Biomedical subjects

E A Pleteneva

Publications and source records attributed to E A Pleteneva.

12 recordsLinked to original sources

PubMed2006

[Genome conservatism of phiKMV-like bacteriophages (T7 supergroup) active against Pseudomonas aeruginosa].

The T7-like phiKMV bacteriophage active on Pseudomonas aeruginosa was previously isolated by us and shown to have DNA resistant to many endonucleases. A loss of sensitive sites might be a consequence of a long phiKMV evolution on different hosts. To elucidate, whether this trait is shared by other similar phages, several new phiKMV-like phages were isolated from different sources and compared. All studied phiKMV-like phages formed three groups, insignificantly differing in the number and localization of endonuclease-sensitive DNA sites. This confirms that the present-day phages of this species have highly conserved genomes. Mutational "restoration" of the lost sites may be restricted by a lethal effect. The phiKMV-like phages were shown for the first time to increase the rate of in vitro accumulation of giant phiKZ-like phages of P. aeruginosa. This effect is characteristic only of phiKMV-like phages.

Bacteriophage Typing↗

PubMed2006

[Comparison of new giant bacteriophages OBP and Lu11 of soil pseudomonads with bacteriophages of phiKZ-supergroup of Pseudomonas aeruginosa].

Study of two recently isolated giant bacteriophages Lu11 and OBP that are active on Pseudomonas putida var. Manila and Pseudomonas fluorescens, respectively, demonstrated their similarity in morphology, genome size, and size of phage particles, with giant bacteriophages of Pseudomonas aeruginosa assigned to the supergroup of phiKZ-like phages of the family Myoviridae designated in this manner according to the best studied phage phiKZ that belongs to the species of this group widely distributed in nature. Comparison of major polypeptide sizes of mature particles suggests the similarity of certain proteins in the phages examined. In OBP particles visualized with an electron microscope, an "inner body" was detected, which points to the specific DNA package intrinsic to phages of phiKZ group. In the meantime, phages Lul11 and OBP do not exhibit resemblance among themselves or with any of earlier described phiKZ-like phages in respect to other traits; particularly, they have no detectable DNA homology. Note that phage Lu11 of P. putida var. Manila exhibits very slight homology with phage Lin68 of the family of P. aeruginosa phiKZ-like phages detected only in blot hybridization. This suggests the possible involvement of these phages in interspecies recombination ("gene shuffling") between phages of various bacterial species. Results of partial sequencing of phage genomes confirmed the phylogenetic relatedness of phage OBP to phages of the phiKZ-supergroup, whereas phage Lu11 most probably belongs to a novel species that is not a member of supergroup phiKZ composition. The results of the study are discussed in terms of the evolution of these phages.

Genome, Viral↗

PubMed2004

[Comparison of genomes of new gigantic Pseudomonas aeruginosa phages from native populations from different regions].

To study the genome diversity of bacteriophages from geographically distant natural populations, new giant phi KZ-like Pseudomonas aeruginosa phages isolated in two different regions were compared with earlier known phages of three species (phi KZ, Lin68, EL). A broad spectrum of lytic activity was demonstrated for all phi KZ-like phages. Phages of the phi KZ species proved to be common in natural populations of various regions, while IL- and Lin68-related phages were extremely rare. Most phi KZ-related phages had unique DNA restriction patterns, but the differences between these were only minor, and the genomes did not contain nonhomologous fragments. The spectrum of capsid polypeptides proved to be conserved in each species, and was proposed as a character necessary and sufficient for express classification of phages with an accuracy of species. Phages isolated in different geographical regions showed no substantial difference. Some phages only slightly differing in DNA restriction pattern from phi KZ may be used to study the origin of phi KZ genes coding for orthologs of proteins of unrelated species (other phages, pathogenic bacteria, eukaryotes).

Blotting, Western↗

PubMed2002

[Phenogenetic characterization of a group of giant Phi KZ-like bacteriophages of Pseudomonas aeruginosa].

A comparative study was made of a group of Pseudomonas aeruginosa virulent giant DNA bacteriophages similar to phage phi KZ in several genetic and phenotypic properties (particle size, particle morphology, genome size, appearance of negative colonies, high productivity, broad spectrum of lytic activity, ability to overcome the suppressing effect of plasmids, absence of several DNA restriction sites, capability of general transduction, pseudolysogeny). We have recently sequenced the phage phi KZ genome (288,334 bp) [J. Mol. Biol., 2002, vol. 317, pp. 1-19]. By DNA homology, the phages were assigned to three species (represented by phage phi KZ, Lin68, and EL, respectively) and two new genera (phi KZ and EL). Restriction enzyme analysis revealed the mosaic genome structure in four phages of the phi KZ species (phi KZ, Lin21, NN, and PTB80) and two phages of the EL species (EL and RU). Comparisons with respect to phage particle size, number of structural proteins, and the N-terminal sequences of the major capsid protein confirmed the phylogenetic relatedness of the phages belonging to the phi KZ genus. The origin and evolution of the phi KZ-like phages are discussed. Analysis of protein sequences encoded by the phage phi KZ genome made it possible to assume wide migration of the phi KZ-like phages (wandering phages) among various prokaryotes and possibly eukaryotes. Since the phage phi KZ genome codes for potentially toxic proteins, caution must be exercised in the employment of large bacteriophages in phage therapy.

Biological Evolution↗

PubMed2000

[Isolation and comparative study of a group of temperate bacteriophages of rhizospheric pseudomonads Pseudomonas putida].

We have isolated several new temperate bacteriophages for rhizosphere pseudomonads Pseudomonas putida. Examination of these phages, along with two previously isolated temperate phages PP56 and PP71 of P. putida PpG1 (biovar A), allowed us to classify them into four species on the basis of DNA cross-homology; relative genomic size; and, to a certain extent, the morphology of phage particles. Two of these species are represented by nonidentical variants. No transposable phages were found among these two new species. Three phage species cause various-types of lysogenic conversion manifested in growth suppression of other phage species. This seems to account for the fact that the temperate phage of rhizosphere pseudomonads are seldom encountered. The new phages described can be used for selection of phage-resistant bacterial forms exhibiting antifungal activity that are commercially produced and used for treatment of seeds of cultivated plants.

DNA, Viral↗

PubMed1999

[x811--mutation of the Pseudomonas aeruginosa transposable phage D3112 with a pleiotropic effect].

Characteristics of Pseudomonas aeruginosa Transposable Phage D3112 carrying mutation x811 are described. x811 is a recessive mutation with pleiotropic effect. It determines a deteriorated lysis of infected or induced bacteria, a delayed replication, and a considerably decreased replication rate. In addition, the x811 mutation is expressed as the Kil phenotype, since high-temperature induction of prophage D3112 cts15 x811 does not cause an immediate decrease in the ability of bacteria to form colonies at 42 degrees C. Restriction analysis of DNA of D3112 cts15 x811 and its segregants has not revealed extended insertions or deletions. The characteristics of segregants of the D3112 cts15 x811 phage agree with the suggestion that the x811 mutation has emerged in a regulatory element (a gene or a site) that controls both expression of the entire early operon, including the "pre-early" function Kil, and the regulation of the repressor synthesis.

DNA Transposable Elements↗

PubMed1995

[Cryptic transposable phages of Pseudomonas aeruginosa].

Frequencies of nucleotide sequences homologous to phage transposons (PT) of two species, D3112 and B3, were assessed in genomes of natural Pseudomonas aeruginosa strains by the dot-blot hybridization method. These strains were incapable of liberating viable phages on a lawn of the PA01 standard indicator strain of P. aeruginosa. It was shown that the homologies detected belong to two groups, high and intermediate, with respect to homology level. Homology patterns were classified as high when they provided signals comparable to those for hybridization in a positive control; they were classified as intermediate when the hybridization level higher than the background level, but lower than in the positive control. Homologous PT sequences were designated as cryptic PT. Intact cryptic PT prophages were shown to exist in genomes of particular natural strains manifesting a high level of hybridization. However, the growth of these phages was limited by the restriction system of strain PA01. It is possible to isolate strains maintaining the growth of a portion of cryptic PT. These strains differed from P. aeruginosa with respect to the specificity of the restriction and modification system. Nevertheless, in most cases, the attempt to identify a novel host capable of maintaining growth of a cryptic PT failed. Natural strains often carry cryptic PT related to both known PT species, D3112 and B3. The frequency of cryptic PT is extremely high, reaching 30% in only strains with a high level of homology and up to 50% in all strains exhibiting homology. This high PT frequency is assumed to be associated with the considerable variation of P. aeruginosa.

DNA Transposable Elements↗

PubMed1975

[Comparative study of a group of mutant strains of Trichoderma viride, producer of cellulolytic enzymes].

In the course of selection of Trichoderma viride, the producer of cellulolytic enzymes, the group of mutant strains characterized by a higher level of productivity are isolate. It is shown that the isolated mutants possess a number of common but differing them from original strains characters. These include: the small size of colonies ("dwarfs"), a lower capacity to carry out some biochemical reactions, and increased development rate and a higher resistance to lethal effect of nitrosoguanidine and nitrosoethyl urea. The data obtained indicate that in the series of populations of successively isolated mutants observed the stabilization of variability of the levels of C1 enzyme synthesis takes place. It is also shown that, unlike original cultures, the populations of mutant strains are characterized by a higher variability of Cx enzyme activity levels as compared with C1.

Cellulase↗

PubMedDate not supplied

[Comparative study of animal viruses and a model design of their evolutionary relations].

A methodologic approach to the comparative study of viruses producing objective data not given by experimental biological studies has been developed. The comparative study is based on the quantitation of similarities of viruses based on integral differences of viruses in all the parameters under study. The results obtained permit us to consider all the viruses as a single system possessing a certain structure which reflects the degrees of similarity and differences between individual virus groups. The analysis of the immediate surroundings of each group determined 5 chains consisting of virus groups situated in the order of their retreat from the group corresponding to the Picornaviridae family. The revealed structure of the virus system allows modelling of evolutionary relations between individual virus groups to be made.

Biological Evolution↗

PubMedDate not supplied

[Numerical classification of viruses within families].

The possibility of using cluster analysis for allocation of viruses into groups having a taxonomic rank below the family was studied. As a result, a modified variant of cluster analysis is proposed which may be used for investigation of similarities and differences among viruses within individual families and formation of groups corresponding to those of a lower taxonomic rank than the family. The use of this modified variant of cluster analysis allowed the authors to distinguish groups in the majority of the families studied corresponding to ICTV genera. The data have been obtained suggesting the necessity of changing the taxonomic rank of some virus groups. The above studies have shown the possibility of developing numerical classification of viruses at the subfamily and genus levels, in other words, a single hierarchical numerical classification of viruses.

Adenoviridae↗

PubMedDate not supplied

[Classification of viruses by computer].

The study used the information mass containing information on 83 viruses characterized by 41 markers. The suitability of one of the variants of cluster analysis for virus classification was demonstrated. It was established that certain stages of automatic allotment of viruses into groups by the degree of similarity of their properties end the formation of groups which consist of viruses sufficiently close to each other by their properties and are sufficiently isolated. Comparison of these groups with the classification proposed by the ICVT established their correspondence to individual families. Analysis of the obtained classification system permits sufficiently grounded conclusions to be drawn with regard to the classification position of certain viruses, the classification of which has not yet been completed by the ICVT.

Bacteriophages↗

PubMedDate not supplied

[Methodological approaches to decreasing the number of markers for the numerical classification of viruses].

Three methodical approaches were used for reduction of the number of markers necessary for division of viruses into groups corresponding to certain families. Division of the markers into groups characterizing various properties of virions and their components as well as certain stages of virus reproduction in sensitive systems allowed some groups of markers to be excluded without losing the informative value of the marker set. The use of correlationships between markers helped to replace 64 initial parameters with 26 factors. The employment of the method of major components demonstrated the possibility of further reduction of the size of space in which virus clustering is done.

Chemical Phenomena↗