Non-target toxicology of a new mosquito larvicide, trypsin modulating oostatic factor

Trypsin modulating oostatic factor (TMOF), a peptide hormone originally isolated from the ovaries of adult Aedes aegypti, is currently under commercial development as a new pesticide chemistry with a novel mode of action for the control of larval mosquitoes. The objective of the current research is to evaluate potential risks of the use of TMOF as an insecticide on non-target organisms. TMOF (YDPAP₆) was degraded in vitro (as determined by HPLC and LC/MS) to DPAP₆, PAP₆, and then AP₆ by leucine aminopeptidase, a pancreatic enzyme found in the digestive system of vertebrates. The rate of degradation of TMOF and PAP₆ was significantly greater than that of DPAP₆, while no metabolism of AP₆ was found. TMOF technical insecticide was produced on a commercial scale by recombinant yeast (heat-killed before application). The technical TMOF when administered in a single dose by gavage to male and female mice at 2000 mg dry weight/kg body weight produced no negative effects as compared to controls up to 12 days after treatment. When male and female mallard ducks were treated by gavage with 1250 mg dry weight of technical TMOF/kg body weight each day for 5 days, again no toxic effects were noted through 35 days after the last treatment. TMOF technical insecticide was also applied to the shaved skin of male and female rabbits at the rate of 2000 mg/kg for 1-2 days, with no effect. The end point observations in these in vivo experiments were mortality; changes in growth rate, behavior, body structure, and color; and possible lesions observed during necropsy. Finally, Daphnia incubated with technical TMOF in rearing water at the level of 1.0 × 10⁶ yeast cells/ml (10 mg/ml) also demonstrated no negative effects on mortality, growth, molting, time to first brood, and production of viable neonates. It appears from these studies that TMOF can be degraded by vertebrate digestive proteases and technical TMOF is not toxic to the non-target organisms examined.     

Molecular determinants of scouting behavior in honey bees

Little is known about the molecular basis of differences in behavior among individuals. Here we report consistent novelty-seeking behavior, across different contexts, among honey bees in their tendency to scout for food sources and nest sites, and we reveal some of the molecular underpinnings of this behavior relative to foragers that do not scout. Food scouts showed extensive differences in brain gene expression relative to other foragers, including differences related to catecholamine, glutamate, and γ-aminobutyric acid signaling. Octopamine and glutamate treatments increased the likelihood of scouting, whereas dopamine antagonist treatment decreased it. These findings demonstrate intriguing similarities in human and insect novelty seeking and suggest that this trait, which presumably evolved independently in these two lineages, may be subserved by conserved molecular components.     

Bold fusion: transtracheal wash from a Jersey calf

A 10-week-old, female, Jersey calf was referred to the University of Minnesota Veterinary Medical Center for evaluation of difficult breathing and inappetence of 18-hours duration. Cytologic examination of a transtracheal wash specimen revealed pyogranulomatous inflammation, with increased numbers of multinucleated cells. Differential diagnoses included established bacterial infection, viral infection, fungal infection, and foreign body reaction. Immunocytochemical staining was done on a direct smear of the transtracheal wash using a cocktail of 4 mouse monoclonal antibodies against 3 human respiratory syncytial virus proteins. Strong intracytoplasmic staining within mononuclear cells was observed and a diagnosis of bovine respiratory syncytial virus infection was made. Immunocytochemistry may be used as a rapid, inexpensive, adjunctive diagnostic tool for the antemortem diagnosis of bovine respiratory syncytial virus on transtracheal wash specimens.     

Effects of constant rate infusions of dexmedetomidine or MK-467 on the minimum alveolar concentration of sevoflurane in dogs

Objective

To determine the effects of low and high dose infusions of dexmedetomidine and a peripheral α₂-adrenoceptor antagonist, MK-467, on sevoflurane minimum alveolar concentration (MAC) in dogs.

Safety and efficacy of high‐dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats

Objective – To determine the safety and efficacy of high‐dose fomepizole compared with ethanol (EtOH) in cats with ethylene glycol (EG) toxicosis. Design – Prospective study. Setting – University veterinary research laboratory. Animals – Thirteen cats. Interventions – Two cats received injections of high‐dose fomepizole (Study 1). Three cats received lethal doses of EG and fomepizole treatment was initiated 1, 2, or 3 hours later (Study 2). Eight cats received a lethal dose of EG and were treated with fomepizole or EtOH (Study 3). Cats treated with fomepizole received 125 mg/kg IV initially, then 31.25 mg/kg at 12, 24, and 36 hours. Cats treated with EtOH received 5 mL of 20% EtOH/kg IV initially, then every 6 hours for 5 treatments, then every 8 hours for 4 treatments. Cats also received fluids and supportive therapy as needed. Measurements and Main Results – Clinical signs were monitored and serial blood analyses performed. Cats receiving fomepizole experienced mild sedation but no biochemical evidence of toxicity. Cats receiving fomepizole for EG intoxication survived if therapy was initiated within 3 hours of EG ingestion. One of the 6 developed acute renal failure (ARF) but survived. Only 1 of the 3 cats treated with EtOH 3 hours following EG ingestion survived; 2 developed ARF and were euthanized. Cats treated 4 hours following EG ingestion developed ARF, whether treated with EtOH or fomepizole. Conclusions – Fomepizole is safe when administered to cats in high doses, prevents EG‐induced fatal ARF when therapy is instituted within 3 hours of EG ingestion, and is more effective than treatment with EtOH.