Synthesis and biological evaluation of trans 6-methoxy-1,1-dimethyl-2-phenyl-3-aryl-2,3-dihydro-1H-inden-4-yloxyalkylamine derivatives against drug susceptible,non-replicating M. tuberculosis H37Rv and clinical multidrug resistant strains

Synthesis of a library of novel trans 6-methoxy-1,1-dimethyl-2-phenyl-3-aryl-2,3-dihydro-1H-inden-4-yloxy alkyl amines and their antimycobacterial activity against drug sensitive and multidrug resistant strains of Mycobacterium tuberculosis have been reported. All the new compounds in the series exhibited MIC between 1.56 and 6.25 μg/ml. Two compounds 1i and 1j with low MIC and low cytotoxicity showed significant reduction in CFU in infected mouse macrophages at 1× MIC concentration. The compound 1i inhibited the growth of M. tuberculosis in mice at 100 mg/kg dose with 1.35 log₁₀ reduction of CFU in lungs tissue and was active against non-replicating Mycobacterium tuberculosis under anaerobic condition.     

Lipid peroxidation in plumbagin administered rats

Plumbagin was administered to rats at a concentration of 1,2,4,8 and 16 mg per kg body weight. After 24 h lipid peroxide levels were found to decrease in subcellular fractions of liver. Plumbagin inhibited ascorbate and nicotinafde adenine dinucleotide phosphate (reduced) dependent lipid peroxidation but was without any effect on cumene hydroperoxide dependent lipid peroxidation. Injection of 16 mg of plumbagin per kg body weight was found to decrease liver total reduced glutathione and also fcrosomal glucose-6-phosphatase. The results are discussed with reference to the anti- and prooxidant properties of plumbagin.     

Enhanced Phosphodiestric Breakdown of Phosphatidylinositol Bisphosphate After Experimental Brain Injury

Abstract: Regional levels of lactate and inositol 1,4,5-trisphosphate (IP₃), a cellular second messenger of the excitatory neurotransmitter system, were measured after lateral fluid percussion (FP) brain injury in rats. At 5 min postinjury, tissue lactate concentrations were significantly elevated in the cortices and hippocampi of both the ipsilateral and contralateral hemispheres. By 20 min postinjury, lactate concentrations were elevated only in the cortices and hippocampus of the ipsilateral hemisphere. Whereas the IP₃ concentrations were elevated in the hippocampi of the ipsilateral and contralateral hemisphere and in the cortex of ipsilateral hemisphere at 5 min postinjury, no elevation in these sites was found at 20 min postinjury. Histologic analysis revealed neuronal damage in the cortex and CA3 regions of hippocampus ipsilateral to the injury at 24 h postinjury. The present results suggest activation of the phosphoinositide signal transduction pathway at the onset of injury and of a possible requirement of early persistent metabolic dysfunction (>20 min) such as the lactate accumulation in the delayed neuronal damage.     

Degradation of (+/-)-synephrine by Arthrobacter synephrinum. Oxidation of 3,4-dihydroxyphenylacetate to 2-hydroxy-5-carboxymethyl-muconate semialdehyde.

1. Cell-free extracts of Arthrobacter synephrinum catalyse the oxidation of 3,4-dihydroxy-phenylacetate. 2. The product of oxidation was characterized as 2-hydroxy-5-carboxymethylmuconate semialdehyde from its chemical behaviour as well as from nuclear-magnetic-resonance spectra. 3. A 3,4-dihydroxyphenylacetate 2,3-dioxygenase (EC 1.13.11.15) was partially purified from A. synephrinum. 4. The enzyme had a Km of 25 micrometer towards its substrate and exhibited typical Michaelis-Menten kinetics. 5. The enzyme also catalysed the oxidation of 3,4-dihydroxymandelate and 3,4-dihydroxyphenylpropionate, at reaction rates of 0.5 and 0.04 respectively of that for 3,4-dihydroxyphenylacetate. 6. The enzyme was sensitive to treatment with thiol-specific reagents. 7. The molecular weight of the enzyme as determined by Sephadex G-200 chromatography was approx. 282000.     

A study of the preferred environment of amino acid residues in globular proteins

In the native folded conformation of a globular protein, amino acid residues distant along the polypeptide chain come together to form the compact structure. This spatial structure is such that most of the polar residues are on the surface and have contact with the solvent medium and the nonpolar residues buried in the interior which have contact with similar nonpolar side chains. This cooperativity and mutual interaction among the randomly aligned amino acid residues suggest that each type of residue may prefer to have a specific environment. To gain more insight into this aspect of residue-residue cooperativity, a detailed analysis of the preferred environment associated with each of the 20 different amino acid residues in a number of protein crystals has been carried out. The variation of nonpolar nature computed for different sizes of spheres shows that the spatial region between radii of 6 and 8 Å is more favored for hydrophobic interactions and indicates that the influence of each residue over the surrounding medium extends predominantly up to a distance of 8 Å. The analysis of the surrounding amino acid residues associated with each type of residue shows that there is a definite tendency for each type of residue to have association with specific residues. The variation in environment is found even within the polar group as well as in the nonpolar group of residues. The surrounding residues associated with isoleucine, leucine, and valine are purely nonpolar. Proline, a nonpolar residue, is often surrounded by polar residues. The surrounding nonpolar nature of the tryptophan and tyrosine residues implies that even a single polar atom in a nonpolar side chain is sufficient to reduce their hydrophobic environment. There exists a high degree of mutual residue-residue cooperativity between the pairs glutamic acid-lysine, methionine-arginine, asparagine-tryptophan, and glutamine-proline, and the mutual residue-residue noncooperativity is high for the pairs methionine-aspartic acid, cysteine-glutamic acid, histidine-glutamine, and leucine-asparagine. The formation of secondary and tertiary structures is discussed in terms of the preferred environment and mutual cooperativity among various types of amino acid residues.     

Evaluation of a serological test for tuberculosis.

The agglutination test of Nicholls was found to be ineffective in diagnosing active tuberculosis. A positive result (titre of 1/125 or more) was found in the serum of 74 (70%) out of 105 patients with newly diagnosed, smear-positive pulmonary tuberculosis; 61 (62%) out of 98 healthy family contacts; and 19 (63%) out of 30 patients with non-tuberculous conditions. These findings were not due to faulty technique since the results obtained at Hammersmith were similar to those obtained by Nicholls''s laboratory in the same serum samples. Twenty-seven of the tuberculous patients who had a negative result before treatment were retested two months after the start of chemotherapy but showed no evidence of a rising titre.     

Extracellular protease from the antarctic yeast Candida humicola.

The psychrotrophic, dimorphic yeast Candida humicola, isolated from Antarctic soil, secretes an acidic protease into the medium. The secretion of this protease by C. humicola was found to be dependent on the composition of the medium. In YPD or yeast nitrogen base medium containing either amino acids or ammonium sulfate as the nitrogen source, the activity of the protease in the medium was low (basal level). However, when yeast nitrogen base medium was depleted of amino acids or ammonium sulfate and supplemented with proteins, the activity of the enzyme increased. The secretion of the enzyme was greater during exponential growth at low temperatures than during growth at higher temperatures. The purified protease had a molecular mass of 36,000 Da and was inhibited by pepstatin, iodoacetamide, and sodium dodecyl sulfate. Despite the prevalent cold temperatures in Antarctica, this extracellular protease of the psychrotrophic yeast C. humicola was active at temperatures ranging from 0 to 45 degrees C, with an optimum activity at 37 degrees C.     

Detailed characterization of the mRNA mapping in the HindIII fragment K region of the herpes simplex virus type 1 genome.

We have isolated as recombinant DNA clones, in the plasmid pBR322, regions of the herpesvirus type 1 genome spanning the region between 0.53 and 0.6 on the prototypical arrangement. This 11,000-base-pair region corresponds to 10% of the large unique region and encodes five major and several minor mRNA species abundant at different times after infection, which range in length from 7 to 1 kilobase. In this report, we have used RNA transfer blots and S1 nuclease digestion of hybrids between viral DNA and polyribosomal RNA to precisely localize (+/- 0.1 kilobase) these mRNA's. Comparison of neutral and alkaline gels of S1 nuclease-digested hybrids indicates no internal introns in the coding sequences of these mRNA's, although noncontiguous leader sequences near (ca. 0.1 kilobase) the 5' ends of any or all mRNA's could not be excluded. The 5' ends of several late mRNA's that are encoded opposite DNA strands map very close to one another, and the 3' ends of a major late and a major early mRNA, which are partially colinear, terminate in the same region. In vitro translation of the viral mRNA's isolated by hybridization with DNA bound to cellulose and fractionation of mRNA species on denaturing agarose gels allowed us to assign specific polypeptide products to each of the mRNA's characterized. Among other results, it was demonstrated unequivocally that two major late mRNA's, which partially overlap, encode the same polypeptide.     

Oxidative stress triggered by aluminum in plant roots

Aluminum (Al) is a major growth-limiting factor for plants in acid soils. The primary site of Al accumulation and toxicity is the root meristem, and the inhibition of root elongation is the most sensitive response to Al. Al cannot catalyze redox reactions but triggers lipid peroxidation and reactive oxygen species (ROS) production in roots. Furthermore, Al causes respiration inhibition and ATP depletion. Comparative studies of Al toxicity in roots with that in cultured plant cells suggest that Al causes dysfunction and ROS production in mitochondria, and that ROS production, but not lipid peroxidation, seems to be a determining factor of root-elongation inhibition by Al.     

Simultaneous tissue profiling of eicosanoid and endocannabinoid lipid families in a rat model of osteoarthritis

We describe a novel LC method for the simultaneous and quantitative profiling of 43 oxylipins including eicosanoids, endocannabinoids, and structurally related bioactive lipids with modified acyl groups. The LC-MS/MS method uses switching at a defined time between negative and positive electrospray ionization modes to achieve optimal detection sensitivity for all the lipids. The validated method is linear over a range of 0.01–5 nmol/g (0.1–50 nmol/g for 2-arachidonoyl glycerol) with intra- and interday precision and accuracy between 1.38 and 26.76% and 85.22 and 114.3%, respectively. The method successfully quantified bioactive lipids in different tissue types in the rat, including spinal cord, dorsal root ganglia (DRGs), knee joint, brain, and plasma. Distinct regional differences in the pattern of lipid measured between tissue types were observed using principle component analysis. The method was applied to analyze tissue samples from an established preclinical rat model of osteoarthritis (OA) pain and showed that levels of 12-hydroxyeicosatetraenoic acid were significantly increased in the OA rat knee joint compared with controls, and that 15-hydroxyeicosatetraenoic acid was significantly increased in the DRGs in the model of OA compared with controls. The developed LC-MS/MS method has the potential to provide detailed pathway profiling in tissues and biofluids where the disruption of bioactive oxylipins may be involved in disease states.