The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
David E. Thompson - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of the Long-Term Storage Stability of the Cyanide Antidote: Dimethyl Trisulfide and Degradation Product Identification
ACS omega, 2020Co-Authors: Indika K. Warnakula, Márton Kiss, Afshin Ebrahimpour, Ramesha D. Gaspe Ralalage, Chathuranga C. Hewa-rahinduwage, Christian T. Rios, Kyler D. Kelley, Ashley C. Whiteman, David E. ThompsonAbstract:This study reports the long-term storage stability of a formulation of the cyanide (CN) antidote Dimethyl Trisulfide (DMTS). The F3-formulated DMTS was stored in glass ampules at 4, 22, and 37 °C. ...
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Methemoglobin Forming Effect of Dimethyl Trisulfide in Mice
Hemoglobin, 2018Co-Authors: Márton Kiss, Ilona Petrikovics, David E. ThompsonAbstract:Dimethyl Trisulfide (DMTS) is a natural organic Trisulfide that has been patented as a promising antidotal candidate against cyanide (CN). The primary mode of action of DMTS is as a sulfur donor th...
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Sealing Effects on the Storage Stability of the Cyanide Antidotal Candidate, Dimethyl Trisulfide
Drugs in R&D, 2017Co-Authors: Loránd Kiss, Ilona Petrikovics, Márton Kiss, Anna Duke, Kristof Kovacs, Tibor Barcza, David E. ThompsonAbstract:Background Dimethyl Trisulfide (DMTS) is a highly lipid-soluble cyanide (CN) antidote candidate molecule. In prior studies with various US FDA-approved co-solvents, surfactants, and their combinations, aqueous solutions containing 15% polysorbate 80 (Poly80) were found to effectively solubilize DMTS in formulations for intramuscular administration. However, DMTS formulated in 15% aqueous Poly80 solutions showed gradual losses over time when stored in vials with septum-based seals.
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from the cover in vitro and in vivo blood brain barrier penetration studies with the novel cyanide antidote candidate Dimethyl Trisulfide in mice
Toxicological Sciences, 2017Co-Authors: Loránd Kiss, James Ross, Denise Brown, Brooke Mendenhall, Valerie Coronado, Alexandra Bocsik, Fruzsina R Walter, Sarah R Crews, Jana Lowry, David E. ThompsonAbstract:Recent in vitro and in vivo studies highlight the strong potential of Dimethyl Trisulfide (DMTS) as an antidote for cyanide (CN) intoxication. Due to its high oxygen demand, the brain is one of the main target organs of CN. The blood-brain barrier (BBB) regulates the uptake of molecules into the brain. In the literature, there is no data about the ability of DMTS to penetrate the BBB. Therefore, our aim was to test the in vitro BBB penetration of DMTS and its in vivo pharmacokinetics in blood and brain. The in vitro BBB penetration of DMTS was measured by using a parallel artificial membrane permeability assay (BBB-PAMPA), and a triple BBB co-culture model. The pharmacokinetics was investigated in a mouse model by following the DMTS concentration in blood and brain at regular time intervals following intramuscular administration. DMTS showed high penetrability in both in vitro systems (apparent permeability coefficients: BBB-PAMPA 11.8 × 10-6 cm/s; cell culture 158 × 10-6 cm/s) without causing cell toxicity and leaving the cellular barrier intact. DMTS immediately absorbed into the blood after the intramuscular injection (5 min), and rapidly penetrated the brain of mice (10 min). In addition to the observed passive diffusion in the in vitro studies, the contribution of facilitated and/or active transport to the measured high permeability of DMTS in the pharmacokinetic studies can be hypothesized. Earlier investigations demonstrating the antidotal efficacy of DMTS against CN together with the present results highlight the promise of DMTS as a brain-protective CN antidote.
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reaction of Dimethyl Trisulfide with hemoglobin
Chemical Research in Toxicology, 2017Co-Authors: Xinmei Dong, Ilona Petrikovics, Loránd Kiss, David E. ThompsonAbstract:Dimethyl Trisulfide (DMTS) is a promising antidotal candidate for cyanide intoxication. DMTS acts as a sulfur donor in the conversion of cyanide to the less-toxic thiocyanate. The alternate reaction pathways of DMTS in the blood are not well understood. We report changes in the hemoglobin absorption spectrum upon reaction with DMTS. These changes closely match those induced by the known methemoglobin former, sodium nitrite. The kinetics of methemoglobin formation with DMTS is slower than with sodium nitrite. These results support the hypothesis that a potentially significant side-reaction of the therapeutically administered DMTS is the oxidization of hemoglobin to methemoglobin.
Gary A. Rockwood - One of the best experts on this subject based on the ideXlab platform.
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a novel aqueous Dimethyl Trisulfide formulation is effective at low doses against cyanide toxicity in non anesthetized mice and rats
Clinical Toxicology, 2021Co-Authors: Dennean S. Lippner, Diane M Hildenberger, Melissa O Rhoomes, Jessica N Winborn, H Dixon, J Mcdonough, Gary A. RockwoodAbstract:Background Cyanide (CN) is a metabolic poison that is capable of intoxicating individuals through accidental or intentional means. With high concentration exposures, death can occur in minutes. In cases of mass casualty exposures, there is a need for a rapid-acting countermeasure capable of being administered in a short period of time in a pre-hospital setting to treat victims. Objective These studies evaluate the safety and efficacy of a novel aqueous formulation of Dimethyl Trisulfide (DMTS) as an intramuscular (IM) CN countermeasure using non-anesthetized rodent models. Methods Non-anesthetized rodents (mice and rats) were exposed to hydrogen cyanide (HCN) or potassium cyanide (KCN) along with immediate IM 10% DMTS treatment or vehicle treatment. Survival and other parameters, such as the time to recovery and assessment of clinical toxic signs (e.g., gasping, loss of righting reflex, convulsions, etc.), were quantified to determine the effectiveness of 10% DMTS treatment (12.5, 25, 75 mg/kg IM) compared to vehicle control treatment. A rat KCN delayed-treatment model with a 15-minute treatment delay was also utilized to simulate a real-life exposure/treatment scenario with 10% DMTS treatment. The stability of the 10% DMTS formulation was also assessed. Results A 25 mg/kg IM dose of 10% DMTS exhibits potent efficacy against subcutaneous (SC) KCN challenge in both mice and rats and inhalational HCN exposure in mice. 10% DMTS treatment also shortens the time to recovery in rats using a delayed-treatment model. Conclusion IM treatment with 10% DMTS improves survival and clinical outcomes in non-anesthetized rodent models of acute CN toxicity. Additionally, the use of an SC KCN delayed-treatment model in rats is advised to assess the performance of a candidate CN countermeasure in a more realistic exposure/treatment scenario.
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Behavioural and physiological assessments of Dimethyl Trisulfide treatment for acute oral sodium cyanide poisoning.
Basic & clinical pharmacology & toxicology, 2019Co-Authors: Nathaniel C. Rice, Gary A. Rockwood, Dennean S. Lippner, Noah A. Rauscher, William L. Wilkins, Todd M. MyersAbstract:Sodium cyanide (NaCN) is a commonly and widely used industrial and laboratory chemical that is highly toxic. Its availability and rapid harmful/lethal effects combine to make cyanide a potential foodborne/waterborne intentional-poisoning hazard. Effective antidotes to cyanide poisoning are currently approved only for intravenous administration. Therefore, an effective cyanide antidote that can be administered intramuscularly in pre-hospital and/or mass-casualty settings is needed. Dimethyl Trisulfide (DMTS) is a naturally occurring substance used as a flavour enhancer in foods. DMTS has shown antidotal efficacy in cyanide poisoning and is thought to act as both a sulphur donor and partial methaemoglobin inducer. In this study, an intramuscular injection of DMTS (6.25-200 mg/kg) was given to rats 1 minute after an oral dose of NaCN (98.2 mg/kg; twice the median lethal dose) to test the antidotal efficacy and safety of DMTS treatment. Toxic signs and survival were examined along with behavioural function (up to 30 hour after ingestion) using a previously established operant behavioural model. A large range of DMTS doses (6.25-100 mg/kg) increased survival after oral cyanide poisoning, and the lower DMTS doses (6.25-25 mg/kg) also proved to be behaviourally and physiologically safe. Larger DMTS doses (50-200 mg/kg) produced side effects (ie, inflammation and limping) that were more severe and protracted than those observed at lower DMTS doses. The 25 mg/kg DMTS proved to be the most efficacious (increasing survival from 20% to 75%) and also produced minimal side effects (eg, inflammation) that resolved within 24-72 hour. Thus, DMTS shows promise as an intramuscularly administered cyanide antidote useful for prompt pre-hospital or mass-casualty emergency medical treatment.
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intramuscular Dimethyl Trisulfide efficacy in a large swine model of acute severe cyanide toxicity
Clinical Toxicology, 2019Co-Authors: Tara B Hendryhofer, Gary A. Rockwood, Dennean S. Lippner, Sari B Mahon, Matthew Brenner, Alyssa E Witeof, Vikhyat S BebartaAbstract:Background: Cyanide is a deadly compound used as a terrorist agent. Current FDA approved antidotes require intravenous administration, limiting their utility in a mass casualty scenario. Dimethyl t...
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Analysis of potential cyanide antidote, Dimethyl Trisulfide, in whole blood by dynamic headspace gas chromatography-mass spectroscopy.
Journal of chromatography. A, 2019Co-Authors: Subrata Bhadra, Gary A. Rockwood, Zhiling Zhang, Wenhui Zhou, Fredrick Ochieng, Dennean S. Lippner, Brian A. LogueAbstract:Abstract Cyanide is a rapidly acting and highly toxic chemical. It inhibits cytochrome c oxidase in the mitochondrial electron transport chain, resulting in cellular hypoxia, cytotoxic anoxia and potentially death. In order to overcome challenges associated with current cyanide antidotes, Dimethyl Trisulfide (DMTS), which converts cyanide to less toxic thiocyanate in vivo, has gained much attention recently as a promising next-generation cyanide antidote. While there are three analysis methods available for DMTS, they each have significant disadvantages. Hence, in this study, a dynamic headspace (DHS) gas chromatography–mass spectroscopy method was developed for the analysis of DMTS from rabbit whole blood. The method is extremely simple, involving only acidification of a blood sample, addition of an internal standard (DMTS-d6) and DHS-GC–MS analysis. The method produced a limit of detection of 0.04 μM for DMTS with dynamic range from 0.2 to 50 μM. Inter- and intraassay accuracy (100 ± 15% and 100 ± 9%, respectively), and precision (
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monitoring dose response of cyanide antidote Dimethyl Trisulfide in rabbits using diffuse optical spectroscopy
Journal of Medical Toxicology, 2018Co-Authors: Jangwoen Lee, Ilona Petrikovics, Gary A. Rockwood, Brian A. Logue, Erica Manandhar, Changhoon Han, Vik Bebarta, Sari B Mahon, Tanya Burney, Matthew BrennerAbstract:Cyanide (CN) poisoning is a serious chemical threat from accidental or intentional exposures. Current CN exposure treatments, including direct binding agents, methemoglobin donors, and sulfur donors, have several limitations. Dimethyl Trisulfide (DMTS) is capable of reacting with CN to form the less toxic thiocyanate with high efficiency, even without the sulfurtransferase rhodanese. We investigated a soluble DMTS formulation with the potential to provide a continuous supply of substrate for CN detoxification which could be delivered via intramuscular (IM) injection in a mass casualty situation. We also used non-invasive technology, diffuse optical spectroscopy (DOS), to monitor physiologic changes associated with CN exposure and reversal. Thirty-six New Zealand white rabbits were infused with a lethal dose of sodium cyanide solution (20 mg/60 ml normal saline). Animals were divided into three groups and treated with saline, low dose (20 mg), or high dose (150 mg) of DMTS intramuscularly. DOS continuously assessed changes in tissue hemoglobin concentrations and cytochrome c oxidase redox state status throughout the experiment. IM injection of DMTS increased the survival in lethal CN poisoning. DOS demonstrated that high-dose DMTS (150 mg) reversed the effects of CN exposure on cytochrome c oxidase, while low dose (20 mg) did not fully reverse effects, even in surviving animals. This study demonstrated potential efficacy for the novel approach of supplying substrate for non-rhodanese mediated sulfur transferase pathways for CN detoxification via intramuscular injection in a moderate size animal model and showed that DOS was useful for optimizing the DMTS treatment.
Atsuko Isogai - One of the best experts on this subject based on the ideXlab platform.
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mutagenesis breeding and characterization of sake yeast strains with low production of Dimethyl Trisulfide precursor
Journal of Bioscience and Bioengineering, 2020Co-Authors: Jun Makimoto, Atsuko Isogai, Ryoko Kanda, Tsutomu Fujii, Kou Wakabayashi, Toyohisa Inoue, Yuriko Ikeda, Takashi NakaeAbstract:Dimethyl Trisulfide (DMTS) is one of the main components responsible for hineka, the aroma associated with deteriorated Japanese sake during storage. The molecule 1,2-dihydroxy-5-(methylsulfinyl)pentan-3-one (DMTS-P1) has been previously identified as a major precursor compound of DMTS. Furthermore, it had been suggested that the yeast methionine salvage pathway is involved in the production of DMTS-P1. In sake brewing tests, DMTS-P1 and the DMTS producing potential (DMTS-pp; DMTS amount of sake after accelerated storage) were significantly reduced in mde1 or mri1 strain, which lack genes of the methionine salvage pathway. Industrial use of the gene-disrupting strains may not be accepted in the Japanese food industry. In order to obtain mde1 or mri1 mutants, we established a method to screen 5'-methylthioadenosine (MTA) non-utilizing strains using minimum culture medium containing methionine or MTA by ethyl methanesulfonate (EMS) mutagenesis with methionine-auxotrophic sake yeast haploid. As expected, mde1 and mri1 mutants were identified among the obtained mutants by an established screening method. The obtained strains had poor fermentation ability in sake brewing tests, so back-crossing was performed on the mutants to obtain mde1 or mri1 homozygous mutants. These strains had improved brewing characteristics, and DMTS-P1 and the DMTS-pp of the produced sake were significantly lower than those of the parent strains. These strains are expected to contribute to improving the maintenance of sake quality during storage.
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construction of sake yeast with low production of Dimethyl Trisulfide precursor by a self cloning method
Journal of Bioscience and Bioengineering, 2018Co-Authors: Yuriko Ikeda, Atsuko Isogai, Ryoko Kanda, Yuta Moriyoshi, Kazuhiro Iwashita, Tsutomu FujiiAbstract:Dimethyl Trisulfide (DMTS) is the primary component responsible for “hineka”, the stale aroma of Japanese sake. Deletion of the MRI1 or MDE1 gene of sake yeast, encoding 5′-methylthioribose-1-phosphate isomerase and 5′-methylthioribulose-1-phosphate dehydratase, respectively, has been reported to greatly reduce the amount of DMTS precursor (DMTS-P1) in sake and to suppress the formation of DMTS during storage. In this study, we constructed sake yeast strains lacking MRI1 gene function by a self-cloning method. Two methods were applied: in one, a stop codon was introduced in the MRI1 ORF by point mutation; in the other, the entire MRI1 ORF was deleted from the genome. In both methods, a plasmid vector containing drug-resistance and counter-selectable markers was used to introduce the mutation. We successfully obtained the strains, which did not contain the plasmid sequences, by both methods. Small-scale sake brewing tests using these SC strains (strains obtained by the self-cloning method) found that DMTS-P1 was hardly detected in sake brewed with SC strains, and DMTS production after sake storage was greatly reduced as compared with the parent strain. The components of brewed sake were almost the same between the SC and parent strains. These results suggest that SC strains can produce sake with higher flavor stability without changing the sake brewing properties.
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yeast cell lysis enhances Dimethyl Trisulfide formation in sake
Journal of Bioscience and Bioengineering, 2014Co-Authors: Nahoko Nishibori, Atsuko Isogai, Kei Sasaki, Yuta Okimori, Muneyoshi Kanai, Osamu Yamada, Tsutomu Fujii, Nami GotoyamamotoAbstract:The present study showed that the lysis of yeast cells and subsequent release of cell contents in sake mash accelerated Dimethyl Trisulfide (DMTS) formation. Among these, heat unstable and relatively high molecular weight compounds were assumed to be enzymes; thus, enzymatic reactions probably contribute to DMTS formation.
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statistical analysis of sake preparation conditions and Dimethyl Trisulfide formation
Journal of Bioscience and Bioengineering, 2014Co-Authors: Kei Sasaki, Atsuko Isogai, Nahoko Nishibori, Muneyoshi Kanai, Osamu Yamada, Nami Gotoyamamoto, Tsutomu FujiiAbstract:Dimethyl Trisulfide (DMTS) is known to be responsible for hineka, an off-flavor that develops during storage, in sake. Previous studies have attempted to elucidate the mechanism of DMTS formation during sake storage, but the mechanism underlying DMTS formation remains unclear. In this study, we determined the sake-preparation conditions that affect DMTS formation. We analyzed 76 sake samples immediately after filtration, which were donated by sake-producing companies. We measured the DMTS concentration in sake after 7 days of storage at 70°C (DMTS-pp) using gas chromatography/mass spectrometry. In the statistical analysis, DMTS-pp was set as the objective variable, whereas the preparation conditions and analytical results for sake were set as the explanatory variables. We used multiple linear regression (MLR) analysis with a stepwise method and partial least squares regression (PLSR) to analyze the data. The statistical analysis showed that the significant factors for DMTS-pp were the average temperature in the moromi mash (Temp ave), the total daily temperature in the moromi mash (Temp sum), the concentration of sulfur-containing amino acids in sake, and the Zn concentration in sake. These factors explained 63.4% of the variance in DMTS-pp according to the MLR analysis and 64.2% according to the PLSR analysis. Further MLR analysis showed that Temp ave in early stage and Temp sum in later stage were important factors for DMTS-pp. This result suggests that the rice dissolution caused by high Temp ave in early stage and yeast cell lysis caused by high Temp sum in later stage contribute to high DMTS-pp.
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involvement of methionine salvage pathway genes of saccharomyces cerevisiae in the production of precursor compounds of Dimethyl Trisulfide dmts
Journal of Bioscience and Bioengineering, 2013Co-Authors: Kou Wakabayashi, Atsuko Isogai, Daisuke Watanabe, Akiko Fujita, Shigetoshi SudoAbstract:Dimethyl Trisulfide (DMTS) is one of the components responsible for the unpalatable aroma of stale Japanese sake, called “hineka”. Recently, a precursor compound of DMTS, 1,2-dihydroxy-5-(methylsulfinyl)pentan-3-one (DMTS-P1), was identified. It was speculated that the yeast methionine salvage pathway (MTA cycle) might participate in the formation of DMTS-P1, because the chemical structure of DMTS-P1 was similar to one of the intermediate compounds of that pathway. Here, we carried out sake brewing tests using laboratory yeast strains with disrupted MTA cycle genes and found that DMTS-P1 was hardly produced by Δmeu1, Δmri1, and Δmde1 strains. Furthermore, the DMTS producing potential (production of DMTS during storage of sake) decreased in sake made with Δmri1 and Δmde1. We constructed sake yeast strains with a disrupted MRI1 or MDE1 gene and confirmed a decline in the DMTS-P1 content and DMTS producing potential of sake made with these disruptants. The results of sake brewing tests using MTA cycle disruptants suggested that SPE2 is responsible for the production of DMTS precursors other than DMTS-P1: although the DMTS-P1 content was higher in Δspe2 sake than in Δmri1 or Δmde1 sake, the DMTS producing potential of Δspe2 sake was as low as that of Δmri1 or Δmde1 sake. Sake brewing tests using BY4743 Δspe2 Δmri1 double disruptants revealed that the DMTS producing potential was further decreased as compared with the Δspe2 or Δmri1 single disruptant. These results suggest that MRI1, MDE1, and SPE2 are promising targets for breeding yeast to suppress the formation of DMTS during storage of sake.
Gabor Pozsgai - One of the best experts on this subject based on the ideXlab platform.
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Dimethyl Trisulfide diminishes traumatic neuropathic pain acting on trpa1 receptors in mice
International Journal of Molecular Sciences, 2021Co-Authors: Agnes Dombi, Csenge Santa, Istvan Batai, Viktoria Kormos, Angela Kecskes, Valeria Tekus, Krisztina Pohoczky, Kata Bolcskei, Erika Pinter, Gabor PozsgaiAbstract:Pharmacotherapy of neuropathic pain is still challenging. Our earlier work indicated an analgesic effect of Dimethyl Trisulfide (DMTS), which was mediated by somatostatin released from nociceptor nerve endings acting on SST4 receptors. Somatostatin release occurred due to TRPA1 ion channel activation. In the present study, we investigated the effect of DMTS in neuropathic pain evoked by partial ligation of the sciatic nerve in mice. Expression of the mRNA of Trpa1 in murine dorsal-root-ganglion neurons was detected by RNAscope. Involvement of TRPA1 ion channels and SST4 receptors was tested with gene-deleted animals. Macrophage activity at the site of the nerve lesion was determined by lucigenin bioluminescence. Density and activation of microglia in the spinal cord dorsal horn was verified by immunohistochemistry and image analysis. Trpa1 mRNA is expressed in peptidergic and non-peptidergic neurons in the dorsal root ganglion. DMTS ameliorated neuropathic pain in Trpa1 and Sstr4 WT mice, but not in KO ones. DMTS had no effect on macrophage activity around the damaged nerve. Microglial density in the dorsal horn was reduced by DMTS independently from TRPA1. No effect on microglial activation was detected. DMTS might offer a novel therapeutic opportunity in the complementary treatment of neuropathic pain.
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role of transient receptor potential ankyrin 1 ion channel and somatostatin sst4 receptor in the antinociceptive and anti inflammatory effects of sodium polysulfide and Dimethyl Trisulfide
Frontiers in Endocrinology, 2018Co-Authors: Istvan Batai, Erika Pinter, Adam Horvath, Zsuzsanna Helyes, Gabor PozsgaiAbstract:Transient Receptor Potential Ankyrin 1 (TRPA1) non-selective ligand-gated cation channels are mostly expressed in primary sensory neurons. Polysulfides are Janus-faced substances interacting with numerous target proteins and associated to both protective and detrimental processes. Activation of TRPA1 in sensory neurons, consequent somatostatin (SOM) liberation and action on sst4 receptors have recently emerged as mediators of the antinociceptive effect of organic Trisulfide Dimethyl Trisulfide (DMTS). In the frame of the present study we set out to compare the participation of this mechanism in antinociceptive and anti-inflammatory effects of inorganic sodium polysulfide (POLY) and DMTS in carrageenan-evoked hind paw inflammation. Inflammation of murine hind paws was induced by intraplantar injection of carrageenan (3% in 30 µL saline). Animals were treated intraperitoneally with POLY (17 µmol/kg) or DMTS (250 µmol/kg) or their respective vehicles 30 min prior paw challenge and 6 times afterwards every 60 min. Mechanical pain threshold and swelling of the paws were measured by dynamic plantar aesthesiometry and plethysmometry at 2, 4 and 6 h after initiation of inflammation. Myeloperoxidase (MPO) activity in the hind paws were detected 6 h after challenge by luminescent imaging. Mice genetically lacking TRPA1 ion channels, sst4 receptors and their wild-type counterparts were used to examine the participation of these proteins in POLY and DMTS effects. POLY counteracted carrageenan-evoked mechanical hyperalgesia in a TRPA1 and sst4 receptor-dependent manner. POLY did not influence paw swelling and MPO activity. DMTS ameliorated all examined inflammatory parameters. Mitigation of mechanical hyperalgesia and paw swelling by DMTS were mediated through sst4 receptors. These effects were present in TRPA1 knockout animals, too. DMTS inhibited MPO activity with no participation of the sensory neuron-SOM axis. While antinociceptive effects of POLY are transmitted by activation of peptidergic nerves via TRPA1, release of SOM and its effect on sst4 receptors, those of DMTS partially rely on SOM release triggered by other routes. SOM is responsible for the inhibition of paw swelling by DMTS, but TRPA1 does not contribute to its release. Modulation of MPO activity by DMTS is independent of TRPA1 and sst4.
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analgesic effect of Dimethyl Trisulfide in mice is mediated by trpa1 and sst4 receptors
Nitric Oxide, 2017Co-Authors: Gabor Pozsgai, Maja Payrits, Eva Saghy, Reka Sebestyenbatai, Elise Steen, Eva Szőke, Zoltan Sandor, Margit Solymar, Andras Garami, Peter OrvosAbstract:TRPA1 receptors are calcium-permeable ligand-gated channels expressed in primary sensory neurons and involved in inflammation and pain. Activation of these neurons might have analgesic effect. Suggested mechanism of analgesic effect mediated by TRPA1 activation is the release of somatostatin (SOM) and its action on sst4 receptors. In the present study analgesic effect of TRPA1 activation on primary sensory neurons by organic Trisulfide compound Dimethyl Trisulfide (DMTS) presumably leading to SOM release was investigated. Opening of TRPA1 by DMTS in CHO cells was examined by patch-clamp and fluorescent Ca2+ detection. Ca2+ influx upon DMTS administration in trigeminal ganglion (TRG) neurons of TRPA1 receptor wild-type (WT) and knockout (KO) mice was detected by ratiometric Ca2+ imaging. SOM release from sensory nerves of murine skin was assessed by radioimmunoassay. Analgesic effect of DMTS in mild heat injury-induced mechanical hyperalgesia was examined by dynamic plantar aesthesiometry. Regulatory role of DMTS on deep body temperature (Tb) was measured by thermocouple thermometry with respirometry and by telemetric thermometry. DMTS produced TRPA1-mediated currents and elevated [Ca2+]i in CHO cells. Similar data were obtained in TRG neurons. DMTS released SOM from murine sensory neurons TRPA1-dependently. DMTS exerted analgesic effect mediated by TRPA1 and sst4 receptors. DMTS-evoked hypothermia and hypokinesis were attenuated in freely-moving TRPA1 KO animals. Our study has presented original evidence regarding analgesic action of DMTS which might be due to TRPA1-mediated SOM release from sensory neurons and activation of sst4 receptors. DMTS could be a novel analgesic drug candidate.
Tsutomu Fujii - One of the best experts on this subject based on the ideXlab platform.
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mutagenesis breeding and characterization of sake yeast strains with low production of Dimethyl Trisulfide precursor
Journal of Bioscience and Bioengineering, 2020Co-Authors: Jun Makimoto, Atsuko Isogai, Ryoko Kanda, Tsutomu Fujii, Kou Wakabayashi, Toyohisa Inoue, Yuriko Ikeda, Takashi NakaeAbstract:Dimethyl Trisulfide (DMTS) is one of the main components responsible for hineka, the aroma associated with deteriorated Japanese sake during storage. The molecule 1,2-dihydroxy-5-(methylsulfinyl)pentan-3-one (DMTS-P1) has been previously identified as a major precursor compound of DMTS. Furthermore, it had been suggested that the yeast methionine salvage pathway is involved in the production of DMTS-P1. In sake brewing tests, DMTS-P1 and the DMTS producing potential (DMTS-pp; DMTS amount of sake after accelerated storage) were significantly reduced in mde1 or mri1 strain, which lack genes of the methionine salvage pathway. Industrial use of the gene-disrupting strains may not be accepted in the Japanese food industry. In order to obtain mde1 or mri1 mutants, we established a method to screen 5'-methylthioadenosine (MTA) non-utilizing strains using minimum culture medium containing methionine or MTA by ethyl methanesulfonate (EMS) mutagenesis with methionine-auxotrophic sake yeast haploid. As expected, mde1 and mri1 mutants were identified among the obtained mutants by an established screening method. The obtained strains had poor fermentation ability in sake brewing tests, so back-crossing was performed on the mutants to obtain mde1 or mri1 homozygous mutants. These strains had improved brewing characteristics, and DMTS-P1 and the DMTS-pp of the produced sake were significantly lower than those of the parent strains. These strains are expected to contribute to improving the maintenance of sake quality during storage.
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construction of sake yeast with low production of Dimethyl Trisulfide precursor by a self cloning method
Journal of Bioscience and Bioengineering, 2018Co-Authors: Yuriko Ikeda, Atsuko Isogai, Ryoko Kanda, Yuta Moriyoshi, Kazuhiro Iwashita, Tsutomu FujiiAbstract:Dimethyl Trisulfide (DMTS) is the primary component responsible for “hineka”, the stale aroma of Japanese sake. Deletion of the MRI1 or MDE1 gene of sake yeast, encoding 5′-methylthioribose-1-phosphate isomerase and 5′-methylthioribulose-1-phosphate dehydratase, respectively, has been reported to greatly reduce the amount of DMTS precursor (DMTS-P1) in sake and to suppress the formation of DMTS during storage. In this study, we constructed sake yeast strains lacking MRI1 gene function by a self-cloning method. Two methods were applied: in one, a stop codon was introduced in the MRI1 ORF by point mutation; in the other, the entire MRI1 ORF was deleted from the genome. In both methods, a plasmid vector containing drug-resistance and counter-selectable markers was used to introduce the mutation. We successfully obtained the strains, which did not contain the plasmid sequences, by both methods. Small-scale sake brewing tests using these SC strains (strains obtained by the self-cloning method) found that DMTS-P1 was hardly detected in sake brewed with SC strains, and DMTS production after sake storage was greatly reduced as compared with the parent strain. The components of brewed sake were almost the same between the SC and parent strains. These results suggest that SC strains can produce sake with higher flavor stability without changing the sake brewing properties.
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yeast cell lysis enhances Dimethyl Trisulfide formation in sake
Journal of Bioscience and Bioengineering, 2014Co-Authors: Nahoko Nishibori, Atsuko Isogai, Kei Sasaki, Yuta Okimori, Muneyoshi Kanai, Osamu Yamada, Tsutomu Fujii, Nami GotoyamamotoAbstract:The present study showed that the lysis of yeast cells and subsequent release of cell contents in sake mash accelerated Dimethyl Trisulfide (DMTS) formation. Among these, heat unstable and relatively high molecular weight compounds were assumed to be enzymes; thus, enzymatic reactions probably contribute to DMTS formation.
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statistical analysis of sake preparation conditions and Dimethyl Trisulfide formation
Journal of Bioscience and Bioengineering, 2014Co-Authors: Kei Sasaki, Atsuko Isogai, Nahoko Nishibori, Muneyoshi Kanai, Osamu Yamada, Nami Gotoyamamoto, Tsutomu FujiiAbstract:Dimethyl Trisulfide (DMTS) is known to be responsible for hineka, an off-flavor that develops during storage, in sake. Previous studies have attempted to elucidate the mechanism of DMTS formation during sake storage, but the mechanism underlying DMTS formation remains unclear. In this study, we determined the sake-preparation conditions that affect DMTS formation. We analyzed 76 sake samples immediately after filtration, which were donated by sake-producing companies. We measured the DMTS concentration in sake after 7 days of storage at 70°C (DMTS-pp) using gas chromatography/mass spectrometry. In the statistical analysis, DMTS-pp was set as the objective variable, whereas the preparation conditions and analytical results for sake were set as the explanatory variables. We used multiple linear regression (MLR) analysis with a stepwise method and partial least squares regression (PLSR) to analyze the data. The statistical analysis showed that the significant factors for DMTS-pp were the average temperature in the moromi mash (Temp ave), the total daily temperature in the moromi mash (Temp sum), the concentration of sulfur-containing amino acids in sake, and the Zn concentration in sake. These factors explained 63.4% of the variance in DMTS-pp according to the MLR analysis and 64.2% according to the PLSR analysis. Further MLR analysis showed that Temp ave in early stage and Temp sum in later stage were important factors for DMTS-pp. This result suggests that the rice dissolution caused by high Temp ave in early stage and yeast cell lysis caused by high Temp sum in later stage contribute to high DMTS-pp.