Lignocellulose oxidation by low molecular weight metal-binding compounds isolated from wood degrading fungi: A comparison of brown rot and white rot systems and the potential application of chelator-mediated fenton reactions* *This is paper 2519 of the Maine Agricultural and Forest Experiment Station. We thank the Wood Utilization Research program at the University of Maine for support of this work. We also appreciate the assistance of Mr. Duan Hui and Ms. Jing Bian in the laboratory.

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.

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

Journal of Biotechnology ◽

10.1016/s0168-1656(97)01679-9 ◽

1997 ◽

Vol 53 (2-3) ◽

pp. 103-113 ◽

Cited By ~ 122

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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Revalorizing Lignocellulose for the Production of Natural Pharmaceuticals and Other High Value Bioproducts

Current Medicinal Chemistry ◽

10.2174/0929867324666170912095755 ◽

2019 ◽

Vol 26 (14) ◽

pp. 2475-2484 ◽

Cited By ~ 4

Author(s):

Congqiang Zhang ◽

Heng-Phon Too

Keyword(s):

Clostridium Thermocellum ◽

White Rot Fungi ◽

Brown Rot ◽

Cost Effective ◽

White Rot ◽

Chemical Pretreatment ◽

Significant Challenge ◽

Drug Molecules ◽

Natural Medicine ◽

Renewable Natural Resource

Lignocellulose is the most abundant renewable natural resource on earth and has been successfully used for the production of biofuels. A significant challenge is to develop cost-effective, environmentally friendly and efficient processes for the conversion of lignocellulose materials into suitable substrates for biotransformation. A number of approaches have been explored to convert lignocellulose into sugars, e.g. combining chemical pretreatment and enzymatic hydrolysis. In nature, there are organisms that can transform the complex lignocellulose efficiently, such as wood-degrading fungi (brown rot and white rot fungi), bacteria (e.g. Clostridium thermocellum), arthropods (e.g. termite) and certain animals (e.g. ruminant). Here, we highlight recent case studies of the natural degraders and the mechanisms involved, providing new utilities in biotechnology. The sugars produced from such biotransformations can be used in metabolic engineering and synthetic biology for the complete biosynthesis of natural medicine. The unique opportunities in using lignocellulose directly to produce natural drug molecules with either using mushroom and/or ‘industrial workhorse’ organisms (Escherichia coli and Saccharomyces cerevisiae) will be discussed.

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Mentors' experiences in an osteopathic medical student research program

Journal of Osteopathic Medicine ◽

10.1515/jom-2020-0251 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Tyler Hamby ◽

W. Paul Bowman ◽

Don P. Wilson ◽

Riyaz Basha

Keyword(s):

Medical Students ◽

Research Program ◽

Online Survey ◽

Medical Schools ◽

Systematic Instruction ◽

Medical Student Research ◽

Research Programs ◽

Student Mentor ◽

The University

Abstract Context Medical students, especially at osteopathic medical schools, have limited research exposure. Systematic instruction in research, supervised by qualified mentors, could motivate osteopathic medical students to pursue research in their careers, thereby increasing the number of future clinician-scientists. Recruiting and retaining suitable research mentors are crucial to sustaining such programs, but this task is also particularly challenging for osteopathic medical schools. Objectives To assess mentors' experiences in a voluntary student-mentor medical research program. Methods An online survey was sent to 76 university- or hospital-based participants who previously mentored 219 medical students between 2014 and 2019. The questionnaire consisted of 13 items with responses in checklist, five-point Likert scale, and categorical multiple-choice formats, assessing motivation for participation, satisfaction with the program, and interest in future participation. Data were analyzed descriptively, and responses from mentors at the university and hospital were compared using univariate logistic and ordinal regression analyses. Results Among 70 (92.1%) mentors who responded to the survey, 61 (87.1%) reported being motivated by a desire to help medical students learn research. Forty-nine (70.0%) mentors indicated that furthering their own research productivity was a motivation, and hospital-based mentors were statistically significantly more likely to endorse this source of motivation (OR=2.02; 95% CI=1.18–3.45; p=0.01). Most respondents were satisfied with the quality of the students' work (59 [84.3%]) and with the program (59 [85.5%]). However, 46 (65.7%) suggested the program could be enhanced by requiring medical students to be physically present in the clinic or laboratory for a minimum amount of time. Importantly, most (58 [84.1%]) mentors reported that they would be interested in participating in future mentored research programs. Conclusions Mentors were motivated to participate in the voluntary research program for both altruistic and professional reasons. Since most mentors reported being satisfied with the program, it is likely they would participate in future mentored research programs. Our results suggest that mentors viewed this voluntary research program as mutually beneficial.

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A novel peroxidase from white-rot Agaricomycetes fungus Phlebia radiata strain KB-DZ15: Its purification, characterisation, and potential application for dye-decolorisation and lignin-biodegradation

Biocatalysis and Biotransformation ◽

10.1080/10242422.2021.1939315 ◽

2021 ◽

pp. 1-13

Author(s):

Khelifa Bouacem ◽

Fawzi Allala ◽

Nadia Zaraî Jaouadi ◽

Sondes Hamdi ◽

Sondes Mechri ◽

...

Keyword(s):

Potential Application ◽

White Rot ◽

Lignin Biodegradation ◽

Phlebia Radiata ◽

Dye Decolorisation

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Growth behavior of wood-destroying fungi in chemically modified wood: wood degradation and translocation of nitrogen compounds

Holzforschung ◽

10.1515/hf-2020-0252 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Lukas Emmerich ◽

Maja Bleckmann ◽

Sarah Strohbusch ◽

Christian Brischke ◽

Susanne Bollmus ◽

...

Keyword(s):

Protective Action ◽

Treated Wood ◽

Untreated Wood ◽

Brown Rot ◽

Decay Resistance ◽

White Rot ◽

Decay Fungi ◽

Chemically Modified ◽

Decay Tests ◽

Modified Wood

Abstract Chemical wood modification has been used to modify wood and improve its decay resistance. However, the mode of protective action is still not fully understood. Occasionally, outdoor products made from chemically modified timber (CMT) show internal decay while their outer shell remains intact. Hence, it was hypothesized that wood decay fungi may grow through CMT without losing their capability to degrade non-modified wood. This study aimed at developing a laboratory test set-up to investigate (1) whether decay fungi grow through CMT and (2) retain their ability to degrade non-modified wood. Acetylated and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) treated wood were used in decay tests with modified ‘mantle specimens’ and untreated ‘core dowels’. It became evident that white rot (Trametes versicolor), brown rot (Coniophora puteana) and soft rot fungi can grow through CMT without losing their ability to degrade untreated wood. Consequently, full volume impregnation of wood with the modifying agent is required to achieve complete protection of wooden products. In decay tests with DMDHEU treated specimens, significant amounts of apparently non-fixated DMDHEU were translocated from modified mantle specimens to untreated wood cores. A diffusion-driven transport of nitrogen and DMDHEU seemed to be responsible for mass translocation during decay testing.

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Research program on electric propulsion at the University of Rome

10.2514/6.1970-1086 ◽

1970 ◽

Author(s):

A. FANCHIOTTI ◽

S. FANTO ◽

V. NASO ◽

F. PIPERNO ◽

G. SIMONI ◽

...

Keyword(s):

Research Program ◽

Electric Propulsion ◽

University Of Rome ◽

The University

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Detection of fungal decay by high-energy multiple impact (HEMI) testing

Holzforschung ◽

10.1515/hf.2006.036 ◽

2006 ◽

Vol 60 (2) ◽

pp. 217-222 ◽

Cited By ~ 16

Author(s):

Christian Brischke ◽

Christian Robert Welzbacher ◽

Andreas Otto Rapp

Keyword(s):

Structural Changes ◽

Brown Rot ◽

High Energy ◽

White Rot ◽

Fungal Decay ◽

Highly Correlated ◽

Thermally Modified Wood ◽

Impact Milling ◽

Multiple Impact ◽

Steel Balls

Abstract The suitability of a previously described high-energy multiple impact (HEMI) test for the detection of early fungal decay was examined. The HEMI test characterises the treatment severity of thermally modified wood by stressing the treated material by thousands of impacts of pounding steel balls. This method differentiates between heat treatment intensities, which are manifest as structural changes in the wood. Similar changes in wood structure are known for wood decayed by fungi. Pine (Pinus sylvestris L.) decayed by brown rot and beech (Fagus sylvatica L.) decayed by white rot were tested. Mass loss caused by fungal decay and resistance to impact milling (RIM) determined in HEMI tests were found to be highly correlated. Testing of non-degraded pine, beech, and ash (Fraxinus exelsior L.) showed only marginal effects of wood density on RIM. Furthermore, annual ring angles and RIM of spruce (Picea abies Karst.) were not correlated. Accordingly, the detection of RIM reduction in decayed wood is not masked by variations in density and orientation of the annual rings. Previous results showed no adverse effects of weathering on RIM. Thus, the detection of fungal decay with HEMI tests is feasible not only for laboratory purposes, but also for wood in outdoor applications that has already undergone weathering.

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Prospective Study of White Matter Health for an Altitude Chamber Research Program

Aerospace Medicine and Human Performance ◽

10.3357/amhp.5730.2021 ◽

2021 ◽

Vol 92 (4) ◽

pp. 215-222

Author(s):

Desmond M. Connolly ◽

Henry T. Lupa

Keyword(s):

White Matter ◽

Prospective Study ◽

Research Program ◽

Past History ◽

Brain Magnetic Resonance Imaging ◽

White Matter Injury ◽

Study Entry ◽

Exposure Limits ◽

Brain White Matter ◽

The University

INTRODUCTION: Hypobaric decompression has been associated with brain white matter injury. Relevant exposure limits are unknown, raising ethical concerns over safety of volunteers for altitude chamber research. To inform this, a prospective study of white matter status using brain Magnetic Resonance Imaging (MRI) was conducted before and after a 9-mo program of hypobaric research.METHODS: Volunteers underwent 3-D, volumetric, fluid attenuated inversion recovery (FLAIR) MRI at the University of Nottingham, UK, on study entry and again after their final exposure. MRI data were analyzed and reported independently at the University of Maryland, Baltimore, MD, USA. Entry criteria were 5 subcortical white matter hyperintensities (WMH) of total volume 0.08 mL.RESULTS: One volunteer failed screening with 63 WMH (total volume 2.38 mL). Eleven individuals completed 160 short-duration (< 1h) exposures (range 3 to 26) to 18,000 ft pressure altitude (maximum 40,000 ft), no more often than twice weekly. The cohort exhibited eight total WMH on study entry (total volume 0.166 mL) and five (mostly different) total WMH on exit (0.184 mL). Just one WMH (frontal lobe) was present on both entry and exit scans. Excess background WMH on MRI screening were associated with past mild traumatic brain injury (MTBI).CONCLUSIONS: One hypoxia familiarization plus multiple, brief, infrequent, nonhypoxic hypobaric exposures (with denitrogenation) have not promoted WMH in this small cohort. Less intensive programs of decompression stress do not warrant MRI screening. A negative past history of MTBI has strong negative predictive value for excess WMH in young healthy subjects (N 33).Connolly DM, Lupa HT. Prospective study of white matter health for an altitude chamber research program. Aerosp Med Hum Perform. 2021; 92(4):215222.

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