title: Impacts of chronic low-level nicotine exposure on Caenorhabditis elegans reproduction: identification of novel gene targets.
abstract: Effects and mechanisms of chronic exposure to low levels of nicotine is an area fundamentally important however less investigated. We employed the model organism Caenorhabditis elegans to investigate potential impacts of chronic (24h) and low nicotine exposure (6.17-194.5 μM) on stimulus-response, reproduction, and gene expressions. Nicotine significantly affects the organism's response to touch stimulus (p=0.031), which follows a dose-dependent pattern. Chronic nicotine exposure promotes early egg-laying events and slightly increased egg productions during the first 72 h of adulthood. The expressions of 10 (egl-10, egl-44, hlh-14, ric-3, unc-103, unc-50, unc-68, sod-1, oxi-1, and old-1) out of 18 selected genes were affected significantly. Other tested genes were cat-4, egl-19, egl-47, egl-5, lin-39, unc-43, pink-1, and age-1. Changes in gene expression were more evident at low dosages than at relatively high levels. Genes implicated in reproduction, cholinergic signaling, and stress response were regulated by nicotine, suggesting widespread physiological impacts of nicotine.
authors.affiliation: Department of Biology, East Carolina University, Greenville, NC 27858, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Smith
authors.forename: Yanqiong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Polli
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wu
authors.forename: Baohong
authors.initials: B
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Xiao
authors.forename: Mary A
authors.initials: MA
authors.lastname: Farwell
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Pan
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D009538:Nicotine / Q000633:toxicity*; D018722:Nicotinic Agonists / Q000633:toxicity*; D052287:Oviparity / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects
chemical_list: D029742:Caenorhabditis elegans Proteins; D018722:Nicotinic Agonists; D009538:Nicotine
keywords: C. elegans; Chronic exposure; Gene expression; Nicotine; Reproduction; Stress-response