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81.
Choline oxidase is a flavin-dependent enzyme that catalyzes the oxidation of choline to glycine-betaine, with oxygen as electron acceptor. Storage at pH 6 and -20 degrees C resulted in a change in the conformation of choline oxidase, which was associated with complete loss of catalytic activity when the enzyme was assayed at pH 6. Incubation of the inactive enzyme at pH values > or = 6.5 and 25 degrees C resulted in a fast and partial reactivation of the enzyme, which occurred with slow onset of steady state during enzymatic turnover. The rate of approaching steady state was independent of the concentrations of choline and enzyme, but increased to a limiting value with increasing pH, defining a pKa value of approximately 7.3 for an unprotonated group required for enzyme activation. Prolonged incubation of the inactive enzyme at pH 6 and temperatures > or = 20 degrees C, at which no hysteretic behavior was observed, resulted in the slow and full recovery of activity over 3 h, associated with a conformational change that reverted the enzyme to the native form. Activation of the enzyme at pH 6 was enthalpy-driven with deltaH(double dagger) and TdeltaS(double dagger) values of approximately 112 kJ mol(-1) and approximately 20 kJ mol(-1) determined at 25 degrees C. These data suggest that freezing the enzyme at low pH induces a localized and reversible conformational change that is associated with the complete and reversible loss of catalytic activity. 相似文献
82.
Thermophilic actinomycetes were isolated from sediment of the Chingshuei hot spring in north Taiwan, and the strain HS 45-1
was selected from colonies which formed distinct clear zones on agar plate with emulsified polyethylene succinate (PES). The
film of PES disappeared within 6 days in liquid cultures at 50°C. The strain HS 45-1 was also able to degrade poly (ε-carpolactone)
(PCL) and poly (3-hydroxybutyrate) (PHB) films completely within 6 days in liquid cultures. Basing on the results of phynotypic
characteristics, phylogenetic studies and DNA-DNA hybridization, strain HS 45-1 should be assigned to Micorbispora rosea subsp. taiwanensis. 相似文献
83.
Binh Tran Quang Linh Duong Tuan Chung Le Thi Kim Phuong Pham Tran Nga Bui Thi Thuy Ngoc Nguyen Anh Thuyen Tran Quang Tung Do Dinh Nhung Bui Thi 《Biochemical genetics》2022,60(2):707-719
Biochemical Genetics - The study aimed to evaluate the contribution of the FTO A/T polymorphism (rs9939609) to the prediction of the future type 2 diabetes (T2D). A population-based prospective... 相似文献
84.
Isolation of New Delhi metallo‐β‐lactamase 1‐producing Vibrio cholerae non‐O1, non‐O139 strain carrying ctxA,st and hly genes in southern Vietnam
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Tai The Diep Nhi Thi Ngoc Nguyen Thi Ngoc Cat Nguyen Huy Khac An Truong Quang Nguyen Vu Hoang Nguyen Thuong Van Nguyen Thu Ngoc Anh Nguyen Hidemasa Izumiya Makoto Ohnishi Tetsu Yamashiro Lan Thi Phuong Nguyen 《Microbiology and immunology》2015,59(5):262-267
Vibrio cholerae non‐O1, non‐O139 (VC_NAG) organisms are universally present in the aquatic environment and regarded as non‐pathogenic bacteria. However, considering that they do occasionally induce gastroenteritis, a study of their virulence and antibiotic resistance genes is important. The presence of enteropathogenic genes, including ctxA, VC_NAG‐specific heat‐stable toxin gene (st), hemolysin (hly), and zona occludens toxin (zot) was determined by PCR in 100 VC_NAG strains isolated in southern Vietnam in 2010–2013 from 94 environmental and six human origins. These 100 VC_NAG strains were also tested phenotypically and genotypically for the presence of the New Delhi metallo‐β‐lactamase (NDM‐1). Of the 100 VC_NAG strains tested, six were positive for ctxA; five from the environment and one of human origin. The st gene was detected in 17 isolates, 15 and two of which were of environmental and human origins, respectively. Gene hly was detected in 19 VC_NAG strains examined, two of which were isolated from humans and 17 from environments. The zot gene was not detected in any of the strains tested. Three VC_NAG strains of environmental origin were confirmed to produce NDM‐1 and the blaNDM‐1 gene was detected in those strains by PCR. Of note, one of the three NDM‐1‐producing VC_NAG strains was confirmed to carry ctxA, st and hly genes concurrently. This is the first report of isolation of NDM‐1‐producing VC_NAG strains in Vietnam. 相似文献
85.
Gilbert Richarme Mouadh Mihoub Julien Dairou Linh Chi Bui Thibaut Leger Aazdine Lamouri 《The Journal of biological chemistry》2015,290(3):1885-1897
Glycation is an inevitable nonenzymatic covalent reaction between proteins and endogenous reducing sugars or dicarbonyls (methylglyoxal, glyoxal) that results in protein inactivation. DJ-1 was reported to be a multifunctional oxidative stress response protein with poorly defined function. Here, we show that human DJ-1 is a protein deglycase that repairs methylglyoxal- and glyoxal-glycated amino acids and proteins by acting on early glycation intermediates and releases repaired proteins and lactate or glycolate, respectively. DJ-1 deglycates cysteines, arginines, and lysines (the three major glycated amino acids) of serum albumin, glyceraldehyde-3-phosphate dehydrogenase, aldolase, and aspartate aminotransferase and thus reactivates these proteins. DJ-1 prevented protein glycation in an Escherichia coli mutant deficient in the DJ-1 homolog YajL and restored cell viability in glucose-containing media. These results suggest that DJ-1-associated Parkinsonism results from excessive protein glycation and establishes DJ-1 as a major anti-glycation and anti-aging protein. 相似文献
86.
Jong-Yil Chai Woon-Mok Sohn Byoung-Kuk Na Jong-Bok Park Hoo-Gn Jeoung Eui-Hyug Hoang Thi Thi Htoon Htay Htay Tin 《The Korean journal of parasitology》2015,53(5):619-625
The present study was performed to determine the infection status of swamp eels with Gnathostoma sp. larvae in Myanmar. We purchased total 37 Asian swamp eels, Monopterus albus, from a local market in Yangon in June and December 2013 and 2014. All collected eels were transferred with ice to our laboratory and each of them was examined by the artificial digestion technique. A total of 401 larval gnathostomes (1-96 larvae/eel) were detected in 33 (89.2%) swamp eels. Most of the larvae (n=383; 95.5%) were found in the muscle. The remaining 18 larvae were detected in the viscera. The advanced third-stage larvae (AdL3) were 2.3-4.4 mm long and 0.25-0.425 mm wide. The characteristic head bulb (0.093 × 0.221 mm in average size) with 4 rows of hooklets, muscular long esophagus (1.025 mm), and 2 pairs of cervical sacs (0.574 mm) were observed by light microscopy. The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. As scanning electron microscopic findings, the characteristic 4-5 rows of hooklets on the head bulb, a cervical papilla, tegumental spines regularly arranged in the transverse striations, and an anus were well observed. Based on these morphological characters, they were identified as the AdL3 of Gnathostoma spinigerum. By the present study, it has been confirmed for the first time that Asian swamp eels, M. albus, from Yangon, Myanmar are heavily infected with G. spinigerum larvae. 相似文献
87.
88.
89.
Nguyen Hoang Loc Le Thi Thinh Moon-Sik Yang Tae-Geum Kim 《Biotechnology and Bioprocess Engineering》2011,16(3):576-580
The cholera toxin B subunit (CTB), a nontoxic molecule with potent biological properties, is a powerful mucosal and parenteral
adjuvant that induces a strong immune response against co-administered or coupled antigens. A gene encoding CTB, which was
modified based on the optimized codon usage in the plant, was synthesized and fused to the endoplasmic reticulum retention
signal KDEL to enhance its expression level in plants. The synthetic CTB (sCTB) gene was introduced into a plant expression
vector adjacent to the CaMV 35S promoter, and was transformed into tomato using an Agrobacterium-mediated transformation method. The integration of the sCTB gene into the genomic DNA of transgenic plants was confirmed
by genomic DNA PCR amplification. The synthesis and assembly of CTB protein in transgenic plants was demonstrated through
immunoblot analysis and GM1-ELISA. The highest amount of CTB protein produced in transgenic tomatoes was approximately 0.9% of total soluble fruit protein
which was 10-fold greater than the previously 0.081%. GM1-ELISA indicated that plant-synthesized CTB protein bound specifically to GM1-gangliosides, suggesting that the CTB subunits formed active pentamers. 相似文献
90.
Cuong HQ Hien NT Duong TN Phong TV Cam NN Farrar J Nam VS Thai KT Horby P 《PLoS neglected tropical diseases》2011,5(9):e1322