ABSTRACT
Phenol oxidase plays an important role in the degradation of soil organic matter. There was no standard method to determine soil phenol oxidase activity. To fill such knowledge gap, we investigated the effects of substrate type, pH, soil storage conditions, storage time, substrate concentration, water-soil ratio, incubation time and incubation temperature on soil phenol oxidase activity in three different subtropical forest soils developed on sandstone. The pH of extraction buffers significantly affected the phenol oxidase activity. Using 2,2'-azinobis-(-3-ethylbenzo-thiazoline-6-sulfononic acid)-diammonium salt (ABTS) as substrate acquired higher oxidase activity and was applicable to wider pH range than using 3-(3,4-Dihydroxyphenyl)-L-alanine (L-DOPA) as substrate, indicating that ABTS was more suitable as a substrate for measuring phenol oxidase activity in acidic soils of subtropical forests. The storage condition significantly affected phenol oxidase activity. The phenol oxidase activity declined with time in all the three types of soil. The decreasing rate was air-dried > 4 â refrigerated > -20 â frozen > -80 â frozen, suggesting that the frozen storage method was better than others in maintaining soil phenol oxidase activity if the determination of phenol oxidase activity in fresh soil samples cannot be immediately done. Substrate concentration, water-soil ratio, and incubation time and temperature all affected the activity of soil phenol oxidase. The condition of soil: buffer ratio of 1:100, 2 mmol·L-1 concentration of ABTS with an incubation time of 4 h at 25-30 â was optimal for measuring phenol oxidase activity in acidic soils of subtropical forests, with high repeatability and sensitivity.
Subject(s)
Monophenol Monooxygenase , Soil , China , Forests , Soil Microbiology , WaterABSTRACT
With the aim to understand the influence degree and mechanism of parent material and forest type on soil phosphorus component, we analyzed soil P fractions, iron and aluminum oxides, microbial biomass, and phosphatase activity in Castanopsis carlesii and Cunninghamia lanceolata forest soils developed from two types of parent materials, sandstone and granite, in Sanming, Fujian Province. The results showed that both parent material and forest type significantly affected the contents of different P fractions. The contents of total P, labile inorganic/organic P, moderately labile inorganic/organic P, and non-labile P from sandstone-developed soils were significantly higher than those from granite-developed soils. Moreover, soil labile organic P, moderately labile inorganic/organic P and non-labile P fraction in sandstone-developed soils of C. carlesii forest were significantly higher than those of C. lanceolata forest, while the corresponding soil P fractions in granite-deve-loped soils had no significant difference between the two types of forests. The activity of acid phosphatase (ACP) in granite-developed soils was significantly higher than that in sandstone-developed soils under two types of forest, while soil microbial biomass carbon (MBC) and P (MBP) in sandstone-developed soils were significantly higher under C. carlesii forest than under C. lanceolata fo-rest. The content of soil P fractions was significantly positively correlated with the content of different forms of iron and aluminum oxides, MBP, and MBC, but negatively correlated with soil pH and acid phosphatase activity (ACP). Our results indicated that parent material and forest types might affect soil P fractions and characteristics mainly through altering soil iron and aluminum oxides, ACP, MBP in mid-subtropical forest soils.
Subject(s)
Phosphorus , Soil , Carbon/analysis , China , Forests , Nitrogen/analysis , Phosphorus/analysisABSTRACT
<p><b>OBJECTIVE</b>To analyze irrational clinical application of Houttuynia Injection (HI) and the risk of adverse event (AE) occurrence, thus providing references for after-sales reevaluation and rational clinical application of HI.</p><p><b>METHODS</b>Literatures concerning unreasonable application of HI were searched (terminated by June 2010) from PubMed, EMBASE, Chinese Biomedical Disc (CBMdisc), Chinese National Knowledge Infrastructure (CNKI), Chinese Science and Technology Journal Full-text Database (VIP), and etc. for case report, cross-sectional study, and clinical control study.</p><p><b>RESULTS</b>A total of 342 papers with a total of 416 AE cases were retrieved. Of them, AE happened to 294 cases (including 290 children) of the 132 papers concerning contraindications, and 48 with allergic shock; AE happened to 57 cases in 9 papers reporting over-dose, and 6 with high risk combined medication. Sixteen irrational administration ways were reported in 195 papers. Of them, AE happened to 59 cases of seven administration ways (twenty cases by intracavitary injection, thirteen by aerosol inhalation, ten by rinse, eight by oral administration, one by enema, one by acupoint injection, and one by rectal administering). AE was not reported in the rest ten reports.</p><p><b>CONCLUSION</b>The risk of AE occurrence was increased by changing clinical administration ways of HI without authorization, over-dose medication, high risk combined medication, and application in people with contraindications.</p>
