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21.
Discovery and directed evolution of a glyphosate tolerance gene 总被引:2,自引:0,他引:2
Castle LA Siehl DL Gorton R Patten PA Chen YH Bertain S Cho HJ Duck N Wong J Liu D Lassner MW 《Science (New York, N.Y.)》2004,304(5674):1151-1154
The herbicide glyphosate is effectively detoxified by N-acetylation. We screened a collection of microbial isolates and discovered enzymes exhibiting glyphosate N-acetyltransferase (GAT) activity. Kinetic properties of the discovered enzymes were insufficient to confer glyphosate tolerance to transgenic organisms. Eleven iterations of DNA shuffling improved enzyme efficiency by nearly four orders of magnitude from 0.87 mM-1 min-1 to 8320 mM-1 min-1. From the fifth iteration and beyond, GAT enzymes conferred increasing glyphosate tolerance to Escherichia coli, Arabidopsis, tobacco, and maize. Glyphosate acetylation provides an alternative strategy for supporting glyphosate use on crops. 相似文献
22.
23.
Availability of Heavy Metals for Brassica Chinensis Grown in an Acidic Loamy Soil Amended with a Domestic and an Industrial Sewage Sludge 总被引:1,自引:0,他引:1
The use of sewage sludge on agriculture provides an alternativefor sewage sludge disposal. Therefore, it was the aim of thepresent study to evaluate the feasibility of using a domestic(Tai Po sludge) and an industrial (Yuen Long sludge) sewagesludge produced in Hong Kong for the growth of vegetable crops.The acidic loamy soil with or without lime treatment was amendedseparately with each sludge at application rates of 0, 5, 10, 25and 50% (v/v) for the growth of a common local vegetable crop,Brassica chinensis. The plant available metal contents, asindicated by the DTPA extraction, increased with an increase insludge amendment, but decreased with lime amendment at eachsludge application rate due to the reduced metal availabilityat a higher pH. Sludge amendment enhanced the dry weight yieldof B. chinensis and the increase was more obvious for thesoil with lime treatment. The industrial sludge caused a loweryield than that of the domestic sludge amendment and asignificant reduction in yield at high application rates of YuenLong sludge was also noted. Tissue heavy metal contents, exceptfor Fe, increased as the sludge amendment rate increased whileplant grown in Yuen Long sludge amended soil contained higher Crand Zn contents at each sludge application rate. Liming the soilreduced the heavy metal contents in the plant tissues, exceptfor Fe, which were all below the allowable levels for vegetablecrops. The present experiment demonstrates that liming wasimportant in facilitating the growth of B. chinensis in sludge amended soil. The optimal sludge amendment rate for thesoil with lime amendment was 25% Tai Po sludge and 10% YuenLong sludge, while for the soil without lime amendment was 10% and5%, respectively. 相似文献
24.
25.
Wong CY 《Science (New York, N.Y.)》1939,89(2314):417-418
26.
Age-related changes in mitogen-induced lymphocyte proliferation and polymorphonuclear neutrophil function in the piglet 总被引:5,自引:0,他引:5
Changes in concentration of plasma cortisol, mitogen-induced lymphocyte proliferation and the phagocytic and killing abilities of polymorphonuclear neutrophils (PMN) were assessed in 24 crossbred piglets at .5, 1, 3 and 6 wk of age. Concentrations of blood cortisol were high at birth but decreased (P less than .001) thereafter. Spontaneous lymphocyte proliferation was approximately 10-fold higher in the newborn than in pigs 6 wk old. The methods by which data on lymphocyte proliferation were expressed greatly influenced the results of the age-related changes in lymphocyte response. When lymphocyte proliferation was expressed as a stimulation index, there was an increase in mitogen-induced lymphocyte proliferation with advancing age. However, when lymphocyte proliferation was expressed as total counts per minute, mitogen-induced lymphocyte proliferation decreased with increasing age. In general, no significant age-related changes were observed in PMN function except for a transient decrease in PMN phagocytic ability at wk 3. Piglets were born with high concentrations of blood cortisol; this was associated with age-related changes in lymphocyte proliferation. 相似文献
27.
D Sisson G Dilling M M Wong W P Thomas 《American journal of veterinary research》1985,46(7):1529-1533
Ninety dogs naturally infected with Dirofilaria immitis and 103 noninfected dogs, as determined by necropsy, were used to compare the sensitivity and specificity of the cuticular and somatic reactions of the indirect fluorescent antibody test (IFA-C and IFA-S, respectively) and 2 enzyme-linked immunosorbent assays (ELISA). In microfilaremic and amicrofilaremic heartworm-infected dogs, negative results were common for all serotests. In dogs without adult heartworms at necropsy, 32% to 49% were positive, using 1 ELISA, 27% to 29% were positive with the other ELISA, 15% to 36% were positive with the IFA-S, and 0% to 1% were positive using the IFA-C, depending on the classification of borderline reactions. The prevalence of false positive serotests was probably not due to the detection of precardial stages of D immitis in dogs obtained from areas of low endemicity. Until the causes of the false-positive tests are resolved, the use of currently available serotests for routine diagnostic screening or as criteria for instituting treatment is not recommended. 相似文献
28.
29.
W.‐L. Hsu Y.‐S. Lin Y.‐Y. Hu M.‐L. Wong F.‐Y. Lin Y.‐J. Lee 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2014,28(2):437-442
Background
Neutrophil gelatinase–associated lipocalin (NGAL) is released from renal tubular cells after injury and serves in humans as a real‐time indicator of active kidney damage, including acute kidney injury (AKI) and chronic kidney disease (CKD). However, NGAL concentrations in dogs with naturally occurring AKI or CKD rarely have been explored in detail.Hypothesis/Objectives
The goal of this study was to evaluate whether NGAL can serve as a useful biomarker in dogs with naturally occurring renal disease.Animals
Client‐owned dogs with renal disease (57) and control dogs without any disease (12) were examined.Methods
Serum NGAL (sNGAL) and urine NGAL (uNGAL) concentrations were measured in each animal by a newly developed ELISA system. Demographic, hematologic, and serum biochemical data were recorded. Survival attributable to AKI and CKD was evaluated at 30 days and 90 days, respectively.Results
Serum and urine NGAL concentrations in azotemic dogs were significantly higher than in nonazotemic dogs and were highly correlated with serum creatinine concentration (P < .05). Among CKD dogs, death was associated with significantly higher sNGAL and uNGAL concentrations compared with survivors. Receiver‐operating characteristic curve (ROC) analysis showed that sNGAL was better than serum creatinine concentration when predicting clinical outcomes for CKD dogs (P < .05). The best cutoff point for sNGAL was 50.6 ng/mL, which gave a sensitivity and a specificity of 76.9 and 100%, respectively. Furthermore, dogs that had higher concentrations of sNGAL survived for a significantly shorter time.Conclusion
sNGAL is a useful prognostic marker when evaluating dogs with CKD. 相似文献30.
D.J. Chung A. Wong K. Hayashi C.E. Yellowley 《Veterinary journal (London, England : 1997)》2014,199(1):123-130
Adipose tissue-derived mesenchymal stromal cells (AT-MSCs) are good candidates for cell therapy due to the accessibility of fat tissue and the abundance of AT-MSCs therein. Neurospheres are free-floating spherical condensations of cells with neural stem/progenitor cell (NSPC) characteristics that can be derived from AT-MSCs. The aims of this study were to examine the influence of oxygen (O2) tension on generation of neurospheres from canine AT-MSCs (AT-cMSCs) and to develop a hypoxic cell culture system to enhance the survival and therapeutic benefit of generated neurospheres.AT-cMSCs were cultured under varying oxygen tensions (1%, 5% and 21%) in a neurosphere culture system. Neurosphere number and area were evaluated and NSPC markers were quantified using real-time quantitative PCR (qPCR). Effects of oxygen on neurosphere expression of hypoxia inducible factor 1, α subunit (HIF1A) and its target genes, erythropoietin receptor (EPOR), chemokine (C-X-C motif) receptor 4 (CXCR4) and vascular endothelial growth factor (VEGF), were quantified by qPCR. Neural differentiation potential was evaluated in 21% O2 by cell morphology and qPCR.Neurospheres were successfully generated from AT-cMSCs at all O2 tensions. Expression of nestin mRNA (NES) was significantly increased after neurosphere culture and was significantly higher in 1% O2 compared to 5% and 21% O2. Neurospheres cultured in 1% O2 had significantly increased levels of VEGF and EPOR. There was a significant increase in CXCR4 expression in neurospheres generated at all O2 tensions. Neurosphere culture under hypoxia had no negative effect on subsequent neural differentiation. This study suggests that generation of neurospheres under hypoxia could be beneficial when considering these cells for neurological cell therapies. 相似文献