[A method for determining the individual optical characteristics of posttranslational fluorescent forms of fluorescent proteins with the use of nonlinear laser fluorimetry].

A method for determining the individual optical characteristics (fluorescence quantum yield, the rate constant and quantum yield of singlet-triplet conversion, excitation of fluorescence cross-section, extinction coefficient) and concentration correlations between the fluorescent forms of fluorescent proteins arising in the reaction of posttranslational chromophore formation has been developed, which is based on combined application of absorption spectroscopy and classical and nonlinear laser fluorimretry. The method allows one to determine the share of fluorescent forms in the mixture of chromoproteins. The individual optical characteristics of the red form of the fluorescent protein mRFP1 has been determined: the fluorescence quantum yield eta = 0.24 +/- 0.03; the extinction coefficient in the maximum of absorbance band (584 nm) epsilon = 213 +/- 40 mM(-1) cm(-1) (the cross-section of absorbance sigma = (8.2 +/- 1.5).10(-16) cm2); the constant of singlet-triplet conversion rate K32 = (0 +/- 0.6)-10970 s(-1). The part of the red form in the mixture of chromoproteins is 26 +/- 6%.

[The ajoene blockade of integrin-dependent processes in an HIV-infected cell system]. / Blokada adzhoenom integrinzavisimykh protsessov v sisteme kletok, infitsirovannykh VICh.

Ajoene, (E,Z)-4,5,9-trithiadodeca-1,6,11-triene-9-oxide, isolated from extracts of garlic (Allium sativum) has been previously shown to inhibit platelet aggregation by inactivating allosterically the platelet integrin, GP IIb/IIIa. The structural and functional similarity of integrins led the authors to suggest that ajoene may also inhibit adhesive interactions and fusion of leukocytes. Synthetic stereoisomers of ajoene synthesized by the authors exhibited equal antiaggregatory activities (IC100 approximately 50 microM for platelets; IC100 approximately 10 microM for fMLP-stimulated neutrophils). Racemic ajoene inhibited the fusion of H9 cells with HIV-infected H9:RF cells (IC50 approximately 45 microM; 16 h of incubation) and also exhibited a degree of antiviral activity (IC50 approximately 5 microM as assessed by inhibition of HIV-1/CEM/Lav 1 Bru replication in CEM13 cells; m. o. i. 0.1; 72 h). A considerable increase in the latter became evident when the compound was administered in aliquots of 50 microM per 12 h of incubation (inhibition by 30%; total concentration 0.25 microM; 72 h).(ABSTRACT TRUNCATED AT 250 WORDS)