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71.
Screening of cDNA libraries at low stringency and complete sequencing of EST clones with homology to thioredoxins allowed us to characterize five new prokaryotic type Arabidopsis thaliana thioredoxins. All present N-terminal extensions with characteristics of transit peptides. Four are clustered in a phylogenetic tree with the chloroplastic thioredoxin m from red and green algae and higher plants, and their transit peptides have typical characteristics of chloroplastic transit peptides. One is clearly divergent and defines a new prokaryotic thioredoxin type that we have named thioredoxin x. Its transit peptide sequence presents characteristics of both chloroplastic and mitochondrial transit peptides. The five corresponding genes are expressed at different levels, but mostly in green tissues and in in-vitro cultivated cells. 相似文献
72.
Increased isolation of two Biosphere Reserves and surrounding protected areas (WAP ecological complex, West Africa) 总被引:1,自引:0,他引:1
Nicola Clerici Antonio Bodini Hugh Eva Jean-Marie Grgoire Dominique Dulieu Carlo Paolini 《Journal for Nature Conservation》2007,15(1):26-40
Protected areas such as nature reserves have been found to be effective in preventing habitat destruction and protecting ecosystems within their borders. Recent studies however found extensive loss of tropical forest habitat around protected areas, vastly contributing to increase the levels of ecological isolation. Using high-resolution satellite data we investigated the isolation trend occurring in the W-Arly-Pendjari (WAP) ecological complex in West Africa. A land-cover change analysis was performed for the period 1984–2002: savanna vegetation extension and loss were derived within the complex and in a 30 km peripheral buffer. Sample regions in the buffer were also analysed using selected spatial indicators to quantify temporal trends in habitat fragmentation. Implications for change in relative capacity to conserve biodiversity were discussed through the calculation of the species richness capacity (SRC). More than 14.5% of savanna habitat was lost in the WAP peripheral areas, while 0.3% was converted inside the complex. The degree of fragmentation of remnant savanna habitat has also drastically increased. Despite the effectiveness of the park conservation programme, we found through the SRC approach that the WAP complex is decreasing its potential capacity to conserve species richness. This process is mainly due to the rapid and extended agricultural expansion taking place around the complex. A better understanding of the ecological dynamics occurring in the peripheral regions of reserves and the consideration of development needs are key variables to achieve conservation goals in protected areas. 相似文献
73.
Sequencing-based typing of MICA reveals 33 alleles: a study on linkage with classical HLA genes 总被引:1,自引:0,他引:1
74.
Tessier C Quinn P Koumanov K Trugnan G Rainteau D Wolf C 《European biophysics journal : EBJ》2004,33(6):513-521
The phase behaviour of mixed molecular species of phosphatidylethanolamine, phosphatidylserine and sphingomyelin of biological origin were examined in aqueous co-dispersions using synchrotron X-ray diffraction. The co-dispersions of phospholipids studied were aimed to model the mixing of lipids populating the cytoplasmic and outer leaflets in the resting or scrambled activated cell membrane. Mixtures enriched with phosphatidylethanolamine and phosphatidylserine were characterized by a phase separation of non-lamellar phases (cubic and inverted hexagonal) with a lamellar gel phase comprising the most saturated molecular species. Inclusion of sphingomyelin in the mixture resulted in a suppression of the hexagonal-II phase in favour of lamellar phases at temperatures where a proportion of the phospholipid was fluid. The effect was also dependent on the total amount of sphingomyelin in ternary mixtures, and the lamellar phase dominated in mixtures containing more than 30 mol%, irrespective of the relative proportions of phosphatidylserine/sphingomyelin. A transition from gel to liquid-crystal phase was detected by wide-angle scattering during heating scans of ternary mixtures enriched in sphingomyelin and was shown by thermal cycling experiments to be coupled with a hexagonal-II phase to lamellar transition. In such samples there was evidence of a coexistence of non-lamellar phases with a lamellar gel phase. A transition of the gel phase to the fluid state on heating from 35 to 41 °C was evidenced by a progressive increase in the lamellar d-spacing. The presence of calcium enhanced the phase separation of a lamellar gel phase from a hexagonal-II phase in mixtures enriched in phosphatidylserine. This effect was counteracted by charge screening with 150 mM NaCl. The effect of sphingomyelin on stabilizing the lamellar phase is discussed in the context of an altered composition in the cytoplasmic/outer leaflets of the plasma membrane resulting from scrambling of the phospholipid distribution. The results suggest that a lamellar structure can be retained by the inward translocation of sphingomyelin in biological membranes. The presence of monovalent cations serves also to stabilize the bilayer in activated cells where a translocation of aminoglycerophospholipids and an influx of calcium occur simultaneously.Abbreviations PC phosphatidylcholine - PE phosphatidylethanolamine - PS phosphatidylserine - SAXS small-angle X-ray scattering - SM sphingomyelin - WAXS wide-angle X-ray scattering - XRD X-ray diffraction 相似文献
75.
Le Hir M Hegyi I Cueni-Loffing D Loffing J Kaissling B 《Histochemistry and cell biology》2005,123(4-5):335-346
Fibrosis is considered as a central factor in the loss of renal function in chronic kidney diseases. The origin of fibroblasts and myofibroblasts that accumulate in the interstitium of the diseased kidney is still a matter of debate. It has been shown that accumulation of myofibroblasts in inflamed and fibrotic kidneys is associated with upregulation of fibroblast-specific protein 1 (FSP1, S100A4), not only in the renal interstitium but also in the injured renal epithelia. The tubular expression of FSP1 has been taken as evidence of myofibroblast formation by epithelial–mesenchymal transition (EMT). The identity of FSP1/S100A4 cells has not been defined in detail. We originally intended to use FSP1/S100A4 as a marker of putative EMT in a model of distal tubular injury. However, since the immunoreactivity of FSP1 did not seem to fit with the distribution and shape of fibroblasts or myofibroblasts, we undertook the characterization of FSP1/S100A4-expressing cells in the interstitium of rodent kidneys. We performed immunolabeling for FSP1/S100A4 on thin cryostat sections of perfusion-fixed rat and mouse kidneys with peritubular inflammation, induced by thiazides and glomerulonephritis, respectively, in combination with ecto-5-nucleotidase (5NT), recognizing local cortical peritubular fibroblasts, with CD45, MHC class II, CD3, CD4 and Thy 1, recognizing mononuclear cells, with alpha smooth muscle actin (SMA), as marker for myofibroblasts, and vimentin for intracellular intermediate filaments in cells of mesenchymal origin. In the healthy interstitium of rodents the rare FSP1/S100A4+ cells consistently co-expressed CD45 or lymphocyte surface molecules. Around the injured distal tubules of rats treated for 3–4 days with thiazides, FSP1+/S100A4+, 5NT+, SMA+, CD45+ and MHC class II+ cells accumulated. FSP1+/S100A4+ cells consistently co-expressed CD45. In the inflamed regions, SMA was co-expressed by 5NT+ cells. In glomerulonephritic mice, FSP1+/S100A4+ cells co-expressed Thy 1, CD4 or CD3. Thus, in the inflamed interstitium around distal tubules of rats and of glomerulonephritic mice, the majority of FSP1+ cells express markers of mononuclear cells. Consequently, the usefulness of FSP1/S100A4 as a tool for detection of (myo)fibroblasts in inflamed kidneys and of EMT in vivo is put into question. In the given rat model the consistent co-expression of SMA and 5NT suggests that myofibroblasts originate from resident peritubular fibroblasts.Ivan Hegyi and Michel Le Hir contributed equally to the study 相似文献
76.
Guivarc'h A Rembur J Goetz M Roitsch T Noin M Schmülling T Chriqui D 《Journal of experimental botany》2002,53(369):621-629
The developmental characteristics of a transgenic tobacco line (BIK62) expressing the ipt cytokinin-biosynthetic gene under the control of a tagged promoter were analysed. In situ hybridization and cytokinin immunocytochemistry revealed that the ipt gene was mainly expressed in the axillary buds after the floral transition. The ipt-expressing axillary buds presented morphological alterations such as short and narrow scale-leaflets, and swollen internodes filled with starch grains, giving rise to short and tuberized lateral branches. In addition, the modification of the endogenous cytokinin balance in the axillary meristems resulted in a fast rate of leaf initiation and cytokinins accumulated mostly in the lateral zones of the reactivated axillary meristems, suggesting a role in leaf organogenesis. Cell cycle analysis revealed that the reactivated axillary meristems were characterized by predominant S+G2 nuclei. Terminal internodes displayed low levels of hexose and sucrose concomitant with starch accumulation. Extracellular invertases (EC 3.1.26) were also present in higher amounts in the tuberizing internodes compared to the axillary buds of wild-type tobacco. These results underline the role of cytokinins in cell cycle regulation and in the creation of a sink--source effect. They also provide new information about cytokinin involvement in the process of tuberization and their overproduction in axillary buds giving rise to tuberized lateral branches in a naturally non-tuberizing species. 相似文献
77.
Proteomics: a link between genomics,genetics and physiology 总被引:16,自引:0,他引:16
Thanks to spectacular advances in the techniques for identifying proteins separated by two-dimensional electrophoresis and in methods for large-scale analysis of proteome variations, proteomics is becoming an essential methodology in various fields of plant biology. In the study of pleiotropic effects of mutants and in the analysis of responses to hormones and to environmental changes, the identification of involved metabolic pathways can be deduced from the function of affected proteins. In molecular quantitative genetics, proteomics can be used to map translated genes and loci controlling their expression, which can be used to identify proteins accounting for the variation of complex phenotypic traits. Linking gene expression to cell metabolism on the one hand and to genetic maps on the other, proteomics is a central tool for functional genomics. 相似文献
78.
Zeisel MB Druet VA Sibilia J Klein JP Quesniaux V Wachsmann D 《Journal of immunology (Baltimore, Md. : 1950)》2005,174(11):7393-7397
Focal adhesion kinase (FAK) is a nonreceptor protein tyrosine kinase involved in signaling downstream of integrins, linking bacterial detection, cell entry, and initiation of proinflammatory response through MAPKs and NF-kappaB activation. In this study, using protein I/II from Streptococcus mutans as a model activator of FAK, we investigated the potential link between FAK and TLR pathways. Using macrophages from TLR- or MyD88-deficient mice, we report that MyD88 plays a major role in FAK-dependent protein I/II-induced cytokine release. However, response to protein I/II stimulation was independent of TLR4, TLR2, and TLR6. The data suggest that there is a cross talk between FAK and MyD88 signaling pathways. Moreover, MyD88-dependent, LPS-induced IL-6 secretion by human and murine fibroblasts required the presence of FAK, confirming that MyD88 and FAK pathways are interlinked. 相似文献
79.
Incentivising fire management in Pindan (Acacia shrubland): A proposed fuel type for Australia's Savanna burning greenhouse gas emissions abatement methodology 下载免费PDF全文
Dominique Lynch Jeremy Russell‐Smith Andrew C. Edwards Jay Evans Cameron Yates 《Ecological Management & Restoration》2018,19(3):230-238
The Australian Government has sanctioned development of greenhouse gas emissions (GHG) abatement methodologies to meet international emissions reduction obligations. Savanna burning emissions abatement methodologies have been available since 2012, and there are currently 72 registered projects covering approximately 32 million ha. Abatement to date has exceeded 4 million tonnes of carbon dioxide equivalent (CO2‐e) principally through the application of low intensity early dry season fire management to reduce the amount of biomass combusted in higher intensity late dry season (LDS) fires. Savanna burning projects can only be conducted on areas with eligible fire‐prone vegetation fuel types where implementing the improved fire management regime is considered ecologically appropriate. This study assesses the suitability of including tall Acacia shrublands (‘Pindan’) as a new eligible fuel type. These shrublands make up 12% (~2 million ha) of the Kimberley region, Western Australia, where, on average, 32% is fire affected annually, mostly in the LDS. A standard assessment protocol was applied to describe vegetation fuel type structural and pyrolysis characteristics. We show that Pindan (i) can be identified and mapped as a unique tall Acacia shrubland vegetation fuel type, (ii) characterised by a significantly greater shrubby fuel load biomass, and (iii) the conservation status of which would benefit from imposition of strategic prescribed burning programme. Savanna burning projects in the Pindan fuel type could potentially abate up to 24.43 t.CO2‐e/km2 per year, generating significant income and employment opportunities for predominantly Indigenous land managers in the region. 相似文献
80.
Langin D 《Cell metabolism》2011,14(5):569-570
Adipose tissue is the main site of storage and mobilization of lipid. In a recent study published in Nature, Arner et?al. (2011) report that high storage and low removal of adipose triglycerides promotes obesity, whereas low storage and low removal favor the development of dyslipidemia in humans. 相似文献