Topic
Protoplast
About: Protoplast is a research topic. Over the lifetime, 5474 publications have been published within this topic receiving 122468 citations.
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TL;DR: It is concluded that the observed formation of prototropic bacteria is due to protoplast fusion, a process which does not induce prophage development, and that the only stable products of the resulting diploid state are haploid recombinants.
Abstract: Prototrophic Bacillus subtilis cells can be formed in the presence of DNase as a result of cell fusion occurring in mixed populations of protoplasts derived from two parental strains which are both nutritionally-complementing and polyauxotrophic. No prototrophs ever appear from mixed nonprotoplasted bacteria, or from the auxotrophic parental protoplasts plated separately. The frequency of prototroph formation, which is appreciable only when the mixed protoplasts are exposed to polyethylene glycol treatment, may exceed 1 X 10(-4) of the total protoplast population initially present, which is 1 to 4 X 10(-3) of those protoplasts which reverted to the bacillary form. It is strongly dependent on the number and chromosomal location of the markers used in the selection of the prototrophs, and it is unaffected when either one of the parental strains bears the phage phi105 in the inducible prophage state. No auxotrophic bacteria, parental or otherwise, were found as segregants from repeatedly isolated protrotrophic clones growing in a nonselective medium. Unselected markers segregate among the selected recombinants. It is concluded that the observed formation of prototropic bacteria is due to protoplast fusion, a process which does not induce prophage development, and that the only stable products of the resulting diploid state are haploid recombinants.
182 citations
TL;DR: A finely dispersed cell suspension was obtained from anther-derived rice callus cultured in AA medium, which contained an amino acid mixture as the sole nitrogen source and promoted the release of protoplasts effectively.
182 citations
TL;DR: It was proved that the protoplasts prepared from mesophyll of Nicotiana tabacum are infected by tobacco mosaic virus, with the efficiency of infection exceeding that by mechanical inoculation of tobacco leaves.
Abstract: It was proved that the protoplasts prepared from mesophyll of Nicotiana tabacum are infected by tobacco mosaic virus. The infection occurred when purified tobacco mosaic virus particles were added to a protoplast suspension in the presence of poly-L-ornithine. The virus multiplied in these protoplasts to a level of 106 virus particles per infected protoplast during 24 hours of incubation. The efficiency of infection was remarkably high, exceeding that by mechanical inoculation of tobacco leaves.
173 citations
TL;DR: A reproducible and efficient transformation system has been developed for maize that is based on direct DNA uptake into embryogenic protoplasts and regeneration of fertile plants from protoplast-derived transgenic callus tissues and introduction of introduced foreign genes in the genomic DNA of the transformants.
Abstract: A reproducible and efficient transformation system has been developed for maize that is based on direct DNA uptake into embryogenic protoplasts and regeneration of fertile plants from protoplast-derived transgenic callus tissues. Plasmid DNA, containing the β-glucuronidase (GUS) gene, under the control of the doubled enhancer element (the −208 to −46 bp upstream fragment) from CaMV 35S promoter, linked to the truncated (up to −389 bp from ATG) promoter of wheat, α-amylase gene was introduced into protoplasts from suspension culture of HE/89 genotype. The constructed transformation vectors carried either the neomycin phosphotransferase (NPTII) or phosphinothricin acetyltransferase (PAT) gene as selective marker. The applied DNA uptake protocol has resulted at least in 10–20 resistant calli, or GUS-expressing colonies after treatment of 106 protoplasts. Vital GUS staining of microcalli has made possible the shoot regeneration from the GUS-stained tissues. 80–90% of kanamycin or PPT resistant calli showed GUS activity, and transgenic plants were regenerated from more than 140 clones. Both Southern hybridization and PCR analysis showed the presence of introduced foreign genes in the genomic DNA of the transformants. The chimeric promoter, composed of a tissue specific monocot promoter, and the viral enhancer element specified similar expression pattern in maize plants, as it was determined by the full CaMV 35S promoter in dicot and other monocot plants. The highest GUS specific activity was found in older leaves with progressively less activity in young leaves, stem and root. Histochemical localization of GUS revealed promoter function in leaf epidermis, mesophyll and vascular bundles, in the cortex and vascular cylinder of the root. In roots, the meristematic tip region and vascular tissues stained intensively. Selected transformants were grown up to maturity, and second-generation seedlings with segregation for GUS activity were obtained after outcrossing. The GUS-expressing segregants carried also the NPTII gene as shown by Southern hybridization.
172 citations
TL;DR: Routine procedures for the isolation of large numbers of protoplasts from an established cell culture of Zea mays and for the induction of sustained divisions leading to secondary cell cultures have been developed.
Abstract: Routine procedures for the isolation of large numbers of protoplasts from an established cell culture of Zea mays and for the induction of sustained divisions leading to secondary cell cultures have been developed. The critical factors seem to be associated with neither specific enzymatic conditions for the isolation nor specific culture conditions for the protoplasts but with the ‘quality’ of the culture used for protoplast isolation.
172 citations