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H Küntzel

Publications and source records attributed to H Küntzel.

At least 55 records · Page 3Linked to original sources
PubMed1977

Further studies on ASN-136 and monoketo-organomycin cystaurimycin, a broad spectrum substance produced by partial enzymic digestion of monoketo-organomycin.

The two antibiotics ASN-136 and monoketo-organomycin (MKOM) showed very close similarities in their UV, IR spectra and elemental analysis to those of tuberactinomycin and yazumycin respectively. Further chemical and enzymic studies revealed the novelty of the two former antibiotics. Partial enzymic hydrolysis of MKOM yielded a hydrolytic product of more potent inhibitory action compared with the parent antibiotic. Having cystine as the N-terminus and taurine as the C-terminus in its molecule, this enzymic degradation product was designated cystaurimycin. Performic acid oxidation of MKOM and of cystaurimycin improved their growth inhibitory effects on the test organisms used.

Amino Acids↗
PubMed1976

Physical map of Neurospora crassa mitochondrial DNA and its transcription unit for ribosomal RNA.

A circular denaturation and restriction map of mitochondrial DNA from Neurospora crassa is presented. The map shows the position of all twelve fragments produced by restriction endonuclease Eco R I and the position of the largest Hin III fragment along the previously established map of AT-rich sequences. The two wild type strains Em 5256 and 7A differ in the lengths of two Eco R I fragments. No difference was found between the mitochondrial mutant "poky" and its parent strain. The position of the DNA segment carrying the transcription unit for the two ribosomal RNA molecules has been determined by molecular hybridization.

Chromosome Mapping↗
PubMed1975

Denaturation map of the circular mitochondrial genome of Neurospora crassa.

A denaturation map of mitochondrial DNA from the wild type strain 5256 of Neurospora crassa was constructed by computer analysis of the contour length distribution of single- and double-stranded regions of nineteen circular and three full length linear molecules after partial denaturation. The data suggest that mitochondrial DNA in this strain is a homogeneous population of a circular molecule of molecular weight 41 - 10(6) with an asymmetric distribution of AT-rich regions, and that linear molecules derive from this genome by random breaks during isolation.

Computers↗
PubMed1975

Lipophilic proteins encoded by mitochondrial and nuclear genes in Neurospora crassa.

Mitochondrial proteins soluble in neutral chloroform-methanol (2:1) were separated from lipids by ether precipitation and resolved by Sephadex G-200 filtration in the presence of dodecylsulfate into two major fractions eluting in the excluded region (peak I) and in a region of an apparent molecular weight 8000 (peak II). Residual phospholipids are found only in peak II. Peak I consists of several aggregated small polypeptides of molecular weights around 8000, which can be disaggregated by mild oxidation with performic acid. Cycloheximide stimulates almost two-fold incorporation of radioactive phenylalanine into peak I proteins but inhibits labelling of peak II proteins by 95%. Chloramphenicol and ethidium bromide inhibit the synthesis of peak I proteins by 70% and 95% respectively, but do not affect labelling of peak II proteins. At least 30% of the translation products of mitochondrial DNA in vitro behave like peak I proteins: they are soluble in organic solvents, they aggregate in dodecylsulfate buffer after removal of phospholipids and they contain species of molecular weights around 8000 that disaggregate upon oxidation. The data strongly suggest that the proteins of peak I are encoded by mitochondrial genes and synthesized on mitochondrial ribosomes, whereas the proteins of peak II are encoded by nuclear genes and synthesized on cytoplasmic ribosomes. Both groups of lipophilic proteins are very similar in their molecular weights, but the mitochondrially coded peak I proteins have the unique property of forming large heat-stable aggregates in the presence of dodecylsulfate.

Cell Nucleus↗
PubMed1973

Virus-like particles in an estranuclear mutant of Neurospora crassa.

A particulate fraction not present in wild-type cells has been isolated from the cytoplasm and from lysed mitochondria of the respiratory-deficient extranuclear mutant "abnormal-1" of Neurospora crassa. The particles have a density between 1.13 and 1.2 g/ml. They appear in thin sections after OsO(4) fixation as virus-like polymorphic vesicles containing an electron-dense nucleoid of 120-170 nm in diameter. The central core is surrounded by one or two "unit membrane" envelopes of 100 A thickness. The particles contain a single-stranded 33S RNA that is converted to 7-9S RNA by heat treatment in the presence of sodium dodecyl sulfate and that differs in its base composition from mitochondrial and cytoplasmic ribosomal RNA. They contain 7% phospholipids rich in phosphatidylethanolamine and two major proteins, a lipoprotein of molecular weight 15,000 and a glycoprotein of molecular weight 95,000. It is suggested that these virus-like particles originate within mitochondria.

Centrifugation, Density Gradient↗
PubMed1972

Cooperation of mitochondrial and nuclear genes specifying the mitochondrial genetic apparatus in Neurospora crassa.

Enzymes involved in the expression of the mitochondrial genome in Neurospora crassa are induced by chloramphenicol and ethidium bromide, which block transcription and translation of mitochondrial DNA. It is concluded that most, if not all, proteins of the mitochondrial genetic apparatus are coded by nuclear genes, synthesized on cytoplasmic ribosomes, and controlled by a repressor-like mitochondrial gene product. A model explaining the coordination of nuclear and mitochondrial division cycles by repressor control is discussed.

Cell Nucleus↗