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Manfred G Hofle - One of the best experts on this subject based on the ideXlab platform.
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flagellate predation on a bacterial model Community interplay of size selective grazing specific bacterial cell size and bacterial Community composition
Applied and Environmental Microbiology, 1999Co-Authors: Martin W Hahn, Manfred G HofleAbstract:The influence of grazing by the bacterivorous nanoflagellate Ochromonas sp. strain DS on the taxonomic and morphological structures of a complex bacterial Community was studied in one-stage chemostat experiments. A bacterial Community, consisting of at least 30 different strains, was fed with a complex carbon source under conditions of low growth rate (0.5 day−1 when nongrazed) and low substrate concentration (9 mg liter−1). Before and after the introduction of the predator, the bacterial Community composition was studied by in situ techniques (immunofluorescence microscopy and fluorescent in situ hybridization), as well as by cultivation on agar media. The cell sizes of nonspecifically stained and immunofluorescently labeled bacteria were measured by image analysis. Grazing by the flagellate caused a bidirectional change in the morphological structure of the Community. Medium-size bacterial cells, which dominated the nongrazed Community, were largely replaced by smaller cells, as well as by cells contained in large multicellular flocs. Cell morphological changes were combined with Community taxonomic changes. After introduction of the flagellate, the dominating strains with Medium-size cells were largely replaced by single-celled strains with smaller cells on the one hand and, on the other hand, by Pseudomonas sp. strain MWH1, which formed the large, floc-like forms. We assume that size-selective grazing was the major force controlling both the morphological and the taxonomic structures of the model Community.
Martin W Hahn - One of the best experts on this subject based on the ideXlab platform.
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flagellate predation on a bacterial model Community interplay of size selective grazing specific bacterial cell size and bacterial Community composition
Applied and Environmental Microbiology, 1999Co-Authors: Martin W Hahn, Manfred G HofleAbstract:The influence of grazing by the bacterivorous nanoflagellate Ochromonas sp. strain DS on the taxonomic and morphological structures of a complex bacterial Community was studied in one-stage chemostat experiments. A bacterial Community, consisting of at least 30 different strains, was fed with a complex carbon source under conditions of low growth rate (0.5 day−1 when nongrazed) and low substrate concentration (9 mg liter−1). Before and after the introduction of the predator, the bacterial Community composition was studied by in situ techniques (immunofluorescence microscopy and fluorescent in situ hybridization), as well as by cultivation on agar media. The cell sizes of nonspecifically stained and immunofluorescently labeled bacteria were measured by image analysis. Grazing by the flagellate caused a bidirectional change in the morphological structure of the Community. Medium-size bacterial cells, which dominated the nongrazed Community, were largely replaced by smaller cells, as well as by cells contained in large multicellular flocs. Cell morphological changes were combined with Community taxonomic changes. After introduction of the flagellate, the dominating strains with Medium-size cells were largely replaced by single-celled strains with smaller cells on the one hand and, on the other hand, by Pseudomonas sp. strain MWH1, which formed the large, floc-like forms. We assume that size-selective grazing was the major force controlling both the morphological and the taxonomic structures of the model Community.
James Allen - One of the best experts on this subject based on the ideXlab platform.
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feasibility of a Community intervention for the prevention of suicide and alcohol abuse with yup ik alaska native youth the elluam tungiinun and yupiucimta asvairtuumallerkaa studies
American Journal of Community Psychology, 2014Co-Authors: Gerald V Mohatt, Carlotta Ching Ting Fok, David Henry, James AllenAbstract:The Elluam Tungiinun and Yupiucimta Asvairtuumallerkaa studies evaluated the feasibility of a Community intervention to prevent suicide and alcohol abuse among rural Yup’ik Alaska Native youth in two remote communities. The intervention originated in an Indigenous model of protection, and its development used a Community based participatory research process. Feasibility assessment aimed to assess the extent to which (1) the intervention could be implemented in rural Alaska Native communities, and (2) the intervention was capable of producing measurable effects. Scales maximally sensitive to change were derived from earlier measurement work, and the study contrasted implementation process and outcomes across the two communities. In one Community, Medium dose response effects (d = .30–.50), with dose defined as number of intervention activities attended, were observed in the growth of intermediate protective factors and ultimate variables. In the other Community, Medium dose effects were observed for one intermediate protective factor variable, and small dose effects were observed in ultimate variables. Differences across communities in resources supporting intervention explain these contrasting outcomes. Results suggest implementation in these rural Alaska settings is feasible when sufficient resources are available to sustain high levels of local commitment. In such cases, measureable effects are sufficient to warrant a prevention trial.
Gerald V Mohatt - One of the best experts on this subject based on the ideXlab platform.
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feasibility of a Community intervention for the prevention of suicide and alcohol abuse with yup ik alaska native youth the elluam tungiinun and yupiucimta asvairtuumallerkaa studies
American Journal of Community Psychology, 2014Co-Authors: Gerald V Mohatt, Carlotta Ching Ting Fok, David Henry, James AllenAbstract:The Elluam Tungiinun and Yupiucimta Asvairtuumallerkaa studies evaluated the feasibility of a Community intervention to prevent suicide and alcohol abuse among rural Yup’ik Alaska Native youth in two remote communities. The intervention originated in an Indigenous model of protection, and its development used a Community based participatory research process. Feasibility assessment aimed to assess the extent to which (1) the intervention could be implemented in rural Alaska Native communities, and (2) the intervention was capable of producing measurable effects. Scales maximally sensitive to change were derived from earlier measurement work, and the study contrasted implementation process and outcomes across the two communities. In one Community, Medium dose response effects (d = .30–.50), with dose defined as number of intervention activities attended, were observed in the growth of intermediate protective factors and ultimate variables. In the other Community, Medium dose effects were observed for one intermediate protective factor variable, and small dose effects were observed in ultimate variables. Differences across communities in resources supporting intervention explain these contrasting outcomes. Results suggest implementation in these rural Alaska settings is feasible when sufficient resources are available to sustain high levels of local commitment. In such cases, measureable effects are sufficient to warrant a prevention trial.
Carlotta Ching Ting Fok - One of the best experts on this subject based on the ideXlab platform.
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feasibility of a Community intervention for the prevention of suicide and alcohol abuse with yup ik alaska native youth the elluam tungiinun and yupiucimta asvairtuumallerkaa studies
American Journal of Community Psychology, 2014Co-Authors: Gerald V Mohatt, Carlotta Ching Ting Fok, David Henry, James AllenAbstract:The Elluam Tungiinun and Yupiucimta Asvairtuumallerkaa studies evaluated the feasibility of a Community intervention to prevent suicide and alcohol abuse among rural Yup’ik Alaska Native youth in two remote communities. The intervention originated in an Indigenous model of protection, and its development used a Community based participatory research process. Feasibility assessment aimed to assess the extent to which (1) the intervention could be implemented in rural Alaska Native communities, and (2) the intervention was capable of producing measurable effects. Scales maximally sensitive to change were derived from earlier measurement work, and the study contrasted implementation process and outcomes across the two communities. In one Community, Medium dose response effects (d = .30–.50), with dose defined as number of intervention activities attended, were observed in the growth of intermediate protective factors and ultimate variables. In the other Community, Medium dose effects were observed for one intermediate protective factor variable, and small dose effects were observed in ultimate variables. Differences across communities in resources supporting intervention explain these contrasting outcomes. Results suggest implementation in these rural Alaska settings is feasible when sufficient resources are available to sustain high levels of local commitment. In such cases, measureable effects are sufficient to warrant a prevention trial.