388 research outputs found

    Abundant Trimethylornithine Lipids and Specific Gene Sequences Are Indicative of Planctomycete Importance at the Oxic/Anoxic Interface in <i>Sphagnum</i>-Dominated Northern Wetlands

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    Northern wetlands make up a substantial terrestrial carbon sink and are often dominated by decay-resistant Sphagnum mosses.Recent studies have shown that planctomycetes appear to be involved in degradation of Sphagnum-derived debris. Novel trimethylornithine(TMO) lipids have recently been characterized as abundant lipids in various Sphagnum wetland planctomyceteisolates, but their occurrence in the environment has not yet been confirmed. We applied a combined intact polar lipid (IPL) andmolecular analysis of peat cores collected from two northern wetlands (Saxnäs Mosse [Sweden] and Obukhovskoye [Russia]) inorder to investigate the preferred niche and abundance of TMO-producing planctomycetes. TMOs were present throughout theprofiles of Sphagnum bogs, but their concentration peaked at the oxic/anoxic interface, which coincided with a maximum abundanceof planctomycete-specific 16S rRNA gene sequences. The sequences detected at the oxic/anoxic interface were affiliatedwith the Isosphaera group, while sequences present in the anoxic peat layers were related to an uncultured planctomycete group.Pyrosequencing-based analysis identified Planctomycetes as the major bacterial group at the oxic/anoxic interface at the Obukhovskoyepeat (54% of total 16S rRNA gene sequence reads), followed by Acidobacteria (19% reads), while in the Saxnäs Mossepeat, Acidobacteria were dominant (46%), and Planctomycetes contributed to 6% of the total reads. The detection of abundantTMO lipids in planctomycetes isolated from peat bogs and the lack of TMO production by cultures of acidobacteria suggest thatplanctomycetes are the producers of TMOs in peat bogs. The higher accumulation of TMOs at the oxic/anoxic interface and thechange in the planctomycete community with depth suggest that these IPLs could be synthesized as a response to changing redoxconditions at the oxic/anoxic interface

    Books

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    Oral cancer Oral Cancer: Epidemiology, Etiology and Pathology. Ed. by Colin Smith, Jens Pindborg and W. H. Binnie. Pp. ix + 106. Illustrated. R183,30. USA: Hemisphere. 1990.HPV and cervical cancer Human Papillomavirus and Cervical Cancer. Ed. by N. Munoz, F. X. Bosch and O. M. Jensen. Pp. xii + 155. Illustrated. France: International Agency for Research on Cancer. 1989.Child health Child Health in a Multicultural Society. Ed. by John Black. Pp. 75. Illustrated. £7 (including postage). London: BMJ. 1989. (Available also from Libriger Book Distributors).Merck manual of geriatics Merck Manual of Geriatrics. Ed. by William B. Abrams The Andrew J. Fletcher. Pp. xxii + 1267. Illustrated. RI4,50. and I: Merck. 1990. USALiver disease Progress in Liver Diseases. Vol 9. Ed. by Hans Popper and Fenton Schaffner. Pp. xv + 750. Illustrated. RllO. England: Harcourt Brace Jovanovich. 1990.Clinical dietetics and nutrition Clinical Dietetics and Nutrition. 3rd ed. Ed. by F. P. Antia. Pp. xvi +438. Illustrated. Oxford: Oxford University Press. 1989.Atlas of human anatomy Wolf-Heidegger's Atlas of Human Anatomy. Ed. by H. F. Frick, B. Kummer and R. V. Putz. pp. viii + 599. £(j(J. Basel: Karger. 1990.Health system decentralisation Health System Decentralization. Ed. by A. Mills, J. P. Vaughan, D. L. Smith and I. Tabibzadcll. pp. 151. Illustrated. SFr. 26. Geneva: World Health Organisation. 1990.Handbook of occupational medicine Handbook of Occupational Medicine. Ed. by Robert J. McCunney. Pp. xxiii + 510. Illustrated. Boston: Little, Brown. 1988.Leukaemia Leukaemia. 5th ed. Ed. by Edward S. Henderson and T. Andrew Lister. Pp. vii + 821. Illustrated. RHO. Kent: Harcoun Brace Jovanovich. 1990

    Python game design for children: Games and programming resources

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    This project is focused on helping middle and high school students learn how to program and think computationally. We are creating a set of resources that will be used by the students to understand programming, Python, and PyGames concepts. These resources will be used for teaching the two one-week summer camps through Clemson University\u27s Pre-Collegiate programs in June and July 2014. This camp has been offered at Georgia Tech and Clemson University for two summers using a drag and drop visual programming language to help students create games. The instructors have found that the camp attendees do not find the visual programming language to be challenging enough. Thus, we are designing curricula to teach introductory computing concepts with the Python and PyGames programming languages in a fun and creative way and to give students the opportunity to learn to design and program their own games. We are also designing and creating our own games as a way to learn the language and have examples for the kids in the camp to build upon. This project was initiated this semester and we will pilot resources this summer during the two weeks of camp. We will showcase the initial games and resources created for this project

    Carbon-isotope discrimination by leaves of Flaveria species exhibiting different amounts of C 3 -and C 4 -cycle co-function

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    Carbon-isotope ratios were examined as δ 13 C values in several C 3 , C 4 , and C 3 −C 4 Flaveria species, and compared to predicted δ 13 C, values generated from theoretical models. The measured δ 13 C values were within 4‰ of those predicted from the models. The models were used to identify factors that contribute to C 3 -like δ 13 C values in C 3 −C 4 species that exhibit considerable C 4 -cycle activity. Two of the factors contributing to C 3 -like δ 13 C values are high CO 2 leakiness from the C 4 pathway and pi/pa values that were higher than C 4 congeners. A marked break occurred in the relationship between the percentage of atmospheric CO 2 assimilated through the C 4 cycle and the δ 13 C value. Below 50% C 4 -cycle assimialtion there was no significant relationship between the variables, but above 50% the δ 13 C values became less negative. These results demonstrate that the level of C 4 -cycle expression can increase from, 0 to 50% with little integration of carbon transfer from the C 4 to the C 3 cycle. As expression increaces above 50%, however, increased integration of C 3 - and C 4 -cycle co-function occurs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47473/1/425_2004_Article_BF00394765.pd

    The \u3cem\u3eChlamydomonas\u3c/em\u3e Genome Reveals the Evolution of Key Animal and Plant Functions

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    Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the ∼120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella

    The six-minute walk test in community dwelling elderly: influence of health status.

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    BACKGROUND: The 6 minutes walk test (6MWT) is a useful assessment instrument for the exercise capacity of elderly persons. The impact of the health status on the 6MWT-distance in elderly, however, remains unclear, reducing its value in clinical settings. The objective of this study was to investigate to what extent the 6MWT-distance in community dwelling elderly is determined by health conditions. METHODS: One hundred and fifty-six community dwelling elderly people (53 male, 103 female) were assessed for health status and performed the 6MWT. After clinical evaluation, electrocardiography and laboratory examination participants were categorized into a stratified six-level classification system according to their health status, going from A (completely healthy) to D (signs of active disease at the moment of examination). RESULTS: The mean 6MWT-distance was 603 m (SD = 178). The 6MWT-distance decreased significantly with increasing age (ANOVA p = 0.0001) and with worsening health status (ANCOVA, corrected for age p < 0.001). A multiple linear regression model with health status, age and gender as independent variables explained 31% of the 6MWT-distance variability. Anthropometrical measures (stature, weight and BMI) did not significantly improve the prediction model. A significant relationship between 6MWT-distance and stature was only present in category A (completely healthy). CONCLUSIONS: Significant differences in 6MWT-distance are observed according to health status in community-dwelling elderly persons. The proposed health categorizing system for elderly people is able to distinguish persons with lower physical exercise capacity and can be useful when advising physical trainers for seniors

    Free-standing polyelectrolyte membranes made of chitosan and alginate

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    Free-standing films have increasing applications in the biomedical field as drug delivery systems for wound healing and tissue engineering. Here, we prepared free-standing membranes by the layer-by-layer assembly of chitosan and alginate, two widely used biomaterials. Our aim was to produce a thick membrane and to study the permeation of model drugs and the adhesion of muscle cells. We first defined the optimal growth conditions in terms of pH and alginate concentration. The membranes could be easily detached from polystyrene or polypropylene substrate without any postprocessing step. The dry thickness was varied over a large range from 4 to 35 μm. A 2-fold swelling was observed by confocal microscopy when they were immersed in PBS. In addition, we quantified the permeation of model drugs (fluorescent dextrans) through the free-standing membrane, which depended on the dextran molecular weight. Finally, we showed that myoblast cells exhibited a preferential adhesion on the alginate-ending membrane as compared to the chitosan-ending membrane or to the substrate side.This work was financially supported by Foundation for Science and Technology (FCT) through the Scholarship SFRH/BD/64601/2009 granted to S.G.C. C.M. is indebted to Grenoble INP for financial support via a postdoctoral fellowship. This work was supported by the European Commission (FP7 Program) via a European Research Council starting grant (BIOMIM, GA 259370 to C.P.). C.P. is also grateful to Institut Universitaire de France and to Grenoble Institute of Technology for financial support. We thank Isabelle Paintrand for her technical help with the confocal apparatus and Patrick Chaudouet for his help with SEM imaging
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