Seroprevalence of <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> sensu lato and <Emphasis Type="Italic">Anaplasma phagocytophilum</Emphasis> in Danish horses

Background

Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum are able to infect horses. However, the extend to which Danish horses are infected and seroconvert due to these two bacteria is unknown. The aim of the present study was to evaluate the seroprevalence of B. burgdorferi sensu lato and A. phagocytophilum in Danish horses.

Methods

A total of 390 blood samples collected from all major regions of Denmark and with a geographical distribution corresponding to the density of the Danish horse population were analyzed. All samples were examined for the presence of antibodies against B. burgdorferi sensu lato and A. phagocytophilum by the use of the SNAP^®4DX ^® ELISA test.

Results

Overall, 29.0% of the horses were seropositive for B. burgdorferi sensu lato whereas 22.3% were seropositive for A. phagocytophilum.

Conclusions

Antibodies against B burgdorferi sensu lato and A. phagocytophilum are commonly found among Danish horses thus showing that Danish horses are frequently infected by these organisms.

     

Estimates of DNA and protein sequence divergence: an examination of some assumptions

Some of the assumptions underlying estimates of DNA and protein sequence divergence are examined. A solution for the variance of these estimates that allows for different mutation rates and different population sizes in each species and for an arbitrary structure in the initial population is obtained. It is shown that these conditions do not strongly affect estimates of divergence. In general, they cause the variance of divergence to be smaller than a binomial variance. Thus, the binomial variance that is usually assumed for these estimates is safely conservative. It is shown that variability in the mutation rate among sites can have an effect as large as or larger than variability in the mutation rate among bases. Variability in the mutation rate among bases and among sites causes the number of substitutions between two sequences to be underestimated. Protein and DNA sequences from several species are collected to estimate the variability in mutation rates among sites. When many homologous sequences are known, standard methods to estimate this variability can be used. The estimates of this variability show that this factor is important when considering the spectrum of spontaneous mutations and is strongly reflected in the divergence of sequences. Smaller variability is found for the third position of codons than for the first and second codon positions. This may be because of less selective constraints on this position or because the third position has been saturated with mutations for the sequences examined.      

Steroids in Porifera. II. Steroid derivatives from two sponges of the family Halichondriidae. Sokotrasterol sulfate, a marine steroid with a new pattern of side chain alkylation

A trisulfated derivative of 24,25,26,26-tetramethyl-5 alpha-cholest-23E-ene-2 alpha, 3 beta, 6 alpha-triol (sokotrasterol sulfate) has been isolated from the sponge Halichondriidae gen. sp., collected near Sokotra Island (Arabian Sea), and its structure has been elucidated. The side chain of the new steroid involves a "normal" alkylation at C-24 and the unprecedented addition of two extra methyl groups at C-26 and one extra methyl group at C-25. A free sterol fraction contained only 24-isopropyl-5-cholesten-3 beta-ol and 24-isopropyl-5, 22E-cholestadien-3 beta-ol. 24-Isopropyl-5, 22E-cholestadien-3 beta-ol as sole monohydroxy sterol and halistanol sulfate as major polyhydroxylated steroid derivative have been detected in Halichondria sp., a Madagascar sponge.     

Cauloside D a new triterpenoid glycoside from Caulophyllum robustum maxim: Identification of cauloside A

The structure of cauloside D, one of the main saponins isolated from Caulophyllum robustum roots, was shown to be 3-O-α-l-arabinopyranosyl hederagenin-28-O-α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl(1→6)-β-d-glucopyranoside with the aid of methylation and enzymatic hydrolysis by the digestive juice of the Eulota maackii. Cauloside A was shown to be identical with saponin A, isolated from C. robustum Maxim. previously. The composition of the digestive juice of E. maakii was shown to include enzymes that catalyse the cleavage of α-arabinosidic, β-1,6-glucosidic and acyl-O-β-glucosidic linkages.     

Action of neurotoxin from the sea anemoneHomostichanthus duerdemi on inward sodium current in mammalian neurons

The action of purified toxin from the sea anemoneHomostichanthus duerdemi (HTX-1) on the inward sodium current was studied in experiments on isolated neurons from rat spinal ganglia and neuroblastoma cells of clone N-18F1, by an intracellular perfusion and voltage clamp method. HTX-1 was found to delay inactivation of the tetrodotoxin-(TTX-)sensitive inward sodium current and to make it incomplete, but virtually without affecting its activation. The relationship between the fraction of sodium channels modified by the toxin and the HTX-1 concentration is described by a Langmuir isotherm with association constant of (1.1 ± 0.1)·10^–7 M (holding potential –100 mV). Under the influence of the toxin the peak inward sodium current was increased by about 80%. Binding of HTX-1 with TTX-sensitive sodium channels is distinguished by strong potential-dependence: at a holding membrane potential of 0 mV the binding constant was an order of magnitude less than at a potential of –100 mV. In the case of brief action of HTX-1 on the nerve cell membrane (under 5 min) the effect of the toxin was completely reversible, but if the time of action of HTX-1 exceeded 30 min, subsequent washing with normal solution for 90 min did not abolish the effect completely.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Pacific Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 14, No. 4, pp. 402–409, July–August, 1982.     

Molecular phylogeny of diplomonads and enteromonads based on SSU rRNA,alpha-tubulin and HSP90 genes: Implications for the evolutionary history of the double karyomastigont of diplomonads

Background  

Fornicata is a relatively recently established group of protists that includes the diplokaryotic diplomonads (which have two similar nuclei per cell), and the monokaryotic enteromonads, retortamonads and Carpediemonas, with the more typical one nucleus per cell. The monophyly of the group was confirmed by molecular phylogenetic studies, but neither the internal phylogeny nor its position on the eukaryotic tree has been clearly resolved.     

Statins but not fibrates improve the atherogenic to anti-atherogenic lipoprotein particle ratio: a randomized crossover study

Background  

Prior studies suggested low density lipoprotein particle (LDLP) size is a predictor of atherosclerosis. Knowledge of effects of lipid lowering drugs on lipoprotein subclasses is useful. We treated subjects with hyperlipidemia sequentially with statins and fibrates, the 2 main classes of lipid lowering therapy and studied changes in NMR lipoprotein subclasses.