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PubMed1964

FATE OF THE MESOSOMES OF BACILLUS MEGATERIUM DURING PROTOPLASTING.

Fitz-James, Philip (University of Western Ontario, London, Canada). Fate of the mesosomes of Bacillus megaterium during protoplasting. J. Bacteriol. 87:1483-1491. 1964.-When cells of Bacillus megaterium growing rapidly in peptone medium are treated with sucrose buffer prior to protoplasting, their membranous organelles or mesosomes are extruded as a collection of vesicles into the wall-membrane interspace. On subsequent protoplast formation with lysozyme digestion, the mesosome remnants become dispersed. If glucose is added to the peptone, a slightly more persistent mesosome can be seen and photographed by phase microscopy during lysozyme digestion, either as a wall-attached granule or as a protoplast tag. In thin section, mesosomes are found as small, variably dispersed aggregates of vesicles and wall-like material. Complete protoplasts are usually free from internal mesosomes but may contain twists or everted pockets of membrane on their periphery. By lysozyme digestion of partially fixed cells, the empty mesosome pockets in the membrane can be demonstrated in rod-shaped protoplasts.

Bacillus megaterium↗
PubMed1967

Growth and division of protoplasts of Bacillus megaterium and inhibition of division by penicillin.

Protoplasts of Bacillus megaterium grew well and divided in nutrient broth containing 0.5 m NaCl as the stabilizer. Protoplasts also grew when sucrose or succinate was used instead of NaCl; however, no division phenomena were observed. The sequence of growth and division was similar to the results obtained by McQuillen. Protoplasts enlarged from 1.8 to 3.5 mu in diameter, and then a small protuberance formed in the enlarged cells. The nodules enlarged until eventually symmetrical dumbbell-shaped bodies were formed, which then separated into two daughter protoplasts having a diameter of about 2.5 mu. Deoxyribonucleic acid and ribonucleic acid were halved during division. Penicillin inhibited the division of protoplasts, though the growth was not influenced by the drug. Membrane-bound amino sugar content was considerably reduced when the cells were grown in the presence of penicillin. These results suggest that organized murein formed on the protoplasts membrane may play an important role in the septation process.

Bacillus megaterium↗
PubMed1981

Isolation of protoplasts from Aspergillus nidulans conidiospores.

Protoplasts were prepared from conidiospores of Aspergillus nidulans. The mononucleated conidia gave protoplasts of a uniform size, approximately 5-micron diameter, depending on the strain and the stabilizing medium used. Conidia were preincubated with 2-deoxy-D-glucose in a minimal medium at 37 degrees C for 3 h. The swollen conidia were collected, resuspended in a buffer containing 0.4 M (NH4)2SO4 as stabilizer, and incubated with Oerskovia lytic enzymes at 30 degrees C for 3 or 4 h. Approximately 80% of the conidia were converted into protoplasts. The protoplasts were separated from cell wall fragments and intact conidia by centrifugation over 30% sucrose. This isolation procedure gives a suspension of mononucleated or binucleated protoplasts suitable for recombination experiments and other studies for which a homogenous protoplast suspension is required. The procedure was also successful for Aspergillus niger.

Aspergillus nidulans↗
PubMed1994

Fission yeast protein kinase C gene homologues are required for protoplast regeneration: a functional link between cell wall formation and cell shape control.

Two novel protein kinase C (n PKC) gene homologues, pck1+ and pck2+ were isolated from the fission yeast Schizosaccharomyces pombe (Toda et al. (1993) EMBO J. 12, 1987). We examined the functional differences of pck1+ and pck2+ in cell wall formation and actin organization of S. pombe. Regenerating protoplasts of a wild-type strain, single gene disruptants of pck1+ (delta pck1) and pck2+ (delta pck2) were used as a simple model to examine the functional links between PKC, cell wall formation and actin organization. Protoplasts of the wild-type strain and those of delta pck1 reverted to intact cells in osmotically stabilized liquid medium. A close spatial association between new cell wall formation and actin was observed in these two strains. In delta pck2, protoplasts did not revert to intact cells: (1) scarcely any new cell wall material was formed; (2) actin was not reorganized; and (3) nuclear division and an increase in the amount of cytoplasm were observed in the regenerating protoplasts. These findings demonstrate that the pck2+ gene has a function essential for protoplast regeneration but the pck1+ gene does not. Involvement of n PKCs in cell wall formation and actin organization was also clarified. The effect of staurosporine (a potent inhibitor of protein kinases) on regenerating protoplasts of the three strains confirmed the assumption that the pck2 protein is an in vivo target of staurosporine in the fission yeast.

Actins↗
PubMed1997

Actions of pokeweed antiviral protein on virus-infected protoplasts.

Pokeweed antiviral protein (PAP) belongs to a group of ribosome-inactivating proteins (RIPs) that inactivate ribosomes by depurinating rRNA at a specific site. To study the mechanism for the antiviral activity of PAP, the actions of PAP on TMV-infected and uninfected tobacco protoplasts were investigated. The addition of 0.33 microM PAP to TMV-inoculated protoplasts caused a complete inhibition of TMV production. The same concentration of PAP was found to inhibit protein synthesis in the virus-infected protoplasts and to kill the cells, but it had no effect on the uninfected protoplasts. The concentration dependence of protein synthesis-inhibition by PAP was related to that of inhibition of viral multiplication. Furthermore, two other RIPs (ricin A-chain and luffin-a), which showed 240 and 430-fold less activity on tobacco ribosomes than PAP in a cell-free system, did not inhibit viral multiplication even at a concentration of 3.3 microM. The analysis of RNAs from the virus-infected and PAP-treated protoplasts demonstrated that 25S rRNA was depurinated by PAP in the infected cells. These results suggest that PAP, which is normally unable to penetrate the plasma membrane of uninfected protoplasts, gains entrance to the cytosol of infected cells and prevents viral multiplication by inactivating ribosomes.

Animals↗
PubMed2006

Guard cell protoplasts: isolation, culture, and regeneration of plants.

Guard cell protoplasts have been used extensively in short-term experiments designed to elucidate the signal transduction mechanisms that regulate stomatal movements. The utility of uard cell protoplasts for other types of longer-term signal transduction experiments is just now being realized. Because highly purified, primary isolates of guard cell protoplasts are synchronous initially, they are uniform in their responses to changes in culture conditions. Such isolates have demonstrated potential to reveal mechanisms that underlie hormonal signalling for plant cell survival, cell cycle re-entry, reprogramming of genes during dedifferentiation to an embryogenic state, and plant cell thermotolerance. Plants have been regenerated from cultured guard cell protoplasts of two species: Nicotiana glauca (Graham), tree tobacco, and Beta vulgaris, sugar beet. Plants genetically engineered for herbicide tolerance have been regenerated from cultured guard cell protoplasts of B. vulgaris. The method for isolating, culturing, and regenerating plants from guard cell protoplasts of N. glauca is described here. A recently developed procedure for large-scale isolation of these cells from as many as nine leaves per experiment is described. Using this protocol, yields of 1.5-2 x 10(7) per isolate may be obtained. Such yields are sufficient for standard methods of molecular, biochemical, and proteomic analysis.

Culture Media↗
PubMed1988

Plant protoplasts immobilized in calcium alginate: a simple method of preparing fragile cells for transmission electron microscopy.

A simple method for electron microscopic preparation of plant protoplasts is described. The main problems in preparing these fragile protoplasts for electron microscopy have been cell collapse due to steep gradients between protoplasts and fixatives and unacceptable loss of material during the many steps of the procedure. These problems may be solved by immobilization of the protoplasts in calcium alginate beads. The free diffusion properties of this gel prevent steep gradients. The beads also simplify handling and prevent loss of material. Protoplasts isolated from hypocotyls of rape, Brassica napus (var. Niklas), have been used as a model system. Transmission electron microscopy of the immobilized protoplasts osmotically stabilized with glucose demonstrated adequate structural and ultrastructural preservation.

Alginates↗
PubMed2025

Development of a highly efficient protoplast regeneration and transfection protocol for enhancing CRISPR genome editing of Brassica carinata.

Brassica carinata is an important oil crop with significant potential for food and industrial production. The application of the CRISPR/Cas9 genome editing tool in B. carinata could accelerate its breeding cycle. However, no efficient DNA-free gene editing method currently exists for this species. Protoplast-based CRISPR editing presents a promising solution, though it is often challenging for many crop species. In this study, we investigated several critical factors influencing in vitro shoot regeneration, including genotype, sugar type, selection and combination of plant growth regulators (PGRs), and culture duration on different media throughout various stages of protoplast development. As a result, we developed a highly efficient, five-stage protoplast regeneration protocol for B. carinata based on specific stages of protoplast development. Key findings of this study include the requirement for high concentrations of NAA and 2,4-D in the initial medium (MI) for cell wall formation, while a lower auxin concentration relative to cytokinin was necessary for active cell division (MII). For callus growth and shoot induction, a high cytokinin-to-auxin ratio was essential (MIII), and an even higher cytokinin-to-auxin ratio was optimal for shoot regeneration (MIV). For shoot elongation, low levels of BAP and GA3 were sufficient (MV). Our results also demonstrated that the duration of culture on different media and maintaining appropriate osmotic pressure at the early stages were crucial for successful protoplast regeneration. With this optimized protocol, we achieved an average regeneration frequency of up to 64% and a transfection efficiency of 40% using the GFP marker gene. This efficient protoplast regeneration protocol is now being employed for genome editing in our lab and is expected to significantly enhance the application of the CRISPR system in both basic research and the genetic improvement of B. carinata over the long term.

Brassica carinata↗
PubMed1989

Preparatory studies for the use of plant protoplasts in space research.

An experiment using plant protoplasts has been accepted for the IML-1 mission to be flown on a space shuttle in 1991. Preparatory experiments include studies of cell wall formation, cell division, the effect of simulated weightlessness using fast and slow rotating clinostats, and the development and testing of hardware for the IML-1 mission. After 24 h at 25 degrees C, protoplasts isolated from hypocotyls or leaves of rapeseed seedlings, or from carrot suspension cells, show 60, 20 and 15% cell wall formation, respectively. The time course of formation of the cell wall and cell division could be delayed by treatment at low temperatures or immobilization in alginate or agarose. This aspect is of importance in connection with problems of late access to the space shuttle before launch. At 4 degrees C only 18% of the rapeseed hypocotyl protoplasts had formed cell walls after 24 h. Protoplasts immobilised in agarose or alginate gradually regain their cell division capacity and after 72 h the frequencies are 51 and 26%, respectively, compared to non-immobilised control protoplasts. A significant decrease in cell division activity is observed after rotation for 6 h on the slow clinostat. A similar effect is not observed on the fast clinostat. Protoplasts, cultured in the specially designed plant chamber for up to 14 days established cell aggregates which have further developed into plants.

Alginates↗
PubMed1992

[Protoplast fusion in Streptomyces fradiae strains producing neomycin and tylosin].

Interspecies fusion of protoplasts of the Streptomyces fradiae strains producing neomycin (an aminoglycoside antibiotic) and tylosin (a macrolide antibiotic) was performed with a view to isolate strains producing novel antibiotics. Fusion of the protoplasts of the neomycin- and tylosin-producing strains labelled by the resistance to monomycin and lincomycin, respectively, caused no formation of stable strains producing antibiotics differing in chromatographic mobility from the antibiotics produced by the initial strains. In fusion of the protoplasts of the unlabelled strains, heat-inactivated protoplasts of the active line of one strain (donor) and native protoplasts of the inactive line of the other strain (recipient) were used. When the neomycin-producing culture was used as a recipient the fusion led to formation of strain 195-34 producing antibiotics of the benzo(a)anthraquinone group. One of these antibiotics, i.e. antibiotic 34-I, proved to be a novel biologically active substance. After regeneration of the protoplasts of the initial strains, no stable strains producing antibiotics differing from neomycin and tylosin were isolated.

Drug Resistance, Microbial↗
PubMed1990

[Preparation and characteristics of protoplasts of Streptomyces kanamyceticus].

To prepare actively regenerating protoplasts of S. kanamyceticus, the influence of the conditions of the mycelium cultivation, the culture age, lytic conditions, composition of the regeneration medium, the procedure of the culture inoculation to the regeneration medium and other parameters were studied. The study resulted in development of optimal conditions for preparation of S. kanamyceticus protoplasts in a number of 1.10(9) protoplasts per ml. The cultivation on the ST medium with 10 to 15% sucrose and addition of glycine up to 1% for 30 hours (the stationary growth phase) followed by treatment of the culture with lysozyme in an amount of 2 mg/ml for 1 hour at 32 degrees C provided preparation of up to 100% of actively regenerating protoplasts free of mycelium fragments. The size of the protoplasts increased up to 1.5 micron against the usually observed size of 0.7 to 1.0 micron with using modified lyzing buffer with 20% of sucrose according to the method recommended for S. erythreus. However, 50 to 70% of the protoplasts had point of linear regions in the cell walls, which suggested that spheroplasts were mainly forming and the phenomenon was associated with the characteristic properties of the strain cell wall structure.

Cell Count↗
PubMed1989

Isolation and cultivation of protoplasts of Caloglossa leprieurii.

Protoplasts, as important media in genetic engineering, had been isolated from some genera of seaweeds in the beginning of this decade. Using a mixed enzyme solution composed of 3% Sea snail enzyme, 3% Cellulase Onozuka R-10, 1% Macerozyme and 0.5% Pectinase, viable protoplasts were isolated from Caloglossa leprieurii (Mont) J. Ag. (Ceramiales, Rhodophyta). The viability of protoplast was determined by its exclusion of Evans Blue stain. The absence of cell walls were observed in the protoplasts, and were determined by Calcofluor White, reduced osmolarity, electron microscopic examination and self-fusion. About half of the protoplasts survived and divided at a high rate when they were cultivated in a thin liquid layer of modified medium No.5 (MES as basic medium, supplemented with MS medium, vitamins and 1ppm IAA, 1.5 ppm KT). Regenerated plantlet appeared after 45 days. Tetrasporangia appeared in the blade of some regenerated plants after 4 months. Due to its properties of Being large, polynucleal and regenerative, protoplasts of C. leprieurii offer a good prospect in the field of cell fusion and genetic operation of seaweeds.

Cell Division↗
PubMed1989

[Synthesis of heat-shock proteins in Saccharomyces cerevisiae protoplasts].

The effect of cellular capsule elimination in Saccharomyces cerevisiae yeasts (protoplast formation) on the heat-shock protein synthesis and the synthesis of the proteins in protoplasts were studied. The methods of mono- and dimeric electrophoresis have demonstrated that (1) about 18 heat-shock proteins with the molecular masses 26-98 Kd are synthesized in cells at 41 degrees C; (2) protoplast formation per se does not induce the synthesis of heat-shock proteins, but the induction of these proteins in protoplasts at 41 degrees C is similar to the one in intact cells. The protoplast formation induces the synthesis of specific proteins different from heat-shock proteins and the synthesis is inhibited by the heat-shock. The heat-shock induces modification of 88 and 86 Kd heat-shock proteins. It inhibits the synthesis of a number of peptides (15-50 Kd) in cells and protoplasts.

Electrophoresis, Polyacrylamide Gel↗
PubMed1987

[Effect of protoplast formation on the antibiotic activity of the Streptomyces fradiae 165 strain--a producer of tylosin].

Streptomyces is characterized by genetic instability evident from high frequency of changes in various properties of secondary metabolites occurring spontaneously or under the influence of certain factors. Protoplast formation is one of such factors. The paper is concerned with the influence of protoplast formation and subsequent regeneration into the mycelial form on antibiotic potency of S. fradiae strain 165. It was shown that protoplast formation led to changes in antibiotic potency of separate colonies and shifts in the potency in the direction of its increasing. The antibiotic potency of certain variants after protoplast formation was 2 to 2.5 times higher than the initial one. Changes due to protoplast formation of S. fradiae strain 165 were not stable and lost after 4-5 passages on agar media. Comparative restriction analysis of total DNA of the variants with different potency levels did not provide detection of changes in the genome of the strains isolated after protoplast formation.

Culture Media↗
PubMedDate not supplied

[Fractional protein makeup of Candida utilis yeast protoplasts in the process of their growth and development].

Candida utilis IBFMY-405 was grown in a synthetic medium with glucose. Cells taken at the logarithmic phase of growth were studied. The cells were treated with the enzyme from Helix pomatia to prepare protoplasts which were separated by differential centrifugation into groups according to their size. Three protein fractions were isolated from each group and the amino acid composition of the proteins was determined. Proteins of the first fraction (cytoplasmic) prevailed in all of the protoplast groups while the content of proteins of the second fraction (intermediate or myosin-like) was the lowest. As the size of protoplasts increased, difference in the quantitative content of proteins from the first and second fractions became less pronounced. The content of proteins of the third fraction was 3.6 and 2.4 times higher in the protoplasts of the medium size than in the largest protoplasts. The amino acid composition of each protein fraction differed quantitatively and qualitatively in all of the protoplast groups.

Amino Acids↗
PubMed1977

[Variation of cell membrane lipid composition by means of lipid transfer proteins. Properties of the protoplast membrane of Micrococcus lysodeikticus after incorporation of phosphatidylcholine].

After incorporation of phosphatidylcholine (PC) into the protoplast membrane of M. lysodeikticus by protein mediated transfer from PC liposomes, the activity of some membrane bound respiratory chain enzymes was studied. It was found that incorporation of PC decreases the rates of oxidation of exogenous substrates (NADH, malate) but the level of endogenous respiration was not changed. Ferricyanidreductase activity of ghosts of M. lysodeikticus was not dependent upon the PC content of protoplasts. PC containing protoplasts showed a higher osmotic stability than unmodified protoplasts. It is concluded that the incorporation of PC into the protoplasts results in resealing, i. e. in the repair of local defects in the protoplast membrane.

Cell Membrane↗
PubMed1984

[Effect of gramicidin S and its derivatives on protoplasts of Bacillus subtilis].

The lysis of Bacillus subtilis protoplasts by gramicidin S, a membrane active antibiotic, and its derivatives was studied according to free amino groups of the ornithine residue. The initial antibiotic and guanylgramicidin , a positive charge-preserving derivative, had a high lytic activity. Succinylgramicidin , a gramicidin S derivative with acid properties, and carbomoylgramicidin , a neutral derivative, actively lysed B. subtilis protoplasts suspended in 1/15 M phosphate buffer solution with sucrose . No lytic activity of succinylgramicidin was observed with respect to B. subtilis protoplasts suspended in an aqueous solution of sucrose. Comparative study on the sensitivity of the protoplasts of Micrococcus lysodeikticus, B. megaterium and B. subtilis to the lytic action of gramicidin S and its derivatives showed in the main a similar character of their interaction with the membranes of the protoplasts of the taxonomically close species (B. megaterium and B. subtilis). It is likely that the specificity of the action of the above substances on the protoplasts of M. lysodeikticus, i. e. a complicated character of the dependence of the lytic action of gramicidin S on its concentration, manifestation of the lytic activity of the neutral and acid derivatives in the presence of phosphates or other salts and in sucrose aqueous solution was mainly defined by the properties of the micrococcal membranes.

Bacillus megaterium↗
PubMed1983

[Characteristic features of protoplast formation and regeneration in Fusidium coccineum].

The methods for preparation and regeneration of protoplasts were tested with respect to the strains of F. coccineum markedly differing in their capacity for antibiotic production, sporulation and the growth rate. It was found that the substrate used for the culture growth had a significant effect on the cell wall and sensitivity of the mycelium to lytic enzymes. An enzyme from Hellix pomatia and its combination with lysozyme were used for lysing the culture. The cytological investigation of the time course of the culture lysis revealed a stage-by-stage pattern of protoplast formation by means of fragmentation of the hyphal contents till a ball was formed. Two to 4 protoplasts differing in their size and structure were formed within a cell. The pH value and osmotically stabilizing component had some effect on the rate of protoplast formation. Highly productive strains were characterized by formation of protoplasts heterogenous in their size and by decreased frequency of regenerations. The enzyme-free protoplasts preserved their viability and capacity for germination in osmotically stabilizing media for 72-96 hours of storage at 4 degrees C. On solid media the regeneration frequency reached 38 per cent. The regenerated cells formed colonies morphologically similar to those of the intact culture.

Aspergillus nidulans↗