Partial purification and characterisation of the proteolytic enzymes of Fasciola gigantica adult worms.     

Benjamin O. Fagbemi  George V. Hillyer 《Veterinary parasitology》1991,40(3-4):217-226

The proteases of adult Fasciola gigantica whole worm were analysed by preparative isoelectric focusing and by gelatin-substrate gel electrophoresis at acidic and neutral pH (4.5 and 7.0). At least 15 bands of proteases were observed. These proteases had molecular weights ranging from 26 to 193 kDa and isoelectric points of 4.92–7.63. Potease-rich fractions were subsequently separated from whole worm preparation of the parasite by filtration in Sephacryl S-200. The proteases were able to digest bovine immunoglobulin G (IgG) and globin (derived from bovine haemoglobin) in vitro. The sizes of the proteases in these fractions were from 26 to 96 kDa, and they were inhibited by the protease inhibitors phenylmethylsulphonyl fluoride (PMSF), leupeptin and trasylol.  相似文献   

Enhancement of infectious bovine keratoconjunctivitis by modified-live infectious bovine rhinotracheitis virus vaccine   总被引：1，自引：0，他引：1  

L W George  A Ardans  J Mihalyi  M R Guerra 《American journal of veterinary research》1988,49(11):1800-1806

The effects of a modified-live infectious bovine rhinotracheitis virus vaccine (administered ocularly or intranasally) on experimentally induced infectious bovine keratoconjunctivitis were evaluated. The modified-live infectious bovine rhinotracheitis virus vaccine was administered to 13 male Holstein calves (intranasally in 4 and ocularly in 9; day 0). Five calves were not vaccinated and served as controls. Calves were examined daily and, starting on day 4, Moraxella bovis was administered ocularly to all 18 calves once daily for 4 days. The eyes of all calves were assigned a clinical score, and the ocular secretions were evaluated for presence of infectious bovine rhinotracheitis virus and M bovis daily until day 19. The severity of the ocular lesions was estimated by scoring the lesions clinically and by determining the protein concentration, myeloperoxidase activity, and WBC count in the tears. By day 5, conjunctivitis, chemosis, and epiphora were observed in all of the calves vaccinated ocularly. The calves vaccinated intranasally developed conjunctival plaques, but did not develop chemosis or photophobia. All of the calves developed keratitis after inoculation with M bovis. The median lesion scores were greater in both groups of vaccinated calves than in the controls. Corneal perforations developed exclusively in the vaccinated calves. The frequency of M bovis isolation from ocular secretions was significantly (P less than 0.05) greater in the vaccinated calves than in the controls. The tears from the intranasally vaccinated calves contained the highest myeloperoxidase activity and WBC count. The mean protein concentration in the tears of vaccinated calves was not significantly different from that in tears of controls.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Interaction of acute feline herpesvirus-1 and chronic feline immunodeficiency virus infections in experimentally infected specific pathogen free cats.     

G H Reubel  J W George  J E Barlough  J Higgins  C K Grant  N C Pedersen 《Veterinary immunology and immunopathology》1992,35(1-2):95-119

Cats with or without chronic feline immunodeficiency virus (FIV) infection were exposed to feline herpesvirus, type 1 (FHV-1). FIV infected cats became sicker than non-FIV infected cats and required more supportive treatment. However, there were no differences in the length of their illness or in the levels and duration of FHV-1 shedding. FHV-1 infection caused a transient neutrophilia at Day 7 with a rapid return to preinfection levels. The neutrophilia coincided with a transient lymphopenia that was accompanied by a decline in both CD4+ and CD8+ T-lymphocytes. A brief decrease in the CD4+/CD8+ T-lymphocyte ratio occurred at Day 14 in both FIV infected and non-infected cats. This decrease was mainly the result of an absolute and transient increase in CD8+ T-lymphocytes. CD4+ and CD8+ T-lymphocyte numbers and CD4+/CD8+ T-lymphocyte ratios returned to baseline within 4-8 weeks in both FIV infected and non-infected cats. FIV infected cats produced less FHV-1 neutralizing antibodies during the first 3 weeks of infection than non-FIV infected animals. The IgM FHV-1 antibody response was depressed in FIV infected cats whereas the IgG antibody response was unaffected. FHV-1 infection evoked a comparable transient loss of lymphocyte blastogenic responses to concanavalin A and pokeweed mitogen in both FIV infected and non-infected cats. However, response to pokeweed mitogen took longer to return to normal in FIV infected animals. Lymphocytes from FIV infected cats had a greater and more sustained proliferative response to FHV-1 antigen than non-FIV infected cats. The ongoing IgG antibody response to FIV was not affected by FHV-1 infection.  相似文献   

Dry ashing method for the determination of total arsenic in animal tissues: collaborative study     

G M George  L J Frahm  J P McDonnell 《Journal of the Association of Official Analytical Chemists》1973,56(4):793-797

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How behavioural studies contribute to the species problem: a piscine perspective     

George W Barlow 《Fish and Fisheries》2002,3(3):197-212

During the ascendency of ethology, the study of animal behaviour contributed to taxonomic and phyletic issues, but the approach faded in parallel with the waning of systematic studies in general. Systematics and particularly phylogeny has experienced a resurgence with the advent of molecular tools. The understanding of behavioural evolution has benefited from molecular phylogenies. Behaviour's reciprocal contribution, however, currently lies chiefly in resolving the validity of species designation of allopatric species and in potentially helping in the overall classification of species. I review and evaluate the experimental methods favoured in seeking behavioural isolating mechanisms, and the challenge to the species concept when gene trees and species trees disagree. The dynamic situation in the Great Lakes of Africa offers under‐exploited opportunities to test whether behavioural isolating mechanisms evolve in the absence of secondary contact. Given that behaviour is more immediately responsive to changes in the physical and biological environment, behaviour may be the single most salient adaptive feature in speciation events. The species concept is viewed as a fuzzy but nonetheless useful set.  相似文献   

Growth and carcass characteristics of cull cows after different times-on-feed   总被引：1，自引：0，他引：1  

R J Matulis  F K McKeith  D B Faulkner  L L Berger  P George 《Journal of animal science》1987,65(3):669-674

Cull cows (N = 48) of similar age from Angus and Hereford breed types were assigned to one of four feeding periods (0, 28, 56 or 84 d) and subdivided into two groups, one implanted with Synovex-H and a non-implanted control. Cows were fed a high energy diet and slaughtered at the end of each feeding period. Average daily gain and feed efficiency were evaluated on each animal during the trial. The following carcass traits were evaluated: USDA yield and quality grade characteristics, boning yield, muscle weights, bone weights, pH and Warner-Bratzler shear force of the longissimus muscle. The left side of each carcass was boned and proximate analysis was determined. No significant implant effects were encountered for any of the traits evaluated; therefore, data were pooled and evaluated by feeding period only. Carcass weight and boneless forequarter and hindquarter tissue weights increased significantly between each feeding period; percent kidney, pelvic and heart fat (KPH) and yield grade did not differ (P greater than .05) until d 56 and 84, respectively. Quality grade and marbling scores improved (P less than .05) between 28 and 56 d of feeding. Biceps femoris weight changed during the 84-d experiment from 4.1 kg on d 0 to 5.3 kg on d 84 (P less than .05). Proximate analysis of the boneless tissue indicated an increase (P less than .05) in extractable fat of approximately 6% for each feeding period (6.3% fat on d 0 to 25.4% on d 84).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Coding/decoding and reversibility of droplet trains in microfluidic networks     

Fuerstman MJ  Garstecki P  Whitesides GM 《Science (New York, N.Y.)》2007,315(5813):828-832

Droplets of one liquid suspended in a second, immiscible liquid move through a microfluidic device in which a channel splits into two branches that reconnect downstream. The droplets choose a path based on the number of droplets that occupy each branch. The interaction among droplets in the channels results in complex sequences of path selection. The linearity of the flow through the microchannels, however, ensures that the behavior of the system can be reversed. This reversibility makes it possible to encrypt and decrypt signals coded in the intervals between droplets. The encoding/decoding device is a functional microfluidic system that requires droplets to navigate a network in a precise manner without the use of valves, switches, or other means of external control.  相似文献   

PDGFRA activating mutations in gastrointestinal stromal tumors     

Heinrich MC  Corless CL  Duensing A  McGreevey L  Chen CJ  Joseph N  Singer S  Griffith DJ  Haley A  Town A  Demetri GD  Fletcher CD  Fletcher JA 《Science (New York, N.Y.)》2003,299(5607):708-710

Most gastrointestinal stromal tumors (GISTs) have activating mutations in the KIT receptor tyrosine kinase, and most patients with GISTs respond well to Gleevec, which inhibits KIT kinase activity. Here we show that approximately 35% (14 of 40) of GISTs lacking KIT mutations have intragenic activation mutations in the related receptor tyrosine kinase, platelet-derived growth factor receptor alpha (PDGFRA). Tumors expressing KIT or PDGFRA oncoproteins were indistinguishable with respect to activation of downstream signaling intermediates and cytogenetic changes associated with tumor progression. Thus, KIT and PDGFRA mutations appear to be alternative and mutually exclusive oncogenic mechanisms in GISTs.  相似文献   

Watching a protein as it functions with 150-ps time-resolved x-ray crystallography     

Schotte F  Lim M  Jackson TA  Smirnov AV  Soman J  Olson JS  Phillips GN  Wulff M  Anfinrud PA 《Science (New York, N.Y.)》2003,300(5627):1944-1947

We report picosecond time-resolved x-ray diffraction from the myoglobin (Mb) mutant in which Leu29 is replaced by Phe (L29Fmutant). The frame-by-frame structural evolution, resolved to 1.8 angstroms, allows one to literally "watch" the protein as it executes its function. Time-resolved mid-infrared spectroscopy of flash-photolyzed L29F MbCO revealed a short-lived CO intermediate whose 140-ps lifetime is shorter than that found in wild-type protein by a factor of 1000. The electron density maps of the protein unveil transient conformational changes far more dramatic than the structural differences between the carboxy and deoxy states and depict the correlated side-chain motion responsible for rapidly sweeping CO away from its primary docking site.  相似文献   

Ethics. The ISSCR guidelines for human embryonic stem cell research     

Daley GQ  Ahrlund Richter L  Auerbach JM  Benvenisty N  Charo RA  Chen G  Deng HK  Goldstein LS  Hudson KL  Hyun I  Junn SC  Love J  Lee EH  McLaren A  Mummery CL  Nakatsuji N  Racowsky C  Rooke H  Rossant J  Schöler HR  Solbakk JH  Taylor P  Trounson AO  Weissman IL  Wilmut I  Yu J  Zoloth L 《Science (New York, N.Y.)》2007,315(5812):603-604

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