Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Protoplasts”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources
PubMed1991

[Protoplasts of lincomycin producer Streptomyces roseolus in genetic manipulations].

Protoplasts of commercial strain No. 1 of Streptomyces roseolus producing lincomycin were prepared. Conditions for protoplast storage and regeneration were defined. The protoplasts of strain No. 1 mutants marked by the rifampicin and thiostrepton resistance and the ability to synthesize melanin pigments were fused. Genetic analysis of the recombinants was performed. Systems for transformation of S. roseolus protoplasts by plasmid DNAs were developed. Efficiency of transformation by pIJ702, pIJ61, pVG101 and pBG3 and stability of the transformants were shown.

Cells, Cultured↗
PubMed1989

Differentiation of potato (Solanum tuberosum L.) plants from cultured leaf protoplasts.

Through induction of totipotent stage in cultured cells plants were regenerated from protoplast derived callus colonies of potato. Growing of the plants in vitro with optimal aeration and pretreatment of the leaves in dark and cold prior to protoplast isolation has improved the protoplast yield and frequency of cell division. Protoplasts of four potato genotypes have started to divide within 2-5 days after plating them into culture medium containing 2,4-D (0.2 mg/l); ZEA (0.5 mg/l); and NAA (1 mg/l) as growth regulators. Embedding of the cells into agarose proved to be favourable to avoid cell browning and to increase colony formation. The series of hormone treatments based on complex action of NAA and BAP promoting colony growth and greening, ZEA and IAA inducing shoot redifferentiation, and GA3 plus NAA supporting shoot elongation and rooting, finally resulted in high frequency of plant regeneration from microcolonies.

Plant Cells↗
PubMed1989

[Use of Streptomyces sp. 26-115 protoplasts inactivated by heating in fusion experiments].

When heated at 55 degrees C for 30 or 60 minutes protoplasts of auxotrophic mutants of Streptomyces sp. 26-115 producer of actinomycin C (active and inactive variants) lost their capacity for regeneration. The protoplasts heated at at 55 degrees C for 30 minutes and not for 60 minutes maintained some ability to yield recombinants on fusion under the effect of PEG 6000. Unlike the parent active strain, the colonies formed by the spores of the prototrophs yielding on fusion of the intact protoplasts showed wide ranges of antibiotic activity against M. flavus while a significant part of the colonies was inactive. The use of the inactive variant protoplasts heated at 55 degrees C for 30 minutes in the fusion procedure increased the proportion of the inactive variants.

Hot Temperature↗
PubMed1988

[Selection of strains of Streptomyces griseus Kr., the producer of a streptothricin antibiotic grisin, using the method of protoplast fusion].

The effect of protoplasting on antibiotic activity of the grisin-producing organism was shown. High frequency of Grn- mutants after strain VG307f protoplasting and no capacity in these mutants for reversion to the initial Grn+ phenotype were shown. The reversion frequency was less than 10(-8). Moreover, it was shown that all the Grn- mutants lost their stability (GrnR) to the effect of their own antibiotic. With respect to strain VG212 there was noted a significant increase in the number of both the minus and the plus variants after the protoplast formation and regeneration. Fusing of protoplasts of strains VG307f and VG212 belonging to the divergent lines in selection of S. griseus Kr. yielded the phage stable strain VG7849 with high levels of the antibiotic production and improved technological properties.

Anti-Bacterial Agents↗
PubMed1988

[Use of the method of protoplast fusion in the selection of a nisin producer].

Experimental data on selection of Streptococcus lactis producing the polypeptide antibiotic nisin with the method of protoplast fusing, one of the modern methods of cell engineering are presented. Four strains of Streptococcus lactis differing in their nisin-producing levels and difficult for protoplasting were used in the study. It was shown possible to transfer them to the protoplast form when respective conditions for their preliminary cultivation and regeneration are provided. Distinctive features of these strains with respect to the antibiotic resistance, sugar fermentation and growth component requirements were revealed. The protoplast fusing yielded hybrids differing from the parent strains by a number of phenotypical features and nisin-synthesizing activity.

Genetic Engineering↗
PubMed1988

[The methods of protoplast formation and transformation of Streptomyces strains].

Factors influencing formation, regeneration and transformation of protoplasts in streptomyces are described. Conditions for formation and regeneration of protoplasts in 4 industrial strains producing the macrolide antibiotic tylosin were studied. It was demonstrated possible to apply the method for transformation of the S. lividans type culture to 3 industrial strains of S. griseus producing grisin, an antibiotic used as a feed additive. Potential increasing of the efficiency of protoplast transformation and transfection in various actinomycetous strains including industrial ones is discussed. The stimulating effect of lyposomes on transformation of protoplasts in S. lividans 66 with DNA of plasmids pVG101 and pIJ350 as well as transfection with DNA of phages SH10 and KS404 was shown. The tylosin resistance genes in S. fradiae strain B45 were cloned which enabled isolating the cluster of the genes participating in tylosin biosynthesis.

Cloning, Molecular↗
PubMed1988

Factors affecting protoplast release from some mesophilic, thermophilic and thermotolerant species of filamentous fungi using Novozym 234.

Factors affecting the release of protoplasts from mycelia of Aspergillus fumigatus, Aspergillus niger, Penicillium ochrochloron and Geosmithia emersonii were investigated. Protoplast yields were found to be greatly dependent on the growth temperature, incubation conditions, lytic enzyme system, mycelial age and mycelial concentration. High yields of protoplasts were obtained from all four organisms after a 3 h incubation with 1 mg/ml Novozym 234 in 0.1 M 2-N-[morpholino] ethane sulphonic acid (MES) buffer at pH 5.0, containing 0.6 M sodium chloride. Supplementation of the incubation medium with 0.03 M calcium chloride enhanced protoplast release in P. ochrochloron but not in the other three fungi.

Aspergillus fumigatus↗
PubMed1977

[Lysis of yeast protoplasts under sodium alkyl sulfates treatment].

The lytic action of homologous series of sodium alkyl sulfates on yeast protoplasts was studied. The concentration dependences study allowed to estimate the lytic concentrations C50 of the agents required for the 50% lysis of protoplasts in the suspension. The data concerning the agents micelle formation in the lytic medium allowed to make some suggestions and to produce a model of the lytic action of alkyl sulfates on the plasma membrane of the protoplasts. The amounts of the agents absorbed on the membrane and involved in the interaction followed by the membrane breakdown in the model are evaluated. On the basis of the data obtained it is concluded that sodium dodecyl sulfate displays the highest lytic activity to the yeast protoplast plasma membrane as compared to the other alkyl sulfates used in the study. The results obtained are discussed in terms of the effect of yeast cell wall on the extraction of intracellular proteins from intact yeast cell under sodium alkyl sulfates action.

Kinetics↗
PubMed1986

[Production and regeneration of yeast protoplasts: a review].

The latest advance in protoplast technology results from a long and detailed study of cell wall composition and protoplast systems relating to their isolation and culture. The reports on protoplast preparation and fusion discussed in this review clearly demonstrate the applicability of technique for the genetic manipulation of microorganisms. These points have been demonstrated in Candida strains. The behaviour of protoplasts especially with respect to reversion could be an additional factor that operates during selection. Furthermore the fusion technique, in providing a mechanism which genetic recombination can be readily achieved, should be of great potential in empirical breeding and strain improvement. These aspects are reviewed.

Cell Wall↗
PubMed1986

A comparative study of protoplast preparation and regeneration in Streptomyces rimosus and Streptomyces lividans.

One of the basic techniques for DNA cloning in Streptomyces is the preparation of protoplasts and the efficient regeneration of normal mycelia. In order to develop an oxytetracycline producing S. rimosus strain as a host for molecular cloning, the efficiencies of protoplast preparation and cell wall regeneration were compared with those obtained using S. lividans, the host for the majority of cloning experiments. The results presented suggest that the S. rimosus strain selected is a convenient host for the cloning of recombinant DNA, at least in relation to the preparation and regeneration of protoplasts. Interestingly, the size of the protoplasts was dependent upon the physiological age of the mycelium in S. rimosus; no such dependence was observed in S. lividans.

Cloning, Molecular↗
PubMed1985

Production and regeneration of protoplasts from Cryptococcus.

Protoplasts were quickly and efficiently produced from both varieties of Cryptococcus neoformans and from C. laurentii by use of the multi-enzyme product Novozym 234. Conditions for regeneration of protoplasts are described. DNA yield from the Novozym-produced protoplasts was superior to that from snail gut enzyme-derived protoplasts.

Cryptococcus↗
PubMed1977

[Lysis of bacterial protoplasts and spheroplasts and suppression of their dehydrogenase activity by neotehomycin].

Neotelomycin induced lysis of the protoplasts of Bac. megaterium and inhibited their succinate dehydrogenase activity. Direct correlation between the lytic activity of the antibiotic and its effect on succinate dehydrogenase was found. Neotelomycin had no effect on the dehydrogenase activity of the protoplast lysates. Possibly, suppression of the protoplast succinate dehydrogenase of Bac. megaterium under the effect of neotelomycin was due to significant structural changes caused by the antibiotic in the protoplast membranes and leading to their lysis and not to the direct effect on the enzyme. Neotelomycin had practically no effect on the spheroplast dehydrogenase activity of E. coli resistant to the antibiotic and did not induce their lysis. Resistance of E. coli to neotelomycin must be associated not with the presence of the antibiotic non-permeable cell wall but the peculiar properties of the membrane cytoplasm.

Anti-Bacterial Agents↗
PubMed1977

[Certain data on the protoplast ultrastructure].

A study was made of the structure of Bac. subtilis and Listeria monocytogenes protoplasts by the method of scanning electron microscopy. The mechanism of protoplast formation in Gram-positive bacteria and in spheroplasts of Gram-negative bacteria proved to differ. A loss of the rigid form of the cell, round protrusions on cell surface, and an escape of the cytoplasm through the ruptured cell wall in some one place was noted in case of protoplasts. Individual cells can coalesce with one another with the formation of shapeless masses. The formation of small spheroid bodies by budding, and also a division of protoplasts by constriction was described.

Bacillus subtilis↗
PubMed1983

[Use of the protoplast fusion method in the selection of Streptomyces griseus--the producer of the streptothricin antibiotic grisin].

An effective method for protoplast fusion in S. griseus producing grisin was developed. The method requires the use of polyethylene glycol with a molecular weight of 1000. It was demonstrated that protoplasts formed most effectively in this organism, when the mycelium of the streptomycete previously treated with ultrasound in the process of its growth was used for the treatment with lysozyme. The efficacy of protoplast regeneration in the strains with the use of the modified hypertonic medium R2MD was 25-75 per cent. The possibility of using the protoplast fusion method for constructing phage resistant strains producing kormogrisin was shown.

Anti-Bacterial Agents↗
PubMed1984

[Regeneration of Nocardia orientalis protoplasts].

A method for effective regeneration of the protoplasts of N. orientalis, a vancomycin-producing organism into viable cells on a rich organic medium was developed. The dependence of the regeneration on the conditions of the protoplast plating out and the level of the regeneration medium dehydration was studied. The highest positive effect was observed when the protoplasts were suspended in the agarized medium and then plated out on the regeneration medium dehydrated by 2.5 per cent. The frequency of the protoplast regeneration increased on addition of bovine serum albumin to the regeneration medium. The effect of bovine serum albumin depended on its concentration. When the albumin concentration was optimal (0.01 per cent) the regeneration amounted to 100 per cent.

Culture Media↗
PubMed1984

[Isolation and regeneration of Micromonospora olivoasterospora protoplasts].

The conditions for preparation and regeneration of the protoplasts of M. olivoasterospora were developed. It was found that effective formation of the protoplasts required preliminary cultivation of M. olivoasterospora in the medium containing glycine in a concentration inhibiting its growth at least by 60-80 per cent. The strains studied markedly differed in their sensitivity to glycine and were highly sensitive to it. The efficacy of the protoplast formation depended on the culture age and increased with the use of the lytic enzyme 3 of Cytophaga dissolvens. The possibility and advisability of the use of prolonged lysis of the Micromonospora cell walls were shown. A rich organic medium was used for regeneration of the protoplasts.

Cell Fractionation↗
PubMed1978

Protoplasts from Acetabularia: isolation and fusion.

Protoplasts were isolated from cells of Acetabularia cliftonii, which are presumed to be haploid. The release of the protoplasts occurred after treatment of the cells with papain or proteinase K. They are genuine protoplasts since they contain a nucleus. Fusion was initiated by mechanically pushing together two protoplasts. Under these conditions, the efficiency of fusion was more than 90% within 30 minutes at room temperature. Haploid cells from one cyst, i.e., cells which eventually would have formed gametes of the same mating type, exhibit a greater propensity for fusion as compared to haploid cells from different cysts.

Acetabularia↗
PubMed1984

The effect of laser microsurgery on cytoplasmic strands and cytoplasmic streaming in isolated plant protoplasts.

Cytoplasmic strands of actively streaming isolated callus derived protoplasts of higher plants were subjected to laser microsurgery. Typically, the irradiated strand retracted and cytoplasmic streaming stopped in the entire cell. At the same time, all cytoplasmic strands disintegrated, and formerly not totally spherically shaped protoplasts became spherical. This result indicates tension as a stability factor of cell shape and the cytoplasmic make-up and demonstrates that the nonspherical shape of these protoplasts is not due to cell wall residues. Cytoplasmic streaming as well as the strands were quickly reestablished and often the irregular shape of the protoplast appeared again. Treatment of unirradiated cells with cytochalasin B showed similar effects. The results are discussed with respect to the involvement of cytoskeletal elements in cytoplasmic streaming and organization.

Cytochalasin B↗