多元统计方法在节肢动物群落分析中的应用

近年来有关节肢动物群落的研究报道较多,而传统的、简单的多样性指数分析远远不能满足对高通量群落数据的挖掘。采用多元统计方法可以较好地分析群落数据。其中,在研究某一处理的长期效应时,主响应曲线是一种经典的多元分析方法;而非度量多维尺度分析具有能处理较大量的数据且常能以低维排序图反映结果的优点,是一种具有广泛应用前景的排序技术。本文以Bt棉与非Bt棉不同比例混作棉田的节肢动物群落为例,详尽地介绍了主响应曲线和非度量多维尺度在节肢动物群落分析中的应用。     

Pachytene analysis in oryza

Summary Pachytene analysis was undertaken in 4 japonica-indica rice hybrids. In all these hybrids, pairing was exceedingly abnormal lending evidence for structural hybridity. Earlier investigators who analysed metaphase-I and later stages of meiosis concluded that sterility is due to genic causes. The present investigation clearly points out the chromosomal causes of sterility and makes possible a reinterpretation of (1) non-recovery of recombinant phenotypes and (2) the occurrence of albina and other mutations in hybrid progenies.     

Drinking in adolescents--qualitative analysis

The aim of this paper was to explore alcohol consumption and the development of this habit in the adolescent population based on qualitative data from 59 anonymous essays written by high school students. We found that the most of adolescents had their first experiences with alcohol in the seventh or eighth grades. They reported that they usually drank alcohol to be happy, to relax, to be courageous in approaching the opposite sex, to fit into society, and to be popular. Factors affecting drinking are influence of peers, family and social attitude towards drinking, laws and enforcement of legislation. In further prevention programs, we must be able to demonstrate that "having a good time" does not mean drinking alcohol. Programs for the prevention of alcohol-related problems must begin by adolescence, including both sexes equally and can be achieved through a coordinated and intense public health effort.     

Pattern analysis in pseudanthia

Pseudanthia occur in more than 40 angiosperm families. With regard to the underlying inflorescence structure they can be classified into the following groups: (a) floral and (b) hyperfloral pseudanthia, each with (c) or without (d) pseudocorollas. Pseudanthia have developed along independent evolutionary lines and are not bound to a particular inflorescence structure. They are the result of (a) the specific morphological predisposition of the taxon concerned, (b) aggregation and diminution of the flowers, giving rise to the formation of an attraction unit (for animal pollination), (c) variation, and (d) selection. Ontogenetical abbreviation is regarded to play an essential role in the origin and elaboration of pseudanthia.Full-length version of a paper read at the 14th International Botanical Congress, Berlin 1987, Symposium 4–19.     

Immobilized enzymes in analysis

The sensitivity and specificity of enzyme reactions has led to the widespread use of enzymes as reagents in analysis. This article surveys the applications of immobilized enzymes in clinical analysis with particular emphasis on bioluminescent and chemiluminescent assays and test devices intended for use outside the main clinical laboratory.     

Complex-trait analysis in plants

Two recent studies in Arabidopsis have identified quantitative trait loci (QTLs) by population- association and family-based studies, respectively, providing further data on the genetic architecture of complex-trait variation in plants.     

Elemental analysis in biotechnology

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Gene analysis in rye

A number of recessive characters in rye were studied, seven of which in detail: anthocyanin-less (a); waxless (w); brittle (b); canary (c); yellow-green (yg) and two dwarfs (d ₁ end ₂). All are inherited monofactorially against the normal dominant character.Yellow-green showed a small but significant shortage of homozygous recessives, ascribed mainly to classification difficulties.For the study of the linkage relationships many, though not all combinations were made. Linkage betweend ₁ andyg, although seemingly significant, was considered unproven and improbable. Linkage betweend ₁ and a gene for prostrate growth was found probable. Linkage betweend ₁ andc was established, with a crossover percentage of 31. Here the situation was complicated by apparent absence of double recessives, best explained by cryptomeric masking (recessive epistasy) of the segregationD ₂-d ₂ bycc. If lethality of the double recessive class is assumed, the crossover percentage is 23.7.     

Comparison and analysis of objective functions in flux balance analysis

Flux balance analysis (FBA) is currently one of the most important and used techniques for estimation of metabolic reaction rates (fluxes). This mathematical approach utilizes an optimization criterion in order to select a distribution of fluxes from the feasible space delimited by the metabolic reactions and some restrictions imposed over them, assuming that cellular metabolism is in steady state. Therefore, the obtained flux distribution depends on the specific objective function used. Multiple studies have been aimed to compare distinct objective functions at given conditions, in order to determine which of those functions produces values of fluxes closer to real data when used as objective in the FBA; in other words, what is the best objective function for modeling cell metabolism at a determined environmental condition. However, these comparative studies have been designed in very dissimilar ways, and in general, several factors that can change the ideal objective function in a cellular condition have not been adequately considered. Additionally, most of them have used only one dataset for representing one condition of cell growth, and different measuring techniques have been used. For these reasons, a rigorous study on the effect of factors such as the quantity of used data, the number and type of fluxes utilized as input data, and the selected classification of growth conditions, are required in order to obtain useful conclusions for these comparative studies, allowing limiting clearly the application range on any of those results. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:985–991, 2014     

基元模式分析在生物网络和途径分析中的应用

基元模式分析是应用最广泛的代谢途径分析方法。基元模式分析的研究对象从代谢网络发展到信号传导网络;研究尺度从细胞到生物反应器,甚至生态系统;数学描述从稳态分解到动态解析;研究领域从微生物代谢到人类疾病。以下综述了基元模式分析的算法和软件开发现状,以及其在代谢途径与鲁棒性、代谢通量分解、稳态代谢通量分析、动态模型与生物过程模拟、网络结构与调控、菌株设计和信号传导网络等方面的应用。开发新的算法解决组合爆炸问题,探索基元模式与代谢调控的关系以及提高菌株设计算法效率是今后基元模式的重要发展方向。