8% agarose gel and transferred without prior denaturation to a nylon membrane (Nytran SuPerCharge) by vacuum blotting in 10X SSC buffer (Vacuum Blotter; MP Biomedicals). The air-dried membrane was then UV cross-linked before hybridization with the pMyBK1 [digoxigenin]dUTP-labelled probe using standard stringency conditions. Hybridization signals were detected with anti-digoxigenin-alkaline phosphatase conjugate and CDP-Star as the substrate, according to the manufacturer’s see more instructions (Roche Applied Science). The pMyBK1 probe was generated by PCR amplification with primer pair pMyBK1-F1/R2 (Additional file 1: Table S1). For protein immunobloting, 107–108 c.f.u. from M. yeatsii and M. capricolum

subsp. Cytoskeletal Signaling inhibitor capricolum (Mcc) late-exponential-phase cultures were spotted under vacuum onto a nitrocellulose membrane. Immunoblotting was carried buy Thiazovivin out as described previously [41] except that the binding of spiralin-antibodies was visualized by using a goat anti-rabbit immunoglobulin G–peroxidase conjugate and the Super Signal West Pico chemoluminescent substrate (Pierce). Plasmid constructs and transformation experiments Several derivatives of pMyBK1 (pCM-H, pCM-P, pCM-C, pCM-K1-5) were constructed by inserting BglII-digested amplification products from pMyBK1 (BglII site in the primer sequences) into BglII-linearized pSRT2 [42]. Primers used

for amplification of fragments from pMyBK1 are listed in Additional file 1: Table S1. In each construct (see Results section and Figure 2), the CDSs of pMyBK1 else were kept in the same orientation as that of the pSRT2 tetM gene. To produce pCM-K3-spi, the spiralin gene and its promoter were amplified from S. citri GII3 genomic DNA with primer pair SpiERI-F/R, prior to restriction with EcoRI and ligation into EcoRI-linearized pCM-K3. In pCM-K1ΔB, the CDSB of pCM-K1 was disrupted by a 4-bp insertion creating

a unique XhoI site. To introduce the 4-bp frameshift mutation, the amplification product of pCM-K1 using DeltacdsB-F/DeltacdsB-R primers was restricted by XhoI before circularization by self-ligation. Figure 2 Structural organization and replication ability of pMyBK1 and derivatives. A. Plasmid constructs are described in Methods. Putative promoter and terminator of CDSA and CDSB are indicated for pMyBK1 only. Direct repeats (□) , inverted repeats (▸◂) and the GC-rich region (|||||) are indicated only for the pCM-C derivative. B, BglII; E, EcoRI; spi, Spiroplasma citri spiralin gene; tetM, tetracycline resistance gene from transposon Tn916, pBS, plasmid pBluescript. The signs on the right indicate the ability (+) and inability (−) to replicate in Mycoplasma yeatsii type strain GIH TS. * indicates a frameshift mutation in the cdsB sequence of pCM-K1ΔB. B. The replication ability of 4 pMyBK1 derivatives was evaluated in mollicute species belonging to the Spiroplasma phylogenetic group and shown to be initially plasmid-free: M. yeatsii #13156, M. putrefaciens KS1 TS, M.