The intensity of resistance by mature Merino ewes against Haemonchus contortus and Tichostrongylus colubriformis in single-species and combined-species infection     

DB ADAMS  JJ LYNCH†  BH ANDERSON  LR FELL‡  GN HINCH§  RK MUNRO¶ 《Australian veterinary journal》1990,67(12):443-445

Three-year-old, non-lactating and non-pregnant Merino ewes, raised on pasture under a program of strategic treatment with anthelmintic and found to be extremely resistant to "trickle" infection with Haemonchus contortus, were given single-dose infections with either H. contortus or Trichostrongylus colubriformis or both species together. The purpose was to ascertain the intensity of protective immunity against the 2 parasites in sheep with immunity acquired from a presumably slight exposure to infection. To provide a criterion, some infected ewes were immunosuppressed with corticosteroid, dexamethasone. Untreated ewes were extremely resistant to challenge infection with either 15,000 or 150,000 H. contortus or 15,000 T. colubriformis. Surprisingly, when mixed infection was given, egg counts for H. contortus were significantly elevated compared with infection by that species alone. Antibody to antigens from infective larval and adult H. contortus was measured in serum by enzyme-linked-immunosorbent assay (ELISA) during the course of infection. Serum titres against larval antigens were significantly depressed when infections with either H. contortus or T. colubriformis were permitted by immunosuppression with dexamethasone, whereas those against adult antigen were depressed when infection with T. colubriformis was permitted.  相似文献   

The distribution of barley yellow mosaic virus (BaYMV) and barley mild mosaic virus (BaMMV) in UK winter barley samples, 1987-1990     

M. J. ADAMS 《Plant pathology》1991,40(1):53-58

Improved diagnosis of barley yellow mosaic (BaYMV) and barley mild mosaic (BaMMV) viruses was obtained by adjusting the buffers used in immunospecific electron microscopy (ISEM) to ensure a pH ≥ 7-0 and in ELISA by replacing ovalbumin with 10 g/l full cream milk powder.
Over 70% of samples of winter barley with symptoms of mosaic received from different sites in the UK during 1987-90 had BaYMV and 37% had BaMMV, with 11% containing both viruses. BaMMV was much more common on malting cultivars than on those grown for feed and this resulted in an easterly bias to the geographical distribution of the virus. Both viruses were, however, widely distributed in areas where winter barley is grown intensively. A small number of BaYMV records were from cultivars previously regarded as resistant and these are probably a distinct strain of the virus.  相似文献   

Parry's disease of pears is similar to pear decline and is associated with mycoplasma-like organisms transmitted by Cacopsylla pyricola   总被引：1，自引：1，他引：1  

D. L. DAVIES  C. M. GUISE  M. F. CLARK  A. N. ADAMS 《Plant pathology》1992,41(2):195-203

Mycoplasma-like organisms (MLOs) were detected by fluorescence microscopy in a number of pear cultivars and pear seedlings growing under a range of different conditions. In the cultivar Conference, MLOs were consistently associated with symptoms of Parry's disease, a decline-like disease of young trees with quince rootstocks. MLO-free pear seedlings rapidly became infected when they were planted outside. Experimental transmission of MLOs to pear seedlings and Conference trees was achieved using pear psyllids, caught outside or raised on infected plants under controlled conditions. Conference trees in an orchard trial remained free from the severe spring symptoms of Parry's disease when they were protected from feeding insects during spring of the previous year. MLOs were graft transmissible, but were not perpetuated by the standard propagation practices of budding or grafting when quince rootstocks were used. Parry's disease appears to be similar to pear decline, an MLO-induced disease well established in several other parts of the world. It is suggested that Parry's disease should be referred to as pear decline.  相似文献   

The Growth of Red Beet and its Infection by Streptomyces spp.   总被引：1，自引：1，他引：0  

M. J. ADAMS  D. H. LAPWOOD  BARBARA RANKIN 《Plant pathology》1976,25(3):147-151

  相似文献   

Abdominal Crisis in the Horse: A Comparison of Pre-Surgical Evaluation With Surgical Findings and Results     

STEPHEN B. ADAMS D.V.M.  C. WAYNE McILWRAITH B.V.Sc  M.S.  M.R.C.V.S. 《Veterinary surgery : VS》1978,7(3):63-69

The results of preoperative examination, surgical intervention and the outcome of 50 cases of acute abdominal crisis in the horse are presented. Pre-surgical parameters discussed in this correlative study include duration of the condition prior to sergery, pulse rate, packed cell volume (PCV), abdominal distention, intestinal motility and tympany, rectal findings, reflux of fluid after passage of a nasogastric tube, and abdominal paracentesis. A retrospective study was performed to evaluate the usefulness of each clinical parameter in deciding that a case was surgical, arriving at a specific pre-surgical diagnosis, and in giving a prognosis. Rectal examination was the single most useful diagnostic tool. Reflux of gastric fluid through the nasogastric tube usually indicated obstruction of the small intestine.  相似文献   

Some biochemical properties and antibiotic sensitivities of Pasteurella piscidda isolated in Greece and comparison with strains from Japan, France and Italy     

V. BAKOPOULOS  A. ADAMS  R. H. RICHARDS 《Journal of fish diseases》1995,18(1):1-7

Abstract The biochemical properties and antibiotic sensitivity patterns of 13 Pasteurella piscicida isolates from Greece are described and compared with 10 Japanese and five European (Italian and French) isolates. Morphologically and biochemically, all isolates of P. piscidda tested were nearly identical and only minor differences could be detected with reference to the level of acid production from sugars (especially from glucose). Greek, Italian and French isolates showed similar antibiotic sensitivity patterns, being resistant to erythromycin, kanamycin and streptomycin, and sensitive to most of the other antibiotics tested. Resistance was also demonstrated for some isolates towards the potentiated sulphonamides. The Japanese isolates appeared to be resistant to a larger range of antibiotics including erythromycin, kanamycin, streptomycin, oxolinic acid, oxytetracycline and chloramphenicol. Multiple resistance of Japanese strains was also noted. These results are discussed in the light of future measures for the control of pasteurellosis.  相似文献   

Composition and properties of poorly ordered minerals in Welsh soils. II. Phosphate adsorption and reactivity towards NaF solution     

W. A. ADAMS  S. N. GAFOOR  M. I. KARIM 《European Journal of Soil Science》1987,38(1):95-103

Eleven horizons of acidic soils developed from Lower Palaeozoic sedimentary rocks in mid Wales contained varying amounts of poorly ordered minerals. In nine of these over 70% of the phosphate adsorption capacity was attributed to poorly ordered minerals. Iron oxide with substituted Al, and a separate Al oxide, together accounted for the phosphate adsorption of the poorly ordered fraction. Aluminium-substitution had no major effect on the adsorption capacity of Fe oxide, but since Al occurred in both active minerals it masked the effect of Fe on phosphate adsorption in simple correlations. The relative contribution of the two mineral forms to phosphate adsorption varied widely between soils. Aluminium as a substituent in Fe oxide and in 'free' oxide form was responsible for the soils' reactivity towards NaF, but no distinction could be made between these poorly ordered forms. For certain horizons both poorly ordered Al and Si were correlated with OH⁻ release, but Al oxides were more important than silicates.  相似文献   

QUANTITATIVE PEDOLOGICAL STUDIES ON SOILS DERIVED FROM SILURIAN MUDSTONES     

L. J. EVANS  W. A. ADAMS 《European Journal of Soil Science》1975,26(3):327-335

The uniformity of the parent material between and within five soil profiles representing a typical catenary sequence in upland mid-Wales was investigated using as criteria of uniformity the constancy of the ratios Zr: Sr and quartz: illite in the silt fractions. No lithologic breaks could be detected in the soil profiles. ZrO₂, TiO₂, quartz, and tri-acid residue were assessed for use as internal standards. TiO₂ appeared to be mobile during pedogenesis. Of the other three standards tri-acid residue was considered to be most suitable.  相似文献   

Variation of the critical-state boundaries of an agricultural soil     

B. A. ADAMS  D. WULFSOHN 《European Journal of Soil Science》1997,48(4):739-748

The critical-state theory can be applied profitably to analyse the mechanical behaviour of agricultural soil. Critical-state parameters and other soil properties are affected by the microstructure and unsaturated nature of agricultural soils. We determined the critical-state boundaries of an agricultural soil in both saturated and unsaturated triaxial tests and examined the effects of matric suction and initial structure on critical-state boundaries. On the compression plane, the presence of air and matric suction in the pores of unsaturated soil significantly affected critical-state boundaries by increasing compressibility, λ On the deviatoric stress-mean net stress plane, the strength increased with matric suction. On this plane, the critical-state lines for the unsaturated tests had non-zero intercepts. For a given soil structure, the frictional parameter M remained fairly constant with matric suction change. However, a change in the initial microstructure resulted in a change in M, causing the position of the critical-state line to ‘pivot’ in state space.  相似文献   

Epizootic diarrhea of infant mice: indentification of the etiologic agent     

ADAMS WR  KRAFT LM 《Science (New York, N.Y.)》1963,141(3578):359-360

Electron micrographs of intestinal epithelium of infant mice infected with epizootic diarrhea virus have demonstrated intracellular spherical structures measuring 65 to 75 m(micro) in diameter which have a complex morphology resembling several virus particles. They have ben interpreted as being the etiologic agent of this disease. The particles were present in association with, in some cases within, vesicles of the endoplasmic reticulum of intestinal epithelial cells. They were never seen in the nucleus.  相似文献