Optimization of extraction conditions for active components in Hypericum perforatum using response surface methodology     

Liu FF  Ang CY  Springer D 《Journal of agricultural and food chemistry》2000,48(8):3364-3371

Optimal conditions for extraction of Hypericum perforatum were determined using response surface methodology. A 3 x 4 x 4 full factorial design representing three extraction temperatures, four extraction times, and four solvent concentrations was executed. The overall extraction efficiency was defined by comparing either the total extractable material weight or the individual component peak area to the peak area of luteolin as internal standard. Of the tested variables, the extraction temperature most significantly affected extraction efficiency. Higher temperatures gave better extraction efficiencies, but high temperature also caused decomposition of hypericin. Within the test range, responses for most variables had local maxima. Optimum ranges of time and concentration for individual variables were overlaid. Considering all variables, optimum ranges for extraction time and extraction solvent concentration (percent ethanol in acetone) were 5.0-6.7 h and 44-74% at 23 degrees C, 5.4-6.9 h and 45-72% at 40 degrees C, and 5.3-5.9 h and 44-69% ethanol in acetone at 55 degrees C, respectively.  相似文献   

Biochemistry. Ligand chip helps manipulate cells     

Bhattacharjee Y 《Science (New York, N.Y.)》2000,290(5496):1477-1478

Scientists at the University of Chicago have found an electrochemical way to control interactions between cells and a chip. It's an improvement over existing methods of influencing cell behavior, none of which allows control over cell-surface activities with chip-bound molecules. Researchers say the achievement could be a key step toward a wide variety of applications--everything from new drug assays to prosthetic aids that replace damaged neurons.  相似文献   

Hypolipemia associated with the wasting condition of rabbits infected with Strongyloides papillosus     

Nakamura Y  Motokawa M 《Veterinary parasitology》2000,88(1-2):147-151

Rabbits develop a wasting condition in the intestinal stage of Strongyloides papillosus infection. Serum inflammatory cytokine and lipid profiles were investigated in five rabbits infected with S. papillosus and five uninfected pair-fed controls to ascertain whether the disease is inflammatory cytokine-mediated cachexia. Tumor necrosis factor alpha (TNF alpha) was detected in one infected animal at Day 7 after infection. Interleukin (IL)-1 was detected in three infected, and one control, animals at Day 28. IL-6 remained unchanged in both the groups. Infected animals developed hypolipemia, including hypotriglyceridemia in the intestinal stage of infection. Control animals lost body weight in the same manner as the infected animals, but had elevated cholesterols and phospholipids with normal triglyceride concentrations. The results suggested that the wasting condition has no association with cachexia induced by TNF alpha. IL-1 or IL-6, and that hepatic function for lipid synthesis is affected during the intestinal stage of S. papillosus infection.  相似文献   

Ocular Onchocerca infections in two dogs in western United States     

Eberhard ML  Ortega Y  Dial S  Schiller CA  Sears AW  Greiner E 《Veterinary parasitology》2000,90(4):333-338

Two dogs, one from California and one from Arizona, were found to have aberrant infections caused by filarial nematodes of the genus Onchocerca. In both cases, the parasites are localized in or near the eye. In one case the worm was located in the cornea and was surgically removed. In the second case, a very marked granulomatous reaction was induced in the retrobulbar space, mimicking an abscess. This eye was enucleated. The worms in both instances were female, and were gravid, i.e. contained microfilariae in utero, indicating that a male worm(s) had been present and mating had occurred. The exact identity of the species of Onchocerca responsible cannot be determined, although the features observed are most like Onchocerca lienalis of cattle. These cases represent the fourth and fifth such cases reported from the US, and are especially interesting because of the unusual location of the worms, the small number of recognized cases, and the similarity to a recent zoonotic human infection.  相似文献   

A pleomorphic adenoma of the lacrimal gland in a dog   总被引：1，自引：0，他引：1  

Hirayama K  Kagawa Y  Tsuzuki K  Kotani T  Azuma Y  Yoshino T  Taniyama H 《Veterinary pathology》2000,37(4):353-356

A 13-year-old female mongrel dog had a pleomorphic adenoma of the lacrimal gland in the right upper orbit. The tumor measured 3.8 x 3.0 x 3.3 cm, appeared white, round, and firm, and pressed the right globe and surrounding tissues. Histopathologically, the tumor had a thin connective tissue capsule and was composed of tubules with two cell types, some resembling luminal epithelial cells making up the tubular structures and the other of myoepithelial cells. Epithelial tubules were disposed in an adenomatous fashion and separated from each other by proliferating pleomorphic myoepithelial cells. Immunohistochemically, large numbers of the luminal epithelial cells revealed an immunopositive reaction against keratin/cytokeratin (AE1/AE3), and some epithelial cells reacted against cytokeratin 14. Spindle-shaped myoepithelial cells revealed an immunopositive reaction against cytokeratin 14, alpha-smooth muscle actin, and vimentin. A small number of myoepithelial cells reacted against desmin. S-100 protein immunopositivity was frequently found in luminal epithelial cells and rarely in the pleomorphic myoepithelial cells. Glial fibrillary acidic protein positivity was commonly found in myoepithelial cells, myxoid matrices, and intracystic materials, but not in luminal epithelial cells.  相似文献   

Genetic typing of classical swine fever virus   总被引：18，自引：0，他引：18  

Paton DJ  McGoldrick A  Greiser-Wilke I  Parchariyanon S  Song JY  Liou PP  Stadejek T  Lowings JP  Björklund H  Belák S 《Veterinary microbiology》2000,73(2-3):137-157

Three regions of the classical swine fever virus (CSFV) genome that have been widely sequenced were compared with respect to their ability to discriminate between isolates and to segregate viruses into genetic groups. Sequence data-sets were assembled for 55 CSFVs comprising 150 nucleotides of the 5' non-translated region, 190 nucleotides of the E2 envelope glycoprotein gene and 409 nucleotides of the NS5B polymerase gene. Phylogenetic analysis of each data-set revealed similar groups and subgroups. For closely related viruses, the more variable or larger data-sets gave better discrimination, and the most reliable classification was obtained with sequence data from the NS5B region. No evidence was found for intertypic recombination between CSFVs. A larger data-set was also analysed comprising 190 nucleotides of E2 sequence from 100 CSFVs from different parts of the world, in order to assess the extent and global distribution of CSFV diversity. Additional groups of CSFV are evident from Asia and the nomenclature of Lowings et al. (1996) [Lowings, P., Ibata, G., Needham, J., Paton, D., 1996. J. Gen. Virol. 77, 1311-1321] needs to be updated to accommodate these. A tentative assignment, adapting rather than overturning the previous nomenclature divides CSF viruses into three groups with three or four subgroups: 1.1, 1.2, 1.3; 2.1, 2.2, 2.3; 3.1, 3.2, 3.3, 3.4. The expanding data-base of CSFV sequences should improve the prospects of disease tracing in the future, and provide a basis for a standardised approach to ensure that results from different laboratories are comparable.  相似文献   

Antimicrobial susceptibility and presence of resistance genes in staphylococci from poultry     

Aarestrup FM  AgersŁ Y  Ahrens P  JŁrgensen JC  Madsen M  Jensen LB 《Veterinary microbiology》2000,74(4):353-364

The species distribution, susceptibility to 19 antimicrobial agents and presence of selected genes encoding resistance to macrolides, streptogramins and tetracyclines were examined among 118 staphylococcal isolates from infections of poultry in Denmark. Isolates were identified using a combination of conventional biochemical testing and 16S rDNA sequencing. The most common species were Staphylococcus aureus (83), Staphylococcus hyicus (11), Staphylococcus xylosus (9) and Staphylococcus cohnii (6). The isolates were susceptible to most antimicrobials tested. A high frequency of S. aureus (30%) was resistant to ciprofloxacin. Only six (7%) S. aureus isolates and one Staphylococcus saprophyticus were penicillin resistant. Resistance to sulphamethoxazole was observed among 16 (19%) of S. aureus isolates and two coagulase negative staphylococci (CNS). Twenty (24%) of the S. aureus isolates were resistant to erythromycin and 19 of these isolates contained the ermA gene, whereas the remaining isolate contained the ermC gene. Eleven (48%) of the novobiocin resistant CNS were resistant to erythromycin and all these isolates contained the ermA gene. Two isolates identified as S. xylosus, were found to be resistant to streptogramins and both contained the vatB- and the vgaB-genes. Thirty-nine (47%) of the S. aureus isolates, three of nine S. hyicus and eight of the 23 novobiocin resistant CNS were tetracycline resistant and all contained the tet(K) gene. A single S. aureus isolate also contained the tet(M) gene. The present study showed a frequent occurrence of resistance to fluoroquinolones, tetracycline and macrolides among staphylococci isolated from broilers in Denmark, whereas the occurrence of resistance to other antimicrobial agents remains low. Similar genes, encoding resistance to erythromycin, tetracycline and streptogramins to those previously observed, were detected.  相似文献   

Pathogenicity of Rhodococcus equi expressing a virulence-associated 20 kDa protein (VapB) in foals     

Takai S  Anzai T  Fujita Y  Akita O  Shoda M  Tsubaki S  Wada R 《Veterinary microbiology》2000,76(1):71-80

Rhodococcus equi strains of intermediate virulence (IMV) for mice possess a 20kDa protein designated Virulence Associated Protein B (VapB) and a virulence plasmid of 79-100kb, and can be recovered from the submaxillary lymph nodes of pigs. The pathogenicity of such R. equi strains for foals is unknown. In this study, two foals, 42 and 43 days of age, were infected intratracheally with 10(6) and 10(9) cells of R. equi IMV strain A5, respectively. The foal infected with 10(9) cells of strain A5 became clinically ill, with the onset of illness (pyrexia and depression) occurring 21 days after inoculation. R. equi was isolated from the feces and tracheal washings of the foal from 14 to 28 days after inoculation. The foal infected with 10(6) cells of A5 showed no clinical signs, and no R. equi was isolated from any of the samples of feces or tracheal washings during the 28 days of observation. Two foals of 45 and 50 days of age were infected with 10(5) or 10(6) of virulent R. equi ATCC 33701 having 15-17kDa surface proteins designated VapA. Both exhibited severe clinical signs (pyrexia, depression and anorexia) at 12 and 13 days after inoculation. Histopathological examination revealed that strain A5 caused focal granulomatous pneumonia in the foals. R. equi IMV strain A5 was isolated from lung lesions of both foals and from the contents of the intestinal tracts of the foal infected with 10(9) bacteria. These results suggest that IMV R. equi having VapB is less virulent than virulent R. equi having VapA in foals. This finding supports our previous results on the pathogenicities of R. equi strains having these virulence-associated antigens assessed by mouse pathogenicity tests.  相似文献   

Immunological characterization of the major outer membrane protein of Haemophilus somnus     

Tagawa Y  Bastida-Corcuera F  Corbeil LB 《Veterinary microbiology》2000,71(3-4):245-254

Antigens and molecular mass diversity of the Haemophilus somnus major outer membrane protein (MOMP) were investigated. The molecular mass of the MOMP of 53 strains of H. somnus varied from 43 to 33 kDa and four MOMP MAb reactivity patterns were detected in immunoblot analysis and immunodot assay. The molecular mass and MAb reactivity data were used for preliminary grouping of H. somnus strains. Disease strains fell into groups 1 and 3, including two of three Group 3 subgroups, whereas strains from asymptomatic carriers were found in all the four groups and three subgroups. Immunoblot analysis with convalescent phase serum showed strain specific reactivity with MOMPs from three isolates used to reproduce disease in cattle. The reaction with the MOMP was only detectable at dilutions of 1:100 or less, whereas the same convalescent sera showed strong reactivity at dilutions of 1:1000 (or more) with other H. somnus antigens. The data suggest that the bovine immune response to the MOMP during infection is weak and is directed to antigenically variable determinants in a strain-specific manner. This may be important in evaluating the role of the antibody response to MOMPs in protective immunity.  相似文献   

Antibody response to toxic shock syndrome toxin-1 of Staphylococcus aureus in dairy cows     

Hayakawa Y  Akagi M  Hayashi M  Shimano T  Komae H  Funaki O  Kaidoh T  Takeuchi S 《Veterinary microbiology》2000,72(3-4):321-327

Antibody response to toxic shock syndrome toxin-1 (TSST-1) of Staphylococcus aureus in dairy cows was examined by enzyme linked immunosorbent assay (ELISA). Serum antibody to TSST-1 was not detected in 39 (76.5%) of 51 calves, which were 1-6 months of age. In contrast, TSST-1 antibody was demonstrated in 1728 (72.6%) of 2380 lactating cows housed on 36 dairy farms. The ELISA values of antibody ranged from 0.2 to 3.0 OD and presented a distribution with the peak at 1.6 OD. The mean ELISA value differed between farms, and it increased slightly along with parturient history. Somatic cell counts of milk from 174 lactating cows was compared with TSST-1 antibody and tst1,000,000 cells per ml. The mean ELISA values in milk were lower than those of sera, but they rose as somatic cells increased. The tst gene of S. aureus detected in 76.0-86.2% of the milk samples containing somatic cells > 500,000 cells per ml, a level which indicates mastitis. The data suggests that many lactating cows may be infected by TSST-1- producing S. aureus.  相似文献