Electron microscope study of the effects of radiation on insect fertility

1990 ◽  
Vol 48 (3) ◽  
pp. 72-73
Author(s):  
Judy Ju-Hu Chiang ◽  
Robert Kuo-Cheng Chen
Keyword(s):  
Electron Microscopy ◽  
Germ Cell ◽  
Germ Cells ◽  
Electron Microscope Study ◽  
Radiation Treatment ◽  
Light And Electron Microscopy ◽  
Stem Borer ◽  
Metabolic Energy ◽  
Rice Stem Borer ◽  
Effects Of Radiation

Germ cells from the rice stem borer Chilo suppresalis, were examined by light and electron microscopy. Damages to organelles within the germ cells were observed. The mitochondria, which provide the cell with metabolic energy, were seen to disintegrate within the germ cell. Lysosomes within the germ cell were also seen to disintegrate. The subsequent release of hydrolytic enzymesmay be responsible for the destruction of organelles within the germ cell. Insect spermatozoa were seen to lose the ability to move because of radiation treatment. Damage to the centrioles, one of which is in contact with the tail, may be involved in causing sperm immobility.

scholarly journals An Electron Microscope Study of Basophile Substances of Frozen-Dried Rat Liver

1958 ◽  
Vol 4 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Henry Finck
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Rat Liver ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Freeze Drying ◽  
Light And Electron Microscopy ◽  
Enzyme Treatment ◽  
Dense Granules ◽  
Homogeneous Matrix

Small pieces of liver from rats subjected to different dietary regimes were fixed by freeze-drying, and postfixed by in vacuo heating and denaturation with alcohol. Specimens were digested with ribo- or deoxyribonuclease, and stained with gallocyanin-chromalum, azure II, the Feulgen procedure or alcoholic platinic tetrabromide. Some specimens were reserved as controls of the effects of enzyme treatment. Stained and unstained specimens were embedded in methacrylate and examined by light and electron microscopy. Basophilic and Feulgen-positive substances, after contact with watery reagents, were found by electron microscopy to exist as small dense granules embedded in a less dense homogeneous matrix, forming the walls of submicroscopic vacuoles. These granules were absent after digestion with nucleodepolymerases. In specimens (unstained, or stained with platinic tetrabromide) which had not passed through water, the dense (basophile) substances in nuclei and cytoplasm were found to exist, not as granules, but as ill defined submicroscopic concentrates which blended imperceptibly into the homogeneous matrix of the vacuolar walls. Objections to the use of stains for improving contrast conditions in electron microscopy of tissues are discussed, and it is concluded that the reagents do not necessarily produce the observed increases in contrast by selectively stabilizing certain structures. The concept of microsomes as pre-existing distinct morphological entities in intact (unhomogenized) cells is thought to be inconsistent with the distribution of basophile substances in frozen-dried liver.

Histological and quantitative changes in the annual testicular cycle of Triturus marmoratus marmoratus

1990 ◽  
Vol 68 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Francisco Jose Saez ◽  
Benito Fraile ◽  
Ricardo Paniagua
Keyword(s):  
Endoplasmic Reticulum ◽  
Germ Cell ◽  
Germ Cells ◽  
Primordial Germ Cells ◽  
Light And Electron Microscopy ◽  
Second Phase ◽  
Glandular Tissue ◽  
Quantitative Studies ◽  
Quantitative Changes ◽  
Triturus Marmoratus

Eight male marbled newts (Triturus marmoratus marmoratus) were collected on the 15th of each month in 1987 and their testes were studied by light and electron microscopy. Quantitative studies also were performed to establish the annual testicular cycle and the total volume per testis occupied by each germ cell type throughout the year. Characteristic ultrastructural features of germ cells are the occurrence of a well-developed Golgi complex in primary spermatogonia; multiple small dictyosomes and nuclear blebs in primary spermatocytes; peripherally situated mitochondria; long strands of endoplasmic reticulum and subsurface cisternae in round spermatids; and abundant rough endoplasmic reticulum in follicular cells. Secondary spermatocytes have a short or absent interphase and are observed in the prophase. The annual testicular cycle comprises three periods: (i) germ cell proliferation (May–June), characterized by the formation of primary spermatocytes that undergo meiosis, giving rise to round spermatids; (ii) spermiogenesis (July–September), during which round spermatids develop into spermatozoa and the interstitial boundary cells are transformed into glandular tissue cells; and (iii) testicular quiescence (October–April) in which the testis contains only spermatozoa, glandular tissue, and a few primordial germ cells and spermatogonia. In the second phase of testicular quiescence (February–April) spermatozoa are released from the testis and proliferation of secondary spermatogonia occurs.

The arrangement of germ cells in the rat seminiferous tubule: an electron-microscope study

1975 ◽  
Vol 19 (3) ◽  
pp. 487-507
Author(s):  
P.B. Moens ◽  
A.D. Hugenholtz
Keyword(s):  
Electron Microscopy ◽  
Germ Cells ◽  
Electron Microscope Study ◽  
Mitotic Cycle ◽  
Seminiferous Epithelium ◽  
Serial Sections ◽  
Cell Numbers ◽  
Large Size ◽  
Cytoplasmic Bridges ◽  
Spermatogonial Proliferation

The spermatogonia and early spermatocytes of 13 samples of rat seminiferous epithelium (about 0-05 mm2 each) were mapped from electron micrographs of serial sections. Clones of cells, connected by cytoplasmic bridges (syncytia of 2–100 cells), in various stages of spermatogenic development were identified. Maps of 7 separate areas are illustrated. It is concluded that, contrary to the models of spermatogonial proliferation based on light-microscope observations, regions of seminiferous epithelium which are identical in terms of spermatid and spermatocyte criteria have, in fact, quantitative and qualitative differences in their spermatogonial population. The data are interpreted that for a given epithelial area there is a periodic build-up of spermatogonia which then produce several successive quanta of spermatocytes and when the spermatogonia are depleted the process repeats. That cell numbers less than double following a mitotic cycle has generally been attributed to systematic degeneration. Evidence from electron microscopy indicates, however, that at the mitotic peaks not all the syncytia undergo division but that some remain arrested. Similarly, within a dividing syncytium a few cells do not divide while they advance developmentally with the syncytium as a whole. The observed large size of spermatocyte syncytia further argues against systematic degeneration with its attendant fragmentation of syncytia.

scholarly journals Loss of protein phosphatase 1cγ (PPP1CC) leads to impaired spermatogenesis associated with defects in chromatin condensation and acrosome development: an ultrastructural analysis

Reproduction ◽  
2010 ◽  
Vol 139 (6) ◽  
pp. 1021-1029 ◽  
Author(s):  
Nicole Forgione ◽  
A Wayne Vogl ◽  
Susannah Varmuza
Keyword(s):  
Electron Microscopy ◽  
Male Infertility ◽  
Germ Cells ◽  
Chromatin Condensation ◽  
Light And Electron Microscopy ◽  
Testicular Development ◽  
Tissue Architecture ◽  
Genetic Abnormality ◽  
Human Male ◽  
Testicular Failure

Human male infertility affects ∼5% of men, with one-third suffering from testicular failure, likely the result of an underlying genetic abnormality that disrupts spermatogenesis during development. Mouse models of male infertility such as thePpp1ccknockout mouse display very similar phenotypes to humans with testicular failure. MalePpp1ccmutant mice are sterile due to disruptions in spermatogenesis that begin during prepubertal testicular development, and continue into adulthood, often resulting in loss of germ cells to the point of Sertoli cell-only syndrome. The current study employs light and electron microscopy to identify new morphological abnormalities inPpp1ccmutant seminiferous epithelium. This study reveals that germ cells become delayed in their development around stages VII and VIII of spermatogenesis. Loss of these cells likely results in the reduced numbers of elongating spermatids and spermatozoa previously observed in mutant animals. Interestingly,Ppp1ccmutants also display reduced numbers of spermatogonia compared with their wild-type counterparts. Using electron microscopy, we have shown that junction complexes inPpp1ccmutants are ultrastructurally normal, and therefore do not contribute to the breakdown in tissue architecture seen in mutants. Electron microscopy revealed major acrosomal and chromatin condensation defects inPpp1ccmutants. Our observations are discussed in the context of known molecular changes inPpp1ccmutant testes.

An electron microscope study of the karyotypes of two wolf spiders

1983 ◽  
Vol 25 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Dwayne Wise
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Gradual Increase ◽  
Light And Electron Microscopy ◽  
Genome Length ◽  
Wolf Spiders ◽  
X Chromosomes ◽  
Autosomal Pair

Meiosis in two species of wolf spiders, Lycosa georgicola Walckenaer and Lycosa rabida Walckenaer, has been analyzed by light and electron microscopy. Both karyotypes comprise 13 autosomal pairs + X1X2, all except one pair of which are telocentric. The autosomes show a gradual increase in size ranging from 5.6 to 9.9% of the total genome length. The two X chromosomes of L. rabida are not significantly different in length. In both species, the two X chromosomes are loosely aligned at prophase, but never synapse in the true sense; they do not form synaptonemal complexes. This supports the evidence that X1 and X2 are not homologous. In L. georgicola, one of the X's is associated at prophase with one autosomal pair, but this association does not persist to prometaphase.

Intratesticular distribution of cyritestin, a protein involved in gamete interaction.

1998 ◽  
Vol 201 (6) ◽  
pp. 861-867 ◽  
Author(s):  
A Forsbach ◽  
U A Heinlein
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Germ Cell ◽  
Germ Cells ◽  
Transmembrane Protein ◽  
Differential Staining ◽  
Cell Stage ◽  
Acrosomal Vesicle ◽  
Acrosomal Membrane ◽  
Adam Family

Cyritestin, a member of the ADAM family of proteins, has been shown to be involved in the interaction between sperm and egg during fertilization. The protein is a transmembrane protein associated with the sperm acrosome. In the present study, electron microscopy was used to trace the distribution of the cyritestin molecule in intratesticular germ cells, particularly in haploid round spermatids where the acrosomal structure is differentiating. Our results indicate that cyritestin is transported to the forming acrosomal vesicle through the Golgi apparatus to become part of the acrosomal membrane. Differential staining with antibodies recognizing either the metalloprotease-like domain or the cytoplasmic domain of cyritestin indicates that processing of the molecule leading to the loss of the pro- and metalloproteinase-like domains begins during germ cell stage 6 and is completed before stage 15.

Elastic Scattering in Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 252-253
Author(s):  
J. Langmore ◽  
M. Isaacson ◽  
J. Wall ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Cross Section ◽  
Quantum Noise ◽  
Dark Field ◽  
Elastic Cross Section ◽  
Biological Molecules ◽  
Dark Field Microscopy ◽  
Field Systems ◽  
Effects Of Radiation

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.

Permeability of Endometrial Blood Vessels to Exogenous Horse Radish Peroxidase in Mice. Electron Microscope Study

1973 ◽  
Vol 31 ◽  
pp. 562-563
Author(s):  
M.C. Castillo-Jessen ◽  
A. González-Angulo
Keyword(s):  
Electron Microscopy ◽  
Blood Vessels ◽  
Electron Microscope Study ◽  
Ultrastructural Level ◽  
Low Molecular Weight ◽  
Horse Radish Peroxidase ◽  
Intravascular Injection ◽  
Normal Morphology ◽  
Functional Implications ◽  
Low Molecular Weight Proteins

Information regarding the normal morphology of uterine blood vessels at ultrastructural level in mammals is scarce Electron microscopy studies dealing with endometrial vasculature despite the functional implications due to hormone priming are not available. Light microscopy observations with combined injection of dyes and microradiography along with histochemical studies does not enable us to know the detailed fine structure of the possible various types of blood vessels in this tissue. The present work has been designed to characterize the blood vessels of endometrium of mice as well as the behavior of the endothelium to injection of low molecular weight proteins during the normal estrous cycle in this animal. One hundred and forty female albino mice were sacrificed after intravascular injection of horse radish peroxidase (HRP) at 30 seconds, 5, 15, 30 and 60 minutes.

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