Strain CSC1T , a Gram-negative, aerobic, methane-oxidizing bacterium, was isolated from an uncontaminated aquifer nearly 20 years ago. Based on 16S rRNA gene sequence similarity, this strain was identified as a member of the Alphaproteobacteria, most closely related to an uncultured member of the Methylocystaceae as well as two cultured organisms, Species of the genus Methylocystis are strictly aerobic, Gram-negative bacteria that are able to grow on onecarbon compounds (e.g. methane or methanol) (Bowman et al., 1993). The genus Methylocystis belongs to the class Alphaproteobacteria and currently consists of three species with standing in nomenclature, Methylocystis parvus, Methylocystis echinoides and Methylocystis rosea (Whittenbury et al., 1970;Gal'chenko et al., 1977;Bowman et al., 1993; Wartainen et al., 2006). Numerous Methylocystis strains have been identified in a variety of environments, including lake, ocean, marsh and creek sediments and water, coal mine drainage water and the roots of plants (Whittenbury et al., 1970;Gal'chenko et al., 1977;Bowman et al., 1993;Hanson & Hanson, 1996;Calhoun & King, 1998;Heyer et al., 2002 (Stanley et al., 1983;Prior & Dalton, 1985;Choi et al., 2003;Wartiainen et al., 2006). Methylocystis parvus OBBP T and Methylocystis rosea SV97 T do not possess genes encoding sMMO (Tsien & Hanson, 1992;Lloyd et al., 1999;Wartiainen et al., 2006). The genera Methylocella and Methylocapsa are classified as type II methanotrophs; however, they possess morphological and Abbreviations: PHB, poly-b-hydroxybutyrate; pMMO, particulate methane mononoxygenase; sMMO, soluble methane monooxygenase; TEM, transmission electron microscopy. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequence and partial mxaF, mmoX and pmoA gene sequences of strain CSC1T are respectively DQ364433, DQ664499, DQ664498 and DQ364434.Neighbour-joining trees based on partial mmoX and mxaF gene sequences and results of electron microscope cytochemistry of the S-layer of strain CSC1T are available as supplementary material with the online version of this paper.

BackgroundSince students' success in their first-semester college mathematics course is a key factor in their success in engineering, many summer bridge programs for underrepresented students focus on their preparation in mathematics. However, research on the design and efficacy of such programs is limited. We examine the design and effectiveness of a modeling-based approach to mathematics for entering freshmen engineering students.Purpose The study addresses two questions: Does a modeling-based mathematics course in a bridge program positively affect students' performance in their first-semester college mathematics course? To what extent does a sequence of modeling tasks support the development of students' concepts of average rates of change?Design/Method This quasi-experimental study compared two cohorts of bridge program students over six years to examine the effectiveness of a modeling-based mathematics course on first-semester mathematics course grades. Pre-and post-tests measured changes in students' concepts of average rates of change. ResultsThe modeling-based mathematics course closed the previous letter grade gap between bridge program participants and non-participants in the first mathematics course. We also found significant course grade gains for students who took the modeling-based mathematics course compared with a previous cohort who took a traditional summer mathematics course.Conclusions These results suggest that the modeling-based mathematics course, with its focus on the development of engineering students' abilities to model changing phenomena, was effective in improving students' concepts of average rate of change and their firstsemester mathematics course grade.

Little is known about the community dynamics of fungi on decomposing fine roots, despite the importance of fine roots as a source of carbon to detrital systems in forests. We examined fungal communities on dead roots in a sugar-maple dominated northern hardwood forest to test the hypothesis that community development is sensitive to rhizosphere disruption. We generated cohorts of dead fine roots in root windows and disturbed the rhizosphere microbial community in half of the windows by moving roots into sieved bulk soil. We sampled root fragments repeatedly over time and cultured fungi from these fragments to explore temporal patterns of fungal species composition. Disturbing the root rhizosphere prior to initiating decomposition changed the dominant fungal taxa, the distribution of dominant species within the community, and the temporal development in the culturable fungal community. Dominance in control roots shifted from Neonectria in early decay to Umbelopsis in later decay. Disturbance roots were more evenly dominated over time by Trichoderma, Neonectria, another species of Umbelopsis, and Pochonia. Our results suggest that species interactions are important in the ecology of fine root decay fungi, with the rhizosphere community of the living root influencing development of the decay community.

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