Proteomic analysis of latex from Jatropha curcas L. stems and comparison of two classic proteomic sample isolation methods: The phenol extraction and the TCA/acetone extraction

BackgroundJatropha curcas is a wide-spreading latex-rich biodiesel plant with high oil content in seeds that have always been under intense studies. However, studies are lacking on the latex component that is considered rich in proteins with potentially important physiological functions and secondary metabolites that are a promising source for new drugs. The proteomic analysis, which would be the first step to study these substances, was hampered by the presence of interfering components. Phenol extraction and Trichloroacetic acid (TCA)/acetone extraction, two major plant proteomic isolation methods, were used and compared in this study.ResultsWe identified 459 proteins from the J. curcas latex proteome using the combination of the two extraction techniques. Although more number of latex proteins were identified by the phenol extraction (401 proteins vs. 123 proteins by the TCA/acetone extraction), only 65 proteins were commonly isolated by both methods. Analysis of the biochemical properties revealed that relatively more number of lower isoelectric point (pI) proteins were isolated by the TCA/acetone method (pI mode: 4.79, 6.51 for phenol). Moreover, GO, COG, and KEGG analyses showed that certain classes/categories/pathways annotated more number of proteins than others, and most of them had proportionally comparable protein counts by both the methods, however, with exemplified exceptions.ConclusionsA large number of proteins were found and exclusively identified by either method, indicating that a better proteome coverage of plant samples in a similar context needs the combined use of multiple isolation methods. In addition, the core biological function of the latex may be uncovered by certain GO, COG, and KEGG classes/categories/pathways that annotate more proteins.     

资源型工业基地国际经验比较与东北振兴对策

结合《中共中央关于制定国民经济和社会发展第十一个五年规划的建议》提出的在东北地区建立重要装备工业基地的精神,分析世界各国主要资源型老工业基地的发展经验,指出借鉴国外先进经验、充分认识我国东北区域具体情况、制定因地制宜的振兴策略是东北老工业基地发展的必由之路。比较中国东北与德国莱茵-鲁尔、英国英格兰、美国东北、日本北九州等资源型老工业基地的异同,建议实施国家政策扶持、制定区域发展规划、做好国企改造、建立社会保障制度、设立振兴基金、基地分类指导、发展城市集群等措施振兴中国东北老工业基地。