Publications by authors named "Mi-Hee Ha"

The prevalence of cyanobacterial blooms in fresh water bodies worldwide has become a serious environmental problem. The blooms can increase the occurrence of cyanobacterial neurotoxin, anatoxin-a, and this toxin can interact with aquatic plants and other pivotal components of aquatic ecosystems. Despite this, several questions regarding the uptake of the toxin by aquatic plants and its association with toxic effects still remain.

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Recently, aquatic macrophytes have been considered as promising tools for eco-friendly water management with a low running cost. However, only little information is available thus far regarding the metabolic capacity of macrophytes for coping with cyanobacterial toxins (cyanotoxins) in the aquatic environment. Cyanotoxins have become emerging contaminants of great concern due to the high proliferation of cyanobacteria (cyanobacterial bloom) accelerated by eutrophication and climate change.

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Anatoxin-a is one of the common and major cyanobacterial neurotoxins acting as a powerful agonist at nicotinic acetylcholine receptors (nAChR). In recent years, the toxin has become the focus of public attention, due to the mass development of cyanobacteria (cyanobacterial blooms) in freshwater bodies triggered by eutrophication and climate change. Anatoxin-a is suspected to have a distinct toxic mechanism depending on physiological and nervous systems in exposed organisms.

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Daphnia hemoglobin (Hb) is one of the widely investigated invertebrate respiratory pigment. In this study, alteration of Daphnia magna Hb was evaluated in terms of its gene expression, using four D. magna Hb open reading frames (ORFs), by exposure of various chemicals, such as nonylphenol (NP), bisphenol A (BPA), benzo[a]pyrene (B[a]P), chloropyriphos (CP), paraquat dichloride (PQ), and lead nitrate (Pb), under laboratory conditions.

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In order to identify Chironomus hemoglobin (Hb) as a biomarker of ecotoxicity monitoring; herein, the effects of cadmium chloride (Cd) on Hb parameters were investigated in the 4th instar larvae of Chironomus riparius. The expressions of globin mRNA and hemolymph protein, using ecotoxicoproteomic approach, were investigated. Conventional ecotoxicity tests were also conducted to validate the ecotoxicological relevance of the response of Chironomus Hb as a biomarker.

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In this study, a preliminary characterization of the multiplicity of Chironomus hemoglobin (Hb) was conducted on the larvae of Chironomus tentans Mg. (Diptera: Chironomidae) by the molecular mass and isoelectric point. In order to identify Chironomus Hb as potential biomarker of environmental contamination, alteration of individual Hb by exposure to environmental chemicals, namely, nonylphenol, benzo[a]pyrene, chloropyriphos and cadmium chloride, were evaluated.

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The effects of environmental contaminants (i.e., nonylphenol, bisphenol A diglycidyl ether, benzo[a]pyrene, chlorpyriphos, paraquat dichloride, and lead nitrate) on Chironomus hemoglobin were investigated in the 4th instar larvae of Chironomus riparius (Diptera: Chironomidae), with respect to the total hemoglobin contents, individual globin gene expression, individual globin protein expression and hemoglobin oxidation.

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To test the suitability of cell bioassay as a tool for screening the toxicological risk of dioxin-like compounds, an in vitro toxicity assay was performed using samples obtained from small sized Korean waste incineration plants. Stress-related gene expression, cell viability, apoptosis, DNA damage and cell cycles were investigated as toxicological indicators of the polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) exposed human bronchial epithelial cell, Beas-2B. Of the stress-related genes, the expressions of the aryl hydrocarbon receptor (AhR), cytochrome P450 (CYP) and p53 genes were most significantly induced by exposure to PCDDs/DFs.

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