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991.
Sumathy Babitha Dung H. Nguyen Sang-Joo Park Jeong-Hyun Shin Gaudelia A. Reyes Adeltrudes Caburian Eun-Ki Kim 《Biotechnology and Bioprocess Engineering》2010,15(6):1071-1076
In vitiligo, active melanocytes in the epidermis are not present, whereas melanoblast cells in the outer root sheath of hair
follicles are not affected. The existence of these inactive melanocytes provides a source for repigmentation of vitiligo.
To evaluate the potential of herbal candidates in treatment of vitiligo, we studied the effect of Cassia alata leaf extract on the differentiation, proliferation and migration of melanoblast cells. Melanin content increased in melb-a
melanoblast cells in response to this herb extract in a dose-dependent manner compared to control cells. In addition, it induced
tyrosinase activity and altered melb-a cell morphology. A transwell migration assay showed the potential of this herbal candidate
to induce direct migration of treated cells. To our knowledge, this is the first report on activity of this kind in Cassia alata. The findings of the present study are significant in the direction of developing safer strategies for vitiligo treatment. 相似文献
992.
The oxygen isotope composition (δ18O) of atmospheric CO2 is among a very limited number of tools available to constrain estimates of the biospheric gross CO2 fluxes, photosynthesis and respiration at large scales. However, the accuracy of the partitioning strongly depends on the extent of isotopic disequilibrium between the signals carried by these two gross fluxes. Chamber‐based field measurements of total CO2 and CO18O fluxes from foliage and soil can help evaluate and refine our models of isotopic fractionation by plants and soils and validate the extent and pattern of isotopic disequilibrium within terrestrial ecosystems. Owing to sampling limitations in the past, such measurements have been very rare and covered only a few days. In this study, we coupled automated branch and soil chambers with tuneable diode laser absorption spectroscopy techniques to continuously capture the δ18O signals of foliage and soil CO2 exchange in a Pinus pinaster Aït forest in France. Over the growing season, we observed a seasonally persistent isotopic disequilibrium between the δ18O signatures of net CO2 fluxes from leaves and soils, except during rain events when the isotopic imbalance became temporarily weaker. Variations in the δ18O of CO2 exchanged between leaves, soil and the atmosphere were well explained by theory describing changes in the oxygen isotope composition of ecosystem water pools in response to changes in leaf transpiration and soil evaporation. 相似文献
993.
Robert W. Huigens Samuel Reyes Catherine S. Reed Cynthia Bunders Steven A. Rogers Andrew T. Steinhauer Christian Melander 《Bioorganic & medicinal chemistry》2010,18(2):663-674
Multidrug-resistant bacterial infections continue to be a rising global health concern. Herein is described the development of a class of novel 2-aminobenzimidazoles with antibiotic activity. These active 2-aminobenzimidazoles retain their antibiotic activity against several strains of multidrug-resistant Staphylococcus aureus and Acinetobacter baumannii when compared to susceptible strains. 相似文献
994.
Aims: This study aims to investigate the ecology of coliphages, an important microbial pollution indicator. Specifically, our experiments address (i) the ability of environmental Escherichia coli (E. coli) to serve as hosts for coliphage replication, and (ii) the temporal and spatial distribution of coliphages in coastal waters. Methods and Results: Water samples from three locations in California’s Newport Bay watershed were tested for the presence of coliphages every 2 weeks for an entire year. A total of nine E. coli strains isolated from various sources served as hosts for coliphage detection. Coliphage occurrence was significantly different between freshwater, estuarine and coastal locations and correlated with water temperature, salinity and rainfall in the watershed. The coliphages isolated on the environmental hosts had a broad host‐range relative to the coliphages isolated on an E. coli strain from sewage and a US EPA recommended strain for coliphage detection. Conclusions: Coliphage occurrence was related to the temperature, rainfall and salinity within the bay. The adaptation to a broad host‐range may enable the proliferation of coliphages in the aquatic environment. Significance and Impact of the Study: Understanding the seasonal variation of phages is useful for establishing a background level of coliphage presence in coastal waters. The broad host‐range of coliphages isolated on the environmental E. coli host calls for investigation of coliphage replication in the aquatic environment. 相似文献
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998.
Monserrat Chairez Antonia Luna-Velasco Jim A. Field Xiumin Ju Reyes Sierra-Alvarez 《Biodegradation》2010,21(2):235-244
Bromate (BrO3
−) is a carcinogenic contaminant formed during ozonation of waters that contain trace amounts of bromide. Previous research
shows that bromate can be microbially reduced to bromide using organic (i.e. acetate, glucose, ethanol) and inorganic (H2) electron-donating substrates. In this study, the reduction of bromate by a mixed microbial culture was investigated using
elemental sulfur (S0) as an electron donor. In batch bioassays performed at 30°C, bromate (0.30 mM) was completely converted to bromide after
10 days and no accumulation of intermediates occurred. Bromate was also reduced in cultures supplemented with thiosulfate
and hydrogen sulfide as electron donor. Our results demonstrated that S0-disproportionating microorganisms were responsible for the reduction of bromate in cultures spiked with S0 through an indirect mechanism involving microbial formation of sulfide and subsequent abiotic reduction of bromate by the
biogenic sulfide. Confirmation of this mechanism is the fact that bromate was shown to undergo rapid chemical reduction by
sulfide (but not S0 or thiosulfate) in abiotic experiments. Bromate concentrations above 0.30 mM inhibited sulfide formation by S0-disproportionating bacteria, leading to a decrease in the rate of bromate reduction. The results suggest that biological
formation of sulfide from by S0 disproportionation could support the chemical removal of bromate without having to directly use sulfide as a reagent. 相似文献
999.
Vianey Marín‐Cevada Jesús Caballero‐Mellado Rocío Bustillos‐Cristales Jesús Muñoz‐Rojas Miguel A. Mascarúa‐Esparza Miguel Castañeda‐Lucio Lucía López‐Reyes Lourdes Martínez‐Aguilar Luis E. Fuentes‐Ramírez 《Journal of Phytopathology》2010,158(2):93-99
Pink disease is a major problem in the pineapple canning industry. Affected fruit acquire a brownish pigment after pasteurization and can contaminate non‐affected fruit before they are released to the consumer. In the last few years, Pantoea citrea has been described as the causative agent of pink disease. In this study, over 300 bacterial isolates from pineapple plants, growing in Mexican commercial fields, and from soil close to plant roots were recovered. Over 250 isolates showed a very high similarity in their phenotypic and genotypic traits with Tatumella ptyseos, a close relative of Pantoea. These isolates exhibited typical pathogenicity reactions in pineapple juice tests, pineapple slices and fruit. On this basis, molecular identification procedures for the Tatumella isolates associated with pink disease were implemented. In affected fruit populations around 106 CFU/g of fresh tissue were recovered. This is first time that T. ptyseos is demonstrated as a causal agent of pink disease. 相似文献
1000.
Yazmid Reyes‐Dominguez Jin Woo Bok Harald Berger E. Keats Shwab Asjad Basheer Andreas Gallmetzer Claudio Scazzocchio Nancy Keller Joseph Strauss 《Molecular microbiology》2010,76(6):1376-1386
Fungal secondary metabolites are important bioactive compounds but the conditions leading to expression of most of the putative secondary metabolism (SM) genes predicted by fungal genomics are unknown. Here we describe a novel mechanism involved in SM‐gene regulation based on the finding that, in Aspergillus nidulans, mutants lacking components involved in heterochromatin formation show de‐repression of genes involved in biosynthesis of sterigmatocystin (ST), penicillin and terrequinone A. During the active growth phase, the silent ST gene cluster is marked by histone H3 lysine 9 trimethylation and contains high levels of the heterochromatin protein‐1 (HepA). Upon growth arrest and activation of SM, HepA and trimethylated H3K9 levels decrease concomitantly with increasing levels of acetylated histone H3. SM‐specific chromatin modifications are restricted to genes located inside the ST cluster, and constitutive heterochromatic marks persist at loci immediately outside the cluster. LaeA, a global activator of SM clusters in fungi, counteracts the establishment of heterochromatic marks. Thus, one level of regulation of the A. nidulans ST cluster employs epigenetic control by H3K9 methylation and HepA binding to establish a repressive chromatin structure and LaeA is involved in reversal of this heterochromatic signature inside the cluster, but not in that of flanking genes. 相似文献