Synthesis and quarternization of 6-(substitutedamino)-purines with antitumor activity screening.

Reaction of 6-chloro-9-benzyl-8-(methylthio)purine 3 with primary amines afforded, the corresponding 6-(substitutedamino)purines 4a-g. The latter products when methylated with methyl iodide yielded smoothly N3-methyl purinium iodide salts 5a-f rather than the probable N1- and N7-derivatives. 9-Benzyl-3-methyl-6-(methylimino)-8-(methylthio)purine 8 was obtained upon treating the purinium iodide 5a with alkali. Most of the synthesized compounds were screened for their antitumor activity.

Assessment of faba bean (Vicia faba) response to inoculation with Rhizobium leguminosarum in clay loam Nile Delta soil.

A field experiment was conducted to assess the response to inoculation with rhizobia in a clay loam soil of the Nile Delta using faba bean (Vicia faba) for two successive winter seasons (1985/6 and 1986/7). Three selected strains of Rhizobium leguminosarum, TAL 634, NRC 65 and TAL 1400, were used singly or in combination as peat-based inocula in 1985/6 winter season. Strain TAL 1400 was replaced by strain F9 in the 1986/7 winter season. A significant seed yield response was obtained only with strain TAL 1400, in the 1985/6 season. In the 1986/7 season, no significant yield response was observed with any of the strains. The serotyping of nodules collected in the 1985/6 season showed that strain TAL 1400 was more competitive than either the indigenous rhizobia or the two inoculant strains. However, the majority of nodules formed in the 1986/7 season were formed from strains other than the inoculant ones.

Distribution of extracellular proteolytic activities among various yeast.

A general screening test for extracellular proteolytic activities was carried out on 24 cultures belonging to 14 genera of yeasts. The screening was performed using gelatine and casein as sole nitrogen sources under two sets of pH conditions. Potent proteolytic yeast cultures belonging to both Ascomycetes and Deuteromycetes were detected, particularly certain members of the genera Endomycopsis, Metschnikowia, Debaromyces, Rhodotorula, and Candida spec. Most detected proteolytic cultures were active on both casein and gelatine substrates, possibly suggesting one enzyme system in each case with wide substrate specificity. Physiological studies revealed that maximum proteolysis occurred after 3--4 days of aerobic incubation and that some strains were able to hydrolyze egg albumin.

Kinetics and properties of L-glutaminase and L-asparaginase activities of Pseudomonas ovalis.

Pseudomonas ovalis produces L-glutaminase and L-asparaginase activities simultaneously upon induction by L-glutamine or L-asparagin in the growth medium. Both activities are confined to the cell during active growth and are not released into the medium. The apparent Km values are 1.4 X 10(-2) M and 6 X 10(-3) M for L-glutamine and L-asparagine substrates, respectively. Induction of both activities is substantially favoured in media with initial pH values higher than 7. In buffered yeast extract L-asparagine medium, significant amounts of L-glutaminase and L-asparaginase activities appeared towards the end of the exponential phase and along the stationary phase. The process of enzyme formation showed a firm link to the cell active growth, as evidenced by the use of growth inhibitors.

Characterization and microbiological evaluation of the red compounds, associated with red rot idsease of sugar cane.

The red coloured compounds, isolated from sugar cane tissues infected with red rot, were phenolic and included a mixture of flavonoid compounds. Two of these compounds were purified and partially characterized. Neither the mixture of the coloured compounds nor any of its individual compounds exhibited in vitro activity against the causal organism Physalospora tucumanensis. One of the purified compounds showed in vitro activity against Bacillus subtilis. The role of the red coloured compounds in the mechanism of disease resistance is discussed.