Table 5.

Mean (±SE) levels of altered acethylcholinesterase (AchE), non-specific esterases (α- and β-esterase), glutathione S-transferase (GST) and monooxygenase (MFO) activities of Ae. aegypti adults collected from different locations in Singapore

Strain	n	Mean enzyme activities 1 (Mean 2  ± SE)
		AchE	α-Esterase	β-Esterase	GST	MFO
Bora-bora	93	30.13 ± 0.67	21.51 ± 0.70	23.61 ± 0.74	0.04 ± 0.00	0.13 ± 0.01
Ang Mo Kio	79	33.98 ± 0.44*	22.23 ± 0.56	23.96 ± 0.81	0.06 ± 0.00	0.02 ± 0.00*
Jurong East	94	32.55 ± 1.08	2.08 ± 1.80*	1.93 ± 1.69*	0.05 ± 0.00	0.53 ± 0.02*
Yishun	82	46.35 ± 0.97*	15.99 ± 0.42*	19.67 ± 0.57*	0.04 ± 0.00	0.22 ± 0.01*
Chua Chu Kang	81	38.31 ± 0.55*	7.85 ± 0.32*	10.60 ± 0.47*	0.05 ± 0.00	0.14 ± 0.00*
Clementi	44	34.25 ± 1.49*	17.78 ± 0.81*	19.09 ± 1.03*	1.99 ± 0.04*	0.13 ± 0.01
Pasir Ris	47	33.85 ± 0.66*	9.54 ± 0.44*	12.67 ± 0.55*	0.04 ± 0.00	0.01 ± 0.00*
Woodlands	32	27.41 ± 1.10*	13.75 ± 0.81*	14.72 ± 0.96*	0.04 ± 0.00	0.20 ± 0.01*

¹Enzyme activities are expressed as the reaction rate of different substrates/min/mg protein. ²Means followed by the asterisk are significantly different compared to the Bora-Bora strain (p < 0.05, two samples t-test or Mann–Whitney test). AchE: percentage insensitive acethylcholinesterase activity after propoxur inhibition. α-esterase: nmole of 1-naphthol/min/mg protein, β-esterase: nmole of 1-naphthol/min./mg protein. GST: mMole of CDNB/min/mg protein. MFO: nmole equivalent unit cyt P450/min/mg protein. The results in bold denotes activity that is more than two times above the control.