The Bifidobacterium dentium Bd1 Genome Sequence Reflects Its Genetic Adaptation to the Human Oral Cavity

Bifidobacteria, one of the relatively dominant components of the human intestinal microbiota, are considered one of the key groups of beneficial intestinal bacteria (probiotic bacteria). However, in addition to health-promoting taxa, the genus Bifidobacterium also includes Bifidobacterium dentium, an opportunistic cariogenic pathogen. The genetic basis for the ability of B. dentium to survive in the oral cavity and contribute to caries development is not understood. The genome of B. dentium Bd1, a strain isolated from dental caries, was sequenced to completion to uncover a single circular 2,636,368 base pair chromosome with 2,143 predicted open reading frames. Annotation of the genome sequence revealed multiple ways in which B. dentium has adapted to the oral environment through specialized nutrient acquisition, defences against antimicrobials, and gene products that increase fitness and competitiveness within the oral niche. B. dentium Bd1 was shown to metabolize a wide variety of carbohydrates, consistent with genome-based predictions, while colonization and persistence factors implicated in tissue adhesion, acid tolerance, and the metabolism of human saliva-derived compounds were also identified. Global transcriptome analysis demonstrated that many of the genes encoding these predicted traits are highly expressed under relevant physiological conditions. This is the first report to identify, through various genomic approaches, specific genetic adaptations of a Bifidobacterium taxon, Bifidobacterium dentium Bd1, to a lifestyle as a cariogenic microorganism in the oral cavity. In silico analysis and comparative genomic hybridization experiments clearly reveal a high level of genome conservation among various B. dentium strains. The data indicate that the genome of this opportunistic cariogen has evolved through a very limited number of horizontal gene acquisition events, highlighting the narrow boundaries that separate commensals from opportunistic pathogens

Occupational therapy: willard & spackmans

xxxiv, 1262 hlm. . ; ill. ; 26 cm

Invisible landscapes. Winds, experience and memory in Japanese coastal fishery

Drawing on a series of ethnographic cases of some fishing communities, the article explores the role of meteorological winds in Japanese coastal fisheries. In particular, it is argued that Japanese fishermen's ecological knowledge is strictly connected to memory that coexists with other institutional knowledge, such as meteorology, in a complex scenario of contestation and negotiation. The article stresses also the idea that fishermen's memory is implicitly subversive to the dominant native discourses on knowledge proposed by Japanese folklore studies, focused on its epistemological hierarchization (folk and scientific knowledge), or on the individualization of the intergenerational discrepancies between traditional and contemporary knowledge. It will attempt to show how the method of interpretation traditionally adopted by this academic discipline offers a vision of fishermen's ecological knowledge that is more susceptible to local and static evocations, and which is far from reflecting the complex relationship between coastal fisheries, memory and knowledge