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Mathias Ahii Chia
Department of Biological Sciences, Luiz de Queiroz College of Agriculture, University of Sao Paulo, Piracicaba, Brazil

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Primary research paper
Published: 21 July 2021 in Hydrobiologia
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Phytoplankton allelopathic studies have mostly been restricted methodologically, leading to very limited quantitative physiological data. In the present study, investigations were carried out to determine physiological changes that occur during allelopathic interactions between chlorophytes (Chlamydomonas reinhardtii P.A. Dangeard 1888; Selenastrum sp.) and cyanobacteria (Microcystis aeruginosa (Kützing) Kützing, Microcystis sp. SR, Anabaena variabilis Kützing ex Bornet & Flahault 1886) using nylon membrane partitioned chambers. The growth of the cyanobacteria and chlorophytes were both stimulated and inhibited in a species-dependent manner. Among the chlorophytes, the Fv/Fm values of Selenastrum were significantly inhibited by Microcystis LE3 and Anabaena UTEX B377 during co-cultivation. There was a significant change in the Fv/Fm values of Anabaena UTEX B377 during co-cultivation with Chlamydomonas CC-503 and Selenastrum. Total microcystins content of Microcystis LE3 significantly declined during co-cultivation with Chlamydomonas CC-503 and Selenastrum. Nitrogen fixation by Anabaena UTEX B377 was significantly lowered in the presence of Microcystis LE3, Microcystis SR, Chlamydomonas CC-503, and Selenastrum. Antioxidant enzyme activities of the investigated chlorophytes and cyanobacteria were altered during allelopathic interactions with each other. These results revealed that phytoplankton species undergo various physiological changes during allelopathic interactions.

ACS Style

Mathias Ahii Chia; Maria Do Carm Bittencourt-Oliveira. Allelopathic interactions between phytoplankton species alter toxin production, oxidative response, and nitrogen fixation. Hydrobiologia 2021, 1 -13.

AMA Style

Mathias Ahii Chia, Maria Do Carm Bittencourt-Oliveira. Allelopathic interactions between phytoplankton species alter toxin production, oxidative response, and nitrogen fixation. Hydrobiologia. 2021; ():1-13.

Chicago/Turabian Style

Mathias Ahii Chia; Maria Do Carm Bittencourt-Oliveira. 2021. "Allelopathic interactions between phytoplankton species alter toxin production, oxidative response, and nitrogen fixation." Hydrobiologia , no. : 1-13.

Article
Published: 08 May 2021 in Environmental Biology of Fishes
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The increased production, consumption, and release of antibiotics account for their frequent contamination of aquatic ecosystems and detection in different biological matrices. Several antibiotics affect non-target organisms such as algae, cyanobacteria, zooplankton, and fish, making investigations on them very crucial for the health and maintenance of biodiversity. The impact of broad-spectrum antibiotics like ciprofloxacin (CPX) on toxin-producing and non-toxin-producing cyanobacteria has been poorly investigated. Therefore, the present study investigated the physiological and toxicological effects of CPX on Microcystis aeruginosa EAWAG 198, Microcystis aeruginosa LE3, and Microcystis flos-aquae UTEX-LB 2677. CPX caused a significant (p < 0.05) decrease in the cell densities and chlorophyll-a of the three strains. The antibiotic caused oxidative stress in all the strains, as demonstrated by a significant rise in the levels of intracellular hydrogen peroxide (H2O2) of the treated cultures at 96 h post-exposure. Lipid peroxidation and the activity of the antioxidant enzyme—peroxidase (POD) and glutathione-S-transferase (GST)—of the cultures were significantly (p < 0.05) altered. Exposure to CPX generally stimulated the production of biomolecules such as total proteins, lipids, and total carbohydrates as a function of increasing exposure concentration. The exception to the general trend was M. aeruginosa EAWAG 198, a non-toxin-producing strain, which suffered a significant decline in carbohydrate content during exposure to CPX. This study revealed that environmentally relevant levels of CPX could alter the population dynamics, photosynthesis, biochemical composition, and the general physiology of Microcystis species/strains in aquatic ecosystems.

ACS Style

Abraham Gana Yisa; Mathias Ahii Chia; Ramatu Idris Sha’Aba; Balli Gauji; Ibrahim Madu Katsallah Gadzama; Sonnie Joshua Oniye. The antibiotic ciprofloxacin alters the growth, biochemical composition, and antioxidant response of toxin-producing and non-toxin-producing strains of Microcystis. Environmental Biology of Fishes 2021, 33, 2145 -2155.

AMA Style

Abraham Gana Yisa, Mathias Ahii Chia, Ramatu Idris Sha’Aba, Balli Gauji, Ibrahim Madu Katsallah Gadzama, Sonnie Joshua Oniye. The antibiotic ciprofloxacin alters the growth, biochemical composition, and antioxidant response of toxin-producing and non-toxin-producing strains of Microcystis. Environmental Biology of Fishes. 2021; 33 (4):2145-2155.

Chicago/Turabian Style

Abraham Gana Yisa; Mathias Ahii Chia; Ramatu Idris Sha’Aba; Balli Gauji; Ibrahim Madu Katsallah Gadzama; Sonnie Joshua Oniye. 2021. "The antibiotic ciprofloxacin alters the growth, biochemical composition, and antioxidant response of toxin-producing and non-toxin-producing strains of Microcystis." Environmental Biology of Fishes 33, no. 4: 2145-2155.

Journal article
Published: 21 March 2021 in Science of The Total Environment
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Anthropogenic activities have led to the depletion of the ultraviolet radiation screening ozone layer, exposing aquatic biota to its harmful effects. Also, the rising applications of nanotechnology are resulting in the release and contamination of aquatic ecosystems with engineered nanometals like titanium dioxide nanoparticles (nTiO2). The rise in ultraviolet radiation interacts with nanometals, increasing their bioactivities to susceptible aquatic organisms such as algae and cyanobacteria. The effect of ultraviolet radiation B (UVB) and nTiO2 on Microcystis flos-aquae and Pseudokirchneriella subcapitata during inter-specific interaction was investigated. The specific growth rate (d−1) of M. flos-aquae exposed to nTiO2 increased significantly under monoculture conditions but was suppressed during co-culture with P. subcapitata. Contrarily, UVB stimulated the growth of the cyanobacterium regardless of the presence or absence of the green microalgae. However, there was a general decline in the growth of P. subcapitata following cultivation with M. flos-aquae and exposure to UVB and nTiO2. The chlorophyll-a and total chlorophyll content of the monocultures of M. flos-aquae exposed to nTiO2 increased while other co-culture treatments significantly decreased these parameters. The experimental treatments, UVB, nTiO2, and UVB + nTiO2 had differential effects on the pigment content of P. subcapitata. The total protein content, intracellular H2O2, peroxidase (POD), and glutathione S-transferase (GST) activity of both M. flos-aquae and P. subcapitata increased at varying degrees as a function of the treatment condition. Microcystin content was highest in co-cultures exposed to UVB. The results of this study suggest that increasing levels of nTiO2 and UVB significantly alter the growth and cellular metabolic activity of M. flos-aquae and P. subcapitata, but the cyanobacterium will probably be favored by increasing UVB levels and its interaction with nanometals like nTiO2 in aquatic ecosystems.

ACS Style

Regina Anya Otogo; Mathias Ahii Chia; Ejiroghene Ebelechukwu Uyovbisere; Dora Nguemo Iortsuun; Maria Do Carmo Bittencourt-Oliveira. Effect of ultraviolet radiation (type B) and titanium dioxide nanoparticles on the interspecific interaction between Microcystis flos-aquae and Pseudokirchneriella subcapitata. Science of The Total Environment 2021, 779, 146561 .

AMA Style

Regina Anya Otogo, Mathias Ahii Chia, Ejiroghene Ebelechukwu Uyovbisere, Dora Nguemo Iortsuun, Maria Do Carmo Bittencourt-Oliveira. Effect of ultraviolet radiation (type B) and titanium dioxide nanoparticles on the interspecific interaction between Microcystis flos-aquae and Pseudokirchneriella subcapitata. Science of The Total Environment. 2021; 779 ():146561.

Chicago/Turabian Style

Regina Anya Otogo; Mathias Ahii Chia; Ejiroghene Ebelechukwu Uyovbisere; Dora Nguemo Iortsuun; Maria Do Carmo Bittencourt-Oliveira. 2021. "Effect of ultraviolet radiation (type B) and titanium dioxide nanoparticles on the interspecific interaction between Microcystis flos-aquae and Pseudokirchneriella subcapitata." Science of The Total Environment 779, no. : 146561.

Article
Published: 21 March 2021 in Aquatic Ecology
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Agrochemicals such as herbicides change the physical and chemical conditions of aquatic ecosystems and alter the community structure and dynamics of phytoplankton. Cyanobacteria are photosynthetic organisms found at the base of aquatic food chains. When cyanobacteria form blooms and produce toxins, they harm humans and the environment. Herbicides contaminate the aquatic environment when they are leached and transported via surface runoff from farms and industries. In this review, we show that these compounds have different mechanisms of action, but at high concentrations, they cause oxidative stress, interfere with the normal functioning of enzymes, and change the metabolic profile of microalgae and cyanobacteria. This paper demonstrates that at environmentally relevant concentrations, some herbicides facilitate the formation of cyanobacterial harmful algal blooms (cyanoHABs). The formation of blooms is driven by the tolerance of cyanobacteria to herbicides, where some of these compounds are degraded and converted into non-toxic forms. The degradation by-products are also used as a source of nutrients to support cyanobacterial growth. This adaptation sometimes leads to higher concentrations of bioactive compounds such as cyanotoxins in the aquatic environment. The increased levels of cyanotoxins and herbicides in water bodies can trigger a cascading toxicological effect on non-targeted organisms and the aquatic food chain. Despite the evidence confirming herbicides influence the growth of cyanobacteria and alter the structure of the phytoplankton community toward the formation of cyanoHABs, there is a lot that remains to be done to fully understand their impact on these organisms.

ACS Style

Fernanda Brêda-Alves; Valéria De Oliveira Fernandes; Mathias Ahii Chia. Understanding the environmental roles of herbicides on cyanobacteria, cyanotoxins, and cyanoHABs. Aquatic Ecology 2021, 55, 347 -361.

AMA Style

Fernanda Brêda-Alves, Valéria De Oliveira Fernandes, Mathias Ahii Chia. Understanding the environmental roles of herbicides on cyanobacteria, cyanotoxins, and cyanoHABs. Aquatic Ecology. 2021; 55 (2):347-361.

Chicago/Turabian Style

Fernanda Brêda-Alves; Valéria De Oliveira Fernandes; Mathias Ahii Chia. 2021. "Understanding the environmental roles of herbicides on cyanobacteria, cyanotoxins, and cyanoHABs." Aquatic Ecology 55, no. 2: 347-361.

Review
Published: 15 March 2021 in Aquatic Toxicology
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Human and veterinary pharmaceuticals either in the form of un-metabolized, incompletely metabolized, and metabolized drugs are increasingly present in aquatic ecosystems. These active pharmaceutical ingredients from pharmaceutical industries, hospitals, agricultural, and domestic discharges find their way into water systems – where they adversely affect non-target organisms like phytoplankton. Different aspects of phytoplankton life; ranging from growth, reproduction, morphology, physiology, biochemical composition, oxidative response, proteomics, and transcriptomics are altered by pharmaceuticals. This review discusses the currently available information on the susceptibility of phytoplankton to the ever-increasing presence of pharmaceutical products in the aquatic environment by focusing on the effect of APIs on the physiology, metabolome, and proteome profiles of phytoplankton. We also highlight gaps in literature concerning the salient underlining biochemical interactions between phytoplankton communities and pharmaceuticals that require an in-depth investigation. This is all in a bid to understand the imminent dangers of the contamination of water bodies with pharmaceutical products and how this process unfavorably affects aquatic food webs.

ACS Style

Mathias Ahii Chia; Adriana Sturion Lorenzi; Ilu Ameh; Suleiman Dauda; Micheline Kézia Cordeiro-Araújo; Jerry Tersoo Agee; Ibrahim Yusuf Okpanachi; Abosede Taofikat Adesalu. Susceptibility of phytoplankton to the increasing presence of active pharmaceutical ingredients (APIs) in the aquatic environment: A review. Aquatic Toxicology 2021, 234, 105809 .

AMA Style

Mathias Ahii Chia, Adriana Sturion Lorenzi, Ilu Ameh, Suleiman Dauda, Micheline Kézia Cordeiro-Araújo, Jerry Tersoo Agee, Ibrahim Yusuf Okpanachi, Abosede Taofikat Adesalu. Susceptibility of phytoplankton to the increasing presence of active pharmaceutical ingredients (APIs) in the aquatic environment: A review. Aquatic Toxicology. 2021; 234 ():105809.

Chicago/Turabian Style

Mathias Ahii Chia; Adriana Sturion Lorenzi; Ilu Ameh; Suleiman Dauda; Micheline Kézia Cordeiro-Araújo; Jerry Tersoo Agee; Ibrahim Yusuf Okpanachi; Abosede Taofikat Adesalu. 2021. "Susceptibility of phytoplankton to the increasing presence of active pharmaceutical ingredients (APIs) in the aquatic environment: A review." Aquatic Toxicology 234, no. : 105809.

Journal article
Published: 11 March 2021 in Environmental Toxicology and Pharmacology
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Lumefantrine is used to treat uncomplicated malaria caused by pure or mixed Plasmodium falciparum infections and as a prophylactic against recrudescence following artemether therapy. However, the pharmaceutical is released into the aquatic environment from industrial effluents, hospital discharges, and human excretion. This study assessed the effects of lumefantrine on the growth and physiological responses of the microalgae Chlorella vulgaris and Raphidocelis subcapitata (formerly known as Selenastrum capricornutum and Pseudokirchneriella subcapitata) and the aquatic macrophyte Lemna minor. The microalgae and macrophyte were exposed to 200−10000 μg l−1 and 16−10000 μg l−1 lumefantrine, respectively. Lumefantrine had a variable effect on the growth of the aquatic plants investigated. There was a decline in the growth of R. subcapitata and L. minor post-exposure to the drug. Contrarily, there was stimulation in the growth of Chlorella vulgaris. All experimental plants had a significant increase in lipid peroxidation, which was accompanied by an increase in malondialdehyde content. Peroxidase activity of L. minor increased only at low lumefantrine concentrations, while the opposite occurred at higher levels of the drug. Incubation in lumefantrine contaminated medium significantly up-regulated the activity of R. subcapitata cultures. Glutathione S-transferase of L. minor exposed to lumefantrine treatments had substantially higher activities than the controls. Our findings suggest lumefantrine could have adverse but variable effects on the growth and physiology of the studied aquatic plants.

ACS Style

Mathias Ahii Chia; Ilu Ameh; Jerry Tersoo Agee; Regina Anya Otogo; Ahmad Fatima Shaba; Hadiza Bashir; Fatima Umar; Abraham Gana Yisa; Ejiroghene Ebelechukwu Uyovbisere; Ramatu Idris Sha’Aba. Effects of the antimalarial lumefantrine on Lemna minor, Raphidocelis subcapitata and Chlorella vulgaris. Environmental Toxicology and Pharmacology 2021, 85, 103635 .

AMA Style

Mathias Ahii Chia, Ilu Ameh, Jerry Tersoo Agee, Regina Anya Otogo, Ahmad Fatima Shaba, Hadiza Bashir, Fatima Umar, Abraham Gana Yisa, Ejiroghene Ebelechukwu Uyovbisere, Ramatu Idris Sha’Aba. Effects of the antimalarial lumefantrine on Lemna minor, Raphidocelis subcapitata and Chlorella vulgaris. Environmental Toxicology and Pharmacology. 2021; 85 ():103635.

Chicago/Turabian Style

Mathias Ahii Chia; Ilu Ameh; Jerry Tersoo Agee; Regina Anya Otogo; Ahmad Fatima Shaba; Hadiza Bashir; Fatima Umar; Abraham Gana Yisa; Ejiroghene Ebelechukwu Uyovbisere; Ramatu Idris Sha’Aba. 2021. "Effects of the antimalarial lumefantrine on Lemna minor, Raphidocelis subcapitata and Chlorella vulgaris." Environmental Toxicology and Pharmacology 85, no. : 103635.

Journal article
Published: 28 December 2020 in Environmental Pollution
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Several studies have reported the contamination of farmed fish by microcystins, however, alternations in levels of contamination resulting from seasonal changes are infrequently described. This investigation is focused on the seasonal accumulation of microcystins in farmed Nile Tilapia muscle tissue across three farms located in Zaria, Nigeria, as a means of assessing the health risks associated with the consumption of contaminated fish. Total microcystins and cyanobacteria content, respectively, in muscle tissue and gut of tilapia varied, seasonally in the farms. Microcystin levels were higher in fish tissues analyzed in the dry season than the rainy season at Nagoyi and Danlami ponds. Correlating with the levels of microcystins found in fish tissues, the highest dissolved microcystins levels in all the fish farms occurred in the dry season, where the Bal and Kol fish farm had the highest concentration (0.265 ± 0.038 μgL−1). Gut analysis of fish obtained from the ponds, revealed a predominance of Microcystis spp. among other cyanobacteria. Estimation of total daily intake of consumed contaminated Nile tilapia muscles reveal values exceeding WHO recommended (0.04 μg kg−1 body weight) total daily intake of MC-LR. Consumption of tilapia from Danlami pond presented the greatest risk with a value of 0.093 μg kg−1 total daily intake. Results of the present study necessitate the implementation of legislation and monitoring programs for microcystins and other cyanobacteria contaminants of fish obtained from farms and other sources in Zaria and indeed several other African countries.

ACS Style

Mathias Ahii Chia; Rabiu Abdulwahab; Ilu Ameh; J. Kolawole Balogun; Jehu Auta. Farmed tilapia as an exposure route to microcystins in Zaria-Nigeria: A seasonal investigation. Environmental Pollution 2020, 271, 116366 .

AMA Style

Mathias Ahii Chia, Rabiu Abdulwahab, Ilu Ameh, J. Kolawole Balogun, Jehu Auta. Farmed tilapia as an exposure route to microcystins in Zaria-Nigeria: A seasonal investigation. Environmental Pollution. 2020; 271 ():116366.

Chicago/Turabian Style

Mathias Ahii Chia; Rabiu Abdulwahab; Ilu Ameh; J. Kolawole Balogun; Jehu Auta. 2020. "Farmed tilapia as an exposure route to microcystins in Zaria-Nigeria: A seasonal investigation." Environmental Pollution 271, no. : 116366.

Research article
Published: 30 October 2020 in Environmental Science and Pollution Research
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The large-scale use of herbicides deteriorates water quality and threatens aquatic biodiversity. Unfortunately, there are few studies on the ecological effects of herbicides on toxin-producing strains of cyanobacteria under changing nutrient conditions. The objective of the present study was to investigate the effects of the herbicide clethodim and nitrogen variation on the allelopathic interactions and toxin production of Microcystis aeruginosa BCCUSP232 and Raphidiopsis raciborskii (formerly known as Cylindrospermopsis raciborskii) ITEPA1. M. aeruginosa had increased cell density when exposed to the clethodim (H +) (23.55 mg/L), whereas the highest cell density of R. raciborskii was observed in the treatment with clethodim plus limited nitrogen. Also, the cell-free exudate of R. raciborskii significantly stimulated the growth of M. aeruginosa on day 3 of the experiment. The concentration of chlorophyll-a in M. aeruginosa cultures generally increased in all the treatments, while in R. raciborskii cultures, the opposite occurred. Total microcystins (MCs) content of M. aeruginosa in the mixed cultures was 68% higher in nitrogen-enriched conditions than the control. A similar increase in MC content occurred in M. aeruginosa unialgal culture treated with R. raciborskii exudate. Total saxitoxin concentration was 81% higher in mixed cultures of R. raciborskii simultaneously exposed to high nitrogen and clethodim. Similarly, unialgal cultures of R. raciborskii exposed to either high nitrogen or clethodim had higher saxitoxins concentrations than the control. The intracellular H2O2 content of M. aeruginosa cultures decreased, whereas, in R. raciborskii cultures, it increased during exposure to high nitrogen and clethodim. Only R. raciborskii had a significant variation in peroxidase activity. The activities of glutathione S-transferase of both strains were higher in the presence of clethodim. These results revealed that nitrogen enrichment and the presence of clethodim might lead to the excessive proliferation of M. aeruginosa and R. raciborskii and increased production of cyanotoxins in aquatic environments.

ACS Style

Fernanda Brêda-Alves; Valéria De Oliveira Fernandes; Micheline Kézia Cordeiro-Araújo; Mathias Ahii Chia. The combined effect of clethodim (herbicide) and nitrogen variation on allelopathic interactions between Microcystis aeruginosa and Raphidiopsis raciborskii. Environmental Science and Pollution Research 2020, 28, 11528 -11539.

AMA Style

Fernanda Brêda-Alves, Valéria De Oliveira Fernandes, Micheline Kézia Cordeiro-Araújo, Mathias Ahii Chia. The combined effect of clethodim (herbicide) and nitrogen variation on allelopathic interactions between Microcystis aeruginosa and Raphidiopsis raciborskii. Environmental Science and Pollution Research. 2020; 28 (9):11528-11539.

Chicago/Turabian Style

Fernanda Brêda-Alves; Valéria De Oliveira Fernandes; Micheline Kézia Cordeiro-Araújo; Mathias Ahii Chia. 2020. "The combined effect of clethodim (herbicide) and nitrogen variation on allelopathic interactions between Microcystis aeruginosa and Raphidiopsis raciborskii." Environmental Science and Pollution Research 28, no. 9: 11528-11539.

Article
Published: 10 July 2020 in Environmental Biology of Fishes
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The aquatic ecosystem is the ultimate sink for consumer and industrial waste discharge that contains nanometals such as titanium dioxide nanoparticle (n-TiO2). In this environment, nutrient availability and nanometals influence phytoplankton community structure and function. In a mesocosm experiment, we evaluated the interactive effect of n-TiO2 (48 mg L−1) and two nitrogen (N) levels (limited, LN; and replete, HN) on the phytoplankton community structure (biomass, species diversity and richness, algal species divisions), biochemical composition (carbohydrates, proteins, and lipids), and antioxidant response (peroxidase activity, POD). n-TiO2 decreased total phytoplankton biomass, and its combination with HN led to the highest decrease. Species diversity was not affected by N level, n-TiO2, and their interaction, while species richness decreased in combined n-TiO2 and HN treatment. All these recorded effects of n-TiO2 on the phytoplankton community structure were enhanced by increasing temperature over time. LN initially reduced phytoplankton carbohydrate content but increased by the presence of n-TiO2 and its interaction with N levels. Total protein and lipid content were not affected by n-TiO2 or its interaction with N levels. POD activity was increased by the interaction between n-TiO2 and the N levels tested. Our results indicate that the influence of n-TiO2 on the phytoplankton community was dependent on the concentration of N. Also, phytoplankton carbohydrate content and community structure varied with increasing water temperature. A few species thrived concerning biomass during exposure to the LN + n-TiO2 (Scenedesmus quadricauda, Coelastrum reticulum, and Microcystis sp.) and HN + n-TiO2 (Microcystis sp.) treatments. Members of the Chlorophyta were generally susceptible to the presence of n-TiO2 regardless of the N level. Thus, the presence of n-TiO2 in aquatic ecosystems can alter phytoplankton community structure and dynamics.

ACS Style

Suleiman Dauda; Ayene Martha Gabriel; Onozasi Firdaws Idris; Mathias Ahii Chia. Combined nanoTiO2 and nitrogen effects on phytoplankton: a mesocosm approach. Environmental Biology of Fishes 2020, 32, 3123 -3132.

AMA Style

Suleiman Dauda, Ayene Martha Gabriel, Onozasi Firdaws Idris, Mathias Ahii Chia. Combined nanoTiO2 and nitrogen effects on phytoplankton: a mesocosm approach. Environmental Biology of Fishes. 2020; 32 (5):3123-3132.

Chicago/Turabian Style

Suleiman Dauda; Ayene Martha Gabriel; Onozasi Firdaws Idris; Mathias Ahii Chia. 2020. "Combined nanoTiO2 and nitrogen effects on phytoplankton: a mesocosm approach." Environmental Biology of Fishes 32, no. 5: 3123-3132.

Research article
Published: 26 June 2020 in Environmental Science and Pollution Research
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Microcystins (MCs) are the most studied toxins of cyanobacteria in freshwater bodies worldwide. However, they are poorly documented in coastal waters in several parts of the world. In this study, we investigated the composition of cyanobacteria and the presence of microcystins (MCs) in several coastal aquatic ecosystems of Nigeria. Direct morphological analysis revealed that members of the genus Oscillatoria were dominant with five species, followed by Trichodesmium with two species in Nigerian coastal waters. Oso Ibanilo had the highest cyanobacterial biomass (998 × 103 cells/L), followed by Rivers Ocean (156 × 103 cells/L). Except for the Cross River Ocean, cyanobacteria were present in all the investigated aquatic ecosystems. Ten (10) out of twenty water bodies examined had detectable levels of MCs. Furthermore, genomic DNA analysis for the mcyE gene of microcystin synthetase (mcy) cluster showed identities higher than 86% (query coverage > 96%) with toxic strains of cyanobacteria in all the samples analyzed. Also, the sequences of samples matched those of uncultured cyanobacteria from recreational lakes in Southern Germany. Our findings indicate that the presence of toxic cyanobacteria in coastal waters of Nigeria is of public and environmental health concern.

ACS Style

Medina O Kadiri; Solomon Isagba; Jeffrey U Ogbebor; Osasere A. Omoruyi; Timothy E. Unusiotame-Owolagba; Adriana Sturion Lorenzi; Maria Do Carmo Bittencourt-Oliveira; Mathias Ahii Chia. The presence of microcystins in the coastal waters of Nigeria, from the Bights of Bonny and Benin, Gulf of Guinea. Environmental Science and Pollution Research 2020, 27, 1 -10.

AMA Style

Medina O Kadiri, Solomon Isagba, Jeffrey U Ogbebor, Osasere A. Omoruyi, Timothy E. Unusiotame-Owolagba, Adriana Sturion Lorenzi, Maria Do Carmo Bittencourt-Oliveira, Mathias Ahii Chia. The presence of microcystins in the coastal waters of Nigeria, from the Bights of Bonny and Benin, Gulf of Guinea. Environmental Science and Pollution Research. 2020; 27 (28):1-10.

Chicago/Turabian Style

Medina O Kadiri; Solomon Isagba; Jeffrey U Ogbebor; Osasere A. Omoruyi; Timothy E. Unusiotame-Owolagba; Adriana Sturion Lorenzi; Maria Do Carmo Bittencourt-Oliveira; Mathias Ahii Chia. 2020. "The presence of microcystins in the coastal waters of Nigeria, from the Bights of Bonny and Benin, Gulf of Guinea." Environmental Science and Pollution Research 27, no. 28: 1-10.

Journal article
Published: 06 November 2019 in Chemosphere
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Increased agricultural intensification goes with the widespread use of herbicides that adversely affect aquatic biodiversity. The effects of herbicides on toxin-producing cyanobacteria have been poorly studied. The present study aimed to investigate the toxicological and physiological effects of the herbicide clethodim on Raphidiopsis raciborskii (a.k.a. Cylindrospermopsis raciborskii) ITEPA1 and Microcystis aeruginosa BCCUSP232. On day four of the experiment, the exposure to 25 mg/L clethodim resulted in the highest cell density of R. raciborskii. Similarly, exposure to the 1, 5, 20, and 50 mg/L clethodim treatments resulted in the highest cell densities of M. aeruginosa on day 4 of the experiment. Medium effect concentrations (EC50) after 96 h of exposure of both strains to clethodim were 192.98 mg/L and 168.73 mg/L for R. raciborskii and M. aeruginosa, respectively. The presence of clethodim significantly increased the total microcystin content of M. aeruginosa compared to the control cultures. At 400 mg/L, total saxitoxins content of R. raciborskii was 27% higher than that of the control cultures on day 4. In contrast, cultures exposed to 100 mg/L clethodim had the lowest saxitoxins levels per cell quota. There was an increase in the levels of intracellular hydrogen peroxide in both species during exposure to clethodim, which was followed by significant changes (p < 0.05) in the activity of antioxidant enzymes such as peroxidase and superoxide dismutase. These results revealed that the presence of low levels of clethodim in the aquatic environment might lead to the excessive proliferation of cyanobacteria and alteration of their cyanotoxins content.

ACS Style

Fernanda Brêda-Alves; Frederico Pacheco Militão; Brener Freitas de Alvarenga; Pamela Ferreira Miranda; Valéria De Oliveira Fernandes; Micheline Kézia Cordeiro-Araújo; Mathias Ahii Chia. Clethodim (herbicide) alters the growth and toxins content of Microcystis aeruginosa and Raphidiopsis raciborskii. Chemosphere 2019, 243, 125318 .

AMA Style

Fernanda Brêda-Alves, Frederico Pacheco Militão, Brener Freitas de Alvarenga, Pamela Ferreira Miranda, Valéria De Oliveira Fernandes, Micheline Kézia Cordeiro-Araújo, Mathias Ahii Chia. Clethodim (herbicide) alters the growth and toxins content of Microcystis aeruginosa and Raphidiopsis raciborskii. Chemosphere. 2019; 243 ():125318.

Chicago/Turabian Style

Fernanda Brêda-Alves; Frederico Pacheco Militão; Brener Freitas de Alvarenga; Pamela Ferreira Miranda; Valéria De Oliveira Fernandes; Micheline Kézia Cordeiro-Araújo; Mathias Ahii Chia. 2019. "Clethodim (herbicide) alters the growth and toxins content of Microcystis aeruginosa and Raphidiopsis raciborskii." Chemosphere 243, no. : 125318.

Article
Published: 15 August 2019 in Environmental Monitoring and Assessment
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Microcystins (MCs) are toxic secondary metabolites produced by several cyanobacteria genera that have been implicated in human cancer cases and deaths. Human exposure routes include direct contact with contaminated water and the consumption of contaminated food. The present study investigated the presence of MCs in three commonly consumed vegetables at the point of sale in market places as a means of assessing the direct human health risk of buying vegetables. Overall, 53% of the vegetables obtained from different markets had levels of MCs that were higher than 1.00 μg/g. Amaranthus hybridus L. (smooth amaranth) had the highest MC concentration (4.79 μg/g) in samples obtained from Sabon Gari Market, while Lactuca sativa L. (garden lettuce) had the lowest concentration (0.17 μg/g) in samples obtained from Dan-Magaji Market. The highest total daily intake (TDI) of MCs by an adult weighing 60 kg was 3.19 μg/kg for A. hybridus, 1.41 μg/kg for Brassica oleracea L. (cabbage), and 2.94 μg/kg for L. sativa. The highest TDI of MCs for a child weighing 25 kg was highest in A. hybridus (1.91 μg/kg), followed by L. sativa (1.77 μg/kg). These results revealed that the consumption of vegetables sold in markets in Zaria, Nigeria, during the dry season represents a major exposure route to MCs. There is, therefore, an urgent need to develop policies and monitoring strategies to tackle this problem in developing countries.

ACS Style

Mathias Ahii Chia; Zinariya Zippora Auta; Akolo Elijah Esson; Abraham G. Yisa; David S. Abolude. Assessment of microcystin contamination of Amaranthus hybridus, Brassica oleracea, and Lactuca sativa sold in markets: a case study of Zaria, Nigeria. Environmental Monitoring and Assessment 2019, 191, 1 -9.

AMA Style

Mathias Ahii Chia, Zinariya Zippora Auta, Akolo Elijah Esson, Abraham G. Yisa, David S. Abolude. Assessment of microcystin contamination of Amaranthus hybridus, Brassica oleracea, and Lactuca sativa sold in markets: a case study of Zaria, Nigeria. Environmental Monitoring and Assessment. 2019; 191 (9):1-9.

Chicago/Turabian Style

Mathias Ahii Chia; Zinariya Zippora Auta; Akolo Elijah Esson; Abraham G. Yisa; David S. Abolude. 2019. "Assessment of microcystin contamination of Amaranthus hybridus, Brassica oleracea, and Lactuca sativa sold in markets: a case study of Zaria, Nigeria." Environmental Monitoring and Assessment 191, no. 9: 1-9.

Journal article
Published: 15 January 2019 in Toxins
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Globally, eutrophication and warming of aquatic ecosystems has increased the frequency and intensity of cyanobacterial blooms and their associated toxins, with the simultaneous detection of multiple cyanotoxins often occurring. Despite the co-occurrence of cyanotoxins such as microcystins and anatoxin-a (ATX) in water bodies, their effects on phytoplankton communities are poorly understood. The individual and combined effects of microcystin-LR (MC-LR) and ATX on the cyanobacteria Microcystis spp., and Anabaena variabilis (a.k.a. Trichormus variabilis), and the chlorophyte, Selenastrum capricornutum were investigated in the present study. Cell density, chlorophyll-a content, and the maximum quantum efficiency of photosystem II (Fv/Fm) of Microcystis cells were generally lowered after exposure to ATX or MC-LR, while the combined treatment with MC-LR and ATX synergistically reduced the chlorophyll-a concentration of Microcystis strain LE-3. Intracellular levels of microcystin in Microcystis LE-3 significantly increased following exposure to MC-LR + ATX. The maximum quantum efficiency of photosystem II of Anabaena strain UTEX B377 declined during exposure to the cyanotoxins. Nitrogen fixation by Anabaena UTEX B377 was significantly inhibited by exposure to ATX, but was unaffected by MC-LR. In contrast, the combination of both cyanotoxins (MC-LR + ATX) caused a synergistic increase in the growth of S. capricornutum. While the toxins caused an increase in the activity of enzymes that scavenge reactive oxygen species in cyanobacteria, enzyme activity was unchanged or decreased in S. capricornutum. Collectively this study demonstrates that MC-LR and ATX can selectively promote and inhibit the growth and performance of green algae and cyanobacteria, respectively, and that the combined effect of these cyanotoxins was often more intense than their individual effects on some strains. This suggests that the release of multiple cyanotoxins in aquatic ecosystems, following the collapse of blooms, may influence the succession of plankton communities.

ACS Style

Mathias Ahii Chia; Benjamin J. Kramer; Jennifer G. Jankowiak; Maria Do Carmo Bittencourt-Oliveira; Christopher J. Gobler. The Individual and Combined Effects of the Cyanotoxins, Anatoxin-a and Microcystin-LR, on the Growth, Toxin Production, and Nitrogen Fixation of Prokaryotic and Eukaryotic Algae. Toxins 2019, 11, 43 .

AMA Style

Mathias Ahii Chia, Benjamin J. Kramer, Jennifer G. Jankowiak, Maria Do Carmo Bittencourt-Oliveira, Christopher J. Gobler. The Individual and Combined Effects of the Cyanotoxins, Anatoxin-a and Microcystin-LR, on the Growth, Toxin Production, and Nitrogen Fixation of Prokaryotic and Eukaryotic Algae. Toxins. 2019; 11 (1):43.

Chicago/Turabian Style

Mathias Ahii Chia; Benjamin J. Kramer; Jennifer G. Jankowiak; Maria Do Carmo Bittencourt-Oliveira; Christopher J. Gobler. 2019. "The Individual and Combined Effects of the Cyanotoxins, Anatoxin-a and Microcystin-LR, on the Growth, Toxin Production, and Nitrogen Fixation of Prokaryotic and Eukaryotic Algae." Toxins 11, no. 1: 43.

Original article
Published: 27 August 2018 in Environmental Earth Sciences
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Changing global climatic conditions and the continuous eutrophication of aquatic ecosystems have led to increased frequency, duration and toxicity of cyanobacterial blooms worldwide. This makes the provision of time series information on cyanotoxins extremely crucial for effective monitoring and management of water resources. The objective of the present study was to investigate seasonal and annual changes in microcystins (MCs), cylindrospermopsins (CYNs), saxitoxins (STXs), neo-saxitoxin (neo-STX) and anatoxin-a (ATX-a) concentrations in 11 public water supply reservoirs in the semiarid region of Brazil, from 2004 to 2011. Per time, at least one cyanotoxin was present in all the investigated reservoirs. High levels of MCs, CYNs, STXs and Neo-STX were detected simultaneously in Carpina, Duas Unas, Ipojuca, and Jucazinho reservoirs. All the investigated reservoirs had significant concentrations of MCs. The highest levels of MCs were found in Carpina (303,300.0 ng g−1) and Duas Unas (122,053.9 ng g−1) reservoirs, while the lowest concentration of the hepatotoxins was recorded in Ipojuca (10.3 ng g−1) reservoir. On the other hand, CYN was detected in four reservoirs, STXs and Neo-STX in ten reservoirs and ATX-a in two reservoirs. The first record of CYN in Carpina reservoir was obtained in 2006. In addition, Carpina reservoir had the highest concentration of STXs and Neo-STX in the dry and rainy seasons, respectively. The high concentration of cyanotoxins observed in most samples obtained from semiarid reservoirs in Brazil demonstrates the need for regular monitoring and updated management programs.

ACS Style

Adriana Sturion Lorenzi; Micheline Kézia Cordeiro-Araújo; Mathias Ahii Chia; Maria Do Carmo Bittencourt-Oliveira. Cyanotoxin contamination of semiarid drinking water supply reservoirs. Environmental Earth Sciences 2018, 77, 595 .

AMA Style

Adriana Sturion Lorenzi, Micheline Kézia Cordeiro-Araújo, Mathias Ahii Chia, Maria Do Carmo Bittencourt-Oliveira. Cyanotoxin contamination of semiarid drinking water supply reservoirs. Environmental Earth Sciences. 2018; 77 (16):595.

Chicago/Turabian Style

Adriana Sturion Lorenzi; Micheline Kézia Cordeiro-Araújo; Mathias Ahii Chia; Maria Do Carmo Bittencourt-Oliveira. 2018. "Cyanotoxin contamination of semiarid drinking water supply reservoirs." Environmental Earth Sciences 77, no. 16: 595.

Journal article
Published: 01 April 2018 in Harmful Algae
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Microcystis and Anabaena (Dolichospermum) are among the most toxic cyanobacterial genera and often succeed each other during harmful algal blooms. The role allelopathy plays in the succession of these genera is not fully understood. The allelopathic interactions of six strains of Microcystis and Anabaena under different nutrient conditions in co-culture and in culture-filtrate experiments were investigated. Microcystis strains significantly reduced the growth of Anabaena strains in mixed cultures with direct cell-to-cell contact and high nutrient levels. Cell-free filtrate from Microcystis cultures proved equally potent in suppressing the growth of nutrient replete Anabaena cultures while also significantly reducing anatoxin-a production. Allelopathic interactions between Microcystis and Anabaena were, however, partly dependent on ambient nutrient levels. Anabaena dominated under low N conditions and Microcystis dominated under nutrient replete and low P during which allelochemicals caused the complete suppression of nitrogen fixation by Anabaena and stimulated glutathione S-transferase activity. The microcystin content of Microcystis was lowered with decreasing N and the presence of Anabaena decreased it further under low P and high nutrient conditions. Collectively, these results indicate that strong allelopathic interactions between Microcystis and Anabaena are closely intertwined with the availability of nutrients and that allelopathy may contribute to the succession, nitrogen availability, and toxicity of cyanobacterial blooms.

ACS Style

Mathias A. Chia; Jennifer G. Jankowiak; Benjamin J. Kramer; Jennifer A. Goleski; I-Shuo```` Huang; Paul Zimba; Maria Do Carmo Bittencourt-Oliveira; Christopher J. Gobler. Succession and toxicity of Microcystis and Anabaena ( Dolichospermum ) blooms are controlled by nutrient-dependent allelopathic interactions. Harmful Algae 2018, 74, 67 -77.

AMA Style

Mathias A. Chia, Jennifer G. Jankowiak, Benjamin J. Kramer, Jennifer A. Goleski, I-Shuo```` Huang, Paul Zimba, Maria Do Carmo Bittencourt-Oliveira, Christopher J. Gobler. Succession and toxicity of Microcystis and Anabaena ( Dolichospermum ) blooms are controlled by nutrient-dependent allelopathic interactions. Harmful Algae. 2018; 74 ():67-77.

Chicago/Turabian Style

Mathias A. Chia; Jennifer G. Jankowiak; Benjamin J. Kramer; Jennifer A. Goleski; I-Shuo```` Huang; Paul Zimba; Maria Do Carmo Bittencourt-Oliveira; Christopher J. Gobler. 2018. "Succession and toxicity of Microcystis and Anabaena ( Dolichospermum ) blooms are controlled by nutrient-dependent allelopathic interactions." Harmful Algae 74, no. : 67-77.

Journal article
Published: 01 January 2018 in Harmful Algae
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Zooplankton are important biocontrol agents for algal blooms in temperate lakes, while their potential in tropical and subtropical environments is not well understood. The aim of the present study was to evaluate the influence of increased zooplankton biomass on phytoplankton community and cyanotoxins (microcystins and saxitoxin) content of a tropical reservoir (Ipojuca reservoir, Brazil) using in situ mesocosms. Mesocosms consisted of 50L transparent polyethylene bags suspended in the reservoir for twelve days. Phytoplankton populations were exposed to treatments having 1 (control), 2, 3 and 4 times the biomass of zooplankton found in the reservoir at the beginning of the experiment. Filamentous cyanobacteria such as Planktothrix agardhii and Cylindrospermopsis raciborskii were not negatively influenced by increasing zooplankton biomass. In contrast, the treatments with 3 and 4 times zooplankton biomass negatively affected the cyanobacteria Aphanocapsa sp., Chroococcus sp., Dolichospermum sp., Merismopedia tenuissima, Microcystis aeruginosa and Pseudanabaena sp.; the diatom Cyclotella meneghiniana; and the cryptophyte Cryptomonas sp. Total microcystin concentration both increased and decreased at different times depending on zooplankton treatment, while saxitoxin level was not significantly different between the treatments and control. The results of the present study suggest that zooplankton biomass can be manipulated to control the excessive proliferation of non-filamentous bloom forming cyanobacteria (e.g. M. aeruginosa) and their associated cyanotoxins.

ACS Style

Juliana Dos Santos Severiano; Viviane Lúcia Dos Santos Almeida-Melo; Maria Do Carmo Bittencourt-Oliveira; Mathias Chia; Ariadne Do Nascimento Moura. Effects of increased zooplankton biomass on phytoplankton and cyanotoxins: A tropical mesocosm study. Harmful Algae 2018, 71, 10 -18.

AMA Style

Juliana Dos Santos Severiano, Viviane Lúcia Dos Santos Almeida-Melo, Maria Do Carmo Bittencourt-Oliveira, Mathias Chia, Ariadne Do Nascimento Moura. Effects of increased zooplankton biomass on phytoplankton and cyanotoxins: A tropical mesocosm study. Harmful Algae. 2018; 71 ():10-18.

Chicago/Turabian Style

Juliana Dos Santos Severiano; Viviane Lúcia Dos Santos Almeida-Melo; Maria Do Carmo Bittencourt-Oliveira; Mathias Chia; Ariadne Do Nascimento Moura. 2018. "Effects of increased zooplankton biomass on phytoplankton and cyanotoxins: A tropical mesocosm study." Harmful Algae 71, no. : 10-18.

Journal article
Published: 01 December 2017 in Science of The Total Environment
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The eutrophication of aquatic ecosystems is a serious environmental problem that leads to increased frequency of cyanobacterial blooms and concentrations of cyanotoxins. These changes in aquatic chemistry can negatively affect animal and human health. Environment-friendly methods are needed to control bloom forming cyanobacteria. We investigated the effect of Hordeum vulgare L. (barley) straw degradation extract and its fractions on the growth, oxidative stress, antioxidant enzyme activities, and microcystins content of Microcystis aeruginosa (Kützing) Kützing BCCUSP232. Exposure to the extract significantly (p<0.05) inhibited the growth of M. aeruginosa throughout the study, whereas only the highest concentration of fractions 1 and 2 significantly (p<0.05) reduced the growth of the cyanobacterium on day 10 of the experiment. The production of reactive oxygen species (ROS), lipid peroxidation and antioxidant enzyme activities were significantly (p<0.05) altered by the extract and fractions 1 and 2. Phytochemical profiling of the extract and its fractions revealed that the barley straw degradation process yielded predominantly phenolic acids. These results demonstrate that barley straw extract and its fractions can efficiently interfere with the growth and development of M. aeruginosa under laboratory conditions.

ACS Style

Gustavo Mecina; Anne Dokkedal; Luiz Leonardo Saldanha; Mathias Chia; Micheline Kézia Cordeiro-Araújo; Maria Do Carmo Bittencourt-Oliveira; Regildo Márcio Gonçalves da Silva. Response of Microcystis aeruginosa BCCUSP 232 to barley (Hordeum vulgare L.) straw degradation extract and fractions. Science of The Total Environment 2017, 599-600, 1837 -1847.

AMA Style

Gustavo Mecina, Anne Dokkedal, Luiz Leonardo Saldanha, Mathias Chia, Micheline Kézia Cordeiro-Araújo, Maria Do Carmo Bittencourt-Oliveira, Regildo Márcio Gonçalves da Silva. Response of Microcystis aeruginosa BCCUSP 232 to barley (Hordeum vulgare L.) straw degradation extract and fractions. Science of The Total Environment. 2017; 599-600 ():1837-1847.

Chicago/Turabian Style

Gustavo Mecina; Anne Dokkedal; Luiz Leonardo Saldanha; Mathias Chia; Micheline Kézia Cordeiro-Araújo; Maria Do Carmo Bittencourt-Oliveira; Regildo Márcio Gonçalves da Silva. 2017. "Response of Microcystis aeruginosa BCCUSP 232 to barley (Hordeum vulgare L.) straw degradation extract and fractions." Science of The Total Environment 599-600, no. : 1837-1847.

Journal article
Published: 01 September 2017 in Harmful Algae
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The cyanobacterial toxin cylindrospermopsin (CYN) has become a globally important secondary metabolite due to the negative effect it has on human and animal health. As a means of evaluating the risk of human exposure to CYN, the bioaccumulation and depuration of the toxin in lettuce (Lactuca sativa L.) and arugula (Eruca sativa Mill.) were investigated, after irrigation with contaminated water. The vegetables were irrigated for 7days with CYN (3, 5 and 10μg/L) contaminated water (bioaccumulation phase), and subsequently, irrigated for 7days with uncontaminated distilled water (depuration phase). In general, the bioaccumulation of CYN in both vegetables decreased with increasing exposure concentration. Bioconcentration factor (BCF) of CYN increased with the progression of the experiment at 3.0μg/L CYN, while the reverse occurred at 5 and 10μg/L CYN. In arugula, BCF increased at all CYN exposure concentrations throughout the study. The depuration of CYN decreased with increasing exposure concentration but was highest in the plants of both species with the highest bioaccumulation of CYN. Specifically, in plants previously irrigated with water contaminated with 3, 5 and 10μg/L CYN, the depuration of the toxin was 60.68, 27.67 and 18.52% for lettuce, and 47, 46.21 and 27.67% for arugula, respectively. Human health risks assessment revealed that the consumption of approximately 10 to 40g of vegetables per meal will expose children and adults to 1.00-6.00ng CYN/kg body mass for lettuce and 2.22-7.70ng CYN/kg body mass for arugula. The irrigation of lettuce and arugula with contaminated water containing low CYN concentrations constitutes a potential human exposure route.

ACS Style

Micheline Kézia Cordeiro-Araújo; Mathias Chia; Maria Do Carmo Bittencourt-Oliveira. Potential human health risk assessment of cylindrospermopsin accumulation and depuration in lettuce and arugula. Harmful Algae 2017, 68, 217 -223.

AMA Style

Micheline Kézia Cordeiro-Araújo, Mathias Chia, Maria Do Carmo Bittencourt-Oliveira. Potential human health risk assessment of cylindrospermopsin accumulation and depuration in lettuce and arugula. Harmful Algae. 2017; 68 ():217-223.

Chicago/Turabian Style

Micheline Kézia Cordeiro-Araújo; Mathias Chia; Maria Do Carmo Bittencourt-Oliveira. 2017. "Potential human health risk assessment of cylindrospermopsin accumulation and depuration in lettuce and arugula." Harmful Algae 68, no. : 217-223.

Journal article
Published: 01 August 2017 in Ecotoxicology and Environmental Safety
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Growing evidence suggests that some bioactive metabolites (e.g. cyanotoxins) produced by cyanobacteria have allelopathic potential, due to their inhibitory or stimulatory effects on competing species. Although a number of studies have shown that the cyanotoxin cylindrospermopsin (CYN) has variable effects on phytoplankton species, the impact of changing physicochemical conditions on its allelopathic potential is yet to be investigated. We investigated the physiological response of Microcystis aeruginosa (Cyanobacteria) and Acutodesmus acuminatus (Chlorophyta) to CYN under varying nitrogen and light conditions. At 24h, higher microcystins content of M. aeruginosa was recorded under limited light in the presence of CYN, while at 120h the lower levels of the toxins were observed in the presence of CYN under optimum light. Total MCs concentration was significantly (p0.05) changes in total MCs concentrations after exposure to CYN under high nitrogen conditions. As expected, limited light and limited nitrogen conditions resulted in lower cell density of both species, while CYN only significantly (p<0.05) inhibited the growth of M. aeruginosa. Regardless of the light or nitrogen condition, the presence of CYN increased internal HO content of both species, which resulted in significant (p<0.05) changes in antioxidant enzyme (catalase, peroxidase, superoxide dismutase and glutathione S-transferase) activities. The oxidative stress caused by CYN was higher under limited light and limited nitrogen. These results showed that M. aeruginosa and A. acuminatus have variable response to CYN under changing light and nitrogen conditions, and demonstrate that need to consider changes in physicochemical conditions during ecotoxicological and ecophysiological investigations.

ACS Style

Mathias Chia; Micheline Kézia Cordeiro-Araújo; Adriana Sturion Lorenzi; Maria Do Carmo Bittencourt-Oliveira. Cylindrospermopsin induced changes in growth, toxin production and antioxidant response of Acutodesmus acuminatus and Microcystis aeruginosa under differing light and nitrogen conditions. Ecotoxicology and Environmental Safety 2017, 142, 189 -199.

AMA Style

Mathias Chia, Micheline Kézia Cordeiro-Araújo, Adriana Sturion Lorenzi, Maria Do Carmo Bittencourt-Oliveira. Cylindrospermopsin induced changes in growth, toxin production and antioxidant response of Acutodesmus acuminatus and Microcystis aeruginosa under differing light and nitrogen conditions. Ecotoxicology and Environmental Safety. 2017; 142 ():189-199.

Chicago/Turabian Style

Mathias Chia; Micheline Kézia Cordeiro-Araújo; Adriana Sturion Lorenzi; Maria Do Carmo Bittencourt-Oliveira. 2017. "Cylindrospermopsin induced changes in growth, toxin production and antioxidant response of Acutodesmus acuminatus and Microcystis aeruginosa under differing light and nitrogen conditions." Ecotoxicology and Environmental Safety 142, no. : 189-199.

Journal article
Published: 01 June 2017 in Aquatic Toxicology
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The broad application of titanium dioxide nanoparticles (n-TiO) in many consumer products has resulted in the release of substantial quantities into aquatic systems. While n-TiO have been shown to induce some unexpected toxic effects on aquatic organisms such as microalgae, the influence of changing nutrient conditions on the toxicity of the metal has not been investigated. We evaluated the toxicity of n-TiO to Chlorella vulgaris under varying nitrogen conditions. Limited nitrogen (2.2μM) decreased growth and biomass (dry weight and pigment content), while lipid peroxidation (malondialdehyde content), glutathione S-transferase activity (GST) and peroxidase (POD) activity were increased. Similarly, exposure to n-TiO under replete nitrogen condition resulted in a general decrease in growth and biomass, while GST and POD activities were significantly increased. The combination of limited nitrogen with n-TiO exposure further decreased growth and biomass, and increased GST and POD activities of the microalga. These results suggest that in addition to the individual effects of each investigated condition, nitrogen limitation makes C. vulgaris more susceptible to the effects of n-TiO with regard to some physiological parameters. This implies that the exposure of C. vulgaris and possibly other green algae to this nanoparticle under limited or low nitrogen conditions may negatively affect their contribution to primary production in oligotrophic aquatic ecosystems.

ACS Style

Suleiman Dauda; Mathias Ahii Chia; Sunday Paul Bako. Toxicity of titanium dioxide nanoparticles to Chlorella vulgaris Beyerinck (Beijerinck) 1890 (Trebouxiophyceae, Chlorophyta) under changing nitrogen conditions. Aquatic Toxicology 2017, 187, 108 -114.

AMA Style

Suleiman Dauda, Mathias Ahii Chia, Sunday Paul Bako. Toxicity of titanium dioxide nanoparticles to Chlorella vulgaris Beyerinck (Beijerinck) 1890 (Trebouxiophyceae, Chlorophyta) under changing nitrogen conditions. Aquatic Toxicology. 2017; 187 ():108-114.

Chicago/Turabian Style

Suleiman Dauda; Mathias Ahii Chia; Sunday Paul Bako. 2017. "Toxicity of titanium dioxide nanoparticles to Chlorella vulgaris Beyerinck (Beijerinck) 1890 (Trebouxiophyceae, Chlorophyta) under changing nitrogen conditions." Aquatic Toxicology 187, no. : 108-114.