Expression of metallothionein and α-tubulin in heavy metaltolerant Anopheles gambiae sensu stricto (Diptera: Culicidae)
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Date
2009
Authors
Mirejia, Paul O.
Keating, Joseph
Hassanali, Ahmed
Impoinvil, Daniel E.
Mbogo, Charles M.
Njerib, Martha
Nyambaka, H. N.
Kenya, E.U.
Githure, John I
Beier, John C.
Journal Title
Journal ISSN
Volume Title
Publisher
National Institute of Health
Abstract
Anopheles mosquitoes have been shown to adapt to heavy metals in their natural habitats. In this
study we explored the possibility of using Anopheles gambiae sensu stricto as bio-reporters for
environmental heavy metal pollution through expressions of their metal responsive metallothionein
and α-tubulin genes. The study was undertaken with third instar larvae after selection by cadmium,
copper, or lead at LC30 through five successive generations. Expression levels were determined in
the fifth generation by semi quantitative RT-PCR on the experimental and control populations. The
data were analyzed using one-way ANOVA. The highest metallothionein (F3, 11= 4.574, P = 0.038)
and α-tubulin (F3,11= 12.961, P = 0.002) responses were observed in cadmium-tolerant treatments.
There was significantly higher expression of metallothionein in cadmium or copper treatments
relative to the control (P = 0.012), and in cadmium than in lead treatments (P = 0.044). Expressions
of α-tubulin were significantly higher in cadmium than in control treatments (P = 0.008). These
results demonstrate capacity of An. gambiae s.s. to develop tolerance to increased levels of heavy
metal challenge. The results also confirm the potential of heavy metal responsive genes in mosquitoes
as possible bio-indicators of heavy metal environmental pollution. How the tolerance and expressions
relate to An. gambiae s.s. fitness and vectorial capacity in the environment remains to be elucidated.
Description
Keywords
Anopheles gambiae s.s, heavy metals, tolerance, pollution, α-tubulin, metallothionein
Citation
Ecotoxicol Environ Saf. 2010 January; 73(1): 46–50.