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771.
772.
Elisabetta Carata Clelia Peano Salvatore M Tredici Francesco Ferrari Adelfia Talà Giorgio Corti Silvio Bicciato Gianluca De Bellis Pietro Alifano 《Microbial cell factories》2009,8(1):18-15
Background
There is evidence from previous works that bacterial secondary metabolism may be stimulated by genetic manipulation of RNA polymerase (RNAP). In this study we have used rifampicin selection as a strategy to genetically improve the erythromycin producer Saccharopolyspora erythraea. 相似文献773.
Oomen RJ Benito B Sentenac H Rodríguez-Navarro A Talón M Véry AA Domingo C 《The Plant journal : for cell and molecular biology》2012,71(5):750-762
We have investigated OsHKT2;1 natural variation in a collection of 49 cultivars with different levels of salt tolerance and geographical origins. The effect of identified polymorphism on OsHKT2;1 activity was analysed through heterologous expression of variants in Xenopus oocytes. OsHKT2;1 appeared to be a highly conserved protein with only five possible amino acid substitutions that have no substantial effect on functional properties. Our study, however, also identified a new HKT isoform, No-OsHKT2;2/1 in Nona Bokra, a highly salt-tolerant cultivar. No-OsHKT2;2/1 probably originated from a deletion in chromosome 6, producing a chimeric gene. Its 5' region corresponds to that of OsHKT2;2, whose full-length sequence is not present in Nipponbare but has been identified in Pokkali, a salt-tolerant rice cultivar. Its 3' region corresponds to that of OsHKT2;1. No-OsHKT2;2/1 is essentially expressed in roots and displays a significant level of expression at high Na(+) concentrations, in contrast to OsHKT2;1. Expressed in Xenopus oocytes or in Saccharomyces cerevisiae, No-OsHKT2;2/1 exhibited a strong permeability to Na(+) and K(+) , even at high external Na(+) concentrations, like OsHKT2;2, and in contrast to OsHKT2;1. Our results suggest that No-OsHKT2;2/1 can contribute to Nona Bokra salt tolerance by enabling root K(+) uptake under saline conditions. 相似文献
774.
775.
Angela A. Wendel Tal M. LewinRosalind A. Coleman 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2009,1791(6):501-506
Four homologous isoforms of glycerol-3-phosphate acyltransferase (GPAT), each the product of a separate gene, catalyze the synthesis of lysophosphatidic acid from glycerol-3-phosphate and long-chain acyl-CoA. This step initiates the synthesis of all the glycerolipids and evidence from gain-of-function and loss-of-function studies in mice and in cell culture strongly suggests that each isoform contributes to the synthesis of triacylglycerol. Much work remains to fully delineate the regulation of each GPAT isoform and its individual role in triacylglycerol synthesis. 相似文献
776.
Kewen Han Kyu Hyun Kim Junhwan Kim Wonsuk Lee Jing Liu Xudong Fan Tal Carmon Gaurav Bahl 《Journal of visualized experiments : JoVE》2014,(87)
Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained. 相似文献
777.
Moshe Giladi Lirin Michaeli Lior Almagor Dana Bar-On Tal Buki Uri Ashery Daniel Khananshvili Joel A. Hirsch 《Journal of molecular biology》2013
DOC2B (double-C2 domain) protein is thought to be a high-affinity Ca2 + sensor for spontaneous and asynchronous neurotransmitter release. To elucidate the molecular features underlying its physiological role, we determined the crystal structures of its isolated C2A and C2B domains and examined their Ca2 +-binding properties. We further characterized the solution structure of the tandem domains (C2AB) using small-angle X-ray scattering. In parallel, we tested structure–function correlates with live cell imaging tools. We found that, despite striking structural similarity, C2B binds Ca2 + with considerably higher affinity than C2A. The C2AB solution structure is best modeled as two domains with a highly flexible orientation and no difference in the presence or absence of Ca2 +. In addition, kinetic studies of C2AB demonstrate that, in the presence of unilamellar vesicles, Ca2 + binding is stabilized, as reflected by the ~ 10-fold slower rate of Ca2 + dissociation than in the absence of vesicles. In cells, isolated C2B translocates to the plasma membrane (PM) with an EC50 of 400 nM while the C2A does not translocate at submicromolar Ca2 + concentrations, supporting the biochemical observations. Nevertheless, C2AB translocates to the PM with an ~ 2-fold lower EC50 and to a greater extent than C2B. Our results, together with previous studies, reveal that the C2B is the primary Ca2 + sensing unit in DOC2B, whereas C2A enhances the interaction of C2AB with the PM. 相似文献
778.
779.
Exposure of Escherichia coli MRE-600 ribosomes to acridine orange (AO) at low ionic strength (1mM Tris-acetate pH 7.4) results in quantitative binding of the dye. Under our experimental conditions about a few hundred dye molecules can be bound to any one of the 30, 50, or 70-S particles. AO causes the 30 and the 50-S subunits to form ribosomal aggregates of approximate sedimentation constants of 70 and 100-S. 相似文献
780.
Avoidance learning and pain sensitivity were studied in rats after chronic ethanol administration (1.1 to 1.7 g per kg b.w. in drinking water) at prenatal, adolescent and adult ages. The behavioural reactions were tested in adulthood by studying passive and active avoidance learning and the threshold of pain sensitivity to electric tail shock. Chronic ethanol consumption led to an impairment of avoidance learning and to hyperalgesia in each experimental series, although the alterations were greater in the prenatally treated groups. The experimental observations are discussed in the light of fetal alcohol syndrome. 相似文献