Due to the sensitivity of microarrays, plant-to-plant variation of gene expression could be reduced by bulk harvesting of resistant and susceptible hybrids.
Infected cells were selected with 0.5 µg/mL neomycin for 12 days and the bulk of the resistant cells was used in subsequent experiments.
Four bulks of P. sojae susceptible plants each carrying 7 8 F2:3 susceptible families and one bulk of P. sojae resistant plants containing two homozygous (PSS1PSS1) and six heterozygous (PSS1pss1) familiesilies were generated.
If the large BFR is caused by different allele frequencies at the DNA level in the two bulks but not by allele-specific expression, the ratio of the two alleles in the combined bulk (resistant bulk plus susceptible bulk) should be relatively small and predictable with the family structure.
As the bulk of antimicrobial resistance is mainly associated with the most genotypically diverse group in our dataset, it would be interesting in future investigations to determine if the antibiotic resistant DT104 has an elevated mutation rate.
Alternatively, the bulk of these SDS-resistant oligomers maybe made up of Kcv channels where TM1 spans the membrane with an 'inverted' topology, in which case the lack of N-linked glycans is consistent with the levels of N-glycosylated tetramer observed with full-length OPG-Kcv (cf. Figure 4E, lanes 4 and 8).
The increase in chemotherapy sensitivity by IGFBP7 might hold true for the bulk of the AML, however, also for small subpopulations of resistant leukemic cells.
In this scenario, an intriguing hypothesis is that secondary resistance is in fact nothing but the clonal selection of a minor subpopulation of cells that pre-exist before treatment and harbour a priori resistant alleles: drug exposure eliminates the bulk of sensitive cells, eventually leading to expansion of the resistant clones.
In another study, a higher prevalence of resistant E. coli was found in calves fed non-pasteurized waste milk compared to calves fed bulk tank milk, but no differences were found in the proportion of resistant Enterococci[ 7].
Many currently administered chemotherapies target the rapidly proliferating cells of the tumor bulk but fail to eradicate the intrinsically resistant CSCs, thus inadvertently leading to expansion of the CSC pool and/or selection of resistant CSCs.
