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Biomedical subjects

J Barciszewski

Publications and source records attributed to J Barciszewski.

At least 109 records · Page 6Linked to original sources
PubMed1988

Comparative calorimetric studies on the dynamic conformation of plant 5S rRNA. I. Thermal unfolding pattern of lupin seeds and wheat germ 5S rRNAs, also in the presence of magnesium and sperminium cations.

An attempt has been made to correlate differential scanning calorimetry melting profiles of 5S rRNAs from lupin seeds (L.s.) and wheat germ (W.g.) with their structure. It is suggested that the observed differences in thermal unfolding are due to differences in RNA nucleotide sequence and as a consequence in higher order structures. Interesting effects induced by magnesium cation, perprotonated and permethylated sperminium tetracations are discussed. It is suggested that the difference in the stabilizing effect of the three cations results from different mode of their interactions with RNA. "Pure" electrostatic interactions expected for permethylated tetracations are rather weak due to the steric hindrance around each positively charged nitrogen atom. Electrostatic interactions of the other two cations are significantly enhanced by coordination bonding for magnesium and by hydrogen bonding for protonated sperminium cation.

Calorimetry, Differential Scanning↗
PubMed1988

Yellow lupin cytoplasmic tRNAGlu is not a cofactor in chlorophyll biosynthesis.

Yellow lupin seeds (Lupinus luteus) cytoplasmic tRNAGlu was isolated and the primary structure was determined to be: (sequence in text) AGU CCCGGCGACGGAACCAOH. It is 76 nucleotides long and contains 8 modified nucleosides: 2 residues of pseudouridine, ribothymidine, 3 dihydrouridines, 5-methylcytosine and 1-methyladenosine. This tRNAGlu assayed in delta-aminolevulinic acid synthesis was shown to be inactive. Its structural features are discussed.

Base Sequence↗
PubMed1986

The primary structure of wheat germ tRNAArg--the substrate for arginyl-tRNAArg:protein transferase.

Besides its major role in protein synthesis, wheat germ arginyl-tRNAArg can serve as an amino acid donor in an enzymatic reaction to bovine serum albumin catalysed by the enzyme arginyl-tRNAArg: protein transferase. The nucleotide sequence of the tRNAArg involved in this reaction was determined to be: pG-A-C-U-C-C-G-U-m1G-m2G-C-C-C-A-A-D-Gm-G-A-X-A-A-G-G-C-m2(2) G-C-U-G-G-U-Cm-U-I-C-G-m2A-A-A-C-C-A-G-A-G-A-D-U-m5C-U-G-G-G-T-psi -C-G-m1 A-U-C-C-C-C-A-G-C-G-G-A-G-U-C-G-C-C-AOH. We suggest that the decapentanucleotide 5'-G-U-Pu-m2G-C-N-C-A-A-D-Gm-G-A-X-A-3', localized in the D-region, interacts specifically with the protein transferase.

Acyltransferases↗
PubMed1985

Effects of plant transfer ribonucleic acids on interferon production.

An optimal interferon (IFN) production was obtained at concentrations of 50 micrograms/ml poly I:C and 2000 micrograms/ml DEAE dextran in Lpa cells. It was shown that methionine initiator tRNA (tRNAiMet) in a dose 50 micrograms/ml or crude tRNA (tRNAc) applied to Lpa cell during the stages of IFN induction, IFN induction and synthesis, as well as during IFN synthesis resulted in a continuous IFN production for up to 24 hr. Exposure of the cells to 150 micrograms/ml tRNAiMet during the stages of IFN induction and IFN induction and synthesis caused total inhibition of IFN production. This effect was partially observed only after the high dose of tRNAc. Addition of a high dose of tRNAiMet or tRNAc to cells during the synthesis stage caused no inhibition but prolongation of IFN production.

Animals↗
PubMed1982

Chemical probes for tRNA tertiary structure. Comparative alkylation of tRNA with methylnitrosourea, ethylnitrosourea and dimethylsulfate.

The tertiary structure of tRNA in solution can be proved by chemical modification experiments. Three reagents, N-ethyl-N-nitrosourea, N-methyl-N-nitrosourea and dimethylsulfate which are known to alkylate nucleic acids at nucleophilic centers were compared. It is found that N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea mainly react with phosphate residues and dimethylsulfate only with the bases. With dimethylsulfate the extent of alkylation of guanosines is about one order of magnitude higher than that of the phosphates by the nitroso compounds.

Alkylating Agents↗
PubMed1982

Interaction of alkaloids with plant transfer ribonucleic acids. Effect of sparteine on lupin arginyl-tRNA formation.

The effect of the alkaloid sparteine on arginyl-tRNA formation was studied. It was demonstrated that sparteine sulfate in the concentration range 10-60 mM inhibits the charging reaction when amino acid, ATP and tRNA are used as variable substrates. The mode of action is different for all pattern of inhibition for all varied substrates is generally uncompetitive. A pattern of inhibition for all varied substrates is generally uncompetitive. A non-competitive mechanism for amino acid and tRNA was observed at low sparteine concentration, but in the case of ATP it is also uncompetitive.

Alkaloids↗
PubMed1982

The influence of tRNA on interferon induction by poly I:C in Lpa cells.

The kinetics of interferon production, induced by poly I:C in the presence of DEAE dextran, was studied in Lpa cells. Optimal interferon production was obtained at concentration of 10 micrograms/ml poly I:C and 200 micrograms/ml DEAE dextran. Transfer RNA applied to Lpa cells during induction and synthesis of interferon resulted in continuous production of interferon for 24 hrs. The application of tRNA to cells during the shutoff of interferon synthesis had no effect on the kinetics of interferon production.

Animals↗
PubMed1980

A simple method for the recovery of active oligomeric enzyme from its diluted solutions.

A method for the recovery of active enzyme from its diluted solutions is described. It includes batch sorption on DEAE-Sephadex A-50 which follows elution or chromatography of an enzyme on a DEAE-Sephasex A-50 column. All purified aminoacyl-tRNA synthetases retain high activity without degradation of the protein. The method is very fast and convenient.

Amino Acyl-tRNA Synthetases↗