摘要:

AbstractSertoli cell nuclei are characterized by deep invaginations and, in addition, the orientation of the nuclei with respect to the wall of the seminiferous tubules varies during the cycle of the seminiferous epithelium. These events may be the result of cytoplasmic filaments acting at the level of the nuclear capsule and may represent significant changes in Sertoli cell activity. Thus, a study was performed to characterize the nature of the perinuclear filaments of Sertoli cells in vivo and in vitro.In Sertoli cells in vivo, microtubules and microfilaments were often detected in the perinuclear cytoplasm, and these cytoskeletal components were observed to course either parallel to, or abut at, the nuclear capsule. In Sertoli cells in vitro, the nuclear infoldings are retained and the perinuclear cytoskeleton was shown to contain microtubules, f‐actin, and intermediate filaments. A fixation‐permeabilization protocol employing tannic acid–saponin was used and it significantly enhanced the preservation of cytoskeletal components. The presence of f‐actin was demonstrated by using the S1 fragment of muscle myosin to decorate the microfilaments. Treatment of the cultured cells with either microtubule or f‐actin depolymerizing agents had no effect on nuclear shape. Thus, at present, the function of the prominent perinuclear cytoskeletal components remain

ISSN:1059-910X    

DOI:10.1002/jemt.1070200302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIdentification of the cytoskeletal elements and their role in the formation as well as the maintenance of head membrane compartmentalization is a much debated issue in mammalian spermatozoa. Data which have emerged during the last ten years are summarized. Those which have converged in a common opinion, such as the distribution of actin in mammalian spermiogenesis, are distinguished from those which have to be confirmed, such as the role of actin related proteins and actin in mature spermatozoa.

ISSN:1059-910X    

DOI:10.1002/jemt.1070200303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractActin has been characterized and localized in sperm cells of many mammals. Nevertheless, the reported localizations obtained by different methods and/or antibodies varied from species to species and even for the same species. To clarify the question, sperm actin distribution was reinvestigated under uniform technical conditions. Immunogold post‐embedding procedures were performed using a polyclonal and two monoclonal antibodies of known specificity to localize actin in spermatids and spermatozoa of rabbit, mouse, rat, monkey, and human. In these species, actin (F‐actin) was detected with the three antibodies between the nucleus and the acrosome of round and elongating spermatids. Species‐specific changes occurred in maturing spermatids. In the rabbit, actin labeling decreased and disappeared from the tip to the base of the subacrosomal layer. In testicular and epididymal spermatozoa actin was detected only with a monoclonal antibody (Amersham) successively in the neck, postacrosomal area, and subacrosomal bulges. In mouse late spermatids a transitory labeling of the neck was detected only with the polyclonal antiactin. In testicular and epididymal spermatozoa an actin labeling was observed in the principal piece of the tail. In rat, monkey, and human sperm cells actin remained undetected. These results suggest that there is a redistribution of actin in late spermatids and spermatozoa which is a species‐specific process but not an artifact of methodological origin. Thus, a function for actin in sperm, if any, remains to be demon

ISSN:1059-910X    

DOI:10.1002/jemt.1070200304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractWe have followed the fine structural distribution of two nucleosomal core histones, H2B and H3, and of protamines in the course of mouse spermiogenesis by means of specific antibodies and ultrastructural immunocytochemistry.Our results demonstrate that the nuclear labeling density of histone H2B decreases during steps 6–8 and then increases again in step 9–10 spermatids, while the labeling for histone H3 is constant throughout this period. In step 12 spermatids, the anti‐H2B antibody labels mainly the central area of the nucleus. The first signs of protamine labeling are present in step 12 spermatids, where the gold grains can be found over the periphery of the nucleus. Later on, protamine labeling constantly increases and, by the end of spermiogenesis, the whole nucleus is labeled.We suggest that the morphological and structural differences between the central area and the periphery of mouse spermatids are, at least partly, due to a difference in the protein moiety associated with DNA. The central area, which is peculiar to the mouse and has been previously considered as a focus of chromatin condensation, represents, however, the last nuclear region containing histones and consequently the last area where the substitution of histones by protamines takes

ISSN:1059-910X    

DOI:10.1002/jemt.1070200305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis experiment was conducted in Ile‐de‐France adult rams to examine the target point of a 2‐month light cycle regimen on seminiferous tubule functions, on intertubular compartment and on Leydig cell parameters. Eight rams were subjected to a 2‐month light cycle regimen and were compared to sexually active or inactive rams. In light‐treated rams, testis weight was maintained equal or was higher than that of sexually active rams. Both tubular and intertubular tissues were found significantly higher in light‐treated than in sexually active rams. The mean ratio of basement membrane area of the seminiferous tubules per Sertoli cells and the daily productions of A1 spermatogonia and of leptotene primary spermatocytes were significantly increased in light‐treated rams as compared with sexually active or inactive rams. Meanwhile, the dairy productions of diplotene primary spermatocytes, of round spermatids, of spermatozoa and of the rete testis fluid were not significantly increased in light‐treated as compared with sexually active rams but significantly greater than those of sexually inactive rams. Total volume, total numbers, and individual volumes of Leydig cells were at least equal or higher in light‐treated than in sex

ISSN:1059-910X    

DOI:10.1002/jemt.1070200306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe addition of 1% water to the epoxy resin Quetol increased the labeling intensity of the sample. The significant decrease of the curing temperature of the epoxy resin may assist in preservation of antigens. Water may also reduce the cross‐linkage of the resin allowing more antigen to be available to the antibodies. The modified Quetol resin is an option for use in immunocytochemistry studie

ISSN:1059-910X    

DOI:10.1002/jemt.1070200307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractCreatine phosphokinase regenerates ATP from ADP using creatine phosphate. Isoenzymes of creatine phosphokinase are bound to certain cellular structures or are compartmentalized in areas of the cell, and this has been used as a basis for defining the role of these isoenzymes in energy metabolism. The M isoenzyme of creatine phosphokinase has been morphologically associated with the M‐line of striated muscle in many species. In this present study the ultrastructural distribution and the relative concentration of the M form of creatine phosphokinase in human muscle tissue was determined using immunogold and electron microscopy. The M‐line of the sarcomere, comprising only 3—4% of the sarcomere area, was found to contain over 20% of the total M isoenzyme signal of the entire sarcomere. This technique represents a quantitative, ultrastructural method to study the subcellular distribution of this isoenzyme. These data suggest that localized concentrations of M‐CPK may be important for normal energy metabolism, and may also serve as a foundation for a better understanding of the relationship between abnormal creatine metabolism and the pathogenesis of neuromuscular

ISSN:1059-910X    

DOI:10.1002/jemt.1070200308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractInner ear tissue of the normal guinea pig was conductively stained (OTOTO‐method) for SEM investigations. The Hensen's cells of the organ of Corti were removed using a micromanipulator inside the SEM. By this method atypical bodies of sensory and supporting cells were revealed in the apical turns of the cochlea. Atypical sensory cells showed great variations in size and shape. Several had no contact to Deiter's cells and no or only one nerve supply at their basal end. Atypical Deiter's cells showed alterations in shape and in the form of their phalangeal processes.Additionally altered parts of the organ of Corti were isolated by micromanipulation and embedded for correlative TEM‐investigati

ISSN:1059-910X    

DOI:10.1002/jemt.1070200309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA method for correlative studies of early fertilization events that integrates techniques of intracellular electrophysiological recording, video‐imaging, and electron microscopy is described. A key feature of the method is its ability to identify the fertilizing sperm and to record the moment of egg excitation. Since the site of gamete interaction is recognizable throughout all stages of preparation, difficulties associated with locating the site of fertilization and determining specimen orientation for microtomy and electron microscopic examination are eliminated. Virtually all samples yield useful information. An example of interacting gametes fixed 4 sec after initiation of the fertilization potential and serial sectioned is described. The method is applicable to systems other than fertilizing eggs when functional, temporal, and spatial relationships of individual cells need to be correlated with changes in ultrastructur

ISSN:1059-910X    

DOI:10.1002/jemt.1070200310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractUsing the method of rapid freezing and freeze‐substitution, the embryonic chick cardiac muscle was investigated by transmission electron microscopy. Initially, the intercellular junctional complexes (fasciae adherentes and desmosomes) were formed in close proximity to each other along a nearly straight line. Subsequently, the separation of fasciae from desmosomes took place to form intercalated discs. The cell membranes of fasciae adherentes were reinforced with highly interwoven fine fibrils at which myofibrils terminated. The intercellular space of fasciae was bridged with fine fibrillar structures seemingly connected by a thin line at their middle portions. In the intercellular space of desmosomes, central lamina and traversing filaments were clearly observed. The outer and inner leaflets of the desmosomal plasmalemma were asymmetrically differentiated; the outer leaflet was thinner than the inner leaflet. On the inner side of the cell membrane, an electron‐lucent layer and a dense desmosomal plaque were observed. The latter structure had protrusions with less electron density towards the cytoplasmic side. Further inside, a meshwork of fine fibrils was seen along and toward which bundles of intermediate filaments ran. The results obtained with freeze‐substitution appeared to provide more information than those with thin sections after conventional fixation or with replicas of chemically fixed/glycerinated or physically fixed/deep‐etched ma

ISSN:1059-910X    

DOI:10.1002/jemt.1070200311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY