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Sequencing and computer analysis of a variola major virus strain India-1967 (VAR-IND) genome segment (53,018 bp) from the right terminal region has been carried out. Fifty-nine potential open reading frames (ORFs) of over 60 amino acid residues were identified. Structure-function organization of the VAR-IND DNA segment was compared with the previously reported sequences from the analogous genomic regions of vaccinia virus strains Copenhagen (VAC-COP) and Western Reserve (VAC-WR) and variola virus strain Harvey (VAR-HAR). Multiple differences between VAR-IND and the strains of VAC but the high identity of VAR-IND with VAR-HAR in the genetic maps are revealed. Possible functions of the predicted viral proteins and the effect of their differences on the features of orthopoxviruses are discussed.

DNA of the variola major virus strain India-1967 in the region of HindIII M, L, I fragments has been sequenced. Analysis of this sequence of 18029 bp revealed 19 potential open reading frames (ORFs). Four proposed proteins (L2R, H9R, L5L, L6R) contain metal-binding domains. Comparison of the variola virus (VAR) and vaccinia virus strain Copenhagen (COP) sequences show that the main differences are between proteins L1R and I5R. L1R contains 6 additional amino acid residues on the C-terminus. The protein I5R of VAR contains three Ca2+ binding domains but this COP has deletions in 2 of the 3 established domains. Possible functions of the predicted viral polypeptides are discussed.

A reproducible ultramicroprocedure for quantitative RNA analysis by electrophoresis on polyacrylamide-agarose gel is described. A standard mixture of rRNA and tRNA of total amount 10 −8 –5.10 −9 g was separated into three fractions. Immediately after separation, RNA was made insoluble and stained with methylene blue, and the absorption of the RNA-methylene blue complex was measured. Relative mobilities of different RNA bands were reproduced within 2% accuracy, and deviations of the content of separate fractions did not exceed 5%.

A simple procedure is described for quantitative spectrophotometric analysis of individual subcellular particles; the procedure is based upon the method proposed earlier to measure the optical density of microdroplets in capillary flow cells. The activity of malate dehydrogenase (MDH) was determined in individual chloroplasts, nuclei, nucleoli, and nuclear membranes of the unicellularalga Acetabularia . Chloroplasts are markedly heterogeneous in their enzymatic activity. A high MDH activity is characteristic of nuclei, insignificant activity is found in nuclear membranes, and no activity is present in nucleoli.

The association-dissociation of ribosomes is caused by changes in the concentration of magnesium ions; this transformation does not involve profound conformational changes as revealed by absence of hyperchromic effect [l] , of any alterations of the ORD spectra [2,3] or of a difference in susceptibility to attack of SH-reagents [4] . Nevertheless, a remarkable difference of the conformations of RNA in associated and dissociated subunits of E. coli ribosomes has been found recently with the use of circular dichroism in the UV-region [I]. However, the latter studies did not attempt to evaluate the contribution of conformational changes with the separated subunits. The increase of dichroic absorption upon formation of 70 S particles was regarded as a direct consequence of the interaction of the contact areas of the subunits. The present communication is concerned with the circular dichroism (CD) spectra of ribosomes fixed with glutaraldehyde [5]. It was found that changes in the concentration of magnesium ions result in a change of CD spectra of flYted ribosomes similar to that observed with intact ribosomes although the former are incapable of association-dissociation. Hence, change of the CD spectrum reflects some changes of the conformation of rRNA caused by change of environment and is not a direct consequence of the association-dissociation.

Measurement of the absorbancy of ultramicrovolumes of liquids in necessary to perform in the ultramicro-scale important analytical procedures like determination of the concentrations of substances, of enzymatic activities, etc. The proposed procedure of serial analysis is based on the application of capillary flow cells and of sensitive double-wavelength microphotometer designed in this Institute. Droplets of the sample solution, of standard solution and of the solvent are sucked by means of precision microsyringe into an Uviol glass capillary tube 50–100 μm i.d. with extended tips of smaller diameter which serve the flow cells. the droplets are separated from each other with air or pentadecane layers. During the extrusion of the droplets through the capillary across light probe of the instrument, the absorbancy is recorded. Minimum length of the droplets is 150 μm, and the minimum amount of nucleotide material necessary for the determination is 1·10−10–5·10−11 g.