Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR

Bibliographic Details
Main Author:	Thees, Alison
Language:	English
Published:	University of Toledo Health Science Campus / OhioLINK 2018
Subjects:	Microbiology
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=mco15254429474901

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-mco152544294749012021-08-03T07:06:47Z Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR Thees, Alison Microbiology Harmful algal blooms (HABs) have been recorded in Lake Erie for decades, caused by years of eutrophication from agricultural runoff and effluent from municipal waste treatment plants. In the 1970s, the condition of the lake became so poor that the International Joint Commission implemented regulations to diminish phosphorus loading, which greatly improved the health of the lake, but HABs eventually returned to Lake Erie. In August 2014, the city of Toledo, Ohio was forced to issue a “do not drink” order that affected nearly 500,000 residents for three days due to the presence of unsafe levels of the HAB toxin microcystin LR (MC-LR) in drinking water. MC-LR and other cyanobacterial toxins pose significant health risks to humans, and the increasing incidences of Lake Erie HABs are a major public health concern. Given that MC-LR is composed of seven amino acids (or modified amino acids), we hypothesized that naturally-occurring Lake Erie bacteria could use MC-LR as an energy source. To test this hypothesis, water samples were collected from HABs in western Lake Erie during the summers of 2014-2017, MC-LR was continuously added to each water sample for 3-6 weeks to select for MC-LR degrading bacteria, and MC-LR levels were quantitated during the experiment. A total of 66 individual bacterial clones were isolated from MC-LR degrading water samples and were genotyped to exclude potential human pathogens. Next, the bacterial clones were examined either individually, or in groups, for their ability to degrade MC-LR, microcystin congeners MC-RR and MC-LA, and to form biofilms. Select groups also were tested for their ability to degrade MC-LR in lab-scale biofilters. Due to previous studies demonstrating that mlrABC were responsible for MC-LR degradation, we examined our MC-LR degraders for mlrABC but these genes were not detected, indicating that alternative MC-LR degradation pathways must be present in Lake Erie bacteria. Collectively, we were able to isolate and identify bacterial clones capable of degrading MC-LR and MC-RR; these bacterial clones formed robust biofilms, and degraded MC-LR on a lab scale biofilter. The results of these studies indicate the potential use of bacterial clones to remove MC-LR from drinking water. 2018-12-21 English text University of Toledo Health Science Campus / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=mco15254429474901 http://rave.ohiolink.edu/etdc/view?acc_num=mco15254429474901 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Microbiology
spellingShingle	Microbiology Thees, Alison Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR
author	Thees, Alison
author_facet	Thees, Alison
author_sort	Thees, Alison
title	Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR
title_short	Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR
title_full	Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR
title_fullStr	Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR
title_full_unstemmed	Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR
title_sort	identification and characterization of lake erie bacteria that degrade the microcystin toxin mc-lr
publisher	University of Toledo Health Science Campus / OhioLINK
publishDate	2018
url	http://rave.ohiolink.edu/etdc/view?acc_num=mco15254429474901
work_keys_str_mv	AT theesalison identificationandcharacterizationoflakeeriebacteriathatdegradethemicrocystintoxinmclr
_version_	1719453966510587904

Identification and Characterization of Lake Erie Bacteria that Degrade the Microcystin Toxin MC-LR

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