Laboratory diagnosis of canine GM2-gangliosidosis using blood and cerebrospinal fluid.

In the present study, laboratory techniques were used to diagnose canine GM2-gangliosidosis using blood and cerebrospinal fluid (CSF) that can be collected noninvasively from living individuals. Lysosomal acid beta-hexosaminidase (Hex) was measured spectrofluorometrically using 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide and 4-methylumbelliferyl 7-(6-sulfo-2-acetamido-2-deoxy-beta-D-glucopyranoside) as substrates. Main isoenzymes A and B of Hex in leukocytes were also analyzed using cellulose acetate membrane electrophoresis. GM2-ganglioside in CSF was detected and determined quantitatively by using thin-layer chromatography/enzyme-immunostaining method with anti-GM2-ganglioside antibody. In normal dogs, Hex activities could be determined in leukocytes, serum, and CSF and the total activities were markedly reduced in all the enzyme sources in a dog with Sandhoff disease. Electrophoresis of a leukocyte lysate from a normal dog showed that the Hex A and Hex B were not separated distinctively with formation of a broad band, whereas there were no bands in electrophoresis of a lysate from a dog with Sandhoff disease, showing a deficiency in the total enzyme activity. GM2-ganglioside could be detected and determined quantitatively in as little as 100 microl of canine CSE GM2-ganglioside in CSF in a dog with Sandhoff disease increased to 46 times the normal level. In conclusion, the methods in the present study are useful for diagnosis of canine GM2-gangliosidosis. These techniques enable definitive and early diagnosis of canine GM2-gangliosidosis even if tissues and organs cannot be obtained.     

Influence of acute exposure to a low dose of systemic insecticide fipronil on locomotor activity and emotional behavior in adult male mice

Fipronil (FPN) is a systemic insecticide that antagonizes the gamma-aminobutyric acid type A (GABA_A) receptors in insects. Recently, adverse effects of FPN on mammals have been reported, but most of those were caused by high doses of FPN and additives in the products. We investigated the effects of low-dose pure FPN on the emotional behavior of mice. Nine-week-old male mice conducted behavioral tests 24 hr after FPN administration by gavage at doses of 0.05 or 5 mg/kg based on the no-observed-effect level (NOEL), showed a significant increase in locomotor activity and dose-dependent responses on the time they spent in the central zone in the open field test. Pure FPN below the NOEL dose may affect the emotional behavior of mice.     

Involvement of a host erythrocyte sialic acid content in Babesia bovis infection

Host sialic acid (SA) has recently been suggested to play an important role in erythrocyte (RBC) infection by Babesia spp. The present study attempted to further determine the specific type of SAs important in the RBC invasion. Bovine RBC was found to bear abundant alpha2-3-linked SA residues but not alpha2-6-linked SA in nature, confirmed by flow cytometric analysis of the neuraminidase (Nm)-treated RBCs. Lectin-blot analyses revealed the removal of alpha2-3-linked SAs from the 97-, 33-, and 31-kDa bands by the Nm treatment. Addition of the Nm-treated RBCs into an in vitro culture of B. bovis resulted in a decreased population of the parasitized RBCs. The thin smear samples from the cultures were then observed under a confocal laser scanning microscope after staining with the alpha2-3-linked SA-specific lectin: a selective invasion of B. bovis was found only in the intact RBCs bearing the SAs, but not in the desialylated RBCs. Furthermore, a significant reduction of the parasitized RBCs was also observed in the culture supplemented with exogenous 3'-sialyllactose containing the alpha2-3-linked SAs. However, the complete inhibition of parasite proliferation was not achieved in the culture. These findings indicate that while the alpha2-3-linked SA-dependent pathway is needed for highly efficient invasion of host RBCs by B. bovis, there might also be other potential alternative pathways.     

Treatment of cow-waste slurry by a microbial fuel cell and the properties of the treated slurry as a liquid manure

Resource recycling and the proper treatment of animal waste to reduce its environmental impact are currently important issues for the livestock industry. A microbial fuel cell (MFC), a new type of bioreactor, is expected to play roles in both waste‐water purification and energy recovery. However, the generation of electricity from cow waste has not yet been examined. In this study, using an MFC, we examined the possibility of generating electricity from dairy‐cow waste slurry, and analyzed the properties of the treated slurry as liquid manure for resource recycling. The MFC treatment of the slurry generated electricity in a dose‐dependent manner, and the maximum power output by the MFC from a 1 g of chemical oxygen demand/L slurry was 0.34 mW/m². After the MFC treatment, 84% of the biological oxygen demand in the slurry was removed and three essential fertilizer elements (nitrogen, phosphorus, and potassium) were retained at 84, 70, and 91% levels, respectively. The amount of ammonia nitrogen in the slurry, as an element of fast‐release fertilizer, was increased by 1.9‐fold. Although the treated slurry displayed properties that made it preferable as liquid manure, further studies to improve the electrical power output by the MFC are required for practical use.     

Calcium ions are involved in egress of Babesia bovis merozoites from bovine erythrocytes

Bovine babesiosis is a livestock disease known to cause economic losses in endemic areas. The apicomplexan parasite Babesia bovis is able to invade and destroy the host’s erythrocytes leading to the serious pathologies of the disease, such as anemia and hemoglobinuria. Understanding the egress mechanisms of this parasite is therefore a key step to develop new therapeutic strategies. In this study, the possible involvement of Ca²⁺ in the egress of B. bovis merozoites from infected erythrocytes was investigated. Egress was artificially induced in vitro using calcium ionophore A23187 and thapsigargin to increase Ca²⁺ concentration in the cytosol of the parasite cells. The increased intracellular Ca²⁺ concentration following these treatments was confirmed using live cell Ca²⁺ imaging with confocal laser scanning microscopy. Based on our findings, we suggest a Ca²⁺ signalling pathway in the egress of B. bovis merozoites.     

Synovial fluid total protein concentration as a possible marker for canine idiopathic polyarthritis

Idiopathic polyarthritis (IPA) is a very common inflammatory arthropathy in the dog. Canine IPA is diagnosed mainly by detecting increased number of leukocytes in the synovial fluid (SF), which is easily influenced by glucocorticoid therapy. We obtained 31 SF samples from 24 IPA dogs prior to (n=19) and/or after (n=12) 1 to 10 weeks of glucocorticoid therapy. The SF total protein concentrations of IPA dogs were significantly higher than those of dogs with non-arthritis diseases (n=34) and healthy controls (n=10). Our data revealed that the SF total protein concentrations are not influenced by several weeks of glucocorticoid therapy. Hence, the SF total protein concentration is applicable as a diagnostic marker of canine IPA even when the patients are receiving glucocorticoid therapy.     

Optimal dietary taurine level for growth of juvenile Japanese flounder Paralichthys olivaceus

The requirement for taurine in juvenile Japanese flounder Paralichthys olivaceus was determined by feeding diets containing various levels of taurine and cystine. Test diets supplemented with 0.5, 1.0 and 1.5% of taurine or with 0.5, 1.0 and 1.5% of L -cystine were prepared. The basal diet contained 55% protein from white fish meal. These diets were fed to juvenile Japanese flounder with an initial mean bodyweight of 0.9 g (total length (TL) 48 mm) for 5 weeks. Approximately 1.4% taurine content in the diet was required for optimum growth of juvenile flounder. A positive linear relationship was noted between the content of taurine accumulated in the muscle, liver and brain and the level of taurine in the diet. However, there was no increased taurine content in tissues of fish fed the cystine-supplemented diet. In contrast, the fish fed control and cystine-supplemented diets showed higher contents of cystathionine in the tissues. The concentration of cystathionine in tissues rapidly decreased with an increase of taurine in the diet. It was also observed that for each of the dietary groups, a trace amount of taurine was excreted. These results suggest that the taurine content in the diet affects the sulfur amino acid metabolism of juvenile Japanese flounder, and indicate that juvenile flounder are unable to biosynthesize taurine from cystine.     

Evaluation of shrimp polyculture system in Thailand based on stable carbon and nitrogen isotope ratios

ABSTRACT: To quantify the contribution by cocultured animals to waste assimilation in an intensive shrimp farm in Thailand, the food web structures of the macrobenthos in a reservoir pond, a shrimp culture pond and water treatment ponds were examined using the stable C and N isotope ratio technique. Seawater for aquaculture was drawn from a creek, and stored in a reservoir pond, used for farming the banana prawn Fenneropenaeus merguiensis in culture ponds, and then recycled through treatment ponds where the green mussel Perna viridis was cultured to remove organic wastes discharged from the farming. The clam worm Nereididae sp. and the mud creeper Cerithideopsilla cingulata in the culture pond had δ ¹³C values of −21.0‰ and −18.4‰, respectively, suggesting that shrimp feed (mean δ ¹³C = −20.7‰) was the main food source for these species. The δ ¹³C analysis also suggested that sediments (−23.7‰) in the reservoir pond and particulate organic matter (POM) (−24.0‰) and/or sediments (−25.0‰) in the treatment pond supplied carbon for most macrobenthic animals. However, green mussels in the treatment pond had a mean δ ¹³C value of −20.5‰, suggesting that shrimp feed was the main food source for this species.