Patterns of protein synthesis during the germination of pea axes,and the effects of an interrupting desiccation period

As germination of axes of Pisum sativum L. seeds progressed, profound quantitative and qualitative changes occurred in the patterns of protein synthesis. This was shown by fluorography of gels following two-dimensional polyacrylamide gel electrophoresis separation of [³⁵S]methioninelabelled proteins. The effects of desiccation during germination on these in-vivo protein-synthesis patterns were followed. Desiccation differentially affected the synthesis of proteins. Usually, however, upon rehydration following desiccation the types of proteins being synthesized were recognizable as those synthesized earlier during imbibition of control, once-imbibed axes: seeds imbibed for 8 h, and then dried, did not recommence synthesis of proteins typical of 8-h-imbibed control seeds, but rather of 4-h-imbibed control seeds. Seeds imbibed for 12 h, and then dried and rehydrated, synthesized proteins typical of 4-h-and 8-h-control seeds. Thus drying of germinating pea axes caused the proteinsynthesizing mechanism to revert to producing proteins typical of earlier stages of imbibition. Drying during germination never caused the seed to revert to the metabolic status of the initial mature dry state, however.Abbreviation DR dried and rehydrated     

Colocalization of α-lactalbumin and a major casein in secretory vesicles of rat mammary epithelial cells

Summary Whether both casein and noncasein (serum or whey) proteins of milk are contained within the same secretory vesicles of milk secreting mammary epithelial cells was explored. Antibodies to a major casein and to -lactalbumin of rat milk were localized in thin sections with colloidal gold-conjugated second antibodies. Antibodies to the casein component bound to an antigen present within lumina of Golgi apparatus cisternae and within secretory vesicles. This antigen was also recognized in structures within secretory vesicles and within alveolar lumina which were ultrastructurally identified as casein micelles. Antigens recognized by antibodies to -lactalbumin also were present in Golgi apparatus cisternae and within secretory vesicles. Both anti-casein and anti--lactalbumin antibodies recognized antigens within the same secretory vesicles. These observations show that one major noncasein protein of rat's milk is present in casein-containing secretory vesicles.     

树鼩(Tupaia belangeri chinensis)精子发生的细胞学观察

对8只成体树鼩的睾丸进行了精子发生的细胞学和动力学观察。精原细胞可区分为A型和已分化定向的B型。生精上皮周期可分为12个连续阶段,不同阶段典型的细胞组合可被辨认。各阶段的相对持续时间以阶段Ⅴ、Ⅵ、Ⅶ的比率最高,分别为11.43,18.88、15.44;阶段Ⅸ、Ⅹ最低,为3.78和3.87。A型精原细胞在各阶段的数量分布并不保持恒定,阶段Ⅵ—Ⅷ和阶段Ⅸ时,分别出现两次成倍增长。B型精原细胞和前细线期精母细胞与每100个足细胞之比的平均值,在阶段Ⅰ、Ⅴ、Ⅶ分别为28.89、76.98、196.91。精细胞经14步变态为成熟精子。精子形成过程中顶体发育的形态学变化及成熟精子的形态,与灵长类动物相比具有较多的类似之处;而同啮齿类动物相比,存在明显的形态差异。     

Epithelial differentiation at the edentulous alveolar ridge in man

Summary The epithelial lining of the mucosa of the edentulous, maxillary alveolar ridge was subjected to an ultrastructural and stereological analysis. Four biopsies collected from the non-inflamed crest, i.e., the center over former tooth sockets, in non-denture-wearing female patients 30 to 55 years of age were processed for light and electron microscopy. At the light-microscopic level, epithelial thickness was determined histometrically. Electron micrographs were sampled at two levels of magnification, from five strata in regions of epithelial ridges and from three strata over connective tissue papillae. Standardized stereological pointcounting techniques were employed to analyze a total of 990 electron micrographs. Observations and data revealed that at the alveolar ridge the oral epithelium is truly keratinizing and comprises four strata including a 40±5 m-thick stratum corneum, which displays the oral keratin pattern. The histoand cytodifferentiation were peculiar: (1) Compared to the neighbouring gingival and hard palate epithelium, that of the alveolar crest was markedly thicker, with elongated rete ridges indicating acanthosis. (2) The cytoarchitecture was identical neither to the gingival nor to the hard palate epithelium but revealed a mixture of features typical for either of these two epithelia. Reasons for this are explained on the basis of factors, possible genetic, inherent in epithelial cells that are possibly derived from both the gingival and the palatal environment.     

Computer-aided three-dimensional reconstructions of the arrangement of primary spermatocytes in human seminiferous tubules

Summary With the use of a digital image-processing method three-dimensional reconstructions of the arrangement of spermatocytes in human seminiferous tubules were performed. With this method it was possible to investigate the cellular distribution in the tubule in nearly any given perspective and projection. In addition, by means of simple mathematical procedures, such as by transformation of Cartesian coordinates into cylindrical coordinates, it was possible to vary the shape of a reconstruction, i.e., to convert the cylindrical image of a tubular portion into a right-angled r--z-representation.The present work not only confirms the existence of a complex helical plan of organization of the human seminiferous epithelium but also provides further aspects of the phenomenon of physiological germ-cell loss and its integration into the kinetics of spermatogenesis.Dedicated to Prof. E.C. Roosen-Runge, Seattle, on the occasion of his 75th birthday     

Early ontogeny of Adinia xenica (Pisces,Cyprinodontiformes): 3. Comparison and evolutionary significance of some patterns in epigenesis of egg-scattering,hiding and bearing cyprinodontiforms

Synopsis Developmental patterns as seen in cyprinodontiforms fishes with different reproductive styles are compared, and discussed in relation to ecology and evolutionary significance. The discussion centres around Adinia xenica (its detailed ontogeny presented in two previous sequels to this paper), and, from the existing literature, Fundulus heteroclitus (closely related), Austrofundulus myersi (an annual) and Platypoecilus maculatus (a livebearer). The embryonic resting interval is present in various forms in the first three species, and differences in it and the overall patterns of development are shown to be consistent with ecological conditions. Termination of the resting interval leads immediately to hatching, a process in A. xenica, as in F. heteroclitus, apparently initiated by the appropriate summation of internal and external factors. These factors include any or all of: metabolic changes and increased oxygen requirements, response to light, reduced environmental oxygen, agitation, and increased hydrostatic pressure. They all can cause increased movement by the embryo which is credited with rupturing hatching gland cells and releasing the enzyme(s). Annual fishes experience 3 pronounced resting intervals, termed diapauses. These are discussed in the context of apparent steps and thresholds, and evolutionary ecology. A possible evolutionary sequence, from a simple fractional spawning pattern to diapause, is presented. Morphological differences in primary embryonic respiratory surfaces, as seen in the four species, are related to environmental conditions. The above illustrate ways in which the same basic structures and events are modified to cope with different habitats.     

Some factors controlling cell polarity in chick retinal pigment epithelial cells in clonal culture

In clonal culture differentiated chick retinal pigmented epithelial (RPE) cells form a monolayer which shows little or no cellular division. The cells usually rest on a basal and reticular lamina and are polarized with their apical surface towards the medium. The apical surface is characterized by apical protrusions, an extensive apical web of microfilaments and junctional complexes which join the apical-lateral borders. A PA/S positive material with a felt-like appearance from the serum component of the medium coats the surfaces of the tissue culture plates. A similar material is found on any membrane filter which has been exposed to medium containing serum. When such a filter brought in contact with the upper surfaces of the RPE cells, the apical surface characteristics are lost, the cells often accumulate Alcian Blue positive material between the cells and the filter and secrete a reticular and a basal lamina, i.e. they establish a second basal surface. Once this has occurred, the cells appear to either detach from the plate and reverse their polarity, or undergo division forming two cell layers. In the latter case new apical surfaces are created between the cell layers but the cells appear to join to form circular structures rather than sheets. These results suggest that contact with this felt-like material initiates formation of a basal surface. They further suggest that where the apical surface has been converted to a basal one the cell attempts to restore the apical surface either by separating from the plate and reversing its polarity or by creating circular structures and developing new apices oriented toward the center of the circle.     

The cell coat of the olfactory epithelium proper and vomeronasal neuroepithelium of the rat as revealed by means of the Ruthenium-red reaction

Summary The apical cell coat of the olfactory epithelium proper and the vomeronasal neuroepithelium of the rat was investigated electronmicroscopically by means of the Ruthenium-red reaction. In the olfactory epithelium proper, the cilia of receptor cells and microvilli of supporting cells possess a cell coat measuring approximately 10 nm in thickness. In the vomeronasal neuroepithelium, the apical cell coat is thicker than in the olfactory epithelium proper. On microvilli of vomeronasal receptor cells the cell coat varies in thickness from 15 to 20 nm, and on microvilli of supporting cells it measures approximately 75 nm. The functional implications of these findings are discussed.A portion of this study was presented at the 6^th European Anatomical Congress in Hamburg. This publication is dedicated to Prof. E. KlikaSupported by the Deutsche Forschungsgemeinschaft (Br 358/5-1).     

Granular “endocrine” cells in avian respiratory epithelia

Summary An electron microscopic investigation of the extrapulmonary respiratory tract of embryos and chick of the domestic fowl (Gallus domesticus) has demonstrated for the first time in birds the presence here of a small number of epithelial cells characterised by an aminecontaining type of granule. These granular cells were scattered singly throughout the trachea, syrinx and primary bronchi and seemed more numerous in the caudal part of the airway. In favourable planes of section a small part of the cell was in contact with the luminal surface of the epithelium. The characteristic granular vesicles (approximate diameter 140 nm) appeared to be randomly distributed in the cytoplasm and there was no concentration of vesicles close to the plasma membrane. One of the cells was closely associated with an intraepithelial axon. By fluorescence microscopy, a small number of cells with a similar shape and distribution to the granular cells was observed after administration of 3,4-dihydroxyphenylalanine which may indicate the presence of an amine handlign mechanism in these cells. It is suggested that the granular cells belong to the APUD system of endocrine cells and that they may be modulated by the concentration of gas in the airways.