p38a13, p38b156A double mutant flies exhibit abnormal heart function, as characterised by an increased incidence of irregular beats, a broader distribution of HPs, and significantly elevated the arrhythmia index, compared to wild-type flies. The diastolic and systolic diameters are significantly smaller in p38a13, p38b156A double homozygotes than in wild-type, resulting in a narrower heart tube.
A p38b156A, p38a13 double mutant background partially restores a normal heart rhythm and normalizes the diastolic and systolic heart diameters of flies expressing CatScer\UAS.cAa under the control of Scer\GAL4Dot.PK.
Mpk213 p38b156A double mutant flies show a reduced survival rate compared to control flies after infection with either P. aeruginosa, S. aureus or A. fumigatus. The mutant flies show normal resistance to infection with E. coli.
Mpk213 p38b156A double mutant animals typically die at larval and pupal stages under standard culture conditions, with only a few escapers. Raising the double mutant animals under either near-sterile conditions or with standard food containing antibiotics results in a significant increase in survival rate to the pupal stage.
Mpk213 p38b156A double mutant animals show reduced survival to the pupal stage compared to controls when raised on sterilised food into which P. aeruginosa has been introduced. Introducing E. coli or S. cerevisiae into sterilised food has no effect on survival of Mpk213 p38b156A double mutants.
Double mutant Mpk213 p38b156A larvae show melanisation in the hindgut. There is a significant reduction in this melanisation if the animals are cultured in near-sterile conditions ot on standard food containing antibiotics. Introduction of P. aeruginosa into sterilised food increases the occurrence of melanisation in the Mpk213 p38b156A animals, while introduction of either E. coli or S. cerevisiae has no effect on melanisation in the hindgut.