Determination of hydrolyzable tannins (gallotannins and ellagitannins) after reaction with potassium iodate     

Hartzfeld PW  Forkner R  Hunter MD  Hagerman AE 《Journal of agricultural and food chemistry》2002,50(7):1785-1790

A widely used method for analyzing hydrolyzable tannins afer reaction with KIO(3) has been modified to include a methanolysis step followed by oxidation with KIO(3). In the new method, hydrolyzable tannins (gallotannins and ellagitannins) are reacted at 85 degrees C for 20 h in methanol/sulfuric acid to quantitatively release methyl gallate. Dried plant samples can be methanolyzed under the same conditions to convert hydrolyzable tannins to methyl gallate. Oxidation of the methyl gallate by KIO(3) at pH 5.5, 30 degrees C, forms a chromophore with lambda(max) 525 nm, which is determined spectrophotometrically. The detection limit of the method is 1.5 microg of methyl gallate, and with plant samples, relative standard deviations of less than 3% were obtained.  相似文献   

Interaction of flavonoids with bovine serum albumin: a fluorescence quenching study   总被引：6，自引：0，他引：6  

Papadopoulou A  Green RJ  Frazier RA 《Journal of agricultural and food chemistry》2005,53(1):158-163

The interaction between four flavonoids (catechin, epicatechin, rutin, and quercetin) and bovine serum albumin (BSA) was investigated using tryptophan fluorescence quenching. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between the flavonoids and BSA. The binding affinity was strongest for quercetin and ranked in the order quercetin > rutin > epicatechin = catechin. The pH in the range of 5-7.4 does not affect significantly (p < 0.05) the association of rutin, epicatechin, and catechin with BSA, but quercetin exhibited a stronger affinity at pH 7.4 than at lower pH (p < 0.05). Quercetin has a total quenching effect on BSA tryptophan fluorescence at a molar ratio of 10:1 and rutin at approximately 25:1. However, epicatechin and catechin did not fully quench tryptophan fluorescence over the concentration range studied. Furthermore, the data suggested that the association between flavonoids and BSA did not change molecular conformation of BSA and that hydrogen bonding, ionic, and hydrophobic interaction are equally important driving forces for protein-flavonoid association.  相似文献   

WCVM GLOBAL VETS          下载免费PDF全文

Mairead Drain  Emma Agg  Leanne Boyd  Suzanne Lynde  Rebecca Korven  Karen Kemp  Patrick Garcia  Sarah Flint    Shannon Burns 《The Canadian veterinary journal. La revue veterinaire canadienne》2003,44(2):121-122

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Responses of Juvenile Golden Shiner Notemigonus crysoleucas Fed Semipurified or Practical Diets With or Without Supplemental Ascorbic Acid     

Rebecca  Lochmann Harold  Phillips Konrad  Dabrowski Regis  Moreau 《Journal of the World Aquaculture Society》2001,32(2):202-209

A 12-wk feeding trial was conducted in a flow-through system to determine whether juvenile golden shiner Notemigonus crysoleucas have a dietary requirement for ascorbic acid. Triplicate groups of 30 fish each weighing 0.44 g initially were fed semi-purified (casein) diets supplemented with 0 or 250 mg ascorbic acid/kg, or practical (fish meal) diets supplemented with 0 or 250 mg ascorbic acid/kg. The form of ascorbic acid used was L-ascorbyl-2-polyphosphate. Survival was higher in fish fed the semi-purified diet with 250 mg ascorbic acid/kg than in those fed the unsupplemented semi-purified diet, while weight gain did not differ between treatments. Weight gain was higher in fish fed the practical (fish meal) diet supplemented with 250 mg ascorbic acid/kg than in those fed the unsupplemented practical diet, while survival did not differ between treatments. No other signs of ascorbic acid deficiency were observed, but fish fed the casein diets had skin and fin erosion indicative of a possible bacterial infection. Whole-body concentrations of ascorbic acid (total, reduced, and percent of reduced ascorbic acid) were higher in fish fed semi-purified or practical diets supplemented with 250 mg ascorbic acid/kg than in fish fed unsupplemented diets. Golden shiners appear to require a dietary source of ascorbic acid for growth or survival, depending on experimental conditions. The two main differences in the study were in diet composition (semi-purified versus practical diets) and apparent health status of fish fed the different diet types. Additional studies are needed to define requirements further.  相似文献   

Performance of a canine weight-loss program in clinical practice     

Saker KE  Remillard RL 《Veterinary therapeutics : research in applied veterinary medicine》2005,6(4):291-302

Two canine studies evaluating the effectiveness of a specific computerized weight reduction program in two different clinical settings are summarized to give an overall assessment of an obesity management software program. The weight loss program utilizes a low calorie food formulation (dry, canned and treat) and software to suggest daily calorie intake for weight loss. The software utilizes current body weight and a desired weekly rate of weight loss to predict the dog's body weight in 30 days. The dietary product and software were used in a 3- and 6-month weight loss regime for 60 overweight adult dogs in two different clinical settings. On average, the dogs in this summary lost 0.75% per week regardless of more aggressive rates set by the nutritionist. Accuracy in predicting future weights by the software was dependent upon the desired rate of weight loss selected, the equation used to estimate maintenance energy requirement, and owner compliance. Over time, accuracy in predicting future canine weights improved. All healthy, overweight or obese dogs summarized in these two studies did lose weight and reached an optimal or at least lower body condition score with the aid of this software program and diet.  相似文献   

Campylobacter   总被引：5，自引：0，他引：5  

Moore JE  Corcoran D  Dooley JS  Fanning S  Lucey B  Matsuda M  McDowell DA  Mégraud F  Millar BC  O'Mahony R  O'Riordan L  O'Rourke M  Rao JR  Rooney PJ  Sails A  Whyte P 《Veterinary research》2005,36(3):351-382

Species within the genus, Campylobacter, have emerged over the last three decades as significant clinical pathogens, particularly of human public health concern, where the majority of acute bacterial enteritis in the Western world is due to these organisms. Of particular concern are the species, C. jejuni and C. coli, which are responsible for most of these gastrointestinal-related infections. Although these organisms have already emerged as causative agents of zoonoses, several aspects of their epidemiology and pathophysiology are only beginning to emerge. Trends in increasing antibiotic resistance are beginning to emerge with oral antibiotics, which may be the drug of choice for when it is necessary to intervene chemotherapeutically. This review wishes to examine (i) emerging clinical aspects of the disease, such as Guillain Barre syndrome (GBS), (ii) the association between these organisms and poultry as a natural host, (iii) environmental aspects of Campylobacter epidemiology, (iv) the emergence of atypical campylobacters (v) emerging trends in antibiotic resistance, (vi) adoption of modern methods for the detection of campylobacters.  相似文献   

Host Specialization not Detected Among Isolates of the EC-1 Lineage of <Emphasis Type="Italic">Phytophthora infestans</Emphasis> Attacking Wild and Cultivated Potatoes in Peru     

Guillemette?Garry  Alberto?Salas  Gregory?A.?ForbesEmail author  Wilmer?Perez  Magnolia?Santa?Cruz  Rebecca?J.?Nelson 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(1):71-81

To determine whether populations of Phytophthora infestans attacking wild and cultivated potatoes in the highlands of Peru are specialized on their hosts of origin, we characterized isolates using several neutral markers, metalaxyl resistance and for aggressiveness in a detached leaf assay. One hundred and fifty-three isolates were collected from the northern and central highlands of Peru from different potato cultivars (both modern and native cultivars) and from different species of wild, tuber-bearing potatoes. All the isolates analyzed belonged to one of four clonal lineages that had been described previously in Peru: EC-1, US-1, PE-3 and PE-7. The EC-1 lineage (n = 133) was dominant and present in similar frequencies on wild and cultivated potatoes. PE-3 (n = 14) was found primarily on cultivated potatoes, with only one isolate coming from a wild host. US-1 (n = 2) and PE-7 (n = 4) were rare; all but one (PE-7) occurred on wild potatoes. Isolates from the EC-1 lineage from modern cultivars were compared in three separate detached leaf inoculation assays with EC-1 isolates from the wild potato species S. sogarandinum, S. bill-hookerii or S. huancabambense, respectively. No significant interactions between isolate type (from wild or cultivated potato) and host type (wild or cultivated) were measured for any assay. It appears that the pathogen genotypes in the EC-1 lineage indiscriminately attack both wild and cultivated tuber-bearing solanaceous hosts in Peru, and breeders should be able to select for resistance using the common EC-1 lineage.  相似文献   

Simulation of Potato Late Blight in the Andes. I: Modification and Parameterization of the LATEBLIGHT Model     

Andrade-Piedra JL  Hijmans RJ  Forbes GA  Fry WE  Nelson RJ 《Phytopathology》2005,95(10):1191-1199

ABSTRACT LATEBLIGHT, a mathematical model that simulates the effects of weather, host growth and resistance, and fungicide use on asexual development and growth of Phytophthora infestans on potato foliage, was modified so that it can be used in the Andes and, eventually, worldwide. The modifications included (i) the incorporation of improved equations for the effect of temperature on lesion growth rate (LGR) and sporulation rate (SR); (ii) the incorporation of temperature-dependent latent period (LP); and (iii) the use of experimentally measured parameters of LGR, SR, and LP for specific potato cultivars and pathogen lineages. The model was parameterized for three Peruvian potato cultivars (Tomasa, Yungay, and Amarilis) infected with isolates of a new clonal lineage of P. infestans that is currently predominant in Ecuador and Peru (EC-1).  相似文献   

Molecular characterization of potentially zoonotic isolates of Giardia duodenalis in horses     

Traub R  Wade S  Read C  Thompson A  Mohammed H 《Veterinary parasitology》2005,130(3-4):317-321

Giardia isolates from eight horses from New York State (NY), USA and two horses from Western Australia (WA) were genetically characterized at the SSU-rDNA and triose-phosphate isomerase (TPI) genes. Phylogenetic analysis of the TPI gene provided strong support for the placement of both isolates of Giardia from horses in WA and a single isolate from a horse in NY within the assemblage AI genotype of G. duodenalis. Another two isolates from horses in NY placed within the assemblage AII genotype of G. duodenalis. Phylogenetic analysis of the TPI gene also provided strong bootstrap support for the placement of four G. duodenalis isolates from horses in NY into a potentially host-specific sub-assemblage of assemblage BIV. The results of this study are consistent with previous studies showing that assemblages AI and AII of G. duodenalis provide the greatest potential zoonotic risk to humans. Horses may therefore constitute a potential source for human infection of Giardia either directly or via watersheds.  相似文献   

Light-microscopy evaluation of zonular fiber morphology in dogs with glaucoma: secondary to lens displacement   总被引：2，自引：0，他引：2  

Morris RA  Dubielzig RR 《Veterinary ophthalmology》2005,8(2):81-84

Lens displacement resulting in secondary glaucoma is common in terrier breeds. This study was carried out to evaluate whether light microscopy was useful in detecting abnormal patterns in zonular fiber protein. Eyes from 63 dogs with glaucoma secondary to lens displacement were evaluated for the presence of abnormal zonular fiber morphology using the following stains: hematoxylin and eosin, periodic acid Schiff (PAS), Masson's trichrome and Verhoeff's elastin stains. Two distinct forms of abnormal zonular fiber morphology were recognized and designated as zonular fiber dysplasia (ZFD) and zonular fiber collagenization (ZFC). ZFD protein morphology was characterized by being tightly adherent to the nonpigmented ciliary body epithelium, exhibiting a distinct lamellar and cross-hatched pattern and staining strongly positive with PAS and trichrome stains, and staining negative with elastin stains. ZFD was predominant in terrier breeds (18 of 29) and Shar-Pei dogs (4 of 29). ZFC abnormality was characterized by excessive zonular fiber that was not tightly adherent to the ciliary body epithelium and staining positive with PAS, trichrome (blue for collagen) and elastin stains. Only 7 of 19 dogs with ZFC changes were terrier breeds, and there was no pattern in the breeds affected. Fifteen of the 63 dogs used in the study had normal appearing zonular fibers. The staining pattern in these dogs matched normal controls by staining positive with PAS and Verhoeff's elastin stains and had only minimal positive staining with Masson's trichrome stain. Results suggest that light microscopy is useful in detecting breed-related changes in zonular fiber morphology in cases of glaucoma secondary to lens displacement. These changes may correlate with the presence of abnormal zonular fiber proteins and might be important in the pathogenesis of primary lens displacement in terrier and Shar-Pei dogs.  相似文献