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91.
The eosinophil cationic protein (ECP) is a human antimicrobial protein involved in the host immune defense that belongs to the pancreatic RNase A family. ECP displays a wide range of antipathogen activities. The protein is highly cationic and its bactericidal activity is dependant on both cationic and hydrophobic surface exposed residues. Previous studies on ECP by site-directed mutagenesis indicated that the RNase activity is not essential for its bactericidal activity. To further understand the ECP bactericidal mechanism, we have applied enzymatic and chemical limited cleavage to search for active sequence determinants.Following a search for potential peptidases we selected the Lys-endoproteinase, which cleaves the ECP polypeptide at the carboxyl side of its unique Lys residue, releasing the N-terminal fragment (0-38).Chemical digestion using cyanogen bromide released several complementary peptides at the protein N-terminus. Interestingly, ECP treatment with cyanogen bromide represents a new example of selective chemical cleavage at the carboxyl side of not only Met but also Trp residues. Recombinant ECP was denatured and carboxyamidomethylated prior to enzymatic and chemical cleavage. Irreversible denaturation abolishes the protein bactericidal activity.The characterization of the digestion products by both enzymatic and chemical approaches identifies a region at the protein N-terminus, from residues 11 to 35, that retains the bactericidal activity. The most active fragment, ECP(0-38), is further compared to ECP derived synthetic peptides. The region includes previously identified stretches related to lipopolysaccharide binding and bacteria agglutination. The results contribute to define the shortest ECP minimized version that would retain its antimicrobial properties. The data suggest that the antimicrobial RNase can provide a scaffold for the selective release of cytotoxic peptides. 相似文献
92.
Capture–recapture techniques have been used for considerable time to predict population size. Estimators usually rely on frequency counts for numbers of trappings; however, it may be the case that these are not available for a particular problem, for example if the original data set has been lost and only a summary table is available. Here, we investigate techniques for specific examples; the motivating example is an epidemiology study by Mosley et al., which focussed on a cholera outbreak in East Pakistan. To demonstrate the wider range of the technique, we also look at a study for predicting the long-term outlook of the AIDS epidemic using information on number of sexual partners. A new estimator is developed here which uses the EM algorithm to impute unobserved values and then uses these values in a similar way to the existing estimators. The results show that a truncated approach – mimicking the Chao lower bound approach – gives an improved estimate when population homogeneity is violated. 相似文献
93.
94.
E. Jortzik M. Farhadi R. Ahmadi K. Tóth J. Lohr B.M. Helmke S. Kehr A. Unterberg I. Ott R. Gust V. Deborde E. Davioud-Charvet R. Réau K. Becker C. Herold-Mende 《Biochimica et Biophysica Acta - Proteins and Proteomics》2014,1844(8):1415-1426
Glioblastoma, an aggressive brain tumor, has a poor prognosis and a high risk of recurrence. An improved chemotherapeutic approach is required to complement radiation therapy. Gold(I) complexes bearing phosphole ligands are promising agents in the treatment of cancer and disturb the redox balance and proliferation of cancer cells by inhibiting disulfide reductases. Here, we report on the antitumor properties of the gold(I) complex 1-phenyl-bis(2-pyridyl)phosphole gold chloride thio-β-d-glucose tetraacetate (GoPI-sugar), which exhibits antiproliferative effects on human (NCH82, NCH89) and rat (C6) glioma cell lines. Compared to carmustine (BCNU), an established nitrosourea compound for the treatment of glioblastomas that inhibits the proliferation of these glioma cell lines with an IC50 of 430 μM, GoPI-sugar is more effective by two orders of magnitude. Moreover, GoPI-sugar inhibits malignant glioma growth in vivo in a C6 glioma rat model and significantly reduces tumor volume while being well tolerated. Both the gold(I) chloro- and thiosugar-substituted phospholes interact with DNA albeit more weakly for the latter. Furthermore, GoPI-sugar irreversibly and potently inhibits thioredoxin reductase (IC50 4.3 nM) and human glutathione reductase (IC50 88.5 nM). However, treatment with GoPI-sugar did not significantly alter redox parameters in the brain tissue of treated animals. This might be due to compensatory upregulation of redox-related enzymes but might also indicate that the antiproliferative effects of GoPI-sugar in vivo are rather based on DNA interaction and inhibition of topoisomerase I than on the disturbance of redox equilibrium. Since GoPI-sugar is highly effective against glioblastomas and well tolerated, it represents a most promising lead for drug development. This article is part of a Special Issue entitled: Thiol-Based Redox Processes. 相似文献
95.
Aneta Ksi??ek Karol Zub Paulina A. Szafrańska Monika Wieczorek Marek Konarzewski 《Biology letters》2014,10(12)
Despite its presumed significance, the association between immune defence, energy expenditures and overwinter survival is rarely studied. We analysed individual variation in immunocompetence quantified as neutrophil-to-lymphocyte ratio (N/L), total white blood cells (WBC) and natural antibody levels, along with resting (RMR) and peak metabolic rates (PMR) and mortality during three consecutive winter seasons in a natural population of the root vole, Microtus oeconomus. In early winter, WBC count was negatively correlated with RMR, whereas N/L ratio was negatively correlated with swim-elicited PMR. We suggest that while the first correlation reflected the trade-off between energy allocation in immunocompetence and other metabolically demanding processes, the latter correlation stemmed from stress-induced immunosuppression elicited by the necessity to cope with swimming in frequently flooded habitat. In addition, the analysis carried out during the first year of study characterized by a high population density and prevalence of infestation with a blood parasite—Babesia spp., showed that its intensity was inversely correlated with the N/L ratio. In summary, our results suggest that elevated N/L ratio increases the winter survival of free-ranging rodents by increasing their ability to cope with parasitic infections. 相似文献
96.
Zhengdong Xu Yehong Gong Jiaqian Wan Jiaxing Tang Qingwen Zhang 《Cell stress & chaperones》2021,26(5):799
HSPB5 (heat shock protein B5), also known as αB-crystallin, is one of the most widespread and populous of the ten human small heat shock proteins (sHsps). Over the past decades, extensive research has been conducted on HSPB5. However, few studies have statistically analyzed these publications. Herein, we conducted a bibliometric analysis to track the global research trend and current development status of HSPB5 research from the Web of Science Core Collection (WoSCC) database between 1985 and 2020. Our results demonstrate that 1220 original articles cited 54,778 times in 391 scholarly journals were published. Visualization analyses reveal that the Journal of Biological Chemistry was the most influential journal with 85 articles. The USA dominated this field with 520 publications (42.62%), followed by Japan with 149 publications (12.21%), and Kato contributed the largest number of publications. Most related publications were published in journals focusing on biochemistry molecular biology, cell biology, neurosciences neurology, and ophthalmology. In addition, keyword co-occurrence analyses identify three predominant research topics: expression of HSPB5, chaperone studies for HSPB5, and pathological studies of HSPB5. This study provides valuable guidance for researchers and leads to collaborative opportunities between diverse research interests to be integrated for HSPB5 research.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12192-021-01220-6. 相似文献
97.
L. A. Shchur A. D. Aponasenko V. P. Ladygina V. N. Lopatin G. V. Makarskaya 《Microbiology》2000,69(4):466-470
Some characteristics of bacterioplankton—generation time, daily (P) and specific (P/B) bacterioplankton production, and bacterial metabolic coefficientK
2—in the loess-containing Lake Khanka were determined using five modifications of the bacterial-count procedure with the fluorescent
dyes fluorescamin and erythrosin. Experiments showed that the organomineral complex (OMC) in this lake is broken down by chemoorganoheterotrophic
bacteria. The increase in the loess content of the lake water intensified bacterial growth and the cycles of potassium, silicon,
and other biogenic elements. The addition of starch to a loess suspension activated the breakdown of OMC due to the adsorption
of starch on the OMC/water interface and stimulation of the metabolism of attached bacteria. 相似文献
98.
On autocorrelation in a Poisson regression model 总被引:3,自引:0,他引:3
99.
100.
《Reproductive biology》2014,14(3):176-181
In the present study, we evaluated the clinical value of the following parameters: basal anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), inhibin B and antral follicle count (AFC) in predicting live birth outcomes. The study involved 603 women undergoing in vitro fertilization (IVF) using the long protocol for controlled ovarian hyperstimulation (COH). Serum levels of AMH, FSH and inhibin B as well as AFC were measured on the first three days of the menstrual cycle prior to the beginning of stimulation. AMH was the only independent parameter that correlated with the chance of live birth. We found that live birth rates of 46.2% (patient age <35 years), 44.7% (35–37 years), 32.1% (38–39) and 15.3% (>39) were associated with concentrations of AMH > 1.4 ng/ml. For the AMH range 0.6–1.4 ng/ml, the live birth rates were 29.3%, 12.5%, 5.6% and 2.7%, respectively, and for AMH concentrations below 0.6 ng/ml the rates were 7.1%, 8.3%, 0% and 5.8%, respectively. Independently of other parameters affecting the chance of live birth, the success rate was the highest when the AMH level was >2 ng/ml, significantly lower when the AMH concentration was about 1 ng/ml, and 0% when the AMH concentration was ∼0.1 ng/ml. In conclusion, this is the first report to demonstrate that AMH level correlated better than age, FSH or inhibin B concentrations or AFC with live birth outcome. Therefore, the basal serum concentration of AMH may become a new, substantial prognostic factor regarding live birth above and beyond other currently available predictors of IVF outcome. 相似文献