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1.
PLoS Negl Trop Dis ; 14(3): e0008060, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32163415

RESUMO

The northeast (NE) region of Brazil commonly goes through drought periods, which favor cyanobacterial blooms, capable of producing neurotoxins with implications for human and animal health. The most severe dry spell in the history of Brazil occurred between 2012 and 2016. Coincidently, the highest incidence of microcephaly associated with the Zika virus (ZIKV) outbreak took place in the NE region of Brazil during the same years. In this work, we tested the hypothesis that saxitoxin (STX), a neurotoxin produced in South America by the freshwater cyanobacteria Raphidiopsis raciborskii, could have contributed to the most severe Congenital Zika Syndrome (CZS) profile described worldwide. Quality surveillance showed higher cyanobacteria amounts and STX occurrence in human drinking water supplies of NE compared to other regions of Brazil. Experimentally, we described that STX doubled the quantity of ZIKV-induced neural cell death in progenitor areas of human brain organoids, while the chronic ingestion of water contaminated with STX before and during gestation caused brain abnormalities in offspring of ZIKV-infected immunocompetent C57BL/6J mice. Our data indicate that saxitoxin-producing cyanobacteria is overspread in water reservoirs of the NE and might have acted as a co-insult to ZIKV infection in Brazil. These results raise a public health concern regarding the consequences of arbovirus outbreaks happening in areas with droughts and/or frequent freshwater cyanobacterial blooms.


Assuntos
Morte Celular/efeitos dos fármacos , Microcefalia/patologia , Envenenamento/complicações , Envenenamento/patologia , Saxitoxina/toxicidade , Infecção por Zika virus/complicações , Infecção por Zika virus/patologia , Animais , Toxinas Bacterianas/análise , Toxinas Bacterianas/toxicidade , Encéfalo/patologia , Brasil/epidemiologia , Células Cultivadas , Modelos Animais de Doenças , Surtos de Doenças , Feminino , Humanos , Incidência , Toxinas Marinhas/análise , Toxinas Marinhas/toxicidade , Camundongos Endogâmicos C57BL , Microcistinas/análise , Microcistinas/toxicidade , Modelos Teóricos , Neurotoxinas/análise , Neurotoxinas/toxicidade , Saxitoxina/análise , Água/química
2.
PLoS One ; 14(12): e0227122, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31887191

RESUMO

Malayan krait (Bungarus candidus) is a medically important snake species found in Southeast Asia. The neurotoxic effects of envenoming present as flaccid paralysis of skeletal muscles. It is unclear whether geographical variation in venom composition plays a significant role in the degree of clinical neurotoxicity. In this study, the effects of geographical variation on neurotoxicity and venom composition of B. candidus venoms from Indonesia, Malaysia and Thailand were examined. In the chick biventer cervicis nerve-muscle preparation, all venoms abolished indirect twitches and attenuated contractile responses to nicotinic receptor agonists, with venom from Indonesia displaying the most rapid neurotoxicity. A proteomic analysis indicated that three finger toxins (3FTx), phospholipase A2 (PLA2) and Kunitz-type serine protease inhibitors were common toxin groups in the venoms. In addition, venom from Thailand contained L-amino acid oxidase (LAAO), cysteine rich secretory protein (CRISP), thrombin-like enzyme (TLE) and snake venom metalloproteinase (SVMP). Short-chain post-synaptic neurotoxins were not detected in any of the venoms. The largest quantity of long-chain post-synaptic neurotoxins and non-conventional toxins was found in the venom from Thailand. Analysis of PLA2 activity did not show any correlation between the amount of PLA2 and the degree of neurotoxicity of the venoms. Our study shows that variation in venom composition is not limited to the degree of neurotoxicity. This investigation provides additional insights into the geographical differences in venom composition and provides information that could be used to improve the management of Malayan krait envenoming in Southeast Asia.


Assuntos
Bungarotoxinas/toxicidade , Bungarus , Junção Neuromuscular/efeitos dos fármacos , Neurotoxinas/toxicidade , Proteínas de Répteis/toxicidade , Animais , Bungarotoxinas/análise , Galinhas , Modelos Animais de Doenças , Humanos , Indonésia , Malásia , Masculino , Síndromes Neurotóxicas/diagnóstico , Síndromes Neurotóxicas/etiologia , Neurotoxinas/análise , Proteoma/análise , Proteoma/toxicidade , Proteômica/métodos , Proteínas de Répteis/análise , Índice de Gravidade de Doença , Mordeduras de Serpentes/complicações , Tailândia
3.
BMC Plant Biol ; 19(1): 489, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31718544

RESUMO

BACKGROUND: Grass pea (Lathyrus sativus) is an underutilised crop with high tolerance to drought and flooding stress and potential for maintaining food and nutritional security in the face of climate change. The presence of the neurotoxin ß-L-oxalyl-2,3-diaminopropionic acid (ß-L-ODAP) in tissues of the plant has limited its adoption as a staple crop. To assist in the detection of material with very low neurotoxin toxin levels, we have developed two novel methods to assay ODAP. The first, a version of a widely used spectrophotometric assay, modified for increased throughput, permits rapid screening of large populations of germplasm for low toxin lines and the second is a novel, mass spectrometric procedure to detect very small quantities of ODAP for research purposes and characterisation of new varieties. RESULTS: A plate assay, based on an established spectrophotometric method enabling high-throughput ODAP measurements, is described. In addition, we describe a novel liquid chromatography mass spectrometry (LCMS)-based method for ß-L-ODAP-quantification. This method utilises an internal standard (di-13C-labelled ß-L-ODAP) allowing accurate quantification of ß-L-ODAP in grass pea tissue samples. The synthesis of this standard is also described. The two methods are compared; the spectrophotometric assay lacked sensitivity and detected ODAP-like absorbance in chickpea and pea whereas the LCMS method did not detect any ß-L-ODAP in these species. The LCMS method was also used to quantify ß-L-ODAP accurately in different tissues of grass pea. CONCLUSIONS: The plate-based spectrophotometric assay allows quantification of total ODAP in large numbers of samples, but its low sensitivity and inability to differentiate α- and ß-L-ODAP limit its usefulness for accurate quantification in low-ODAP samples. Coupled to the use of a stable isotope internal standard with LCMS that allows accurate quantification of ß-L-ODAP in grass pea samples with high sensitivity, these methods permit the identification and characterisation of grass pea lines with a very low ODAP content. The LCMS method is offered as a new 'gold standard' for ß-L-ODAP quantification, especially for the validation of existing and novel low- and/or zero-ß-L-ODAP genotypes.


Assuntos
Diamino Aminoácidos/análise , Lathyrus/química , Neurotoxinas/análise , Cromatografia Líquida/economia , Cromatografia Líquida/métodos , Custos e Análise de Custo , Marcação por Isótopo , Lathyrus/genética , Espectrometria de Massas/economia , Espectrometria de Massas/métodos , Padrões de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrofotometria/economia , Espectrofotometria/métodos , Fatores de Tempo
4.
Chemosphere ; 236: 124404, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545201

RESUMO

Tetrodotoxin (TTX) is a potent neurotoxin responsible for countless human intoxications and deaths around the world. The distribution of TTX and its analogues is diverse and the toxin has been detected in organisms from both marine and terrestrial environments. Increasing detections seafood species, such as bivalves and gastropods, has drawn attention to the toxin, reinvigorating scientific interest and regulatory concerns. There have been reports of TTX in 21 species of bivalves and edible gastropods from ten countries since the 1980's. While TTX is structurally dissimilar to saxitoxin (STX), another neurotoxin detected in seafood, it has similar sodium channel blocking action and potency and both neurotoxins have been shown to have additive toxicities. The global regulatory level for the STX group toxins applied to shellfish is 800 µg/kg. The presence of TTX in shellfish is only regulated in one country; The Netherlands, with a regulatory level of 44 µg/kg. Due to the recent interest surrounding TTX in bivalves, the European Food Safety Authority established a panel to assess the risk and regulation of TTX in bivalves, and their final opinion was that a concentration below 44 µg of TTX per kg of shellfish would not result in adverse human effects. In this article, we review current knowledge on worldwide TTX levels in edible gastropods and bivalves over the last four decades, the different methods of detection used, and the current regulatory status. We suggest research needs that will assist with knowledge gaps and ultimately allow development of robust monitoring and management protocols.


Assuntos
Bivalves/química , Contaminação de Alimentos/análise , Gastrópodes/química , Frutos do Mar/análise , Tetrodotoxina/análise , Animais , Contaminação de Alimentos/legislação & jurisprudência , Inocuidade dos Alimentos , Humanos , Países Baixos , Neurotoxinas/análise , Neurotoxinas/farmacocinética , Saxitoxina/análise , Tetrodotoxina/farmacocinética
5.
Anal Chim Acta ; 1085: 91-97, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31522735

RESUMO

Acetylcholinesterase (AChE), an efficient biocatalyst known to hydrolyze the neurotransmitter acetylcholine, could be inactivated in the presence of insecticides, nerve agents or other drug inhibitors to thus result in disrupted neurotransmission. Improvement in the peripheral cholinergic function, as well as overall cognition and neuronal functions of an exposed system could be achieved if the mechanisms of inhibitions are deactivated in a controlled fashion and with rapid response time. Herein, we proposed to develop a simple AChE biosensor capable to realize the rapid detection of neurotoxins. Our approach uses a nanoporous gold film (NPGF) and reduced graphene oxide-tin dioxide nanoparticle (RGO-SnO2) nanocomposite to define the highly active electrode interface where the electrochemical monitoring of the interaction between AChE and its target molecule, fasciculin, could take place. Our results demonstrate that the established biosensor had the ability to monitor fasciculin concentrations at the ultra-low limit of detection of 8 pM, an inhibition rate of 8% and within only 30min of electrochemical exposure. Our study provides a convenient technology for the rapid and ultrasensitive detection of neurotoxins and has the potential for large applicability to other drugs or toxins screening.


Assuntos
Venenos Elapídicos/análise , Ouro/química , Nanoporos , Neurotoxinas/análise , Técnicas Eletroquímicas , Eletrodos , Propriedades de Superfície
6.
PLoS One ; 14(8): e0220698, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31386693

RESUMO

The neurotoxin ß-N-methylamino-L-alanine (BMAA), suspected to trigger neurodegenerative diseases, can be produced during cyanobacterial bloom events and subsequently affect ecosystems and water sources. Some of its isomers including ß-amino-N-methylalanine (BAMA), N-(2-aminoethyl) glycine (AEG), and 2,4-diaminobutyric acid (DAB) may show different toxicities than BMAA. Here, we set out to provide a fast and sensitive method for the monitoring of AEG, BAMA, DAB and BMAA in surface waters. A procedure based on aqueous derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) was investigated for this purpose. Under optimized conditions, a small aqueous sample aliquot (5 mL) was spiked with BMAA-d3 internal standard, subjected to FMOC-Cl derivatization, centrifuged, and analyzed. The high-throughput instrumental method (10 min per sample) involved on-line pre-concentration and desalting coupled to ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). Chromatographic gradient and mobile phases were adjusted to obtain suitable separation of the 4 isomers. The method limits of detection were in the range of 2-5 ng L-1. In-matrix validation parameters including linearity range, accuracy, precision, and matrix effects were assessed. The method was applied to surface water samples (n = 82) collected at a large spatial scale in lakes and rivers in Canada. DAB was found in >70% of samples at variable concentrations (<3-1,900 ng L-1), the highest concentrations corresponding to lake samples in cyanobacterial bloom periods. BMAA was only reported (110 ng L-1) at one HAB-impacted location. This is one of the first studies to report on the profiles of AEG, BAMA, DAB, and BMAA in background and impacted surface waters.


Assuntos
Diamino Aminoácidos/análise , Agonistas de Aminoácidos Excitatórios/análise , Neurotoxinas/análise , Canadá , Cromatografia Líquida/métodos , Cianobactérias/química , Fluorenos/química , Isomerismo , Lagos/química , Limite de Detecção , Espectrometria de Massas/métodos , Rios/química
7.
Toxins (Basel) ; 11(6)2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31212624

RESUMO

Tetrodotoxin (TTX) is a potent neurotoxin that is receiving increasing interest in the European Union because it has been found in different fishery products (fish, bivalves and gastropods) captured in European waters. Since available information is scarce, further analytical data regarding the incidence of this toxin in European fishery products is needed in order to perform an appropriate risk assessment devoted to protecting consumers' health. Hence, samples of bivalves and gastropods were collected at different points of the Spanish coast and analyzed by high-performance hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) to evaluate the presence of TTX. None of the analyzed samples showed TTX above an internal threshold of 10 µg/kg or even showed a peak under it. Our results on TTX occurrence obtained in bivalve molluscs and gastropods did not show, at least in the studied areas, a risk for public health. However, taking into account previous positive results obtained by other research groups, and since we did not detect TTX in our samples, a more completed study increasing sampling frequency is needed to ensure proper risk evaluation towards the food safety of these products.


Assuntos
Bivalves/química , Contaminação de Alimentos/análise , Gastrópodes/química , Neurotoxinas/análise , Tetrodotoxina/análise , Animais , Monitoramento Biológico , Inocuidade dos Alimentos , Espanha
8.
Arch Razi Inst ; 74(2): 135-142, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31232563

RESUMO

Scorpion venom is the richest source of peptide toxins with high levels of specific interactions with different ion-channel membrane proteins. The present study involved the amplification and sequencing of a 310-bp cDNA fragment encoding a beta-like neurotoxin active on sodium ion-channel from the venom glands of scorpion Androctonus crassicauda belonging to the Buthidae family using reverse transcription polymerase chain reaction (RT-PCR) technique. The amplified complementary DNA (cDNA) fragment had a coding sequence of 240 bp. The deduced precursor open-reading frame was composed of 80 amino acid residues contain a signal peptide of 22 amino acid residues, followed by a mature toxin of 58 amino acids. It had a molecular mass of 6.84 kDa and isoelectric point of 4.58. The sequence similarity search revealed several matches with the scorpion toxin-like domain of toxin-3 superfamily with a homology range of 35- 75%. Multiple alignments and secondary structure prediction demonstrated that the toxin peptide deduced from the amplified cDNA was related to the long-chain neurotoxins in size but stabilized by three disulfide bridges instead of four. The level of difference implies that the corresponding genes have originated from a common ancestor. This level of difference may also confirm an evolutionary link between the &lsquo;short-chain&rsquo; and &lsquo;long-chain&rsquo; toxins. The analysis showed one major segment within this neurotoxin with maximal hydrophilicity which was predicted to be antigenic by inducing an antibody response.


Assuntos
Neurotoxinas/análise , Venenos de Escorpião/análise , Escorpiões/química , Sequência de Aminoácidos , Animais , DNA Complementar/análise , Dissulfetos/análise , Neurotoxinas/química , Venenos de Escorpião/química , Alinhamento de Sequência
9.
Toxins (Basel) ; 11(5)2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-31096619

RESUMO

Seafood is an emerging health food, and interest in improving the quality of seafood is increasing. Saxitoxin (STX) is a neurotoxin produced by marine dinoflagellates that is accumulated in seafood. It can block the neuronal transmission between nerves and muscle cell membranes, resulting in the disturbance of neuromuscular transmission and subsequent voluntary muscle paralysis. Here, we developed a new aptamer for the detection of STX using graphene oxide-systematic evolution of ligands by exponential enrichment (GO-SELEX). Furthermore, we confirmed sensitivity and selectivity of the developed aptamer specific to STX using a localized surface plasmon resonance (LSPR) sensor. The sensing chip was fabricated by fixing the new STX aptamer immobilized on the gold nanorod (GNR) substrate. The STX LSPR aptasensor showed a broad, linear detection range from 5 to 10,000 µg/L, with a limit of detection (LOD) of 2.46 µg/L (3σ). Moreover, it was suitable for the detection of STX (10, 100, and 2000 µg/L) in spiked mussel samples and showed a good recovery rate (96.13-116.05%). The results demonstrated that the new STX aptamer-modified GNR chip was sufficiently sensitive and selective to detect STX and can be applied to real samples as well. This LSPR aptasensor is a simple, label-free, cost-effective sensing system with a wide detectable range.


Assuntos
Bivalves/química , Neurotoxinas/análise , Saxitoxina/análise , Animais , Aptâmeros de Nucleotídeos/química , Contaminação de Alimentos/análise , Ouro/química , Grafite/química , Nanotubos/química , Alimentos Marinhos/análise , Ressonância de Plasmônio de Superfície
10.
Chemosphere ; 229: 332-340, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31078890

RESUMO

In freshwater aquaculture ecosystems with high-frequency occurrences of cyanobacteria blooms, a chronic neurotoxic cyanobacteria toxin, ß-N-methylamino-l-alanine (BMAA), is a new pollutant that affects the normal growth, development, and reproduction of aquaculture organisms. BMAA poses a great threat to the food quality and food safety of aquatic products. In this paper, high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) was used to detect the contents of BMAA in the edible portions of six representative freshwater aquaculture products (Corbicula fluminea, Anodonta arcaeformis, Macrobrachium nipponense, Eriocheir sinensis, Ctenopharyngodon idella, and Mylopharyngodon piceus) from Taihu Lake Basin in China. Noncarcinogenic health risks were assessed with reference to the model recommended by the International Environmental Modelling and Software Society and based on the biomagnification characteristics of BMAA in the various aquaculture products investigated by the stable nitrogen isotope technique. The average BMAA concentrations in the edible portions of the six freshwater culture products were from 2.05 ±â€¯1.40 to 4.21 ±â€¯1.26 µg g-1 dry weight (DW), and the difference was significant (p < 0.05), such a difference increased with the increase in the trophic level in the aquaculture products. Although a biomagnification indication was observed, the trophic magnification factor (TMF) was only 1.20 which exhibited a relatively low biomagnification efficiency. The annual health risk values of BMAA in all the measured aquatic products were within the maximum tolerable range (<1 × 10-6 a-1), and the health risk increased with the increase in the trophic level. The risk values of BMAA in the six freshwater aquaculture products for children was slightly higher than the negligible level (<1 × 10-7 a-1), thus there might have potential health risks for children's long-term consumption. Considering China's national conditions, the guidance values of BMAA based on the quality and safety of freshwater aquaculture products were proposed to be 7.2 µg g-1 DW for adults and 1.8 µg g-1 DW for children.


Assuntos
Diamino Aminoácidos/análise , Aquicultura/métodos , Toxinas Bacterianas/análise , Lagos/química , Toxinas Marinhas/análise , Microcistinas/análise , Medição de Risco , Adulto , Diamino Aminoácidos/normas , Aquicultura/normas , Criança , China , Cromatografia Líquida de Alta Pressão , Inocuidade dos Alimentos , Humanos , Neurotoxinas/análise , Espectrometria de Massas em Tandem
11.
PLoS One ; 14(3): e0213346, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30893348

RESUMO

Dolphin stranding events occur frequently in Florida and Massachusetts. Dolphins are an excellent sentinel species for toxin exposures in the marine environment. In this report we examine whether cyanobacterial neurotoxin, ß-methylamino-L-alanine (BMAA), is present in stranded dolphins. BMAA has been shown to bioaccumulate in the marine food web, including in the muscles and fins of sharks. Dietary exposure to BMAA is associated with the occurrence of neurofibrillary tangles and ß-amyloid plaques in nonhuman primates. The findings of protein-bound BMAA in brain tissues from patients with Alzheimer's disease has advanced the hypothesis that BMAA may be linked to dementia. Since dolphins are apex predators and consume prey containing high amounts of BMAA, we examined necropsy specimens to determine if dietary and environmental exposures may result in the accumulation of BMAA in the brains of dolphins. To test this hypothesis, we measured BMAA in a series of brains collected from dolphins stranded in Florida and Massachusetts using two orthogonal analytical methods: 1) high performance liquid chromatography, and 2) ultra-performance liquid chromatography with tandem mass spectrometry. We detected high levels of BMAA (20-748 µg/g) in the brains of 13 of 14 dolphins. To correlate neuropathological changes with toxin exposure, gross and microscopic examinations were performed on cortical brain regions responsible for acoustico-motor navigation. We observed increased numbers of ß-amyloid+ plaques and dystrophic neurites in the auditory cortex compared to the visual cortex and brainstem. The presence of BMAA and neuropathological changes in the stranded dolphin brain may help to further our understanding of cyanotoxin exposure and its potential impact on human health.


Assuntos
Diamino Aminoácidos/toxicidade , Encéfalo/metabolismo , Encéfalo/patologia , Cianobactérias/patogenicidade , Golfinhos/metabolismo , Neurotoxinas/toxicidade , Diamino Aminoácidos/análise , Animais , Golfinho Nariz-de-Garrafa/metabolismo , Encéfalo/efeitos dos fármacos , Golfinhos Comuns/metabolismo , Monitoramento Ambiental , Cadeia Alimentar , Proliferação Nociva de Algas , Humanos , Massachusetts , Neurotoxinas/análise , Placa Amiloide/patologia , Espécies Sentinelas
12.
Toxins (Basel) ; 11(3)2019 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-30893800

RESUMO

Most knowledge of spider venom concerns neurotoxins acting on ion channels, whereas proteins and their significance for the envenomation process are neglected. The here presented comprehensive analysis of the venom gland transcriptome and proteome of Cupiennius salei focusses on proteins and cysteine-containing peptides and offers new insight into the structure and function of spider venom, here described as the dual prey-inactivation strategy. After venom injection, many enzymes and proteins, dominated by α-amylase, angiotensin-converting enzyme, and cysteine-rich secretory proteins, interact with main metabolic pathways, leading to a major disturbance of the cellular homeostasis. Hyaluronidase and cytolytic peptides destroy tissue and membranes, thus supporting the spread of other venom compounds. We detected 81 transcripts of neurotoxins from 13 peptide families, whereof two families comprise 93.7% of all cysteine-containing peptides. This raises the question of the importance of the other low-expressed peptide families. The identification of a venom gland-specific defensin-like peptide and an aga-toxin-like peptide in the hemocytes offers an important clue on the recruitment and neofunctionalization of body proteins and peptides as the origin of toxins.


Assuntos
Proteoma , Venenos de Aranha/química , Transcriptoma , Animais , Proteínas de Artrópodes/análise , Neurotoxinas/análise , Peptídeos/análise , Comportamento Predatório , Aranhas
13.
Ecotoxicol Environ Saf ; 172: 72-81, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30682636

RESUMO

Environmental exposure to the amino acid ß-methylamino-L-alanine (BMAA) was linked to the high incidence of neurodegenerative disease first reported on the island of Guam in the 1940s and has more recently been implicated in an increased incidence of amyotrophic lateral sclerosis (ALS) in parts of the USA. BMAA has been shown to be produced by a range of cyanobacteria and some marine diatoms and dinoflagellates in different parts of the world. BMAA is commonly found with two of its constitutional isomers: 2,4- diaminobutyric acid (2,4-DAB) and N-(2-aminoethyl) glycine (AEG). These isomers are thought to be co-produced by the same organisms that produce BMAA and MS/MS analysis following LC separation can add an additional level of specificity over LC-FL. Although the presence of BMAA and 2,4-DAB in surface scum samples from several sites in Australia has been reported, which Australian cyanobacterial species are capable of BMAA, 2,4-DAB and AEG production remains unknown. The aims of the present studies were to identify some of the cyanobacterial genera or species that can produce BMAA, 2,4-DAB and AEG in freshwater cyanobacteria blooms in eastern Australia. Eleven freshwater sites were sampled and from these, 19 single-species cyanobacterial cultures were established. Amino acids were extracted from cyanobacterial cultures and analysed using liquid chromatography-tandem mass spectrometry. BMAA was detected in 17 of the 19 isolates, 2,4-DAB was detected in all isolates, and AEG was detected in 18 of the 19 isolates, showing the prevalence of these amino acids in Australian freshwater cyanobacteria. Concentrations of all three isomers in Australian cyanobacteria were generally higher than the concentrations reported elsewhere. This study confirmed the presence of BMAA and its isomers in cyanobacteria isolated from eastern Australian freshwater systems, and determined which Australian cyanobacterial genera or species were capable of producing them when cultured under laboratory conditions.


Assuntos
Diamino Aminoácidos/análise , Diamino Aminoácidos/química , Cianobactérias/química , Aminoácidos/análise , Austrália , Cromatografia Líquida , Água Doce/microbiologia , Glicina/análise , Glicina/química , Isomerismo , Neurotoxinas/análise , Neurotoxinas/química , Espectrometria de Massas em Tandem
14.
Chemosphere ; 219: 997-1001, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30682765

RESUMO

Most cyanobacteria can synthesize the notorious neurotoxin ß-methylamino-l-alanine (BMAA) that is transferred and bioaccumulated through natural food webs of aquatic ecosystems and ultimately arises the potential human health risks by the consumption of BMAA-contaminated aquatic products. Fertilization of cyanobacterial composts in farmlands may also lead to BMAA contamination in soil and its possible transfer and bioaccumulation within major crops, thereby threatening human health. In this study, we first detected a high level of BMAA (1.8-16.3 µg g-1) in cyanobacterial composts. In order to assess the health risks from cyanobacterial composts, we planted Chinese cabbage, a favourite vegetable in China, in BMAA-contaminated soil (4.0 µg BMAA/g soil) and detected the levels of free and protein-associated BMAA in soil and crop organs during the whole growth cycle by HPLC-MS/MS, respectively. Our results demonstrated that BMAA indeed transferred from soil to root, stem and leaf of Chinese cabbage during the growth cycle. The BMAA level finally accumulated in the edible portions was much higher than the initial level in soil, including 13.82 µg g-1 in leaf and 4.71 µg g-1 in stem. The discovery of the neurotoxin BMAA in this vegetable, an ending in human consumption, not only provides a BMAA transfer pathway in farmland ecosystems, but also is alarming and requires attention due to the potential risk of cyanobacterial composts to human health.


Assuntos
Diamino Aminoácidos/farmacocinética , Brassica/metabolismo , Neurotoxinas/farmacocinética , Diamino Aminoácidos/análise , China , Compostagem , Cianobactérias/patogenicidade , Humanos , Neurotoxinas/análise , Solo/química , Microbiologia do Solo
15.
Toxins (Basel) ; 11(1)2019 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-30609849

RESUMO

The most potent of the indole diterpenes, lolitrem B, is found in perennial ryegrass (Lolium perenne L.) infected with the endophyte Epichloë festucae var. lolii (also termed LpTG-1). Ingestion causes a neurological syndrome in grazing livestock called ryegrass staggers disease. To enable the rapid development of new forage varieties, the toxicity of lolitrem B and its biosynthetic intermediates needs to be established. However, most of these indole diterpenes are not commercially available; thus, isolation of these compounds is paramount. A concentrated endophyte-infected perennial ryegrass seed extract was subjected to silica flash chromatography followed by preparative HPLC and purification by crystallization resulting in lolitrem B and the intermediate compounds lolitrem E, paspaline and terpendole B. The four-step isolation and purification method resulted in a 25% yield of lolitrem B. After isolation, lolitrem B readily degraded to its biosynthetic intermediate, lolitriol. We also found that lolitrem B can readily degrade depending on the solvent and storage conditions. The facile method which takes into consideration the associated instability of lolitrem B, led to the purification of indole diterpenes in quantities sufficient for use as analytical standards for identification in pastures, and/or for toxicity testing in pasture development programs.


Assuntos
Diterpenos/análise , Indóis/análise , Lolium/química , Neurotoxinas/análise , Diterpenos/metabolismo , Endófitos/metabolismo , Epichloe/metabolismo , Contaminação de Alimentos/análise , Indóis/metabolismo , Lolium/microbiologia , Neurotoxinas/metabolismo
16.
Mycotoxin Res ; 35(1): 9-16, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30088215

RESUMO

A tremorgenic syndrome occurs in dogs following ingestion of moldy walnuts, and Penicillium crustosum has been implicated as the offending fungus. This is the first report of suspected moldy walnut toxicosis in man. An adult male ingested approximately eight fungal-infected walnut kernels and after 12 h experienced tremors, generalized pain, incoordination, confusion, anxiety, and diaphoresis. Following symptomatic and supportive treatment at a local hospital, the man made an uneventful recovery. A batch of walnuts (approximately 20) was submitted for mycological culturing and identification as well as for mycotoxin analysis. Penicillium crustosum Thom was the most abundant fungus present on walnut samples, often occurring as monocultures on isolation plates. Identifications were confirmed with DNA sequences. The kernels and shells of the moldy walnuts as well as P. crustosum isolates plated on yeast extract sucrose (YES) and Czapek yeast autolysate (CYA) agars and incubated in the dark at 25 °C for 7 days were screened for tremorgenic mycotoxins and known P. crustosum metabolites using a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method. A relatively low penitrem A concentration of only 1.9 ng/g was detected on the walnut kernels when compared to roquefortine C concentrations of 21.7 µg/g. A similar result was obtained from P. crustosum isolates cultured on YES and CYA, with penitrem A concentrations much lower (0.6-6.4 µg per g mycelium/agar) compared to roquefortine C concentrations (172-1225 µg/g). The authors surmised that besides penitrem A, roquefortine C might also play an additive or synergistic role in intoxication of man.


Assuntos
Contaminação de Alimentos , Juglans/microbiologia , Micotoxicose/diagnóstico , Nozes/microbiologia , Penicillium/isolamento & purificação , Cromatografia Líquida , Microbiologia de Alimentos , Compostos Heterocíclicos de 4 ou mais Anéis/análise , Humanos , Indóis/análise , Masculino , Pessoa de Meia-Idade , Micotoxinas/efeitos adversos , Neurotoxinas/análise , Piperazinas/análise , Espectrometria de Massas em Tandem
17.
Toxins (Basel) ; 10(12)2018 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-30551641

RESUMO

Botulinum neurotoxin type-A (BoNT-A) blocks the release of acetylcholine from peripheral cholinergic nerve terminals and is an important option for the treatment of disorders characterised by excessive cholinergic neuronal activity. Several BoNT-A products are currently marketed, each with unique manufacturing processes, excipients, formulation, and non-interchangeable potency units. Nevertheless, the effects of all the products are mediated by the 150 kDa BoNT-A neurotoxin. We assessed the quantity and light chain (LC) activity of BoNT-A in three commercial BoNT-A products (Dysport®; Botox®; Xeomin®). We quantified 150 kDa BoNT-A by sandwich ELISA and assessed LC activity by EndoPep assay. In both assays, we assessed the results for the commercial products against recombinant 150 kDa BoNT-A. The mean 150 kDa BoNT-A content per vial measured by ELISA was 2.69 ng/500 U vial Dysport®, 0.90 ng/100 U vial Botox®, and 0.40 ng/100 U vial Xeomin®. To present clinically relevant results, we calculated the 150 kDa BoNT-A/US Food and Drug Administration (FDA)-approved dose in adult upper limb spasticity: 5.38 ng Dysport® (1000 U; 2 × 500 U vials), 3.60 ng Botox® (400 U; 4 × 100 U vials), and 1.61 ng Xeomin® (400 U; 4 × 100 U vials). EndoPep assay showed similar LC activity among BoNT-A products. Thus, greater amounts of active neurotoxin are injected with Dysport®, at FDA-approved doses, than with other products. This fact might explain the long duration of action reported across multiple indications, which benefits patients, caregivers, clinicians, and healthcare systems.


Assuntos
Toxinas Botulínicas Tipo A/análise , Fármacos Neuromusculares/análise , Neurotoxinas/análise , Ensaio de Imunoadsorção Enzimática , Humanos , Espasticidade Muscular/tratamento farmacológico , Resultado do Tratamento
18.
Toxins (Basel) ; 10(12)2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30513722

RESUMO

Ontogenetic changes in venom composition have important ecological implications due the relevance of venom in prey acquisition and defense. Additionally, intraspecific venom variation has direct medical consequences for the treatment of snakebite. However, ontogenetic changes are not well documented in most species. The Mexican Black-tailed Rattlesnake (Crotalus molossus nigrescens) is large-bodied and broadly distributed in Mexico. To document venom variation and test for ontogenetic changes in venom composition, we obtained venom samples from twenty-seven C. m. nigrescens with different total body lengths (TBL) from eight states in Mexico. The primary components in the venom were detected by reverse-phase HPLC, western blot, and mass spectrometry. In addition, we evaluated the biochemical (proteolytic, coagulant and fibrinogenolytic activities) and biological (LD50 and hemorrhagic activity) activities of the venoms. Finally, we tested for recognition and neutralization of Mexican antivenoms against venoms of juvenile and adult snakes. We detected clear ontogenetic venom variation in C. m. nigrescens. Venoms from younger snakes contained more crotamine-like myotoxins and snake venom serine proteinases than venoms from older snakes; however, an increase of snake venom metalloproteinases was detected in venoms of larger snakes. Venoms from juvenile snakes were, in general, more toxic and procoagulant than venoms from adults; however, adult venoms were more proteolytic. Most of the venoms analyzed were hemorrhagic. Importantly, Mexican antivenoms had difficulties recognizing low molecular mass proteins (<12 kDa) of venoms from both juvenile and adult snakes. The antivenoms did not neutralize the crotamine effect caused by the venom of juveniles. Thus, we suggest that Mexican antivenoms would have difficulty neutralizing some human envenomations and, therefore, it may be necessary improve the immunization mixture in Mexican antivenoms to account for low molecular mass proteins, like myotoxins.


Assuntos
Venenos de Serpentes/química , Animais , Antivenenos/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Caseínas/química , Crotalus , Feminino , Gelatina/química , Humanos , Dose Letal Mediana , Masculino , México , Camundongos Endogâmicos ICR , Neurotoxinas/análise , Neurotoxinas/farmacologia , Proteínas de Répteis/análise , Proteínas de Répteis/farmacologia , Venenos de Serpentes/farmacologia
19.
Harmful Algae ; 79: 53-57, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30420016

RESUMO

Domoic acid (DA) is a neuroexcitotoxic amino acid that is naturally produced by some species of marine diatoms during harmful algal blooms (HABs). The toxin is transferred through the food web from plantivorous fish and shellfish to marine mammals resulting in significant morbidity and mortality. Due to the timing and location of DA producing HABs, it is well documented that pregnant female California sea lions (CSL) are regularly exposed to DA through their diet thereby posing exposure risks to a neuroteratogen in developing fetuses. In the present study, fluids from 36 fetuses sampled from naturally exposed pregnant CSLs were examined for DA. Domoic acid was detected in 79% of amniotic fluid (n = 24), 67% of allantoic fluid (n = 9), 75% of urine (n = 4), 41% of meconium (n = 17) and 29% of stomach content (n = 21) samples opportunistically collected from CSL fetuses. The distribution of DA in fetal samples indicates an increased prenatal exposure risk due to recirculation of DA in fetal fluids and continuous exposure to the developing brain.


Assuntos
Diatomáceas/metabolismo , Proliferação Nociva de Algas , Ácido Caínico/análogos & derivados , Neurotoxinas/análise , Leões-Marinhos/embriologia , Líquido Amniótico/química , Animais , Diatomáceas/química , Feminino , Feto/química , Cadeia Alimentar , Ácido Caínico/análise , Ácido Caínico/toxicidade , Mamíferos , Neurotoxinas/toxicidade , Gravidez , Risco
20.
Med Hypotheses ; 121: 160-163, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30396472

RESUMO

Municipal fluoridation was a mid-twentieth century innovation based on the medical hypothesis that consuming low doses of fluoride when young provided protection against cavities with only a small risk of mild dental fluorosis, a cosmetic effect. In the 21st century, more than half of American teens are afflicted by dental fluorosis with approximately one in five having moderate to severe dental fluorosis in at least two teeth. Scientific literature since the 1990s has found that even low doses of fluoride adversely affect cognitive-behavioral development and that deficits are correlated with the severity of dental fluorosis in afflicted individuals. Evidence of neurotoxic impact from low dose systemic exposure to fluoride prompted an investigation by a branch of the governmental agency that has promoted fluoridation policy since its 1940's inception. This review identifies ten significant flaws in the design of an animal experiment conducted by the U.S. National Toxicology Program as part of that investigation into the neurotoxic impact of systemic prenatal and postnatal fluoride exposure. The authors hypothesize that organizational bias can and does compromise the integrity of fluoride research.


Assuntos
Fluoretos/análise , Saúde Pública/métodos , Toxicologia/métodos , Toxicologia/normas , Adolescente , Animais , Criança , Cárie Dentária/prevenção & controle , Água Potável , Feminino , Fluoretação , Fluorose Dentária/prevenção & controle , Humanos , Testes de Inteligência , Neurotoxinas/análise , Gravidez , Ratos , Ratos Long-Evans , Projetos de Pesquisa , Risco , Estados Unidos
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