Comparative analysis of the cold acclimation and freezing tolerance capacities of seven diploid Brachypodium distachyon accessions.

BACKGROUND AND AIMS: Cold is a major constraint for cereal cultivation under temperate climates. Winter-hardy plants interpret seasonal changes and can acquire the ability to resist sub-zero temperatures. This cold acclimation process is associated with physiological, biochemical and molecular alterations in cereals. Brachypodium distachyon is considered a powerful model system to study the response of temperate cereals to adverse environmental conditions. To date, little is known about the cold acclimation and freezing tolerance capacities of Brachypodium. The main objective of this study was to evaluate the cold hardiness of seven diploid Brachypodium accessions. METHODS: An integrated approach, involving monitoring of phenological indicators along with expression profiling of the major vernalization regulator VRN1 orthologue, was followed. In parallel, soluble sugars and proline contents were determined along with expression profiles of two COR genes in plants exposed to low temperatures. Finally, whole-plant freezing tests were performed to evaluate the freezing tolerance capacity of Brachypodium. KEY RESULTS: Cold treatment accelerated the transition from the vegetative to the reproductive phase in all diploid Brachypodium accessions tested. In addition, low temperature exposure triggered the gradual accumulation of BradiVRN1 transcripts in all accessions tested. These accessions exhibited a clear cold acclimation response by progressively accumulating proline, sugars and COR gene transcripts. However, whole-plant freezing tests revealed that these seven diploid accessions only have a limited capacity to develop freezing tolerance when compared with winter varieties of temperate cereals such as wheat and barley. Furthermore, little difference in terms of survival was observed among the accessions tested despite their previous classification as either spring or winter genotypes. CONCLUSIONS: This study is the first to characterize the freezing tolerance capacities of B. distachyon and provides strong evidence that some diploid accessions such as Bd21 have a facultative growth habit.

Efficacy of a paste formulation of omeprazole for the treatment of naturally occurring gastric ulcers in training standardbred racehorses in Canada.

The efficacy of a paste formulation of the H+, K+, -ATPase inhibitor omeprazole was evaluated in standardbred racehorses for the treatment and prevention of gastric ulcers. Twenty standardbred racehorses in training, aged 2 to 9 years, were enrolled from 2 training centres in this field trial. Endoscopic examinations confirmed the presence of gastric ulcers in all horses, prior to allocation and treatment and on day 0. Lesions were scored on a scale of 0 to 3 (intact epithelium to extensive ulceration). Replicates were formed, based on training level and location. Within replicates, 1 horse was assigned to group 1 and 3 horses were assigned to group 2, randomly. Horses in group 1 were sham-dosed controls. Horses in group 2 were given omeprazole paste orally at 4 mg/kg bodyweight (BW)/day from day 0 to day 27 and 2 mg/kg BW/day of omeprazole paste orally from day 28 to day 57. Follow-up endoscopies were conducted on post treatment days 28 and 58 or 59. Physical examinations, including BWs, were conducted on all horses prior to treatment and on days 13 or 14, 28, 42 or 43, and 58 or 59. Horses treated with omeprazole had significantly (P < 0.01) more improvement in gastric lesion scores than did controls at day 28 and at study termination on days 58 or 59. All of the omeprazole-treated horses were improved relative to baseline ulcer score at both examinations, and 73.3% were healed (lesion score of 0) at both examinations. None of the controls improved at any point during the study. When the dose was reduced to 2 mg/kg BW, 80% of the horses showed no recurrences or worsening in gastric ulcers. It was concluded that omeprazole paste at 4 mg/kg BW orally, once daily is highly effective in healing gastric ulcers in standardbred racehorses in training and that a dose of 2 mg/kg BW orally, once daily, effectively prevents the recurrence of gastric ulcers in most horses.

Gastric ulcers in standardbred racehorses: prevalence, lesion description, and risk factors.

This study was performed to estimate the prevalence of gastric ulcers in Standardbred racehorses, to describe the lesion score and location, and to identify potential risk factors. Two hundred seventy-five (275) Standardbred horses from 5 training centers and 2 racetracks in Quebec, Canada, were studied. Historical data for the 2 months before examination were recorded for each horse, and the presence of gastric ulcers was determined by gastroscopy. A previously reported scoring system that used grades 0-3 for gastric lesions was used. Overall, 121 horses (44.0%; 95% CI, 38.1-50.1%) had gastric ulcers. The prevalence of gastric ulcers was significantly higher (P < .0001) in actively racing horses (63.3%; 95% CI, 54.7-71.2%) than in horses at rest. Multivariate analysis defined that horses in racing (OR = 9.29; 95% CI, 3.55-24.3) were significantly more likely to have gastric ulcers than horses at rest and that trotters (OR = 2.23; 95% CI, 1.28-3.86) were more likely to have gastric ulcers than pacers. The number of lesion sites (P < .0001) and poor body condition (P < .0001) were significantly associated with lesion scores. Gastric ulcers are highly prevalent in Standardbred racehorses. Furthermore, actively racing horses and trotters are more likely to have gastric ulcers. Also, poor body condition in Standardbred racehorses may be an indication that gastric ulcers are present and that lesion scores are high. The cause-and-effect relationship between poor body condition and the presence of gastric ulcers is unclear.