Blood lead levels of wild Steller's eiders (Polysticta stelleri) and black scoters (Melanitta nigra) in Alaska using a portable blood lead analyzer.

Sea duck populations are declining in Alaska. The reasons for the decline are not known; environmental lead exposure is one suspected cause. Thirty wild Steller's eider ducks (Polysticta stelleri) and 40 wild black scoter ducks (Melanitta nigra) were tested for blood lead levels using a portable blood lead analyzer (LeadCare; ESA, Inc., Chelmsford, Massachusetts 01824, USA). Sixty-seven and one-tenth percent of the sea ducks had undetectable blood lead levels, 30.0% had values indicating normal or background lead exposure, and 2.9% had values indicating lead exposure. None of the birds had values indicating lead toxicity, and no birds demonstrated clinical signs of toxicity. Birds in areas with higher human population density had higher blood lead levels than those in less densely populated areas. This is the first time a portable blood lead analyzer has been utilized with sea ducks in a field setting. Because it provides immediate results, it is valuable as a screening tool for investigators carrying out surgical procedures on birds in the field as well as establishing baseline blood lead data on sea ducks. Lead exposure does occur in wild sea ducks, and the study indicates that additional research is needed in order to determine the role environmental lead plays in declining sea duck populations.     

Influence of agricultural soils on the growth and reproduction of the bio-indicator Folsomia candida

Soil organisms have been recommended as bio-indicators of soil quality due to their sensitivity to anthropogenic influences and their high degree of site-specificity. The objectives of this study were to determine if the relationship between the soil Collembola, Folsomia candida, and forest soil could be extended to other soils and, if not, to determine the relationship between its life parameters and soils from the different phases of an agricultural rotation sequence. A comparison of growth, reproduction and survival of 1 day old neonates and 10 day old juveniles subjected to a series of different soils (composted manure, pasture soil, forest soil, sand alone, and sand supplemented with yeast) established that the association between F. candida and forest soil quality cannot be automatically transferred to soils from other ecosystems. The test also showed that neonate (1 d) individuals were more sensitive to the different soil treatments than 10 d old juveniles and should be used in future tests. On this basis, neonate F. candida individuals were used to determine if the species could be employed to characterize the agricultural soils from the different phases of an organic or conventional rotation sequence. Results demonstrated that changes in body growth and reproduction constituted suitable criteria to characterize the soil quality of these different phases. The research required to develop these results as a standard bio-indicator test of agricultural soil quality is discussed.     

Metastatic immune infiltrates correlate with those of the primary tumour in canine osteosarcoma

Our lack of understanding of the immune microenvironment in canine osteosarcoma (cOSA) has limited the identification of potential immunotherapeutic targets. In particular, our ability to utilize readily available tissue from a dog's primary tumour to predict the type and extent of immune response in their pulmonary metastatic lesions is unknown. We, therefore, collected 21 matched pairs of primary tumours and pulmonary metastatic lesions from dogs with OSA and performed immunohistochemistry to quantify T‐lymphocyte (CD3), FOXP3+ cell, B‐lymphocyte (Pax‐5), and CD204+ macrophage infiltration. We found that T‐lymphocytes and FOXP3+ infiltrates in primary tumours positively correlated with that of metastatic lesions (ρ = 0.512, P = 0.038 and ρ = 0.698, P = 0.007, respectively), while a strong trend existed for CD204+ infiltrates (ρ = 0.404, P = 0.087). We also observed T‐ and B‐lymphocytes, and CD204+ macrophages to be significantly higher in a dog's pulmonary metastasis compared to their primary tumour (P = 0.018, P = 0.018, P = 0.016, respectively), while FOXP3+ cells were only significantly higher in metastases when all primary tumour and metastasis lesions were compared without pairing (P = 0.036). Together, these findings suggest that the metastatic immune microenvironment may be influenced by that of the primary cOSA, and that primary tumour immune biomarkers could potentially be applied to predict immunotherapeutic responses in gross metastatic disease. We, therefore, provide a rationale for the treatment of cOSA pulmonary metastases with immunotherapeutics that enhance the anti‐tumour activity of these immune cells, particularly in dogs with moderate to high immune cell infiltration in their primary tumours.     

Porcine CD18 mediates Actinobacillus pleuropneumoniae ApxIII species-specific toxicity

Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, produces Apx toxins that are recognized as major virulence factors. Recently, we showed that ApxIIIA-cytotoxic activity specifically targets Sus scrofa leukocytes. Since both LtxA from Aggregatibacter actinomycetemcomitans (aggressive periodontitis in humans) and LktA from Mannheimia haemolytica (pneumonia in ruminants) share this characteristic, respectively towards human and ruminant leukocytes, and because both use the CD18 subunit to interact with their respective LFA-1, we hypothesized that ApxIIIA was likely to bind porcine CD18 to exercise its deleterious effects on pig leukocytes. A β ₂−integrin-deficient ApxIIIA-resistant human erythroleukemic cell line was transfected either with homologous or heterologous CD11a/CD18 heterodimers using a set of plasmids coding for human (ApxIIIA-resistant), bovine (-resistant) and porcine (-susceptible) CD11a and CD18 subunits. Cell preparations that switched from ApxIIIA-resistance to -susceptibility were then sought to identify the LFA-1 subunit involved. The results showed that the ApxIIIA-resistant recipient cell line was rendered susceptible only if the CD18 partner within the LFA-1 heterodimer was that of the pig. It is concluded that porcine CD18 is necessary to mediate A. pleuropneumoniae ApxIIIA toxin-induced leukolysis.     

Precursors to damascenone: synthesis and hydrolysis of isomeric 3,9-dihydroxymegastigma-4,6,7-trienes

A series of four isomeric 3,9-dihydroxymegastigma-4,6,7-trienes, 8, has been prepared. The (3S,6R,9S) isomer of 8 proved to be identical to an isomer of this compound tentatively identified as an intermediate in the formation of damascenone from an allene triol. Each of the four isomers, when hydrolyzed independently of each other at pH 3.0 and 25 degrees C, produced product mixtures in which the major product was damascenone (1). Contrary to expectation, 3-hydroxydamascone (5) was not observed in any of the hydrolyses. Consequently, the mechanism of formation of damascenone proposed earlier requires modification. In each hydrolysis, the product mixtures showed the presence of a second isomer of 8, produced by epimerization during hydrolysis. Chiral analysis on a Cyclosil B column revealed that this epimerization was occurring at C(3) in each of the hydrolyses.     

Detection of antibodies and risk factors for infection with bovine respiratory syncytial virus and parainfluenza virus 3 in dual-purpose farms in Colima, Mexico

A cross-sectional study was carried out, from November 2007 to March 2008, to estimate the prevalence of and to determine risk factors associated with bovine syncytial respiratory virus (BRSV) and parainfluenza 3 virus (PIV3) in dual-purpose herds in Colima, México. One hundred and seventy-six sera from 33 herds for PIV3 and 232 sera from 44 herds for BRSV were used. Sera were analyzed by indirect ELISA for the detection of antibodies against BRSV and PIV3 in cattle herds to determine the seroprevalence of respiratory diseases. The apparent and true prevalences for PIV3 were 60.8% and 54.4% and for BRSV 52.2% and 50.8%, respectively. The percentage of herds showing at least one positive animal was 78.7% for PIV3, and 93.2% for BRSV. Age (≤12, 13-48, and >48?months old) and respiratory signs (no, yes) showed significant association (P?相似文献   

Assessment of gut microbiota in different developmental stages of Malaysian Mahseer (Tor tambroides)

Malaysian Mahseer (Tor tambroides) has a good prospect for aquaculture because of its high market demand. However, there is a scarce information on gut microbiota associated with Malaysian Mahseer unlike other fish species. Therefore, we constructed and compared gut microbiota in different developmental stages (larval, juvenile, fingerling, yearling, and adult) using culture dependent and PCR‐DGGE fingerprinting technique for better understanding of gut microbiota composition associated with T. tambroides. Culturable gut microbiota composition in all developmental stages were composed of β‐ and γ‐Proteobacteria, and Bacilli. Biodiversity analysis of culturable gut microbiota showed that larval, juvenile, and adult stages have higher diversity than fingerling and yearling stages. Ward's linkage cluster analysis showed that culturable gut microbiota composition in larval and juvenile stages were close to adult stages, whereas fingerling and yearling stage composed same cluster. PCR‐DGGE fingerprinting technique showed that unculturable gut microbiota were constituted by α‐and γ‐Proteobacteria, and Actinobacteria. Ward's linkage cluster analysis showed that unculturable gut microbiota composition in both larval and juvenile stages were distinct from other developmental stages. Our results revealed that gut microbiota composition were varied in different developmental stages of Malaysian Mahseer and continuous shifts of gut microbiota from larval to adult stages.