Binding of aflatoxins B1 and G1 to human serum proteins

Zusammenfassung In vitro Experimente mit¹⁴C-markiertem, gereinigtem Aflatoxin zur Untersuchung der Bindung von Aflatoxin B₁ und G₁ an verschiedene Serumproteine ergaben, dass Aflatoxin B₁ hauptsächlich mit-Globulin, G₁ dagegen vorwiegend mit Albumin bindet.

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This work was supported by part by a grant from the China Medical Board of New York, Inc., and was performed during one of us (S.S.L.) received a class C. research award from the National Science Council, Republic of China.     

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.     

Effect of methylendioxyphenyl synergists on metabolism of carbaryl byAspergillus terreus

Zusammenfassung Die Methylendioxyphenyl-Synergisten Sesamex und Sesamol hemmen die Umwandlung des Insektizids Carbaryl (1-Naphthyl-N-Methylcarbamat) zu N-Hydroxymethylcarbamat und 1-Naphthylcarbamat beiAspergillus terreus. Die Wirkung der beiden Synergisten ist jedoch von begrenzter Dauer, da sie durch den Pilz metabolisiert werden.

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Authorized for publication on 10 July 1974 as paper number 4732 in the journal series of the Pennsylvania Agricultural Experiment Station.     

Production and characterization of antibodies cross-reactive with major aflatoxins

Antibodies cross-reactive with 4 major aflatoxins were demonstrated three weeks after immunization of rabbits with an immunogen which was prepared by conjugating aflatoxin B3 to bovine serum albumin. Aflatoxin B3 was first converted to its hemisuccinate before conjugation to the protein. Tritiated aflatoxin B1 (AFB1) was used as the marker ligand both for antibody titer determination as well as for analysis of antibody specificity. Competitive RIA revealed that the antibodies have good cross-reactivity with aflatoxins B1, B2, G1, and G2 when tritiated AFB1 was used as the marker ligand. The concentrations causing 50% inhibition of binding of 3H-AFB1 to the antibodies by unlabeled aflatoxins B1, B2, G1, G2 and B3 were found to be 0.25, 3.34, 0.32, 4.0 and 0.53 ng/assay, respectively. The antibodies could be used for simultaneous analysis of aflatoxins B1 and G1, two of the most important toxic metabolites produced by Aspergillus flavus and A. parasiticus.     

Production and characterization of antibodies cross-reactive with major aflatoxins

Antibodies cross-reactive with 4 major aflatoxins were demonstrated three weeks after immunization of rabbits with an immunogen which was prepared by conjugating aflatoxin B₃ to bovine serum albumin. Aflatoxin B₃ was first converted to its hemisuccinate before conjugation to the protein. Tritiated aflatoxin B₁ (AFB₁) was used as the marker ligand both for antibody titer determination as well as for analysis of antibody specificity. Competitive RIA revealed that the antibodies have good cross-reactivity with aflatoxins B₁, B₂, G₁, and G₂ when tritiated AFB₁ was used as the marker ligand. The concentrations causing 50% inhibition of binding of³H-AFB₁ to the antibodies by unlabeled aflatoxins B₁, B₂, G₁, G₂ and B₃ were found to be 0.25, 3.34, 0.32, 4.0 and 0.53 ng/assay, respectively. The antibodies could be used for simultaneous analysis of aflatoxins B₁ and G₁, two of the most important toxic metabolites produced byAspergillus flavus andA. parasiticus.     

Sclerotial and low aflatoxigenic morphological variants from haploid and diploidAspergillus parasiticus

Summary Serial transfer of mycelial macerates of a wild type, haploid, aflatoxigenic strain ofAspergillus parasiticus in a defined liquid medium resulted in the production of three new morphological classes: a sclerotial form with high aflatoxin production, and two variant forms (fan andfluff) with lowered sporulation, no sclerotia, and attenuated levels of aflatoxin. A genetically marked diploid containing mutant markers for aflatoxin pathway intermediates yielded the same three morphological classes upon serial transfer of macerated mycelia. When these diploid variants were treated with a haploidization agent, and the phenotypes of the resultant segregants scored, a low frequency of colonies producing aflatoxin pathway intermediates was recovered. These genetic data indicate that the structural genes for the aflatoxin pathway are present but somehow attenuated in thefan andfluff strains.This work was supported by a Cooperative Agreement from the U.S. Department of Agriculture, (58-7B30-3-556).     

Biosynthesis of aflatoxins by cell-free preparations fromAspergillus flavus

Résumé Incorporation d'acétate-1-¹⁴C, de leucine-U-¹⁴C et de mévalonate-2-¹⁴C sous forme d'aflatoxine dans les extraits libres des cellulesd'Aspergillus flavus. Dans le cas du mévalonate, l'incorporation de l'ordre de 0,4 pour 100 et les activités spécifiques sont 13 000 à 40 000 cpm/mg d'aflatoxine. La capacité d'incorporation des substrats en aflatoxine s'observe, en particulier, dans les mitochondries.     

Genetic control over the duration of G1 phase

or fi y G₁ , .     

Fungistatic action of aflatoxin B1

Résumé La croissance des plusieurs espèces d'Aspergillus et dePenicillium dans un milieu modifié de Czapek a été inhibitée par l'aflatoxin B₁. Cet arrêt de croissance pourrait être annulé en substituant au nitrate de sodium un extrait de levure comme source d'azote.

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This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U.S. Department of Agriculture.     

Cell fate determination during G1 phase progression

During the cell cycle, a cell may encounter one of five different fates: it can proliferate, differentiate, become quiescent or senescent, or go into apoptosis. The initiation of such fates is often seen in the G1 phase. The aim of this review is to describe an integrative model of G1 phase progression and cell fate determination. Along the G1 phase, the cell will encounter an early checkpoint after which apoptosis can result. For a quiescent state and for differentiation, the cell will exit G1 before the restriction point and a subsequent differentiation checkpoint will decide the fate of the cell, quiescence or differentiation. After the restriction point, the cell can be arrested in response to stress stimuli, such as telomere depletion, and a decision between senescence and apoptosis occurs. Received 19 June 2007; received after revision 23 July 2007; accepted 17 August 2007     

G1-phase progression in pluripotent stem cells

Cellular and Molecular Life Sciences - During early embryonic development both the rapid increase in cell number and the expression of genes that control developmental decisions are tightly...     

Resolution of small G1 and G2 populations of L1210 leukemia by flow microfluorometric analysis aided by velocity sedimentation

Summary L1210 leukemic cells grown in vitro were subjected to kinetic analysis using a flow microfluorometer. A single broad peak was found for the DNA content distribution if unfractionated cells were used; prior fractionation using lg velocity sedimentation allowed the separation of small peaks with smaller (G₁) and larger (G₂) DNA contents from the dominant S phase peak with intermediate DNA content.This work was supported by grant number 5P01CA13053 awarded by the National Cancer Institute, DHEW USA, and by grant num ber RBI 76-1 from the Queen Wilhelmina Fund, The Netherlands.     

Resolution of small G1 and G2 populations of L1210 leukemia by flow microfluorometric analysis aided by velocity sedimentation

L1210 leukemic cells grown in vitro were subjected to kinetic analysis using a flow microfluorometer. A single broad peak was found for the DNA content distribution if unfractionated cells were used; prior fractionation using lg velocity sedimentation allowed the separation of small peaks with smaller (G1) and larger (G2) DNA contents from the dominant S phase peak with intermediate DNA content.