胚珠组织的实验操作

1984年9月24—28日在英国伦敦大学召开了一次题为“胚珠组织的实验操作——显微操作、组织培养与生理学”的国际学术讨论会,与会各国学者约50人,我国周光宇教授也应邀出席并作了报告。会后编辑出版了文集《胚珠组织的实验操作》(The Experi-     

花粉原生质体,精子与生殖细胞的实验操作

当前,一个可以称为“植物实验生殖生物学”的分支学科正在形成之中。其主要特点是:由以往实验胚胎学的器官、组织水平的操作发展为细胞、原生质体水平的操作;由传统的比较单一的研究发展为多学科的综合性研究;因而无论在研究的手段与内容方面均进入更高的层次。例如,就雄性系统而言,已由花药培养发展到花粉粒培养,最近又向花粉原生质体、精子和生殖细胞的操作深化。就雌性系统而言,亦由子房、胚珠培养向胚     

EXPERIMENTAL MANIPULATION OF ALTERNATIVE PATHWAYS OF DIFFERENTIATION IN CULTURES OF EMBRYONIC CHICK NEURAL RETINA

Embryonic chick neural retina cells can transdifferentiate during long-term cell culture into either pigmented epithelium or lens fibres. We have found that some culture conditions influence the choice between these pathways. Pigment cell development is promoted by low initial cell densities and by the use of a medium based on Earle's salt formulation rather than Hank's, while lens fibre development is encouraged by high initial cell densities and by folding the cell sheet into multilayered regions. Some differences in in vitro cell properties of neural retina are reported for two genotypes previously found to exhibit differences in in vitro cell properties of lens epithelial cells.     

EXPERIMENTAL CONTROL OF FRUIT-BODY FORMATION IN COPRINUS MACRORHIZUS

In order to establish a proper experimental system for studying the physiological and biochemical processes of fruit-body formation in a Basidiomycetes, Coprinus macrorhizus Rea f. microsporus Hongo, various culture conditions, especially light and temperature, were investigated. The use of homogenates of fruit-body primordia, instead of mycelia, as inocula was effective for maintaining cultures capable of active fruit-body formation during many successive cultivations. At least two successive intermittent illuminations every 12 hr during the 3rd and 4th days of incubation were required for the differentiation of pilei. The most effective wave lengths of incident light were found in the region from 440 to 485 mμ. Temperature effects on fruit-body formation were exhibited in two stages of morphogenesis; i.e., in the induction of primordia formation from vegetative hyphae (by 5°-treatment) and in the transition phase from primordia formation to fruit-body development (by 20°-treatment). Based on these observations, three experimental systems for physiological and biochemical studies on the fruit-body formation have been proposed.     

激光对生物粒子的操纵

本文介绍了有关激光操纵生物粒子研究进展,包括用单光束梯度力陷阱俘获生物细胞,对细胞内细胞器以及对单个生物大分子进行操纵等的研究,文章最后指出激光陷阱将被作为一种“光学镊子”来自由地操纵和研究单个生物大分子,从而为分子生物学,生物分子工程提供一个崭新的研究手段。     

EXPERIMENTAL MANIPULATION OF SEXUAL SELECTION PROMOTES GREATER MALE MATING CAPACITY BUT DOES NOT ALTER SPERM INVESTMENT

Sexual selection theory makes clear predictions regarding male spermatogenic investment. To test these predictions we used experimental sexual selection in Drosophila pseudoobscura , a sperm heteromorphic species in which males produce both fertile and sterile sperm, the latter of which may function in postmating competition. Specifically, we determined whether the number and size of both sperm types, as well as relative testis mass and accessory gland size, increased with increased sperm competition risk and whether any fitness benefits could accrue from such changes. We found no effect of sexual selection history on either the number or size of either sperm morph, or on relative testis mass. However, males experiencing a greater opportunity for sexual selection evolved the largest accessory glands, had the greatest mating capacity, and sired the most progeny. These findings suggest that sterile sperm are not direct targets of sexual selection and that accessory gland size, rather than testis mass, appears to be an important determinant of male reproductive success. We briefly review the data from experimental sexual selection studies and find that testis mass may not be a frequent target of postcopulatory sexual selection and, even when it is, the resulting changes do not always improve fitness.     

EXPERIMENTAL MANIPULATION OF PUTATIVE SELECTIVE AGENTS PROVIDES EVIDENCE FOR THE ROLE OF NATURAL ENEMIES IN THE EVOLUTION OF PLANT DEFENSE

Although biologists have long assumed that plant resistance characters evolved under selection exerted by such natural enemies as herbivores and pathogens, experimental evidence for this assumption is sparse. We present evidence that natural enemies exert selection on particular plant resistance characters. Specifically, we demonstrate that elimination of natural enemies from an experimental field population of Arabidopsis thaliana alters the pattern of selection on genetic variation in two characters that have been shown to reduce herbivore damage in the field: total glucosinolate concentration and trichome density. The change in pattern of selection reveals that natural enemies imposed selection favoring increased glucosinolate concentration and increased trichome density, and thus, supports one of the major assumptions of the coevolution hypothesis. We also demonstrate that a pattern of stabilizing selection on glucosinolate concentration results from a balance between the costs and benefits associated with increasing levels of this resistance character. This result provides direct confirmation of the appropriateness of cost-benefit models for characterizing the evolution of plant defenses.     

AN EVOLUTIONARY RESOLUTION OF MANIPULATION CONFLICT

Individuals can manipulate the behavior of social partners. However, manipulation may conflict with the fitness interests of the manipulated individuals. Manipulated individuals can then be favored to resist manipulation, possibly reducing or eliminating the manipulated behavior in the long run. I use a mathematical model to show that conflicts where manipulation and resistance coevolve can disappear as a result of the coevolutionary process. I find that while manipulated individuals are selected to resist, they can simultaneously be favored to express the manipulated behavior at higher efficiency (i.e., providing increasing fitness effects to recipients of the manipulated behavior). Efficiency can increase to a point at which selection for resistance disappears. This process yields an efficient social behavior that is induced by social partners, and over which the inducing and induced individuals are no longer in conflict. A necessary factor is costly inefficiency. I develop the model to address the evolution of advanced eusociality via maternal manipulation (AEMM). The model predicts AEMM to be particularly likely in taxa with ancestrally imperfect resistance to maternal manipulation. Costly inefficiency occurs if the cost of delayed dispersal is larger than the benefit of exploiting the maternal patch. I discuss broader implications of the process.     

关于鸡法氏囊淋巴滤泡皮质部形成的研究

初生雏鸡孵出后立即结扎法氏囊管,使外界抗原进入法氏囊腔通路受阻,法氏囊髓质部细胞未见增殖分化,从而没有淋巴细胞穿过基膜形成皮质部。结扎法氏囊管后喂养半个月的雏鸡,再拆除结扎线,恢复泄殖腔与法氏囊的通道,外界抗原又可进入法氏囊腔,刺激滤泡髓部细胞分裂增殖,并穿过基膜形成皮质部。但由于曾结扎半月,所以迁移到皮质部的细胞与对照组比较相对减少。结扎法氏囊管后同时注射枯草杆菌(Bs)和四球菌(Mt),法氏囊滤泡皮质部与正常对照组相似,有的甚至比对照组更为发达。电镜观察皮质部具有不同成熟度的浆细胞。孵出的雏鸡用睾酮(TP)处理后法氏囊滤泡虽有皮质部,但不是正常的皮质部淋巴细胞。实验结果表明滤泡皮质部的形成与孵化后外界抗原的刺激有关,法氏囊作为鸟类特有的体液免疫的中枢淋巴器官,可能仅指胚胎时期发育的淋巴滤泡髓质部,而法氏囊皮质部则可能相当于外周淋巴器官。它的形成必须依赖于外界抗原的刺激。     

THE EXPERIMENTAL FORMATION OF POLYPLOIDY AND ITS EFFECT IN THE GENUS MUSA

Polyploidy was induced in two Musa species and their hybrid by means of immersing newly germinated diploid seedlings in 0.5% aq. colchicine solution. Tetraploid M. balbisiana plants were taller and more robust but had slower growth rate, droopier leaves, fewer suckers, and scantier root systems than the diploids. Tetraploidy affected fruit size and shape in M. balbisiana and in M. acuminata. Tetraploidy did not affect bunch size (the number of fruit-bearing nodes) in M. acuminata banksii but caused great reduction in bunch size of M. acuminata microcarpa ‘Zebrina.’ Doubling of the chromosome number resulted in doubling of the anthocyanin concentration in the leaves of the pigmented banana plants. Colchicine-induced female sterility was detected in a treated diploid plant of M. acuminata subsp. microcarpa. A number of either female or male, or both female and male sterile plants were encountered in colchicine-induced tetraploid M. acuminata species. Only one secondary M. balbisiana tetraploid plant was found to be partially female sterile. Colchicine treatment of the seedlings resulted in chromosomal irregularities at mitosis. Chromosomes appeared as open chains, rings and multiple configurations at metaphase. In the majority of cases doubled chromsomal complements reverted to their original number. However, there were cases in which diploids were induced to tetraploidy and later reverted to triploidy instead of diploidy. Also, there were cases in which triploids were doubled to hexaploidy and later reverted to tetraploidy instead of triploidy. From the close morphological similarity between a number of triploid and tetraploid M. balbisiana plants and some edible triploid cultigens belonging to the “ABB Group,” it is suggested that the karyotype of some of these cultigens could be “BBB” rather than “ABB” which contains one “A” M. acuminata genome. New pathways and additional evolutionary possibilities are incorporated into Simmonds’ scheme on the evolution of edible bananas.     

EVOLUTION AND MANIPULATION OF PARASITOID EGG LOAD

In proovigenic parasitoids such as Leptopilina boulardi, the female emerges with a limited egg load and no further eggs are produced during its adult life. A female thus runs the risk of exhausting this limited supply of eggs before the end of her life. Given that the production of an egg is costly, what is the evolutionarily stable egg load at emergence? This question has attracted a lot of attention in the last decade. Here, we analyze a model that allows us to track both the evolution and the population dynamics of a solitary, proovigenic parasitoid. First, we show how host–parasitoid dynamics feedbacks on the evolution of parasitoid egg load. Second, we use this model to consider the situation in which the parasitoid can be infected by a virus that manipulates the oviposition behavior of the females. In particular, we model the effect of the LbFV virus in L. boulardi, a virus that is known to enhance its horizontal transmission by increasing superparasitism (i.e., the laying of eggs in a host already parasitized). Specifically, we model (1) the effect of the virus on parasitoid egg load strategies , and (2) the evolution of egg load manipulation by the virus. This analysis yields two alternative, yet not mutually exclusive, adaptive explanations for the observation that females infected by the virus harbor higher egg loads than uninfected females. Infected females could either respond plastically to the infection status, or be manipulated by the virus. Further experimental work is required to distinguish between these two hypotheses. In a broader context, we present a general theoretical framework that allows us to study the epidemiology, the evolution, the coevolution, and the evolution of manipulation of various reproductive strategies of parasitoids.     

沙棘油对实验性血栓形成及凝血系统的影响

沙棘油能使实验性血栓形成延迟,具有预防血栓形成的作用。沙棘油有一定的抗凝作用,主要参与内源性凝血系统;且有促纤溶作用,明显降低纤维蛋白原含量,使血浆鱼精蛋白副凝试验呈阳性反应。     

米曲霉两株营养缺陷型原生质体的形成和再生的条件实验*

采用1%溶壁酶加1%玛瑙螺酶(褐云玛瑙螺消化液的冷冻干粉)的混合酶,自米曲霉(Aspergillus oryzae)的两株营养缺陷型中获得了大量的原生质体,并比较了渗透压稳定剂、温度、菌丝体的培养基成分等因素对原生质体形成和再生的作用。无机盐类稳定剂(NaCl、KCl)获得了高产量的原生质体,而有机类(蔗糖、甘露醇、山梨醇)做为稳定剂不甚理想。对120和720菌株的原生质体在高渗再生培养基上进行再生试验,再生率分别为52%和65%。     

米曲霉两株营养缺陷型原生质体的形成和再生的条件实验

采用1%溶壁酶加1%玛瑙螺酶(褐云玛瑙螺消化液的冷冻干粉)的混合酶,自米曲霉(Aspergillus oryzae)的两株营养缺陷型中获得了大量的原生质体,并比较了渗透压稳定剂、温度、菌丝体的培养基成分等因素对原生质体形成和再生的作用。无机盐类稳定剂(NaCl、KCl)获得了高产量的原生质体,而有机类(蔗糖、甘露醇、山梨醇)做为稳定剂不甚理想。对120和720菌株的原生质体在高渗再生培养基上进行再生试验,再生率分别为52%和65%。