Sox1基因在爪蟾早期发育中的时空表达图式

克隆了非洲爪蟾的Sox1基因并研究了它在非洲爪蟾早期发育过程中的时空表达图式,比较了Sox1—3基因在发育的脑和眼中的表达图式。序列比对分析显示Sox1—3蛋白在其HMG框结构域具有高度的保守性。通过RT-PCR方法分析了Sox1基因在爪蟾早期不同发育时段的表达情况,结果显示Sox1基因从未受精卵到尾芽期均有表达,但表达强度有所差异。原位杂交结果显示,在早期卵裂阶段和囊胚期,Sox1基因主要在动物极表达;从神经板期开始,Sox1基因主要在中枢神经系统和眼原基中表达。在蝌蚪期,Sox1与Sox2、Sox3在脑部和眼睛的表达区域有所不同。对于爪蟾Sox1基因时空表达图式的研究将有助于阐明SoxB1基因家族在脊椎动物神经系统发生过程中的作用。     

ADAM19 在小鼠睾丸发育中的时空表达

目的 阐明含有去整合素和金属蛋白酶结构域的跨膜蛋白19(ADAM19)在小鼠睾丸发育中的作用.方法 采用半定量RT-PCR和免疫组化两种实验方法,分别检测ADAM19 mRNA和蛋白质在小鼠睾丸发育中的时空表达.结果 ①最早在胚胎发育的15.5 d才能检测到ADAM19 mRNA的表达,后其表达随着胚胎发育天数的增加而逐渐升高,到围产期表达水平达到最高.出生后,ADAM19 mRNA的表达呈现显著下降的趋势,到成体睾丸中就几乎检测不到ADAM19的表达.②和其mRNA表达变化趋势一样,ADAM19蛋白也是首次在胚胎发育的15.5 d被检测到,一直持续存在到出生后一周,一周后则几乎检测不到;阳性表达信号主要定位在睾丸的曲细精管(睾索)中.结论 ADAM19 在小鼠睾丸中的表达具有显著的发育依赖性.     

Spatial and Temporal Variations in Chitinolytic Gene Expression and Bacterial Biomass Production during Chitin Degradation

Growth of the chitin-degrading marine bacterium S91 on solid surfaces under oligotrophic conditions was accompanied by the displacement of a large fraction of the surface-derived bacterial production into the flowing bulk aqueous phase, irrespective of the value of the surface as a nutrient source. Over a 200-h period of surface colonization, 97 and 75% of the bacterial biomass generated on biodegradable chitin and a nonnutritional silicon surface, respectively, detached to become part of the free-living population in the bulk aqueous phase. Specific surface-associated growth rates that included the cells that subsequently detached from the substrata varied depending on the nutritional value of the substratum and during the period of surface colonization. Specific growth rates of 3.79 and 2.83 day⁻¹ were obtained when cells first began to proliferate on a pure chitin film and a silicon surface, respectively. Later, when cell densities on the surface and detached cells as CFU in the bulk aqueous phase achieved a quasi-steady state, specific growth rates decreased to 1.08 and 0.79 day⁻¹ on the chitin and silicon surfaces, respectively. Virtually all of the cells that detached from either the chitin or the silicon surfaces and the majority of cells associated with the chitin surface over the 200-h period of surface colonization displayed no detectable expression of the chitin-degrading genes chiA and chiB. Cells displaying high levels of chiA-chiB expression were detected only on the chitin surface and then only clustered in discrete areas of the surface. Surface-associated, differential gene expression and displacement of bacterial production from surfaces represent adaptations at the population level that promote efficient utilization of limited resources and dispersal of progeny to maximize access to new sources of energy and maintenance of the population.     

Temporal and Spatial Expression of the {alpha}-Amylase Gene during Seed Germination in Rice and Barley

We have analyzed the in situ hybridization of     

Tenascin-r基因在斑马鱼胚胎发育中时空表达规律

Tenascin-r(TNR)是一种脊椎动物细胞外基质糖蛋白,在不同的物种间具有高度保守性,主要表达于神经系统,通过调节基质粘附状态和基质间相互作用而促进细胞的迁移、增殖和分化.在小鼠等动物模型中,TNR在中枢神经系统的发育中起重要作用,能控制大脑活动、调节适应性行为.而在斑马鱼研究中,TNR仅在视神经的发育和修复中起作用,通过对TNR在斑马鱼胚胎发育时期时空表达规律的研究,可以为利用斑马鱼进一步研究TNR的功能建立一个平台.     

Temporal Patterns of Gene Expression in the Antenna of the Adult Drosophila Melanogaster

The time course of gene expression in the adult fruit fly has been partially characterized by using enhancer trap and reporter gene constructs that mark 49 different genes. The relative intensity of the reporter protein in individual cells of the antennae was measured as a function of adult age. Most genes showed a graduated expression, and the intensity of expression had a reproducible and characteristic time course. Different genes displayed different temporal patterns of expression and more often than not the pattern of expression was complex. We found a number of genes having patterns that scaled with life span. In these cases the intensity of gene expression was found to be invariant with respect to biological time, when expressed as a fraction of the life span of the line. The scaling was observed even when life span was varied as much as threefold. Such scaling serves to (1) further demonstrate that deterministic mechanisms such as gene regulation act to generate the temporal patterns of expression seen during adult life, (2) indicate that control of these regulatory mechanisms is linked to life span, and (3) suggest mechanisms by which this control is accomplished. We have concluded that gene expression in the adult fly is often regulated in a fashion that allows for graduated expression over time, and that the regulation itself is changing throughout adult life according to some prescribed program or algorithm.     

Heat-Induced Changes in Thermosensitivity and Gene Expression during Development

The thermosensitivity of developing embryos of the fresh water snail Lymnaea stagnalis was investigated from the 4-cell stage to the 3-day-old trochophore larva by means of survival curves for 43.6°C. Cleavage stage embryos were extremely thermoresistant as compared with older stages, and thermosensitivity increases during the development.
Pretreatment with a mild heat exposure (10 min at 39°C) did not induce thermotolerance at the 4-cell stage, but it did so in the early gastrula and trochophora. Development of thermotolerance in 1-, 2-, and 3-day-old stages showed an identical kinetic pattern.
After incubation in ³⁵S-methionine one-dimensional gel electrophoresis was carried out with or without preheating. At the 4-cell stage no enhanced synthesis of heat shock proteins was induced by exposure to heat. At stages of 1 day and older heat induced the enhanced synthesis of the heat shock proteins with apparent molecular weights of 38, 65 and 70 kilodaltons. The synthesis of heat shock protein 70 changes during the early development of Lymnaea both in its constitutive level and in its ability to be enhanced by heat treatment.