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Biomedical subjects

M Kowalski

Publications and source records attributed to M Kowalski.

At least 91 records · Page 5Linked to original sources
PubMed1983

Symbiotic properties of adenine requiring mutants of Rhizobium meliloti strain L5-30.

From the effective and prototrophic Rhizobium meliloti strain L5-30 two auxotrophic mutants were isolated: RM4 and RM221. These two mutants required adenine and adenine with thiamine for their growth, respectively. Both mutants nodulated lucerne plants ineffectively. Electron microscopic observations of the nodule tissue showed that its cells were not occupied by bacteria. Prototrophic revertants and transductants of these mutants showed high symbiotic effectiveness. It is assumed that adenine or adenine and thiamine requirements made impossible release of bacteria from the infection thread.

Adenine↗
PubMed1983

Chromosomal gene controlling symbiotic nitrogen fixation in Rhizobium meliloti L5-30.

Auxotrophic Rhizobium meliloti strain RM 246 carries two independent mutations: in the biosynthesis of cysteine (cys) and symbiotic nitrogen fixation process (fix). These two mutations were mapped by transduction between his-240 and ade-4 markers. Cotransduction frequencies show the following order of genes: his-240 fix-1 cys-246 ade-4.

Chromosome Mapping↗
PubMed1978

Restoration of effectiveness of R. meliloti ineffective mutants by transduction of high level streptomycin resistance.

Rhizobium meliloti lysine dependent mutant, L5-30lys, was ineffective and this mutation was not cotransducible to lys. Transduction of chloramphenicol and linked temperature sensitive mutations did not change its symbiotic properties. Subsequent transduction of high level streptomycin resistance restored its effectiveness. Streptomycin resistance marker was linked to chloramphenicol resistance and temperature sensitive markers.

Chloramphenicol↗
PubMed1977

Auxotrophic mutations related to symbiotic properties of Rhizobium meliloti strain L5-30.

Mutants isolated from effective R. meliloti strain L5-30 which required histidine (his-240), arginine+uracil (arg-55) and cysteine (cys-243, cys-244 and cys-246) showed also loss of effectiveness. Mutant requiring isoleucine+valine (ilv-74) was non-infective. Relation of the metabolic deficiency to the symbiotic properties of these mutants was tested comparing symbiotic response of their prototrophic revertants and transductants. It was found that all revertants and transductants of the strain his-240 were effective which suggests that histidine deficiency was the cause of their ineffectiveness. All revertants and transductants of the cysteine mutants were still ineffective. This result indicates two independent mutations which were not cotransductible. Prototrophic revertants of the mutant arg-55 were ineffective whereas 56.9 percent of transductants appeared effective suggesting close linkage of two mutations. i.e. auxotrophic and the other concerned with symbiotic effectiveness. Though one of 69 prototrophic transductants obtained from the non-nodulating mutant ilv-74 remained non-nodulating, it seems that changes in nodulating ability of the mutant are related to the auxotrophic requirements.

Histidine↗
PubMed1977

Structure of nodules induced by auxotrophic and ineffective mutants of Rhizobium meliloti strain L5-30 requiring cysteine, arginine+uracil and histidine.

Nodules produced by ineffective mutants of R. meliloti strain L5-30 requiring arginine+uracil (arg-55) and cysteine requiring mutants (cys-243, cys-244, cys-246) studied under light microscopy were found to be occupied by bacteria. This indicates on defect in transformation of these mutants into N2 fixing bacteroids. These defects were not associated with auxotrophy. In the nodules induced by histidine requiring mutant (his-240) only few host plant cells were occupied by bacteria. This indicate that his-240 mutant is defective in liberation from the infection thread and its multiplication since supplementation of the plant growth medium with 50 microgram/ml of L-histidine enabled establishment of fully effective association. Prototrophic transductants and revertants were fully effective.

Amino Acids↗
PubMed1977

Cystic fibrosis: a new outlook. 70 patients above 25 years of age.

We have presented a group of 70 patients over 25 years of age as of January 1, 1975, who were diagnosed as having cystic fibrosis (CF) at various ages from birth to 28 years. Some patients were diagnosed late in life in spite of classical symptoms and a characteristic history of the disease. Patients with CF present with a broad spectrum of symptoms which vary considerably in severity. This older age group represents approximately 10% of our current roster of patients with CF. This disease is no longer confined to early life and will continue to be seen with increasing frequency in older patients. Our experience with this disease indicates that a number of affected individuals can attain adulthood and find a useful place in society. The quality of life provided to these adults is illustrated in their intellectual, socioeconomic achievements and marital life. Our aim has been to recognize the disease as early in life as possible and to provide a comprehensive medical program which includes all aspects of health care.

Adult↗
PubMed1975

Renal tubular excretion of triethylcholine (TEC) in the chicken: enhancement and inhibition of renal excretion of choline and acetylcholine by TEC.

1. [3H]-triethylcholine (TEC) was actively transported by the renal tubule of the chicken at a rate 85% that of simultaneously administered p-aminohippuric acid (PAH). 2. TEC was demonstrated to be transported by the organic cation transport system in the kidney through inhibition with quinine and the bio-cation choline. 3. When the infusion of TEC was increased to 2 times 10(-6) mol kg(-1) min(-1) reaching the infused kidney, the transport of [3H]-TEC was inhibited, suggesting that an excretory transport maximum for TEC in the renal tubules had been reached. 4. The excretion of both choline and acetylcholine was enhanced by TEC loads as low as 1 times 10(-18) mol kg(-1) min(-1). Enhancement continued as TEC infusion was increased up to approximately 1 times 10(-7) mol kg(-1) min(-1) at which point this enhancement was converted to inhibition. 5. Possible mechanisms for the biphasic effect of TEC on organic cation transport are discussed.

Acetylcholine↗