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61.
Sutherland WJ Aveling R Bennun L Chapman E Clout M Côté IM Depledge MH Dicks LV Dobson AP Fellman L Fleishman E Gibbons DW Keim B Lickorish F Lindenmayer DB Monk KA Norris K Peck LS Prior SV Scharlemann JP Spalding M Watkinson AR 《Trends in ecology & evolution》2012,27(1):12-18
Our aim in conducting annual horizon scans is to identify issues that, although currently receiving little attention, may be of increasing importance to the conservation of biological diversity in the future. The 15 issues presented here were identified by a diverse team of 22 experts in horizon scanning, and conservation science and its application. Methods for identifying and refining issues were the same as in two previous annual scans and are widely transferable to other disciplines. The issues highlight potential changes in climate, technology and human behaviour. Examples include warming of the deep sea, increased cultivation of perennial grains, burning of Arctic tundra, and the development of nuclear batteries and hydrokinetic in-stream turbines. 相似文献
62.
Plant and Soil - Multiple functions in the human body are affected by zinc deficiency. Here the etiology, assessment, health consequences, and intervention strategies for human zinc deficiency are... 相似文献
63.
Males in many taxa are known to exhibit behavioural plasticity in response to the perceived intensity of sperm competition, reflected in Drosophila melanogaster by increased copulation duration following prior exposure to a rival. We tested the prediction that males do not adjust their copulation effort in response to the presence of a competitor in Drosophila species where there is little or no sperm competition. Contrary to expectations, male plasticity in copulation duration was found in both Drosophila subobscura and Drosophila acanthoptera, species in which females rarely remate. These results are discussed in relation to the adaptive basis of plasticity in these species. 相似文献
64.
Govada L Carpenter L da Fonseca PC Helliwell JR Rizkallah P Flashman E Chayen NE Redwood C Squire JM 《Journal of molecular biology》2008,378(2):387-397
C-protein is a major component of skeletal and cardiac muscle thick filaments. Mutations in the gene encoding cardiac C-protein [cardiac myosin binding protein-C (cMyBP-C)] are one of the principal causes of hypertrophic cardiomyopathy. cMyBP-C is a string of globular domains including eight immunoglobulin-like and three fibronectin-like domains termed C0-C10. It binds to myosin and titin, and probably to actin, and may have both a structural and a regulatory role in muscle function. To help to understand the pathology of the known mutations, we have solved the structure of the immunoglobulin-like C1 domain of MyBP-C by X-ray crystallography to a resolution of 1.55 Å. Mutations associated with hypertrophic cardiomyopathy are clustered at one end towards the C-terminus, close to the important C1C2 linker, where they alter the structural integrity of this region and its interactions. 相似文献
65.
Ferree ED Dickinson JL Kleiber D Stern CA Haydock J Stanback MT Schmidt V Eisenberg L Stolzenburg C 《Molecular ecology resources》2008,8(6):1348-1350
Western and eastern bluebirds (Sialia mexicana and S. sialis) are socially monogamous passerines that engage in extra‐pair copulations. We obtained microsatellites from S. mexicana and optimized and characterized 15 microsatellite DNA loci in 60 individuals of this species. Primer pairs yielded an average of 13 alleles per locus in western bluebirds (range 3–35 alleles) with an average observed heterozygosity of 0.68 (range 0.27–0.88). All 15 loci also successfully amplified in S. sialis (n = 24), with an average of 11.5 alleles per locus (range 4–26) and an average observed heterozygosity of 0.59 (range 0.22–0.90). 相似文献
66.
Sequential actions of Pax3 and Pax7 drive xanthophore development in zebrafish neural crest 总被引:1,自引:0,他引:1
The Pax3/7 gene family has a fundamental and conserved role during neural crest formation. In people, PAX3 mutation causes Waardenburg syndrome, and murine Pax3 is essential for pigment formation. However, it is unclear exactly how Pax3 functions within the neural crest. Here we show that pax3 is expressed before other pax3/7 members, including duplicated pax3b, pax7 and pax7b genes, early in zebrafish neural crest development. Knockdown of Pax3 protein by antisense morpholino oligonucleotides results in defective fate specification of xanthophores, with complete ablation in the trunk. Other pigment lineages are specified and differentiate. As a consequence of xanthophore loss, expression of pax7, a marker of the xanthophore lineage, is reduced in neural crest. Morpholino knockdown of Pax7 protein shows that Pax7 itself is dispensable for xanthophore fate specification, although yellow pigmentation is reduced. Loss of xanthophores after reduction of Pax3 correlates with a delay in melanoblast differentiation followed by significant increase in melanophores, suggestive of a Pax3-driven fate switch within a chromatophore precursor or stem cell. Analysis of other neural crest derivatives reveals that, in the absence of Pax3, the enteric nervous system is ablated from its inception. Therefore, Pax3 in zebrafish is required for specification of two specific lineages of neural crest, xanthophores and enteric neurons. 相似文献
67.
Frederique Ponchel Robert J Verburg Sarah J Bingham Andrew K Brown John Moore Andrew Protheroe Kath Short Catherine A Lawson Ann W Morgan Mark Quinn Maya Buch Sarah L Field Sarah L Maltby Aurelie Masurel Susan H Douglas Liz Straszynski Ursula Fearon Douglas J Veale Poulam Patel Dennis McGonagle John Snowden Alexander F Markham David Ma Jacob M van Laar Helen A Papadaki Paul Emery John D Isaacs 《Arthritis research & therapy》2004,7(1):1-13
We previously demonstrated prolonged, profound CD4+ T-lymphopenia in rheumatoid arthritis (RA) patients following lymphocyte-depleting therapy. Poor reconstitution could result either from reduced de novo T-cell production through the thymus or from poor peripheral expansion of residual T-cells. Interleukin-7 (IL-7) is known to stimulate the thymus to produce new T-cells and to allow circulating mature T-cells to expand, thereby playing a critical role in T-cell homeostasis. In the present study we demonstrated reduced levels of circulating IL-7 in a cross-section of RA patients. IL-7 production by bone marrow stromal cell cultures was also compromised in RA. To investigate whether such an IL-7 deficiency could account for the prolonged lymphopenia observed in RA following therapeutic lymphodepletion, we compared RA patients and patients with solid cancers treated with high-dose chemotherapy and autologous progenitor cell rescue. Chemotherapy rendered all patients similarly lymphopenic, but this was sustained in RA patients at 12 months, as compared with the reconstitution that occurred in cancer patients by 3–4 months. Both cohorts produced naïve T-cells containing T-cell receptor excision circles. The main distinguishing feature between the groups was a failure to expand peripheral T-cells in RA, particularly memory cells during the first 3 months after treatment. Most importantly, there was no increase in serum IL-7 levels in RA, as compared with a fourfold rise in non-RA control individuals at the time of lymphopenia. Our data therefore suggest that RA patients are relatively IL-7 deficient and that this deficiency is likely to be an important contributing factor to poor early T-cell reconstitution in RA following therapeutic lymphodepletion. Furthermore, in RA patients with stable, well controlled disease, IL-7 levels were positively correlated with the T-cell receptor excision circle content of CD4+ T-cells, demonstrating a direct effect of IL-7 on thymic activity in this cohort. 相似文献
68.
69.
A considerable weight of evidence has accumulated to show that O2 diffusion
into legume nodules is controlled by a variable physical barrier which
balances the influx of this gas against its respiratory consumption.
Recently, however, the existence of such a barrier has been challenged on
the grounds of lack of evidence for structural changes and on the
possibility that there are metabolic and/or biochemical alternatives which
might substitute for the barrier. Such speculation may be justified for the
apparent diffusion resistance to O2 and CO2 where a range of potential
metabolic reactions make is difficult to separate physical and chemical
processes. However, this ambiguity does not apply to H2 within nodules
formed by rhizobium strains lacking an uptake hydrogenase
(Hup-ve). Within such nodules H2 generated as a
by-product of N2 fixation cannot be further metabolized. Thus the
steady-state relationship between internal concentration of H2 and its rate
of efflux from the nodule can only be determined by the resistance of a
physical barrier to diffusion. Data are presented here on H2 concentrations
and rates of efflux from nodules of soyabean (Clarke/USDA16 symbiosis)
subjected to detopping and stepped increases in pO2,
which provides incontrovertible evidence for the existence of such a
variable physical barrier. 相似文献
70.
Samuel García Myriam Liz Juan J Gómez-Reino Carmen Conde 《Arthritis research & therapy》2010,12(1):R33