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C. S. Chidan Kumar Wan-Sin Loh Siddegowda Chandraju Yip-Foo Win Weng Kang Tan Ching Kheng Quah Hoong-Kun Fun 《PloS one》2015,10(3)
A series of N-ethyl phthalimide esters 4(a-n) were synthesized and characterized by spectroscopic studies. Further, the molecular structure of majority of compounds were analysed by single crystal X-ray diffraction studies. The X-ray analysis revealed the importance of substituents on the crystal stability and molecular packing. All the synthesized compounds were tested for in vitro antioxidant activity by DPPH radical scavenging, FRAP and CUPRAC methods. Few of them have shown good antioxidant activity. 相似文献
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Low KO Mahadi NM Rahim RA Rabu A Abu Bakar FD Murad AM Illias RM 《Journal of industrial microbiology & biotechnology》2011,38(9):1587-1597
Direct transport of recombinant protein from cytosol to extracellular medium offers great advantages, such as high specific
activity and a simple purification step. This work presents an investigation on the potential of an ABC (ATP-binding cassette)
transporter system, the hemolysin transport system, for efficient protein secretion in Escherichia coli (E. coli). A higher secretory production of recombinant cyclodextrin glucanotransferase (CGTase) was achieved by a new plasmid design
and subsequently by optimization of culture conditions via central composite design. An improvement of at least fourfold extracellular
recombinant CGTase was obtained using the new plasmid design. The optimization process consisted of 20 experiments involving
six star points and six replicates at the central point. The predicted optimum culture conditions for maximum recombinant
CGTase secretion were found to be 25.76 μM IPTG, 1.0% (w/v) arabinose and 34.7°C post-induction temperature, with a predicted
extracellular CGTase activity of 68.76 U/ml. Validation of the model gave an extracellular CGTase activity of 69.15 ± 0.71 U/ml,
resulting in a 3.45-fold increase compared to the initial conditions. This corresponded to an extracellular CGTase yield of
about 0.58 mg/l. We showed that a synergistic balance of transported protein and secretory pathway is important for efficient
protein transport. In addition, we also demonstrated the first successful removal of the C-terminal secretion signal from the transported fusion protein by thrombin proteolytic cleavage. 相似文献
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Chowdhury R Yeoh KK Tian YM Hillringhaus L Bagg EA Rose NR Leung IK Li XS Woon EC Yang M McDonough MA King ON Clifton IJ Klose RJ Claridge TD Ratcliffe PJ Schofield CJ Kawamura A 《EMBO reports》2011,12(5):463-469
Mutations in isocitrate dehydrogenases (IDHs) have a gain-of-function effect leading to R(−)-2-hydroxyglutarate (R-2HG) accumulation. By using biochemical, structural and cellular assays, we show that either or both R- and S-2HG inhibit 2-oxoglutarate (2OG)-dependent oxygenases with varying potencies. Half-maximal inhibitory concentration (IC50) values for the R-form of 2HG varied from approximately 25 μM for the histone Nɛ-lysine demethylase JMJD2A to more than 5 mM for the hypoxia-inducible factor (HIF) prolyl hydroxylase. The results indicate that candidate oncogenic pathways in IDH-associated malignancy should include those that are regulated by other 2OG oxygenases than HIF hydroxylases, in particular those involving the regulation of histone methylation. 相似文献
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Microbial transformation of the sesquiterpenoid (-)-maalioxide by the fungus Mucor plumbeus gave three metabolites, 9beta-hydroxymaalioxide, 1beta-hydroxymaalioxide and 7beta-hydroxymaalioxide. 9beta-hydroxymaalioxide and its structure was established on the basis of its spectroscopic properties and chemical reactions. 相似文献
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Z Zainal-Abidin PD Veith SG Dashper Y Zhu DV Catmull YY Chen DC Heryanto D Chen JS Pyke K Tan HL Mitchell EC Reynolds 《Journal of proteome research》2012,11(9):4449-4464
Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia exist in a polymicrobial biofilm associated with chronic periodontitis. The aim of this study was to culture these three species as a polymicrobial biofilm and to determine proteins important for bacterial interactions. In a flow cell all three species attached and grew as a biofilm; however, after 90 h of culture P. gingivalis and T. denticola were closely associated and dominated the polymicrobial biofilm. For comparison, planktonic cultures of P. gingivalis and T. denticola were grown separately in continuous culture. Whole cell lysates were subjected to SDS-PAGE, followed by in-gel proteolytic H(2)(16)O/H(2)(18)O labeling. From two replicates, 135 and 174 P. gingivalis proteins and 134 and 194 T. denticola proteins were quantified by LC-MALDI TOF/TOF MS. The results suggest a change of strategy in iron acquisition by P. gingivalis due to large increases in the abundance of HusA and HusB in the polymicrobial biofilm while HmuY and other iron/haem transport systems decreased. Significant changes in the abundance of peptidases and enzymes involved in glutamate and glycine catabolism suggest syntrophy. These data indicate an intimate association between P. gingivalis and T. denticola in a biofilm that may play a role in disease pathogenesis. 相似文献
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Fusarium graminearum Schwabe is the primary cause of Fusarium head blight (FHB) in North America. Chemically distinct F. graminearum sub-populations can be identified based on the type or composition of deoxynivalenol (DON) mycotoxin derivatives, including
3-acetyl (3-ADON) and 15-acetyl (15-ADON). The evaluation of randomly selected 3-ADON and 15-ADON isolates, collected from
spring wheat throughout Canada, was performed using thin layer chromatography (TLC), high-performance liquid chromatography
(HPLC), ice-nucleation activity (INA), and heat and cold tolerance tests conducted within a temperature range of −70°C to
65°C. The results indicated that the 3-ADON sub-population, which is responsible for the highest disease severity and has
rapidly displaced the 15-ADON sub-population, produces more DON and zearalenone (ZEA) than the 15-ADON sub-population when
exposed to heat and cold. Following exposures (1 and 2 h) to extremely high or low temperatures, 3-ADON isolates exhibited
faster mycelial growth than 15-ADON isolates. In addition, the warmest temperature at which INA activity occurred was in 3-ADON
(−3.6°C) vs. 15-ADON (−5.1°C). Taken together, these features suggest that the newly emerging 3-ADON sub-population is more
resilient than the resident 15-ADON sub-population. Overall, the differences between the two sub-populations could provide
new insights into FHB epidemiology and if validated under field conditions, may provide important information for predicting
future FHB epidemics. 相似文献
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Houle Wang Kheng B. Lim Ross F. Lawrence William N. Howald J.Alex Taylor Lowell H. Ericsson Kenneth A. Walsh Murray Hackett 《Analytical biochemistry》1997,250(2):162
Electrospray ionization sources, used with triple quadrupole mass spectrometers from PE/Sciex (API III+), Micromass (Quattro II), and Finnigan (TSQ 7000), were modified with a 35-gauge stainless steel needle. The dimensions of the needle were 63 μm i.d. by 145 μm o.d. with variable length, depending on the specific instrument. This modification led to enhanced signal stability, improved signal/noise ratios, and lowered sample consumption for a wide range of peptides. Stable baselines were observed with flow rates in the range of 50 nL/min to 5 μL/min. An alternative design, based on a metal wire housed within a fused silica capillary, led to the most stable signals of all during infusion, but caused excessive peak broadening with capillary chromatography. The Finnigan interface was further modified with an external postcolumn addition tee, used in conjunction with capillary liquid chromatography columns of 30 and 50 μm internal diameter. The best results with the modified Finnigan interface were acquired using the 50-μm column at a flow rate of 150 to 200 nL/min. 相似文献
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Zi Yan Chen Yit Kheng Goh You Keng Goh Kah Joo Goh 《Archives Of Phytopathology And Plant Protection》2017,50(11-12):598-612
Ganoderma boninense basal stem rot poses a serious threat to the oil palm industry. The effects of external disease symptoms and coastal soils (Briah – Typic Endoaquepts, Jawa – Typic Sulfaquepts, and Selangor – Typic Humaquepts) on the life expectancy of the infected palms, from disease detection to death, were studied. Six-monthly censuses on disease classes for each palm were recorded between 2004 and 2012. Survival curves of disease symptoms and soil types were compared using Kaplan–Meier and log-rank methods, respectively. Ganoderma-infected palms in acid-sulphate (AS) and potential AS soils recorded lower life expectancy. Survival duration of infected palms with foliar symptoms was 12-months shorter. External factors, such as soil type may influence the survival of infected palms and soil types may pre-dispose oil palm to higher risk of Ganoderma infection. More effective Ganoderma management for palms planted on Coastal soils (with and without AS layer) have been proposed. 相似文献
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