All unialgal Bryopsis cultures were maintained in the laboratory at 23°C under a 12 h:12 h light/dark cycle with light intensities of 25-30

μE m-2s-1. One year after the first endophytic community screening [3], all five Bryopsis MX samples were resubmitted to a total surface sterilization [15] and DNA extraction [16] in October 2010 to evaluate the temporal stability of the Doramapimod research buy endophytic bacterial communities after prolonged cultivation. To address the specificity of the Bryopsis-bacterial endobiosis in culture, 50 ml of 30 day old cultivation water was collected from each Bryopsis MX culture that had been cultivated for two years (i.e. in February 2011). These cultivation water samples were serially filtered over a syringe filter holder with sterile 11 μm and 0.2 μm cellulose acetate filters (Sartorius Stedim selleck compound Biotech GmbH, Germany) to remove small Bryopsis fragments and to retain the planktonic microbial fraction, respectively. Bacterial DNA was extracted from the 0.2 μm filters using the bead-beating method followed by phenol extraction and ethanol

precipitation as described by Zwart et al. [17]. Parallel with these cultivation water samples, Ilomastat cost washing water samples were obtained from all five MX isolates by repeatedly vortexing the algae in 50 ml sterile artificial seawater (ASW). These washing water samples, containing the loosely Bryopsis-associated bacterial fraction, were processed as described above. Subsequently, approximately 1 gram of each washed Bryopsis MX sample was placed in 500 μl cetyltrimethylammonium

bromide (CTAB) lysis buffer supplemented with 20 mg.mL-1 proteinase K and 2.5 μl filter-sterilized Umonium Master (Huckert’s International, Belgium) to eliminate the epiphytic bacterial fraction from the Bryopsis surface [15]. Samples were incubated for 30 minutes at 60°C and subsequently vortexed 17-DMAG (Alvespimycin) HCl in 500 μl sterile ASW for 2 minutes. Algal material was removed by centrifugation and the supernatants’ DNA originated from the epiphytic bacterial fraction was extracted using a CTAB protocol modified from Doyle and Doyle [16]. DGGE and sequence analysis The endophytic (EN-2010), epiphytic (EP), washing water (WW) and cultivation water (CW) bacterial community extracts were subjected to a nested-PCR DGGE approach. First, full length 16S rRNA gene amplification was carried out with the universal bacterial primers 27F/1492R following the protocol outlined in Lane [18]. PCR amplicons were purified using a Nucleofast 96 PCR clean up membrane system (Machery-Nagel, Germany) according to the manufacturer’s instructions and subsequently submitted to a second PCR with primer pair F357-GC/R518 targeting the V3 region of the 16S rRNA gene. The latter amplification reaction and subsequent DGGE analysis were carried out as previously described [15], with a denaturing gradient of 45-65%.