Coagulopathic Effects and Therapy of Brodifacoum Toxicosis in Dogs

The clinical signs and laboratory changes of brodifacoum (BDF) intoxicated dogs and their response to vitamin K1 treatment were examined. Brodifacoum, a second-generation anticoagulant rodenticide, was fed to four dogs for 3 consecutive days producing a cumulative dose of 1.1 mg BDF/kg body weight. Clinical observations of the animals were made daily throughout the study. Monitored laboratory parameters included: one-stage prothrombin time (OSPT), activated partial thromboplastin time (APTT), activated coagulation time (ACT), complete blood counts, thrombocyte counts, and serum chemistry values. Response to vitamin K1 therapy was evaluated clinically and by laboratory tests. Serum BDF concentrations were monitored. Inappetence and hemorrhagic tendencies were exhibited by day 5 postrodenticide exposure. One-stage prothrombin time, APTT, and ACT were 25% greater than time zero values at 24, 24, and 72 hours postdosing, respectively. All laboratory parameters returned to normal within 48 hours of initiating vitamin K1 therapy (0.83 mg/kg orally, TID for 5 days). Serum brodifacoum concentrations were highest (1065-1215 ng/mL) during the 3 days after BDF dosing and were detectable (3.0-7.5 ng/mL) until day 24 postexposure. A mean BDF elimination half-life of 6 +/- 4 days was observed.     

Ralstonia solanacearum virulence in tomato seedlings inoculated by leaf clipping

Ralstonia solanacearum is a phytopathogenic bacterium that colonizes the xylem vessels of host plants leading to a lethal wilt disease. Although several studies have investigated the virulence of R. solanacearum on adult host plants, infection studies of this pathogen on the seedling stages of hosts are less common. In a preliminary observation, inoculation of R. solanacearum F1C1 on 6‐ to 7‐day‐old tomato seedlings by a simple leaf‐clip strategy resulted in a lethal pathogenic condition in seedlings that eventually killed these seedlings within a week post‐inoculation. This prompted testing of the effect of this inoculation technique in seedlings from different cultivars of tomato and similar results were obtained. Colonization and spread of the bacteria throughout the infected seedlings was demonstrated using gus‐tagged R. solanacearum F1C1. The same method of inoculating tomato seedlings was used with R. solanacearum GMI1000 and independent mutants of R. solanacearum GMI1000, deficient in the virulence genes hrpB, hrpG, phcA and gspD. Wildtype R. solanacearum GMI1000 was found to be virulent on tomato seedlings, whereas the mutants were found to be non‐virulent. This leaf‐clip technique, for inoculation of tomato seedlings, has the potential to be a valuable approach, saving time, space, labour and costs.     

Biomass and Defoliation Tolerance of 12 Populations of Pseudoroegneria spicata at Two Densities

Pseudoroegneria spicata(Pursh.) A. Löve is an important native grass of the rangelands of the Intermountain West, USA and is widely used in this region for restoration applications. High grazing preference, together with high grazing sensitivity, has reduced the abundance of this species, indicating the need for the development of grazing-tolerant plant materials. While a genotype may be defoliation tolerant at low density, e.g., in an experimental setting, an effective grazing-tolerant genotype must also display this trait at higher densities resembling those found in natural and restoration settings. We compared 12 restoration plant materials for response to spring-defoliation at high (25 plants · m^?2) and low (8 plants · m^?2) plant densities in a field experiment. Two consecutive years of spring-defoliation reduced shoot biomass 19% compared to the nonspring-defoliated control, and this reduction was similar for the two densities examined. Two populations, P-3 and Acc:238, were able to compensate for shoot biomass after 2 yr of spring-defoliation, while the remaining 10 populations undercompensated, as is commonly reported for cool-season grasses in arid and semiarid regions. While the association between control and spring-defoliated shoot biomass was marginally positive (R² = 0.26; P < 0.10), we found a stronger negative association (R² = 0.36; P < 0.05) between spring-defoliation tolerance and control shoot-biomass production. This suggests a possible trade-off between growth and defoliation tolerance (calculated as percentage of control biomass) among populations. Of the four commercially available plant materials in our study, the more recent prevariety germplasm, P-7, exhibited higher control shoot biomass and higher spring-defoliation tolerance than the older cultivars, Whitmar and Goldar. Anatone germplasm was intermediate but not statistically different from these other plant materials for these two traits.