The outflow tract of the heart in fishes: anatomy, genes and evolution

A large number of congenital heart defects associated with mortality in humans are those that affect the cardiac outflow tract, and this provides a strong imperative to understand its development during embryogenesis. While there is wide phylogenetic variation in adult vertebrate heart morphology, recent work has demonstrated evolutionary conservation in the early processes of cardiogenesis, including that of the outflow tract. This, along with the utility and high reproductive potential of fish species such as Danio rerio , Oryzias latipes etc. , suggests that fishes may provide ideal comparative biological models to facilitate a better understanding of this poorly understood region of the heart. In this review, the authors present the current understanding of both phylogeny and ontogeny of the cardiac outflow tract in fishes and examine how new molecular studies are informing the phylogenetic relationships and evolutionary trajectories that have been proposed. The authors also attempt to address some of the issues of nomenclature that confuse this area of research.     

心脏动脉极的形成

目前已发现与生心区形成心管这一过程有密切关系的关键基因和信号分子.对称的生心区后部促使心肌前体细胞形成心脏的流入区域或静脉极.最近在鸡和鼠胚胎中已经鉴定:心肌前体细胞群在咽中胚层中位于早期心管的前部.这种前部导致心脏的流出区域或动脉极处的心肌的产生.因此,脊椎动物的心脏起源于两种心肌前体细胞.这些细胞通过不同的基因程序有规律地出现.心区前部的发现对于解释突变鼠的心脏缺陷和研究人类先天性心脏病有非常重要的意义.     

南极海洋细菌BSw10005生长特性研究

从极地海洋细菌中筛选获得菌株BSw10005,其胞外代谢物质对植物病原真菌有显著的抑制作用。用盐水代替常规的海水米培养极地细菌。在摇瓶中,考察了不同盐浓度、碳源对其生长的影响。利用5L生物反应器,通过改变温度、氧供给条件和控制发酵液pH值,对菌株BSw10005的生长特性作了系统的研究,确定了温度、氧和pH值对菌株生长的影响及菌株培养的最优化的条件。对发酵液中的代谢抑菌活性物质作了初步分离,获得到白色固体粗提物质。     

The different responses of Batocera horsfieldi adults to Juglans regia bark and leaf volatile compounds

Batocera horsfieldi (Hope) (Coleoptera: Cerambycidae) is an important pole borer pest. It causes serious harm to various hosts, particularly Juglans regia L. (Juglandaceae). In this study, headspace solid-phase microextraction (HS-SPME), gas chromatography–mass spectrometry (GC–MS), and electroantennogram (EAG) responses were combined to examine the mechanism by which B. horsfieldi adults locate their host, J. regia. The results showed that J. regia contained 65 volatile compounds in all, with 36 and 42 volatile substances in bark and leaves, respectively. Moreover, terpenes accounted for the largest relative content among the volatile compounds of bark and leaves, 43.4 and 78.9%, respectively. Ten of 19 selected volatile components elicited significant EAG responses in adult B. horsfieldi, which indicated that the pest may prefer certain volatile compounds when selecting a host. Sex and volatile concentration affected the responses of B. horsfieldi. Male adults had the strongest EAG responses to 1-octen-3-ol, whereas female adults had the strongest EAG responses to linalool. Host selection in B. horsfieldi was somewhat positively associated with the concentrations of the effective volatile compounds in the host. Furthermore, B. horsfieldi showed varying preferences for isomers. This work provided data support for the development of insect attractants, and laid a theoretical foundation for the ecological protection of local forestry.     

On the role of glucose in capacitation and acrosomal reaction of guinea pig sperm

In order to determine whether metabolizable sugars delayed capacitation of guinea pig spermatozoa, these cells were pre-incubated in Tyrode's pyruvate lactate glucose medium (T-PLG) or Tyrode's glucose solution (T-G). They were then transferred to minimal culture medium containing pyruvate and lactate (MCM-PL) and the occurrence of acrosomal reactions (AR) was determined by light microscopic observations of wet mount aliquots. The percentage of acrosomal reactions was quantitated in fixed samples and occurrence of a true AR was confirmed by electron microscopy. Activated acrosome-reacted spermatozoa were observed within 5 min when cells were transferred to MCM-PL solution, after preincubating them for 60–120 min either in T-PLG or T-G media. By 15 min in MCM-PL the percentage of acrosome-reacted spermatozoa reached values similar to those obtained in cells pre-incubated from the beginning in MCM-PL medium (P > 0.05 in both) but significantly different from T-PLG and T-G controls (P < 0.0005 in both). The acrosomal reaction was external calcium dependent and independent of the Tyrode's media pH ranging from 7.2 to 8.0. The results obtained suggested that capacitation occurred in T-PLG and that it was not delayed by glucose; the results also suggested that capacitation could occur within a short time with glucose as the only exogenous substrate, but that the acrosome reaction could have been arrested by a glucose metabolite. Data are presented which suggest that intracellular levels of glucose-6-phosphate (as 2-deoxyglucose-6-phosphate)could play a key role in the expression of the acrosome reaction in sperm already able to perform it. A new hypothesis is suggested for the development of the fertilizing potential of guinea pig sperm when in the female genital tract.     

酿酒酵母Sfi1p的结构及生物学功能

纺锤体极体(spindle pole body,SPB)是酵母细胞的微管组织中心,它在细胞分裂及细胞遗传稳定性的维持过程中起着极其重要的作用,是细胞生物学领域热门的研究方向.Sfi1p是酿酒酵母SPB的必需蛋白并且横跨整个半桥,该蛋白与SPB的复制有关,它的缺失或突变会导致SPB复制失败,在哺乳动物的中心体也存在酵母Sfi1p的同源蛋白.本文系统的介绍了酵母Sfi1p及其在人类中心体中的同源蛋白hSfi1p的结构特征,并且阐明了Sfi1p在SPB复制与分离、核配及生孢等细胞周期过程中的作用.对Sfi1p的功能研究,将有助于解决SPB研究过程中重要的科学问题,同时为中心体中Sfi1p同源蛋白的功能研究提供良好的借鉴.     

Mechanisms of genetic instability revealed by analysis of yeast spindle pole body duplication.

Aneuploidy and polyploidy are commonly observed in transformed cells. These states arise from failures during mitotic chromosome segregation, some of which can be traced to defects in the function or duplication of the centrosome. The centrosome is the organizing center for the mitotic spindle, and the equivalent organelle in the budding yeast, Saccharomyces cerevisiae, is the spindle pole body. We review how defects in spindle pole body duplication or function lead to genetic instability in yeast. There are several well documented instances of genetic instability in yeast that can be traced to the spindle pole body, all of which serve as models for genetic instability in transformed cells.     

Ultrastructure of meiosis in the hollyhock rust fungus,Puccinia malvacearum

Summary Changes in the spindle pole body (SPB) and meiotic nuclei from interphase I through interphase II in the hollyhock rustPuccinia malvacearum are analyzed ultrastructurally by three-dimensional reconstructions from serial sections. Interphase I nuclei undergo a coordinated migration and rotation during which the SPBs approach the convex face of the lateral promycelial wall. During the transition from interphase I to prometaphase II, the collateral disc (co-disc) apparently enlarges and fuses with the main disc of the SPB. The resulting single SPB nucleates two confluent half spindles and about 225 astral microtubules (MTs). Co-discs and middle pieces (MPs) are absent during division II. SPBs separate and form metaphase II intranuclear spindles oriented in a predictable manner. Tubular cisternae are present within the spindle at early metaphase II. The architecture of the spindle at division II is essentially identical to that reported for division I except that the spindle is about half as long. Anaphase-telophase II nuclear envelope constriction, separation of the sibling nuclei, and externalization of the SPBs is identical to that reported for division I. Genesis of the duplicated interphase II SPB apparently occurs rapidly and involves formation of the MP followed by the three-layered SPB discs. General aspects of the division II spindle are discussed. A model for the meiotic SPB cycle in a rust is presented and its phylogenetic and functional significance in relation to other basidiomycetes and ascomycetes is discussed.