| 1. |
- Faulwetter, Jennifer L, et al.
(författare)
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Microbial processes influencing performance of treatment wetlands : A review
- 2009
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Ingår i: ECOLOGICAL ENGINEERING. - : Elsevier BV. - 0925-8574. ; 35:6, s. 987-1004
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Tidskriftsartikel (refereegranskat)abstract
- This review summarizes the microbial mechanisms responsible for removal of carbon, nitrogen. and sulfur compounds in treatment wetlands (TWs) and identifies, categorizes and compares various techniques, from plate count to more modern genomic methods used to elucidate these mechanisms. Removal of a particular pollutant is typically associated with a specific microbial functional group, therefore employment of design and operational methodologies that enhance the activity of that group will better optimize performance. Redox condition is a manipulable parameter that can be used to optimize growth of a targeted functional group, therefore factors influencing the TW redox condition and its influence on organic carbon removal mechanisms are emphasized. Environmental factors influencing growth and activity of N and S cycling microbes (including temperature, pH, salinity, plant species selection and availability of organic carbon and/or inhibiting substances) are discussed with particular attention to factors that might be manipulated. This information is used to offer design and operational methodologies that might enhance growth of a desirable microbial functional group and project what additional microbially-focused research is required to better optimize TW performance.
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| 2. |
- Richards, Stephen, et al.
(författare)
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Genome Sequence of the Pea Aphid Acyrthosiphon pisum
- 2010
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:2, s. e1000313-
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Tidskriftsartikel (refereegranskat)abstract
- Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.
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