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R Hütter

Publications and source records attributed to R Hütter.

At least 55 records · Page 3Linked to original sources
PubMed1984

Streptomycin-sensitivity in Streptomyces glaucescens is due to deletions comprising the structural gene coding for a specific phosphotransferase.

The wild type strain of Streptomyces glaucescens produces hydroxystreptomycin and has a natural resistance towards the streptomycin group aminoglycoside antibiotics. The inherent resistance is a genetically unstable character and mutant strains sensitive to streptomycins arise spontaneously at unusually high frequencies. The gene conferring streptomycin resistance was cloned and characterised as a streptomycin specific phosphotransferase. Hybridisation experiments show that the mutational event leading to sensitivity is due to large deletions, most likely on the chromosome, comprehending the structural gene coding for a streptomycin phosphotransferase and its flanking regions. Interspecific expression of the S. glaucescens phosphotransferase was found in Streptomyces lividans as well as in Escherichia coli.

Chromosome Deletion↗
PubMed1984

2-Chloro-4-amino-1,3,5-triazine-6(5H)-one: a new intermediate in the biodegradation of chlorinated s-triazines.

Pseudomonas sp. strain A grew with 2-chloro-1,3,5-triazine-4,6-diamine as the sole and growth-limiting source of nitrogen. The substrate was utilized quantitatively and concomitantly with growth and with excretion of a product which was identified as 2-chloro-4-amino-1,3,5-triazine-6(5H)-one. The reaction yielded 1 mol of organic product and 1 mol of NH4+ per mol of substrate.

Biodegradation, Environmental↗
PubMed1984

Tyrosinase activity in Streptomyces glaucescens is controlled by three chromosomal loci.

In Streptomyces glaucescens the production of the enzyme tyrosinase (EC 1.14.18.1) is controlled by at least three loci: MELA, MELB, and MELC. Mutations in MELA and MELB are rare. They both map on the S. glaucescens chromosome in the interval between the markers leu-2 and ura-3. MELC, however, shows an exceptionally high mutation rate. MelC strains arise spontaneously with a frequency of about 0.1%, and they can be specifically induced with ethidium bromide, acridine orange, or by prolonged storage of spores or mycelium at 4 degrees C. Ultraviolet (UV) irradiation or treatment with N-methyl-N'-nitro-N-nitrosoguanidine under conditions which induce auxotrophic mutations, however, do not specifically induce the appearance of tyrosinase-negative strains. Most, but not all, of the melC strains acquire additional mutations which make them sensitive to streptomycin (strS) and unable to produce hydroxystreptomycin. Mapping of the mutations classified as melC proves to be difficult. Some of the matings indicate a map position between his-2 and pro-1, while others, all highly unbalanced crosses, can not be analyzed in a meaningful way because of abnormal segregation of the reference markers. This is probably due to some of the additional mutations which occur frequently with the melC mutations and not to extrachromosomal inheritance of MELC.

Alleles↗
PubMed1983

Biochemical pathways and mechanisms nitrogen, amino acid, and carbon metabolism.

For both nitrogen and carbon metabolism there exist specific regulatory mechanisms to enable cells to assimilate a wide variety of nitrogen and carbon sources. Superimposed are regulatory circuits, the so called nitrogen and carbon catabolite regulation, to allow for selective use of "rich" sources first and "poor" sources later. Evidence points to the importance of specific regulatory mechanisms for short term adaptations, while generalized control circuits are used for long term modulation of nitrogen and carbon metabolism. Similarly a variety of regulatory mechanisms operate in amino acid metabolism. Modulation of enzyme activity and modulation of enzyme levels are the outstanding regulatory mechanisms. In prokaryotes, attenuation and repressor/operator control are predominant, besides a so called "metabolic control" which integrates amino acid metabolism into the overall nutritional status of the cells. In eukaryotic cells compartmentation of amino acid metabolites as well as of part of the pathways becomes an additional regulatory factor; pathway specific controls seem to be rare, but a complex regulatory network, the "general control of amino acid biosynthesis", coordinates the synthesis of enzymes of a number of amino acid biosynthetic pathways.

Journal Article↗
PubMed1983

Qualitative analysis of waste-water from ametryne production.

s-Triazines in waste-water from the synthesis of ametryne (2-(ethylamino)-4-[(l-methylethyl) amino]-6-(methylthio)-1,3,5-triazine) were tentatively identified co-chromatographically by HPLC and by UV-spectra. Alkylated s-triazines (e.g. hydroxyametryne, 4-(ethylamino)-6-(methylthio)-1,3,5-triazine-2(1H)-one, and N-ethylammelide) were isolated by preparative chromatography on a reversed phase support, and were identified by mass spectrometry. Putative cyanuric acid was desalted on activated charcoal and its identity confirmed as the silylated derivative by GLC.

Herbicides↗
PubMed1983

Chromosomal instability in Streptomyces glaucescens: mapping of streptomycin-sensitive mutants.

Streptomyces glaucescens strain GLAO (=ETH 22794) produces hydroxystreptomycin and has a high natural resistance to hydroxystreptomycin, dihydrostreptomycin and streptomycin. The wild-type strain gives rise spontaneously to streptomycin-sensitive (StrS-) variants at a frequency of 0 . 2 to 1 . 4%. These mutants lack streptomycin phosphotransferase activity responsible for the wild-type resistance to streptomycin group antibiotics and are unable to produce detectable amounts of hydroxystreptomycin. Mapping experiments showed that the strS marker lies between the chromosomal markers lys-2 and ura-3 on the linkage map of S. glaucescens. The molecular basis for instability of this marker is as yet unknown.

Alleles↗
PubMed1983

Hydroxystreptomycin production and resistance in Streptomyces glaucescens.

The wild-type strain of Streptomyces glaucescens produces hydroxystreptomycin and shows an inherent natural resistance to streptomycin group aminoglycoside antibiotics. Cell free extracts of the wild-type strain were able to inactivate streptomycin, hydroxystreptomycin and dihydrostreptomycin in the presence of ATP. The phosphotransferase did not inactivate other aminoglycoside antibiotics, including spectinomycin. Mutant strains were isolated, which were highly sensitive to streptomycin group aminoglycosides, had no measurable phosphotransferase activity and were unable to form detectable amounts of hydroxystreptomycin. This suggests either a correlation between phosphotransferase activity, streptomycin resistance and hydroxystreptomycin formation or defects in more than one gene in the strS mutant strains tested.

Anti-Bacterial Agents↗
PubMed1982

The degradative pathway of the s-triazine melamine. The steps to ring cleavage.

1. The degradative pathway of melamine (1,3,5-triazine-2,4,6-triamine) was examined in Pseudomonas sp. strain A. 2. The bacterium grew with melamine, ammeline, ammelide, cyanuric acid or NH+4 as sole source of nitrogen, and each substrate was entirely metabolized. Utilization of ammeline, ammelide, cyanuric acid or NH+4 was concomitant with growth. But with melamine as substrate, a transient intermediate was detected, which was identified as ammeline by three methods. 3. Enzymes from strain A were separated by chromatography on DEAE-cellulose, and four activities were examined. 4. Melamine was converted stoichiometrically into equimolar amounts of ammeline and NH+4. 5. Ammeline was converted stoichiometrically into equimolar amounts of ammelide and NH+4; ammelide was identified by four methods. 6. Ammelide was converted stoichiometrically into equimolar amounts of cyanuric acid and NH+4; cyanuric acid was identified by four methods. 7. Cyanuric acid was converted by an enzyme preparation into an unidentified product with negligible release of NH+4. 8. The specific activities of the degradative enzymes (greater than or equal to 0.3 mkat/kg of protein) were high enough to explain the growth rate of the organism. 9. The bacterium converted 0.4 mM-melamine anaerobically into 2.3 mM-NH+4. 10. Two other pseudomonads and two strains of Klebsiella pneumoniae were also examined, with similar results. 11. The degradative pathway of melamine appears to be hydrolytic, and proceeds by three successive deaminations to cyanuric acid, which is further metabolized.

Chemical Phenomena↗
PubMed1982

Accumulation of 2'-O-methylguanosine deficient tRNATrp in tryptophan limited Saccharomyces cerevisiae.

Saccharomyces cerevisiae synthesizes one major tryptophan transfer ribonucleic acid (tRNATrp) species (isoacceptor A) carrying characteristic base modifications. Under tryptophan limited growth conditions wild-type strain X2180-1A exhibited a second important tRNATrp species (isoacceptor B). The total amount of tRNATrp, approximately 2.5 pmol (mg dry wt)-1, stayed essentially constant during amino acid shift-down experiments. The amount of isoacceptor B relative to total tRNATrp was 10 to 15% during amino acid sufficient exponential growth conditions, but increased during tryptophan limitation three- to four-fold. Analysis of the base compositions showed that isoacceptor B differed from isoacceptor A in one respect only: 2'-O-methylguanosine, a modified guanosine base occurring at position 17 of the major isoacceptor A tRNATrp, was not detectable in hydrolysates of purified isoacceptor B. The biological significance of isoacceptor B is discussed.

Guanosine↗
PubMed1982

Secretion of tyrosinase in Streptomyces glaucescens.

In Streptomyces glaucescens, the intracellular and the extracellular enzyme forms of tyrosinase were found to be indentical in molecular weight (29 000), in copper content (0.21%), in the 19 amino acids at the amino-terminal end and in the ratio of cresolase to catecholase activity (0,005). The tyrosinase secretion process exhibited a constant rate of 0.15 units h-1 (mg protein)-1. Under highly induced conditions intracellular tyrosinase was accumulated. Mutations responsible for the non-melanogenic, tyrosinase-positive non-secretor mutant type are located chromosomally on the upper right arc of the S. glaucescens map near the ade-1 marker.

Catechol Oxidase↗
PubMed1982

Ametryne and prometryne as sulfur sources for bacteria.

Bacteria were isolated that could utilize quantitatively the s-triazine herbicide prometryne [N,N' -bis(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine] or ametryne [N-ethyl-N'-(1-methylethyl)-6-(methylthio)-1,3,5-triazine- 2,4-diamine], or both, as a sole source of sulfur for growth. The success of enrichments depended on previous exposure of the soil inoculum to s-triazine herbicides. Deaminoethylametryne [4-(1-methylethyl)amino-6-(methylthio)-1,3,5-triazine-2-(1H)-one], methylsulfonic acid, and sodium sulfate could also be used as sulfur sources. Utilization of a compound was quantified as the growth yield per mole of sulfur supplied. Yields were about 6 kg of protein per mol of sulfur. The product of the desulfuration of an s-triazine was identified as the corresponding hydroxy-derivative. This is the first substantiated report of the utilization of these s-triazines as sulfur sources by bacteria.

Journal Article↗