高等植物叶绿体和线粒体免疫亲近性的研究

以火箭免疫电泳分析表明:大豆叶绿体抗体与大豆线粒体有免疫交叉反应,同时大豆线粒体抗体与大豆叶绿体也有免疫交叉反应,但是大豆线粒体的抗体与鼠肝线粒体之间无免疫交叉反应。这说明高等植物线粒体对叶绿体比之对动物线粒体在免疫特性上有更大的亲近性,亦即高等植物线粒体和高等植物的叶绿体有更大的同源性。经火箭免疫电泳、交叉免疫电泳和线状免疫电泳进一步分析表明:菠菜偶联因子抗体(AbCF_1)和大豆线粒体、大豆叶绿体间,大豆线粒体抗体与CF_1和大豆叶绿体之间,以及大豆叶绿体的抗体(AbC)与CF_1和大豆线粒体间有免疫交叉反应,说明两种换能器之间有免疫亲近性,并分别与CF_1存在免疫亲近性。这揭示两种换能器免疫亲近性的表现是由于存在共同物质基础所致,这内在共同物质基础是偶联因子。这个结果有力地支持高等植物叶绿体和线粒体在结构和功能上以及发生上存在同源性的观点,在理论上也为两种换能器的起源和演化上存在同源性提供了一些依据。     

DEVELOPMENT AND CYTOCHEMISTRY OF THE THYLAKOIDAL BODY IN TOBACCO CHLOROPLASTS

Developing plastids in young tobacco leaves contain thylakoidal bodies, inclusions bound by a single membrane continuous with stroma lamellae. Both the thylakoidal body and its attached lamellae contain an enzyme that catalyzes an oxidation reaction with 3,3'-diaminobenzidine (DAB). DAB staining of the thylakoidal body and lamellae is not the result of photo-oxidation and is inhibited by potassium cyanide. The thylakoidal body disappears as plastids develop into chloroplasts and, further, the lamellar systems of the mature chloroplasts do not stain with DAB. In developing chloroplasts, it is suggested that the thylakoidal body forms by accumulation of protein which stains with DAB within primary lamellae derived from the inner plastid membrane. The ultrastructural and cytochemical evidence suggests that the thylakoidal body stores protein used later in lamellar formation.     

LABILE SEX EXPRESSION IN ANDROMONOECIOUS SOLANUM HIRTUM: FLORAL DEVELOPMENT AND SEX DETERMINATION

Sex expression (the proportions of hermaphrodite and staminate flowers produced) of the andromonoecious species Solatium hirtum is labile, and this lability of whole plant sex expression is due to labile sex expression of individual floral buds. In this paper I examine the developmental processes that underlie the differences in floral sex expression of hermaphrodite and staminate flowers of Solarium hirtum, focusing particularly on the processes responsible for the observed lability of floral sex expression. Differences in bud growth rate and relative growth of floral organs in these buds are evident at about the time of megasporocyte meiosis (11–12 days before anthesis). However, gynoecial sterility in staminate buds does not occur until just 6–7 days before anthesis. At this time, abnormalities in ovule development occur in staminate buds: the ovules begin to appear necrotic, the integumentary tapetum collapses, and the megagametophytes of many ovules cease normal development. These observations are consistent with the predictions of labile floral development.     

SUBMICROSCOPIC STRUCTURE AND DEVELOPMENT OF THE CHLOROPLASTS OF PSILOTUM TRIQUETRUM

Sun , C. N. (Washington U., St. Louis, Mo.) Submicroscopic structure and development of the chloroplasts of Psilotum triquetrum. Amer. Jour. Bot. 48(4): 311–315. Illus. 1961.—Aerial stems and stem tips of Psilotum triquetrum were used for the study of the fine structure and development of chloroplasts. The chloroplasts of Psilotum are ellipsoidal, with a principal axis of approximately 13 μ and a short axis of approximately 3.6 μ. They are bounded by a well-defined outer membrane which consists of 2 layers. Within the laminar system of the stroma, the lamellated grana appear as sharply defined regions. The grana are about 1–1.6 μ in diameter. They are distributed more or less uniformly throughout the entire chloroplast with the exception of a very narrow peripheral zone. Relatively large, osmiophilic globules occur in groups in the stroma. The development of the Psilotum chloroplast may be summarized as follows: (1) in the undifferentiated proplastid, vesicles occur; (2) lamellated layers are formed by the fusion of vesicles; (3) the lamellae multiply by a process of thickening and splitting; (4) the grana are differentiated within a certain area by heterogeneous deposition of material and by further cleavage of the lamellae. Osmiophilic globules are present throughout the developmental stages, and increase in number and size with increase in age of the chloroplast.     

SIZE AND SEX IN CYPRAEIDAE

Samples of Cypraea (Notocypraea) angustata Gmelin 1791 and ofCypraea errones L. 1758 have been measured, and the sex of theindividuals determined. The males of C. angustatawere foundto be significantly shorter than the females. Differences betweenother dimensions in this species, and between all dimensionsmeasured in C. errones, were of little significance It has recently been shown (Griffiths, 1961) that the malesof Umbilia hesitata Iredale were greater in length than thefemales. Other evidence in this paper, and some subsequent measurementsmade by Schilder and Schilder (1961) have suggested that theconverse might be true for some other species of CYPRAEIDAE Sample groups of shells of C. errones and C.(N) angustata havenow been measured. The shells were then cut open, and thesexof the animal determined by the presence or absence of a penis.The results are givenin Tables I and II (Received 10 March 1961;     

除草剂苄嘧磺隆对粗梗水蕨配子体生长和性器官分化的影响

 稻田施用的除草剂可能会污染邻近水域,对非靶标水生植物产生影响。国家二级重点保护野生植物粗梗水蕨(Ceratopteris pteridoides)主要分布于稻田及其周围水域,其有性繁殖敏感阶段与除草剂施用时间一致,配子体易暴露在除草剂污染中。为了评价除草剂污染对水生态环境特别是对非靶标国家重点保护野生水生植物的影响,保护生物多样性和水生生态环境,该文研究了除草剂苄嘧磺隆(Bensulfuron-methyl)对粗梗水蕨配子体生长和性器官分化的影响。结果表明,苄嘧磺隆对粗梗水蕨孢子萌发没有影响,但对其配子体生长有抑制作用。苄嘧磺隆浓度和粗梗水蕨配子体面积呈明显的剂量效应关系,苄嘧磺隆对粗梗水蕨配子体生长抑制的EC₅₀(半数效应浓度)为0.086μg&;#8226;L^-1,低于已报道的环境背景浓度。随着苄嘧磺隆浓度升高,粗梗水蕨的雌雄同体配子体逐渐减少,且配子体上颈卵器形成时间推迟。在苄嘧磺隆为10μg&;#8226;L^-1时,粗梗水蕨没有雌雄同体配子体形成。以上研究结果表明,低浓度苄嘧磺隆可抑制粗梗水蕨配子体的生长并影响其性器官的分化,使粗梗水蕨有性繁殖能力减弱。     

MEIOSIS,BLADE DEVELOPMENT,AND SEX DETERMINATION IN PORPHYRA PURPUREA (RHODOPHYTA)1

The discovery in the early 1980s that meiosis occurs during germination of conchospores of Porphyra yezoensis Ueda suggested that the sexually divided fronds of Porphyra purpurea (Roth) C. Agardh might similarly originate from meiotic segregation of a pair of sex-determining alleles during early sporeling development. After establishing conditions suitable for propagating P. purpurea in culture, observations on developing sporelings demonstrated that meiosis takes place during the first two divisions of the germinating conchospores. In the first division, the spore is split into an upper and lower cell. In the second, an anticlinal division in the upper cell yields two daughter cells situated one beside the other, and a periclinal division in the bottom cell gives two cells arranged one above the other. Thus, during normal development, the first four cells of the sporeling constitute a meiotic tetrad whose cells are arranged in a characteristic fashion. Stable color mutants of P. purpurea were isolated, genetically characterized, and used as genetic markers to follow the fate of individual cells of the tetrad during subsequent frond development. Nearly the entire blade of the mature thallus is derived from the two upper cells of the tetrad, with the two lower cells mostly giving rise to the rhizoidal holdfast region. Cell lineage boundaries laid down by the segregation of color alleles at meiosis corresponded perfectly with those later defined by sexual differentiation on the same fronds, strongly supporting the hypothesis that sex determination in P. purpurea is controlled by alleles at a segregating chromosomal locus.     

DIRECT COUNTING AND SIZING OF MITOCHONDRIA IN SOLUTION

Resistive particle counting has been developed for the accurate sizing and counting of mitochondria in solution. The normal detection limit with a 30 µ aperture is 0.48 µ diameter, or 0.056 µ³ particle volume The mean volume of rat liver mitochondria was 0.42 µ³ or 0.93 µ in diameter. The average value for numbers of particles per milligram of mitochondrial protein was 4.3 x 10³, and per gram of rat liver was about 11 x 10¹⁰. These values compare satisfactorily with those derived by light microscopy and electron microscopy. The mean volume for mitochondria from rat heart was 0 60 µ³ and from rat kidney cortex, 0.23 µ³. These values agree within 15% of those determined by electron microscopy of whole tissue. Mitochondrial fragility and contaminating subcellular organelles were shown to have little influence on the experimentally determined size distributions The technique may be applied to rapid swelling studies, as well as to estimations of the number and size of mitochondria from animals under different conditions such as liver regeneration and hormonal, pathological, or drug-induced states Mitochondrial DNA, RNA, cytochrome c-oxidase, cytochrome (a ÷ a₃), and iron were nearly constant per particle over large differences in particle size. Such data may be particularly valuable for biogenesis studies and support the hypothesis that the net amount per particle of certain mitochondrial constituents remains constant during mitochondrial growth and enlargement     

SPHEROSOMES AND MITOCHONDRIA IN THE LIVING FUNGAL CELL

Study of living hyphae of Fusarium oxysporum Schlect., Fomes annosus (Fries) Cooke, Ceratocystis fagacearum (Bretz) Hunt, Basidiobolus ranarum Eidam, and Mycotypha microspora Fenner with phase contrast revealed that these fungi have spherosomes similar to those in vascular plants. The spherosomes are conspicuous in the hyphal tip, suggesting some function other than fat synthesis. It may be that the Woronin bodies reported by other workers are spherosomes. Mitochondria in these fungi are highly pleomorphic and exhibit saltatory movement. They often interact with nuclei in a manner suggesting close membrane contact.