Confidence intervals (CI) were calculated using the formula: 95% CI = M ± (SE * 1.96) where M = Mean, SE = Standard Error. Genome sequencing For the template-dependent genome comparison study, 50 cells or a single cell from the yogurt P3 gate were sorted into
one PCR well each containing 2 μl lysis buffer, MDA-, and PCR-amplified, as described . Blastn of the 16S rDNA PCR products from both the single cell and 50-cell templates showed >98% identity to L. acidophilus (NCFM). To compare genome coverage, the single- and 50-cell amplicons were sequenced using the Illumina MiSeq platform using standard Illumina libraries made using the TruSeq DNA Library prep kit. Sequencing data was normalized using equal numbers of reads from each sample followed by quality screening and trimming consisting of removal selleck kinase inhibitor of ambiguous bases, ends trimmed with quality less than 10 and reads removed with average base-quality less than 20. Sequencing was performed using paired-end and non-paired end run see more resulting in ~151 bp reads with ~99% of the total reads being included after trimming. Reads were mapped to the L. acidophilus (NCFM)
selleck reference using the CLC Genomics Workbench (CLC bio). 83.9% and 88.2% of the single-cell and 50-cell (respectively) reads were mapped to the reference resulting in 68.6% and 99.9% coverage of the reference genome. The single-cell or 50-cell data resulted in 516 or 12 gaps with gap lengths ranging from 1 to 26,493 bps for the single
cell and 3 to 862 bp for the 50-cell data. For de novo assembly, prior to contaminant removal the sequencing data from the 50 cell template assembled into 2,931 contigs with N50 equal to 5,811 bp and minimum contig length of 177 bp with the longest contig being 157,137 bp long. The single cell sequence data assembled into 595 contigs with N50 equal to 7,100 bp with the minimum contig length equal to 200 bp and the longest contig being 62,621 bp. After removal of contaminants, de novo assembly using CLC resulting in 555 contigs (from the single cell assembly) or 124 (from the 50 cell assembly) and were mapped not back to the reference to assess coverage. Figures were generated using R as described above. Western blot and antigen identification by mass spectrometry Bacteria (1010) were lysed by resuspending the cells in a SDS-PAGE lysis buffer containing 2% SDS and 0.6 M β-mercaptoethanol and boiling at 98°C for 15 minutes. The lysed sample was run on a 4-12% SDS-PAGE gel and the separated protein was subsequently transferred to nitrocellulose membrane for Western Blot. The membrane was blocked in Casein blocking solution (Thermo Scientific) followed by incubation with 0.5 ug/ml recombinant α-La scFv in PBS for 1–2 hrs at RT. Following incubation with α-La scFv, the membrane was washed 1× with PBST followed by two washes with PBS, then incubated with 1:1000 dilution of anti-SV5 IgG conjugated to Alkaline Phosphatase (AP).