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O E Orlova

Publications and source records attributed to O E Orlova.

12 recordsLinked to original sources
PubMed2026

Resistance gene mutations and phylogenetic relationships in Candidozyma auris isolates from Russia.

INTRODUCTION: Candidozyma auris is an emerging healthcare-associated fungal pathogen with a high propensity for nosocomial transmission and development of antifungal resistance. This study aimed to identify resistance-associated genomic variants and characterize the phylogenetic structure of clinical C. auris isolates circulating in Russia. METHODS: We analyzed 82 isolates collected between 2017 and 2023 from 18 hospitals in the Northwestern and Central Federal Districts of the Russian Federation. Antifungal susceptibility testing was combined with whole-genome sequencing, targeted FCY2 sequencing, and comparative phylogenomic analysis using publicly available international genomes. RESULTS: All isolates analyzed in this study belonged to clade I and showed a highly conserved profile of elevated azole MICs. The consistent detection of ERG11 (K143R), TAC1B (A640V), and CDR1 (V704L) suggests that reduced azole susceptibility in this population is associated with both target-gene alteration and efflux-mediated mechanisms. All isolates remained susceptible to echinocandins in vitro, and no resistance-conferring mutations were detected in FKS1, consistent with the absence of an echinocandin-resistant phenotype. Decreased susceptibility to flucytosine was mainly associated with the FCY2 (L383*) nonsense mutation, which was confirmed by targeted Sanger sequencing in additional isolates. Phylogenomic reconstruction showed that the Russian isolates represented a restricted segment of global clade I diversity and revealed two major geographically structured lineages corresponding to two large metropolitan areas in European Russia. DISCUSSION: The distribution of closely related isolates across hospitals supports local persistence and inter-hospital dissemination of genetically related strains. These findings provide important insights into the molecular epidemiology, antifungal resistance mechanisms, and transmission dynamics of C. auris in Russia.

Phylogeny↗
PubMed2001

[Immunohistochemical study of cell phenotypes in organ culture of the rat embryo liver].

The organ culture of the liver of a 14 day old rat embryo was used for immunohistochemical recognition of the available cell types. This culture contains the tissue explant, confluent monolayer cells and a zone of single cells (ZSC). At the start of cultivation a monolayer is formed at the expense of cells slipping down together from the explant, and later these cells were seen to migrate actively from the explant and to proliferate. ZSC is formed by cells migrating from the monolayer. Desmin-containing cells (hepatoblasts, Ito cells and myofibroblasts) migrate from the explant to the monolayer and ZSC. In the monolayer hepatoblasts lose gradually desmin and are converted into cytokeratin 18 (CK-18) expressing hepatocytes. In ZSC, hepatoblasts lose desmin, but no CK-18 synthesis occurs in them. The Ito cells (hypothetical progenitor cells) are spreading over the whole culture, and desmin expression in them does not change. The embryonal Ito cells may transform presumably into myofibrils. Myofibroblasts lie flat on the periphery of ZSC. Besides, desmin myofibroblasts express alpha-actin from smooth muscles. Expression of CK-18 in cells depends on the pattern of intercellular interactions. In the monolayer, CK-18 expression extends successively via the adjacent cells towards the explant. In hepatocytes, migrating into ZSC, CK-18 expression stops. In ZSC, CK-18 expression reappears in compact clusters of stopped cells. It supposed that during formation of close contacts in the monolayer the cells-predecessors may be differentiated into hepatocytes, whereas in the case of disturbance of intercellular connections in ZSC the cells-progenitors may be converted into myofibroblasts. However, on the reconstruction of cell contacts in motionless dense clusters the cells in ZSC are differentiated into hepatocytes.

Actins↗
PubMed1998

The effect of inhibitors of arachidonic acid metabolism on proliferation and death of tumor cells.

The effect of inhibitors of arachidonic acid metabolism on proliferation and death of tumor P-388 cells in a broad concentration range was studied. Cell proliferation was estimated by the metaphase frequency and the proportion of cells in S phase; cell death was determined from lysis, staining of cells with trypan blue, nuclear damage, percentage of cells with subdiploid DNA and the type of DNA fragmentation. It was shown that low concentrations of phospholipase A2 and lipoxygenase inhibitors stimulated the proliferation of P-388 cells. At higher concentrations, the inhibitors suppressed cell proliferation by blocking the G1-S transition and induced cell death of the apoptosis type. Indomethacin, an inhibitor of cyclooxygenase, did not initiate cell death, nor did it affect the proliferation of P-388 cells at concentrations of up to 10 microM.

Acetophenones↗
PubMed1984

[Surface structure of the elementary bodies of Chlamydia].

The surface structure of chlamydial elementary bodies (strain PL-B577 causing enzootic abortion of ewes and strain CP-1 isolated from a patient with Reiter's syndrome), concentrated directly on the grid of an electron microscope, was studied by the method of negative staining. The surface of the cell wall of chlamydial elementary bodies in the preparations of crude cultures, not subjected to enzymatic purification, was formed by spherical subunits 4 nm in diameter. The surface of the cell wall of elementary bodies was found to have projections 10-20 nm long and 3-4 nm in diameter, as well as annular structures 15-22 nm in diameter in hexagonal arrangement, spaced at 45 nm and probably traversed by these projections. The number of such structures in a group was 12-15. These data correspond to the model representing the structure of the surface of chlamydiae, which was proposed by Matsumoto in 1979.

Abortion, Spontaneous↗
PubMedDate not supplied

[Growth inhibition and induction of tumor cell death by phospholipase A2 and lipoxygenase inhibitors].

We studied the effect of arachidonic acid metabolism inhibitors in a wide concentration range on the proliferation and death of lympholeukemia cells P-388. Proliferation of the cells was estimated by metaphase frequency and the proportion of cells in S phase; cellular death was determined by their lysis, trypan blue staining, damaged nuclei, the proportion of cells with subdiploid DNA content, and DNA fragmentation. Low concentrations of phospholipase A2 and lipoxygenase inhibitors were shown to stimulate cell division, while higher concentrations inhibited it by blocking G1-S transition and inducing apoptotic cellular death. Indomethacin, a cyclooxygenase inhibitor, had no effect on proliferation and induced no cell death at concentrations up to 10 microM. Inhibitors of phospholipase A2 and lipoxygenase also inhibited tumor growth in mice.

Acetophenones↗
PubMedDate not supplied

[Specific characteristics of composition of synthetic nutrient media for cultivation of Hemophilus influenzae type b from the standpoint of bacterial metabolism].

In many countries vaccination against Haemophilus influenzae of type b (Hib) has permitted the liquidation of severe generalized forms of infections caused by these bacteria. The vaccine is obtained on the basis of Hib capsular polysaccharide. To obtain pure capsular polysaccharide, Hib should be cultivated on synthetic nutrient media. The present review deals with the data substantiating the advantages of using synthetic nutrient media for the cultivation of these bacteria with a view to obtaining pure capsular polysaccharide.

Bacterial Capsules↗
PubMedDate not supplied

[Dynamics of growth of Haemophilus influenzae serotype B and synthesis of capsular polysaccharide in the process of cultivation in a synthetic nutrient medium].

The dynamics of H. influenzae, serotype b, growth and synthesis of their capsular polysaccharide in the synthetic nutrient medium, proposed by Herriot for noncapsular strains, was studied using 6 strains. The growth rate of H. influenzae, serotype b, and the amount of capsular polysaccharide, synthesized in the above mentioned medium, practically were not different from those in heart-brain broth (Difco). The possibility of minimizing the composition of Herriot's medium without any adverse effect on the amount of synthesized capsular polysaccharide was shown. As the result of these studies, the expediency of the cultivation of H. influenzae, serotype b, in the synthetic medium, intended for obtaining the preparations of capsular polysaccharide, was proved.

Bacterial Capsules↗
PubMedDate not supplied

[Changes in sensitivity of lymphocytic leukemia P388 cells to oxidative stress and platidiam upon tumor growth].

We studied the effect of oxidative stress induced by hyperoxia, hydrogen peroxide, or menadione on mouse leukemia P388 cells at early (4 days) and late (7 days) stages of tumor growth. Oxidative stress proved to inhibit cell division and to induce apoptosis. Seven-day leukemia cells feature lower proliferative potential and higher sensitivity to oxidative stress and platidiam.

Animals↗
PubMedDate not supplied

[The effect of tetracycline therapy on the laboratory indices of chlamydia infection in Reiter's disease (preliminary report)].

The authors studied the effect of tetracycline therapy (short and long courses) on the indices of chlamydia infection (antigens and antibodies) in Reiter's urogenous disease. The concentration of tetracycline in the blood serum and synovial fluid when administered in a daily dose of 2.0 g (single dose 0.5 g) was determined. It has been established that tetracycline exerts an inhibitory effect on the chlamydia infection not in all the patients suffering from Reiter's disease despite sufficient concentration of the antibiotic in biological fluids (blood serum, synovial fluid). Prolonged courses of tetracycline therapy proved most effective.

Adolescent↗
PubMedDate not supplied

[Study of viral contamination of Japanese quail and cell cultures from their embryos].

Agents identified as adenovirus CELO were isolated from organ suspensions of 1500 Japanese quails (JQ) in 4 experiments. No contaminating viruses were found in examinations of cell cultures prepared from the kidneys of 80 JQ. Negative results were obtained in examinations of 163 antigens from JQ organs in the COFAL test. Agents identified as mycoplasma were isolated in 16 cases from 736 specimens of the virus-containing fluid used for manufacture of measles virus. According to the results of the CFT, 59 antigens prepared from Japanese quail embryo cell cultures contained no oncornavirus antigens and were negative in the COFAL test. Among 1848 JQ sera examined for the presence of antibody to leukemia-sarcoma complex viruses only 2 sera were found in 1976 to contain antibody to Rous sarcoma virus. No antibody to Marek disease virus in 414 serum samples or to Newcastle disease virus in 554 sera were detected. Among 500 sera tested 30.8% contained antibody to adenovirus CELO.

Alpharetrovirus↗