摘要:

SYNOPSISA description is given of the development of the acrosome and post‐nuclear cap of normal bull spermatozoa and of the abnormal “knobbed” spermatozoa of certain sterile bulls.The acrosome of the normal spermatid has two components—the “cap” and the “bead.” Evidence is presented that the acrosome of the mature spermatozoon has also two components—a PAS‐positive, silver‐negative component which is formed from the cap of the spermatid and a silver‐positive component which is formed from the bead. It is suggested that the equatorial segment is a gap between the silver‐positive component of the acrosome and the silver‐positive post‐nuclear cap.In “knobbed” spermatozoa the bead persists, the silver‐positive component of the acrosome is not formed and no equatorial segment is detectable.The development of the post‐nuclear c

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00442.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SYNOPSISThe morphological features of boar spermatozoa in freshly ejaculated semen and in semen exposed to various experimental treatments have been studied in stained smears and with the phase‐contrast microscope and the electron‐microscope.The spermatozoon of the boar closely resembles that of other domestic ungulates. The head is approximately 8.5μ long; it is twice as long as it is wide. The mid‐piece is approximately 10μ long and the main tail‐piece is 30μ long.The head is covered anteriorly by a cap‐like structure—the acrosome. Evidence is presented to show that the acrosome has two components: the outer acrosome is the larger, the smaller inner acrosome is a crescentic structure. The segment‐shaped area of overlap between the two parts of the acrosome forms the equatorial segment which is a feature of living boar spermatozoa.The surface of the head behind the acrosome impregnates with silver; this argentophil area is the post‐nuclear cap.Three neck granules can be distinguished at the posterior border of the head and these are apparently connected to three bundles of neck fibres which the head receives from the mid‐piece.The structure of the spermatozoon is altered by post‐mortem changes; the most prominent changes occur in the acrosome. Evidence is presented that the post‐nuclear cap is absent from dead spermatozoa.The development of the boar acrosome has been studied in sections stained by the PAS method and in unfixed tissues with the phase‐contrast microscope. The development of the post‐nuclear cap has been studied in sections impregnated with silver. The morphological features of epididymal spermatozoa have been studied in spermatozoa from different levels of the epididymis.The development of the acrosome is shown to resemble its development in the bull. Two separate components of the acrosome of the spermatid are distinguished. It is suggested that these develop into the two components of the acrosome of the mature spermatozoon.Migration of the cytoplasmic droplet from the neck to the mid‐piece occurs at varying levels in the epididymis, but it is shown that it may occur in the head of the epididymis.The findings are discussed in relation to current ideas about the stru

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00443.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SYNOPSISElectron micrographs of the dictyosomes and acroblasts of the male germ cells of the cricket reveal their ultramicroscopic structure to be comparable to that of the Golgi apparatus of vertebrates. They are made up of two components, namely, double membrane lamellæ and vacuoles. These results suggest that the dictyosomes and acroblasts (Golgi material) are real cellular structures, distinct from mitochondria and homologous to the Golgi apparatus in vertebrate cells

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00444.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SYNOPSISA new technique is presented for detecting Epsom salt adulteration in East India tanned leathers by microscopical examination.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00445.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SYNOPSISA new slit‐lamp microscope camera has been designed with a daylight spectral emission, a non‐stroboscopic flash unit, and a wide aperture lens system that enables photographs to be taken in colour of the transparent tissues of the human cornea, crystalline lens, lens capsule, lens nucleus in section, and with high magnificat

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00446.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

SYNOPSISThe value of a two‐stage replica method for the light microscopy of surfaces is stressed and the method of replication is briefly described. The replica is made in an optically homogeneous transparent plastic and is metal shadowed to give a more informative image of good contrast. An attractive feature of the method is that it also permits selected areas of a specimen to be studied in the electron microscop

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00447.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00448.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00449.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY

摘要:

Book reviewed in this article:Die Leitz‐werke.—Willi Erb.Modern Methods of Microscopy.—Edited by A. E. J. Vickers.Escape to Adventure.—N. Monkman.The Structure of Wood.—F. W. Jane. Adam&Charles BlackThe Marine and Freshwater Plankton.—

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1956.tb00450.x

出版商:Blackwell Publishing Ltd    

年代:1956

数据来源: WILEY