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31.
Laetitia Mathon Virginie Marques Stéphanie Manel Camille Albouy Marco Andrello Emilie Boulanger Julie Deter Régis Hocdé Fabien Leprieur Tom B. Letessier Nicolas Loiseau Eva Maire Alice Valentini Laurent Vigliola Florian Baletaud Sandra Bessudo Tony Dejean Nadia Faure Pierre-Edouard Guerin Meret Jucker Jean-Baptiste Juhel Kadarusman Andrea Polanco F. Laurent Pouyaud Dario Schwörer Kirsten F. Thompson Marc Troussellier Hagi Yulia Sugeha Laure Velez Xiaowei Zhang Wenjun Zhong Loïc Pellissier David Mouillot 《Global Ecology and Biogeography》2023,32(8):1336-1352
Aim
Coastal fishes have a fundamental role in marine ecosystem functioning and contributions to people, but face increasing threats due to climate change, habitat degradation and overexploitation. The extent to which human pressures are impacting coastal fish biodiversity in comparison with geographic and environmental factors at large spatial scale is still under scrutiny. Here, we took advantage of environmental DNA (eDNA) metabarcoding to investigate the relationship between fish biodiversity, including taxonomic and genetic components, and environmental but also socio-economic factors.Location
Tropical, temperate and polar coastal areas.Time period
Present day.Major taxa studied
Marine fishes.Methods
We analysed fish eDNA in 263 stations (samples) in 68 sites distributed across polar, temperate and tropical regions. We modelled the effect of environmental, geographic and socio-economic factors on α- and β-diversity. We then computed the partial effect of each factor on several fish biodiversity components using taxonomic molecular units (MOTU) and genetic sequences. We also investigated the relationship between fish genetic α- and β-diversity measured from our barcodes, and phylogenetic but also functional diversity.Results
We show that fish eDNA MOTU and sequence α- and β-diversity have the strongest correlation with environmental factors on coastal ecosystems worldwide. However, our models also reveal a negative correlation between biodiversity and human dependence on marine ecosystems. In areas with high dependence, diversity of all fish, cryptobenthic fish and large fish MOTUs declined steeply. Finally, we show that a sequence diversity index, accounting for genetic distance between pairs of MOTUs, within and between communities, is a reliable proxy of phylogenetic and functional diversity.Main conclusions
Together, our results demonstrate that short eDNA sequences can be used to assess climate and direct human impacts on marine biodiversity at large scale in the Anthropocene and can further be extended to investigate biodiversity in its phylogenetic and functional dimensions. 相似文献32.
Alice J. Szuna Roger W. Blain 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,620(2):211-216
Analysis of a new antibacterial agent, Ro 23-9424 (I), in plasma has been complicated by the fact that its metabolite, fleroxacin (II), is formed not only in vivo, but also nonenzymatically by the hydrolysis of the ester bond of I. In order to minimize sample preparation time and possible hydrolysis during sample preparation, a high-performance liquid chromatographic procedure was developed which features direct injection of plasma and multidimensional chromatography. The first dimension size-exclusion separation allows plasma proteins to elute with the column void volume. The second dimension reversed-phase column provides a high-resolution separation dependent upon the hydrophobicity of the sample species. With a 5-μl injection, the limit of quantitation of the method is 0.35 μg/ml for I and 0.27 μg/ml for II. The method was used to determine steady state plasma vs. time profiles for I and II from 750 mg i.v. doses of I administered twice daily. 相似文献
33.
Summary A buffer system consisting of 50 mM Tris-HCl-TRIZMA base plus 10 mM EDTA was used to rapidly dissolve gellan gels used for maintaining transformed carrot root cultures. The optimum conditions of pH 7.5 in the presence of 10 mM EDTA for dissolving gellan were first worked out on a model test system containing 0.4% gellan, 0.025% MgSO4·7H2O, and blue dye. The conditions were then tested on gellan gels (0.2% gellan plus nutrients) containing carrot roots. This gel dissolution system was rapid (18 to 20 min), did not require heating, and could also be efficiently performed at 4 °C. Furthermore, the buffer system used for gel dissolution is a standard one used for plant cell fractionation studies. 相似文献
34.
35.
Søren Bak Rachel Alice Kahn Carl Erik Olsen Barbara Ann Halkier 《The Plant journal : for cell and molecular biology》1997,11(2):191-201
Obtusifoliol 14β-demethylase from Sorghum bicolor (L.) Moench has been cloned using a gene-specific probe generated using PCR primers designed from an internal 14 amino acid sequence. The sequence identifies sorghum obtusifoliol 14α-demethylase as a cytochrome P450 and it is assigned to the CYP51 family together with the sterol 14α-demethylases from fungi and mammals. The presence of highly conserved regions in the amino acid sequences, analogous substrates and the same metabolic role demonstrate that the sterol 14α-demethylases are orthologous enzymes. The sterol 14α-demethylases catalyse an essential step in sterol biosynthesis as evidenced by the absence of a 14α-methyl group in all known functional sterols. A functional sorghum obtusifoliol 14α-demethylase was expressed at high levels in Escherichia coli and purified using an efficient method based on temperature-induced Triton X-114 phase partitioning. The recombinant purified enzyme produced a type I spectrum with obtusifoliol as substrate. Reconstitution of purified recombinant enzyme with sorghum NADPH—cytochrome P450 reductase in dilaurylphosphatidylcholine micelles confirms that obtusifoliol 14α-demethylase catalyses the 14α-demethylation of obtusifoliol to 4α-methyl-5α-ergosta-8,14,24(28)-trien-3β-ol as evidenced by GC—MS. The isolation of a cDNA clone encoding the plant sterol 14α-demethylase, combined with the previously isolated cDNA clones for fungal and mammalian sterol 14α-demethylases, provides an important tool in the rational design of specific inhibitors towards the individual sterol 14α-demethylases. 相似文献
36.
Alice Abd El-Aleem Ingolf Böhm Samia Temtamy Mostafa El-Awady Mohamed Awadalla Jörg Schmidtke Manfred Stuhrmann 《Human genetics》1995,96(5):577-584
Molecular genetic analysis of individuals from 6 Egyptian and 33 German families with fragile X syndrome and 240 further patients with mental retardation was performed applying a completely non-radioactive system. The aim of our study was the development of a non-radioactive detection method and its implementation in molecular diagnosis of the fragile X syndrome. Furthermore, we wanted to assess differences in the mutation sizes between Egyptian and German patients and between Egyptian and German carriers of a premutation. Using non-radioactive polymerase chain reaction (PCR), agarose gel electrophoresis and blotting of the PCR products, followed by hybridisation with a digoxigenin-labelled oligonucleotide probe (CGG)5 and chemiluminescent detection, we identified the fragile X full mutation (amplification of a CGG repeat in the FMR-1 gene ranging from several hundred to several thousand repeat units) in all patients. We observed no differences in the length of the CGG repeat between the Egyptian and German patients and carriers, respectively. However, in one prenatal diagnosis, we detected only one normal sized allele in a female fetus using the PCR-agarose assay, whereas Southern blot analysis with the digoxigenin labelled probe StB 12.3 revealed presence of a full mutation. Our newly established nonradioactive genomic blotting method is based on the conventional radioactive Southern blot analysis. Labelling of the probe StB 12.3 with digoxigenin via PCR allowed the detection of normal, premutated and fully mutated alleles. For exact sizing of small premutated or large normal alleles, we separated digoxigenin labelled PCR products through denaturing poly-acrylamide gelelectrophoresis (PAGE) and transfered them to a nylon membrane using a gel dryer. The blotted PCR-fragments can easily be detected with alkaline phosphate-labelled anti-digoxigenin antibody. The number of trinucleotide repeat units can be determined by scoring the detected bands against a digoxigenated M13 sequencing ladder. Our newly developed digoxigenin/chemiluminescence approach using PCR and Southern blot analysis provides reliable results for routine detection of full fragile X mutations and premutations. 相似文献
37.
Adherence through carbohydrate-binding adhesins is an earlystep in colonization of the lung by gram-negative organisms,and because published data indicate that binding involves mannosegroups, we tested the ability of a ß-linked acetylmannan(acemannan) to inhibit adherence of Pseudomonus aeruginosa tocultures of human lung epithelial cells. Adherence of radiolabelledP.aeruginosa to A549 cells (a type II-like pneurnocyte line)increased linearly with the duration of the incubation. Acemannaninhibited adherence of bacteria, and the extent of inhibitionwas related to the concentration of the mannan. Inhibition requiredcontinued contact between acemannan and the target epithelialcells; cells washed free of acemannan no longer discouragedbacterial binding. Comparison of binding between seven strainsof P.aeruginosa indicated that fewer mucoid than non-mucoidbacteria adhered, but binding of either phenotype was inhibitedby acemannan. Mannose methyl -D-mannopyranoside, methyl ß-D-mannopyrannosideand dextran did not affect adherence of any of the non-mucoidstrains. Mannose inhibited adherence by one mucoid strain, butnot the other, indicating differences between strains of thesame phenotype. Since prior treatment of epithelial cells withconcanavalin A did not affect acemannan-induced inhibition ofbacterial adherence, we concluded that the inhibitory effectof acemannan probably does not involve mannose-containing receptors. bacterial-host interactions lung epithelium mucoid strains non-mucoid strains 相似文献
38.
Alice H. Lin Patricia L. Ruppel Robert R. Gorman 《Prostaglandins & other lipid mediators》1984,28(6):837-849
[3H] Leukotriene B4 (LTB4) binds concentration dependency to intact human polymorophonuclear leukocytes (PMN's). The binding is saturable, reaches equilibrium in 10 min at 4°C, and is readily reversible. Mathematical modeling analysis reveals biphasic binding of [3H] LTB4 indicating two discrete populations of binding sites. The high affinity binding sites have a dissociation constant of 0.46 × 10−9M and Bmax of 1.96 × 104 sites per neutrophil; the low affinity binding sites have a dissociation constant of 541 × 10−9M and a Bmax of 45.6 × 104 sites per neutrophil. Competitive binding experiments with structural analogues of LTB4 demonstrate that the interaction between LTB4 and the binding site is stereospecific, and correlates with the relative biological activity of the analogs. At 25°C[3H] LTB4 is rapidly dissociated from the binding site and metabolized to 20-OH and 20-COOH-LTB4. Purification of neutrophils in the presence of 5-lipoxygenase inhibitors significantly increases specific [3H] LTB4 binding, suggesting that LTB4 is biosynthesized during the purification procedure. These data suggest that stereospecific binding and metabolism of LTB4 in neutrophils are tightly coupled processes. 相似文献
39.
Ade–H and ade–I are two auxotrophic mutants of Chinese hamster ovary (CHO-K1) cells which specifically require adenine as the purine source to grow. The enzymatic defects of these mutants were examined in cell-free extracts. It was found that ade–H did not have any detectable adenylosuccinate synthetase activity and ade–I was defective in the adenylosuccinate lyase enzyme. The relevance of adenine-requiring mutants to the study of the regulation of purine metabolism in mammalian cells is discussed.This work was supported by research grants from the National Institute of Aging (AG00029) and the National Foundation, March of Dimes (1-423), and by a contract from the Center for Toxicological Research, Food and Drug Administration (72-213). David Patterson is a recipient of a Research Career Development Award from the National Institute of Arthritis, Metabolic and Digestive Diseases (AM00044).Contribution (No. 218) from the Eleanor Roosevelt Institute for Cancer Research. 相似文献
40.
Postreplication repair in Neurospora crassa 总被引:1,自引:0,他引:1
Summary Changes in the molecular weight of nascent DNA made after ultraviolet (UV) irradiation have been studied in the excision-defective Neurospora mutant uvs-2 using isotopic pulse labeling, alkaline gradient centrifugation and alkaline filter elution. Both the size of nascent DNA and the rate of incorporation of label into DNA was reduced by UV light in a dose dependent manner. However, this DNA repair mutant did recover the ability to synthesize control-like high molecular weight DNA 3 hours after UV treatment, although the rate of DNA synthesis remained depressed after the temporary block to elongation (or ligation) had been overcome. Photoreactivation partially eliminated the depression of DNA synthesis rate and UV light killing of cells, providing strong evidence that the effects on DNA synthesis and killing were caused by pyrimidine cyclobutane dimers. The caffeine inhibition repair studies performed were difficult to quantitate but did suggest either partial inhibition of a single repair pathway or alternate postreplication DNA repair pathways in Neurospora. No enhancement in killing was detected after UV irradiation when cells were grown on caffeine containing plates. 相似文献