789 research outputs found
In Vitro Antioxidant Activity of Bark Extracts of Rhizophora mucronata
The present study was conducted to evaluate the antioxidant activity of medicinal plant Rhizophora mucronata (R. mucronata). Shade dried stem bark of R. mucronata was powdered and extracted with 95% ethanol and water by cold extraction method. The total phenolic and flavonoid contents of water and ethanol extract of air dried stem bark was estimated by using spectrometric method. Antioxidant activity of R. mucronata was determined by using different methods namely DPPH radical scavenging assay, ferric reducing assay, nitric oxide radical scavenging assay, superoxide radical scavenging assay and ABTS radical scavenging assay, and its IC50 values were found to be 110.85, 193.47, 109.06, 88.69 and 12.56 ìg/ml for aqueous extract and 59.63, 242.71, 103.21, 84.95 and 4.21 ìg/ml respectively. The extracts exhibited marked dose dependent in vitro antioxidant activity. Secondary metabolite isolation and characterization and in vivo evaluation of aqueous and ethanolic extracts were under progress
Efficacy of Preserving Sea Foods Using Marine Lactobacillus
Scombroid food poisoning is a food borne illness that results from eating spoiled (decayed) fish. Histamine is the causative agent of scombroid poisoning, a food borne chemical intoxication. Histamine is one of the main biogenic amines and it is heterocyclic and biologically active primary amine, formed post-mortem in the muscles of scombroid and non-scombroid fish. The present study was carried out to isolate histamine-producing bacteria from a local fish and to test antibacterial activity of mangrove isolates of Lactobacillus species against the histamine producing bacteria. Fresh tuna fish (Euthinus affinis) obtained from Parangipettai coast and they were divided in to three groups. One group of the fish samples were stored directly and another two group of the fish samples were dipped in cold distilled water containing bacteriocin of Lactobacillus sp. and partially purified bacteriocin (10 ml, 1% v/v) respectively. The fish samples, after treatment were stored at 5, 15, 20 and 25 0C for the period of 24, 48, 72 and 96 h, respectively. Histamine quantification was performed at an interval of 24 h for four days. According to the results obtained it was proved that mangrove isolates of Lactobacillus species having high antimicrobial activity against histamine-producing bacteria which is responsible for spoilage of sea foods
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Application of external fields to the development of aluminum-based nanocomposite and master alloys
Application ultrasonic cavitation and high-energy pulses (e.g. detonation) is a promising way of incorporating reinforcing and grain refining particles in composite and master alloys. This paper gives an overview of research performed recently on the development of new technological approaches and materials with the aim to introduce and distribute nanoparticles in the matrix of aluminum alloys. Both types of particles, introduced externally or formed insitu are discussed. External fields are used for making concentrated master alloys, e.g. Alalumina with subsequent introduction of such a master alloy into the melt with the aid of ultrasonic cavitation; or for direct production of nanocomposites. The examples of implementation include Al-based composites reinforced with nanodiamonds, nanoalumina and nanospinel. The efficiency is illustrated by structure and properties characterization. The research is done within a European program on the application of external fields in liquid metal processing Exomet (EC grant 280421).The authors acknowledge financial support from the Exomet Project (which is co-funded by the European Commission in the 7th Framework Programme (contract FP7-NMP3-LA-2012-280421), by the European Space Agency and by the individual partner organisations)
Refining transcriptional regulatory networks using network evolutionary models and gene histories
<p>Abstract</p> <p>Background</p> <p>Computational inference of transcriptional regulatory networks remains a challenging problem, in part due to the lack of strong network models. In this paper we present evolutionary approaches to improve the inference of regulatory networks for a family of organisms by developing an evolutionary model for these networks and taking advantage of established phylogenetic relationships among these organisms. In previous work, we used a simple evolutionary model and provided extensive simulation results showing that phylogenetic information, combined with such a model, could be used to gain significant improvements on the performance of current inference algorithms.</p> <p>Results</p> <p>In this paper, we extend the evolutionary model so as to take into account gene duplications and losses, which are viewed as major drivers in the evolution of regulatory networks. We show how to adapt our evolutionary approach to this new model and provide detailed simulation results, which show significant improvement on the reference network inference algorithms. Different evolutionary histories for gene duplications and losses are studied, showing that our adapted approach is feasible under a broad range of conditions. We also provide results on biological data (<it>cis</it>-regulatory modules for 12 species of <it>Drosophila</it>), confirming our simulation results.</p
How Ubiquitin Unfolds after Transfer into the Gas Phase
The structural evolution of ubiquitin after transfer into the gas phase was studied by electron capture dissociation. Site-specific fragment yields show that ubiquitin’s solution fold is overall unstable in the gas phase, but unfolding caused by loss of solvent is slowest in regions stabilized by salt bridges
Search for flavor-changing neutral currents and lepton-family-number violation in two-body D0 decays
Results of a search for the three neutral charm decays, D0 -> mu e, D0 -> mu
mu, and D0 -> e e, are presented. This study was based on data collected in
Experiment 789 at the Fermi National Accelerator Laboratory using 800 GeV/c
proton-Au and proton-Be interactions. No evidence is found for any of the
decays. Upper limits on the branching ratios, at the 90% confidence level, are
obtained.Comment: 28 pages, 18 figures. Submitted to Physical Review
Lower production of IL-17A and increased susceptibility to Mycobacterium bovis in mice coinfected with Strongyloides venezuelensis
The presence of intestinal helminths can down-regulate the immune response required to control mycobacterial infection. BALB/c mice infected with Mycobacterium bovis following an infection with the intestinal helminth Strongyloides venezuelensis showed reduced interleukin-17A production by lung cells and increased bacterial burden. Also, small granulomas and a high accumulation of cells expressing the inhibitory molecule CTLA-4 were observed in the lung. These data suggest that intestinal helminth infection could have a detrimental effect on the control of tuberculosis (TB) and render coinfected individuals more susceptible to the development of TB
The secreted triose phosphate isomerase of Brugia malayi is required to sustain microfilaria production in vivo
Human lymphatic filariasis is a major tropical disease transmitted through mosquito vectors which take up microfilarial larvae from the blood of infected subjects. Microfilariae are produced by long-lived adult parasites, which also release a suite of excretory-secretory products that have recently been subject to in-depth proteomic analysis. Surprisingly, the most abundant secreted protein of adult Brugia malayi is triose phosphate isomerase (TPI), a glycolytic enzyme usually associated with the cytosol. We now show that while TPI is a prominent target of the antibody response to infection, there is little antibody-mediated inhibition of catalytic activity by polyclonal sera. We generated a panel of twenty-three anti-TPI monoclonal antibodies and found only two were able to block TPI enzymatic activity. Immunisation of jirds with B. malayi TPI, or mice with the homologous protein from the rodent filaria Litomosoides sigmodontis, failed to induce neutralising antibodies or protective immunity. In contrast, passive transfer of neutralising monoclonal antibody to mice prior to implantation with adult B. malayi resulted in 60–70% reductions in microfilarial levels in vivo and both oocyte and microfilarial production by individual adult females. The loss of fecundity was accompanied by reduced IFNγ expression by CD4+ T cells and a higher proportion of macrophages at the site of infection. Thus, enzymatically active TPI plays an important role in the transmission cycle of B. malayi filarial parasites and is identified as a potential target for immunological and pharmacological intervention against filarial infections
Right ventricular peak systolic longitudinal strain is a sensitive marker for right ventricular deterioration in adult patients with tetralogy of Fallot
The aim of this study was to evaluate the feasibility of right ventricular (RV) longitudinal peak systolic strain (LPSS) assessment for the follow-up of adult patients with corrected tetralogy of Fallot (TOF). Adult patients (n = 18) with corrected TOF underwent echocardiography and CMR twice with a time interval of 4.2 ± 1.7 years. RV performance was derived from CMR, and included RV volumes and ejection fraction (EF). LPSS was calculated globally (GLPSS) and in the RV free wall (LPSS FW), with echocardiographic speckle-tracking strain-analysis. Baseline (G)LPSS values were compared between patients and healthy controls; the relation between (G)LPSS and CMR parameters was evaluated and the changes in (G)LPSS and CMR parameters during follow-up were compared. GLPSS and LPSS FW were significantly reduced in patients as compared to controls (−14.9 ± 0.7% vs. −21.6 ± 0.9% and −15.5 ± 0.9% vs. −22.7 ± 1.5%, P < 0.01). Moderate agreement between LPSS and CMR parameters was observed. RV EF remained unchanged during follow-up, whereas GLPSS and LPSS FW demonstrated a significant reduction. RVEF showed a 1% increase, whereas GLPSS decreased by 14%, and LPSS FW by 27%. RV LPSS is reduced in TOF patients as compared to controls; during follow-up RV EF remained unchanged whereas LPSS decreased suggesting that RV LPSS may be a sensitive marker to detect early deterioration in RV performance
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