An efficient synthesis of highly functionalized novel chromeno[4,3-b]pyrroles and indolizino[6,7-b]indoles as potent antimicrobial and antioxidant agents

A facile and efficient synthesis of novel chromeno[4,3-b]pyrroles has been accomplished by intramolecular 1,3-dipolar cycloaddition which on subsequent Pictet-Spengler cyclisation in presence of p-toluenesulfonic acid yielded indolizino[6,7-b]indoles. The synthesized chromenopyrroles and indolizinoindoles were evaluated for their antimicrobial and antioxidant activities. Compounds 7b, 7e, 7a and 7d exhibited respectively, good antibacterial and antifungal activities against tested pathogens when compared to reference control.     

A set of baculovirus transfer vectors for screening of affinity tags and parallel expression strategies

We report a set of baculovirus transfer vectors for parallel expression of proteins in fusion with a panel of affinity tags including GST, protein A, thioredoxin, CBP, and FLAG. This suite includes vectors to generate recombinant baculovirus by homologous recombination in insect cells or using the Bac-to-Bac technology. An application of the vector suite approach to the vitamin D receptor (VDR), a protein mainly expressed as inclusion bodies in Escherichia coli, is presented. We found that expression in fusion with GST and protein A provided an efficient compromise of excellent purification with acceptable yields and costs.     

Synthesis, dihydrofolate reductase inhibition, antitumor testing, and molecular modeling study of some new 4(3H)-quinazolinone analogs

In order to produce potent new leads for anticancer drugs, a new series of quinazoline analogs was designed to resemble methotrexate (MTX, 1) structure features and fitted with functional groups believed to enhance inhibition of mammalian DHFR activity. Molecular modeling studies were used to assess the fit of these compounds within the active site of human DHFR. The synthesized compounds were evaluated for their ability to inhibit mammalian DHFR in vitro and for their antitumor activity in a standard in vitro tissue culture assay panel. Compounds 28, 30, and 31 were the most active DHFR inhibitors with IC₅₀ values of 0.5, 0.4, and 0.4 μM, respectively. The most active antitumor agents in this study were compounds 19, 31, 41, and 47 with median growth inhibitory concentrations (GI₅₀) of 20.1, 23.5, 26.7, and 9.1 μM, respectively. Of this series of compounds, only compound 31 combined antitumor potency with potent DHFR inhibition; the other active antitumor compounds (19, 41, and 47) all had DHFR IC₅₀ values above 15 μM, suggesting that they might exert their antitumor potency through some other mode of action. Alternatively, the compounds could differ significantly in uptake or concentration within mammalian cells.     

Non-classical antifolates. Part 2: Synthesis,biological evaluation,and molecular modeling study of some new 2,6-substituted-quinazolin-4-ones

A new series of 2,6-substituted-quinazolin-4-ones was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 22, 33–37, 39–43, and 45 proved to be active DHFR inhibitors with IC₅₀ range of 0.4–1.0 μM. Compound 18 showed broad-spectrum antimicrobial activity comparable to the known antibiotic gentamicin. Compounds 34 and 36 showed antitumor activity at GI₅₀ (MG-MID) concentrations of 11.2, and 24.2 μM, respectively. Molecular modeling study including flexible alignment; electrostatic, hydrophobic mappings; and pharmacophore prediction were performed. A main featured pharmacophore model was developed which justifies the importance of the main pharmacophoric groups as well as of their relative distances. The substitution pattern and spatial considerations of the π-systems in regard to the quinazoline nucleus proved critical for biological activity.     

Differential Responses of Epiphytic and Planktonic Toxic Cyanobacteria to Allelopathic Substances of the Submerged Macrophyte Stratiotes aloides

The present study investigates the allelopathic effects of Stratiotes aloides on the growth and antioxidative biomarkers of epiphytic and planktonic toxic cyanobacteria in a batch experiment over a 15‐day exposure to different concentrations of aqueous acetone extract of this macrophyte. The results showed that epiphytic and planktonic species of cyanobacteria showed differential responses to the allelopathic activity of this macrophyte. S. aloides extract reduced the growth, alkaline phosphatase activity (APA) and toxin production of the planktonic cyanobacterium, Anabaena variabilis, with an increase in lipid peroxidation, glutathione and activities of antioxidative enzymes of this cyanobacterium. Conversely, this extract did not affect the growth and increased the toxin production in epiphytic cyanobacteria, with no significant effect on lipid peroixdation or the activities of APA and antioxidative enzymes of these species. This study is the first to suggest that the macrophyte S. aloides supports the growth and toxin production of its epiphytic cyanobacteria. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Decay Kinetics of an Interferon Gamma Release Assay with Anti-Tuberculosis Therapy in Newly Diagnosed Tuberculosis Cases

Background

Qualitative and quantitative changes in IGRA response offer promise as biomarkers to monitor Tuberculosis (TB) drug therapy, and for the comparison of new interventions. We studied the decay kinetics of TB-specific antigen T-cell responses measured with an in-house ELISPOT assay during the course of therapy.

Methods

Newly diagnosed sputum smear positive TB cases with typical TB chest radiographs were recruited. All patients were given standard anti-TB treatment. Each subject was followed up for 6 months and treatment outcomes were documented. Blood samples were obtained for the ESAT-6 and CFP-10 (EC) ELISPOT at diagnosis, 1-, 2-, 4- and 6-months. Qualitative and quantitative reversion of the ELISPOT results were assessed with McNemar test, conditional logistic regression and mixed-effects hierarchical Poisson models.

Results

A total of 116 cases were recruited and EC ELISPOT was positive for 87% (95 of 109) at recruitment. There was a significant decrease in the proportion of EC ELISPOT positive cases over the treatment period (p<0.001). Most of the reversion occurred between the start and first month of treatment and at completion at 6 months. ESAT-6 had higher median counts compared to CFP-10 at all time points. Counts for each antigen declined significantly with therapy (p<0.001). Reverters had lower median SFUs at the start of treatment compared to non-Reverters for both antigens. Apart from the higher median counts for non-Reverters, no other risk factors for non-reversion were found.

Conclusions

TB treatment induces qualitative and quantitative reversion of a positive in-house IGRA in newly diagnosed cases of active TB disease. As this does not occur reliably in the majority of cured individuals, qualitative and quantitative reversion of an IGRA ELISPOT has limited clinical utility as a surrogate marker of treatment efficacy.     

Purification and some properties of camel carboxypeptidase B

A carboxypeptidase B-like enzyme was purified 116-fold with a recovery of activity of 29% from a crude extract of camel pancreas by a four-step procedure consisting of two anion exchange chromatographies in succession, gel filtration and hydrophobic interaction chromatography. The enzyme was homogeneous on SDS and non-denaturing gel electrophoresis and on gel isoelectric focusing. Its molecular mass was found to be 31.5 kDa and its isoelectric point was estimated as 6.1. It was active towards a number of substrates that are cleaved by carboxypeptidases B from other species and was also susceptible to inhibition by inhibitors of such enzymes. The camel enzyme showed a pH optimum of 8.0 and it was seen to be a relatively potent kinase in vitro. The enzyme purified in this study was very similar to carboxypeptidases B isolated from other species in size, charge, substrate specificity and susceptibility to inhibition and thus it can be identified as camel carboxypeptidase B.     

Effect of aqueous leaf extract of Irvingia gabonensis on gastrointestinal tract in rodents

Effect of the aqueous leaf extract of I. gabonensis on the gastrointestinal tract was investigated on isolated rabbit jejunum, guinea pig ileum, gastrointestinal motility, castor oil-induced diarrhoea in mice and castor oil-induced fluid accumulation in rats. The results showed that the extract exhibited a concentration-dependent relaxation of spontaneous pendular movement of isolated rabbit jejunum and guinea pig ileum, and attenuated both acetylcholine-induced contraction of rabbit jejunum and histamine-induced contraction of guinea pig ileum. The extract (100, 200 and 400 mg/kg) also caused a significant dose-dependent decrease of gastrointestinal motility in mice (40.12, 39.45 and 37.45%), intestinal fluid accumulation in rats (71.43, 81.63 and 83.27%), and remarkably protected mice against castor oil-induced diarrhoea [58.33, 75 and 91.67% (Di Carlo score)] respectively. Preliminary phytochemical screening of the aqueous leaf extract of I. gabonensis revealed the presence of saponins, tannins, phenols and phlobatanins.     

Apigenin protects from hepatorenal damage caused by lead acetate in rats

Exposure to lead (Pb) is associated with serious health problems including hepatorenal toxicity. Apigenin is a natural-sourced flavonoid with promising antioxidant and anti-inflammatory effects. In this research, we investigated the potential protective role of apigenin against lead acetate (PbAc)-induced hepatorenal damage. Thus, this experiment studied the exposure of male Wistar Albino rats to apigenin and/or PbAc and their effects in comparison to the control rats. Apigenin administration decreased the levels of Pb and prevented the histopathological deformations in liver and kidney tissues following PbAc exposure. This was confirmed by the normalized levels of liver and kidney function markers. Additionally, apigenin inhibited significantly oxidative reactions through upregulating Nrf2 and HO-1, and activating their downstreamed antioxidants accompanied by a marked depletion of pro-oxidants. Moreover, apigenin decreased the elevated pro-inflammatory cytokines and inhibited cell loss in liver and kidney tissues in response to PbAc intoxication in both tissues. The obtained results demonstrated that apigenin could be used to attenuate the molecular, biochemical, and histological alterations associated with Pb exposure due to its potent antioxidant, anti-inflammatory, and antiapoptotic effects.     

Sedimentary facies analysis of the subsurface triassic and hydrocarbon potential in the United Arab Emirates

Summary The Triassic sediments in the subsurface of the United Arab Emirates has been divided into three formations (from bottom to top): Sudair, Jilh (Gulailah) and Minjur. The Sudair Formation consists of four lithofacies units composed mainly of limestones and minor dolomites interbedded with terrigenous shaley mudstones and anhydritic dolomitic limestones. These were deposited in shallow marine supratidal to subtidal settings. The Jilh (Gulailah) Formation has five lithofacies units dominated by anhydritic dolomitic limestone, fine terrigenoclastic sediments and bioclastic and intraclastic limestones. The formation was laid down under lagoonal to supratidal sabkha conditions with little normal marine influence. The Minjur Formation is composed of three lithofacies units characterized by argillaceous quartzitic sandstones, shales, mudstones, dolomitic and ferruginous limestones with thin coal seams. These facies represent deposition in prograding delta lobes, reflecting humid continental to marginal-marine conditions. Diagenesis plays a major role in the reservoir development in the Triassic sediments, the pores are occluded by dolomite and anhydrite. The grains are compacted, leached or cemented by marine cements. Porosity generally ranges from fair to poor with values from 6% to 9% in the carbonates and from 6% to 15% in the clastics. Interparticle and vuggy porosities are the main pore types. The porosity was controlled by diagenesis, depth of burial and lithology. No oil has been discovered so far in the Triassic sediments of the United Arab Emirates but pronounced gas shows have been reported from offshore fields. Western offshore United Arab Emirates is a promising area for potential hydrocarbon accumulations. The Triassic sediments have low to moderate source rock potential; the organic matter is mainly sapropelic kerogen, and the degree of thermal alteration ranges between mature to highly mature stages.