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31.
Aissa I Bouaziz M Ghamgui H Kamoun A Miled N Sayadi S Gargouri Y 《Journal of agricultural and food chemistry》2007,55(25):10298-10305
The ability of a noncommercial immobilized lipase from Staphylococcus xylosus (SXLi) to catalyze the transesterification of tyrosol and ethyl acetate was investigated. Response surface methodology was used to evaluate the effects of the temperature (40-60 degrees C), the enzyme amount (50-500 UI), and the ethyl acetate/hexane volume ratio (0.2-1) on the tyrosol acetylation conversion yield. Two independent replicates were carried out under the optimal conditions predicted by the model (reaction temperature 54 degrees C, enzyme amount 500 UI, and volume ratio ethyl acetate/hexane 0.2). The maximum conversion yield reached 95.36 +/- 3.6%, which agreed with the expected value (96.8 +/- 3.7%). The ester obtained was characterized by spectroscopic methods. Chemical acetylation of tyrosol was performed, and the products were separated using HPLC. Among the eluted products from HPLC, mono- and diacetylated derivatives were identified by positive mass spectrometry. Tyrosol and its monoacetylated derivative exert similar antiradicalar activity on 2,2-diphenyl-1-picrylhydrazyle. 相似文献
32.
Dissolution of wood in ionic liquids 总被引:10,自引:0,他引:10
Kilpeläinen I Xie H King A Granstrom M Heikkinen S Argyropoulos DS 《Journal of agricultural and food chemistry》2007,55(22):9142-9148
The present paper demonstrates that both hardwoods and softwoods are readily soluble in various imidazolium-based ionic liquids (ILs) under gentle conditions. More specifically, a variety of ionic liquids can only partially dissolve wood chips, whereas ionic liquids such as 1-butyl-3-methylimidazolium chloride and 1-allyl-3-methylimidazolium chloride have good solvating power for Norway spruce sawdust and Norway spruce and Southern pine thermomechanical pulp (TMP) fibers. Despite the fact that the obtained solutions were not fully clear, these ionic liquids provided solutions which permitted the complete acetylation of the wood. Alternatively, transparent amber solutions of wood could be obtained when the dissolution of the same lignocellulosic samples was attempted in 1-benzyl-3-methylimidazolium chloride. This realization was based on a designed augmented interaction of the aromatic character of the cation of the ionic liquid with the lignin in the wood. After dissolution, wood can be regenerated as an amorphous mixture of its original components. The cellulose of the regenerated wood can be efficiently digested to glucose by a cellulase enzymatic hydrolysis treatment. Furthermore, completely acetylated wood was found to be readily soluble in chloroform, allowing, for the first time, detailed proton nuclear magnetic resonance (NMR) spectra and NMR diffusion measurements to be made. It was thus demonstrated that the dissolution of wood in ionic liquids now offers a variety of new possibilities for its structural and macromolecular characterization, without the prior isolation of its individual components. Furthermore, considering the relatively wide solubility and compatibility of ionic liquids with many organic or inorganic functional chemicals or polymers, it is envisaged that this research could create a variety of new strategies for converting abundant woody biomass to valuable biofuels, chemicals, and novel functional composite biomaterials. 相似文献
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The aim of this study was to determine the seroprevalence of hypodermosis in cattle in the east and southeast of Turkey. For this purpose, a total of 634 sera samples of cattle were collected from Malatya, Elazig and Diyarbakir provinces of east and southeast of Turkey from November 2005 to February 2006. The sera were analyzed using a Hypodermin C antigen by means of indirect ELISA. One hundred and forty eight (23.3%) out of 634 cattle were seropositive for hypoderma antibodies. The highest percentage of seropositivity were detected at Elazig province (26.3%) followed by Malatya (22.3%) and Diyarbakir provinces (22.1%). The seropositivity rate was higher in female (31%) than male (14.1%). When the mean is considered by animal breed, the highest seropositivity was detected at local breed (27.7%) following crossbreed (26.8%) and purebreed (19.7%). There was a positive relation between age and seropositivity. Seropositivity rate was 15.9% in 2 and under ages while these rates were 38.1% and 30.4% in 3-4 ages and 5 and up ages, respectively. 相似文献
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Prevalence and antimicrobial resistance of Campylobacter coli isolated from fattening pigs in France
Campylobacter are a leading cause of human diarrhea. The usual source of infection is contaminated food, particularly poultry but pork has also been described. The veterinary use of antimicrobial drugs has been suggested to be largely responsible for resistance in human isolates of this zoonotic pathogen. A study was carried out to investigate the occurrence and antimicrobial resistance of Campylobacter isolated from French fattening pigs. From March 1998 to June 1999, stomach samples were collected at slaughter from 240 fattening pigs originating from 24 different farms. Half of the pigs were found to be positive for Campylobacter but considerable variation was observed between farms. Isolates all belong to the Campylobacter coli species. Susceptibilities of the strains were determined for five antimicrobial drugs using agar dilution. Resistance to tetracycline and erythromycin was high (79 and 55%, respectively). For nalidixic acid, enrofloxacin and ampicillin, resistance was observed in 34, 15 and 20% of the isolates, respectively. More than one-third of the strains was resistant to at least three antimicrobial drugs. A Thr86Ile modification in GyrA was observed in the enrofloxacin-resistant strains studied. The multiresistant strains analyzed expressed the multidrug transporter CmeB at a high level. Results indicated a high prevalence of C. coli in the stomach of the French pigs examined. In addition, a high proportion of the strains was resistant to antimicrobial drugs, particularly to tetracycline and erythromycin, or were multiresistant. 相似文献
39.
Two accessions of Lycopersicon peruvianum Mill. (PI270435, PI126443) carrying Mi-2 and Mi-3, respectively, new root-knot nematode
resistance genes, were selected as the male parents for crosses with L. esculentum Mill. in order to produce interspecific
hybrids. Crossability barriers between these two distantly related species were circumvented by ovule culture. A total of
ten interspecific F1 hybrid plants were produced. The hybrid nature of the putative F1 plants was confirmed by a comparison of several morphological characteristics and a PCR-based assay. Eight of ten hybrid
plants were backcrossed with L. esculentum to generate a total of 98 BC1 progeny. Two lines were advanced to the BC2 and BC3 levels. Based on these results, ovule culture was found to be an effective method for the production of novel interspecific
F1 and BC1 plants.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
40.
Comparative fine mapping of fruit quality QTLs on chromosome 4 introgressions derived from two wild tomato species 总被引:6,自引:0,他引:6
Heather E. Yates Anne Frary Sami Doganlar Anna Frampton Nancy T. Eannetta John Uhlig Steven D. Tanksley 《Euphytica》2004,135(3):283-296
Despite their unsuitability for agricultural production, the wild relatives of crop species represent a largely untapped resource
of novel QTLs potentially useful for crop plant improvement. In this regard, previous introgression studies, involving several
different wild tomato species, have shown that the long arm of chromosome 4 contains QTLs for many horticulturally important
traits including soluble solids content, fruit shape, lycopene content and biochemical composition. However, these earlier
studies were unable to determine how many genes control these traits and whether genes affecting the same character from different
wild species are allelic or not. In an effort to shed light on these issues,we have constructed a series of lines containing
small, overlapping introgressions for portions of the long arm of chromosome 4 from L. peruvianum and L. hirsutum and tested these lines in replicated field trials. The results provide evidence for multiple, non-allelic loci controlling
soluble solids and fruit weight. They also show that the loci controlling some traits (e.g. fruit shape, fruit weight, epidermal
reticulation) co-localize to the same portions of chromosome 4, a result that maybe attributed to pleiotropy and/or gene dense
areas with lower than average recombination. The implications of these finding for molecular breeding and utilization of exotic
germplasm are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献