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51.
A urease test for the rapid determination of urea hydrolysis is described in which diluted urea agar concentrate was used in small amounts with dense inoculum of the test organisms. The method was evaluated and compared with Christensen's urea agar slants by using 728 clinical isolates of gram-negative bacteria. Of the 325 strains of urease-positive Proteus-Providencia-Morganella, 282 (87%) gave positive results within 5 min with the rapid test. Urease activity of 97% of these organisms became evident within 30 min. All 287 isolates which showed no urease activity on Christensen's urea agar also remained negative by this test.  相似文献   
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The impact of trace elements, especially zinc, selenium, copper, and magnesium, on male fertility has gained great interest and significance. Increased oxidative stress and altered trace element levels are probable etiological factors underlying male reproductive dysfunction and infertility. The present study focused on the evaluation of seminal oxidative markers, such as reactive oxygen species (ROS), malondialdehyde (MDA), and total antioxidant capacity (TAC), and trace element levels in the normozoospermic fertile control group (n = 40) and asthenozoospermic infertile group (n = 30). Semen from infertile men exhibited significantly higher ROS and MDA levels accompanied with significant decline in TAC and trace element (zinc and magnesium) levels. Furthermore, a significant correlation was observed between trace elements and oxidative markers with sperm motility. The current study revealed increased lipid peroxidation and oxidant-reductant imbalance that leads to deterioration of semen quality and male infertility. Thus, oxidative stress and trace elements can be considered important biomarkers of male infertility. Measurement of seminal oxidative stress with conventional seminological parameters must be integrated in fertility assessment from early stages to ensure healthy semen characteristics and fertility in men.  相似文献   
55.
The greater wax moth, Galleria mellonella, is one of the most ruinous pests of honeycomb in the world. Beta‐glucosidases are a type of digestive enzymes that hydrolytically catalyzes the beta‐glycosidic linkage of glycosides. Characterization of the beta‐glucosidase in G. mellonella could be a significant stage for a better comprehending of its role and establishing a safe and effective control procedure primarily against G. mellonella and also some other insect pests. Laboratory reared final instar stage larvae were randomly selected and homogenized for beta‐glucosidase activity assay and subsequent analysis. The enzyme was purified to apparent homogeneity by salting out with ammonium sulfate and using sepharose‐4B‐l ‐tyrosine‐1‐naphthylamine hydrophobic interaction chromatography. The purification was 58‐fold with an overall enzyme yield of 29%. The molecular mass of the protein was estimated as ca. 42 kDa. The purified beta‐glucosidase was effectively active on para/ortho‐nitrophenyl‐beta‐d ‐glucopyranosides (p‐/o‐NPG) with Km values of 0.37 and 1.9 mM and Vmax values of 625 and 189 U/mg, respectively. It also exhibits different levels of activity against para‐nitrophenyl‐β‐d ‐fucopyranoside (p‐NPF), para/ortho‐nitrophenyl β‐d ‐galactopyranosides (p‐/o‐NPGal) and p‐nitrophenyl 1‐thio‐β‐d ‐glucopyranoside. The enzyme was competitively inhibited by beta‐gluconolactone and also was very tolerant to glucose against p‐NPG as substrate. The Ki and IC50 values of δ‐gluconolactone were determined as 0.021 and 0.08 mM while the enzyme was more tolerant to glucose inhibition with IC50 value of 213.13 mM for p‐NPG.  相似文献   
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We describe here successful designs of strong inhibitors for porcine pancreatic elastase (PPE) and Streptomyces griseus protease B (SGPB). For each enzyme two inhibitor variants were designed. In one, the reactive site residue (position 18) was retained and the best residues were substituted at contact positions 13, 14, and 15. In the other variant the best residues were substituted at all contact positions except the reactive site where a Gly was substituted. The four designed variants were: for PPE, T13E14Y15-OMTKY3 and T13E14Y15G18M21P32V36-OMTKY3, and for SGPB, S13D14Y15-OMTKY3 and S13D14Y15G18I19K21-OMTKY3. The free energies of association (ΔG0) of expressed variants have been measured with the proteases for which they were designed as well as with five other serine proteases and the results are discussed.  相似文献   
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Mucosal apoptosis has been demonstrated to be an essential pathological feature in portal hypertensive gastropathy (PHG). p53-upregulated modulator of apoptosis (PUMA) was identified as a BH3-only Bcl-2 family protein that has an essential role in apoptosis induced by a variety of stimuli, including endoplasmic reticulum (ER) stress. However, whether PUMA is involved in mucosal apoptosis in PHG remains unclear, and whether PUMA induces PHG by mediating ER stress remains unknown. The aim of the study is to investigate whether PUMA is involved in PHG by mediating ER stress apoptotic signaling. To identify whether PUMA is involved in PHG by mediating ER stress, gastric mucosal injury and apoptosis were studied in both PHG patients and PHG animal models using PUMA knockout (PUMA-KO) and PUMA wild-type (PUMA-WT) mice. The induction of PUMA expression and ER stress signaling were investigated, and the mechanisms of PUMA-mediated apoptosis were analyzed. GES-1 and SGC7901 cell lines were used to further identify whether PUMA-mediated apoptosis was induced by ER stress in vitro. Epithelial apoptosis and PUMA were markedly induced in the gastric mucosa of PHG patients and mouse PHG models. ER stress had a potent role in the induction of PUMA and apoptosis in PHG models, and the apoptosis was obviously attenuated in PUMA-KO mice. Although the targeted deletion of PUMA did not affect ER stress, mitochondrial apoptotic signaling was downregulated in mice. Meanwhile, PUMA knockdown significantly ameliorated ER stress-induced mitochondria-dependent apoptosis in vitro. These results indicate that PUMA mediates ER stress-induced mucosal epithelial apoptosis through the mitochondrial apoptotic pathway in PHG, and that PUMA is a potentially therapeutic target for PHG.  相似文献   
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Background

The possible role of viruses in breast cancer etiology remains an unresolved question. We hypothesized that if some viruses are involved, it may be in a subgroup of breast cancers only. Epidemiological arguments drove our interest in breast cancer subgroups that are more frequent in Africa, namely inflammatory breast cancer (IBC) and triple-negative breast cancer. We tested whether viral prevalence was significantly higher in these subgroups.

Materials and Methods

One hundred fifty-five paraffin-embedded malignant breast tumors were randomly selected at the pathology laboratory of the University Hospital of Annaba (Algeria) to include one third of IBC and two thirds of non-IBC. They were tested for the presence of DNA from 61 viral agents (46 human papillomaviruses, 10 polyomaviruses, and 5 herpesviruses) using type-specific multiplex genotyping assays, which combine multiplex PCR and bead-based Luminex technology.

Results

Viral DNA was found in 22 (17.9%) of 123 tumors. The most prevalent viruses were EBV1 and HPV16. IBC tumors carried significantly more viruses (any type) than non-IBC tumors (30% vs. 13%, p<0.04). Similarly, triple-negative tumors displayed higher virus-positivity than non-triple-negative tumors (44% vs. 14%, p<0.009).

Conclusions

Our results suggest an association between the presence of viral DNA and aggressive breast cancer phenotypes (IBC, triple-negative). While preliminary, they underline the importance of focusing on subgroups when studying viral etiology in breast cancer. Further studies on viruses in breast cancer should be conducted in much larger samples to confirm these initial findings.  相似文献   
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To study the pharmacophore properties of quinazolinone derivatives as 5HT(7) inhibitors, 3D QSAR methodologies, namely Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) were applied, partial least square (PLS) analysis was performed and QSAR models were generated. The derived model showed good statistical reliability in terms of predicting the 5HT(7) inhibitory activity of the quinazolione derivative, based on molecular property fields like steric, electrostatic, hydrophobic, hydrogen bond donor and hydrogen bond acceptor fields. This is evident from statistical parameters like q(2) (cross validated correlation coefficient) of 0.642, 0.602 and r(2) (conventional correlation coefficient) of 0.937, 0.908 for CoMFA and CoMSIA respectively. The predictive ability of the models to determine 5HT(7) antagonistic activity is validated using a test set of 26 molecules that were not included in the training set and the predictive r(2) obtained for the test set was 0.512 & 0.541. Further, the results of the derived model are illustrated by means of contour maps, which give an insight into the interaction of the drug with the receptor. The molecular fields so obtained served as the basis for the design of twenty new ligands. In addition, ADME (Adsorption, Distribution, Metabolism and Elimination) have been calculated in order to predict the relevant pharmaceutical properties, and the results are in conformity with required drug like properties.  相似文献   
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