Showing papers on "Protoplast published in 1970"

Virus uptake, cell wall regeneration, and virus multiplication in isolated plant protoplasts.

Abstract: Publisher Summary The ready availability of enzymically isolated protoplasts has greatly stimulated work in relation to studies on the entry of macromolecules into protoplasts, on cell wall regeneration, and on the ability of such regenerated isolated protoplasts to support the multiplication of plant viruses. The use of enzymes to liberate protoplasts from cells by digestion of the cell wall is one of the simplest forms of cell fractionation and, pectinase and cellulase have been used in extensive degradation procedures on leaf tissue to obtain readily large quantities of nuclei fractions uncontaminated with other organelles. The isolated protoplast system is one in which marker molecules can be presented directly at the surface of the plasmalemma to a relatively uniform population of protoplasts, which can be readily handled for electron microscope observations, whether by thin-sectioning or by freeze-etching, or for biochemical assays.. By isolating protoplasts from plant tissues, a less complex system is obtained in which the initiation of virus infection and subsequent virus multiplication in a uniform population of cells can be studied.

Mucilage-producing cells in the seed coat of plantago ovata: developmental fine structure,

Abstract: A B S T R A C T As the ovule of Plantago ovata matures into a seed its epidermal cells are transformed from undifferentiated parenchyma to thin-walled containers of almost pure mucilage. During this process the volume of the cells increases 60-80 fold, and the protoplast degenerates to a remnant. Rapid cell expansion begins with pollination and is accompanied by an increase in the size of the nucleus and nucleolus, a change in the random arrangement of ribosomes, a decrease in the thickness of cell walls, and synthesis of starch. Deposition of mucilage inside vacuoles and between the plasma membrane and cell wall accompanies a marked increase in the number and size of Golgi vesicles. Histochemical evidence using the thiocarbohydrazide-osmium vapor method shows polysaccharide to be present within Golgi vesicles while they are still attached to the Golgi apparatus. Mucilage deposition is associated with further cell expansion, separation of the protoplast from the cell wall, fusion of vacuoles and extra protoplasmic space, and the disappearance of starch. TIIE OUTERMOST CELL LAYER of the seed in the genus Plantago contains little but mucilage. The seed-produced polysaccharides of several Plantago

The isolation of protoplasts from the placental cells ofSolanum nigrum L.

Abstract: Living protoplasts were isolated from the interplacental regions ofSolanum nigrum berries by the removal of the walls from cells in tissue slices treated for 1–2 hours with 12% pectinase in 033 M to 038 M sucrose solution Protoplasts thus isolated, then washed and transferred to microculture chambers for observation, invariably tended to be spherical Comparative measurements of cell and protoplast volumes revealed that 10% of the isolated structures were subunits of protoplasts From diameter changes in protoplasts studied in a hypotonic (020 M) sucrose solution, the maximum expansion of the plasma membrane was determined Slightly hypertonic solutions (033 M to 038 M sucrose) promote stability of isolated protoplasts for several days The importance to stability of osmotic concentration and ion balance in the medium is here established Probably of equal importance is the optimal combination of several common constituents of culture media Further studies on some aspects of specific medium requirements are in progress

Plant protoplasts for use in somatic cell hybridization.

Abstract: : Somatic cell hybridization is a potentially useful technique for the introduction of genetic variability into plant species. One proposed method involves fusion of plant protoplasts (which is a cell lacking its wall--defined here on the basis of light microscope examination) to form a hybrid cell which can be induced to form a plant. Plant protoplasts produced by the use of crude commercial lytic enzymes are not always healthy (as defined by consideration of factors such as cytoplasmic streaming, presence of cytoplasmic strands and position of the nucleus within the cell, in relation to survival time). Peroxidase, basic proteins and ribonuclease have been implicated as possible deleterious agents. The use of purified enzymes offers a more rigorously defined system for obtaining healthy protoplasts. Purified preparations of cellulase (EC 3.2.1.4), pectate lyase (EC 4.2.99.3) and endopolygalacturonase (EC 3.2.1.15) have been used to prepare protoplasts from a range of plant cell suspension cultures. Inducible streptomycete enzymes lytic towards plant cell walls have also been prepared. (Author)

Activity and location of two enzyme fractions during the culture cycle of Schizosaccharomyces pombe

Abstract: When cell walls of Schizosaccharomyces pombe were removed, the protoplast contained most of the ribonuclease but only about 50% of the aminopeptidase activity. In cell homogenates approximately 75%...

Electron microscopic observations on growing and dividing protoplasts of Bacillus megaterium.

Abstract: SUMMARY: Protoplasts of Bacillus megaterium grew well and divided in 1% casein hydrolysate (enzymic) medium containing 0.5 M-NaCl as the stabilizer. A fibrous layer of coat, possibly composed of murein, developed around the growing protoplast. A small protuberance then formed on the protoplast and grew until a symmetrical dumbbell-shaped body was formed. The coat did not develop around the ‘daughter’ protoplast. Division was completely inhibited in the presence of penicillin, and a coat did not develop around the protoplast. Materials which might otherwise have formed the coat in the absence of penicillin were released into the medium. After 12 h. of growth in the absence of penicillin, normal cell wall was formed around the cell, although reversion to bacillary form was not observed. The cells divided into 4 to 6 cells simultaneously by transverse septa, and intracellular membranous organelles (mesosomes) appeared within.