Protoplast

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

From protoplasm to swarmer: regeneration of protoplasts from disintegrated cells of the multicellular marine green alga microdictyon umbilicatum (chlorophyta)1

Abstract: Protoplast regeneration from extruded cytoplasm of the multicellular marine green alga Microdictyon umbilicatum (Velley) Zanardini (Cladophorales, Anadyomenaceae) was investigated. The early process of protoplast formation is comprised of two steps: agglutination of cell organelles into protoplasmic masses followed by generation of a temporary enclosing envelope around them. Agglutination of cell organelles was mediated by a lectin‐carbohydrate complementary system. Three sugars, D-galactosamine, D-glucosamine, and � -D-mannose, inhibited the agglutination process, and three complementary lectins for the above sugars, peanut agglutinin, Ricinus communis agglutinin, and concanavalin A, bound to the surfaces of chloroplasts. Agglutination assay using human erythrocytes showed the presence of lectins specific for the above sugars in the algal vacuolar sap. A fluorescent probe 1-(4-trimethylammoniumphenyl)-6-phenyl-a, 3,5-hexatriene revealed that the envelope initially surrounding protoplasts was not a lipid-based cell membrane. However, this developed several hours later. Simultaneous fluorescein diacetate and propidium iodide staining showed that the primary envelope had some characteristics of cell membranes, such as semipermeability and selective transport of materials. Also, fluorescein diacetate staining showed esterase activity in the protoplast and relocation of cell organelles and compartmentalization of cytoplasm during the process of regeneration. Both pH 7‐9 and salinity 400‐500 mM were found to be essentially important for the development of the protoplast envelope. When the basic regeneration process was accomplished, two alternative pathways of development were seen; about 70% of one-celled protoplasts transformed into reproductive cells within 2 weeks after wounding, whereas others began cell division and grew into typical Microdictyon thalli. Quadriflagellate swarmers were liberated from the reproductive cells, and they germinated into mature individuals. It is therefore suggested that this species may use the wound response as a method of propagation and dispersal.

Production of somatic hybrids between frost tolerantSolanum commersonii andS. Tuberosum: Protoplast fusion, regeneration and isozyme analysis

Abstract: Mesophyll protoplasts ofSolanum commersonii, a frost tolerant wild species not crossable with the cultivated potato, were fused with either dihaploid or tetraploid S.tuberosum. Protoplasts were aggregated by means of alternating current (AC) or polyethylene glycol (PEG), and electrofused with three direct current (DC) pulses. The treatments with PEG/DC generally resulted in very low heterofusion frequency and protoplast viabiity. On the other hand, AC/DC fusion conditions were optimized by increasing the fusion density of protoplasts and adding CaCl2 to fusion medium. When a density of 4.8 × 105 protoplasts ml−1 was used in the fusion medium containing 0.2 mM Ca++, AC/DC treated protoplasts showed heterofusion frequencies and plating efficiencies of about 10 and 3%, respectively. Fast growing calli from AC/DC fusion experiments were further cultured for regeneration. Fifty-seven plants were regenerated and clonedin vitro as shoot cultures. Compared to parents they showed heterotic vigor and could be identified as hybrids, based on isozyme analysis.

An alginate-layer technique for culture of Brassica oleracea L. protoplasts

Abstract: Ten accessions belonging to the Brassica oleracea subspecies alba and rubra, and to B. oleracea var. sabauda were used in this study. Protoplasts were isolated from leaves and hypocotyls of in vitro grown plants. The influence of selected factors on the yield, viability, and mitotic activity of protoplasts immobilized in calcium alginate layers was investigated. The efficiency of protoplast isolation from hypocotyls was lower (0.7 ± 0.1 × 106 ml−1) than for protoplasts isolated from leaf mesophyll tissue (2 ± 0.1 × 106 ml−1). High (70–90%) viabilities of immobilized protoplasts were recorded, independent of the explant sources. The highest proportion of protoplasts undergoing divisions was noted for cv. Reball F1, both from mesophyll (29.8 ± 2.2%) and hypocotyl (17.5 ± 0.3%) tissues. Developed colonies of callus tissue were subjected to regeneration and as a result plants from six accessions were obtained.