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991.
Nadia I. Maaroufi Annika Nordin Kristin Palmqvist Niles J. Hasselquist Benjamin Forsmark Nicholas P. Rosenstock Hkan Wallander Michael J. Gundale 《Global Change Biology》2019,25(9):2900-2914
There is evidence that anthropogenic nitrogen (N) deposition enhances carbon (C) sequestration in boreal forest soils. However, it is unclear how free‐living saprotrophs (bacteria and fungi, SAP) and ectomycorrhizal (EM) fungi responses to N addition impact soil C dynamics. Our aim was to investigate how SAP and EM communities are impacted by N enrichment and to estimate whether these changes influence decay of litter and humus. We conducted a long‐term experiment in northern Sweden, maintained since 2004, consisting of ambient, low N additions (0, 3, 6, and 12 kg N ha?1 year?1) simulating current N deposition rates in the boreal region, as well as a high N addition (50 kg N ha?1 year?1). Our data showed that long‐term N enrichment impeded mass loss of litter, but not of humus, and only in response to the highest N addition treatment. Furthermore, our data showed that EM fungi reduced the mass of N and P in both substrates during the incubation period compared to when only SAP organisms were present. Low N additions had no effect on microbial community structure, while the high N addition decreased fungal and bacterial biomasses and altered EM fungi and SAP community composition. Actinomycetes were the only bacterial SAP to show increased biomass in response to the highest N addition. These results provide a mechanistic understanding of how anthropogenic N enrichment can influence soil C accumulation rates and suggest that current N deposition rates in the boreal region (≤12 kg N ha?1 year?1) are likely to have a minor impact on the soil microbial community and the decomposition of humus and litter. 相似文献
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《Current biology : CB》2019,29(11):1854-1865.e5
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Parasites are one of the strongest selective agents in nature. They select for hosts that evolve counter‐adaptive strategies to cope with infection. Helminth parasites are special because they can modulate their hosts’ immune responses. This phenomenon is important in epidemiological contexts, where coinfections may be affected. How different types of hosts and helminths interact with each other is insufficiently investigated. We used the three‐spined stickleback (Gasterosteus aculeatus) – Schistocephalus solidus model to study mechanisms and temporal components of helminth immune modulation. Sticklebacks from two contrasting populations with either high resistance (HR) or low resistance (LR) against S. solidus, were individually exposed to S. solidus strains with characteristically high growth (HG) or low growth (LG) in G. aculeatus. We determined the susceptibility to another parasite, the eye fluke Diplostomum pseudospathaceum, and the expression of 23 key immune genes at three time points after S. solidus infection. D. pseudospathaceum infection rates and the gene expression responses depended on host and S. solidus type and changed over time. Whereas the effect of S. solidus type was not significant after three weeks, T regulatory responses and complement components were upregulated at later time points if hosts were infected with HG S. solidus. HR hosts showed a well orchestrated immune response, which was absent in LR hosts. Our results emphasize the role of regulatory T cells and the timing of specific immune responses during helminth infections. This study elucidates the importance to consider different coevolutionary trajectories and ecologies when studying host‐parasite interactions. 相似文献
995.
《Bioorganic & medicinal chemistry letters》2019,29(16):2016-2024
Cytochromes P450 (CYPs) play an important role in the metabolism of endogenic and xenobiotic substances, especially drugs. In addition, many CYPs may serve as targets for disease treatment. However, due to the presence of a common heme, the hydrophobicity of the CYP binding cavity, and the high homology within the binding pocket, most CYP inhibitors lack selectivity, which often leads to drug-drug interactions. Therefore, it is meaningful to develop highly selective CYP inhibitors. In this review, we summarize some of the strategies that have been used to develop highly selective CYP inhibitors, such as the weakening of the heme-binding group interaction, reduction of molecular lipophilicity and introduction of small structural changes within compounds. 相似文献
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Barbara Tllez‐Robledo Concepcion Manzano Angela Saez Sara Navarro‐Neila Javier Silva‐Navas Laura de Lorenzo Mary‐Paz Gonzlez‐García Ren Toribio Arthur G. Hunt Roberto Baigorri Ilda Casimiro Siobhan M. Brady M. Mar Castellano J. Carlos del Pozo 《The Plant journal : for cell and molecular biology》2019,99(6):1203-1219