Identification of Replication Specificity Determinants in Two Strains of Tomato Leaf Curl Virus from New Delhi

We used two strains of tomato leaf curl virus from New Delhi to investigate specificity in replication of their cognate genomes. The strains share 94% sequence identity and are referred to as severe and mild on the basis of symptoms on tomato and tobacco. Replication assays in tobacco protoplasts and plants showed that a single amino acid change, Asn10 to Asp in the N terminus of Rep protein, determines specificity for replication of the two strains based upon its interaction with the origin of replication (ori) sequences. The change of Asp10 to Asn in Rep protein of the mild strain coupled with point mutations at the 3rd and 10th nucleotides of the 13-mer binding site altered its replication ability, resulting in increased levels of virus accumulation. Similarly, changing Asn10 to Asp in Rep protein of the severe strain impaired replication of the virus and altered its severe phenotype in plants. Site-directed mutations made in ori and Asn10 of Rep protein suggested that Asn10 recognizes the third base pair of the putative binding site sequence GGTGTCGGAGTC in the severe strain.     

Chemistry of Oxadiazole Analogues: Current Status and Applications

Russian Journal of Bioorganic Chemistry - Oxadiazoles are heterocyclic compounds in numerous approved, and experimental drugs, bioactive molecules, liquid crystals, diodes and in solar cell...     

Anti-trichomonal IgA antibodies in trichomoniasis before and after treatment

Anti-trichomonal IgA antibodies were estimated by enzyme-linked immunosorbent assay (ELISA) in serum and vaginal secretions of 25 symptomatic and 25 asymptomaticTrichomonas vaginalis positive patients before and after treatment and in 25 age-matched controls. Significantly higher levels of antitrichomonad IgA antibodies were found inT. vaginalis positive patients when compared to control subjects, especially in vaginal secretions. In addition, a significant decrease in these antibodies was observed after treatment, which was more pronounced in vaginal secretions. It seems that anti-trichomonal IgA antibodies in serum and more so in vaginal secretions are directly related to and specific to the presence ofT. vaginalis in the urogenital tract.     

Spermidine and spermine stimulate the activity of T4-DNA ligase

When the ability of T4-DNA ligase from E. coli NM 989 to form higher molecular weight polymers from linearized plasmid pJDB 207 was followed, it was observed that physiological concentrations (0.5 to 1.0 mM) of spermidine and spermine greatly stimulated the formation of these polymers. The effect had a strict specificity since 1,3-diaminopropane, putrescine (1,4-diaminobutane) and N1-acetylspermidine neither stimulated nor inhibited this activity of DNA ligase. The structural analogues of spermidine, methyl bis(guanylhydrazone) and 1,1'-[(methylethanediylidene)dinitrilo]bis(3-aminoguanidine) totally abolished the stimulatory effect of spermidine on T4-DNA ligase without affecting the enzyme's basal activity.