• Food Science and Preservation
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• v.22 no.4
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• pp.559-566
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• 2015

The aim of this study was to develop an analytical method for determination of T-2 toxin and HT-2 toxin level in cereals and to survey their levels using LC-MS/MS. The T-2 and HT-2 toxins were simultaneously analyzed by electrospray ionization with a positive ion mode and multiple reaction monitoring (MRM) after filteration and immuno-affinity column clean-up. A matrix-matched standard calibration used for quantification and recoveries of T-2 and HT-3 toxins were in the range of $100.6{\pm}7.2%$ and $96.8{\pm}9.4%$, respectively. Limits of detection and quantification of T-2 and HT-2 toxins were estimated to be 0.5 and $1.5{\mu}g/kg$, respectively. Each repeatability (RSRr) of T-2 and HT-2 toxins was determined to be 0.9~6.0%, and 4.9~6.1%, respectively. Total 115 samples cereals were collected from 9 types of cereals for analysis. The positive percentages of T-2 and HT-2 toxins obtained from collected samples were found to be 72% and 80%, respectively. The contamination level of T-2 toxin and HT-2 toxin in cereals were $37.1{\mu}g/kg$, and $5.4{\mu}g/kg$, respectively. Therefore, this study suggests that the developed method could be an useful analytical method to determine the T-2 and HT-2 toxin level in cereals and the present data could be used as a reference to estimate the risk assessment.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.407-412
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• 2000

Environmental biosensors and related techniques for monitoring organochlorines, endocrine disrupting chemicals and cyanobacterial toxins are described. The practical requirements for an ideal environmental biosensor are analyzed. Specific case studies for environmental applications are reported for triazines, chlorinated phenols, PCBs, microcystins, and endocrine disrupting chemicals. A new promising approach is reported for microcystins and alkylphenols that utilize electrooptical detection.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.1015-1019
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• 2003

A 50 day feeding trial was conducted with White Leghorn (WL) laying hens, 42 weeks old, to determine if feeding of varying levels of aflatoxin (AF), ochratoxin A (OA) or their combinations has any effect on their performance and egg quality parameters. Feeding of $T_4$, $T_7$, $T_8$, $T_9$ and $T_10$ caused significant reduction in feed intake of hens. Hen day egg productions were significantly reduced at all the levels of toxins except 0.5 ppm of AF. Maximum reduction in egg production was noticed at 2 and 4 ppm of AF and OA, respectively. Average body weight and egg weight were not affected by toxin feeding. The feed efficiency in terms of net feed efficiency and feed consumed per dozen egg produced was significantly reduced at higher levels of both the toxins and their combinations. Feed consumption for production of 1 kg egg mass remained uninfluenced due to aflatoxin feeding whereas significant increase in the value of the same was noticed at 4 ppm level of OA and combination of 1 and 2 ppm of AF and 2 and 4 ppm of OA ($T_9$ and $T_10$), respectively. Various levels of OA (1-4 ppm) and all the combination of two toxins ($T_8$, $T_9$ and $T_10$) significantly altered the shape index of eggs in laying hens. The shell thickness was significantly reduced by higher level of AF (2 ppm), OA (2 and 4 ppm) and their combination. Albumen index, Haugh Unit and yolk index remained unchanged due to incorporation of toxins in the diet. It is concluded that AF, OA either singly or in combination at higher levels could depress the performance in terms of egg production and feed efficiency significantly. The egg quality parameters i.e. shape index and shell thickness were also significantly affected.

• BMB Reports
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• v.53 no.5
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• pp.260-265
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• 2020

Scorpion venom comprises a cocktail of toxins that have proven to be useful molecular tools for studying the pharmacological properties of membrane ion channels. HelaTx1, a short peptide neurotoxin isolated recently from the venom of the scorpion Heterometrus laoticus, is a 25 amino acid peptide with two disulfide bonds that shares low sequence homology with other scorpion toxins. HelaTx1 effectively decreases the amplitude of the K⁺ currents of voltage-gated Kv1.1 and Kv1.6 channels expressed in Xenopus oocytes, and was identified as the first toxin member of the κ-KTx5 subfamily, based on a sequence comparison and phylogenetic analysis. In the present study, we report the NMR solution structure of HelaTx1, and the major interaction points for its binding to voltage-gated Kv1.1 channels. The NMR results indicate that HelaTx1 adopts a helix-loop-helix fold linked by two disulfide bonds without any β-sheets, resembling the molecular folding of other cysteine-stabilized helix-loop-helix (Cs α/α) scorpion toxins such as κ-hefutoxin, HeTx, and OmTx, as well as conotoxin pl14a. A series of alanine-scanning analogs revealed a broad surface on the toxin molecule largely comprising positively-charged residues that is crucial for interaction with voltage-gated Kv1.1 channels. Interestingly, the functional dyad, a key molecular determinant for activity against voltage-gated potassium channels in other toxins, is not present in HelaTx1.

• BMB Reports
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• v.39 no.3
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• pp.284-291
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• 2006

In this study, the cDNA of a new peptide from the venom of the scorpion, Buthotus saulcyi, was cloned and sequenced. It codes for a 64 residues peptide (Bsaul1) which shares high sequence similarity with depressant insect toxins of scorpions. The differences between them mainly appear in the loop1 which connects the $\beta$-strand1 to the $\alpha$-helix and seems to be functionally important in long chain scorpion neurotoxins. This loop is three amino acids longer in Bsaul1 compared to other depressant toxins. A comparative amino acid sequence analysis done on Bsaul1 and some of $\alpha$-, $\beta$-, excitatory and depressant toxins of scorpions showed that Bsaul1 contains all the residues which are highly conserved among long chain scorpion neurotoxins. Structural model of Bsaul1 was generated using Ts1 (a $\beta$-toxin that competes with the depressant insect toxins for binding to $Na^+$ channels) as template. According to the molecular model of Bsaul1, the folding of the polypeptide chain is being composed of an anti-parallel three-stranded $\beta$-sheet and a stretch of $\alpha$-helix, tightly bound by a set of four disulfide bridges. A striking similarity in the spatial arrangement of some critical residues was shown by superposition of the backbone conformation of Bsaul1 and Ts1.

• Clinical and Experimental Pediatrics
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• v.56 no.4
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• pp.159-164
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• 2013

Purpose: Indoxyl sulfate and p-cresyl sulfate are important protein-bound uremic retention solutes whose levels can be partially reduced by renal replacement therapy. These solutes originate from intestinal bacterial protein fermentation and are associated with cardiovascular outcomes and chronic kidney disease progression. The aims of this study were to investigate the levels of indoxyl sulfate and p-cresyl sulfate as well as the effect of probiotics on reducing the levels of uremic toxins in pediatric patients on dialysis. Methods: We enrolled 20 pediatric patients undergoing chronic dialysis; 16 patients completed the study. The patients underwent a 12-week regimen of VSL#3, a high-concentration probiotic preparation, and the serum levels of indoxyl sulfate and p-cresyl sulfate were measured before treatment and at 4, 8, and 12 weeks after the regimen by using fluorescence liquid chromatography. To assess the normal range of indoxyl sulfate and p-cresyl sulfate we enrolled the 16 children with normal glomerular filtration rate who had visited an outpatient clinic for asymptomatic microscopic hematuria that had been detected by a school screening in August 2011. Results: The baseline serum levels of indoxyl sulfate and p-cresyl sulfate in the patients on chronic dialysis were significantly higher than those in the children with microscopic hematuria. The baseline serum levels of p-cresyl sulfate in the peritoneal dialysis group were significantly higher than those in the hemodialysis group. There were no significant changes in the levels of these uremic solutes after 12-week VSL#3 treatment in the patients on chronic dialysis. Conclusion: The levels of the uremic toxins p-cresyl sulfate and indoxyl sulfate are highly elevated in pediatric patients on dialysis, but there was no significant effect by probiotics on the reduction of uremic toxins in pediatric dialysis patients. Therefore, studies for other medical intervention to reduce uremic toxins are also necessary in pediatric patients on dialysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.669-674
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• 2017

Paralytic shellfish toxins (PSTs) are produced by marine dinoflagellate phytoplankton Alexandrium spp. and Gymnodinium spp. These toxins accumulate in filter feeding organisms such as bivalves and the ingestion of contaminated shellfish can cause illness in humans. The mouse bioassay (MBA) has been the preferred PST testing method worldwide for more than 50 years. However, this assay has several disadvantages, such as detection limits, non-toxic-profiles, and the ethical issues of using animals. The aim of this study was to establish an alternative to the MBA method for testing for PSTs. We optimized the analysis conditions of a post-column oxidation-high performance liquid chromatography (PCOX-HPLC) method and the Scotia Rapid Test Kit, and then compared the accuracy of these methods to the MBA method. The results demonstrated a strong correlation between the PCOX-HPLC method and the MBA, although the PCOX-HPLC method required expensive equipment and standard material, and was time consuming. The Scotia Rapid Test Kit promises to be a useful tool, as it provided rapid and qualitative results, although the method sometimes gave a false positive result that could not be explained by toxin profiles.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.77-84
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• 2018

In Singapore, biosafety and biosecurity measures are controlled by the Biological Agents and Toxins Act (BATA) and other requirements by regulatory agencies. The law prohibits and otherwise regulates the possession, use, import, transhipment, transfer, and transportation of biological agents, inactivated biological agents, and toxins that are of public health concern. The law also defines the facility requirements for high risk biological agents and toxins. The containment facility (BSL 3) is a minimum requirement to handle biological agents that falls under Schedule 1 (Risk Group 3). The Nanyang Technological University School of Biological Sciences Biosafety Level 3 Facility (NTU-SBS BSL 3) was designed specifically for research involving potential hazardous biological materials. The facility requires yearly re-certification by an approved facility certifier to meet the local requirements and international biosafety standards for a containment facility in many instances. On the other hand, most NTU researchers conduct biological projects involving biological agents with low or moderate risk groups (Risk Groups 1 and 2 or biological agents described in schedule 3 and 4 of BATA) and GMOs, which need only a BSL 2 laboratory. BSL 2 laboratories are yet to be legally certified or registered in Singapore. Institutional Biosafety Committee (IBC) identifies the requirements; defines a minimum standard in the safe control of biological risks and registers all BSL 2 laboratories in the NTU. Therefore, under the guidance of the IBC, the University Biosafety and Biosecurity Programme includes the audit and certification program as a unique and an internal exercise to bring NTU biosafety to a higher level.

• Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.159-164
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• 2013

The mouse bioassay and high performance liquid chromatography (HPLC) post-column oxidation method are different methods of quantifying paralytic shellfish poisoning toxins. In this study, we compared their ability to accurately quantify the toxicity levels in two types of field sample (oysters and mussels) with different toxin profiles for routine regulatory monitoring. A total of 72 samples were analyzed by both methods, 44 of which gave negative results, with readings under the limit of detection of the mouse bioassay ($40{\mu}g/100g$ saxitoxin [STX] eq). In 14 oysters, the major toxin components were gonyautoxin (GTX) 1, -2, -3, -4, -5, decarbamoylgonyautoxin-2 (dcGTX2), and decarbamoylsaxitoxin (dcSTX), while 14 mussels tested positive for dcSTX, GTX2, -3, -4, -5, dcGTX2, neosaxitoxin (NEO), STX, and dcSTX. When the results obtained by both methods were compared in two matrices, a better correlation ($r^2=0.9478$) was obtained for mussels than for oysters ($r^2=0.8244$). Additional studies are therefore needed in oysters to investigate the differences in the results obtained by both methods. Importantly, some samples with toxin levels around the legal limit gave inconsistent results using HPLC-based techniques, which could have a strong economic impact due to enforced harvest area closure. It should therefore be determined if all paralytic shellfish poisoning toxins can be quantified accurately by HPLC, and if the uncertainties of the method lead to doubts regarding regulatory limits.

• Nutrition Research and Practice
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• v.16 no.4
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• pp.435-449
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• 2022

BACKGROUND/OBJECTIVES: Cheonggukjang is a traditional fermented soybean paste with significant health-promoting effects. On the other hand, there have been insufficient studies on the safety and efficacy of Cheonggukjang, which is produced using traditional methods containing toxins and biogenic amines (BAs). This study compared the laxative effect of Cheonggukjang, containing high or low levels of toxins and BAs (HTBC or LTBC) in a loperamide (Lop)-induced constipation mouse model. MATERIALS/METHODS: To induce constipation, Lop (5 mg/kg) was administered orally to ICR mice twice a day for 4 days, and the dose was increased to 8 mg/kg after a 3-day rest period. Cheonggukjang (500 mg/kg, HTBC, or LTBC respectively) was administered for four weeks before the Lop treatment. RESULTS: The number of stools, fecal weight, water contents, gastrointestinal transit, and histological alterations were recovered significantly in the HTBC or LTBC groups. HTBC and LTBC administration did not induce significant changes in body weight, dietary intake, and behavior. The opioid-receptor downstream signaling pathway in colon tissues was also evaluated. The c-Kit, stem cell kinase, and mitogen-activated protein kinases subfamilies, including extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinases, and p38, were all downregulated in the HTBC or LTBC-administered mice colon compared to the Lop group. CONCLUSION: These results show that Cheonggukjang, containing high levels of toxins and BAs, have a similar laxative effect in a mouse model of Lop-induced constipation.