Diagnosis of canine echinococcosis: comparison of coproantigen detection with necropsy in stray dogs and red foxes from northern Jordan

The sandwich enzyme linked immunosorbent assay (ELISA) was used as a diagnostic test for Echinococcus granulosus infection by detecting coproantigens in 94 stray dogs Canis familiaris and eight red foxes (Vulpes vulpes) from northern Jordan. The results were analyzed in relation to actual helminth infection as revealed by necropsy. The infection rate of dogs with E. granulosus was 13.8% with a worm load ranging between 3-> 10,000 per infected dog. In contrast, eight of 13 E. granulosus infected dogs were coproantigen positive (overall sensitivity 61.5%). The sensitivity increased to 87.5% and 100% in dogs harboring > 20 and > 100 worms/dog, respectively. The specificity of coproantigen-ELISA was 91%. The greatest cross-reactivity was found in dogs infected with Dipylidium caninum. The positive and negative predictive values for the coproantigen-ELISA test were 50% and 94.2%, respectively. Thus, a coproantigen negative dog is most probably truly negative for E. granulosus. In contrast, a coproantigen positive dog may not be truly positive for E. granulosus, except if it has a high worm burden of > 100 worms/animal.     

Failure to identify alveolar echinococcosis in trappers from South Dakota in spite of high prevalence of Echinococcus multilocularis in wild canids

Echinococcus multilocularis causes a rare but potentially lethal zoonotic disease in humans. This tapeworm has been known to be endemic in foxes (Vulpes vulpes) and coyotes (Canis latrans) within the northern United States since the 1960s. One purpose of this study was to provide recent data on the prevalence of E. multilocularis in foxes and coyotes from eastern South Dakota. In a survey conducted from 1987 to 1991 and involving 137 foxes and 9 coyotes from this area, 74.5% of the foxes and 4 of the coyotes were infected. To assess the possible prevalence of alveolar echinococcosis in a group at presumptive high risk, we also conducted a serological survey of members of the South Dakota Trappers Association in 1990 and 1991. Serum samples from 115 trappers were evaluated for the presence of E. multilocularis antibodies using enzyme-linked immunosorbent assay tests involving a purified antigen called Em2, a crude E. multilocularis antigen, and a recombinant E. multilocularis antigen called II/3-10. None of the trappers showed antibody evidence for the presence of E. multilocularis. Roughly half of the surveyed individuals had trapped more than 50 foxes during their life, and almost one-fourth had trapped more than 1,000 foxes.     

Exploring the effect of xenon on biomembranes

We report the initial findings of 100 ns molecular dynamics simulations of the role of cellular membranes in general anaesthesia. The effect of xenon on hydrated dipalmitoylphosphatidylcholine bilayers is described. The xenon atoms were found to prefer the interfacial and central regions of the bilayer. The presence of xenon was observed to lead to a small increase in the surface area, membrane thickness, and order of the acyl chains.     

Nitrogen efflux from the sediments of a subtropical bay and the potential contribution to macroalgal nutrient requirements

The concentration of dissolved inorganic nitrogen (DIN) in the porewaters of shallow-water tropical marine sediments can be as high as 50-100 μM, at sediment depths of shallow as 20 cm. These concentrations are at least two-orders of magnitude greater than the DIN concentration in the overlying water. High porewater concentrations, and the resulting concentration gradient, result in substantial efflux of DIN from the sediments to the water column. This sediment-derived DIN may be an important nutrient source for benthic algae. In Kaneohe Bay, Hawaii, a mean ammonium efflux rate of 490 μmolm(-2)day(-1) and a mean nitrate+nitrite efflux rate of 123 μmolm(-2)day(-1) were measured on reef slopes in the habitat occupied by benthic algae. It has been demonstrated that this nutrient source is essential for the growth of at least one abundant alga, Dictyosphaeria cavernosa, and possibly others. The DIN concentrations in Kaneohe Bay sediment porewaters, and the rates of DIN efflux from those sediments, are greater than porewater concentrations and efflux rates reported for other, more pristine tropical sites. The rate of sedimentation of particulate nitrogen is similar to rates reported from other tropical lagoons, and about twice as high as the efflux rate of total dissolved nitrogen. Given the present low nutrient concentrations in the water column of the Bay, these results support the view that nutrient efflux from the benthos is in part responsible for the persistence of D. cavernosa on these reefs. It is possible that efflux of DIN from sediments may be responsible for sustained benthic algal productivity in similar habitats on other tropical reefs.     

Identification of a cDNA for the plastid-located geranylgeranyl pyrophosphate synthase from Capsicum annuum: correlative increase in enzyme activity and transcript level during fruit ripening

Geranylgeranyl pyrophosphate synthase is a key enzyme in plant terpenoid biosynthesis. Using specific antibodies, a cDNA encoding geranylgeranyl pyrophosphate synthase has been isolated from bell pepper (Capsicum annuum) ripening fruit. The cloned cDNA codes for a high molecular weight precursor of 369 amino acids which contains a transit peptide of approximately 60 amino acids. In-situ immunolocalization experiments have demonstrated that geranylgeranyl pyrophosphate synthase is located exclusively in the plastids. Expression of the cloned cDNA in E. coli has unambiguously demonstrated that the encoded polypeptide catalyzes the synthesis of geranylgeranyl pyrophosphate by the addition of isopentenyl pyrophosphate to an allylic pyrophosphate. Peptide sequence comparisons revealed significant similarity between the sequences of the C. annuum geranylgeranyl pyrophosphate synthase and those deduced from carotenoid biosynthesis (crtE) genes from photosynthetic and non-photosynthetic bacteria. In addition, four highly conserved regions, which are found in various prenyltransferases, were identified. Furthermore, evidence is provided suggesting that conserved and exposed carboxylates are directly involved in the catalytic mechanism. Finally, the expression of the geranylgeranyl pyrophosphate synthase gene is demonstrated to be strongly induced during the chloroplast to chromoplast transition which occurs in ripening fruits, and is correlated with an increase in enzyme activity.     

A revision of the Puerto Rican species of lepanthes (Orchidaceae)

Six species of the orchid speciesLepanthes are described as new. A seventh species,L. sanguined, previously known only from Jamaica, is reported from Puerto Rico. The current misspelling ofL. selenitepala, the only species of the genus previously reported from Puerto Rico, is corrected. A key to the eight Puerto Rican species ofLepanthes is presented, and the value of several interesting taxonomic characters is discussed. The possibility of apogamy in this genus is raised, and detailed biosystematic investigations are indicated as necessary for a complete understanding of the group.     

Meningococcal pilin: a glycoprotein substituted with digalactosyl 2,4-diacetamido-2,4,6-trideoxyhexose

Neisseria meningitidis pili are filamentous protein structures that are essential adhesins in capsulate bacteria. Pili of adhesion variants of meningococcal strain C311 contain glycosyl residues on pilin (PilE), their major structural subunit. Despite the presence of three potential N -linked glycosylation sites, none appears to be occupied in these pilins. Instead, a novel O -linked trisaccharide substituent, not previously found as a constituent of glycoproteins, is present within a peptide spanning amino acid residues 45 to 73 of the PilE molecule. This structure contains a terminal 1-4-linked digalactose moiety covalently linked to a 2,4-diacetamido-2,4,6-trideoxyhexose sugar which is directly attached to pilin. Pilins derived from galactose epimerase ( galE ) mutants lack the digalactosyl moiety, but retain the diacetamidotrideoxyhexose substitution. Both parental (#3) pilins and those derived from a hyper-adherent variant (#16) contained identical sugar substitutions in this region of pilin, and galE mutants of #3 were similar to the parental phenotype in their adherence to host cells. These studies have confirmed our previous observations that meningococcal pili are glycosylated and provided the first structural evidence for the presence of covalently linked carbohydrate on pili. In addition, they have revealed a completely novel protein/saccharide linkage.     

Echinococcus shiquicus n. sp., a taeniid cestode from Tibetan fox and plateau pika in China

The taeniid cestode Echinococcus shiquicus n. sp. was found from the Tibetan fox Vulpes ferrilata and the plateau pika Ochotona curzoniae in the Qinghai-Tibet plateau region of China. In the adult stage, E. shiquicus from the foxes is morphologically similar to Echinococcus multilocularis. However, the new species is differentiated by its smaller rostellar hooks, fewer segments, distinct position of genital pore in the mature segment and fewer eggs in the gravid segment. Hydatid cysts of E. shiquicus found in the livers from the pikas were essentially unilocular but an oligovesicular cyst was also found. The data of mitochondrial and nuclear DNA sequences proved E. shiquicus to be a valid taxon.     

Economic impact of cystic echinococcosis in peru

Background

Cystic echinococcosis (CE) constitutes an important public health problem in Peru. However, no studies have attempted to estimate the monetary and non-monetary impact of CE in Peruvian society.

Methods

We used official and published sources of epidemiological and economic information to estimate direct and indirect costs associated with livestock production losses and human disease in addition to surgical CE-associated disability adjusted life years (DALYs) lost.

Findings

The total estimated cost of human CE in Peru was U.S.$2,420,348 (95% CI:1,118,384–4,812,722) per year. Total estimated livestock-associated costs due to CE ranged from U.S.$196,681 (95% CI:141,641–251,629) if only direct losses (i.e., cattle and sheep liver destruction) were taken into consideration to U.S.$3,846,754 (95% CI:2,676,181–4,911,383) if additional production losses (liver condemnation, decreased carcass weight, wool losses, decreased milk production) were accounted for. An estimated 1,139 (95% CI: 861–1,489) DALYs were also lost due to surgical cases of CE.

Conclusions

This preliminary and conservative assessment of the socio-economic impact of CE on Peru, which is based largely on official sources of information, very likely underestimates the true extent of the problem. Nevertheless, these estimates illustrate the negative economic impact of CE in Peru.     

Monoclonal antibody technology for mycotoxins

Specific monoclonal antibodies (MABs) against aflatoxins, ochratoxin A, zearalenone, diacetoxyscirpenol and T-2 toxin have been prepared in various laboratories by the application of hybridoma technology to mycotoxins. These antibodies can be selected for sensitivity, reduced cross-reactivity, reliability and ease of production. When a suitable antibody is chosen it can then be used in a rapid immunological method such as an enzyme-linked or radio-immunoassay or immunoaffinity chromatography system. These assays have a lower limit of mycotoxin detection in the ng/ml range and have been applied to the determination of mycotoxins in samples such as maize, peanuts, peanut butter, milk and porcine kidneys. Using these immunoassay techniques, sample preparation has generally been simplified to a matter of solvent extraction of mycotoxins from the sample followed by dilution; under these conditions, levels of 1-5ug of mycotoxins/kg of sample can be found. The application and advantages of MABs to mycotoxins and the use of these antibodies in various assay techniques is discussed.