Effect of Panavir on influenza A virus reproduction]

Mitogenic properties of panavir, as well as its effect on the grippe virus reproduction in cell systems in vitro and the effect on the survival of mice with the experimental grippe infection were studied. It was shown that panavir had no cytotoxic action whereas it was characterized by pronounced mitogenic activity and subsequently could be considered as a perspective immunomodulator. Under in vitro conditions with the use of relatively high doses for the cell contamination with the grippe virus, panavir lowered the virus production in the cell systems. When the contaminating doses were low, panavir inhibited the virus production detected at the early stages of the infection. In the in vivo studies on mice with the experimental grippe infection panavir showed antigrippe activity against both the romantadine resistant and the remantadine nonresistant populations of the grippe A virus.     

Bioleaching of sulfidic tailing samples with a novel, vacuum-positive pressure driven bioreactor

This study presents a design for a novel bioreactor that uses alternating vacuum and positive pressure cycles to transfer acidic leach solution in and out of contact with finely ground sulfidic mine tailings. These tailings constitute an environmental problem that needs experimental data to support the development of management and control strategies. A conventional stirred tank bioreactor was used as a reference system. Both bioreactors were inoculated with mixed cultures of acidophilic iron and sulfur oxidizers. The rate of the bioleaching of tailings was 0.50 +/- 0.14 g Fe/L . day in the stirred tank bioreactor and 0.17 +/- 0.05 g Fe/L . day in the novel bioreactor. Microbial populations were identified in the two-bioreactor systems by analysis of 16S rRNA genes involving amplification, denaturing gradient gel electrophoresis (DGGE), cloning, and sequencing. The inoculum contained sulfur-oxidizing Acidithiobacillus caldus and Acidithiobacillus thiooxidans, iron oxidizers from the genera Leptospirillum and Ferroplasma, and a chemoorganotrophic Alicyclobacillus sp. During bioleaching of the tailings, the microbial populations in both bioreactors were similar to the inoculum culture, except that At. thiooxidans outgrew At. caldus. Sequences consistent with a Sulfobacillus sp. were amplified from both bioreactor samples although this bacterium was initially below the level of detection in the inoculum. After prolonged operation, Ferroplasma acidiphilum and an uncultured bacterium related to the CFB group were also detected in the novel bioreactor, whereas Sulfobacillus sp. was no longer detected. The novel bioreactor has potential uses in other areas of environmental biotechnology that involves periodic contact of liquids with solid substrates.     

A natural intergenotypic recombinant of hepatitis C virus identified in St. Petersburg

Hepatitis C virus (HCV) evolution is thought to proceed by mutations within the six genotypes. Here, we report on a viable spontaneous HCV recombinant and we show that recombination may play a role in the evolution of this virus. Previously, 149 HCV strains from St. Petersburg had been subtyped by limited sequencing within the NS5B region. In the present study, the core regions of 41 of these strains were sequenced to investigate the concordance of HCV genotyping for these two genomic regions. Two phylogenetically related HCV strains were found to belong to different subtypes, 2k and 1b, according to sequence analysis of the 5' untranslated region (5'UTR)-core and the NS5B regions, respectively. By sequencing of the E2-p7-NS2 region, the crossover point was mapped within the NS2 region, probably between positions 3175 and 3176 (according to the numbering system for strain pj6CF). Sequencing of the 5'UTR-core regions of four other HCV strains, phylogenetically related to the above-mentioned two strains (based on analysis within the NS5B region), revealed that these four strains were also recombinants. Since a nonrecombinant 2k strain was found in St. Petersburg, the recombination may have taken place there around a decade ago. Since the frequency of this recombinant is now high enough to allow the detection of the recombinant in a fraction of the city's population, it seems to be actively spreading there. The reported recombinant is tentatively designated RF1-2k/1b, in agreement with the nomenclature used for HIV recombinants. Recombination between HCV genotypes must now be considered in the classification, laboratory diagnosis, and treatment of HCV infection.     

Structure–Activity Relationship Prediction-Based Synthesis and Cytotoxicity Evaluation against the HEp-2 Laryngeal Carcinoma Cell of Isoflavone–Cytisine Mannich Bases

QSAR analysis of previously synthesized and nature-inspired virtual isoflavone-cytisine hybrids against the HEp-2 laryngeal carcinoma cell lines was performed using the OCHEM web platform. The validation of the models using an external test set proved that the models can be used to predict the activity of newly designed compounds such as 8-cytisinylmethyl derivatives of 5,7- and 6,7-dihydroxyisoflavones. The synthetic procedure for selective aminomethylation of 5,7-dihydroxyisoflavones with cytisine was developed. In vitro testing identified compound 7 f with cisplatin-level cytotoxicity against HEp-2 cell lines and compound 10 which was twice active than cisplatin after 72 h of incubation.     

Expression of hormonal carcinogenesis genes and related regulatory microRNAs in uterus and ovaries of DDT-treated female rats

The insecticide dichlorodiphenyltrichloroethane (DDT) is a nonmutagenic xenobiotic compound able to exert estrogen-like effects resulting in activation of estrogen receptor-α (ERα) followed by changed expression of its downstream target genes. In addition, studies performed over recent years suggest that DDT may also influence expression of microRNAs. However, an impact of DDT on expression of ER, microRNAs, and related target genes has not been fully elucidated. Here, using real-time PCR, we assessed changes in expression of key genes involved in hormonal carcinogenesis as well as potentially related regulatory oncogenic/tumor suppressor microRNAs and their target genes in the uterus and ovaries of female Wistar rats during single and chronic multiple-dose DDT exposure. We found that applying DDT results in altered expression of microRNAs-221, -222, -205, -126a, and -429, their target genes (Pten, Dicer1), as well as genes involved in hormonal carcinogenesis (Esr1, Pgr, Ccnd1, Cyp19a1). Notably, Cyp19a1 expression seems to be also regulated by microRNAs-221, -222, and -205. The data suggest that epigenetic effects induced by DDT as a potential carcinogen may be based on at least two mechanisms: (i) activation of ERα followed by altered expression of the target genes encoding receptor Pgr and Ccnd1 as well as impaired expression of Cyp19a1, affecting, thereby, cell hormone balance; and (ii) changed expression of microRNAs resulting in impaired expression of related target genes including reduced level of Cyp19a1 mRNA.     

The human formin FHOD1 contains a bipartite structure of FH3 and GTPase-binding domains required for activation

Formins induce the nucleation and polymerization of unbranched actin filaments. They share three homology domains required for profilin binding, actin polymerization, and regulation. Diaphanous-related formins (DRFs) are activated by GTPases of the Rho/Rac family, whose interaction with the N-terminal formin domain is thought to displace a C-terminal Diaphanous-autoregulatory domain (DAD). We have determined the structure of the N-terminal domains of FHOD1 consisting of a GTPase-binding domain (GBD) and the DAD-recognition domain FH3. In contrast to the formin mDia1, the FHOD1-GBD reveals a ubiquitin superfold as found similarly in c-Raf1 or PI3 kinase. This GBD is recruited by Rac and Ras GTPases in cells and plays an essential role for FHOD1-mediated actin remodeling. The FHOD1-FH3 domain is composed of five armadillo repeats, similarly to other formins. Mutation of one residue in the predicted DAD-interaction surface efficiently activates FHOD1 in cells. These results demonstrate that DRFs have evolved different molecular solutions to govern their autoregulation and GTPase specificity.     

The effect of long-term lactobacilli (lactic acid bacteria) enteral treatment on the central nervous system of growing rats

The aim of this study was to explore the relationship between consumption of large doses of lactic acid bacteria (LAB) and the behaviour and brain morphobiochemistry of normal growing rats. Four groups of rats were treated with LAB cultures twice daily for 6 months. The control group received 1 ml of saline per treatment, while two experimental groups received 1 ml of living bacteria (Lactobacillus plantarum and Lactobacillus fermentum, respectively) and the remaining group received a heat-treated (inactivated) L. fermentum culture. After 2 and 6 months of treatment, respectively, eight animals from each group were sacrificed, and specimens were taken for further analyses. The behaviour of the rats was evaluated five times in an open-field test at monthly intervals throughout the study. Lactobacilli treatment for 2 months induced changes in the motoric behaviour of the rats. The concentration of the astrocytesoluble and filament glial fibrillary acidic protein (GFAP) decreased in the posterior part of the hemispheres, including the thalamus, hippocampus and cortex of the rats treated with L. fermentum. A greater decrease in filament GFAP (up to 50%) was shown in the group receiving the live form of L. fermentum. In contrast, the GFAP in the live L. plantarum-treated group increased, showing elevated levels of the soluble and filament forms of GFAP in the posterior part of the hemispheres.A 60–66% decrease in the amount of the astrocyte-specific Ca-binding protein S-100b was shown in the posterior parts of the hemispheres and in the hindbrain of rats given LAB for 2 months.Prolonged feeding with LAB for 4 months up to full adulthood led to a further decrease in astrocyte reaction, reflected as an additional decrease in the amount of soluble GFAP and locomotor activity in all experimental groups. The changes in filament GFAP and S-100b appeared to disappear after prolonged feeding (total of 6 months) with LAB.In summary, LAB dietary treatment affected the ontogenetic development of the astrocytes, with the highest intensity observed in the early stages of rat development. It can be postulated that LAB treatment may play a preventive role in neurological diseases by decreasing astrocyte reaction and, consequently, lowering locomotor activity.     

A model of visual detection of angular speed for bees

A fly or bee's responses to widefield image motion depend on two basic parameters: temporal frequency and angular speed. Rotational optic flow is monitored using temporal frequency analysers, whereas translational optic flow seems to be monitored in terms of angular speed. Here we present a possible model of an angular speed detector which processes input signals through two parallel channels. The output of the detector is taken as the ratio of the two channels’ outputs. This operation amplifies angular speed sensitivity and depresses temporal frequency tuning. We analyse the behaviour of two versions of this model with different filtering properties in response to a variety of input signals. We then embody the detector in a simulated agent's visual system and explore its behaviour in experiments on speed control and odometry. The latter leads us to suggest a new algorithm for optic flow driven odometry.