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7-MethyljugIone, 8,8′-dihydroxy-4,4′-dimethoxy-6,6′-dimethyl-2,2′-binaphthyl-1,1′-quinone, 2-methylnaphthazarin, mamegakinone and euclein have been isolated from Euclea pseudebenus. Euclein is the 3,6′-dimer of 7-methyljuglone.  相似文献   
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Among the thermophilic fishes that have become established in the north-western Mediterranean as a consequence of sea warming, the yellowmouth barracuda (Sphyraena viridensis Cuvier, 1829) appears to be one of the most successful and abundant in the coastal rocky environment, having increasingly become the object of recreational and commercial exploitation in the study area. Lure-fishing sessions were carried out from May 2016 to November 2018 in the Catalan Sea (NE Spain) at dawn and dusk, with the aim of providing new insight into the behavioural, spatial and feeding ecology and vulnerability to angling of this poorly known species. Generalized mixed-effects linear models showed that S. viridensis is a crepuscular inshore dweller, whose vulnerability to angling is significantly influenced by solar and lunar light intensities, being highest in the pre-spawn and spawning periods. Asymmetries between dawn and dusk activity patterns were detected, evidently related to a drop in aggressiveness at dusk following the spawning period. The simple study design adopted may be applied to other contexts, aiming to the recognition of several levels of fish vulnerability to angling.  相似文献   
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Measurements of the tissue accumulation of α-amino[1-14C]isobutyrate [1-14C]AIB) in lean (+/?) and obese (fa/fa) Zucker rats showed an augmented tissue/plasma ratio in the liver of the obese animals. In contrast, brown adipose tissue AIB accumulation was lower in the fa/fa animals. In response to a 24h starvation period AIB accumulation was significantly elevated in the liver and plasma of the lean animals and was unchanged in the liver of the fa/fa animals. The circulating concentration of alanine and branched-chain amino acids was elevated in the fa/fa animals as compared to their lean counterparts. These observations suggest that amino acid uptake is not involved in the impaired muscle development observed in the obese Zucker rat and that the ability of brown adipose tissue for amino acid utilization is decreased in the obese animals suggesting that this may partially explain the impaired thermoregulatory capacity observed in brown adipose tissue of obese Zucker rats.  相似文献   
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Summary The obtention of embryogenic competence in Actinidia deliciosa var. deliciosa cv. Hayward is reported. Axillary buds from shoots submitted to cold (4°C) and starvation for 1.5 months, developed leaves with embryogenic competence. These leaves, cultured in darkness for 1.5 months on a medium containing zeatin as a sole growth regulator, originated compact structures from which embryos developed. The plating orientation and sectioning of leaves strongly affected the expression of the embryogenic potential. A selected fraction of the protoplasts isolated from these leaves was able to develop in an embryogenic way. The germination of the embryos is still only occasional.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - 2-iP 6-dimethylallyl aminopurine - IAA indole-3-acetic acid - NOA naphthoxyacetic acid - SEM Scanning Electron Microscopy  相似文献   
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Chloramphenicol acetyl transferase (CAT) gene was used as a reporter gene to assess the conditions for polyethylene glycol (PEG)-mediated transfection of kiwifruit protoplasts. The effect of plasmid concentration and the presence of carrier DNA were each assessed by analysing CAT activity in transfected protoplasts using thin-layer chromatography (TLC) autoradiographic detection of acetylated chloramphenicol. A gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) non-radioactive method was developed for monitoring CAT gene activity. This method provides a high speed of analysis (30 min) and precise means of detecting acetylated products at the nanomolar level, enabling quantification at very low transfection rates. Using this method we optimized plasmid and PEG concentration and also assessed the effect of heat shock on transfection. The best CAT activity was obtained using 30% polyethylene glycol 4000 and by submitting protoplasts to heat shock (45 °C, 5 min) prior to transfection.  相似文献   
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The genetic basis of bacteriocin (Bac) production by six strains of Staphylococcus aureus was examined. Gene transfer experiments (in which the plasmids were tagged with the erythromycin resistance transposon Tn551) and plasmid-elimination experiments by growth at 43 degrees C associated bacteriocin production with a particular plasmid in each strain. The Bac plasmids could be separated into two distinct groups: the first comprised plasmids larger than 40 kb, which did not specify immunity to bacteriocins; the second comprised small plasmids (8.0-10.4 kb) which also specified immunity to bacteriocins. The sequence relations among the small plasmids (pRJ6, pRJ9, pRJ10 and pRJ11) were investigated by comparing restriction enzyme digest patterns and by hybridization. Plasmids pRJ10 and pRJ11 were indistinguishable and very closely related to plasmid pRJ9. Plasmid pRJ6, although different from the others, shared regions of sequence homology with them. No homology was found between plasmids pRJ6 or pRJ9 and the large Bac plasmids.  相似文献   
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Summary Effects of three solution aluminium concentrations (0, 25, and 100M) on nitrogen fixation by well-nodulated plants ofStylosanthes hamata, Stylosanthes humilis andStylosanthes scabra are reported. Plants were inoculated with Rhizobium CB756 and grown for 21 days in an aluminium-free nutrient solution at pH 5.3 before imposition of the aluminium treatments.Nitrogen fixation was measured both by the increase in total nitrogen content of the plants and acetylene reduction in roots of plants harvested at 10 and 20 days after imposition of the aluminium treatments. Solution aluminium concentrations as high as 100M, had no detrimental effect on nitrogen fixation in any species.  相似文献   
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