title: Cadmium uptake capacity of an indigenous cyanobacterial strain, Nostoc entophytum ISC32: new insight into metal uptake in microgravity-simulating conditions.
abstract: Among nine cyanobacterial strains isolated from oil-contaminated regions in southern Iran, an isolate with maximum cadmium uptake capacity was selected and identified on the basis of analysis of morphological criteria and 16S rRNA gene sequence similarity as Nostoc entophytum (with 99% similarity). The isolate was tentatively designated N. entophytum ISC32. The phylogenetic affiliation of the isolates was determined on the basis of their 16S rRNA gene sequence. The maximum amount of Cd(II) adsorbed by strain ISC32 was 302.91 mg g(-1) from an initial exposure to a solution with a Cd(II) concentration of 150 mg l(-1). The cadmium uptake by metabolically active cells of cyanobacterial strain N. entophytum ISC32, retained in a clinostat for 6 days to simulate microgravity conditions, was examined and compared with that of ground control samples. N. entophytum ISC32 under the influence of microgravity was able to take up cadmium at amounts up to 29% higher than those of controls. The activity of antioxidant enzymes including catalase and peroxidase was increased in strain ISC32 exposed to microgravity conditions in a clinostat for 6 days, as catalase activity of the cells was more than three times higher than that of controls. The activity of the peroxidase enzyme increased by 36% compared with that of the controls. Membrane lipid peroxidation was also increased in the cells retained under microgravity conditions, up to 2.89-fold higher than in non-treated cells. Images obtained using scanning electron microscopy showed that cyanobacterial cells form continuous filaments which are drawn at certain levels, while the cells placed in a clinostat appeared as round-shaped, accumulated together and distorted to some extent.
authors.affiliation: Division of Industrial & Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran.
authors.forename: Leila
authors.initials: L
authors.lastname: Alidoust
authors.affiliation: Department of Petroleum Microbiology, ACECR, Research Institute of Applied Science, Shahid Beheshti University, Tehran, Iran.
authors.forename: Neda
authors.initials: N
authors.lastname: Soltani
authors.affiliation: Division of Industrial & Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran.
authors.forename: Sima
authors.initials: S
authors.lastname: Modiri
authors.affiliation: Division of Industrial & Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran.
authors.forename: Omid
authors.initials: O
authors.lastname: Haghighi
authors.affiliation: Division of Industrial & Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran.
authors.forename: Aisan
authors.initials: A
authors.lastname: Azarivand
authors.affiliation: Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Khosro
authors.initials: K
authors.lastname: Khajeh
authors.affiliation: Division of Industrial & Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Shahbani Zahiri
authors.affiliation: Facility for Electron Microscopy Research, McGill University, 3640 Street, Montreal, Canada.
authors.forename: Hojatollah
authors.initials: H
authors.lastname: Vali
authors.affiliation: Division of Industrial & Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), PO Box 14155-6343, Tehran, Iran.
authors.forename: Kambiz
authors.initials: K
authors.lastname: Akbari Noghabi
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001692:Biological Transport / Q000502:physiology*; D018533:Biomass; D002104:Cadmium / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004785:Environmental Pollutants / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000502:physiology; D008563:Membrane Lipids / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D046937:Nostoc / Q000235:genetics / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014893:Weightlessness
chemical_list: D000975:Antioxidants; D004785:Environmental Pollutants; D008563:Membrane Lipids; D012336:RNA, Ribosomal, 16S; D002104:Cadmium; D002374:Catalase; D009195:Peroxidase