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排序方式: 共有533条查询结果,搜索用时 15 毫秒
1.
Richard B. Pouw Mieke C. Brouwer Judy Geissler Laurens V. van Herpen Sacha S. Zeerleder Walter A. Wuillemin Diana Wouters Taco W. Kuijpers 《PloS one》2016,11(3)
The major human complement regulator in blood, complement factor H (FH), has several closely related proteins, called FH-related (FHR) proteins. As all FHRs lack relevant complement regulatory activity, their physiological role is not well understood. FHR protein 3 (FHR-3) has been suggested to compete with FH for binding to Neisseria meningitidis, thereby affecting complement-mediated clearance. Clearly, the in vivo outcome of such competition greatly depends on the FH and FHR-3 concentrations. While FH levels have been established, accurate FHR-3 levels were never unequivocally reported to date. Moreover, CFHR3 gene copy numbers commonly vary, which may impact the FHR-3 concentration. Hence, we generated five anti-FHR-3 mAbs to specifically measure FHR-3 in human healthy donors of which we determined the gene copy number variation at the CFH/CFHR locus. Finally, we examined the acute-phase response characteristics of FHR-3 in a small sepsis cohort. We determined FHR-3 levels to have a mean of 19 nM and that under normal conditions the copy number of CFHR3 correlates to a very large extent with the FHR-3 serum levels. On average, FHR-3 was 132-fold lower compared to the FH concentration in the same serum samples and FHR-3 did not behave as a major acute phase response protein. 相似文献
2.
W. J. Middelhoven Mieke C. Hoogkamer-Te Niet W. T. A. M. De Laat C. Weijers C. J. E. A. Bulder 《Antonie van Leeuwenhoek》1986,52(6):525-535
The maximum growth rate of Trichosporon cutaneum CBS 8111 in chemostat cultures was 0.185 h-1 on ethylamine and 0.21 h-1 on butylamine, that of Candida famata CBS 8109 was 0.32 h-1 on putrescine.The amine oxidation pattern of the ascomycetous strains studied, viz. Candida famata CBS 8109, Stephanoascus ciferrii CBS 4856 and Trichosporon adeninovorans CBS 8244 was independent of the amine that had been used as the growth substrate. It resembled that of benzylamine/putrescine oxidase found in other ascomycetous yeasts. However, differences in pH optimum and substrate specificity were observed between the amine-oxidizing systems of these three species.The amine oxidation pattern of cell-free extracts of Trichosporon cutaneum CBS 8111 varied with the amine that was used as growth substrate. The enzyme system produced by Cryptococcus laurentii CBS 7140 failed to oxidize isobutylamine and benzylamine, and showed a high pH optimum.The synthesis of amine oxidase in the four yeast strains studied was not repressed by ammonium chloride and was weakly repressed by glucose but was strongly repressed if both compounds were present in the growth medium. 相似文献
3.
Inhibitory Effects of Secondary Metabolites from the Red Alga Delisea pulchra on Swarming Motility of Proteus mirabilis 下载免费PDF全文
L. Gram R. de Nys R. Maximilien M. Givskov P. Steinberg S. Kjelleberg 《Applied microbiology》1996,62(11):4284-4287
Abnormal, uncoordinated swarming motility of the opportunistic human pathogen Proteus mirabilis was seen when a crude extract of the Australian red alga Delisea pulchra was added to the medium. This occurred at concentrations at which growth rate, swimming motility, cell elongation, polynucleation, and hyperflagellation were not affected. One halogenated furanone from D. pulchra inhibited swarming motility at concentrations that did not affect growth rate and swimming motility. Other structurally similar D. pulchra furanones had no effect on swarming, suggesting considerable specificity in the effects of furanones on swarming motility by P. mirabilis. 相似文献
4.
Two major problems associated with biofouling studies are the lack of broad scale testing and failure to use consistent standards among different assays or studies. To address these issues the activity of two biologically active natural products, elatol and deschloroelatol, isolated from the marine red alga Laurencia rigida, and three commonly used biocides, Nopcocide N-96?, Irgarol 1051? and Sea-Nine 211?, was compared, in a broad spectrum of bioassays. The activity of the different compounds varied substantially among different bioassay tests. Elatol and deschloroelatol had a narrow range of activity with strongest effects against invertebrate larvae. Both compounds were highly toxic. However, neither compound had strong activity against marine bacteria or the common epiphyte Ulva lactuca. Irgarol 1051 also had a narrow range of activity, only affecting algal settlement strongly. Nopcocide N-96 and Sea-Nine 211 had moderate to strong activity across the spectrum of bioassays, viz. growth of marine bacteria (Vibrio fischeri, Serratia sp.), inhibition of settlement of macroalgae (Ulva lactuca), toxicity (Balanus amphitrite), and inhibition of settlement of invertebrate larvae (Balanus amphitrite, Bugula neritina). Based on the results it is proposed that Sea-Nine 211, because of its broad spectrum activity, be used as a standard for comparative assessments of the antifouling activity of marine natural products and analogues. 相似文献
5.
Molecular cloning of a gene involved in glucose sensing in the yeast Saccharomyces cerevisiae 总被引:6,自引:1,他引:5
Linda Van Aelst Stefan Hohmann Botchaka Bulaya Wim de Koning Laurens Sierkstra Maria José Neves Kattie Luyten Rafael Alijo José Ramos Paola Coccetti Enzo Martegani Neuza Maria de Magalhães-Rocha Rogelio Lopes Brandão Patrick Van Dijck Mieke Vanhalewyn Peter Durnez Arnold W. H. Jans Johan M. Thevelein 《Molecular microbiology》1993,8(5):927-943
6.
Mieke Blows 《The Australian journal of anthropology》1981,13(2):149-163
Testart's hypothesis is placed in historical perspective. The Kaiabara case study, prominent in Testart's paper but of illustrative significance rather than as proof in his book, is discussed. Testart's mathematical analysis of the degree of coherence between the classifications of societies with patrimoieties as against those with matrimoieties provides an interesting means of reaching inferences about the evolution of social organization, although the required quantification involves some difficulties. Testart's further major contribution to the understanding of moiety organization is his proposed principle of classification based on the violator/non-violator diachotomy. He shows this principle to be more consistent with matrilineal than with patrilineal classifications. It is argued that the Eagle-Crow Myth, from which Testart derives the violator-non-violator diachotomy, refers to the Oedipal conflict, and that this is related to the formation of matrilineal moieties. It is further suggested that the taboo on blood, central to the ‘violator’ concept, is connected with matrilineality. 相似文献
7.
Willy J. Peumans Hetty M. Stinissen Mieke Tierens Albert R. Carlier 《Plant cell reports》1982,1(5):212-214
Cell-free extracts from dry wheat (Triticum vulgare L.) and rye (Secale cereale L.) embryos do not synthesize their corresponding lectins when incubated under conditions optimalized for translation of either exogenous or endogenous mRNA. Only when the extracts are prepared and incubated in the complete absence of sulphydryl containing compounds lectins are synthesized in vitro. Since immunoprecipitation techniques could not demonstrate unequivocally the presence of lectin among the cell-free translation products a specific affinity purification procedure has been developed in order to proof the presence of stored lectin mRNAs in dry wheat and rye embryos.Abbreviations DTT
dithiothreitol
- SDS-PAGE
sodium dodecyl sulphate polyacrylamide gel electrophoresis
- TCA
trichloracetic acid 相似文献
8.
The equilibrium parameters of the hydrolysis of ampicillin catalysed by penicillin amidase were determined within the pH range of 4.5 to 5.5. The values of the ionization constants of the carboxy group of D-(-)-ALPHA-AMINOPHENYLACETIC ACID (PK1=1.80) and amino group of 6-aminopenicillanic acid (pK2=4.60) were estimated and pH-dependence of the effective free energy of ampicillin hydrolysis was calculated. It was shown that the thermodynamic optimum of ampicillin synthesis was at 3.20 (the value of the effective free energy under the experimental conditions was 3.27 kcal/mole). The value of the "true", pH-independent free energy of hydrolysis (deltasigma) of the amide bond in the ampicillin molecule was determined to be equal to 9.72 kcal/mole. The thermodynamic parameters of ampicillin and benzylpenicillin hydrolysis were compared. The amino group in the alpha-position of phenylacetic acid was shown to have a significant effect on the values of "true" free energy of hydrolysis of the penicillin amide bond and free ionization energy in the system. 相似文献
9.
Equilibrium distribution of phenacetyl-D-(--)-alpha-aminophenylacetic acid obtained on fermentative hydrolysis of D,L-aminophenylacetic acid in a two-phase system (chloroform-water) was studied within a wide range of the substance concentration in the organic phase. It was shown than in the organic phase the distributing substance formed associates. The empirical equation: y = A + Bx describing the dependence of the effective distribution of the non-dissociated form of phenylacetyl-D-(--)-alpha-aminophenylacetic acid on its concentration in the organic phase was suggested. Coefficients A and B of the equation were determined and an equation for evaluating equilibrium concentrations in the equeous phase was suggested. On the basis of the studies an extraction-polarometric method for quantitative determination of phenacetyl-D-(--)-alpha-aminophenylacetic acid concentration was developed. The method consists of extraction of the non-dissociated form of phenylacetyl-D-(--)-alpha-aminophenylacetic acid with chloroform, determination of the equilibrium concentration of the distributing substance in the organic phase by the polarimetric method and subsequent estimation of the equilibrium and initial concentrations of the electrolyte in the aqueous phase. 相似文献
10.
Properties of penicillinamidase (PA) covalently bound with the cellulose matrix were studied. The efficiency of the binding depended on the bind type and purity of the native enzyme taken for binding. Stability of the immobilized PA (IPA) was studied at wide pH ranges. The effect of the ion strength, substrate concentration and purity of the native PA on stability of IPA was also investigated. The maximum stability of the enzyme was observed at pH 6.5-7.0 Stability of IPA depended on the purity of the native enzyme. When PA of the diazotized ether of cellulose containing amino groups was used, the enzyme was destabilized. IPA prepared on chlortriazinylcellulose was more stable than the respective native PA almost by I order. 相似文献