异育淇鲫及其双亲同工酶的比较研究

用4.5％聚丙烯酰胺凝胶平板电泳研究了异育淇鲫及其母本淇鲫和父本兴国红鲤的肌可溶性蛋白以及肾、肝、眼、背白肌和心等五种组织的乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)和酯酶(EST)。结果发现:异育淇鲫的肌可溶性蛋白以及同工酶的电泳图谱与母本淇鲫相同而与父本兴国红鲤显著不同,因而认为异育淇鲫是淇鲫雌核发育的产物,父本基因对子代基本无影响。在此基础上,本文对异源精子在雌核发育中所起的生物学作用进行了初步探讨。     

Activity patterns and egg production in Coccophagus bartletti, an aphelinid parasitoid of scale insects

ABSTRACT.

• 1 Daily patterns of oviposition and host-feeding were examined in Coccophagus bartletti Annecke & Insley. Females began to host-feed and oviposit during the second or third day after emergence. Thereafter, both activities occurred regularly.
• 2 During long observation periods (5 h) most oviposition (93%) and host-feeding (90%) occurred within the first 3.5 h of wasps first encountering hosts. Experiments demonstrated that levels of activity were low for the rest of the day, and nocturnal oviposition occurred only if wasps had no alternative.
• 3 Dissection of female wasps that had been exposed to hosts, or withheld from them, for given periods of time, revealed that activity levels are governed by egg availability. Dispersal activity may also be influenced by the physiological state of the ovaries.
• 4 Production of a full complement of eggs (at 24±1°C (12 h L) and 18±1°C (12 h D)) took 48h or longer after host-feeding, and if wasps were withheld from hosts and provided with honey, the effects of egg resorption could be detected after about 10 days. Trends in oögenesis and oösorption in C. bartletti females seem not to conform with interpretations of oögenesis-oösorption cycles in other parasitoids.
• 5 The pattern of activity exhibited by C. bartletti females is not inflexible, but the major aspects mentioned above are species-specific. In general, information is needed about daily and hourly patterns of parasitoid oviposition and host-feeding before experiments are designed to test theories of parasitoid behaviour. Interpretation may otherwise rest on assumptions about their physiological condition.

     

Vitellin and vitellogenin concentrations during oögenesis in the first gonotrophic cycle of the house fly,Musca domestica

The house fly, Musca domestica, contains at least two native vitellin and two vitellogenin proteins. Both vitellins appear to have an identical vitellogenin partner. The major native vitellin has a mol. wt of 281 K Daltons, and the major native vitellogenin has a mol. wt of 283 K Daltons. These proteins are composed of three subunits with mol. wt of 48, 45 and 40 K Daltons. The relationship of the subunits to the native proteins is not known.Haemolymph vitellogenin levels are cyclical during oögenesis with no detectable amounts in previtellogenic flies and low levels in postvitellogenic flies. The highest level of vitellogenin, 10.5 μg/μl, occurred in flies with stage-7 ovaries. The vitellogenin levels during oögenesis fit a parabolic curve and the fat body vitellogenin content during oögenesis showed this same pattern.Uptake of vitellogenin into the ovary during each stage of oögenesis also fit a parabolic curve and produced a high linear correlation with haemolymph vitellogenin levels. The greatest uptake was 37 μg/stage and occurred during stage 6.     

Oögenesis in a marine teleost,Blennius pholis L.

Summary Oögenesis in the oviparous marine teleost, Blennius pholis L., is examined. Eleven developmental stages are identified by ultrastructural observations when changes in the distributions of the organelles and inclusions are described. An exogenous source for the protein yolk precursors is indicated, but less clear is the endogenous contribution. Changes in the follicle epithelium are described together with the formation of the zona which is considered to be follicular in origin. Two types of follicle cell are distinguished and these probably function differently in the process of zona formation. The zona becomes divided into the externa and interna, the latter probably resulting from the chemical ordering by disulphide bonding of the proteinaceous material of the former.We are indebted to Professor E.W. Knight-Jones in whose department the work was carried out, and to the Natural Environment Research Council for support for one of us (S.E.S.).     

Endocrine influence upon the development of vitellogenic competency in Oncopeltus fasciatus

Immunoelectrophoretic analysis of the blood of precocious adult females of Oncopeltus demonstrated the presence of the A form of vitellogenin but no detectable AB form, the form present in mature adult-female haemolymph. Although the appearance of the AB form could be induced by topical treatment of precocious adult females with juvenile hormone, no yolk deposition was induced in these females. Histological examination revealed that the ovaries of precocious adult females reached only a previtellogenic stage of development with or without treatment with juvenile hormone. Topical treatment of normal larvae and adults with the hormone demonstrated that vitellogenin synthesis could not be induced with juvenile hormone treatment alone until after adult emergence. Since the precocious adult females are chronologically younger than normal last-stage larval instars, we suggest that a transition period during which juvenile hormone is absent (i.e. the precocious moult in treated animals; the final moult in control animals) must occur before some tissue of the precocious or normal adult females, presumably the fat body, becomes competent to respond to further exposure to the hormone by making the AB form of vitellogenin. The ovary requires a similar transition period prior to becoming capable of depositing vitellogenin; however, the times when the fat body and the ovary become competent to respond to the transition period differ.     

The identification and titres of conjugated and free ecdysteroids in developing ovaries and newly-laid eggs of Schistocerca gregaria

Ecdysteroid levels throughout ovarian development and in newly-laid eggs of S. gregaria have been determined. A simple method for the separation of free and conjugated ecdysteroids is described. Both free and polar conjugated ecdysteroids are present at the end of oögenesis and in newly-laid eggs, but the polar conjugated ecdysteroids always predominate; 95% of the total ecdysteroid in newly-laid eggs is in the conjugated form. Ecdysone, 2-deoxyecdysone and 20-hydroxyecdysone have been fully characterized from both the ‘free’ and ‘conjugated’ fractions. The presence of traces of 26-hydroxyecdysone in the ‘conjugate’ fraction was indicated by HPLC analyses. The levels of ecdysteroid released from the conjugates of newly-laid eggs were 35 μg/egg pod (44 μg/g wet weight) for ecdysone, 16 μg/egg pod (19.4 μg/g) for 2-deoxyecdysone and 5 μg/egg pod (6.1 μg/g) for 20-hydroxyecdysone. The level of free ecdysone found in newly-laid eggs was 2 μg/egg pod (2.6 μg/g).     

Development and physiology of follicular atresia during ovarian growth in the house fly, Musca domestica

Atretic follicles regularly occur in the ovary of the house fly, Musca domestica. The frequency of ovarian follicular atresia and the proportion of atretic follicles per ovary are related to the stage of oögenesis and to the age of the females. Only vitellogenic follicles may become atretic. The atresia may occur at any stage of vitellogenesis, though most follicles become atretic in mid-vitellogenesis. Atretic follicles are completely resorbed within 24–36 hr. The follicle cells may play a synthesizing role during growth and disintegrating one during follicle resorption. The induction of glycogen synthesis by the cessation of RNA and protein synthesis and by vitellogenesis in normal follicles is discussed. The same processes occur prematurely in the atretic follicle which can be thus distinguished by a high content of glycogen.     

Reassessment of the Microbial Role in Mn-Fe Nodule Genesis in Andean Paleosols

The presence of Mn-Fe nodules in the epipedons (surface horizons) of paleosols of presumed Upper Neogene age in the northwestern Venezuelan Andes have been interpreted as products of inorganic oxidation and reduction processes operating over the full range of glacial and interglacial cycles that affected paleosol morphogenesis. New microscopic/chemical data from combined SEM-EDS-FIB analyses of representative Mn-Fe nodules indicate microbes play an important role in Mn/Fe precipitation leading to their genesis in alpine Mollisols (Argiustolls). Although the prevailing new data are based mainly on fossil forms of filamentous bacteria and fungi and other biogenic pseudomorphs that may represent the former resident bacteria, the presence of extant microbes must await field experiments/collection, followed by a molecular microbiology approach to determine the biological drivers of metal precipitation. As in other terrestrial niche environments, microbes are seen here to play a role, perhaps a key one, in the morphogenesis of paleosols of importance in upper Neogene paleoenvironmental reconstruction.     

On phylogenetic inertia: a case of Lixinae weevils

Summary. Among host plants of Lixinae weevils, plant life-form ratio (sensu Raunkiaer) is similar to the plant spectrum of Mediterranean deserts. A possible explanation is that this group of insects formed in desert zones and settled in the steppe rather later. For the first time Raunkiaer’s life-form ratio is compared with a spectrum of food plants of herbivores. This approach may be useful for reconstruction of the genesis of taxa and communities.     

抑制肿瘤生长活性的内皮生长抑制剂EDI-8t

对内源性的内皮生长抑制剂的序列来源分析后,用RT-PCR方法从人脐带中获得了417bp的cDNA,并克隆到毕赤酵母表达载体pPIC9,然后转化毕赤酵母GS115获得重组表达菌株。表达菌株通过甲醇诱导表达后,将发酵液通过分离纯化获得重组蛋白纯品,命名为EDI-8t。体外实验结果表明,这个胶原蛋白VIII来源的rhEDI-8t蛋白能特异性地抑制牛主动脉内皮细胞的增殖和迁移,并能引起内皮细胞的凋亡。动物体内实验结果表明,rhEDI-8t蛋白样品可有效抑制裸鼠皮下肝癌肿瘤的生长,抑制效果和参照品endostatin相同。但在小鼠黑色素瘤肺转移模型中,rhEDI-8t显示了高于参照品的抑癌效果。