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891.
Karl H. Engesser W. Fietz P. Fischer P. Schulte Hans-J. Knackmuss 《FEMS microbiology letters》1990,69(3):317-321
A bacterial strain, Pseudomonas sp. POB 310, was enriched with 4-carboxy biphenyl ether as sole source of carbon and energy. Resting cells of POB 310 co-oxidize a substrate analogue, 4-carboxybenzophenone, yielding 1,2-dihydro-1,2-dihydroxy-4-carboxy-benzophenone. The ether bond of 3- and 4-carboxy biphenyl ether is cleaved analogously by initial 1,2-dioxygenation, yielding a hemiacetal which is hydrolysed to protocatechuate and phenol. These intermediates are degraded via an ortho and meta pathway, respectively. Alternative 2,3- and 3,4-dioxygenation can be ruled out as triggering steps in carboxy biphenyl ether degradation. 相似文献
892.
Binding of coagulation factors IX and X to the endothelial cell surface 总被引:13,自引:0,他引:13
Bovine coagulation factors IX and X bind to independent sites on bovine aortic endothelial cells. Binding studies with cells maintained serum-free showed that there are at least two classes of binding sites for factor IX and factor X with a dissociation constant of 4.9 x 10(-9) M and 2.1 x 10(-8) M for the respective high affinity sites. Ca+2 was required for specific binding and was reversed by addition of EDTA or EGTA. Competition experiments showed that factor IX and factor IXa bind to the same sites, which are different from the factor X binding sites. Neither binding of factor IX or factor X is inhibited by addition of prothrombin or protein C. Indirect immunofluorescence of factor IX indicated that binding was diffuse on the cell surface. 相似文献
893.
Heartwood extractives of C. dupreziana were investigated. Carvacrol methyl ether, cedrol and α-cedrene are present, together with sesquiterpene hydrocarbons. A comparison is made with those found in C. sempervirens and other Cupressus species. 相似文献
894.
Paul K.T. Persson 《Chemistry and physics of lipids》1984,34(4):287-299
The polymorphic behaviour of a series of l-O-alkylglycerols have been studied; mainly by DTA and X-ray powder diffraction techniques. The behaviour of these ether lipids is quite similar to that of the closely related l-acylglycerols. The background to the polymorphic behaviour of these lipids is discussed. In the α-phase, the alkyl chains are non-crystalline but still partly ordered in a lattice. The main reason for the formation of the sub-α-phase is a ‘chain crystallization’. The polar group region in the sub-α-phase is crystallized in a state with higher energy, relative to the state of the polar group region in the β-phase. This can account for the difference in stability the β - and sub-ga-phases. 相似文献
895.
896.
The effect of farnesyl methyl ether, a mimic of insect juvenile hormone, on Hymenolepis diminuta in vitro. International journal for Parasitology4: 211–218. The inhibition of weight gain of Hymenolepis diminuta in vitro by farnesyl methyl ether (FME) was not dose-dependent, so that there were no differences produced by FME in concentrations from 10?5 to 10?13m. At all concentrations of FME used the weight gain over a 6-day culture period was half of that of controls. The FME-treated and control worms were identical to each other in proglottid number and the degree of maturity. Neither the dry to wet weight ratios of worms nor the carbohydrate, protein or lipid ratios were altered by FME. The release of neurosecretory material from the neurosecretory cells in the rostellum (as measured by the degree of their fuchsinophilia) was more advanced in time in the FME-treated worms than in the controls, and it is suggested that this premature release of neurosecretion, triggered either directly or indirectly by traces of FME in the medium, upset a control mechanism in the germinative tissue of the neck region, which determines the mass, but not the number, of the proglottids in the strobila. 相似文献
897.
Simona LoBasso Patrizia LoPalco Giuseppe Mascolo Angela Corcelli 《Archaea (Vancouver, B.C.)》2008,2(3):177-183
The lipid composition of the extremely halophilic archaeon
Haloquadratum walsbyi was investigated by thin-layer
chromatography and electrospray ionization-mass spectrometry. The
analysis of neutral lipids showed the presence of vitamin MK-8,
squalene, carotene, bacterioruberin and several retinal isomers. The
major polar lipids were phosphatidylglycerophosphate methyl ester,
phosphatidylglycerosulfate, phosphatidylglycerol and sulfated
diglycosyl diether lipid. Among cardiolipins, the tetra-phytanyl or
dimeric phospholipids, only traces of bisphosphatidylglycerol were
detected. When the cells were exposed to hypotonic medium, no changes
in the membrane lipid composition occurred. Distinguishing it from
other extreme halophiles of the Halobacteriaceae
family, the osmotic stress did not induce the
neo-synthesis of cardiolipins in H. walsbyi. The
difference may depend on the three-laminar structure of the cell wall,
which differs significantly from that of other Haloarchaea. 相似文献
898.
899.
Chinensinaphthol and chinensinaphihol methyl ether, two new 1-ary]-2,3-naphthalide lignans, have been isolated from the title plant. Structures (2) and (3) have been established for them by chemical transformations and spectral evidence. Significant quantitative variations in the content of the cyclic and the acyclic lactonic lignans (1–3, 5–7) of P. chinensis have been observed in plant material, collected from the same locality and examined in 3 consecutive years. 相似文献
900.