Showing papers on "Protoplast published in 1967"
TL;DR: In the outer cap cells of roots of Zea mays, secretion is accompanied by hypertrophy of dictyosome cisternae with formation of large secretory vesicle contents, and the product moves outward through the cell wall after discharge from the protoplast, and appears as a droplet adhering to the root tip.
Abstract: In the outer cap cells of roots of Zea mays, secretion is accompanied by hypertrophy of dictyosome cisternae with formation of large secretory vesicles. Vesicle contents are subsequently released from the protoplast by fusion of the vesicle membrane with the plasma membrane. The secreted material, a highly hydrated polysaccharide, was localized intracellularly by the periodic acid-Schiff reaction. Under appropriate conditions, the product moves outward through the cell wall after discharge from the protoplast, and appears as a droplet adhering to the root tip. Under conditions where the secretory product accumulates at the inner wall surfaces, no external droplet is formed.The secretory activity has an active phase that is sensitive to metabolic inhibitors and influenced by temperature (Q10>2), and a passive phase that is independent of temperature, insensitive to metabolic inhibitors but sensitive to osmotic agents. The active phase is characterized by a temperature-independent periodicity (3 hours). Sucrose supplied to the growth medium increases the amount of polysaccharide secreted. Polysaccharide synthesis, segregation into vesicles, and discharge from the protoplast are assumed to require active metabolism; the step involving extrusion of polysaccharide through the cell wall region appears to be a passive process influenced by the degree of hydration of the polysaccharide and by cell turgor.
137 citations
TL;DR: The lytic action of lysozyme upon Bacillus subtilis walls was studied by following the disappearance of bacillary-colonies-forming units and the appearance of L-colony-forming-units, resulting in heritable propagation of the protoplast state.
Abstract: SUMMARY: The lytic action of lysozyme upon Bacillus subtilis walls was studied by following the disappearance of bacillary-colony-forming units and the appearance of L-colony-forming-units. The rapidity of cell wall removal by lysozyme fluctuated markedly during growth in a chemically defined medium, presumably because subtle changes in the cell wall were constantly occurring. When lysozyme-sensitive bacilli were grown with chloram-phenicol 10 μ./ml. for 3 hr they showed a notable increase in lysozyme resistance; at the same time, their walls almost doubled in thickness. As lysozyme attack proceeded in a given culture, the bacilli passed first through a rod-shaped osmotically sensitive stage, and then a spherical stage characterized by incomplete removal of cell wall before finally reaching the naked protoplast stage. The spherical forms with adherent wall residues formed L colonies on a medium containing the reversion inhibitor D-methionine and bacillary colonies on the same medium without D-methionine. Under the latter conditions, the cell wall residue served as a starting point for rebuilding of complete wall, much as residual wall permits reversion of Gram-negative spheroplasts to the bacillary state. In the presence of D-methionine, the feedback sequence required for wall formation was severed, resulting in heritable propagation of the protoplast state.
35 citations
TL;DR: Isolated cell membranes of the yeast Candida utilis have been found to consist largely of protein and lipids, and traces of carbohydrate and ribonucleic acid were also found.
33 citations
TL;DR: Large secretory cells are found in the pericarp ofOkra capsules and it is suggested that these cells may play a major role in the formation of okra mucilage.
Abstract: Large secretory cells are found in the pericarp of okra capsules. In early developmental stages these cells are conspicuous because of the great quantity of Golgi apparatus-derived, PAS positive substance stored between the protoplast and the cell wall. It is suggested that these cells may play a major role in the formation of okra mucilage.
31 citations
TL;DR: Candida utilis, Saccharomyces cerevisiae, S. fragilis, Pichia polymorpha, and Hansenula anomala yeast cells, harvested in the early logarithmic phase, were attacked with purified β(1–3)-glucanase from Micromonospora chalcea, which resulted in the liberation of protoplasts.
Abstract: Candida utilis, Saccharomyces cerevisiae, S. fragilis, Pichia polymorpha, and Hansenula anomala yeast cells, harvested in the early logarithmic phase, were attacked with purified β(1–3)-glucanase from Micromonospora chalcea, which resulted in the liberation of protoplasts. The treated cells were observed under the electron microscope before the protoplasts were liberated. Differences in the cell walls of the enzyme-treated and untreated cells were observed. The action of the glucanase was also tested against isolated walls of C. utilis. The enzyme attacked the S. cerevisiae cell wall in a uniform manner. The attack on S. fragilis was located in certain zones of the cell wall, where breakage occurred and through which the protoplast emerged. On the other three yeasts, an intermediate attack was observed, not as definitely located as in S. fragilis, yet less uniformly than in S. cerevisiae.
12 citations
TL;DR: The term “protoplasts” is used for a cytological speciality which covers only a small sector of the wide classical concept, as represented by the publications in the journal Protoplasma and the monographs of Plasmatologia which are concerned with all aspects of living matter.
Abstract: MICROBIOLOGISTS call yeast cells and bacteria devoid of their cell wall “protoplasts”1. According to a 100 yr old definition the protoplast represents the totality of the living cell constituents quite independent of whether the cell is coated by a wall or not. The general cytological term has therefore unfortunately been narrowed by considering the “protoplast” as the result of the removal of the cell wall. In seminars and symposia on “protoplasts”, the term is used for a cytological speciality which covers only a small sector of the wide classical concept, as represented by the publications in the journal Protoplasma and the monographs of Plasmatologia which are concerned with all aspects of living matter, and not only with the problem of whether and how the lost cell wall can be regenerated.
11 citations
TL;DR: L-form colonies could be subcultured on conventional media and required from four to six passages for complete reversion to classical parent forms and it is suggested that the replicative particle may be filtrable.
Abstract: Spheroplasts of Vibrio cholerae types Inaba, Hikojima, and Ogawa were produced in serum. An excess of lysozyme was added to expedite transformation, and CaCl2 was used as the stabilizing agent. At the optimal time for each strain, when less than 1% classical rod forms were observed microscopically, samples were plated on both conventional and modified L-form media. No growth occurred on conventional media; L-form type colonies appeared on L-form media after 2 to 6 days of incubation. L-form colonies could be subcultured on conventional media and required from four to six passages for complete reversion to classical parent forms. Reaction mixtures of Hikojima and Inaba types were passed through membrane filters (0.45 μ); L-form colonies were grown from both strains after spheroplast transformation. Appropriate controls were negative. It is suggested that the replicative particle may be filtrable.
7 citations
TL;DR: Protoplast-bursting factor lysed the protoplasts of Gram-positive bacteria, but not the spheroplasts of gram-negative bacteria, and did not decrease the surface tension of saline even in high concentrations.
6 citations
TL;DR: The conditions in which macromolecular RNA could be taken up by the intact yeast protoplast were investigated and an RNA preparation isolated from protoplasts of Saccharomyces carlsbergensis, in which the enzyme αglucosidase had been induced, was added to non-induced protoplast.
Abstract: IN an attempt to demonstrate the presence and the biological activity of a specific (α-glucosidase-) messenger RNA in yeast RNA preparations, the conditions in which macromolecular RNA could be taken up by the intact yeast protoplast were investigated. No pinocytosis in yeast cells has yet been reported1; in the yeast cytoplasmic membrane, however, invaginations and vesicles—in other organisms these are thought to be the organelles responsible for pinocytosis—have been observed2–4. In order to study both uptake and biological activity, an RNA preparation isolated from protoplasts of Saccharomyces carlsbergensis, in which the enzyme αglucosidase had been induced5, was added to non-induced protoplasts.
5 citations
TL;DR: The lipid composition of the cell membrane from Microbacterium ammoniaphilum was determined by thin-layer and column chromatographies to make clear the relation between saturated fatty acids/unsaturated fatty acids and the nature of the membrane.
Abstract: An l-glutamic acid (l-GA)-forming bacterium. Microbacterium ammoniaphium was cultured in the molasses medium with or without poiyoxyethylene fatty acid esters to obtain l-GA-accumulating cells or non-accumulating cells, respectively.Then protoplast-like bodies (PLB) were prepared from each group of cells by reacting them with egg white lysozyme.l-GA-accumulating reaction by the PLB was carried out under high and low osmotic pressures.From the results of the experiment, it was shown that the difference in the ability of l-GA accumulation between l-GA-accumulating cells and non-accumulating cells was attributed mainly to the difference in the nature of the cell membrane.Further, the relationship between the molar ratio of saturated fatty acids/unsaturated fatty acids which was reported previously and the nature of the membrane was discussed.The lipid composition of the cell membrane from Microbacterium ammoniaphilum was determined by thin-layer and column chromatographies to make clear the relation between ...
2 citations
TL;DR: Protoplast-bursting factor has a little antibacterial activity and is capable of inhibiting the growth of Bacillus megaterium, and leakage of various cellular components into the surrounding menstruum occured when the cell suspension was subjected to treatment with P. B. factor.
Abstract: Protoplast-bursting factor (P. B. factor) has a little antibacterial activity and is capable of inhibiting the growth of Bacillus megaterium. The cell suspensions required P. B. factor and Mg++ for the oxidation of glucose-6-phosphate but did not require them for that of glucose. Leakage of various cellular components into the surrounding menstruum occured when the cell suspension was subjected to treatment with P. B. factor. These materials were identified as protein, deoxyribonucleic acid, ribonucleic acid, and amino acids. Under an electron microscope, the cytoplasm of the cells treated with P. B. factor was apparently less dense than the control, which seemed to suggest that the cytoplasm had leaked out of the inside of the cell through the membrane by the treatment of P. B. factor.
TL;DR: In spite of the interest displayed in fungal protoplasts and protoplast-like forms, the pot ho genie fungi continues to be the focus of research.