A Cluster of Major Specific Resistance Genes to Leptosphaeria maculans in Brassica napus

ABSTRACT Two types of genetic resistance to Leptosphaeria maculans usually are distinguished in Brassica napus: qualitative, total resistance expressed at the seedling stage and quantitative, partial resistance expressed at the adult plant stage. The latter is under the control of many genetic factors that have been mapped through quantitative trait loci (QTL) studies using 'Darmor' resistance. The former usually is ascribed to race-specific resistance controlled by single resistance to L. maculans (Rlm) genes. Three B. napus-originating specific Rlm genes (Rlm1, Rlm2, and Rlm4) previously were characterized. Here, we report on the genetic identification of two novel resistance genes, Rlm3 and Rlm7, corresponding to the avirulence genes AvrLm3 and AvrLm7. The identification of a novel L. maculans- B. napus specific interaction allowed the detection of another putative new specific resistance gene, Rlm9. The resistance genes were mapped in two genomic regions on LG10 and LG16 linkage groups. A cluster of five resistance genes (Rlm1, Rlm3, Rlm4, Rlm7, and Rlm9) was strongly suggested on LG10. The relation between all these specific resistance genes and their potential role in adult-plant field resistance is discussed. These two Rlm-carrying regions do not correspond to major QTL for Darmor quantitative resistance.     

Pesticide residues in the total diet in Canada. III—1971

Foods, representing an average Canadian diet, were cooked, grouped by type of product and made into composites which were then analysed for organochlorine and organophosphorus pesticides and arsenic. The amounts found were at a consistently low level and would contribute approx. 22 μg total pesticide residues and 25 μg arsenic/person/day.     

Comparative study of three intramuscular anaesthetic combinations (medetomidine/ketamine, medetomidine/fentanyl/midazolam and xylazine/ketamine) in rabbits

OBJECTIVE: To compare the quality of surgical anaesthesia and cardiorespiratory effects of three intramuscular (IM) anaesthetic combinations in rabbits. STUDY DESIGN: Prospective randomized cross-over experimental study. ANIMALS: Nineteen adult female chinchilla mixed-bred rabbits weighing 3.9 +/- 0.8 kg. METHODS: Rabbits were given one of three IM anaesthetic combinations: 0.25 mg kg(-1) medetomidine and 35.0 mg kg(-1) ketamine (M-K), 0.20 mg kg(-1) medetomidine and 0.02 mg kg(-1) fentanyl and 1.0 mg kg(-1) midazolam (M-F-Mz) and 4.0 mg kg(-1) xylazine and 50 mg kg(-1) ketamine (X-K). The effects of anaesthesia on nociceptive reflexes, circulatory and respiratory function were recorded. Statistical analyses involved repeated measures anova with paired Student's t-test applied post hoc. P-values <0.05 were considered as significant. RESULTS: Reflex loss was most rapid and complete in M-K recipients, whereas animals receiving M-F-Mz showed the longest tolerance of endotracheal intubation (78.1 +/- 36.5 minutes). Loss of righting reflex was significantly most rapid (p < 0.05) in the X-K group (114.7 +/- 24.0 minutes). Surgical anaesthesia was achieved in 16 of 19 animals receiving M-K, in 14 animals receiving M-F-Mz, and in seven animals with X-K, but only for a short period (7.1 +/- 11.6 minutes). This was significantly (p < 0.001) shorter than with M-K (38.7 +/- 30.0 minutes) and M-F-Mz (31.6 +/- 26.6 minutes). Heart rates were greatest in X-K recipients; lowest HR were seen in animals receiving M-F-Mz. Mean arterial blood pressure was significantly higher (about 88 mmHg) during the first hour in the M-K group. During recovery, the greatest hypotension was encountered in the X-K group; minimum values were 53 +/- 12 mmHg. Six of 19 animals in the M-F-Mz group showed a short period of apnoea (30 seconds) immediately after endotracheal intubation. Respiratory frequency was significantly lower in this group (p < 0.001). Highest values for arterial carbon dioxide partial pressures (PaCO(2)) (6.90 +/- 0.87 kPa; 52.5 +/- 6.5 mmHg) occurred after induction of anaesthesia in group M-F-Mz animals. There was a marked decrease in PaO(2) in all three groups (the minimum value 5.28 +/- 0.65 kPa [39.7 +/- 4.9 mmHg] was observed with M-K immediately after injection). Arterial PO(2) was between 26.0 and 43.0 kPa (196 and 324 mmHg) in all groups during O(2) delivery and decreased - but not <7.98 kPa - on its withdrawal. Immediately after drug injection, pH(a) values fell in all groups, with lowest values after 30 minutes (7.23 +/- 0.03 with M-K, 7.28 +/- 0.05 with M-F-Mz, and 7.36 +/- 0.04 with X-K). The X-K animals showed significantly (p < 0.001) higher pH values than medetomidine recipients. During 1 hour of anaesthesia pH values in the medetomidine groups remained below those of the X-K group. CONCLUSIONS: Surgical anaesthesia was induced in most animals receiving medetomidine-based combinations. Arterial blood pressure was maintained at baseline values for about 1 hour after M-K. Transient apnoea occurred with M-F-Mz and mandates respiratory function monitoring. Oxygen enrichment of inspired gases is necessary with all three combinations. Endotracheal intubation is essential in rabbits receiving M-F-Mz. CLINICAL RELEVANCE: The quality of surgical anaesthesia was greatest with M-K. All combinations allowed recoveries of similar duration. It is theoretically possible to antagonize each component of the M-F-Mz combination.     

Identification of RAPD markers linked to linolenic acid genes in rapessed

Summary The inheritance of the low linolenic acid content (derivated from mutant lines) in rapeseed was investigated. Molecular techniques of gene mapping through RAPD markers were applied on a microspore-derived progeny from a high × low linolenic acid F₁ hybrid. Bulked segregant analysis made it possible to test rapidly number of RAPD primers. Two linkage groups of 6 markers (72.7 cM and 75.6 cM) were determined. Each corresponded to a major QTL which explained 24% and 30.7% of the total phenotypic variation of the linolenic acid content. It was confirmed that two independant mutations were implied in the low linonenic acid content.     

Pesticide residues in the total diet in Canada. IV. 1972 and 1973

Foods, representing an average Canadian diet, were prepared for eating, made into homogenised composites, each containing one type of produce, and analysed for pesticide residues and arsenic. The amounts found were at a consistently low level which could contribute approximately 20 μg total pesticide residues and 35 μg arsenic/person/day.     

Clinical evaluation of three medetomidine--midazolam--ketamine combinations for neutering of ferrets (Mustela putorius furo)

33 ferrets (Mustela putorius furo, 11 females, 22 males, ASA I-II) were neutered in a combination anaesthesia with medetomidine, midazolam and ketamine. The animals were randomized into 3 groups. All animals received 20 microg/kg BW medetomidine and 0.5 mg/kg BW midazolam. The three groups differed regarding dosis and way of application of ketamine (IM10 = 10 mg/kg BW intramuscularly; IM07 = 7 mg/kg BW intramuscularly; SC10 = 10 mg/kg BW subcutaneously). After 30 minutes anaesthesia was partially antagonised with 100 microg/kg BW atipamezole i.m.. Sedation, muscle relaxation, analgesia, and overall anaesthetic impression were compared by a scoring protocol. Reactions to painful stimuli of clamping the spermatic cord or the ovarial ligament including the A. ovarica were judged, too. All animals lost their righting reflex and could be placed in dorsal recumbency. Induction and recovery time were significantly the shortest in study group IM10 with 1.73 +/- 0.3 and 9.73 +/- 4.6 min respectively. Recovery was significantly prolonged in group SC10 with 30.27 +/- 15.6 min. The MMK-anaesthesia with 10 mg/kg ketamine i.m. is very useful for neutering ferrets. Respiratory depression and bradycardia typically for medetomidine were seen in all three combinations, but quickly reversed after partial antagonisation. Induction and intubation, followed by inhalation anaesthesia, were possible with all three regimes.