Proposed field evaluation of a rabies recombinant vaccine for raccoons (Procyon lotor): site selection, target species characteristics, and placebo baiting trials

Prior to a limited field application of an orally-administered vaccinia-rabies glycoprotein (V-RG) recombinant virus vaccine for wildlife, background data were obtained for the proposed site on Parramore Island, Virginia (USA). Mammalian target and nontarget species, potentially at risk for exposure to vaccine were inventoried. Placebo baiting trials with a fishmeal polymer bait resulted in high bait disturbance (88 to 100%), primarily by raccoons (Procyon lotor), with infrequent visitation and no evidence of bait consumption by deer (Odocoileus virginianus), small mammals or avian species. Definitive bait acceptance rates by raccoons (indicative of bait ingestion) were difficult to accurately determine based exclusively on premolar and vibrissae samples collected antemortem from live-trapped raccoons for tetracycline and rhodamine B biomarker analyses, respectively. Bait acceptance rate was more accurately determined during a pilot baiting trial conducted on North Island, South Carolina, when mandibles (postmortem samples) were examined for tetracycline incorporation. Parasitologic findings in raccoons on Parramore Island included Hepatozoan procyonis, Phagicola angrense and Physaloptera rara and a variety of incidental microscopic lesions, and provided baseline pathological data for comparison subsequent to V-RG vaccine application. A population density estimate of one raccoon/2.7 ha was calculated using mark-recapture data for comparison after vaccine deployment. Limited reproductive data, including estimates of pregnancy rates by palpation, the number of live kits/litter live-trapped with previously pregnant raccoons or observed in the dens of radio-collared raccoons, was gathered to assess the effect of proposed oral vaccination with V-RG vaccine. Home ranges were assessed by radio-telemetry of 15 raccoons; all radio-collared raccoons currently reside on Parramore Island.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of attractants and repellents on methyl group turnover on methyl-accepting chemotaxis proteins of Bacillus subtilis and role of CheW.

The ability of attractants and repellents to affect the turnover of methyl groups on the methyl-accepting chemotaxis proteins (MCPs) was examined for Bacillus subtilis. Attractants were found to cause an increase in the turnover of methyl groups esterified to the MCPs, while repellents caused a decrease. These reactions do not require CheW. However, a cheW null mutant exhibits enhanced turnover in unstimulated cells. Assuming that the turnover of methyl groups on the MCPs reflects a change in the activity of CheA, these results suggest that the activation of CheA via chemoeffector binding at the receptor does not require CheW.     

Structural transitions of deoxyribonucleic acid in aqueous electrolyte solutions. I. Reference spectra of conformational limits.

The circular dichroism properties of calf thymus DNA have been examined at 27 degrees over the wavelength range of 215-300 nm in aqueous solutions of NaCl, KCl, LiCl, CsCl, and NH4Cl at pH 7. The concentrations of these electrolytes were varied from 0.01 to ca. 5-10 m. The spectral changes induced by changes in concentration of NaCl and KCl and all but the highest concentrations of NH4Cl as well as lower concentrations of Cstcl and LiCl could be represented by a common two-state transition involving the conversion of the typical conservative spectrum commonly seen in dilute solutions of these salts to a nonconservative spectrum similar to that obtained by Tunis-Schneider and Maestre ((1970), J. Mol. Biol. 52, 521) for the C form of DNA. At higher concentrations of CsCl, LiCl, and NH4Cl, an additional component, resembling an A type spectrum, was required to account for the observed CD changes with changing concentration of electrolyte. Relying on the published spectra of the B, the C, and the A forms of DNA by Tunis-Schneider and Maestre for identification and approximate values of the molecular ellipticities of these forms, we have analyzed these spectral transitions by two least mean squares methods in order to obtain accurate reference spectra of aqueous "B", C, and "A" conformations of calf thymus DNA. The results obtained suggest that although the C form in solution is identical with that obtained in film, the aqueous B conformational limit is not identical with the crystallographic Watson-Crick structure. In addition, the A form generated in solution under our experimental conditions appears to be more similar to that assumed by low molecular weight Escherichia coli DNA at 75% relative humidity rather than calf thymus DNA at the same relative humidity.     

Structural transitions of calf thymus DNA in concentrated LiCl solutions

The solubility, sedimentation, circular dichroism, and absorption spectral characteristics of calf thymus DNA have been examined in concentrated solutions of LiCl (6-13 m) at 25 to 27 degree C. At all concentrations of LiCl, the DNA is base stacked and exhibits normal hypochromicty, At the upper end of this range of LiCl concentrations, DNA aggregates and ultimately precipitates completely from solution between 13 and 14 m LiCl. This aggregation process is dependent on concentration, base composition, and molecular weight of DNA. The sedimentation velocity data taken together with the absorbance spectral data suggest that the aggregation process leading to the formaiton of large structures beings at approximately equal to 9 m. Prior to the onset of aggregation, the circular dichroism (CD) spectra can be adequately fitted by a linear combination of contributions of the B, C, and A forms of DNA (Hanlon, S., Brudno, S., Wu, T. T., and Wolf, B. (1975), Biochemistry 14, 1648). Above 9 m LiCl, both factor analysis and a primitive version of matrix rank order analysis indicate that at least one additional spectral component is required to account for the observed CD spectra above 260 nm. The general shape of this additional component or distortion resembles the psi form of DNA.     

The Effect of Mixing Entire Male Pigs Prior to Transport to Slaughter on Behaviour,Welfare and Carcass Lesions

Research is needed to validate lesions recorded at meat inspection as indicators of pig welfare on farm. The aims were to determine the influence of mixing pigs on carcass lesions and to establish whether such lesions correlate with pig behaviour and lesions scored on farm. Aggressive and mounting behaviour of pigs in three single sex pens was recorded on Day −5, −2, and −1 relative to slaughter (Day 0). On Day 0 pigs were randomly allocated to 3 treatments (n = 20/group) over 5 replicates: males mixed with females (MF), males mixed with males (MM), and males unmixed (MUM). Aggressive and mounting behaviours were recorded on Day 0 at holding on farm and lairage. Skin/tail lesions were scored according to severity at the farm (Day −1), lairage, and on the carcass (Day 0). Effect of treatment and time on behaviour and lesions were analysed by mixed models. Spearman rank correlations between behaviour and lesion scores and between scores recorded at different stages were determined. In general, MM performed more aggressive behaviour (50.4 ± 10.72) than MUM (20.3 ± 9.55, P < 0.05) and more mounting (30.9 ± 9.99) than MF (11.4 ± 3.76) and MUM (9.8 ± 3.74, P < 0.05). Skin lesion scores increased between farm (Day −1) and lairage (P < 0.001), but this tended to be significant only for MF and MM (P = 0.08). There was no effect of treatment on carcass lesions and no associations were found with fighting/mounting. Mixing entire males prior to slaughter stimulated mounting and aggressive behaviour but did not influence carcass lesion scores. Carcass skin/tail lesions scores were correlated with scores recorded on farm (r_skin = 0.21 and r_tail = 0.18, P < 0.01) suggesting that information recorded at meat inspection could be used as indicators of pig welfare on farm.     

Variation in genomic alu repeat density as a basis for rapid construction of low resolution physical maps of human chromosomes

Human DNA restriction fragments containing high numbers of Alu repeat sequences can be preferentially detected in the presence of other human DNA restriction fragments in DNA from human:rodent somatic cell hybrids when the DNA is fragmented with enzymes that cleave mammalian DNA infrequently. This ability to lower the observed human DNA complexity allowed us to develop an approach to order rapidly somatic hybrid cell lines retaining overlapping human genomic domains. The ordering process also generates a relative physical map of the human fragments detected with Alu probe DNA. This process can generate physical mapping information for human genomic domains as large as an entire chromosome (100,000 kb). The strategy is demonstrated by ordering Alu-detected NotI fragments in a panel of mouse:human hybrid cells that span the entire long arm of human chromosome 17.by L. Manuelidis