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  • 1
    Electronic Resource
    Electronic Resource
    The Electron Microscopy of Trichomonas muris (1955)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 2 (1955), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. Thin sections of Trichomonas muris, from the caecum of Mesocricetus auratus, were observed with the aid of the electron microscope in order to determine structural details of organelles of this species.The blepharoplast appears to be limited by a membrane. What seem to be basal granules occur in the blepharoplastic area for the axostyle and the lamellae of the undulating membrane and measure approximately 500 Å in diameter.In cross section the anterior flagella and posterior flagellum are composed of eleven fibrils, two centrally and nine peripherally located. Each fibril measures about 380 Å in diameter.The so-called “accessory filament” of the undulating membrane is devoid of any filamentous structure and appears to be composed of two differentiated mesh-work areas. The undulating membrane is composed of a series of lamellae ranging from 300 to 400 Å in thickness. This organelle is attached to the external body surface by fine fibers ranging from 167 to 300 Å in thickness.The costa consists of a series of disks embedded in a matrix. The costa is attached to the internal body surface by what appear to be extensions of the costal disks. These disks are approximately 370 Å in thickness and spaced 490 Å apart.The axostyle is limited by a double, corrugated membrane. The corrugations are about 150 Å in thickness and spaced 110 Å apart. The so-called chromatic ring is composed of a series of rods approximately 640 Å in thickness.The parabasal body consists of a series of filaments approximately 190 Å in thickness.Mitochondria, spheroidal in shape, are limited by a membrane about 180 Å in thickness. The internal structure consists of a varying number of projections which make this organelle appear in section as a series of compartments.Chromatic granules (paracostal, para-axostylar, endo-axostylar and those scattered in the cytoplasm) are irregular in shape and limited by a membrane approximately 200 Å in thickness. These granules typically display a vacuolated internal structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1955.tb02411.x
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  • 2
    Electronic Resource
    Electronic Resource
    A Cytological Study of Chilomonas paramecium with Particular Reference to the So-called Trichocysts (1962)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 9 (1962), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Chilomonas paramecium has been studied by light and electron microscopy with special attention to the so-called trichocysts. The electron miscroscope reveals that the anatomy of these bodies is unlike that of the classical trichocysts of ciliates. Since these structures can be extruded from the body of the organism they have been called ejectisomes. The ejectisomes have a regular geometrical shape and a complex internal structure. They consist of two unequal components which are enclosed by a thin membrane. Morphological polarity is established by an anterior smaller unit and a posterior larger unit. When the ejectisomes are found in the peripheral cytoplasm or in a perivestibular position the smaller unit is always oriented toward the surface. A suggestion is made that the ejectisomes are derived from the vesicular component of the Golgi complex. An interpretation is offered concerning a mechanism by which ejectisomes may be extruded from the body.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1962.tb02640.x
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  • 3
    Electronic Resource
    Electronic Resource
    The Fine Structure of the Heliozoan, Actinosphaerium nucleofilum (1960)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 7 (1960), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Actinosphaerium nucleofilum has been studied by light and electron microscopy. Thin sections of this organism reveal the relatively compact endoplasm to consist of numerous vacuoles and mitochondria. Scattered in the cytoplasm are dense particles, presumably ribonucleoprotein particles, endoplasmic reticulum of the rough variety and a tubular endoplasmic reticulum of the smooth variety. The many nucleido not appear to be randomly scattered in the cytoplasm but rather to be arranged in a circular pattern. Each is bounded by a double membrane envelope. A Golgi complex, consisting of isolated bodies with an ultrastructure similar to that described by others, is usually seen associated with each nucleus.The ectoplasm contains many vacuoles of varying diameter, each of which is limited by a thin membrane; vacuoles containing dense granular material, and mitochondria.The radially arranged axiopodia are extensions of the ectoplasm. The periphery is largely composed of vacuoles, some of which contain dense granules, and mitochondria. The axial rod is birefringent and consists of many fine filaments oriented parallel to the longitudinal axis of the axiopodium. The constituent filaments penetrate deep into the endoplasm where they end in the vicinity of nuclei. The fibrillar component of the axiopodia may represent contractile units.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1960.tb00729.x
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  • 4
    Electronic Resource
    Electronic Resource
    The Ultrastructure of Tritrichomonas with Special Reference to the Blepharoplast Complex (1961)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 8 (1961), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Electron micrographs of sections through the blepharoplast complex reveal it to be composed of four kineto-somes. In many of the sections the kinetosomes contain dense particles approximately 180-200 A in diameter. The costa is a striated fiber which extends posteriorly almost the entire length of the body. Its slender proximal portion appears to be attached to the base of the kinetosome of the recurrent flagellum. The parabolas fiber is similarly constructed, but is more slender than the costa. It is attached to the base of the kinetosome of an interiorly directed flagellum and subsequently proceeds posteriorly to the level of the nucleus. The costa and parabasal fiber probably serve as anchoring or supportive structures. The size of the costa may reflect its role as a supporting structure for the most highly differentiated locomotors organelle, the undulating membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1961.tb01185.x
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  • 5
    Electronic Resource
    Electronic Resource
    Studies on the Fine Structure of a Gregarine Parasitic in the Gut of the Grasshopper, melanoplus differentialis (1959)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 6 (1959), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SYNOPSIS. Materials within the endoplasm of both the protomerite and deutomerite may be displaced and stratified by ultracentrifugation. Animals are not killed by this treatment, and in time a redistribution of stratified materials may occur. The electron microscope reveals numerous ultramicroscopic folds in the surface envelope which is composed of 3 membranes; the outer and middle cover the surface of the folds while the inner one continues as a smooth membrane over the ectoplasm. The contact surfaces of animals in syzygy do not show the small folds to be interlocked; instead, they are in fold-to-fold contact. Numerous relatively dense bodies which appear to be filamentous are sometimes observed immediately underneath or within the middle or inner membrane. Within the ectoplasm is an ultramicroscopic net-like fibrillar structure much denser than the surrounding cytoplasm. This system of fibrils is composed of anastomosing elements varying from ∼ 50 to 200 Å in diameter. Certain of the larger fibrils are directly attached to the surface envelope at positions between the folds. A second filamentous structure within the ectoplasm appears to be tubular. Elements of this system also appear to join and penetrate the surface envelope by means of pores.A large amount of gelatinous secretion forms at the surface of the sporont; as it glides forward a trail of mucous is left behind. The actual mechanism involved in the gliding movement was unobserved, but evidence is lacking to support the view that the gliding movement is engendered by posteriorly directed “jets” of mucus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1959.tb03940.x
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  • 6
    Electronic Resource
    Electronic Resource
    Hormonal modulation of gap junctions in rat ovarian follicles (1981)
    Springer
    Cell & tissue research 214 (1981), S. 181-193 
    Details
    ISSN: 1432-0878
    Keywords: Gap junctions ; Hormonal modulation ; Rat ovary ; Granulosa cells ; Thecal cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Homocellular gap junctions between granulosa cells and between theca interna cells, and heterocellular gap junctions between granulosa cells and oocytes persist in rat ovarian follicles for as long as 90 days following hypophysectomy. Gonadotrophic and/or steroid hormones are therefore not required for the maintenance of gap junctions between these cells during early follicular growth. However, replacement therapy with estrogen and human chorionic gonadotrophin results in amplification of gap junctions in granulosa and theca interna cells respectively. Within 24 h following hormonal stimulation, growth of gap junctions is characterized by the appearance of formation plaques as observed in freeze-fracture replicas and by the association of microfilamentous material located subadjacent to gap junction membrane observable in thin-sectioned cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235155
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  • 7
    Electronic Resource
    Electronic Resource
    A cytological study of the ovary of Rhodnius prolixus. I. The ontogeny of the follicular epithelium (1972)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 136 (1972), S. 459-493 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The relatively undifferentiated cells comprising the prefollicular epithelium of the fourth and fifth instar of the reduvid bug Rhodninus prolixus are flattened and contain the regularly occurring organelles, lipid droplets, and aggregates of glycogen-like particles. These cells transform into the adult prefollicular tissue.During vitellogenesis there is a gradual shortening of the cells of the follicular epithelium and an increase in the size of the intercellular space between them and between follicle cells and oocyte. The follicle cells are binucleate, contain numerous microtubules, rough endoplasmic reticulum, many free and aggregate ribosomes, and Golgi complexes. They are associated with each other by gap junctions. Only the follicle cells on the lateral aspects of the oocyte exhibit the development of large extracellular spaces while those at the apical end, that produces the cap, remain tall and closely apposed to each other during vitellogenesis. The normal morphology of the follicle cells over various areas of the oocyte suggests that shape and/or volume changes of these cell may be important in regulating the access of yolk proteins to the colemma.Subsequent to vitellogenesis the follicle cells become cuboidal and once again become closely apposed to each other. They contain much rough endoplasmic reticulum and produce the secondary coat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051360405
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  • 8
    Electronic Resource
    Electronic Resource
    A correlative microscopical analysis of differentiating ovarian follicles of mammalsThis investigation was supported by Grants (HD 06822; HD 06645) from the National Institutes of Health and the United States Public Health Service. (1978)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 156 (1978), S. 339-366 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mammalian ovary has been studied by optical microscopy and by scanning and transmission electron microscopy with the purpose of presenting an integrated view of the differentiating mammalian follicle. During follicular development, changes in the granulosa cells are particularly noteworthy and include dramatic modifications in cell shape coincident with antrum formation. The cytoplasmic processes of those granulosa cells immediately surrounding the oocyte, as well as the more peripheral granulosa cells comprising a second and third layer, traverse the zona pellucida, infrequently interdigitate with the microvilli of the egg, and make both desmosomal and gap junction contacts with the oocyte. The zona pellucida is thus distinguished by numerous fenestrations of varying diameters. The membrana limitans (basal lamina) is a bipartite structure composed of (a) a homogeneous stratum upon which the peripheral layer of granulosa cells rests, and (b) an outer region of collagen-like fibers. The specific advantages and limitations of the different methodologies utilized to study folliculo-genesis are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051560303
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  • 9
    Electronic Resource
    Electronic Resource
    Oocyte-follicle cell differentiation in two species of Amphineurans (Mollusca), Mopalia mucosa and Chaetopleura apiculataThis investigation was supported by grant GM-08776 from the National Institutes of Health, United States Public Health Service. The author wishes to thank Mrs. Gloria Lee and Mr. and Mrs. L. Musante for their able technical assistance. (1969)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 129 (1969), S. 89-125 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Differentiating oocytes and associated follicle cells of two species of amphineurans (Mollusca) Mopalia muscosa and Chaetopleura apiculata have been studied by techniques of light and electron microscopy. In addition to the regularly occurring organelles, the ooplasm of young oocytes contains large, randomly situated, basophilic regions. These regions are not demonstrable in mature eggs.As oocytes differentiate, lipid, pigment and protein-carbohydrate yolk bodies accumulate within the ooplasm. Concomitant with the appearance of pigment and the protein carbohydrate containing yolk bodies, the saccules of the Golgi complex become filled with a dense material. Associated with the Golgi complex are cisternae of the rough endoplasmic reticulum which are filled with an electron opaque substance which is thought to be composed of protein synthesized by this organelle. That portion of the cisternae of the endoplasmic reticulum facing the Golgi complex shows evaginations. These evaginations are thought to finalize into protein containing vesicles that subsequently fuse with the Golgi complex. Thus, the Golgi complex in these oocytes might serve as a center for packaging and concentrating the protein used in the construction of the protein containing pigment or protein-carbohydrate yolk bodies. The suggestion is made that the Golgi complex may also synthesize the carbohydrate portion of the formentioned yolk bodies.In an adnuclear position in young oocytes are some acid mucopolysaccharide containing vacuolar bodies. In mature eggs, these structures are found within the peripheral ooplasm and we have referred to them as cortical granules. There is no alteration of these cortical granules during sperm activation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051290107
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  • 10
    Electronic Resource
    Electronic Resource
    A study of oogenesis and early embryogenesis in the rabbit, Oryctolagus cuniculus, with special reference to the structural changes of mitochondriaThis investigation was supported by a grant GM 08776 from the National Institutes of Health, United States Public Health Service. The authors wish to thank Mrs. Gloria S. Lee and Mr. and Mrs. L. Musante for their technical assistance. (1970)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 130 (1970), S. 67-91 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structural changes of mitochondria that occur during oogenesis and early embryogenesis in the rabbit have been examined with the electron microscope. Mitochondria of oogonia are both elongate and oval and contain a variable number of cristae which may or may not traverse the longitudinal axis of the organelle. When oogonia differentiate into oocytes, mitochondria become spheroidal and their cristae are sparse when compared with those found in the ellipsoidal organelles of concomitantly maturing follicle cells. As differentiation proceeds, the cristae of the mitochondria display varied configurations. For example, many display an arch-like arrangement in several regions of the organelle whereas others contain a pair of concentric membranes closely associated with limiting membrane of the mitochondrion.Mitochondria of stages from the fertilized egg to the morula possess the same internal structure as those of young oocytes. As the morula differentiates into a blastocyst there is a gradual increase in the size of the mitochondria and an increase in the number of cristae. We believe that the number and modifications of cristae indicate stages of mitochondriogenesis and the level of enzymatic activity in which this organelle is engaged during oogenesis and early embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051300108
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