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R Rudner

Publications and source records attributed to R Rudner.

At least 37 records · Page 2Linked to original sources
PubMed1981

Mutagenesis during transformation of Bacillus subtilis. I. An increase in "selfing' resulting from hybrid donor DNAs.

Reverse mutations increase when competent Bacillus subtilis cells are transformed with high concentrations of homologous "selfer' DNA. A high proportion of the mutants were also transformants of linked genes. A stimulation in the appearance of reversed mutations occurred when homoduplex and heteroduplex "selfer' DNAs were used as donors. Digestions of native and hybrid DNAs with nuclease S1 from Aspergillus oryzae resulted in the preferential decrease of mutations as compared to a much smaller inactivation of single marker transformation. Among various repair-deficient strains of B. subtilis, only poly A mutants showed a preferential effect of either suppressing or stimulating the frequency of reverse mutation induced by "selfer' DNA. The results are consistent with mutagenic errors occurring during gap-filling steps in the process of either mismatch repair or recombinational strand exchanges.

Aspergillus oryzae↗
PubMed1981

Mutagenesis during transformation of Bacillus subtilis. II. An increase in chemically-induced mutations during competency.

During the development of competency in Bacillus subtilis there was an increased sensitivity to methyl methanesulfonate (MMS) treatments. The frequency of reverse mutation also increased among the MMS-revertible markers by a factor of 100 as compared to vegetative cultures. The frequency of 2-aminopurine(AP)-induced mutagenesis was the same in competent and noncompetent cultures. Studies with DNA-polymerase-deficient mutants showed a direct involvement of DNA polymerase I in promoting MMS and transformation-induced mutagenesis in competent cells.

2-Aminopurine↗
PubMed1979

Intrastrand self-complementary sequences in Bacillus subtilis DNA.

Intrastrand self-complementary sequences have been isolated from the DNA of Bacillus subtilis by hydroxyapatite (HA) chromatography following thermal renaturation of strands separated by chromatography on methylated albumin kieselguhr (MAK). The instrastrand structures derived from the MAK H strand (HA HII) were biologically active showing transforming activity for a wide variety of markers, as well as hybridization to both pulse-labelled and ribosomal RNA. Removal of regions of single-strand DNA with S1 nuclease did not significantly alter the biological activity of the self-annealed molecules. The overall efficiency of transformation and hybridization of the intrastrand self-annealing DNA was low suggesting that many sequences in the population are neither active in transformation to prototrophy nor transcribed into RNA.

Bacillus subtilis↗
PubMed1978

Transformation in Bacillus subtilis with nitrogen mustard crosslinked DNA. Effect on cotransformation and mutation frequencies.

Bacillus subtilis DNA was treated in vitro with nitrogen mustard and the crosslinked molecules were purified, after alkali denaturation, by hydroxyapatite chromatography. When tested for the ability to transform the trpC2-hisB2 segment, these molecules exhibited a decrease in the cotransformation index (r) as compared to native or renatured DNA. The decrease in r was not accompanied by an increase in mutagenicity.

Bacillus subtilis↗
PubMed1978

Asymmetric transcription during post-germinative development of Bacillus subtilis spores.

The relative transcription from L and H strands of Bacillus subtilis DNA during consecutive stages of spore outgrowth was determined and compared to the transcription pattern during log-phase growth of vegetative cells. Pulses of [3H] uridine were administered during early, middle and late outgrowth phases of germination and the RNAs isolated. The asymmetry ratio of H/L as determined by hybridization at saturating RNA/DNA inputs showed a gradual decrease. During the period studied (10-90 and 90-160 min post-induction), about 50 and 35%, respectively, of the radioactive RNA consisted of ribosomal RNA transcripts. The decrease in the H/L asymmetry ratio was due predominantly to the appearance and accumulation of L strand transcripts and not to either changes in the quantity of H strand transcripts nor to fluctuation in the rate of rRNA synthesis.

Bacillus subtilis↗
PubMed1978

Asymmetric transcription during post-germinative development of Bacillus subtilis spores. II. Hybrid competition analyses.

Hybrid-competition analyses were done to estimate the relatedness of 3H-labeled mRNA species synthesized during spore germination and log-phase growth. The competitions showed that early in the germination process 10--15 and 1--3% of the RNA transcribed from the H and from the L strand, respectively, were unique and absent during log-phase growth. At later stages, the amounts of the germination-specific H transcripts decreased more rapidly than the L transcripts. The competitions with pulse-labeled log-phase RNAs showed that vegetative genes were transcribed more rapidly from the H strand than from the L strand. Most of the results could be correlated with the observed decrease in the H/L asymmetry ration during spore germination.

Bacillus subtilis↗
PubMed1973

Chromatographically fractionated complementary strands of Bacillus subtilis deoxyribonucleic acid: biological properties.

Biological, physical, and chromatographic properties of methylated albuminkieselguhr (MAK)-fractionated complementary strands, designated as light (L) and heavy (H), of Bacillus subtilis deoxyribonucleic acid (DNA) are presented. The pattern of transforming activity along the MAK elution profile of alkilidenatured DNA shows that the residually active molecules selectively fractionated ahead of the L strand fraction, whereas the most active self-annealed molecules fractionated preferentially at the trailing end of the H strand fraction. The restoration rate of transforming activity in the late-eluting H molecules was rapid and independent of concentration during the annealing reaction. The data suggest that the self-annealing activity in the H strand is due in part to the formation of intrastrand secondary structures. Hydroxyapatite chromatography of self-annealed L and H strands yielded a major fraction (I) of highly purified strand preparations devoid of transforming activity and hypochromicity, and a minor "nativelike" fraction (II). Sedimentation velocity measurements show that, in addition to the mutual complementary nature of the L and H fractions, they differ in molecular size and possibly configuration.

Bacillus subtilis↗
PubMed1973

Chromatographically fractionated complementary strands of Bacillus subtilis deoxyribonucleic acid: transformation of hybrids.

The annealing properties as measured by the restoration of transforming activity and hypochromicity of methylated albumin-kieselguhr (MAK)-fractionated complementary strands of Bacillus subtilis deoxyribonucleic acid (DNA) are presented. Temperature-absorbance measurements performed on annealed mixtures of various L and H strand fractions indicated the existence of a complementarity gradient between the two MAK peaks. The markers purA16, leu-8, metB(5), thr-5, and the linked marker hisB(2)-try-2 exhibited different bimodal distributions on MAK columns. The transforming efficiency of heteroduplex mixtures, prepared by cross-annealing resolved complementary strands of wild-type and recipient DNA, was compared. The transforming efficiency of the wild-type L and H strands was equal in one preparation and unequal in a second preparation. It was found that in the second strand preparation the heteroduplex DNA containing the H strand from wild type was more efficient for all of the markers tested. The variations in transforming efficiencies of the complementary strands in heteroduplex molecules reported here and by others are due in part to strands of unequal length and probably to the self-annealing property of the H strands. At present, no conclusion could be made regarding the existence of strand selection bias during integration of donor DNA in competent B. subtilis cells.

Bacillus subtilis↗
PubMed1972

Distribution of pyrimidine oligonucleotides in strands L and H of Bacillus subtilis DNA.

The distribution of pyrimidine oligodeoxynucleotide clusters in L and H strands of Bacillus subtilis DNA separated by methylated albumin-Kieselguhr has been determined. Preparations of native and single-stranded DNA were degraded with diphenylamine in formic acid, and the released isostichs with the general formula of Py(n)P(n+1) were separated on DEAE-cellulose by chain length. Eleven isostichs were obtained for strands L and H in unequal proportions. Each isostich fraction was subfractionated by base composition on DEAE-cellulose at pH 3.0. 61 Pyrimidine oligonucleotide clusters were separated from the H strand and only 46 from the L strand. The findings show a higher degree of asymmetry between the strands in the distribution of cytosine-rich clusters as compared with thymine-rich clusters. The longest cytosine oligodeoxynucleotide present in both strands is of chain length 5. There is an unusually high distribution of thymine oligodeoxynucleotides of length 5-11. Up to chain length 6, the distribution of thymine oligodeoxynucleotides between the strands is about equal; from chain length 7 to 11 they occur predominantly in the H strand.

Amines↗
PubMed1971

Asymmetric template function of microbial deoxyribonucleic acids: transcription of messenger ribonucleic acid.

In Bacillus subtilis and Escherichia coli, pulse-labeled ribonucleic acid (RNA) synthesized during step-down growth hybridized preferentially with the heavy (H) strand of methylated albumin-Kieselguhr-fractionated deoxyribonucleic acid (DNA). At high RNA inputs, the ratio of RNA hybridized with the H strand to that hybridized with the light (L) strand was 8.7 for B. subtilis and 2.0 for E. coli. At high DNA inputs, the H/L hybridization ratio increased by a factor of two. This change in the hybridization ratio was attributable to the fraction of the pulse-labeled RNA which is in stable RNA components. The hybridization peak of pulse-labeled RNA was specifically located in the late-eluting region of the absorbance profile of the H strand. This region was considered to represent the most actively transcribing H strand templates.

Bacillus subtilis↗
PubMed1970

Template properties of complementary fractions of denatured microbial deoxyribonucleic acids.

DNA preparations from seven bacterial species and from E. coli phage T4, and also the complementary L and H fractions into which these DNA specimens, after denaturation, were separated by chromatography on methylated albumin-kieselguhr columns, were studied as templates in the RNA polymerase system, and the nucleotide composition of the RNA products was determined. The RNA transcripts of the separated L and H fractions were found to be faithful copies of the respective DNA fractions. This suggests "transcription analysis" as a sensitive and reliable analytical technique for the determination of the base composition of denatured DNA. The L and H fractions of T4 DNA were shown, both by temperature-absorbance profiles and by transcription analysis, to be mutually complementary. The RNA products formed with intact DNA as the template were not exact copies of the latter; their composition indicated that under our experimental conditions the "heavy" DNA strand is transcribed preferentially.

Adenine↗
PubMed1970

Asymmetric template function of microbial deoxyribonucleic acids: transcription of ribosomal and soluble ribonucleic acids.

In Bacillus subtilis and Escherichia coli, 16 and 23S ribosomal ribonucleic acid (rRNA) hybridize exclusively with the heavy (H) strand of methylated albuminkieselguhr (MAK)-fractionated complementary deoxyribonucleic acid (DNA) strands. All the soluble RNA (4S RNA) in B. subtilis and 66 to 75% of the 4S RNA in E. coli also hybridize with the H strand. Interspecific hybridization shows that E. coli 23S rRNA also binds selectively to the DNA H strand of Salmonella typhimurium. The hybridization peak for all three cellular RNA components is specifically located in the late-eluting region of the absorbance profile of the DNA H strand. The early-eluting region of the light (L) strand preferentially inhibits the hybridization between the peak region of the H strand and 23S rRNA. These regions are considered to represent the transcribing sequences and their complements for 23S rRNA in the separated H and L strands of DNA, respectively.

Albumins↗
PubMed1969

Separation of microbial deoxyribonucleic acids into complementary strands.

DNA preparations from seven bacterial species and from the E. coli phage T4 can, after denaturation with alkali, be separated chromatographically into two distinct components (L and H) through intermittent gradient elution from methylated albumin kieselguhr columns. The direct chemical analysis of the L and H fractions isolated from DNA specimens of the AT type shows them to exhibit a high degree of complementarity; but despite a bias in the distribution of purines and pyrimidines, either fraction contains equimolar quantities of 6-amino and of 6-keto nucleotides. In the L and H components derived from DNA of the equimolar and GC types, the distribution bias appears limited to guanine and cytosine. It is suggested that the L and H fractions represent the complementary DNA strands.

Bacillus↗