RESUMO
A gene was cloned from Actinobacillus pleuropneumoniae strain 4074 by complementation of an aroD strain of Escherichia coli. The E. coli gene aroD codes for a 3-dehydroquinase enzyme of type I, active in the aromatic biosynthesis pathway. The A. pleuropneumoniae gene, termed aroQ, displays no base or amino acid sequence homology to aroD of E. coli. It is instead homologous to the QUTE and qa-2 genes, respectively of Aspergillus nidulans and Neurospora crassa. These genes code for 3-dehydroquinase enzymes of type II, involved in the catabolism of quinic acid. The 1.8 kb fragment, which includes aroQ, carries four overlapping or adjacent open reading frames: a dapD gene; aroQ; one without homology to sequences in GenBank; and one with homology to the C-terminal 40% of chIN of E. coli.
Assuntos
Actinobacillus pleuropneumoniae/enzimologia , Actinobacillus pleuropneumoniae/genética , Aspergillus nidulans/genética , Genes Bacterianos , Hidroliases/genética , Neurospora crassa/genética , Sequência de Aminoácidos , Aspergillus nidulans/enzimologia , Sequência de Bases , Clonagem Molecular , Escherichia coli , Genes Fúngicos , Teste de Complementação Genética , Hidroliases/biossíntese , Dados de Sequência Molecular , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/genética , Neurospora crassa/enzimologia , Fases de Leitura Aberta , Plasmídeos , Mapeamento por Restrição , Salmonella typhimurium/enzimologia , Salmonella typhimurium/genética , Homologia de Sequência de Aminoácidos , Shigella flexneri/enzimologia , Shigella flexneri/genética , Especificidade da EspécieRESUMO
We have cloned and sequenced the gene (ARF) encoding the ADP-ribosylation factor (ARF) of Candida albicans. The gene contains an open reading frame of 537 nucleotides (nt) that codes for a protein with an Mr of 20,259. The C. albicans ARF gene is 67-70% identical at the nt level to other ARF sequences including those of humans; the deduced amino acid sequence of C. albicans ARF shows a 78-83% identity and 89-92% similarity to the other ARFs. Southern analysis of C. albicans genomic DNA suggested the presence of a second ARF gene. The presence of multiple ARF genes is a consistent finding among the other organisms previously shown to have ARFs.
Assuntos
Adenilil Ciclases/genética , Candida albicans/genética , Proteínas de Ligação ao GTP/genética , Genes Fúngicos , Fatores de Ribosilação do ADP , Sequência de Aminoácidos , Animais , Sequência de Bases , Southern Blotting , Candida albicans/enzimologia , Proteínas de Transporte/genética , Bovinos , Clonagem Molecular , Humanos , Dados de Sequência MolecularRESUMO
The radiation-resistant free-living nematode Panagrellus redivivus was used to study mutation rates in oocytes, following gamma, proton and neutron irradiation in the dose range 45-225 grays. gamma-Radiation produced approximately 0.001 lethal X-chromosomes per gray over the range tested. Proton or neutron irradiation produced approximately 0.003 lethal X-chromosomes per gray at lower doses, with the mutation rate dropping to 0.001 lethal X-chromosome per gray at the higher doses. These results suggest a dose-dependent mutation-repair system. Cell lethality was also examined. gamma-Radiation produced the greatest amount of cell lethality at all doses, while neutron irradiation had no cell lethal effect at any of the doses examined.