Mode of action and active site of an extracellular peroxidase from Pleurotus ostreatus

Effect of dietary pyrroloquinoline quinone disodium in sows on intestinal health of the offspring

The objective of this study was to investigate the effects of dietary pyrroloquinoline quinone disodium (PQQ·Na2) supplementation in sows during gestation and lactation on intestinal health in offspring. A total of 40 cross-bred (landrace × large white crossed with Duroc boar) multiparity gestation sows with an average parity of 4.3 were used in this study. Forty sows were allotted to 2 dietary treatments after breeding. One group was the control sows, which were fed a corn-soybean meal control diet (Con treatment, n = 20), and the other group was the treatment sows fed a control diet with 20 mg kg-1 PQQ·Na2 after breeding and through gestation and lactation (PQQ treatment, n = 20). The activities of SOD and GSH-Px were significantly (P < 0.05) increased by PQQ·Na2 supplementation, and MDA activity was decreased (P < 0.05) in the plasma of piglets. CAT, SOD and GSH-Px activities were significantly (P < 0.05) increased, and MDA activity was decreased (P < 0.05) in the small intestine of piglets. The mRNA expression levels of SOD1, CAT and MGST1 in the jejunum were increased in newborn piglets (P < 0.05), and the mRNA expression levels of HO1, SOD1, CAT, SOD2, GPX4, GPX1 and GCLC in the jejunum were increased in weaned piglets (P < 0.05). The mRNA expression of ZO-1 was increased (P < 0.05) in the jejunum of newborn piglets, and the mRNA expression of Occludin and ZO-1 was increased (P < 0.05) in the jejunum of weaned piglets. The villous height of the duodenum and jejunum of weaned piglets was increased (P < 0.05) by dietary PQQ·Na2. In weaned piglets, Bacteroidetes and Firmicutes were the most prevalent phyla in both the Con and PQQ·Na2 treatment groups, and the most prevalent genera were Alloprevotella and Bacteroides. At the phylum level, the abundance of Firmicutes was significantly increased (P < 0.05), and the abundance of Proteobacteria was significantly decreased (P < 0.05). At the genus level, the abundance of Alloprevotella was significantly increased (P < 0.05), and the abundance of Actinobacillus and Escherichia was decreased (P < 0.05). In conclusion, dietary supplementation with PQQ·Na2 in sows during gestation and lactation had positive effects on intestinal health in offspring.

Microbial decolorization of melanoidin-containing wastewaters: Combined use of activated sludge and the fungus Coriolus hirsutus

A white rot fungus, Coriolus hirsutus, exhibited a strong ability to decolorize melanoidin in cultures not supplemented with nitrogenous nutrients. Addition of peptone to the cultures lowered the ability of the fungus to decolorize melanoidin, but that of inorganic nitrogens (Ns), ammonium and nitrate did not bring about any marked reduction in the ability. These results suggest an inhibitory effect of organic N on melanoidin decolorization. Therefore, for enhancing the decolorization of melanoidin in wastewaters by the fungus, activated sludge pretreatment of the wastewaters was expected to be effective, i.e., activated sludge is capable of converting available organic N into inorganic N. To confirm this, waste sludge heat treatment liquor (HTL), wastewater from a sewage treatment plant, was pretreated with activated sludge. In practice, pretreatment of HTL under appropriate conditions accelerated the fungal decolorization of HTL. In the pretreated HTL, the fungus was shown to produce a high level of manganese-independent peroxidase (MIP). Addition of Mn(II) to the pretreated HTL caused a further increase in the decolorization efficiency of the fungus and a marked increase in the manganese peroxidase (MnP) activity. Consequently, the increases in MIP and MnP activities were considered to play an important role in the enhanced ability of C. hirsutus to decolorize HTL.

Production and Purification of Remazol Brilliant Blue R Decolorizing Peroxidase from the Culture Filtrate of Pleurotus ostreatus

An extracellular H(inf2)O(inf2)-requiring Remazol brilliant blue R (RBBR) decolorizing enzymatic activity was found in the culture medium of Pleurotus ostreatus. The enzymatic activity was maximally obtained in idiophase, and the optimum C/N ratio was 24. High C/N ratios repressed the enzymatic activity, and addition of veratryl alcohol had no effect on the production of enzyme. The enzyme was purified by ammonium sulfate fractionation, Sephacryl S-200 HR chromatography, DEAE Sepharose CL-6B chromatography, and Mono Q chromatography. The purification of RBBR decolorizing peroxidase, as judged by the final specific activity of 6.00 U/mg, was 54.5-fold, with a yield of 9.9%. The molecular mass of the native enzyme determined by gel permeation chromatography was found to be about 73 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the enzyme was a monomer with a molecular mass of 71 kDa. The enzyme was optimally active at pH 3.0 to 3.5 and at 25(deg)C. Under standard assay conditions, the apparent K(infm) values of the enzyme toward RBBR and H(inf2)O(inf2) were 10.99 and 32.97 (mu)M, respectively. The enzyme had affinity toward various phenolic compounds and artificial dyes, and it was inhibited by Na(inf2)S(inf2)O(inf5), potassium cyanide, NaN(inf3), and cysteine. The absorption spectrum of the enzyme exhibited maxima at 407, 510, and 640 nm. The addition of H(inf2)O(inf2) to the enzyme resulted in an absorbance decrease at 407 and 510 nm.