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Samuel D Offei, Hadi D Arman, Mirza Oais Baig, Lazaro S Chavez, Carlos A Paladini, Francis K Yoshimoto
Cholic acid is the endogenous 12α-hydroxylated bile acid, which possesses enhanced cholesterol absorption properties compared to its 12-desoxy counterpart, chenodeoxycholic acid. The oxysterol 12α-hydroxylase enzyme is cytochrome P450 8B1 (P450 8B1), which regioselectively and stereoselectively incorporates the 12α-hydroxy group in 7α-hydroxycholest-4-en-3-one, the biosynthetic precursor of cholic acid. Despite the vital role of P450 8B1 activity in cardiovascular health, research studies of other 12α-hydroxy steroid derivatives are rare...
December 2018: Steroids
Ekaterina Yu Bezsudnova, Tatiana N Stekhanova, Anna V Popinako, Tatiana V Rakitina, Alena Yu Nikolaeva, Konstantin M Boyko, Vladimir O Popov
Substrate and reaction promiscuity is a remarkable property of some enzymes and facilitates the adaptation to new metabolic demands in the evolutionary process. Substrate promiscuity is also a basis for protein engineering for biocatalysis. However, molecular principles of enzyme promiscuity are not well understood. Even for the widely studied PLP-dependent transaminases of class III, the reliable prediction of the biocatalytically important amine transaminase activity is still difficult if the desired activity is unrelated to the natural activity...
November 2018: Applied Microbiology and Biotechnology
Carrie J Finno, Krista E Estell, Laramie Winfield, Scott Katzman, Matthew H Bordbari, Erin N Burns, Andrew D Miller, Birgit Puschner, Cecilia K Tran, Libin Xu
BACKGROUND: Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is a neurodegenerative disorder affecting genetically predisposed foals maintained on an α-tocopherol (α-TOH) deficient diet. Currently no antemortem diagnostic test for eNAD/EDM is available. HYPOTHESIS: Because α-TOH deficiency is associated with increased lipid peroxidation, it was hypothesized that F2 -isoprostanes (F2 IsoP), F4 -neuroprostanes (F4 NP) and oxysterols derived from free radical oxidation would be increased in the cerebrospinal fluid (CSF) and neural tissue of eNAD/EDM affected horses and could serve as potential biomarkers for disease...
September 2018: Journal of Veterinary Internal Medicine
Xiu Tian, Ju-Xin Ruan, Jin-Quan Huang, Chang-Qing Yang, Xin Fang, Zhi-Wen Chen, Hui Hong, Ling-Jian Wang, Ying-Bo Mao, Shan Lu, Tian-Zhen Zhang, Xiao-Ya Chen
Gossypol and related sesquiterpene aldehydes in cotton function as defense compounds but are antinutritional in cottonseed products. By transcriptome comparison and coexpression analyses, we identified 146 candidates linked to gossypol biosynthesis. Analysis of metabolites accumulated in plants subjected to virus-induced gene silencing (VIGS) led to the identification of four enzymes and their supposed substrates. In vitro enzymatic assay and reconstitution in tobacco leaves elucidated a series of oxidative reactions of the gossypol biosynthesis pathway...
June 5, 2018: Proceedings of the National Academy of Sciences of the United States of America
Alessandra Crusco, Cinzia Bordoni, Anand Chakroborty, Kezia C L Whatley, Helen Whiteland, Andrew D Westwell, Karl F Hoffmann
The plant-derived, diterpenoid 7-keto-sempervirol was recently reported to display moderate activity against larval stages of Schistosoma mansoni (IC50  = 19.1 μM) and Fasciola hepatica (IC50  = 17.7 μM), two related parasitic blood and liver flukes responsible for the neglected tropical diseases schistosomiasis and fascioliasis, respectively. Here, we aimed to increase the potency of 7-keto-sempervirol by total synthesis of 30 structural analogues. Subsequent screening of these new diterpenoids against juvenile and adult lifecycle stages of both parasites as well as the human HepG2 liver cell line and the bovine MDBK kidney cell line revealed structure-activity relationship trends...
May 25, 2018: European Journal of Medicinal Chemistry
A Garolla, I Šabović, S Tescari, L De Toni, M Menegazzo, I Cosci, V De Filippis, M Giarola, C Foresta
Membrane cholesterol removal appears a key step for the gain of fertility potential during sperm maturation. However, the membrane sterol pattern in sperm cells from infertile patients, with impaired sperm parameters, has been poorly investigated. To elucidate a causative link between sperm membrane composition in male fertility, here we have investigated the levels of cholesterol and its oxidized derivatives 7β-hydroxycholesterol and 7-keto-cholesterol in sixteen infertile patients with oligo-asthenozoospermia and 16 normozoospermic (N) fertile subjects...
March 2018: Andrology
Francis K Yoshimoto, Hadi D Arman, Wendell P Griffith, Fangzhi Yan, Daniel J Wherritt
7α-Hydroxypregnenolone is an endogenous neuroactive steroid that stimulates locomotor activity. A synthesis of 7α-hydroxypregnenolone from pregnenolone, which takes advantage of an orthogonal protecting group strategy, is described. In detail, the C7-position was oxidized with CrO3 and 3,5-dimethylpyrazole to yield a 7-keto steroid intermediate. The resulting 7-ketone was stereoselectively reduced to the 7α-hydroxy group with lithium tri-sec-butylborohydride. In contrast, reduction of the same 7-ketone intermediate with NaBH4 resulted in primarily the 7β-hydroxy epimer...
December 2017: Steroids
Leslie J Donato, Alan Lueke, Stacy M Kenyon, Jeffrey W Meeusen, Michael Camilleri
BACKGROUND: Imbalance of bile acids (BA) homeostasis in the gastrointestinal tract can lead to chronic diarrhea or constipation when BA in the colon are in excess or low, respectively. Since both disturbances of bowel function can result from other etiologies, identifying BA imbalance is important to tailor treatment strategies. Serum concentrations of 7-alpha-hydroxy-4-cholesten-3-one (7aC4), a precursor in bile acid synthesis, reflect BA homeostasis. Here we describe a method to accurately measure serum 7aC4 and evaluate the clinical utility in patients with diarrhea or constipation phenotypes...
February 2018: Clinical Biochemistry
Yuguang Lin, Diny Knol, María Menéndez-Carreño, Raymond Baris, Hans-Gerd Janssen, Elke A Trautwein
Plant sterol (PS) oxidation products (POP) derived from sitosterol and campesterol were measured in 15 foods cooked with liquid margarine without (control) and with added 7.5% PS. POP were analyzed using a GC-MS method. PS liquid vs. control margarine resulted in a higher median POP content per food portion (1.35mg, range 0.08-13.20mg versus 0.23mg, 0.06-0.90mg), a lower PS oxidation rate (0.63 vs. 1.29%) and lower oxidation susceptibility of sitosterol vs. campesterol. POP formation was highest in shallow-fried potatoes with PS liquid margarine (64...
February 15, 2018: Food Chemistry
Saisudha Koka, Min Xia, Yang Chen, Owais M Bhat, Xinxu Yuan, Krishna M Boini, Pin-Lan Li
The NLRP3 inflammasome has been reported to be activated by atherogenic factors, whereby endothelial injury and consequent atherosclerotic lesions are triggered in the arterial wall. However, the mechanisms activating and regulating NLRP3 inflammasomes remain poorly understood. The present study tested whether acid sphingomyelinase (ASM) and ceramide associated membrane raft (MR) signaling platforms contribute to the activation of NLRP3 inflammasomes and atherosclerotic lesions during hypercholesterolemia. We found that 7-ketocholesterol (7-Keto) or cholesterol crystal (ChC) markedly increased the formation and activation of NLRP3 inflammasomes in mouse carotid arterial endothelial cells (CAECs), as shown by increased colocalization of NLRP3 with ASC or caspase-1, enhanced caspase-1 activity and elevated IL-1β levels, which were markedly attenuated by mouse Asm siRNA, ASM inhibitor- amitriptyline, and deletion of mouse Asm gene...
October 2017: Redox Biology
Neha Sharma, KeangOK Baek, Huong T T Phan, Naofumi Shimokawa, Masahiro Takagi
Amyloid beta (Aβ) is a peptide responsible for the development of Alzheimer's disease (AD). Misfolding and accumulation of endogenous Aβ can lead to neural cell apoptosis through endoplasmic reticulum (ER) stress. Added exogenous Aβ can also result in ER stress, leading to neurotoxicity and apoptosis, which is identical to that caused by the endogenous peptide. We have speculated that the endocytic transport of Aβ causes ER stress and have previously shown that the oxysterol, in particular, 7-ketocholesterol (7-keto) induces more surface interaction between Aβ-42 and Jurkat cells than cholesterol...
June 2017: FEBS Open Bio
Yuguang Lin, Diny Knol, Iris Valk, Vincent van Andel, Silvia Friedrichs, Dieter Lütjohann, Karel Hrncirik, Elke A Trautwein
Fat-based products like vegetable oils and margarines are commonly used for cooking, which may enhance oxidation of plant sterols (PS) present therein, leading to the formation of PS oxidation products (POP). The present study aims to assess the kinetics of POP formation in six different fat-based products. Vegetable oils and margarines without and with added PS (7.5-7.6% w/w) in esterified form were heated in a Petri-dish at temperatures of 150, 180 and 210°C for 8, 12 and 16min. PS and POP were analysed using GC-FID and GC-MS-SIM, respectively...
October 2017: Chemistry and Physics of Lipids
Carlo Barnaba, Maria Teresa Rodríguez-Estrada, Giovanni Lercker, Hugo Sergio García, Ilce Gabriela Medina-Meza
In this work we studied the effect of polyunsaturated fatty acids (PUFAs) methyl esters on cholesterol photo-induced oxidation. The oxidative routes were modeled with a chemical reaction network (CRN), which represents the first application of CRN to the oxidative degradation of a food-related lipid matrix. Docosahexaenoic acid (DHA, T-I), eicosapentaenoic acid (EPA, T-II) and a mixture of both (T-III) were added to cholesterol using hematoporphyrin as sensitizer, and were exposed to a fluorescent lamp for 48h...
December 2016: Steroids
Nur Ahmad Hussin, Ruvini U Pathirana, Sahar Hasim, Swetha Tati, Jessica A Scheib-Owens, Kenneth W Nickerson
Due to the increased number of immunocompromised patients, infections with the pathogen Candida albicans have significantly increased in recent years. C. albicans transition from yeast to germ tubes is one of the essential factors for virulence. In this study we noted that Lee's medium, commonly used to induce filamentation, contained 500-fold more biotin than needed for growth and 40-fold more biotin than is typically added to growth media. Thus, we investigated the effects of excess biotin on growth rate and filamentation by C...
September 21, 2016: Microorganisms
T A Mori, K D Croft, I B Puddey, L J Beilin
Cholesterol oxidation products have been demonstrated to possess a wide variety of biological properties and have been implicated in playing an important role in the development of atherosclerosis. We have developed an analytical method using capillary gas chromatography-mass spectrometry (GC-MS) for the analysis of cholesterol oxidation products in low-density lipoprotein (LDL). The method uses programmed multiple selected ion monitoring (SIM), providing enhanced sensitivity and accuracy of peak detection over full-scan mass spectra...
February 1996: Redox Report: Communications in Free Radical Research
Sabine Baumgartner, Ronald P Mensink, Els De Smet, Maurice Konings, Susana Fuentes, Willem M de Vos, Jogchum Plat
Information regarding dietary effects on plasma oxyphytosterol concentrations as well as on the origin of oxyphytosterols is scarce. We hypothesized that plant sterols are oxidized in the intestinal lumen, mediated by microbial activity, followed by uptake into the circulation. To address this hypothesis, we carried out, a randomized, double blind, crossover study in 13 healthy subjects, who consumed for 3 weeks control and plant stanol ester enriched margarines (3.0g/d plant stanols) separated by a 4-week wash-out period...
May 2017: Journal of Steroid Biochemistry and Molecular Biology
Gonzalo Alba, María Edith Reyes-Quiróz, Javier Sáenz, Isabel Geniz, Juan Jiménez, José Martín-Nieto, Elizabeth Pintado, Francisco Sobrino, Consuelo Santa-María
PURPOSE: Oxysterols are cholesterol-oxygenated derivatives generated in the organism and also present in foods because of cholesterol oxidation during processing and storage. They are the natural ligands of liver X receptors (LXRs) and are generally recognized as hypocholesterolemic and anti-inflammatory molecules although this latter property is still controversial. Most oxysterol studies have been performed in macrophages, whereas the effects of oxysterols in neutrophils are poorly known...
December 2016: European Journal of Nutrition
Yuguang Lin, Diny Knol, María Menéndez-Carreño, Wendy A M Blom, Joep Matthee, Hans-Gerd Janssen, Elke A Trautwein
Plant sterols (PS) in foods are subject to thermal oxidation to form PS oxidation products (POP). This study measured POP contents of 19 foods prepared by typical household baking and cooking methods using margarines without (control) and with 7.5% added PS (as 12.5% PS-esters, PS-margarine). Median POP contents per portion size of cooked foods were 0.57 mg (range 0.05-1.11 mg) with control margarine versus 1.42 mg (range 0.08-20.5 mg) with PS-margarine. The oxidation rate of PS (ORP) was 0.50% (median) with the PS-margarine and 3...
January 27, 2016: Journal of Agricultural and Food Chemistry
Hoh-Gyu Hahn, Jung-Sup Choi, Hee Kyung Lim, Kee-In Lee, In Taek Hwang
The chemical validation of a potential herbicide target was investigated with 8-amino-7-oxononanoate synthase (AONS, also known as 7-keto-8-aminopelargonate synthase, KAPAS) and triazolyl phenyl disulfide derivatives in vitro and in vivo. AONS activity was completely inhibited by these synthesized compounds, with an IC50 of 48 to 592μM in vitro. Forty five-day old Arabidopsis thaliana plants were completely killed by representative compound KHG23844 {N-(2-fluorophenyl)-3-(phenyldisulphanyl)-1H-1,2,4-triazole-1-carboxamide} at the application rate of 250gha(-1) of foliar treatment in greenhouse conditions...
November 2015: Pesticide Biochemistry and Physiology
Mohamed Fawzy Ramadan
Fried foods, both deep-fried and pan-fried, are enjoyed by people worldwide. Frying is one of the main factors leading to formation of phytosterols (PS) oxidation products (POP) in vegetable oils. The aim of this study was to measure the oxidation of β-sitosterol (24α-ethyl-5-cholesten-3β-ol) and campesterol (24α-methyl-5-cholesten-3β-ol) in commercial sunflower oil (SFO) during deep- and pan-frying of French fries for different periods (30, 60, 120 and 240 min). The total amount of PS in SFO was 4732 μg/g, wherein the major PS were β-sitosterol and campesterol...
October 2015: Journal of Food Science and Technology
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