Polysaccharides from dandelion (Taraxacum mongolicum) leaves: Insights into innovative drying techniques on their structural characteristics and biological activities.

The aim of this study was to well understand the impacts of innovative drying techniques (radio frequency drying and microwave drying) and traditional drying techniques (vacuum drying, freezing drying, and hot air drying) on the structural characteristics and bioactivities of polysaccharides from dandelion leaves (DLPs). Five different DLPs were obtained from dandelion leaves dried by abovementioned drying techniques. Results showed that the structural characteristics and bioactivities of DLPs varied with different drying techniques. The molecular weights, apparent viscosities, molar ratios of constituent monosaccharide, contents of uronic acids, and contents of bonded polyphenolics in DLPs obtained by different drying techniques had noticeable variations, while the types of constituent monosaccharides and the major glycosidic linkages in DLPs were similar. In addition, results showed that DLPs, especially DLP-RF obtained by the radio frequency drying, exhibited remarkable antioxidant activities (ABTS, DPPH, and NO radical scavenging activities), excellent in vitro antiglycation activity, and obvious in vitro inhibitory activity on α-glucosidase. Results from this study suggest that the radio frequency drying can be used as a potential drying technique before extracting DLPs for applications in the functional food and medicine industries.

Description of three new species of Arescon Walker (Hymenoptera, Mymaridae) from China.

Three new species of Arescon Walker, 1846, Arescon gaoligongensis Jin & Li, sp. n., Arescon sparsiciliatus Jin & Li, sp. n. and Arescon stenopterus Jin & Li, sp. n. are described. A key to the Chinese species is given and photomicrographs are provided to illustrate morphological characters. All the specimens are deposited in the insect collections of Northeast Forestry University, China.

[Specific molecular markers of the rust resistance gene M4 in flax].

Flax (Linum usitatissimum L.) is an important fiber and oil-producing crop. Flax rust, caused by Melampsora lini Ehrenb. Lev., occurs worldwide and can cause severe losses in seed yield and fiber quality. In order to identify molecular markers linked to the flax rust resistant gene M4, RAPD analysis of NM4, a near-isogenic line containing the M4 gene, and the recurrent parent Bison was carried out with 540 decamer primers. The primer OPA18 could stably amplify a specific fragment, OPA18(432), in the NM4 line. The OPA18(432) marker was testified to be closely linked to the M4 gene with a genetic distance of 2.1 cM through the analysis of the F2 mapping population derived from a cross of Bison x NM4. Based on the sequence of OPA18(432), the specific PCR primers were designed, and a SCAR marker for the M4 gene was produced. Amplification of different resistant materials proved that the maker is specific for the M4 gene. This marker has been used successfully in marker-assisted selection in the flax breeding program.