Increase of PO activity in absence of PPO2.

<p>(<b>A</b>) Hemolymph PO activity in unchallenged and wounded adult flies. Spontaneous PO activity is abolished in <i>PPO1</i>^Δ, <i>PPO2</i>^Δ double mutant flies <i>(***, p</i><0.0005) and strongly reduced in <i>PPO1</i>^Δ mutants <i>(**, p</i><0.005) compared to wild-type. In <i>PPO2</i>^Δ deficient flies, a stronger PO activity is observed even in the absence of wounding <i>(*, p</i><0.05). Adult flies were punctured and 3 h later their hemolymph was examined for PO activity. Hemolymph of wounded <i>Bc</i> flies and unchallenged <i>Spn27A¹</i> flies was used as control. Data were analyzed by t test and values represent the mean±s.e. of three independent experiments. (<b>B</b>) A representative Western Blot analysis using <i>Drosophila</i> anti-PPO1 (top) and anti-PPO2 (bottom) antibodies. Hemolymph samples were collected from adult flies subjected to injury contaminated with a mixture of Gram-positive <i>Micrococcus luteus</i> and Gram-negative <i>Erwinia carotovora carotovora 15</i> (<i>E. carotovora</i>) bacteria. Absence of PPO1 and PPO2 in the respective single and double mutant flies is confirmed. Of note, higher levels of the mature form of PPO1 were observed in <i>PPO2</i>^Δ mutants consistent with the notion that PPO2 negatively impacts PPO1. Hemolymph was extracted from flies 3 h post wounding.