Response of enzyme activities and metabolic intermediate concentrations to epinephrine administration in hepatopancreas and muscle of carp

SUMMARY: Common carp Cyprinus carpio were administered intraperitoneally with 10 μmol epinephrine per 100 g bodyweight, and enzyme activities and metabolic intermediate concentrations were determined in the hepatopancreas and muscle. Glycogen phosphorylase a (GPase a) activity together with cyclic AMP (cAMP) concentration was increased, and glycogen content was decreased in the hepatopancreas and muscle at 2 h after the administration. The epinephrine administration also increased hepatopancreatic glucose-6-phosphatase and fructose-1,6-biphosphatase activities as well as serum glucose, lactate, and free amino acid concentrations. Furthermore, its administration increased phosphofructokinase activity together with lactate, fructose-6-phosphate, adenosine-5'-monophosphate, and adenosine-5'-diphosphate concentrations and decreased citrate concentration in the muscle. Thereafter, almost all parameter concentrations in the hepatopancreas and muscle recovered to the pre-administered levels during 24 h after the administration. These results suggest that epinephrine administration enhanced glycogenolysis and gluconeogenesis in the hepatopancreas, and released glucose into the bloodstream to supply it to the muscle. The blood glucose together with muscle glycogen seems to be metabolized through enhanced glycolysis in the muscle.     

Anesthesia,fasting tolerance,and nutrient requirement of juvenile northern bluefin tuna

ABSTRACT:   The present study aimed to investigate a suitable anesthesia protocol for nutritional studies, fasting tolerance, and nutrient requirements for maintenance in juvenile northern bluefin tuna Thunnus orientalis weighing 0.8–0.9 g. The fish grew in a mass seedling production under completely controlled aquaculture. The solution of 0.2 mL 2-phenoxyethanol/L prepared by filtered seawater has been notably estimated as a anesthesia protocol for the juvenile, due to a shorter mean time necessary for anesthesia and recovery and higher survival rate at 24 h after recovery. All other anesthetics, 0.1 and 0.3 mL 2-phenoxyethanol/L, 0.05, 0.1 and 0.2 mL 4-allyl-2-methoxyphenol/L, and cool water temperature shocks at 16.8, 12.6 and 10.4°C, were inferior. In a 5-day tolerance test, the juvenile was fed sand lance Ammodytes personatus through the rearing period or fasted for 2, 3, 4 and 5 consecutive days. Survival rates were about 80 or 60, 50, 10 and 0%, respectively. From the relationships between days fasting and energetic and nutritional retentions, juvenile tuna require about 142.7 kJ, 5.46 g protein and 0.44 g fat/kg body weight a day for maintenance, indicating remarkably higher requirements than other aquaculture fish.     

Intraperitoneal injection of sulfur amino acids enhance the hepatic cysteine dioxygenase activity in rainbow trout (Oncorhynchus mykiss)

As part of the investigation into cysteine metabolism in fish, sulfur amino acids and their derivatives were injected intraperitoneally to fingerling rainbow trout (Oncorhynchus mykiss) to examine how the doses of these compounds affect the hepatic cysteine dioxygenase [EC 1.12.11.20] in this species. A dose of 0.25 mmol L-cysteine per 100 g body weight induced the enzyme activity as much as 2.5 times that of the control fish within 4h after the injection. The activity increased proportionally to the increasing dose of cysteine up to the dose of 0.15 mmol per 100 g body weight. The induction was observed to be rather specific to L-cysteine. These findings suggested that the cysteine sulfinate pathway might play an important role in the metabolism of excess cysteine in rainbow trout. The dosage of L-cysteine larger than 0.50 mmol per 100g body weight led to mortality of the fish. The pathway of cysteine catabolism was considered to function to prevent toxic accumulation of cysteine in rainbow trout, as in the case of mammals.     

In Situ Detection of Antibiotic Amphotericin B Produced in Streptomyces nodosus Using Raman Microspectroscopy

The study of spatial distribution of secondary metabolites within microbial cells facilitates the screening of candidate strains from marine environments for functional metabolites and allows for the subsequent assessment of the production of metabolites, such as antibiotics. This paper demonstrates the first application of Raman microspectroscopy for in situ detection of the antifungal antibiotic amphotericin B (AmB) produced by actinomycetes—Streptomyces nodosus. Raman spectra measured from hyphae of S. nodosus show the specific Raman bands, caused by resonance enhancement, corresponding to the polyene chain of AmB. In addition, Raman microspectroscopy enabled us to monitor the time-dependent change of AmB production corresponding to the growth of mycelia. The Raman images of S. nodosus reveal the heterogeneous distribution of AmB within the mycelia and individual hyphae. Moreover, the molecular association state of AmB in the mycelia was directly identified by observed Raman spectral shifts. These findings suggest that Raman microspectroscopy could be used for in situ monitoring of antibiotic production directly in marine microorganisms with a method that is non-destructive and does not require labeling.     

Dissolved inorganic nitrogen cycling in Banzu intertidal sand-flat,Japan

The sediment-water exchange of nitrogen, nitrification, denitrification and sedimentary oxygen production were simultaneously measured in the Banzu intertidal sand-flat, Tokyo Bay, Japan. The exchange flux across the sediment-water interface showed a sink of dissolved inorganic nitrogen (DIN) in the light. However, in the dark, the intertidal sediment acted as a source. The diffusive flux obtained by the ammonium profile explained only 22% of the source flux directly measured in the dark, suggesting that bioturbation or excretion by macrofauna greatly contributed to the exchange flux. The total microphytobenthic uptake of DIN estimated from O2 productivity and the Redfield ratio was 573.4 ± 64.4 mol N m2 h-1, 31% (175.9 ± 64.4 mol N m-2 h-1) of which was assumed to be derived from the overlying water. The release rate of DIN from the sediment to the water column (1.1 mmol N m-2 day-1) was balanced with the removal rate of DIN from the water column by benthic microalgae on a diurnal basis. This result suggests that DIN was recycled within the sediment, and the microalgae on the sediment surface played a significant role in suppressing the release of mineralized DIN from the sediment. The measured denitrification rate using an acetylene inhibition technique was 99.6 ± 23.5 mol N m-2 h-1. Since the direct supply of nitrate or nitrite from the water column only accounted for 27% of the total denitrification at the highest estimate, nitrogenous oxide in the sediment pool was the major contributor to sedimentary denitrification.     

Conversion to docosahexaenoic acid-containing phosphatidylserine from squid skin lecithin by phospholipase D-mediated transphosphatidylation

Phospholipase D (PLD)-mediated transphosphatidylation of squid skin lecithin with L-serine was examined to prepare docosahexaenoic acid-containing phosphatidylserine (DHA-PS). When a biphasic system with organic solvent and 0.2 M acetate buffer (pH 5.5) was used, PS synthesis was significantly affected by the amount of 3.4 M L-serine-containing acetate buffer. L-Serine concentration in the acetate buffer and choice of organic solvent were also crucial. In a typical reaction with 0.8 unit of PLD (Streptomyces sp.), 2.5 mL of ethyl acetate substrate solution containing 30 mg of squid skin lecithin in combination with 3 mL of 3.4 M L-serine-containing 0.2 M acetate buffer (pH 5.5), PS content in the recovered phospholipid fraction increased to 43.1% after 24 h. DHA composed 37.6% of fatty acids in the converted PS. This was the same DHA level as in the substrate. Phosphatidylcholine (squid skin PC, DHA 44.2%) in the squid skin lecithin was more effectively converted to PS than phosphatidylethanolamine.     

Hepatozoonosis in two species of Japanese wild cat

Hepatozoon sp. infections were detected in two species of Japanese wild cat, Iriomote wild cat (Felis iriomotensis) and Tsushima leopard cat (Felis bengalensis euptilura), between April 1993 and October 2005. The prevalence was 56.7% (17/30) and 14.3% (6/42), respectively. The most affected organ was the heart; all infected animals had organisms in their hearts. The parasitizing form was schizont and various developmental stages were observed. The size of schizont and merozoite was 22.3 +/- 3.1 x 15.3 +/- 2.2 mum and 6.1 +/- 0.6 x 2.3 +/- 0.2 mum, respectively. Few inflammatory reactions against the parasites were observed. Electron microscopically, organisms were located in parasitophorous vacuoles of unidentified host cells, and mature schizonts consisted of numerous merozoites. This is the first report of hepatozoonosis in Japanese felids.     

Effects of days on feed,roughage sources and inclusion levels of grain in concentrate on finishing performance and carcass characteristics in cull beef cows

An experiment was conducted with 16 Japanese Black cows to determine the effects of different days on feed (89, 208, 271 and 341 days), inclusion levels of grain in concentrate (60% vs. 40%; dry matter (DM) basis) and roughage sources (hay vs. rice straw) on finishing performance. Additional four cows were slaughtered at 0 days on feed to obtain non‐fed carcass data. Maximum carcass weights were observed in cows fed for 271 days; an increase in carcass weight of only 14 kg was shown from 208 days to 271 days. The marbling score increased (P < 0.05) with days on feed. The percentage of fat in the subprimal rib linearly increased (P < 0.05) with days on feed. The percentage of lean meat was higher (P < 0.05) for cows fed rice straw than for cows fed hay as a roughage source. Increasing the days on feed decreased (P < 0.05) the yellowness of the fat. The effects of the inclusion levels of grain in concentrate on the finishing performance of cows were lower than the other two factors. In conclusion, feeding improves carcass values, but feeding over 208 days is an inefficient system of production in cows.     

Spontaneous Gingivitis Related to Hair Penetration in Rats

Maxillary gingivae from male and female Crl:CD(SD) rats at 12, 16, 21, and 34 weeks of age were examined histologically. The incidence of gingivitis was approximately 40%, with no age or sex predilection, and was most frequent between the first and second molar. Lesions were characterized by acute focal neutrophilic infiltration into the gingival mucosa, occasionally with inflammatory exudate. In severe cases, inflammation extended to the periodontal ligament with abscess formation, and adjacent alveolar bone destruction/resorption. The most characteristic finding was the presence of hair shafts associated with the lesion, which was observed in approximately 80% of the rats with gingivitis. These findings suggest that molar gingivitis occurs in rats from an early age and persists thereafter, and that the main cause of gingivitis in rats is hair penetration into the gingiva. It would be prudent to keep these background lesions in mind as potential modifiers in toxicity studies.