Biomedical subjects

V A Berdnikov

Publications and source records attributed to V A Berdnikov.

At least 19 recordsLinked to original sources

PubMed2005

A mutation, tl2, in pea (Pisum sativum L.) affects leaf development only in the heterozygous state.

After gamma irradiation of pea seeds, a mutation designated as tendril-less2 (tl2) was induced. In the heterozygous state, it transforms tendrils into very narrow leaflets that resemble the heterozygote phenotype of the classic tl mutation. The tendrils of the double heterozygote tl2/+, tl/+ are converted into oval leaflets. Unlike tl, the novel mutation in the homozygous state does not affect tendrils. The leaf phenotype of homozygotes tl2/tl2 and Tl2/Tl2 do not differ in the tl/+ background. However, the anthocyanin pigmentation is strongly suppressed in petals of tl2/tl2 plants. Some hypotheses to explain the unusual phenotypic manifestation of tl2 are suggested.

Electrophoresis↗

PubMed2005

Structure of allelic variants of subtype 5 of histone H1 in pea Pisum sativum L.

The pea genome contains seven histone H1 genes encoding different subtypes. Previously, the DNA sequence of only one gene, His1, coding for the subtype H1-1, had been identified. We isolated a histone H1 allele from a pea genomic DNA library. Data from the electrophoretic mobility of the pea H1 subtypes and their N-bromosuccinimide cleavage products indicated that the newly isolated gene corresponded to the H1-5 subtype encoded by His5. We confirmed this result by sequencing the gene from three pea lines with H1-5 allelic variants of altered electrophoretic mobility. The allele of the slow H1-5 variant differed from the standard allele by a nucleotide substitution that caused the replacement of the positively charged lysine with asparagine in the DNA-interacting domain of the histone molecule. A temperature-related occurrence had previously been demonstrated for this H1-5 variant in a study on a worldwide collection of pea germplasm. The variant tended to occur at higher frequencies in geographic regions with a cold climate. The fast allelic variant of H1-5 displayed a deletion resulting in the loss of a duplicated pentapeptide in the C-terminal domain.

Alleles↗

PubMed2003

Tertiary trisomics in the garden pea as a model of B chromosome evolution in plants.

It is hypothesized that, in plants, genetically empty B chromosomes may originate from the extra chromosome (E) of tertiary trisomics if (i) the region of basic chromosomes homologous to the E (H-region) harbors a sporophytic lethal covered by the wild-type allele in E, and (ii) crossing-over between E and the H-region is suppressed. Under these conditions, most loss-of-function mutations occurring in the H-region are deleterious for haploid gametophytes, whereas those occurring in E are neutral or advantageous for hyperploid (n+1) gametophytes. As a result, natural selection at the gametophyte level can lead to the degeneration of E, leaving the H-region intact. Using Hammarlund translocation T(3-6)a, we synthesized two trisomic lines of the garden pea (Pisum sativum L.), where E was composed of the short arms of chromosomes 3 and 6 and the H-region carried recessive markers. In the trisomic line TRIS, we found few crossovers between E and the H-region. In the trisomic line TRUST, obtained after a change of basic chromosome constitution, recombination in this region was completely suppressed. After induction in the H-region of TRUST of a recessive sporophytic mutation rmv, two 15-chromosome lines of stable trisomics were established. One of them passed 11 generations, having produced more than 6000 individuals, all of them trisomic, and E remained present as a single element with no pairing partners. No tetrasomics were detected in these lines. If such trisomics occurred in nature, their extra chromosomes are likely to become a B chromosome.

Chromosomes, Plant↗

PubMed2002

Mortality of pollen grains may result from errors of meiosis: study of pollen tetrads in Typha latifolia L.

In the cattail Typha latifolia the four haploid products of meiosis remain attached and form the flat tetrad of pollen grains. Gametophytic lethals arisen de novo in diploid cells of sporophyte must manifest themselves as pollen tetrads with two dead grains. This could allow to estimate the rate of recessive lethals arresting pollen grain development. We studied pollen samples collected from 44 sprouts in two populations in the vicinity of Novosibirsk. The anomalous tetrads T1, T2, T3, and T4 carrying one, two, three, and four dead grains, respectively, were detected in each sampled individual. The mean frequency of all anomalous tetrads in the two populations was 3.4% and 8.7%. The frequencies of tetrad classes varied widely among the individuals with correlation coefficient up to 0.94, but their ratios remained nearly constant. The majority of anomalous tetrads were presented by T1 and T2 classes (their sum comprising 72.7 and 74.0% in two populations), T1 being a little more abundant. The observed pattern of frequencies of tetrads with dead grains can be explained by errors of male meiosis such as chromosome non-disjunction in both meiotic divisions. The tetrads with two dead pollen grains may result mostly from non-disjunction in anaphase I, and those with one pollen grain from non-disjunction in anaphase II, thus making tetrad analysis ineffective for estimating the rate of gametophytic lethals.

Chromosome Mapping↗

PubMed1982

[Determination of lysine residue number, positive charge and molecular lengths of histone H1 and H5 by a method of incomplete succinylation].

A simple method for determination of lysine residue number and positive charge of histones H1 and H5 in the acetic acid -- urea system has been developed. The method is based on incomplete succinylation of lysine residues and allows an accurate determination of protein molecular length. The accuracy of the method has been demonstrated by determination of goose and chicken histones H5 and their fragments. The calibrating curve for determination of molecular lengths of histones H1 and H5 has been plotted. Using the incomplete succinylation method, a detailed analysis of Lymantria dispar histone H1 structure has been carried out. The method under discussion can be used for determining lysine residue number, positive charge and molecular length of practically any protein.

Acylation↗

PubMed1981

[Histones of Salmonidae fishes. Comparative study of histones from different species and intraspecies variability of Oncorhynchus nerka H1].

The comparative electrophoretic properties of erythrocyte histones from 7 Salmonidae species were investigated. Using Na-SDS gel electrophoresis, it was shown that all the species studied possess the erythrocyte-specific fraction of histone H5. High resolution gel electrophoresis in acetic acid--urea gels demonstrated differences in the subfractional composition of histone H1 from erythrocytes and liver of O. nerka. The analysis of the sample of 40 individuals from the same population revealed the existence of intraspecies polymorphism in histone H1 subfractional composition.

Animals↗

PubMed1978

[Study of evolutionary changes in subfraction composition of histone H1 in birds].

Analysis of electrophoretic mobility of histone H1 subfractions from liver, brain and erythrocytes of 41 bird species was carried out. Subfractions of erythrocyte H1 histones from each species were compared with those of thrush Turdus musicus. The majority of species proved to possess a set of electrophoretically similar subfractions. Interspecific differences in histone H1 were mainly due to the differences in the ratio of those subfractions. The identity of the electrophoretic mobility and similar contribution to H1 histone from the respective tissues in different species permits to consider certain subfractions as homologous ones. The conservation of electrophoretic mobility for homologous subfractions of the birds of different orders shows a high evolutionary conservatism of the corresponding genes. It seems that in the course of evolution only a change in the expression of some of those genes occurs.

Animals↗

PubMed1978

[Microelectrophoretic analysis of histones from single chromosomes and nucleoli of mosquito (Chironomis plumosus) larvae].

A simple method of microelectrophoresis for histone analysis from single fragments of polythenic chromosomes of chironomid salivary glands has been developed. The chromosomes or their fragments obtained micrurgically were dissolved in a microdroplet of 8 M urea and 1 N sulfuric acid solution. Electrophoresis was performed in 30--60 m diameter polyacrylamide gel cylinders under a layer of vaseline oil. The histones were separated into 6 electrophoretic bands which correspond to fractions H4, H2b, H2a+H3, H3-dimer, and two subfractions of histone H1. Comparison of histone electrophoregrams of the I, II, and III chromosomes showed their almost absolute identity. The ratio of fractions H4, H3, H2A, H2B as well as the ratio of histone H1 subfractions in the nucleus and in the rest of the IV chromosome cannot be visually distinguished.

Cell Fractionation↗

PubMed1977