Two hundred and nine strains of Pseudomonas solanacearum were obtained from potato fields in Nagasaki, Japan, at periodic intervals late in the growing season on the fall crop. Thirty seven strains were classified as biovar II, one as biovar III, and 171 as biovar IV. The percentage of biovar II strains increased in the latter period of the growing season. In static culture at 16.5C, biovar II strains grew more rapidly than those of biovar IV. Biovar IV grew more at 35C for four days than at 24C for seven days and 16.5C for 14 days. However, biovar II did not show clear difference of growth at 16.5C for 14 days and 35C for four days. There was no difference in the latent period between biovar II and IV strains in inoculation experiments. Biovar II and IV strains were considered to be race 3 and race 1, respectively. This is the first report of race 3 of P. solanacearum in Japan.

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The 3-keto derivatives of trehalose and sucrose respectively were prepared by a one-step enzymatic route using D-glucoside 3-dehydrogenasefrom Flavobacterium saccharophilum. Reductive aminationof 3-ketotrehalose with ammonium acetate and sodiumcyanoboro- This enzyme converts some hexopyranosides to the corresponding 3-keto compounds1"^. The purification and characterization of this enzyme was reported by some researchers5~7). However, the D-glucoside 3-dehydrogenase of A. tumefaciens is an inducible enzyme and its activity rapidly decays on cessation of growth on cultivation. This feature limits the application of the bacteria as biosynthetic agents. Werecently found the D-glucoside 3-dehydrogenase in Flavobacterium saccharophilum which is involved in the degradation of the antifungal agents, validamycins, as the trigger enzyme in the C-N bond cleavage of validoxylamine A8~10). The D-glucoside 3-dehydrogenase in F. saccharophilum is a constitutive enzyme and approximately 80 % of its activity is contained in the membranefraction of this organism. This paper describes the preparation of 3-ketotrehalose and 3-ketosucrose using a membrane fraction of F. saccharophilum, the reductive amination of these keto compoundswith ammonium acetate and sodium cyanoborohydride, and the catalytic hydrogenation of the oximes obtained from the keto compounds. The antibiotic and glycohydrolase inhibitory activities of the 3-amino-3-deoxy disaccharides are also reported.Preparation of 3-Ketotrehalose and 3-Ketosucrose 3-Ketotrehalose and 3-ketosucrose were prepared by the one-step enzymatic route using a membrane fraction of F. saccharophilum. The resulting incubation mixture of a substrate (1 g) and a membranefraction was centrifuged and the supernatant was applied to a column of activated carbon and eluted with 50%MeOH. The concentrate of the eluate was then applied to a column of Dowex 50W-X8(Ca2+). The column was developed with water to give 3-ketotrehalose (550 mg) or 3-ketosucrose (470 mg). The structure of the 3-keto compounds were confirmed by 1H and 13C NMRdata.

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A survey of Potato virus Y (PVY) was carried out on weeds growing in and around potato fields in Syria during the autumn growing seasons of 2002, 2004 and 2006. A total of 59 samples of eight weed species and three tobacco (Nicotiana tabacum) samples were tested by ELISA using PVY antisera. Among them 15 samples belonged to Solanum nigrum (7 samples), Physalis sp. (6 samples) and tobacco (2 samples) were PVY infected. This suggests that weed hosts and neighbouring tobacco fields are natural reservoirs of PVY in Syria. According to their biological, serological and molecular characteristics, the majority of weed PVY isolates belonged to the PVYSYR variant indicating a possible correlation between the high incidence of PVYSYR in potato and weed hosts. This is the first report on the occurrence and characterization of weed PVY isolates from Syria.