scholarly journals Importance of strain type to predict the toxicological risk associated with Microcystis aeruginosa blooms: comparison of Microtox® analysis and immunoassay

2012 ◽  
Vol 10 (2) ◽  
pp. 256-261 ◽  
Author(s):  
A. D'ors ◽  
M. C. Bartolomé ◽  
S. Sánchez-Fortún
Keyword(s):  
Microcystis Aeruginosa ◽  
Potential Risk ◽  
Cyanobacterial Blooms ◽  
Aquatic Environments ◽  
Preliminary Screening ◽  
Microcystin Concentration ◽  
Bioluminescence Assay ◽  
Strain Type ◽  
Toxicological Risk

The occurrence of toxic cyanobacterial blooms in aquatic environments, associated with human health problems and animal deaths, has increased the need for rapid, reliable and sensitive methods to determine the toxicity of microcystin produced by cyanobacteria. An in vitro Microtox® system and a commercially available microcystin ELISA were used to screen out the potential risk associated with selected Microcystis aeruginosa strains (Ma1D–Ma8D). Results showed the existence of three differentiated groups in the selected M. aeruginosa strains. Strains Ma7D and Ma6D were determined to be very toxic, strains Ma2D, Ma1D and Ma5D as moderately toxic and strains Ma8D, Ma4D and MA3D as non-toxic. These results agreed with the microcystin concentration values obtained by immunoassay. Although the data obtained by other authors clearly show that Microtox® is not sensitive to microcystins, our results suggested that this bioluminescence assay may prove useful in the preliminary screening of cyanobacterial blooms for microcystin-based toxicity. Additionally, the combination of immunodetection and toxicity-based Microtox® provides a useful addition to the methods already available for detection of cyanobacterial toxins.

Environmental factors associated with a toxic bloom of Microcystis aeruginosa

2000 ◽  
Vol 57 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Jean M Jacoby ◽  
Diane C Collier ◽  
Eugene B Welch ◽  
F Joan Hardy ◽  
Michele Crayton
Keyword(s):  
Environmental Factors ◽  
Microcystis Aeruginosa ◽  
Toxin Production ◽  
Water Transparency ◽  
Cyanobacterial Blooms ◽  
Zooplankton Abundance ◽  
Factors Associated ◽  
Water Column Stability ◽  
Microcystin Concentration ◽  
Toxic Bloom

Environmental factors associated with the occurrence of toxic cyanobacterial blooms and toxin production were investigated during the summers of 1994 and 1995 in Steilacoom Lake, Washington. A pronounced and prolonged toxic bloom of Microcystis aeruginosa occurred during summer 1994 but not during 1995. Lake characteristics that were associated with the toxic bloom in 1994 were higher total phosphorus, decreased water transparency, high water column stability, high surface water temperature and pH, and decreased lake flushing. Decreased water transparency during 1994 may have been due to significantly lower zooplankton abundance. We hypothesize that this decreased transparency was caused by increased planktivory by higher numbers of coho salmon (Oncorhynchus kisutch) fingerlings during 1994 and (or) inhibition of zooplankton grazing by Microcystis. The success of Microcystis over other cyanobacteria was associated with low nitrogen to phosphorus ratios and low nitrate-nitrogen with sufficient ammonium-nitrogen concentrations. Toxin production (i.e., micrograms of microcystin per gram of plankton biomass) was not constant over the duration of detectable toxicity; hence, no relationship was found between Microcystis abundance and microcystin concentration. However, microcystin concentration was positively correlated with increasing soluble reactive phosphorus concentrations between 1 and 10 µg·L-1, indicating that toxin production may have been limited by phosphorus.

scholarly journals Chemical Characterization of Microcystis aeruginosa for Feed and Energy Uses

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3013
Author(s):  
Larissa Souza Passos ◽  
Éryka Costa Almeida ◽  
Claudio Martin Pereira de Pereira ◽  
Alessandro Alberto Casazza ◽  
Attilio Converti ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Animal Feed ◽  
Renewable Energy Sources ◽  
Chemical Characterization ◽  
Cyanobacterial Blooms ◽  
Energy Sources ◽  
Carbohydrate Source ◽  
Heating Value ◽  
Adverse Health Effects ◽  
Degradation Reactions

Cyanobacterial blooms and strains absorb carbon dioxide, drawing attention to its use as feed for animals and renewable energy sources. However, cyanobacteria can produce toxins and have a low heating value. Herein, we studied a cyanobacterial strain harvested during a bloom event and analyzed it to use as animal feed and a source of energy supply. The thermal properties and the contents of total nitrogen, protein, carbohydrate, fatty acids, lipid, and the presence of cyanotoxins were investigated in the Microcystis aeruginosa LTPNA 01 strain and in a bloom material. Microcystins (hepatotoxins) were not detected in this strain nor in the bloom material by liquid chromatography coupled to mass spectrometry. Thermogravimetric analysis showed that degradation reactions (devolatilization) initiated at around 180 °C, dropping from approximately 90% to 20% of the samples’ mass. Our work showed that despite presenting a low heating value, both biomass and non-toxic M. aeruginosa LTPNA 01 could be used as energy sources either by burning or producing biofuels. Both can be considered a protein and carbohydrate source similar to some microalgae species as well as biomass fuel. It could also be used as additive for animal feed; however, its safety and potential adverse health effects should be further investigated.

scholarly journals A Brief Review of the Structure, Cytotoxicity, Synthesis, and Biodegradation of Microcystins

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2147
Author(s):  
Anjali Krishnan ◽  
Xiaozhen Mou
Keyword(s):  
Health Hazard ◽  
Aquatic Organisms ◽  
Water Soluble ◽  
Cyanobacterial Blooms ◽  
Aquatic Environments ◽  
Natural Environments ◽  
Exposure Pathway ◽  
Environmental Transformation ◽  
Cyclic Heptapeptide ◽  
Harmful Cyanobacterial Blooms

Harmful cyanobacterial blooms pose an environmental health hazard due to the release of water-soluble cyanotoxins. One of the most prevalent cyanotoxins in nature is microcystins (MCs), a class of cyclic heptapeptide hepatotoxins, and they are produced by several common cyanobacteria in aquatic environments. Once released from cyanobacterial cells, MCs are subjected to physical chemical and biological transformations in natural environments. MCs can also be taken up and accumulated in aquatic organisms and their grazers/predators and induce toxic effects in several organisms, including humans. This brief review aimed to summarize our current understanding on the chemical structure, exposure pathway, cytotoxicity, biosynthesis, and environmental transformation of microcystins.

scholarly journals Evidence of Quorum Sensing in Cyanobacteria by Homoserine Lactones: The Origin of Blooms

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1831
Author(s):  
Natalia Herrera ◽  
Fernando Echeverri
Keyword(s):  
Cell Proliferation ◽  
Quorum Sensing ◽  
Microcystis Aeruginosa ◽  
Industrial Effluents ◽  
Cyanobacterial Blooms ◽  
Cylindrospermopsis Raciborskii ◽  
Bacterial Communication ◽  
Homoserine Lactones ◽  
Exogenous Compounds ◽  
Almost All

Although several theories have been postulated to explain cyanobacterial blooms, their biochemical origin has not yet been found. In this work, we explore the existence of bacterial communication, called quorum sensing, in Microcystis aeruginosa and Cylindrospermopsis raciborskii. Thus, the application of several known acylhomoserine lactones to cultures of both cyanobacteria causes profound metabolic. At 72 h post-application, some of them produced substantial increases in cell proliferation, while others were inhibitors. There was a correlation with colony-forming activity for most of them. According to ELISA analysis, the microcystin levels were increased with some lactones. However, there was a clear difference between M. aeruginosa and C. raciborskii culture since, in the first one, there was an inducing effect on cell proliferation, while in C. raciborskii, the effects were minor. Besides, there were compound inhibitors and inducers of microcystins production in M. aeruginosa, but almost all compounds were only inducers of saxitoxin production in C. raciborskii. Moreover, each lactone appears to be involved in a specific quorum sensing process. From these results, the formation of cyanobacterial blooms in dams and reservoirs could be explained since lactones may come from cyanobacteria and other sources as bacterial microflora-associated or exogenous compounds structurally unrelated to lactones, such as drugs, industrial effluents, and agrochemicals.

scholarly journals Formulation and in-vitro preliminary screening of polyphyto antilithiatic combination

2013 ◽  
Vol 2 (3) ◽  
pp. 214-217
Author(s):  
Abhishek Bharadwaj ◽  
Kumud Upadhayaya ◽  
N.V. Satheesh Madhav
Keyword(s):  
Preliminary Screening

scholarly journals DEVELOPMENT OF IN VITRO METHODOLOGIES FOR INHIBITION OF PATHOGENIC BACTERIA BY POTENTIAL PROBIOTIC LACTOBACILLUS SPS; AN EVIDENCE FOR PRODUCTION OF ANTIMICROBIAL SUBSTANCES

2016 ◽  
Vol 8 (12) ◽  
pp. 277
Author(s):  
Prabhurajeshwar C. ◽  
Kelmani Chandrakanth R.
Keyword(s):  
Bile Salts ◽  
Pathogenic Bacteria ◽  
Antimicrobial Activities ◽  
Local Market ◽  
Preliminary Screening ◽  
Milk Products ◽  
Antimicrobial Substances ◽  
Live Bacteria ◽  
Digestive Health

<p><strong>Objective: </strong>Probiotic products consist of specific strains of live bacteria that have potentially favorable health effects. A number of studies provide evidence that milk products with probiotics may be beneficial for digestive health and may improve various digestive problems. The purpose of the present study was to investigate <em>Lactobacillus</em> species with potential activities isolated from different cheese samples of local market.</p><p><strong>Methods: </strong>A total 42 lactic acid bacteria strains were isolated, fourteen (14/42) best <em>Lactobacillus</em> isolates were selected by preliminary screening as potential probiotics with antimicrobial activity against pathogenic bacteria. All the fourteen <em>Lactobacillus</em> isolates were then characterized <em>in vitro</em> for their probiotic features and antimicrobial activities against pathogens.</p><p><strong>Results: </strong>The results noticed that all selected <em>Lactobacillus</em> isolates (CH3, CH4 and CH6) were screened and confirmed as <em>Lactobacillus. </em>The isolates were able to grow at different pH, NaCl and bile salts, also exhibited the best antimicrobial activities against pathogens. All the isolates were susceptible to antibiotics used and isolates were also revealed the noticeable aggregation and hydrophobicity studies.<strong></strong></p><p><strong>Conclusion: </strong>Selected <em>Lactobacillus </em>isolates were considered as ideal, effective probiotic bacteria. Thus, they could be examined further and contribute to preventing and controlling several infections associated with intestine and for human health benefits.</p>

scholarly journals Potential Effects of Corneal Cross-Linking upon the Limbus

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Johnny E. Moore ◽  
Davide Schiroli ◽  
C. B. Tara Moore
Keyword(s):  
Stem Cells ◽  
Potential Risk ◽  
Ocular Surface ◽  
Ex Vivo ◽  
Uv Exposure ◽  
Cross Linking ◽  
Clinical Complications ◽  
Cellular Dna ◽  
Pathological Consequence

Corneal cross-linking is nowadays the most used strategy for the treatment of keratoconus and recently it has been exploited for an increasing number of different corneal pathologies, from other ectatic disorders to keratitis. The safety of this technique has been widely assessed, but clinical complications still occur. The potential effects of cross-linking treatment upon the limbus are incompletely understood; it is important therefore to investigate the effect of UV exposure upon the limbal niche, particularly as UV is known to be mutagenic to cellular DNA and the limbus is where ocular surface tumors can develop. The risk of early induction of ocular surface cancer is undoubtedly rare and has to date not been published other than in one case after cross-linking. Nevertheless it is important to further assess, understand, and reduce where possible any potential risk. The aim of this review is to summarize all the reported cases of a pathological consequence for the limbal cells, possibly induced by cross-linking UV exposure, the studies donein vitroorex vivo, the theoretical bases for the risks due to UV exposure, and which aspects of the clinical treatment may produce higher risk, along with what possible mechanisms could be utilized to protect the limbus and the delicate stem cells present within it.

scholarly journals Using a two-layered sphere model to investigate the impact of gas vacuoles on the inherent optical properties of <i>Microcystis aeruginosa</i>

2013 ◽  
Vol 10 (12) ◽  
pp. 8139-8157 ◽  
Author(s):  
M. W. Matthews ◽  
S. Bernard
Keyword(s):  
Optical Properties ◽  
Microcystis Aeruginosa ◽  
Cyanobacterial Blooms ◽  
Shell Layer ◽  
Sphere Model ◽  
Homogeneous Population ◽  
Chl A ◽  
Inherent Optical Properties ◽  
Gas Vacuoles ◽  
The Impact

Abstract. A two-layered sphere model is used to investigate the impact of gas vacuoles on the inherent optical properties (IOPs) of the cyanophyte Microcystis aeruginosa. Enclosing a vacuole-like particle within a chromatoplasm shell layer significantly altered spectral scattering and increased backscattering. The two-layered sphere model reproduced features in the spectral attenuation and volume scattering function (VSF) that have previously been attributed to gas vacuoles. This suggests the model is good at least as a first approximation for investigating how gas vacuoles alter the IOPs. Measured Rrs was used to provide a range of values for the central value of the real refractive index, 1 + ε, for the shell layer using measured IOPs and a radiative transfer model. Sufficient optical closure was obtained for 1 + ε between 1.1 and 1.14, which had corresponding Chl a-specific phytoplankton backscattering, bbφ*, between 3.9 and 7.2 × 10−3 m2 mg−1 at 510 nm. The bbφ* values are in close agreement with the literature and in situ particulate backscattering measurements. Rrs simulated for a population of vacuolate cells was greatly enlarged relative to a homogeneous population. A sensitivity analysis of empirical algorithms for estimating Chl a in eutrophic/hypertrophic waters suggests these are robust under variable constituent concentrations and likely to be species-sensitive. The study confirms that gas vacuoles cause significant increase in backscattering and are responsible for the high Rrs values observed in buoyant cyanobacterial blooms. Gas vacuoles are therefore one of the most important bio-optical substructures influencing the IOPs in phytoplankton.

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