Remco Muntendam - Academia.edu (original) (raw)

Papers by Remco Muntendam

Metabolomics and bioanalysis of terpenoid derived secondary metabolites: Analysis of Cannabis sat... more Metabolomics and bioanalysis of terpenoid derived secondary metabolites: Analysis of Cannabis sativa L. metabolite production and prenylases for cannabinoid production.

Wiley-VCH Verlag GmbH & Co. KGaA eBooks, Apr 17, 2012

Planta Medica, Jul 1, 2012

Journal of Biotechnology, Oct 1, 2012

Journal of the American Oil Chemists' Society, Nov 7, 2019

Upon storage, crude plant oils will form a solid sediment called gum, which consists mainly of ph... more Upon storage, crude plant oils will form a solid sediment called gum, which consists mainly of phospholipids (PL). PL are removed during the production of edible oils by a process called degumming. A higher yield is recognized as a major advantage of enzymatic degumming over traditional processes. Robust and accurate PL quantification methods are needed to develop and monitor enzymatic degumming processes. Several techniques, such as atomic emission spectroscopy, liquid chromatography, and thin-layer chromatography, have been applied for the quantification of PL in edible oils. In the past decade, 31 P NMR spectroscopy has been shown to have advantages over these techniques because of the possibility of the simultaneous, fast, and accurate quantification of different PL directly in the oil. This article demonstrates the application of 31 P NMR spectroscopy as a method for the quantification of all relevant PL and phosphorous-containing degradation products in crude and refined oils. In addition, the validation results show that this method is robust because the limit of detection is as low as 5 μmol/100 g oil. Variations of less than 5% were obtained for all P-containing compounds present in the oils at concentrations above 100 μmol/100 g oil.

Cannabinoid research has gained a renenewed interest by both the public and scientist. Focus is m... more Cannabinoid research has gained a renenewed interest by both the public and scientist. Focus is mainly directed to the medicinal activities, as reported for various cannabinoid structures. This thesis focusses on prenyl-derived secondary metabolites with main focus on cannabinoids. Firstly the production patterns and production location were investigated for standardiozed cultivated medicinal C.sativa variants. Metabolic profiling discriminated variants during the complete cultivation. Moreover, the densities and plant distribution of three classes of trichoma were reported and analyzed for their cannabinoid profile. Next an alternative enzyme for, the major cannabinoid precursor, cannabigerolic acid production was investigated. By providing a new hypothesis for the prenylation mechanism, evidence is provided for activity improvement on important substrates for cannabinoid production. Last the potential of X.dendrohous to produce terpene derived compounds after recombinant engineeri...

In contrast to the protein field, a much smaller number of RNA tertiary structures has been asses... more In contrast to the protein field, a much smaller number of RNA tertiary structures has been assessed by X-ray crystallography, NMR spectroscopy and cryo-EM, and deposited in structural data banks. In view of the rapidly growing access to RNA secondary structures their 3D structure prediction is in great demand in the RNA community. Only a few programs and web-accessible tools have been proposed for semi-automated and automated prediction of the RNA tertiary structure. Automated methods make use of the coarse-grained and atomic-level molecular dynamics, internal coordinate space dynamics, fragment assembly and comparative modelling using templates. They vary considerably in terms of the required input data (RNA sequence, secondary structure, conformational data or structural templates), structure prediction quality across different RNA sizes and computation time. Recently we have developed a novel approach for the fully automated RNA 3D structure prediction from the userdefined secon...

Topics in Heterocyclic Chemistry, 2007

ABSTRACT Cannabinoids and in particular the main psychoactive Δ9-THC are promising substances for... more ABSTRACT Cannabinoids and in particular the main psychoactive Δ9-THC are promising substances for the development of new drugs and are of high importance in biomedicine and pharmacy. This review gives an overview of the chemical properties of Δ9-THC, its synthesis on industrial scale, and the synthesis of important metabolites. The biosynthesis of cannabinoids in Cannabis sativa is extensively described in addition to strategies for optimization of this plant for cannabinoid employment in medicine. The metabolism of Δ9-THC in humans is shown and, based on this, analytical procedures for cannabinoids and their metabolites in human forensic samples as well as in C.sativa will be discussed. Furthermore, some aspects of medicinal indications for Δ9-THC and its ways of administration are described. Finally, some synthetic cannabinoids and their importance in research and medicine are delineated.

Drug Discovery and Clinical Applications, 2012

Trichomes of Cannabis sativa have been reported as the main site of cannabinoids production. A co... more Trichomes of Cannabis sativa have been reported as the main site of cannabinoids production. A comprehensive study of cannabinoids was performed on capitate-stalked and capitate-sessile trichomes, and on capitate-stalked glands and stems harvested by laser microdissection (LMD) during flowering time (week 4 -8). LC-MS and cryogenic NMR analysis were used for qualitative and quantitative assessment of cannabinoids in the collected cells.  9 -tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA) and cannabigerolic acid (CBCA) were identified as the major constituents in the all tested samples, while  9 -tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabigerol (CBG) were present in less quantity. Cannabichromene (CBC) and cannabinol (CBN) were detected as minor compounds only in intact capitate-stalked trichomes in week 8. Based on the cannabinoids levels, discrimination of capitate-stalked and capitate-sessile trichomes at flowering time was possible. The study demonst...

The iron binding siderophore pyoverdine constitutes a major adaptive factor contributing to both ... more The iron binding siderophore pyoverdine constitutes a major adaptive factor contributing to both virulence and survival in fluorescent pseudomonads. For decades, pyoverdine production has allowed the identification and classification of fluorescent and nonfluorescent pseudomonads. Here, we demonstrate that PvdP, a periplasmic enzyme of previously unknown function, is a tyrosinase required for the maturation of the pyoverdine chromophore in Pseudomonas aeruginosa. PvdP converts the nonfluorescent ferribactin, containing two iron binding groups, into a fluorescent pyoverdine, forming a strong hexadentate complex with ferrous iron, by three consecutive oxidation steps. PvdP represents the first characterized member of a small family of tyrosinases present in fluorescent pseudomonads that are required for siderophore maturation and are capable of acting on large peptidic substrates.

Proceedings of the National Academy of Sciences, 2010

Pantothenate kinase–associated neurodegeneration (PKAN), a progressive neurodegenerative disorder... more Pantothenate kinase–associated neurodegeneration (PKAN), a progressive neurodegenerative disorder, is associated with impairment of pantothenate kinase function. Pantothenate kinase is the first enzyme required for de novo synthesis of CoA, an essential metabolic cofactor. The pathophysiology of PKAN is not understood, and there is no cure to halt or reverse the symptoms of this devastating disease. Recently, we and others presented a PKAN Drosophila model, and we demonstrated that impaired function of pantothenate kinase induces a neurodegenerative phenotype and a reduced lifespan. We have explored this Drosophila model further and have demonstrated that impairment of pantothenate kinase is associated with decreased levels of CoA, mitochondrial dysfunction, and increased protein oxidation. Furthermore, we searched for compounds that can rescue pertinent phenotypes of the Drosophila PKAN model and identified pantethine. Pantethine feeding restores CoA levels, improves mitochondrial ...

Proceedings of the National Academy of Sciences, 2014

Significance Resistance toward commonly used antibiotics is becoming a serious issue in the fight... more Significance Resistance toward commonly used antibiotics is becoming a serious issue in the fight against bacterial pathogens. One promising strategy lies in the interference of bacterial quorum sensing by the hydrolysis of the signaling molecules. In this study, we present a structure-aided computational design approach to alter the substrate specificity of the quorum-quenching acylase PvdQ. Introduction of two point mutations in residues lining the active site led to a switch in substrate specificity, rendering the enzyme highly active toward C8-HSL and thereby reducing virulence caused by Burkholderia cenocepacia . Thus, this work not only provides a structural insight into the substrate specificity of quorum-quenching acylases but also indicates their potential in the fight against specific bacterial pathogens.

Planta Medica, 2009

We are excited to present a program featuring a roster of internationally recognized experts and ... more We are excited to present a program featuring a roster of internationally recognized experts and researchers in the field of botanicals. We wish to extend our thanks to our speakers for their willingness to participate in and contribute to the success of the meeting. We invite you to visit the website of the National Center for Natural Products Research at http://www. pharmacy.olemiss.edu/ncnpr to learn more about our research program. Oxford and the Ole Miss campus are a beautiful setting, and we hope you will get to explore them, especially if this is your first time to visit here. If there is anything we can do to make your visit more enjoyable, please contact us.