Studies On The Taxonomy Of Species In Dictyosteliaceae From Partial Areas Of Shanxi-Gansu-Ningxia And Volatile Constituents Of The Representative Species

Dictyostelids cellular slime molds are an unusual group which exist extensively in the soil,litter and animal dungs.It is a kind of organisms that feed on bacteria.This form of smaller biological can not be observed by naked eyes easily,which are difficult to be collected,and most of them are isolated in the laboratory culture.Because of its unique appearance characteristics and simple life cycle process,it is one of the ideal experimental materials for genetics,cytology and phylogenetic research.Dictyostelids contains some chemical composition with pharmacological activity.Dictyostelids are very promising raw medicine resources for studying and utilizing.In this study,15 species of 2 genera were isolated and identified from the soil or deciduous plants collected from some areas of Shanxi-Gansu-Ningxia,including 11 species of Dictyostelium,4 species of Polysphondylium New record species in Gansu contain D.gregarium?D.purpureum?P.candidum.New record species in Ningxia contain D.mucoroides?D.clavatum?D.macrocephalum?D.sphaerocephalum?D.aureostipes?D.giganteum?Dictyostelium multistipes?D.minutum.New record species in Shanxi contain P.tenuissimum P.violaceum.As is known species contain D.longosporum?P.pallidum.These substrates and obtained strains were stored in Jilin Agricultural University Mycological Herbarium.Several of them were tentatively examined by scanning electron microscopy and transmission electron microscopy.Scanning electron microscopy observed four dictyostelids.The result showed that the surface of the spores was not decorated,and the wall of the spores were thin and brittle,and the spores were shrivelled after drying.Through transmission electron microscopy can see the interior structure of the spores,including the nucleus,mitochondria,polar particles.Besides we can see the Escherichia coli which were preyed by the myxamoeba of Dictyostelium fasciculatum.The phylogenetic tree based on ITS was constructed by extracting the DNA of some parts of dictyostelid cellular slime molds and downloading the sequence from genbank.All species of dictyostelid cellular slime molds are divided into four groups.Selected the isolated strain D.fasciculatum and P.violaceum that is easier to collect as the material.They were enriched and analyzed by GC / MS for its volatile components.The result indicated that most volatile components of Polysphondylium violaceum are straight-chain alkanes.There were ten straight-chain alkanes in the twelve components and the total relative content was 13.49%.The other two were docosylsulfate and geranyl acetone.Geranyl acetone can be used as a pharmaceutical intermediates for the synthesis of vitamins.Most volatile components of D.fasciculatum are straight-chain alkanes,too.There were sixteen straight-chain alkanes in the twenty-two components and the total relative content was 23.56%.The relative content of the highest alkane is hexadecane,4.34%.Three of them were aldehydes,namely,nonylaldehyde,decanal and undecanal,and the relative contents were 2.25%,5.88% and 0.6%.In addition,there are phenol,indole and methyl heptenone in the volatile components of Dictyostelium fasciculatum.Methylergenone has aroma like lemon grass and isobutyl acetate.It is an important intermediate for the synthesis of pharmaceuticals,flavors and fragrances.