Prokaryotic aminopeptidase activity along a continuous salinity gradient in a hypersaline coastal lagoon (the Coorong, South Australia)

Type Article
Date 2010-04
Language English
Author(s) Pollet Thoams1, 2, Schapira Mathilde1, 3, Buscot Marie-Jeanne1, Leterme Sophie1, 4, Mitchell James G1, Seuront Laurent1, 4, 5, 6
Affiliation(s) 1 : School of Biological Sciences, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
2 : MR CARRTEL, Centre Alpin de Recherche sur les Réseaux Trophiques des Ecosystèmes Limniques, Station d'Hydrobiologie Lacustre, Université de Savoie, 75 avenue de Corzent, BP 511, Thonon les Bains Cedex, 74203, France
3 : Southern Ocean Group, Dept. of Zoology & Entomology, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa
4 : South Australian Research and Development Institute, Aquatic Sciences, West Beach, SA, 5022, Australia
5 : Center for Polymer Studies, Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, MA, 02215, USA
6 : Centre National de la Recherche Scientifique, France
Source Saline Systems (1746-1448) (BioMed Central Ltd), 2010-04 , Vol. 6 , N. 5 , P. 1-6
DOI 10.1186/1746-1448-6-5
Abstract he distribution and aminopeptidase activity of prokaryotes were investigated along a natural continuous salinity gradient in a hypersaline coastal lagoon, the Coorong, South Australia. The abundance of prokaryotes significantly increased from brackish to hypersaline waters and different sub-populations, defined by flow cytometry, were observed along the salinity gradient. While four sub-populations were found at each station, three additional ones were observed for 8.3% and 13.4%, suggesting a potential modification in the composition of the prokaryotic communities and/or a variation of their activity level along the salinity gradient. The aminopeptidase activity highly increased along the gradient and salinity appeared as the main factor favouring this enzymatic activity. However, while the aminopeptidase activity was dominated by free enzymes for salinities ranging from 2.6% to 13.4%, cell-attached aminopeptidase activity was predominant in more saline waters (i.e. 15.4%). Changes in substrate structure and availability, strongly related to salinity, might (i) modify patterns of both aminopeptidase activities (free and cell-associated enzymes) and (ii) obligate the prokaryotic communities to modulate rapidly their aminopeptidase activity according to the nutritive conditions available along the gradient.
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Pollet Thoams, Schapira Mathilde, Buscot Marie-Jeanne, Leterme Sophie, Mitchell James G, Seuront Laurent (2010). Prokaryotic aminopeptidase activity along a continuous salinity gradient in a hypersaline coastal lagoon (the Coorong, South Australia). Saline Systems, 6(5), 1-6. Publisher's official version : , Open Access version :