scholarly journals Correlation between bacterial decay and chemical changes in waterlogged archaeological wood analysed by light microscopy and Py-GC/MS

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nanna Bjerregaard Pedersen ◽  
Jeannette Jacqueline Łucejko ◽  
Francesca Modugno ◽  
Charlotte Björdal
Keyword(s):  
Cell Wall ◽  
Light Microscopy ◽  
Gas Chromatography Mass Spectrometry ◽  
Wall Structure ◽  
Chemical Changes ◽  
Residual Structure ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood ◽  
Bacterial Decay

AbstractErosion bacteria are the main degraders of archaeological wood excavated from waterlogged environments. Light microscopy and analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) were exploited to study waterlogged archaeological wood (Pinus sylvestris L.) at different stages of bacterial decay. The research explored the biochemical changes related to erosion bacteria degradation of the secondary cell wall in the wood cells and the chemical changes related to abiotic processes induced by the long-term waterlogged burial environment. Erosion bacteria were demonstrated by chemical analysis to cause significant holocellulose depletion. Detailed analysis of the holocellulose and lignin pyrolysis products revealed only minor chemical changes in the residual structure even after heavy erosion bacteria decay. Chemical changes in the lignin polymer is associated to enzymatic unlocking of the lignocellulose to gain access to the holocellulose fraction of the cell wall. Chemical changes in the holocellulose fraction are suggested to stem from depolymerisation and from alterations in the polymer matrix of the residual wood cell wall structure. Interestingly, a difference was observed between the sound reference wood and the waterlogged archaeological wood without erosion bacteria decay, indicating that long-term exposure in waterlogged environments results in partial decay of the holocellulose even in absence of bacterial activity.

scholarly journals Even Visually Intact Cell Walls in Waterlogged Archaeological Wood Are Chemically Deteriorated and Mechanically Fragile: A Case of a 170 Year-Old Shipwreck

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1113 ◽  
Author(s):  
Liuyang Han ◽  
Xingling Tian ◽  
Tobias Keplinger ◽  
Haibin Zhou ◽  
Ren Li ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Intact Cell ◽  
Nitrogen Adsorption ◽  
Wet Chemistry ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood ◽  
X Ray Scattering ◽  
Crystallite Structure ◽  
Cell Wall Mechanics

Structural and chemical deterioration and its impact on cell wall mechanics were investigated for visually intact cell walls (VICWs) in waterlogged archaeological wood (WAW). Cell wall mechanical properties were examined by nanoindentation without prior embedding. WAW showed more than 25% decrease of both hardness and elastic modulus. Changes of cell wall composition, cellulose crystallite structure and porosity were investigated by ATR-FTIR imaging, Raman imaging, wet chemistry, 13C-solid state NMR, pyrolysis-GC/MS, wide angle X-ray scattering, and N2 nitrogen adsorption. VICWs in WAW possessed a cleavage of carboxyl in side chains of xylan, a serious loss of polysaccharides, and a partial breakage of β-O-4 interlinks in lignin. This was accompanied by a higher amount of mesopores in cell walls. Even VICWs in WAW were severely deteriorated at the nanoscale with impact on mechanics, which has strong implications for the conservation of archaeological shipwrecks.

scholarly journals Interactions between Different Organosilicons and Archaeological Waterlogged Wood Evaluated by Infrared Spectroscopy

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 268
Author(s):  
Carmen-Mihaela Popescu ◽  
Magdalena Broda
Keyword(s):  
Cell Wall ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Chemical Modification ◽  
Fourier Transform Infrared Spectroscopy ◽  
Fourier Transform Infrared ◽  
Organosilicon Compounds ◽  
Structural Characterisation ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood

The goal of the study was to characterise chemical interactions between waterlogged archaeological wood and organosilicon compounds applied for its conservation to shed lights on the mechanism of wood dimensional stabilisation by the chemicals. Two alkoxysilanes (methyltrimethoxysilane and (3-mercaptopropyl) trimethoxysilane) and a siloxane (1,3-bis(diethylamino)-3-propoxypropanol)-1,1,3,3-tetramethyldisiloxane) were selected for the research since they already have been proven to effectively stabilise waterlogged wood upon drying. Fourier transform infrared spectroscopy was used for structural characterisation of the degraded wood and evaluation of reactivity of the applied chemicals with polymers in the wooden cell wall. The results obtained clearly show much stronger interactions in the case of alkoxysilanes than the siloxane, suggesting a different mechanism of wood stabilisation by these compounds. The results of this study together with other data obtained in our previous research on stabilisation of waterlogged archaeological wood with organosilicon compounds allow the conclusion that the mechanism of waterlogged wood stabilisation by the used alkoxysilanes is based on bulking the cell wall by silane molecules and wood chemical modification, while in the case of the applied siloxane, it builds upon filling the cell lumina.

scholarly journals The effect of the drying method on the cell wall structure and sorption properties of waterlogged archaeological wood

2021 ◽  
Author(s):  
Magdalena Broda ◽  
Simon F. Curling ◽  
Marcin Frankowski
Keyword(s):  
Cell Wall ◽  
Supercritical Drying ◽  
Wood Properties ◽  
Storage Conditions ◽  
Cell Wall Structure ◽  
Sorption Properties ◽  
Wall Structure ◽  
Drying Methods ◽  
Drying Method ◽  
Archaeological Wood

AbstractDrying is a process affecting various wood properties, including its structure, moisture behaviour and mechanical properties. Since waterlogged wooden artefacts usually constitute priceless objects of cultural heritage, understanding the effect of drying on the complex interactions between the wood ultrastructure and the resulting properties is necessary to ensure their proper conservation. Hence, this was the aim of the present study, with a particular emphasis on the influence of drying conditions on the relations between the cell wall structure, dimensional stability and hygroscopicity of degraded archaeological wood. The choice of the particular drying methods was dictated by their final effect on wood appearance (dimensions). The results obtained clearly show that depending on the drying method applied, the resulting material differs significantly in structure, dimensions and sorption properties, despite the same degree of wood degradation. Air- and oven-drying resulted in the highest wood shrinkage, lower porosity, and a decreased number of free hydroxyls in the wood cell wall. The best wood dimensional stabilisation and the highest porosity were ensured by freeze- and supercritical drying. No correlations were found between wood structure and moisture behaviour. The outcome of the research may be useful for conservators who plan to provide the artefacts with proper storage conditions and effective conservation/reconservation.

scholarly journals Changes in the Proteome of Medicago sativa Leaves in Response to Long-Term Cadmium Exposure Using a Cell-Wall Targeted Approach

2018 ◽  
Vol 19 (9) ◽  
pp. 2498 ◽  
Author(s):  
Annelie Gutsch ◽  
Salha Zouaghi ◽  
Jenny Renaut ◽  
Ann Cuypers ◽  
Jean-Francois Hausman ◽  
...  
Keyword(s):  
Cell Wall ◽  
Medicago Sativa ◽  
Protein Identification ◽  
Molecular Mechanisms ◽  
Time Of Flight ◽  
Cell Wall Protein ◽  
Wall Structure ◽  
Cd Exposure ◽  
Targeted Approach

Accumulation of cadmium (Cd) shows a serious problem for the environment and poses a threat to plants. Plants employing various cellular and molecular mechanisms to limit Cd toxicity and alterations of the cell wall structure were observed upon Cd exposure. This study focuses on changes in the cell wall protein-enriched subproteome of alfalfa (Medicago sativa) leaves during long-term Cd exposure. Plants grew on Cd-contaminated soil (10 mg/kg dry weight (DW)) for an entire season. A targeted approach was used to sequentially extract cell wall protein-enriched fractions from the leaves and quantitative analyses were conducted with two-dimensional difference gel electrophoresis (2D DIGE) followed by protein identification with matrix-assisted laser desorption/ionization (MALDI) time-of-flight/time of flight (TOF/TOF) mass spectrometry. In 212 spots that showed a significant change in intensity upon Cd exposure a single protein was identified. Of these, 163 proteins are predicted to be secreted and involved in various physiological processes. Proteins of other subcellular localization were mainly chloroplastic and decreased in response to Cd, which confirms the Cd-induced disturbance of the photosynthesis. The observed changes indicate an active defence response against a Cd-induced oxidative burst and a restructuring of the cell wall, which is, however, different to what is observed in M. sativa stems and will be discussed.

scholarly journals Functional Genomic and Biochemical Analysis Reveals Pleiotropic Effect of Congo Red on Aspergillus fumigatus

mBio ◽  
2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Zhonghua Liu ◽  
Shriya Raj ◽  
Norman van Rhijn ◽  
Marcin Fraczek ◽  
Jean-Philippe Michel ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspergillus Fumigatus ◽  
Congo Red ◽  
Specific Binding ◽  
Cell Membrane Permeability ◽  
Growth Effect ◽  
Wall Structure ◽  
Cell Wall Polysaccharide ◽  
Resistant Mutants

ABSTRACT Inhibition of fungal growth by Congo red (CR) has been putatively associated with specific binding to β-1,3-glucans, which blocks cell wall polysaccharide synthesis. In this study, we searched for transcription factors (TFs) that regulate the response to CR and interrogated their regulon. During the investigation of the susceptibility to CR of the TF mutant library, several CR-resistant and -hypersensitive mutants were discovered and further studied. Abnormal distorted swollen conidia called Quasimodo cells were seen in the presence of CR. Quasimodo cells in the resistant mutants were larger than the ones in the sensitive and parental strains; consequently, the conidia of the resistant mutants absorbed more CR than the germinating conidia of the sensitive or parental strains. Accordingly, this higher absorption rate by Quasimodo cells resulted in the removal of CR from the culture medium, allowing a subset of conidia to germinate and grow. In contrast, all resting conidia of the sensitive mutants and the parental strain were killed. This result indicated that the heterogeneity of the conidial population is essential to promote the survival of Aspergillus fumigatus in the presence of CR. Moreover, amorphous surface cell wall polysaccharides such as galactosaminogalactan control the influx of CR inside the cells and, accordingly, resistance to the drug. Finally, long-term incubation with CR led to the discovery of a new CR-induced growth effect, called drug-induced growth stimulation (DIGS), since the growth of one of them could be stimulated after recovery from CR stress. IMPORTANCE The compound Congo red (CR) has been historically used for coloring treatment and histological examination as well to inhibit the growth of yeast and filamentous fungi. It has been thought that CR binds to β-1,3-glucans in the fungal cell wall, disrupting the organization of the cell wall structure. However, other processes have been implicated in affecting CR sensitivity. Here, we explore CR susceptibility through screening a library of genetic null mutants. We find several previously uncharacterized genetic regulators important for CR susceptibility. Through biochemical and molecular characterization, we find cell membrane permeability to be important. Additionally, we characterize a novel cell type, Quasimodo cells, that occurs upon CR exposure. These cells take up CR, allowing the growth of the remaining fungi. Finally, we find that priming with CR can enhance long-term growth in one mutant.

scholarly journals Long-term cadmium exposure influences the abundance of proteins that impact the cell wall structure in Medicago sativa stems

Plant Biology ◽  
2018 ◽  
Vol 20 (6) ◽  
pp. 1023-1035 ◽  
Author(s):  
A. Gutsch ◽  
E. Keunen ◽  
G. Guerriero ◽  
J. Renaut ◽  
A. Cuypers ◽  
...  
Keyword(s):  
Cell Wall ◽  
Medicago Sativa ◽  
Cadmium Exposure ◽  
Cell Wall Structure ◽  
Wall Structure

Chemical changes in cell wall structure of five strains ofParacoccidioides brasiliensis

1984 ◽  
Vol 22 (3) ◽  
pp. 255-257 ◽  
Author(s):  
Gioconda San-Blas ◽  
Felipe San-Blas ◽  
Domitila Ordaz ◽  
Sonia Centeno ◽  
María Cecilia Albornoz
Keyword(s):  
Cell Wall ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Chemical Changes

Waterlogged archaeological wood—chemical changes by conservation and degradation

2006 ◽  
Vol 37 (10) ◽  
pp. 1171-1178 ◽  
Author(s):  
M. Christensen ◽  
M. Frosch ◽  
P. Jensen ◽  
U. Schnell ◽  
Y. Shashoua ◽  
...  
Keyword(s):  
Chemical Changes ◽  
Archaeological Wood ◽  
Waterlogged Archaeological Wood

Bacterial Peptidoglycan Stapling with Functionalized D-Amino Acids

2019 ◽  
Author(s):  
Sylvia L. Rivera ◽  
Akbar Espaillat ◽  
Arjun K. Aditham ◽  
Peyton Shieh ◽  
Chris Muriel-Mundo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Clinical Success ◽  
Bacterial Species ◽  
Enzymatic Reaction ◽  
Amino Acid Derivative ◽  
Wall Structure ◽  
Live Bacteria ◽  
Cross Links ◽  
Osmotic Lysis ◽  
Bacterial Peptidoglycan

Transpeptidation reinforces the structure of cell wall peptidoglycan, an extracellular heteropolymer that protects bacteria from osmotic lysis. The clinical success of transpeptidase-inhibiting β-lactam antibiotics illustrates the essentiality of these cross-linkages for cell wall integrity, but the presence of multiple, seemingly redundant transpeptidases in many bacterial species makes it challenging to determine cross-link function precisely. Here we present a technique to covalently link peptide strands by chemical rather than enzymatic reaction. We employ bio-compatible click chemistry to induce triazole formation between azido- and alkynyl-D-alanine residues that are metabolically installed in the cell walls of Gram-positive and Gram-negative bacteria. Synthetic triazole cross-links can be visualized by substituting azido-D-alanine with azidocoumarin-D-alanine, an amino acid derivative that undergoes fluorescent enhancement upon reaction with terminal alkynes. Cell wall stapling protects the model bacterium Escherichia coli from β-lactam treatment. Chemical control of cell wall structure in live bacteria can provide functional insights that are orthogonal to those obtained by genetics.<br>

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