Characterization of n-Hexane sub-fraction of Bridelia micrantha (Berth) and its antimycobacterium activity

<p>Abstract</p> <p>Background</p> <p>Tuberculosis, caused by <it>Mycobacterium tuberculosis </it>(MTB), is the most notified disease in the world. Development of resistance to first line drugs by MTB is a public health concern. As a result, there is the search for new and novel sources of antimycobacterial drugs for example from medicinal plants. In this study we determined the <it>in vitro </it>antimycobacterial activity of <it>n</it>-Hexane sub-fraction from <it>Bridelia micrantha </it>(Berth) against MTB H₃₇Ra and a clinical isolate resistant to all five first-line antituberculosis drugs.</p> <p>Methods</p> <p>The antimycobacterial activity of the <it>n</it>-Hexane sub-fraction of ethyl acetate fractions from acetone extracts of <it>B. micrantha </it>barks was evaluated using the resazurin microplate assay against two MTB isolates. Bioassay-guided fractionation of the ethyl acetate fraction was performed using 100% <it>n</it>-Hexane and Chloroform/Methanol (99:1) as solvents in order of increasing polarity by column chromatography and Resazurin microtiter plate assay for susceptibility tests.</p> <p>Results</p> <p>The <it>n</it>-Hexane fraction showed 20% inhibition of MTB H₃₇Ra and almost 35% inhibition of an MTB isolate resistant to all first-line drugs at 10 μg/mL. GC/MS analysis of the fraction resulted in the identification of twenty-four constituents representing 60.5% of the fraction. Some of the 24 compounds detected included Benzene, 1.3-bis (3-phenoxyphenoxy (13.51%), 2-pinen-4-one (10.03%), N(b)-benzyl-14-(carboxymethyl) (6.35%) and the least detected compound was linalool (0.2%).</p> <p>Conclusions</p> <p>The results show that the <it>n-</it>Hexane fraction of <it>B. micrantha </it>has antimycobacterial activity.</p

Novel conditionally immortalized human proximal tubule cell line expressing functional influx and efflux transporters

Reabsorption of filtered solutes from the glomerular filtrate and excretion of waste products and xenobiotics are the main functions of the renal proximal tubular (PT) epithelium. A human PT cell line expressing a range of functional transporters would help to augment current knowledge in renal physiology and pharmacology. We have established and characterized a conditionally immortalized PT epithelial cell line (ciPTEC) obtained by transfecting and subcloning cells exfoliated in the urine of a healthy volunteer. The PT origin of this line has been confirmed morphologically and by the expression of aminopeptidase N, zona occludens 1, aquaporin 1, dipeptidyl peptidase IV and multidrug resistance protein 4 together with alkaline phosphatase activity. ciPTEC assembles in a tight monolayer with limited diffusion of inulin-fluorescein-isothiocyanate. Concentration and time-dependent reabsorption of albumin via endocytosis has been demonstrated, together with sodium-dependent phosphate uptake. The expression and activity of apical efflux transporter p-glycoprotein and of baso-lateral influx transporter organic cation transporter 2 have been shown in ciPTEC. This established human ciPTEC expressing multiple endogenous organic ion transporters mimicking renal reabsorption and excretion represents a powerful tool for future in vitro transport studies in pharmacology and physiology

Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

<p>Abstract</p> <p>Background</p> <p>Use of essential oils for controlling <it>Candida albicans </it>growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against <it>Candida albicans </it>in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil.</p> <p>Methods</p> <p>Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of <it>C. albicans </it>cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated <it>C. albicans </it>cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS.</p> <p>Results</p> <p>Lemon grass (<it>Cymbopogon citratus</it>) essential oil exhibited the strongest antifungal effect followed by mentha (<it>Mentha piperita</it>) and eucalyptus (<it>Eucalyptus globulus</it>) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of <it>C. albicans </it>cells. SEM/AFM of <it>C. albicans </it>cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%).</p> <p>Conclusion</p> <p>Lemon grass essential oil is highly effective in vapour phase against <it>C. albicans</it>, leading to deleterious morphological changes in cellular structures and cell surface alterations.</p

Comparative Phylogeography in a Specific and Obligate Pollination Antagonism

In specific and obligate interactions the nature and abundance of a given species can have important effects on the survival and population dynamics of associated organisms. In a phylogeographic framework, we therefore expect that the fates of organisms interacting specifically are also tightly interrelated. Here we investigate such a scenario by analyzing the genetic structures of species interacting in an obligate plant-insect pollination lure-and-trap antagonism, involving Arum maculatum (Araceae) and its specific psychodid (Diptera) visitors Psychoda phalaenoides and Psycha grisescens. Because the interaction is asymmetric (i.e., only the plant depends on the insect), we expect the genetic structure of the plant to be related with the historical pollinator availability, yielding incongruent phylogeographic patterns between the interacting organisms

Angiogenesis and chronic kidney disease

The number of patients requiring renal replacement therapy due to end-stage renal disease (ESRD) is increasing worldwide. The prevalence of chronic kidney disease (CKD), and the importance of CKD as a risk factor in development of ESRD and in complicating cardiovascular disease (CVD) have been confirmed. In recent years, the involvement of angiogenesis-related factors in the progression of CKD has been studied, and the potential therapeutic effects on CKD of modulating these factors have been identified. Vascular endothelial growth factor (VEGF)-A, a potent pro-angiogenic factor, is involved in the development of the kidney, in maintenance of the glomerular capillary structure and filtration barrier, and in the renal repair process after injury. VEGF-A is also involved in the development of early diabetic nephropathy, demonstrated by the therapeutic effects of anti-VEGF-A antibody. Angiopoietin (Ang)-1 induces the maturation of newly formed blood vessels, and the therapeutic effects of Ang-1 in diabetic nephropathy have been described. In experimental models of diabetic nephropathy, the therapeutic effects of angiogenesis inhibitors, including angiostatin, endostatin and tumstatin peptides, the isocoumarin NM-3, and vasohibin-1, have been reported

Resource heterogeneity and community structure: A case study in Heliconia imbricata Phytotelmata

Complex or non-additive differences in the distribution and abundance of arthropod species inhabiting the water-filled bracts of Heliconia imbricata can be created by simple manipulations of resource levels. The primary resources for these assemblages are the corollas of the flowers that accumulate in the bracts. Removing or adding corollas to individual bracts changes the pattern in the abundance of arthropod species within each bract such that bracts with different treatments ultimately differ in composition and numerical associations among species. These results suggest that direct and indirect resource-mediated factors can structure or significantly affect the distribution and abundance of species in these and perhaps other assemblages. Thus, in natural communities, if resources are heterogeneous among patches (such as among the bracts in this study) structure in a given patch may be a function of the resource level of that patch and can differ significantly from neighboring patches that provide different resource levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47788/1/442_2004_Article_BF00665591.pd

Germline selection shapes human mitochondrial DNA diversity.

Approximately 2.4% of the human mitochondrial DNA (mtDNA) genome exhibits common homoplasmic genetic variation. We analyzed 12,975 whole-genome sequences to show that 45.1% of individuals from 1526 mother-offspring pairs harbor a mixed population of mtDNA (heteroplasmy), but the propensity for maternal transmission differs across the mitochondrial genome. Over one generation, we observed selection both for and against variants in specific genomic regions; known variants were more likely to be transmitted than previously unknown variants. However, new heteroplasmies were more likely to match the nuclear genetic ancestry as opposed to the ancestry of the mitochondrial genome on which the mutations occurred, validating our findings in 40,325 individuals. Thus, human mtDNA at the population level is shaped by selective forces within the female germ line under nuclear genetic control, which ensures consistency between the two independent genetic lineages.NIHR, Wellcome Trust, MRC, Genomics Englan