scholarly journals Using MALDI-FTICR-MS Imaging to Track Low-Molecular-Weight Aromatic Derivatives of Fungal Decayed Wood

2021 ◽  
Vol 7 (8) ◽  
pp. 609
Author(s):  
Dušan Veličković ◽  
Mowei Zhou ◽  
Jonathan S. Schilling ◽  
Jiwei Zhang
Keyword(s):  
Molecular Weight ◽  
Plant Biomass ◽  
Oxidative Degradation ◽  
Brown Rot ◽  
Low Molecular Weight ◽  
Imaging Method ◽  
Ion Cyclotron Resonance ◽  
Fticr Ms ◽  
Ms Imaging ◽  
Fenton Reagents

Low-molecular-weight (LMW) aromatics are crucial in meditating fungal processes for plant biomass decomposition. Some LMW compounds are employed as electron donors for oxidative degradation in brown rot (BR), an efficient wood-degrading strategy in fungi that selectively degrades carbohydrates but leaves modified lignins. Previous understandings of LMW aromatics were primarily based on “bulk extraction”, an approach that cannot fully reflect their real-time functions during BR. Here, we applied an optimized molecular imaging method that combines matrix-assisted laser desorption ionization (MALDI) with Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS) to directly measure the temporal profiles of BR aromatics as Rhodonia placenta decayed a wood wafer. We found that some phenolics were pre-existing in wood, while some (e.g., catechin-methyl ether and dihydroxy-dimethoxyflavan) were generated immediately after fungal activity. These pinpointed aromatics might be recruited to drive early BR oxidative mechanisms by generating Fenton reagents, Fe2+ and H2O2. As BR progressed, ligninolytic products were accumulated and then modified into various aromatic derivatives, confirming that R. placenta depolymerizes lignin. Together, this work confirms aromatic patterns that have been implicated in BR fungi, and it demonstrates the use of MALDI-FTICR-MS imaging as a new approach to monitor the temporal changes of LMW aromatics during wood degradation.

scholarly journals The termite fungal cultivar Termitomyces combines diverse enzymes and oxidative reactions for plant biomass conversion

2021 ◽  
Author(s):  
Felix Schalk ◽  
Cene Gostinčar ◽  
Nina B. Kreuzenbeck ◽  
Benjamin H. Conlon ◽  
Elisabeth Sommerwerk ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Biomass Conversion ◽  
Degradation Mechanism ◽  
Oxidative Degradation ◽  
Ligninolytic Enzymes ◽  
Brown Rot ◽  
Dicarboxylic Acids ◽  
Lignocellulose Degradation ◽  
Redox Shuttle ◽  
Phenolic Polymer

AbstractMacrotermitine termites have domesticated fungi in the genus Termitomyces as their primary food source using pre-digested plant biomass. To access the full nutritional value of lignin-enriched plant biomass, the termite-fungus symbiosis requires the depolymerization of this complex phenolic polymer. While most previous work suggests that lignocellulose degradation is accomplished predominantly by the fungal cultivar, our current understanding of the underlying biomolecular mechanisms remains rudimentary. Here, we provide conclusive OMICs and activity-based evidence that Termitomyces partially depolymerizes lignocellulose through the combined actions of high-redox potential oxidizing enzymes (laccases, aryl-alcohol oxidases and a manganese peroxidase), the production of extracellular H2O2 and Fenton-based oxidative degradation, which is catalyzed by a newly described 2-methoxybenzoquinone/hydroquinone redox shuttle system and mediated by secreted chelating dicarboxylic acids. In combination, our approaches reveal a comprehensive depiction of how the efficient biomass degradation mechanism in this ancient insect agricultural symbiosis is accomplished through a combination of white- and brown-rot mechanisms.ImportanceFungus-growing termites have perfected the decomposition of recalcitrant plant biomass to access valuable nutrients by engaging in a tripartite symbiosis with complementary contributions from a fungal mutualist and a co-diversified gut microbiome. This complex symbiotic interplay makes them one of the most successful and important decomposers for carbon cycling in Old World ecosystems. To date, most research has focused on the enzymatic contributions of microbial partners to carbohydrate decomposition. Here we provide genomic, transcriptomic and enzymatic evidence that Termitomyces also employs redox mechanisms, including diverse ligninolytic enzymes and a Fenton-based hydroquinone-catalyzed lignin-degradation mechanism, to break down lignin-rich plant material. Insights into these efficient decomposition mechanisms open new sources of efficient ligninolytic agents applicable for energy generation from renewable sources.

Novel Method for Preparation of Low Molecular Weight Natural Rubber Latex

1998 ◽  
Vol 71 (4) ◽  
pp. 795-802 ◽  
Author(s):  
Jitladda Tangpakdee ◽  
Megumi Mizokoshi ◽  
Akiko Endo ◽  
Yasuyuki Tanaka
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Oxidative Degradation ◽  
Low Molecular Weight ◽  
Rubber Latex ◽  
High Ammonia ◽  
Novel Method ◽  
Η Value ◽  
Telechelic Polymer

Abstract Low molecular-weight natural rubber (LNR) and LNR latex was prepared by oxidative degradation of de-proteinized natural rubber (DPNR) latex in the presence of 1 phr of K2S2O8 and 15 phr of propanal, by shaking at 60 °C. The intrinsic viscosity [η] of DPNR with only K2S2O8 decreased from 7.2 to 5.5 after 2 h and then increased to 6.5 after 3 h. By the addition of propanal, DPNR showed a significant decrease in the [η] value of LNR with [η] of about 0.5 after 5 h of the reaction, while rubber from high-ammonia natural rubber (HANR) latex showed a slight decrease in [η]. The concentration of latex and the kind of surfactant used for stabilizing the latex had little effect on the degradation rate of DPNR latex. The LNR latex is stable as the latex form and the dried rubber coagulated from latex is transparent and colorless. The LNR was a telechelic polymer containing aldehyde and ketone groups at both terminals as determined by NMR and molecular weight analyses.

Analysis of low molecular weight compounds by MALDI-FTICR-MS

2011 ◽  
Vol 879 (17-18) ◽  
pp. 1166-1179 ◽  
Author(s):  
Hao-Yang Wang ◽  
Xu Chu ◽  
Zhi-Xiong Zhao ◽  
Xiao-Shuang He ◽  
Yin-Long Guo
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Fticr Ms ◽  
Low Molecular Weight Compounds

Degradation of wood veneers by Fenton's reagents: Effects of wood constituents and low molecular weight phenolic compounds on hydrogen peroxide decomposition and wood tensile strength loss

Holzforschung ◽  
2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Yanjun Xie ◽  
Zefang Xiao ◽  
Barry Goodell ◽  
Jody Jellison ◽  
Holger Militz ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Tensile Strength ◽  
Metal Binding ◽  
Cellulose Degradation ◽  
Iron Concentration ◽  
Wood Decay ◽  
Brown Rot ◽  
Strength Loss ◽  
Low Molecular Weight

AbstractPine wood (Pinus sylvestris) veneer strips were incubated in acetate buffer containing hydrogen peroxide and Fe ions (Fenton's reagent) to mimic aspects of brown rot decay and to assess the degradation of cellulose in wood via measurement of tensile properties (measured in a zero-span mode). Varying the type of iron (ferrous or ferric sulfate) mixed with H2O2did not yield significant differences in the rates of H2O2concentration and tensile strength reduction. However, increasing the amount of wood material (the number of wood strips) in the reaction mixture elevated Fe(III) reduction in solution, indicating that wood constituents participated in this reaction. Increasing concentrations of Fe(III) in the reaction mixture resulted in a decrease in H2O2in solution. Despite an increase in iron concentration and H2O2decomposition under these conditions, a uniform and consistent strength loss of 30% was observed at all Fe(III) concentrations tested. At fixed Fe(III) concentrations, increasing the H2O2concentration linearly increased the strength loss of the veneers up to approximately 50% within 24 h. The addition of a low molecular weight, metal-binding, phenolic compound (2,3-dihydroxybenzoic acid) and of a non-chelating hydroquinone to the reaction mixtures entailed a more rapid consumption of H2O2; however, the tensile strength loss of the veneers decreased with increasing concentration of the phenolics. Thus, in contrast to previous studies on cellulose degradation, phenolics reduced the degree of wood decay in a Fenton system.

Possible biochemical roles of oxalic acid as a low molecular weight compound involved in brown-rot and white-rot wood decays

1997 ◽  
Vol 53 (2-3) ◽  
pp. 103-113 ◽  
Author(s):  
Mikio Shimada ◽  
Yasumi Akamtsu ◽  
Toshiaki Tokimatsu ◽  
Kayoko Mii ◽  
Takefumi Hattori
Keyword(s):  
Molecular Weight ◽  
Oxalic Acid ◽  
Brown Rot ◽  
White Rot ◽  
Low Molecular Weight
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