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971.
972.
973.
Rolf Henrik Nilsson Martin Ryberg Kessy Abarenkov Elisabet Sjökvist & Erik Kristiansson 《FEMS microbiology letters》2009,296(1):97-101
In a previous work, it was observed that the swarming of polyamine-deficient Proteus mirabilis ( speB :: sm ) was severely inhibited on Luria–Bertani (LB) swarming plates (LBSw) (LB, 0.5% glucose, 0.5% agar), and it was clarified that extracellular putrescine was important as a signaling molecule for the induction of swarming in P. mirabilis . However, a polyamine-deficient strain (delta- speAB delta- speC ) of Escherichia coli swarmed as well as the parental strain on LBSw plates. We report that the swarming phenotype of a polyamine-deficient E. coli strain is dependent on spermidine and PotABCD, a spermidine importer. 相似文献
974.
Forty-nine patients with decreased fibrinolytic activity in the vessel walls or a decreased release mechanism, or both, were treated with ethyloestrenol for three to 17 months. Forty-five of the patients had had recurrent, phlebographically verified, deep venous thrombosis (DVT) and four had arterial thrombosis. Ethyloestrenol 8 mg/day was given to 31 patients and 4 mg/day was given to 12. The remaining six patients had been treated with a combination of phenformin and ethloestrenol. The phenformin was withdrawn but they were kept on ethyloestrenol 8 mg/day. Another 15 patients with a normal fibrinolytic system--four with recurrent DVT and 11 with severe arteriosclerosis--were given ethyloestrenol 8 mg/day. The spontaneous fibrinolytic activity, local fibrinolytic activity during standardised venous occlusion of the arms, and fibrinolytic activity of the vessel walls increased significantly after treatment with ethyloestrenol 8 mg/day for three months. No further increase occurred after three months, and ethyloestrenol 4 mg/day had no effect. No values rose significantly in the patients with a normal fibrinolytic system. One patient suffered a recurrence within three months of treatment, before the fibrinolytic system became normal. In one patient the fibrinolytic defect reappeared after 10 months in spite of continued treatment. Two of the three women of fertile age developed irregular cycles and intermenstrual bleeding, which disappeared when the treatment was withdrawn. No other side effects were observed. 相似文献
975.
To establish a suitable experimental system for studies of the interaction of retinol-binding protein (RBP) with transthyretin (TTR) we have expressed the corresponding cDNAs in HeLa cells. To investigate whether complex formation might occur already in the endoplasmic reticulum (ER), the C-terminal ER retention signal, KDEL, was attached to TTR. The tetrameric TTR-KDEL fusion protein was retained in the ER of HeLa cells. When RBP was co-expressed with TTR-KDEL, RBP was retained intracellularly. A cDNA-encoding purpurin, a protein which is 50% identical to RBP, was then expressed together with TTR-KDEL. Purpurin was not retained intracellularly and did not bind to TTR coupled to Sepharose. The effect of the vitamin A status on the secretion of TTR and RBP was examined. While TTR expressed alone was not retained intracellularly, TTR was retained in vitamin A-deficient cells when co-expressed with RBP. Addition of retinol stimulated rapid secretion of both proteins. These results demonstrate that TTR can form a complex with RBP in the ER. The data suggest that RBP and TTR are secreted as a complex. 相似文献
976.
L. Anders Nilsson 《Nordic Journal of Botany》1983,3(2):157-179
Interactions between Orchis mascula L. ssp. mascula and anthophilous insects were studied mainly on the island of Öland, Sweden. The species is nectarless and acts by deceiving various bees (Hymenoptera, Apoidea). Temporary seeking/exploratory drives of bees for food–sources were exploited by means of superiority in floral display. A floral reflectance maximum at 440 nm (blue) largely determines the colour in the visual spectrum of bees. The floral scent is composed to about 90% of mono–terpenes. Nothing suggested mimesis of concurrent food–flowers either in colour or in scent. Anthesis covered a time period in late spring when (a) concurrent food–flowers for bees were rather few, (b) many bumble–bee queens (Bombus Latr. spp.) were inexperienced as regards food–flowers and had no foraging routines, (c) cuckoo bumble–bee females (Psithyrus Lep. spp.) recovery–fed on flowers after hibernation, (d) males of Eucera longicornis (L.) (Anthophoridae) patrolled far out from their nest–area, and when (e) many solitary bee species flew about. The pollinator fauna differed between sites, viz. either Bombus queens, Psithyrus females or E. longicornis males transported the majority of the pollinaria. The pollination system does not seem to be stabilised in the study areas. Floral morphology indicates that the plant's anthecological specialisation to bees as a group implies a graded unspecialisation to each species of bee in the legitimate pollinator group. 相似文献
977.
Sara Debecker Maarten De Jonge Philippe Lambret Viktor Nilsson‐Örtman Lieven Bervoets Robby Stoks 《Global Change Biology》2013,19(9):2625-2633
Global warming and contamination represent two major threats to biodiversity that have the potential to interact synergistically. There is the potential for gradual local thermal adaptation and dispersal to higher latitudes to mitigate the susceptibility of organisms to contaminants and global warming at high latitudes. Here, we applied a space‐for‐time substitution approach to study the thermal dependence of the susceptibility of Ischnura elegans damselfly larvae to zinc in a common garden warming experiment (20 and 24 °C) with replicated populations from three latitudes spanning >1500 km in Europe. We observed a striking latitude‐specific effect of temperature on the zinc‐induced mortality pattern; local thermal adaptation along the latitudinal gradient made Swedish, but not French, damselfly larvae more susceptible to zinc at 24 °C. Latitude‐ and temperature‐specific differences in zinc susceptibility may be related to the amount of energy available to defend against and repair damage since Swedish larvae showed a much stronger zinc‐induced reduction of food intake at 24 °C. The pattern of local thermal adaptation indicates that the predicted temperature increase of 4 °C by 2100 will strongly magnify the impact of a contaminant such as zinc at higher latitudes unless there is thermal evolution and/or migration of lower latitude genotypes. Our results underscore the critical importance of studying the susceptibility to contaminants under realistic warming scenarios taking into account local thermal adaptation across natural temperature gradients. 相似文献
978.
Matti Marklund Rikard Landberg Per Åman Afaf Kamal-Eldin 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(11-12):888-894
Alkylresorcinols (ARs) are phenolic lipids present at high concentrations in the outer parts of rye and wheat kernels and have been proposed as biomarkers for intake of whole grain and bran products of these cereals. AR are absorbed in the small intestine and after hepatic metabolism two major metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA), are excreted in urine either as such or as conjugates. Urine samples from nine individuals were incubated with different enzymes to assess type and extent of conjugates. In comparison with DHBA, which was mostly found in the free form, the less polar DHPPA was conjugated to a greater extent and the major conjugates were glucuronides. In this method, urine samples were hydrolyzed using β-glucuronidase from Helix pomatia and syringic acid was used as internal standard. Samples, silylated with BSTFA, were analyzed by GC–MS utilizing a BP-5 fused silica capillary column and single ion monitoring of molecular ions (m/z 370 [DHBA], m/z 398 [DHPPA]). Recoveries of DHBA and DHPPA were estimated to be 94% and 93%, respectively. The average intra-assay/inter-assay coefficients of variation were 4.9/5.7% for DHBA and 7.6/9.3% for DHPPA. 相似文献
979.
980.