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991.
Aphids are insects that cause direct damage to crops by the removal of phloem sap, but more importantly they spread devastating viruses. Aphids use their sophisticated mouthpart (i.e. stylet) to feed from the phloem sieve elements of the host plant. To identify genes that affect host plant resistance to aphids, we previously screened an Arabidopsis thaliana activation tag mutant collection. In such mutants, tagged genes are overexpressed by a strong 35S enhancer adjacent to the natural promoter, resulting in a dominant gain-of-function phenotype. We previously identified several of these mutants on which the aphid Myzus persicae showed a reduced population development compared with wild type. In the present study we show that the gene responsible for the phenotype of one of the mutants is At5g65040 and named this gene Increased Resistance to Myzus persicae 1 (IRM1). Overexpression of the cloned IRM1 gene conferred a phenotype identical to that of the original mutant. Conversely, an IRM1 knockout mutant promoted aphid population development compared to the wild type. We performed Electrical Penetration Graph analysis to investigate how probing and feeding behaviour of aphids was affected on plants that either overexpressed IRM1 or contained a knockout mutation in this gene. The EPG results indicated that the aphids encounter resistance factors while reaching for the phloem on the overexpressing line. This resistance mechanism also affected other aphid species and is suggested to be of mechanical nature. Interestingly, genetic variation for IRM1 expression in response to aphid attack was observed. Upon aphid attack the expression of IRM1 was initially (after 6 hours) induced in ecotype Wassilewskija followed by suppression. In Columbia-0, IRM1 expression was already suppressed six hours after the start of the infestation. The resistance conferred by the overexpression of IRM1 in A. thaliana trades off with plant growth. 相似文献
992.
993.
Nathalie Doerflinger Catherine Linder Karim Ouahchi Gabor Gyapay Jean Weissenbach Denis Le Paslier Philippe Rigault Samir Belal Christiane Ben Hamida Faycal Hentati Mongi Ben Hamida Massimo Pandolfo Stephano DiDonato Ronald Sokol Herbert Kayden Pierre Landrieu Alexandra Durr Alexis Brice Fran?oise Goutières Alfried Kohlschütter Pascal Sabouraud Ali Benomar Mohamed Yahyaoui Jean-Louis Mandel Michel Koenig 《American journal of human genetics》1995,56(5):1116-1124
Ataxia with vitamin E deficiency (AVED) is an autosomal recessive disease characterized clinically by neurological symptoms with often striking resemblance to those of Friedreich ataxia. This disorder has been reported previously as familial isolated vitamin E deficiency. We have mapped recently the AVED locus to a 5-cM confidence interval on chromosome 8q by homozygosity mapping in six Mediterranean families. We have now analyzed six new and two previously described families and demonstrate genetic homogeneity despite important clinical variability and wide geographic origins. Analysis of nine new tightly linked microsatellite markers, including four characterized in this study, revealed a predominant but not unique mutation in northern African populations, where this condition is more frequent. Haplotype analysis but also classical recombinations allowed us to refine the AVED position to a 1-cM interval. A YAC contig over this interval was constructed from marker STSs and YAC fingerprint data, in order to facilitate the search of the AVED gene. 相似文献
994.
Increased sequence diversity coverage improves detection of HIV-specific T cell responses 总被引:2,自引:0,他引:2
Frahm N Kaufmann DE Yusim K Muldoon M Kesmir C Linde CH Fischer W Allen TM Li B McMahon BH Faircloth KL Hewitt HS Mackey EW Miura T Khatri A Wolinsky S McMichael A Funkhouser RK Walker BD Brander C Korber BT 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(10):6638-6650
The accurate identification of HIV-specific T cell responses is important for determining the relationship between immune response, viral control, and disease progression. HIV-specific immune responses are usually measured using peptide sets based on consensus sequences, which frequently miss responses to regions where test set and infecting virus differ. In this study, we report the design of a peptide test set with significantly increased coverage of HIV sequence diversity by including alternative amino acids at variable positions during the peptide synthesis step. In an IFN-gamma ELISpot assay, these "toggled" peptides detected HIV-specific CD4(+) and CD8(+) T cell responses of significantly higher breadth and magnitude than matched consensus peptides. The observed increases were explained by a closer match of the toggled peptides to the autologous viral sequence. Toggled peptides therefore afford a cost-effective and significantly more complete view of the host immune response to HIV and are directly applicable to other variable pathogens. 相似文献
995.
996.
Marc van Bilsen Anneleen Daniels Olaf Brouwers Ben J. A. Janssen Wouter J. A. Derks Agnieszka E. Brouns Chantal Munts Casper G. Schalkwijk Ger J. van der Vusse Frans A. van Nieuwenhoven 《PloS one》2014,9(1)
Background
Type 2 diabetes is frequently associated with co-morbidities, including hypertension. Here we investigated if hypertension is a critical factor in myocardial remodeling and the development of cardiac dysfunction in type 2 diabetic db/db mice.Methods
Thereto, 14-wks-old male db/db mice and non-diabetic db/+ mice received vehicle or angiotensin II (AngII) for 4 wks to induce mild hypertension (n = 9–10 per group). Left ventricular (LV) function was assessed by serial echocardiography and during a dobutamine stress test. LV tissue was subjected to molecular and (immuno)histochemical analysis to assess effects on hypertrophy, fibrosis and inflammation.Results
Vehicle-treated diabetic mice neither displayed marked myocardial structural remodeling nor cardiac dysfunction. AngII-treatment did not affect body weight and fasting glucose levels, and induced a comparable increase in blood pressure in diabetic and control mice. Nonetheless, AngII-induced LV hypertrophy was significantly more pronounced in diabetic than in control mice as assessed by LV mass (increase +51% and +34%, respectively, p<0.01) and cardiomyocyte size (+53% and +31%, p<0.001). This was associated with enhanced LV mRNA expression of markers of hypertrophy and fibrosis and reduced activation of AMP-activated protein kinase (AMPK), while accumulation of Advanced Glycation End products (AGEs) and the expression levels of markers of inflammation were not altered. Moreover, AngII-treatment reduced LV fractional shortening and contractility in diabetic mice, but not in control mice.Conclusions
Collectively, the present findings indicate that type 2 diabetes in its early stage is not yet associated with adverse cardiac structural changes, but already renders the heart more susceptible to hypertension-induced hypertrophic remodeling. 相似文献997.
Rep M Dekker HL Vossen JH de Boer AD Houterman PM de Koster CG Cornelissen BJ 《FEBS letters》2003,534(1-3):82-86
The coding sequence of a major xylem sap protein of tomato was identified with the aid of mass spectrometry. The protein, XSP10, represents a novel family of extracellular plant proteins with structural similarity to plant lipid transfer proteins. The XSP10 gene is constitutively expressed in roots and lower stems. The decline of XSP10 protein levels in tomato infected with a fungal vascular pathogen may reflect breakdown or modification by the pathogen. 相似文献
998.
Claudet J Osenberg CW Benedetti-Cecchi L Domenici P García-Charton JA Pérez-Ruzafa A Badalamenti F Bayle-Sempere J Brito A Bulleri F Culioli JM Dimech M Falcón JM Guala I Milazzo M Sánchez-Meca J Somerfield PJ Stobart B Vandeperre F Valle C Planes S 《Ecology letters》2008,11(5):481-489
Marine reserves are widely used throughout the world to prevent overfishing and conserve biodiversity, but uncertainties remain about their optimal design. The effects of marine reserves are heterogeneous. Despite theoretical findings, empirical studies have previously found no effect of size on the effectiveness of marine reserves in protecting commercial fish stocks. Using 58 datasets from 19 European marine reserves, we show that reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect. Moreover, positive effects of marine reserve on commercial fish species and species richness are linked to the time elapsed since the establishment of the protection scheme. The reserve size-dependency of the response to protection has strong implications for the spatial management of coastal areas because marine reserves are used for spatial zoning. 相似文献
999.
Adam Felton Joern Fischer David B. Lindenmayer Rebecca Montague-Drake Arianne R. Lowe Debbie Saunders Annika M. Felton Will Steffen Nicola T. Munro Kara Youngentob Jake Gillen Phil Gibbons Judsen E. Bruzgul Ioan Fazey Suzi J. Bond Carole P. Elliott Ben C. T. Macdonald Luciana L. Porfirio Martin Westgate Martin Worthy 《Biodiversity and Conservation》2009,18(8):2243-2253
Recent reviews of the conservation literature indicate that significant biases exist in the published literature regarding
the regions, ecosystems and species that have been examined by researchers. Despite the global threat of climatic change,
similar biases may be occurring within the sub-discipline of climate-change ecology. Here we hope to foster critical thought
and discussion by considering the directions taken by conservation researchers when addressing climate change. To form a quantitative
basis for our perspective, we assessed 248 papers from the climate change literature that considered the conservation management
of biodiversity and ecosystems. We found that roughly half of the studies considered climate change in isolation from other
threatening processes. We also found that the majority of surveyed scientific publications were conducted in the temperate
forests of Europe and North America. Regions such as Latin America that are rich in biodiversity but may have low adaptive
capacity to climate change were not well represented. We caution that such biases in research effort may be distracting our
attention away from vulnerable regions, ecosystems and species. Specifically we suggest that the under-representation of research
from regions low in adaptive capacity and rich in biodiversity requires international collaboration by those experienced in
climate-change research, with researchers from less wealthy nations who are familiar with local issues, ecosystems and species.
Furthermore, we caution that the propensity of ecologists to work in essentially unmodified ecosystems may fundamentally hamper
our ability to make useful recommendations in a world that is experiencing significant global change. 相似文献
1000.
Ibtissem Ben Amara Aida Karray Ahmed Hakim Yassine Ben Ali Afef Troudi Nejla Soudani Tahia Boudawara Khaled Mounir Zeghal Najiba Zeghal 《Biological trace element research》2013,156(1-3):230-242
Dimethoate (DM) is an organophosphate insecticide widely used in agriculture and industry and has toxic effects on non-target organisms especially mammalian. However, we still know little about DM-induced kidney injury and its alleviation by natural antioxidants. In the present study, selenium (Se), vitamin E, DM, Se+DM, vitamin E+DM, Se+vitamin E+DM were given to adult rats for 4 weeks. Plasma creatinine and uric acid, kidney MDA, PC, H2O2 and AOPP levels were higher, while Na+-K+-ATPase and LDH values were lower in the DM group than those of controls. A smear without ladder formation on agarose gel was shown in the DM group, indicating random DNA degradation and DM-induced genotoxicity. A decrease in kidney GSH, NPSH and plasma urea levels and an increase in GPx, SOD and catalase activities were observed in the DM group when compared to those of controls. Plasma cystatin C levels increased, indicating a decrease in glomerular filtration rate. When Se or vitamin E was added through diet, the biochemical parameters cited above were partially restored in Se+DM and vitamin E+DM than DM group. The joint effect of Se and vitamin E was more powerful against DM-induced oxidative stress and kidney dysfunction. The changes in biochemical parameters were substantiated by histological data. In conclusion, our results indicated a possible mechanism of DM-induced nephrotoxicity, where renal genotoxicity was noted, membrane-bound ATPases and plasma biomarkers were disturbed. Se and vitamin E ameliorated the toxic effects of this pesticide in renal tissue suggesting their role as potential antioxidants. 相似文献