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51.
In the immature rat uterus, high concentrations of androgens competed specifically with estradiol on the estrogen receptor (RE). This competition was stereospecific for C19 steroids bearing a 17β and/or 3 hydroxyl group. Very low affinity ligands, such as testosterone, could not compete with estradiol at equilibrium but decreased the association rate of estradiol on its receptor. High doses (> 0.4mg) of 5 α aihydrotestosterone provoked as the nuclear translocation of RE. The nuclear receptor thus formed displayed the same 5.2 S sedimentation constant as that induced by estradiol. We conclude that the weak affinity binding of androgens to the estrogen receptor is sufficient to induce its nuclear translocation provided androgen concentration is high enough in uterus to occupy the estradiol binding site. Conversely, progesterone which does not bind RE could not provoke its nuclear translocation. 相似文献
52.
An important new collection of otoliths from theCalcaire Grossier of the Paris Basin, as well as a critical review of already published material is studied and reveals the presence of 56 species. Five of these are new: Muraenesox spatulus, Genus Synodontidarum intermedius, Genus Ophidiidarum spinosus, Chanda bohlkei and Mene sekharani. The assemblage is indicative of tropical to subtropical marine and neritic environment with solid bottom. Biogeographically, it shows affinities with the recent Indo-pacific fauna. The association of the sites at Fercourt and Château-Rouge is clearly different from the one found at the sites of Condé-en-Brie and Damery, as it is less littoral than the second association mentioned. 相似文献
53.
Claude-Michel Gaillardin Geneviève Sylvestre Henri Heslot 《Archives of microbiology》1975,104(1):89-94
Unstable clones excreting L-lysine into their growth medium are obtained at a very high frequency following UV irradiation in both haploid and diploid strains of Saccharomycopsis lipolytica, provided they carry a mutation affecting the first enzyme of the lysine pathway and confering resistance to end product inhibition. The phenotype can be stabilized in some sublines; it appears as dominant and coupled with a decrease in spore viability. Excretion in batch cultures is confined to the end of the exponential phase, and seems not to consist in a simple release of the lysine pool content. 相似文献
54.
Pollen dispersal in sugar beet production fields 总被引:1,自引:0,他引:1
Henri Darmency Etienne K. Klein Thierry Gestat De Garanbé Pierre-Henri Gouyon Marc Richard-Molard Claude Muchembled 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(6):1083-1092
Pollen-mediated gene flow has important implications for biodiversity conservation and for breeders and farmers’ activities.
In sugar beet production fields, a few sugar beet bolters can produce pollen as well as be fertilized by wild and weed beet.
Since the crop, the wild beets, and the weed beets are the same species and intercross freely, the question of pollen flow
is an important issue to determine the potential dispersal of transgenes from field to field and to wild habitats. We report
here an experiment to describe pollen dispersal from a small herbicide-resistant sugar beet source towards male sterile target
plants located along radiating lines up to 1,200 m away. Individual dispersal functions were inferred from statistical analyses
and compared. Pollen limitation, as expected in root-production fields, was confirmed at all the distances from the pollen
source. The number of resistant seeds produced by bait plants best fitted a fat-tailed probability distribution curve of pollen
grains (power–law) dependent on the distance from the pollen source. A literature survey confirmed that power–law function
could fit in most cases. The b coefficient was lower than 2. The number of fertilized flowers by background (herbicide-susceptible) pollen grains was uniform
across the whole field. Airborne pollen had a fertilization impact equivalent to that of one adjacent bolter. The individual
dispersal function from different pollen sources can be integrated to provide the pollen cloud composition for a given target
plant, thus allowing modeling of gene flow in a field, inter-fields in a small region, and also in seed-production area. Long-distance
pollen flow is not negligible and could play an important role in rapid transgene dispersal from crop to wild and weed beets
in the landscape. The removing of any bolting, herbicide-resistant sugar beet should be compulsory to prevent the occurrence
of herbicide-resistant weed beet, thus preventing gene flow to wild populations and preserving the sustainable utility of
the resistant varieties. Whether such a goal is attainable remains an open question and certainly would be worth a large scale
experimental study. 相似文献
55.
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57.
Cristina Martini Sâmia Maria Tauk-Tornisielo Carolina Brito Codato Reinaldo Gaspar Bastos Sandra Regina Ceccato-Antonini 《World journal of microbiology & biotechnology》2016,32(5):80
The search for new microbial strains that are able to withstand inhibitors released from hemicellulosic hydrolysis and are also still able to convert sugars in ethanol/xylitol is highly desirable. A yeast strain isolated from sugarcane juice and identified as Meyerozyma guilliermondii was evaluated for the ability to grow and ferment pentoses in synthetic media and in sugarcane bagasse hydrolysate. The yeast grew in xylose, arabinose and glucose at the same rate at an initial medium pH of 5.5. At pH 4.5, the yeast grew more slowly in arabinose. There was no sugar exhaustion within 60 h. At higher xylose concentrations with a higher initial cell concentration, sugar was exhausted within 96 h at pH 4.5. An increase of 350 % in biomass was obtained in detoxified hydrolysates, whereas supplementation with 3 g/L yeast extract increased biomass production by approximately 40 %. Ethanol and xylitol were produced more significantly in supplemented hydrolysates regardless of detoxification. Xylose consumption was enhanced in supplemented hydrolysates and arabinose was consumed only when xylose and glucose were no longer available. Supplementation had a greater impact on ethanol yield and productivity than detoxification; however, the product yields obtained in the present study are still much lower when compared to other yeast species in bagasse hydrolysate. By the other hand, the fermentation of both xylose and arabinose and capability of withstanding inhibitors are important characteristics of the strain assayed. 相似文献
58.
Cecile Bessou Claudine Basset-Mens Cynthia Latunussa Alice Vélu Hadrien Heitz Henri Vannière Jean-Pierre Caliman 《The International Journal of Life Cycle Assessment》2016,21(3):297-310
Purpose
As highlighted in recent reviews, there is a need to harmonise the way life cycle assessment (LCA) of perennial crops is conducted. In most published LCA on perennial crops, the modelling of the agricultural production is based on data sets for just one productive year. This may be misleading since performance and impacts of the system may greatly vary year by year. The purposes of this study are to analyse how partial modelling of the perennial cycle through non-holistic data collection may affect LCA results and to make recommendations.Methods
Three modelling choices for the perennial crop cycle were tested in parallel in two contrasted LCA case studies: oil palm fruits from Indonesia, and small citrus from Morocco. Modelling choices tested were as follows: (i) a chronological modelling over the complete crop cycle of orchards, (ii) a 3-year average from the productive phase, and (iii) various single years from the productive phase. In both case studies, the system boundary was a cradle-to-farm gate with a functional unit of 1 kg fresh fruits. LCA midpoint impacts were calculated with ReCiPe 2008 in Simapro©V.7. We first analysed how inputs, yields and potential impacts varied over time. We then analysed process contributions in the baseline model, i.e. the chronological modelling, and finally compared LCA results for the various perennial modelling choices.Results and discussion
Agricultural practices, yields and impacts varied over the years especially during the first 3–9 years depending on the case study. In both case studies, the modelling choices to account or not for the whole perennial cycle drastically influenced LCA results. The differences could be explained by the inclusion or not of the yearly variability and the accounting or not of the immature phase, which contributed to 7–40 or 6.5–29 % of all impact categories for oil palm fruit and citrus, respectively.Conclusions
The chosen approach to model the perennial cycle influenced the final LCA results for two contrasted case studies and deserved specific attention. Although data availability may remain the limiting factor in most cases, assumptions can be made to interpolate or extrapolate some data sets or to consolidate data sets from chronosequences (i.e. modular modelling). In all cases, we suggest that the approach chosen to model the perennial cycle and the representativeness of associated collected data should be made transparent and discussed. Further research work is needed to improve the understanding and modelling of perennial crop functioning and LCA assessment.59.
Ben Ali Y Chahinian H Petry S Muller G Lebrun R Verger R Carrière F Mandrich L Rossi M Manco G Sarda L Abousalham A 《Biochemistry》2006,45(47):14183-14191
Hormone-sensitive lipase (HSL) contributes importantly to the mobilization of fatty acids from the triacylglycerols stored in adipocytes, which provide the main source of energy in mammals. On the basis of amino acid sequence alignments and three-dimensional structures, this enzyme was previously found to be a suitable template for defining a family of serine carboxylester hydrolases. In this study, the HSL family members are characterized rather on the basis of their inhibition by 5-methoxy-3-(4-phenoxyphenyl)-3H-[1,3,4]oxadiazol-2-one (compound 7600). This compound inhibits mammalian HSL as well as other HSL family members, such as EST2 from the thermophilic eubacterium Alicyclobacillus acidocaldarius and AFEST from the hyperthermophilic archaeon Archaeoglobus fulgidus. Various carboxylester hydrolases that are not members of the HSL family were found not to be inhibited by compound 7600 under the same experimental conditions. These include nonlipolytic hydrolases such as Torpedo californica acetylcholinesterase and pig liver esterase, as well as lipolytic hydrolases such as human pancreatic lipase, dog gastric lipase, Thermomyces lanuginosus lipase, and Bacillus subtilis LipA. When vinyl esters were used as substrates, the residual activity of HSL, AFEST, and EST2 decreased with an increase in compound 7600 concentration in the incubation mixture. The inhibitor concentration at which the enzyme activity decreased to 50% after incubation for 5 min was 70, 20, and 15 nM with HSL, AFEST, and EST2, respectively. Treating EST2 and AFEST with the inhibitor resulted in an increase in the molecular mass, as established by performing matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis. This increase in the molecular mass, which corresponds approximately to the molecular mass of the inhibitor, indicates that a covalent enzyme-inhibitor complex has been formed. Surface-enhanced laser desorption ionization time-of-flight mass spectrometry analysis of a trypsin digest of AFEST treated with the inhibitor or not treated showed the occurrence of an increase in the molecular masses of the "GESAGG"-containing peptide, which is compatible with the formation of a covalent complex with the inhibitor. 相似文献
60.
Insects are not only major vectors of mammalian viruses, but are also host to insect-restricted viruses that can potentially be transmitted to mammals. While mammalian innate immune responses to arboviruses are well studied, less is known about how mammalian cells respond to viruses that are restricted to infect only invertebrates. Here we demonstrate that IIV-6, a DNA virus of the family Iridoviridae, is able to induce a type I interferon-dependent antiviral immune response in mammalian cells. Although IIV-6 is a DNA virus, we demonstrate that the immune response activated during IIV-6 infection is mediated by the RIG-I-like receptor (RLR) pathway, and not the canonical DNA sensing pathway via cGAS/STING. We further show that RNA polymerase III is required for maximal IFN-β secretion, suggesting that viral DNA is transcribed by this enzyme into an RNA species capable of activating the RLR pathway. Finally, we demonstrate that the RLR-driven mammalian innate immune response to IIV-6 is functionally capable of protecting cells from subsequent infection with the arboviruses Vesicular Stomatitis virus and Kunjin virus. These results represent a novel example of an invertebrate DNA virus activating a canonically RNA sensing pathway in the mammalian innate immune response, which reduces viral load of ensuing arboviral infection. 相似文献