19 research outputs found

    The Design of a Portable Municipal Waste Incinerator with Fuzzy Logic Based Support for Emission Estimation

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    A fuzzy logic interface system to estimate oxygen requirement for complete combustion as well as the level of pollution from incinerator gas flue in order to manage solid waste from domestic, institutional, medical and industrial sources was designed. The designed incinerator is double chambered operating with a maximum temperature of 760 °C in the lower chamber and 1000°C in the upper chamber. The insulating wall is made up of a refractory brick of 55mm in thickness having a 2mm thickness low carbon steel as the outer wall. Hydrogen Chloride (HCl) and Nitrous oxides (NO)x are the gases was used to demonstrate the Fuzzy Inference System (FIS) model. The FIS was built with five input variables (Food, PVC, Polythene, Paper and Textile) and three input variables with two membership functions. The FIS was developed to estimation the degree of possibility distribution of pollution that should be expected when a certain composition of waste is incinerated. The plots of composition of waste high in food against oxygen require for combustion gives a possibility distribution of about 0.9 which is high according to the fuzzy set definition while the plot of waste composition high in PVC against HCL shows linearity

    Effects of experimental Neisseria meningitis W135 infection on serotoninergic parameters in mice

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    This study investigated the effects of Neisseria menigitidis W135 infection via intraperitoneal route on plasma free tryptophan concentration, brain serotonin and 5-hydroxyindole acetic acid (5-HIAA) levels in albino mice fed normal and tryptophan-enriched diets. The kinetics of appearance of viable bacteria in the blood, brain and liver following infection were also investigated. The serotoninergic parameters were determined by colorimetric and HPLC methods while colony counts were measured by plate count technique. Compared to normal diet, the tryptophan-enriched diet resulted in significantly (

    Mammalian cell entry genes in Streptomyces may provide clues to the evolution of bacterial virulence

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    Understanding the evolution of virulence is key to appreciating the role specific loci play in pathogenicity. Streptomyces species are generally non-pathogenic soil saprophytes, yet within their genome we can find homologues of virulence loci. One example of this is the mammalian cell entry (mce) locus, which has been characterised in Mycobacterium tuberculosis. To investigate the role in Streptomyces we deleted the mce locus and studied its impact on cell survival, morphology and interaction with other soil organisms. Disruption of the mce cluster resulted in virulence towards amoebae (Acanthamoeba polyphaga) and reduced colonization of plant (Arabidopsis) models, indicating these genes may play an important role in Streptomyces survival in the environment. Our data suggest that loss of mce in Streptomyces spp. may have profound effects on survival in a competitive soil environment, and provides insight in to the evolution and selection of these genes as virulence factors in related pathogenic organisms

    The type VII secretion system of <i>Staphylococcus aureus</i> secretes a nuclease toxin that targets competitor bacteria

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    The type VII protein secretion system (T7SS) plays a critical role in the virulence of human pathogens including Mycobacterium tuberculosis and Staphylococcus aureus. Here we report that the S. aureus T7SS secretes a large nuclease toxin, EsaD. The toxic activity of EsaD is neutralised during its biosynthesis through complex formation with an antitoxin, EsaG, which binds to its C-terminal nuclease domain. The secretion of EsaD is dependent upon a further accessory protein, EsaE, that does not interact with the nuclease domain, but instead binds to the EsaD N-terminal region. EsaE has a dual cytoplasmic/membrane localization and membrane-bound EsaE interacts with the T7SS secretion ATPase, EssC, implicating EsaE in targeting the EsaDG complex to the secretion apparatus. EsaD and EsaE are co-secreted whereas EsaG is found only in the cytoplasm and may be stripped off during the secretion process. Strain variants of S. aureus that lack esaD encode at least two copies of EsaG-like proteins most likely to protect themselves from the toxic activity of EsaD secreted by esaD(+) strains. In support of this, a strain overproducing EsaD elicits significant growth inhibition against a sensitive strain. We conclude that T7SSs may play unexpected and key roles in bacterial competitiveness

    A transposon insertion single-gene knockout library and new ordered cosmid library for the model organism Streptomyces coelicolor A3(2)

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    A simple and high-throughput transposon mediated mutagenesis system employing in vitro shuttle transposon mutagenesis has been used to systematically mutagenise the Streptomyces coelicolor genome. To achieve the highest coverage, a new ordered cosmid library was also constructed. Individual cosmids from both the existing and new libraries were disrupted using the Tn5-based mini-transposon Tn5062. A total of 35,358 insertions were sequenced resulting in the disruption of 6,482 genes (83% of the predicted open reading frames). Complete information for both the newly generated cosmids as well as all the insertions has been uploaded onto a central database, StrepDB ( http://strepdb.streptomyces.org.uk/ ). All insertions, new cosmids and a range of transposon exchange cassettes are available for study of individual gene function
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