Publisher Summary This chapter discusses the analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Analyses of the Folin-Ciocalteu (FC) type are convenient, simple, and require only common equipment and have produced a large body of comparable data. Under proper conditions, the assay is inclusive of monophenols and gives predictable reactions with the types of phenols found in nature. Because different phenols react to different degrees, expression of the results as a single number—such as milligrams per liter gallic acid equivalence—is necessarily arbitrary. Because the reaction is independent, quantitative, and predictable, analysis of a mixture of phenols can be recalculated in terms of any other standard. The assay measures all compounds readily oxidizable under the reaction conditions and its very inclusiveness allows certain substances to also react that are either not phenols or seldom thought of as phenols (e.g., proteins). Judicious use of the assay—with consideration of potential interferences in particular samples and prior study if necessary—can lead to very informative results. Aggregate analysis of this type is an important supplement to and often more informative than reems of data difficult to summarize from various techniques, such as high-performance liquid chromatography (HPLC) that separate a large number of individual compounds .The predictable reaction of components in a mixture makes it possible to determine a single reactant by other means and to calculate its contribution to the total FC phenol content. Relative insensitivity of the FC analysis to many adsorbents and precipitants makes differential assay—before and after several different treatments—informative.

Analysis of total phenols and other oxidation substrates and antioxidants by means of folin-ciocalteu reagent

This book describes the present state of knowledge regarding the impact of cyanobacteria on health through the use of water. It considers aspects of risk management and details the information needed for protecting drinking water sources and recreational water bodies from the health hazards caused by cyanobacteria and their toxins. It also outlines the state of knowledge regarding the principal considerations in the design of programmes and studies for monitoring water resources and supplies and describes the approaches and procedures used.
The development of this publication was guided by the recommendations of several expert meetings concerning drinking water (Geneva, December 1995; Bad Elster, June
1996) and recreational water (Bad Elster, June 1996; St Helier, May 1997). An expert meeting in Bad Elster, April 1997, critically reviewed the literature concerning the toxicity of cyanotoxins and developed the scope and content of this book. A draft manuscript was reviewed at an editorial meeting in November 1997, and a further draft was
reviewed by the working group responsible for updating the Guidelines for Drinkingwater Quality in March 1998.

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Toxic cyanobacteria in water: a guide to their public health consequences, monitoring and management.

Cyanobacteria secondary metabolites--the cyanotoxins.

(2002). The Effects of Harmful Algal Blooms on Aquatic Organisms. Reviews in Fisheries Science: Vol. 10, No. 2, pp. 113-390.

The Effects of Harmful Algal Blooms on Aquatic Organisms

Amongst the diverse and potent biological activities of free fatty acids (FFAs) is the ability to kill or inhibit the growth of bacteria. The antibacterial properties of FFAs are used by many organisms to defend against parasitic or pathogenic bacteria. Whilst their antibacterial mode of action is still poorly understood, the prime target of FFA action is the cell membrane, where FFAs disrupt the electron transport chain and oxidative phosphorylation. Besides interfering with cellular energy production, FFA action may also result from the inhibition of enzyme activity, impairment of nutrient uptake, generation of peroxidation and auto-oxidation degradation products or direct lysis of bacterial cells. Their broad spectrum of activity, non-specific mode of action and safety makes them attractive as antibacterial agents for various applications in medicine, agriculture and food preservation, especially where the use of conventional antibiotics is undesirable or prohibited. Moreover, the evolution of inducible FFA-resistant phenotypes is less problematic than with conventional antibiotics. The potential for commercial or biomedical exploitation of antibacterial FFAs, especially for those from natural sources, is discussed.

/pdf/antibacterial-free-fatty-acids-activities-mechanisms-of-5ew888s9bz.pdf

Antibacterial free fatty acids: activities, mechanisms of action and biotechnological potential

To determine in more detail the reaction of Folin-Ciocalteu phenol reagent with nitrogen compounds, a number of hydroxylamine-related compounds and a large number of guanidine-containing compounds were tested In general, guanidine compounds did not react strongly unless they were hydroxyamino or hydrazino derivatives The non-hydroxyamino paralytic shellfish poison saxitoxin, however, reacted to a significant extent This may be due to the presence of a five-membered ring structure and its analogy to 2-aminopurines, which react strongly A number of simpler amines were also tested Tertiary aliphatic amines, but not primary, secondary, or quaternary amines, reacted strongly with the reagent Primary, secondary, and tertiary aromatic amines all reacted strongly with the reagent Reactivity was extended to pyrroles and indole derivatives but not to imidazole and benzimidazole derivatives Defining the reactivity of Folin-Ciocalteau phenol reagent with nitrogen compounds extends the usefulness of the reagent for the detection and determination of certain nitrogen compounds in basic extracts by colorimetric means and by thin-layer chromatography

Utilization of Folin-Ciocalteu phenol reagent for the detection of certain nitrogen compounds.

Experiments were run to determine the effect of filtrate from incubated Aphanizomenonflos-aquae on the thoracic appendage beat rate and frequency of postabdominal rejections by Daphnia carinata. Comparisons were made between the response to Aphanizomenon filtrate and to purified saxitoxin (STX). The short-term response pattern to the filtrate included an immediate 30-50% depression of thoracic appendage beat rate and elevation of postabdominal rejection rate followed by slowly decreasing thoracic appendage beat rate and increasing postabdominal rejection rate during the 1 O-min exposure. Animals recovered to pretreatment activity rates in <5 min. A similar response was observed in STX, except that Daphnia began to recover immediately from the thoracic appendage beat rate inhibition. Animals recovered to -60% of pretreatment activity after l-2 h in Aphanizomenon filtrate, whereas in STX they returned to pretreatment activity levels after - 1 h of exposure to the neurotoxin. Water from a lake with a winter bloom of A. Jlos-aquae produced the same pattern of thoracic appendage beat rate and postabdominal rejection rate response as seen with the cultured Aphanizomenon. A comparison of responses to STX and the Aphanizomenon filtrate indicates the effect on D. carinata is through chemosensory stimulation rather than neuromotor inhibition.

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1995.40.2.0263

Effects of products released by Aphanizomenon flos-aquae and purified saxitoxin on the movements of Daphnia carinata feeding appendages

Volatile organic compounds produced by cyanobacteria and algae in freshwater lakes and contributing to the odour of lakes were tested for their ability to inhibit the growth of the green alga Chlorella pyrenoidosa by the paper disk-agar plate method Geosmin, β-cyclocitral, α- and β-ionones, and geranylacetone exhibited inhibitory activity by diffusion in the 2-5 mg ml−1 range α- and β-Ionones and geranylacetone showed inhibition through the vapor phase at 10 mg ml−1 Dimethyl disulfide showed no inhibition at 10 mg ml−1 The norcarotenoids, which are prominent contributors to the odour of lake waters, were not significantly active in inhibiting the growth of Chlorella, with activity in the same range as monoterpene alcohols in general

Activity of cyanobacterial and algal odor compounds found in lake waters on green alga Chlorella pyrenoidosa growth

Comparison of the toxins of the blue-green alga Aphanizomenon flos-aquae with the Gonyaulax toxins

Isolation of Gonyaulax tamarensis toxins from soft shell clams (Mya arenaria) and a thin-layer chromatographic-fluorometric method for their detection.

Miyoshi Ikawa

Papers

Utilization of Folin-Ciocalteu phenol reagent for the detection of certain nitrogen compounds.

Effects of products released by Aphanizomenon flos-aquae and purified saxitoxin on the movements of Daphnia carinata feeding appendages

Activity of cyanobacterial and algal odor compounds found in lake waters on green alga Chlorella pyrenoidosa growth

Comparison of the toxins of the blue-green alga Aphanizomenon flos-aquae with the Gonyaulax toxins

Isolation of Gonyaulax tamarensis toxins from soft shell clams (Mya arenaria) and a thin-layer chromatographic-fluorometric method for their detection.