title: Aldehyde dehydrogenase expression in Metaphire posthuma as a bioindicator to monitor heavy metal pollution in soil.
abstract: BACKGROUND
  Soil contamination and associated pollution plays a detrimental role in soil flora and fauna. Soil is processed and remodeled by subterranean earthworms, accordingly are referred to as soil chemical engineers. These worms, besides processing carbon and nitrogen, serve as minors for processing metals. In heavy metal contaminated soils, they accumulate heavy metals, which in turn cause altered gene expression, including aldehyde dehydrogenase (ALDH) enzymes. This study explores the possibility of ALDH expression in earthworms as a novel biomarker for the heavy metal contamination of soil.
  
  
  RESULTS
  Earthworms cultured in contaminated soils accumulated significantly higher levels of Pb and Cd. Similarly, significantly higher levels of ALDH enzyme activities were observed in earthworms cultured in soils contaminated with Pb and Cd. The ALDH activity was found to be highest in worms cultured in 5 ppm heavy metal contaminated soils. Although, ALDH activities decreased as the heavy metal concentration in soil increased, they were significantly higher when compared to control worms cultured in uncontaminated soils. The accumulation of heavy metal in earthworms measured after 28 days decreased as the heavy metal concentration in soil increased.
  
  
  CONCLUSIONS
  Levels of ALDH expression correlated with total Pb and Cd concentration in the earthworm tissue. This study showed that the ALDH activity in earthworms could potentially be used as a biomarker to show heavy metal pollution in soil.
authors.affiliation: Central Department of Biotechnology, Tribhuvan University, Kathmandu, Nepal. raju.panday@hotmail.com.
authors.forename: Raju
authors.initials: R
authors.lastname: Panday
authors.affiliation: Central Department of Biotechnology, Tribhuvan University, Kathmandu, Nepal.
authors.forename: Padam Shekhar
authors.initials: PS
authors.lastname: Bhatt
authors.affiliation: Central Department of Biotechnology, Tribhuvan University, Kathmandu, Nepal.
authors.forename: Tribikram
authors.initials: T
authors.lastname: Bhattarai
authors.affiliation: Department of Botany, Amrit Science Campus, Lainchaur, Kathmandu, Nepal.
authors.forename: Kumudini
authors.initials: K
authors.lastname: Shakya
authors.affiliation: Department of Chemistry and Biochemistry, St. Cloud State University, St. Cloud, MN, USA.|Department of Chemistry and Earth Sciences, Qatar University, Doha, Qatar.
authors.forename: Lakshmaiah
authors.initials: L
authors.lastname: Sreerama
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001673:Biodegradation, Environmental; D015374:Biosensing Techniques; D002104:Cadmium / Q000302:isolation & purification / Q000378:metabolism*; D057075:Enzyme Assays; D015870:Gene Expression; D007854:Lead / Q000302:isolation & purification / Q000378:metabolism*; D009835:Oligochaeta / Q000201:enzymology*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D000444:Aldehyde Dehydrogenase
keywords: Aldehyde dehydrogenase; Bioindicators; Cadmium (Cd); Heavy metals; Lead (Pb); Metaphire posthuma