Structure-activity relationship of uridine-based nucleoside phosphoramidate prodrugs for inhibition of dengue virus RNA-dependent RNA polymerase

To identify a potent and selective nucleoside inhibitor of dengue virus RNA-dependent RNA polymerase, a series of 2′- and/or 4′-ribose sugar modified uridine nucleoside phosphoramidate prodrugs and their corresponding triphosphates were synthesized and evaluated. Replacement of 2′-OH with 2′-F led to be a poor substrate for both dengue virus and human mitochondrial RNA polymerases. Instead of 2′-fluorination, the introduction of fluorine at the ribose 4′-position was found not to affect the inhibition of the dengue virus polymerase with a reduction in uptake by mitochondrial RNA polymerase. 2′-C-ethynyl-4′-F-uridine phosphoramidate prodrug displayed potent anti-dengue virus activity in the primary human peripheral blood mononuclear cell-based assay with no significant cytotoxicity in human hepatocellular liver carcinoma cell lines and no mitochondrial toxicity in the cell-based assay using human prostate cancer cell lines.     

Synthesis and evaluation of thiomannosides,potent and orally active FimH inhibitors

FimH is a type I fimbrial lectin located at the tip of type-1 pili of Gram-negative uropathogenic Escherichia coli (UPEC) guiding its ability to adhere and infect urothelial cells. Accordingly, blocking FimH with small molecule inhibitor is considered as a promising new therapeutic alternative to treat urinary tract infections caused by UPEC. Herein, we report that compounds having the S-glycosidic bond (thiomannosides) had improved metabolic stability and plasma exposures when dosed orally. Especially compound 5h showed the potential to inhibit biofilm formation and also to disrupt the preformed biofilm. And compound 5h showed prophylactic effect in UTI model in mice.     

Terminal drought and seed priming improves drought tolerance in wheat

Plants retain the preceding abiotic stress memory that may aid in attainment of tolerance to subsequent stresses. This study was conducted to evaluate the influence of terminal drought memory (drought priming) and seed priming in improving drought tolerance in wheat (Triticum aestivum L.). During first growing season, wheat was planted in field under optimal (well-watered) and drought stress imposed at reproductive stage (BBCH growth stage 49) until maturity (BBCH growth stage 83). Seeds collected from both sources were subjected to hydropriming or osmopriming (with 1.5% CaCl₂ solution); while, dry seed was taken as control. Treated and control seeds, from both sources, were sown in soil filled pots. After the completion of seedling emergence, pots were maintained at 50% water holding capacity (drought) or 100% water holding capacity (well-watered). Drought stress suppressed the plant growth (2–44%), perturbed water relations (1–18%) and reduced yield (192%); however, osmolytes accumulation (3–14%) and malondialdehyde contents (26–29%) were increased under drought. The crop raised from the seeds collected from terminal drought stressed plants had better growth (5–63%), improved osmolyte accumulation (13–45%), and lower lipid peroxidation (3%) than the progeny of well-watered crop. Seed priming significantly improved the crop performance under drought stress as compared to control. However, osmopriming was more effective than hydropriming in this regard as it improved leaf area (9–43%), tissue water status (2–47%), osmolytes accumulation (6–48%) and grain yield (14–79%). In conclusion, terminal drought induced modifications in seed composition and seed priming improved transgenerational drought tolerance through improvement in tissue water status and osmolytes accumulation, and decrease in lipid peroxidation.     

In silico study of carvone derivatives as potential neuraminidase inhibitors

Recent outbreaks of highly pathogenic influenza strains have highlighted the need to develop new anti-influenza drugs. Here, we report an in silico study of carvone derivatives to analyze their binding modes with neuraminidase (NA) active sites. Two proposed carvone analogues, CV(A) and CV(B), with 36 designed ligands were predicted to inhibit NA (PDB ID: 3TI6) using molecular docking. The design is based on structural resemblance with the commercial inhibitor, oseltamivir (OTV), ligand polarity, and amino acid residues in the NA active sites. Docking simulations revealed that ligand A18 has the lowest energy binding (?G_bind) value of ?8.30 kcal mol^-1, comparable to OTV with ?G_bind of ?8.72 kcal mol^-1. A18 formed seven hydrogen bonds (H-bonds) at residues Arg292, Arg371, Asp151, Trp178, Glu227, and Tyr406, while eight H-bonds were formed by OTV with amino acids Arg118, Arg292, Arg371, Glu119, Asp151, and Arg152. Molecular dynamics (MD) simulation was conducted to compare the stability between ligand A18 and OTV with NA. Our simulation study showed that the A18-NA complex is as stable as the OTV-NA complex during the MD simulation of 50 ns through the analysis of RMSD, RMSF, total energy, hydrogen bonding, and MM/PBSA free energy calculations.     

Amplification of rfbE and fliC Genes by Polymerase Chain Reaction for Identification and Detection of Salmonella Serovar Enteritidis,Dublin and Gallinarum-Pullorum

Polymerase chain reaction (PCR) primers for O9 antigen (rfbE) and phase 1 flagellin antigen (fliC) were designed for the rapid identification and detection of Salmonella serovar Enteritidis and Dublin. The rfbE primer pairs selectively amplified the rfbE region of group O9 Salmonella serovars. The fliC primer pairs amplified the DNAs of g,m and g,p-type flagellar antigen; Salmonella serovar Enteritidis, Dublin, and Essen. However, DNA from flagellar-negative Salmonella serovar Gallinarum-Pullorum was also amplified. The sensitivity of PCR primer pairs was 10 CFU/assay by boiled DNA preparation and 10² CFU/assay by proteinase K-treated DNA preparation.     

Purification and Characterization of Camel Thyroglobulin

Thyroglobulin (669 kDa), the major protein of the camel thyroid, has been isolated and purified from saline extract of the gland by ammonium sulfate fractionation and DEAE-cellulose chromatography. Ultracentrifugal analysis of the purified material, with an iodine content of 0.39%, showed a major and minor component with S_20,w values of 17 and 24, respectively. Separation of the protein from thyroid of individual animals by linear salt gradient on DEAE-cellulose showed a major and minor peak, indicating heterogeneity. Native gel electrophoresis of camel thyroglobulin showed a doublet, revealing microheterogeneity. A similar pattern was observed for the slower migrating components (24 S iodoprotein). N-terminal analysis of the purified protein revealed asparagine as the major N-terminal amino acid. Glycine and alanine were observed as the minor N-terminals. No differences in N-terminals between the major and minor peak were observed. Camel thyroglobulin, as thyroglobulin of other animal species, is a glycoprotein with a total carbohydrate content of 10.7%, comprising 6.0% neutral sugar, 3.67% glucosamine and 1.04% sialic acid. The iodoamino acid and amino acid composition of camel thyroglobulin is similar to that of other mammalian species.     

Soil mycoflora in tomato fields

Density and species richness of fungal communities in soils ofFusarium infested and non-infested tomato-growing localities were studied by comparison of rhizoplanes, rhizospheres, and root-free soils. The rhizosphere soils harbored the highest counts of fungi, followed by root-free soil and rhizoplanes in both localities. Species richness was high in the rhizosphere and root-free soil but distinctly low in the rhizoplane. The population density of the zhizosphere and the rhizoplane showed a significant difference between infested and non-infested localities.     

Searching for tagged male-sterile mutants of arabidopsis

Although many male-sterile mutants have been identified inArbidopsis thaliana, few of the corresponding genes have been cloned. In order to facilitate cloning of a male sterility gene, 23 of Feldmann's T-DNA-generated, reduced-fertility lines were screened to identify a tagged male-sterile mutation. Malesterile mutants were identified, as well as mutants that were both male and female sterile. Segregation of the kanamycin marker gene in the progeny of 15 of these lines was studied. Forty percent had functional T-DNAs (encoding resistance to kanamycin) inserted at a single locus, the remainder segregating for two or more functional T-DNA inserts. Linkage between T-DNA inserts and mutant phenotype was tested for six lines. In three of these lines, mutations were not linked to a T-DNA insert. In three lines, the mutation segregated with a T-DNA insert.     

Transgenic Murine Dopaminergic Neurons Expressing Human Cu/Zn Superoxide Dismutase Exhibit Increased Density in Culture, but No Resistance to Methylphenylpyridinium-Induced Degeneration

Abstract: Primary dopaminergic neuronal cultures with increased superoxide dismutase (SOD) activity were established for studying the role of superoxide anion (O₂^?) in 1-methyl-4-phenylpyridinium (MPP⁺)-induced degeneration of dopamine (DA) neurons. Mean SOD activity in cultures prepared from transgenic (human) Cu/Zn SOD (hSOD1) mice was 2.46–2.60 times greater than in cultures prepared from nontransgenic control mice. After 1 and 2 weeks in culture, the mean density of DA neurons [number of tyrosine hydroxylase-immunoreactive (TH-ir) cells per visual field] was significantly higher in cultures prepared from transgenic mice compared with those prepared from nontransgenic control mice (4.55–5.63 TH-ir neurons per field in hSOD1 cultures vs. 2.66–2.8 TH-ir neurons per field in control cultures). However, uptake of [³H]DA relative to uptake of [³H]GABA was only slightly greater in hSOD1 cultures than in normal cultures (14.1 nmol of DA/100 nmol of GABA vs. 12.1 nmol of DA/100 nmol of GABA). Resistance to MPP⁺ toxicity was not significantly different from that in normal cultures when based on density of surviving TH-ir cell bodies (EC₅₀ = 0.54 µM in hSOD1 and EC₅₀ = 0.37 µM in normal cultures). A more sensitive measure of DA neuron integrity and function ([³H]DA uptake) also failed to demonstrate increased resistance of hSOD1 cultures to the toxin (EC₅₀ = 73.7 nM in hSOD1 and EC₅₀ = 86.2 nM in controls). These results do not support the hypothesis that neurotoxicity of the active metabolite of MPTP, MPP⁺, is mediated by generation of O₂^? in the cytoplasm. Nevertheless, mesencephalic cultures with increased hSOD1 activity appear to survive better than normal control cultures in the oxidatively stressful environment of cell culture incubators, and such mesencephalic cells may be useful for cell grafting studies in animal models of Parkinson's disease.