Community Structures of Arbuscular Mycorrhizal Fungi in Soils and Plant Roots Inhabiting Abandoned Mines of Korea

In this study, we collected rhizosphere soils and root samples from a post-mining area and a natural forest area in Jecheon, Korea. We extracted spores of arbuscular mycorrhizal fungi (AMF) from rhizospheres, and then examined the sequences of 18S rDNA genes of the AMF from the collected roots of plants. We compared the AMF communities in the post-mining area and the natural forest area by sequence analysis of the AMF spores from soils and of the AMF clones from roots. Consequently, we confirmed that the structure of AMF communities varied between the post-mining area and the natural forest area and showed significant relationship with heavy metal contents in soils. These results suggest that heavy metal contamination by mining activity significantly affects the AMF community structure.

Identification of Eucommia ulmoides and its adulterants based on ITS2 sequences / 中草药

Objective: To identify Eucommia ulmoides and its adulterants using ITS2 barcode, to discuss the feasibility of this new method, and to provide the technical support for the prevention against the confusion of commercial medicinal materials. Methods: DNA was extracted from each sample as template, the ITS2 region was amplified by PCR technology and sequenced bidirectionally using DNA cloning sequencing method. The sequence assembly and consensus sequence generation were performed using the Seqman program. Phylogenetic study was performed by MEGA 4.1, and the Nighbor-joining (NJ) dendrogram was constructed. The ITS2 secondary structure was predicted using the ITS2 website. Results: The maximum Kimura-2-parameter (K2P) genetic distance of E. ulmoides was far lower than the minimum K2P genetic distance of the adulterants. In the cluster dendrogram, E. ulmoides samples from various sources showed the monophyletic and simultaneously distinguished from the adulterants. To compare the ITS2 secondary structure, it could be noticed that ITS2 secondary structure could distinguish E. ulmoides from its adulterants in terms of numbers, sizes, positions of loop, and the angles of helix exsertion in four helix regions. Conclusion: ITS2 barcode could be used to distinguish E. ulmoides from its adulterants effectively, and provide the important molecular evidence for the identification of germplasm rescouces and clinic safety in medicinal use.

Localization of zearalenone detoxification gene(s) in pZEA-1 plasmid of Pseudomonas putida sp. strain ZEA-1 and expressed in Escherichia coli

The gene(s) encoding enzyme(s) involved in the initial reaction during degradation of zearalenone was characterized from the zearalenone utilizer Pseudomonas putida strain ZEA-1, in which ZEA transformed into product with less or not toxic. A 5.5 kilobase-pair (kpb) Pst1-Kpn1 fragment containing gene(s) coding for zearalenone degradation was cloned. The cloned gene(s) activity was expressed in Escherichia coli, and ZEA degradation by recombinant E. coli was relatively rapid and effective, leaving no detectable ZEA after 72 h. In further experiments, cell-free extract of E.coli have been used in the same way, both to confirm these observations and the enzymatic nature of the degradation activity.