Nardi F

References (2)

Title : Acetylcholinesterase genes in the basal Hexapod Orchesella villosa - Nardi_2009_Insect.Mol.Biol_18_45
Author(s) : Nardi F , Barazzuoli B , Ciolfi S , Carapelli A , Dallai R , Frati F
Ref : Insect Molecular Biology , 18 :45 , 2009
Abstract : Acetylcholinesterase (AChE) is a key enzyme of the cholinergic nerve system. Of the two forms found in insects, the predominant one is active in the synapses and is the target of organophosphate and carbamate insecticides, while the role of the second is currently unknown. Two acetylcholinesterase cDNAs from the basal hexapod Orchesella villosa have been characterized and compared with others reported form insects. One form conforms well to the typical structure, while the other is characterized by an unusual 3' region. No amino acid mutation could be directly associated with known resistance mutations in other insect species or to a clear signal of selection in the distribution of alleles, although the action of some population process is suggested.
ESTHER : Nardi_2009_Insect.Mol.Biol_18_45
PubMedSearch : Nardi_2009_Insect.Mol.Biol_18_45
PubMedID: 19016914
Gene_locus related to this paper: orcvi-ACHE1 , orcvi-ACHE2

Title : Geographical distribution and evolutionary history of organophosphate-resistant Ace alleles in the olive fly (Bactrocera oleae) - Nardi_2006_Insect.Biochem.Mol.Biol_36_593
Author(s) : Nardi F , Carapelli A , Vontas J , Dallai R , Roderick GK , Frati F
Ref : Insect Biochemistry & Molecular Biology , 36 :593 , 2006
Abstract : Acetylcholinesterase (Ace) is the molecular target of organophosphate (OP) insecticides, and two mutations that confer different levels of OP insensitivity have previously been identified in the olive fly, Bactrocera oleae. Numerous sensitive and two insensitive alleles (including one convergent acquisition) are described from the entire worldwide distribution of the fly. Most of the variation is harbored in the native range of the species and in the Middle East and consists of numerous low-frequency sensitive alleles. The insensitive alleles likely came to high frequency more recently in the Mediterranean region or in the Middle East, reaching frequencies as high as 100% in some populations, and determined a corresponding decline in overall genetic variation. We hypothesize that the major force that shaped the current distribution of resistant and non-resistant acetylcholinesterase alleles is natural selection, likely responsible for the high frequency of insensitive alleles in areas where organophosphates have been used extensively. We also discuss a role for historical contingency, that can explain why sensitive alleles are absent altogether in the species ancestral range and present in areas of recent expansion, such as California, despite the limited use of OPs.
ESTHER : Nardi_2006_Insect.Biochem.Mol.Biol_36_593
PubMedSearch : Nardi_2006_Insect.Biochem.Mol.Biol_36_593
PubMedID: 16835025
Gene_locus related to this paper: bacol-ACHE