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Waara, Karl-Otto
Publications (3 of 3) Show all publications
Waara, S., Gajewska, M., Cruz Blázquez, V., Alsbro, R., Norwald, P. & Waara, K.-O. (2015). Long term performance of an FWS wetland for post-tertiary treatment of sewage: the influence of flow, temperature and age on nitrogen removal. In: Gabriela Dotro & Vincent Gagnon (Ed.), Book of Abstracts: 6th International Symposium on Wetland Pollutant Dynamics and Control: Annual Conference of the Constructed Wetland Association: 13th to 18th September, 2015, York, United Kingdom. Paper presented at 6th International Symposium on Wetland Pollution Dynamics and Control, York, United Kingdom, 13th-18th of September, 2015 (pp. 38-39).
Open this publication in new window or tab >>Long term performance of an FWS wetland for post-tertiary treatment of sewage: the influence of flow, temperature and age on nitrogen removal
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2015 (English)In: Book of Abstracts: 6th International Symposium on Wetland Pollutant Dynamics and Control: Annual Conference of the Constructed Wetland Association: 13th to 18th September, 2015, York, United Kingdom / [ed] Gabriela Dotro & Vincent Gagnon, 2015, p. 38-39Conference paper, Oral presentation with published abstract (Other academic)
National Category
Natural Sciences
Identifiers
urn:nbn:se:hh:diva-30137 (URN)
Conference
6th International Symposium on Wetland Pollution Dynamics and Control, York, United Kingdom, 13th-18th of September, 2015
Available from: 2016-01-07 Created: 2016-01-07 Last updated: 2018-03-22Bibliographically approved
Urrutia-Cordero, P., Agha, R., Cires, S., Angeles Lezcano, M., Sanchez-Contreras, M., Waara, K.-O., . . . Quesada, A. (2013). Effects of harmful cyanobacteria on the freshwater pathogenic free-living amoeba Acanthamoeba castellanii. Aquatic Toxicology, 130, 9-17
Open this publication in new window or tab >>Effects of harmful cyanobacteria on the freshwater pathogenic free-living amoeba Acanthamoeba castellanii
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2013 (English)In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 130, p. 9-17Article in journal (Refereed) Published
Abstract [en]

Grazing is a major regulating factor in cyanobacterial population dynamics and, subsequently, considerable effort has been spent on investigating the effects of cyanotoxins on major metazoan grazers. However, protozoan grazers such as free-living amoebae can also feed efficiently on cyanobacteria, while simultaneously posing a major threat for public health as parasites of humans and potential reservoirs of opportunistic pathogens. In this study, we conducted several experiments in which the freshwater amoeba Acanthamoeba castellanii was exposed to pure microcystin-LR (MC-LR) and six cyanobacterial strains, three MC-producing strains (MC-LR, MC-RR, MC-YR, MC-WR, [Dha7] MC-RR) and three strains containing other oligopeptides such as anabaenopeptins and cyanopeptolins. Although the exposure to high concentrations of pure MC-LR yielded no effects on amoeba, all MC-producing strains inflicted high mortality rates on amoeba populations, suggesting that toxic effects must be mediated through the ingestion of toxic cells. Interestingly, an anabaenopeptin-producing strain caused the greatest inhibition of amoeba growth, indicating that toxic bioactive compounds other than MCs are of great importance for amoebae grazers. Confocal scanning microscopy revealed different alterations in amoeba cytoskeleton integrity and as such, the observed declines in amoeba densities could have indeed been caused via a cascade of cellular events primarily triggered by oligopeptides with protein-phosphatase inhibition capabilities such as MCs or anabaenopeptins. Moreover, inducible-defense mechanisms such as the egestion of toxic, MC-producing cyanobacterial cells and the increase of resting stages (encystation) in amoebae co-cultivated with all cyanobacterial strains were observed in our experiments. Consequently, cyanobacterial strains showed different susceptibilities to amoeba grazing which were possibly influenced by the potentiality of their toxic secondary metabolites. Hence, this study shows the importance of cyanobacterial toxicity against amoeba grazing and, that cyanobacteria may contain a wide range of chemical compounds capable of negatively affect free-living, herbivorous amoebae. Moreover, this is of high importance for understanding the interactions and population dynamics of such organisms in aquatic ecosystems. (c) 2012 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
Elsevier, 2013
Keywords
Cyanobacteria, Amoebae, Acanthamoeba castellanii, Grazing, Oligopeptide, Microcystin
National Category
Microbiology Pharmacology and Toxicology Microbiology in the medical area
Identifiers
urn:nbn:se:hh:diva-35452 (URN)10.1016/j.aquatox.2012.12.019 (DOI)000317701600002 ()23333903 (PubMedID)2-s2.0-84872476254 (Scopus ID)
Available from: 2017-11-22 Created: 2017-11-22 Last updated: 2018-03-23Bibliographically approved
Waara, S., Waara, K.-O., Forsberg, Å. & Fridolfsson, M. (2008). Performance of a Constructed Wetland System for Treatment of Landfill Leachate. In: Marie Townshend (Ed.), Proceedings Waste 2008: Waste and Resource Management – a Shared Responsibility. Paper presented at Waste 2008: Waste and Resource Management – a Shared Responsibility, Stratford-upon-Avon, Warwickshire, United Kingdom, 16-17 September, 2008 (pp. 655-667). Stanton-on-the-Wolds: Waste Conference Ltd.
Open this publication in new window or tab >>Performance of a Constructed Wetland System for Treatment of Landfill Leachate
2008 (English)In: Proceedings Waste 2008: Waste and Resource Management – a Shared Responsibility / [ed] Marie Townshend, Stanton-on-the-Wolds: Waste Conference Ltd. , 2008, p. 655-667Conference paper, Published paper (Refereed)
Abstract [en]

The performance of a constructed wetland for treatment of landfill leachate has been evaluated based upon data obtained during 4 years (2003-2006). It consists of a series of 10 ponds with a total capacity of 52.000 m3 covering 8 ha. Using univariate and multivariate statistics (PCA) the reduction pattern of a large number of chemical parameters including heavy metals has been investigated in 3 parts of the wetland with equal volume. Analyses show that many parameters are removed to the greatest extent in the first part of the system (e.g. many heavy metals, total suspended solids) or the second part of the system (N-NH4) while other parameters such as total nitrogen are more gradually reduced (10 ton/year removed).  Toxicity testing with 5 bioassays showed that toxicity was sometimes observed at the inlet but no toxicity was observed at the outlet for 4 of the test species. The data presented will be used for optimizing the treatment process as well as to improve the monitoring program.

Place, publisher, year, edition, pages
Stanton-on-the-Wolds: Waste Conference Ltd., 2008
Keywords
constructed wetlands, landfill leachate, PCA, toxicity, Nitrogen retention
National Category
Environmental Sciences Other Industrial Biotechnology Water Engineering Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:hh:diva-23589 (URN)10.13140/2.1.1940.6403 (DOI)9780953930142 (ISBN)0953930149 (ISBN)
Conference
Waste 2008: Waste and Resource Management – a Shared Responsibility, Stratford-upon-Avon, Warwickshire, United Kingdom, 16-17 September, 2008
Projects
Optimization of biological processes for treatment of landfill leachate
Available from: 2008-12-15 Created: 2013-09-17 Last updated: 2018-03-22Bibliographically approved
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