Can wild relatives of sorghum provide new sources of resistance or tolerance against Striga species?

Summary The genus Striga contains some of the most noxious parasitic plants, which have a devastating impact on cereal production in Africa; of most importance are Striga hermonthica and Striga asiatica . Complete resistance to infection by Striga species does not exist in cultivated cereals. Of great interest is the possibility that wild relatives of cereals may provide a genetic basis for resistance or tolerance to infection and may be of enormous value for the development of resistant crops. A wild relative of cultivated sorghum, Sorghum arundinaceum , demonstrated tolerance to infection by S. asiatica , with little impact of S. asiatica on host growth or grain production compared with the detrimental impact of the parasite on cultivated sorghum. Infection by S.hermonthica , however, had a significant influence on host performance for both wild and cultivated sorghum. Differences in host:parasite responses may be explained by the timing of parasite attachment and differences in host specificity for these two Striga species.     

Plasma cortisol responses to three cortico-trophic preparations in normal dogs

Objective To compare cortisol responses to three corticotrophic preparations in normal dogs.
Animals Eight clinically normal dogs (four intact males, four intact females) of medium size.
Procedures Each dog received four treatments on four separate occasions in a duplicated Latin square pattern. Treatments were two adrenocorticotrophin (ACTH) preparations given intramuscularly at 2.2 U/kg, one of the ACTH preparations given intramuscularly at 1 U/kg and a synthetic polypeptide with ACTH-like activity (tetracosactrin, cosyntropin) given intravenously at 5 μg/kg. Plasma samples were taken for cortisol assay before and at 0.5, 1, 2 and 4 h after treatment.
Results Plasma cortisol concentrations were similar with the two ACTH preparations and at both dose rates. Tetracosactrin produced smaller mean peak cortisol concentrations, which tended to occur earlier than with ACTH, and smaller values for the area under the curve of plasma cortisol concentration from zero time to 4 h.
Conclusion The findings suggest that canine adrenal function can be tested adequately by giving ACTH intramuscularly at 1 U/kg and measuring plasma cortisol in samples taken at 0 and 2 h, or by giving tetracosactrin intravenously at 5 μg/kg and determining cortisol concentration at 0 and 1 h.     

水分胁迫对番茄叶片气孔传导及光合色素的影响

以栽培番茄品种AilsaCraig的6叶期幼苗为试验材料,在水培条件下研究了50,75和100g/LPEG水分胁迫对叶片气孔传导、光合色素含量及发叶速度的影响。结果表明,水分胁迫使气孔传导度和发叶速度降低,光合色素增加。气孔传导度和发叶速度的降低均与水分胁迫强度和持续时间有关,而光合色素的增加主要与胁迫持续时间有关。     

Nutrient cycling in a Pinus patula plantation in the Mpumalanga Province, South Africa

The accumulation of litter on the forest floor was identified as a potential problem in managed plantations of Pinus patula (Schlechtd. et Cham.) in the Mpumalanga Province of South Africa in the late 1980s. Litter accumulation in pine plantations is regarded as a threat to site productivity as organic acids are released, moisture penetration is altered and nutrients are immobilised within the litter. This study examines the cycling of nutrients in a 42-year-old P. patula stand in which litter has accumulated. Samples of the vegetation, litter and soil components were collected and chemically analysed for total nitrogen (N), phosphorus (P) and the major cations potassium (K⁺), calcium (Ca²⁺) and magnesium (Mg²⁺). Complete nutrient budgets for N and P, and the cation pool sizes were determined. It was evident from these studies that large reserves of N (1442 kg ha⁻¹) and P (103 kg ha⁻¹) are stored in the litter layers, with levels of cations being low. The presence of large nutrient reserves within the litter and the predominance of fine feeder roots distributed within this layer indicated that a tightly closed plant–litter–plant nutrient cycle was in operation for the cycling of N and P. This may not be true for the major cations. Management of the litter should ensure retention of as many nutrients as possible in the system. This could be achieved through controlled burning to reduce nutrient loss through volatilisation; increasing forest floor temperatures by altering the planting density and application of dolomitic lime to replace cations and to alleviate the acidic conditions making the litter more favourable for decomposing organisms.     

Characteristics, prevalence and aetiology of lesions of the oral mucosa in adult sheep

A total of 214 sheep with lesions of the oral mucosa were recorded at the Veterinary Laboratories Agency regional laboratories between March 15, 2002 and February 28, 2003. Using denominator data from the scrapie abattoir survey a prevalence of 0.95 per cent (95 per cent CI 0.82 to 1.10 per cent) was recorded, and using the fallen stock survey a prevalence of 1.15 per cent (95 per cent CI 0.64 to 1.91 per cent) was recorded. The lesions varied widely and included dental pad lesions in 20 per cent of cases. In total, 248 sites were affected, the commonest being the lower gum below the incisors, which was affected in 100 sheep. Most of the lesions were 1 cm or less in diameter. Ninety per cent of the 251 lesions examined histologically were erosions, ulcers, healed ulcers, focal epithelial necrosis or haemorrhages, and the changes observed indicated that trauma was the most likely primary cause.     

Possible parachordoma in a dog

Abstract

CASE HISTORY: A 15-mm diameter mass developed in the S/C tissue overlying the right lateral gluteal muscle of a 6½-year-old female Flat-coated Retriever.

PATHOLOGICAL FINDINGS: Cytological preparations following aspiration of the mass were highly cellular and consisted of a population of large polygonal cells containing single to multiple nuclei, large prominent nucleoli, and intracytoplasmic vacuoles. Histologically, the neoplasm consisted of similar large cells surrounded by thick fibrous connective tissue trabeculae. The large polygonal cells reacted positively with antibodies against vimentin, low- and high-molecular-weight variants of cytokeratin (AE1/AE3), but not with antibodies to desmin or glial fibrillary acidic protein (GFAP).

DIAGNOSIS: The clinical, gross, histological and immunohistochemical findings are similar to those reported for parachordomas in humans. Neither recurrence nor metastases were noted 18 months after surgical excision of the mass.

CLINICAL RELEVANCE: This is the first reported case of a possible parachordoma in a dog, a benign tumour with cytological features of malignancy.     

Pseudogout in two dogs

Extract

Pseudogout is a common condition in elderly people in which sudden onset of intense joint pain and synovitis develop. Peri-synovial calcium crystal deposition is the cause of the synovitis rather than the uric acid deposition in common gout. It is a rare condition in dogs, having only been reported twice before. Two dogs presenting with acute lameness and pyrexia showed many macrophages and occasional neutrophils containing intracellular crystals on cytological examination of synovial fluid. The crystals were single or multiple, small to large, clear, square or rhomboid-shaped, weakly birefringent and resembled those described for pseudogout. Occasional crystals were also present free in the matrix. Non-steroidal anti-inflammatory drugs that are effective in reducing pain in people with pseudogout provided no relief to either patient, but twice daily oral prednisolone therapy was successful. Dosage was gradually tapered as clinical signs improved over a period of 6 weeks.