摘要:

AbstractThe fine structure of the Golgi apparatus in rat spermatids at various steps of spermiogenesis was investigated in routinely stained preparations as well as in sections stained with the periodic acid‐silver technique for the demonstration of glycoprotein.In steps 1–7 spermatids, a layer of cisternae of endoplasmic reticulum envelops the Golgi apparatus. Between this layer and the stack of Golgi saccules, small coated vesicles (500–600 Å) are associated with smooth‐surfaced tubular profiles. These are irregular expansions of the first or outermost Golgi saccule. The next few saccules of the stack are regularly arranged and similar to one another. The last or innermost saccule is thick and produces coated buds, similar to the large coated vesicles (900–1200 Å) which are found nearby. Large smooth vesicles with a dense core, known as proacrosomic vesicles, are also found in this location at steps 1 and 2. These at step 3 fuse into the single acrosomic vesicle, which in turn at step 5 transforms into the head cap (while the dense core of the vesicles becomes the acrosomic granule).Using the PA‐silver technique on steps 1–7 spermatids, a gradation of staining is observed in Golgi saccules, with the most intense reaction in the innermost saccule, its coated buds and the large coated vesicles nearby. Intense staining is also noted in the head cap, while staining of lesser intensity is observed in the acrosomic granule.In older spermatids (steps 8–18) the Golgi apparatus gradually loses most of the features just described and appears to consist primarily of stacks of saccules with dilated edges. These are only weakly stained by the PA‐silver technique.These observations are interpreted as follows. Material produced in the endo‐plasmic reticulum would be transferred by small coated vesicles to the outermost saccule of the Golgi stacks. During saccule migration toward the inner aspect of the stacks, the synthesis of glycoprotein would be completed. The transfer of this glycoprotein via the large coated vesicles would cause the proacrosomic vesicles to grow into the acrosomic vesicle which later woul

ISSN:0002-9106    

DOI:10.1002/aja.1001300302

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe motor and cutaneous nerves associated with the pigeon's anterior latissimus dorsi tonus muscle are described. The motor nerve is traced from its origin within the brachialis longus superior nerve of the brachial plexus to within the epimysium of the muscle by means of serial cross sections. The nerve fibers differ in mean diameter at various sites along the nerve. They originate as small fibers within the plexus, become larger as they emerge and then gradually decrease in diameter as they approach the muscle. The number of nerve fibers remains relatively constant until the nerve divides into more than two branches, at which time the number increases.The cutaneous nerve passing through the anterior latissimus dorsi is described and is assumed not to play any role in the innervation, either sensory or motor, of the fibers in this muscle.

ISSN:0002-9106    

DOI:10.1002/aja.1001300303

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

年代:1971

数据来源: WILEY

摘要:

AbstractBoth short and long intermediate segments are found in the opisthonephric kidney of the adult sea lamprey and they possess morphologically distinct cell types. Wide lateral intercellular spaces appear between both the cuboidal cells of short segments and the squamous cells of long segments. Periodically the epithelium of the long segment is reduced in thickness providing for a close relationship between the interstitium and the tubular fluid. These features indicate that the segment may be involved in urine formation.The distal segment is divisible into two distinct portions: a straightpars rectaand a twistedpars convoluta.The cuboidal cells of the pars recta and the columnar cells of the pars convoluta are characterized by abundant smooth endoplasmic reticulum and mitochondria, features reminiscent of cells involved in ion transport. Multivesicular bodies, coated vesicles, and dense apical tubules suggest that cells of both regions may also be involved in endocytosis.The cells of the collecting segment have few organelles but they possess a cytoskeleton of coarse filaments and wide intercellular spaces.The parallel arrangement of the intermediate, distal, and collecting segments and of the blood vessels within the adult kidney is suggestive of a functional unit similar to that found in the medulla of the mammalian kidney.

ISSN:0002-9106    

DOI:10.1002/aja.1001300304

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

年代:1971

数据来源: WILEY

摘要:

AbstractAdrenergic nerve elements in the hypogastric ganglion of the guinea pig were studied by fluorescence and electron microscopy. The ganglion contains two main elements exhibiting green to green‐yellow fluorescence for catecholamines. One consists of basket‐like, simple nerve endings around some of the ganglion cell bodies, and the other of small polyhedral cells with short axonic processes. Electron microscopy revealed the ultrastructure of these elements. The adrenergic nerve endings contain small granular vesicles, about 500 Å in diameter, as well as a few large granular and small agranular vesicles. They were more rare than the cholinergic endings, which contain numerous small agranular vesicles mixed with a few large granular vesicles. Both adrenergic and cholinergic endings submerge to a considerable depth into the cytoplasm of ganglion cells. The ganglion cells send spinous processes into these endings. The fluorescent polyhedral cells are probably in an intermediate position between adrenal medullary cells and ganglion cells. They contain numerous large granular vesicles. Their axonic processes extend for a short distance to end in close topographical relation to capillaries. According to the structure of the granulated vesicles, these cells were classified into four types. The function of the adrenergic elements in ganglionic transmission was discu

ISSN:0002-9106    

DOI:10.1002/aja.1001300305

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

年代:1971

数据来源: WILEY

摘要:

AbstractTwo series of chick embryos were treated with hydrocortisone in an attempt to demonstrate the influence of this hormone upon microfibrils found free in the tissue space surrounding the notochord. Embryos in series I were explanted on agar‐albumen medium and permitted to survive 1–24 hours after Ringer's solution or hydrocortisone had been pipetted onto the area vasculosa. Doses of hydrocortisone ranged from 5 μg to 1 mg. Series II embryos were similarly treatedin ovothrough a small shell “window” and then incubated 12 or 24 hours. All embryos were sacrificed at 72 hours incubation age. Ringer‐treated embryos in both series exhibited a rich tangle of early extracellular connective tissue fibrils (microfibrils) surrounding the notochord. One hour after treatment with hydrocortisone, embryos in series I showed a reduction in perinotochordal microfibrils. At four hours the effect was maximal and by 12 hours, recovery had been initiated, the morphology of which suggested a re‐organization of amorphous material and extracellular debris to form fibrillar structures. Twenty‐four hours after treatment, recovery was complete and hydrocortisone‐treated embryos exhibited perinotochordal fibril populations that were indistinguishable from Ringer‐treated specimens. The results of the series II experiments roughly parallelled those seen in series I but were somewhat less predictable.Possible modes of action of hydrocortisone on connective tissues and their relationship to the present study are discussed. It is suggested that the steroid may induce the release of a substance with an enzymatic activity capable of digesting microfibrils. This catabolic activity may be reflected as an inhibition of connective tissue production if it is assumed that microfibrils are precursors of larger, more mature fibrils. It is further suggested that since microfibrils are thought to contain connective tissue proteins, the initiation of microfibrillar reduction by hydrocortisone could indicate that this hormone may act in a similar manner on more mature connect

ISSN:0002-9106    

DOI:10.1002/aja.1001300306

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

年代:1971

数据来源: WILEY

摘要:

AbstractMicrofibrils in the notochordal sheath of chick embryos of two to four days incubation age were analyzed electron microscopically. Collagenase, trypsin, hyaluronidase and alpha amylase were administered to both “living” and “fixed” embryos. Living embryos were either explanted on an agar‐albumen growth medium or were allowed to survive within the shell during experimental procedures. Fixed embryos were immersed in Karnovsky's aldehyde fixative prior to enzyme digestion. Both living and fixed specimens yielded similar results.Control embryos possessed microfibrils of ca. 200 Å, ca. 100 Å and less than 100 Å in diameter in the notochordal sheath. The smaller fibrils (100 Å and less) were present in all regions of the sheath, but were especially concentrated near the notochordal boundary (basement) membrane. The larger fibrils (200 Å) were farther removed from the notochord. Flaky amorphous material was attached to all fibrils and was abundant especially in the inner region of the sheath.Collagenase produced elimination of the 200 Å microfibrils, but the smaller ones remained intact. Trypsin caused digestion of all fibrils. Hyaluronidase digested fibrils chiefly 100 Å and less in diameter. Alpha amylase was similar to hyaluronidase in digesting the small fibrils. This study supports the hypothesis that microfibrils are primarily mucopolysaccharide‐protein precursors of larger col

ISSN:0002-9106    

DOI:10.1002/aja.1001300307

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

年代:1971

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001300301

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

年代:1971

数据来源: WILEY