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.     

不同季节和冬眠时相中达乌尔黄鼠视前区温敏神经元特性和下丘脑内NA代谢的变化

比较了不同季节和冬眠时相中达乌尔黄鼠 (Citelleusdauricus)下丘脑内去甲肾上腺素 (noradrenaline ,NA)代谢和视前区 (POA)脑片中各类温敏神经元的比例、温度敏感性、放电活动的临界温度及下限温度 .结果表明 :与夏季动物相比 ,( 1)冬眠各时相中POA温敏神经元的比例和温敏性产生了与冬眠体温调节特性相关的适应性改变 ;( 2 )冬季和冬眠中POA神经元放电的下限温度和温敏神经元活动的临界温度均显著下移 ;( 3 )冬眠中POA神经元对NA反应的敏感性增高 ,冷敏神经元对NA的反应从夏季的抑制型转变为冬眠时的兴奋型 ;( 4)入眠和深冬眠时下丘脑内NA的含量和代谢水平下降 ,出眠时代谢水平升高 .这些变化可能解释动物入眠时主动降低体温和出眠时从深低体温中快速地升温的温度调节机理 .     

Substitution bias, rapid saturation, and the use of mtDNA for nematode systematics

Only relatively recently have researchers turned to molecular methods for nematode phylogeny reconstruction. Thus, we lack the extensive literature on evolutionary patterns and phylogenetic usefulness of different DNA regions for nematodes that exists for other taxa. Here, we examine the usefulness of mtDNA for nematode phylogeny reconstruction and provide data that can be used for a priori character weighting or for parameter specification in models of sequence evolution. We estimated the substitution pattern for the mitochondrial ND4 gene from intraspecific comparisons in four species of parasitic nematodes from the family Trichostrongylidae (38-50 sequences per species). The resulting pattern suggests a strong mutational bias toward A and T, and a lower transition/transversion ratio than is typically observed in other taxa. We also present information on the relative rates of substitution at first, second, and third codon positions and on relative rates of saturation of different types of substitutions in comparisons ranging from intraspecific to interordinal. Silent sites saturate extremely quickly, presumably owing to the substitution bias and, perhaps, to an accelerated mutation rate. Results emphasize the importance of using only the most closely related sequences in order to infer patterns of substitution accurately for nematodes or for other taxa having strongly composition-biased DNA. ND4 also shows high amino acid polymorphism at both the intra- and interspecific levels, and in higher level comparisons, there is evidence of saturation at variable amino acid sites. In general, we recommend using mtDNA coding genes only for phylogenetics of relatively closely related nematode species and, even then, using only nonsynonymous substitutions and the more conserved mitochondrial genes (e.g., cytochrome oxidases). On the other hand, the high substitution rate in genes such as ND4 should make them excellent for population genetics studies, identifying cryptic species, and resolving relationships among closely related congeners when other markers show insufficient variation.      

Identification of an alpha3-fucosyltransferase and a novel alpha2- fucosyltransferase activity in cercariae of the schistosome Trichobilharzia ocellata: biosynthesis of the Fucalpha1-->2Fucalpha1-- >3[Gal(NAc)beta1-->4]GlcNAc sequence

Fucose is a major constituent of the protein- and lipid-linked glycans of the various life-cycle stages of schistosomes. These fucosylated glycans are highly antigenic and seem to play a role in the pathology of schistosomiasis. In this article we describe the identification and characterization of two fucosyltransferases (FucTs) in cercariae of the avian schistosome Trichobilharzia ocellata, a GDP-Fuc:[Galbeta1-- >4]GlcNAcbeta-R alpha1-->3-FucT and a novel GDP-Fuc:Fucalpha-R alpha1-- >2-FucT. Triton X-100 extracts of cercariae were assayed for FucT activity using a variety of acceptor substrates. Type 1 chain (Galbeta1- ->3GlcNAc) based compounds were poor acceptors, whereas those based on a type 2 chain (Galbeta1-->4GlcNAc), whether alpha2'-fucosylated, alpha3'-sialylated, or unsubstituted, and whether present as oligosaccharide or contained in a glycopeptide or glycoprotein, all served as acceptor substrates. In this respect the schistosomal alpha3- FucT resembles human FucT V and VI rather than other known FucTs. N- ethylmaleimide, an inhibitor of several human FucTs, had no effect on the activity of the schistosomal alpha3-FucT, whereas GDP-beta-S was strongly inhibitory. Large scale incubations were carried out with Galbeta1-->4GlcNAc, GalNAcbeta1-->4GlcNAcbeta-O -(CH2)8COOCH3 and Fucalpha1-->3GlcNAcbeta1-->2Man as acceptor substrates and the products of the incubations were isolated using a sequence of chromatographic techniques. By methylation analysis and 2D-TOCSY and ROESY1H-NMR spectroscopy the products formed were shown to be Galbeta1-- >4[Fucalpha1-->2Fucalpha1-->3]GlcNAc, GalNAcbeta1-->4[Fucalpha1-- >2Fucalpha1-->3]GlcNAcbe ta-O-(CH2)8COOCH3, and Fucalpha1-->2Fucalpha1-- >3GlcNAcbeta1-->2Man, respectively. It is concluded that the alpha2- FucT and alpha3-FucT are involved in the biosynthesis of the (oligomeric) Lewisx sequences and the Fucalpha1-->2Fucalpha1-->3GlcNAc structural element that have been described on schistosomal glycoconjugates.      

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.