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1.
D. M. MacLaren F. Namavar A. M. J. J. Verweij-Van Vught W. A. C. Vel J. A. Kaan 《Antonie van Leeuwenhoek》1984,50(5-6):775-787
In this article we review our researches into the pathogenesis of mixed infections. These may conveniently be divided into
in vitro and in vivo studies.
In vitro we confirmed that interference with the killing of aerobes by polymorphonuclear leucocytes (PMN’s) is a property
of theBacteroides strains tested and appears to depend on competition for opsonins i.e. complement factors. Further studies are in progress
to define which complement factors and which bacterial structures are involved. The influence ofB. fragilis on chemotaxis has also been studied. Our preliminary data suggest thatB. fragilis is itself poorly chemotactic and reduces the chemoattractivity ofProteus mirabilis. This observation is surprising when we consider that abscess formation is the hall-mark ofB. fragilis infections and needs clarification.
In vivo we have developed a skin infection model in mice which is economical and gives reproducible and quantitative results.
In this model we have demonstrated pathogenic synergy betweenEscherichia coli andB. fragilis. Further studies are planned to assess the role of complement and bacterial factors in this in vivo synergy. 相似文献
2.
Markus de Raad Kaan Koper Kai Deng Benjamin P. Bowen Hiroshi A. Maeda Trent R. Northen 《The Journal of biological chemistry》2023,299(3)
Aminotransferases (ATs) catalyze pyridoxal 5′-phosphate–dependent transamination reactions between amino donor and keto acceptor substrates and play central roles in nitrogen metabolism of all organisms. ATs are involved in the biosynthesis and degradation of both proteinogenic and nonproteinogenic amino acids and also carry out a wide variety of functions in photorespiration, detoxification, and secondary metabolism. Despite the importance of ATs, their functionality is poorly understood as only a small fraction of putative ATs, predicted from DNA sequences, are associated with experimental data. Even for characterized ATs, the full spectrum of substrate specificity, among many potential substrates, has not been explored in most cases. This is largely due to the lack of suitable high-throughput assays that can screen for AT activity and specificity at scale. Here we present a new high-throughput platform for screening AT activity using bioconjugate chemistry and mass spectrometry imaging–based analysis. Detection of AT reaction products is achieved by forming an oxime linkage between the ketone groups of transaminated amino donors and a probe molecule that facilitates mass spectrometry-based analysis using nanostructure-initiator mass spectrometry or MALDI–mass spectrometry. As a proof-of-principle, we applied the newly established method and found that a previously uncharacterized Arabidopsis thaliana tryptophan AT-related protein 1 is a highly promiscuous enzyme that can utilize 13 amino acid donors and three keto acid acceptors. These results demonstrate that this oxime–mass spectrometry imaging AT assay enables high-throughput discovery and comprehensive characterization of AT enzymes, leading to an accurate understanding of the nitrogen metabolic network. 相似文献
3.
Yılmaz Baş Nermin Koç Kaan Helvacı Cem Koçak Raşit Akdeniz Havva Hande Keser Şahin 《Translational oncology》2021,14(2):100994
We investigated programmed cell death 1 (PD-1) / programmed cell death ligand 1 (PD-L1) expression in high grade serous ovarian cancer (HGSOC) and its relationship to tumor infiltrating lymphocytes (TIL) and prognosis. Formalin fixed paraffin embedded (FFPE) samples of 94 HGSOC cases were included in the study. Immunohistochemical analysis (CD3, CD4, CD8, PD-1 and PD-L1) was performed. Samples were analyzed for expression of immune proteins in the peritumoral stromal and intratumoral areas, scored, and expression was correlated with overall survival, stage, and age. PD-L1 staining ratio with a score greater than 0 was found to have lower survival. There were two positive staining patterns, patchy/diffuse and patchy/focal patterns, in 24 (25.5%) cases. Considering the threshold value ≥5%, we demonstrated that the PD-L1 positive cancer cell membrane immunoreactivity rate and patchy/diffuse PD-L1 expression were 9.6% (n = 9). There was statistically significant relationship between high PD-1 scores and PD-L1 cases of ≥ 5%. A statistically significant difference was found between PD-L1 staining and survival in patients with a threshold ≥ 5%. However an appropriate rate for treatment was determined in 9.6% cases. There was a statistically significant correlation between PD-1 positive TIL score and intratumoral CD3, peritumoral stromal CD3, intratumoral CD4 and intratumoral CD8 positive cells. Survival was lower in cases with higher PD-L1 positive stromal TIL score. 相似文献
4.
Background
Keratins 8 and 18 (K8/K18) are intermediate filament proteins that protect the liver from various forms of injury. Exonic K8/K18 variants associate with adverse outcome in acute liver failure and with liver fibrosis progression in patients with chronic hepatitis C infection or primary biliary cirrhosis. Given the association of K8/K18 variants with end-stage liver disease and progression in several chronic liver disorders, we studied the importance of keratin variants in patients with hemochromatosis.Methods
The entire K8/K18 exonic regions were analyzed in 162 hemochromatosis patients carrying homozygous C282Y HFE (hemochromatosis gene) mutations. 234 liver-healthy subjects were used as controls. Exonic regions were PCR-amplified and analyzed using denaturing high-performance liquid chromatography and DNA sequencing. Previously-generated transgenic mice overexpressing K8 G62C were studied for their susceptibility to iron overload. Susceptibility to iron toxicity of primary hepatocytes that express K8 wild-type and G62C was also assessed.Results
We identified amino-acid-altering keratin heterozygous variants in 10 of 162 hemochromatosis patients (6.2%) and non-coding heterozygous variants in 6 additional patients (3.7%). Two novel K8 variants (Q169E/R275W) were found. K8 R341H was the most common amino-acid altering variant (4 patients), and exclusively associated with an intronic KRT8 IVS7+10delC deletion. Intronic, but not amino-acid-altering variants associated with the development of liver fibrosis. In mice, or ex vivo, the K8 G62C variant did not affect iron-accumulation in response to iron-rich diet or the extent of iron-induced hepatocellular injury.Conclusion
In patients with hemochromatosis, intronic but not exonic K8/K18 variants associate with liver fibrosis development. 相似文献5.
Demirogullari B Cirak MY Poyraz A Sonmez K Kulah C Turkyilmaz Z Karabulut R Yilmaz Y Basaklar AC Kale N 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2003,135(3):249-255
Lactulose and lactitol, non-absorbable disaccharides, prevent bacterial translocation (BT) arising from the gut. In contrast, lack of food into the gut leads to coliform bacterial overgrowth and even if it does not cause BT, can induce the risk from other stimuli for BT. In this study, we tested whether lactulose and lactitol affected populations of coliform bacteria in the caecum during starvation in Sprague-Dawley rats. Three groups of rats were starved for 72 h and given oral 2 ml undiluted lactulose (670 mg/ml), 2 ml undiluted lactitol (666 mg/ml) or 2 ml physiological saline, respectively, once a day. The caecum and mesenteric lymph nodes (MLNs) were removed for microbiological and histopathological analyses. The highest degree of coliform bacterial overgrowth, BT to MLNs and histopathological damage were observed in lactulose-treated rats, followed by the group treated with lactitol. As a result of this study, both drugs, especially lactulose augmented the proliferation and translocation tendency of coliform bacteria in the caecum during 72-h starvation in rats. 相似文献
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8.
Effect of extracellular enzyme activity on digestion performance of mesophilic UASB reactor treating high-strength municipal wastewater 总被引:1,自引:0,他引:1
Turkdogan-Aydinol FI Yetilmezsoy K Comez S 《Bioprocess and biosystems engineering》2011,34(4):389-401
Effect of extracellular enzyme activity on digestion performance of up-flow anaerobic sludge blanket (UASB) reactor was investigated
for enhancement of anaerobic treatability of municipal wastewater. Two identical UASB reactors (9 L), namely Reactor-A (without
enzyme addition) and Reactor-B (with enzyme addition), were simultaneously operated at mesophilic conditions (32 ± 2 °C) with
a hydraulic retention time of 24 h. Preliminary test results showed that the highest total chemical oxygen demand (TCOD) removal
were achieved with an extracellular enzyme dosage of 0.2 mL/L. In the activation period of the extracellular enzyme (on days
186–212), while Reactor-A removed up to 69.3% of TCOD and 55.9% of soluble chemical oxygen demand (SCOD), Reactor-B effectively
removed up to 81.9% of TCOD and 72.2% of SCOD. The average VFA/alkalinity ratios were determined to be about 0.40 (±0.03)
and 0.28 (±0.08) for Reactor-A and Reactor-B, respectively. 相似文献
9.
Lacombe S Kaan F Léger S Bervillé A 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》2001,324(9):839-845
All the [HOAC] lines derived from the Pervenets mutant carry a specific RFLP (oleHOS) revealed by an oleate desaturase cDNA used as a probe. The [LO] (linoleic) genotypes do not carry oleHOS, but another allele: oleLOR. We studied [HOAC] heredity in two segregating populations. In an F2 population, the [HOAC] trait co-segregated with oleHOS. In a recombinant inbred line F6 population, all [HOAC] RI lines carried oleHOS. The RI lines carrying oleHOS were either [LO] or [HOAC]. The absence of [HOAC] RI lines with oleLOR eliminated the occurrence of a recombination event between the locus carrying oleHOS and the locus carrying Pervenets allele. The [HOAC] trait is due to 2 independent loci: the locus carrying oleHOS allele and another locus. One allele at this other locus may suppress the effect of oleHOS allele on the [HOAC] trait. The existence of this suppressor allele has only been suggested for sunflower. 相似文献
10.
Christine Fauth Hongen Zhang Stephanie Harabacz Jill Brown Kaan Saracoglu Gaby Lederer Olaf Rittinger Imma Rost Roland Eils Lyndal Kearney Michael R. Speicher 《Human genetics》2001,109(6):576-583
We present a new strategy for the detection of subtelomeric rearrangements. This approach is based on two hybridizations with different probe sets. The first set consists of microdissected subtelomeric probes (each 5-10 megabases in size) labeled combinatorially employing 7 different fluorochromes. With this set, subtelomeric interchromosomal exchanges can be detected in a 24-color experiment. The second set comprises a second generation of subtelomeric PAC-, P1- and BAC-clones. Probes for p- and q-arms are labeled with two different colors. This second set detects small deletions; in addition it provides regional information, so that translocated material identified by the first probe set can be assigned to the p- or q-arm of a chromosome. The test has been evaluated in a blind study on a series of subtle translocations and deletions. 相似文献