Collagen binding by lactobacilli

¹²⁵I-labeled type I collagen (Cn-I) binding of 92 fresh isolates and 18 type culture collection strains of lactobacilli was tested. More than 75% of the strains bound Cn-I. The binding was inhibited by excess of unlabeled Cn-I, gelatin, and was sensitive to proteinase K. Other proteins such as fibronectin and albumin and various carbohydrates such asD-galactose,D-fucose, andD-mannose did not inhibit the binding. Therefore, we propose binding of Cn-I to lactobacilli involving specific surface protein(s).     

Temporal changes in the dominance of tree functional traits,but no changes in species diversity during woody plant encroachment in a Brazilian savanna

Questions : Woody encroachment in savannas has been associated with changing taxonomic composition and ecosystem function. Interestingly, there is little understanding of how encroachment impacts plant functional diversity and how those changes relate to plant demography, a crucial mediator between taxonomic composition and ecosystem function. Location : Southeastern Brazil. Methods: Using a landscape scale fire suppression experiment in a diverse Brazilian savanna, we quantify how change in species composition over seven years impacted vegetative and reproductive tree functional diversity as determined by new recruits, dead and surviving trees. Results: Over seven years, tree above-ground biomass increased by 15%, while total species richness did not change. Despite minor changes, species composition remained overall similar (82%), with few species contributing significantly to plot dissimilarity over time. There were small changes in vegetative traits, where the community-weighted mean increased in maximum tree height (↑ 2.1%) and specific leaf area (↑ 5.3%), and decreased in wood density (↓ 1.3%) and bark thickness (↓ 9.4%). Changes in reproductive traits were larger than in vegetative traits, with an increase in the prevalence of monoecy (↑ 32.6%), dioecy (↑ 44.2%), large seeds (↑ 20.3%), animal-mediated seed dispersal (↑ 4.9%) and pollination by very small insects (↑ 45.5%), and a decrease in the prevalence of hermaphroditism (↓ 9%), small seeds (6.8%) and pollination by small insects (12.5%). The overall decrease in bark thickness and increase in monoecy and dioecy were mainly driven by characters of the new recruits, while the overall increase in specific leaf area (SLA) and decrease in small seeds appeared largely determined by the loss of trees possessing those traits. Conclusions: Encroachment leads to changes that are likely increasing ecosystem vulnerability to fire and drought. Further, the compositional changes observed appear to drive marked change in reproductive traits, indicating increasing dependence on animals for dispersal and reproduction. Understanding post-hoc encroachment impacts in an era of widespread pervasive encroachment is fundamental to reconciling ecosystem functions such as nutrient cycling and pollination services as there is a loss of species with open ecosystem life-history strategies. Among savannas, there remains an urgent need to understand relationships between woody cover and ecosystem function to determine thresholds in woody cover promoting resilient savanna ecosystems.     

Sperm chromatin alterations in fertile and subfertile bulls

Alterations in sperm chromatin have been related with subfertility in several mammals. In this study, chromatin alteration types (Base, Basal half, Central axis, Dispersed, and Whole) were assessed by toluidine blue (TB) staining, 6-diamidino-2-fenilindole (DAPI) and anti-protamine 1 antibody (anti-PR1) labeling in sperm samples of fertile and subfertile bulls. Semen samples were obtained from bulls kept in Artificial Insemination Center (fertile bulls) or from bulls subjected to scrotal insulation (subfertile bulls). The percentage of chromatin alterations identified by TB was similar (P?>?0.05) in semen samples of fertile and subfertile bulls. In contrast, a greater (P?<?0.01) chromatin decondensation and heterogeneity were recorded in semen samples of subfertile bulls. In DAPI and anti-PR1 methods, the subfertile bulls samples had a higher (P?<?0.05) percentage of alteration in the base as well as overall chromatin alterations (P?<?0.05). Moreover, the chromatin alterations recorded with TB, DAPI, and anti-PR1 were compared in semen samples of fertile and subfertile bulls. In fertile bulls, the overall chromatin alterations were similar (P?>?0.05) among the methods In contrast, semen samples of subfertile bulls had a higher (P?<?0.05) percentage of overall chromatin alterations when labeled with DAPI. In conclusion, our findings shown that all dye tested had specific sperm stainability and can be feasible to monitor subfertility condition in bulls. Also, different chromatin alteration types in sperm samples of fertile and suberftile bulls were recorded.     

Growth conditions for the expression of fibronectin,collagen type I,vitronectin, and laminin binding toEscherichia coli strain NG7C

The ability ofEscherichia coli strains isolated from various human infections to bind fibronectin (Fn), collagen type I (Cn), laminin (Ln), and vitronectin (Vn) was studied. Binding of the proteins was shown to be specific and to be inhibited after protease treatment and heating of bacterial cells at 80°C. Binding of Fn, Cn type I, and Ln was not expressed in CFA broth and Voccani's medium with sodium chloride concentration above 0.5%. Fn binding was specifically enhanced for cells grown in CFA broth and Voccani's medium containing CaCl₂ (up to 10 mM final concentration), whereas binding of Cn type I was decreased. Growth in liquid medium yielded cells with maximal binding of Fn, Cn type I, Vn, and Ln after 20–22 h of growth. The binding of Fn, Cn type I, and Vn to cells of strain NG7C was inhibited for cells preincubated with antisera raised to the homologous strain;E. coli NG7C cells seem to have specific binding sites for Fn, Cn type I, Vn, and possibly also Ln.     

Interactions between parents and infants,and infants-father separation in the common marmoset (Callithrix jacchus)

The New World monkey,Callithrix jacchus, diversely from most Old World primates, shares infant care among all family members. This paper intends to describe a pattern of infant care in the common marmoset, and to verify if the infant-father separation induces a depression reaction, such as found in other separation studies. In Experiment 1, 11 families (mother, father, and twin newborn infants) ofCallithrix jacchus were observed from 1st to 36th days of infants' life. It was noted that infants were carried most of the time in the beginning of life, and that from the 4th day on this care came mostly from the father. In Experiment 2, nine families were divided in three separation groups (15, 30, and 45 days of infants' life). Each group had a control and two experimental families. Removal of the father was done for three days, beginning at the indicated infants' ages. Results showed that upon removal of the father, the mother assumes the infants' care, and no depression reaction appeared.