In evolutionary terms, any organism that survives our concerted attempts at eradication goes on to found a stronger (more resistant) population, which requires that we invent an even more potent chemical to deal with the problem, and so the evolutionary arms race continues.
A drug that inhibits an individual oncogene, therefore, only targets a subset of the cancer's cells; in fact, as the cancer ecosystem is one where tumour cells are forever competing for resources, removing a sub-population of cancer cells can inadvertently facilitate the expansion of another, perhaps more resistant sub-population, a concept known as competitive release (Greaves and Maley, 2012).
Whilst GISA has a more "homogeneous" resistant population resulting in a higher, stable (thus more reproducible) vancomycin MIC, h-GISA expresses the resistance at approximately 1/106 of the native population thereby eluding detection by conventional methods.
Outcome measures included the LT50 (exposure time required to achieve 50% knockdown), the RR (resistance ratio, i.e. a calculation of how much more resistant the wild population is compared with a standard susceptible strain) and the mortality rate following 1 hour exposure, for each insecticide and each mosquito age group.
These data also demonstrate that culture of cells in a three-dimensional system alters their response to oxaliplatin, as revealed by comparing the outer cell response to that of control monolayers; this reveals that cells grown in three dimensions are inherently more resistant (B sub-population IC50, 13 μ M, control monolayer IC50, 2.4 μ M).
Despite the relatively low dose intensity of carboplatin and more platinum-resistant populations, both studies saw responses (11% and 13.8%), although in the study by Fu et al (2011), the majority of patients with platinum-resistant disease had received other therapy before study entry, and actual platinum-free intervals ranged from 6 to 31 months.
The ultramafic-associated microbial population (including bacteria and fungi) was dominated by bacteria and was more resistant to metals than populations from non-ultramafic soils.
Harris suggests that APOBEC3H could be the target of future gene therapy, aimed at making susceptible populations more resistant to the virus.
Finally we found that the fitness increase is not the product of selection during the course of the experiment, as exposure to 100 mM did not make the populations more resistant to EMS (Figure 6).
However, even though fisheries-induced evolution appeared to make populations more resistant to extinction, the flip side of adaptation was observed when the harvest pressure was removed.
