Partial complementation inAspergillus niger heterocaryon

Zusammenfassung Erzwungene Heterokaryen-Vereinigung zwischen Hypoxanthin und Histidin abhängiger Mutanten vonAspergillus niger, die auf minimalem Nährboden ohne Sporenproduktion wachsen. Das Phänomen wird als teilweise Ergänzung bezeichnet und als Gleichgewichtsstörung der Kerntypen im Heterokaryen oder als Verdünnungseffekt eines Genproduktes zweiter Ordnung im Zytoplasma gedeutet.     

Some comparative studies of two alkaline phosphatases fromAspergillus niger

Summary Alkaline phosphatases (ALP I and ALP II), isolated and purified fromAspergillus niger exhibited broad specificity towards a wide variety of substrates, and consistently ALP II was more active than ALP I. It is possible that the difference in levels of activity of the 2 enzymes may be of physiological importance in the mycelia ofA. niger.     

Nicotinic acid suppressors inAspergillus nidulans

Zusammenfassung Neun Suppressoren des Mutantennic 8 vonAspergillus nidulans wurden in der Kopplungsgruppe VII der Chromosomenkarte lokalisiert und unter verschiedenen Aspekten studiert. Eine Hypothese über die Mechanik der genetischen Regulierung der Erzeugung der Nikotinsäure wurde formuliert.     

Chloral hydrate induced haploidization inAspergillus nidulans

Summary This is the first report of induction of haploidization inAspergillus nidulans by chloral hydrate, which is an efficient polyploidizing agent for higher plants and a psychotropic drug for man. A new procedure has been described to isolate haploids from diploids with a very high frequency, as compared top-fluorophenylalanine, which is generally used for this purpose.     

Regulation of ammonia uptake inAspergillus nidulans

Summary The ammonia uptake inA. nidulans was found to be linear for about 20 min, and was proportional up to 1.5 mg/ml dry cell density. The transport of ammonia does not involve energy. Normal and biotin deficientA. nidulans showed an identical K_m-values of 10.26×10^–5 M ammonia for uptake. The uptake of ammonium ion has been shown to be regulated by the intracellular concentration of ammonia.Acknowledgment. The award of research fellowship by the Govt of India, Department of Atomic Energy, Bombay, to JDD is acknowledged.     

Induced production of cleistothecia inAspergillus unguis

Résumé SynonymieAspergillus unguis etA. nidulans basée sur l'obtention de périthèces chezA. unguis.     

Resistance to ethidium bromide inAspergillus nidulans

Summary A mutant ofAspergillus nidulans resistant to ethidium bromide was isolated and the semi-dominant gene responsible for this resistance was allocated on linkage group II at 17.42±3.05 units of recombination from thewA₃ gene. The gene also confers cross-resistance to acriflavin, malachite green and crystal violet. It was also shown that riboflavin is antagonistic to the toxic effect of ethidium bromide, at certain concentrations. The mechanisms which could be responsible for the toxic effect of this drug are discussed and compared with those of acriflavin. The use of theEtb ₁ gene in genetical analysis through the parasexual cycle is suggested.Acknowledgements. The authors are thankful to the National Council for the Development of Science and Technology (CNPq) for financial support through PIG-SIP 04/053 FAPESP.     

Biotin and fatty acid biogenesis inAspergillus flavus

Zusammenfassung Avidin vermindert die Biosynthese von Fettsäuren inAspergillus flavus, die nur von Biotin überwunden wird. Ähnliche Phänomene werden in anderen Pilzen gefunden.     

Induced morphogenetic variations inAspergillus oryzae by 8-azaguanine

Résumé Proliférations de l'appareil sporifère d'Aspergillus oryzae traité à l'azaguanine.

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The authors are deeply indebted to Dr.O. Isler of F. Hoffmann-La Roche, Basel (Switzerland) for his generous gift of 8-azaguanine and 6-azauracil. They are also grateful to the University Grants Commission, at New Delhi, which financed this research programme by grant-in-aid No. F-8/5-63 (G), to R.K.K.     

Genetic and allied effects of certain esters of inorganic acids inAspergillus nidulans

Resumen Fueron investigados los efectos mutagénicos de cinco esteres de acidos inorgánicos sobre el mutante bi^–1; meth^–1 delAspergillus nidulans. El método empleado fué el teste de retrocruzamiento con algunas variaciones. El dimetil sulfato se ha mostrado como el mas poderoso mutagénico, seguido por el di-etil sulfato. El mecanismo de induccion mutacional fue discutido y se estableció una hipótesis para explicarla.     

Degradation of chlorobenzoates byAspergillus niger

Summary InA. niger, the degradation of chlorobenzoates follows the protocatechuate branch of ß-ketoadipate pathway and the elimination of chloride takes place in the first hydroxylation step prior to ring cleavage.Acknowledgment. We wish to thank B.V. Kamath and Prof. Y.K. Agrawal for their help and advice in completing this investigation.     

Radiation-induced hyperdiploidy inHyoscyamus niger L

Summary A hyperdiploid plant type, approaching the triploid chromosome number, and representing possibly a high level of tetrasomy, was recorded in the progeny of a gamma ray-induced unbranched desynaptic mutant in the M₄ generation. Its meiotic behavior and its possible importance for deriving diverse hyperdiploid lines from desynaptic mutants are outlined.Acknowledgment. We are grateful to Dr Akhtar Hussian, Director, CIMAP, for his keen interest in the study and for providing the facilities.     

A new strain ofAspergillus niger producing citric acid

Zusammenfassung Durch Behandlung eines Zitronensäure produzierenden Stammes vonAspergillus niger mit-Strahlen, N-Lost und UV-Strahlen konnte die Zitronensäureausbeute um ungefähr das Vierfache gesteigert werden.     

Lipid accumulation by a cellulolytic strain ofAspergillus niger

Lipid accumulation by a cellulolytic mold,Aspergillus niger, was studied. The amount of lipid accumulated ranged from 13.6–16.6% on various carbon sources, namely glucose, xylose, avicel (microcrystalline cellulose) and bagasse (a natural lignocellulosic substrate). Neutral lipids, phospholipids and glycolipids of the mycelia varied from 41.0–46.2%, 34.9–38.4% and 18.7–22.6% of total lipids, respectively. Unsaturated fatty acids comprised around 80% of total fatty materials with linoleic and oleic acid predominating. Of the four nitrogen sources tested, NH₄Cl was the best source for lipid synthesis from cellulose (bagasse). Optimum temperature range for growth and lipid synthesis was 25–30°C.     

Abnormal development of phialides in a strain ofAspergillus niger

Summary AnAspergillus niger mutant strain (hpp) produces an average of 4.1% of conidiophores with phialide proliferations. Increased frequency of proliferations could be induced on all studied strains by growth on potato dextrose agar. The characteristic is recessive and seems to be due to a pleiotropic effect of the mutation for olive conidia color.Acknowledgments. The authors are indebted to CNPq for financial assistance provided with grant PIG/SIP 04/053 as well as the scholarships Pesquisador Científico (R.B.Jr) and Iniciação Científica and Aperfeiçoamento (G.U.V.).     

Sulla biochimica della fermentazione citrica da parte dell'Aspergillus niger

Summary In a strain ofAsp. niger grown inBernhauer medium, succinic-dehydrogenase activity decreased and asparticglutamic transaminase activity remained practically constant, while citric acid accumulated in the medium.