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N S Eremenko

Publications and source records attributed to N S Eremenko.

At least 19 recordsLinked to original sources
PubMed2003

[Characteristics of plague pathogen mutants, differing by pigment sorption signs].

Wild-type strains of plague agent Yersinia pestis are characterized by a pigmentation phenotype (Pgm+), which includes several traits: an ability of cells to adsorb pigments (Hms+), an ability to produce siderophore yersiniabactin (Ybt+) and an ability to cause lethal infections in laboratory animals (Vir+) after subcutaneous injections. All these traits are encoded in the chromosomal pgm-locus, which gets rapidly lost due to deletion. One more trait related with the Pgm+ phenotype was detected in the present study, i.e. its siderophoric activity at 28 degrees C on the indication agar plates containing chrome azurol S (Sid+). After the four phenotypic characteristics of the Pgm+ phenotype were analyzed as well as after the four pgm-locus genes (hmsF, hmsR, irp2 and fyuA/psn) were detected by the method of hybridization and PCR, we compared 33 isogenous Pgm- mutants isolated from typical Y. pestis strain 923 by Hms-. The comparison showed that the mutants differed from each other according to the analyzed properties, which suggested that they were formed by different genetic mechanisms. Apart from the known mechanism of pgm-locus deletion, which causes an irreversible loss of Hms+, Ybt+ and Vir+ properties, two more mechanisms were detected. One of them is related with insertion damages to the pgm-locus genes, which also leads to the loss of the four traits but which can be reversed by the cultivation of cells at low temperature. The other mechanism is predetermined by unknown genetic processes ensuring the formation of mutants, which loose only their Hms+ properties and which can trigger its high-frequency reversion at 28 degrees C.

Base Sequence↗
PubMed2002

[Study of PGM mutation mechanism in Yersinia pestis (plague pathogen) vaccine strain EV76].

Yersinia pestis vaccine strain EV76 is a mutant of the virulent strain which has lost the pigmentation phenotype (Pgm+). This phenotype includes three characteristics: it absorbs pigments from agar media (Hms+), produces a siderophore yersiniabactin (Ybt+), and causes a lethal disease after subcutaneous inoculation of laboratory animals (Vir+). These characteristics are lost simultaneously after high frequency spontaneous deletion of 10 kB fragment of chromosomal DNA, termed the pgm locus. We compared the pgm locus-associated genetic and phenotypical properties of the vaccine strain with those of a typical Pgm- deletion mutant of a virulent strain. The results indicate that Pgm- phenotype of the vaccine strain results not from the deletion of the pgm locus, but from the insertion inactivation of the genes located in this locus. In contrast to the deletion mutant, the vaccine strain carries sequences detected by hybridization and PCR, which are complementary to the pgm locus genes. Moreover, the vaccine strain differed from the deletion mutant by a low level of Hms+ expression, a slower rate of cell death under iron-chelated conditions at 37 degrees C, "residual virulence" upon subcutaneous inoculation, and capacity to form revertants which restore the characteristics of Pgm+ phenotype after cell growth at 12 degrees C.

Animals↗
PubMed1990

[The incidence of myopia in the children of myopic parents and the outlook for the primary prevention of this type of refraction].

The paper analyses results after investigation of free selection of families, parents myopia selected by signs and a definite minimum age of their first-order offsprings, including 108 matrimonial couples with the total number of 209 children. It was found that myopia is a hereditary sign manifesting itself in children at the age above 15 years and more in 90% of families of the first-order offsprings of the couples in whom one of the parents has this kind of refraction, and in 100% of families in whom both parents suffer from this kind of refraction. The incidence of myopic children in families in whom one or both parents have myopia ranges from 68% to 86%, and depends on the type of refraction.

Adolescent↗