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Natural Toxins

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products Chemistry".

Deadline for manuscript submissions: closed (10 March 2016) | Viewed by 116460

Special Issue Editor


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Guest Editor
Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Health and Food Sciences Precinct, Coopers Plains, QLD 4108, Australia
Interests: natural toxins; toxin characterization; phytotoxins; analytical methods; toxin degradation; food safety
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The Special Issue on “Natural Toxins” focuses on harmful compounds which have a natural origin and have the potential to impact human or animal health (or both). Natural toxins can be produced by fungi (mycotoxins), algae (phycotoxins), bacteria (bacterial toxins), plants (phytoxins), and animals (zootoxins). The presence of natural toxins as bio-contaminants or even integral components in food and feed can contribute to the occurrence of human or animal disease. Whilst some toxins are acutely toxic, others are non-acute and toxicity is only manifest with excessive or prolonged exposure. Putting the risk into perspective it is often quoted that “only the dose makes the poison” (Paracelsus 16th Century). There has been sustained interest of the scientific community in natural toxins, in understanding their biological effects, determining their chemical composition, and developing methods to detect and control their presence. Mycotoxins, particularly, have been the focus of risk assessments, and regulations controlling the presence of mycotoxins in a range of commodities have been established across many countries. These developments require the establishment of high throughput methods, such as LC-MS, with increasingly lower limits of detection, and have led to an ever-increasing interest in management strategies and treatments to control the formation of mycotoxin either in the field or post-harvest. Plant toxins also cause major economic losses particularly to livestock producers and can variously impact on the general populous. The understanding and regulation of plant toxins are less developed, and is limited by the immense diversity of chemical structure of such toxins and the availability of standards. Impacts of plant toxins are not limited to grazing livestock but can be carried through the food chain. Pyrrolizidine alkaloids for example have generated significant interest in recent years with considerable concern relating to their presence in herbal treatments and also their potential contamination of honey through pollen transfer.

In conclusion, this Special Issue should review all the aspects concerning natural toxins, focusing on both chemical identification and analysis of these toxins and also the biochemical, molecular, and clinical effects that these compounds may exert.

Dr. Mary Fletcher
Guest Editor

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Keywords

  • mycotoxins
  • phycotoxins
  • bacterial toxins
  • phytoxins
  • poisonous plants
  • zootoxins
  • toxicology
  • residue analysis

Published Papers (13 papers)

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Research

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1156 KiB  
Article
Chemical Synthesis of Deoxynivalenol-3-β-d-[13C6]-glucoside and Application in Stable Isotope Dilution Assays
by Katharina Habler, Oliver Frank and Michael Rychlik
Molecules 2016, 21(7), 838; https://doi.org/10.3390/molecules21070838 - 27 Jun 2016
Cited by 10 | Viewed by 6115
Abstract
Modified mycotoxins have been gaining importance in recent years and present a certain challenge in LC-MS/MS analysis. Due to the previous lack of a labeled isotopologue of the modified mycotoxin deoxynivalenol-3-glucoside, in our study we synthesized the first 13C-labeled internal standard. Therefore, [...] Read more.
Modified mycotoxins have been gaining importance in recent years and present a certain challenge in LC-MS/MS analysis. Due to the previous lack of a labeled isotopologue of the modified mycotoxin deoxynivalenol-3-glucoside, in our study we synthesized the first 13C-labeled internal standard. Therefore, we used the Königs-Knorr method to synthesize deoxynivalenol-3-β-d-[13C6]-glucoside originated from unlabeled deoxynivalenol and [13C6]-labeled glucose. Using the synthesized isotopically-labeled standard deoxynivalenol-3-β-d-[13C6]-glucoside and the purchased labeled standard [13C15]-deoxynivalenol, a stable isotope dilution LC-MS/MS method was firstly developed for deoxynivalenol-3-glucoside and deoxynivalenol in beer. The preparation and purification of beer samples was based on a solid phase extraction. The validation data of the newly developed method gave satisfying results. Intra- and interday precision studies revealed relative standard deviations below 0.5% and 7%, respectively. The recoveries ranged for both analytes between 97% and 112%. The stable isotope dilution assay was applied to various beer samples from four different countries. In summary, deoxynivalenol-3-glucoside and deoxynivalenol mostly appeared together in varying molar ratios but were quantified in rather low contents in the investigated beers. Full article
(This article belongs to the Special Issue Natural Toxins)
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4095 KiB  
Article
Two Trichothecene Mycotoxins from Myrothecium roridum Induce Apoptosis of HepG-2 Cells via Caspase Activation and Disruption of Mitochondrial Membrane Potential
by Wei Ye, Yuchan Chen, Haohua Li, Weimin Zhang, Hongxin Liu, Zhanghua Sun, Taomei Liu and Saini Li
Molecules 2016, 21(6), 781; https://doi.org/10.3390/molecules21060781 - 17 Jun 2016
Cited by 16 | Viewed by 5165
Abstract
Trichothecene mycotoxins are a type of sesquiterpenoid produced by various kinds of plantpathogenic fungi. In this study, two trichothecene toxins, namely, a novel cytotoxic epiroridin acid and a known trichothecene, mytoxin B, were isolated from the endophytic fungus Myrothecium roridum derived from the [...] Read more.
Trichothecene mycotoxins are a type of sesquiterpenoid produced by various kinds of plantpathogenic fungi. In this study, two trichothecene toxins, namely, a novel cytotoxic epiroridin acid and a known trichothecene, mytoxin B, were isolated from the endophytic fungus Myrothecium roridum derived from the medicinal plant Pogostemon cablin. The two trichothecene mytoxins were confirmed to induce the apoptosis of HepG-2 cells by cytomorphology inspection, DNA fragmentation detection, and flow cytometry assay. The cytotoxic mechanisms of the two mycotoxins were investigated by quantitative real time polymerase chain reaction, western blot, and detection of mitochondrial membrane potential. The results showed that the two trichothecene mycotoxins induced the apoptosis of cancer cell HepG-2 via activation of caspase-9 and caspase-3, up-regulation of bax gene expression, down-regulation of bcl-2 gene expression, and disruption of the mitochondrial membrane potential of the HepG-2 cell. This study is the first to report on the cytotoxic mechanism of trichothecene mycotoxins from M. roridum. This study provides new clues for the development of attenuated trichothecene toxins in future treatment of liver cancer. Full article
(This article belongs to the Special Issue Natural Toxins)
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1801 KiB  
Article
Ptaquiloside in Irish Bracken Ferns and Receiving Waters, with Implications for Land Managers
by Connie O’Driscoll, Carmel Ramwell, Brendan Harhen, Liam Morrison, Frederik Clauson-Kaas, Hans Christian B. Hansen, Graeme Campbell, Jerome Sheahan, Bruce Misstear and Liwen Xiao
Molecules 2016, 21(5), 543; https://doi.org/10.3390/molecules21050543 - 26 Apr 2016
Cited by 27 | Viewed by 7778
Abstract
Ptaquiloside, along with other natural phytotoxins, is receiving increased attention from scientists and land use managers. There is an urgent need to increase empirical evidence to understand the scale of phytotoxin mobilisation and potential to enter into the environment. In this study the [...] Read more.
Ptaquiloside, along with other natural phytotoxins, is receiving increased attention from scientists and land use managers. There is an urgent need to increase empirical evidence to understand the scale of phytotoxin mobilisation and potential to enter into the environment. In this study the risk of ptaquiloside to drinking water was assessed by quantifying ptaquiloside in the receiving waters at three drinking water abstraction sites across Ireland and in bracken fronds surrounding the abstraction sites. We also investigated the impact of different management regimes (spraying, cutting and rolling) on ptaquiloside concentrations at plot-scale in six locations in Northern Ireland, UK. Ptaquiloside concentrations were determined using recent advances in the use of LC-MS for the detection and quantification of ptaquiloside. The results indicate that ptaquiloside is present in bracken stands surrounding drinking water abstractions in Ireland, and ptaquiloside concentrations were also observed in the receiving waters. Furthermore, spraying was found to be the most effective bracken management regime observed in terms of reducing ptaquiloside load. Increased awareness is vital on the implications of managing land with extensive bracken stands. Full article
(This article belongs to the Special Issue Natural Toxins)
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1473 KiB  
Article
MP-V1 from the Venom of Social Wasp Vespula vulgaris Is a de Novo Type of Mastoparan that Displays Superior Antimicrobial Activities
by Yangseon Kim, Minky Son, Eun-Young Noh, Soonok Kim, Changmu Kim, Joo-Hong Yeo, Chanin Park, Keun Woo Lee and Woo Young Bang
Molecules 2016, 21(4), 512; https://doi.org/10.3390/molecules21040512 - 19 Apr 2016
Cited by 13 | Viewed by 5482
Abstract
Mastoparans from the venom of social wasps have attracted considerable attention as effective antibiotic candidates. In this study, mastoparan V1 (MP-V1) from Vespula vulgaris was first disclosed to have a peptide amino acid sequence distinct from typical mastoparans and its biochemical properties and [...] Read more.
Mastoparans from the venom of social wasps have attracted considerable attention as effective antibiotic candidates. In this study, mastoparan V1 (MP-V1) from Vespula vulgaris was first disclosed to have a peptide amino acid sequence distinct from typical mastoparans and its biochemical properties and antimicrobial effects were compared with those of typical mastoparans MP-L, -X(V) and -B. Circular dichroism (CD) spectroscopy revealed that MP-V1 and -X(V) form more stable α-helical conformations in lipid membrane-like environments than MP-L and -B. In parallel, these two also showed more effective antimicrobial activities against the pathogens than did MP-L and -B. Although MP-V1 had a less stable α-helical conformation than MP-X(V), it showed stronger antimicrobial effects against Streptococcus mutans and Salmonella enterica than MP-X(V). In the meantime, analysis of hemolytic activity revealed a range of doses (~50 μM) that exhibited little potent cytotoxicity on human erythrocytes. Finally, the atypical MP-V1 peptide amino acid sequence provided important clues to understanding its antimicrobial mechanism from a structural perspective. Therefore, it has been concluded that MP-V1 is a de novo type of mastoparan with superior antimicrobial activities against both pathogenic bacteria and fungi, which may be useful in developing multipurpose antimicrobial drugs against infectious diseases. Full article
(This article belongs to the Special Issue Natural Toxins)
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1115 KiB  
Article
Effects of Phenolic Acids on the Growth and Production of T‐2 and HT‐2 Toxins by Fusarium langsethiae and F. sporotrichioides
by Elena Ferruz, Vessela Atanasova‐Pénichon, Marie‐Noëlle Bonnin‐Verdal, Gisèle Marchegay, Laëtitia Pinson‐Gadais, Christine Ducos, Susana Lorán, Agustín Ariño, Christian Barreau and Florence Richard‐Forget
Molecules 2016, 21(4), 449; https://doi.org/10.3390/molecules21040449 - 04 Apr 2016
Cited by 47 | Viewed by 5972
Abstract
The effect of natural phenolic acids was tested on the growth and production of T‐2 and HT‐2 toxins by Fusarium langsethiae and F. sporotrichioides, on Mycotoxin Synthetic medium. Plates treated with 0.5 mM of each phenolic acid (caffeic, chlorogenic, ferulic and p‐coumaric) and [...] Read more.
The effect of natural phenolic acids was tested on the growth and production of T‐2 and HT‐2 toxins by Fusarium langsethiae and F. sporotrichioides, on Mycotoxin Synthetic medium. Plates treated with 0.5 mM of each phenolic acid (caffeic, chlorogenic, ferulic and p‐coumaric) and controls without phenolic acid were incubated for 14 days at 25 °C. Fungal biomass of F. langsethiae and F. sporotrichioides was not reduced by the phenolic acids. However, biosynthesis of T‐2 toxin by F. langsethiae was significantly reduced by chlorogenic (23.1%) and ferulic (26.5%) acids. Production of T‐2 by F. sporotrichioides also decreased with ferulic acid by 23% (p < 0.05). In contrast, p‐coumaric acid significantly stimulated the production of T‐2 and HT‐2 toxins for both strains. A kinetic study of F. langsethiae with 1 mM ferulic acid showed a significant decrease in fungal biomass, whereas T‐2 production increased after 10 days of incubation. The study of gene expression in ferulic supplemented cultures of F. langsethiae revealed a significant inhibition for Tri5, Tri6 and Tri12 genes, while for Tri16 the decrease in gene expression was not statistically significant. Overall, results indicated that phenolic acids had a variable effect on fungal growth and mycotoxin production, depending on the strain and the concentration and type of phenolic acid assayed. Full article
(This article belongs to the Special Issue Natural Toxins)
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651 KiB  
Communication
Potential Health Risks Posed by Plant-Derived Cumulative Neurotoxic Bufadienolides in South Africa
by Christo Botha
Molecules 2016, 21(3), 348; https://doi.org/10.3390/molecules21030348 - 16 Mar 2016
Cited by 12 | Viewed by 8354
Abstract
Bufadienolide-type cardiac glycosides have a worldwide distribution and are mainly synthesized by plants, but there are also animal sources. In South Africa, members of three genera of the Crassulaceae (Cotyledon, Tylecodon and Kalanchoe) cause a unique chronic form of cardiac [...] Read more.
Bufadienolide-type cardiac glycosides have a worldwide distribution and are mainly synthesized by plants, but there are also animal sources. In South Africa, members of three genera of the Crassulaceae (Cotyledon, Tylecodon and Kalanchoe) cause a unique chronic form of cardiac glycoside poisoning, predominantly in small stock. This paretic/paralytic condition is referred to as “krimpsiekte”, cotyledonosis or “nenta”. “Krimpsiekte” is a plant poisoning only reported from South Africa and is regarded as the most important plant poisoning of small stock in the semi-arid Little Karoo and southern fringes of the Great Karoo. The toxicosis is caused by cumulative bufadienolides which have neurotoxic properties. Four types of cumulative neurotoxic bufadienolides, namely cotyledoside, and the tyledosides, orbicusides and lanceotoxins, have been isolated. Based on the structure activity relationships and certain toxicokinetic parameters possible reasons for their accumulation are presented. Consumption of edible tissues from animals that have ingested these plants poses a potential risk to humans. Full article
(This article belongs to the Special Issue Natural Toxins)
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579 KiB  
Article
Antibacterial Activity and Antibiotic-Enhancing Effects of Honeybee Venom against Methicillin-Resistant Staphylococcus aureus
by Sang Mi Han, Joung Min Kim, In Pyo Hong, Soon Ok Woo, Se Gun Kim, He Rye Jang and Sok Cheon Pak
Molecules 2016, 21(1), 79; https://doi.org/10.3390/molecules21010079 - 12 Jan 2016
Cited by 37 | Viewed by 7891
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA), along with other antibiotic resistant bacteria, has become a significant social and clinical problem. There is thus an urgent need to develop naturally bioactive compounds as alternatives to the few antibiotics that remain effective. Here we assessed the in [...] Read more.
Methicillin-resistant Staphylococcus aureus (MRSA), along with other antibiotic resistant bacteria, has become a significant social and clinical problem. There is thus an urgent need to develop naturally bioactive compounds as alternatives to the few antibiotics that remain effective. Here we assessed the in vitro activities of bee venom (BV), alone or in combination with ampicillin, penicillin, gentamicin or vancomycin, on growth of MRSA strains. The antimicrobial activity of BV against MRSA strains was investigated using minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC) and a time-kill assay. Expression of atl which encodes murein hydrolase, a peptidoglycan-degrading enzyme involved in cell separation, was measured by reverse transcription-polymerase chain reaction. The MICs of BV were 0.085 µg/mL and 0.11 µg/mL against MRSA CCARM 3366 and MRSA CCARM 3708, respectively. The MBC of BV against MRSA 3366 was 0.106 µg/mL and that against MRSA 3708 was 0.14 µg/mL. The bactericidal activity of BV corresponded to a decrease of at least 3 log CFU/g cells. The combination of BV with ampicillin or penicillin yielded an inhibitory concentration index ranging from 0.631 to 1.002, indicating a partial and indifferent synergistic effect. Compared to ampicillin or penicillin, both MRSA strains were more susceptible to the combination of BV with gentamicin or vancomycin. The expression of atl gene was increased in MRSA 3366 treated with BV. These results suggest that BV exhibited antibacterial activity and antibiotic-enhancing effects against MRSA strains. The atl gene was increased in MRSA exposed to BV, suggesting that cell division was interrupted. BV warrants further investigation as a natural antimicrobial agent and synergist of antibiotic activity. Full article
(This article belongs to the Special Issue Natural Toxins)
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1704 KiB  
Article
Comparison of Fluorescent Microspheres and Colloidal Gold as Labels in Lateral Flow Immunochromatographic Assays for the Detection of T-2 Toxin
by Xiya Zhang, Chao Wu, Kai Wen, Haiyang Jiang, Jianzhong Shen, Suxia Zhang and Zhanhui Wang
Molecules 2016, 21(1), 27; https://doi.org/10.3390/molecules21010027 - 28 Dec 2015
Cited by 25 | Viewed by 7489
Abstract
A new highly specific and sensitive monoclonal antibody (MAb) to T-2 toxin (T-2) was produced, providing an IC50 value of 1.02 ng/mL and negligible cross-reactivity (CR) to other related mycotoxins. Based on the new MAb, a lateral-flow immunochromatographic assay (LFIA) using colloidal [...] Read more.
A new highly specific and sensitive monoclonal antibody (MAb) to T-2 toxin (T-2) was produced, providing an IC50 value of 1.02 ng/mL and negligible cross-reactivity (CR) to other related mycotoxins. Based on the new MAb, a lateral-flow immunochromatographic assay (LFIA) using colloidal gold (CG) and fluorescent microspheres (FMs) as labels was proposed for T-2. Under the optimized conditions, in rapid qualitative assay, the cut-off values of the CG-LFIA were 400 μg/kg in rice and 50 μg/L in fresh milk, and the cut-off values of the FMs-LFIA were 100 μg/kg in both rice and chicken feed. For the quantitative assay with the FMs-LFIA, the limit of detection (LOD) were 0.23 μg/kg and 0.41 μg/kg in rice and chicken feed, respectively, and the average recoveries ranged from 80.2% to 100.8% with the coefficient of variation (CV) below 10.8%. In addition, we found that the CG-LFIA could tolerate the matrix effect of fresh milk better than the FMs-LFIA, while the FMs-LFIA could tolerate the matrix effect of chicken feed better than CG-LFIA under the same experimental conditions. These results provide a certain reference for the selection of appropriate labels to establish a rapid LFIA in various biological samples. Full article
(This article belongs to the Special Issue Natural Toxins)
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Review

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1547 KiB  
Review
Emerging Roles of Toxin-Antitoxin Modules in Bacterial Pathogenesis
by Barbara Kędzierska and Finbarr Hayes
Molecules 2016, 21(6), 790; https://doi.org/10.3390/molecules21060790 - 17 Jun 2016
Cited by 96 | Viewed by 10790
Abstract
Toxin-antitoxin (TA) cassettes are encoded widely by bacteria. The modules typically comprise a protein toxin and protein or RNA antitoxin that sequesters the toxin factor. Toxin activation in response to environmental cues or other stresses promotes a dampening of metabolism, most notably protein [...] Read more.
Toxin-antitoxin (TA) cassettes are encoded widely by bacteria. The modules typically comprise a protein toxin and protein or RNA antitoxin that sequesters the toxin factor. Toxin activation in response to environmental cues or other stresses promotes a dampening of metabolism, most notably protein translation, which permits survival until conditions improve. Emerging evidence also implicates TAs in bacterial pathogenicity. Bacterial persistence involves entry into a transient semi-dormant state in which cells survive unfavorable conditions including killing by antibiotics, which is a significant clinical problem. TA complexes play a fundamental role in inducing persistence by downregulating cellular metabolism. Bacterial biofilms are important in numerous chronic inflammatory and infectious diseases and cause serious therapeutic problems due to their multidrug tolerance and resistance to host immune system actions. Multiple TAs influence biofilm formation through a network of interactions with other factors that mediate biofilm production and maintenance. Moreover, in view of their emerging contributions to bacterial virulence, TAs are potential targets for novel prophylactic and therapeutic approaches that are required urgently in an era of expanding antibiotic resistance. This review summarizes the emerging evidence that implicates TAs in the virulence profiles of a diverse range of key bacterial pathogens that trigger serious human disease. Full article
(This article belongs to the Special Issue Natural Toxins)
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633 KiB  
Review
Fusarium Toxins in Cereals: Occurrence, Legislation, Factors Promoting the Appearance and Their Management
by Davide Ferrigo, Alessandro Raiola and Roberto Causin
Molecules 2016, 21(5), 627; https://doi.org/10.3390/molecules21050627 - 13 May 2016
Cited by 231 | Viewed by 13733
Abstract
Fusarium diseases of small grain cereals and maize cause significant yield losses worldwide. Fusarium infections result in reduced grain yield and contamination with mycotoxins, some of which have a notable impact on human and animal health. Regulations on maximum limits have been established [...] Read more.
Fusarium diseases of small grain cereals and maize cause significant yield losses worldwide. Fusarium infections result in reduced grain yield and contamination with mycotoxins, some of which have a notable impact on human and animal health. Regulations on maximum limits have been established in various countries to protect consumers from the harmful effects of these mycotoxins. Several factors are involved in Fusarium disease and mycotoxin occurrence and among them environmental factors and the agronomic practices have been shown to deeply affect mycotoxin contamination in the field. In the present review particular emphasis will be placed on how environmental conditions and stress factors for the crops can affect Fusarium infection and mycotoxin production, with the aim to provide useful knowledge to develop strategies to prevent mycotoxin accumulation in cereals. Full article
(This article belongs to the Special Issue Natural Toxins)
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511 KiB  
Review
Anti-Inflammatory Applications of Melittin, a Major Component of Bee Venom: Detailed Mechanism of Action and Adverse Effects
by Gihyun Lee and Hyunsu Bae
Molecules 2016, 21(5), 616; https://doi.org/10.3390/molecules21050616 - 11 May 2016
Cited by 146 | Viewed by 19994
Abstract
Inflammation is a pervasive phenomenon triggered by the innate and adaptive immune systems to maintain homeostasis. The phenomenon normally leads to recovery from infection and healing, but when not properly phased, inflammation may cause immune disorders. Bee venom is a toxin that bees [...] Read more.
Inflammation is a pervasive phenomenon triggered by the innate and adaptive immune systems to maintain homeostasis. The phenomenon normally leads to recovery from infection and healing, but when not properly phased, inflammation may cause immune disorders. Bee venom is a toxin that bees use for their protection from enemies. However, for centuries it has been used in the Orient as an anti-inflammatory medicine for the treatment of chronic inflammatory diseases. Bee venom and its major component, melittin, are potential means of reducing excessive immune responses and provide new alternatives for the control of inflammatory diseases. Recent experimental studies show that the biological functions of melittin could be applied for therapeutic use in vitro and in vivo. Reports verifying the therapeutic effects of melittin are accumulating in the literature, but the cellular mechanism(s) of the anti-inflammatory effects of melittin are not fully elucidated. In the present study, we review the current knowledge on the therapeutic effects of melittin and its detailed mechanisms of action against several inflammatory diseases including skin inflammation, neuroinflammation, atherosclerosis, arthritis and liver inflammation, its adverse effects as well as future prospects regarding the use of melittin. Full article
(This article belongs to the Special Issue Natural Toxins)
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1478 KiB  
Review
Military Importance of Natural Toxins and Their Analogs
by Vladimír Pitschmann and Zdeněk Hon
Molecules 2016, 21(5), 556; https://doi.org/10.3390/molecules21050556 - 28 Apr 2016
Cited by 32 | Viewed by 10185
Abstract
Toxin weapon research, development, production and the ban on its uses is an integral part of international law, with particular attention paid to the protection against these weapons. In spite of this, hazards associated with toxins cannot be completely excluded. Some of these [...] Read more.
Toxin weapon research, development, production and the ban on its uses is an integral part of international law, with particular attention paid to the protection against these weapons. In spite of this, hazards associated with toxins cannot be completely excluded. Some of these hazards are also pointed out in the present review. The article deals with the characteristics and properties of natural toxins and synthetic analogs potentially constituting the basis of toxin weapons. It briefly describes the history of military research and the use of toxins from distant history up to the present age. With respect to effective disarmament conventions, it mentions certain contemporary concepts of possible toxin applications for military purposes and the protection of public order (suppression of riots); it also briefly refers to the question of terrorism. In addition, it deals with certain traditional as well as modern technologies of the research, synthesis, and use of toxins, which can affect the continuing development of toxin weapons. These are, for example, cases of new toxins from natural sources, their chemical synthesis, production of synthetic analogs, the possibility of using methods of genetic engineering and modern biotechnologies or the possible applications of nanotechnology and certain pharmaceutical methods for the effective transfer of toxins into the organism. The authors evaluate the military importance of toxins based on their comparison with traditional chemical warfare agents. They appeal to the ethics of the scientific work as a principal condition for the prevention of toxin abuse in wars, military conflicts, as well as in non-military attacks. Full article
(This article belongs to the Special Issue Natural Toxins)
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1164 KiB  
Review
The Effect of Low Monotonic Doses of Zearalenone on Selected Reproductive Tissues in Pre-Pubertal Female Dogs—A Review
by Magdalena Gajęcka, Łukasz Zielonka and Maciej Gajęcki
Molecules 2015, 20(11), 20669-20687; https://doi.org/10.3390/molecules201119726 - 19 Nov 2015
Cited by 24 | Viewed by 6554
Abstract
The growing interest in toxic substances combined with advancements in biological sciences has shed a new light on the problem of mycotoxins contaminating feeds and foods. An interdisciplinary approach was developed by identifying dose-response relationships in key research concepts, including the low dose [...] Read more.
The growing interest in toxic substances combined with advancements in biological sciences has shed a new light on the problem of mycotoxins contaminating feeds and foods. An interdisciplinary approach was developed by identifying dose-response relationships in key research concepts, including the low dose theory of estrogen-like compounds, hormesis, NOAEL dose, compensatory response and/or food tolerance, and effects of exposure to undesirable substances. The above considerations increased the researchers’ interest in risk evaluation, namely: (i) clinical symptoms associated with long-term, daily exposure to low doses of a toxic compound; and (ii) dysfunctions at cellular or tissue level that do not produce clinical symptoms. Research advancements facilitate the extrapolation of results and promote the use of novel tools for evaluating the risk of exposure, for example exposure to zearalenone in pre-pubertal female dogs. The arguments presented in this paper suggest that low doses of zearalenone in commercial feeds stimulate metabolic processes and increase weight gains. Those processes are accompanied by lower proliferation rates in the ovaries, neoangiogenesis and vasodilation in the ovaries and the uterus, changes in the steroid hormone profile, and changes in the activity of hydroxysteroid dehydrogenases. All of the above changes result from exogenous hyperestrogenizm. Full article
(This article belongs to the Special Issue Natural Toxins)
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