scholarly journals verA Gene is Involved in the Step to Make the Xanthone Structure of Demethylsterigmatocystin in Aflatoxin Biosynthesis

2020 ◽  
Vol 21 (17) ◽  
pp. 6389
Author(s):  
Hongmei Zeng ◽  
Jingjing Cai ◽  
Hidemi Hatabayashi ◽  
Hiroyuki Nakagawa ◽  
Hiromitsu Nakajima ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Molecular Mass ◽  
Culture Medium ◽  
The Other ◽  
Aflatoxin Biosynthesis ◽  
Liquid Chromatography Mass Spectrometry ◽  
Fluorescent Substance ◽  
Key Enzyme ◽  
Versicolorin A

In the biosynthesis of aflatoxin, verA, ver-1, ordB, and hypA genes of the aflatoxin gene cluster are involved in the pathway from versicolorin A (VA) to demethylsterigmatocystin (DMST). We herein isolated each disruptant of these four genes to determine their functions in more detail. Disruptants of ver-1, ordB, and hypA genes commonly accumulated VA in their mycelia. In contrast, the verA gene disruptant accumulated a novel yellow fluorescent substance (which we named HAMA) in the mycelia as well as culture medium. Feeding HAMA to the other disruptants commonly caused the production of aflatoxins B1 (AFB1) and G1 (AFG1). These results indicate that HAMA pigment is a novel aflatoxin precursor which is involved at a certain step after those of ver-1, ordB, and hypA genes between VA and DMST. HAMA was found to be an unstable substance to easily convert to DMST and sterigmatin. A liquid chromatography-mass spectrometry (LC-MS) analysis showed that the molecular mass of HAMA was 374, and HAMA gave two close major peaks in the LC chromatogram in some LC conditions. We suggest that these peaks correspond to the two conformers of HAMA; one of them would be selectively bound on the substrate binding site of VerA enzyme and then converted to DMST. VerA enzyme may work as a key enzyme in the creation of the xanthone structure of DMST from HAMA.

scholarly journals Evaluation on Intestinal Permeability of Phlorotannins Using Caco-2 Cell Monolayers

2022 ◽  
Vol 17 (1) ◽  
pp. 1934578X2110704
Author(s):  
Naoki Murata ◽  
Saki Keitoku ◽  
Hideo Miyake ◽  
Reiji Tanaka ◽  
Toshiyuki Shibata
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
The Other ◽  
Intestinal Epithelial ◽  
Liquid Chromatography Mass Spectrometry ◽  
Apparent Permeability ◽  
Cell Monolayers ◽  
Intestinal Membrane ◽  
Small Intestinal ◽  
Conjugated Metabolites

Among the phlorotannins of seaweed polyphenols, eckols which have a dibenzodioxin linkage are known to have various physiological functions. The purpose of this study was to investigate the intestinal epithelial absorption of eckols using Caco-2 cell monolayers of the small intestinal membrane model. Each compound permeated from the apical (AP) side to the basolateral (BL) side in the monolayers was identified and quantitated by liquid chromatography-mass spectrometry with electrospray ionization. In the transport assays using five types of eckols (eckol, fucofuroeckol A, phlorofucofuroeckol A, dieckol, and 8,8'-bieckol), only the monomeric eckol showed limited transepithelial absorption with relatively small apparent permeability values (0.30  ±  0.04  ×  10−8 cm/s). Analyzing the Hanks’ balanced salt solution in the receiver on the BL side showed that phloroglucinol was detected in all experimental sections using eckols, and it's concentration increased with time over the course of the incubation. The other molecules corresponding to the unconjugated and conjugated metabolites of eckols were not detected in the AP and BL sides through the assays. These results suggest that eckols, including monomeric eckol, may be decomposed into phloroglucinol in the intestinal epithelium and the resulting phloroglucinol permeates to the BL side.

scholarly journals Imbalanced Kynurenine Pathway in Schizophrenia

2014 ◽  
Vol 7 ◽  
pp. IJTR.S16800 ◽  
Author(s):  
Magdalena E. Kegel ◽  
Maria Bhat ◽  
Elisabeth Skogh ◽  
Martin Samuelsson ◽  
Kristina Lundberg ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cerebrospinal Fluid ◽  
Liquid Chromatography ◽  
Quinolinic Acid ◽  
Kynurenic Acid ◽  
Kynurenine Pathway ◽  
The Other ◽  
Healthy Controls ◽  
Liquid Chromatography Mass Spectrometry ◽  
Csf Levels

Several studies suggest a role for kynurenic acid (KYNA) in the pathophysiology of schizophrenia. It has been proposed that increased brain KYNA levels in schizophrenia result from a pathological shift in the kynurenine pathway toward enhanced KYNA formation, away from the other branch of the pathway leading to quinolinic acid (QUIN). Here we investigate the levels of QUIN in cerebrospinal fluid (CSF) of patients with schizophrenia and healthy controls, and relate those to CSF levels of KYNA and other kynurenine metabolites from the same individuals. CSF QUIN levels from stable outpatients treated with olanzapine (n = 22) and those of controls (n = 26) were analyzed using liquid chromatography-mass spectrometry. No difference in CSF QUIN levels between patients and controls was observed (20.6 ± 1.5 nM vs. 18.2 ± 1.1 nM, P = 0.36). CSF QUIN was positively correlated to CSF kynurenine and CSF KYNA in patients but not in controls. The CSF QUIN/KYNA ratio was lower in patients than in controls ( P = 0.027). In summary, the present study offers support for an over-activated and imbalanced kynurenine pathway, favoring the production of KYNA over QUIN in patients with schizophrenia.

scholarly journals Detection and confirmation of the ring-opened carboxylic acid metabolite of a new synthetic opioid furanylfentanyl

2020 ◽  
Author(s):  
Tatsuyuki Kanamori ◽  
Yuki Okada ◽  
Hiroki Segawa ◽  
Tadashi Yamamuro ◽  
Kenji Kuwayama ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Liquid Chromatography ◽  
Carboxylic Acid ◽  
Culture Medium ◽  
Human Hepatocytes ◽  
Opioid Epidemic ◽  
Liquid Chromatography Mass Spectrometry ◽  
Metabolic Fate ◽  
Acid Metabolite

Abstract Purpose Recently, the opioid epidemic has become a serious problem, particularly in North America and Europe. The aim of this study was to clarifyQuery the metabolic fate of a new synthetic opioid furanylfentanyl. Methods The metabolism of furanylfentanyl was investigated by incubating fresh human hepatocytes with 10 µM furanylfentanyl at 37 °C for 48 h in an atmosphere of 5% CO2. After incubation, the culture medium was deproteinized and analyzed by liquid chromatography/mass spectrometry. Results On the chromatogram, four metabolites of furanylfentanyl were presumably detected: 4´-hydroxy-furanylfentanyl, β-hydroxy-furanylfentanyl, 4´-hydroxy-3´-methoxy-furanylfentanyl, and a ring-opened carboxylic acid metabolite. These newly found metabolites of furanylfentanyl were then definitely identified using chemically synthesized authentic standards. Conclusions Four metabolites of furanylfentanyl were newly identified. Although it has been proposed over recent years that a dihydrodiol metabolite, which has the same molecular weight as the ring-opened carboxylic acid metabolite, is formed from furanylfentanyl, this study demonstrated that the ring-opened carboxylic acid metabolite, rather than the dihydrodiol metabolite, is formed from furanylfentanyl.

scholarly journals Flavonoids From the Flowers and Leaves of the Himalayan Megacodon stylophorus (Gentianaceae)

2021 ◽  
Vol 16 (2) ◽  
pp. 1934578X2199226
Author(s):  
Tsukasa Iwashina ◽  
Rinchen Yangzom ◽  
Hari Prasad Devkota ◽  
Takayuki Mizuno
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
The Other ◽  
Liquid Chromatography Mass Spectrometry ◽  
The Family ◽  
First Time ◽  
Layer Chromatography

Five flavonol O-glycosides and 4 C-glycosylflavones were isolated from the flowers of the Himalayan Megacodon stylophorus (Gentianaceae). They were characterized as quercetin 3- O-glucoside (1), quercetin 3- O-rutinoside (2), kaempferol 3- O-glucoside (3), isorhamnetin 3- O-glucoside (4) and kaempferol 3,7-di- O-glucoside (5) (flavonols), and isovitexin (6), isoorientin (7), isovitexin X″- O-arabinoside (8) and isovitexin 4′- O-glucoside (9) ( C-glycosylflavones) by ultraviolet, liquid chromatography-mass spectrometry, acid hydrolysis, nuclear magnetic resonance, and/or high-performance liquid chromatography and thin-layer chromatography comparisons with authentic samples. On the other hand, 5 C-glycosylflavones were isolated from the leaves and identified as 6, 7, 9, vitexin (10), and orientin (11). Although many C-glycosylflavones and xanthones have been reported from Gentianaceae species, flavonols are minor occurrence in the family. Flavonoids were reported from the Megacodon species for the first time.

Sign in / Sign up

Export Citation Format

Share Document