Anti-inflammatory properties of intestinal Bifidobacterium strains isolated from healthy infants

Certain Bifidobacterium strains have been shown to inhibit inflammatory responses in intestinal epithelial cells. However, the precise mechanisms of these effects, including the chemical nature of the active compounds, remain to be elucidated. Here partial characterization of the anti-inflammatory properties of Bifidobacterium strains isolated from feces of healthy infants is reported. It was found that conditioned media (CM) of all strains studied are capable of attenuating tumor necrosis factor-α (TNF-α) and lipopolysaccharide- (LPS) induced inflammatory responses in the HT-29 cell line. In contrast, neither killed bifidobacterial cells, nor cell-free extracts showed such activities. Further investigations resulted in attribution of this activity to heat-stable, non-lipophilic compound(s) resistant to protease and nuclease treatments and of molecular weight less than 3 kDa. The anti-inflammatory effects were dose- and time-dependent and associated with inhibition of IκB phosphorylation and nuclear factor-κ light chain enhancer of activated B cells (NF-κB)-dependent promoter activation. The combined treatments of cells with CMs and either LPS or TNF-α, but not with CMs alone, resulted in upregulation of transforming growth factor-β1, IκBζ, and p21(CIP) mRNAs. Our data suggest certain species-specificities of the anti-inflammatory properties of bifidobacteria. This observation should prompt additional validation studies using larger set of strains and employing the tools of comparative genomics.     

Sex-biased parasitism,seasonality and sexual size dimorphism in desert rodents

We investigated seasonality of gender differences in the patterns of flea infestation in nine rodent species to test if sex-biased parasitism in terms of mean abundance, species richness, prevalence and the level of aggregation (a) varies among hosts and between seasons, and (b) is linked to sexual size dimorphism. Sexual size differences were significant in both summer and winter in Acomys cahirinus, Gerbillus pyramidum and Meriones crassus, and in winter only in Acomys russatus, Gerbillus dasyurus, Gerbillus nanus and Sekeetamys calurus. Sexual size dimorphism was male biased except for A. russatus in which it was female biased. Manifestation of sexual differences in flea infestation was different among hosts between seasons. A significant effect of sex on mean flea abundance was found in six hosts, on mean flea species richness in five hosts and on prevalence in two hosts. Male-biased parasitism was found in summer in one host only and in winter in five hosts. Female-biased parasitism occurred in winter in A. russatus. Gender differences in the slopes of the regressions of log-transformed variances against log-transformed mean abundances occurred in three hosts. No relationship was found between sexual size dimorphism and any parasitological parameter in any season using both conventional regressions and the method of independent contrasts. Our results suggest that sex-biased parasitism is a complicated phenomenon that involves several different mechanisms.     

Spatial variation in species diversity and composition of flea assemblages in small mammalian hosts: geographical distance or faunal similarity?

Aim Spatial variation in the diversity of fleas parasitic on small mammals was examined to answer three questions. (1) Is the diversity of flea assemblages repeatable among populations of the same host species? (2) Does similarity in the composition of flea assemblages among populations of the same host species decay with geographical distance, with decreasing similarity in the composition of local host faunas, or with both? (3) Does the diversity of flea assemblages correlate with climatic variables? Location The study used previously published data on 69 species of small mammals and their fleas from 24 different regions of the Holarctic. Methods The diversity of flea assemblages was measured as both species richness and the average taxonomic distinctness of their component species. Similarity between flea assemblages was measured using both the Jaccard and Morisita–Horn indices, whereas similarity in the composition of host faunas between regions (host ‘faunal’ distance) was quantified using the Jaccard index. Where appropriate, a correction was made for the potentially confounding influence of phylogeny using the independent contrasts method. Results Flea species richness varied less within than among host species, and is thus a repeatable host species character; the same was not true of the taxonomic distinctness of flea assemblages. In almost all host species found in at least five regions, similarity in flea assemblages decreased with increases in either or both geographical and faunal distance. In most host species, the diversity of flea assemblages correlated with one or more climatic variable, in particular mean winter temperature. Main conclusions Spatial variation in flea diversity among populations of the same mammal species is constrained by the fact that it appears to be a species character, but is also driven by local climatic conditions. The results highlight how ecological processes interact with co‐evolutionary history to determine local parasite biodiversity.     

Synthesis and Biological Properties of a Number of Analogs of DSIP and Its KND Endogenous Prototype

Russian Journal of Bioorganic Chemistry - We performed a computer search for the DSIP homologous structures in the protein data bases and found the KND peptide (WKGGDNASGE), which was closely...     

Urease immobilization on macroporous silicas

Urease was immobilized on macroporous silicas using gamma-aminopropyl triethoxysilane and glutaraldehyde. The amount of protein on the surface, the structure of pores of the support and the purity of the initial enzyme were varied, the enzymic activity of the immobilized preparations being controlled. After the immobilization of sufficiently large quantities of the enzyme (about 3 mg protein per m2 support) about 35% of the specific activity was retained. The maximum activity per unit weight of the support was observed for silicagels and silochromes with the mean diameter of pores 70-90 nm and the specific surface area about 70 m2/g. The use of purified urease produced highly active preparations of the immobilized enzyme (17,000 U per g dry support). Freeze-drying of the immobilized enzyme in the presence of sorbitol yielded dry preparations retaining their activity.     

The biosorption of cadmium and cobalt and iron ions by yeast <Emphasis Type="Italic">Cryptococcus humicola</Emphasis> at nitrogen starvation

Yeasts Cryptococcus humicola accumulated cadmium, cobalt, and iron (~?50, 17, and 4% of the content in the medium, respectively) from the medium containing glucose, phosphate, and 2 mmol/L of metal salts. The effects of metal absorption on the levels of orthophosphate (Pi) and inorganic polyphosphate (polyP) varied for the metals under study. The levels of Pi and polyP increased in the case of cadmium and cobalt, respectively. In the case of iron, no changes in the levels of Pi and polyP were observed. Multiple DAPI-stained polyP inclusions were observed in the cytoplasm of cadmium-containing cells. The intensity of DAPI staining of the cell wall especially increased in case of cobalt and iron accumulation.     

Lectin and mitotic activities in root meristems of winter wheat under oryzalin effect

The effect of oryzalin, a microtubule polymerization inhibitor (10 MM), on lectin and mitotic activities (mitotic index and duration of mitotic phases) was studied in unhardened (23 degrees C) and hardened (7 days, 2-3 degrees C) winter wheat seedlings. Three wheat cultivars differing in their frost tolerance were compared. Oryzalin treatment (3 h) decreased activity of soluble lectins, increased activity of cell wall lectin mitotic index. Under these conditions, prolongation of anaphases and disappearance of telophases were detected. Plant hardening reduced the sensitivity of cell wall lectins and mitotic activity to the cytoskeleton inhibitor due, presumably, to the appearance of cold-stable microtubules. Plant growing and hardening with oryzalin stopped mitoses and caused the appearance of polyploid cells and cells with micronuclei. These abnormalities were preserved after hardening. The results obtained demonstrate an important role of microtubules in adaptation of plants to low temperature.     

Clinical and immunological characteristics of rubella in western Siberia

Evaluations of immune system of 155 patients with rubella and 90 contacts with patients were examined. Detection of viral genetic material in blood, urine, and nasopharyngeal swabs has been performed using RT-PCR method. Clinical diagnosis has been confirmed by RT-PCR in 114 (73.5%) patients. Changes of laboratory tests for rubella without clinical signs of the infection were observed in 20% of contacts. Complex ELISA- and PCR-assisted examination of patients can help to determine the stage of disease and characteristics of immune response. For differential diagnostic of rubella and other infectious diseases with exanthema it is rational to perform complex examination of patients using immunologic and molecular biologic methods.     

Effects of abscisic acid,low temperature,and plant age on cytoskeleton and phosphorylated proteins

The effects of exogenous abscisic acid (ABA), low temperature, and seedling age on the content of tubulin, actin, and phosphorylated proteins and the structural organization of microtubules (MTs) in cells of different tissues and organs of winter wheat cultivars contrasting in cold hardiness were studied by immunocytochemical methods using monoclonal (against - and -tubulin and actin) and polyclonal (phosphothreonine) antibodies. The leaves and roots of five- and nine- day-old seedlings of three cultivars were characterized by unequal proportion of actin/tubulin proteins. ABA decreased the content of the cytoskeleton and the 60-kD phosphorylated proteins, thus promoting a decrease in the number of MTs and occurrence of a less branched network of weakly fluorescent tubulin components in the cells of the root differentiating zone (which is most responsible for the development of cold hardiness in wheat). Although the cold acclimation of plants (3°C, 7 days) did not change the level of tubulin and actin proteins, it evoked the spatial aggregation of MT, leading to formation of a dense network of tubulin cytoskeleton comprised of thick bundles of intensively fluorescent MTs. In the case of a combined action of the studied factors, low temperatures abolished the hormone effect described above, evoking an increase in the content of the cytoskeletal and 60-kD phosphorylated proteins and MT structures. We suggest that the ABA-induced decrease in the levels of proteins and MTs occurs at the initial stages of plant cold acclimation (3°C, 2-3 days). It may be the signal that triggers the processes of low-temperature adaptation. As the duration of cold acclimation increased (3°C, 7 days), the role of ABA in the formation of plant tolerance decreased. Apparently, in this case other hormone-independent mechanisms of frost hardiness development are triggered, in which the role of the cytoskeleton components and cytoskeleton-associated proteins increases.