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M V Gusev

Publications and source records attributed to M V Gusev.

At least 19 recordsLinked to original sources
PubMed2003

Role of chloroplast photosystems II and I in apoptosis of pea guard cells.

Received Revision received We investigated the CN--induced apoptosis of guard cells in epidermal peels isolated from pea (Pisum sativum L.) leaves. This process was considerably stimulated by illumination and suppressed by the herbicides DCMU (an inhibitor of the electron transfer between quinones Q(A) and Q(B) in PS II) and methyl viologen (an electron acceptor from PS I). These data favor the conclusion drawn by us earlier that chloroplasts are involved in the apoptosis of guard cells. Pea mutants with impaired PS I (Chl-5), PS II (Chl-I), and PS II + PS I (Xa-17) were tested. Their lesions were confirmed by the ESR spectra of Signal I (oxidized PS I reaction centers) and Signal II (oxidized tyrosine residue Y(D) in PS II). Destruction of nuclei (a symptom of apoptosis) and their consecutive disappearance in guard cells were brought about by CN- in all the three mutants and in the normal pea plants. These results indicate that the light-induced enhancement of apoptosis of guard cells and its removal by DCMU are associated with PS II function. The effect of methyl viologen preventing CN--induced apoptosis in wild-type plants was removed or considerably decreased upon the impairment of the PS II and/or PS I activity.

Apoptosis↗
PubMed2001

Hydrogen peroxide inhibits photosynthetic electron transport in cells of cyanobacteria.

The effect of H2O2 on photosynthetic O2 evolution and photosynthetic electron transfer in cells of cyanobacteria Anabaena variabilis and Anacystis nidulans was studied. The following experiments were performed: 1) directly testing the effect of exogenous H2O2; 2) testing the effect of intracellular H2O2 generated with the use of methyl viologen (MV); 3) testing the effect of inhibiting intracellular H2O2 decomposition by salicylic acid (SA) and 3-amino-1,2,4-triazole (AT). H2O2 inhibited photosynthetic O2 evolution and light-induced reduction of p-benzoquinone (BQ) + ferricyanide (FeCy) in the Hill reaction. The I50 value for H2O2 was ~0.75 mM. Photosynthetic electron transfer in the cells treated with H2O2 was not maintained by H2O2, NH2OH, 1,5-diphenylcarbazide, tetraphenylboron, or butylated hydroxytoluene added as artificial electron donors for Photosystem (PS) II. The H2O --> CO2, H2O --> MV (involving PSII and PSI) and H2O --> BQ + FeCy (chiefly dependent on PSII) electron transfer reactions were inhibited upon incubation of the cells with MV, SA, or AT. The N,N,N,N-tetramethyl-p-phenylenediamine --> MV (chiefly dependent on PSI) electron transfer was inhibited by SA and AT but was resistant to MV. The results show that H2O2 inhibits photosynthetic electron transfer. It is unlikely that H2O2 could be a physiological electron donor in oxygenic photosynthesis.

Amitrole↗
PubMed1999

Hydrogen peroxide inhibits the growth of cyanobacteria.

H2O2 at concentrations of 10(-5)-10(-4) M suppresses phototrophic growth of Anacystis nidulans and Anabaena variabilis in dialysis culture. The growth of the cyanobacteria resumed after a long adaptation period. In batch cultures, the growth of A. nidulans and A. variabilis was suppressed after one-time addition of 10(-2)and 10(-3)-10(-2) M H2O2, respectively. Inducing intracellular H2O2 formation by adding methylviologen, vitamin K3, or phenazine methosulfate suppresses the growth of both cyanobacteria. The catalase inhibitor salicylic acid suppresses the growth of A. nidulans and A. variabilis at a concentration of 5.10(-3) M. The data suggest an inhibitory effect of H2O2 on the growth of the cyanobacteria. H2O2 is unlikely to serve as an electron donor during photosynthesis.

Anabaena↗
PubMed1992

Interaction of a synthetic peptide of the interferon alpha 2 C-terminal part with human blood leukocytes. II. Effect on protein tyrosine phosphorylation.

Tyrosine phosphorylation in human blood lymphocytes was studied as a function of stimulation with concanavalin A (ConA) and treatment of the cells with interferon alpha 2 (IFN alpha 2) and/or an IFN-derived C-terminal synthetic peptide 2438 (amino acid residues 124-138). Both IFN alpha 2 and the peptide 2438 decreased the level of protein tyrosine phosphorylation in the ConA-stimulated cells. In unstimulated cells, IFN alpha 2 increased, and the peptide 2438 decreased the level of the tyrosine phosphorylation. A possible correlation of these effects with stimulation of cell proliferation is discussed.

Blotting, Western↗
PubMed1992

Synthetic peptide with antiproliferative activity: a short C-terminal fragment of the human interferon alpha-2 molecule.

The biological activity of six synthetic peptides of the 124-144 region of the human interferon alpha-2 (IFN alpha-2) molecule was studied. Peptides were examined for their ability to inhibit mitogen induced proliferation of human blood cells in vitro. Only the peptide corresponding to the amino acid sequence 124-138 (2438) possessed IFN-like antiproliferative activity. Other tested synthetic peptides did not affect cell proliferation in this experimental system. As with the native IFN alpha-2 molecule, the inhibitory effect of the peptide 2438 was dose-dependent. On simultaneous addition of peptide 2438, antiproliferative activity of IFN alpha-2 was enhanced. Direct cytotoxic effects of synthetic peptide 2438 were not revealed. These results suggest that a synthetic peptide corresponding to the 124-138-amino acid sequence of the human IFN alpha-2 molecule serves as a cytostatic agent.

Amino Acid Sequence↗
PubMed1991

Interaction of a synthetic peptide of the interferon alpha-2 C-terminal part with human blood leukocytes. Binding to peripheral blood mononuclear cells.

A biologically active synthetic peptide, 2438, representing the 124-138 amino acid sequence of the human interferon alpha-2 (IFN alpha-2) molecule, which is known to possess IFN-like antiproliferative activity, specifically binds to human blood leukocytes. Scatchard plots reveal two different Kd values, for the 'low' and 'high' affinity binding. The interaction of the 125I-labelled peptide 2438 with the cells is not impaired by human IFN alpha-2 or cholera toxin.

B-Lymphocytes↗
PubMed1980

[Chromophore composition and nature of the absorption spectra of phycobiliproteins].

It was shown that phycobiliproteins are native pigment complexes, in which the protein quaternary structure is responsible for the aggregation of the chromophore groups covalently bound to the apoprotein. The main factor determining the structure of the phycobiliprotein absorption spectra is the excitone interaction of the chromophores, in which the number of bands in the spectrum is proportional to the number of interacting chromophores. In accordance with the number of bands (4) in the phycocyanobilin spectrum, i. e. chromophore of allophycocyanin and C-phycocyanin, and with the number of chromophores covalently linked to each one of the apoprotein molecules (2 for allophycocyanin and 3 for C-phycocyanin) their absorption spectra split into eight (2 X 4) and twelve (3 X 4) and twelve (3 X 4) bands, respectively. It is concluded that allophycocyanin is a native aggregate--dimer, while C-phycocyanin is a trimer of phycocyanobilin.

Apoproteins↗
PubMed1979

[Phycobiliproteins of blue-green, red and cryptophytic algae].

The present-day concepts on phycobiliproteins, the protein pigments of blue-green, red and cryptophyte algae are reviewed. The functions, distribution, localization, physico-chemical, spectral and immunochemical properties of phycobiliproteins are described. The properties of the polypeptide protein subunits and the composition and chemical structure of chromophores as well as their binding to the apoprotein molecules are discussed.

Amino Acid Sequence↗