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排序方式: 共有137条查询结果,搜索用时 15 毫秒
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42.
Tao W Lee MH Yoon MY Kim JC Malhotra S Wu J Hwang EC Lee SW 《Journal of microbiology and biotechnology》2011,21(12):1203-1210
Function-driven metagenomic analysis is a powerful approach to screening for novel biocatalysts. In this study, we investigated lipolytic enzymes selected from an alluvial soil metagenomic library, and identified two novel esterases, EstDL26 and EstDL136. EstDL26 and EstDL136 reactivated chloramphenicol from its acetyl derivates by counteracting the chloramphenicol acetyltransferase (CAT) activity in Escherichia coli. These two enzymes showed only 27% identity in amino acid sequence to each other; however both preferentially hydrolyzed short-chain p-nitrophenyl esters (< or =C5) and showed mesophilic properties. In vitro, EstDL136 catalyzed the deacetylation of 1- and 3- acetyl and 1,3-diacetyl derivates; in contrast, EstDL26 was not capable of the deacetylation at C1, indicating a potential regioselectivity. EstDL26 and EstDL136 were similar to microbial hormone-sensitive lipase (HSL), and since chloramphenicol acetate esterase (CAE) activity was detected from two other soil esterases in the HSL family, this suggests a distribution of CAE among the soil microorganisms. The isolation and characterization of EstDL26 and EstDL136 in this study may be helpful in understanding the diversity of CAE enzymes and their potential role in releasing active chloramphenicol in the producing bacteria. 相似文献
43.
Katja Hattar Rajkumar Savai Florentine S. B. Subtil Jochen Wilhelm Anja Schmall Dagmar S. Lang Torsten Goldmann Bastian Eul Gabriele Dahlem Ludger Fink Ralph-Theo Schermuly Gamal-Andre Banat Ulf Sibelius Friedrich Grimminger Ekkehard Vollmer Werner Seeger Ulrich Grandel 《Cancer immunology, immunotherapy : CII》2013,62(2):309-320
Lung cancer is frequently complicated by pulmonary infections which may impair prognosis of this disease. Therefore, we investigated the effect of bacterial lipopolysaccharides (LPS) on tumor proliferation in vitro in the non-small cell lung cancer (NSCLC) cell line A549, ex vivo in a tissue culture model using human NSCLC specimens and in vivo in the A549 adenocarcinoma mouse model. LPS induced a time- and dose-dependent increase in proliferation of A549 cells as quantified by MTS activity and cell counting. In parallel, an increased expression of the proliferation marker Ki-67 and cyclooxygenase (COX)-2 was detected both in A549 cells and in ex vivo human NSCLC tissue. Large amounts of COX-2-derived prostaglandin (PG)E2 were secreted from LPS-stimulated A549 cells. Pharmacological interventions revealed that the proliferative effect of LPS was dependent on CD14 and Toll-like receptor (TLR)4. Moreover, blocking of the epidermal growth factor receptor (EGFR) also decreased LPS-induced proliferation of A549 cells. Inhibition of COX-2 activity in A549 cells severely attenuated both PGE2 release and proliferation in response to LPS. Synthesis of PGE2 was also reduced by inhibiting CD14, TLR4 and EGFR in A549 cells. The proliferative effect of LPS on A549 cells could be reproduced in the A549 adenocarcinoma mouse model with enhancement of tumor growth and Ki-67 expression in implanted tumors. In summary, LPS induces proliferation of NSCLC cells in vitro, ex vivo in human NSCLC specimen and in vivo in a mouse model of NSCLC. Pulmonary infection may thus directly induce tumor progression in NSCLC. 相似文献
44.
Eulàlia Gassó Miracle M 《Journal of the history of biology》2011,44(3):445-481
By following the arguments between Coenraad J. Temminck and fellow ornithologists Louis J.-P. Vieillot and Nicholas Vigors,
this paper sketches, to a degree, the state of zoological classification and nomenclature between 1825 and 1840 in Europe.
The discussions revolved around the problems caused by an unstable nomenclature, the different definitions of genera and species
and the best method to achieve a natural system of classification. As more and more naturalists concerned with classifying
and arranging the groups of birds joined these discussions, a broad platform for debate emerged around the 1840s that gave
a major impulse to the disciplines of taxonomy and systematics. Natural history ceased to be dominated by a few influential
scientific authorities and became the scientific field where debate preceded agreement and, with it, progress. With this ‘democratization’
of natural history, Temminck’s status significantly changed between 1815 and 1840. After that year, his own views on classification
along with certain economical and political developments in The Netherlands led Temminck to abandon the arena of ornithology
and therefore, to lose his scientific authority. 相似文献
45.
Development of species‐specific primers for rapid diagnosis of Tetranychus urticae,T. kanzawai,T. phaselus and T. truncatus (Acari: Tetranychidae) 下载免费PDF全文
Jae‐Kyoung Shim Tin Moe Khaing Han‐Eul Seo Jun‐Yung Ahn Duck‐Oung Jung Jong‐Ho Lee Kyeong‐Yeoll Lee 《Entomological Research》2016,46(2):162-169
Species diagnosis is of the utmost importance to both pest management and plant quarantine services. Because of difficulties in the morphological diagnosis of spider mites, molecular techniques are of great value to rapidly and accurately diagnose closely related species. We examined four species of genus Tetranychus (the green and red forms of T. urticae, and T. kanzawai, T. phaselus and T. truncatus), which are found in Korea and are of significance to plant quarantine services. DNA samples isolated from a single egg, larva or adult weighed 64–188 ng. We designed species‐specific primers by performing sequence alignment for 107 sequences of the ribosomal internal transcribed spacer 2 (ITS2) region, which we obtained from GenBank, and sequences generated in this study. Specific nucleotides of each species were selected for designing primers specific for each species. Each species‐specific primer pair, when used to perform PCR analyses, detected only the species from which it originated. However, a T. urticae‐specific primer pair did not discriminate between the green and red forms of this species. These species‐specific primers can be applied in practice for the rapid and accurate diagnosis of spider mite species in plant quarantine and in agricultural fields. 相似文献
46.
José Mauro Granjeiro Carmen Verissima Ferreira Paulo Afonso Granjeiro Cinthia Celestino Da Silva Eulázio Mikio Taga Pedro Luiz Onofre Volpe 《Journal of enzyme inhibition and medicinal chemistry》2013,28(5):345-350
Uric acid inhibited 50% of the activity of bovine kidney low molecular mass phosphotyrosine protein phosphatase at concentrations of 1.0, 0.4, 1.3, and 0.2 mM, respectively for p -nitrophenyl phosphate (p -NPP), flavine mononucleotide, β -naphthyl phosphate and tyrosine phosphate (Tyr-P) as substrates. The mixed type inhibition of p -NPP hydrolysis was fully reversible, with K ic and K iu values of 0.4 and 1.1 mM, respectively; the inhibition by uric acid shifted the pH optimum from 5.0 to 6.5. When Tyr-P was the substrate, competitive inhibition was observed with a K i value of 0.05 mM. Inhibition studies by uric acid in the presence of thiol compounds, and preincubation studies in the presence of inorganic phosphate suggest that the interaction of uric acid with the enzyme occurred at the active site, but did not involve SH residues, and that the mechanism of inhibition depended on the structure of the substrates. 相似文献
47.
Impact on fatty acid metabolism and differential localization of FATP1 and FAT/CD36 proteins delivered in cultured human muscle cells 总被引:1,自引:0,他引:1
García-Martínez C Marotta M Moore-Carrasco R Guitart M Camps M Busquets S Montell E Gómez-Foix AM 《American journal of physiology. Cell physiology》2005,288(6):C1264-C1272
We compared the intracellular distribution and regulatory role of fatty acid transporter protein (FATP1) and fatty acid translocase (FAT/CD36) on muscle cell fatty acid metabolism. With the use of adenoviruses, FATP1 and FAT genes were delivered to primary cultured human muscle cells. FATP1 and FAT moderately enhanced palmitate and oleate transport evenly at concentrations of 0.05, 0.5, and 1 mM. Long-term (16 h) consumption of palmitate and oleate from the media, and particularly incorporation into triacylglyceride (TAG), was stimulated equivalently by FATP1 and FAT at all fatty acid concentrations tested. In contrast, long-term CO2 production was reduced by FATP1 and FAT at all doses of palmitate and at the lower concentrations of oleate. Neither FATP1 nor FAT markedly altered the production of acid-soluble metabolic intermediates from palmitate or oleate. The intracellular localization of fusion constructs of FATP1 and FAT with enhanced green fluorescent protein (EGFP) was examined. Independently of fatty acid treatment, FATPGFP was observed throughout the cytosol in a reticular pattern and concentrated in the perinuclear region, partly overlapping with the Golgi marker GM-130. FATGFP was found in the extracellular membrane and in cytosolic vesicles not coincident with GM-130. Neither FATP1 nor FAT proteins colocalized with lipid droplets in oleate-treated cells. We conclude that whereas FAT is localized on the extracellular membrane, FATP1 is active in the cytosol and imports fatty acids into myotubes. Overall, both FATP1 and FAT stimulated transport and consumption of palmitate and oleate, which they channeled away from complete oxidation and toward TAG synthesis. palmitate; oleate; fatty acid binding proteins; skeletal muscle 相似文献
48.
Alejandre-Alcázar MA Kwapiszewska G Reiss I Amarie OV Marsh LM Sevilla-Pérez J Wygrecka M Eul B Köbrich S Hesse M Schermuly RT Seeger W Eickelberg O Morty RE 《American journal of physiology. Lung cellular and molecular physiology》2007,292(2):L537-L549
Prematurely born infants who require oxygen therapy often develop bronchopulmonary dysplasia (BPD), a debilitating disorder characterized by pronounced alveolar hypoplasia. Hyperoxic injury is believed to disrupt critical signaling pathways that direct lung development, causing BPD. We investigated the effects of normobaric hyperoxia on transforming growth factor (TGF)-beta and bone morphogenetic protein (BMP) signaling in neonatal C57BL/6J mice exposed to 21% or 85% O(2) between postnatal days P1 and P28. Growth and respiratory compliance were significantly impaired in pups exposed to 85% O(2), and these pups also exhibited a pronounced arrest of alveolarization, accompanied by dysregulated expression and localization of both receptor (ALK-1, ALK-3, ALK-6, and the TGF-beta type II receptor) and Smad (Smads 1, 3, and 4) proteins. TGF-beta signaling was potentiated, whereas BMP signaling was impaired both in the lungs of pups exposed to 85% O(2) as well as in MLE-12 mouse lung epithelial cells and NIH/3T3 and primary lung fibroblasts cultured in 85% O(2). After exposure to 85% O(2), primary alveolar type II cells were more susceptible to TGF-beta-induced apoptosis, whereas primary pulmonary artery smooth muscle cells were unaffected. Exposure of primary lung fibroblasts to 85% O(2) significantly enhanced the TGF-beta-stimulated production of the alpha(1) subunit of type I collagen (Ialpha(1)), tissue inhibitor of metalloproteinase-1, tropoelastin, and tenascin-C. These data demonstrated that hyperoxia significantly affects TGF-beta/BMP signaling in the lung, including processes central to septation and, hence, alveolarization. The amenability of these pathways to genetic and pharmacological manipulation may provide alternative avenues for the management of BPD. 相似文献
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