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Z Lorkiewicz

Publications and source records attributed to Z Lorkiewicz.

At least 37 records · Page 2Linked to original sources
PubMed1978

Nitrogen fixation by Rhizobium in pure cultures.

Strains of Rhizobium trifolii and Rhizobium meliloti were tested for their asymbiotic nitrogen fixation ability. From among ten tested strains two R. trifolii and one R. meliloti expressed nitrogenase activity within the range of 1.3--9.3 nM C2H4/h/mg protein. Asymbiotic nitrogen fixation was affected by the composition of the medium.

Nitrogen Fixation↗
PubMed1978

Genetic transformation in Rhizobium trifolii.

Markers controlling the synthesis of amino acids and organic bases as well as streptomycin resistance and sensitivity to acriflavine were transformed in Rhizobium trifolii. The results indicate that the str marker was transformed independently of leu, his, ade and trp markers. Co-transformation of leu and utra markers ranged from 3 to 7%, whereas that of thi and acr was 10%.

Acriflavine↗
PubMed1978

Genetic mapping of the chromosome of Rhizobium trifolii.

Cultures of the wild strain and auxotrophic mutants of Rhizobium trifolii T37 synchronized by means of phenylethanol have been mutagenized with nitrosoguanidine. Fifteen genetic markers were characterized in respect of their order and the time of replication based on the peaks of mutations of the genes. The time of R. trifolii chromosome replication was estimated using inhibitors of the initiation of DNA replication: rifampicin, chloramphenicol and phenylethanol. The replicative map of R. trifolii chromosome has been constructed. Taking into account the replicative map, linkages of the genes, and the bidirectional model of the Rhizobium chromosome replication, a circular genetic map of the chromosome of R. trifolii T37 was elaborated.

Chloramphenicol↗
PubMed1977

Transfer of R1drd19 plasmid from Escherichia coli J53 to Rhizobium trifolii by conjugation.

Rldrd19 plasmid was transferred by conjugation from Escherichia coli J53 to Rhizobium trifolii T24, T26 and 24XSM strains with frequency 10(-3) to 10(-5). The R. trifolii exconjugants carrying Rldrd19 were in turn able to transfer the R factor by conjugation to other R. trifolii strains. Rldrd19 was maintained stably in R. trifolii. R. trifolii 24XSM, T26 and 14M were also found to harbor an endogenous plasmid (molecular weight 5.5 megadaltons) with undetermined as yet properties. Ridrd19 could be stably maintained in the same cell together with the endogenous plasmid.

Ampicillin↗
PubMed1976

Plasmid deoxyribonucleic acid in Rhizobium trifolii.

In deoxyribonucleic acid of Rhizobium trifolii centrifuged in cesium chloride-ethidium bromide equilibrium was found a sattelite peak containing covalently closed circular deoxyribonucleic acid. The plasmid had a molecular weight of about 64 x 10(6) shown by sedimentation in sucrose gradients and electron microscopy.

DNA↗
PubMed1976

Cell wall lipopolysaccharide response to the ColIb plasmid mutants.

Mutants of ColIb plasmid affected the synthesis of O-side chains of lipopolysaccharides (LPS) in Salmonella. The plasmid srd 25 (defective in colicin synthesis) caused a significant decline of rhamnose and mannose content and lack of abequose in LPS of S. typhimurium. The number of repeating units in O-side chains was decreased after the indroduction of srd 25. Cultures of S. typhimurium and S. enteritidis harboring drd2 (derepressed in colicin production) polymerised dideoxyhexose-defective O-side chains i.e. deprived of abequose and tyvelose, respectively. In dideoxyhexoseless S. meleagridis the content of rhamnose and mannose were reduced. The information for the alterations of Salmonella LPS was contained in the plasmid genome. In the wild-type plasmids the genes controlling the O-antigen changes were not expressed.

Cell Wall↗
PubMed1976

Segregation of Col Ib and drd7 into minicells.

The wild-type plasmid ColIb and its mutant drd7 derepressed in conjugation were transferred to Escherichia coli K12 P678-54 which produces minicells. Fertility functions of drd7 remained derepressed in the new host. P678-54drd7 transmitted the plasmid at a high frequency (28.6%) and it was effectively lysed by the phage If1. Significant amounts of 3H-DNA segregated from P67854Col+ into minicells dependent upon the presence of the plasmid. The depressed plasmid segregated more effectively into minicells than the wild-type plasmid. ColIb segregated into 2% whereas ColIbdrd7 into 8.4% of minicells. The difference in the frequency of segregation of the wild-type and the derepressed plasmid indicated different cell membrane attachment sites of each plasmid studied. Mini-drd7 were able to transfer the plasmid to E. coli Row at a low frequency (0.1%). Minicells carrying either of plasmid were capable to synthesize RNA and protein. RNA and protein synthesis were plasmid specific and the precursors were not incorporated into minicells without plasmids. Rifampin and chloramphenicol inhibited RNA and protein synthesis in minicells, respectively. The more effective incorporation of 3H-uridine or 14C-leucine into minicells harboring drd7 than ColIb resulted presumably from the high efficiency of the segregation of drd7 into minicells. Polyacrylamide gel electrophoresis of 3H-RNA has shown that plasmids in minicells were able to code low molecular RNA of 4s. No 16 or 23 ribosomal RNA was found in the profiles of de novo synthesized RNA in minicells.

Bacterial Proteins↗
PubMed1975

Plasmid-determined alterations of Salmonella typhimurium lipopolysaccharides.

Salmonella typhimurium Rc902 infected with derepressed ColIb mutants gave rise to changes in the composition of bacterial lipopolysaccharides (LPS). Bacteria carrying ColIbdrd7, derepressed in transfer, exhibited a marked decrease in the content of all 0-side-chain sugars of LPS. Similar effect were found upon the introduction of R64-11, also derepressed in transfer. In LPS of S. typhimurium containing ColIbdrd2, derepressed in colicin synthesis, a decrease of abequose content associated with an increase of glucose level was observed. Bacteria carrying the wild-type ColIb, the revertant of a drd mutant to the wild type, or the non colicinogenic strain resulting from the elimination of ColIbdrd2, showed no changes in the sugar composition of LPS.

Bacteriophages↗
PubMed1975

Studies on phage 1P receptors in Rhizobium trifolii and Rhizobium leguminosarum.

The rate of phage 1P attachment to Rhizobium cell walls was increased in the presence of ethylenediaminetetraacetic acid (EDTA). On the other hand the rate of adsorption of phage 1P to the Triton -- insoluble cell walls was diminished. The subsequent treatment of cell walls with 2% Triton X-100 and 5mM EDTA caused a more substantial decline of the phage inactivating capacity. Lipopolysaccharides (LPS) isolated from the sensitive strains, contrary to those from phage-resistant mutants, inactivated effectively phage 1P. The content of sugars in LPS preparations was determined by using gas liquid chromatography.

Adsorption↗
PubMed1974

Fatty acids present in the lipopolysaccharide of Rhizobium trifolii.

Approximately 70% of the fatty acids recovered after acid or alkaline hydrolysis of the lipopolysaccharide of Rhizobium trifolii were hydroxy fatty acids identified as hydroxymyristic and hydroxypalmitic acids. Palmitic acid was the only saturated fatty acid found in the lipopolysaccharide of R. trifolii. Octadecenoic and a small amount of hexadecenoic acids were also identified. The results of BF(3) methanolysis and hydroxylaminolysis suggest that hydroxypalmitic acid is N-acyl bound.

Chromatography, Gas↗