Serological evidence of an antibody response in farmed southern bluefin tuna naturally infected with the blood fluke Cardicola forsteri

In this study, adaptive immune response was investigated in farmed southern bluefin tuna, Thunnus maccoyii, infected with a sanguinicolid Cardicola forsteri. A cohort (Cohort₂₀₀₅) of southern bluefin tuna was sampled between March 2005 and August 2006. Samples were taken at the transfer of wild caught tuna to sea cages and then at regular intervals. Parasite intensity, abundance and prevalence data were recorded. An ELISA was developed to detect and quantify an antibody response against the blood fluke in southern bluefin tuna serum. Intensity and prevalence of the blood fluke were shown to peak in May 2005 at 10.9 flukes per infected fish (SE = 1.72) and 97.5% prevalence and then decreased to low prevalence (10%) and intensity (1.0). There were no significant changes in prevalence or intensity in 2006. Antibody titres and seroprevalence increased from 1.37 U μl⁻¹ and 10% at transfer in March 2005 to reach a peak in December 2005 of 25.86 U μl⁻¹ (SE = 6.26 U μl⁻¹) and 66.66%. No significant changes were observed in antibody titres for the same cohort of fish during 2006. Parasitological and serological values from Cohort₂₀₀₅ were compared to a 2006 cohort (Cohort₂₀₀₆) in March 2006 and August 2006 to determine if prior infection in Cohort₂₀₀₅ elicited any protection against infection in 2006. Although significant differences were not observed in intensities between cohorts it was shown that Cohort₂₀₀₅ had significantly lower abundances and prevalences of blood fluke infection than Cohort₂₀₀₆. Although there was no significant difference in mean antibody titres between cohorts in March 2006, the mean antibody titre of Cohort₂₀₀₆ was significantly greater than that of Cohort₂₀₀₅ in August 2006. No significant differences were observed in seroprevalence. This is one of the few studies to demonstrate the development of acquired resistance in fish against a parasite in an aquaculture environment under natural infection conditions.     

Purification and partial characterization of feline alpha1-proteinase inhibitor (falpha1-PI) and the development and validation of a radioimmunoassay for the measurement of falpha1-PI in serum

Alpha(1)-proteinase inhibitor (alpha(1)-PI) of the domestic cat (Felis catus) was purified from serum and a radioimmunoassay (RIA) for the measurement of feline alpha(1)-PI concentration in serum was developed and validated. Feline alpha(1)-PI (falpha(1)-PI) was isolated using ammonium sulfate precipitation, anion-exchange, size-exclusion, ceramic hydroxyapatite, and hydrophobic interaction chromatography. The molecular weight of falpha(1)-PI was estimated at 57,000 and the relative molecular mass (M(r)) was determined to be approximately 54.5 kDa. Isoelectric focusing revealed four bands with isoelectric points (pI) between 4.3 and 4.5. The N-terminal amino acid sequence of the first 19 residues was Glu-Gly-Leu-Gln-Gly-Ala-Ala-Val-Gln-Glu-Thr-Val-Ala-Ser-Gln-His-Asp-Gln-Glu. Antiserum against feline alpha(1)-PI was raised in rabbits. Tracer was produced by iodination ((125)I) of feline alpha(1)-PI using the chloramine T method. A radioimmunoassay was established and validated by determination of sensitivity, dilutional parallelism, spiking recovery, intra-assay variability, and inter-assay variability. A control range for serum feline alpha(1)-PI concentration was established from 50 healthy cats using the central 95th percentile. The sensitivity of the assay was 0.042 mg/ml. Observed to expected ratios for serial dilutions ranged from 105% to 141.18% for four different serum samples at dilutions of 1 in 35,000, 1 in 70,000, 1 in 140,000 and 1 in 280,000. Observed to expected ratios for spiking recovery ranged from 88.14% to 152.17% for four different serum samples and five different spiking concentrations. Coefficients of variation for four different serum samples were 4.57%, 6.45%, 8.52%, and 4.27% for intra-assay variability and 6.88%, 9.57%, 7.44%, and 9.94% for inter-assay variability. The reference range was established as 0.25-0.6 mg/ml. In summary, feline alpha(1)-PI was successfully purified from serum using a rapid and efficient method. The radioimmunoassay described here is sensitive, linear, accurate, precise, and reproducible and will facilitate further studies of the physiological or potential pathological role of alpha(1)-PI in cats.     

Squaramides as novel class I and IIB histone deacetylase inhibitors for topical treatment of cutaneous t-cell lymphoma

A series of squaramide-based hydroxamic acids were designed, synthesized and evaluated against human HDAC enzyme. Squaramides were found to be potent in the Hut78 cell line, but initially suffered from low solubility. Leads with improved solubility and metabolic profiles were shown to be class I, IIB and IV selective.     

A bioassay for insect deterrent compounds found in plant and animal tissues

A general field bioassay for detecting biologically active compounds in plants and insects has been developed and tested for efficacy and sensitivity. Methanolic extracts, in sucrose solution, of 20 plant and six caterpillar species were offered to the ponerine ant Paraponera clavata and the feeding preferences observed. The bioassay resulted in the detection of nine plant and three caterpillar species with ant-deterrent extracts, and 11 plant and three caterpillar species with neutral or attractant extracts. All of the plants showing ant-deterrent characteristics which had been chemically investigated in our laboratory, or for which chemical literature was available, contained secondary metabolites of known deterrence. Both naturally occurring and artificial differences in chemical concentrations could be detected using the bioassay. The method provides a means of screening plants and insects for compounds that are insect anti-feedants or that can modify insect behaviour.     

Development of an in vivo active,dual EP1 and EP3 selective antagonist based on a novel acyl sulfonamide bioisostere

Recent preclinical studies demonstrate a role for the prostaglandin E₂ (PGE₂) subtype 1 (EP1) receptor in mediating, at least in part, the pathophysiology of hypertension and diabetes mellitus. A series of amide and N-acylsulfonamide analogs of a previously described picolinic acid-based human EP1 receptor antagonist (7) were prepared. Each analog had improved selectivity at the mouse EP1 receptor over the mouse thromboxane receptor (TP). A subset of analogs gained affinity for the mouse PGE₂ subtype 3 (EP3) receptor, another potential therapeutic target. One analog (17) possessed equal selectivity for EP1 and EP3, displayed a sufficient in vivo residence time in mice, and lacked the potential for acyl glucuronide formation common to compound 7. Treatment of mice with 17 significantly attenuated the vasopressor activity resulting from an acute infusion of EP1 and EP3 receptor agonists. Compound 17 represents a potentially novel therapeutic in the treatment of hypertension and diabetes mellitus.