青藏高原动物地理区的地位和东部界线问题

本文从历史时空的角度分析了青藏高原地区发生的鱼类区系的变化过程,和高原鱼类区系演化的相对独立性,认为这一鱼类区系的分化直接反映了高原隆升事件,并应当在动物地理区划上得到客观反映,即将青藏高原作为一个独立的区划单元。由于青藏高原的隆升和造成古北区、东洋区分化的第三纪末、第四纪初的全球性气候变冷在时间上相近、波及的范围都巨大,共同促成了欧亚大陆古北区、东洋区和青藏高原区特有类群的分化,作为对这些地史事件反映的青藏高原区、古北区和东洋区,在动物地理区划上应该具有相同的地位．另外,依据高原鱼类的分布范围和青藏高原对非高原鱼类的阻碍作用,讨论了青藏高原的界限及其划分问题。     

Tail raising by baboon mothers toward immigrant males

Behavioral responses of adult females to recently immigrated adult males were examined in two groups of chacma baboons in the Moremi Wildlife Reserve, Botswana. Mothers carrying infants respond negatively by raising their tails, avoiding, and screaming when in proximity to immigrant males. These responses are not given by mothers when their infants are away from them or by females who do not have infants. Also, the negative responses by mothers carrying infants are given only to immigrant males and not to long-term resident males. These observations are in concordance with the growing evidence of infanticide in savanna baboon societies: mothers would be expected to show negative responses to potentially aggressive males, particularly immigrants. There was evidence to suggest that mothers respond negatively to immigrants only insofar as these males could not have sired their infants. If confirmed by subsequent observations, this result would lend support to the sexual selection model of infanticide.     

Genetic analysis of transpositions in the lac region of Escherichia coli

The lac region of Escherichia coli, carried on an F′ lacproB episome, was used as a target for the transposition of several transposable elements. Tn9 shows a preferential integration (by a factor of 50) into a region extending from the end of the Z gene through the Y gene. Throughout the remainder of the lacI, Z and Y genes one other short region, located in the middle of the I gene, is favored for integration. Within these favored regions many different integration points are evident. Inspection of the DNA sequence for the I and Y genes, and parts of the Z gene, shows a strong correlation between A + T richness and regions of preferential integration. Tn5 insertions follow a similar pattern, although with less preference; whereas Tn10 insertions (provided by T. J. Foster), also favor the Y gene and the end of Z, but are distributed among fewer integration points. Most of the Tn3 insertions into the episome are accompanied by a nearby or adjacent deletion.     

祁连山东段高寒植被群落特征及其与地形气候因子关系研究

地形气候因子与物种分布的关系影响着高寒植被群落的演替,同时对山地水源涵养林功能和结构的维持具有重要的意义。以祁连山东段水源涵养林为研究对象,基于野外植物群落物种组成及地形气候因子调查数据,运用数量分类与排序等方法,探究了高寒植物群落特征及其与地形气候因子的关系。结果表明:65个调查样方中出现181个植物种,隶属40科,124属。科的物种组成及占总物种数比例分别为菊科30个种,占16.57%;蔷薇科17个,占9.44%;禾本科13个种,占7.22%;豆科11个种,占6.11%。毛茛科10个种,占5.56%。单属种82个,占总属数的66.13%。群落层片由乔木层、灌木层和草本层组成,乔木8种,灌木25种,草本148种。乔木层优势种有青海云杉、祁连圆柏、红桦。灌木层优势种有金露梅、山生柳、匙叶小檗、高山绣线菊。草本层优势种有甘肃薹草、珠芽蓼、早熟禾、唐松草、甘青蒿。TWINSPAN将高寒植被群落划分为7个群丛类型:群丛I红桦-红花蔷薇-甘肃薹草B.albosinensis-Rosa moyesii-C.kansuensis,群丛II青海云杉-匙叶小檗-甘肃薹草P.crassifolia-B.vernae-C.kansuensis,群丛III祁连圆柏-高山绣线菊-珠芽蓼Sabina chinensis-Spiraea alpine-P.viviparum,群丛IV高山绣线菊+鬼箭锦鸡儿-珠芽蓼S.alpine+Caragana jubata-P.viviparum,群丛V沙棘+甘青蒿+鼠掌老鹳草Hippophae rhamnoides+A.tangutica+Geranium sibiricum,群丛VI沙棘+苦荬菜+苦荞麦H.rhamnoides+Ixeris polycephala+Fagopyrum tataricum,群丛VII沙棘-冰草+西北沼委陵菜H.rhamnoides-Agropyron cristatum+Comarum salesovianum。7个群丛在DCA排序图上聚集分布,反映了较好的环境梯度。CCA排序结果表明,海拔是祁连山高寒植被群落植物种分布的最重要环境因子,其次是降水、温度、坡向、坡度。     

Microscale grooves regulate maturation development of hPSC-CMs by the transient receptor potential channels (TRP channels)

The use of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is limited in drug discovery and cardiac disease mechanism studies due to cell immaturity. Micro-scaled grooves can promote the maturation of cardiomyocytes by aligning them in order, but the mechanism of cardiomyocytes alignment has not been studied. From the level of calcium activity, gene expression and cell morphology, we verified that the W20H5 grooves can effectively promote the maturation of cardiomyocytes. The transient receptor potential channels (TRP channels) also play an important role in the maturation and development of cardiomyocytes. These findings support the engineered hPSC-CMs as a powerful model to study cardiac disease mechanism and partly mimic the myocardial morphological development. The important role of the TRP channels in the maturation and development of myocardium is first revealed.     

Studies on the regioselectivity and kinetics of the action of trypsin on proinsulin and its derivatives using mass spectrometry

Human M-proinsulin was cleaved by trypsin at the R³¹R³²–E³³ and K⁶⁴R⁶⁵–G⁶⁶ bonds (B/C and C/A junctions), showing the same cleavage specificity as exhibited by prohormone convertases 1 and 2 respectively. Buffalo/bovine M-proinsulin was also cleaved by trypsin at the K⁵⁹R⁶⁰–G⁶¹ bond but at the B/C junction cleavage occurred at the R³¹R³²–E³³ as well as the R³¹–R³²E³³ bond. Thus, the human isoform in the native state, with a 31 residue connecting C-peptide, seems to have a unique structure around the B/C and C/A junctions and cleavage at these sites is predominantly governed by the structure of the proinsulin itself. In the case of both the proinsulin species the cleavage at the B/C junction was preferred (65%) over that at the C/A junction (35%) supporting the earlier suggestion of the presence of some form of secondary structure at the C/A junction. Proinsulin and its derivatives, as natural substrates for trypsin, were used and mass spectrometric analysis showed that the k_cat./K_m values for the cleavage were most favourable for the scission of the bonds at the two junctions (1.02 ± 0.08 × 10⁵ s^− 1 M^− 1) and the cleavage of the K²⁹–T³⁰ bond of M-insulin-RR (1.3 ± 0.07 × 10⁵ s^− 1 M^− 1). However, the K²⁹–T³⁰ bond in M-insulin, insulin as well as M-proinsulin was shielded from attack by trypsin (k_cat./K_m values around 1000 s^− 1 M^− 1). Hence, as the biosynthetic path follows the sequence; proinsulin → insulin-RR → insulin, the K²⁹–T³⁰ bond becomes shielded, exposed then shielded again respectively.     

Zebra: a web server for bioinformatic analysis of diverse protein families

During evolution of proteins from a common ancestor, one functional property can be preserved while others can vary leading to functional diversity. A systematic study of the corresponding adaptive mutations provides a key to one of the most challenging problems of modern structural biology – understanding the impact of amino acid substitutions on protein function. The subfamily-specific positions (SSPs) are conserved within functional subfamilies but are different between them and, therefore, seem to be responsible for functional diversity in protein superfamilies. Consequently, a corresponding method to perform the bioinformatic analysis of sequence and structural data has to be implemented in the common laboratory practice to study the structure–function relationship in proteins and develop novel protein engineering strategies. This paper describes Zebra web server – a powerful remote platform that implements a novel bioinformatic analysis algorithm to study diverse protein families. It is the first application that provides specificity determinants at different levels of functional classification, therefore addressing complex functional diversity of large superfamilies. Statistical analysis is implemented to automatically select a set of highly significant SSPs to be used as hotspots for directed evolution or rational design experiments and analyzed studying the structure–function relationship. Zebra results are provided in two ways – (1) as a single all-in-one parsable text file and (2) as PyMol sessions with structural representation of SSPs. Zebra web server is available at http://biokinet.belozersky.msu.ru/zebra.