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61.
Goldberg SL Nanduri V Cino PM Patel R 《Journal of industrial microbiology & biotechnology》2000,25(6):305-309
A bacterium, Eubacterium rectale IIIH, which possessed arylsulfotransferase (ASST) activity was isolated from human feces. The ASST gene (astA) was cloned and the corresponding protein partially characterized. This gene shows only moderate homology to the previously
sequenced ASST genes of Klebsiella and Enterobacter, which are very closely related to each other. Journal of Industrial Microbiology & Biotechnology (2000) 25, 305–309.
Received 02 August 2000/ Accepted in revised form 19 November 2000 相似文献
62.
Recombinant human pigment epithelium-derived factor (PEDF): characterization of PEDF overexpressed and secreted by eukaryotic cells. 总被引:1,自引:0,他引:1
E. Stratikos E. Alberdi P. G. Gettins S. P. Becerra 《Protein science : a publication of the Protein Society》1996,5(12):2575-2582
Pigment epithelium-derived factor (PEDF) is a serpin found in the interphotoreceptor matrix of the eye, which, although not a proteinase inhibitor, possesses a number of important biological properties, including promotion of neurite outgrowth and differential expression in quiescent versus senescent states of certain cell types. The low amounts present in the eye, together with the impracticality of using the eye as a source for isolation of the human protein, make it important to establish a system for overexpression of the recombinant protein for biochemical and biological studies. We describe here the expression and secretion of full-length glycosylated human recombinant PEDF at high levels (> 20 micrograms/ mL) into the growth medium of baby hamster kidney cells and characterization of the purified rPEDF by circular dichroism and fluorescence spectroscopies and neurite outgrowth assay. By these assays, the recombinant protein behaves as expected for a correctly folded full-length human PEDF. The availability of milligram amounts of PEDF has permitted quantitation of its heparin binding properties and of the effect of reactive center cleavage on the stability of PEDF towards thermal and guanidine hydrochloride denaturation. 相似文献
63.
64.
Solute accumulation and decreased photosynthesis in leaves of potato plants expressing yeast-derived invertase either in the apoplast, vacuole or cytosol 总被引:11,自引:0,他引:11
Dirk Büssis Dieter Heineke Uwe Sonnewald Lothar Willmitzer Klaus Raschke Hans-Walter Heldt 《Planta》1997,202(1):126-136
Potato (Solanum tuberosum cv. Désirée) plants expressing yeast invertase directed either to the apoplast, vacuole or cytosol were biochemically and
physiologically characterised. All lines of transgenic plants showed similarities to plants growing under water stress. Transformants
were retarded in growth, and accumulated hexoses and amino acids, especially proline, to levels up to 40-fold higher than
those of the wild types. In all transformants rates of CO2 assimilation and leaf conductance were reduced. From the unchanged intercellular partial pressure of CO2 and apoplastic cis-abscisic acid (ABA) content of transformed leaves it was concluded that the reduced rate of CO2 assimilation was not caused by a limitation in the availability of CO2 for␣the ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco). In the transformants the amount of Rubisco protein was
not reduced, but both activation state and carboxylation efficiency of photosynthesis were lowered. In vacuolar and cytosolic
transformants this inhibition of Rubisco might be caused by a changed ratio of organic bound and inorganic phosphate, as indicated
by a doubling of phosphorylated intermediates. But in apoplastic transformants the pattern of phosphorylated intermediates
resembled that of leaves of water-stressed potato plants, although the cause of inhibition of photosynthesis was not identical.
Whereas in water-stressed plants increased contents of the phytohormone ABA are supposed to mediate the adaptation to water
stress, no contribution of ABA to reduction of photosynthesis could be detected in invertase transformants.
Received: 29 May 1996 / Accepted: 30 December 1996 相似文献
65.
66.
Summary. Fatty acid amide hydrolase (FAAH), a membrane-anchored enzyme responsible for the termination of endocannabinoid signalling,
is an attractive target for treating conditions such as pain and anxiety. Inhibitors of the enzyme, optimized using rodent
FAAH, are known but their pharmacology and medicinal chemistry properties on the human FAAH are missing. Therefore recombinant
human enzyme would represent a powerful tool to evaluate new drug candidates. However, the production of high amounts of enzyme
is hampered by the known refractiveness of FAAH to overexpression. Here, we report the successful overexpression of rat and
human FAAH as a fusion to the E. coli maltose-binding protein, retaining catalytic properties of native FAAH. Several known FAAH inhibitors were tested and differences
in their potencies toward the human and rat FAAH were found, underscoring the importance of using a human FAAH in the development
of inhibitors.
Authors’ address: Didier M. Lambert, Unité de Chimie pharmaceutique et de Radiopharmacie, Université catholique de Louvain,
Avenue E. Mounier 73.40, 1200 Bruxelles, Belgique 相似文献
67.
Earlier we have shown the role of glyoxalase overexpression in conferring salinity tolerance in transgenic tobacco. We now
demonstrate the feasibility of same in a crop like rice through overproduction of glyoxalase II. The rice glyoxalase II was
cloned in pCAMBIA1304 and transformed into rice (Oryza sativa cv PB1) via Agrobacterium. The transgenic plants showed higher constitutive activity of glyoxalase II that increased further
upon salt stress, reflecting the upregulation of endogenous glyoxalase II. The transgenic rice showed higher tolerance to
toxic concentrations of methylglyoxal (MG) and NaCl. Compared with non-transgenics, transgenic plants at the T1 generation
exhibited sustained growth and more favorable ion balance under salt stress conditions.
Sneh L. Singla-Pareek and Sudesh Kumar Yadav have contributed equally to this work. 相似文献
68.
The migration of vascular endothelial cells plays a critical role in a variety of vascular physiological and pathological processes, such as embryonic development, angiogenesis, wound healing, re-endothelialization, and vascular remodeling. This study clarified the role and mechanism of a new vascular homeostasis regulator, Cellular repressor of E1A-stimulated genes (CREG), in the migration of primary human umbilical vein endothelial cells (HUVECs). A wound healing assay and transwell migration model showed that upregulation of CREG expression induced HUVEC migration and it was positively correlated with the expression of vascular endothelial growth factor. Furthermore, wild type integrin-linked kinase reversed the poor mobility of CREG knock-down HUVECs; in contrast, kinase-dead integrin-linked kinase weakened the migration of HUVECs. We also studied the effect of CREG on HUVEC migration by the addition of an mTOR inhibitor, recombinant vascular endothelial growth factor165, neutralizing antibody of vascular endothelial growth factor165 and AKT siRNA, and we concluded that CREG induces endothelial cell migration by activating the integrin-linked kinase/AKT/mTOR/VEGF165 signaling pathway. 相似文献
69.
70.
Colletti PF Goyal Y Varman AM Feng X Wu B Tang YJ 《Biotechnology and bioengineering》2011,108(4):893-901
In the production of chemicals via microbial fermentation, achieving a high yield is one of the most important objectives. We developed a statistical model to analyze influential factors that determine product yield by compiling data obtained from engineered Escherichia coli developed within last 10 years. Using both numerical and ordinal variables (e.g., enzymatic steps, cultivation conditions, and genetic modifications) as input parameters, our model revealed that cultivation modes, nutrient supplementation, and oxygen conditions were the three significant factors for improving product yield. Generally, the model showed that product yield decreases as the number of enzymatic steps in the biosynthesis pathway increases (7-9% loss of yield per enzymatic step). Moreover, overexpression of enzymes or removal of competitive pathways (e.g., knockout) does not necessarily result in an amplification of product yield (P-value>0.1), possibly because of limited capacity in the biosynthesis pathway to accommodate an increase in flux. The model not only provides general guidelines for metabolic engineering and fermentation processes, but also allows a priori estimation and comparison of product yields under designed cultivation conditions. 相似文献