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N C Mishra

Publications and source records attributed to N C Mishra.

47 records · Page 3Linked to original sources
PubMed1975

Induction by RNA of inositol independence in Neurospora crassa.

The effect of purified wild-type RNA (allo-RNA) on genetic reversion of inositol-requiring mutant 89601 of Neurospora crassa is described. The mutant (inos minus) strain, on treatment with the wild-type RNA preparation, was found to revert to wild type (inos+) in significant numbers. RNA from the mutant (iso-RNA) and allo-RNA digested by RNase were ineffective in causing genetic reversion at the inositol locus. The allo-RNA-induced revertants were stable and showed a Mendelian transmission of the inos+ character.

Inositol↗
PubMed1973

Non-Mendelian inheritance of DNA-induced inositol independence in Neurospora.

Inositol-independent (inos(+)) revertants of Neurospora induced in inositol-requiring mutants by treatment with wild-type DNA in previous studies were found to be stable and to grow well in the absence of inositol. Genetic data presented in this paper show that a major proportion of these induced revertants rarely transmitted the inositol independence character (inos(+)) to their sexual progeny. Non-Mendelian transmission of the transformed character (inos(+)) was also found to occur in some of the sexual progeny in subsequent generations. These genetic data support the idea that the transforming DNA pieces carrying the genetic information (called exosomes) are not readily integrated into the host genome. It is suggested that elimination of most exosomes during meiosis causes a loss of the genetic information and leads to non-Mendelian transmission of the induced revertant character (inos(+)).

Crosses, Genetic↗
PubMed1972

Effect of L-sorbose on polysaccharide synthetases of Neurospora crassa (glycogen- -1,3-glucan-morphology-cell wall-digitonin-particulate enzymes).

Neurospora glycogen synthetase (EC 2.4.1.11) occurs in 100,000 x g particles. The two forms (glucose-6-phosphate dependent-independent) of glycogen synthetase were solubilized and separated by digitonin treatment of the 100,000 x g particles. Glucan synthetase activity of Neurospora was found only in a cell-wall preparation. These two enzymes have been characterized in relation to the paramorphogenic action of sorbose. Sorbose-grown cultures showed a marked decrease in the specific activity of both enzymes, as compared to sucrose-grown wild-type cultures. Sorbose inhibited the activity of the wild-type enzymes both in vivo and in vitro. In the presence of 5 mM sorbose incorporation of [(14)C]glucose from [(14)C]uridinediphosphate glucose into glycogen by the dependent form of glycogen synthetase was completely inhibited. Thus, the paramorphogenic action of sorbose seems to result from its inhibition of these enzymes of cell-wall biosynthesis. Activities of the enzymes from the sorbose-resistant mutant, patch, were not affected by sorbose either in vivo or in vitro.

Carbon Isotopes↗
PubMed1970

Phosphoglucomutase mutants of Neurospora sitophila and their relation to morphology.

Biochemical and genetic evidence is presented that the rg-1 and rg-2 genes control the structure of the two isozymes of phosphoglucomutase (Phosphoglucomutase I and II) in Neurospora silophila. Results of kinetic and gel filtration studies show that the two phosphoglucomutases may exist in vitro either as separate or as a single but complex molecular species depending on the ionic concentration. The complex phosphoglucomutase molecule is suggested to be the physiologically active form of the enzyme. The change in the enzyme structure is discussed in relation to the morphological change in the ragged mutant strains.

Chromatography, DEAE-Cellulose↗