Electron microscopic study of sperm head differentiation in the lizard Agama stellio

Early differentiation of the spermatid of Agama stellio is demonstrated by two anterior nuclear depressions, occupied by two proacrosomal vesicles, which fuse to form one vesicle. Later, this vesicle exhibits an acrosomal granule in its midposterior portion. The space between the posterior acrosomal membrane and the nuclear envelope is occupied by a subacrosomal fibrous layer which later exhibits a subacrosomal granule posterior to the acrosomal granule. The acrosomal vesicle and the nuclear depression flatten and later elongate. The acrosomal granule spreads and assumes the inverted V shape of the acrosomal vesicle, and the subacrosomal material assumes a feathery shape capping the nuclear prolongation. The subacrosomal granule on top of this feathery material forms a long, cross-striated subacrosomal rod which extends towards the tip of the acrosome. The chromatin material undergoes condensation into spirally oriented fibers, which eventually become homogeneous and dense. This process is accompanied by a change in the orientation of the manchette microtubules, which initially occur as rings around the nucleus and are eventually found parallel to the longitudinal axis of the nucleus.

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An electron microscopic study of the formation and structure of the periostracum in Astarte (Bivalvia)

Canadian Journal of Zoology ◽

10.1139/z74-188 ◽

1974 ◽

Vol 52 (12) ◽

pp. 1463-1471 ◽

Cited By ~ 33

Author(s):

A. S. M. Saleuddin

Keyword(s):

Microscopic Study ◽

Electron Microscopic Study ◽

Cell Types ◽

Homogeneous Layer ◽

Fibrous Layer ◽

Electron Microscopic ◽

The Third ◽

Thin Sectioning ◽

Structural Details ◽

Different Cell Types

An electron microscopic study of the outer and middle folds of the mantle edge of Astarte castanea reveals the fine-structural details of the cells which are involved in the formation of the periostracum. There are four types of cells in the outer fold whereas there is only one type in the middle fold. The role of different cell types in the formation of the periostracum has been discussed. The periostracum originates in the intercellular space between the basal cell of the outer fold and the first cell of the middle fold. Even at the point of origin it consists of two outer membranous layers and the inner dark homogeneous layer. The fibrous translucent layer, which is the third layer of the fully mature periostracum, does not appear until the young periostracum has moved down the periostracal groove at the level of the third cell. As the periostracum matures, the two membranous layers remain remarkably constant in width, whereas the two inner layers, dark homogeneous and fibrous translucent, increase in thickness. Scanning electron microscopy and thin sectioning reveal that the fully mature periostraca of A. castanea and A. elliptica appear uniformly pitted, but the nature of the pits between the two species is different. The fibrils of the fibrous layer show either uniform or random arrangements, depending on the region. It is the innermost part of the fibrous layer of the periostracum that provides the nuclei for calcification.

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Electron Microscopic Study of Sperm Head Differentiation in the Arabian Horned Viper Cerastes cerastes (Squamata, Reptilia)

Journal of Biological Sciences ◽

10.3923/jbs.2004.111.116 ◽

2004 ◽

Vol 4 (2) ◽

pp. 111-116 ◽

Cited By ~ 9

Author(s):

O.A. Al-Dokhi .

Keyword(s):

Microscopic Study ◽

Electron Microscopic Study ◽

Sperm Head ◽

Electron Microscopic

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The Growth of Herpesvirus mulatto in Human Fibroblast

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051232 ◽

1974 ◽

Vol 32 ◽

pp. 244-245

Author(s):

Glennelle Washington ◽

Philip P. McGrath ◽

Peter R. Graze ◽

Ivor Royston

Keyword(s):

Rhesus Monkey ◽

Microscopic Study ◽

Electron Microscopic Study ◽

Peripheral Blood ◽

Human Fibroblast ◽

Rhesus Monkeys ◽

Human Fibroblasts ◽

Electron Microscopic ◽

Specific Antisera ◽

Peripheral Blood Leucocytes

Herpes-like viruses were isolated from rhesus monkey peripheral blood leucocytes when co-cultivated with WI-38 cells. The virus was originally designated rhesus leucocyte-associated herpesvirus (LAHV) and subsequently called Herpesvirus mulatta (HVM). The original isolations were from juvenile rhesus monkeys shown to be free of antibody to rhesus cytomegalic virus. The virus could only be propagated in human or simian fibroblasts. Use of specific antisera developed from HVM showed no relationship between this virus and other herpesviruses. An electron microscopic study was undertaken to determine the morphology of Herpesvirus mulatta (HVM) in infected human fibroblasts.

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Cell Wall Ultrastructure in Three Strains of a Cariogenic Streptococcus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065730 ◽

1971 ◽

Vol 29 ◽

pp. 338-339

Author(s):

M. J. Kramer ◽

Alan L. Coykendall

Keyword(s):

Cell Wall ◽

Dental Caries ◽

Streptococcus Mutans ◽

Microscopic Study ◽

Electron Microscopic Study ◽

Genetic Heterogeneity ◽

Morphological Characteristics ◽

Electron Microscopic ◽

Dna Reassociation ◽

Wall Ultrastructure

During the almost 50 years since Streptococcus mutans was first suggested as a factor in the etiology of dental caries, a multitude of studies have confirmed the cariogenic potential of this organism. Streptococci have been isolated from human and animal caries on numerous occasions and, with few exceptions, they are not typable by the Lancefield technique but are relatively homogeneous in their biochemical reactions. An analysis of the guanine-cytosine (G-C) composition of the DNA from strains K-1-R, NCTC 10449, and FA-1 by one of us (ALC) revealed significant differences and DNA-DNA reassociation experiments indicated that genetic heterogeneity existed among the three strains. The present electron microscopic study had as its objective the elucidation of any distinguishing morphological characteristics which might further characterize the respective strains.

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A New Technique for the Light and Electron Microscopic Study of Individual Cerebro-Spinal Fluid Cells in a Mona Plane Layer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091792 ◽

1976 ◽

Vol 34 ◽

pp. 362-363

Author(s):

L.A. Dell

Keyword(s):

Microscopic Study ◽

Electron Microscopic Study ◽

Plane Layer ◽

Ultrastructural Level ◽

Spinal Fluid ◽

Electron Microscopic Level ◽

Electron Microscopic ◽

Easy Method ◽

Cell Pellet ◽

A New Technique

A new method has been developed which readily offers the microscopist a possibility for both light and electron microscopic study of selected cells from the cerebrospinal fluid. Previous attempts to examine these cells in the spinal fluid at the ultrastructural level were based on modifications of cell pellet techniques developed for peripheral blood. These earlier methods were limited in application by the number of cells in spinal fluid required to obtain a sufficient size pellet and by the lack of an easy method of cellular identification between the light and electron microscopic level. The newly developed method routinely employs microscope slides coated with Siliclad and tungsten oxide for duplicate cytocentrifuge preparations of diagnostic spinal fluid specimens. Work done by Kushida and Suzuki provided a basis for our use of the metal oxide.

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Vesicular system associated with spermiogenesis of bullfrog

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128377 ◽

1987 ◽

Vol 45 ◽

pp. 818-819

Author(s):

K. C. Liu ◽

S. F. Tsay

Keyword(s):

Electron Microscopy ◽

Microscopic Study ◽

Electron Microscopic Study ◽

Reproductive System ◽

Seminiferous Tubule ◽

Rana Catesbeiana ◽

Routine Procedure ◽

Electron Microscopic ◽

Twisted Tubules ◽

Electron Lucent

In the histologic and electron microscopic study of the male reproductive system of bullfrog, Rana catesbeiana, a vesicular system associated with spermiogenesis was observed. It appeared in the lumenal space of the seminiferous tubule (Fig. 1), in the heads of spermatids (Fig. 2), associated with the chromatins of the spermatid (Fig. 4). As deduced from sections, this vesicular system consisted of vesicles of various size or a large group of waving and twisted tubules (Fig. 3), After routine procedure of treatment for electron microscopy, the lumens of both of the vesicles and tubules were electron lucent.In human, vesicles and vesicular system associated with reproductive cell and tissue were reported. In abnormal spermiogenesis, flower-like body, actually vesicles, and giant vesicle associated with the head of spermatid were observed. In both cases the number of vesicle was limited from a single one to a few.

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