[Photosensitizing properties of 3,3'-diethylthiacarbocyanine in biological media].

The objective of the study is elucidation of perspectives of 3,3'-diathylcarbocyaine application as a photosensitizer for curing viral infections by photodynamic therapy. Lipid-containing bacteriophage PM-2 of Pseudoalteromonas espejiana was used as a model. The testing was carried out at a special installation modeling photodynamic exposure conditions towards a non-fractionated phage lysate. 3,3'-DECC demonstrated a rapid photo-bleaching when added tothe phage lysate but not to water. The initial rate of PM-2 phage photoinactivation was proportional to the square concentration of the dye in the range of 0.5-9 µmol/L. This confirms a hypothesis that the dimer is the principal photochemically active form of the dye. An improved ability to form dimers was found in the dye in the phage lysate (10-folds better than in the water). The dye formed a stable adduct with the bacteriophage material. This adduct had an extinction maximum at λ(max) = 594 nm and demonstrated the properties of a polymer (sedimentation under a low-speed centrifugation).

[Extracellular serine proteinase of Bacillus thuringiensis]. / Vnekletochnaia serinovaia proteinaza Bacillus thuringiensis.

Pure extracellular serine proteinase has been isolated from a broth filtrate of Bacillus thuringiensis, strain 69-6R by fractionation with ammonium sulfate and affinity chromatography on Sepharose 4B derivatives containing p-(omega-aminomethyl)-phenylboronic acid and cyclopeptide bacillichin as ligands. The enzyme is completely inactivated by phenylmethylsolfonyl fluoride, a specific reagent for serine proteinases, has the molecular weight of 29 000 and pI of 8.4, reveals maximal activity and stability at pH 8.5 and is inactivated at pH values below 4 and above 10 and at temperatures above 60 degrees. The enzyme hydrolyzed azokasein, bovine serum albumin and synthetic chromogenic peptide substrates, e.g. benzyloxycarbonyl-L-alanyl-L-alanyl-L-leucyl p-nitroanilide and possesses the esterolytic activity. In terms of its physico-chemical characteristics, interaction with specific inhibitors and substrates, extracellular serine proteinase from Bacillus thuringiensis can be related to subtilisins. However, its amino acid composition-Lys16, His4, Arg8, Asx28, Thr16, Ser18, Glx29, Pro12, Gly32, Ala31, Val19, Met5, Ile12, Leu18, Tyr11, Phe10, Trp4 appears to be an intermediate between that of subtilisins and intracellular serine proteinases of Bacilli.