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991.
Manfred Türke Eric Heinze Kerstin Andreas Sarah M. Svendsen Martin M. Gossner Wolfgang W. Weisser 《Oecologia》2010,163(3):681-693
In beech-dominated forests in Central Europe, many spring geophytes show adaptations to seed dispersal by ants (myrmecochory). Ants, however, can be rare in such moist forests. Motivated by observations of slug feeding on seeds we investigated the seed consumption of two plant species, Anemone nemorosa and Asarum europaeum, by slugs, in a series of experiments. In a seed predation experiment in a beech forest, we found that seed removal was strongly reduced when gastropods were excluded from the seed depots. The contribution of insects, including ants, and rodents to seed removal was relatively less but differed between May and July. In the laboratory, slug species, in particular Arion sp., consumed seeds of both plant species. Slugs either consumed the elaiosomes of seeds or swallowed seeds intact. Swallowed seeds were defecated undamaged and germinated as well as control seeds when buried overwinter, indicating the potential for seed dispersal by slugs. We also recovered seeds of myrmecochores in the faeces of several slugs caught in forests. In a slug release experiment in the forest, slugs moved up to 14.6 m (mean 4.4 m) in 15 h, which is the median gut passage time of seeds based on measurements made in the laboratory. We also found that when slug-defecated seeds were offered to rodents, these were less attractive than control seeds, suggesting that passage through the slug gut reduces seed predation risk. Our results demonstrate that slugs are significant consumers of elaiosomes or entire seeds of ant-dispersed plants and that they can function as seed dispersers of these plants. 相似文献
992.
Federico Martin Sarah Dailey A. Mark Settles 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,121(4):697-704
The genome sequence of the B73 maize inbred enables map-based cloning of genetic variants underlying phenotypes. In parallel
to sequencing efforts, multiple public mutagenesis resources are being developed predominantly in the W22 and B73 inbreds.
Efficient platforms to map mutants in these genetic backgrounds would aid molecular genetic analysis of the public resources.
We screened 505 simple sequence repeat markers for polymorphisms between the B73, Mo17, and W22 inbreds. Using common thermocycling
conditions, 47.1% of the markers showed co-dominant polymorphisms in at least one pair of inbreds. Based on these results,
we identified 85 distributed markers for mapping in all three inbred pairs. For each inbred pair, the distributed set has
64–71 polymorphic markers with a mean distance of 27–29 cM between markers. The distributed markers give nearly complete coverage
of the genetic map for each inbred pair. We demonstrate the utility of the marker set for efficient placement of mutants on
the maize genetic map with an example mapping experiment of a seed mutant from the UniformMu mutagenesis resource. We conclude
that these distributed molecular markers enable rapid mapping of phenotypic variants from public mutagenesis populations. 相似文献
993.
Benjamin C KirkupJr LeeAnn Chang Sarah Chang Dirk Gevers Martin F Polz 《BMC microbiology》2010,10(1):137
Background
While most gamma proteobacteria have a single circular chromosome, Vibrionales have two circular chromosomes. Horizontal gene transfer is common among Vibrios, and in light of this genetic mobility, it is an open question to what extent the two chromosomes themselves share a common history since their formation. 相似文献994.
Djabarouti S Breilh D Duffau P Lazaro E Greib C Caubet O Saux MC Pellegrin JL Viallard JF 《Arthritis research & therapy》2010,12(6):R217
Introduction
The aim of this study was to determine whether mycophenolate mofetil (MMF) pharmacokinetics (PK) under combined MMF and prednisone remission-maintenance therapy can predict systemic lupus erythematosus (SLE) clinical flares. 相似文献995.
Charlotte E Page Shaun Smale Sara M Carty Nicholas Amos Sarah N Lauder Rhian M Goodfellow Peter J Richards Simon A Jones Nicholas Topley Anwen S Williams 《Arthritis research & therapy》2010,12(2):R49
Introduction
The first few months after symptom onset represents a pathologically distinct phase in rheumatoid arthritis (RA). We used relevant experimental models to define the pathological role of interferon-γ (IFN-γ) during early inflammatory arthritis. 相似文献996.
Polymer conjugation increases an enzyme's circulation time and stability for use as a therapeutic agent, but this attachment indubitably affects its properties. Covalent attachment of multiple polyethylene glycol chains with sizes of either 2, 5, 10, or 20 kDa increases the molecular weight and hydrodynamic radius of the model enzyme trypsin. The sizes of these polymer-enzyme conjugates are increased to be within the recommended limits for PDEPT applications. The T(d) increases from 49 to 60 °C to expand the enzyme's workable range of conditions. This functionalization with PEG polymers of varying lengths maintains trypsin's enzymatic activity. Conjugate activities are 79-120% that of native trypsin at room temperature and 221-432% that of trypsin at 37 °C. 相似文献
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Anita B. Hjelmeland Qiulian Wu Sarah Wickman Christine Eyler John Heddleston Qing Shi Justin D. Lathia Jennifer MacSwords Jeongwu Lee Roger E. McLendon Jeremy N. Rich 《PLoS biology》2010,8(2)
Glioblastomas are deadly cancers that display a functional cellular hierarchy maintained by self-renewing glioblastoma stem cells (GSCs). GSCs are regulated by molecular pathways distinct from the bulk tumor that may be useful therapeutic targets. We determined that A20 (TNFAIP3), a regulator of cell survival and the NF-κB pathway, is overexpressed in GSCs relative to non-stem glioblastoma cells at both the mRNA and protein levels. To determine the functional significance of A20 in GSCs, we targeted A20 expression with lentiviral-mediated delivery of short hairpin RNA (shRNA). Inhibiting A20 expression decreased GSC growth and survival through mechanisms associated with decreased cell-cycle progression and decreased phosphorylation of p65/RelA. Elevated levels of A20 in GSCs contributed to apoptotic resistance: GSCs were less susceptible to TNFα-induced cell death than matched non-stem glioma cells, but A20 knockdown sensitized GSCs to TNFα-mediated apoptosis. The decreased survival of GSCs upon A20 knockdown contributed to the reduced ability of these cells to self-renew in primary and secondary neurosphere formation assays. The tumorigenic potential of GSCs was decreased with A20 targeting, resulting in increased survival of mice bearing human glioma xenografts. In silico analysis of a glioma patient genomic database indicates that A20 overexpression and amplification is inversely correlated with survival. Together these data indicate that A20 contributes to glioma maintenance through effects on the glioma stem cell subpopulation. Although inactivating mutations in A20 in lymphoma suggest A20 can act as a tumor suppressor, similar point mutations have not been identified through glioma genomic sequencing: in fact, our data suggest A20 may function as a tumor enhancer in glioma through promotion of GSC survival. A20 anticancer therapies should therefore be viewed with caution as effects will likely differ depending on the tumor type. 相似文献