Ultrastructure of Spermatozoa of Elaphe schrenckii (Reptilia, Squamata)

2020 ◽  
Vol 27 (3) ◽  
pp. 149-155
Author(s):  
Shan-Shan Wang ◽  
Yu-Yan Lu ◽  
Chen-Hao Yao ◽  
Shuo Qi ◽  
Jian-Xin Cheng ◽  
...  
Keyword(s):  
Cross Section ◽  
Neck Region ◽  
Base Plate ◽  
Laminar Structure ◽  
Fibrous Sheath ◽  
Dense Bodies ◽  
Transmission Electron ◽  
Principal Piece ◽  
Distal Centriole ◽  
The Stability

Elaphe schrenckii (Serpentes, Colubridae), a kind of large nonvenomous snakes and great significance to maintain the stability of ecosystem in China. We provide detailed descriptions of the sperm microstructure and ultrastructure of E. schrenckii, experimented by light microscope and transmission electron microscope. The spermatozoon of E. schrenckii is filiform and consists of head and tail regions. The cross-section of acrosomal vesicle is always rounded and divided into medulla inside and cortex outside. The ultrastructure of acrosome complex observed the unilateral ridge, the single perforatorium, the perforatorium base plate, the epinuclear lucent zone, the subacrosomal space and the nuclear fossa at the end of nucleus connect the neck region. The neck region is short with the stratified laminar structure and observed the distal centriole and the proximal centriole are perpendicular and both consisted of nine triplets. Midpiece is long and observed the extracellular microtubules, the multilaminar membranec, the mitochondria with the dense bodies discontinuity distribting, the fibrous sheath, and the axoneme. The principal piece is after the annulus with no mitochondrias and the end piece with no mitochondrias neither the fibrous sheath. Our study contrasted the spermatozoa ultrastructure of 8 species belong to 5 families and 6 genera and added the sperm measurement compare, summarized that three Colubridae snakes are more similar than others momentarily but some specific characteristics in E. schrenckii and proved that the ultrastructure of sperm related to phylogeny in some ways.

The ultrastructure of the spermatozoon of the northern water snake, Nerodia sipedon (Colubridae, Serpentes), with phylogenetic considerations

1994 ◽  
Vol 72 (9) ◽  
pp. 1648-1652 ◽  
Author(s):  
B. G. M. Jamieson ◽  
L. Koehler
Keyword(s):  
Base Plate ◽  
Mature Spermatozoon ◽  
Boiga Irregularis ◽  
Nerodia Sipedon ◽  
Fibrous Sheath ◽  
Dense Bodies ◽  
Water Snake ◽  
Northern Water Snake ◽  
Distal Centriole ◽  
Electron Lucent

The ultrastructure of the spermatozoon of Nerodia sipedon conforms closely to that of other described snake sperm: it is filiform; the acrosome vesicle is in the form of a hollow, concentrically zoned cone that basally overlies a subacrosomal cone which invests the tapered anterior end of the nucleus; the putative perforatorium is a slender rod extending anteriorly from the subacrosomal cone; the midpiece contains dense bodies and mitochondria; the axonemal fibrous sheath extends anteriorly into the midpiece (squamate autapomorphy); 9 peripheral dense fibres surround the distal centriole and the axoneme in the midpiece, of which fibres adjacent to 3 and 8 are enlarged; and the endpiece lacks peripheral fibres and the fibrous sheath. The midpiece is very long (a synapomorphy of the Serpentes) and is surrounded by a multilaminar membrane (an autapomorphy). In the squamates, only snakes, including N. sipedon, retain microtubules external to the plasma membrane of the mature spermatozoon. Helically arranged zigzag mitochondria are shared (probably homoplasically) with iguanid sperm. A poorly developed "stopperlike" putative perforatorial base plate in N. sipedon, unknown in other snakes, is questionably homologous with that of gekkonids. An electron-lucent space caps the nuclear point, as in the snakes Boiga irregularis and Stegonotus cucullatus and in some other squamate orders.

scholarly journals OBSERVATIONS ON THE FINE STRUCTURE OF THE DEVELOPING SPERMATID IN THE DOMESTIC CHICKEN

1962 ◽  
Vol 14 (2) ◽  
pp. 193-205 ◽  
Author(s):  
Toshio Nagano
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Cross Section ◽  
Neck Region ◽  
Structural Features ◽  
Dense Granule ◽  
Domestic Chicken ◽  
The Other ◽  
Dense Structure ◽  
Distal Centriole

The kinetic apparatus, the acrosome and associated structures, and the manchette of the spermatid of the domestic chicken have been studied with the electron microscope. The basic structural features of the two centrioles do not change during spermiogenesis, but there is a change in orientation and length. The proximal centriole is situated in a groove at the edge of the nucleus and oriented normal to the long axis of the nucleus and at right angles to the elongate distal centriole. The tail filaments appear to originate from the distal centriole. The plasma membrane is invaginated along the tail filaments. A dense structure which appears at the deep reflection of the plasma membrane is identified as the ring. The fine structure of the ring has no resemblance to that of a centriole and there is no evidence that it is derived from or related to the centrioles. The tail of the spermatid contains nine peripheral pairs and one central pair of tubular filaments. The two members of each pair of peripheral filaments differ in density and in shape: one is dense and circular, and the other is light and semilunar in cross-section. The dense filaments have processes. A manchette consisting of fine tubules appears in the cytoplasm of the older spermatid along the nucleus, neck region, and proximal segment of the tail. The acrosome is spherical in young spermatids and becomes crescentic and, finally, U-shaped as spermiogenesis proceeds. A dense granule is observed in the cytoplasm between acrosome and nucleus. This granule later becomes a dense rod which is interpreted as the perforatorium.

The ultrastructure of the spermatozoa of the worm lizard Amphisbaena alba (Squamata, Amphisbaenidae) and the phylogenetic relationships of amphisbaenians

1999 ◽  
Vol 77 (8) ◽  
pp. 1254-1264 ◽  
Author(s):  
Ruscaia D Teixeira ◽  
Guarino R Colli ◽  
Sônia N Báo
Keyword(s):  
Transverse Section ◽  
Base Plate ◽  
Sister Group ◽  
Mature Spermatozoon ◽  
Fibrous Sheath ◽  
Dense Bodies ◽  
Intrafamilial Variability ◽  
Anatomical Characters ◽  
Phylogenetic Hypotheses ◽  
Constraint Tree

We describe the ultrastructure of epididymal spermatozoa of Amphisbaena alba and make comparisons with spermatozoa of other squamates. The mature spermatozoon of A. alba is filiform and characterized by the following features: the acrosome is depressed in transverse section; the perforatorial base plate is absent; the perforatorial tip is pointed; the perforatorium is single; the epinuclear lucent zone is well developed; the midpiece is moderately long; the mitochondria are columnar, forming regular circlets interrupted by dense bodies in transverse section; the dense bodies are solid, arranged in regular rings and linear series; the nuclear shoulders are rounded; the nucleus is elongate; the endonuclear canal is absent; fibers 3 and 8 are enlarged; multilaminar membranes are absent; and the fibrous sheath is in the midpiece. A phylogenetic analysis of squamates using spermatozoon-ultrastructure characters resulted in 2415 equally parsimonious, largely unresolved trees. The use of a constraint tree derived from gross anatomical characters suggested that the Amphisbaenia is the sister-group of the Autarchoglossa. We conclude that to improve the resolution of phylogenetic hypotheses derived from spermatozoon-ultrastructure characters, the number of characters ought to be increased, and more investigations are necessary to ascertain the degree of intrafamilial variability.

Ultrastructure of the spermatozoon of the tuatara ( Sphenodon punctatus ) and its relevance to the relationships of the Sphenodontida

1992 ◽  
Vol 335 (1274) ◽  
pp. 193-205 ◽  
Keyword(s):  
Posterior Extremity ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Electron Microscopic ◽  
Fibrous Sheath ◽  
Sphenodon Punctatus ◽  
Principal Piece ◽  
Distal Centriole ◽  
Material Form ◽  
Complex Length

Spermatozoa of the New Zealand tuatara , Sphenodon punctatus punctatus (Gray), are described from light and electron microscopic observations and compared with spermatozoa of other living ‘reptiles’ (Chelonia, Crocodilia, Squamata), birds and mammals. Mature Sphenodon spermatozoa consist of an acrosomal complex (length 4 µm), elongate, helical nucleus (54-56 µm), a relatively short midpiece (7-8 µm), elongate principal piece (74-78 µm) and short end piece (2-4 µm). The acrosomal vesicle and underlying subacrosomal material form a double, curved, conical sheath around the nucleus anteriorly. Two parallel, loosely helical, endonuclear canals each containing perforatorial material, extend posteriorly from the apex of the nucleus to at least 2.5 µm below the base of the acrosomal complex. Rings of several spherical mitochondria are stacked around the elongate distal centriole to form the midpiece. Each mitochondrion has concentric cristae surrounding a dense central body. Proximal and distal centrioles, although differing markedly in length, are similar in having triplets with an open C tubule. Nine peripheral fibres are intimately associated with the triplets of the distal centriole. A well developed annulus defines the posterior extremity of the midpiece. The principal piece consists of a 9 + 2 axoneme (accompanied anteriorly by nine peripheral fibres) surrounded by a highly electron-dense fibrous sheath and the plasma membrane. Absence of a penis in Sphenodon has not resulted in recognizable modifications of the spermatozoon. Sphenodon shares many spermatozoal features here interpreted as plesiomorphies with crocodiles and turtles, particularly the latter group, but exhibits none of the advanced character states (apomorphies) diagnostic of the Squamata. These data not only underscore the primitive status of living tuatara (recently questioned in the literature) but also militate against a close, sister-group relationship between the Sphenodontida and Squamata.

The ultrastructure of spermatogenesis and epididymal spermatozoa of the tuatara Sphenodon punctatus (Sphenodontida, Amniota)

1994 ◽  
Vol 344 (1308) ◽  
pp. 187-199 ◽  
Keyword(s):  
Early Stage ◽  
Dense Body ◽  
Nuclear Surface ◽  
Epididymal Sperm ◽  
Fibrous Sheath ◽  
Acrosomal Vesicle ◽  
Lateral Body ◽  
Sphenodon Punctatus ◽  
Principal Piece ◽  
Distal Centriole

By using transmission electron microscopy (TEM) the events of spermatogenesis are described for the first time in the tuatara Sphenodon punctatus punctatus (Gray), a representative of the ‘reptilian’ order Sphenodontida. Secondary spermatocytes contain two greatly elongate (8.0 μm), rod-shaped centrioles which lie parallel to one another and are each associated with a small deposit of dense material and a short centriole. Spermatids contain only one rod-shaped centriole (associated with a short centriole) which gives rise to the flagellar axoneme thereby becoming the distal centriole. Four stages of spermatid development can be distinguished: (i) the early stage (nucleus round; nuclear contents granular with a thin, condensed periphery; mitochondria scattered; acrosomal vesicle spheroidal, slightly depressed onto nuclear surface); (ii) the middle stage (nucleus pyriform with two endonuclear canals formed; nuclear contents fibro-granular with thick periphery; mitochondria chiefly posterior; acrosomal vesicle flattened; centriolar complex attached to nucleus); (iii) the advanced stage (nucleus elongate and rod shaped; nuclear contents coarsely granular; mitochondria (containing linear cristae) clustered around the distal centriole; acrosomal vesicle conical; centriolar complex attached to posterior fossa of nucleus); (iv) the late stage (nucleus very elongate and associated with a longitudinally arranged microtubular sheath; nuclear contents very condensed; midpiece fully formed and featuring mitochondria with concentric cristae and a dense intramitochondrial body; centrioles associated with a dense, lateral body). Testicular sperm have a conical acrosomal vesicle (length 4 μm) and subacrosomal cone, an elongate (length 54- 56 μm) helical nucleus, a midpiece (length 8 μm, featuring spheroidal mitochondria containing concentric cristae and a dense body), an annulus, an elongate principal piece (length 74-78 μm, featuring a dense, fibrous sheath) and a short end piece (length 2-4 μm). Epididymal sperm differ from those in the testis by having a more developed lateral body in the midpiece and a sheath of flocculent material surrounding the fibrous sheath in the principal piece. The relatively large number of epididymal sperm still associated with a cytoplasmic droplet suggests that sperm spend a significant period maturing within the epididymis. The features of spermatogenesis and mature sperm suggest that the Sphenodontida are primitive amniotes, with only chelonians having fewer spermatozoal apomorphies while the crocodilians are little more advanced.

Copper Localization in Cirrhotic Rat Liver by Scanning Electron Microscopy

1969 ◽  
Vol 27 ◽  
pp. 38-39 ◽  
Author(s):  
J. C. Russ ◽  
E. McNatt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Copper Acetate ◽  
Lead Citrate ◽  
Dense Bodies ◽  
Transmission Electron ◽  
Electron Mode ◽  
Scanning Electron

In order to study the retention of copper in cirrhotic liver, rats were made cirrhotic by carbon tetrachloride inhalation twice weekly for three months and fed 0.2% copper acetate ad libidum in drinking water for one month. The liver tissue was fixed in osmium, sectioned approximately 2000 Å thick, and stained with lead citrate. The section was examined in a scanning electron microscope (JEOLCO JSM-2) in the transmission electron mode.Figure 1 shows a typical area that includes a red blood cell in a sinusoid, a disse, and a portion of the cytoplasm of a hepatocyte which contains several mitochondria, peribiliary dense bodies, glycogen granules, and endoplasmic reticulum.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 70-71
Author(s):  
Brian L. Rhoades
Keyword(s):  
Cross Section ◽  
Reaction Chamber ◽  
Objective Lens ◽  
Reduced Cross Section ◽  
Cross Sectional ◽  
Structural Investigations ◽  
Transmission Electron ◽  
Dynamic Experiments ◽  
Successful Design ◽  
Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

The use of an energy-filtering electron microscope to reduce chromatic aberration in images of thick biological specimens

1986 ◽  
Vol 44 ◽  
pp. 88-91
Author(s):  
L. D. Peachey ◽  
J. P. Heath ◽  
G. Lamprecht
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Cross Section ◽  
Electron Scattering ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Incident Electron Energy ◽  
Energy Filtering ◽  
Transmission Electron

Biological specimens of cells and tissues generally are considerably thicker than ideal for high resolution transmission electron microscopy. Actual image resolution achieved is limited by chromatic aberration in the image forming electron lenses combined with significant energy loss in the electron beam due to inelastic scattering in the specimen. Increased accelerating voltages (HVEM, IVEM) have been used to reduce the adverse effects of chromatic aberration by decreasing the electron scattering cross-section of the elements in the specimen and by increasing the incident electron energy.

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