二个不同发育阶段茶银尺蠖雌蛾性腺超微结构的比较研究

本文利用扫描电镜和透射电镜分别对不同发育阶段的茶银尺蠖Scopula subpunctaria Herrich-Schaeffer雌蛾性信息素腺体进行了观察和研究,对探索信息素的合成途径提供科学依据。结果表明,雌蛾性信息素腺体位于第8、9/10腹节的节间膜上,由其表皮下方的单层上皮细胞组成,并几乎覆盖整个节间膜形成一个近乎完整的环状。成熟雌蛾(3日龄)性腺的超微结构照片显示性腺细胞具有发达的微绒毛、质膜内褶、大量的脂滴、细胞间的运输孔道以及细胞桥粒等结构组织。而在未成熟雌蛾(羽化5h内)性腺细胞内,这些结构均明显缺失或发育不完整。     

Ultrastructural changes of sebaceous glands in castrated and testosterone-treated male rats

Summary The effect of testosterone on the sebaceous gland was studied in the male rat. Biopsies of dorsal skin from intact rats, from rats four weeks after castration, and from castrated rats treated with testosterone propionate for three weeks at a dose of 250 g/kg/day (s.c.) were examined by electron microscopy. In the treated animals intermediate sacrifices were performed on days 4,7,14,21. Stereology was used for a morphometric analysis of the smooth endoplasmic reticulum (SER). The presence of a vesicular endoplasmic reticulum throughout the cytoplasm of differentiating cells was observed in the sebaceous glands of intact rats. Following castration there was a shrinkage of these cells and a striking decrease in the volume density of the endoplasmic reticulum vesicles. The administration of testosterone to gonadectomized rats resulted in an increase in vesicle content above the normal level from the first week as revealed by stereological analysis. This study confirms the trophic effect of the androgen on the sebaceous gland at a subcellular level. Furthermore, it is shown that stereology is a useful method for detecting early hormone-induced changes and could be valuable for studying the effects of anti-androgens on this gland.     

Ultrastructural changes in the uropygial gland of the male Japanese quail,Coturnix coturnix,after testosterone treatment

Summary The ultrastructure of the uropygial gland of the male quail was compared to that of the sebaceous gland of the male rat after castration and testosterone treatment of both species. In intact animals, the differentiating cells of these glands displayed almost the same pattern as regards their smooth endoplasmic reticulum, an organelle involved in lipogenesis in both cases. Castration reduced the volume of this organelle, while testosterone administration restored cell morphology to a normal or supranormal level. Finally, this study showed that at ultrastructural level, there is a close functional analogy between the uropygial gland of quail and the sebaceous glands of rats as regards their androgen dependency. Consequently, the uropygial gland might be an attractive model for study of action of androgens on sebaceous-like glands.     

p53 induces skin aging by depleting Blimp1+ sebaceous gland cells

p53 is an important inducer of organismal aging. However, its roles in the aging of skin remain unclear. Here we show that mice with chronic activation of p53 develop an aging phenotype in the skin associated with a reduction of subcutaneous fat and loss of sebaceous gland (SG). The reduction in the fat layer may result from the decrease of mammalian TOR complex 1 (mTORC1) activity accompanied by elevated expression of energy expenditure genes, and possibly as compensatory effects, leading to the elevation of peroxisome proliferator-activated receptor (PPAR)γ, an inducer of sebocyte differentiation. In addition, Blimp1⁺ sebocytes become depleted concomitantly with an increase in cellular senescence, which can be reversed by PPARγ antagonist (BADGE) treatment. Therefore, our results indicate that p53-mediated aging of the skin involves not only thinning through the loss of subdermal fat, but also xerosis or drying of the skin through declining sebaceous gland activity.     

The ultrastructure of the human fetal pineal gland

Summary The ultrastructure of the pineal gland of 18 human fetuses (crown-rump lengths 30–178 mm) was investigated.The pineal gland exhibits a pyramidal shape and consists of an anterior and posterior lobe. Only one parenchymal cell type, the pinealocyte, was observed. Few neuroblasts were seen between the pinealocytes and in the extended perivascular space. The pinealocytes possess all the organelles necessary for hormone synthesis. No specific secretory granule could be observed. The organ is abundantly vascularized and richly innervated. The morphology of the capillaries indicates the existence of a blood-brain barrier.The ultrastructure of the human fetal pineal gland suggests that the gland has a secretory function in early intrauterine life. Acknowledgements. The author is grateful to Mrs. Yael Balslev and Miss Inger Ægidius for their able technical assistance. This investigation was supported in part by The Carl and Ellen Hertz's foundation and the Johann and Hanne Weimann foundation.     

Comparative ultrastructure of microhairs in grasses

Ultrastructure of microhairs is described for 17 species of Poaceae, involving four subfamilies and the 'chloridoid', 'panicoid' and 'Enneapogon' morphological types. The plasma membrane invaginations known as partitioning membranes implicated in salt secretion were found in the basal cells of only some of the 'chloridoid type' microhairs. They were absent from 'panicoid type' microhairs, but present in the cap cells of the 'Enneapogon type'. Characteristics common to known secretory tissues, however, were observed in all microhairs studied, implying secretory activity in all the morphological types.     

Fine structure of the postpygidial gland in Aenictus army ants

Billen, J., Gobin, B. & Ito, F. 1999. Fine structure of the postpygidial gland in Aenictus army ants. – Acta Zoologica (Stockholm) 80: 307–310
Army ants of the genus Aenictus are characterized by the presence of a conspicuous postpygidial gland, which is the source of the trail pheromone. The paired gland at each side consists of a reservoir sac into which the secretory cells open through their accompanying duct cells. The secretory cells are characterized by a well developed Golgi apparatus, numerous mitochondria and strands of smooth endoplasmic reticulum. The reservoir opens near the abdomen tip, which facilitates deposition of the secretory products onto the substrate. The large reservoir of the postpygidial gland may enable the incessant trail laying of at least one of the investigated species.     

Ultrastructure and nature of secretory proteins in the male accessory gland of Drosophila funebris

The ultrastructural differentiation of the secretory cells and the nature of secretory proteins in the male accessory gland of Drosophila funebris have been studied by electron-microscopic and immunological methods. (1) In the pupae at $\text{1}\text{1}\text{2}$ days before eclosion, secretory products can be detected in the lumen, even though most glandular cells are at the initial phase of differentiation. At the time of eclosion both main and secondary cells are fully differentiated, but the whole set of five immunologically active proteins are detectable only on the second to third day of adult life. (2) The secondary cells contain giant protein granules, the so-called filamentous bodies, which become partially fused and the filaments assume a twisted form. Randomly dispersed filaments and closely packed filament bundles are also visible in the gland lumen. Antigenic labelling of ultrathin sections and immunoreplica electrophoresis yielded no evidence for the microtubular nature of these filaments. The secretion stored in the lumen contains in addition a large quantity of flocculent proteins which have their origin in the main cells. (3) During the period of high secretory activity in the 7-day-old male flies no vacuolization and disintegration of either the main or secondary cells have been observed. We conclude that both types of cells have the merocrine secretory mechanism. (4) Ultrastructural alterations in the glandular cells confirmed our previous observation that copulation stimulates RNA and protein synthesis.     

Fine structure of the Nassonow's gland in the neotenic endoparasitic of female Xenos vesparum (Rossi) (Strepsiptera, Insecta)

Nassonow's gland consists of a number of cells with ducts that open on to the ventral surface of the brood canal in the cephalothoracic region of a neotenic female strepsipteran. The structural organization of the gland is reminiscent of the class 3 of the epidermal gland cells as defined by Noirot and Quennedey [Ann. Rev. Entomol. 19 (1974) 61], which consists of secretory and duct forming cells. The ultrastructure of the Nassonow's gland is described in female Xenos vesparum (Rossi) parasitic in the social wasp Polistes dominulus Christ. The large secretory cells are clustered in groups of three to four, rich in smooth endoplasmic reticulum and produce a secretion made up of lipids. In young females, just before mating, the ultrastructure of the cells and their inclusions indicate that they are active. In old-mated females the Nassonow's gland degenerates. Microvilli line an extracellular cavity and there are pores present in the irregularly thick cuticle of the efferent duct. The small duct forming cells, intermingle with epidermal cells, overlap secretory cells and produce a long efferent duct, the cuticle of which becomes thick close to its opening in the brood canal. Nassonow's gland could be the source of a sex pheromone, which might be capable of attracting the free-living male to a permanently endoparasitic female.     

Prenatal development of the palatine gland of rats

The present study aimed to elucidate the prenatal development of the rat palatine gland. Parasagittal 5 microm thick serial sections made from Wistar rats at embryonic days (E) 17 to 22 were stained with haematoxylin-eosin (HE), Alcian blue-Kernechtrot or immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU) as a marker of proliferating cells. Additionally, three-dimensional images of developing glandular parenchyma were reconstructed from serial HE sections with a personal computer. At E 17, several thickenings of the palatal epithelium had appeared which thereafter became the epithelial cords. Branching and lumenization commenced at E 20, and immature acini were observed at E 21. Three-dimensional reconstruction showed that the proximal part of the epithelial cord differentiated into the duct, and the distal part of the epithelial cord differentiated into the acinus. In immunohistochemical staining, there were many BrdU-positive cells in the epithelial cords including thickenings of the palatal epithelium, ducts, and acini. The BrdU labeling index of the cells of the epithelial cord was the highest (statistically significant) of the three in the primitive palatine gland. In conclusion, during the development of the rat palatine gland, epithelial cords with very high proliferative activity arise from the palatal epithelium, and then the proximal part of the epithelial cord differentiates into the duct, and the distal part of the epithelial cord differentiates into the acinus. Proliferation of these glandular parenchyma contributes to the growth of the developing palatine gland.     

Ultrastructure of secretion in the atrial gland of a mollusc (Aplysia)

Extracts of the atrial gland of the sea hare Aplysia californiea (Mollusca) induce egg laying when injected into mature individuals. Since egg laying is controlled endogenously by a peptide secreted by neuroendocrine cells in the central nervous system, the relationship between the atrial gland and these central neurons has become an issue of interest. With the particular objective of examining secretory structures we undertook an ultrastructural study of the atrial gland and adjacent tissues. This study revealed that the atrial gland epithelium is composed of two major cell types: ‘goblet-like’ exocrine cells containing large electron-dense granules, and ciliated ‘capping cells’. A non-secretory, and possibly post-secretory, cell containing electron-lucent granules was noted. A region of the large hermaphroditic duct contiguous to the atrial gland, known as the red hemiduct, also displayed capping cells and secretory cells with large granules. The content of these granules is organized into crista-like condensations. The cell also contains iron-rich pigment inclusions.     

Effect of testosterone on the female hamster harderian gland pigmentation and ultrastructure

Summary Distinct differences occur in the pigmentation and ultrastructural features of the Harderian glands in male and female hamsters. The results of a study on the effect of testosterone on the fine structure of the female Harderian glands are presented here. Glands from three groups of hamsters were examined at intervals up to 49 days: (1) testosterone injected, receiving 2mg testosterone propionate in 0.1 ml sesame oil per day; (2) sham-injected, receiving 0.1 ml sesame oil per day; (3) untreated controls. Testosterone injections caused a reduction in the number of dark-brown pigment granules in the acinar cells starting on the 6th day, whereas clusters of tubules, typical of adult male glands, appeared on the 4th day and increased in number thereafter. Lamellar structures, normally present in the female gland, decreased in testosterone treated specimens. These changes reversed after cessation of testosterone treatment. It is concluded that exogenous testosterone administered to female hamsters modifies the pigmentation and ultrastructure of their Harderian glands towards the male type and that this is a reversable phenomenon. There also appears to be an inverse relationship between the presence of tubular clusters in the acinar cells, and the degree of pigmentation.     

Migration of granulated metrial gland cells from cultured explants of mouse metrial gland tissue

Summary The migration of granulated metrial gland (GMG) cells from cultured explants of metrial gland tissue obtained from mice killed between days 10 and 16 of pregnancy has been studied. GMG cells migrated from all of the explants but more GMG cells were found around explants obtained from mice at day 10 of pregnancy than around explants obtained at later stages of pregnancy. The number of GMG cells found around each explant reached a peak at days 1, 2 or 3 of culture but only a few GMG cells were found around the explants by day 7 of culture.     

Ultrastructure and distribution of identified neurosecretory terminals in the sinus gland of the terrestrial isopod Oniscus asellus

An ultrastructural study of the sinus gland of the terrestrial isopod, Oniscus asellus, reveals that this structure consists of two regions: the bulb, which is attached by a narrow stalk to the optic lobe, and the lateral extension, which extends from the bulb along the optic tract to the compound eye. The bulb has a distal region containing only neurosecretory terminals, and a proximal region containing terminals, glial cells, and axons that give rise to the distally located terminals. In total, the sinus gland contains five types of terminals which can be distinguished by their location and the appearance of their neurosecretory granules. Three terminal types are located in the bulb and two in the lateral extension. The size of the terminals in the bulb varies among the three types, but the number of terminals is approximately the same for each type. Conversely, the two terminal types in the lateral extension are similar in size, but differ in number. Axons of two terminal types in the bulb can be traced to the central region of the protocerebrum; axons of one terminal type in the bulb and of terminals in the lateral extension can be traced to the optic lobe.     

Cell-specific mechanisms of estrogen receptor in the pituitary gland

Analysis of the mechanism of action of estrogen receptor shows protein and mRNA polymorphism within distinct pituitary receptor-positive cells. The lactotropes exhibit unique properties in these mechanisms that distinguish them from gonadotropes. Therefore, this cell type constitutes an especially interesting model in the male as well as in the female for estrogen receptor studies.Abbreviations PRL prolactin - E2 estradiol - ER estrogen receptor - GnRH gonadotropin releasing hormone - PMSG pugnant mare serum gonadotropin     

The opercular gland of the cleaner-wrasse Labroides dimidiatus (Labridae), a light-, electron and scanning electron microscopic investigation

A histological and ultrastructural examination of the opercular gland of the cleaner-wrasse Labroides dimidiutus has demonstrated that the slimy envelope which covers the animal at night is mainly produced by large mucous goblet cells in a folded epithelium; there is a high number of acidophilic secretory cells. At the ultrastructural level, both cell-types open at the surface of the epidermis. Preliminary experiments with pilocarpine, atropine and the α-blocker propranolol reveal a neural regulation of mucus discharge. Also, the rich vascularization of the gland could indicate a hormonal control e.g. by prolactin. The secretory products of both types of goblet cells are discussed in relation to their possible antibiotic properties.     

The effect of sex hormones on lipid content and mast cell number in the harderian gland of the female toad, Bufo viridis

The Harderian gland of the toad Bufo viridis is a dimorphic gland owing to the presence of lipid droplets in the female glandular cells present only during summer months. Ovariectomy causes the disappearence of sudanophilia and estrogen-treatment completely prevents this change, while testosterone-injection has little effect. Estradiol-treatment also provokes a proliferation of the interstitial connective tissue concomitantly with the mast cell number increase. Our results suggest that estradiol acts, stimulating both mast cell and connective tissue proliferation, and plays a role in determining the expression of the female type of the toad Harderian gland.