Distribution, prevalence, and genetic characterization of Baylisascaris procyonis in selected areas of Georgia

Baylisascaris procyonis is an intestinal nematode of raccoons (Procyon lotor) that can cause fatal larval migrans in numerous species of birds and mammals, including humans. Although this parasite has historically been absent in the southeastern United States, it has been found in isolated regions in the Appalachian Mountains and was recently documented in DeKalb County, Georgia. The first objective of the current study was to investigate the distribution and prevalence of B. procyonis in selected populations of raccoons in Georgia. Intestinal tracts of 312 raccoons from 25 Georgia counties were examined for B. procyonis. The only county where B. procyonis was detected was Clarke County, where 12 of 116 (10.3%) raccoons were infected. In Clarke County, significantly more juveniles (P = 0.049) were infected compared with adults, and no differences in prevalence were noted by sex, season of capture, or land use (rural vs. urban); however, significantly (P = 0.0370) higher worm burdens were found in infected raccoons from urban/suburban locations compared with rural areas. In addition, Toxascaris leonina , a morphologically similar ascarid, was found in 3 raccoons from Clarke County (n = 2) and Morgan County (n = 1). A second objective was to determine if sequence polymorphisms were associated with B. procyonis from different geographic regions. Because sequences from a single worm from Japan had been entered into GenBank, we obtained nematodes from Kentucky and Texas for comparison with our samples from Georgia. Sequence analysis of the 18S and 5.8S rRNA genes and the internal transcribed spacer (ITS) -1 and ITS-2 regions confirmed Georgia samples were B. procyonis. Although several polymorphic bases were observed within both ITS regions, none was associated with a particular geographic location. These data indicate that the distribution of B. procyonis within Georgia is increasing and only limited genetic variation is present in the rRNA and ITS gene regions among B. procyonis from the southern United States and introduced populations in Japan.     

Molecular basis of ESD*5 and ESD*7 and haplotype analysis with new polymorphisms in introns

The two polymorphic alleles of esterase D (ESD), ESD*5 and ESD*7, are specific to Europeans and Asians, respectively. In this study the molecular basis was characterized: ESD*5, arising from ESD*1, has a G to A transition, resulting in Gly257(GGT) --> Asp(GAT); and ESD*7, originating from ESD*2, has an A to G transition, resulting in Asp231(GAT) --> Gly(GGT). Glycine is also involved in the common ESD*1/ESD*2 polymorphism [Gly190(GGA) --> Glu(GAA)]. Haplotype analysis using a few novel intragenic polymorphisms showed strong associations among polymorphic sites, suggesting that recombination has been less frequent in the human ESD gene, although it spans about 25 kb from exon 1 to exon 10. A marked difference was observed in the distribution of haplotype frequencies between Germans and Japanese.     

Three parallel quorum-sensing systems regulate gene expression in Vibrio harveyi

In a process called quorum sensing, bacteria communicate using extracellular signal molecules termed autoinducers. Two parallel quorum-sensing systems have been identified in the marine bacterium Vibrio harveyi. System 1 consists of the LuxM-dependent autoinducer HAI-1 and the HAI-1 sensor, LuxN. System 2 consists of the LuxS-dependent autoinducer AI-2 and the AI-2 detector, LuxPQ. The related bacterium, Vibrio cholerae, a human pathogen, possesses System 2 (LuxS, AI-2, and LuxPQ) but does not have obvious homologues of V. harveyi System 1. Rather, System 1 of V. cholerae is made up of the CqsA-dependent autoinducer CAI-1 and a sensor called CqsS. Using a V. cholerae CAI-1 reporter strain we show that many other marine bacteria, including V. harveyi, produce CAI-1 activity. Genetic analysis of V. harveyi reveals cqsA and cqsS, and phenotypic analysis of V. harveyi cqsA and cqsS mutants shows that these functions comprise a third V. harveyi quorum-sensing system that acts in parallel to Systems 1 and 2. Together these communication systems act as a three-way coincidence detector in the regulation of a variety of genes, including those responsible for bioluminescence, type III secretion, and metalloprotease production.     

Effect of short-term coyote removal on populations of coyote helminths

Coyote (Canis latrans) removal programs often are initiated despite the potential population regulatory mechanism of parasitism with increased coyote density. We investigated the effect of intensive, short-term coyote removal on population levels of helminths in juvenile and adult coyotes from western Texas. Coyotes were killed by aerial gunning every 3 mo for 2 yr on two 5,000 ha areas, which reduced the overall coyote density of these areas by about 50%. Two other 5,000 ha areas were used as comparison sites where a limited number of coyotes were killed each season. Densities on comparison sites remained stable throughout the study at a mean +/- 1 SE of 0.14 +/- 0.01 coyotes/km2. Twelve helminth species consisting of seven nematodes (Ancylostoma caninum, Physaloptera rara, Toxascaris leonina, Dirofilaria immitis, Spirocerca lupi, Oslerus osleri, and Capillaria aerophila), three cestodes (Taenia pisiformis, Taenia multiceps, and Mesocestoides sp.), one acanthocephalan (Oncicola canis), and one trematode (Alaria marcianae) were found in 252 coyotes. Of these, A. caninum, P. rara, T. multiceps, T. pisiformis, T. leonina, and S. lupi were common species. Rank-transformed values for the mean abundances of A. caninum and T. multiceps and A. caninum, T. multiceps, and S. lupi were reduced in juvenile and adult coyotes, respectively, from the removal sites compared to respective helminth abundances in similar age class coyotes from comparison sites. Because A. caninum has been suggested as a population regulator of coyotes, a coyote removal program that results in a reduced density of coyotes and at the same time causes a reduced abundance of A. caninum, may in fact negate the regulatory effect that A. caninum has on coyote populations.     

Direct enantiospecific HPLC bioanalysis of (R,S)-atenolol on a chiral stationary phase

The simultaneous determination of the enantiomers of the β₁-selective adrenergic antagonist atenolol in human plasma and urine is described. After an alkaline preextraction atenolol is extracted from biological material at pH 12.3 using dichloromethane/propan-2-ol. The separation of the underivatized enantiomers is achieved by high-performance liquid chromatography on a chiral stationary phase (Chiralcel OD, cellulose tris-3, 5-dimethylphenylcarbamate, coated on silica gel) with fluorimetric detection. (?)-(S)-Pindolol is used as an internal standard. The detection limits of 5 ng/ml enantiomer in plasma and 50 ng/ml enantiomer in urine are sufficient for pharmacokinetic studies after therapeutic doses. © 1993 Wiley-Liss, Inc.     

beta-Aspartokinase from developing endosperm of maize.

β-aspartokinase (EC 2.7.2.4.) has been isolated from the developing endosperm (30 days post-pollination) of Zea mays (cv. Pioneer 3145). Enzyme activity was dependent upon ATP, Mg⁺⁺ or Mn⁺⁺, aspartate, and protein concentration. Double reciprocal plots of velocity vs. aspartate concentrations deviated from a straight line at low aspartate concentration indicating two apparent Km's of 0.5 and 6.6 mM. Enzyme activity was inhibited by lysine but not by methionine or threonine. The endosperm-derived β-aspartokinase behaved similarly to enzyme isolated from 6-day-old etiolated shoot tissue. The presence of β-aspartokinase in developing endosperm provides new insight into the source of the aspartate-derived amino acids in maize endosperm.     

Bedding disposal cabinet for containment of aerosols generated by animal cage cleaning procedures.

Laboratory tests with aerosolized spores and animal room tests with uranine dye indicate the effectiveness of a prototype bedding disposal cabinet in reducing airborne contamination generated by cage cleaning procedures.     

Arrangement and localization of the human GM-CSF receptor alpha chain gene CSF2RA within the X-Y pseudoautosomal region.

The gene encoding one subunit of the receptor for the hemopoietic growth factor, GM-CSF, has been previously localized to the short arm of the human sex chromosomes. By pulsed-field gel electrophoresis, the precise localization of this gene, CSF2RA, within the pseudoautosomal region has been determined. The gene is located 1180 to 1300 kb from the telomere, in close proximity to the CpG island B5. The CSF2RA gene spans at least 45 kb, and a representation of most of the gene on three overlapping cosmid clones has been obtained. The exon(s) encoding the first 35 bp of cDNA sequence lies outside these cosmids. The CSF2RA gene is characterized by abundant hypervariable sequences, and a number of informative restriction fragment length polymorphisms have been defined.     

The Topographical Distribution of Alanine, Aspartate, γ-Aminobutyric Acid, Glutamate, Glutamine, and Glycine in the Pigeon Optic Tectum and the Effect of Retinal Ablation

Abstract: The concentrations of alanine, aspartate, γ-aminobutyric acid, glutamine, glutamate, and glycine were measured in the pigeon optic nerve and in the individual tectal layers. Characteristic topographical distribution patterns were observed for the different amino acids. After unilateral retinal ablation, the concentration of aspartate and glutamate was decreased in the nerve and contralateral tectum. The reduction was restricted to the superficial part of the tectum, which receives a direct retinal input. The maximal loss was measured in the first two layers, where aspartate was reduced by 51% and glutamate by 75% in comparison with the ipsilateral side 4 weeks after ablation. The results favor a special role for aspartate and glutamate in pigeon retino-tectal afferents.