The minor transitions in hierarchical evolution and the question of a directional bias

The history of life shows a clear trend in hierarchical organization, revealed by the successive emergence of organisms with ever greater numbers of levels of nestedness and greater development, or ‘individuation’, of the highest level. Various arguments have been offered which suggest that the trend is the result of a directional bias, or tendency, meaning that hierarchical increases are more probable than decreases among lineages, perhaps because hierarchical increases are favoured, on average, by natural selection. Further, what little evidence exists seems to point to a bias: some major increases are known – including the origin of the eukaryotic cell from prokaryotic cells and of animals, fungi and land plants from solitary eukaryotic cells – but no major decreases (except in parasitic and commensal organisms), at least at the cellular and multicellular levels. The fact of a trend, combined with the arguments and evidence, might make a bias seem beyond doubt, but here I argue that its existence is an open empirical question. Further, I show how testing is possible.     

基于层次分析法的67种爵床科植物观赏价值综合评价

基于中国科学院西双版纳热带植物园收集保存的爵床科植物资源，运用层次分析法构建评价体系，对67种具有园林应用潜力的爵床科植物进行观赏价值综合评价。结果表明，在一级指标中，花观赏性所占权重最大，表示花观赏性在爵床科植物观赏价值综合评价中是最重要的方面；在二级指标中，花(序)量、花(序)色鲜艳度和盛花期时长对爵床科植物观赏价值的影响权重均超过10%，对评价结果有较大影响，而花(序)大小、花后观赏性和叶片盖度对爵床科植物观赏价值的影响权重均低于5%，对评价结果影响较小。依据指标权重和评分标准，对67种爵床科植物的观赏价值进行综合评分并划分等级，赤苞花(Megaskepasma erythrochlamys)、宽叶十万错(Asystasia gangetica)、鸟尾花(Crossandra infundibuliformis)、翠芦莉(Ruellia simplex)、翼叶山牵牛(Thunbergia alata)、金苞花(Pachystachys lutea)、黄花老鸦嘴(Thunbergia mysorensis)、白苞爵床(Justicia betonica)、叉花草(Strobilanthes hamiltoniana)、绯红珊瑚花(Pachystachys coccinea)、白金羽花(Schaueria calytricha)、山牵牛(Thunbergia grandiflora)等12种植物的观赏价值较高，综合评价等级为Ⅰ级，具有较好的园林应用前景。     

酵母菌快速鉴定新方法:用DHPA法及ID 32C试条鉴定酵母菌

目的：建立酵母菌快速鉴定新方法。方法：依据双歧鉴定法和层次分析原理建立DHPA法，用DHPA法及ID32C试条鉴定酵母菌。结果：DHPA法和32C法对酵母菌63个KIU鉴定的正确性均为100％。DHPA法与32C法对酵母菌3759个试验编码分析的总符合率为81．5％。结论：DHPA法解决了32C法存在的缺码或不能鉴定问题，是酵母菌准确、快速、简便、经济和实用的鉴定方法。     

Effect of Mother's Dominance Rank on Offspring Temperament in Infant Rhesus Monkeys (Macaca mulatta)

In humans, temperament plays an important role in socialization and personality. Some temperaments, such as behavioral inhibition are associated with an increased risk for psychopathology. Nonhuman primates can serve as a model for neurobiological and developmental contributions to emotional development and several recent studies have begun to investigate temperament in nonhuman primates. In rhesus monkeys, dominance rank is inherited from the mother and is associated with social and emotional tendencies that resemble differences in temperament. The current study assessed differences in temperament in infant rhesus monkeys as a function of maternal dominance rank. Temperament was assessed in 26 infants (13 males) from birth until 6 months of age with a battery that included Brazelton test, human intruder test, human intruder‐startle, cortisol stress reactivity, and home cage observations of interactions with peers and the mother. Throughout testing, infants lived with their mothers and a small group of other monkeys in indoor/outdoor runs. Dominance rank of the mothers within each run was rated as either low/middle (N = 18, 9 male) or high/alpha (N = 8, 4 female). Infants of high‐ranking mothers displayed more intruder‐directed aggression and reduced startle potentiation in the human intruder tests. Dominant offspring also had reduced levels cortisol and startle across development and spent more time away from mothers in the interaction tests. These results suggest that dominance of the mother may be reflected in behavioral reactivity of infants early in life. These findings set up future studies, which may focus on contributing factors to both dominance and temperament such as genetics, rearing, and socialization. Such factors are likely to interact across development in meaningful ways. These results also suggest future human‐based studies of a similar relationship may be warranted, although social dominance is clearly more complex in human than macaque societies. Am. J. Primatol. 75:65‐73, 2013. Published 2012 by Wiley Periodicals, Inc.?     

The temperature-sensitive mutation vir ts(virilizer) identifies a new gene involved in sex determination of Drosophila

Summary When XX animals homozygous for the temperature-sensitive mutation vir ^tsof virilizer (2–103.9) are raised at the restrictive temperature of 29° C, they are transformed into sterile intersexes with a morphology comparable to XX flies mutant at the sex-determining gene doublesex (dsx). The gonads of the vir ^tsintersexes are ovaries in which the germ cells undergo abortive oogenesis. At the permissive temperature of 25° C or below, XX vir ^tsanimals develop into marginally fertile females. The temperature-sensitive period of vir ^tsis within the third larval instar. XY males are not affected by the mutation. Animals that are homozygous for vir ^tsand either transformer (tra) or tra2 develop as pseudomales; on the other hand, constitutive expression of a female-specific tra product rescues XX animals from the effect of vir ^ts, but these females are sterile. The data show that tra and tra2 are epistatic to vir. Animals with only one wildtype copy of either tra or tra2 and mutant for vir ^tsare already transformed into intersexes at 25° C. Conversely, the presence of three copies of the tra ⁺ gene largely prevents the effect of vir ^tsat 29° C; such flies are practically female, but sterile. Animals homozygous for vir ^tsand heterozygous for dsx ^D/+, raised at 29° C, are transformed into severely masculinized intersexes or almost pseudomales. The observations suggest that vir acts above and via tra and tra2 to achieve proper female-specific expression of the dsx gene in XX zygotes. Offprint requests to: R. Nöthiger     

Minimization of intermediate concentrations as a suggested optimality principle for biochemical networks

The multiobjective problem of minimizing all intermediate concentrations is solved for a model of glycolysis, the pentose monophosphate shunt and the glutathione system in human erythrocytes. It turns out that one solution out of four obtained corresponds qualitatively to the real system. Furthermore, it is shown that for any reaction system, the mentioned optimality principle implies distinct time hierarchy in that some reactions are infinitely fast and subsist in quasi-equilibrium. Finally, the relationships to the standard method of deriving enzymatic rate laws are discussed.