[Isolation and characterisation of Spiroplasma sp. from Phytomia zonata (Diptera: Syrphidae)]

To obtain the spiroplasma resources and characterize the spiroplasmas from insects in China, as well as study the taxonomy of spiroplasma based on biological characteristics.

We determined morphology by using dark field and transmission electron microscopy. The biological characteristics of the spiroplasmas were studied by using conventional culture-dependent method and phylogenetic analysis based on 16S rDNA.

Based on morphological characteristics, biological characteristics and phylogenetic evidences, we studied the taxonomy of the strain YY0801 isolated from Phytomia zonata (Diptera: Syrphidae). The isolate grew well in R2 liquid medium and could pass through 0.22 microm and 0.45 microm filtrate membranes. The colony was grain-like in solid medium. Through electron microscopy, the isolate YY0801 exhibited helicity during their exponential growth phase. The isolate YY0801 was able to ferment glucose and D-fructose and to catabolize arginine, but did not to hydrolyse urea. The isolate was resistant to ampicillin (2000 U/mL). The phylogenetic relationships based on 16S rDNA supported YY0801 grouped with the serogroup I and was close to S. melliferum.

The result indicated that the spiroplasma isolate YY0801 was close to S. melliferum, but further designation need support of serological analyses.