Étude de la cytodifférenciation du rein de l'Epinoche femelle après traitement par la méthyltestostérone

Résumé Au microscope électronique, l'action de la méthyltestostérone sur les cellules rénales de l'Epinoche femelle se traduit par une cytodifférenciation conduisant à la formation de cellules glandulaires muqueuses. Elle a lieu simultanément à deux niveaux distincts:Au niveau du tubule proximal, le premier signe visible de cytodifférenciation est une activation du nucléole, accompagnée par une augmentation de taille des cellules. Puis on assiste à un développement de l'ergastoplasme et de l'appareil de Golgi et à l'élaboration de deux types de sécrétions: d'abord des granules de 2000–2500 Å, ensuite des grains de mucigène typiques, qui subissent rapidement une transformation muqueuse.Une cytodifférenciation régressive intervient en même temps. Elle concerne la pinocytose apicale qui disparaît.Au niveau des tubules collecteurs, la cytodifférenciation se traduit par la formation d'un mucus hyalin d'origine golgienne. Elle s'accompagne également d'une disparition de la pinocytose.La méthyltestostérone est capable de provoquer, chez la femelle, une cytodifférenciation rénale identique à celle que l'on observe chez le mâle pendant la période de reproduction. La transformation muqueuse des cellules rénales est donc sous le contrôle de la seule testostérone, qui déclenche au niveau cellulaire un ensemble de processus conduisant à la formation de mucus.Au microscope électronique, on constate que l'élaboration de mucus prêt à l'excrétion est achevée au bout de trois jours dans les tubules proximaux alors que dans les tubules collecteurs elle ne demande que 24 heures.

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Action of methyl testosterone on the cytodifferentiation of the kidney of the female three-spined Stickleback

Summary At the microscopic level, the action of methyl testosterone on the cells of the kidney of the female three-spined Stickleback gives raise to a cytodifferentiation which leads to the formation of mucous glandular cells. This action is evident at two different levels:At the level of the proximal tubule, the first visible sign of cytodifferentiation is an activation of the nucleolus, accompanied by a growth of the cell size. Then a rapid development of the ergastoplasm and the Golgi apparatus takes place, which leads to the elaboration of two types of secretory particles: granules of 2000–2500 Å in diameter appear first, then typical mucigen granules become visible. These latter undergo a rapid mucous transformation.A regressive cytodifferentiation occurs at the same time. It concerns the apical pinocytosis which disappears in the cells undergoing the glandular differentiation.At the level of the collecting tubules, the cytodifferentiation is characterized by the elaboration of a clear mucus which originates in the Golgi apparatus and migrates to the apex of the cells. A disappearance of the pinocytosis is also noticeable.In the kidney of the female, methyl testosterone induces a cytodifferentiation which is identical to that occuring in the male during the breeding period. So the mucous transformation of renal cells is under the control of a single hormone: the testosterone, which is able to give raise to a succession of phenomena leading to the formation of a mucous secretion.With the electron microscope, it is possible to demonstrate that three days are necessary for the elaboration of the mucus ready to be discharged in the lumen of the renal proximal tubules. In the collecting tubules, the reaction occurs more quickly, after only two days of treatment.

L'auteur tient à remercier Monsieur le Professeur E. Follénius pour ses conseils et son aide précieuse au cours de la réalisation de ce travail.     

Plasticity of the endoplasmic reticulum in three cell types of slugs poisoned by molluscicides

Summary In three cell types of slug tissue-the crypt, mucous and storage cell-ultrastructural alterations of the endoplasmic reticulum (ER) can be induced by oral application of the pesticides Cloethocarb, metaldehyde, or Dimilin. In the crypt cells of the hepatopancreas, the narrow-luminar cisternae of the rough endoplasmic reticulum which are parallelly arranged in controls get slightly dilated, vesiculated and form circular arrays. Intermediate stages between narrow luminar, vesiculated and circularly arranged ER can be observed. In the mucous cells of the skin and the stomach, the wideluminar cisternae of the rough endoplasmic reticulum the lumen of which contains tubular-like structures become heavily dilated. Also in this cell type, intermediate stages between dilated cisternae without tubular-like structures and non-dilated cisternae can be observed. In the storage cells of the crop, in which lipid storage is reduced after molluscicide application, the formation of a special type of ER characterized by locally enlarged ER-cisternae, broken through by several cytoplasmic strings, becomes obvious.     

Ca2+-ATPase in mucous and oxyntico-peptic cells of the fowl proventriculus

Summary Calcium adenosine triphosphatase (Ca²⁺-ATPase) was localized by means of histo- and ultracytochemistry in the secretory cells of the proventriculus of the domestic fowl. The mucous cells exhibited plasmalemmal-associated enzyme activity on the external aspect of the basolateral cell membrane. Intracellularly, the luminal aspect of Golgi-membranes and of secretory vesicle membranes reacted positively for Ca²⁺-ATPase activity, as did the apical cytosol and the matrix of lysosomes. Oxyntico-peptic cells were characterized by apical and apico-lateral plasmalemmal activity and by an organelle-associated distributional pattern similar to that in the mucous cells. In addition, Ca²⁺-ATPase was associated either with the matrix of mitochondria or with tubuli of the rough-surfaced endoplasmic reticulum. The results are discussed with respect to messenger and effector functions of calcium in the process of proventricular mucus secretion. In addition, Ca²⁺-ATPase distributional patterns in the oxyntico-peptic cell are related to the unique structure and function of these cells.     

Changes in expression of two endogenous β-galactoside-binding isolectins in the dermis of chick embryonic skin during development in ovo and in vitro

In order to elucidate the roles of metal-independent animal lectins, we systematically investigated changes in expression of 2 kinds of -galactoside-binding isolectins (MW 14 and 16 kDa) in the dermis of chick embryonic tarsometatarsal skin during the course of development. These lectins were immunohistochemically located at different stages of development both in ovo and in vitro by light and electron microscopy. Light-microscopic observation showed that while positive staining for the 14-kDa lectin was weak at days 8 and 10 it became intense after day 13. In contrast, staining for the 16-kDa lectin was intense at days 8, 10, and 13, but it became weak after day 17 when keratinization of the epidermis was completed. Immuno-electron-microscopic observation revealed that both the 14 and 16-kDa lectins were located on the basement membrane, in the extracellular matrix, and in both the cytoplasm and the nucleus of dermal fibroblasts. Distribution of the 2 isolectins was also examined in cultured skin explants in vitro. The results were almost the same as those obtained in ovo when the skin explant was keratinized in the presence of hydrocortisone. However, in the skin explant where keratinization was prevented and mucous metaplasia was induced by the addition of vitamin A, the distribution of the 14-kDa lectin in the epidermis was significantly affected. These results indicate that (1) the expression of the 2 isolectins is differently regulated in both the dermis and epidermis, (2) the 16-kDa lectin is involved in the early stage of the formation of the dermis and the basement membrane and is replaced by the 14-kDa lectin as keratinization of the epidermis occurs, and (3) the expression of the 2 isolectins in the dermis is not significantly affected by the induction of mucous metaplasia, in contrast to their drastic changes in the epidermis.     

圆尾鲎消化道组织结构与黏液细胞分布

利用石蜡切片、苏木素-伊红(H.E)和阿利新兰-高碘酸雪夫试剂(AB-PAS,AB,pH 2.5)组化染色技术研究圆尾鲎(Carcinoscorpius rotundicauda)消化道组织结构及其黏液细胞的分布特征。圆尾鲎消化道外形为一直管状,中肠部位有分支。H.E染色结果显示,食道、胃、幽门、中肠与后肠的管壁一般结构由外至内分为外膜、肌肉层、黏膜下层、黏膜层。食道是一段短管状结构,肌肉层较胃壁的薄但几丁质层极厚。胃则为一膨大的砂囊结构,内含一定数量的纵行黏膜皱褶,肌肉纤维排列整齐,几丁质层较薄。幽门与中肠套叠,幽门壁肌肉层很薄,几丁质层清晰可见。中肠和后肠结构差异不大,具有一定数量的黏膜皱褶,上皮细胞间分布比较多的黏液细胞,均无几丁质层。AB-PAS组化染色结果显示,消化道有Ⅰ和Ⅱ型两种黏液细胞,不同部位分布数量差别很大。食道和幽门未见黏液细胞。胃黏膜下层有少量Ⅱ型黏液细胞。中肠和后肠黏液细胞数量比较多,尤其是与幽门套叠的中肠前端区域,均以Ⅱ型黏液细胞为主,主要分布在黏膜下层和黏膜上皮。在后肠黏膜下层有Ⅰ型黏液细胞分布,而黏膜上皮则分布密集的Ⅱ型黏液细胞。圆尾鲎消化道组织结构及黏液细胞分布特征反映其不同部位功能的差别,体现食性与消化机能相协调的特点。     

感染肺炎链球菌猕猴消化系统白细胞介素6 的表达观察

检测猕猴自发性感染肺炎链球菌后,白细胞介素6 在胃肠道以及肝脏、食管的表达变化,探讨肺炎链球菌的发病机制以及自发性肺炎链球菌性肺炎的病理特点。采用常规H. E.染色观察消化系统病理组织学变化,采用免疫组织化学和原位杂交方法检测白细胞介素6 在肝脏、食管、空肠、盲肠和胃组织的表达变化。各组织表现出典型的炎症病变,肝组织和肠腺均可见大面积坏死,在空肠、盲肠和肝脏中有明显的广泛性出血和充血现象;肠道有大量炎性细胞浸润。和健康组比较,白细胞介素6 在感染组的胃肠道以及肝脏、食管中的表达均呈现升高趋势,感染组的IL-6 阳性细胞总面积比正常组有显著性升高
(P < 0.05)。在胃肠道以及食管的表达主要集中在粘膜层,在肝脏相对集中分布于血管周围。阳性细胞包括了部分腺体细胞、肝细胞、内皮细胞、未角化
上皮细胞以及淋巴细胞。白细胞介素6 作为一种炎症细胞因子在肺炎链球菌感染中发挥了一定的作用,可能参与了肺炎的病理过程并对机体清除肺炎链球菌有一定促进作用。     

团头鲂黏蛋白基因Muc5b克隆及表达分析

摘要：黏液（mucus）在鱼体防御外界病原侵袭、信息传递、调节渗透压等方面具有重要作用。黏蛋白（mucin）作为黏液的基础骨架组分,与其相关的研究正受到广泛的关注。在本研究中,作者克隆获得团头鲂（Megalobrama amblycephala）Muc5b mRNA 的部分序列3895 bp,并通过qRT-PCR分析了Muc5b在团头鲂不同组织的表达分布及其在捕捞应激后在鳃和表皮中的表达变化。序列分析结果显示,团头鲂Muc5b与鲤等脊椎动物的Muc5b有较高的同源性,其N端含有黏液蛋白特异性结构域：三个VWD区域,三个C8区域,二个TIL区。组织表达分析结果表明,Muc5b在鳃和表皮表达量相对较高,在脑、脾、肾中表达水平较低,在肝、肠道几乎不表达。捕捞应激后1 h时鳃中Muc5b显著降低（P < 0.05）,24 h时恢复初始水平;表皮中4 h时Muc5b显著上升（P < 0.05）,24 h时恢复到初始水平。     

Surface architecture of the oropharyngeal cavity and the digestive tract of Mulloidichthys flavolineatus from the red sea,Egypt: A scanning electron microscope study

Surface architecture of the buccal cavity and the surface organization of the luminal mucosa of the oesophagus, stomach, and intestine of the carnivorous fish M. flavolineatus from the Red Sea were studied by using SEM. The results revealed that M. flavolineatus has four kinds of teeth; curved-blunt, wedge-shaped, flattened crowns, molariform and papilliform. Three types of taste buds (type I, II and III) were recorded in the oropharyngeal cavity. It was observed that taste buds and teeth are co-located in the pharyngeal region. Characteristic patterns of microridges of the surface cells in the oral cavity and oesophagus were observed. Mucous cells are distributed in the lining of the mouth cavity, oesophagus, stomach, and intestine. Characteristic patterns of mucosal folds throughout the alimentary canal, concerning oesophagus, stomach, and intestine were revealed. Numerous gastric pits, which represents the emergence of the gastric glands, were recorded in the anterior and middle regions of the stomach. Complex patterns of the folds and mucous cells were recorded in the intestinal mucosa. These results were discussed with other teleost fishes.     

鲇肠道黏液细胞的类型、分布、发育及分泌方式研究

利用阿利新蓝-过碘酸雪夫氏试剂(AB-PAS,AB染液pH2．6),对鲇(Silurus asotus)肠道黏液细胞的类型与分布进行了研究,同时采用扫描和透射电镜,研究了黏液细胞的发育与分泌方式。结果显示:鲇肠道黏液细胞染色后呈深蓝色、淡蓝色和浅蓝色,主要含有酸性黏多糖:形态上进一步可将其分为囊状、梨状和杯状三种形态。肠道中黏液细胞的分布密度以中肠最高。其次是后肠,前肠最低;肠道黏液细胞由肠黏膜基底层细胞衍生后,不断向肠腔表层推移而发育成熟;发育过程中黏液细胞内富含大小不等的黏原颗粒,其分泌方式为顶浆分泌。