Xanthomonas Pruni Research Articles

Temperature Effects on the Relationships Between Xanthomonas pruni and its Virulent Phages

Temperature Effects on the Relationships Between Xanthomonas pruni and its Virulent Phages

Bacterial Spot of Stone Fruit in Queensland

Bacterial spot, Xanthomonas pruni, is a serious disease of stone fruit in the Granite Belt district of south-eastern Queensland. The Queensland isolates of X. pruni correspond to those described from overseas.

Wound protection on deciduous fruit trees

Abstract After a number of antimicrobial compounds had been investigated, captafol and mercuric oxide were included singly or together in a compounded methyl methacrylate/octyl acrylate copolymer emulsion, and the preparations were compared for inhibition of spore germination or growth of Stereum purpureum (Pers.) Fr., Nectria galligena Bres., Pseudomonas syringae van Hall., and Xanthomonas pruni (Erw. Smith) Dowson, in vitro. Mercuric oxide inhibited the bacteria at lower concentrations than captafol, but captafol was more effective than mercuric oxide in inhibiting the fungi. In glasshouse and field tests the compounded acrylic emulsion containing 1% w/w captafol plus 1% w/w mercuric oxide, and the proprietary wound dressing Santar A, were highly effective in protecting wounds on peach seedlings, and on apple rootstocks, from infection by spores of S. purpureum. No phytotoxic reactions were observed with the former preparation, but under some conditions Santar A caused a delay in callus development, and stimulated gum exudation, in peach trees. The dressings also assisted the healing of wounds made when tissue infected by N. galligena was cut away from apple branches.

A comparative study of the regulation of nicotinamide-adenine dinucleotide biosynthesis

1. 1. The regulation of NAD biosynthesis was studied in Escherichia coli, Bacillus subtilis and Bacillus megaterium, bacteria which utilize conventional metabolites and an “aspartate-glycerol pathway” for NAD biosynthesis and Xanthomonas pruni, the only bacterium in which tryptophan is known to serve as a precursor to NAD. The recent findings that in bacteria quinolinic acid occurs via the aspartate-glycerol pathway, suggested the need for a more recent evaluation. 2. 2. The biosynthesis of quinolinic acid via the aspartate-glycerol pathway in E. coli is repressed when cells are grown in the presence of excessive levels of nicotinic acid. In addition, nicotinate phosphoribosyltransferase (EC 2.4.2.11), an enzyme on the ‘salvage pathway’ for NAD biosynthesis, is repressed by comparable levels of nicotinic acid. However, quinolinate phosphoribosyltransferase is unaffected under the same conditions of growth. In contrast, in B. subtilis and B. megaterium quinolinate phosphoribosyltransferase is repressed by growth on increased levels of nicotinic acid, but nicotinate phosphoribosyltransferase is not. 3. 3. None of the enzymes of the tryptophan-NAD pathway studied in Xanthomonas pruni was repressed by growth in the presence of excess nicotinic acid. However, feedback inhibition of tryptophan pyrrolase may offer a means for the regulation of NAD biosynthesis in this organism.

Biochemical Studies of the Host-Parasite Relationship between Xanthomonas oryzae and Rice Plant

1. The utilizations of inorganic sulfur sources in seven strains of Xanthomonas oryzae and other five species belong to Xanthomonas were investigated.2. Although sulfur containing amino acids were required for the rapid growth of seven strains of Xanthomonas oryzae and Xanthomonas citri, it was observed that these bacteria utilize inorganic sulfate after prolonged latent period which may require for adaptive formation of the sulfate reducing enzyme system.3. No marked difference in pathogenicity has been observed when the cells prepared with either the complete medium or the synthetic basal medium containing sodium sulfate were inoculated to rice plant leaves.4. No direct relationship between the ability of utilizing inorganic sulfate, requirement of sulfur containing amino acids and pathogenicity and/or lysotype on bacteriophage was observed in seven strains of Xanthomonas oryzae.5. Xanthomonas malvacearum, Xanthomonas phaseoli, Xanthomonas pruni and Xanthomonas vesicatoria utilized extensively inorganic sulfate as a sole sulfur source.6. The utilization of inorganic sulfate in Xanthomonas citri, Xanthomonas oryzae and Xanthomonas pruni were promoted by the presence of nicotinic acid amide in the medium.

Comparative aspects of some bacterial dehydrogenases and transhydrogenases.

Ragland, T. E. (Brandeis University, Waltham, Mass.), T. Kawasaki, and J. M. Lowenstein. Comparative aspects of some bacterial dehydrogenases and transhydrogenases. J. Bacteriol. 91:236-244. 1966.-Twenty-eight diverse bacterial species were surveyed for the activities and coenzyme specificities of four enzymes: isocitrate dehydrogenase (ICDH), glucose-6-phosphate dehydrogenase (G-6-PDH), 6-phosphogluconate dehydrogenase (6-PGDH), and reduced nicotinamide adenine dinucleotide phosphate-nicotinamide adenine dinucleotide (NAD) transhydrogenase (TH). Most of the species that exhibited a nicotinamide adenine dinucleotide phosphate (NADP)-linked ICDH also showed significant TH activity, but there were several which did not. Only one of the organisms tested, Xanthomonas pruni, had an ICDH active with both NAD and NADP; it was devoid of TH activity. Acetobacter suboxydans, which lacks ICDH altogether, also had no TH. Some of the species examined had G-6-PDH or 6-PGDH (or both) of dual coenzyme specificity, but there was no apparent relation between these findings and the presence or absence of TH. The TH reaction was assayed by use of analogues of NAD as acceptors. The bacteria could be divided into two groups on the basis of TH specificity, one group reacting at a much faster rate with the 3-acetylpyridine analogue of NAD than with the thionicotinamide analogue, whereas the converse was true for the other group. A few organisms showed no marked specificity for either analogue. This division of specificity can be related to the currently accepted taxonomic classification of the organisms, although a few apparent anomalies were found.

Proposed intermediary role of 3,4-dihydroxyanthranilic acid in the biosynthesis of nicotinic acid.

Summary3,4-dihydroxyanthranilic acid was not converted to quinolinic acid or nicotinic acid by rat or hog liver preparations. Spectrophotometric evidence indicates that this compound is not the transient intermediate formed in the conversion of 3-hydroxyanthranilic to quinolinic acid by liver enzymes. It was not utilized by Xantho-monas pruni for growth, or by the rat for growth or formation of urinary nicotinic acid or quinolinic acid.