The spatial arrangement of germ line cells in ovarian follicles of the mutantdicephalic inDrosophila melanogaster

Summary The pattern of intercellular connections between germ line cells has been studied in follicles of the mutantdicephalic (dic), which possess nurse cell clusters at both poles. Staining of follicles with a fluorescent rhodamine conjugate of phalloidin reveals ring canals and cell membranes and thus allows us to reconstruct the spatial organization of the follicle. Each germ line cell can be identified by the pattern of cell-cell connections which reflect the mitotic history of individual cells in the 16-cell cluster. The results indicate that in both wild-type anddicephalic cystocyte clusters one of the two cells with four ring canals normally becomes the pro-oocyte. However, in some follicles (dicephalic and wild-type) oocytes were found with fewer or more than four ring canals. Indic follicles, one or several nurse cells may become disconnected from the other cells during oocyte growth at stage 9–10. Such disconnected cells cannot later on empty their cytoplasm into the oocyte. This, in turn, might be of consequence for the determination of axial polarity of the embryo.     

Cation-distribution in developing follicles of the fruit fly Drosophila melanogaster

Abstract. Cations were precipitated with potassium antimonate in ovarian follicles of Drosophila and the distribution of the formed precipitates was studied. The precipitates were analyzed with a laser microprobe mass analyzer (LAMMA) and found to contain a high concentration of calcium; potassium and sodium were also detected. On counting the antimon precipitates in stage 10B follicles with the electron microscope, few precipitates per unit area were found in anterior nurse cells, but more in posterior nurse cells; the highest precipitate density occurred consistently in the oocyte. When follicles of different stages were compared, the precipitate density was found to increase in the ooplasm and in the posterior nurse cells during vitellogenesis, whereas it remained nearly constant in the anterior nurse cells. Thus, the ratio of precipitates between the posterior and anterior end of the follicle increases during vitellogenesis. It begins to decrease at the time when the nurse cells collapse. These results suggest that the electrical polarity observed in polytrophic ovarioles may be based on differences in the cation distribution along the antero-posterior axis of the follicle.     

Evidence against electrophoresis as the principal mode of protein transport in vitellogenic ovarian follicles of Drosophila

Charged cell constituents in polytrophic insect follicles are thought to be transported in the nurse cell-oocyte syncytium by way of electrophoresis. This concept, proposed by Woodruff & Telfer (1980) was based on electrophysiological data and microinjection of heterologous proteins using Hyalophora follicles. By microinjecting fluorescently labelled acidic and basic proteins into the nurse cells or oocyte of vitellogenic Drosophila follicles, we failed to obtain evidence for charge-dependent migration of these molecules. We have also analyzed the proteins of nurse cells and oocyte on isoelectric focusing gels, by means of two-dimensional gel electrophoresis, and by ion exchange chromatography to see if basic or acidic proteins accumulate in vivo in nurse cells and oocyte, respectively. For the bulk of the follicular proteins we found no accumulation. Further evidence against an electrophoretic transport system in Drosophila was obtained by estimating the intracellular pH from the colour of indicator dyes microinjected into the follicles; the results indicate that the pH in the nurse cell cytoplasm is lower than that in the ooplasm. According to the model developed for Hyalophora, electrophoretic transport would be favoured by high pH in the nurse cell cytoplasm.     

刺激家兔颈交感神经对颈动脉窦反射的影响

在36只麻醉家兔观察了电刺激颈交感神经(CSN)对颈动脉窦压力感受器(CSB)活动的影响。所得结果如下:(1)电刺激 CSN 可使夹闭颈动脉引起的加压反射消失或倒转,△BP 从刺激前的 39.5±3.6mmHg 变为刺激时的-0.31±5.4mmHg(P<0.001)。(2)在电刺激CSN 时,静注新福林所诱发的颈动脉窦压力感受器-心率反射增强,表现为反射性心率减慢较刺激前更为明显。(3)在以50—200mmHg 的压力充胀两侧颈动脉窦的条件下,刺激 CSN 引起窦内压与平均动脉压的关系曲线下移,与刺激前曲线相比有明显差异(P<0.01)。(4)切断 CSN 后,动脉血压有所升高,提示 CSN 对 CSB 活动有紧张性调节作用。以上结果比较明确地表明家兔 CSN 对 CSB 活动有调节作用。此作用可能是 CSN 作用于窦壁平滑肌而间接引起的。     

Net Accumulation of Minerals and Water and the Carbon Budget in an Expanding Leaf of Tomato

The changes in f. wt, d. wt, nitrogen, potassium, calcium, phosphorus,magnesium and carbon of the seventh leaf of a tomato plant weremeasured at seven occasions from 10 days to 30 days after leafemergence. Measurements of CO₂ exchange by the leaf during bothlight (70 W m^–2, 7 h) and dark (17 h) periods and thechange in carbon content over these two periods enabled a carbonbalance to be constructed on these seven occasions. Changesin the sugars and starch contents of the leaf over these twoperiods at each occasion were measured. With the exception of calcium the rates of accumulation of allsubstances increased to their maxima when the leaf was 22–24-days-old.Carbon fixation per unit f. wt. increased to a maximum whenthe leaf was 16-days-old. In a 10-day-old leaf the rate of carbonfixation was already four-fifths of maximum and one-quartermore than that at 30 days. The rate of night respiratory lossof carbon per unit fresh weight decreased as the leaf expanded.In a 10-day-old leaf, the amount of carbon lost by night respirationaccounted for one-quarter of that fixed in the same day. Thisfraction fell to one-tenth when the leaf was 22-days-old andremained constant thereafter. The amount of carbon being importedto the leaflets of a 10-day-old leaf was less than one-quarterof that accumulated in 1 day. Thus, the contribution of theimported carbon to the leaf growth up to this stage is relativelysmall. The transition of the seventh leaf from being a net importerto being a net exporter occurred when the leaf was 13-days-old. The sucrose content per unit f. wt was higher in the youngerthan in the older leaves and was not correlated to the transitionfrom net import to net export. The accumulation and breakdownof starch in a leaf were related not only to the growth of theleaf but also to the development of the whole plant. Lycopersicon esculentum, tomato, leaf, accumulation of minerals, water content, carbon budget     

夜蛾趋光特性的研究:复眼转化过程中的行为变异

影响蛾类趋光性和灯光诱蛾效果的因素很多。过去,国内外许多观察和实验都侧重在研究光源的辐射光谱和辐射强度以及气候条件的影响。至于蛾类的主要感光器官的适应状态怎样影响趋光性,却极少引起注意。 陈元光等(1963)曾经用电生理学的方法,测出粘虫蛾复眼的暗适应过程大约为30—45分钟。Agee(1972)用电生理方法研究复眼,发现美国棉铃虫复眼在暗适应中,达到最高灵敏度的时间为30分至285分,雌、雄的平均时间分别为88分和115分;美国烟青虫雌、雄蛾的平均时间分别为119分和121分。最近,李典谟等(1977)以复眼反射光的增强作为暗适应的指标,测出烟青虫蛾在暗室内暗适应时,复眼的转化速率很不一致。快的个体约经过1小时就达到最大反射值;慢的个体则需经过3小时,而绝大多数个体(79％)则在1—2(1/2)小时内。因此,他们推测在入夜后的一段时间里,田间昆虫的眼由昼眼转化为夜眼的情况是各不相同的,并且认为这种差异会影响成虫对于灯光发生不同的行为反应。棉铃虫(Heliothis armigera)蛾是灯光防治的主要对象之一,为了进一步探索这个问题,我们认为有必要检查一下在日夜交替的自然暗适应条件下其复眼状态究竟是否一致,复眼状态怎样影响着趋光性,以便深入地了解夜蛾类趋光性的控制因素。     

Localized synthesis of specific proteins during oogenesis and early embryogenesis inDrosophila melanogaster

Summary Protein synthesis in egg follicles and blastoderm embryos ofDrosophila melanogaster has been studied by means of two-dimensional gel electrophoresis. Up to 400 polypeptide spots have been resolved on autoradiographs. Stage 10 follicles (for stages see King, 1970) were labelled in vitro for 10 to 60 min with³⁵S-methionine and cut with tungsten needles into an anterior fragment containing the nurse cells and a posterior fragment containing the oocyte and follicle cells. The nurse cells were found to synthesize a complex pattern of proteins. At least two proteins were detected only in nurse cells but not in the oocyte even after a one hour labelling period. Nurse cells isolated from stages 9, 10 and 12 follicles were shown to synthesize stage specific patterns of proteins. Several proteins are synthesized in posterior fragments of stage 10 follicles but not in anterior fragments. These proteins are only found in follicle cells. No oocyte specific proteins have been detected. Striking differences between the protein patterns of anterior and posterior fragments persist until the nurse cells degenerate. In mature stage 14 follicles, labelled in vivo, no significant differences in the protein patterns of isolated anterior and posterior fragments could be detected; this may be due to technical limitations. At the blastoderm stage localized synthesis of specific proteins becomes detectable again. When blastoderm embryos, labelled in vivo, are cut with tungsten needles and the cells are isolated from anterior and posterior halves, differences become apparent. The pole cells located at the posterior pole are highly active in protein synthesis and contribute several specific proteins which are found exclusively in the posterior region of the embryo. In this study synthesis of specific proteins could only be demonstrated at those developmental stages which are characterized by the presence of different cell types within the egg chamber, while no differences were detected when stage 14 follicles were cut and anterior and posterior fragments analyzed separately. The differences in the pattern of protein synthesis by pole cells and blastoderm cells indicate that even the earliest stages of determination are reflected by marked changes at the biochemical level.     

广州地区中华按蚊生理年龄的组成

中华按蚊是我国平原地区的传疟媒介,研究中华按蚊的生态学,对于疟疾的流行病学及预防均具有重要的意义。生理年龄及生殖营养环的研究,不但可以进一步认识中华按蚊在自然界的一些生态学问题,更重要的是有助于分析其传疟的作用,作为防制的依据。     

Phylogeny of the Homalotina (Coleoptera: Staphylinidae: Aleocharinae) based on morphology

The aleocharine subtribe Homalotina Heer represents one of the most diverse lineages of Staphylinidae. Despite its wide distribution and diversity, the phylogenetic relationships of the subtribe remain poorly understood. Here, we present the first cladistic analysis of the Homalotina based on morphological data. The subtribe is hypothesized to be a monophyletic group consisting of seven genera (Anomognathus Solier, Cephaloxynum Bernhauer, Holisomimus Cameron, Homalota Mannerheim, Neomalota Cameron, Stenomastax Cameron, and Thecturota Casey). The dataset for phylogenetic analysis comprised 83 characters representing 245 character states derived from adult morphology. These data were analysed using equal weighting and implied weighting schemes (k = 1–6) and results support the monophyly of the subtribe based on two synapomorphic characters (complete postoccipital sutures on head, posterolateral margin of metacoxae with macrosetae) and three homoplastic characters (medial setae on prementum not extended to apex of ligula, medial setae on labium contiguous, posterolateral angle of elytron slightly sinuate). Generic relationships differ in each analysis within the Homalotina (EW, IW with k = 1, 2–4, 5–6) although there are some identical topologies among the IW trees. Clades A, B, C, D, H, J and G were resolved as monophyletic in all weighting regimes. The monophyly of the genera is relatively well supported except for the genera Homalota and Stenomastax. Homalota species were recovered in four independent clades (clade C, D, I, K) and the Stenomastax species were recovered in two independent lineages. Candidates for the possible new genera are discussed. We herein transfer Homalota flavomaculata Bernhauer to the genus Stenomastax, resulting in the new combination [Stenomastax flavomaculata (Bernhauer)]. Our preliminary character correlation tests using phylogenetic pairwise comparisons did not support the hypothesis of association between flattened body form, and subcortical habitat and anterior shift of antennal insertion in Homalotini.     

心房钠尿因子对麻醉家兔局部血流的影响

在42只麻醉家兔,观察了静脉注射心房肽Ⅱ(AtriopeptinⅡ,APⅡ)对局部血流量以及动脉内注射 AP Ⅱ 对局部血管阻力的影响。结果如下:(1)静脉注射 APⅡ(30μg/kg)5min后,平均动脉压(MAP)降低11.0±1.5mmHg(n=8,M±SE,下同),与溶剂对照组相比有明显差异(P相似文献