Structure and development of the spermatozoon of the parasitic nematode, Nematospiroides dubius

Parasitology ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 179-192 ◽  
Author(s):  
E. J. Wright ◽  
R. I. Sommerville
Keyword(s):  
Electron Microscopy ◽  
Germ Cells ◽  
Parasitic Nematode ◽  
Head Shape ◽  
Profound Change ◽  
Arrow Head ◽  
Golgi Bodies ◽  
Membrane Bound ◽  
Nematospiroides Dubius

Spermatogenesis and sperm maturation in Nematospiroides dubius were studied using electron microscopy. The testis is telegonic and germ cells in the zones of mitosis, growth and meiosis are connected by a central anucleate mass of cytoplasm, the rachis. The early part of spermatogenesis is dominated by the synthesis and growth of membrane-bound vesicles called membranous organelles, which originate from RER-associated Golgi bodies. Following meiosis the spermatids separate from the rachis and their chroinatin, which is no longer bounded by a nuclear envelope, condenses into an arrow-head shape and is extruded to form a tail-like structure. After insemination spermatozoa undergo a profound change called activation. The cytoplasmic region which was previously long and cylindrical becomes spherical and the membranous organelles which lined its perimeter fuse with the plasma membrane and become confined to the posterior hemisphere of the sperm, close to the nuclear tail. The anterior half of the sperm is devoid of organelles but contains many filaments organized into clumps and chains; this region being responsible for amoeboid locomotion of the sperm.

Cytology of mucilage production in the seed coat of Candle canola (Brassica campestris)

1981 ◽  
Vol 59 (3) ◽  
pp. 292-300 ◽  
Author(s):  
L. Van Caeseele ◽  
J. T. Mills ◽  
M. Sumner ◽  
R. Gillespie
Keyword(s):  
Electron Microscopy ◽  
Seed Coat ◽  
Brassica Campestris ◽  
Light And Electron Microscopy ◽  
Epidermal Cells ◽  
Starch Grains ◽  
Golgi Bodies ◽  
Tangential Wall ◽  
Membrane Bound

The development of mucilage in the epidermal cells of canola seeds (Brassica campestris L. cv. Candle) was studied with light and electron microscopy from 5 days after pollination to maturity. During the first 17 days starch was deposited in amyloplasts. At or near the 17th day mucilage appeared between the plasmalemma and the outer tangential wall of the epidermal cells. As the volume of mucilage increased, starch grains disappeared and were totally absent by 25 days. Membrane-bound structures and Golgi bodies were visible within the cytoplasm adjacent to the site of mucilage deposition. At maturity the seed epidermal cells were totally devoid of cytoplasm and engorged with mucilage.

The structure and development of the spermatozoon of Dipetalonema viteae (Nematoda: Filarioidea)

Parasitology ◽  
1973 ◽  
Vol 66 (3) ◽  
pp. 447-463 ◽  
Author(s):  
Diane J. McLaren
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Germ Cells ◽  
Reproductive Tract ◽  
Mature Spermatozoon ◽  
Male And Female ◽  
Golgi Bodies ◽  
Male Gametes ◽  
Mammalian Spermatozoon ◽  
Dipetalonema Viteae

The structure and development of the spermatozoon of Dipetalonema viteae has been studied by means of electron microscopy. Spermatogonia are developed from a syncytium in the terminal region of the reproductive tract. The syncytium grows along the length of the testis as an anucleate rachis, carrying with it the developing germ cells. The gametes become detached from the rachis when they have become secondary spermatocytes. The chromosomes which appear in the primary spermatocytes at the onset of meiosis persist throughout all subsequent stages of development. The nucleus is not reconstructed. Cytophores are produced by the spermatids at the end of the second meiotic division. The spermatid is an elongated cell, but the mature spermatozoon, within the male tract, is amoeboid. There are only minor differences between the sperm found in the male and female tracts. The male gametes contain complex membraneous organelles which are developed from the Golgi bodies and endoplasmic reticulum of the primary spermatocytes. These organelles are suggested to have similar origins and functions to the acrosome of the typical mammalian spermatozoon.

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.

Golgi Bodies in the Male Germ-Cells of Vaginula maculata

Nature ◽  
1953 ◽  
Vol 172 (4380) ◽  
pp. 690-690 ◽  
Author(s):  
JOHN R. BAKER
Keyword(s):  
Germ Cells ◽  
Male Germ Cells ◽  
Golgi Bodies

The Tegument and Associated Structures of Fasciola Hepatica

1963 ◽  
Vol s3-104 (68) ◽  
pp. 505-512
Author(s):  
L. T. THREADGOLD
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Light Microscopy ◽  
Fasciola Hepatica ◽  
Golgi Bodies ◽  
New Knowledge ◽  
Pinocytotic Vesicles ◽  
The Individual ◽  
And Function ◽  
Internal Level

The cuticle of light microscopy is shown by electron microscopy to be a surface layer of protoplasm which is an extension of areas of nucleated protoplasm lying deep in the parenchyma. The cuticle therefore exists at two levels. The external level is syncytial, consisting of plateaux separated by branching valleys. This level contains apical pinocytotic vesicles, numerous mitochondria, endoplasmic membranes, large basal and other vacuoles, and dense spines. Tube-like evaginations from the base of the external level connect it to the individual areas of flask-shaped protoplasm which compose the internal level. Each of these areas of protoplasm contains a nucleus, great numbers of mitochondria, some vacuoles and diffuse inclusions, and the Golgi bodies. The histochemistry and function of the cuticle is discussed in the light of this new knowledge of cuticular ultrastructure, and a comparison is made between the cuticle of Cestoda and Trematoda.

Comparative morpho-anatomical studies of the female gonoduct within the Pratylenchidae (Nematoda: Tylenchina)

Nematology ◽  
2003 ◽  
Vol 5 (2) ◽  
pp. 293-306 ◽  
Author(s):  
Gaëtan Borgonie ◽  
Wim Bert ◽  
Ruben Van Gansbeke ◽  
Etienne Geraert ◽  
Myriam Claeys
Keyword(s):  
Electron Microscopy ◽  
Germ Cells ◽  
The Other ◽  
Radopholus Similis ◽  
Cell Extension ◽  
Anatomical Studies ◽  
Transmission Electron ◽  
Wall Cell ◽  
Ovarian Wall ◽  
Nacobbus Aberrans

AbstractThe cellular morphology of the gonoduct of six Pratylenchus species, three Pratylenchoides species, Radopholus similis, Zygotylenchus guevarai, Hirschmanniella loofi and Nacobbus aberrans was revealed by dissection and light microscopy. Except for Nacobbus aberrans, all studied species show an overall similarity in gonoduct construction, i.e., an ovary often ending with a ring of cells, an oviduct formed from two rows of four cells and a 12-celled spermatheca followed by a tricolumella containing 16-24 cells. Pratylenchoides magnicauda and Z. guevarai did not diverge from the other Pratylenchidae in this respect, although their gonoduct differs from that of Amplimerlinius and Meloidogyne, both formerly postulated as related genera. The spermatheca structure observed in N. aberrans has not been reported elsewhere in the Nematoda, although the uterus is similar to that reported within the Heteroderinae and Meloidogyninae and the uterus comprises more than 300 cells, enlarging from a tricolumella to a polycolumella. Transmission electron microscopy of Z. guevarai revealed details of the cytoplasmatic contact between epithelial cells and the germ cells; a finger-like ovarian wall cell extension was found penetrating the oocyte. The oviduct lacks a preformed lumen and comprises eight cells with highly plicated cell membranes. The spermatheca is constructed from flattened wall cells and is followed by columnar uterus cells where evidence of eggshell formation was demonstrated.

scholarly journals Infection With a Novel Rickettsiella Species in Emperor Scorpions (Pandinus imperator)

2020 ◽  
Vol 57 (6) ◽  
pp. 858-870
Author(s):  
Sushan Han ◽  
Aníbal G. Armién ◽  
Janet E. Hill ◽  
Champika Fernando ◽  
Dan S. Bradway ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rapid Progression ◽  
Protein Coding ◽  
Hematopoietic Organ ◽  
Transmission Electron ◽  
History Of ◽  
Gross Lesions ◽  
Membrane Bound ◽  
Methenamine Silver

Rickettsiella infection was diagnosed in 4 adult emperor scorpions ( Pandinus imperator) from 2 different collections over a 3-year period. One case had a 2-day history of weakness, failure to lift the tail, or respond to stimulation, with rapid progression to death. The other 3 cases were found dead. There were no gross lesions, but histologically the hemolymphatic vasculature and sinuses, presumed hematopoietic organ, heart, midgut and midgut diverticula, nerves, and skeletal muscle were infiltrated with phagocytic and granular hemocytes with necrosis. Phagocytic hemocytes contained abundant intracellular microorganisms that were Fite’s acid-fast-positive, Macchiavello-positive, variably gram-positive or gram-negative, and Grocott’s methenamine silver-negative. By transmission electron microscopy, hemocytes contained numerous phagocytic vacuoles with small dense bacterial forms (mean 0.603 × 0.163 μm) interspersed with large bacterial forms (mean 1.265 × 0.505 μm) and few intermediary forms with electron-dense nucleoids and membrane-bound crystalline arrays (average 4.72 μm). Transmission electron microscopy findings were consistent with bacteria of the family Coxiellaceae. Based on sequencing the 16S ribosomal RNA gene, the identity was confirmed as Rickettsiella, and phylogenetic analysis of protein-coding genes gidA, rspA, and sucB genes suggested the emperor scorpion pathogen as a new species. This study identifies a novel Rickettsiella causing infection in emperor scorpions and characterizes the unique pathological findings of this disease. We suggest this organism be provisionally named Rickettsiella scorpionisepticum.

Ultrastructure of cuticle formation in a parasitic nematode, Nematospiroides dubius

1970 ◽  
Vol 104 (2) ◽  
pp. 193-204 ◽  
Author(s):  
Thomas P. Bonner ◽  
Max G. Menefee ◽  
Frank J. Etges
Keyword(s):  
Parasitic Nematode ◽  
Cuticle Formation ◽  
Nematospiroides Dubius

Primary culture of porcine PGCs requires LIF and porcine membrane-bound stem cell factor

Zygote ◽  
1998 ◽  
Vol 6 (3) ◽  
pp. 271-275 ◽  
Author(s):  
Gabriela Durcova-Hills ◽  
Katja Prelle ◽  
Sigrid Müller ◽  
Miodrag Stojkovic ◽  
Jan Motlik ◽  
...  
Keyword(s):  
Stem Cell ◽  
Primary Culture ◽  
Germ Cells ◽  
Stem Cell Factor ◽  
Primordial Germ Cells ◽  
Embryonic Stem ◽  
Leukaemia Inhibitory Factor ◽  
Feeder Cells ◽  
Membrane Bound

We studied the effect of murine leukaemia inhibitory factor (LIF), human basic fibroblast growth factor (bFGF) and porcine stem cell factor (SCF) on the survival and/or proliferation of porcine primordial germ cells (PGCs) obtained from 27-day-old embryos in vitro. PGCs were cultured in embryonic stem cell (ESC) medium supplemented with or without either LIF (1000 IU/ml) alone or LIF together with bFGF (10 ng/ml). They were seeded on mitotically inactivated feeder cells, either STO or transfected STO cells (STO#8), expressing the membrane-bound form of porcine SCF. PGCs were identified by their alkaline phosphatase (AP) activity and counted after 1, 3 and 5 days in culture. After 1 day of culture, PGCs cultured on STO#8 cells showed significantly higher survival than PGCs cultured on STO cells (p < 0.05). The combined effect of SCF and LIF caused a significant increase in PGC number by day 3 of culture when PGCs were cultured on either STO cells (p < 0.01) or STO#8 (p < 0.001). When SCF and LIF were used together with bFGF no increase in the PGC number was observed. Our results suggest that the membrane-bound form of porcine SCF plays a pivotal role in the primary culture of porcine PGCs and that bFGF is not required in vitro.

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