337 research outputs found

    Chemical composition of essential oils of Eugenia caryophylla and Mentha sp cf Piperita and their in vitro antifungal activities on six human pathogenic fungi

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    Background: Many fungal infections are responsible for human skin damages, to control their negative action, some aromatic and medicinal plants are traditionally used by local population in Cameroon. The present study was carried out to determine the chemical composition of essential oils of Eugenia caryophylla and Mentha sp cf piperita and their antifungal activity on some human pathogenic fungi.Materials and methods: Essential oils from Eugenia caryophylla and Mentha sp cf piperita were extracted by steam distillation using Clevenger apparatus and the antifungal activity was evaluated on six human pathogenic fungal strains; two yeasts (Candida albicans 1 and Candida albicans 2) and four dermatophytes (Tricophyton rubrum 1, T. rubrum 2, T. violaceum, and T. soudanensis) using modified broth microdilution method M27-A3 and M38-A respectively.Results: The essential oils obtained yielded of 5.9 for Eugenia caryophylla and 0.2% Mentha sp cf piperita respectively. The chemical composition was assigned by GC and GC/SM and showed that E. caryophylla was mainly composed of eugenol (80.0 %), E-caryophyllene (8.3%), and eugenol acetate (6.7%) while Mentha sp cf piperita was characterized by piperitone (67.5 %), menthol (10.0 %) and ß-phellandrene (5.8%). The result showed that essential oil of E. caryophylla exhibit the highest antifungal activity with MICs and MFC of 0.25μL/mL and 0.125μL/mL for filamentous fungi and MIC of 0.5 μL/mL for both yeast strains while MFC value was 1 μL/mL for one yeast strain and not determined for the second. MFCs Mentha sp cf piperita essential oil showed a weak activity with a MIC of 2.5 μL/mL on Tricophyton strains while no activity was exhibited on Candida albicans strains.Conclusion: The results of this work can be used to confirm their traditional uses and can also be proposed as natural ingredients to some industries to treat superficial infections.Keys words: Essential oil, Eugenia caryophylla, Mentha sp cf piperita, antifungal activity, Human pathogenic strains, fungistatic and fungicide

    Cytokinetic astralogy

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    Division plane specification in animal cells has long been presumed to involve direct contact between microtubules of the anaphase mitotic spindle and the cell cortex. In this issue, von Dassow et al. (von Dassow et al. 2009. J. Cell. Biol. doi:10.1083/jcb.200907090) challenge this assumption by showing that spindle microtubules can effectively position the division plane at a distance from the cell cortex

    Spire, an Actin Nucleation Factor, Regulates Cell Division during Drosophila Heart Development

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    The Drosophila dorsal vessel is a beneficial model system for studying the regulation of early heart development. Spire (Spir), an actin-nucleation factor, regulates actin dynamics in many developmental processes, such as cell shape determination, intracellular transport, and locomotion. Through protein expression pattern analysis, we demonstrate that the absence of spir function affects cell division in Myocyte enhancer factor 2-, Tinman (Tin)-, Even-skipped- and Seven up (Svp)-positive heart cells. In addition, genetic interaction analysis shows that spir functionally interacts with Dorsocross, tin, and pannier to properly specify the cardiac fate. Furthermore, through visualization of double heterozygous embryos, we determines that spir cooperates with CycA for heart cell specification and division. Finally, when comparing the spir mutant phenotype with that of a CycA mutant, the results suggest that most Svp-positive progenitors in spir mutant embryos cannot undergo full cell division at cell cycle 15, and that Tin-positive progenitors are arrested at cell cycle 16 as double-nucleated cells. We conclude that Spir plays a crucial role in controlling dorsal vessel formation and has a function in cell division during heart tube morphogenesis

    Tuberculosis in people newly diagnosed with HIV at a large HIV care and treatment center in Northwest Cameroon: Burden, comparative screening and diagnostic yields, and patient outcomes

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    BackgroundDiagnosis of tuberculosis in people living with HIV is challenging due to non-specific clinical presentations and inadequately sensitive diagnostic tests. The WHO recommends screening using a clinical algorithm followed by rapid diagnosis using the Xpert MTB/RIF assay, and more information is needed to evaluate these recommendations in different settings.MethodsFrom August 2012 to September 2013, consecutive adults newly diagnosed with HIV in Bamenda, Cameroon, were screened for TB regardless of symptoms by smear microscopy and culture; the Xpert MTB/RIF assay was performed retrospectively. Time to treatment and patient outcomes were obtained from routine registers.ResultsAmong 1,149 people enrolled, 940 (82%) produced sputum for lab testing; of these, 68% were women, the median age was 35 years (IQR, 28-42 years), the median CD4 count was 291cells/μL (IQR, 116-496 cells/μL), and 86% had one or more of current cough, fever, night sweats, or weight loss. In total, 131 people (14%, 95% CI, 12-16%) had sputum culture-positive TB. The WHO symptom screening algorithm had a sensitivity of 92% (95%CI, 86-96%) and specificity of 15% (95%CI, 12-17%) in this population. Compared to TB culture, the sensitivity of direct smear microscopy was 25% (95% CI, 18-34%), and the sensitivity of Xpert was 68% (95% CI, 58-76); the sensitivity of both was higher for people reporting more symptoms. Only one of 69 people with smear-negative/culture-positive TB was started on TB treatment prior to culture positivity. Of 71 people with bacteriologically-confirmed TB and known outcome after 6 months, 13 (17%) had died, including 11 people with smear-negative TB and 6 people with both smear and Xpert-negative TB.ConclusionsUse of the most sensitive rapid diagnostic test available is critical in people newly diagnosed with HIV in this setting to maximize the detection of bacteriologically-confirmed TB. However, this intervention is not sufficient alone and should be combined with more comprehensive clinical diagnosis of TB to improve outcomes

    Mutation analysis of the Fanconi anaemia A gene in breast tumours with loss of heterozygosity at 16q24.3

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    The recently identified Fanconi anaemia A (FAA) gene is located on chromosomal band 16q24.3 within a region that has been frequently reported to show loss of heterozygosity (LOH) in breast cancer. FAA mutation analysis of 19 breast tumours with specific LOH at 16q24.3 was performed. Single-stranded conformational polymorphism (SSCP) analysis on cDNA and genomic DNA, and Southern blotting failed to identify any tumour-specific mutations. Five polymorphisms were identified, but frequencies of occurrence did not deviate from those in a normal control population. Therefore, the FAA gene is not the gene targeted by LOH at 16q24.3 in breast cancer. Another tumour suppressor gene in this chromosomal region remains to be identified. © 1999 Cancer Research Campaig

    Intracellular Spatial Localization Regulated by the Microtubule Network

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    The commonly recognized mechanisms for spatial regulation inside the cell are membrane-bounded compartmentalization and biochemical association with subcellular organelles. We use computational modeling to investigate another spatial regulation mechanism mediated by the microtubule network in the cell. Our results demonstrate that the mitotic spindle can impose strong sequestration and concentration effects on molecules with binding affinity for microtubules, especially dynein-directed cargoes. The model can recapitulate the essence of three experimental observations on distinct microtubule network morphologies: the sequestration of germ plasm components by the mitotic spindles in the Drosophila syncytial embryo, the asymmetric cell division initiated by the time delay in centrosome maturation in the Drosophila neuroblast, and the diffusional block between neighboring energids in the Drosophila syncytial embryo. Our model thus suggests that the cell cycle-dependent changes in the microtubule network are critical for achieving different spatial regulation effects. The microtubule network provides a spatially extensive docking platform for molecules and gives rise to a “structured cytoplasm”, in contrast to a free and fluid environment

    Fanconi anemia genes are highly expressed in primitive CD34(+ )hematopoietic cells

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    BACKGROUND: Fanconi anemia (FA) is a complex recessive genetic disease characterized by progressive bone marrow failure (BM) and a predisposition to cancer. We have previously shown using the Fancc mouse model that the progressive BM failure results from a hematopoietic stem cell defect suggesting that function of the FA genes may reside in primitive hematopoietic stem cells. METHODS: Since genes involved in stem cell differentiation and/or maintenance are usually regulated at the transcription level, we used a semiquantitative RT-PCR method to evaluate FA gene transcript levels in purified hematopoietic stem cells. RESULTS: We show that most FA genes are highly expressed in primitive CD34-positive and negative cells compared to lower levels in more differentiated cells. However, in CD34(- )stem cells the Fancc gene was found to be expressed at low levels while Fancg was undetectable in this population. Furthermore, Fancg expression is significantly decreased in Fancc -/- stem cells as compared to wild-type cells while the cancer susceptibility genes Brca1 and Fancd1/Brac2 are upregulated in Fancc-/- hematopoietic cells. CONCLUSIONS: These results suggest that FA genes are regulated at the mRNA level, that increased Fancc expression in LTS-CD34(+ )cells correlates with a role at the CD34(+ )differentiation stage and that lack of Fancc affects the expression of other FA gene, more specifically Fancg and Fancd1/Brca2, through an unknown mechanism

    Gene Circuit Analysis of the Terminal Gap Gene huckebein

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    The early embryo of Drosophila melanogaster provides a powerful model system to study the role of genes in pattern formation. The gap gene network constitutes the first zygotic regulatory tier in the hierarchy of the segmentation genes involved in specifying the position of body segments. Here, we use an integrative, systems-level approach to investigate the regulatory effect of the terminal gap gene huckebein (hkb) on gap gene expression. We present quantitative expression data for the Hkb protein, which enable us to include hkb in gap gene circuit models. Gap gene circuits are mathematical models of gene networks used as computational tools to extract regulatory information from spatial expression data. This is achieved by fitting the model to gap gene expression patterns, in order to obtain estimates for regulatory parameters which predict a specific network topology. We show how considering variability in the data combined with analysis of parameter determinability significantly improves the biological relevance and consistency of the approach. Our models are in agreement with earlier results, which they extend in two important respects: First, we show that Hkb is involved in the regulation of the posterior hunchback (hb) domain, but does not have any other essential function. Specifically, Hkb is required for the anterior shift in the posterior border of this domain, which is now reproduced correctly in our models. Second, gap gene circuits presented here are able to reproduce mutants of terminal gap genes, while previously published models were unable to reproduce any null mutants correctly. As a consequence, our models now capture the expression dynamics of all posterior gap genes and some variational properties of the system correctly. This is an important step towards a better, quantitative understanding of the developmental and evolutionary dynamics of the gap gene network
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