Major gene resistance in Brassica napus (oilseed rape) is overcome by changes in virulence of populations of Leptosphaeria maculans in France and Australia

Resistance of Brassica napus (oilseed rape, canola) conferred by three different major resistance genes has been overcome by changes in virulence of Leptosphaeria maculans populations in France and Australia. In South Australia where B. napus cultivars with major gene resistance derived from Brassica rapa ssp. sylvestris were grown extensively, resistance was rendered ineffective within 3 years of commercial release of the cultivar. Disease severity was higher on cultivars with sylvestris-derived resistance than cultivars with polygenic resistance. This Australian situation is compared to that in France, where resistance conferred by the Rlm1 gene was overcome nation-wide in 5 years under commercial cropping practices, and also where a source of resistance introgressed into B. napus from B. juncea was rendered inefficient in 3 years in experimental field plots near Rennes.     

Syncope secondary to transient atrioventricular block in a German shepherd dog with dilated cardiomyopathy and atrial fibrillation

This case report describes transient atrioventricular block as the etiology for syncopal events in a 6-year-old male German shepherd dog with atrial fibrillation and dilated cardiomyopathy. The arrhythmia diagnosis was obtained via Holter monitoring. Medical treatment with a sustained-release preparation of theophylline, as an additive to the standard congestive heart failure treatment (benazepril, furosemide and pimobendan) may have contributed to temporary remission of the syncopal events. However, the congestive heart failure progressed and the dog was euthanized. Veterinarians should be aware of the possibility of transient atrioventricular block causing syncope in dogs with DCM and AF and should be careful in empirically lowering the ventricular response rate if these dogs present with syncopal episodes.     

Influence of growing season and donor plant age on anther culture response of some pepper cultivars (Capsicum annuum L.)

The effects of growing season and donor plant age on anther culture in Capsicum were investigated. Pepper cultivars Kekova and Sera Demre 8 were grown under unheated greenhouse conditions in winter season and field conditions in summer season. Flower buds were collected and cultured in weekly intervals from November to May in winter and from April to December in summer. The results of this study indicated that anthers from these two pepper genotypes gave different embryogenic response to seasonal effects. Kekova cultivar gave the highest embryogenic yield in summer season while this was occurred in winter season for Sera Demre 8 cultivar. The results of the study revealed that the effect of donor plant age was also an important factor in anther culture of pepper. Since 4-month-old plants gave the highest embryo yield in both cultivars in each seasons, it is possible to say that anthers collected from old plants have sufficient embryogenic response when the optimum developmental stage is selected.     

AFLP analysis of genetic diversity in low chill requiring walnut (Juglans regia L.) genotypes from Hatay,Turkey

In this study, the genetic relatedness of 22 low chill requiring walnut genotypes adapted to the south east Mediterranean region of Turkey was analysed by amplified fragment length polymorphism (AFLP) markers. Relatively low level of genetic variation was detected among the genotypes examined by five AFLP primer combinations, suggesting that these walnut genotypes selected predominantly for their low chill requirement have relatively narrow genetic base. In addition, the geographical proximity of the genotypes analysed was not correlated with their level of genetic relatedness. These results have implications for walnut breeding and conservation.     

The fatty acid profile of subcutaneous fat and blood plasma in pruritic dogs and dogs without skin problems.

The purpose of this study was to investigate the concentration of polyunsaturated fatty acids (PUFAs) in subcutaneous fat and the relative amounts of PUFAs in plasma in two groups of dogs. Group 1 included dogs with a good skin and coat condition. Group 2 was comprised of dogs with pruritus and compatible clinical signs of atopy. The fatty acid composition of the total lipid fraction was analyzed by gas chromatography. In subcutaneous fat, the concentration of adrenic acid (22:4n-6) was lower in the group of pruritic dogs compared to dogs with healthy skin. The amount of dihomogammalinolenic acid (20:3n-6; DGLA) in plasma lipids from pruritic dogs was higher than in dogs without skin problems.     

The effect of selected preparations for the protection of draft horses against dipterous blood-sucking insects

Dipterous blood-sucking insects (horseflies, black flies, gnats, midges) have negative impacts on the performance of draught horses in forest enterprises. For the protection of these animals, the following preparations were applied at the interval of 24 hours: diethyltoluamide, Oxamat (N,N-diethyloxamine acid, USSR) and Stomoxin (synthetic pyrethroid, product of the firm Wellcome, England). In the course of 66 working days, the performance of test animals treated with 10% water emulsion of diethyltoluamide increased by 49.25 cu. m. of skidded wood, i.e. by 0.74 cu. m. wood per horse/day (21.65%), as compared with the control group. The daily savings of prime costs per test horse/day made 16.99 Kcs (Czechoslovak crowns). In comparison with the control group, the performance of horses treated with 5% water emulsion of Oxamat increased by 85.50 cu. m. wood, i.e. by 1.29 cu. m. wood per horse/day (38.00%). Stomoxin at the concentration of 0.05% acted as a good insecticide but had no marked repellent effect. The results of this study document that the production of effective repellents should be introduced in the Czechoslovak Socialist Republic.     

Pharmacokinetics and cardiopulmonary effects of guaifenesin in donkeys

Five donkeys and three horses were given guaifenesin, intravenously, by gravity administration, until recumbency was produced. The time and dose required to produce recumbency, recovery time to sternal and standing were recorded. Blood samples were collected for guaifenesin assay at 10, 20, 30, 40, 50, 60 min, and 2, 3, 4 and 6 h after guaifenesin administration. Serum was analysed for guaifenesin using HPLC and pharmacokinetic values were calculated using a computer software package (RSTRIP). In donkeys, heart and respiratory rates and blood pressures were recorded before and at 5-min intervals during recumbency. Arterial blood samples were collected before and at 5 and 15 min intervals during recumbency for analysis of pH, CO₂, and O₂. anova was used to evaluate dynamic data, while t -tests were used for kinetic values.
Respiratory rate was decreased significantly during recumbency, but no other significant changes from baseline occurred. The mean (±SD) recumbency dose of guaifenesin was 131 mg/kg (27) for donkeys and 211 mg/kg (8) for horses. Recovery time to sternal (min) was 15 (SD, 11) for donkeys and 34 (SD, 1.4) for horses. Time to standing was 32 min for donkeys and 36 min for horses. Calculation of AUC (area under the concentration–time curve) (μg.h/mL) (dose-dependent variable) was 231 (SD, 33) for donkeys and 688 (SD, 110) for horses. The clearance ( CL ) (mL/h.kg) was 546 (SD, 73) for donkeys, which was significantly different from 313 (SD, 62) for horses. Mean residence time ( MRT ) (h) was 1.2 (SD, 0.1) for donkeys and 2.6 (SD, 0.5) for horses. Volume of distribution V _d(area) (mL/kg) was 678 (SD, 92) for donkeys and 794 (SD, 25) for horses. At the rate of administration used in this study, donkeys required less guaifenesin than horses to produce recumbency, but cleared it more rapidly.     

The effect of compression and incision on wood veneer and plywood physical and mechanical properties

ABSTRACT

Drying takes the largest share of energy in plywood production, and varying moisture content of veneers necessitates re-drying that often leads to over-dry veneers with deactivated surfaces, which may promote imperfect bonding. In order to decrease the drying time, reduce the need for re-drying of veneers, and improve the quality of plywood, birch and spruce veneers were subjected to pre-treatment by cold compression, incision, or a combination of the two. The effects of pre-treatment on the veneer and plywood quality were assessed by standard tests. Compression had a beneficial effect on water removal of the wettest veneers (spruce sapwood (SW) and birch), but some thickness reduction was observed in the veneers as well as the finished birch plywood. Compression led to thickness reduction of spruce veneers, but had no effect on SW plywood thickness likely due to higher viscoelasticity. Both compression and the combination of incising and compression levelled the moisture variation within the compressed stacks. Incision improved the modulus of elasticity of birch plywood, shear strength of SW plywood, and both bending and shear strengths of heartwood plywood. Higher surface pressure decreased the drying time of spruce SW in both plain compression and combined incision and compression pre-treatment.     

Shoot development and dieback in progenies of Nothofagus obliqua

Shoot growth and dieback were compared among progenies of nursery-grown seedlings of Nothofagus obliqua belonging to seven progenies of the same provenance (Quila-Quina, Argentina). First-year shoots consisted of one growth unit (GU) and second-year shoots of one or two GUs. The probability of development of two GU was similar for all progenies. Progenies were different in terms of shoot size, terminal bud abscission, the extent of shoot dieback after shoot extension and the node of origin of the relay shoot on the first shoot. Plants with a second-year shoot consisting of two GUs had a thicker stem and more nodes than those with single-GU shoots. The selection of N. obliqua seed trees based on architectural traits suitable for forestry development at specific sites must contemplate variability among progenies and their probabilities of successful development under different conditions.