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1.
A total of 595 faecal samples from raptorial birds, either captive or free-living, residing in GREFA Wildlife Hospital were bacteriologically examined using various selective media and an Automated Diagnostic Assay System for Salmonella detection. Serotype and phage type of the strains identified as Salmonella was determined. In the captive group, of the 285 samples examined, 21 (7.36%) were positive for Salmonella. Serotyping revealed that most of the individuals were infected by Salmonella serotype Havana. This result suggested that there could be a source of contamination in the Hospital although it could not be established. In the wild free-living group, over 310 samples examined (4.19%) were positive for Salmonella. The Salmonella isolates showed a major variety of serotypes: Enteritidis, Adelaide, Brandenburg, Newport, Typhimurium, Hadar, Saintpaul and Virchow. Most of them are similar to those commonly described in isolates from human and domestic animals. These results indicate that wild birds could be involved in the dissemination of Salmonella in humans or domestic animals or vice versa.  相似文献   
2.
采用世界先进的切向流超滤浓缩技术,对禽流感病毒(H9N2亚型)超滤浓缩成倍体积,测定血凝价HA和半数感染量EID50。结果HA成倍增加,废液HA呈阴性,病毒回收率达100%;受宿主鸡胚系统的影响,EID50与病毒量之间不是简单的直线关系,但病毒的活性不受影响。结果表明,所用超滤系统适用于禽流感病毒抗原的浓缩。  相似文献   
3.
In this paper, the use of supercritical fluid extraction (SFE) and micellar electrokinetic capillary chromatography (MEKC) is proposed for the complete analysis of volatile nitrosamines in sausages. The extraction fluid used was CO2 and variables such as density, temperature of thimbles, extraction time, modifier, fluid flow, and kind of traps were investigated. Several experiments were carried out to obtain the most favorable conditions for analysis of volatile nitrosamines in sausages. The recoveries ranged from 21 to 82% for the five nitrosamines studied. The optimal condition of extraction was 0.2 g of sample fortified with 10 mg/kg, using dynamic extraction during 20 min and with adsorbent Florisil in the trap. The solvent selected for the elution of the analytes was methanol.  相似文献   
4.
Agroforestry Systems - Small mammals interfere in plant dynamics through seed and seedling predation, and seed dispersion. In anthropogenic systems, some species provide ecosystem services while...  相似文献   
5.
Three cultivars of wheat showing different levels of spontaneous karyotypic instability were studied regarding their stability in vitro for a number of characters, i.e. chromosome structure, gliadin pattern, glume and grain colour, awn type, chlorophyll pigmentation and plant morphology. The progenies of somaclones derived from immature embryos of both aneuploid and euploid plants were used in this study along with foundation seeds and a large number of their sexual progeny in order to discriminate between pre-existent variability and any novel variation induced by the in vitro culture. Only one translocation not described before and a new gliadin pattern were detected which could be ascribed to the effects of tissue culture, suggesting that this technique is not effective for inducing novel variation for breeding purposes in wheat.  相似文献   
6.
The objectives of this study were to optimize RAPD and AFLP techniques in B. catharticus, and to determine the genetic variability of populations and commercial prairie grass cultivars with the aforementioned molecular markers. Two populations with contrasting morphological characteristics were evaluated from individual and bulked DNA samples using RAPD markers. Both analyses showed a similar information about inter population variability. Each accession was sampled by a single leaf bulk of 10 plants. Accession similarities were established with 276 RAPD and 714 AFLP bands using Jaccard similarity coefficient. The dendrogram of the accessions using RAPD markers showed that they shared high similarity values (>94%). A similar result was obtained with AFLP markers (similarity values >98%), revealing a narrow genetic basis in the analyzed accessions. Consequently, molecular characterization of germplasm should be considered in addition to morphological criteria, to choose the parental genotypes for breeding programs of this forage crop. The AFLP technique was more efficient to detect DNA polymorphism in our experiments and unique fingerprints were detected for all the accessions. RAPD is a simple and non expensive technique, suitable to estimate genetic similarity. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
7.
We have used 19 SSR markers to fingerprint 41 local potato cultivars from 10 locations of Tenerife Island. These varieties represent relicts of the early introductions originating from South America and have been characterised previously morphologically and ecophysiologically. The SSR primers generated a varying degree of polymorphisms. A total of 67 alleles were observed, 12 of them were present in all cultivars. Several accession and group specific alleles were detected. Similarity coefficients were computed from the molecular data and cluster analyses were performed. Generally, cultivar groups with identical or related common names showed the same SSR patterns or clustered closely together. According to the molecular patterns misleading or confounded names were evident for four accessions. The dendrogram clusters were generally in good agreement with previous classifications of the accessions as Solanum tuberosum subsp. andigena, S. tuberosum subsp. tuberosum and Solanum chaucha genotypes. However in four cases the molecular patterns showed discrepancies with previous species assignments suggesting the need for a more detailed and comparative study of these accessions.  相似文献   
8.
The high-temperature treatment of paprika oleoresins (Capsicum annuum L.) modified the carotenoid profile, yielding several degradation products, which were analyzed by HPLC-APCI-MS. From the initial MS data, compounds were grouped in two sets. Set 1 grouped compounds with m/z 495, and set 2 included compounds with m/z 479, in both cases for the protonated molecular mass. Two compounds of the first set were tentatively identified as 9,10,11,12,13,14,19,20-octanor-capsorubin (compound II) and 9,10,11,12,13,14,19,20-octanor-5,6-epoxide-capsanthin (compound IV), after isolation by semipreparative HPLC and analysis by EI-MS. Compounds VII, VIII, and IX from set 2 were assigned as 9,10,11,12,13,14,19,20-octanor-capsanthin and isomers, respectively. As these compounds were the major products formed in the thermal process, it was possible to apply derivatization techniques (hydrogenation and silylation) to analyze them by EI-MS, before and after chemical derivatization. Taking into account structures of the degradation products, the cyclization of polyolefins could be considered as the general reaction pathway in thermally induced reactions, yielding in the present study xylene as byproduct and the corresponding nor-carotenoids.  相似文献   
9.
Firmly established methylcholanthrene fibrosarcomas in syngeneic mice will totally disappear if the hosts are treated with living tumor cells that have been exposed to Vibrio cholerae neuraminidase in vitro. The effect is magnified by the simultanieous injection of a nonspecific immunostimulant, BCG. The rejection of the methylcholanthrene tumor is immunospecific and can be induced only with tumor cells, treated with Vibrio cholerae neuraminidase, identical in type with the growing tumor.  相似文献   
10.
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