Initiation of Plant Disease Resistance by Physical Interaction of AvrPto and Pto Kinase

Resistance to bacterial speck disease in tomato occurs when the Pto kinase in the plant responds to expression of the avirulence gene avrPto in the Pseudomonas pathogen. Transient expression of an avrPto transgene in plant cells containing Pto elicited a defense response. In the yeast two-hybrid system, the Pto kinase physically interacted with AvrPto. Alterations of AvrPto or Pto that disrupted the interaction in yeast also abolished disease resistance in plants. The physical interaction of AvrPto and Pto provides an explanation of gene-for-gene specificity in bacterial speck disease resistance.     

Effect of seed rate of red clover and of companion timothy or tall fescue on herbage production

Tetraploid red clover (cv. Hungaropoly) was sown at seed rates of 6,12 or 18 kg ha^?1 alone and in mixture with timothy (cv. Scots) at 2, 4 or 6 kg ha^?1 or with tall fescue (cv. S170) at 6,12 or 18 kg ha^?1. Two ‘silage’ crops and an ‘aftermath grazing’ crop were harvested in 2 successive years. In harvest years 1 and 2, total herbage production levels of 11.12 and 7.47 t dry matter (DM) ha^?1 respectively were obtained from pure-sown red clover compared with 11.84 and 8.78 t DM ha^?1 for red clover-timothy and 12.23 and 9.64 t DM ha^?1 for red clover-tall fescue. Corresponding red clover production levels were 10.93 and 5.30 t DM ha^?1 (red clover swards), 8.04 and 3.131 ha^?1 (red clover-timothy), and 6.42 and 109 t ha^?1 (red clover-tall fescue). Total herbage organic matter digestibility was improved by the timothy companion grass but not consistently by the tall fescue, whereas crude protein (CP) concentration was decreased by the addition of either grass. Increased seed rate intensified these effects, as well as the general effect of the companion grass in depressing red clover DM, digestible organic matter (DOM) and CP production. Total herbage DM, DOM and CP were not markedly affected by increasing red clover seed rate but red clover DM, DOM and CP were increased as red clover seed rate was raised, due to increases in the red clover component. The potential for silage cropping of red clover swards was confirmed but there was advantage in sowing a companion grass. Taking yield and quality parameters into consideration, timothy proved a better companion than tall fescue. A seed rate of 2 or 4 kg ha^?1 timothy and 12 kg ha^?1 red clover proved the most satisfactory.     

Benign masses in the pericardium of two dogs

Two miniature Schnauzer dogs were treated for pericardial masses. In one dog the mass consisted of necrotic fat that was attached to the apex of the pericardium by a pedicle. No obvious communication with the abdomen was present. The second dog had a peritoneopericardial hernia associated with a chronic cystic haematoma. In each case the mass was presumed to have arisen following congenital displacement of the omentum into the pericardium. The pericardial mass was removed and subtotal pericardectomy performed in both dogs. Recovery was complete in each case.     

Comparison of Aerobic Culturette, Synovial Membrane Biopsy, and Blood Culture Medium in Detection of Canine Bacterial Arthritis

Canine joints were cultured 24 hours after inoculation with Staphylococcus intermedius using synovial membrane biopsy, synovial fluid on aerobic culturette and in blood culture medium, and synovial fluid incubated 24 hours in blood culture medium before being cultured. A mildly virulent strain consistently yielded positive cultures when incubated in blood culture medium 24 hours and negative cultures with the other techniques. A highly virulent strain also yielded positive cultures when incubated in blood culture medium 24 hours, which was significantly better than synovial membrane biopsy. When both strains were considered together there was no significant difference between the first three techniques; blood culture medium incubated 24 hours was significantly more reliable. These results suggest that the trauma of synovial membrane biopsy is not justified because synovial fluid culture is more reliable. Synovial fluid should be placed on an aerobic culturette and in blood culture medium, and the samples cultured immediately upon arrival at the laboratory to allow the most rapid results of culture and antibiotic sensitivity testing. The blood culture medium should be recultured after 24 hours of incubation to permit culture and antibiotic sensitivity testing of those samples (approximately 50%) that have no growth on initial culture.     

Use of a modified open patch-graft technique and valvulectomy for correction of severe pulmonic stenosis in dogs: eight consecutive cases

SUMMARY A modified open patch-graft technique was used to correct congenital pulmonic stenosis in 8 dogs. Pulmonary valve dysplasia was moderate to severe in all cases, based upon clinical and echocardiographic criteria, and 3 dogs were in right-sided congestive heart failure at the time of surgery. Seven of the 8 dogs survived the surgery. One surviving dog displayed cerebral cortical dysfunction, the remaining 6 had no detectable neurological sequelae. Right ventricular failure was alleviated in all 7 surviving dogs, but right ventricular dilatation persisted post-operatively. Pulmonary valvulectomy and open patch-grafting provides an effective means of alleviating signs of congestive heart failure caused by pulmonary valve dysplasia, even In the presence of severe infundibular hypertrophy and dynamic outflow obstruction.     

Sutured End-to-End and Stapled Side-to-Side Jejunal Anastomoses in the Horse

Hand sutured end-to-end (EE) and stapled side-to-side (SS) small intestinal anastomoses were performed in 10 healthy adult horses. In five SS anastomoses, staple lines on the blind ends of the jejunum were inverted (SSI) and in five they were not (SSNI). Five EE anastomoses were sutured with polydioxanone and five were sutured with polyglyconate. All horses were euthanatized on day 30. Intra-abdominal adhesions were graded (0-4), and stomal areas were calculated from contrast radiographs made with the bowel distended. Histopathology scores for the anastomoses were based on the degree of inflammation (0-3), fibrosis (0-3), and alignment and healing of intestinal layers (0-3). Mean surgery times +/- standard deviations for EE, SSI, and SSNI techniques were 33.9 +/- 5.4, 36.2 +/- 5.6, and 29.6 +/- 5.9 minutes, respectively. Mean and median stomal areas were 9.4 +/- 5.5 and 8.9 cm2 for EE anastomoses and 17.2 +/- 16.5 and 12.1 cm2 for SS anastomoses. Intra-abdominal adhesions developed in three horses, one of which had clinical signs of colic. Mean histopathology scores for EE and SS anastomoses were 4.8 +/- 2.0 (median = 5) and 4.4 +/- 1.8 (median = 4), respectively. There were no statistically significant differences in surgery times, intra-abdominal adhesion scores, stomal areas, or histopathology scores between small intestinal EE and SS anastomoses in these horses.     

Pharmacokinetics of theophylline in swine: a potential model for human drug bioavailability studies

The pharmacokinetics of theophylline in swine were investigated following die oral and intravascular administration of single doses of theophylline free base. The mean half-life of theophylline following intravascular administration was 11.0 h, and the apparent specific volume of distribution was 0.61 liter/kg. Following oral administration, theophylline in solution was absorbed quite rapidly with a bioavailability of 79%. The similarity of the pharmacokinetics of theophylline in swine and humans suggests that swine may provide a useful model for the study of the bioequivalency of theophylline dosage forms intended for human use. The pharmacokinetic characteristics of theophylline also favor its consideration for usage as a therapeutic agent in swine.     

The effect of prostaglandin E1 on motility of the equine gut

Prostaglandin E1 was infused intravenously (25, 50 and 75 ng/kg/min) in three ponies. Changes in gastrointestinal mechanical and electrical activity were recorded from chronically implanted strain-gauge force transducers and electrodes. Dose-dependent responses were obtained: there were significant decreases in electrical spiking activity in the stomach, left large colon and small colon, with a corresponding decrease of activity in the left dorsal colon mechanogram. The small intestine was also affected, showing a decrease in both contraction rate and amplitude, which was more marked in the proximal jejunum than in the ileum. There was an association between these changes in gastrointestinal activity and the presence of discomfort and diminished gut sounds.