Pyranocoumarins: A new class of anti-hyperglycemic and anti-dyslipidemic agents

A series of pyranocoumarin derivatives were synthesized and evaluated in vivo for their anti-hyperglycemic as well as anti-dyslipidemic activities. Compounds 7a, 7c, 8a, 8b, 8c, 8e and 8f have shown promising anti-hyperglycemic activities in sucrose loaded model (SLM) as well as sucrose challenged streptozotocin induced diabetic rat model (STZ). Compounds 8a and 8b were showing 38.0% and 42.0% blood glucose lowering activity in db/db mice model. In vitro anti-hyperglycemic activity evaluation exhibited that compounds 8a (IC₅₀ = 24.5 μM) and 8b (IC₅₀ = 36.2 μM) are potential PTP-1B inhibitors thereby revealing their possible mechanism of anti-diabetic action. Compounds 7a, 7b, 8a, 8b, 8d, 8e and 8f have shown significant anti-dyslipidemic activity in triton induced dyslipidemia in rats.     

Sensitive high performance liquid chromatographic assay for assessment of doxorubicin pharmacokinetics in mouse plasma and tissues

A sensitive high performance liquid chromatography method (HPLC) has been developed for the quantification of doxorubicin in mouse plasma and tissues. Samples of serum or tissue homogenates, 20 μl, were analyzed following a single step protein precipitation using perchloric acid (35%, v/v). Doxorubicin was separated from the internal standard, daunorubicin, on a Zorbax 300SB C₁₈ column at 35 °C. Mobile phase was comprised of acetonitrile and water (25:75) containing 0.1% triethylamine, and was adjusted to pH 3 with phosphoric acid. Peaks eluting from the column were detected with a fluorescence detector with excitation and emission wavelengths of 480 and 560 nm, respectively. Standard curves were linear in the range 5–1000 ng/ml, and correlation coefficients were typically greater than 0.999. Intra-assay recoveries ranged from 94.7 to 99.9%, and inter-assay recoveries were in the range of 95.2–101%. The associated coefficient of variation (CV) was less than 10% in all cases. The method was successfully applied to investigate doxorubicin plasma pharmacokinetics and tissue distribution in athymic Fox^nu mice.     

Large-scale separation of clavine alkaloids from Ipomoea muricata by pH-zone-refining centrifugal partition chromatography

Centrifugal partition chromatography in the pH-zone-refining mode was successfully applied to the separation of alkaloids, directly from a crude extract of Ipomoea muricata. The experiment was performed with a two-phase solvent system composed of methyl tert-butyl ether (MtBE)–acetonitrile–water (4:1:5, v/v) where triethylamine (10 mM) was added to the upper organic stationary phase as a retainer and trifluoroacetic acid (10 mM) to the aqueous mobile phase as an eluter. From 4 g of crude extract, 210 mg lysergol and 182 mg chanoclavine were obtained in 97% and 79.6% purities. Total yield recovery was >95%. Isolated alkaloids were characterized on the basis of their ¹H, ¹³C NMR and ESI-MS data.     

Ancestry-related assortative mating in Latino populations

Background

While spouse correlations have been documented for numerous traits, no prior studies have assessed assortative mating for genetic ancestry in admixed populations.

Results

Using 104 ancestry informative markers, we examined spouse correlations in genetic ancestry for Mexican spouse pairs recruited from Mexico City and the San Francisco Bay Area, and Puerto Rican spouse pairs recruited from Puerto Rico and New York City. In the Mexican pairs, we found strong spouse correlations for European and Native American ancestry, but no correlation in African ancestry. In the Puerto Rican pairs, we found significant spouse correlations for African ancestry and European ancestry but not Native American ancestry. Correlations were not attributable to variation in socioeconomic status or geographic heterogeneity. Past evidence of spouse correlation was also seen in the strong evidence of linkage disequilibrium between unlinked markers, which was accounted for in regression analysis by ancestral allele frequency difference at the pair of markers (European versus Native American for Mexicans, European versus African for Puerto Ricans). We also observed an excess of homozygosity at individual markers within the spouses, but this provided weaker evidence, as expected, of spouse correlation. Ancestry variance is predicted to decline in each generation, but less so under assortative mating. We used the current observed variances of ancestry to infer even stronger patterns of spouse ancestry correlation in previous generations.

Conclusions

Assortative mating related to genetic ancestry persists in Latino populations to the current day, and has impacted on the genomic structure in these populations.     

Co-localization of putative calcium channels (phenylalkylamine-binding sites) on oil bodies in protoplasts from dark-grown sunflower seedling cotyledons

Oil bodies are spherical entities containing a triacylglycerol (TAG) matrix encased by a phospholipid monolayer, which is stabilized by oil body-specific proteins, principally oleosins. Biochemical investigations in the recent past have also demonstrated the expression of calcium-binding proteins, called caleosins, as a component of oil body membranes during seed germination. Using DM-Bodipy-phenylalkylamine (PAA; a fluorescent derivative of phenylalkylamine)-a fluorescent probe known to bind L-type calcium channel proteins, present investigations provide the first report on the localization and preferential accumulation of putative calcium channel proteins on/around oil bodies during peak lipolytic phase in protoplasts derived from dark-grown sunflower (Helianthus annuus L. cv Morden) seedling cotyledons. Specificity of DM-Bodipy-PAA labeling was confirmed by using bepridil, a non-fluorescent competitor of PAA while non-specific dye accumulation has been ruled out by using Bodipy-FL as control. Co-localization of fluorescence from DM-Bodipy-PAA binding sites (ex: 504 nm; em: 511 nm) and nile red fluorescing oil bodies (ex: 552 nm; em: 636 nm) has been undertaken by epifluorescence and confocal laser scanning microscopy (CLSM). It revealed the affinity of PAA-sensitive ion channels for the oil body surface. Findings from the current investigations highlight the significance of calcium and calcium channel proteins during oil body mobilization in sunflower.Key words: calcium channels, confocal laser scanning microscopy, epifluorescence microscopy, oil bodies, phenylalkylamine-binding ion channels, seed germination, sunflower     

Design, synthesis, and biological evaluation of 1,2,3-trisubstituted-1,4-dihydrobenzo[g]quinoxaline-5,10-diones and related compounds as antifungal and antibacterial agents

A series of (S)-N-(3-chloro-1,4-naphthoquinon-2-yl)-alpha-amino acid ethyl esters 3 and 1,2,3-trisubstituted-1,4-dihydrobenzo[g]quinoxaline-5,10-diones 6-23 were synthesized and evaluated for antifungal and antibacterial activities. The structure-activity relationship of these compounds was studied and the results show that the compounds 3a and 3b exhibited in vitro antifungal activity against Candida albicans, Cryptococcus neoformans, and Sporothrix schenckii whereas compounds 12 and 22 showed in vitro antibacterial activity against Klebsiella pneumoniae and Escherichia coli.     

A new synthetic protocol for labeled oligonucleotides, using a chemically cleavable universal linker

A two-step general method for labeling of synthetic oligonucleotides is described. The protocol employs a cleavable universal linker, 5'-O-(4,4'-dimethoxytrityl)-3'-O-benzoyl-2'-O-(2-cyanoethyl-N,N-diisopropyl)-uridine phosphoramidite, to effect coupling to polymer-bound oligonucleotide chains. Sequentially, coupling with commercially available phosphoramidite reagent of an appropriate label (Biotin, HEX etc.) in an automated DNA synthesizer is carried out. The labeled oligomers, obtained after cleavage and deprotection reactions, are analyzed on RP-HPLC. A distinctive feature of this protocol is the recovery of free oligomers from their labeled analogs under mild conditions. The oligomers obtained are comparable to the corresponding standard oligonucleotides (HPLC).     

Optimization of medium for lipase production by Acinetobacter haemolyticus from healthy human skin

A lipase producing Acinetobacter haemolyticus TA106 was isolated from healthy human skin of tribal population. The maximum activity of 55 U/ml was observed after medium optimization using the "one variable at a time" and the statistical approaches. The optimal composition of the medium was determined as (% w/v or v/v): tryptone--1, yeast extract--0.5, sodium chloride-1, olive oil-1, Tween-80 1, manganese sulphate--5 mM, sucrose--1, pH-7. It was found that maximum production occurred in late log phase, i.e., after 72 h and at 200 rpm. From factorial design and statistical analysis, it was found that pH, temperature, salt, inoculum density and aeration significantly affected the lipase production. It was also noted that inoculum density of 3% (v/v), sucrose (1% w/v) and manganese sulphate (5 mM) displayed maximum lipase activity of 55 U/ml by conventional as well as statistical method. Optimization studies also indicated the increase in specific activity from 0.2 U/mg to 6.7 U/mg.     

Biochemistry of Microbial Degradation of Hexachlorocyclohexane and Prospects for Bioremediation

Summary: Lindane, the γ-isomer of hexachlorocyclohexane (HCH), is a potent insecticide. Purified lindane or unpurified mixtures of this and α-, β-, and δ-isomers of HCH were widely used as commercial insecticides in the last half of the 20th century. Large dumps of unused HCH isomers now constitute a major hazard because of their long residence times in soil and high nontarget toxicities. The major pathway for the aerobic degradation of HCH isomers in soil is the Lin pathway, and variants of this pathway will degrade all four of the HCH isomers although only slowly. Sequence differences in the primary LinA and LinB enzymes in the pathway play a key role in determining their ability to degrade the different isomers. LinA is a dehydrochlorinase, but little is known of its biochemistry. LinB is a hydrolytic dechlorinase that has been heterologously expressed and crystallized, and there is some understanding of the sequence-structure-function relationships underlying its substrate specificity and kinetics, although there are also some significant anomalies. The kinetics of some LinB variants are reported to be slow even for their preferred isomers. It is important to develop a better understanding of the biochemistries of the LinA and LinB variants and to use that knowledge to build better variants, because field trials of some bioremediation strategies based on the Lin pathway have yielded promising results but would not yet achieve economic levels of remediation.