PrP genotypes of rare breeds of sheep in Great Britain

In total 31,669 blood samples were collected from 1187 flocks of 27 rare breeds of sheep in the UK, and their genotype profiles at the prion protein locus were determined. The frequencies of the five alleles varied widely among the breeds and some had only two of the alleles and others had all five; the average was three. The average allele frequencies across all 27 breeds were 49.7 per cent for ARR, 4.4 per cent for AHQ, 2.7 per cent for ARH, 37.4 per cent for ARQ and 5.8 per cent for VRQ. The highest frequencies for each allele were 90.7 per cent for ARR in the Leicester Longwool, 24.7 per cent for AHQ in the Hebridean, 68.7 per cent for ARH in the Manx Loghtan, 98.7 per cent for ARQ in the North Ronaldsay and 28.4 per cent for VRQ in the Boreray. All 27 breeds had the ARR allele, 21 had AHQ, 11 had ARH, 26 had ARQ and 20 had VRQ.     

Secondary plant metabolites as targets for genetic modification of crop plants for pest resistance

Three genetic manipulation strategies are described for enhancing the effectiveness of secondary metabolites of crop plants in reducing pest and disease damage. Targets for gene transfer studies are secondary metabolites of oilseed rape, lepidopteran sex pheromones and drimane anti-feedants. Initial work towards isolation of genes for the biosynthesis of drimane anti-feedants is described.     

Dog-human and dog-dog interactions of 260 dog-owning households in a community in Cheshire

This study investigated the nature and frequency of the contacts that occur between dogs, and between dogs and people, by means of a questionnaire survey of 260 dog-owning households in a community in Cheshire, uk. The contacts were highly variable and were affected by the size, sex and age of the dog, individual dog behaviours, human behaviours and human preferences in the management of the dog. A number of situations were identified that may be important in relation to zoonoses, including sleeping areas, playing behaviours, greeting behaviours, food sources, walking, disposal of faeces, veterinary preventive treatment and general hygiene.     

Monitoring derelict urban land: A review of problems and potentials of remote sensing techniques

The accelerating rate of change in urban areas calls for more rapid and cost-effective surveys of derelict land. A review of the use of remote sensing¹ for this task reveals that, although aerial photography has been used for urban analysis since the 1940s, it has not been widely adopted for surveys of derelict land, despite demonstrations of its utility. Other forms of remote sensing are similarly shown to have been little-used and to have had patchy success. The hitherto restricted utility of remote sensing is found to be due to a combination of limitations of the forms of imagery available and the methods of analysis employed. Recent changes in available remote sensing imagery, notably the higher resolution now provided by the SPOT satellite, coupled with advances in digital image-processing techniques point to improved opportunities for using remote sensing to monitor derelict land. As a demonstration of these developments, a texture image based on scene variance is derived from a SPOT image of part of north Staffordshire. All derelict and neglected land parcels larger than 1.25 ha are delimited on this image. Remote sensing techniques are not yet ready to supplant detailed ground surveys but they have a growing role to play in monitoring various aspects of land dereliction.     

Gene pool and connectivity patterns of Pinna nobilis in the Balearic Islands (Spain,Western Mediterranean Sea): Implications for its conservation through restocking

相似文献   

Insecticidal and repellent properties of nine volatile constituents of essential oils against the American cockroach,Periplaneta americana (L.)

The toxic and repellent properties of nine major constituents of essential oils, comprising benzene derivatives and terpenes, were evaluated against Periplaneta americana (L.). Contact and fumigant toxicities to adult females and repellency to nymphs were determined. The decreasing order of knockdown activity via contact was methyl-eugenol>isosafrole=eugenol>safrole. The killing effect via contact was in the order eugenol=methyl-eugenol=isosafrole>safrole. Fumigant toxicity was only observed for safrole and isosafrole, with safrole being the more potent. Isoeugenol and the tested terpenes had neither contact nor fumigant toxic effect. The decreasing order of repellency to nymphs was safrole>isosafrole>methyl-eugenol=α-pinene> eugenol>isoeugenol. The benzene derivatives were generally more toxic and repellent to P. americana than the terpenes. The distance of the side chain double bond from the aromatic ring and the substitution of a methoxy group to these compounds appeared to be important determinants of their toxicity and repellency. © 1998 Society of Chemical Industry     

Antigenic and morphological differentiation of placental and intestinal isolates of Chlamydia psittaci of ovine origin.

Ewe placental and lamb intestinal isolates of Chlamydia psittaci recovered from flocks affected with ovine enzootic abortion were examined by inclusion morphology, indirect immunofluorescence (IIF) and immunoblot analysis. Chlamydiae recovered from the faeces of sheep from two flocks free of clinical disease were also examined. In cell culture ovine abortion (OA) and intestinal isolates were distinguishable by inclusion development and morphology. Similarly, in two-way IIF tests with one week mouse antisera isolates fell into two distinct groups: abortion or intestinal. Immunoblotting with convalescent sheep abortion antiserum identified 30 out of at least 40 silver staining polypeptides as antigenic both in OA and intestinal isolates. The serum produced a similar reaction pattern to the resolved proteins of each OA isolate, indicating a higher degree of antigenic conservation among these isolates. Considerable cross reactivity between the OA and intestinal isolates was identified, but the serum also showed apparent molecular weight differences between antigens of the two types in the 87-116 kDa, 38-44 kDa and 26-28 kDa regions. Furthermore, the immunoblotting analysis revealed heterogeneity among the intestinal isolates, particularly in antigens between 87-116 kDa and 38-44 kDa.