Alkylation of poly(4-vinylpyridine) with methyl iodide for 12 h led to synthesis of the anionite poly(N-methyl-4-vinylpyridinium iodide). Iodination of an aqueous solution of the reaction product with an equimolar quantity of iodine in ethanol produced poly(N-methyl-4-vinylpyridinium triiodide) at quantitative yield. The structure of this compound was confirmed by UV, IR, and 1 H NMR spectroscopy and potentiometric titration. The antimicrobial activities of the compounds synthesized here are presented.

Sequencing of the cef (CHO cell elongating factor) gene of Vibrio cholerae serogroup O139 revealed one nucleotide substitution (T to C at nucleotide 2015) as compared to cef of classical V. cholerae O1 and two substitutions (GT to AC at nucleotides 2014-2015) as compared to cef of V. cholerae O1 El Tor. A comparative bioinformatic analysis showed that the substitution determines a threonine residue in position 672 of the Cef protein, while this position is occupied by an isoleucine residue in the classical strains and a valine residue in the El Tor strains. The latter two amino acids are hydrophobic, while threonine is hydro philic, having a polar R group. The nonsynonymous substitution affects the predicted secondary and, prob ably, tertiary structures of the Cef O139 protein and explained our previous finding that the protein fails to degrade tributyrin, while retaining the tweenase activity spectrum and all other characteristics. It cannot be excluded that the inability of Cef O139 to cleave triglycerides, along with other genetic specifics, contribute to the fact that the O139 serogroup has been supplanted from a dominating position in etiology of cholera by the El Tor biotype. The nucleotide sequence of the V. cholerae O139 cef gene and the deduced amino acid sequence of its product are reported for the first time and were deposited in GenBank under accession nos. JF499787 and AEC04822.1, respectively.

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