[Natural soil genesis in red mud and underlying microbial mechanism.] / èµ¤æ³¥è‡ªç„¶æˆåœŸè¿‡ç¨‹åŠå ¶å¾®ç”Ÿç‰©é©±åŠ¨æœºåˆ¶.

Soil genesis is important for ecological restoration of red mud disposal area. Soil genesis of red mud and the microbial mechanism were studied by analyzing the change of physicochemical and biochemical characteristics of red mud. We analyzed the microbial community structure in a red mud disposal area without any human-induced restoration through a space for time substitution approach. The results showed that, with the increases of storage time, the physical parameters of porosity, water-stable aggregates content, and mean weight diameter increased, but the bulk density decreased. The chemical parameters, including pH, electrical conductivity, acid neutralizing capacity, and exchangeable sodium percentage, decreased with increasing storage time. The bio-chemical parameters of total organic carbon, total nitrogen, available phosphorus, microbial biomass carbon and basal respiration increased, but the metabolic quotient decreased. The Shannon diversity index increased, and the dominant microflora in red mud changed from the oxygenic photosynthetic bacteria Cyanobacteria and thanaerobic anoxygenic phototrophic bacteria Chlorobi and Chloroflexi to Proteobacteria, Actinobacteria and Firmicutes. The ratio between eutrophic and oligotrophic bacteria substantially increased. The micromorphology results showed that the microorga-nism-red mud aggregates were formed through adsorption, linkage, intertwinement and package between red mud particles, microbial cells and their metabolites. The red mud biotope changed spontaneously from extreme and oligotrophic into soil-like under natural stockpiling. The soil genesis process was mediated by microbes through increasing nutrient level, decreasing alkalinity and sali-nity, and improving soil structure.

[Effects of furadan on soil enzyme activity].

By using simulation method, this paper studied the effects of furadan on the activities of soil urease, invertase and alkaline phosphatase, with the affecting factors investigated. The results showed that after adding furadan into soil, soil urease activity was decreased first but increased then, indicating that the ecotoxicity of furadan was reduced gradually. When the concentration of furadan was less than 0.3%, soil urease, invertase and alkaline phosophatase were all activated, and in some soil samples, a significant positive correlation was observed between soil invertase activity and furadan concentration, suggesting that soil invertase activity could be used as an indicator for the soil pollution caused by furadan. It was concluded that the quality of soil and ecological environment would be kept safe under low concentrations of furadan (< or = 0.3%).

[Preparation and characterization of monoclonal antibodies against human laminin].

AIM: To prepare monoclonal antibody(mAb) against humen laminin(LN) and identify their properties. METHODS: BALB/c mice were immunized with humen LN, and then mAb was prepared by hybridoma technique. The titres of mAbs in ascetic fluid and relative affinity of mAb were determined by indirect ELISA test. Ig subgroup, specificity and combine dot of mAb were analysed by ELISA. RESULTS: 4 hybridoma cell lines 2A3, 2C6, 3G7 and 4H2 secreting anti-humen LN mAb were obtained. Their Ig subgroup belonged to IgG1, light chains were type kappa, The titres of 4 mAbs in ascitic fluid were 3.6 x 10(4)-2.1 x 10(6). Relative affinity of mAb 2C6 was above 10(12) and relative affinity of other 3 mAbs 2A3, 3G7 and 4H2 was 10(6), 10(8) and 10(8). Epitope recognized by 2 mAb(2A3 and 4H2) differed from the that by 2C6 and 3G7 another. CONCLUSION: 4 mAbs against humen LN has been prepared successfully and possess higher titer, specificity and relative affinity. Preparation of anti-human LN mAbs provide a useful reagent for further studying the role of LN in some diseases.