Human one-to-one tutoring has been shown to be a very effective form of instruction. Three contrasting hypotheses, a tutor-centered one, a student-centered one, and an interactive one could all potentially explain the effectiveness of tutoring. To test these hypotheses, analyses focused not only on the effectiveness of the tutors' moves, but also on the effectiveness of the students' construction on learning, as well as their interaction. The interaction hypothesis is further tested in the second study by manipulating the kind of tutoring tactics tutors were permitted to use. In order to promote a more interactive style of dialogue, rather than a didactic style, tutors were suppressed from giving explanations and feedback. Instead, tutors were encouraged to prompt the students. Surprisingly, students learned just as effectively even when tutors were suppressed from giving explanations and feedback. Their learning in the interactive style of tutoring is attributed to construction from deeper and a greater amount of scaffolding episodes, as well as their greater effort to take control of their own learning by reading more. What they learned from reading was limited, however, by their reading abilities.

No abstract

Aim:  To evaluate the physicochemical cell surface and adhesive properties of selected probiotic strains for human use. Methods and Results:  Probiotic strains, Bifidobacterium longum B6, Lactobacillus acidophilus ADH, Lactobacillus paracasei, Lactobacillus rhamnosus GG, Lactobacillus brevis, Lactobacillus casei, Leuconostoc mesenteroides and Pediococcus acidilactici were tested for the physicochemical properties of cell surfaces and the adhesion abilities against foodborne pathogens. Bif. longum B6 (53·6%) and Lact. rhamnosus GG (46·5%) showed the highest hydrophobicity, while the least affinity to xylene was observed in Ped. acidilactici (10·4%). Bifidobacterium longum B6 showed the strongest coaggregation phenotype with Listeria monocytogenes (53·0%), Shigella boydii (42·0%) and Staphylococcus aureus (45·9%). Lactobacillus rhamnosus GG had the strong binding ability to Caco‐2 cells and effectively inhibited the adhesion of L. monocytogenes, Salmonella Typhimurium, Sh. boydii and Staph. aureus to Caco‐2 cells. The hydrophobicity was highly correlated with coaggregative abilities and competitive inhibition, suggesting a good relationship between in vitro adhesion and in vivo colonization. Conclusion:  The results suggest that Bif. longum B6 and Lact. rhamnosus GG can be candidate probiotics available for human consumption. Significance and Impact of the Study:  Because the use of probiotic strains has been more concerned with their beneficial effects in the GI tract, it is essential to examine the potential of probiotic strains based on the physicochemical properties in terms of bacterial‐binding and adhesion capabilities.

No abstract

The rumen represents the first section of a ruminant animal's stomach, where feed is collected and mixed with microorganisms for initial digestion. The major gas produced in the rumen is CO(2) (65.5 mol%), yet the metabolic characteristics of capnophilic (CO(2)-loving) microorganisms are not well understood. Here we report the 2,314,078 base pair genome sequence of Mannheimia succiniciproducens MBEL55E, a recently isolated capnophilic Gram-negative bacterium from bovine rumen, and analyze its genome contents and metabolic characteristics. The metabolism of M. succiniciproducens was found to be well adapted to the oxygen-free rumen by using fumarate as a major electron acceptor. Genome-scale metabolic flux analysis indicated that CO(2) is important for the carboxylation of phosphoenolpyruvate to oxaloacetate, which is converted to succinic acid by the reductive tricarboxylic acid cycle and menaquinone systems. This characteristic metabolism allows highly efficient production of succinic acid, an important four-carbon industrial chemical.