Protoplast

About: Protoplast is a research topic. Over the lifetime, 5474 publications have been published within this topic receiving 122468 citations.

Effect of the osmotic conditions during sporulation on the subsequent resistance of bacterial spores.

Abstract: The causes of Bacillus spore resistance remain unclear. Many structures including a highly compact envelope, low hydration of the protoplast, high concentrations of Ca-chelated dipicolinic acid, and the presence of small acid-soluble spore proteins seem to contribute to resistance. To evaluate the role of internal protoplast composition and hydration, spores of Bacillus subtilis were produced at different osmotic pressures corresponding to water activities of 0.993 (standard), 0.970, and 0.950, using the two depressors (glycerol or NaCl). Sporulation of Bacillus subtilis was slower and reduced in quantity when the water activity was low, taking 4, 10, and 17 days for 0.993, 0.970, and 0.950 water activity, respectively. The spores produced at lower water activity were smaller and could germinate on agar medium at lower water activity than on standard spores. They were also more sensitive to heat (97 °C for 5–60 min) than the standard spores but their resistance to high hydrostatic pressure (350 MPa at 40 °C for 20 min to 4 h) was not altered. Our results showed that the water activity of the sporulation medium significantly affects spore properties including size, germination capacity, and resistance to heat but has no role in bacterial spore resistance to high hydrostatic pressure.

Plant regeneration from protoplast-derived tissues of Linum usitatissimum L. (Flax).

Abstract: Protoplasts were isolated enzymatically from seedling roots, hypocotyls and cotyledons of Linum usitatissimum L. which divided to form callus. Plant regeneration was obtained from protoplast-derived tissues of root and cotyledon, but only rhizogenesis was observed in the case of protoplasts derived from hypocotyls. The ability to isolate, culture, and regenerate plants from root and cotyledon protoplasts of Linum usitatissimum L. is discussed in relation to future attempts to produce somatic hybrids between Linum species.

Plant regeneration from protoplasts of Panax ginseng (C.A. Meyer) through somatic embryogenesis.

Abstract: Protoplasts of Panax ginseng were isolated from embryos obtained from the 4-year old embryogenic cell line KCTC PCL 49031 which was derived from a zygotic embryo. High protoplast yields of 22-25 × 10(6) protoplast / g tissue were obtained following 5-6 h digestion with 2% Cellulysin, 1% Pectinase and 1% Macerasae in half strength Murashige and Skoog's medium containing 12% mannitol. A plating density of 1×10(5) protoplasts /ml was found optimal for protoplast culture. An initial division frequency of 10% was obtained in an agarosegelled defined medium. Myo-inositol (6%) was found to be the most suitable osmoticum. Somatic embryos were formed from protoplast derived embryogenic callus, which regenerated into plantlets.

Specific pools of endogenous peptides are present in gametophore, protonema, and protoplast cells of the moss Physcomitrella patens

Abstract: Protein degradation is a basic cell process that operates in general protein turnover or to produce bioactive peptides. However, very little is known about the qualitative and quantitative composition of a plant cell peptidome, the actual result of this degradation. In this study we comprehensively analyzed a plant cell peptidome and systematically analyzed the peptide generation process. We thoroughly analyzed native peptide pools of Physcomitrella patens moss in two developmental stages as well as in protoplasts. Peptidomic analysis was supplemented by transcriptional profiling and quantitative analysis of precursor proteins. In total, over 20,000 unique endogenous peptides, ranging in size from 5 to 78 amino acid residues, were identified. We showed that in both the protonema and protoplast states, plastid proteins served as the main source of peptides and that their major fraction formed outside of chloroplasts. However, in general, the composition of peptide pools was very different between these cell types. In gametophores, stress-related proteins, e.g., late embryogenesis abundant proteins, were among the most productive precursors. The Driselase-mediated protonema conversion to protoplasts led to a peptide generation “burst”, with a several-fold increase in the number of components in the latter. Degradation of plastid proteins in protoplasts was accompanied by suppression of photosynthetic activity. We suggest that peptide pools in plant cells are not merely a product of waste protein degradation, but may serve as important functional components for plant metabolism. We assume that the peptide “burst” is a form of biotic stress response that might produce peptides with antimicrobial activity from originally functional proteins. Potential functions of peptides in different developmental stages are discussed.

Influence of the nutrient medium on the recovery of dividing cells from tobacco protoplasts.

Abstract: Systematic tests resulted in a nutrient solution containing the following, in milligrams per liter, for the culture of protoplasts isolated from Nicotiana tabacum L. callus cells: Murashige and Skoog salts (T. Murashige and F. Skoog, 1962. Physiol. Plant. 15: 473-497); sucrose, 15,000; mannitol, 110,000; alpha-naphthaleneacetic acid, 0.6; kinetin, 0-0.1; thiamine.HCl, 10; pyridoxine.HCl, 10; nicotinic acid, 5; myo-inositol, 100; and glycine, 2. In this medium, regeneration of cell wall has been observed in 85% and resumption of cell division among 35% of the protoplast isolates.