AOA have proven difficult to isolate in culture, as evidenced by the fact that only one pure culture [21] has been documented despite reports of several enrichment cultures [12], [22] [25].
Chronic schistosomiasis has been associated with the burden of anemia in these developing regions for many years, although it has proven difficult to isolate and substantiate the association owing to the number of confounding factors that exist within these regions [3], [4].
It has proven difficult to isolate mutants and devise assays that specifically address the mechanism (or mechanisms) of checkpoint silencing.
In the past, such targets have proven difficult to isolate because of the low solubility and low abundance of membrane proteins.
Despite the existence of well-defined cytotypes that have been proven to be reproductively isolated, questions remain regarding the taxonomic level of the closest cytotypes, such as Paraná and Carajás, or even Juína and Rondônia.
The Donaghy case, even if it proves to be isolated to one individual, has opened the door to much greater scrutiny of N.B.A. referees, and in particular the league's program for reviewing their performance.
Most suspect that Sunni extremists angry with Hezbollah's role in Syria carried out the recent bombing and a similar one five weeks earlier, though no one knows if these will prove to be isolated attacks or the start of a series.
S. pyogenes, one of the most prominent PTA pathogens, proved to be isolated from between 20 % and 30%% or approximately 45%% of PTAs [ 1, 7, 10, 12, 20].
Furthermore, it is noteworthy that insect symbionts such as S. glossinidius and members of the candidate genus Arsenophonus have proved difficult to isolate and manipulate in pure culture because they demonstrate a high level of sensitivity towards oxidative stress when cultures are maintained on agar plates at low cell densities [70].
Insulin, however, proved difficult to isolate.
Thus, it should prove possible to isolate contributions of these variables by applying the logic applied here to isolate changes in the sensitivity of the BSR substrate from other determinants of reward pursuit.
