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R G Kessel

Publications and source records attributed to R G Kessel.

At least 19 recordsLinked to original sources
PubMed1992

Effects of acrylamide on germinal vesicle migration and dissolution in oocytes of the frog, Rana pipiens.

We have demonstrated that when Rana oocytes are treated with 10 mM acrylamide, germinal vesicle migration (GVM) is promoted while meiosis reinitiation by progesterone is inhibited. A number of other specific alterations result from the acrylamide treatment: (i) A dense band of fibrillar material appears adjacent to the oolemma in acrylamide-treated oocytes. Furthermore, (ii) the fibrillar material reacts with an intermediate filament antibody using immunogold techniques applied to transmission electron microscopy. Moreover, (iii) acrylamide inhibits progestogen-induced annulate lamellae breakdown. In addition, (iv) the cortical mitochondria-rich layer appears to be thickened by acrylamide, which also (v) affects oocyte microvillar retraction and organization. Finally, (vi) electrophysiological measurement of membrane voltage indicates that acrylamide does not significantly affect cell viability during the incubation period used in this study. In summary, acrylamide exerts profound effects on the physiological event of GVM, and these are consistent with the hypothesis that changes in the cytoskeleton are a contributing factor in meiosis reinitiation.

Acrylamide↗
PubMed1990

Freeze fracture and scanning electron microscope studies on the nuclear envelope and perinuclear cytomembranes (parabasal apparatus) in the protozoan, Lophomonas blattarum.

Phase contrast, scanning electron microscope (SEM), and freeze fracture studies on the parasitic flagellate, Lophomonas blattarum, have demonstrated that the endomembrane system (parabasal apparatus) is highly ordered, restricted in position to a perinuclear zone at the anterior end of the organism, and is supported in this localized cytoplasmic region by overlapping sheets or plates of microtubules, previously called the calyx and axial filament, which may participate in supporting the nucleus-endomembrane system in a restricted region of the cell. Light microscope observations, SEM and freeze fracture data provide support to previous views that the rough- and smooth-surfaced endoplasmic reticulum are interconnected and attached to the outer layer of the nuclear envelope. The continuity of these membrane systems provides an orderly and restricted packing in the perinuclear cytoplasm since other areas of the cell may become filled with yeast. These flagellates are especially adept at phagocytosis of entire yeast. In yeast-laden cells, the flagella-nucleus-parabasal body-calyx-axial filament complex may separate from the remainder of the cell and assume a motile existence for a time. The significance of the described relationships, in addition to providing efficiency in endomembrane localization, may also reflect synthesis of enzymes and proteins by the RER and packaging in the SER, both of which are continuous. Granules characteristic of glycogen are concentrated around the SER which may be involved in glycogen metabolism. Although critical information is lacking, the endomembrane system may also be involved in the synthesis and morphogenesis of lysosomes, and perhaps peroxisomes. Lophomonas thus amplifies a highly ordered spatial relationship between the nuclear envelope and the ER.

Animals↗
PubMed1989

The annulate lamellae--from obscurity to spotlight.

This review aims to provide a comprehensive and in-depth survey of a cell organelle, the annulate lamellae, that is widely distributed and especially prevalent in both female and male sex cells as well as tumor and cancer cells. The organelle is also present in many somatic cells and plant cells. Emphasis is placed on the contributions that electron microscopy and associated experimental approaches have made in providing information about the distribution, ultrastructure, morphogenesis and relationships of annulate lamellae to other cellular organelles, especially the nuclear envelope and endoplasmic reticulum, as well as cell product. An increasing number of experimental manipulations have recently been shown to alter, either increase or decrease, the amount of annulate lamellae and these studies are explored in depth. Information about the origin and morphogenesis of annulate lamellae in different cells is summarized and extensive coverage is given to several hypotheses about possible annulate lamellae function. A detailed bibliography provides a thorough compilation of research dealing with annulate lamellae. A major goal of this extensive review is to generate increased awareness of, and interest in, this cell organelle for students and investigators of the cell who, by bringing current techniques in cell and molecular biology to bear, might focus and intensify studies on the function of an organelle whose precise role in the cell is presently enigmatic.

Animals↗
PubMed1988

Intercellular junctions in the follicular envelope of the teleost, Brachydanio rerio.

The nature and distribution of intercellular junctions in the outer ovarian epithelium (serosa, mesothelium), endothelium, and follicle cells of the teleost oocyte-follicle complex were investigated by freeze-fracture electron microscopy. Tight-junctions were common between outer squamous epithelial cells, sometimes closely associated with intercalated foci of communicating junctions. The tight junctions consisted of one to several sealing strands which possessed focal discontinuities. In addition, the strands existed as loops or as short, free-ending elements; a condition that could indicate lability in their assembly or disassembly. The presence of free-ending strands could also mean that the structure serves for attachment as well as involved in the formation of occluding zonules. The free ends of some bars comprising the tight junctional strands are enlarged slightly. In outer ovarian epithelial or serosal cells, as is the case for mammalian mesothelium described by others, clusters of particles comprising communicating (gap) junctions are often intercalated within or are located in close proximity to tight junctional strands. In freeze-cleaved replicas, the outer squamous epithelial (serosal) cells contained a multitude of micropinocytotic pits (caveolae) and vesicles. Capillary endothelium also contains tight junctional components which are often closely associated with communicating junctions. Tight junctions also exist between follicle cells, but their structure changes during oocyte growth. Communicating junctions between follicle cells tend to be focal in distribution and not closely associated with tight junctions.

Animals↗
PubMed1986

Is the nuclear envelope a 'generator' of membrane? Developmental sequences in cytomembrane elaboration.

Early diplotene oocytes from Necturus maculosus ranging from approximately 0.2 to 0.5 mm in diameter were examined by electron microscopy. In the smallest oocytes of this range, the cytoplasm is largely devoid of membranes, but contains primarily ribosomes and mitochondria. In slightly larger oocytes, smooth-surfaced cytomembranes first appear in the perinuclear cytoplasm. At this time, the outer layer of the germinal vesicle nuclear envelope (GVNE) shows frequent connections with long membranous lamellae that extend for considerable, but variable distances into the juxtanuclear ooplasm. The number of smooth membranous lamellae increases tremendously as the oocytes increase in diameter. In such oocytes as well, frequent continuities are observed between the outer membrane of the GVNE and many of the cytoplasmic membranes. Eventually, as the ooplasm becomes populated with extensive numbers of membranous lamellae, instances of continuity between the membranous lamellae and nuclear envelope now become sparse and eventually non-existent. The frequent connections observed between membranous lamellae and the outer membrane of the GVNE during a circumscribed interval of diplotene strongly implicate the GVNE in the generation of extensive amounts of cytoplasmic membrane. The ooplasm of larger oocytes in the size range indicated contain numerous Golgi complexes and large quantities of annulate lamellae most of which are positioned in the peripheral or subcortical ooplasm, as well as extensive quantities of smooth membranes of the endoplasmic reticulum and lipid droplets.

Animals↗
PubMed1985

Filipin-sterol complexes in the plasma membrane of zebrafish spermatozoa.

The presence and distribution of filipin-sterol complexes in the plasma membrane of zebrafish (Brachydanio rerio) sperm was investigated. The zebrafish sperm plasma membrane, treated with freeze-fracture techniques, is seen to contain a multitude of intramembranous particles that, in a specific region of the posterior part of the sperm head, are organized into unusual particle arrays that appear as simple hexagons or parallelograms. The polyene antibiotic filipin forms complexes with 3-beta-OH sterols to produce characteristic protrusions and pits in membranes that are readily observable in freeze-fracture replicas. Numerous filipin-sterol complexes were found to populate the sperm plasma membrane, and the complexes exhibited variability in their distribution in different sperm. This appears to be the first illustrated example of an acrosomeless sperm that exhibits a high concentration of filipin-sterol complexes. In contrast, the unique grating formed by the intramembranous particles as well as variable amounts of membrane surrounding the unusual particle arrays were always free of the filipin-sterol complexes. Thus, while cholesterol appears to be present in the plasma membrane of the zebrafish sperm, it is not apparent in the highly differentiated region of the membrane based on the observed distribution of the filipin-sterol complexes.

Animals↗
PubMed1985

The presence and distribution of gap junctions in the oocyte-follicle cell complex of the zebrafish, Brachydanio rerio.

Membranes of teleost female gametes and investing layer of follicle cells characteristically exhibit a prolonged, close spatial relationship. This relationship is manifested, in part, by numerous folds of the plasma membrane of both oocyte and follicle cells that extend through channels called pore canals within a thick, laminated extracellular coat, the vitelline membrane. During oogenesis the folded oocyte processes, or microvilli, increase in number and length, but decrease in width. Follicle cell processes are frequently wider and less numerous than oocyte microvilli, but do not usually touch the unfolded portion of the oocyte surface. Throughout development, distal portions of oocyte microvilli contact either the proximal portion of follicle cell processes or unfolded parts of the follicle cell plasma membrane where many membranous specializations characteristic of gap junctions are present, especially during intermediate and later stages of oogenesis. Freeze-fracture replicas of the oocyte-follicle complexes revealed numerous localized aggregations of discrete intramembranous particles approximately 9-15 nm diameter that are characteristic of gap junctions. Gap junctions were located in the region of contact between the terminals of oocyte microvilli in relation to the different areas of the follicle cell plasma membrane. In ultrathin sections, the apposed plasma membranes of oocyte microvilli and follicle cells, in places, take the form of a seven-layered membrane approximately 18 nm thick which is bisected by a 2 nm gap that appears somewhat electron dense due to uranyl acetate stain. The location of gap junctions in the zebrafish oocyte-follicle is different from the situation in mammals where gap junctions are associated with cumulus cell processes as they make contact with the oocyte. The entire oocyte-follicle cell complex in the zebrafish contains the structural pathways for the transfer of small molecules between these cells.

Age Factors↗
PubMed1984

Effects of prolonged antitubulin culture on the ultrastructure of anterior limb bud cells of the chick embryo.

The anterior limb bud mesenchyme cells of stage 24 chick embryos were dissociated by trypsinization followed by gentle pipetting, and placed in a tissue culture medium of F12 containing 10% fetal calf serum and antibiotics. As the cells became nearly confluent, some of them were exposed to colchicine or vinblastine sulfate for durations as long as 48 hr. The control and antitubulin-treated cells were processed for transmission electron microscopy and the ultrastructure of the cells was compared. Annulate lamellae (AL) were observed in small amounts in both control and antitubulin-treated cells. The amount of AL did not markedly differ in the control versus antitubulin-treated cells. Furthermore, few multinucleated cells were observed in antitubulin-treated cultures. These results indicate that prolonged culture of cells in antitubulins need not, in itself, lead to a condition of enhanced AL development as reported in several other studies using various cell types.

Animals↗
PubMed1984

Effects of prolonged antitubulin culture on annulate lamellae in mouse alpha L929 fibroblasts.

The fine structure of alpha L929 fibroblasts cultured in colchicine or vinblastine sulfate for periods as long as 48 hr was compared to control cells not exposed to antitubulins . In response to prolonged antitubulin culture, several changes in cell ultrastructure were noted: Control fibroblasts contain cytoplasmic annulate lamellae (AL), but prolonged exposure to either vinblastine sulfate or colchicine results in enhanced development of AL. Single pore complexes are present in the rough-surfaced endoplasmic reticulum (rER) in both control and antitubulin-treated cells, but stacked porous cytomembranes also occur under both conditions. Polyribosomes often are closely associated or continuous with the pore complexes. Many antitubulin-treated cells become multinucleate. Some nuclei in both control and antitubulin-treated cells contain large and multiple nucleoli. The large and multiple nucleoli are either attached directly to the inner membrane of the nuclear envelope or to infoldings of the nuclear envelope. Antitubulin-treated cells, after 48-hr exposure, appear also to contain enhanced quantities of smooth-surfaced endoplasmic reticulum (sER) and cytoplasmic filaments (and in some cells, lysosomes and rER as well) when compared to untreated cells. In both control and colchicine-treated cells, AL can exhibit continuity with either rER or sER. Further, all three membrane systems may at times be continuous, but the quantity of these membranes appears to be greater in colchicine-treated cells than in control cells. The results are discussed with respect to possible functional significance.

Animals↗
PubMed1984

Relationships between annulate lamellae and filament bundles in oocytes of the zebrafish, Brachydanio rerio.

Bundles of filaments have been observed in the vitellogenic oocyte of the zebrafish, Brachydanio rerio; and these filaments illustrate a close spatial and structural relationship to annulate lamellae. The filaments range from 6-8 nm in diameter, and the annulate lamellae may cap both rounded ends of the bundle as well as extend parallel to the surface of the filament bundles. The ends of the filaments can be observed to exhibit an apparent termination in close relation to pore margins of the annulate lamellae, the membrane of the interpore regions of the annulate lamellae, as well as many nearby polyribosomes. The possible functional significance of this unique relationship is discussed in reference to a recent hypothesis regarding the function of annulate lamellae.

Animals↗
PubMed1984

Intracisternal tubules and intramitochondrial filaments in cells of a snail, Limnaea.

Epithelial and peritubular cells associated with the reproductive tract of the snail, Limnaea stagnalis, contain an extensive system of endoplasmic reticulum that is often dilated with many closely packed intracisternal tubules. The intracisternal tubules are approximately 24-28 nm in diameter and they are often hexagonally packed. They have a two-layered wall, possess fine interconnections, and extend linearly for considerable distances, but angular bends in the tubules also occur. Mitochondria in the peritubular cells contain solid, filamentous structures 9-12 nm in diameter and triangular-shaped structures when sectioned in the mitochondrial matrix.

Animals↗
PubMed1983

Intranuclear membranes (vesicles, lamellae, annulate lamellae) in oocytes of the ascidian, Styela partita.

Transmission electron microscope studies on developing oocytes of Styela partita that were preserved with a primary fixative of buffered glutaraldehyde and a secondary fixative of buffered osmium tetroxide have dealt with the origin, distribution, and associations of intranuclear annulate lamellae in both previtellogenic and vitellogenic oocytes. These studies (1) substantiate that, developmentally, intranuclear vesicles appear to precede differentiated intranuclear annulate lamellae although intranuclear vesicles and intranuclear annulate lamellae may coexist in the same nucleus (germinal vesicle), (2) substantiate an earlier demonstration that the inner membrane of the nuclear envelope forms blebs which could, after detachment, become intranuclear vesicles, (3) confirm that the pore-associated material of the pores in intranuclear annulate lamellae appears to be structurally identical to that of the pores in the nuclear envelope, (4) demonstrate that at certain times during oogenesis electron-dense material inside the nucleus, thought to represent nucleolar-derived material, is continuous with the pore-associated material of pores in both intranuclear annulate lamellae and the nuclear envelope, (5) propose a function for intranuclear annulate lamellae that considers the pores to play a role in processing or assembling various RNA's and proteins to become cytoplasmic polyribosomes as has recently been suggested also for the pores in the nuclear envelope as well as pores in cytoplasmic or extranuclear annulate lamellae, and (6) provide additional evidence that intranuclear annulate lamellae are not remnants of the nuclear envelope persisting after mitosis as has been described to be the case in certain other cells.

Animals↗
PubMed1981

Alteration of annulate lamellae in the in vitro progesterone-treated, full-grown Rana pipiens oocyte.

In full-grown but immature Rana pipiens ovarian oocytes, stacks of annulate lamellae are preferentially localized in the ooplasm between the germinal vesicle and the animal pole.l Furthermore, the largest stacks of these porous cytomembranes tend to be localized deeper in the ooplasm in proximity to the germinal vesicle, while smaller, but variable-sized stacks of annulate lamellae area found closer to the oolemma of the animal pole. Manually defolliculated, full-grown oocytes were cultured in progesterone for periods of 1, 3, 5, 6, 9, 12, 16, 18, and 22 hours at 18 degrees C. Annulate lamellae were observed in the animal pole ooplasm after 1, 3, 5, 6, and 9 hours of in vitro culture in progesterone at 18 degrees C. In contrast, annulate lamellae were not observed in fully grown oocytes cultured in the progesterone for 12, 16, 18, or 22 hours at 18 degrees C. Rather, many localized areas in the animal pole ooplasm wer observed that contained large numbers of closely packed vesicles of different size. The largest clusters of vesicles were present in the ooplasm near the germinal vesicle. Progressing toward the oolemma of the animal pole, the vesicular clusters appeared to become smaller in area. These clusters of vesicles were not observed in either untreated control oocytes at 3-22 hours of culture, or in those treated with progesterone for 1, 3, 5, 6, or 9 hours. The results suggest that after the appropriate maturation-inducing treatment with progesterone, annulate lamellae lose their integrity, probably by a process of vesiculation. This represents one of the first morphological changes which occurs during the induction of meiotic maturation. The alteration of annulate lamellae observed in the progesterone-treated oocytes occurs prior to the complete germinal vesicle breakdown, for under the experimental conditions described, the germinal vesicle nuclear envelope did not completely break down until between 18 and 22 hours of culture in progesterone.

Animals↗