Osmoregulatory ability and stress responses during freshwater adaptation of black porgy (Acanthopagrus schlegeli) treated with exogenous prolactin

The effects of ovine prolactin (oPRL) on osmoregulatory ability (electrolyte balance, plasma osmolality and activity of gill chloride cells and gill Na⁺/K⁺‐ATPase) and stress responses (plasma cortisol, glucose, aspartate aminotransferase: AST and alanine aminotransferase: ALT) were investigated in black porgy transferred to freshwater (FW). Fish in seawater (SW) were injected twice at a 24 h interval with oPRL (at 1, 3, or 5 μg g^–1 body weight) or vehicle (0.9% NaCl) and then transferred to FW. They were sampled 3 days after the transfer. With oPRL at 5 μg g^–1, levels of plasma Na⁺ and Cl^? and osmolality were significantly higher than in saline‐treated fish, whereas gill CCs number and Na⁺/K⁺‐ATPase activity were lower. Also, the 5 μg g^–1oPRL treatment led to significantly lower plasma cortisol levels than did saline treatment. However, there were no significant differences in plasma AST and ALT between groups. These results support the positive osmoregulatory role of PRL in black porgy during FW adaptation.     

Enhancement of the catalytic activity of a 27 kDa subtilisin-like enzyme from Bacillus amyloliquefaciens CH51 by in vitro mutagenesis

AprE51 from Bacillus amyloliquefaciens CH51 is a 27 kDa subtilisin-like protease with fibrinolytic activity. To enhance the catalytic activity of AprE51, two residues, Gly-169 and Ser-101, which, according to the three-dimensional structural model of subtilisin, are located in the P1 substrate-binding site and S3 subsite, respectively, were mutated by site-directed mutagenesis. Results of the mutational analysis showed that substitution of alanine for Gly-169 increased the fibrinolytic activity 1.4-fold. All four Ser-101 mutations, that is, replacements with arginine, leucine, lysine, and tryptophan, also increased the fibrinolytic activity up to 3.9-fold. The S101W mutant with a bulky side chain was more active than mutants with a positively charged or nonpolar small side chains. The fibrinolytic activity of the S101W mutant was further increased by error-prone polymerase chain reaction. The AprE51-6 mutant (S101W/G169A/V192A) had stronger fibrinolytic activity than the S101W mutant. Purified AprE51-6 had a 2.5-fold higher k(cat) and a 2.3-fold lower K(m), which resulted in a 6-fold increase in catalytic efficiency (k(cat)/K(m)) relative to that of wild-type AprE51. In addition, AprE51-6 showed a relatively broader pH range and increased thermostability as compared to AprE51.     

Effects of corn dried distiller's grains with solubles and enzyme premix supplements on growth performance,carcass characteristics and meat quality parameters in finishing pigs

The objective of the present study was to investigate the effects of corn dried distiller's grains with solubles (DDGS) and enzyme premix (mannanase + phytase) supplementation on the growth performance, carcass and meat quality parameters in finishing pigs. Sixty hybrid pigs (L × LW × D) with initial weight of 63.92 ± 1.50 kg were used in a 3 × 2 factorial design with main effects of DDGS levels (0, 10 and 20%) and enzyme premix levels (0% vs. 0.14%). Average daily gain (ADG, P < 0.01) and average daily feed intake (ADFI, P < 0.05) were decreased due to an increased level of DDGS additive while the feed conversion ratio was improved (P < 0.05) by adding enzyme premix. The diet cost/gain (won/kg) was saved (P < 0.01) due to an increased level of DDGS additive. There were no significant differences in carcass characteristics and meat quality parameters of Longissimus dorsi muscle by DDGS level and enzyme premix. Palmitoleic acid, oleic acid and monounsaturated fatty acid (MUFA) decreased (P < 0.05) according to DDGS level. The results indicate that DDGS may be used in feeds for finishing pig as a replacement of corn and soybean meal without affecting their carcass characteristics and meat quality.     

Expression of KA1 kainate receptor subunit in the substantia gelatinosa of the trigeminal subnucleus caudalis in mice

The KA1 kainate receptor (KAR) subunit in the substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) has been implicated in the processing of nociceptive information from the orofacial region. This study compared the expression of the KA1 KAR subunit in the SG of the Vc in juvenile, prepubescent and adult mice. RT-PCR, Western blot and immunohistochemistry analyses were used to examine the expression level in SG area. The expression levels of the KA1 KAR subunit mRNA and protein were higher in juvenile mice than in prepubescent or adult mice. Quantitative data revealed that the KA1 KAR subunit mRNA and protein were expressed at levels approximately two and three times higher, respectively, in juvenile mice than in adult mice. A similar expression pattern of the KA1 KAR subunit was observed in an immunohistochemical study that showed higher expression in the juvenile (59%) than those of adult (35%) mice. These results show that the KA1 KAR subunits are expressed in the SG of the Vc in mice and that the expression level of the KA1 KAR subunit decreases gradually with postnatal development. These findings suggest that age-dependent KA1 KAR subunit expression can be a potential mechanism of age-dependent pain perception.     

Long-Term Inorganic Fertilization Effect on the Micronutrient Density in Soil and Rice Grain Cultivated in a South Korean Paddy Field

Soil fertility exerts a direct influence on the essential micronutrient contents of food crops. The focus in this study was on the role that long-term inorganic fertilization (nitrogen (N), phosphorous (P) and potassium (K)) plays in increasing the micronutrient output of the paddy cropping system. After more than 45 years of inorganic fertilizer application, the combined application of fertilizers (PK > NP > NK) substantially increased As (arsenic), B (boron), Cd (cadmium), Co (cobalt), Cr (chromium), Cu (copper), Fe (iron), Mn (manganese), Mo (molybdenum), Ni (nickel), Se (selenium), V (vanadium) and Zn (zinc) density in the soil and rice grain. Optimized and continuous application of PK fertilizers increased the overall micronutrient densities in rice milling fractions (grain and bran). Micronutrient concentrations were usually the highest in bran. Both grain and bran were rich in Fe, Mn and Zn. Correlation analysis indicated that soil pH and organic matter exert a significant and direct effect on the micronutrient concentration of rice. Although long-term fertilization enhanced the proportion of micronutrients in rice grain, the levels were still much lower than the recommended dietary intake levels for micronutrients. We therefore suggest high consumption levels of brown rice (with micronutrient-dense bran layer) because they may increase the daily intake level of micronutrients and meet the nutritional requirements that people need for sound health.     

Preparation of syndiotactic poly(vinyl alcohol) embolic particles with radiopacity

A suspension copolymerization in the presence of aqueous radiopaque nanoparticles was used to prepare poly(vinyl pivalate/vinyl acetate) (P(VPi/VAc)) nanocomposite microspheres for embolic materials. To generate nanocomposite microspheres with radiopacity, various radiopaque nanoparticles (TiO₂, Ti, Ag, Au and Pt) were added to P(VPi/VAc) copolymer. The P(VPi/VAc)/nanoparticles microspheres with radiopacity were then saponified in alkali solution, leading to syndiotactic poly(vinyl alcohol) (s-PVA)/nanoparticles microspheres with radiopacity of which degree of saponification (DS) was up to 99.8 %. The saponification time of P(VPi/VAc)/nanoparticles microspheres decreased with increasing the amount of nanoparticles. Computed tomography (CT) analysis revealed that s-PVA/TiO₂ and s-PVA/Ti microspheres had good radiopacity.     

Preparation of poly(vinyl alcohol)/silver-zeolite composite hydrogels by UV-irradiation

Poly(vinyl alcohol) (PVA)/Ag-zeolite nanocomposite hydrogels were prepared by UV irradiation using PVA solution mixed with Ag-zeolite nanoparticles. Physical properties and changes in morphology of the PVA/Ag-zeolite hydrogels were investigated. The PVA/Ag-zeolite hydrogels were prepared at a PVA concentration of 9 wt% with a UV irradiation distance of 15 cm, where gel fraction and swelling ratio were optimized. Hardness of the PVA/Ag-zeolite hydrogels decreased with increasing amounts of Ag-zeolite, reaching that of soft elastomer when the amount of Ag-zeolite was 5 % by weight. The PVA/Ag-zeolite hydrogels showed strong antimicrobial activities against Staphylococcus aureus and Klebsiella pneumoniae, inducing a reduction of bacteria of over 99.9 % at a Ag-zeolite content of 3 wt%.