Conversion of dextran to cycloisomaltooligosaccharides using an enzyme-immobilized porous hollow-fiber membrane

This paper describes a cycloisomaltooligosaccharide glucanotransferase (CITase)-multilayer-immobilized porous hollow-fiber membrane used as an enzyme bioreactor. Dextran, a substrate with an average molecular mass of 43000, is converted into seven- to nine-glucose-membered cycloisomaltooligosaccharides, effective as a preventive for dental caries, aided by convective transport of the substrate to the vicinity of the enzyme through the pores. Epoxy-group-containing graft chains were uniformly appended onto the surface of pores throughout a porous hollow-fiber membrane by radiation-induced graft polymerization. Subsequently, a diethylamino group was introduced, as an anion-exchange moiety, to the graft chains, which caused the chains to expand toward the interior of the pores due to mutual electrostatic repulsion. The expanding graft chain provided multilayer binding sites for CITase. Fifty-five milligrams of adsorbed CITase per gram of membrane is equivalent to the degree of multilayer binding of 5. Finally, 80% of the multilayer-adsorbed CITase was immobilized via enzymatic cross-linking with transglutaminase to prevent the leakage of enzymes. CITase, with a degree of multilayer immobilization of 4, produced the target cycloisomaltooligosaccharides at a conversion yield of 55% in weight at 310 K during permeation by the dextran solution at a space velocity defined as the permeation rate divided by membrane volume of 6 per hour.     

Trophodynamic structure of a swampy bog at the clymax stage of limnological succssion I. Prmary production dynamics

Effect of emergent vegetation on the population dynamics of phytoplankton community in Matsumi-ike Bog, a typical bog at the climax stage of limnological succession, was studied. The emergent vegetation grew until August and then withered and collapsed mainly during December and January, supplying the debris of emergent plants into the water column. Population density of the predominant phytoplankton showed sinusoidal fluctuation affected primarily by the water temperature, with various lag phases due to the function of other environmental factors. Shading by the emergent vegetation shifted the initiation of phytoplankton fluctuation earlier. This fluctuation patterns was most obvious among those phytoplankton contain chlorophyll-a and -b, but non -a and-c. The population dynamics were also compared with that of Matsumi-ike Bog at premature stages without (8 yr ago) or with littoral vegetations (3 yr ago). The population density of phytoplankton with chlorophyll-b decreased but those with chlorophyll-c increased, due to the shading effect of the emergent vegetation with the limnological succession of the bog. At the climax of succession, the dynamic state of phytoplankton community has become more stable.     

Neuromuscular and vascular hamartoma of the small intestine in an F344 rat

An intestinal mass was found in the border area of the jejunum and ileum of a 110-week-old male F344 rat. Histopathologically, the mass protruded into the lumen and was covered with intestinal epithelium, exhibiting a normal architecture. The lesion was located in the submucosa and consisted of loose connective tissue, smooth muscle, scattered ganglion cells, and blood vessels of various sizes. Although these components showed an irregular and disordered structure, no cellular atypia, increased proliferation activity, or invasive growth to adjacent tissues were detected. Immunohistochemical analyses revealed that smooth muscle, ganglion, and endothelial cells were positive for α-smooth muscle actin and vimentin, S-100, and CD34 and von Willebrand factor, respectively, indicating maturation of these cells. Thus, the mass was diagnosed as a neuromuscular and vascular hamartoma of the small intestine. To the best of our knowledge, this is the first report of this type of lesion in rodents.     

Impact of short-term high-fat feeding on lipid droplet content in mouse oocytes

Mature mammalian oocytes contain lipid droplets (LDs), which are neutral lipid storage organelles critically important for energy metabolism. In mice, maternal obesity, induced by long-term (> 3 months) high-fat feeding, contributes to the accumulation of LDs in mature oocytes. However, few studies have investigated the influence of short-term high-fat feeding on LD content. In this study, we demonstrated that 3 weeks of high-fat feeding is sufficient to increase LD content and intracellular triacylglycerol levels. Using a two-step centrifugation technique to release LDs into the perivitelline space, we found that short-term high-fat feeding increased the level of LDs in MII oocytes and that 3 days of high-fat feeding were sufficient to increase efficiency of LD release. Collectively, our study suggests that short-term high fat feeding can have a higher impact on lipid metabolism during oocyte maturation.     

Development of enzyme immunoassay for chromogranin A (CgA) and profiling of plasma CgA concentrations in the cow

The objectives of this study were to establish and characterize a homologous immunoassay for bovine chromogranin A (bCgA) and to profile plasma bCgA concentrations during early pregnancies. We synthesized oligopeptide corresponding to the amino acid sequence 341–355 of bCgA for immunizing rabbits and peptide corresponding to the amino acid sequence 336–365 of bCgA for both a biotinylated tracer and reference standards. Recombinant bCgA protein was also generated in Escherichia coli lysate. Dose-dependent displacement curves were obtained from 1 to 1,000 nM of the reference standards. The displacement curves showed a good relationship between the reference standards of the synthetic peptide and the serially diluted plasma sample or recombinant bCgA protein generated in the present study. The assay sensitivity defined as the value of two standard deviations below the zero standard was calculated as 0.46 nM. The intraassay and interassay coefficients of variation were 6.48% and 13.4%, respectively. Changes in the plasma bCgA concentrations in early pregnancies undulated in nonpregnant animals. The results of the present study suggest that assaying plasma bCgA concentrations could be utilized as measures to evaluate the physiological status of cattle.     

Lingual squamous cell carcinoma in a California sea lion (Zalophus californianus).

A 28-yr-old female California sea lion (Zalophus californianus) in a commercial aquarium developed an ulcerated lingual tumor and died. Necropsy revealed a moderately differentiated squamous cell carcinoma. Immunohistochemical staining and electron microscopic studies revealed that the tumor cells were strongly positive with anti-keratin-cytokeratin antibody and had abundant tonofibrils and desmosomes. The neoplasm had metastasized to a mandibular lymph node.     

A case study of improving milking cow performance and milking system performance with using a flow simulator

Efforts to improve dairy performance have been focused on increasing milk productivity of cows through improved feeding systems and genetic potential. However, methods for evaluating milking system performance based on milk productivity have not yet been established. Milking system performance was evaluated by measuring the claw vacuum at five flow rates (1.9–8.7 kg/min) produced using a flow simulator for a single eight‐swing milking parlor with a high‐line system. Based on these results, a double eight‐parallel milking parlor with a low‐line system was installed and tested. Farmers can take data obtained from evaluations of milking system performance into account for future management decisions, such as renewing the milking system. By renewing the milking system, average milking productivity, somatic cell linear score (LS) of bulk milk, and LS of each cow were significantly improved in the year after installing the new system (p < .01). In addition to checking conventional milking systems, this novel diagnostic method using a flow simulator can be used for checking new installations and also for proposing renovations.     

Mercury Speciation in the Water of Minamata Bay, Japan

The speciation of mercury (Hg) in Minamata Bay (Japan) was studied over a 2-year period (2006?C2008). Concentrations of dissolved total Hg, dissolved methylmercury (MeHg), particulate total Hg, and suspended solids were 0.43?±?0.14 ng/l (mean?±?standard deviation), 0.10?±?0.06 ng/l, 3.04?±?2.96 ng/l, and 5.94?±?2.10 mg/l, respectively. Correlations between concentrations of particulate total Hg and suspended solids at four depths (surface: 0 m; mid-depth: ?6 m, ?10 m; and bottom +1 m layer) were only significant in the bottom +1 m layer. The mean dissolved MeHg concentration and the ratio of dissolved MeHg to dissolved total Hg were considerably higher in summer compared to other seasons. The data suggest that bottom sediment was not the sole source of MeHg, and that MeHg may be produced in the water column by the conversion of divalent Hg eluted from resuspended bottom sediment. The correlation between seawater characteristics such as salinity, temperature, dissolved oxygen (DO), and dissolved MeHg concentration indicates that Hg methylation could be influenced by the heterotrophic activity of microorganisms in the seawater. In particular, inverse correlations were observed between DO, salinity, and MeHg concentration. However, dissolved MeHg concentrations did not correlate with seawater characteristics such as pH or chlorophyll-a.