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1.
A frozen stabilate was produced from Theileria cervi sporozoites in salivary glands of adult Amblyomma americanum. The stabilate was inoculated into three fallow deer (Cervus dama) and two white-tailed deer (Odocoileus virginianus). Following inoculation, the white-tailed deer developed parasitemias as determined by blood smear examination at 11 and 13 days postexposure. Repeat examination of blood from the three fallow deer for 30 days postexposure failed to reveal observable piro-plasms. These findings indicate that fallow deer are not as susceptible to the Theileria cervi found in white-tailed deer from North America. Thus, there are some questions regarding the taxonomic position of this organism. 相似文献
2.
Laboratory reared Ixodes scapularis proved to be an efficient vector of Babesia odocoilei Emerson and Wright between white-tailed deer (Odocoileus virginianus). Transtadial survival of the babesia occurred between nymph and adult stages of the tick, and the adult stage transmitted the babesia. 相似文献
3.
On the production,elemental composition (C,N, P) and distribution of photosynthetic organic matter in the Southern Black Sea 总被引:2,自引:1,他引:1
Yılmaz Ayşen Tuğrul Süleyman Polat Çolpan Ediger Dilek Çoban Yeşim Morkoç Enis 《Hydrobiologia》1997,363(1-3):141-155
Chemical oceanographic understanding of the southernBlack Sea has been improved by recent measurements ofthe optical transparency,
phytoplankton biomass (interms of chlorophyll-a and particulate organic matter)and primary productivity. During the spring-autmunperiod
of 1995–1996, light generally penetrated onlyinto the upper 15–40 m, with an attenuation coefficientvarying between 0.125
and 0.350 m2122;1. The averagechlorophyll-a (Chl-a) concentrations for the euphoticzone ranged from 0.1 to 1.5 μg l2122;1. Coherentsub-surface Chl-a maxima were formed near the base ofthe euphotic zone only in summer. Production rate variedbetween
247 and 1925 in the spring and between 405 and687 mgC m2122;2 d2122;1 in the summer-autumn period.The average POM concentrations in the euphotic zonevaried regionally and seasonally between 3.8
and28.6 μm for POC, 0.5 and 3.1 μm for PON and0.02 and 0.1 μm for PP. Atomic ratios of C/N, C/Pand N/P, derived from the regressions
of POM data,ranged between 7.5 and 9.6, 109 and 165, and 11.2 and16.6, respectively. In the suboxic/anoxic interface,the elemental
ratios change substantially due to anaccumulation of PP cohering to Fe and Mn oxides. Thechemocline boundaries and the distinct
chemicalfeatures of the oxic/anoxic transition layer (the so-called suboxic zone) are all located at specificdensity surfaces;
however, they exhibit remarkablespatial and temporal variations both in their positionand in their magnitude, which permit
the definition of long-term changes in the biochemical properties of theBlack Sea upper layer.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Cultured human fetal aortic smooth muscle cells derived from the abdominal aorta converted benzo[a]pyrene (BaP) and 7,12-dimethylbenz[a]anthracene (DMBA) cytochrome P-450-dependent monooxygenation to metabolites detectable by both a highly sensitive radiometric assay and high pressure liquid chromatography (HPLC). Cells incubated with 3H-BaP transformed this substrate primarily to phenols. 14C-DMBA was converted to metabolites that cochromatographed with 12-hydroxymethyl-7-methylbenz[a]anthracene, 7-hydroxymethyl-12-methylbenz-[a]anthracene, 7,12-dihydroxymethylbenz[a]anthracene, and trans-8,9-dihydrodiol-7,12-DMBA. Exposure of cells in culture to 13 μM 1,2-benz[a]anthracene resulted in increased oxidative metabolism of both BaP and DMBA. In the case of BaP, total phenol formation was increased, while with DMBA all metabilities detected by HPLC were increased. Support for the potential role of metabolism of polycyclic aromatic hydrocarbons by aortic smooth muscle cells in the etiology of atherosclerosis was obtained. 相似文献
5.
Postmortem examination of a captive-bred American kestrel (Falco sparverius) showed numerous white necrotic foci 1-2 mm in diameter throughout the liver and spleen. The results of light and spleen. The results of light and electron microscopic studies and experimental transmission to a captive American kestrel and a barred owl (Strix varia) suggests a herpesvirus similar to those dsecribed for owls and other falcons in the U.S. This is the first report of a naturally occurring case of inclusion body disease of falcons in the American kestrel. 相似文献
6.
Blood samples were obtained from canvasback ducklings from Manitoba and Saskatchewan and from immature and adult canvasbacks on the Mississippi River near LaCrosse, Wisconsin and the Chesapeake Bay. These samples were used to determine baseline data on red cell counts, hematocrit, total protein, glucose, cholesterol, hemaglobin and distribution of plasma proteins. Calculations were also made to determine mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The major differences noted were between ducklings and adults. The former having higher total protein and lower hematocrit, glucose and cholesterol values. These hematologic values were collected in order to provide baseline information on apparently healthy canvasbacks, thereby providing disease investigators with a standard of comparison. 相似文献
7.
Several wild species of birds, including starlings (Sturnus vulgaris), house sparrows (Passer domesticus) and pigeons (Columba livia) gained access to an aviary housing Rothchild's mynahs (Leucospar rothchildii) and over 100 additional birds representing a variety of species. Six of approximately 15 mynahs became infected with avian pox and all of them died. None of the other birds in the aviary developed lesions. Pox virus was isolated from mynah facial lesions on chicken chorioallantoic membrane and in duck embryo fibroblast cell culture. It did not produce lesions in white Leghorn chickens, but did produce lesions in 4 of 11 wild starlings captured outside the aviary. Results indicated the agent was an indigenous starling pox capable of infecting and producing disease in mynah birds. Destruction of the captive starlings and isolation of the remaining mynahs immediately stopped the mortality. 相似文献
8.
Dane D. Jensen Cody B. Godfrey Christian Niklas Meritxell Canals Martina Kocan Daniel P. Poole Jane E. Murphy Farzad Alemi Graeme S. Cottrell Christoph Korbmacher Nevin A. Lambert Nigel W. Bunnett Carlos U. Corvera 《The Journal of biological chemistry》2013,288(32):22942-22960
TGR5 is a G protein-coupled receptor that mediates bile acid (BA) effects on energy balance, inflammation, digestion, and sensation. The mechanisms and spatiotemporal control of TGR5 signaling are poorly understood. We investigated TGR5 signaling and trafficking in transfected HEK293 cells and colonocytes (NCM460) that endogenously express TGR5. BAs (deoxycholic acid (DCA), taurolithocholic acid) and the selective agonists oleanolic acid and 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated cAMP formation but did not induce TGR5 endocytosis or recruitment of β-arrestins, as assessed by confocal microscopy. DCA, taurolithocholic acid, and oleanolic acid did not stimulate TGR5 association with β-arrestin 1/2 or G protein-coupled receptor kinase (GRK) 2/5/6, as determined by bioluminescence resonance energy transfer. 3-(2-chlorophenyl)-N-(4-chlorophenyl)-N, 5-dimethylisoxazole-4-carboxamide stimulated a low level of TGR5 interaction with β-arrestin 2 and GRK2. DCA induced cAMP formation at the plasma membrane and cytosol, as determined using exchange factor directly regulated by cAMP (Epac2)-based reporters, but cAMP signals did not desensitize. AG1478, an inhibitor of epidermal growth factor receptor tyrosine kinase, the metalloprotease inhibitor batimastat, and methyl-β-cyclodextrin and filipin, which block lipid raft formation, prevented DCA stimulation of ERK1/2. Bioluminescence resonance energy transfer analysis revealed TGR5 and EGFR interactions that were blocked by disruption of lipid rafts. DCA stimulated TGR5 redistribution to plasma membrane microdomains, as localized by immunogold electron microscopy. Thus, TGR5 does not interact with β-arrestins, desensitize, or traffic to endosomes. TGR5 signals from plasma membrane rafts that facilitate EGFR interaction and transactivation. An understanding of the spatiotemporal control of TGR5 signaling provides insights into the actions of BAs and therapeutic TGR5 agonists/antagonists. 相似文献
9.
An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) as a potential industrial biocatalyst
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Zorica D. Knežević‐Jugović Milena G. Žuža Sonja M. Jakovetić Andrea B. Stefanović Enis S. Džunuzović Katarina B. Jeremić Slobodan M. Jovanović 《Biotechnology progress》2016,32(1):43-53
The use of penicillin G acylase (PGA) covalently linked to insoluble carrier is expected to produce major advances in pharmaceutical processing industry and the enzyme stability enhancement is still a significant challenge. The objective of this study was to improve catalytic performance of the covalently immobilized PGA on a potential industrial carrier, macroporous poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) [poly(GMA‐co‐EGDMA)], by optimizing the copolymerization process and the enzyme attachment procedure. This synthetic copolymer could be a very promising alternative for the development of low‐cost, easy‐to‐prepare, and stable biocatalyst compared to expensive commercially available epoxy carriers such as Eupergit or Sepabeads. The PGA immobilized on poly(GMA‐co‐EGDMA) in the shape of microbeads obtained by suspension copolymerization appeared to have higher activity yield compared to copolymerization in a cast. Optimal conditions for the immobilization of PGA on poly(GMA‐co‐EGDMA) microbeads were 1 mg/mL of PGA in 0.75 mol/L phosphate buffer pH 6.0 at 25°C for 24 h, leading to the active biocatalyst with the specific activity of 252.7 U/g dry beads. Chemical amination of the immobilized PGA could contribute to the enhanced stability of the biocatalyst by inducing secondary interactions between the enzyme and the carrier, ensuring multipoint attachment. The best balance between the activity yield (51.5%), enzyme loading (25.6 mg/g), and stability (stabilization factor 22.2) was achieved for the partially modified PGA. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:43–53, 2016 相似文献
10.
De La Fuente J Golsteyn Thomas EJ van den Bussche RA Hamilton RG Tanaka EE Druhan SE Kocan KM 《Applied and environmental microbiology》2003,69(8):5001-5005
Anaplasma marginale (Rickettsiales: Anaplasmataceae), a tick-borne pathogen of cattle, is endemic in tropical and subtropical regions of the world. Although serologic tests have identified American bison, Bison bison, as being infected with A. marginale, the present study was undertaken to confirm A. marginale infection and to characterize isolates obtained from naturally infected bison in the United States and Canada. Major surface protein (MSP1a and MSP4) sequences of bison isolates were characterized in comparison with New World cattle isolates. Blood from one U.S. bison was inoculated into a susceptible, splenectomized calf, which developed acute anaplasmosis, demonstrating infectivity of this A. marginale bison isolate for cattle. The results of this study showed that these A. marginale isolates obtained from bison were similar to ones from naturally infected cattle. 相似文献