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991.
David S. Waugh 《Protein science : a publication of the Protein Society》2016,25(3):559-571
Although chaperone‐assisted protein crystallization remains a comparatively rare undertaking, the number of crystal structures of polypeptides fused to maltose‐binding protein (MBP) that have been deposited in the Protein Data Bank (PDB) has grown dramatically during the past decade. Altogether, 102 fusion protein structures were detected by Basic Local Alignment Search Tool (BLAST) analysis. Collectively, these structures comprise a range of sizes, space groups, and resolutions that are typical of the PDB as a whole. While most of these MBP fusion proteins were equipped with short inter‐domain linkers to increase their rigidity, fusion proteins with long linkers have also been crystallized. In some cases, surface entropy reduction mutations in MBP appear to have facilitated the formation of crystals. A comparison of the structures of fused and unfused proteins, where both are available, reveals that MBP‐mediated structural distortions are very rare. 相似文献
992.
Hyaluronic acid (HA) production using a dairy industrial waste is a more cost-efficient strategy than using an expensive synthetic medium. In this study, we investigated the production of HA using Streptococcus thermophilus under shake flask conditions using dairy industrial waste as nutritional supplements, namely whey permeate (WP) and whey protein hydrolysate (WPH). Preliminary screening using Plackett–Burman design exhibited WP, WPH, initial pH, and inoculum size as significant factors influencing HA titer. Response surface methodology design of four factors was formulated at three levels for enhanced production of HA. Shake flask HA fermentation by S. thermophilus was performed under global optimized process conditions and the optimal HA titer (342.93?mg?L?1) corroborates with Box–Behnken design prediction. The molecular weight of HA was elucidated as 9.22–9.46?kDa. The ultralow-molecular weight HA reported in this study has a potential role in drug and gene delivery applications. 相似文献
993.
Dan Zhang Yanqing Luo Shaohua Chu Yuee Zhi Bin Wang 《Preparative biochemistry & biotechnology》2016,46(6):575-585
Biological pretreatment of rice straw and production of reducing sugars by hydrolysis of bio-pretreated material with Streptomyces griseorubens JSD-1 was investigated. After 10 days of incubation, various chemical compositions of inoculated rice straw were degraded and used for further enzymatic hydrolysis studies. The production of cellulolytic enzyme by S. griseorubens JSD-1 favored the conversion of cellulose to reducing sugars. The culture medium for cellulolytic enzyme production by using agro-industrial wastes was optimized through response surface methodology. According to the response surface analysis, the concentrations of 11.13, 20.34, 4.61, and 2.85 g L?1 for rice straw, wheat bran, peptone, and CaCO3, respectively, were found to be optimum for cellulase and xylanase production. Then the hydrolyzed spent Streptomyces cells were used as a nitrogen source and the maximum filter paper cellulase, carboxymethylcellulase, and xylanase activities of 25.79, 78.91, and 269.53 U mL?1 were achieved. The crude cellulase produced by S. griseorubens JSD-1 was subsequently used for the hydrolysis of bio-pretreated rice straw, and the optimum saccharification efficiency of 88.13% was obtained, indicating that the crude enzyme might be used instead of commercial cellulase during a saccharification process. These results give a basis for further study of bioethanol production from agricultural cellulosic waste. 相似文献
994.
995.
996.
Signaling induced by hop/STI-1 depends on endocytosis 总被引:2,自引:0,他引:2
Americo TA Chiarini LB Linden R 《Biochemical and biophysical research communications》2007,358(2):620-625
The co-chaperone hop/STI-1 is a ligand of the cell surface prion protein (PrP(C)), and their interaction leads to signaling and biological effects. Among these, hop/STI-1 induces proliferation of A172 glioblastoma cells, dependent on both PrP(C) and activation of the Erk pathway. We tested whether clathrin-mediated endocytosis affects signaling induced by hop/STI-1. Both hyperosmolarity induced by sucrose and monodansyl-cadaverine blocked Erk activity induced by hop/STI-1, without affecting the high basal Akt activity typical of A172. The endocytosis inhibitors also affected the sub-cellular distribution of phosphorylated Erk, consistent with blockade of the latter's activity. The data indicate that signaling induced by hop/STI-1 depends on endocytosis. These findings are consistent with a role of sub-cellular trafficking in signal transduction following engagement by PrP(C) by ligands such as hop/STI-1, and may help help unravel both the functions of the prion protein, as well as possible loss-of-function components of prion diseases. 相似文献
997.
Nitric oxide decreases cell surface expression of aquaporin-5 and membrane water permeability in lung epithelial cells 总被引:4,自引:0,他引:4
Nagai K Watanabe M Seto M Hisatsune A Miyata T Isohama Y 《Biochemical and biophysical research communications》2007,354(2):579-584
Nitric oxide (NO) is implicated in the pathogenesis of lung inflammation and edema. In this study, the effects of nitric oxide (NO)-donors on membrane water permeability and cell surface expression of aquaporin-5 (AQP5) in mouse lung epithelial cells were examined. NO-donors, GSNO and NOC-18 decreased cell surface expression of AQP5, concentration- and time-dependently, whereas they did not affect the amount of AQP5 in whole cell lysates. The membrane water permeability of cells was also decreased by treatment with NO-donors. The decrease in cell surface AQP5 by NO was abolished by simultaneous treatment with methyl-beta-cyclodextrin, but not with ODQ, an inhibitor of the cGMP-dependent pathway. In addition, immunocytochemistry with anti-AQP5 indicated that NO changed AQP5 localization from the plasma membrane to the intracellular fraction. These data indicate that NO stimulates AQP5 internalization from the plasma membrane through a cGMP-independent mechanism, and decreases membrane water permeability. 相似文献
998.
Culture of Papaver somniferum in vitro was used for a characterisation of cell surface structures and mode of cell adhesion and cell separation during cell differentiation
and plant regeneration in somatic embryogenesis and shoot organogenesis. In early stages of somatic embryogenesis, cell type-specific
and developmentally regulated change of cell morphogenesis was demonstrated. Cell wall of separated embryonic cells were self-covered
with external tubular network, whereas morphogenetic co-ordination of adhered cells of somatic proembryos was supported by
fine and fibrillar external cell wall continuum of peripheral cells, interconnecting also local sites of cell separation.
Such type of cell contacts disappeared during histogenesis, when the protodermis formation took place. Tight cell adhesion
of activated cells with polar cell wall thickening, and production of extent mucilage on the periphery were the crucial aspects
of meristemoids. Fine amorphous layer covered developing shoot primordia, but we have not observed such comparable external
fibrillar network. On the contrary intercellular separation of differentiated cells in regenerated organs, and accepting distinct
developmental system of somatic embryogenesis and shoot organogenesis, cell adhesion in early stages and ultrastructural changes
associated with tissue disorganisation, and the subsequent reorganisation into either embryos or shoots appear to be regulatory
morphogenetical events of plant regeneration in vitro. 相似文献
999.
Marco Gobbettia Rosalba Lanciotti Maria De Angelis Maria Rosaria Corbo Roberto Massini Patrick Fox 《Enzyme and microbial technology》1999,25(10):897-809
The individual and interactive effects of temperature, pH, NaCl, and aw on the proteolytic and lipolytic activities of Lactobacillus delbrueckii subsp. bulgaricus B397, Lactococcus lactis subsp. lactis T12, and Lb. plantarum 2739 were studied by quadratic response surface methodology. The effects on enzyme activities depended on the interactions among the independent variables, type of activity, substrate and, especially, species. The proteinase activity of strains B397 and T12 was affected differently by pH as individual or interactive terms depending on the type of substrate sl- or β-casein. The increase of NaCl concentration (2.5–7.5%) under cheese-like conditions had a negative effect on the proteinase activity of strain T12. The effect of NaCl was related to the corresponding decrease in aw. Aminopeptidases N and A, iminopeptidase and endopeptidase of Lc. lactis subsp. lactis T12 were strongly inhibited by pH 5–6 and NaCl concentration higher than 3.75%. The negative effects of these independent variables was in several cases enhanced by their interaction and/or by the interaction with the lowest temperatures. In contrast, the same peptidases of Lb. plantarum 2739 retained a high activity under the very hostile environmental conditions. Iminopeptidase and especially endopeptidase activities of strain 2739 were stimulated slightly by NaCl at concentrations up to 5%. Lipase/esterase activity of Lb. delbrueckii subsp. bulgaricus B397 was markedly inhibited under cheese-like conditions. 相似文献
1000.
Santacruz-Ruvalcaba Fernando Gutiérrez-Pulido Humberto Rodríguez-Garay Benjamin 《Plant Cell, Tissue and Organ Culture》1999,56(3):163-167
An efficient method for the in vitro propagation of Agave parrasana Berger, an important ornamental plant species native to
the state of Coahuila, México, was developed. Proliferation of good quality shoots was achieved on agar-solidified basal MS
medium supplemented with L2 vitamins and 13.3 μM benzyladenine. Rooting was successful in the basal medium with no growth regulators; however, a light
intensity of 100 μmol m-2 s-1 was found to promote better rooting than 25 μmol m-2 s-1.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献