Franklyn G. Healy

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Four Streptomyces species have been described as the causal agents of scab disease, which affects economically important root and tuber crops worldwide. These species produce a family of cyclic dipeptides, the thaxtomins, which alone mimic disease symptomatology. Structural considerations suggest that thaxtomins are synthesized non-ribosomally. Degenerate(More)
Escherichia coli mutants with defined mutations in specific mod genes that affect molybdate transport were isolated and analyzed for the effects of particular mutations on the regulation of the mod operon as well as the fdhF and hyc operons which code for the components of the formate hydrogenlyase (FHL) complex. phi (hyc'-'lacZ+) mod double mutants(More)
During anaerobic growth of bacteria, organic intermediates of metabolism, such as pyruvate or its derivatives, serve as electron acceptors to maintain the overall redox balance. Under these conditions, the ATP needed for cell growth is derived from substrate-level phosphorylation. In Escherichia coli, conversion of glucose to pyruvate yields 2 net ATPs,(More)
The modABC gene products constitute the molybdate-specific transport system in Escherichia coli. Another operon coding for two proteins which diverges from the modABCD operon has been identified. The first gene of this operon codes for a 262-amino-acid protein, designated ModE (28 kDa), and the second genes codes for a 490-amino-acid protein. ModF (54 kDa).(More)
Streptomycetes are common soil inhabitants, yet few described species are plant pathogens. While the pathogenicity mechanisms remain unclear, previous work identified a gene, nec1, which encodes a putative pathogenicity or virulence factor. nec1 and a neighboring transposase pseudogene, ORFtnp, are conserved among unrelated plant pathogens and absent from(More)
The biosynthesis of the thaxtomin cyclic dipeptide phytotoxins proceeds nonribosomally via the thiotemplate mechanism. Acyladenylation, thioesterification, N-methylation, and cyclization of two amino acid substrates are catalyzed by the txtAB-encoded thaxtomin synthetase. Nucleotide sequence analysis of the region 3' of txtAB in Streptomyces acidiscabies(More)
A L-methionine-D,L-sulfoximine-resistant mutant of the cyanobacterium Anabaena variabilis, strain SA1, excreted the ammonium ion generated from N2 reduction. In order to determine the biochemical basis for the NH4 +-excretion phenotype, glutamine synthetase (GS) was purified from both the parent strain SA0 and from the mutant. GS from strain SA0 (SA0-GS)(More)
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