Mycobacteriosis in an American bald eagle (Haliaeetus leucocephalus)

Avian mycobacteriosis is an important disease in companion, captive, exotic, and wild birds worldwide. Mycobacterium avium is the most widely distributed and pathogenic organism causing tuberculous lesions in birds. Multiple factors including age, stress, immune status, and preexisting disease determine the pathogenicity of M. avium, and the disease can manifest itself in a variety of forms. Mycobacteriosis can cause severe losses in zoo aviaries, including the loss of rare and endangered bird species. We report a case of systemic avian mycobacteriosis in an adult, free-living male American bald eagle (Haliaeetus leucocephalus) that presented to the Diagnostic Center for Population and Animal Health in November 2003.     

Molecular characterization of a stable antisense chalcone synthase phenotype in strawberry (Fragaria x ananassa)

An octaploid (Fragaria x ananassa cv. Calypso) genotype of strawberry was transformed with an antisense chalcone synthase (CHS) gene construct using a ripening related CHS cDNA from Fragaria x ananassa cv. Elsanta under the control of the constitutive CaMV 35S promoter via Agrobacterium tumefaciens. Out of 25 transgenic lines, nine lines showed a reduction in CHS mRNA accumulation of more than 50% as compared to the untransformed cv. Calypso control. The antisense CHS construct was found to be integrated into the genome, with a copy number ranging from one to four. The pigmentation of the fruit was only affected when less than 5% of the control CHS expression level was detected. A stable antisense phenotype over a period of 4 years was obtained in the primary transgenic lines at a rate of 1:20. As a consequence of the reduced activity of CHS, the levels of anthocyanins, flavonols, and proanthocyanidins were downregulated and precursors of the flavonoid pathway were shunted to the phenylpropanoid pathway leading to highly increased levels of cinnamoyl glucose (520% of control), caffeoyl glucose (816% of control), and feruloyl glucose (1092% of control) as well as p-coumaryl alcohol (363% of control) and p-coumaryl-1-acetate (1079% of control), which occur only as trace components in untransformed control fruits. These results demonstrate that the introduction of an antisense CHS construct in strawberry results in an unpredictable biochemical phenotype, thereby confirming that CHS function is an important regulatory point of substrate flow between the flavonoid and the phenylpropanoid pathways.     

Airway inflammation is associated with mucous cell metaplasia and increased intraepithelial stored mucosubstances in horses

This study was performed to determine if a peripheral sample of lung from the site where biopsy is conducted is representative of the rest of the lung and to investigate the relationship between airway inflammation and intraepithelial mucous production in the peripheral airways. Lung parenchyma samples were collected from five different regions of the lung in five control and five heaves-affected horses. Horse groups were defined by clinical response to stabling. Tissue sections were used for semi-quantitative scoring of lesions, to count the number of airways, to quantify the amount of stored mucosubstances (Vs) within the epithelium, and to count the number of epithelial cells in terminal airways. No significant differences were found between lung regions or between groups of horses. Lack of regional differences in airway structures means that a biopsy sample can be used for diagnosis and investigation of diffusely distributed diseases. Airway inflammation was correlated with mucous cell metaplasia and Vs. Therefore, in horses, mucus accumulation is partly caused by increased number of mucous cells and is associated with airway inflammation. Therapy targeted to reduce airway inflammation will help reduce the excessive mucous accumulation in horses.     

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.     

What size is a biologically relevant landscape?

The spatial extent at which landscape structure best predicts population response, called the scale of effect, varies across species. An ability to predict the scale of effect of a landscape using species traits would make landscape study design more efficient and would enable landscape managers to plan at the appropriate scale. We used an individual based simulation model to predict how species traits influence the scale of effect. Specifically, we tested the effects of dispersal distance, reproductive rate, and informed movement behavior on the radius at which percent habitat cover best predicts population abundance in a focal area. Scale of effect for species with random movement behavior was compared to scale of effect for species with three (cumulative) levels of information use during dispersal: habitat based settlement, conspecific density based settlement, and gap-avoidance during movement. Consistent with a common belief among researchers, dispersal distance had a strong, positive influence on scale of effect. A general guideline for empiricists is to expect the radius of a landscape to be 4?C9 times the median dispersal distance or 0.3?C0.5 times the maximum dispersal distance of a species. Informed dispersal led to greater increases in population size than did increased reproductive rate. Similarly, informed dispersal led to more strongly decreased scales of effect than did reproductive rate. Most notably, gap-avoidance resulted in scales that were 0.2?C0.5 times those of non-avoidant species. This is the first study to generate testable hypotheses concerning the mechanisms underlying the scale at which populations respond to the landscape.     

The effects of yohimbine on the pharmacokinetic parameters of detomidine in the horse

ObjectiveTo describe the pharmacokinetics of detomidine and yohimbine when administered in combination.Study designRandomized crossover design.AnimalsNine healthy adult horses aged 9 ± 4 years and weighing of 561 ± 56 kg.MethodsThree dose regimens were employed in the current study. 1) 0.03 mg kg^?1 detomidine IV (D), 2) 0.2 mg kg^?1 yohimbine IV (Y) and 3) 0.03 mg kg^?1 detomidine IV followed 15 minutes later by 0.2 mg kg^?1 yohimbine IV (DY). Each horse received all three dose regimens with a minimum of 1 week in between subsequent regimens. Blood samples were obtained and plasma analyzed for detomidine and yohimbine concentrations by liquid chromatography-mass spectrometry. Data were analyzed using both non-compartmental and compartmental analysis.ResultsThe maximum measured detomidine concentrations were 76.0 and 129.9 ng mL^?1 for the D and DY treatments, respectively. Systemic clearance and volume of distribution of detomidine were not significantly different for either treatment. There was a significant increase in the maximum measured yohimbine plasma concentrations from Y (173.9 ng mL^?1) to DY (289.8 ng mL^?1). Both the Cl and V_d for yohimbine were significantly less (6.8 mL minute^?1 kg^?1 (Cl) and 1.7 L kg^?1 (V_d)) for the DY as compared to the Y treatments (13.9 mL minute^?1 kg^?1 (Cl) and 2.7 L kg^?1 (V_d)). Plasma concentrations were below the limit of quantitation (0.05 and 0.5 ng mL^?1) by 18 hours for both detomidine and yohimbine.Conclusion and clinical relevanceThe Cl and V_d of yohimbine were affected by prior administration of detomidine. The elimination half life of yohimbine remained unaffected when administered subsequent to detomidine. However, the increased plasma concentrations in the presence of detomidine has the potential to cause untoward effects and therefore further studies to assess the physiologic effects of this combination of drugs are warranted.     

Critical care monitoring considerations for the diabetic patient

Diabetes mellitus (DM) is a common endocrine disease encountered in the emergency and critical care setting. The diabetic Ketoacidotic (DKA) animal represents an extreme of the DM patient with regard to hyperglycemia and acid-base and electrolyte derangements. Prompt diagnosis of DKA in a critical patient and rapid initiation of appropriate therapy are necessary for a positive outcome. The steps of treatment, in order of importance, include initiation of intravenous fluid therapy, insulin therapy, electrolyte replacement, and reversal of the metabolic acidosis. The main goals of therapy--including correction of dehydration, electrolyte abnormalities and acidosis via aggressive fluid therapy with electrolyte supplementation and correction of ketoacidosis and hyperglycemia via initiation of insulin therapy--can be achieved if these steps are followed. Because of the severity of metabolic alterations in the DKA animal, frequent and careful monitoring are paramount because they will allow the clinician to tailor treatment to each case.