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991.
Patterns of intestinal helminth infections among school-aged children have been assessed in Eko-ende and Ore, as part of an overall assessment of the public health impact of Erinle Dam Reservoir in Osun State, Nigeria. The investigation was carried out between January and May 2005 using the Kato Katz thick smear technique and simple questionnaire for information on the bio-data, knowledge, attitude and practice of individuals towards disease transmission and control. Ascaris lumbricoides, hookworm, Trichuris trichiura, Taenia spp., Strongyloides stercoralis and Schistosoma mansoni were recovered at an overall prevalence of 78.3% among 309 children examined. Ascaris lumbricoides, hookworm, T. trichiura and S. mansoni were the most common infections while S. stercoralis and Taenia spp. were found only among a few children. Infection patterns of the common diseases were age-specific with peaks in the 11-15 age bracket. Children not attending school were significantly (P < 0.05) more at risk of infection than those attending school. Multiple infections were pronounced with over 54% double infections and 6% four parasites or more infections. The need for urgent intervention to arrest the obviously serious public health situation attributable to Erinle Dam is emphasized.  相似文献   
992.
Calcium- and integrin-binding protein 1 (CIB1) has been shown to be involved in cell spreading and migration. The signaling events regulated by CIB1 during cell migration are poorly understood. Here we found that accumulation of CIB1 at the tip of the filopodia requires an intact cytoskeleton. Depletion of CIB1 using shRNA affects formation of FAK- and phosphotyrosine-rich focal adhesions without affecting stress fiber formation. Overexpression of CIB1 results in cell migration on fibronectin and Erk1/2 MAP kinase activation. CIB1-induced cell migration is dependent upon Erk1/2 activation, since it is inhibited by the MEK-specific inhibitor PD98059. Furthermore, CIB1-induced cell migration, as well as Erk1/2 activation, is dependent on PKC, Src family kinases as well as PI-3 kinase as it is inhibited by bisindolylmaleimide 1, PP2, and wortmannin, respectively, in a dose-dependent manner. Co-expression of dominant-negative Cdc42 completely abolished CIB1-induced cell migration. Additionally, co-expression of constitutively active, but not dominant negative PAK1, a CIB1 binding protein, inhibited CIB1-induced cell migration. These results suggest that CIB1 positively regulates cell migration and is necessary for the recruitment of FAK to the focal adhesions. Furthermore, CIB1-induced cell migration is dependent on MAP kinase signaling and its function is attenuated by PAK1.  相似文献   
993.
The mutant strain bald-2 is unique among "flagellaless" strains of Chlamydomonas reinhardtii isolated to date, in that it possesses a mutant basal body: it is only capable of forming a ring of nine singlet microtubules, 180 nm in diameter, instead of the usual triplet basal body which is 225 nm in diameter. This singlet basal body lacks structural stability and the ability to associate with striated fiber material but retains two critical properties of basal bodies, namely, information specifying the length to which it should elongate and the ability to induce, albeit rarely, a flagellar transition region, a short, singlet-containing axoneme, and a specialized tunnel in the cell wall through which flagella normally emerge. The mutation seems to be specific for B- and C-microtubule synthesis or assembly since all other cytoplasmic sets of microtubules appear normal in numbers, orientation, and stability.  相似文献   
994.
Cell communication by periodic cyclic-AMP pulses.   总被引:26,自引:0,他引:26  
At the surface of aggregating cells of the slime mould, Dictyostelium discoideum, two different sites interacting with extracellular cAMP are detectable: binding sites and cycl-nucleotide phosphodiesterase. Both sites are developmentally regulated. An adequate stimulus for the chemoreceptor system in D. discoideum is the change of cAMP concentration in time, rather than concentration per se: long-term binding of cAMP causes only short-term response. The system is, consequently, adapted to the recognition of pulses rather than to steady-state concentrations of cAMP. The ce,lls are, nevertheless, able to sense stationary spatial gradients and to respond to them by chemotactic orientation. The possibility is discussed that they do so by transforming spatial concentration changes into temporal ones, using extending pseudopods as sensors. The cAMP recognition system is part of a molecular network involved in the generation of spatio-temporal patterns of cellular activities. This system controls the periodic formation of chemotactic signals and their propagation from cell to cell. The phosphodiesterase limits the duration of the cAMP pulses and thus sharply separates the periods of signalling; the binding sites at the cell surface are supposed to be the chemoreceptors. The control of cellular activities via cAMP receptors can be studied with biochemical techniques with cell suspensions in which spatial inhomogeneities are suppressed by intense stirring, whereas the temporal aspect of the spatiotemporal pattern is preserved. Under these conditions it can be shown that the extracellular cAMP concentration changes periodically, and that the phase of the cellular oscillator can be shifted by external pulses of cAMP. It can also be shown that small cAMP pulses induce a high output of cAMP, which demonstrates signal amplification, a function necessary for a cellular relay system.  相似文献   
995.
996.
997.
Insomnia is an epidemic in the US. Neurofeedback (NFB) is a little used, psychophysiological treatment with demonstrated usefulness for treating insomnia. Our objective was to assess whether two distinct Z-Score NFB protocols, a modified sensorimotor (SMR) protocol and a sequential, quantitative EEG (sQEEG)-guided, individually designed (IND) protocol, would alleviate sleep and associated daytime dysfunctions of participants with insomnia. Both protocols used instantaneous Z scores to determine reward condition administered when awake. Twelve adults with insomnia, free of other mental and uncontrolled physical illnesses, were randomly assigned to the SMR or IND group. Eight completed this randomized, parallel group, single-blind study. Both groups received fifteen 20-min sessions of Z-Score NFB. Pre-post assessments included sQEEG, mental health, quality of life, and insomnia status. ANOVA yielded significant post-treatment improvement for the combined group on all primary insomnia scores: Insomnia Severity Index (ISI p < .005), Pittsburgh Sleep Quality Inventory (PSQI p < .0001), PSQI Sleep Efficiency (p < .007), and Quality of Life Inventory (p < .02). Binomial tests of baseline EEGs indicated a significant proportion of excessively high levels of Delta and Beta power (p < .001) which were lowered post-treatment (paired z-tests p < .001). Baseline EEGs showed excessive sleepiness and hyperarousal, which improved post-treatment. Both Z-Score NFB groups improved in sleep and daytime functioning. Post-treatment, all participants were normal sleepers. Because there were no significant differences in the findings between the two groups, our future large scale studies will utilize the less burdensome to administer Z-Score SMR protocol.  相似文献   
998.
Three thermophilic strains of chemolithoautotrophic Fe(III)-reducers were isolated from mixed sediment and water samples (JW/KA-1 and JW/KA-2(T): Calcite Spring, Yellowstone N.P., WY, USA; JW/JH-Fiji-2: Savusavu, Vanu Levu, Fiji). All were Gram stain positive rods (approximately 0.5 x 1.8 microm). Cells occurred singly or in V-shaped pairs, and they formed long chains in complex media. All utilized H(2) to reduce amorphous iron (III) oxide/hydroxide to magnetite at temperatures from 50 to 75 degrees C (opt. approximately 73 degrees C). Growth occurred within the pH(60C) range of 6.5-8.5 (opt. pH(60C) 7.1-7.3). Magnetite production by resting cells occurred at pH(60C) 5.5-10.3 (opt. 7.3). The iron (III) reduction rate was 1.3 mumol Fe(II) produced x h(-1) x ml(-1) in a culture with 3 x 10(7) cells, one of the highest rates reported. In the presence or absence of H(2), JW/KA-2(T) did not utilize CO. The G + C content of the genomic DNA of the type strain is 52.7 +/- 0.3 mol%. Strains JW/KA-1 and JW/KA-2(T) each contain two different 16S rRNA gene sequences. The 16S rRNA gene sequences from JW/KA-1, JW/KA-2(T), or JW/JH-Fiji-2 possessed >99% similarity to each other but also 99% similarity to the 16S rRNA gene sequence from the anaerobic, thermophilic, hydrogenogenic CO-oxidizing bacterium 'Carboxydothermus restrictus' R1. DNA-DNA hybridization between strain JW/KA-2(T) and strain R1(T) yielded 35% similarity. Physiological characteristics and the 16S rRNA gene sequence analysis indicated that the strains represent two novel species and are placed into the novel genus Thermolithobacter within the phylum 'Firmicutes'. In addition, the levels of 16S rRNA gene sequence similarity between the lineage containing the Thermolithobacter and well-established members of the three existing classes of the 'Firmicutes' is less than 85%. Therefore, Thermolithobacter is proposed to constitute the first genus within a novel class of the 'Firmicutes', Thermolithobacteria. The Fe(III)-reducing Thermolithobacter ferrireducens gen. nov., sp. nov. is designated as the type species with strain JW/KA-2(T) (ATCC 700985(T), DSM 13639(T)) as its type strain. Strain R1(T) is the type strain for the hydrogenogenic, CO-oxidizing Thermolithobacter carboxydivorans sp. nov. (DSM 7242(T), VKM 2359(T)).  相似文献   
999.
A special interest exists concerning lungfish because they may possess characteristics of the common ancestor of land vertebrates. However, little is known about their blood and inflammatory cells; thus the fine structure, cytochemistry and differential cell counts of coelomic exudate and blood leucocytes were studied in Lepidosiren paradoxa. Blood smear analyses revealed erythrocytes, lymphocytes, monocytes, polymorphonuclear agranulocytes, thrombocytes and three different granulocytes. Blood monocytes and lymphocytes had typical vertebrate morphology. Thrombocytes had large vacuoles filled with a myelin rich structure. The polymorphonuclear agranulocyte had a nucleus morphologically similar to the human neutrophil with no apparent granules. Types I and II granulocytes had eosinophilic granules. Type I granulocytes had round or elongated granules heterogeneous in size, while type II had granules with an electron dense core. Type III granulocyte had many basophilic granules. The order of frequency was: type I granulocyte, followed by lymphocyte, type II granulocyte, monocyte, polymorphonuclear agranulocyte and type III granulocyte. Peroxidase localized mainly at the periphery of the granules from type II granulocytes, while no peroxidase expression was detected in type I granulocytes. Alkaline phosphatase was localized in the granules of type II granulocyte and acid phosphatase cytochemistry also labelled a few vacuoles of polymorphonuclear agranulocyte. About 85% of the coelomic inflammatory exudate cell population was type II granulocyte, 10% polymorphonuclear agranulocyte and 5% macrophages as judged by the nucleus and granule morphology. These results indicate that this lungfish utilises type II granulocytes as its main inflammatory granulocytes and that the polymorphonuclear agranulocyte may also be involved in the inflammatory response. The other two granulocytes appear similar to the mammalian eosinophil and basophil. In summary, this lungfish appears to possess the typical inflammatory granulocytes of teleosts, however, further functional studies are necessary to better understand the polymorphonuclear agranulocyte.  相似文献   
1000.
The main steps in the biosynthesis of complex secondary metabolites such as the antibiotic kirromycin are catalyzed by modular polyketide synthases (PKS) and/or nonribosomal peptide synthetases (NRPS). During antibiotic assembly, the biosynthetic intermediates are attached to carrier protein domains of these megaenzymes via a phosphopantetheinyl arm. This functional group of the carrier proteins is attached post-translationally by a phosphopantetheinyl transferase (PPTase). No experimental evidence exists about how such an activation of the carrier proteins of the kirromycin PKS/NRPS is accomplished. Here we report on the characterization of the PPTase KirP, which is encoded by a gene located in the kirromycin biosynthetic gene cluster. An inactivation of the kirP gene resulted in a 90% decrease in kirromycin production, indicating a substantial role for KirP in the biosynthesis of the antibiotic. In enzymatic assays, KirP was able to activate both acyl carrier protein and petidyl carrier domains of the kirromycin PKS/NRPS. In addition to coenzyme A (CoA), which is the natural substrate of KirP, the enzyme was able to transfer acyl-phosphopantetheinyl groups to the apo forms of the carrier proteins. Thus, KirP is very flexible in terms of both CoA substrate and carrier protein specificity. Our results indicate that KirP is the main PPTases that activates the carrier proteins in kirromycin biosynthesis.  相似文献   
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