Xue Changhu

Degradation of Extraction from Seaweed and Its Complex with Rare Earths for Organophosphorous Pesticides

Abstract On the basis of several experiments carried out in China, it was proved that both seaweed liquid fertilizer and rare earth (RE) could promote the growth of crops and increase their yield. The effects of extraction from seaweed and its complex with RE on the degradation of organophosphorous pesticides and the yield of vegetables were investigated. The results showed that the extract and its complex with RE could degrade organophosphorous pesticides in neutral solvent. The residues of the pesticides treated by the extract decreased by 96.88%, 52.30%, 49.52%, and 22.88%, respectively, for chlorpyrifos, dichlorvos, omethoate, and dimethoate, and those by the complex decreased by 95.99%, 54.23%, 48.79%, and 25.66%, respectively, when compared with the control. The residues of chlorpyrifos and dimethoate in spinach sprayed with the complex were decreased by 90.64% and 76.56%, respectively, compared with those in spinach from control plots when the interval between spraying and sampling was 8 d. The fresh weight of brassica chinensis and cabbage increased by 28.62% and 18.72%, and their dry weight increased by 44.49% and 14.74%, respectively, compared with those of the controls. The chlorpyrifos and dimethoate residues in brasscia chinese were decreased by 36.36% and 50.00%, respectively, and their rate of decrease in cabbage was 40.00% and 75.00%, respectively, on 5th day after spraying with the complex, when compared with those in the vegetable from control. These results suggest that this complex can increase the agricultural productivity and reduce the use of pesticide residues in the production of vegetables.

Changes in the contents of ATP and its related breakdown compounds in various tissues of oyster during frozen storage

The changes in the contents of adenosine 5’-triphosphate (ATP) and its related breakdown compounds were investigated in the adductor muscle, mantle, gill and body trunk of oyster (Crassostrea gigas) during frozen storage at −20°C and −30°C and compared with that of the fresh oyster. The investigation was performed using an HPLC system. Different extents of ATP decomposition were found in various tissues frozen at the two temperatures. The K, K’ and A.E.C values were calculated as the chemical freshness indices. Considering the results of sensory evaluation, the A.E.C. value in body trunk at −20°C and −30°C could be used as the best freshness index for frozen oyster.

Purification and characterization of an alkaline protease from Acetes chinensis

An alkaline protease from Acetes chinensis was purified and characterized in this study. The steps of purification include ammonium sulfate precipitation, ion-exchange chromatography with Q-sepharose Fast Flow, gel filtration chromatography with S300 and the second ion-exchange chromatography with Q-sepharose Fast Flow. The protease was isolated and purified, which was present and active on protein substrates (azocasein and casein). The specific protease activity was 17.15 folds and the recovery was 4.67. The molecular weight of the protease was estimated at 23.2 kD by SDS-PAGE. With azocasein as the susbstrate, the optimal temperature was 55°C and the optimal pH value was 5.5. Ion Ca2+ could enhance the proteolytic activity of the protease, while Cu2+, EDTA and PMSF could inhibit its activity.

Study on the tripolyphosphatase (TPPase) property of bighead carp (Aristichthys nobilis) myosin subfragment-1

Myosin subfragment-1 was prepared from the myofibrils of bighead carp (Aristichthys nobilis). The myosin subfragment-1 was proved to have the activity of tripolyphosphatase (TPPase) responding to the hydrolysis of sodium tripolyphosphate (STPP). The optimum temperature and pH for the TPPase of myosin subfragment-1 were 30°C and pH 5.0, and at pH 8.0 the TPPase also showed a high activity. Mg2+ was necessary to TPPase. The TPPase activity of myosin subfragment-1 was activated by Mg2+ under low concentrations, but was inhibited when the concentration was over 17 mmolL−1. The TPPase activity was also affected by KCl. The optimum concentration of KCl for TPPase was 0.3 molL−1 under the condition of 17 mmolL−1 Mg2+. The TPPase activity was significantly inhibited by EDTA-Na2. Reagents such as KBr, KI and KIO3 could inhibit the TPPase effectively. K2Cr2O7 as well as KMnO7 and KNO3 exhibited weak inhibiting effects. The TPPase converted STPP to pyrophosphate (PP) and orthophosphate (Pi) stoichiometrically with a KM of 3.2mmolL−1.

The hydrolyzation of collagen by fucoidan oligosaccharide’s complex with CeIV

Fucoidan is such a polysaccharide that its hydroxies are easy to combine with lanthanons ion (CeIV) to form complex. This work obtained the complexes of three fucoidan oligosaccharides with different molecular weights F1 (>5000), F2 (1000–5000) and F3 (<1000) by hydrolyzing Oligosaccharide collagen with sulfuric acid. It is found that the fucoidan oligosaccharide F3 can form complex with more CeIV than F1 and F2. Hydrolyzing collagen with the complex was carried out to produce amino acid and peptides. All the three fucoidan oligosaccharide complexes with CeIV (F1, F2, F3) can catalyze by the artificial hydrolytic enzyme, and the activity of the complex of F3 is the highest.

Hydrolysis Activities of the Particle of Agarose-Ce~(4+) Complex for Compounds Containing Phosphodiester or Peptide Bonds

Hydrolysis activities of PACC (particle of agarose-Ce4+ complex, newly made through double emulsification) for compounds containing phosphodiester or peptide bonds were studied. The results showed that PACC could hydrolyze organophosphorous pesticides not only in water but also in vegetable juice or tea extract. Hydrolysis rates of methamidophos, omethoate and chlorpyrifos in water are 32.39%, 27.12% and 46.62% respectively, those of chlorpyrifos and methamidophos in mung sprout juice 38.28% and 35.45% respectively, and that of chlorpyrifos in tea extract 59.76%. Hydrolysis rates of BSA (bovine serum albumin) in water and protein in tea extract by PACC increase by 54.30% and 86.46% respectively as compared with the control.