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排序方式: 共有306条查询结果,搜索用时 15 毫秒
81.
Eva Syrová Miroslava Palíková Jan Mendel Veronika Seidlová Ivana Papežíková Heike Schmidt-Posthaus Kristina Somerlíková Hana Minářová Lukáš Mareš Ivana Mikulíková Jiří Pikula Jan Mareš 《Journal of fish diseases》2020,43(10):1201-1211
Tetracapsuloides bryosalmonae (Myxozoa: Malacosporea) is the causative agent of proliferative kidney disease (PKD), which affects both wild and farmed salmonid fish. The objective of this study was to outline differences in susceptibility to PKD in different salmonid species, hybrids and breeding lineages. Susceptibility to T. bryosalmonae infection was established based on cumulative mortality, pathological findings and detection of T. bryosalmonae in the kidney using immunohistochemistry and molecular methods. Determination of pure and hybrid individuals of different species in the genus Salvelinus, and dissimilarity of rainbow trout lineages, was performed using traditional polymerase chain reaction (PCR) and microsatellite analyses. Rainbow trout displayed higher disease severity compared with brook trout and Alsatian charr. Moreover, the results indicated differences in infection susceptibility, not only among different salmonid species but also among different lineages of charr and rainbow trout. Our study indicated that some salmonid species and even different lineages of the same species are more suitable for farming under PKD pressure. 相似文献
82.
Milder IE Arts IC Venema DP Lasaroms JJ Wähälä K Hollman PC 《Journal of agricultural and food chemistry》2004,52(15):4643-4651
A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of the four major enterolignan precursors [secoisolariciresinol, matairesinol, lariciresinol, and pinoresinol] in foods. The method consists of alkaline methanolic extraction, followed by enzymatic hydrolysis using Helix pomatia (H. pomatia) beta-glucuronidase/sulfatase. H. pomatia was selected from several enzymes based on its ability to hydrolyze isolated lignan glucosides. After ether extraction samples were analyzed and quantified against secoisolariciresinol-d8 and matairesinol-d6. The method was optimized using model products: broccoli, bread, flaxseed, and tea. The yield of methanolic extraction increased up to 81%, when it was combined with alkaline hydrolysis. Detection limits were 4-10 microg/(100 g dry weight) for solid foods and 0.2-0.4 microg/(100 mL) for beverages. Within- and between-run coefficients of variation were 6-21 and 6-33%, respectively. Recovery of lignans added to model products was satisfactory (73-123%), except for matairesinol added to bread (51-55%). 相似文献
83.
Prediction of the first occurrence of potato late blight (Phytophthora infestans) given by the SIMPHYT1 model, which has been used for about 20 years, has not been found satisfactory in years with high soil moisture. Consequently, a new model, SIMBLIGHT1, has been developed. As input parameters SIMBLIGHT1 requires temperature, relative humidity and information on soil moisture, crop prevalence and cultivar susceptibility. SIMBLIGHT1 calculates a cumulative risk index for several groups of emergence dates and signals the start of the epidemic once a given threshold is overridden. Model validation and comparison of SIMBLIGHT1 with SIMPHYT1 were performed with field data from 11 years. Results were promising and SIMBLIGHT1 gave better results than SIMPHYT1 when soils of potato fields were waterlogged. Efforts are currently being made to improve SIMBLIGHT1 and in the long term this model will replace SIMPHYT1. 相似文献
84.
Kristina M. Stanfield K. Nasir Khan Michael R. Gralinski 《Veterinary immunology and immunopathology》2001,80(3-4):309-314
Prostaglandins have diverse roles in the cardiovascular system mediating both physiologic and inflammatory responses. Two cyclooxygenase isoforms, cyclooxygenase-1 and cyclooxygenase-2, catalyze prostaglandin production. In many tissues and cell types studied, cyclooxygenase-1 is constitutively active whereas cyclooxygenase-2 expression is primarily responsible for prostaglandin production during inflammation. However, little information exists concerning which isoform is responsible for prostaglandin-mediated effects in the heart. We examined cyclooxygenase-1 and cyclooxygenase-2 expression in heart and vascular tissue of dogs using isoform-specific antibodies. In addition, tissues from dogs treated with naproxen (5–10 mg/kg/day), an inhibitor of prostaglandin production were also examined. Cyclooxygenase-1 expression was evident in endothelial cells of the microvasculature of the heart, aorta and renal artery. Cyclooxygenase-1 expression was also found in fibrocytes of the tricuspid valve and in the chordae tendinae. Animals treated with naproxen exhibited a similar pattern and intensity of cyclooxygenase-1 staining. No cyclooxygenase-2 expression was evident in cardiac tissue. However, minimal cyclooxygenase-2 immunoreactivity was present in the vascular endothelial cells of small myocardial blood vessels located in several regions of the heart as well as in endothelial cells of the aorta. These data may expand our understanding of the effects of non-steroidal anti-inflammatory drugs on cardiac function. 相似文献
85.
A heterologous RIA system was set up for measuring bovine, ovine and porcine calcitonin (CT). The system consisted of porcine GT used as standard and for the preparation of an iodinated tracer. The antiserum used was raised against ovine GT. For each analysis was used 25–200 µl blood plasma. Practical detection limit was 0.25 µg of CT per litre of blood plasma.The parallelism between the dose response curves for the p-GT standard and for the assay of increasing amounts of bovine, ovine and porcine blood plasma showed the suitability of the present assay system to study the GT secretion in these species. Furthermore, the reliability of the method was verified by a clearly recognized CT response to calcium infusion. 相似文献
86.
87.
Abnormal dark-adapted ERG in cats heterozygous for a recessively inherited rod-cone degeneration 总被引:1,自引:0,他引:1
Purpose To study retinal function in cats homozygous and heterozygous for a recessively inherited rod‐cone degeneration. Methods Dark‐adapted electroretinograms (ERGs) were performed on early affected, heterozygous (ophthalmoscopically normal), and clinically normal, nonrelated cats. Responses to blue stimuli over a 3.9‐log unit range were recorded. Results Lower b‐wave amplitudes than normal were observed in heterozygotes and early affected cats. The amplitudes of the heterozygotes took an intermediate position between normal and early affected cats. Normalized amplitude/intensity data suggest a normal dynamic range in carriers. B‐wave implicit times in carriers were comparable to those of normal cats. Conclusions These results show that heterozygotes have an altered retinal function, although they are ophthalmoscopically normal. It is difficult to electrophysiologically differentiate heterozygotes from affected cats with the very early stage of retinal degeneration. 相似文献
88.
Stewart Thompson Rebecca E. H. Whiting Randy H. Kardon Edwin M. Stone Kristina Narfstrm 《Veterinary ophthalmology》2010,13(3):151-157
Objective To understand how progressive rod cone degeneration due to a mutation in CEP290 affects the pupillary light reflex (PLR) in domestic cats. Animals studied Domestic cats identified as either normal wildtype (WT; n = 6), or homozygous for the rdAc mutation in CEP290 and having early stage retinal degeneration (stage 2, S2; n = 4), or advanced retinal degeneration (S4; n = 6). Methods The effect of light on pupil size was measured over a series of 10‐s pulses of white and chromatic light in cats lightly sedated with medetomidine. Results In WT cats, the PLR was characterized by a pronounced initial constriction that rapidly re‐dilated during the stimulus (pupil escape), to a stable or sustained constriction. There was then a marked constriction at stimulus offset. Each component of the PLR was retained in affected cats, but with progressively reduced irradiance sensitivity from early to advanced retinal disease. Conclusions The PLR of cats had multiple phases, with a remarkably high‐amplitude ‘paradoxical’ off‐constriction even in the absence of retinal disease. In rdAc cats, reduced irradiance sensitivity was consistent with progressive loss of rod and cone function. Based on previously characterized retinal pathology, this suggests the visual streak of the retina has a proportionally large contribution to PLR input. These findings support the hypothesis that the efficacy of planned therapeutic trials can be determined by careful evaluation of the PLR in cats. 相似文献
89.
对celB基因标记法检测苜蓿根瘤菌竞争性的可行性进行了研究。通过供体大肠杆菌HAMBI2356与根瘤菌接合的方法成功地将celB基因导入到4株苜蓿根瘤菌株Y611、BB1811、BB2211和WZ622中,然后对标记基因可能会对标记菌株产生的影响进行了一系列检测,结果表明标记基因在标记菌株内能稳定传代,而且对标记菌株的生长、竞争性及有效性都没有显著影响,从而证明celB基因标记技术可以作为一种简便、直观而又有效的检测手段用于追踪根瘤菌株在土壤中的竞争性。 相似文献
90.
Gu L Geders TW Wang B Gerwick WH Håkansson K Smith JL Sherman DH 《Science (New York, N.Y.)》2007,318(5852):970-974
An unexpected biochemical strategy for chain initiation is described for the loading module of the polyketide synthase of curacin A, an anticancer lead derived from the marine cyanobacterium Lyngbya majuscula. A central GCN5-related N-acetyltransferase (GNAT) domain bears bifunctional decarboxylase/S-acetyltransferase activity, both unprecedented for the GNAT superfamily. A CurA loading tridomain, consisting of an adaptor domain, the GNAT domain, and an acyl carrier protein, was assessed biochemically, revealing that a domain showing homology to GNAT (GNAT(L)) catalyzes (i) decarboxylation of malonyl-coenzyme A (malonyl-CoA) to acetyl-CoA and (ii) direct S-acetyl transfer from acetyl-CoA to load an adjacent acyl carrier protein domain (ACP(L)). Moreover, the N-terminal adapter domain was shown to facilitate acetyl-group transfer. Crystal structures of GNAT(L) were solved at 1.95 angstroms (ligand-free form) and 2.75 angstroms (acyl-CoA complex), showing distinct substrate tunnels for acyl-CoA and holo-ACP(L) binding. Modeling and site-directed mutagenesis experiments demonstrated that histidine-389 and threonine-355, at the convergence of the CoA and ACP tunnels, participate in malonyl-CoA decarboxylation but not in acetyl-group transfer. Decarboxylation precedes acetyl-group transfer, leading to acetyl-ACP(L) as the key curacin A starter unit. 相似文献