Isolation and partial characterisation of four novel plasma lectins from the American lobster Homarus americanus.

Although numerous haemolymph-derived crustacean lectins are described, few have been reported for the American lobster Homarus americanus. In the present study, affinity chromatography was used to isolate and partially describe the carbohydrate affinity of four new lectins from H. americanus plasma. HaMBP and HaDNABP were homodimers of approximately 30 kDa subunits which bound to mannan- and DNA-agarose columns, respectively. These proteins had partially overlapping elution profiles, and both shared and unique amino acid sequences and fragmentation patterns after trypsin digestion. A third homodimer of approximately 29 kDa subunits eluted with HaMBP and HaDNABP under certain conditions. HaNBP occurred as a monomer and dimer of approximately 40 kDa subunits and was recovered in relatively large quantities from mannan-agarose with N-acetylated sugars. Transmission electron microscopy revealed HaNBP to be a linear protein composed of multiple globular subunits.

Ulcerative enteritis in Homarus americanus: case report and molecular characterization of intestinal aerobic bacteria of apparently healthy lobsters in live storage.

An intermoult male American lobster, Homarus americanus, with severe intestinal lesions was encountered while collecting samples of aerobic intestinal bacteria from lobsters held in an artificial sea-water recirculation aquarium system. Grossly, the intestine was firm, thickened, and white. Histologic examination revealed a severe, diffuse, ulcerative enteritis which spared the chitin-lined colon, somewhat similar to hemocytic enteritis of shrimp. The bacterial isolates from this lobster were compared to 11 other lobsters lacking gross intestinal lesions. Two organisms, one identified as Vibrio sp. and another most similar to an uncultured proteobacterium (98.9%), clustering with Rhanella and Serratia species using 16S rDNA PCR, were isolated from the intestines of the 11, grossly normal, lobsters and the affected lobster. An additional two intestinal isolates were cultured only from the lobster with ulcerative enteritis. One, a Flavobacterium, similar to Lutibacter litoralis (99.3%), possibly represented a previously described commensal of the distal intestine. The second, a Vibrio sp., was unique to the affected animal. While the etiology of the ulcerative enteritis remains undetermined, this report represents the first description of gross and histologic findings in H. americanus of a condition which has morphologic similarities to hemocytic enteritis of shrimp. An additional observation was a decrease in the number of intestinal isolates recovered from the 11 apparently healthy lobsters compared to that previously reported for recently harvested lobster. More comprehensive studies of the relationship between the health of lobsters, gut microbial flora and the husbandry and environment maintained within holding units are warranted.

Isolation and characterisation of two antimicrobial peptides from haemocytes of the American lobster Homarus americanus.

Two antimicrobial peptides from haemocytes of the American lobster, Homarus americanus H. Milne Edwards 1837, were isolated and partially characterised - the first such description for this species. CAP-2, an approximately 12kDa peptide, contained amino acid sequences corresponding to the predicted sequence for Hoa-crustin. Crustins are whey acidic protein (WAP) domain - containing peptides isolated from crustacean haemocytes. CAP-2 did not have any activity towards the Gram positive coccus Aerococcus viridans unlike carcinin, a crustin from Carcinus maenas haemocytes, which may partially explain the lobster's susceptibility to this bacterium. A second peptide, CAP-1, was a multimer composed of 4-6kDa subunits with similarities to amphibian temporins. CAP-1 may represent a novel group of antimicrobial peptides for marine invertebrates and has been tentatively named 'homarin'. Homarin had bacteriostatic activity against some Gram negative bacteria and both protozoastatic and protozoacidal activity against two cultured scuticociliate parasites Mesanophrys chesapeakensis and Anophryoides haemophila, the latter a significant pathogen of H. americanus.

Apparent pseudohyperkalemia in a Chinese Shar Pei dog.

Whole blood in a serum clot tube and EDTA-anticoagulated samples from an 8-year-old spayed female Chinese Shar Pei dog were submitted by an external clinic to the diagnostic laboratory at Atlantic Veterinary College for routine biochemical and hematologic analysis prior to entropion surgery. Laboratory abnormalities included mild hyperkalemia (6.3 mmol/L, reference interval 3.6-6.0 mmol/L), mild normocytic, hypochromic, nonregenerative anemia (HCT 0.31 L/L, reference interval 0.37-0.55 L/L; MCHC 290 g/L, reference interval 320-360 g/L), and increased red cell distribution width (RDW; 26.2%, reference interval 11-14%). A small subpopulation of macrocytic, slightly hypochromic erythrocytes was noted on Wright's-Giemsa-stained blood smears. Biochemical and hematologic data obtained from this patient over the previous 7.5 years indicated that serum (and in 1 case, heparinized plasma) potassium concentration was increased (range, 6.3-10.9 mmol/L) in 5 of 8 samples (HCT ranged from 0.31-0.43 L/L, Hgb 91-124 g/L, MCHC 280-312 g/L, and RDW 18.2-26.9%). Clinical signs suggestive of hyperkalemia were not observed at any time, suggesting pseudohyperkalemia as the cause of the increased potassium concentrations. An erythrocyte lysate prepared from a heparinized blood sample had a high potassium concentration (16.8 mmol/L) compared with that of a clinically healthy, non-Shiba control dog (6.7 mmol/L). An osmotic fragility test of the patient's erythrocytes showed 50% hemolysis at 0.57% NaCl, compared with 0.48% NaCl for the control dog, indicating increased fragility. On scanning electron microscopy, a small subpopulation of erythrocytes were large, flattened, and had a tendency to fold. These findings supported the provisional diagnosis of pseudohyperkalemia due to increased intracellular RBC potassium concentration. High-potassium erythrocytes have been reported in Akitas, Shibas, Jindos, other East Asian dog breeds, and occasionally, in mixed-breed dogs. Pseudohyperkalemia should also be considered when an otherwise unexplained elevation in serum or plasma potassium concentration is observed in Chinese Shar Pei dogs, and may be accompanied by increased RDW, low MCHC, and increased osmotic fragility with or without mild anemia.

Classification of Homarus americanus hemocytes and the use of differential hemocyte counts in lobsters infected with Aerococcus viridans var. homari (Gaffkemia).

Hemocytes of the American lobster (Homarus americanus H. Milne Edwards) were classified after examination of Wright-Giemsa stained cytocentrifuge preparations by brightfield light microscopy. Eleven hemocyte types were identified using morphologic criteria. The classification system was then used to monitor changes in the differential hemocyte count (DHC) of lobsters infected with the Gram positive coccus Aerococcus viridans var. homari, etiologic agent of gaffkemia. The appearance of less mature hemocytes in the DHCs of lobsters in the late stages of infection was similar to the 'left shift' of vertebrate inflammation. Results from this study suggest that DHCs can be used to assess and characterize inflammation in H. americanus and possibly other crustaceans.

The potential use of plasma glutamate dehydrogenase activity for the evaluation of hepatic disease in the cockatiel (Nymphicus hollandicus).

A reference interval for plasma glutamate dehydrogenase (GD) (E.C. 1.4.1.3) activity, of 0-8 IU/L, was established for the cockatiel (Nymphicus hollandicus). An automated modification of a commercial manual assay was used. This enzyme is considered liver specific in humans and numerous domestic animals, due to its organ distribution. A similar distribution was found in cockatiels in this study. Maximal enzyme activity was recovered from liver and kidney homogenate supernatants. Minimal activity was detected in skeletal muscle preparations. These results suggest a potential use for plasma GD activity in the evaluation of hepatocelluar injury/necrosis in cockatiels.