Although rocks are habitable places for microbes in extreme environments, microbial diversity in these lithic environments is still poorly understood. The diversity and abundance of rock-inhabiting microbial communities in different types of rock in Svalbard, Norwegian High Arctic were examined using NGS sequencing of bacterial 16S rRNA genes and fungal 28S rRNA genes. Compositions of both bacterial and fungal communities varied across different rock types: sandstone, limestone, basalt, granite and travertine. Bacterial communities were dominated by Actinobacteria, Proteobacteria, Chloroflexi, Bacteroidetes and Acidobacteria. Fungal communities consisted of Eurotiomycetes, Lecanoromycetes, Dothideomycetes and Leotiomycetes. Both bacterial and fungal community compositions were significantly correlated with the geochemical characteristics of rocks. Bacterial communities were considerably correlated with the rock elements such as Mg and Ca. Fungal communities were considerably correlated with Fe. Interestingly, many dominant bacterial and fungal operational taxonomic units in the investigated rocks from the study area were closely affiliated to those found in other cold regions such as Alpine area, Arctic and Antarctica, suggesting that environmental constraints such as cold temperature may lead to convergence in microbial community composition. These results confirm that rocks in cold environments act as reservoirs of diverse bacteria and fungi, which may improve our understanding of lithic microbial ecology in the cold desert.
Although rocks are habitable places for microbes in extreme environments, microbial diversity in these lithic environments is still poorly understood. The diversity and abundance of rock-inhabiting microbial communities in different types of rock in Svalbard, Norwegian High Arctic were examined using NGS sequencing of bacterial 16S rRNA genes and fungal 28S rRNA genes. Compositions of both bacterial and fungal communities varied across different rock types: sandstone, limestone, basalt, granite and travertine. Bacterial communities were dominated by Actinobacteria, Proteobacteria, Chloroflexi, Bacteroidetes and Acidobacteria. Fungal communities consisted of Eurotiomycetes, Lecanoromycetes, Dothideomycetes and Leotiomycetes. Both bacterial and fungal community compositions were significantly correlated with the geochemical characteristics of rocks. Bacterial communities were considerably correlated with the rock elements such as Mg and Ca. Fungal communities were considerably correlated with Fe. Interestingly, many dominant bacterial and fungal operational taxonomic units in the investigated rocks from the study area were closely affiliated to those found in other cold regions such as Alpine area, Arctic and Antarctica, suggesting that environmental constraints such as cold temperature may lead to convergence in microbial community composition. These results confirm that rocks in cold environments act as reservoirs of diverse bacteria and fungi, which may improve our understanding of lithic microbial ecology in the cold desert.
Box 357136, Department of Pediatric Dentistry, School of Dentistry, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195-7136, USA. linjy@u.washington.edu
The purpose of this study was twofold: 1) to examine website content provided by U.S. and Canadian pediatric dentistry residency programs, and 2) to understand aspects of program websites that dental students report to be related to their interests. Sixty-eight program websites were reviewed by five interprofessional evaluators. A thirty-six-item evaluation form was organized into 1) program descriptive items listed on the American Academy of Pediatric Dentistry (AAPD) website (n=21); 2) additional program descriptive items not listed on the AAPD website but of interest (n=9); and 3) items related to website interface design (n=5). We also surveyed fifty-four dental students regarding their interest in various aspects of program descriptions. The results of this study suggest that pediatric dentistry residency programs in general tend to provide identical or less information than what is listed on the AAPD website. The majority of respondents (76 percent) reported that residency program websites would be their first source of information about advanced programs. The greatest gap between the available website information and students' interests exists in these areas: stipend and tuition information, state licensure, and program strengths. Pediatric dentistry residency programs underutilize websites as a marketing and recruitment tool and should incorporate more information in areas of students' priority interests.
Woodruff v. Covington--physicians associated with federally funded health-care programs may not be immune to claims brought under Federal Tort Claims Act.
