 FA. One group received the standard diet and 85 mg/kg body weight of a docosahexaenoic acid (DHA) concentrate (ADD). The third group was fed a commercial dog food containing fish oil (FO), which is rich in eicosapentaenoic acid (EPA). EM and plasma FA profiles were analysed by GC separately. Data on EM FA were published recently. n‐3 FA in plasma reached the new level after 2 weeks (8 weeks in EM). Dietary differences between DHA and EPA are obvious after 1 week already. The concomitant decrease in plasma n‐6 FA differed between ADD and FO. In general, the correlation of n‐6 FA between plasma and EM was low. We therefore conclude that analysis of plasma FA is sufficient for monitoring a diet‐induced increase in tissue n‐3 FA in dogs. However, EM FA should be analysed if the effect of dietary intervention on tissue n‐6 FA is important.     

c-Jun N-Terminal Kinase Phosphorylation Is a Biomarker of Plitidepsin Activity

Plitidepsin is an antitumor drug of marine origin currently in Phase III clinical trials in multiple myeloma. In cultured cells, plitidepsin induces cell cycle arrest or an acute apoptotic process in which sustained activation of c-Jun N-terminal kinase (JNK) plays a crucial role. With a view to optimizing clinical use of plitidepsin, we have therefore evaluated the possibility of using JNK activation as an in vivo biomarker of response. In this study, we show that administration of a single plitidepsin dose to mice xenografted with human cancer cells does indeed lead to increased phosphorylation of JNK in tumors at 4 to 12 h. By contrast, no changes were found in other in vitro plitidepsin targets such as the levels of phosphorylated-ERK, -p38MAPK or the protein p27^KIP1. Interestingly, plitidepsin also increased JNK phosphorylation in spleens from xenografted mice showing similar kinetics to those seen in tumors, thereby suggesting that normal tissues might be useful for predicting drug activity. Furthermore, plitidepsin administration to rats at plasma concentrations comparable to those achievable in patients also increased JNK phosphorylation in peripheral mononuclear blood cells. These findings suggest that changes in JNK activity provide a reliable biomarker for plitidepsin activity and this could be useful for designing clinical trials and maximizing the efficacy of plitidepsin.     

3个湖泊中黄颡鱼（Pelteobagrus fulvidraco）体内CYP1A1和GST的比较及其功效分析

环境中污染物生物标志物的选取和研究是环境监测的重要内容之一,作为污染物肝脏解毒作用的关键酶,多功能氧化酶（CYP1A1）和谷胱甘肽硫转移酶（GST）常被用来作为多种污染物监测的生物标志物。比较了3个湖泊（巢湖、洪泽湖和鄱阳湖）黄颡鱼（Pelteobagrus fulvidraco）体内的CYP1A1和GST的活性,并对其进行功效分析。结果显示,3个湖泊中黄颡鱼体内CYP1A1和GST之间呈现反相关关系;洪泽湖黄颡鱼体内CYP1A1值明显小于其他两个湖,而洪泽湖黄颡鱼体内GST值明显大于巢湖,与鄱阳湖相比差     

湿地匍灯藓（Plagiomnium acutum）对Pb胁迫的生物标志物响应

采用浸没培养实验研究了不同浓度Pb胁迫下湿地匍灯藓（Plagiomniumacutum）的总叶绿素、丙二醛、可溶性糖、游离脯氨酸含量以及抗氧化酶活性等生理生化生物标志物的变化,以探讨Pb胁迫下湿地匍灯藓的受损和耐受机理。结果表明,湿地匍灯藓外表伤害症状与Pb胁迫浓度存在明显的剂量-效应关系;低浓度（20mg·L-1）Pb胁迫可以显著地促进湿地匍灯藓的总叶绿素含量增加,而中、高浓度（50mg·L-1）Pb胁迫则导致总叶绿素含量显著降低。湿地匍灯藓对Pb具有较强的生物富集能力,且藓体Pb的累积量与环境Pb浓度呈显著正相关。湿地匍灯藓体内MDA和游离脯氨酸含量随Pb胁迫浓度的增加表现为显著升高。可溶性糖含量仅在高浓度Pb胁迫下显著升高。可溶性蛋白含量、过氧化物酶（POD）和过氧化氢酶（CAT）活性均随Pb胁迫浓度的增加而显著下降,其中CAT活性的降幅最大,SOD活性随Pb胁迫浓度的增加逐渐显著增加。在高浓度Pb胁迫下,由于细胞膜脂过氧化和蛋白质变性失活所导致的膜保护体系损伤可能是湿地匍灯藓Pb中毒的主要原因,而渗透调节可能是其缓解Pb毒害的一种主要方式,SOD则在清除Pb胁迫产生的活性氧自由基过程中起重要作用。总叶绿素、丙二醛、游离脯氨酸、可溶性蛋白、CAT和SOD可以作为湿地匍灯藓受Pb胁迫的敏感生物标志物。     

循环microRNA在冠心病及其中医证候诊断中的作用

microRNA是一类长度约为22个核苷酸的内源性非编码RNA,并能以特定的方式与靶基因结合,从而抑制靶基因的翻译或使其降解。microRNA只有在受到致病因素（如环境因素）的影响以及病理状态下,其表达量才会发生改变,因此microRNA具有成为各种疾病的诊断生物标志物的可能。目前有大量研究表明microRNA参与冠心病发生发展,但其作用机制尚未完全阐明,本文从microRNA的特性、microRNA与冠心病、microRNA与中医证候等方面对近年来国内外的研究做一综述。     

蛋白质组学研究进展及其在中兽医学中的应用探讨

随着生命科学研究进入后基因组时代,蛋白质组学作为重要的实验技术,已经成为筛选重大疾病的特异生物标志物和研究发病机理的新途径。文章总结了蛋白质组学研究的主要内容和方法,简述了蛋白质组学在生命科学的应用概况,并探讨了其在中兽医学研究中的应用前景。