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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: Plasmid DNA-mediated transformation of vegetative cells of Bacillus thuringiensis was studied with the following two plasmids: pBC16 coding for tetracycline resistance and pC194 expressing chloramphenicol resistance, which resulted in a much faster and 3 orders of magnitude more efficient method.
Abstract: Plasmid DNA-mediated transformation of vegetative cells of Bacillus thuringiensis was studied with the following two plasmids: pBC16 coding for tetracycline resistance and pC194 expressing chloramphenicol resistance. A key step was the induction of competence by treatment of the bacteria with 50 mM Tris hydrochloride buffer (pH 8.9) containing 30% sucrose. Transformation frequency was strongly influenced by culture density during the uptake of DNA and required the presence of polyethylene glycol. Growth in a minimal medium supplemented with Casamino Acids gave 35 times more transformants than growth in a rich medium. The highest frequencies were obtained with covalently closed circular DNA. With all parameters optimized, the frequency was 10(-3) transformants per viable cell or 10(4) transformants per microgram of DNA. Cells previously frozen were also used as recipients in transformation experiments; such cells gave frequencies similar to those obtained with freshly grown cells. The procedure was optimized for B. thuringiensis subsp. gelechiae, but B. thuringiensis subsp. kurstaki, B. thuringiensis subsp. galleriae, B. thuringiensis subsp. thuringiensis, and B. thuringiensis subsp. israelensis were also transformed. Compared with protoplast transformation, our method is much faster and 3 orders of magnitude more efficient per microgram of added DNA.
42 citations
TL;DR: Intergeneric hybrids of Saccharomyces cerevisiae and Z. fermentati presented characteristics of both parents, such as resistance to certain drugs and the ability to grow with either cellobiose or lactic acid as the sole carbon source; they were very stable, even under nonselective conditions and may have important industrial applications as good fermenting strains.
Abstract: To obtain strains that are able to efficiently produce ethanol from different carbohydrates, mainly cellulose hydrolysates, several species of the genus Candida and a Zygosaccharomyces fermentati strain were examined for their ability to utilize cellobiose and produce ethanol, as well as for their thermotolerance and the possibility of genetic manipulation. Candida obtusa and Zygosaccharomyces fermentati tolerated the maximal temperature for growth, possessed the highest cellobiase activity, and offered the possibility of genetic manipulation, although neither of them proved to be a good producer of ethanol. Intergeneric hybrids of Saccharomyces cerevisiae and Z. fermentati were obtained after protoplast fusion. They were selected as prototrophic strains, after isolation of auxotrophic mutants from Z. fermentati and fusion with an S. cerevisiae strain which was also auxotrophic. The hybrids, which appeared at a frequency of 2 X 10(-7), presented characteristics of both parents, such as resistance to certain drugs and the ability to grow with either cellobiose or lactic acid as the sole carbon source; they were very stable, even under nonselective conditions. These hybrids may have important industrial applications as good fermenting strains.
42 citations
TL;DR: Four cell lines derived from Nicotiana tissue with 2n=24, 48, or 72 were established and retain stable chromosome number and could be regenerated to recover plants that retained the somatic chromosome number during culture.
Abstract: Cell suspension cultures of Nicotiana were initiated using conditions designed to selectively favor stable chromosome number. These conditions included use of leaf explants to initiate cultures, growth of cells in culture medium containing 2,4-D, and transfer of cells with short subculture intervals. Four cell lines derived from Nicotiana tissue with 2n=24, 48, or 72 were established and retain stable chromosome number. Each line could be regenerated to recover plants that retained the somatic chromosome number during culture. Establishment of haploid and diploid cell lines with stable chromosome number is important for mutant isolation and protoplast fusion.
42 citations
TL;DR: Laccase could be the only effective polymerizing enzyme during the first day of protoplast culture and could contribute in the first steps of healing in wounded leaves, substituting for POX activity in cell wall reconstitution when hydrogen peroxide is not yet available.
42 citations
TL;DR: Somaclonal variation in the Borszczagowski line of Cucumis sativus L. was determined for five regeneration systems: micropropagation (MP), direct leaf callus regeneration (DLR), leaf callUS regeneration (LCR), recurrent leaf calluses regeneration (RLCR) and direct protoplast regeneration (DPR).
Abstract: Somaclonal variation in the Borszczagowski line of Cucumis sativus L was determined for five regeneration systems: micropropagation (MP), direct leaf callus regeneration (DLR), leaf callus regeneration (LCR), recurrent leaf callus regeneration (RLCR), and direct protoplast regeneration (DPR) The frequency at which new phenotypes appeared in R1 lines and the stability of the rDNA region analysed using of five probes were investigated MP was not subject to change, while DLR caused only infrequent changes The highest frequency of change arose through DPR (90% of lines) and RLCR (428%), as opposed to 59% with LCR Tetraploids were produced only in the case of LCR (47%) and RLCR (28%)
42 citations