Evidence that resistance to potato leafroll virus accumulation in tetraploidsolarium tuberosum L. is controlled by one or few major genes that are not complementary

Summary Previous investigations into the inheritance of resistance to accumulation of potato leafroll virus indicated a dominant major-gene effect, but the segregation ratios in progenies of crosses were a closer fit to a model involving two complementary genes (both required for resistance and one present in the susceptible parent cultivar, Maris Piper) than to a single gene model. In this study, we tested the complementary gene hypothesis by backcrossing susceptible segregants from one of these progenies to their susceptible parent, Maris Piper. No resistant segregants were found in the five backcross progenies examined, so the complementary gene hypothesis was not supported. There was significant variation between susceptible progeny-members in these backcrosses. The progeny of another, highly resistant parent clone, G. 8107(1), selfed, was also examined: all members were resistant. Whilst there is evidently a dominant major-gene effect involved, this is not the whole picture and there are other unidentified genetic effects.     

The measurement of chlorogenic acid in potato leaf extracts by high-pressure liquid chromatography

Summary Chlorogenic acid concentration in potato leaf extracts was measured by a modification of existing high-pressure liquid chromatography methods. Concentrations were in the range of 48–327 μg/g fresh weight and varied with leaf position and age. There was no correlation between chlorogenic acid concentration in different potato clones and their resistance to infection with potato leafroll virus.     

Rapid Methods to Predict Soft-Wheat Dough Quality for Specific Food Products

A flour miller must provide flour with the potential to produce dough properties suited to the specifications for food manufacturers involved with a range of food products. This difficult task could be simplified if grain of suitable dough-forming potential was segregated at harvest and delivered for milling. To achieve the identification of grain of suitable dough-quality potential, various published testing systems were adapted and evaluated using a total of 149 grain samples from five successive harvests to establish procedures that could be applied to “running samples”, each representing the contents of a specific storage cell. Some of the methods proved to be inadequate for this purpose. The best possibilities were methods based on the swelling index for glutenin (SIG) principle. The SIG test, combined with grain-protein content, is suitable for screening large numbers of wheat meal samples, making it possible for mill buyers to select stored grain lots that will suit the flour dough strength specifications for specific customers and their food products.     

Soil dwelling macro‐invertebrates in intensively grazed dairy pastures in Pennsylvania,New York and Vermont

This study estimates the relative contributions of environment and farm management strategies in influencing soil faunal assemblages and attempts to identify the species with potential to affect sustainability of intensive grazing management systems in the north‐eastern USA. It arises because of the change from confinement feeding of dairy cattle, consequent upon concerns about negative environmental effects, the rising costs for machinery and housing, and reduced profit margins, together with the absence of data from which the consequences of such change on the soil fauna may be predicted. Macro‐invertebrates were sampled in soil from seventy‐eight grazed pastures on twenty‐one dairy farms in Pennsylvania, USA, in the spring of 1994. On five of these farms, macro‐invertebrates were sampled (four pastures per farm) in the spring, summer and autumn seasons of 1994, 1995 and 1996. In 1997, macro‐invertebrates were sampled in soil during spring, summer and autumn from (four pastures per farm) on three farms in New York, and during spring and summer on three farms in Vermont. Species richness ranged from two to twelve species (mean 6·4) per pasture site in Pennsylvania and five to eighteen species (mean 10·7) in New York and Vermont. The communities were dominated at most sites by earthworms. Earthworms were correlated with soil basal and substrate‐induced respiration/carbon ratio, and soil moisture, but were negatively correlated with cows per hectare and herbage biomass in Pennsylvania. Sitona larvae were recorded at nineteen of the twenty‐one farms during the spring of 1994 across Pennsylvania and occurred at populations >5 m^?2 in 68% of the sampled pastures. Sitona larvae were less abundant in New York and Vermont. Elaterid larvae comprised a complex of seven species of which Aeolus melillus (Say) and Melanotus communis (Gyllenhal) comprised 35% and 39%, respectively, of the elaterids collected in Pennsylvania. Agriotes mancus (Say) and Ctenicera destructor (Brown) comprised 41% and 26%, respectively, of four species collected in New York and Vermont. Scarabaeid larvae, comprising a complex of eight species, were detected at only 27% of the seventy‐eight pastures sampled in spring 1994 in Pennsylvania. Five species were collected in ten of the twelve New York pastures and four species in nine of the twelve Vermont pastures. Populations of scarabaeid larvae averaged <25 m^?2 in all three states, except in three Pennsylvania pastures in spring 1994. Detrended canonical correspondence analysis (DCCA) showed pasture standing biomass, legume diversity, pre‐winter stubble height, white clover pasture content, and soil phosphorus levels influenced numbers of invertebrate species more than climatic factors, such as temperature, rainfall, altitude, latitude and seasonal water table. DCCA also showed most pastures to be close to the average of environmental factors. The extremely low density of herbivorous macro‐invertebrates in soil and the absence of pest outbreaks may indicate a stable soil ecosystem.     

Epidemiological study of pasture-associated laminitis and concurrent risk factors in the South of England

A retrospective study of laminitis was carried out to identify risk factors associated with this disease on an East Anglian farm with approximately 1000 animals living in an area of 1000 acres. Medical records between January 1997 and May 2000 and between April 2005 and March 2008 were reviewed, and the age, sex, weight (kg), height (inches [in] and hands [H]) and weight-to-height ratio (kg/in) was recorded. The prevalence, incidence and seasonality of laminitis were determined and their relationship to the monthly temperature, rainfall and hours of sunshine was evaluated. Averaged over the six years, the highest prevalence (2.6 per cent) and incidence (16 cases/1000 animals) of laminitis occurred in May. The findings of a multivariate analysis revealed that females (P=0.007, odds ratio [OR] 1.46, 95 per cent confidence interval [CI] 1.1053 to 1.9646) and light animals (P ≤ 0.001, OR=0.995, 95 per cent CI =0.9932 to 0.9963) had the greatest risk of developing laminitis. A positive association was found between hours of sunshine and incidence (P=0.007, relative risk [RR] 1.009, 95 per cent CI 1.001 to 1.012) and prevalence (P=0.002, RR 1.008, 95 per cent CI 1.003 to 1.012) of laminitis. The data suggest that there is a relationship between season, sex of the animal and the development of laminitis.     

Lesions of right heart failure and ascites in broiler chickens

A naturally occurring cardiomyopathy in broiler chickens from a single Ontario farm was studied in order to define the morphologic changes. Gross and histologic features of affected birds were compared with those in age-matched control penmates. Body weight and weight and volume of individual cardiac chambers were measured. Histologic sections of 18 different tissues were examined, and lesions observed were scored subjectively. Affected birds were stunted and had marked right ventricular dilation and hypertrophy, atrial hypertrophy, ascites, pulmonary congestion and edema, and hepatic capsular fibrosis. Microscopic changes in the heart of affected birds were mild and did not suggest a specific cause of heart failure. Lungs had marked hypertrophy of parabronchial smooth muscle and collapse and apparent loss of associated air capillaries. Other histologic changes observed were thought to be the result of passive congestion of viscera caused by right heart failure and chronic debility. Although the specific etiology of this condition could not be determined, it was felt that this syndrome was unlikely to have been the result of any of the commonly recognized causes of congestive heart failure and ascites in broilers.     

Disposition of fenbendazole in the rabbit

The disposition of fenbendazole was studied in rabbits following either oral or intravenous administration. The major metabolites appearing in plasma were fenbendazole sulphoxide (oxfendazole) and fenbendazole sulphone. Calculation of the total urinary and faecal elimination of the drug and of its known metabolites showed that only 40 per cent of the dose was recovered after oral dosing; 29.7 per cent after an intravenous dose. The sulphoxide and sulphone were minor elimination products. The major excretory metabolite was p-hydroxyfenbendazole.     

Pharmacokinetics and metabolism of fenbendazole in channel catfish

Fenbendazole (FBZ) was administered intravenously (1 mg/kg) and orally (5 mg/kg) to catheterized, confined channel catfish. Blood samples were collected for 72 h, and resulting FBZ plasma concentrations were pharmacokinetically modelled. Following intravenous administration t1/2 was 0.51 h, t1/2 was 16.8 h, body clearance (C1b) was 0.0598 L/kg/h, and Vd (area) was 1.45 L/kg. After oral administration the t1/2 (abs) was 1.47 h, the t1/2 was 20.1 h, and the tlag was 0.1 h.Following oral administration of 5 mg FBZ/kg body weight, the following tissues and body fluids were sampled for concentrations of FBZ, oxfendazole (FBZ-SO), sulphone metabolite (FBZ-SO₂) and hydroxy metabolite (FBZ-OH): liver, posterior kidney, fat, muscle, bowel contents and urine. Fenbendazole was detected in the highest concentrations in abdominal fat, whereas oxfendazole was found primarily in the kidney, liver and abdominal fat. The sulphone metabolite was detected only in urine and bowel contents, while the hydroxy metabolite was found most often in the liver and abdominal fat samples.