Design,Synthesis, Characterization and Computational Studies of Mannich Bases Oxadiazole Derivatives as New Class of Jack Bean Urease Inhibitors

Mannich bases consisting of 1,3,4-oxadiazole-2-thione ( 3 a – 3 l ) bearing various substituents were synthesized and found potent jack bean urease inhibitors. The prepared compounds showed significantly good inhibitory activities with IC₅₀ values from 9.45±0.05 to 267.42±0.23 μM. The compound 3 k containing 4-chlorophenyl (−R) and 4-hydroxyphenyl (−R′) was most active with IC₅₀ 9.45±0.05 μM followed by 3 e (IC₅₀ 22.52±0.15 μM) in which −R was phenyl and −R′ was isopropyl group. However, when both −R and −R′ were either 4-chlorophenyl groups ( 3 l ) or only −R′ was 4-nitrophenyl ( 3 i ), both compounds were found inactive. The detailed binding affinities of the produced compounds with protein were explored through molecular docking and data-supported in-vitro enzyme inhibition profiles. Drug likeness was confirmed by in silico ADME investigations and molecular orbital analysis (HOMO-LUMO) and electrostatic potential maps were got from DFT calculations. ESP maps exposed that there are two potential binding sites with the most positive and most negative parts.     

Cys303 in the histidine kinase PhoR is crucial for the phosphotransfer reaction in the PhoPR two-component system in Bacillus subtilis

The PhoPR two-component system activates or represses Pho regulon genes to overcome a phosphate deficiency. The Pho signal transduction network is comprised of three two-component systems, PhoPR, ResDE, and Spo0A. Activated PhoP is required for expression of ResDE from the resA promoter, while ResD is essential for 80% of Pho induction, establishing a positive feedback loop between these two-component systems to amplify the signal received by the Pho system. The role of ResD in the Pho response is via production of terminal oxidases. Reduced quinones inhibit PhoR autophosphorylation in vitro, and it was proposed that the expression of terminal oxidases leads to oxidation of the quinone pool, thereby relieving the inhibition. We show here that the reducing environment generated by dithiothreitol (DTT) in vivo inhibited Pho induction in a PhoR-dependent manner, which is in agreement with our previous in vitro data. A strain containing a PhoR variant, PhoR(C303A), exhibited reduced Pho induction and remained sensitive to inhibition by DTT, suggesting that the mechanisms for Pho reduction via PhoR(C303A) and DTT are different. PhoR and PhoR(C303A) were similar with regard to cellular concentration, limited proteolysis patterns, rate of autophosphorylation, stability of PhoR approximately P, and inhibition of autophosphorylation by DTT. Phosphotransfer between PhoR approximately P or PhoR(C303A) approximately P and PhoP occurred rapidly; most label from PhoR approximately P was transferred to PhoP, but only 10% of the label from PhoR(C303A) approximately P was associated with PhoP, while 90% was released as inorganic phosphate. No difference in PhoP approximately P or PhoR autophosphatase activity was observed between PhoR and PhoR(C303A) that would explain the release of inorganic phosphate. Our data are consistent with a role for PhoR(C303) in PhoR activity via stabilization of the phosphoryl-protein intermediate(s) during phosphotransfer from PhoR approximately P to PhoP, which is stabilization that is required for efficient production of PhoP approximately P.     

Hairpin DNAzymes: a new tool for efficient cellular gene silencing

BACKGROUND: RNA-based gene silencing is potentially a powerful therapeutic strategy. Catalytic 10-23 DNAzymes bind to target RNA by complimentary sequence arms on a Watson-Crick basis and thus can be targeted to effectively cleave specific mRNA species. However, for in vivo applications it is necessary to stabilise DNAzymes against nucleolytic attack. Chemical modifications can be introduced into the binding arms to increase stability but these may alter catalytic activity and in some cases increase cell toxicity. METHODS: We designed novel 10-23 DNAzyme structures that incorporate stem-loop hairpins at either end on the DNAzyme binding arms. The catalytic activity of hairpin DNAzymes (hpDNAzyme) were tested in vitro against 32P-labelled cRNA encoding the muscle acetylcholine receptor (AChR) alpha-subunit. Resistance of hpDNAzymes to nucleolytic degradation was tested by incubation of the hpDNAzymes with Bal-31, DNase1 or HeLa cell extract. Gene silencing by hpDNAzymes was assessed by measuring reduced fluorescence from DsRed2 and EGFP reporters in cell culture systems, and reduced 125I-alpha-bungarotoxin binding in cells transfected with cDNA encoding the AChR. RESULTS: We show that hpDNAzymes show remarkable resistance to nucleolytic degradation, and demonstrate that in cell culture systems the hpDNAzymes are far more effective than standard 10-23 DNAzymes in down-regulating protein expression from target mRNA species. CONCLUSION: hpDNAzymes provide new molecular tools that, without chemical modification, give highly efficient gene silencing in cells, and may have potential therapeutic applications.     

Current status of lupus genetics

Over the past 40 years more than 100 genetic risk factors have been defined in systemic lupus erythematosus through a combination of case studies, linkage analyses of multiplex families, and case-control analyses of single genes. Multiple investigators have examined patient cohorts gathered from around the world, and although we doubt that all of the reported associations will be replicated, we have probably already discovered many of the genes that are important in lupus pathogenesis, including those encoding human leukocyte antigen-DR, Fcγ receptor 3A, protein tyrosine phosphatase nonreceptor 22, cytotoxic T lymphocyte associated antigen 4, and mannose-binding lectin. In this review we will present what is known, what is disputed, and what remains to be discovered in the world of lupus genetics.     

Texture analysis of liver fibrosis microscopic images: a study on the effect of biomarkers

Chronic hepatic injury results in liver fibrosis with eventual progression to irreversible cirrhosis. Liver fibrogenesis involves the activation of the quiescent hepatic stellate cell into an activated myofibroblast that is characterized by α-smooth muscle actin (α-SMA) expression and the production of collagens (types I and III). In the present study, rats were randomly divided into three groups: (i) control group, where rats were only treated with a vehicle; (ii) fibrosis group, where rats were treated with carbon tetrachloride (CCl(4)) to induce liver fibrosis; and (iii) silymarin group, where rats were protected with silymarin during CCl(4) treatment. Rats were sacrificed and sections of liver tissue were counterstained with hematoxylin and eosin and Masson's trichrome. Other sections were immunostained using collagens and α-SMA primary antibodies. Fibrosis was confirmed using serum marker measurements. Microscopic images of the stained sections were acquired and digitized. The Biomarker Index of Fibrosis (BIF) was calculated from the images by quantifying the percentage of stained fibers. Statistical methods of texture analysis (TA), namely co-occurrence and run-length matrices, were applied on the digital images followed by classification using agglomerative hierarchical clustering and linear discriminant analysis with cross validation. TA applied on different biomarkers was successful in discriminating between the groups, showing 100% sensitivity and specificity for classification between the control and fibrosis groups using any biomarker. Some classification attempts showed dependence on the biomarker used, especially for classification between the silymarin and fibrosis groups, which showed optimal results using Masson's trichrome. TA results were consistent with both BIF and serum marker measurements.     

Synthesis and in vitro behavior of β-TCP zirconia/polymeric biocomposites for bio-applications

Novel biocomposites were fabricated by impregnating β-tricalcium phosphate (β-TCP)/zirconia particles into the polymers matrix. The composite materials were characterized using thermo-gravimetric analysis (TGA), X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR) analyzes and Scanning Electron Microscopy (SEM). The results confirmed the conversion of hydroxyapatite (HA) to β-TCP at a sintering temperature of 1150 °C with or without zirconia powder. The in vitro behavior was assessed via measurement of calcium and phosphorus ions in SBF (simulated body fluid). FT-IR and SEM of the composites were performed pre and post immersion in SBF. The results prove that the bone like apatite layer formation was enhanced on the β-TCP-Z20/polymeric composite surface more than that on the β-TCP-Z10/polymeric composite. Therefore, the data confirmed that zirconia plays an important role in the enhancement of the apatite formation. The conclusions proved that the β-TCP-Z20/polymeric biocomposites, containing 20% of zirconia, are promising for bone remodeling applications.     

Characterization of fertility alteration and marker validation for male sterility genes in novel PTGMS lines hybrid rice

Photoperiod and thermosensitive genetic male sterile (PTGMS) lines have become one of the main sources of global rice production increasing. This study was conducted to evaluate the fertility alteration and validate the male sterility genes using validation markers in novel Egyptian Indica and Japonica PTGMS lines under natural conditions. The study revealed that the new genetic male sterile lines belong to the type of photo–thermosensitive genetic male sterility (PTGMS). The fertility alteration of these lines has influenced by photoperiod and temperature interaction. The new PTGMS lines have three sensitive periods of fertility alteration; transformation, sterility, and fertility period. Furthermore, the sensitive stage of fertility transformation might be from secondary branch primordial to pollen mother cells (PMC) meiosis. Under the natural Sakha condition, the new PTGMS lines were stable sterile under the condition of day length upper 13,75 h and temperature over 25 °C, while its convert to fertile under day length under 13 h, and temperature lower than 24 °C. The co-dominant markers identified the pms3 and tms5 genes in the new PTGMS lines, indicated that the fertility alteration in these lines controlled by photoperiod and thermosensitive stages.     

Chemopreventive activities of Trigonella foenum graecum (Fenugreek) against breast cancer

Cancer is the second leading cause of death worldwide. Conventional therapies cause serious side effects and, at best, merely extend the patient's lifespan by a few years. Cancer control may therefore benefit from the potential that resides in alternative therapies. There is thus an increasing demand to utilize alternative concepts or approaches to the prevention of cancer. In this report, we show a potential protective effect of Fenugreek seeds against 7,12-dimethylbenz(alpha)anthracene (DMBA)-induced breast cancer in rats. At 200 mg/kg b.wt., Fenugreek seeds' extract significantly inhibited the DMBA-induced mammary hyperplasia and decreased its incidence. Epidemiological studies also implicate apoptosis as a mechanism that might mediate the Fenugreek's anti-breast cancer protective effects. To our knowledge, this is the first study that suggests significant chemopreventive effects of Fenugreek seeds against breast cancer.