HDL2c--a new subclass of high density lipoproteins in the plasma of newborns]

A new subclass of high density lipoproteins designated as HLD2c was found in the human blood plasma of newborn by analytic ultracentrifugation in the flotation rate interval Fo1,20 8.0--12.0. HDL2c was isolated from the total HDL fraction of newborn by preparative ultracentrifugation at the density 1.071.     

Hydrogen evolution by subchloroplast preparations of photosystem II from pea and spinach,

Covalent coupling of bovine rhodopsin to CPG-thiol glass was used for separation of CNBr peptides. It is shown that cysteine residues 322 and 323 in the C-terminal cytoplasmic fragment of rhodopsin are modified with palmitic acid.     

Effect of extraction and subsequent addition of manganese ions on photooxidation of chlorophyll P(680) in the photosystem II preparations

Effect of reversible removal of Mn on the amplitude of photoinduced absorbance changes (ΔA) related to photooxidation of chlorophyll P(680) in pea oxygen -- evolving photosystem 2 (PS(2)) preparations has been studies. It is shown that after complete removal of Mn the amplitude of ΔA is increased by a factor of 7--8 and it is decreased again to the initial value upon subsequent addition of MnCl(2). This reactivation needs four Mn atoms per one reaction centre (RC) of PS(2). In the presence of 3 μM MgCI(2) the reactivation requires two Mn atoms per RC of PS2. The obtained data confirm our earlier conclusion that a four-atomic Mn centre functions in the donor side of PS(2); two of them can be replaced by either Mg(2+) or other divalent metals.     

Magnetic interaction of manganese with pheophytin anion-radical and chlorophyll cation-radical in reaction centers of the photosystem II

The influence of Mn on saturation curves of ESR spectra of Ph(-) and P(+)(680) at 1-200K in samples with different content of Mn has been studied. An analysis of these data and those on photoinduced changes of fluorescence yield of chlorophyll leads to the conclusion that the Mn-containing centre in Photosystem 2 is a cluster of 4 Mn atoms, two of which can be replaced by Mg(2+) or any other divalent metal. The distances between Mn Na Ph as well as between Mn and P(680) have been estimated.     

Features of mutated changes of genomic RNA of cold-adapted and hr-variants of influenza group A virus, detected by RNA:RNA hybridization]

The presence of mutations in the majority of the genes of cold-adapted strains A/Leningrad/134/17/57 (H2N2), A/Leningrad/134/47/57 (H2N2) and A/PR/8/59/1 (H1N1) of influenza A virus has been demonstrated by the RNA-RNA hybridization with the subsequent electrophoresis of double-stranded RNA in 7.5% polyacrylamide gel. The strains were cultivated 17, 47 and 59 passages in the chicken embryos at 25 degrees C. In the genomes of variants passaged in chicken embryos at optimal temperature of incubation 36 degrees C (hr-variants) the used technique permits identification of a single mutant gene. The obtained data suppose the attenuation of cold-adapted vaccine strains of influenza A virus and their high genetic stability to be a result of selection of the variants obtaining multiple mutations in the genome during passaging of the virions at cold temperature. The attenuation of hr-variants is defined by 1-2 mutations (first of all in HA-gene) that makes understandable their inability to serve as donors for recombinant live influenza vaccines construction.     

Synthesis of the tetrasaccharide repeating-unit of the O-specific polysaccharide from Salmonella senftenberg

The oligosaccharide β-d-Man-(1 → 4)-α-l-Rha (1 → 3)-d-Gal-(6 ← 1)-α-d-Glc, which is the repeating unit of the O-specific polysaccharide chain of the lipopolysaccharide from Salmonella senftenberg, was obtained by glycosylation of benzyl 2,4-di-O-benzyl-6-O-(2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-d-glucopyranosyl)-β-d-galactopyranoside or benzyl 2-O-acetyl-6-O-(2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-d-glucopyranosyl)-β-d-galactopyranoside with 3-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β-d-mannopyranosyl)-β-l-rhamnopyranose 1,2-(methyl orthoacetate) followed by removal of protecting groups.     

The primary photoreactions in the complex cytochrome-P-890 · P-760 (bacteriopheophytin760) of Chromatium minutissimum at low redox potentials

Experimental evidence for electron transfer, photosensitized by bacteriochlorophyll, from cytochrome c to a pigment complex P-760 (involving bacteriopheophytin-760 and also bacteriochlorophyll-800) in the reaction centers of Chromatium minutissimum has been described. This photoreaction occurs between 77 and 293 °K at a redox potential of the medium between ?250 and ?530 mV. Photoreduction of P-760 is accompanied by development of a wide absorption band at 650 nm and of an EPR signal with g = 2.0025±0.0005 and linewidth of 12.5±0.5 G, which are characteristic of the pigment radical anion.It is suggested that the photoreduction of P-760 occurs under the interaction of reduced cytochrome c with the reaction center state P⁺-890 · P^?-760 which is induced by light. The existence of short-lived state P⁺-890 · P^?-760 is indicated by the recombination luminescence with activation energy of 0.12 eV and $\text{τ}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{< 6}\text{ns}$. This luminescence is excited and emitted by bacteriochlorophyll and disappears when P-760 is reduced.At low redox potentials, the flash-induced absorbance changes related to the formation of the carotenoid triplet state with $\text{τ}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 6 μ}\text{s}$ at 20 °C are observed. This state is not formed when P-760 is reduced at 293 and 160 °K. It is assumed that this state is formed from the reaction center state P⁺-890 · P^?-760, which appears to be a primary product of light reaction in the bacterial reaction centers and which is probably identical with the state P^F described in recent works.