title: Resistance Mechanisms of Anopheles stephensi (Diptera: Culicidae) to Temephos.
abstract: BACKGROUND
  Anopheles stephensi is a sub-tropical species and has been considered as one of the most important vector of human malaria throughout the Middle East and South Asian region including the malarious areas of southern Iran. Current reports confirmed An. stephensi resistance to temephos in Oman and India. However, there is no comprehensive research on mechanisms of temephos resistance in An. stephensi in the literature. This study was designed in order to clarify the enzymatic and molecular mechanisms of temephos resistance in this species.
  
  
  METHODS
  Profile activities of α- and ß-esterases, mixed function oxidase (MFO), glutathione-S-transferase (GST), insensitive acetylcholinesterase, and para-nitrophenyl acetate (PNPA)-esterase enzymes were tested for An. stephensi strain with resistance ratio of 15.82 to temephos in comparison with susceptible strain.
  
  
  RESULTS
  Results showed that the mean activity of α-EST, GST and AChE enzymes were classified as altered indicating metabolic mechanisms have considerable role in resistance of An. stephensi to temephos. Molecular study using PCR-RFLP method to trace the G119S mutation in ACE-1 gene showed lack of the mutation responsible for organophosphate insecticide resistance in the temephos-selected strain of An. stephensi.
  
  
  CONCLUSIONS
  This study showed that the altered enzymes but not targets site insensitivity of ACE-1 are responsible for temephos resistance in An. stephensi in south of Iran.
authors.affiliation: Department of Medical Entomology and vector control, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran ; Department of Medical Entomology and Vector Control, School of Public Health and National Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Aboozar
authors.initials: A
authors.lastname: Soltani
authors.affiliation: Department of Medical Entomology and Vector Control, School of Public Health and National Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Vatandoost
authors.affiliation: Department of Medical Entomology and Vector Control, School of Public Health and National Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Oshaghi
authors.affiliation: Department of Medical Entomology and Vector Control, School of Public Health and National Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Naseh Maleki
authors.initials: NM
authors.lastname: Ravasan
authors.affiliation: School of Public Health and Health Research Centre, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Ahmad Ali
authors.initials: AA
authors.lastname: Enayati
authors.affiliation: School of Public Health and Health Research Centre, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Asgarian
keywords: Acetylcholinesterase gene; Anopheles stephensi; malaria; mechanisms of resistance; temephos