An improved ferritin assay for canine sera     

Andrews GA  Smith JE  Gray M  Chavey PS  Weeks BR 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1992,21(2):57-60

An improved serum ferritin assay for canine serum has been developed. It uses two monoclonal antibodies in a sandwich arrangement. Serum ferritin can be determined on undiluted canine sera with this assay. The recovery of ferritin added to canine serum ranged from 98 to 106%, the within-assay coefficient of variability was 3.3 to 4.5%, and the assay-to-assay variability was 9.8 to 10.2%. Serum ferritin from 61 apparently healthy dogs had a geometric mean of 252 ng/ml, with a range of 80 ng/ml to 800 ng/ml.  相似文献   

Temperature cycling periods affect growth and tuberization in potatoes under continuous irradiation     

Cao W  Tibbitts TW 《HortScience : a publication of the American Society for Horticultural Science》1992,27(4):344-345

Plants of the potato (Solanum tuberosum L.) cultivars Denali, Norland, Haig and Kennebec were grown for 42 days under three temperature cycling periods (thermoperiods) with continuous irradiation in two repeated experiments to help determine if temperature cycling might be varied to optimize tuber development of potatoes in controlled environments. Thermoperiods of 6/6 hours, 12/12 hours and 24/24 hours were established with the same temperature change of 22/14C and same controlled vapor pressure deficit of 0.60 kPa. The thermoperiod of 24/24 hours significantly promoted tuber initiation but slowed tuber enlargement in all four cultivars, compared to the thermoperiods of 6/6 hours and 12/12 hours. Denali' produced the highest tuber and total dry weights under the 6/6 hours thermoperiod. Kennebec' produced the highest tuber dry weight under the 12/12 hours thermoperiod. Thermoperiods had no significant effect on shoot and root dry weights of any cultivars. The major effect of thermoperiods was on initiation and enlargement of tubers.  相似文献   

Foot-and-mouth disease virus typing by complement fixation and enzyme-linked immunosorbent assay using monovalent and polyvalent antisera.   总被引：1，自引：0，他引：1  

A Alonso  M A Martins  M da P Gomes  R Allende  M S S?ndahl 《Journal of veterinary diagnostic investigation》1992,4(3):249-253

An indirect "sandwich" enzyme-linked immunosorbent assay (ELISA) using polyvalent and monovalent antisera was compared with the 50% complement fixation (CF50) test for the detection of foot-and-mouth disease (FMD) O, A, and C virus types. ELISA was more sensitive than CF50 tests when polyvalent antisera were used for detecting the 3 types of virus in epithelial samples, whereas ELISA using monovalent antisera was the least sensitive technique. The ELISA performed with polyvalent antisera was 9 times more sensitive for detecting FMD virus than that with monovalent antisera. However, viral isolation in cell culture was the most sensitive detection system. The combined use of ELISA with polyvalent antisera and cell culture inoculations was the most effective procedure for identifying FMD virus in epithelial samples from the field.  相似文献   

The legitimacy of single and group housing of breeding sows]     

S Stamer  E Ernst 《DTW. Deutsche tier?rztliche Wochenschrift》1992,99(4):151-154

Current German law on animal rights requires protection and appropriate treatment of animals. However, information on breeding and raising swine is incomplete, and comparison studies of alternative housing systems are needed. Therefore, the effects of single and group housing of pregnant sows on piglet production was investigated in the 120-sow herd of the Institute for Animal Breeding and Husbandry of the University of Kiel. Reproductive traits, general health and behaviour studies were evaluated over one year. Type of housing system was found to have no effect on number of piglets born alive or dead or on days open. Daily gain was influenced. Daily gain of single-housed sows increased but without any difference in feed intake. General health was measured by nutritional condition, soiling, callosity, and injuries at time of evaluation. Single-housed sows had more calluses and were more soiled compared with group-housed sows. Injuries occurred more often in group housing, especially when new animals were integrated into the group. However, injuries were not serious. Animal behaviour was recorded on video during one pregnancy period of 60 sows. The housing system effected "sitting" and "lying" behaviour. Behaviour also is influenced by pregnancy in both housing systems. Equal incidences of abnormal behaviour, considered as sham-chewing, were found in both housing systems.  相似文献   

The biochemical basis of resistance of potato to soft rot bacteria     

G. D. Lyon  J. Heilbronn  R. S. Forrest  D. J. Johnston 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(2):127-133

Evidence is presented that a number of mechanisms are involved in the resistance of commercial cultivars of potato to soft rottingErwinia spp. These include phytoalexins, phenolics, cell wall modification, and possibly proteins. The role of elicitor-active oligogalacturonides, which are released from plant cell walls by pectic enzymes, is discussed.  相似文献   

Virus transmission by aphids in potato crops     

J. A. T. Woodford 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(Z2):47-54

This paper reviews the contribution of vector activity and plant age to virus spread in potato crops. Determining which aphid species are vectors is particularly important for timing haulm destruction to minimize tuber infection by potato virus Y (PVY). Alate aphids of more than 30 species transmit PVY, and aphids such asRhopalosiphum padi, that migrate in large numbers before flights of the more efficient vector,Myzus persicae, appear to be important vectors. Differences in methodology, aphid biotypes and virus strains prevent direct comparisons between estimates of vector efficiencies obtained for aphids in different countries in north western Europe. M. persicae is also the most efficient vector of potato leafroll virus (PLRV), but some clones ofMacrosiphum euphorbiae transmit PLRV efficiently toNicotiana clevelandii and potato test plants. The removal of infected plants early in the season prevents the spread of PLRV in cool regions with limited vector activity. The proportion of aphids acquiring PLRV from infected potato plants decreases with plant age, and healthy potato plants are more resistant to infection later in the season. Severe symptoms of secondary leafroll developed on progeny plants of cv. Maris Piper derived from mother plants inoculated with PLRV in June or July of the previous year. Progeny plants derived from mother plants inoculated in August showed only mild symptoms, but the concentration of PLRV in these plants was as high as that in the plants with severe symptoms.  相似文献   

Genetic mapping and utilization of quantitative trichome-mediated insect resistance in potato     

M. Bonierbale  R. Plaisted  S. Tanksley 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(Z2):211-214

Introgression of trichome-mediated insect resistance from the wild speciesSolanum berthaultii has become a major focus of the potato improvement program at Cornell University during the past twelve years. Several quantitative characters are involved in this resistance which is effective against a wide range of pest types. Correlative biochemical assays have been developed to assay specific components of the resistance, and the effects of the resistance on the target pests have been studied. Quantitative laboratory assays and specific measurements of insect behavior and biology have increased the precision of selection and enable the investigation of the genetic control of the resistance.We are currently using restriction fragment length polymorphisms (RFLPs) for genetic mapping of factors controlling the trichome traits fromS. berthaultii. Backcrosses to both the wild and the cultivated species parents have been evaluated for phenotypes contributing to the resistance mechanism, including trichome density, sucrose ester and polyphenol oxidase production by the trichomes, and the enzymatic browning reaction responsible for insect entrapment. Genetic maps are being developed for these progenies, using RFLP markers previously mapped in potato. Field and greenhouse trials under insect infestations are also being conducted with the mapping progeny. Our goal is to locate genes responsible for quantitative insect resistance by correlating RFLP variation at mapped loci with the trichome phenotypes and insect resistance. Genetic markers for these traits will be useful in transfer of the effective wild chromosomal segments into and among tetraploid potatoes, and for a better understanding of the resistance mechanism.  相似文献   

New predators for biocontrol under glass     

R. J. Chambers  S. Long 《Phytoparasitica》1992,20(1):S57-S60

Several species ofOrius are under investigation in the UK, Europe and North America for the biological control of thrips, especially western flower thrips(Frankliniella occidentalis). The available species are briefly compared and findings on effectiveness and oviposition ofO. laevigatus are reported.  相似文献   

Response of five temperate deciduous tree species to water stress     

Ranney TG  Whitlow TH  Bassuk NL 《Tree physiology》1990,6(4):439-448

Gas exchange, tissue water relations, and leaf/root dry weight ratios were compared among young, container-grown plants of five temperate-zone, deciduous tree species (Acer negundo L., Betula papyrifera Marsh, Malus baccata Borkh, Robinia pseudoacacia L., and Ulmus parvifolia Jacq.) under well-watered and water-stressed conditions. There was a small decrease (mean reduction of 0.22 MPa across species) in the water potential at which turgor was lost (Psi(tlp)) in response to water stress. The Psi(tlp) for water-stressed plants was -1.18, -1.34, -1.61, -1.70, and -2.12 MPa for B. papyrifera, A. negundo, U. parvifolia, R. pseudoacacia, and M. baccata, respectively. Variation in Psi(tlp) resulted primarily from differences in tissue osmotic potential and not tissue elasticity. Rates of net photosynthesis declined in response to water stress. However, despite differences in Psi(tlp), there were no differences in net photosynthesis among water-stressed plants under the conditions of water stress imposed. In A. negundo and M. baccata, water use efficiency (net photosynthesis/transpiration) increased significantly in response to water stress. Comparisons among water-stressed plants showed that water use efficiency for M. baccata was greater than for B. papyrifera or U. parvifolia. There were no significant differences in water use efficiency among B. papyrifera, U. parvifolia, A. negundo, and R. pseudoacacia. Under water-stressed conditions, leaf/root dry weight ratios (an index of transpiration to absorptive capacity) ranged from 0.77 in R. pseudoacacia to 1.05 in B. papyrifera.  相似文献   

Growth and erosion of thin solid films     

Bales GS  Bruinsma R  Eklund EA  Karunasiri RP  Rudnick J  Zangwill A 《Science (New York, N.Y.)》1990,249(4966):264-268

Thin films that are grown by the process of sputtering are, by and large, quite unlike the smooth, featureless structures that one might expect. In general, these films have a complicated surface morphology and an extended network of grooves and voids in their interiors. Such features can have a profound effect on the physical properties of a thin film. The surface irregularities and the bulk defects are the result of a growth instability due to competitive shadowing, an effect that also plays a role in geological processes such as erosion. For amorphous thin films, the shadow instability can be described by a remarkably simple model, which can be shown to reproduce many important observed characteristics of thin film morphology.  相似文献