Identification of Angelica sinensis and its adulterants based on ITS2 sequence / 中草药

Objective In this study, Angelica sinensis and its adulterants, close relatives were analyzed by ITS2 sequences to investigate the genetic structure from Min County, Gansu Province. Methods In this study, the internal transcribed spacer 2 (ITS2) regions of samples were amplified by PCR and sequenced bi-directionally. Obtained sequences were assembled using Codon Code Aligner. The genetic distances were computed by MEGA 6.0 in accordance with the kimura 2-parameter (K2P) model and the phylogenetic tree was constructed by Neighbor-joining (NJ) method. Moreover, the secondary structure of ITS2 was predicted using ITS2 database websites. Results The ITS2 region was 230 bp and base composition was GC content of 55.46% of A. sinensis in Min County. In its adulterants and close relatives of A. sinensis, the ITS2 region ranged in size from 228-233 bp and base composition was with G + C content ranged from 51.53%-65.65%. A total of 220 polymorphic sires were detected from 53 sequences, in which parsimony informative sires were up to 213. By K2P model, the intra-specific genetic distances of A. sinensis in Min County were smaller than inter-specific ones of A. sinensis and its adulterants in ITS2 regions. NJ tree and secondary structure results could distinctly differentiate quality product and adulterants. Conclusion ITS2 sequence can accurately identify the authenticity of A. sinensis, which provide a effective technology for the healthy and sustainable development in A. sinensis market.

Astragali Radix and Hedysari Radix molecular identification of SSR primers screening and fingerprints code / 中国中药杂志

Leguminous related SSR primers were collected, core primers used for Astragali Radix and Hedysari Radix identification were screened and validated by using molecular marker techniques. 6 core primers were selected from 101 pairs of primers, the molecular weight of PCR products was 100-500 bp, which formed 7-12 electrophoresis bands with 55 amplified loci. The percentage of polymorphic loci was 100%, and the average polymorphism information content was 0.371. According to the results of cluster analysis, obtained core primer could completely distinguish 62 mixture samples of Astragali Radix and Hedysari Radix in similarity coefficient of 0.46. Core primers and the corresponding characteristics from gel electrophoresis were tagged. The results provide identification basis for Astragali Radix and Hedysari Radix.

Isolation of Acidithiobacillus ferrooxidans by Using Solid-plate Magnetophoresis / 中国生物工程杂志

Acidithiobacillus ferrooxidans are able to synthesize intra-cellular electron-dense magnetite,which makes possible that the bio-nano-magnetic particles could be obtained by cultivating Acidithiobacillus ferrooxidans. In order to isolate the strain which has the capacity to produce more magnetic particles, the solid-plate magnetophoresis method was firstly created. After isolation using the method, the rate of the cells which contain intra-cellular magnetic particles was increased from 30% to more than 90%, in addition, after isolation each cell possessed 2~5 magnetic particles which disperse in cells. The isolated cells are able to orient and migrate to the magnet in artificial magnetic field but could not orient swimming only under the geomagnetic field. Magnetosomes produced by Acidithiobacillus ferrooxidans were range from 40nm to 90 nm according to the results of TEM. Energy dispersive X-ray analysis indicated that extracted magnetic particles consisted of oxygen and iron. The results show that some Acidithiobacillus ferrooxidans cells have weak magnetotaxis and they could be able to be separated by solid-plate magnetophoresis method from others. With the development of this new isolation method, it is possible to do deeper research to generate a comprehensive description of the mechanism that how Acidithiobacillus ferrooxidans synthesize the magnetic particles.

Research on Isolating Bacteria by Using Magnetophoresis / 中国生物工程杂志

There are similarities between magnetotactic bacteria and Acidithiobacillus ferrooxidans (A. ferrooxidans) which isolated from Acid mine drainage(AMD). The weak magnetotaxis of some bioleaching bacteria isolated were found by microscope. A magnetophoresis apparatus was designed based on these weak magnetotaxis and be used to analysis the movement of these strains. The physiological properties of the anear magnetic field strain and removed magnetic field strain which isolated successfully by magnetophoresis apparatus have large difference. The nanometer magnetic particles was extract from the Acidithiobacillus ferrooxidans which purified by spread plate method from AMFS and its main elements are Fe and O by energy spectrum analysis. The results show that A. ferrooxidans have weak magnetotaxis and can be isolated by magnetophoresis. With the development of this new isolating method, the research of magnetotactic bacteria and bioleaching will get more benefit from it.