Molecular Basis of Gene-for-Gene Specificity in Bacterial Speck Disease of Tomato

Transient expression of the Pseudomonas syringae avirulence gene avrPto in plant cells resulted in a Pto-dependent necrosis. The AvrPto avirulence protein was observed to interact directly with the Pto resistance protein in the yeast two-hybrid system. Mutations in the Pto and avrPto genes which reduce in vivo activity had parallel effects on association in the two-hybrid assay. These data suggest that during infection the pathogen delivers AvrPto into the plant host cell and that resistance is specified by direct interaction of Pto with AvrPto.     

Experimental production of gastric dilation and its association with osmoregulatory stress and biogenic amines in chinook salmon, Oncorhynchus tshawytscha (Walbaum)

Chinook salmon smolt in fresh water fed a commercial diet known to produce minimal gastric dilation and air sacculitis (GDAS) were randomly assigned to four experimental tanks with flow-through sea water. All four groups were acclimatized to sea water for 3 weeks and fed a diet of minced fresh seafood. After 3 weeks the groups were fed either; seafood as before, a different commercial pelleted diet associated with the development of GDAS on farms, or either diet supplemented with 500 mg L(-1) putrescine, 300 mg L(-1) cadaverine and 250 mg L(-1) tyramine. Gastric dilation was produced in fish fed the commercial diet for 1 month but not by feeding a diet of minced seafood. The addition of putrescine, cadaverine and tyramine to either diet had no significant effect on the development of gastric dilation. Fish fed the commercial diet had significantly (P < 0.0001) wider weight-adjusted stomach widths, less prominent longitudinal stomach folds (P < 0.0001) and lower (P < 0.0001) stomach-width ratios than fish fed the fresh seafood diet. There was no significant difference in serum osmolality or sodium concentration between fish from groups with or without gastric dilation or fed biogenic amines.     

Effects of Gonadotropins on In Vitro Maturation and of Electrical Stimulation on Parthenogenesis of Canine Oocytes

The objective of this study was to determine the effects of gonadotropins on in vitro maturation (IVM) and electrical stimulation on the parthenogenesis of canine oocytes. In experiment I, cumulus oocyte complexes were collected from ovaries at a random phase of the oestrus cycle and cultured on maturation medium treated with hCG or eCG for 48 or 72 h. There were no significant differences in the effects on the metaphase II (MII) rate between the hCG and eCG treatment groups over 48 h (5.4% vs 5.5%). The MII rate in the co-treatment group of hCG and eCG for 48 h was higher than in each hormone treated group (15.5%, p < 0.05). In experiment 2, the parthenogenetic effect on oocyte development, at various electrical field strengths (1.0, 1.5, 2.0 kV/cm DC) for 60 or 80 μs with a single DC pulse after IVM on the co-treatment of hCG and eCG, was examined. The rate of pronuclear formation (37.1%) in electrical activation at 1.5 kV/60 μs without cytochalasin B (CB) was higher than that of oocytes activated in the other groups (p < 0.05). However, we did not observe the cleavage stages. Also, CB did not influence parthenogenesis of canine oocytes. The results showed that the pronucleus formation rate, indicative of the parthenogenesis start point, could be increased by electrical stimulation. Therefore, these results can provide important data for the parthenogenesis of canine oocytes and suggest the probability of parthenogenesis in canines.     

Epitheliocystis in lake trout Salvelinus namaycush (Walbaum) is associated with a β‐proteobacteria

Lake trout Salvelinus namaycush (Walbaum) raised for stocking experienced yearly (2011–13) winter epizootics of epitheliocystis. Affected fish were dispersed on the bottom of the tank, had decreased feed and fright response, and mortality often reached 40%. Peak mortality occurred within 3 weeks of the appearance of clinical signs, and outbreaks typically lasted 6 weeks. Affected fish had no gross lesions but histologically had branchial epithelial necrosis and lamellar hyperplasia, with small to large numbers of scattered epithelial cells containing 10‐ to 20‐μm inclusions. A longitudinal study was undertaken of one annual outbreak, and lamellar hyperplasia was most closely associated with mortality. The number of inclusions was statistically greater (P < 0.05) before and during peak mortality, but inclusions were present in low numbers before clinical signs occurred. Results of histochemical staining, immunohistochemistry and transmission electron microscopy supported the presence of a β‐proteobacteria rather than a Chlamydiales bacterium within inclusions. PCR primers to identify Chlamydiales did not give consistent results. However, the use of universal 16S rDNA bacterial primers in conjunction with laser capture microdissection of inclusions demonstrated that a β‐proteobacteria was consistently associated with affected gills and is more likely the cause of the disease in lake trout.     

Idiopathic haemarthrosis in eight horses

Objectives To review eight horses diagnosed with idiopathic haemarthrosis and to describe the intra‐articular use of yttrium‐90 (⁹⁰Y) and methylprednisolone acetate (MPA) in recurrent haemarthrosis cases. Design Retrospective case series. Method The medical records, diagnostic images, histopathology and outcome of all horses diagnosed with idiopathic haemarthrosis between 1998 and 2010 were reviewed. Results Four Thoroughbred racehorses with haemarthrosis of the antebrachiocarpal joint had severe acute lameness (median, grade 4) and marked joint effusion after high‐speed exercise. Another four horses (2 Thoroughbred racehorses, 1 Standardbred racehorse, 1 Warmblood) had haemarthrosis of the tarsocrural joint and presented with mild, intermittent lameness (median, grade 1) and marked, persistent joint effusion. Six of the eight horses had recurrent haemarthrosis prior to treatment. Radiographic and nuclear scintigraphic examinations did not identify bone pathology. Diagnostic arthroscopy (7 cases) identified grossly hypertrophied yellow/brown discoloured synovium. Synovial histopathology of these cases revealed chronic synovial hyperplasia with severe haemosiderosis and granulomatous inflammatory reaction of varying severity. All horses underwent rest, bandaging and phenylbutazone administration. Two horses had subtotal mechanical synovectomy, four horses had intra‐articular administration of ⁹⁰Y and MPA, and one horse underwent both treatments. Seven cases returned to their previous use (median time, 7 months). Haemarthrosis recurred in three horses, two of which had received the ⁹⁰Y and MPA treatment. Conclusion Idiopathic haemarthrosis should be considered a differential for acute and recurrent joint related lameness and effusion. Recurrence appears not uncommon and the use of intra‐articular ⁹⁰Y and MPA in conjunction with a conservative management treatment protocol warrants further evaluation.     

Neoplasia of captive yellow sea horses (Hippocampus kuda) and weedy sea dragons (Phyllopteryx taeniolatus)

Syngnathidae is the family of fish that includes sea horses, pipefish, and sea dragons. To date, only a single publication has described neoplasia in syngnathids, a fibrosarcoma of the brood pouch in an aquarium-reared lined sea horse (Hippocampus erectus). From 1998 until 2010, the Toronto Zoo submitted 172 syngnathids for postmortem; species included the spotted or yellow sea horse (Hippocampus kuda), the pot-bellied sea horse (Hippocampus abdominalis) and the weedy sea dragon (Phyllopteryx taeniolatus). Seven neoplasms and two neoplastic-like lesions were identified from these cases. Under light microscopy, the neoplasms had morphological characteristics of a cardiac rhabdomyosarcoma, renal adenocarcinoma, renal adenoma, renal round cell tumors, which were likely lymphomas, exocrine pancreatic carcinoma, and intestinal carcinoma. Of these neoplasms, four had clear evidence of metastasis: the pancreatic and intestinal carcinomas and both round cell tumors. As syngnathids are highly fastidious animals, they can be difficult to maintain in captivity. In order to improve their husbandry, preventative and palliative care, as well as treatment, it is important to investigate and document the types of diseases affecting syngnathids.     

Effects of iodine methionine on boar sperm quality during liquid storage at 17°C

Microbial environment is one of the important factors that affect the quality of preserved semen. Iodine methionine (IM), participating in the production and activation of metabolic enzymes, is a new type of amino acid chelate. To date, there has been no report to evaluate the effects of IM on boar semen preservation at 17°C. This study was designed to investigate the effects of IM on boar sperm quality and reproductive performance during liquid storage at 17°C and its antibacterial effect. Semen samples collected from six Yorkshire boars were diluted with basic liquid containing different concentrations of IM (0, 20, 40, 80, 160 and 320 μM). Subsequently, sperm motility, plasma membrane integrity and acrosome integrity were determined. After 6 days of preservation, the difference in microbial composition between control group and 80 μM IM group was compared using 16S rDNA sequencing, and the effects of IM on reproductive performance were also compared and analysed between the two groups. The results demonstrated that 20, 40 and 80 μM IM improved boar sperm motility, plasma membrane integrity and acrosome integrity. 80 μM IM was the optimum concentration. Conversely, 160 and 320 μM IM resulted in deleterious consequences to boar sperm quality compared to the control group and other treatment groups (p < .05). After 6 days of preservation, sperm motility, plasma membrane integrity and acrosome integrity were 56.0%, 51.8% and 59.4%, respectively. There was no significant difference in non‐return rate between the two groups (p > .05). But the litter size of 80 μM IM group was significantly higher than that of control group (p < .05). 80 μM IM inhibited proliferation of the phylum Proteobacteria and the genus Staphylococcus as well as Pseudomonas (p < .05). Further studies are required to understand the antibacterial mechanism of IM in liquid‐preserved boar semen.