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51.
Lubbert Dijkhuizen Lex de Boer Roelof H. Boers Wim Harder Wil N. Konings 《Archives of microbiology》1982,133(4):261-266
Cytoplasmic membrane vesicles were prepared by a lysozyme-salt treatment from Arthrobacter P1 grown on methylamine as the carbon and energy source. In the presence of an ascorbate-phenazine methosulphate electron donor system, these vesicles accumulated methylamine in unmodified form by an inducible transport system. This system has a high affinity for methylamine (Kapp=20–25 M). The effect of the ionophores valinomycin and nigericin combined with membrane potential () and pH-gradient (pH) measurements demonstrated that methylamine uptake is electrogenic and driven by the . Optimal activity is observed at pH 6.5 and 30°C. Methylamine uptake was not affected by the presence of ammonium ions but was inhibited by the primary amines ethylamine (competitively), propylamine, butylamine and benzylamine. In addition, formaldehyde and acetate, at a concentration of 1 mM, inhibited methylamine uptake almost completely. These compounds were shown to be non-competitive inhibitors. A strong inhibition observed in the presence of plumbagin could be relieved by addition of dithiothreitol. This indicates that the oxidation-reduction state of, probably, carrier dithiol-disulfide-groups is an important factor in methylamine translocation in Arthrobacter P1. 相似文献
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Biodiversity-based identification and functional characterization of the mannose-specific adhesin of Lactobacillus plantarum 下载免费PDF全文
Pretzer G Snel J Molenaar D Wiersma A Bron PA Lambert J de Vos WM van der Meer R Smits MA Kleerebezem M 《Journal of bacteriology》2005,187(17):6128-6136
Lactobacillus plantarum is a frequently encountered inhabitant of the human intestinal tract, and some strains are marketed as probiotics. Their ability to adhere to mannose residues is a potentially interesting characteristic with regard to proposed probiotic features such as colonization of the intestinal surface and competitive exclusion of pathogens. In this study, the variable capacity of 14 L. plantarum strains to agglutinate Saccharomyces cerevisiae in a mannose-specific manner was determined and subsequently correlated with an L. plantarum WCFS1-based genome-wide genotype database. This led to the identification of four candidate mannose adhesin-encoding genes. Two genes primarily predicted to code for sortase-dependent cell surface proteins displayed a complete gene-trait match. Their involvement in mannose adhesion was corroborated by the finding that a sortase (srtA) mutant of L. plantarum WCFS1 lost the capacity to agglutinate S. cerevisiae. The postulated role of these two candidate genes was investigated by gene-specific deletion and overexpression in L. plantarum WCFS1. Subsequent evaluation of the mannose adhesion capacity of the resulting mutant strains showed that inactivation of one candidate gene (lp_0373) did not affect mannose adhesion properties. In contrast, deletion of the other gene (lp_1229) resulted in a complete loss of yeast agglutination ability, while its overexpression quantitatively enhanced this phenotype. Therefore, this gene was designated to encode the mannose-specific adhesin (Msa; gene name, msa) of L. plantarum. Domain homology analysis of the predicted 1,000-residue Msa protein identified known carbohydrate-binding domains, further supporting its role as a mannose adhesin that is likely to be involved in the interaction of L. plantarum with its host in the intestinal tract. 相似文献
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Transcriptional organization and dynamic expression of the hbpCAD genes, which encode the first three enzymes for 2-hydroxybiphenyl degradation in Pseudomonas azelaica HBP1 下载免费PDF全文
Jaspers MC Schmid A Sturme MH Goslings DA Kohler HP Roelof Van Der Meer J 《Journal of bacteriology》2001,183(1):270-279
54.
Intraoperative Fluid Restriction in Pancreatic Surgery: A Double Blinded Randomised Controlled Trial
Ganapathy van Samkar Wietse J. Eshuis Roelof J. Bennink Thomas M. van Gulik Marcel G. W. Dijkgraaf Benedikt Preckel Stefan de Hert Dirk J. Gouma Markus W. Hollmann Olivier R. C. Busch 《PloS one》2015,10(10)
Background
Perioperative fluid restriction in a variety of operations has shown improvement of: complications, recovery of gastrointestinal function and length of stay (LOS). We investigated effects of crystalloid fluid restriction in pancreatic surgery. Our hypothesis: enhanced recovery of gastrointestinal function.Methods
In this double-blinded randomized trial, patients scheduled to undergo pancreatoduodenectomy (PD) were randomized: standard (S:10ml/kg/hr) or restricted (R:5ml/kg/hr) fluid protocols. Primary endpoint: gastric emptying scintigraphically assessed on postoperative day 7.Results
In 66 randomized patients, complications and 6-year survival were analyzed. 54 patients were analyzed in intention to treat: 24 S-group and 30 R-group. 32 patients actually underwent a PD and 16 patients had a palliative gastrojejunostomy bypass operation in the full protocol analysis. The median gastric emptying time (T½) was 104 minutes (S-group, 95% confidence interval: 74–369) versus 159 minutes (R-group, 95% confidence interval: 61–204) (P = 0.893, NS). Delayed gastric emptying occurred in 10 patients in the S-group and in 13 patients in the R-group (45% and 50%, P = 0.779, NS). The primary outcome parameter, gastric emptying time, did not show a statistically significant difference between groups.Conclusion
A fluid regimen of 10ml/kg/hr or 5ml/kg/hr during pancreatic surgery did not lead to statistically significant differences in gastric emptying. A larger study would be needed to draw definite conclusions about fluid restriction in pancreatic surgery.Trial registration
ISRCTN62621488 相似文献55.
Daniela Herrera Moro Chao Wouter W. Kallemeijn Andre R. A. Marques Marie Orre Roelof Ottenhoff Cindy van Roomen Ewout Foppen Maria C. Renner Martina Moeton Marco van Eijk Rolf G. Boot Willem Kamphuis Elly M. Hol Jan Aten Hermen S. Overkleeft Andries Kalsbeek Johannes M. F. G. Aerts 《PloS one》2015,10(9)
Gaucher disease is characterized by lysosomal accumulation of glucosylceramide due to deficient activity of lysosomal glucocerebrosidase (GBA). In cells, glucosylceramide is also degraded outside lysosomes by the enzyme glucosylceramidase 2 (GBA2) of which inherited deficiency is associated with ataxias. The interest in GBA and glucosylceramide metabolism in the brain has grown following the notion that mutations in the GBA gene impose a risk factor for motor disorders such as α-synucleinopathies. We earlier developed a β-glucopyranosyl-configured cyclophellitol-epoxide type activity based probe (ABP) allowing in vivo and in vitro visualization of active molecules of GBA with high spatial resolution. Labeling occurs through covalent linkage of the ABP to the catalytic nucleophile residue in the enzyme pocket. Here, we describe a method to visualize active GBA molecules in rat brain slices using in vivo labeling. Brain areas related to motor control, like the basal ganglia and motor related structures in the brainstem, show a high content of active GBA. We also developed a β-glucopyranosyl cyclophellitol-aziridine ABP allowing in situ labeling of GBA2. Labeled GBA2 in brain areas can be identified and quantified upon gel electrophoresis. The distribution of active GBA2 markedly differs from that of GBA, being highest in the cerebellar cortex. The histological findings with ABP labeling were confirmed by biochemical analysis of isolated brain areas. In conclusion, ABPs offer sensitive tools to visualize active GBA and to study the distribution of GBA2 in the brain and thus may find application to establish the role of these enzymes in neurodegenerative disease conditions such as α-synucleinopathies and cerebellar ataxia. 相似文献
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Kumari R Tecon R Beggah S Rutler R Arey JS van der Meer JR 《Environmental microbiology》2011,13(10):2808-2819
Long-chain alkanes are a major component of crude oil and therefore potentially good indicators of hydrocarbon spills. Here we present a set of new bacterial bioreporters and assays that allow to detect long-chain alkanes. These reporters are based on the regulatory protein AlkS and the alkB1 promoter from Alcanivorax borkumensis SK2, a widespread alkane degrader in marine habitats. Escherichia coli cells with the reporter construct reacted strongly to octane in short-term (6 h) aqueous suspension assays but very slightly only to tetradecane, in line with what is expected from its low water solubility. In contrast, long-term assays (up to 5 days) with A. borkumensis bioreporters showed strong induction with tetradecane and crude oil. Gel-immobilized A. borkumensis reporter cells were used to demonstrate tetradecane and crude oil bioavailability at a distance from a source. Alcanivorax borkumensis bioreporters induced fivefold more rapid and more strongly when allowed physical contact with the oil phase in standing flask assays, suggesting a major contribution of adhered cells to the overall reporter signal. Using the flask assays we further demonstrated the effect of oleophilic nutrients and biosurfactants on oil availability and degradation by A. borkumensis. The fluorescence signal from flask assays could easily be captured with a normal digital camera, making such tests feasible to be carried out on, e.g. marine oil responder vessels in case of oil accidents. 相似文献
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