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991.
Fabrice Compain Nawel Aït-Ammar Françoise Botterel Laure Gibault Francoise Le Pimpec Barthes Eric Dannaoui 《Mycopathologia》2017,182(9-10):907-913
We report here a case of cavitary pneumonia due to Rhizopus homothallicus in a diabetic patient. This is the first proven case of R. homothallicus infection in Western countries and the third case described worldwide. The organism was isolated from lung biopsy and identified after amplification and sequencing of the internal transcribed spacer region. 相似文献
992.
Forest plant community as a driver of soil biodiversity: experimental evidence from collembolan assemblages through large‐scale and long‐term removal of oak canopy trees Quercus petraea
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Ludovic Henneron Michaël Aubert Fréderic Archaux Fabrice Bureau Yann Dumas François Ningre Claudine Richter Philippe Balandier Matthieu Chauvat 《Oikos》2017,126(3):420-434
Plant–soil interactions are increasingly recognized to play a major role in terrestrial ecosystems functioning. However, few studies to date have focused on slow dynamic ecosystems such as forests. As they are vertically stratified by multiple vegetation strata, canopy tree removal by thinning operations could alter forest plant community through tree canopy opening. Very little is known about cascading effects on soil biodiversity. We conducted a large‐scale, multi‐site assessment of collembolan assemblage response to long‐term canopy tree removal in sessile oak Quercus petraea temperate forests. A total of 33 experimental plots were studied covering a large gradient of canopy tree basal area, stand age and local abiotic contexts. Collembolan abundance strongly declined with canopy tree removal in early forest successional stage and this was mediated by negative effect of understory plant community composition changes, i.e. shift from moss and forb to tree seedling, fern, shrub and grass species. Negative effect of this composition shift on collembolan species richness was largely offset by positive effect of the increase in understory plant species richness. This gives support to both the plant mass‐ratio and functional diversity hypotheses. Collembolan functional groups had contrasting response patterns, which were mediated by different ecological factors. Epedaphic (r‐strategist) abundance and species richness increased with canopy tree removal in relation with the increase in understory plant species richness. In contrast, euedaphic (K‐strategist) abundance and species richness declined with canopy tree removal in early forest successional stage in relation with changes in understory plant community composition and species richness, as well as microclimatic conditions. Overall, our study provides experimental evidence that forest plant community can be a strong driver of collembolan assemblages. It also emphasizes the role of trees as foundation species of forest ecosystems that can shape soil biodiversity through their regulation of understory plant community and ecosystem abiotic conditions. 相似文献
993.
There is increasing awareness that many terrestrial and aquatic organisms are not strictly heterotrophic or autotrophic but rather mixotrophic. Mixotrophy is an intermediate nutritional strategy, merging autotrophy and heterotrophy to acquire organic carbon and/or other elements, mainly N, P or Fe. We show that both terrestrial and aquatic mixotrophs fall into three categories, namely necrotrophic (where autotrophs prey on other organisms), biotrophic (where heterotrophs gain autotrophy by symbiosis) and absorbotrophic (where autotrophs take up environmental organic molecules). Here we discuss their physiological and ecological relevance since mixotrophy is found in virtually every ecosystem and occurs across the whole eukaryotic phylogeny, suggesting an evolutionary pressure towards mixotrophy. Ecosystem dynamics tend to separate light from non‐carbon nutrients (N and P resources): the biological pump and water stratification in aquatic ecosystems deplete non‐carbon nutrients from the photic zone, while terrestrial plant successions create a canopy layer with light but devoid of non‐carbon soil nutrients. In both aquatic and terrestrial environments organisms face a grand écart (dancer's splits, i.e., the need to reconcile two opposing needs) between optimal conditions for photosynthesis vs. gain of non‐carbon elements. We suggest that mixotrophy allows adaptation of organisms to such ubiquist environmental gradients, ultimately explaining why mixotrophic strategies are widespread. 相似文献
994.
Expression patterns of sterol transporters NPC1 and NPC2 in the cnidarian–dinoflagellate symbiosis
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Vincent Dani Fabrice Priouzeau Marjolijn Mertz Magali Mondin Sophie Pagnotta Sandra Lacas‐Gervais Simon K. Davy Cécile Sabourault 《Cellular microbiology》2017,19(10)
The symbiotic interaction between cnidarians (e.g., corals and sea anemones) and photosynthetic dinoflagellates of the genus Symbiodinium is triggered by both host–symbiont recognition processes and metabolic exchange between the 2 partners. The molecular communication is crucial for homeostatic regulation of the symbiosis, both under normal conditions and during stresses that further lead to symbiosis collapse. It is therefore important to identify and fully characterise the key players of this intimate interaction at the symbiotic interface. In this study, we determined the cellular and subcellular localization and expression of the sterol‐trafficking Niemann–Pick type C proteins (NPC1 and NPC2) in the symbiotic sea anemones Anemonia viridis and Aiptasia sp. We first established that NPC1 is localised within vesicles in host tissues and to the symbiosome membranes in several anthozoan species. We demonstrated that the canonical NPC2‐a protein is mainly expressed in the epidermis, whereas the NPC2‐d protein is closely associated with symbiosome membranes. Furthermore, we showed that the expression of the NPC2‐d protein is correlated with symbiont presence in healthy symbiotic specimens. As npc2‐d is a cnidarian‐specific duplicated gene, we hypothesised that it probably arose from a subfunctionalisation process that might result in a gain of function and symbiosis adaptation in anthozoans. Niemann–Pick type C proteins may be key players in a functional symbiosis and be useful tools to study host–symbiont interactions in the anthozoan–dinoflagellate association. 相似文献
995.
Ulrich Brose Julia L. Blanchard Anna Eklöf Nuria Galiana Martin Hartvig Myriam R. Hirt Gregor Kalinkat Marie C. Nordström Eoin J. O'Gorman Björn C. Rall Florian D. Schneider Elisa Thébault Ute Jacob 《Biological reviews of the Cambridge Philosophical Society》2017,92(2):684-697
Understanding the consequences of species loss in complex ecological communities is one of the great challenges in current biodiversity research. For a long time, this topic has been addressed by traditional biodiversity experiments. Most of these approaches treat species as trait‐free, taxonomic units characterizing communities only by species number without accounting for species traits. However, extinctions do not occur at random as there is a clear correlation between extinction risk and species traits. In this review, we assume that large species will be most threatened by extinction and use novel allometric and size‐spectrum concepts that include body mass as a primary species trait at the levels of populations and individuals, respectively, to re‐assess three classic debates on the relationships between biodiversity and (i) food‐web structural complexity, (ii) community dynamic stability, and (iii) ecosystem functioning. Contrasting current expectations, size‐structured approaches suggest that the loss of large species, that typically exploit most resource species, may lead to future food webs that are less interwoven and more structured by chains of interactions and compartments. The disruption of natural body‐mass distributions maintaining food‐web stability may trigger avalanches of secondary extinctions and strong trophic cascades with expected knock‐on effects on the functionality of the ecosystems. Therefore, we argue that it is crucial to take into account body size as a species trait when analysing the consequences of biodiversity loss for natural ecosystems. Applying size‐structured approaches provides an integrative ecological concept that enables a better understanding of each species' unique role across communities and the causes and consequences of biodiversity loss. 相似文献
996.
Endogenous nandrolone metabolites in human urine: preliminary results to discriminate between endogenous and exogenous origin. 总被引:2,自引:0,他引:2
Bruno Le Bizec Fabrice Bryand Isabelle Gaudin Fabrice Monteau Frédéric Poulain Fran?ois Andre 《Steroids》2002,67(2):105-110
When administered to human subjects, nandrolone is metabolized into two main products, 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE). Recent studies demonstrated the endogenous production of these compounds in man at concentrations very close to the threshold of the International Olympic Committee (IOC), i.e. 2 ng/ml. Because the possibility of reaching or exceeding this fateful limit is difficult to exclude, a complementary biochemical parameter is necessary for the differentiation of endogenous 19-NA and 19-NE production from residues resulting from nandrolone consumption. We measured the endogenous concentrations of 19-NA and 19-NE in 385 urine samples from professional football players, and we studied the phase II metabolite composition in individuals excreting the highest concentrations. The results showed that around 30% of endogenous 19-norandrosterone was sulfo-conjugated, whereas 100% of 19-norandrosterone was excreted conjugated to a glucuronic acid when nandrolone was administered. This significant qualitative difference appears to be a promising complementary criterion to more definitively conclude about an athlete's culpability, especially when nandrolone metabolites are found in the low ng/ml range. 相似文献
997.
Genew, the Human Gene Nomenclature Database, is the only resource that provides data for all human genes which have approved symbols. It is managed by the HUGO Gene Nomenclature Committee (HGNC) as a confidential database, containing over 16 000 records, 80% of which are represented on the Web by searchable text files. The data in Genew are highly curated by HGNC editors and gene records can be searched on the Web by symbol or name to directly retrieve information on gene symbol, gene name, cytogenetic location, OMIM number and PubMed ID. Data are integrated with other human gene databases, e.g. GDB, LocusLink and SWISS-PROT, and approved gene symbols are carefully co-ordinated with the Mouse Genome Database (MGD). Approved gene symbols are available for querying and browsing at http://www.gene.ucl.ac.uk/cgi-bin/nomenclature/searchgenes.pl. 相似文献
998.
Uli Hacksell Norman Nash Ethan S. Burstein Fabrice Piu Glenn Croston Mark R. Brann 《Cytotechnology》2002,38(1-3):3-10
Chemical genomics is a new research paradigm with importantapplications in drug discovery. It links genomic targets withsmall-molecule chemistries thereby allowing for efficient targetvalidation and lead compound identification. ACADIA'schemical-genomics platform consists of a large and diverse small-moleculelibrary (800,000), a reference drug library (2,000), druggablegenomic targets (>300) and a cell-based functional assaytechnology (R-SATTM; Receptor Selection and AmplificationTechnology) that allows for ultra-high throughput screening(>500,000 data points/week) as well as high throughputpharmacology and profiling over a wide range of targets. Twoexamples are presented that illustrate the success of ourchemical-genomics approach: (i) The validation of inverse agonismat serotonin 5-HT2A receptors as an antipsychotic mechanismand the subsequent discovery of potent and selectively acting 5-HT2A inverse agonists, currently in preclinical development,and (ii) the discovery of the first ectopically binding subtype-selective muscarinic m1 agonist. 相似文献
999.
Karine Berthoin Fabrice Broeckaert Marjorie Robin Vincent Haufroid Claire De Burbure Alfred Bernard 《Biomarkers》2004,9(4):341-352
Very few biomarkers are available for the non-invasive detection of effects of urban air pollution on the respiratory tract. The objective was to evaluate whether Clara cell protein (CC16) and surfactant-associated protein-A (SP-A), two pulmonary secretory proteins, were useful in the detection of effects of urban air pollutants on the pulmonary epithelium. These proteins were determined in the serum of 53 policemen working in Brussels, Belgium, and a control group of 59 foresters working in the countryside. Except for ozone (O3), annual concentrations of the main air pollutants (PM10, NO2, CO, SO2 and benzene) were significantly higher in Brussels than in the country. The proportion of smokers was lower in urban policemen compared with foresters, but they smoked on average a similar number of cigarettes per day as confirmed by their urinary excretion of cotinine. Muconic acid, a marker of benzene exposure, was significantly higher in urban policemen than in foresters, in both smokers and non-smokers. Multiple regression analysis showed that the type of work, smoking habits and time spent outdoors and in a car were significant determinants of benzene uptake. Tobacco smoking impaired lung function to a similar extent in urban policemen and foresters. The serum levels of SP-A were significantly increased in smokers but were not different between policemen and foresters. Serum CC16 was significantly reduced by tobacco smoking and slightly decreased in policemen compared with foresters. Interestingly, the reduction of serum CC16 was more pronounced in the subgroup of traffic compared with survey policemen, the latter being also less exposed to benzene. The results suggest that serum pneumoproteins and especially serum CC16 could be useful in the detection of chronic effects of urban air pollutants on the respiratory epithelium of populations particularly at risk. 相似文献
1000.
Frank L. Greenway Lilian de Jonge Damian Blanchard Madlyn Frisard Steven R. Smith 《Obesity (Silver Spring, Md.)》2004,12(7):1152-1157
Objective: To evaluate the effect of a dietary supplement containing herbal caffeine (70 mg/dose) and ephedra (24 mg/dose; C&E) on metabolic rate, weight loss, body composition, and safety parameters. Research Methods and Procedures: In phase I, 12 healthy subjects with a BMI of 25 to 35 kg/m2 had resting metabolic rate (RMR) measured for 2 hours after ingesting C&E or a placebo on two occasions 1 week apart, followed by a 1‐week washout before phase II. In phase II, these 12 and 28 additional subjects were randomized to a 12‐week, double‐blind trial comparing C&E (3 times/day) to placebo. In phase III, the C&E group was given open‐label C&E for 3 months, and the placebo group was given C&E for 6 months. Results: In phase I, C&E gave an average 8 ± 0.1% (SE) rise in RMR over 2 hours compared with placebo (p < 0.01). In phase II, weight loss at 12 weeks was 3.5 ± 0.6 kg with C&E compared with 0.8 ± 0.5 kg with placebo (p < 0.02). The percentage fat lost, shown by DXA, was 7.9 ± 2.9% with C&E and 1.9 ± 1.1% with placebo (p < 0.05). Pulse decreased more in the placebo group that in the C&E group (p < 0.03). There were no differences in lipid levels or blood pressure. In phase III, there was a 6‐month loss of 7.3% and 7.8% of initial body weight for the groups on placebo and C&E during phase II, respectively. There were no serious adverse events. Discussion: C&E increased RMR significantly by 8% compared with placebo, promoted more weight and fat loss than placebo, and was well tolerated. 相似文献