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Biomedical subjects

N P Iurina

Publications and source records attributed to N P Iurina.

14 recordsLinked to original sources
PubMed2005

[Genomics and evolution of cellular organelles].

The structure, functions, and evolution of cellular organelles are reviewed. The mitochondrial genomes of eukaryotes differ considerably in size and structural organization mainly due to the length variation in noncoding regions and the presence of introns. The mitochondrial genomes of angiosperms are the largest and most complicated. Gene content in eukaryotic mitochondrial genomes is similar. They usually encode all types of rRNA, a complete or partial complement of tRNA, and a limited number of proteins essential for mitochondrial functions. In all eukaryotes studied, mitochondrial genomes code for two highly hydrophobic proteins involved in respiration, cytochrome b and subunit 1 of cytochrome oxidase. Genome structure and gene content in plastids, mainly in higher plant chloroplasts, are highly conserved. Plastid genomes of algae are more variable in gene composition and contain several unique genes absent in the chloroplast DNA of higher plants. Plastid genomes encode proteins involved in transcription and translation, as well as proteins of the photosynthetic apparatus. Both types of cellular organelles are supposed to be of endosymbiotic origin. Modern plastids originate from a cyanobacterial ancestor. Alpha-proteobacteria, especially the most mitochondrion-like rickettsia, gave rise to mitochondria. The origin of plastids of higher plants and green algae as a result of primary endosymbiosis and that of other algal lineages by secondary endosymbiosis are briefly discussed.

Animals↗
PubMed2002

[The mitochondrial genome of protists].

The data on the structure and functions of the mitochondrial genomes of protists (Protozoa and unicellular red and green algae) are reviewed. It is emphasized that mitochondrial gene structure and composition, as well as organization of mitochondrial genomes in protists are more diverse than in multicellular eukaryotes. The gene content of mitochondrial genomes of protists are closer to those of plants than animals or fungi. In the protist mitochondrial DNA, both the universal (as in higher plants) and modified (as in animals and fungi) genetic codes are used. In the overwhelming majority of cases, protist mitochondrial genomes code for the major and minor rRNA components, some tRNAs, and about 30 proteins of the respiratory chain and ribosomes. Based on comparison of the mitochondrial genomes of various protists, the origin and evolution of mitochondria are briefly discussed.

Animals↗
PubMed1983

[Some structural properties of 80S acid protein from pea ribosomes].

The 80S acid protein from pea ribosomes similar to the L7/L12 protein from E. coli was studied. This protein was found to be rich in alanine (18 mol.%) and to contain an acid amino acids excess over basic ones, the ratio of basic amino acids to acid ones was 0.42. As in the case of other eukaryotic L7/L12 homologs studied, the N-terminal amino acid of the protein is methionine. Using the double immunodiffusion technique, no crossreaction of E. coli anti-L7/L12 with 80S acid protein from pea ribosomes was observed. It was assumed that the protein molecule contains conservative sites responsible for the specific functioning of eukaryotic L7/L12 homologs.

Amino Acids↗
PubMed1982

[Acid proteins of eukaryotic cell ribosomes. Isolation of the protein similar to E. coli L7/L12 from 80S pea ribosomes].

Using ethanol-salt extraction and ion-exchange chromatography, an acid protein was isolated from 80S pea ribosomes. The protein is localized in the large subunit, is phosphorylated and has a molecular weight of 14000 and pI of 4.7. These features and the results of a comparative study of tryptic hydrolysates of the plant protein and of the protein under study suggest that the latter is homologous to the ribosomal protein L7/L12 of a prokaryotic type.

Escherichia coli↗
PubMed1977

[Mitochondrial ribosomes].

Some present-day conceptions on the structure and physiochemical and functional properties of mitochondrial ribosomes of higher and lower eukaryotes are reviewed. Mitochondrial ribosomes are compared to the ribosomes of prokaryotic and eukaryotic types and plastid ribosomes; biogenesis and functions of mitochondrial ribosomes are also discussed.

Animals↗
PubMedDate not supplied

[Various luminescence characteristics of allocytoplasmic wheat hybrids].

Comparative studies of thermoluminescence and slow fluorescence induction were carried out on leaves of allocytoplasmic hybrids and standard regionalized wheat (cultivar Zarya). There are differences in luminescence indices between these objects correlated to the thermoluminescence and slow fluorescence induction methods. These differences allow estimation of the functional activity of the photosynthetic system. All studied allocytoplasmic hybrids exceeded the standard wheat in both luminescence indices FM/FT (slow fluorescence induction) and SA/Stot (thermoluminescence) and productivity (height of seedlings, number of ears and grains, grain mass, etc.). The highest values of FM/FT and SA/Stot and the lowest value of SC/Stot were recorded in the allocytoplasmic hybrid Igen 3 x Mironovskaya 808, which is characterized by the highest productivity.

Crosses, Genetic↗
PubMedDate not supplied

[Plastidic genome of higher plants and algae: structure and function].

The data on the structure and gene content in completely sequenced plastid (predominantly chloroplast) genomes of higher plants and algae are reviewed. In higher plants, genome structure and gene content are highly conserved. Plastid genomes of algae are less conserved and contain several unique genes, which are not found in chloroplast DNAs of higher plants. Plastid genomes encode proteins involved in transcription and translation, as well as proteins of the photosynthetic apparatus and photosynthetic metabolism. The problems of origin and evolution of plastids are briefly discussed. The data published by the first half of 2002 are presented. Use was made of databases OGMP (http://megasun.bch.umontreal.ca/ogmp/projects/other/cp_list.html) and NCBI (www.ncbi.nlm.nih.gov).

Chloroplasts↗
PubMedDate not supplied

[Isolation and partial characterization of DNA topoisomerase I from the nucleoids of white mustard chloroplasts].

DNA topoisomerase was isolated for the first time from nucleoids of white mustard (Sinapis alba L.) chloroplasts. The enzyme had a molecular weight of 70 kDa; it was ATP-independent, required the presence of mono- (K+) and bivalent (Mg2+) cations, and was capable of relaxing both negatively and positively supercoiled DNA. These results suggest that the enzyme isolated belongs to type IB DNA topoisomerases.

Cations↗
PubMedDate not supplied

[Tetrapyrrole involvement in expression regulation of a nuclear gene of low-molecular-weight plastid protein ELIP].

An inhibitor analysis was used for studying the tetrapyrrole role in the regulation of the expression of the nuclear gene encoding a low-molecular-weight protein, a stress plastid light-inducible protein ELIP. 2,2'-Dipyridyl and norflurazon were used as inhibitors. Experiments with dipyridyl demonstrated that tetrapyrroles were involved in the regulation of Elip gene expression, inhibiting it by approximately 50%. Similar results were obtained when there was photodestruction of the chloroplasts, caused by a plant treatment with norflurazon. The results confirm the involvement of the chloroplasts in the regulation of the nuclear gene expression coding for plastid proteins. Tetrapyrroles are important contributors to this process.

2,2'-Dipyridyl↗
PubMedDate not supplied

[Comparison of histone-like proteins from blue-green algae with ribosomal basic proteins of alga and wheat germ histones].

Histone-like proteins was found in blue-green alga Anacystis nidulans, which has no nucleus. F2b2, F2a2, F2a1 fractions were found in histone-like algae proteins and no fraction F1. Content of basic amino acids (arginine being prevailing in algae protein) is quite identical in histone-like algae proteins and in wheat germs histones, while the content of acid amino acids is considerably higher in algae. The presence in procaryotic cells of basic proteins similar in a number of properties to histones of higher organisms suggests that these proteins are evolutionary precursors of eucaryotic histones.

Amino Acids, Diamino↗