An immunostimulatory DNA sequence from a probiotic strain of Bifidobacterium longum inhibits IgE production in vitro

The immunostimulatory oligodeoxynucleotide (ODN) BL07 (5'-GCGTCGGTTTCGGTGCTCAC-3') was identified from the genomic DNA of the probiotic strain Bifidobacterium longum BB536. ODN BL07 stimulated B-lymphocyte proliferation and induced interleukin-12 (IL-12) production in macrophage-like J774.1 cells. ODNs BL07 and BL07S (modified with phosphorothioate backbone) significantly inhibited immunoglobulin E (IgE) production and stimulated interferon-gamma (IFN-gamma) and IL-12 production, but did not affect IL-4 secretion in murine splenic cells of ovalbumin-primed BALB/c mice. These ODNs also significantly inhibited production of IgE in purified murine B cells in the presence of IL-4 and anti-CD40. The results suggest the potential of ODNs BL07 and BL07S in preventing IgE-related immune responses and the possible involvement of ODN BL07 in the antiallergic efficacy of B. longum BB536.     

Habitat association and seasonality in a mosaic and bimodal hybrid zone between Chorthippus brunneus and C. jacobsi (Orthoptera: Acrididae)

Understanding why some hybrid zones are bimodal and others unimodal can aid in identifying barriers to gene exchange following secondary contact. The hybrid zone between the grasshoppers Chorthippus brunneus and C. jacobsi contains a mix of allopatric parental populations and inter-mingled bimodal and unimodal sympatric populations, and provides an ideal system to examine the roles of local selection and gene flow between populations in maintaining bimodality. However, it is first necessary to confirm, over a larger spatial scale, previously identified associations between population composition and season and habitat. Here we use cline-fitting of one morphological and one song trait along two valley transects, and intervening mountains, to confirm previously identified habitat associations (mountain versus valley) and seasonal changes in population composition. As expected from previous findings of studies on a smaller spatial scale, C. jacobsi dominated mountain habitats and mixed populations dominated valleys, and C. brunneus became more prevalent in August. Controlling for habitat and incorporating into the analysis seasonal changes in cline parameters and the standard errors of parental trait values revealed wider clines than previous studies (best estimates of 6.4 to 24.5 km in our study versus 2.8 to 4.7 km in previous studies) and increased percentage of trait variance explained (52.7% and 61.5% for transects 1 and 2 respectively, versus 17.6%). Revealing such strong and consistent patterns within a complex hybrid zone will allow more focused examination of the causes of variation in bimodality in mixed populations, in particular the roles of local selection versus habitat heterogeneity and gene flow between differentiated populations.     

Mitogenic and adjuvant activities of polysaccharides from the cellular slime mold,Dictyostelium discoideum NC-4

Cell surface and extracellular polysaccharide fractions obtained from Dictyostelium discoideum NC-4 cultured in bacteria-free medium showed strong B-cell mitogenic activities. Upon periodate treatment of the extracellular polysaccharide fraction this activity completely disappeared. The extracellular polysaccharide fraction could also enhance the antibody response in vitro against sheep red blood cells.     

A swine toll-like receptor 2-expressing transfectant as a potential primary screening system for immunobiotic microorganisms

Toll-like receptor 2 (TLR2) has been shown to mediate cell signaling in response to microbial cell wall components, such as peptidoglycan, lipoteichoic acid, microbial lipoprotein, and zymosan. In this study, we cloned the swine TLR2 and used it to transfect Chinese hamster ovary K-1 cells. We demonstrated that the swine TLR2-expressing transfectant can bind not only zymosan from yeast cell wall components but also intact lactic acid bacteria, resulting in the activation of nuclear factor-kappaB. These findings suggest that the swine TLR2-expressing transfectant can be very useful for the primary screening of immunobiotic microorganisms.     

Interaction of TIP26 from a hyperthermophilic archaeon with TFB/TBP/DNA ternary complex

Interactions of TBP-interacting protein (TIP26), TBP, and TFB from a hyperthermophilic archaeon Thermococcus kodakaraensis KOD1 with TATA-DNA were examined by electrophoretic mobility shift assay. Tk-TFB formed a ternary complex with Tk-TBP and TATA-DNA. Tk-TIP26 did not inhibit the formation of this ternary complex, but interacted with it to form a TIP26/TFB/TBP/DNA quaternary complex. This interaction is rather weak, and a large excess of Tk-TIP26 over Tk-TBP is required to fully convert the TFB/TBP/DNA ternary complex to the quaternary complex. However, determination of the concentration of Tk-TIP26 and Tk-TBP in KOD1 cells by Western blotting analysis indicated that the concentration of Tk-TIP26 is approximately ten times that of Tk-TBP, suggesting that the quaternary complex might also form in vivo.     

Identification of five phospho-beta-glycosidases from Lactobacillus gasseri ATCC33323T cultured in lactose medium

Lactobacillus gasseri ATCC33323(T) has seven putative phospho-beta-glycosidase genes. Using column chromatography, we found that this strain cultured in lactose medium expresses five phospho-beta-glycosidases (LacG1, LacG2, Pbg1, Pbg2, and Pbg3), where these gene expressions can be suppressed by glucose. To our knowledge, this is the first report indicating that five glycosidases are induced from a single bacterial strain using a single carbon source, lactose.     

Extracellular agglutination factor of myxamoebae produced by Dictyostelium discoideum NC-4

A non-dialyzable specific agglutination factor of myxamoebae obtained from culture broth during the growth phase of Dictyostelium discoideum NC-4 was thermostable but the agglutination activity disappeared below pH 5.0. In the case of formalinized myxamoebae, digestion of the factor with Pronase decreased the activity, but periodate treatment of the factor did not affect the activity. Myxamoebal agglutination by this factor was inhibited by the addition of uronic acid, polyuronide (protuberic acid), and cell-surface polysaccharide prepared from the myxamoebae, but the agglutination was not affected by citric acid or glycine.The factor was purified by ethanol precipitation, column chromatography using DEAE-cellulose and Sepharose-2B, and zone electrophoresis. Chemical analysis of the purified factor gave 61.0% carbohydrate and 26.1% protein, and glucose, mannose, xylose and rhamnose (molar ratios of 9.3 : 3.2 : 2.1 : 1.0) were detected as the component sugars. The content of uronic acid was 12.9%.When the myxamoebae of the growth phase were starved in Millipore-supporting medium, the agglutination activity was detected in the supernatant of the medium.     

Seasonal changes in serum leptin of the feral raccoon (Procyon lotor) determined by canine-leptin-specific ELISA

Several reports have been published on blood leptin concentrations in feral animals, including members of the Carnivora, using a commercially available multi-species radioimmunoassay (RIA) kit with anti-human leptin antibody. However, we observed weak immunoreactivity between recombinant canine leptin and anti-human leptin antibody, suggesting a limitation in the applicability of the RIA kit for leptin assays in Carnivora species. We tested the applicability of RIA and sandwich enzyme-linked immunosorbent assay (ELISA) with anti-canine leptin antibody to assay blood leptin in the dog (Canis familiaris) and the raccoon (Procyon lotor). When RIA was used for recombinant canine leptin and dog sera, values were much lower than those determined by ELISA at higher concentrations (>10 ng/ml), while rather higher at lower concentrations (<2 ng/ml). A similar discrepancy between the two methods was found for serum leptin concentrations in raccoons. Clear seasonal variations were observed by ELISA, but not by RIA, with high values in autumn (3.46+/-0.45 ng/ml) and low values in spring and summer (0.71+/-0.07 ng/ml). Serum leptin concentrations in raccoons correlated positively with their body weight (r=0.753) and body mass index (r=0.755), corroborating our previous findings of a strong positive correlation between serum leptin concentrations and body fat content in dogs. Thus, the canine leptin ELISA is useful for assays of dog and raccoon leptin, and blood leptin is a good marker of nutritional condition in the species of Carnivora assayed in this study.