6 results
Search Results
2. Fungal pigments on paper: Raman and quantum chemistry studies of Alternaria Sp.
- Author
-
Volkov, Victor V. and Perry, Carole C.
- Subjects
- *
QUANTUM chemistry , *ALTERNARIA , *OPTICAL computing , *PIGMENTS , *MOLECULAR biology , *FUNGAL metabolites - Abstract
To advance our understanding of the molecular biochemistry of fungi which impact cultural heritage in libraries, museums and archives we investigated the diagnostic capacity of Raman spectroscopy to identify the composition of colored chromophores of fungi on paper. In this study we explored the diagnostic capacity of resonant Raman to distinguish chromophores in fungal filaments stimulated to grow on paper under high humidity with a focus on characterizing chromophores of Alternaria group species. To facilitate molecular analysis, we conducted quantum chemistry calculations of representative metabolites having optical absorption in the ultraviolet–visible spectral range. Comparing theory and experiment we show that fonsecin, erythroglaucin and aurasperone type chromophores occur in mature hyphal filaments with β-carotene dominant in yeast depositions on paper surfaces. Resonant Raman of mature filaments suggests a further contribution of carotenes longer than β-carotene to the spectral signature. Using microscopic resolution, we distinguish rich sets of Raman signatures that we assign to lignin, flavoglaucin, riboflavin, cycloleucomelon(e) and asperyellone molecular components in the spatial regions where filaments initiate from yeast depositions. In such regions, where filament microstructures stimulate development of a mature three-dimensional scaffold, the diversity of Raman resonances confirms a rich biochemistry of the developing structures. The library of computed optical and spectroscopic responses of characteristic fungal chromophores and metabolites presented here is essential for understanding the effect of fungi on a wide range of objects made from paper including books, prints, drawings, watercolors, engravings and even sculptures as well as designing next generation materials based on fungal hyphal mats. • Non-invasive Raman spectroscopy can be used to identify pigments in fungi. • Quantum chemistry (DFT) combined with Raman for quantitative measure of chromophores. • Computed optical responses of fungal chromophores and metabolites. • Raman spectroscopy combined with Quantum chemistry as tools for cultural heritage. • Alternaria sp. generates specific pigments when grown on paper. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Mycological and FTIR analysis of biotic foxing on paper substrates
- Author
-
Zotti, M., Ferroni, A., and Calvini, P.
- Subjects
- *
DISCOLORATION , *FOURIER transform infrared spectroscopy , *PAPER , *MICROFUNGI , *MICROSCOPY , *ULTRAVIOLET radiation , *X-ray diffraction , *ORGANIC compounds , *BIODEGRADATION - Abstract
Abstract: The small rusty stains (foxing) frequently found on historic paper documents, books, and prints have generally been analysed in the past by optical microscope through their morphochromatic appearance under visible light and UV radiation. Despite increased research efforts with more sophisticated techniques (mainly SEM and XRF), the biotic or even chemical origin of these stains remains unclear. The purpose of this paper is to verify to what extent a simple technique such as FTIR-ATR spectroscopy can be utilised for a clearer understanding of the controversial nature of foxing. Since this technique is sensitive to several organic chemical groups that are in common with both fungi and gelatine-sized ancient paper, some modern cardboards stained by biotic foxing have been selected for the analyses. The results clearly show the importance of FTIR and mycological analyses for the identification of residual microfungal agents, together with the by-products of their activity on paper substrates. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
4. Multiphoton microscopy: a personal historical review, with some future predictions
- Author
-
Colin J. R. Sheppard
- Subjects
Paper ,two-photon fluorescence ,Microscope ,Materials science ,Biomedical Engineering ,Nanotechnology ,History, 21st Century ,01 natural sciences ,Multiphoton Fluorescence Microscopy ,law.invention ,010309 optics ,Biomaterials ,Special Section Celebrating Thirty Years of Multiphoton Microscopy in the Biomedical Sciences ,Signal strength ,law ,Confocal microscopy ,0103 physical sciences ,Microscopy ,Humans ,focal modulation microscopy ,image scanning microscopy ,fungi ,Pulse duration ,Second-harmonic generation ,History, 20th Century ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Microscopy, Fluorescence, Multiphoton ,Multiphoton fluorescence microscope ,Microscopy, Fluorescence ,multiphoton microscopy ,Forecasting ,second-harmonic generation - Abstract
The historical development of multiphoton microscopy is described, starting with a review of two-photon absorption, and including two- and three-photon fluorescence microscopies, and second- and third-harmonic generation microscopies. The effects of pulse length on signal strength and breakdown are considered. Different contrast mechanisms, including use of nanoparticles, are discussed. Two new promising techniques that can be applied to multiphoton microscopy are described.
- Published
- 2020
5. Effect of Cellulases and Xylanases on Refining Process and Kraft Pulp Properties
- Author
-
Kamila Przybysz Buzała, Halina Kalinowska, Małgorzata Derkowska, and Piotr Przybysz
- Subjects
0106 biological sciences ,lcsh:Medicine ,02 engineering and technology ,Biochemistry ,01 natural sciences ,chemistry.chemical_compound ,Filter Paper ,Cellulases ,Electron Microscopy ,lcsh:Science ,Microscopy ,Multidisciplinary ,biology ,Organic Compounds ,Hydrolysis ,Pulp (paper) ,021001 nanoscience & nanotechnology ,Pulp and paper industry ,Enzyme structure ,Enzymes ,Laboratory Equipment ,Chemistry ,Xylosidases ,Aspergillus ,Kraft process ,Physical Sciences ,Xylanase ,Engineering and Technology ,Scanning Electron Microscopy ,Alternative Energy ,Cellular Structures and Organelles ,0210 nano-technology ,Kraft paper ,Research Article ,Paper ,Equipment ,Cellulase ,engineering.material ,Research and Analysis Methods ,010608 biotechnology ,Cellulose ,Filter paper ,business.industry ,Organic Chemistry ,lcsh:R ,Organisms ,Fungi ,Chemical Compounds ,Biology and Life Sciences ,Proteins ,Cell Biology ,Pinus ,Molds (Fungi) ,Biotechnology ,Energy and Power ,chemistry ,Enzyme Structure ,Enzymology ,engineering ,biology.protein ,lcsh:Q ,business - Abstract
Samples of bleached kraft pine cellulosic pulp, either treated with an enzyme preparation (a Thermomyces lanuginosus xylanase, an Aspergillus sp. cellulase, and a multienzyme preparation NS-22086 containing both these activities) or untreated, were refined in a laboratory PFI mill. The treatment with cellulases contained in the last two preparations significantly improved the pulp’s susceptibility to refining (the target freeness value of 30°SR was achieved in a significantly shorter time), increased water retention value (WRV) and fines contents while the weighted average fiber length was significantly reduced. These changes of pulp parameters caused deterioration of paper strength properties. The treatment with the xylanase, which partially hydrolyzed xylan, small amounts of which are associated with cellulose fibers, only slightly loosened the structure of fibers. These subtle changes positively affected the susceptibility of the pulp to refining (refining energy was significantly reduced) and improved the static strength properties of paper. Thus, the treatment of kraft pulps with xylanases may lead to substantial savings of refining energy without negative effects on paper characteristics.
- Published
- 2016
6. [Microscopic examination of paper stained by the fungus Gymnoscus setosus]
- Author
-
Iu P, NIUKSHA
- Subjects
Paper ,Microscopy ,Fungi - Published
- 1960
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.