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Anatoxin-a and Homoanatoxin

Anatoxin-a and homoanatoxin-a are potent agonists of the nicotinic acetylcholine receptor, and they provoke the rapid death of animals by acute asphyxia when ingested [73]. Cases of animal death due to cyanobacterial toxin exposure are regularly reported in different places around the world [74-76]. Hence, it is recognized that the release of cyanobacterial toxins in waters and water supplies has major implications for public health and for the environment. Therefore, several countries [Pg.402]

HVE-MEMBERED HETEROCYCLIC RINGS AND THEIR FUSED DERIVATIVES [Pg.404]

The first studies on the biosynthesis of these neurotoxin involved feeding experiments using labeled precursors, which, although allowed the researchers to establish that anatoxin-a results from the condensation of three acetate units on (5)-l-pyrroline-5-carboxylate (P5C) that is derived from glutamate followed by a decarboxylation and that homoanatoxin-a would result from methylation of anatoxin-a, could not lead to the elucidation of the individual chemical steps of the biosynthetic pathway [77]. [Pg.404]


Araoz, R., Nghiem, H.O., Rippka, R., Ealihroda, N., de Marsac, N.T., and Herdman, M. 2005. Neurotoxins in axenic oscilla-torian cyanobacteria coexistence of anatoxin-a and homoanatoxin-a determined by ligand-binding assay and GC/MS. Microbiol 151, 1263-1273. [Pg.153]

Zotou, A., Jefferies, T.M., Brough, P.A., and Gallagher, T. 1993. Determination of anatoxin-a and homoanatoxin in blue-green algal extracts by high-performance liquid chromatography and gas chromatography-mass spectrometry. Analyst 118, 753-758. [Pg.158]

The neurotoxins known to be produced by freshwater cyanobacteria include anatoxin-a and homoanatoxin-a, ana-toxin-a(s), and saxitoxins. Their target is the neuromuscular system, and they can paralyze peripheral, skeletal muscle, including respiratory muscles. Death ensues as a result of respiratory arrest within a few minutes to a few hours (see reviews by Duy et al, 2000 Kuiper-Goodman et al, 1999). [Pg.374]

Figure 5.19 Proposed biosynthetic pathway to anatoxin-a and homoanatoxin-a starting from proline. KS, ketosynthase AT, acyltransferase KR, ketoreductase DH, dehydrogenase ER, enoylreductase ACP, acyl carrier protein Cy, cyclase and CM, methyllransferase. Figure 5.19 Proposed biosynthetic pathway to anatoxin-a and homoanatoxin-a starting from proline. KS, ketosynthase AT, acyltransferase KR, ketoreductase DH, dehydrogenase ER, enoylreductase ACP, acyl carrier protein Cy, cyclase and CM, methyllransferase.
In freshwater, harmful algal blooms are mostly attributed to cyanobacteria, also known as blue-green algae. Cyanobacterial neurotoxins fall into three different categories anatoxin-a and homoanatoxin-a, anatoxin-a(S), and saxitoxins (see Figure 1 and Figure 5 for chemical structures). As mentioned above, saxitoxins are produced by marine dinoflagel-lates and are known to concentrate in seafood and cause PSP in humans. Saxitoxins can be also found in cyanobacteria, where the presence of at least 19 different saxitoxins has been reported. [Pg.4874]

Cyanobacterial neurotoxins primarily target cholinergic synapses or voltagegated ion channels. For example, anatoxin-a and homoanatoxin-a are nicotinic acetylcholine receptor agonists [1-3], while anatoxin-a(s) irreversibly inhibits acetylcholinesterase activity [4, 5]. The saxitoxins, on the other hand, exert their toxicity via the inhibition of voltage-gated sodium, calcium, and potassium channels [6-8]. Despite their different modes of action, when ingested in acute doses, the alkaloid neurotoxins impart similar symptoms of paralysis and respiratory failure. [Pg.44]

The cyanotoxins display remarkable structural diversity, however, most can be classified as cyclic peptides, depsipeptides, lipopeptides, or alkaloids [15-17]. Among the alkaloid neurotoxins, which are the focus of this chapter, anatoxin-a and homoanatoxin-a can be described as low molecular weight secondary bicyclic... [Pg.44]

Because the presence of anatoxin-a and homoanatoxin-a in the environment represents a risk for animals and humans, several analytical methods have been designed to detect these toxins as well as their natural derivatives (Fig. 3.2). GC-MS was first used to detect and quantify anatoxin-a or its A -acetyl derivative [51,52,66]. High Pressure Liquid chromatography (HPLQ coupled to UV detection was also used, although this detectirm method is not veiy sensitive [67]. Thus, to improve the sensitivity, several authors have used pre-derivatization with a fluorophore, which reacts on the amine of anatoxin-a or of homoanatoxin-a, followed by separation by HPLC coupled to a fluorescence detector [56, 68, 69]. However, the derivatization might lead to false positives even if the technique was improved to remove primary amines present in the sample [70] or by crmcentratirm by extraction of anatoxin-a prior to analysis [71,72]. It is now accepted that the best analytical technique relies on the use of HPLC coupled to tandem mass spectrometry (LC-MS, or even LC-MS") without derivatization to avoid... [Pg.47]

Fig. 3.2 Chemical structure of the natural derivatives of anatoxin-a and homoanatoxin-a, so far identified... Fig. 3.2 Chemical structure of the natural derivatives of anatoxin-a and homoanatoxin-a, so far identified...
Fig. 3.3 Biosynthesis of anatoxin-a and homoanatoxin-a in cyanobacteria genes and biosynthetic pathway... Fig. 3.3 Biosynthesis of anatoxin-a and homoanatoxin-a in cyanobacteria genes and biosynthetic pathway...
Mejean A, Mann S, Maldiney T, Vassiliadis G, Lequin O, Ploux O (2009) Evidence that biosynthesis of the neurotoxic alkaloids anatoxin-a and homoanatoxin-a in the cyanobacterium Oscillatoria PCC 6506 occurs on a modular polyketide synthase initiated by L-proline. J Am Chem Soc 131 7512-7513. doi 10.1021/ja9024353... [Pg.72]

Wood SA, Holland FT, MacKcmzie L (2011) Development of solid phase adsmption toxin tracking (SPATT) for monitoring anatoxin-a and homoanatoxin-a in river wato. Otemosphere 82 888-894. doi 10.1016/j.chemosphere.2010.10.055... [Pg.75]

Wood SA, Heath MW, Kuhajek J, Ryan KG (2010) Fine-scale spatial variability in anatoxin-a and homoanatoxin-a concentrations in benthic cyanobacterial mats implication for monitoring and management. J Appl Microbiol 109 2011-2018. doi 10.1111/j.l365-2672.2010.04831.x... [Pg.75]

Heath MW, Wood SA, Ryan KG (2011) Spatial and temporal variability in Phormidium mats and associated anatoxin-a and homoanatoxin-a in two New Zealand rivers. Aquat Microb Ecol 64 69-79. doi 10.3354/ame01516... [Pg.75]

Anatoxin-a and homoanatoxin-a are usually found in freshwater and salt marshes Oscillatorian cyanobacteria. The main genera that contain these neurotoxins are Ana-baena, Aphanizomenon, Cylindrospermum, and Oscillatoria (Araoz et al., 2005). However, homoanatoxin-a was reported recently in the New Caledonian cyanobacterium Hydrocoleum lyngbyaceum (Mejean et al., 2010). [Pg.177]


See other pages where Anatoxin-a and Homoanatoxin is mentioned: [Pg.142]    [Pg.145]    [Pg.163]    [Pg.146]    [Pg.666]    [Pg.821]    [Pg.402]    [Pg.402]    [Pg.404]    [Pg.404]    [Pg.405]    [Pg.406]    [Pg.4875]    [Pg.42]    [Pg.43]    [Pg.45]    [Pg.45]    [Pg.47]    [Pg.50]    [Pg.50]    [Pg.52]    [Pg.53]    [Pg.54]    [Pg.77]   


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