Toxins

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Open AccessArticle

Comparative Study of Various Immune Parameters in Three Bivalve Species during a Natural Bloom of Dinophysis acuminata in Santa Catarina Island, Brazil

by Danielle Ferraz Mello, Luis Antonio de Oliveira Proença and Margherita Anna Barracco

Toxins 2010, 2(5), 1166-1178; https://doi.org/10.3390/toxins2051166 - 25 May 2010

Cited by 52 | Viewed by 10990

Abstract

This study aimed to verify if Dinophysis acuminata natural blooms affected the immune system of three bivalves: the oyster, Crassostrea gigas, the mussel, Perna perna, and the clam, Anomalocardia brasiliana. Animals were obtained from a renowned mariculture farm in the [...] Read more.

This study aimed to verify if Dinophysis acuminata natural blooms affected the immune system of three bivalves: the oyster, Crassostrea gigas, the mussel, Perna perna, and the clam, Anomalocardia brasiliana. Animals were obtained from a renowned mariculture farm in the southern bay of Santa Catarina Island during, and 30 days after (controls), an algal bloom. Various immunological parameters were assessed in the hemolymph of the animals: total and differential hemocyte counts, percentage of apoptotic hemocytes, protein concentration, hemagglutinating titer and phenoloxidase activity. The results showed that the mussel was the most affected species, with several altered immune parameters, whereas the immunological profile of clams and oysters was partially and completely unaffected, respectively. Full article

(This article belongs to the Special Issue Toxins from Aquatic Organisms)

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Open AccessReview

Exfoliative Toxins of Staphylococcus aureus

by Michal Bukowski, Benedykt Wladyka and Grzegorz Dubin

Toxins 2010, 2(5), 1148-1165; https://doi.org/10.3390/toxins2051148 - 25 May 2010

Cited by 167 | Viewed by 39915

Abstract

Staphylococcus aureus is an important pathogen of humans and livestock. It causes a diverse array of diseases, ranging from relatively harmless localized skin infections to life-threatening systemic conditions. Among multiple virulence factors, staphylococci secrete several exotoxins directly associated with particular disease symptoms. These [...] Read more.

Staphylococcus aureus is an important pathogen of humans and livestock. It causes a diverse array of diseases, ranging from relatively harmless localized skin infections to life-threatening systemic conditions. Among multiple virulence factors, staphylococci secrete several exotoxins directly associated with particular disease symptoms. These include toxic shock syndrome toxin 1 (TSST-1), enterotoxins, and exfoliative toxins (ETs). The latter are particularly interesting as the sole agents responsible for staphylococcal scalded skin syndrome (SSSS), a disease predominantly affecting infants and characterized by the loss of superficial skin layers, dehydration, and secondary infections. The molecular basis of the clinical symptoms of SSSS is well understood. ETs are serine proteases with high substrate specificity, which selectively recognize and hydrolyze desmosomal proteins in the skin. The fascinating road leading to the discovery of ETs as the agents responsible for SSSS and the characterization of the molecular mechanism of their action, including recent advances in the field, are reviewed in this article. Full article

(This article belongs to the Special Issue Protein Toxins as Proteases)

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Open AccessReview

Host-Toxin Interactions Involving EspC and Pet, Two Serine Protease Autotransporters of the Enterobacteriaceae

by Fernando Navarro-Garcia, Michael Sonnested and Ken Teter

Toxins 2010, 2(5), 1134-1147; https://doi.org/10.3390/toxins2051134 - 14 May 2010

Cited by 20 | Viewed by 14429

Abstract

EspC and Pet are toxins secreted by the diarrheagenic enteropathogenic and enteroaggregative Escherichia coli pathotypes, respectively. Both toxins have a molecular mass around 110 kDa and belong to the same protein family called Serine Protease Autotransporters of the Enterobacteriaceae (SPATE). Furthermore, both toxins [...] Read more.

EspC and Pet are toxins secreted by the diarrheagenic enteropathogenic and enteroaggregative Escherichia coli pathotypes, respectively. Both toxins have a molecular mass around 110 kDa and belong to the same protein family called Serine Protease Autotransporters of the Enterobacteriaceae (SPATE). Furthermore, both toxins act within the cytosol of intoxicated epithelial cells to disrupt the architecture of the actin cytoskeleton. This cytopathic and enterotoxic effect results from toxin cleavage of the actin-binding protein fodrin, although the two toxins recognize different cleavage sites on fodrin. EspC and Pet also have dramatically different mechanisms of entering the target cell which appear dependent upon the E. coli pathotype. In this review, we compare/contrast EspC and Pet in regards to their mode of delivery into the target cell, their effects on fodrin and the actin cytoskeleton, and their possible effects on the physiology of the intestinal epithelial cell. Full article

(This article belongs to the Special Issue Protein Toxins as Proteases)

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Open AccessReview

Ochratoxin A in Moroccan Foods: Occurrence and Legislation

by Abdellah Zinedine

Toxins 2010, 2(5), 1121-1133; https://doi.org/10.3390/toxins2051121 - 14 May 2010

Cited by 22 | Viewed by 10642

Abstract

Ochratoxin A (OTA) is secondary metabolite naturally produced in food and feed by toxigenic fungi, especially some Aspergillus species and Penicillium verucosum. OTA is one of the most studied mycotoxins and is of great interest due to its toxic effects on human [...] Read more.

Ochratoxin A (OTA) is secondary metabolite naturally produced in food and feed by toxigenic fungi, especially some Aspergillus species and Penicillium verucosum. OTA is one of the most studied mycotoxins and is of great interest due to its toxic effects on human and animals. OTA is produced in different food and feed matrices and contaminates a large range of base foods including cereals and derivatives, spices, dried fruits, wine and coffee, etc. Morocco, a North African country, has a climate characterized by high humidity and temperature, which probably favors the growth of molds. This contribution gives an overview of principal investigations about the presence of OTA in foods available in Morocco. Due to its toxicity, OTA presence is increasingly regulated worldwide, especially in countries of the European Union. However, up until now, no regulation limits were in force in Morocco, probably due to the ignorance of the health and economic problems resulting from OTA contamination. Finally, recommendations and future research directions are given required to assess the situation completely. Full article

(This article belongs to the Special Issue Ochratoxins)

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Open AccessReview

Ochratoxin A Producing Species in the Genus Penicillium

by Francisco Javier Cabañes, Maria Rosa Bragulat and Gemma Castellá

Toxins 2010, 2(5), 1111-1120; https://doi.org/10.3390/toxins2051111 - 14 May 2010

Cited by 92 | Viewed by 14573

Abstract

Ochratoxin A (OTA) producing fungi are members of the genera Aspergillus and Penicillium. Nowadays, there are about 20 species accepted as OTA producers, which are distributed in three phylogenetically related but distinct groups of aspergilli of the subgenus Circumdati and only in [...] Read more.

Ochratoxin A (OTA) producing fungi are members of the genera Aspergillus and Penicillium. Nowadays, there are about 20 species accepted as OTA producers, which are distributed in three phylogenetically related but distinct groups of aspergilli of the subgenus Circumdati and only in two species of the subgenus Penicillium. At the moment, P. verrucosum and P. nordicum are the only OTA producing species accepted in the genus Penicillium. However, during the last century, OTA producers in this genus were classified as P. viridicatum for many years. At present, only some OTA producing species are known to be a potential source of OTA contamination of cereals and certain common foods and beverages such as bread, beer, coffee, dried fruits, grape juice and wine among others. Penicillium verrucosum is the major producer of OTA in cereals such as wheat and barley in temperate and cold climates. Penicillium verrucosum and P. nordicum can be recovered from some dry-cured meat products and some cheeses. Full article

(This article belongs to the Special Issue Ochratoxins)

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Open AccessArticle

Pathological Outcomes in Kidney and Brain in Male Fischer Rats Given Dietary Ochratoxin A, Commencing at One Year of Age

by Peter G. Mantle and Christopher C. Nolan

Toxins 2010, 2(5), 1100-1110; https://doi.org/10.3390/toxins2051100 - 13 May 2010

Cited by 19 | Viewed by 11504

Abstract

Malignant renal carcinoma, manifest in morbid ageing rats, is the striking component of an otherwise silent response after about nine months of exposure to ochratoxin A in the first year of life (daily intake ~100–250 µg/kg body weight). Reasons for the long latency [...] Read more.

Malignant renal carcinoma, manifest in morbid ageing rats, is the striking component of an otherwise silent response after about nine months of exposure to ochratoxin A in the first year of life (daily intake ~100–250 µg/kg body weight). Reasons for the long latency are unclear, as is whether there would be a similar carcinogenic response if toxin exposure started at one year of age. Therefore, 24 male Fischer rats were given 100 µg ochratoxin A as a daily dietary contaminant for 35 weeks from age 50 weeks. Plasma ochratoxin A concentration reached a maximum value of ~8 µg/mL within one month of starting the toxin regimen. No renal carcinomas occurred. Four renal adenomas, two of which were only microscopic, were found among the six rats surviving for 110 weeks. The findings raise new questions about a difference between young adults and mature adults in sensitivity of male rats to the ochratoxin A-induced DNA damage necessary for renal carcinogenesis. A pilot histological study of perfuse-fixed brains of the toxin-treated rats showed no gross abnormalities, correlating with the consistent absence of behavioral or neurological disorders from chronic ochratoxin A exposure regimens in the range 100–250 µg/kg/day during the second half of life. Reasoned questioning concerning ochratoxin A as a neurotoxic mycotoxin is made. Full article

(This article belongs to the Special Issue Ochratoxins)

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Open AccessReview

Biodegradation of Ochratoxin A for Food and Feed Decontamination

by Luís Abrunhosa, Robert R.M. Paterson and Armando Venâncio

Toxins 2010, 2(5), 1078-1099; https://doi.org/10.3390/toxins2051078 - 13 May 2010

Cited by 184 | Viewed by 16742

Abstract

Ochratoxin A (OTA) is one of the most important mycotoxins that is found in food and feed products. It has proven toxic properties, being primarily known for its nephrotoxicity and carcinogenicity to certain animal species. OTA is produced by several species of Aspergillus [...] Read more.

Ochratoxin A (OTA) is one of the most important mycotoxins that is found in food and feed products. It has proven toxic properties, being primarily known for its nephrotoxicity and carcinogenicity to certain animal species. OTA is produced by several species of Aspergillus and Penicillium that can be found in a wide variety of agricultural products, which makes the presence of OTA in these products common. Many countries have statutory limits for OTA, and concentrations need to be reduced to as low as technologically possible in food and feed. The most important measures to be taken to control OTA are preventive in order to avoid fungal growth and OTA production. However, these measures are difficult to implement in all cases with the consequence of OTA remaining in agricultural commodities. Remediation processes are often used to eliminate, reduce or avoid the toxic effects of OTA. Biological methods have been considered increasingly as an alternative to physical and chemical treatments. However, examples of practical applications are infrequent. This review will focus on the (i) known microorganisms and enzymes that are able to biodegrade OTA; (ii) mode of action of biodegradation and (iii) current applications. A critical discussion about the technical applicability of these strategies is presented. Full article

(This article belongs to the Special Issue Ochratoxins)

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Open AccessReview

Ochratoxins in Feed, a Risk for Animal and Human Health: Control Strategies

by Muzaffer Denli and Jose F. Perez

Toxins 2010, 2(5), 1065-1077; https://doi.org/10.3390/toxins2051065 - 13 May 2010

Cited by 73 | Viewed by 11196

Abstract

Ochratoxin A (OTA) has been shown to be a potent nephrotoxic, hepatotoxic, and teratogenic compound. In farm animals, the intake of feed contaminated with OTA affects animal health and productivity, and may result in the presence of OTA in the animal products. Strategies [...] Read more.

Ochratoxin A (OTA) has been shown to be a potent nephrotoxic, hepatotoxic, and teratogenic compound. In farm animals, the intake of feed contaminated with OTA affects animal health and productivity, and may result in the presence of OTA in the animal products. Strategies for the control of OTA in food products require early identification and elimination of contaminated commodities from the food chain. However, current analytical protocols may fail to identify contaminated products, especially in animal feed. The present paper discusses the impact of OTA on human and animal health, with special emphasis on the potential risks of OTA residue in animal products, and control strategies applied in the feed industry. Full article

(This article belongs to the Special Issue Ochratoxins)

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Open AccessArticle

Occurrence of Ochratoxin A in Southern Spanish Generous Wines under the Denomination of Origin “Jerez-Xérès-Sherry and ‘Manzanilla’ Sanlúcar de Barrameda”

by Mª Teresa Murillo-Arbizu, Susana Amézqueta, Elena González-Peñas and Adela López De Cerain

Toxins 2010, 2(5), 1054-1064; https://doi.org/10.3390/toxins2051054 - 12 May 2010

Cited by 14 | Viewed by 10044

Abstract

The mycotoxin ochratoxin A (OTA) has toxic effects in animals; the most relevant of them is nephrotoxicity. OTA has also been classified as a possible carcinogen for humans (group 2B) by the International Agency for Research on Cancer (IARC). Therefore, exposure to OTA [...] Read more.

The mycotoxin ochratoxin A (OTA) has toxic effects in animals; the most relevant of them is nephrotoxicity. OTA has also been classified as a possible carcinogen for humans (group 2B) by the International Agency for Research on Cancer (IARC). Therefore, exposure to OTA through contaminated food can represent health impairment to humans. The maximum permitted level for this mycotoxin in wine is 2.0 mg/L. The presence of OTA in Spanish wines produced using the traditional methods under the Denomination of Origin “Jerez-Xérès-Sherry and manzanilla Sanlúcar de Barrameda” was evaluated by a High performance Liquid Chromatography method with fluorescence detection and immunoaffinity column purification. A recovery of 95.4% and a limit of detection and quantification of 0.009 mg/L and 0.02 mg/L respectively, were achieved. In manzanilla, fino, amontillado and oloroso wine, the mean OTA values were 0.042, 0.044, 0.144, and 0.319 mg/L, respectively. These levels are not different from other data given in the reference literature on white wines, although fino and manzanilla wines have very low OTA levels. Full article

(This article belongs to the Special Issue Ochratoxins)

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Open AccessReview

Consequences and Utility of the Zinc-Dependent Metalloprotease Activity of Anthrax Lethal Toxin

by Jennifer Bromberg-White, Chih-Shia Lee and Nicholas Duesbery

Toxins 2010, 2(5), 1038-1053; https://doi.org/10.3390/toxins2051038 - 11 May 2010

Cited by 18 | Viewed by 10839

Abstract

Anthrax is caused by the gram-positive bacterium Bacillus anthracis. The pathogenesis of this disease is dependent on the presence of two binary toxins, edema toxin (EdTx) and lethal toxin (LeTx). LeTx, the major virulence factor contributing to anthrax, contains the effector moiety [...] Read more.

Anthrax is caused by the gram-positive bacterium Bacillus anthracis. The pathogenesis of this disease is dependent on the presence of two binary toxins, edema toxin (EdTx) and lethal toxin (LeTx). LeTx, the major virulence factor contributing to anthrax, contains the effector moiety lethal factor (LF), a zinc-dependent metalloprotease specific for targeting mitogen-activated protein kinase kinases. This review will focus on the protease-specific activity and function of LF, and will include a discussion on the implications and consequences of this activity, both in terms of anthrax disease, and how this activity can be exploited to gain insight into other pathologic conditions. Full article

(This article belongs to the Special Issue Protein Toxins as Proteases)

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Open AccessReview

A Review on Toxic and Harmful Algae in Greek Coastal Waters (E. Mediterranean Sea)

by Lydia Ignatiades and Olympia Gotsis-Skretas

Toxins 2010, 2(5), 1019-1037; https://doi.org/10.3390/toxins2051019 - 11 May 2010

Cited by 78 | Viewed by 14527

Abstract

The Greek coastal waters are subjected to harmful algal bloom (HAB) phenomena due to the occurrence of species characterized as toxic (TX), potentially toxic (PT), and non-toxic, high biomass (HB) producers causing harm at multiple levels. The total number of (TX), (PT) and [...] Read more.

The Greek coastal waters are subjected to harmful algal bloom (HAB) phenomena due to the occurrence of species characterized as toxic (TX), potentially toxic (PT), and non-toxic, high biomass (HB) producers causing harm at multiple levels. The total number of (TX), (PT) and (HB) algae reported in this work are 61, but only 16 species have been associated with the occurrence of important HABs causing damage in the marine biota and the water quality. These phenomena are sporadic in time, space and recurrence of the causative species, and are related to the anthropogenically-induced eutrophication conditions prevailing in the investigated areas. Full article

(This article belongs to the Special Issue Algal Toxins)

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Open AccessReview

Toxin-Specific Antibodies for the Treatment of Clostridium difficile: Current Status and Future Perspectives

by Greg Hussack and Jamshid Tanha

Toxins 2010, 2(5), 998-1018; https://doi.org/10.3390/toxins2050998 - 7 May 2010

Cited by 33 | Viewed by 13232

Abstract

Therapeutic agents targeting bacterial virulence factors are gaining interest as non-antibiotic alternatives for the treatment of infectious diseases. Clostridium difficile is a Gram-positive pathogen that produces two primary virulence factors, enterotoxins A and B (TcdA and TcdB), which are responsible for Clostridium difficile [...] Read more.

Therapeutic agents targeting bacterial virulence factors are gaining interest as non-antibiotic alternatives for the treatment of infectious diseases. Clostridium difficile is a Gram-positive pathogen that produces two primary virulence factors, enterotoxins A and B (TcdA and TcdB), which are responsible for Clostridium difficile-associated disease (CDAD) and are targets for CDAD therapy. Antibodies specific for TcdA and TcdB have been shown to effectively treat CDAD and prevent disease relapse in animal models and in humans. This review summarizes the various toxin-specific antibody formats and strategies under development, and discusses future directions for CDAD immunotherapy, including the use of engineered antibody fragments with robust biophysical properties for systemic and oral delivery. Full article

(This article belongs to the Special Issue Enterotoxins)

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Open AccessReview

The Zinc-Dependent Protease Activity of the Botulinum Neurotoxins

by Frank J. Lebeda, Regina Z. Cer, Uma Mudunuri, Robert Stephens, Bal Ram Singh and Michael Adler

Toxins 2010, 2(5), 978-997; https://doi.org/10.3390/toxins2050978 - 7 May 2010

Cited by 23 | Viewed by 13358

Abstract

The botulinum neurotoxins (BoNT, serotypes A-G) are some of the most toxic proteins known and are the causative agents of botulism. Following exposure, the neurotoxin binds and enters peripheral cholinergic nerve endings and specifically and selectively cleaves one or more SNARE proteins to [...] Read more.

The botulinum neurotoxins (BoNT, serotypes A-G) are some of the most toxic proteins known and are the causative agents of botulism. Following exposure, the neurotoxin binds and enters peripheral cholinergic nerve endings and specifically and selectively cleaves one or more SNARE proteins to produce flaccid paralysis. This review centers on the kinetics of the Zn-dependent proteolytic activities of these neurotoxins, and briefly describes inhibitors, activators and factors underlying persistence of toxin action. Some of the structural, enzymatic and inhibitor data that are discussed here are available at the botulinum neurotoxin resource, BotDB (http://botdb.abcc.ncifcrf.gov). Full article

(This article belongs to the Special Issue Protein Toxins as Proteases)

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Open AccessReview

Autoproteolytic Activation of Bacterial Toxins

by Aimee Shen

Toxins 2010, 2(5), 963-977; https://doi.org/10.3390/toxins2050963 - 6 May 2010

Cited by 18 | Viewed by 11545

Abstract

Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD) in Multifunctional Autoprocessing RTX-like (MARTX) and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and [...] Read more.

Protease domains within toxins typically act as the primary effector domain within target cells. By contrast, the primary function of the cysteine protease domain (CPD) in Multifunctional Autoprocessing RTX-like (MARTX) and Clostridium sp. glucosylating toxin families is to proteolytically cleave the toxin and release its cognate effector domains. The CPD becomes activated upon binding to the eukaryotic-specific small molecule, inositol hexakisphosphate (InsP₆), which is found abundantly in the eukaryotic cytosol. This property allows the CPD to spatially and temporally regulate toxin activation, making it a prime candidate for developing anti-toxin therapeutics. In this review, we summarize recent findings related to defining the regulation of toxin function by the CPD and the development of inhibitors to prevent CPD-mediated activation of bacterial toxins. Full article

(This article belongs to the Special Issue Protein Toxins as Proteases)

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Open AccessReview

The Role of Lymphostatin/EHEC Factor for Adherence-1 in the Pathogenesis of Gram Negative Infection

by Jan-Michael A. Klapproth

Toxins 2010, 2(5), 954-962; https://doi.org/10.3390/toxins2050954 - 5 May 2010

Cited by 7 | Viewed by 8804

Abstract

Lymphostatin/EHEC factor for adherence-1 is a novel large toxin represented in various Gram negative bacteria, highly associated with the development of infectious diarrhea and hemolytic uremic syndrome. In vitro and in vivo experiments identified lymphostatin/EFA-1 as a toxin with a central role in [...] Read more.

Lymphostatin/EHEC factor for adherence-1 is a novel large toxin represented in various Gram negative bacteria, highly associated with the development of infectious diarrhea and hemolytic uremic syndrome. In vitro and in vivo experiments identified lymphostatin/EFA-1 as a toxin with a central role in the pathogenesis of Gram negative bacteria, responsible for bacterial adhesion, intestinal colonization, immunosuppression, and disruption of gut epithelial barrier function. Full article

(This article belongs to the Special Issue Enterotoxins)

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Open AccessReview

Proteases as Insecticidal Agents

by Robert L. Harrison and Bryony C. Bonning

Toxins 2010, 2(5), 935-953; https://doi.org/10.3390/toxins2050935 - 5 May 2010

Cited by 82 | Viewed by 17216

Abstract

Proteases from a variety of sources (viruses, bacteria, fungi, plants, and insects) have toxicity towards insects. Some of these insecticidal proteases evolved as venom components, herbivore resistance factors, or microbial pathogenicity factors, while other proteases play roles in insect development or digestion, but [...] Read more.

Proteases from a variety of sources (viruses, bacteria, fungi, plants, and insects) have toxicity towards insects. Some of these insecticidal proteases evolved as venom components, herbivore resistance factors, or microbial pathogenicity factors, while other proteases play roles in insect development or digestion, but exert an insecticidal effect when over-expressed from genetically engineered plants or microbial pathogens. Many of these proteases are cysteine proteases, although insect-toxic metalloproteases and serine proteases have also been examined. The sites of protease toxic activity range from the insect midgut to the hemocoel (body cavity) to the cuticle. This review discusses these insecticidal proteases along with their evaluation and use as potential pesticides. Full article

(This article belongs to the Special Issue Protein Toxins as Proteases)

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Toxins, Volume 2, Issue 5 (May 2010) – 16 articles , Pages 935-1178

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