Toxins

2256 KiB

Open AccessReview

Clostridium perfringens Iota-Toxin: Structure and Function

by Jun Sakurai, Masahiro Nagahama, Masataka Oda, Hideaki Tsuge and Keiko Kobayashi

Toxins 2009, 1(2), 208-228; https://doi.org/10.3390/toxins1020208 - 23 Dec 2009

Cited by 60 | Viewed by 18140

Clostridium perfringens iota-toxin is composed of the enzyme component (Ia) and the binding component (Ib). Ib binds to receptor on targeted cells and translocates Ia into the cytosol of the cells. Ia ADP-ribosylates actin, resulting in cell rounding and death. Comparisons of the [...] Read more.

Clostridium perfringens iota-toxin is composed of the enzyme component (Ia) and the binding component (Ib). Ib binds to receptor on targeted cells and translocates Ia into the cytosol of the cells. Ia ADP-ribosylates actin, resulting in cell rounding and death. Comparisons of the deduced amino acid sequence from the gene and three-dimensional structure of Ia with those of ADP-ribosylating toxins (ARTs) suggests that there is striking structural similarity among these toxins. Our objectives are to review the recent advances in the character, structure-function, and the mode of action of iota-toxin by consideration of the findings about ARTs. Full article

(This article belongs to the Special Issue Bacterial Protein Toxins)

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309 KiB

Open AccessReview

Fluorescence Polarization Immunoassay of Mycotoxins: A Review

by Chris Maragos

Toxins 2009, 1(2), 196-207; https://doi.org/10.3390/toxins1020196 - 10 Dec 2009

Cited by 56 | Viewed by 18209

Abstract

Immunoassays are routinely used in the screening of commodities and foods for fungal toxins (mycotoxins). Demands to increase speed and lower costs have lead to continued improvements in such assays. Because many reported mycotoxins are low molecular weight (below 1 kDa), immunoassays for [...] Read more.

Immunoassays are routinely used in the screening of commodities and foods for fungal toxins (mycotoxins). Demands to increase speed and lower costs have lead to continued improvements in such assays. Because many reported mycotoxins are low molecular weight (below 1 kDa), immunoassays for their detection have generally been constructed in competitive heterogeneous formats. An exception is fluorescence polarization immunoassay (FPIA), a homogeneous format that does not require the separation of bound and free labels (tracer). The potential for rapid, solution phase, immunoassays has been realized in the development of FPIA for many of the major groups of mycotoxins, including aflatoxins, fumonisins, group B trichothecenes (primarily deoxynivalenol), ochratoxin A, and zearalenone. This review describes the basic principles of FPIA and summarizes recent research in this area with regard to mycotoxins. Full article

(This article belongs to the Special Issue Advances in Mycotoxin Research)

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104 KiB

Open AccessCommunication

Preparation of an In-House Reference Material Containing Fumonisins in Thai Rice and Matrix Extension of the Analytical Method for Japanese Rice

by Norhafniza Awaludin, Reiko Nagata, Tomomi Kawasaki and Masayo Kushiro

Toxins 2009, 1(2), 188-195; https://doi.org/10.3390/toxins1020188 - 8 Dec 2009

Cited by 4 | Viewed by 9431

Abstract

Mycotoxin contamination in rice is less reported, compared to that in wheat or maize, however, some Fusarium fungi occasionally infect rice in the paddy field. Fumonisins are mycotoxins mainly produced by Fusarium verticillioides, which often ruins maize. Rice adherent fungus Gibberella fujikuroi [...] Read more.

Mycotoxin contamination in rice is less reported, compared to that in wheat or maize, however, some Fusarium fungi occasionally infect rice in the paddy field. Fumonisins are mycotoxins mainly produced by Fusarium verticillioides, which often ruins maize. Rice adherent fungus Gibberella fujikuroi is taxonomically near to F. verticillioides, and there are sporadic reports of fumonisin contamination in rice from Asia, Europe and the United States. Therefore, there exists the potential risk of fumonisin contamination in rice as well as the need for the validated analytical method for fumonisins in rice. Although both natural and spiked reference materials are available for some Fusarium mycotoxins in matrices of wheat and maize, there are no reference materials for Fusarium mycotoxins in rice. In this study, we have developed a method for the preparation of a reference material containing fumonisins in Thai rice. A ShakeMaster grinding machine was used for the preparation of a mixed material of blank Thai rice and F. verticillioides-infected Thai rice. The homogeneity of the mixed material was confirmed by one-way analysis of variance, which led this material to serve as an in-house reference material. Using this reference material, several procedures to extract fumonisins from Thai rice were compared. Accordingly, we proved the applicability of an effective extraction procedure for the determination of fumonisins in Japanese rice. Full article

(This article belongs to the Special Issue Advances in Mycotoxin Research)

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613 KiB

Open AccessArticle

Functional Analysis of a Putative Dothistromin Toxin MFS Transporter Gene

by Rosie E. Bradshaw, Zhilun Feng, Arne Schwelm, Yongzhi Yang and Shuguang Zhang

Toxins 2009, 1(2), 173-187; https://doi.org/10.3390/toxins1020173 - 8 Dec 2009

Cited by 9 | Viewed by 10365

Abstract

Dothistromin is a non-host selective toxin produced by the pine needle pathogen Dothistroma septosporum. Dothistromin is not required for pathogenicity, but may have a role in competition and niche protection. To determine how D. septosporum tolerates its own toxin, a putative dothistromin [...] Read more.

Dothistromin is a non-host selective toxin produced by the pine needle pathogen Dothistroma septosporum. Dothistromin is not required for pathogenicity, but may have a role in competition and niche protection. To determine how D. septosporum tolerates its own toxin, a putative dothistromin transporter, DotC, was investigated. Studies with mutants lacking a functional dotC gene, overproducing DotC, or with a DotC-GFP fusion gene, did not provide conclusive evidence of a role in dothistromin efflux. The mutants revealed a major effect of DotC on dothistromin biosynthesis but were resistant to exogenous dothistromin. Intracellular localization studies suggest that compartmentalization may be important for dothistromin tolerance. Full article

(This article belongs to the Special Issue Advances in Mycotoxin Research)

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497 KiB

Open AccessArticle

Isolation and Chemical Characterization of a Toxin Isolated from the Venom of the Sea Snake, Hydrophis torquatus aagardi

by Masaya Nagamizu, Yumiko Komori, Kei-ichi Uchiya, Toshiaki Nikai and Anthony T. Tu

Toxins 2009, 1(2), 162-172; https://doi.org/10.3390/toxins1020162 - 8 Dec 2009

Cited by 7 | Viewed by 9743

Abstract

Sea snakes (family: Hydrophiidae) are serpents found in the coastal areas of the Indian and Pacific Oceans. There are two subfamilies in Hydrophiidae: Hydrophiinae and Laticaudinae. A toxin, aagardi toxin, was isolated from the venom of the Hydrophiinae snake, Hydrophis torquatus aagardi and [...] Read more.

Sea snakes (family: Hydrophiidae) are serpents found in the coastal areas of the Indian and Pacific Oceans. There are two subfamilies in Hydrophiidae: Hydrophiinae and Laticaudinae. A toxin, aagardi toxin, was isolated from the venom of the Hydrophiinae snake, Hydrophis torquatus aagardi and its chemical properties such as molecular weight, isoelectric point, importance of disulfide bonds, lack of enzymatic activity and amino acid sequence were determined. The amino acid sequence indicated a close relationship to the primary structure of other Hydrophiinae toxins and a significant difference from Laticaudinae toxins, confirming that primary toxin structure is closely related to sea snake phylogenecity. Full article

(This article belongs to the Special Issue Neurotoxins of Biological Origin)

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682 KiB

Open AccessArticle

Comparison of Sea Snake (Hydrophiidae) Neurotoxin to Cobra (Naja) Neurotoxin

by Yumiko Komori, Masaya Nagamizu, Kei-ichi Uchiya, Toshiaki Nikai and Anthony T. Tu

Toxins 2009, 1(2), 151-161; https://doi.org/10.3390/toxins1020151 - 3 Dec 2009

Cited by 3 | Viewed by 11175

Abstract

Both sea snakes and cobras have venoms containing postsynaptic neurotoxins. Comparison of the primary structures indicates many similarities, especially the positions of the four disulfide bonds. However, detailed examination reveals differences in several amino acid residues. Amino acid sequences of sea snake neurotoxins [...] Read more.

Both sea snakes and cobras have venoms containing postsynaptic neurotoxins. Comparison of the primary structures indicates many similarities, especially the positions of the four disulfide bonds. However, detailed examination reveals differences in several amino acid residues. Amino acid sequences of sea snake neurotoxins were determined, and then compared to cobra neurotoxins by computer modeling. This allowed for easy comparison of the similarities and differences between the two types of postsynaptic neurotoxins. Comparison of computer models for the toxins of sea snakes and cobra will reveal the three dimensional difference of the toxins much clearer than the amino acid sequence alone. Full article

(This article belongs to the Special Issue Neurotoxins of Biological Origin)

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289 KiB

Open AccessArticle

Determination of the Biological Activity and Structure Activity Relationships of Drugs Based on the Highly Cytotoxic Duocarmycins and CC-1065

by Lutz F. Tietze, Birgit Krewer, J. Marian Von Hof, Holm Frauendorf and Ingrid Schuberth

Toxins 2009, 1(2), 134-150; https://doi.org/10.3390/toxins1020134 - 2 Dec 2009

Cited by 19 | Viewed by 13926

Abstract

The natural antibiotics CC-1065 and the duocarmycins are highly cytotoxic compounds which however are not suitable for cancer therapy due to their general toxicity. We have developed glycosidic prodrugs of seco-analogues of these antibiotics for a selective cancer therapy using conjugates of [...] Read more.

The natural antibiotics CC-1065 and the duocarmycins are highly cytotoxic compounds which however are not suitable for cancer therapy due to their general toxicity. We have developed glycosidic prodrugs of seco-analogues of these antibiotics for a selective cancer therapy using conjugates of glycohydrolases and tumour-selective monoclonal antibodies for the liberation of the drugs from the prodrugs predominantly at the tumour site. For the determination of structure activity relationships of the different seco-drugs, experiments addressing their interaction with synthetic DNA were performed. Using electrospray mass spectrometry and high performance liquid chromatography, the experiments revealed a correlation of the stability of these drugs with their cytotoxicity in cell culture investigations. Furthermore, it was shown that the drugs bind to AT-rich regions of double-stranded DNA and the more cytotoxic drugs induce DNA fragmentation at room temperature in several of the selected DNA double-strands. Finally, an explanation for the very high cytotoxicity of CC-1065, the duocarmycins and analogous drugs is given. Full article

(This article belongs to the Special Issue Feature Papers)

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491 KiB

Open AccessReview

Actin Crosslinking Toxins of Gram-Negative Bacteria

by Karla J. F. Satchell

Toxins 2009, 1(2), 123-133; https://doi.org/10.3390/toxins1020123 - 1 Dec 2009

Cited by 22 | Viewed by 10842

Abstract

Actin crosslinking toxins produced by Gram-negative bacteria represent a small but unique class of bacterial protein toxins. For each of these toxins, a discrete actin crosslinking domain (ACD) that is a distant member of the ATP-dependent glutamine synthetase family of protein ligases is [...] Read more.

Actin crosslinking toxins produced by Gram-negative bacteria represent a small but unique class of bacterial protein toxins. For each of these toxins, a discrete actin crosslinking domain (ACD) that is a distant member of the ATP-dependent glutamine synthetase family of protein ligases is translocated to the eukaryotic cell cytosol. This domain then incorporates a glutamate-lysine crosslink between actin monomers, resulting in destruction of the actin cytoskeleton. Recent studies argue that the function of these toxins during infection is not destruction of epithelial layers, but rather may specifically target phagocytic cells to promote survival of bacteria after the onset of innate immune defenses. This review will summarize key experiments performed over the past 10 years to reveal the function of these toxins. Full article

(This article belongs to the Special Issue Bacterial Protein Toxins)

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152 KiB

Open AccessReview

CyanoHAB Occurrence and Water Irrigation Cyanotoxin Contamination: Ecological Impacts and Potential Health Risks

by Sana Saqrane and Brahim Oudra

Toxins 2009, 1(2), 113-122; https://doi.org/10.3390/toxins1020113 - 25 Nov 2009

Cited by 39 | Viewed by 11254

Abstract

The world-wide occurrence of harmful cyanobacteria blooms “CyanoHAB” in fresh and brackish waters creates problems for all life forms. During CyanoHAB events, toxic cyanobacteria produce cyanotoxins at high levels that can cause chronic and sub-chronic toxicities to animals, plants and humans. [...] Read more.

The world-wide occurrence of harmful cyanobacteria blooms “CyanoHAB” in fresh and brackish waters creates problems for all life forms. During CyanoHAB events, toxic cyanobacteria produce cyanotoxins at high levels that can cause chronic and sub-chronic toxicities to animals, plants and humans. Cyanotoxicity in eukaryotes has been mainly focused on animals, but during these last years, data, related to cyanotoxin (mainly microcystins, MCs) impact on both aquatic and terrestrials crop plants irrigated by water containing these toxins, have become more and more available. This last cited fact is gaining importance since plants could in a direct or indirect manner contribute to cyanotoxin transfer through the food chain, and thus constitute a potent health risk source. The use of this contaminated irrigation water can also have an economical impact which appears by a reduction of the germination rate of seeds, and alteration of the quality and the productivity of crop plants. The main objective of this work was to discuss the eventual phytotoxicity of cyanotoxins (microcystins) as the major agricultural impacts induced by the use of contaminated water for plant irrigation. These investigations confirm the harmful effects (ecological, eco-physiological, socio-economical and sanitary risk) of dissolved MCs on agricultural plants. Thus, cyanotoxin phytotoxicity strongly suggests a need for the surveillance of CyanoHAB and the monitoring of water irrigation quality as well as for drinking water. Full article

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133 KiB

Open AccessArticle

Asp Viper (Vipera aspis) Envenomation: Experience of the Marseille Poison Centre from 1996 to 2008

by Luc De Haro, Mathieu Glaizal, Lucia Tichadou, Ingrid Blanc-Brisset and Maryvonne Hayek-Lanthois

Toxins 2009, 1(2), 100-112; https://doi.org/10.3390/toxins1020100 - 24 Nov 2009

Cited by 55 | Viewed by 12202

Abstract

A retrospective case review study of viper envenomations collected by the Marseille’s Poison Centre between 1996 and 2008 was performed. Results: 174 cases were studied (52 grade 1 = G1, 90 G2 and 32 G3). G1 patients received symptomatic treatments (average hospital stay [...] Read more.

A retrospective case review study of viper envenomations collected by the Marseille’s Poison Centre between 1996 and 2008 was performed. Results: 174 cases were studied (52 grade 1 = G1, 90 G2 and 32 G3). G1 patients received symptomatic treatments (average hospital stay 0.96 day). One hundred and six (106) of the G2/G3 patients were treated with the antivenom Viperfav* (2.1+/-0.9 days in hospital), while 15 of them received symptomatic treatments only (plus one immediate death) (8.1+/-4 days in hospital, 2 of them died). The hospital stay was significantly reduced in the antivenom treated group (p < 0.001), and none of the 106 antivenom treated patients had immediate (anaphylaxis) or delayed (serum sickness) allergic reactions. Conclusion: Viperfav* antivenom was safe and effective for treating asp viper venom-induced toxicity. Full article

(This article belongs to the Special Issue Animal Venoms)

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512 KiB

Open AccessReview

Cyclopiazonic Acid Biosynthesis of Aspergillus flavus and Aspergillus oryzae

by Perng-Kuang Chang, Kenneth C. Ehrlich and Isao Fujii

Toxins 2009, 1(2), 74-99; https://doi.org/10.3390/toxins1020074 - 6 Nov 2009

Cited by 116 | Viewed by 17551

Abstract

Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. [...] Read more.

Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines what is currently known about the toxicity of CPA to animals and humans, both by itself or in combination with other mycotoxins. The review also discusses CPA biosynthesis and the genetic diversity of CPA production in A. flavus/oryzae populations. Full article

(This article belongs to the Special Issue Feature Papers)

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351 KiB

Open AccessArticle

Immune Response to Chlamydophila abortus POMP91B Protein in the Context of Different Pathogen Associated Molecular Patterns (PAMP); Role of Antigen in the Orientation of Immune Response

by Vincent Le Moigne, Georges Robreau and Wahib Mahana

Toxins 2009, 1(2), 59-73; https://doi.org/10.3390/toxins1020059 - 13 Oct 2009

Viewed by 10149

Abstract

In a previous study, we used bacterial flagellin to deliver antigens such as p27 of Mycobacterium tuberculosis to a host immune system and obtained a potent Th1 responsecompared to those obtained with Freund’s adjuvant and DNA immunization. In the current study, using a [...] Read more.

In a previous study, we used bacterial flagellin to deliver antigens such as p27 of Mycobacterium tuberculosis to a host immune system and obtained a potent Th1 responsecompared to those obtained with Freund’s adjuvant and DNA immunization. In the current study, using a POMP91B antigen of Chlamydophila abortus, a human and animal pathogen, as a model, we found that this antigen is unable to promote Th1 response. However, this antigen, unlike others, was able to induce a good Th2 response and IL-4 production after immunization by recombinant protein in Freund’s adjuvant or in phosphate buffered saline. Our results suggest that immune response is not only dependent on the immunization adjuvant, but also dependent on the nature of antigen used. Full article

(This article belongs to the Collection Toxicity and Therapeutic Interventions in the Immune System)

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Toxins, Volume 1, Issue 2 (December 2009) – 12 articles , Pages 59-228

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