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Toxins, Volume 8, Issue 3 (March 2016)

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Cover Story (view full-size image) The threat of antibiotic resistance in bacterial pathogens has prompted calls for alternative [...] Read more.
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Open AccessArticle Gastrointestinal Degradation of Fumonisin B1 by Carboxylesterase FumD Prevents Fumonisin Induced Alteration of Sphingolipid Metabolism in Turkey and Swine
Received: 1 February 2016 / Revised: 3 March 2016 / Accepted: 14 March 2016 / Published: 21 March 2016
Cited by 13 | Viewed by 2254 | PDF Full-text (1432 KB) | HTML Full-text | XML Full-text
Abstract
The mycotoxin fumonisin B1 (FB1) is a frequent contaminant of feed and causes various adverse health effects in domestic animals. Hence, effective strategies are needed to prevent the impact of fumonisins on livestock productivity. Here we evaluated the capability of [...] Read more.
The mycotoxin fumonisin B1 (FB1) is a frequent contaminant of feed and causes various adverse health effects in domestic animals. Hence, effective strategies are needed to prevent the impact of fumonisins on livestock productivity. Here we evaluated the capability of the fumonisin carboxylesterase FumD to degrade FB1 to its less toxic metabolite hydrolyzed FB1 (HFB1) in the gastrointestinal tract of turkeys and pigs. First, an ex vivo pig model was used to examine the activity of FumD under digestive conditions. Within 2 h of incubation with FumD, FB1 was completely degraded to HFB1 in the duodenum and jejunum, respectively. To test the efficacy of the commercial application of FumD (FUMzyme) in vivo, female turkeys (n = 5) received either basal feed (CON), fumonisin-contaminated feed (15 mg/kg FB1+FB2; FB) or fumonisin-contaminated feed supplemented with FUMzyme (15 U/kg; FB+FUMzyme) for 14 days ad libitum. Addition of FUMzyme resulted in significantly decreased levels of FB1 in excreta, whereas HFB1 concentrations were significantly increased. Compared to the FB group (0.24 ± 0.02), the mean serum sphinganine-to-sphingosine (Sa/So) ratio was significantly reduced in the FB+FUMzyme group (0.19 ± 0.02), thus resembling values of the CON group (0.16 ± 0.02). Similarly, exposure of piglets (n = 10) to 2 mg/kg FB1+FB2 for 42 days caused significantly elevated serum Sa/So ratios (0.39 ± 0.15) compared to the CON group (0.14 ± 0.01). Supplementation with FUMzyme (60 U/kg) resulted in gastrointestinal degradation of FB1 and unaffected Sa/So ratios (0.16 ± 0.02). Thus, the carboxylesterase FumD represents an effective strategy to detoxify FB1 in the digestive tract of turkeys and pigs. Full article
(This article belongs to the collection Fusarium Toxins – Relevance for Human and Animal Health)
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Open AccessReview Ochratoxin A Producing Fungi, Biosynthetic Pathway and Regulatory Mechanisms
Received: 1 February 2016 / Revised: 28 February 2016 / Accepted: 14 March 2016 / Published: 21 March 2016
Cited by 25 | Viewed by 2268 | PDF Full-text (272 KB) | HTML Full-text | XML Full-text
Abstract
Ochratoxin A (OTA), mainly produced by Aspergillus and Penicillum species, is one of the most important mycotoxin contaminants in agricultural products. It is detrimental to human health because of its nephrotoxicity, hepatotoxicity, carcinogenicity, teratogenicity, and immunosuppression. OTA structurally consists of adihydrocoumarin moiety linked [...] Read more.
Ochratoxin A (OTA), mainly produced by Aspergillus and Penicillum species, is one of the most important mycotoxin contaminants in agricultural products. It is detrimental to human health because of its nephrotoxicity, hepatotoxicity, carcinogenicity, teratogenicity, and immunosuppression. OTA structurally consists of adihydrocoumarin moiety linked with l-phenylalanine via an amide bond. OTA biosynthesis has been putatively hypothesized, although several contradictions exist on some processes of the biosynthetic pathway. We discuss recent information on molecular studies of OTA biosynthesis despite insufficient genetic background in detail. Accordingly, genetic regulation has also been explored with regard to the interaction between the regulators and the environmental factors. In this review, we focus on three aspects of OTA: OTA-producing strains, OTA biosynthetic pathway and the regulation mechanisms of OTA production. This can pave the way to assist in protecting food and feed from OTA contamination by understanding OTA biosynthetic pathway and regulatory mechanisms. Full article
(This article belongs to the collection Ochratoxins-Collection)
Open AccessArticle Efficacy and Safety of Intravesical OnabotulinumtoxinA Injection in Patients with Detrusor Hyperactivity and Impaired Contractility
Received: 15 February 2016 / Revised: 7 March 2016 / Accepted: 11 March 2016 / Published: 18 March 2016
Cited by 5 | Viewed by 1569 | PDF Full-text (597 KB) | HTML Full-text | XML Full-text
Abstract
We investigated the efficacy and safety of intravesical onabotulinumtoxinA injection in patients with detrusor hyperactivity and impaired contractility (DHIC). Twenty-one patients with urodynamically proven DHIC and 21 age-matched patients with overactive bladder (OAB) with urodynamic detrusor overactivity were treated with intravesical injections of [...] Read more.
We investigated the efficacy and safety of intravesical onabotulinumtoxinA injection in patients with detrusor hyperactivity and impaired contractility (DHIC). Twenty-one patients with urodynamically proven DHIC and 21 age-matched patients with overactive bladder (OAB) with urodynamic detrusor overactivity were treated with intravesical injections of 100 U of onabotulinumtoxinA. The overactive bladder symptom score, urgency severity score, patient perception of bladder condition, global response assessment, voiding diary, and procedure-related adverse events (AE) at baseline, two weeks, one, three, and six months after treatment were assessed. The results showed that the subjective symptom scores improved significantly in both groups, and the scores did not differ between the groups. The decrease in urgency episodes and urgency urinary incontinence were noted in OAB patients but not in DHIC patients. Although the incidence of AEs was comparable between the groups, the therapeutic efficacy lasted for a mean of 4.9 ± 4.8 months in DHIC patients and 7.2 ± 3.3 months in OAB patients (p = 0.03). We concluded that the efficacy of intravesical onabotulinumtoxinA injection for DHIC patients was limited and short-term. Nevertheless, AEs did not increase in DHIC. Intravesical onabotulinumtoxinA might not be a good indication in patients with DHIC and high post-voiding residual urine. Physicians should inform patients of the potential benefits and risks of onabotulinumtoxinA injection for treatment of DHIC. Full article
(This article belongs to the Special Issue Botulinum Toxin A on Lower Urinary Tract Dysfunction)
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Open AccessFeature PaperReview Potential Effect of Liposomes and Liposome-Encapsulated Botulinum Toxin and Tacrolimus in the Treatment of Bladder Dysfunction
Received: 3 February 2016 / Revised: 26 February 2016 / Accepted: 29 February 2016 / Published: 18 March 2016
Cited by 3 | Viewed by 1804 | PDF Full-text (2288 KB) | HTML Full-text | XML Full-text
Abstract
Bladder drug delivery via catheter instillation is a widely used treatment for recurrence of superficial bladder cancer. Intravesical instillation of liposomal botulinum toxin has recently shown promise in the treatment of overactive bladder and interstitial cystitis/bladder pain syndrome, and studies of liposomal tacrolimus [...] Read more.
Bladder drug delivery via catheter instillation is a widely used treatment for recurrence of superficial bladder cancer. Intravesical instillation of liposomal botulinum toxin has recently shown promise in the treatment of overactive bladder and interstitial cystitis/bladder pain syndrome, and studies of liposomal tacrolimus instillations show promise in the treatment of hemorrhagic cystitis. Liposomes are lipid vesicles composed of phospholipid bilayers surrounding an aqueous core that can encapsulate hydrophilic and hydrophobic drug molecules to be delivered to cells via endocytosis. This review will present new developments on instillations of liposomes and liposome-encapsulated drugs into the urinary bladder for treating lower urinary tract dysfunction. Full article
(This article belongs to the Special Issue Botulinum Toxin A on Lower Urinary Tract Dysfunction)
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Open AccessReview Herbal Medicines Induced Anticholinergic Poisoning in Hong Kong
Received: 4 February 2016 / Revised: 9 March 2016 / Accepted: 11 March 2016 / Published: 18 March 2016
Cited by 6 | Viewed by 1760 | PDF Full-text (209 KB) | HTML Full-text | XML Full-text
Abstract
In the present review, the main objective was to report the incidence and causes of herbal medicines induced anticholinergic poisoning in Hong Kong during 1989–2012 and to emphasize the importance of pharmacovigilance, investigations and preventive measures. Relevant papers, official figures and unpublished data [...] Read more.
In the present review, the main objective was to report the incidence and causes of herbal medicines induced anticholinergic poisoning in Hong Kong during 1989–2012 and to emphasize the importance of pharmacovigilance, investigations and preventive measures. Relevant papers, official figures and unpublished data were obtained from Medline search, the Department of Health and the Drug and Poisons Information Bureau. In the New Territories East (where ~20% of the Hong Kong population lived), the incidence of herbal medicines induced anticholinergic poisoning during 1989–1993 was 0.09 per 100,000 population. There were no confirmed cases during 1994–1996. In the whole of Hong Kong, the incidence during 2000–June 2005 was 0.03 per 100,000 population. Contamination of Rhizoma Atractylodis (50%) and erroneous substitution (42%) were the main causes. The incidence during 2008–2012 was 0.06 per 100,000 population. Contamination of non-toxic herbs (50%) and erroneous substitution (41%) were the main causes. In Hong Kong, contamination of non-toxic herbs by tropane alkaloids and substitution of Flos Campsis by toxic Flos Daturae Metelis were the predominant causes of herbal medicines induced anticholinergic poisoning. Systematic studies along the supply chain are necessary to identify the likely sources of contamination. If erroneous substitution of Flos Campsis by Flos Daturae Metelis could be prevented, 40% of herbal medicines induced anticholinergic poisoning would not have occurred. Regular inspection of the retailer, continuing education for the staff in the herbal trade and repeated publicity measures will also be required. Pharmacovigilance of herbal medicines should help determine the incidence and causes of adverse reactions and monitor the effectiveness of preventive measures. Full article
(This article belongs to the collection Toxicity of Natural Alkaloids)
Open AccessArticle Validation of the Target Protein of Insecticidal Dihydroagarofuran Sesquiterpene Polyesters
Received: 5 February 2016 / Revised: 8 March 2016 / Accepted: 14 March 2016 / Published: 18 March 2016
Cited by 4 | Viewed by 1515 | PDF Full-text (2346 KB) | HTML Full-text | XML Full-text
Abstract
A series of insecticidal dihydroagarofuran sesquiterpene polyesters were isolated from the root bark of Chinese bittersweet (Celastrus angulatus Max). A previous study indicated that these compounds affect the digestive system of insects, and aminopeptidase N3 and V-ATPase have been identified as the [...] Read more.
A series of insecticidal dihydroagarofuran sesquiterpene polyesters were isolated from the root bark of Chinese bittersweet (Celastrus angulatus Max). A previous study indicated that these compounds affect the digestive system of insects, and aminopeptidase N3 and V-ATPase have been identified as the most putative target proteins by affinity chromatography. In this study, the correlation between the affinity of the compounds to subunit H and the insecticidal activity or inhibitory effect on the activity of V-ATPase was analyzed to validate the target protein. Results indicated that the subunit H of V-ATPase was the target protein of the insecticidal compounds. In addition, the possible mechanism of action of the compounds was discussed. The results provide new ideas for developing pesticides acting on V-ATPase of insects. Full article
(This article belongs to the Section Plant Toxins)
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Open AccessArticle Analgesic Effects of GpTx-1, PF-04856264 and CNV1014802 in a Mouse Model of NaV1.7-Mediated Pain
Received: 25 January 2016 / Revised: 8 March 2016 / Accepted: 10 March 2016 / Published: 17 March 2016
Cited by 30 | Viewed by 4173 | PDF Full-text (3214 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Loss-of-function mutations of NaV1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of NaV1.7 a promising therapeutic strategy for the treatment [...] Read more.
Loss-of-function mutations of NaV1.7 lead to congenital insensitivity to pain, a rare condition resulting in individuals who are otherwise normal except for the inability to sense pain, making pharmacological inhibition of NaV1.7 a promising therapeutic strategy for the treatment of pain. We characterized a novel mouse model of NaV1.7-mediated pain based on intraplantar injection of the scorpion toxin OD1, which is suitable for rapid in vivo profiling of NaV1.7 inhibitors. Intraplantar injection of OD1 caused spontaneous pain behaviors, which were reversed by co-injection with NaV1.7 inhibitors and significantly reduced in NaV1.7−/− mice. To validate the use of the model for profiling NaV1.7 inhibitors, we determined the NaV selectivity and tested the efficacy of the reported NaV1.7 inhibitors GpTx-1, PF-04856264 and CNV1014802 (raxatrigine). GpTx-1 selectively inhibited NaV1.7 and was effective when co-administered with OD1, but lacked efficacy when delivered systemically. PF-04856264 state-dependently and selectively inhibited NaV1.7 and significantly reduced OD1-induced spontaneous pain when delivered locally and systemically. CNV1014802 state-dependently, but non-selectively, inhibited NaV channels and was only effective in the OD1 model when delivered systemically. Our novel model of NaV1.7-mediated pain based on intraplantar injection of OD1 is thus suitable for the rapid in vivo characterization of the analgesic efficacy of NaV1.7 inhibitors. Full article
(This article belongs to the Special Issue Animal Toxins and Biological Ion Channels)
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Open AccessFeature PaperReview Shiga Toxins as Multi-Functional Proteins: Induction of Host Cellular Stress Responses, Role in Pathogenesis and Therapeutic Applications
Received: 22 October 2015 / Revised: 25 February 2016 / Accepted: 29 February 2016 / Published: 17 March 2016
Cited by 25 | Viewed by 3008 | PDF Full-text (1448 KB) | HTML Full-text | XML Full-text
Abstract
Shiga toxins (Stxs) produced by Shiga toxin-producing bacteria Shigella dysenteriae serotype 1 and select serotypes of Escherichia coli are primary virulence factors in the pathogenesis of hemorrhagic colitis progressing to potentially fatal systemic complications, such as hemolytic uremic syndrome and central nervous system [...] Read more.
Shiga toxins (Stxs) produced by Shiga toxin-producing bacteria Shigella dysenteriae serotype 1 and select serotypes of Escherichia coli are primary virulence factors in the pathogenesis of hemorrhagic colitis progressing to potentially fatal systemic complications, such as hemolytic uremic syndrome and central nervous system abnormalities. Current therapeutic options to treat patients infected with toxin-producing bacteria are limited. The structures of Stxs, toxin-receptor binding, intracellular transport and the mode of action of the toxins have been well defined. However, in the last decade, numerous studies have demonstrated that in addition to being potent protein synthesis inhibitors, Stxs are also multifunctional proteins capable of activating multiple cell stress signaling pathways, which may result in apoptosis, autophagy or activation of the innate immune response. Here, we briefly present the current understanding of Stx-activated signaling pathways and provide a concise review of therapeutic applications to target tumors by engineering the toxins. Full article
(This article belongs to the collection Shiga Toxins)
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Open AccessArticle Characterization of Enzymatic Activity of MlrB and MlrC Proteins Involved in Bacterial Degradation of Cyanotoxins Microcystins
Received: 12 January 2016 / Revised: 29 February 2016 / Accepted: 7 March 2016 / Published: 16 March 2016
Cited by 10 | Viewed by 2466 | PDF Full-text (1940 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Bacterial degradation of toxic microcystins produced by cyanobacteria is a common phenomenon. However, our understanding of the mechanisms of these processes is rudimentary. In this paper several novel discoveries regarding the action of the enzymes of the mlr cluster responsible for microcystin biodegradation [...] Read more.
Bacterial degradation of toxic microcystins produced by cyanobacteria is a common phenomenon. However, our understanding of the mechanisms of these processes is rudimentary. In this paper several novel discoveries regarding the action of the enzymes of the mlr cluster responsible for microcystin biodegradation are presented using recombinant proteins. In particular, the predicted active sites of the recombinant MlrB and MlrC were analyzed using functional enzymes and their inactive muteins. A new degradation intermediate, a hexapeptide derived from linearized microcystins by MlrC, was discovered. Furthermore, the involvement of MlrA and MlrB in further degradation of the hexapeptides was confirmed and a corrected biochemical pathway of microcystin biodegradation has been proposed. Full article
(This article belongs to the collection Marine and Freshwater Toxins)
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Open AccessArticle Adverse Events of Intravesical OnabotulinumtoxinA Injection between Patients with Overactive Bladder and Interstitial Cystitis—Different Mechanisms of Action of Botox on Bladder Dysfunction?
Received: 17 January 2016 / Revised: 29 February 2016 / Accepted: 7 March 2016 / Published: 16 March 2016
Cited by 4 | Viewed by 1847 | PDF Full-text (959 KB) | HTML Full-text | XML Full-text
Abstract
Intravesical onabotulinumtoxinA (BoNT-A) injections have been proposed to treat both overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS) in patients with refractory conditions. We compared adverse events (AEs) after BoNT-A treatment between IC/BPS and OAB in women. IC/BPS patients who failed conventional [...] Read more.
Intravesical onabotulinumtoxinA (BoNT-A) injections have been proposed to treat both overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS) in patients with refractory conditions. We compared adverse events (AEs) after BoNT-A treatment between IC/BPS and OAB in women. IC/BPS patients who failed conventional treatments were enrolled to receive suburothelial injections of BoNT-A (100 U) followed by hydrodistention. Age matched OAB female patients refractory to antimuscarinic agents underwent BoNT-A (100 U) injections. The bladder capacity, maximum flow rate (Qmax), post-void residual (PVR), and voiding efficiency (VE) at baseline, 3 and 6 months, and the post-treatment AEs were analyzed between groups. Finally, 89 IC/BPS and 72 OAB women were included. In the OAB group, the bladder capacity and PVR increased, and VE decreased significantly at three and six months after BoNT-A treatment. In the IC/BPS group, the Qmax increased significantly at six months. There were significant differences in changes of capacity, Qmax, PVR and VE between the two groups. Moreover, OAB patients suffered more frequently from events of hematuria, UTI, and large PVR (>200 mL), but less frequently from events of straining to void. In conclusion, OAB women had higher PVR volume and lower VE than those in IC/BPS after BoNT-A injections. These results imply that the bladder contractility of OAB patients are more susceptible to BoNT-A, which might reflect the different mechanisms of action of Botox on bladder dysfunction. Further investigations to confirm this hypothesis are warranted. Full article
(This article belongs to the Special Issue Botulinum Toxin A on Lower Urinary Tract Dysfunction)
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Open AccessFeature PaperArticle Maternal Ingestion of Ipomoea carnea: Effects on Goat-Kid Bonding and Behavior
Received: 9 February 2016 / Revised: 7 March 2016 / Accepted: 9 March 2016 / Published: 16 March 2016
Cited by 3 | Viewed by 1818 | PDF Full-text (1260 KB) | HTML Full-text | XML Full-text
Abstract
Ipomoea carnea is a toxic plant found in Brazil and other tropical and subtropical countries and often causes poisoning of livestock. The plant contains the alkaloids swainsonine and calystegines, which inhibit key cellular enzymes and cause systematic cell death. This study evaluated the [...] Read more.
Ipomoea carnea is a toxic plant found in Brazil and other tropical and subtropical countries and often causes poisoning of livestock. The plant contains the alkaloids swainsonine and calystegines, which inhibit key cellular enzymes and cause systematic cell death. This study evaluated the behavioral effects of prenatal ingestion of this plant on dams and their kids. Twenty-four pregnant goats were randomly allocated into four treatment groups and received the following doses (g/kg BW) of fresh I. carnea: 0 (control group), 1.0 (IC1), 3.0 (IC3), and 5.0 (IC5) from day 27 of gestation until parturition. Dam and kid bonding and behavior were evaluated by several tests, immediately after birth until six weeks of age. Dams from IC3 and IC5 groups spent less time paying attention to the newborn. There was a lack of maternal-infant bonding due to I. carnea intoxication. Kids from treated dams had difficulty in standing, suckling, and in recognizing their mother hours after birth. I. carnea can also compromise the kids’ ability to learn and to retain spatial memory. We suggest that kids from pregnant goats given I. carnea during gestation have significant behavioral alterations and developmental delays that may compromise their survival. Full article
(This article belongs to the collection Toxicity of Natural Alkaloids)
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Open AccessFeature PaperReview Clostridium perfringens Enterotoxin: Action, Genetics, and Translational Applications
Received: 23 February 2016 / Revised: 4 March 2016 / Accepted: 8 March 2016 / Published: 16 March 2016
Cited by 37 | Viewed by 4962 | PDF Full-text (2264 KB) | HTML Full-text | XML Full-text
Abstract
Clostridium perfringens enterotoxin (CPE) is responsible for causing the gastrointestinal symptoms of several C. perfringens food- and nonfood-borne human gastrointestinal diseases. The enterotoxin gene (cpe) is located on either the chromosome (for most C. perfringens type A food poisoning strains) or [...] Read more.
Clostridium perfringens enterotoxin (CPE) is responsible for causing the gastrointestinal symptoms of several C. perfringens food- and nonfood-borne human gastrointestinal diseases. The enterotoxin gene (cpe) is located on either the chromosome (for most C. perfringens type A food poisoning strains) or large conjugative plasmids (for the remaining type A food poisoning and most, if not all, other CPE-producing strains). In all CPE-positive strains, the cpe gene is strongly associated with insertion sequences that may help to assist its mobilization and spread. During disease, CPE is produced when C. perfringens sporulates in the intestines, a process involving several sporulation-specific alternative sigma factors. The action of CPE starts with its binding to claudin receptors to form a small complex; those small complexes then oligomerize to create a hexameric prepore on the membrane surface. Beta hairpin loops from the CPE molecules in the prepore assemble into a beta barrel that inserts into the membrane to form an active pore that enhances calcium influx, causing cell death. This cell death results in intestinal damage that causes fluid and electrolyte loss. CPE is now being explored for translational applications including cancer therapy/diagnosis, drug delivery, and vaccination. Full article
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Open AccessReview Targeting Staphylococcus aureus Toxins: A Potential form of Anti-Virulence Therapy
Received: 18 February 2016 / Revised: 3 March 2016 / Accepted: 10 March 2016 / Published: 15 March 2016
Cited by 42 | Viewed by 4288 | PDF Full-text (2130 KB) | HTML Full-text | XML Full-text
Abstract
Staphylococcus aureus is an opportunistic pathogen and the leading cause of a wide range of severe clinical infections. The range of diseases reflects the diversity of virulence factors produced by this pathogen. To establish an infection in the host, S. aureus expresses an [...] Read more.
Staphylococcus aureus is an opportunistic pathogen and the leading cause of a wide range of severe clinical infections. The range of diseases reflects the diversity of virulence factors produced by this pathogen. To establish an infection in the host, S. aureus expresses an inclusive set of virulence factors such as toxins, enzymes, adhesins, and other surface proteins that allow the pathogen to survive under extreme conditions and are essential for the bacteria’s ability to spread through tissues. Expression and secretion of this array of toxins and enzymes are tightly controlled by a number of regulatory systems. S. aureus is also notorious for its ability to resist the arsenal of currently available antibiotics and dissemination of various multidrug-resistant S. aureus clones limits therapeutic options for a S. aureus infection. Recently, the development of anti-virulence therapeutics that neutralize S. aureus toxins or block the pathways that regulate toxin production has shown potential in thwarting the bacteria’s acquisition of antibiotic resistance. In this review, we provide insights into the regulation of S. aureus toxin production and potential anti-virulence strategies that target S. aureus toxins. Full article
(This article belongs to the collection Staphylococcus aureus Toxins)
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Open AccessArticle Mast Cell Targeted Chimeric Toxin Can Be Developed as an Adjunctive Therapy in Colon Cancer Treatment
Received: 5 January 2016 / Revised: 22 February 2016 / Accepted: 23 February 2016 / Published: 11 March 2016
Cited by 4 | Viewed by 2015 | PDF Full-text (2747 KB) | HTML Full-text | XML Full-text
Abstract
The association of colitis with colorectal cancer has become increasingly clear with mast cells being identified as important inflammatory cells in the process. In view of the relationship between mast cells and cancer, we studied the effect and mechanisms of mast cells in [...] Read more.
The association of colitis with colorectal cancer has become increasingly clear with mast cells being identified as important inflammatory cells in the process. In view of the relationship between mast cells and cancer, we studied the effect and mechanisms of mast cells in the development of colon cancer. Functional and mechanistic insights were gained from ex vivo and in vivo studies of cell interactions between mast cells and CT26 cells. Further evidence was reversely obtained in studies of mast cell targeted Fcε-PE40 chimeric toxin. Experiments revealed mast cells could induce colon tumor cell proliferation and invasion. Cancer progression was found to be related to the density of mast cells in colonic submucosa. The activation of MAPK, Rho-GTPase, and STAT pathways in colon cancer cells was triggered by mast cells during cell-to-cell interaction. Lastly, using an Fcε-PE40 chimeric toxin we constructed, we confirmed the promoting effect of mast cells in development of colon cancer. Mast cells are a promoting factor of colon cancer and thus also a potential therapeutic target. The Fcε-PE40 chimeric toxin targeting mast cells could effectively prevent colon cancer in vitro and in vivo. Consequently, these data may demonstrate a novel immunotherapeutic approach for the treatment of tumors. Full article
(This article belongs to the Section Bacterial Toxins)
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Open AccessArticle PhTx3-4, a Spider Toxin Calcium Channel Blocker, Reduces NMDA-Induced Injury of the Retina
Received: 1 November 2015 / Revised: 26 January 2016 / Accepted: 1 March 2016 / Published: 11 March 2016
Cited by 7 | Viewed by 2815 | PDF Full-text (2262 KB) | HTML Full-text | XML Full-text
Abstract
The in vivo neuroprotective effect of PhTx3-4, a spider toxin N-P/Q calcium channel blocker, was studied in a rat model of NMDA-induced injury of the retina. NMDA (N-Methyl-d-Aspartate)-induced retinal injury in rats reduced the b-wave amplitude by 62% ± [...] Read more.
The in vivo neuroprotective effect of PhTx3-4, a spider toxin N-P/Q calcium channel blocker, was studied in a rat model of NMDA-induced injury of the retina. NMDA (N-Methyl-d-Aspartate)-induced retinal injury in rats reduced the b-wave amplitude by 62% ± 3.6%, indicating the severity of the insult. PhTx3-4 treatment increased the amplitude of the b-wave, which was almost equivalent to the control retinas that were not submitted to injury. The PhTx3-4 functional protection of the retinas recorded on the ERG also was observed in the neuroprotection of retinal cells. NMDA-induced injury reduced live cells in the retina layers and the highest reduction, 84%, was in the ganglion cell layer. Notably, PhTx3-4 treatment caused a remarkable reduction of dead cells in the retina layers, and the highest neuroprotective effect was in the ganglion cells layer. NMDA-induced cytotoxicity of the retina increased the release of glutamate, reactive oxygen species (ROS) production and oxidative stress. PhTx3-4 treatment reduced glutamate release, ROS production and oxidative stress measured by malondialdehyde. Thus, we presented for the first time evidence of in vivo neuroprotection from NMDA-induced retinal injury by PhTx3-4 (-ctenitoxin-Pn3a), a spider toxin that blocks N-P/Q calcium channels. Full article
(This article belongs to the Special Issue Arthropod Venoms)
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Open AccessFeature PaperReview The Ins and Outs of Anthrax Toxin
Received: 18 January 2016 / Revised: 28 February 2016 / Accepted: 1 March 2016 / Published: 10 March 2016
Cited by 18 | Viewed by 3168 | PDF Full-text (1646 KB) | HTML Full-text | XML Full-text
Abstract
Anthrax is a severe, although rather rare, infectious disease that is caused by the Gram-positive, spore-forming bacterium Bacillus anthracis. The infectious form is the spore and the major virulence factors of the bacterium are its poly-γ-D-glutamic acid capsule and the tripartite anthrax [...] Read more.
Anthrax is a severe, although rather rare, infectious disease that is caused by the Gram-positive, spore-forming bacterium Bacillus anthracis. The infectious form is the spore and the major virulence factors of the bacterium are its poly-γ-D-glutamic acid capsule and the tripartite anthrax toxin. The discovery of the anthrax toxin receptors in the early 2000s has allowed in-depth studies on the mechanisms of anthrax toxin cellular entry and translocation from the endocytic compartment to the cytoplasm. The toxin generally hijacks the endocytic pathway of CMG2 and TEM8, the two anthrax toxin receptors, in order to reach the endosomes. From there, the pore-forming subunit of the toxin inserts into endosomal membranes and enables translocation of the two catalytic subunits. Insertion of the pore-forming unit preferentially occurs in intraluminal vesicles rather than the limiting membrane of the endosome, leading to the translocation of the enzymatic subunits in the lumen of these vesicles. This has important consequences that will be discussed. Ultimately, the toxins reach the cytosol where they act on their respective targets. Target modification has severe consequences on cell behavior, in particular on cells of the immune system, allowing the spread of the bacterium, in severe cases leading to host death. Here we will review the literature on anthrax disease with a focus on the structure of the toxin, how it enters cells and its immunological effects. Full article
(This article belongs to the collection Anthrax Toxins)
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Open AccessArticle Heart Alterations after Domoic Acid Administration in Rats
Received: 13 January 2016 / Revised: 21 February 2016 / Accepted: 22 February 2016 / Published: 10 March 2016
Cited by 3 | Viewed by 1971 | PDF Full-text (1993 KB) | HTML Full-text | XML Full-text
Abstract
Domoic acid (DA) is one of the best known marine toxins, causative of important neurotoxic alterations. DA effects are documented both in wildlife and experimental assays, showing that this toxin causes severe injuries principally in the hippocampal area. In the present study we [...] Read more.
Domoic acid (DA) is one of the best known marine toxins, causative of important neurotoxic alterations. DA effects are documented both in wildlife and experimental assays, showing that this toxin causes severe injuries principally in the hippocampal area. In the present study we have addressed the long-term toxicological effects (30 days) of DA intraperitoneal administration in rats. Different histological techniques were employed in order to study DA toxicity in heart, an organ which has not been thoroughly studied after DA intoxication to date. The presence of DA was detected by immunohistochemical assays, and cellular alterations were observed both by optical and transmission electron microscopy. Although histological staining methods did not provide any observable tissue damage, transmission electron microscopy showed several injuries: a moderate lysis of myofibrils and loss of mitochondrial conformation. This is the first time the association between heart damage and the presence of the toxin has been observed. Full article
(This article belongs to the collection Marine and Freshwater Toxins)
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Open AccessReview Perfringolysin O Theta Toxin as a Tool to Monitor the Distribution and Inhomogeneity of Cholesterol in Cellular Membranes
Received: 4 February 2016 / Revised: 26 February 2016 / Accepted: 26 February 2016 / Published: 8 March 2016
Cited by 12 | Viewed by 2617 | PDF Full-text (1288 KB) | HTML Full-text | XML Full-text
Abstract
Cholesterol is an essential structural component of cellular membranes in eukaryotes. Cholesterol in the exofacial leaflet of the plasma membrane is thought to form membrane nanodomains with sphingolipids and specific proteins. Additionally, cholesterol is found in the intracellular membranes of endosomes and has [...] Read more.
Cholesterol is an essential structural component of cellular membranes in eukaryotes. Cholesterol in the exofacial leaflet of the plasma membrane is thought to form membrane nanodomains with sphingolipids and specific proteins. Additionally, cholesterol is found in the intracellular membranes of endosomes and has crucial functions in membrane trafficking. Furthermore, cellular cholesterol homeostasis and regulation of de novo synthesis rely on transport via both vesicular and non-vesicular pathways. Thus, the ability to visualize and detect intracellular cholesterol, especially in the plasma membrane, is critical to understanding the complex biology associated with cholesterol and the nanodomains. Perfringolysin O (PFO) theta toxin is one of the toxins secreted by the anaerobic bacteria Clostridium perfringens and this toxin forms pores in the plasma membrane that causes cell lysis. It is well understood that PFO recognizes and binds to cholesterol in the exofacial leaflets of the plasma membrane, and domain 4 of PFO (D4) is sufficient for the binding of cholesterol. Recent studies have taken advantage of this high-affinity cholesterol-binding domain to create a variety of cholesterol biosensors by using a non-toxic PFO or the D4 in isolation. This review highlights the characteristics and usefulness of, and the principal findings related to, these PFO-derived cholesterol biosensors. Full article
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Open AccessArticle DNA Aptamers against Taiwan Banded Krait α-Bungarotoxin Recognize Taiwan Cobra Cardiotoxins
Received: 31 January 2016 / Revised: 29 February 2016 / Accepted: 29 February 2016 / Published: 5 March 2016
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Abstract
Bungarus multicinctus α-bungarotoxin (α-Bgt) and Naja atra cardiotoxins (CTXs) share a common structural scaffold, and their tertiary structures adopt three-fingered loop motifs. Four DNA aptamers against α-Bgt have been reported previously. Given that the binding of aptamers with targeted proteins depends on structural [...] Read more.
Bungarus multicinctus α-bungarotoxin (α-Bgt) and Naja atra cardiotoxins (CTXs) share a common structural scaffold, and their tertiary structures adopt three-fingered loop motifs. Four DNA aptamers against α-Bgt have been reported previously. Given that the binding of aptamers with targeted proteins depends on structural complementarity, in this study, we investigated whether DNA aptamers against α-Bgt could also recognize CTXs. It was found that N. atra cardiotoxin 3 (CTX3) reduced the electrophoretic mobility of aptamers against α-Bgt. Analysis of the changes in the fluorescence intensity of carboxyfluorescein-labeled aptamers upon binding toxin molecules revealed that CTX3 and α-Bgt could bind the tested aptamers. Moreover, the aptamers inhibited the membrane-damaging activity and cytotoxicity of CTX3. In addition to CTX3, other N. atra CTX isotoxins also bound to the aptamer against α-Bgt. Taken together, our data indicate that aptamers against α-Bgt show cross-reactivity with CTXs. The findings that aptamers against α-Bgt also suppress the biological activities of CTX3 highlight the potential utility of aptamers in regard to the broad inhibition of snake venom three-fingered proteins. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessReview Conversion Ratio between Botox®, Dysport®, and Xeomin® in Clinical Practice
Received: 21 December 2015 / Revised: 23 February 2016 / Accepted: 26 February 2016 / Published: 4 March 2016
Cited by 23 | Viewed by 2798 | PDF Full-text (236 KB) | HTML Full-text | XML Full-text
Abstract
Botulinum neurotoxin has revolutionized the treatment of spasticity and is now administered worldwide. There are currently three leading botulinum neurotoxin type A products available in the Western Hemisphere: onabotulinum toxin-A (ONA) Botox®, abobotulinum toxin-A (ABO), Dysport®, and incobotulinum toxin [...] Read more.
Botulinum neurotoxin has revolutionized the treatment of spasticity and is now administered worldwide. There are currently three leading botulinum neurotoxin type A products available in the Western Hemisphere: onabotulinum toxin-A (ONA) Botox®, abobotulinum toxin-A (ABO), Dysport®, and incobotulinum toxin A (INCO, Xeomin®). Although the efficacies are similar, there is an intense debate regarding the comparability of various preparations. Here we will address the clinical issues of potency and conversion ratios, as well as safety issues such as toxin spread and immunogenicity, to provide guidance for BoNT-A use in clinical practice. INCO was shown to be as effective as ONA with a comparable adverse event profile when a clinical conversion ratio of 1:1 was used. The available clinical and preclinical data suggest that a conversion ratio ABO:ONA of 3:1—or even lower—could be appropriate for treating spasticity, cervical dystonia, and blepharospasm or hemifacial spasm. A higher conversion ratio may lead to an overdosing of ABO. While uncommon, distant spread may occur; however, several factors other than the pharmaceutical preparation are thought to affect spread. Finally, whereas the three products have similar efficacy when properly dosed, ABO has a better cost-efficacy profile. Full article
(This article belongs to the Section Bacterial Toxins)
Open AccessArticle Isolation of Anti-Ricin Protective Antibodies Exhibiting High Affinity from Immunized Non-Human Primates
Received: 6 January 2016 / Revised: 25 February 2016 / Accepted: 26 February 2016 / Published: 3 March 2016
Cited by 16 | Viewed by 1769 | PDF Full-text (951 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Ricin, derived from the castor bean plant Ricinus communis, is one of the most potent and lethal toxins known, against which there is no available antidote. To date, the use of neutralizing antibodies is the most promising post-exposure treatment for ricin intoxication. [...] Read more.
Ricin, derived from the castor bean plant Ricinus communis, is one of the most potent and lethal toxins known, against which there is no available antidote. To date, the use of neutralizing antibodies is the most promising post-exposure treatment for ricin intoxication. The aim of this study was to isolate high affinity anti-ricin antibodies that possess potent toxin-neutralization capabilities. Two non-human primates were immunized with either a ricin-holotoxin- or subunit-based vaccine, to ensure the elicitation of diverse high affinity antibodies. By using a comprehensive set of primers, immune scFv phage-displayed libraries were constructed and panned. A panel of 10 antibodies (five directed against the A subunit of ricin and five against the B subunit) was isolated and reformatted into a full-length chimeric IgG. All of these antibodies were found to neutralize ricin in vitro, and several conferred full protection to ricin-intoxicated mice when given six hours after exposure. Six antibodies were found to possess exceptionally high affinity toward the toxin, with KD values below pM (koff < 1 × 10−7 s−1) that were well correlated with their ability to neutralize ricin. These antibodies, alone or in combination, could be used for the development of a highly-effective therapeutic preparation for post-exposure treatment of ricin intoxication. Full article
(This article belongs to the Section Plant Toxins)
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Open AccessArticle Characterization and Recombinant Expression of Terebrid Venom Peptide from Terebra guttata
Received: 1 January 2016 / Revised: 23 February 2016 / Accepted: 23 February 2016 / Published: 3 March 2016
Cited by 4 | Viewed by 2197 | PDF Full-text (1964 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Venom peptides found in terebrid snails expand the toolbox of active compounds that can be applied to investigate cellular physiology and can be further developed as future therapeutics. However, unlike other predatory organisms, such as snakes, terebrids produce very small quantities of venom, [...] Read more.
Venom peptides found in terebrid snails expand the toolbox of active compounds that can be applied to investigate cellular physiology and can be further developed as future therapeutics. However, unlike other predatory organisms, such as snakes, terebrids produce very small quantities of venom, making it difficult to obtain sufficient amounts for biochemical characterization. Here, we describe the first recombinant expression and characterization of terebrid peptide, teretoxin Tgu6.1, from Terebra guttata. Tgu6.1 is a novel forty-four amino acid teretoxin peptide with a VI/VII cysteine framework (C–C–CC–C–C) similar to O, M and I conotoxin superfamilies. A ligation-independent cloning strategy with an ompT protease deficient strain of E. coli was employed to recombinantly produce Tgu6.1. Thioredoxin was introduced in the plasmid to combat disulfide folding and solubility issues. Specifically Histidine-6 tag and Ni-NTA affinity chromatography were applied as a purification method, and enterokinase was used as a specific cleavage protease to effectively produce high yields of folded Tgu6.1 without extra residues to the primary sequence. The recombinantly-expressed Tgu6.1 peptide was bioactive, displaying a paralytic effect when injected into a Nereis virens polychaete bioassay. The recombinant strategy described to express Tgu6.1 can be applied to produce high yields of other disulfide-rich peptides. Full article
(This article belongs to the Special Issue Venomics, Venom Proteomics and Venom Transcriptomics)
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Open AccessArticle Occurrence of Staphylococcus aureus on Farms with Small Scale Production of Raw Milk Cheeses in Poland
Received: 3 December 2015 / Revised: 19 February 2016 / Accepted: 22 February 2016 / Published: 2 March 2016
Cited by 15 | Viewed by 2068 | PDF Full-text (723 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes the results of a 3-year study on the prevalence, enterotoxinogenicity and resistance to antimicrobials of S. aureus isolated on dairy farms with small scale production of raw cow milk cheeses. The samples of raw milk, semi-finished products and the final [...] Read more.
This paper describes the results of a 3-year study on the prevalence, enterotoxinogenicity and resistance to antimicrobials of S. aureus isolated on dairy farms with small scale production of raw cow milk cheeses. The samples of raw milk, semi-finished products and the final products as well as swabs were collected between 2011 and 2013 from nine dairy farms in Poland. A total of 244 samples were examined, of which 122 (50.0%) were contaminated with S. aureus including 18 of 26 (69.2%) mature cheese samples with log10 CFU g−1 between <1- and 7.41. In swabs collected from the staff and production environment the highest contamination rate with coagulase positive staphylococci (CPS) was detected on hands of cheese makers (4.34 log10 CFU/swab). None of the cheese samples contaminated with CPS contained staphylococcal enterotoxins (SEs). However, 55 of 122 (45.1%) S. aureus isolates possessed SEs genes, mainly (26 of 55; 47.3%) a combination of the sed, sej and ser genes. Furthermore, the sep (15 of 55; 27.3%) as well as seg and sei (9 of 55; 16.4%) genes were also identified. The remaining S. aureus isolates possessed the sea gene (one isolate), the combination of sec, seg and sei (three isolates) as well as the sed, sej, sep and ser markers together (one CPS). Resistance to penicillin (62 of 122 isolates; 50.8%) was the most common among the tested isolates. Some CPS were also resistant to chloramphenicol (7; 5.7%) and tetracycline (5; 4.1%). The obtained results indicated that the analyzed cheeses were safe for consumers. To improve the microbiological quality of traditional cheese products more attention should be paid to animal welfare and hygiene practices during the process of cheese manufacturing in some dairy farms. Full article
(This article belongs to the collection Staphylococcus aureus Toxins)
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Open AccessReview A Review of Bioinsecticidal Activity of Solanaceae Alkaloids
Received: 29 November 2015 / Revised: 22 February 2016 / Accepted: 24 February 2016 / Published: 1 March 2016
Cited by 30 | Viewed by 3240 | PDF Full-text (1057 KB) | HTML Full-text | XML Full-text
Abstract
Only a small percentage of insect species are pests. However, pest species cause significant losses in agricultural and forest crops, and many are vectors of diseases. Currently, many scientists are focused on developing new tools to control insect populations, including secondary plant metabolites, [...] Read more.
Only a small percentage of insect species are pests. However, pest species cause significant losses in agricultural and forest crops, and many are vectors of diseases. Currently, many scientists are focused on developing new tools to control insect populations, including secondary plant metabolites, e.g., alkaloids, glycoalkaloids, terpenoids, organic acids and alcohols, which show promise for use in plant protection. These compounds can affect insects at all levels of biological organization, but their action generally disturbs cellular and physiological processes, e.g., by altering redox balance, hormonal regulation, neuronal signalization or reproduction in exposed individuals. Secondary plant metabolites cause toxic effects that can be observed at both lethal and sublethal levels, but the most important effect is repellence. Plants from the Solanaceae family, which contains numerous economically and ecologically important species, produce various substances that affect insects belonging to most orders, particularly herbivorous insects and other pests. Many compounds possess insecticidal properties, but they are also classified as molluscides, acaricides, nematocides, fungicides and bactericides. In this paper, we present data on the sublethal and lethal toxicity caused by pure metabolites and crude extracts obtained from Solanaceae plants. Pure substances as well as water and/or alcohol extracts cause lethal and sublethal effects in insects, which is important from the economical point of view. We discuss the results of our study and their relevance to plant protection and management. Full article
(This article belongs to the collection Toxicity of Natural Alkaloids)
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Open AccessFeature PaperArticle Paulistine—The Functional Duality of a Wasp Venom Peptide Toxin
Received: 9 December 2015 / Revised: 12 February 2016 / Accepted: 22 February 2016 / Published: 29 February 2016
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Abstract
It has been reported that Paulistine in the venom of the wasp Polybia paulista co-exists as two different forms: an oxidized form presenting a compact structure due to the presence of a disulfide bridge, which causes inflammation through an apparent interaction with receptors [...] Read more.
It has been reported that Paulistine in the venom of the wasp Polybia paulista co-exists as two different forms: an oxidized form presenting a compact structure due to the presence of a disulfide bridge, which causes inflammation through an apparent interaction with receptors in the 5-lipoxygenase pathway, and a naturally reduced form (without the disulfide bridge) that exists in a linear conformation and which also causes hyperalgesia and acts in the cyclooxygenase type II pathway. The reduced peptide was acetamidomethylated (Acm-Paulistine) to stabilize this form, and it still maintained its typical inflammatory activity. Oxidized Paulistine docks onto PGHS2 (COX-2) molecules, blocking the access of oxygen to the heme group and inhibiting the inflammatory activity of Acm-Paulistine in the cyclooxygenase type II pathway. Docking simulations revealed that the site of the docking of Paulistine within the PGHS2 molecule is unusual among commercial inhibitors of the enzyme, with an affinity potentially much higher than those observed for traditional anti-inflammatory drugs. Therefore, Paulistine causes inflammatory activity at the level of the 5-lipooxygenase pathway and, in parallel, it competes with its reduced form in relation to the activation of the cyclooxygenase pathway. Thus, while the reduced Paulistine causes inflammation, its oxidized form is a potent inhibitor of this activity. Full article
(This article belongs to the Special Issue Arthropod Venoms)
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Open AccessReview Botulinum toxin A for the Treatment of Overactive Bladder
Received: 29 January 2016 / Revised: 20 February 2016 / Accepted: 24 February 2016 / Published: 29 February 2016
Cited by 10 | Viewed by 1614 | PDF Full-text (236 KB) | HTML Full-text | XML Full-text
Abstract
The standard treatment for overactive bladder starts with patient education and behavior therapies, followed by antimuscarinic agents. For patients with urgency urinary incontinence refractory to antimuscarinic therapy, currently both American Urological Association (AUA) and European Association of Urology (EAU) guidelines suggested that intravesical [...] Read more.
The standard treatment for overactive bladder starts with patient education and behavior therapies, followed by antimuscarinic agents. For patients with urgency urinary incontinence refractory to antimuscarinic therapy, currently both American Urological Association (AUA) and European Association of Urology (EAU) guidelines suggested that intravesical injection of botulinum toxin A should be offered. The mechanism of botulinum toxin A includes inhibition of vesicular release of neurotransmitters and the axonal expression of capsaicin and purinergic receptors in the suburothelium, as well as attenuation of central sensitization. Multiple randomized, placebo-controlled trials demonstrated that botulinum toxin A to be an effective treatment for patients with refractory idiopathic or neurogenic detrusor overactivity. The urinary incontinence episodes, maximum cystometric capacity, and maximum detrusor pressure were improved greater by botulinum toxin A compared to placebo. The adverse effects of botulinum toxin A, such as urinary retention and urinary tract infection, were primarily localized to the lower urinary tract. Therefore, botulinum toxin A offers an effective treatment option for patients with refractory overactive bladder. Full article
(This article belongs to the Special Issue Botulinum Toxin A on Lower Urinary Tract Dysfunction)
Open AccessArticle Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a, a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan, Oxyuranus temporalis
Received: 22 December 2015 / Revised: 19 February 2016 / Accepted: 19 February 2016 / Published: 29 February 2016
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Abstract
Taipans (Oxyuranus spp.) are elapids with highly potent venoms containing presynaptic (β) and postsynaptic (α) neurotoxins. O. temporalis (Western Desert taipan), a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components [...] Read more.
Taipans (Oxyuranus spp.) are elapids with highly potent venoms containing presynaptic (β) and postsynaptic (α) neurotoxins. O. temporalis (Western Desert taipan), a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da), a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1–1 µM) produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM) was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL) delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM) and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM). α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA2 value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a) as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87%) with other taipan short-chain postsynaptic neurotoxins. Full article
(This article belongs to the Section Animal Venoms)
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Open AccessArticle Aflatoxin M1 in Cow’s Milk: Method Validation for Milk Sampled in Northern Italy
Received: 28 December 2015 / Revised: 10 February 2016 / Accepted: 18 February 2016 / Published: 26 February 2016
Cited by 9 | Viewed by 2481 | PDF Full-text (1832 KB) | HTML Full-text | XML Full-text
Abstract
Aflatoxins (AFs) are mycotoxins produced by some species of Aspergillus. In dairy cows, ingested AFB1 is metabolized into carcinogenic AFM1 which is eliminated through milk, thus posing a risk for consumer health. Here we describe the set, validation, and application of screening [...] Read more.
Aflatoxins (AFs) are mycotoxins produced by some species of Aspergillus. In dairy cows, ingested AFB1 is metabolized into carcinogenic AFM1 which is eliminated through milk, thus posing a risk for consumer health. Here we describe the set, validation, and application of screening (ELISA) and confirmatory (HPLC) tests carried out on milk samples collected through official control of mycotoxin levels in northern Italy over a three-year period (2012–2014). The limit of detection (LOD) was set at 5 ppt and 2 ppt for ELISA and HPLC, respectively, and the limit of quantification (LOQ) was 10 ppt for confirmatory HPLC. A total of 1668 milk samples were analyzed: ELISA identified 36 (2.2%) positive milk samples that were subsequently confirmed by HPLC. The level of AFM1 in the positive samples ranged between 18 ± 2 and 208 ± 27 ppt. Of the total samples, only eight (0.5%) were found non-compliant with the EU regulatory limit (50 ppt; range 74 ± 10 to 208 ± 27 ppt). Use of ELISA and HPLC tests in series allows for high-volume analysis of samples, thus saving time and money while guaranteeing high analytical precision and accuracy. Full article
(This article belongs to the Section Mycotoxins)
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Open AccessArticle Quantitative Determination of Lethal Toxin Proteins in Culture Supernatant of Human Live Anthrax Vaccine Bacillus anthracis A16R
Received: 27 October 2015 / Revised: 4 February 2016 / Accepted: 5 February 2016 / Published: 25 February 2016
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Abstract
Bacillus anthracis (B. anthracis) is the etiological agent of anthrax affecting both humans and animals. Anthrax toxin (AT) plays a major role in pathogenesis. It includes lethal toxin (LT) and edema toxin (ET), which are formed by the combination of protective [...] Read more.
Bacillus anthracis (B. anthracis) is the etiological agent of anthrax affecting both humans and animals. Anthrax toxin (AT) plays a major role in pathogenesis. It includes lethal toxin (LT) and edema toxin (ET), which are formed by the combination of protective antigen (PA) and lethal factor (LF) or edema factor (EF), respectively. The currently used human anthrax vaccine in China utilizes live-attenuated B. anthracis spores (A16R; pXO1+, pXO2−) that produce anthrax toxin but cannot produce the capsule. Anthrax toxins, especially LT, have key effects on both the immunogenicity and toxicity of human anthrax vaccines. Thus, determining quantities and biological activities of LT proteins expressed by the A16R strain is meaningful. Here, we explored LT expression patterns of the A16R strain in culture conditions using another vaccine strain Sterne as a control. We developed a sandwich ELISA and cytotoxicity-based method for quantitative detection of PA and LF. Expression and degradation of LT proteins were observed in culture supernatants over time. Additionally, LT proteins expressed by the A16R and Sterne strains were found to be monomeric and showed cytotoxic activity, which may be the main reason for side effects of live anthrax vaccines. Our work facilitates the characterization of anthrax vaccines components and establishment of a quality control standard for vaccine production which may ultimately help to ensure the efficacy and safety of the human anthrax vaccine A16R. Full article
(This article belongs to the collection Anthrax Toxins)
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Open AccessArticle Cylindrospermopsin Biodegradation Abilities of Aeromonas sp. Isolated from Rusałka Lake
Received: 7 December 2015 / Revised: 9 February 2016 / Accepted: 9 February 2016 / Published: 25 February 2016
Cited by 8 | Viewed by 1471 | PDF Full-text (1367 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The occurrence of the cyanobacterial toxin cylindrospermopsin (CYN) in freshwater reservoirs is a common phenomenon. However, the biodegradation of this toxin in environmental samples has been observed only occasionally. In this work the biodegradation ability of cylindrospermopsin was investigated based on isolates from [...] Read more.
The occurrence of the cyanobacterial toxin cylindrospermopsin (CYN) in freshwater reservoirs is a common phenomenon. However, the biodegradation of this toxin in environmental samples has been observed only occasionally. In this work the biodegradation ability of cylindrospermopsin was investigated based on isolates from lakes with previous cyanotoxin history. Bacterial strains were identified based on the 16S rDNA and rpoD gene comparison. CYN biodegradation was monitored using the HPLC method. The R6 strain identified as Aeromonas sp. was documented as being capable of CYN removal. This biodegradation was dependent on the pH and temperature. Additionally, the stimulation of the growth of the R6 strain in the presence of CYN was indicated. Our discovery supports the hypothesis that (in analogy to the well-known phenomenon of microcystin biodegradation) in lakes dominated by potential CYN-producing cyanobacteria, the processes of microbial utilization of this toxin may occur. Full article
(This article belongs to the Special Issue Bioactivity and Toxicity in Marine Cyanobacteria)
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