Ultrastructural changes in major organelles during spermatial differentiation inBangia (Rhodophyta)

Summary The major organelles within the cells of maleBangia atropurpurea (Roth) C. Ag. filaments undergo a series of ultrastructural transformations during the production of spermatia. Initially, thylakoids within the large axial chloroplast develop a reticulate pattern commencing at the central pyrenoid region. Subsequent changes involve loss of lobes and diminution of volume through division; chloroplasts in final stages contain a few dilated, distorted thylakoids and many plastoglobuli. During differentiation the large nucleolus disappears from the nucleus and four masses of chromatin aggregate near the nuclear envelope. Furrows originating from the nuclear envelope form double membranes around each of the chromatin masses and most of the nucleoplasm is eliminated. Several types of fibrillar vesicles are formed during the process and large floridean starch reserves are utilized. Multilamellar bodies and microbody-like structures occur within the cells during certain phases of spermatiogenesis.     

Différenciation ultrastructurale des jonctions intercellulaires de l'endothélium des capillaires télencéphaliques chez l'embryon de poulet

Résumé Au cours du développement embryonnaire du Poulet, les cellules endothéliales des bourgeons vasculaires et des capillaires néo-formés du télencéphale sont unies par des jonctions transitoires au niveau desquelles les feuillets externes des membranes plasmiques n'ont pas fusionné et sont séparés par un espace intercellulaire mesurable. Des points de fusion de ces feuillets externes apparaissent peu à peu et au hasard dans la zone du contact intercellulaire. Entre ces points persistent des espaces intercellulaires qui assurent encore la communication entre la lumière du capillaire et l'espace extracellulaire du tissu nerveux. L'adjonction de nouveaux points de fusion, entre ceux existant déjà, conduit à la disparition progressive de l'espace intercellulaire et à la formation de véritables zonulae occludentes.

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Ultrastructural differentiation of intercellular junctions in the endothelium of capillaries in the embryonic telencephalon of the chicken

Summary During the embryonic development of the chick, the endothelial cells of the vascular sprouts and of the newly-formed capillaries in the telencephalon are linked by transitory junctions at the level of which the external leaflets of the plasma membrane are not fused and are separated by a measurable intercellular space. Some points of fusion of these external leaflets gradually appear at random in the area of the intercellular contact. Between these points of fusion, some intercellular spaces persist which still allow the communication between the capillary lumen and the extracellular space in the nervous tissue. The adjunction of new points of fusion between the preexisting ones, leads progressively to the disappearance of these intercellular spaces and to the formation of true zonulae occludentes.

L'auteur remercie les Professeurs J. Gayet et G. Grignon de leurs conseils lors de la préparation du manuscrit. Ces recherches ont bénéficié de subventions du Centre National de la Recherche Scientifique (E.R.A. n° 331) et de la Fondation pour la Recherche Médicale Française.     

Les éléments cytoplasmiques au cours de la spermiogenèse du TritonPleurodeles waltlii Michah

Résumé L'origine et la morphogenèse des différents éléments de l'acrosome du spermatozode dePleurodeles waltlii ont été suivies et décrites depuis le tout début de la spermiogenèse. La formation de la vésicule acrosomienne et son évolution en une coiffe acrosomienne se fait selon le schéma classique. Son extrémité apicale se différencie tardivement en un bouton terminal et un crochet. Les trois parties de la coiffe diffèrent dans leur composition et leur structure fine.Les volumineux et complexes éléments situés sous la coiffe acrosomienne: axe, baguette puis manchon périphérique et manchon moyen, sont dépourvus de polysaccharides. Leur origine est envisagées. Ils sont comparés aux éléments situés dans l'espace sous-acrosomien des spermatozodes des autres vertébrés.

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The cytoplasmic elements during spermiogenesis in the triturusPleurodeles waltlii MichahI. Acrosome genesis

Summary The origin and the morphogenesis of the acrosome different parts ofPleurodeles spermatozoon, have been investigated and described from the early beginning spermiogenesis process. The acrosomal vesicle and acrosomal cap formation take place according to the classical scheme. The acrosomal anterior tip cap late differentiate in a blunt terminal knob and a hook. The three cap parts differ in their composition and fine structure.The large and complicated structure stretching under the acrosomal cap: axis, peripheral muff and middle muff, are devoided of polysaccharides; their origin is discussed. They are compared with the subacrosomal components lying in the other vertebrates spermatozoon subacrosomal space.

Equipe de Recherche Associée au C.N.R.S., E.R.A. n^o 129.     

包囊游仆虫包囊形成和解脱过程中纤毛器的分化

包囊游仆虫(Euplotes encysticus)形成包囊时,各类纤毛器中的纤毛杆被部分地或全部地吸收,毛基体被保留下来。休眠包囊中,背纤毛器的定位无明显变化,但原腹面纤毛器中的口围带和波动膜、额腹棘毛和横棘毛,以及左、右尾棘毛都按序陷入在细胞质内深处,并相互汇聚在一起。脱包囊时,纤毛结构在原毛基体上再分化,新纤毛器按口围带、横棘毛、额腹棘毛和左、右尾棘毛的顺序从细胞内显露出来。     

Identification of Two Distinct Isoforms of the Guanine Nucleotide Binding Protein Go in Neuroblastoma × Glioma Hybrid Cells: Independent Regulation During Cyclic AMP-Induced Differentiation

Three distinct antipeptide antisera generated against synthetic peptides that represent parts of the primary sequence of the alpha-subunit of the (pertussis toxin-sensitive) guanine nucleotide binding protein G0 were used in two-dimensional immunoblots of membranes of neuroblastoma X glioma (NG108-15) cells. Each antiserum identified two distinct polypeptides of some 39 kDa. These had apparent isoelectric points of 5.5 and 5.8. Differentiation of NG108-15 cells in response separately to dibutyryl cyclic AMP (cAMP), 8-bromo cAMP, forskolin, and prostaglandin E1 produced elevated levels of G0 alpha, as has previously been noted in one-dimensional immunoblots. Two-dimensional analysis demonstrated that the cAMP-induced increases in levels of G0 alpha were only of the more acidic isoform. The two isoforms were both substrates for pertussis toxin-catalysed ADP-ribosylation and did not appear to represent differentially phosphorylated forms of the same polypeptide. Separation of the two forms of G0 alpha could be achieved in one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis when 4 M deionized urea was included in the resolving gel. The more slowly migrating band was the acidic form and corresponded exactly in mobility with the major form of G0 from both rat and mouse brain. There was no equivalent in brain of the more rapidly migrating form of G0 from the cells. In agreement with the data from two-dimensional gels, only the more slowly migrating form was expressed in considerably higher amounts following cAMP-induced differentiation of NG108-15 cells. Of these two forms of "G0," the acidic species is equivalent to G0 from brain, but the basic form is not identical with G0*, which has been purified from bovine brain.     

多聚酶链反应技术鉴别肾综合征出血热病毒血清型的初步研究

肾综合征出血热(HFRS)为一组抗原性密切相关的布尼亚科汉坦病毒引起的急性传染病。在我国存在至少两种临床表现、动物宿主及流行特征截然不同的血清型别,即血清Ⅰ型(汉坦型)和血清Ⅱ型(汉城型)。这两型病毒间的血清学定型已有报道。近年来,除啮齿类动物外,从临床病人以及非啮齿类动物体内也分离到了HFRS病毒。同时出现两类型别毒株共存,以及从家鼠体内分离到野鼠型毒株或从野鼠体内分离到家鼠型毒株的复杂情形。为此,准确检定并鉴别不同来源毒株型别,将为深入了解其病原学、流行病学以及制定疫苗生产策略提供重要信息。     

Development of a series of monoclonal antibodies recognizing leukocyte differentiation antigens of Japanese monkeys (Macaca fuscata)

Six monoclonal antibodies to Japanese monkey leukocytes were developed. These monoclonal antibodies, designated the U series, cover most kinds of leukocytes (pan T cells, CD8+ cells, CD8+ subset and granulocytes, CD16+ cells, monocytes/macrophages), and should be useful in the immunological analysis of primate models, such as tissue transplants and virus-related diseases, in particular, acquired immune deficiency syndrome (AIDS).     

The effect of low- and high-density lipoprotein cholesterol on steroid hormone production and ACTH-induced differentiation of rat adrenocortical cells in primary culture

Summary The choroid plexus consists of the choroidal epithelium, a derivative of the neural tube, and the choroidal stroma, which originates from the embryonic head mesenchyme. This study deals with epithelio-mesenchymal interactions of these two components leading to the formation of the organ. Grafting experiments of the prospective components have been performed using the quail-chicken marker technique. Prospective choroidal epithelium of quail embryos, forced to interact with mesenchyme of the body wall of chicken embryos, gives rise to a choroid plexus showing normal morphogenesis and differentiation. The choroidal epithelium induces the differentiation of organtypical fenestrated capillaries, which are highly permeable to intravenously injected horseradish peroxidase. The choroidal epithelium of the grafts constitutes a blood-cerebrospinal fluid barrier. On top of the choroidal epithelium, there are epiplexus cells displaying a typical ultrastructure. The experimental results show that these cells do not originate from the transplanted neural epithelium. Prospective choroidal stroma of chicken embryos does not exert a choroid plexus-inducing influence upon a quail embryo's neural epithelium isolated from parts of the brain that normally do not develop a choroid plexus. The experiments show that the choroidal epithelial cells are determined at least three days before the first organ anlage is detectable.This work was supported by the Deutsche Forschungsgemeinschaft (grant Ch 44/7-1)     

Cultured fetal rat pituitaries kept in synthetic medium are able to initiate synthesis of trophic hormones

Summary An immunohistochemical study was performed to determine the capacity of early fetal pituitaries to differentiate into specific hormone-synthesizing tissue in the absence of any influence from the central nervous system. Rathke's pouches from rats were removed from their juxtadiencephalic position on day 11 and 12 of gestation and maintained for 2–7 days in a chemically defined culture medium (M 199) without antibiotics and serum supplementation. The immunocytochemical observations provided evidence for the differentiation of ACTH-, TSH-gb-, LH-gb-, FSH-gb-, GH- and PRL-synthesizing cells in the isolated organ cultured from 11 to 12-day-old pituitary primordia. The appearance of specific hormone-synthesizing cells in vitro displayed a delay of 1.5–2 days compared to the day of appearance in vivo, however, the sequential order of developmental events occurred as observed in vivo. The present results suggest that endocrine or neuroendocrine signals are not required for the expression of specific secretory functions of fetal pituitaries, at least at an age of 11–12 days.     

Doxorubicin affects tau protein metabolism in human neuroblastoma cells

The microtubule associated protein called tau, found primarily in neurons, was detected in a human neuroblastoma cell line, LAN-5. Cells treated with retinoic acid (2.0×10^–5M) differentiate and acquire processes similar to neurons. Differentiated and logarithmically growing undifferentiated cells were exposed to varying doses of doxorubicin (an anthracycline chemotherapeutic antibiotic). While doxorubicin was lethal to many undifferentiated dividing cells, it was not as damaging to differentiated cells. After 2 to 4 days of doxorubicin treatment, the cells were harvested, the protein concentration determined and SDS-PAGE performed. Proteins were blotted onto nitrocellulose paper and immunostained with either a rabbit antiserum or mouse monoclonal antibody to tau. Undifferentiated LAN-5 cells treated with 4.0×10^–8M doxorubicin for 4 days and cells treated with 8.0×10^–8M doxorubicin for 2 days displayed a distinct lower band (just below the 50kd marker) that was either absent or very faint in untreated controls.Special issue dedicated to Dr. Paola S. Timiras.