Substrate-controlled succession of marine bacterioplankton populations induced by a phytoplankton bloom

Phytoplankton blooms characterize temperate ocean margin zones in spring. We investigated the bacterioplankton response to a diatom bloom in the North Sea and observed a dynamic succession of populations at genus-level resolution. Taxonomically distinct expressions of carbohydrate-active enzymes (transporters; in particular, TonB-dependent transporters) and phosphate acquisition strategies were found, indicating that distinct populations of Bacteroidetes, Gammaproteobacteria, and Alphaproteobacteria are specialized for successive decomposition of algal-derived organic matter. Our results suggest that algal substrate availability provided a series of ecological niches in which specialized populations could bloom. This reveals how planktonic species, despite their seemingly homogeneous habitat, can evade extinction by direct competition.     

Characterization of the immune response of domestic fowl following immunization with proteins extracted from Dermanyssus gallinae

Dermanyssus gallinae is the most significant ectoparasite of European poultry egg laying production systems due to high costs of control and associated production losses as well as adverse effects on bird welfare. In this study, soluble proteins were extracted from unfed D. gallinae (DGE) using a urea-based detergent and ultra-filtration, passed through a 0.22 μm filter and blended aseptically with adjuvant. One group of laying hens was immunized with DGE and adjuvant (Montanide ISA 50 V) whilst another group (Control) received physiological saline and adjuvant. All birds were immunized on two occasions, 21 days apart. Antibody response to immunization was determined by ELISA and western blotting using immunoglobulins (Igs) extracted from egg yolk. DGE immunization of hens resulted in a significant (P < 0.05) IgY response compared to controls, although there was no significant difference in IgM response between treatments. A number of proteins were identified by western blotting using IgY antibodies from DGE immunized birds, most prominently at 40 and 230 kDa. Analysis of proteins from approximately corresponding bands on SDS-PAGE confirmed the identity of tropomyosin, whilst other proteins showed high sequence homology with myosin and actin from other arachnid and insect species. Immunization of hens with DGE resulted in a 50.6% increase in mite mortality (P < 0.001) 17 h after feeding when tested by an in vitro mite feeding model. Data in this study demonstrate that somatic antigens from D. gallinae can be used to stimulate a protective immune response in laying hens. Further work is needed to identify other proteins of interest that could confer higher protection against D. gallinae, as well as optimization of the vaccination and in vitro testing protocol.     

Factors associated with the career path choices of veterinarians in western Canada

This second of 2 articles, relating to the veterinary profession in western Canada, explores the factors associated with veterinarians’ career path choices. Among other factors, companion animal (small animal and equine) (CA) practitioners were less likely to have been raised in, or near to, a small center (≤ 10 000), were more concerned with their workload (hours of work and number of nights on-call), and preferred to work in progressive practices. Food animal (FA) practitioners were more likely to be male, have been raised in a small center, have been raised in the Province of Saskatchewan, and to have self-assessed themselves as having an above average knowledge of agriculture at the time they applied for admission to veterinary college. Mixed animal (MA) practitioners had more factors in common with FA than with CA practitioners. Three main factors were associated with leaving mixed or food animal practice: hours of work and too many nights on-call, the level of remuneration, and lack of support and mentorship.     

Inflammatory mammary carcinoma in 12 dogs: Clinical features, cyclooxygenase-2 expression, and response to piroxicam treatment

Canine inflammatory mammary carcinoma (IMC) is a rare, locally aggressive, highly metastatic tumor that is poorly responsive to treatment. The purposes of this study were to retrospectively evaluate the history, signalment, and clinical signs of dogs with IMC; compare the outcome of affected dogs treated with traditional chemotherapy with those treated with piroxicam; evaluate Cox-2 expression of IMC cells; and correlate Cox-2 expression with outcome based on treatment. Strong cyclooxygenase-2 expression was present in all tumors. Improvement in clinical condition and disease stability was achieved in all dogs treated with piroxicam, with mean and median progression-free survival of 171 and 183 days, respectively. Median survival time of 3 dogs treated with doxorubicin-based protocols was 7 days, which was significantly less than that of dogs treated with piroxicam (median, 185 days). In conclusion, piroxicam should be considered as a single agent for the treatment of dogs with inflammatory mammary carcinoma.     

In vitro culture of equine respiratory mucosa explants

An in vitro model of the upper respiratory tract of the horse was developed to investigate mechanisms of respiratory diseases. Four tissues of the upper respiratory tract of three horses were collected. Explants were maintained in culture at an air–liquid interface for 96 h. At 0, 24, 48, 72 and 96 h of cultivation, a morphometric analysis was performed using light microscopy, scanning electron microscopy and transmission electron microscopy. The explants were judged on morphometric changes of epithelium, basement membrane and connective tissue. Viability was evaluated using a fluorescent Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labelling (TUNEL) staining. No significant changes in morphometry and viability of any of the explants were observed during cultivation. Hence, the in vitro model may be useful to study infectious and non-infectious diseases at the level of the equine respiratory tract, with potential application to the development of vaccines and treatments for diseases of the respiratory tract.