Yoon Soo Kim

• Professor Emeritus at Chonnam National University

This review focuses on the pivotal role microscopy has played in diagnosing the type(s) of microbial attacks present in waterlogged ancient wooden objects, and to understand the nature and extent of deterioration of such objects. The microscopic journey began with the application of light microscopy (LM) to examine the deterioration of waterlogged...

While numerous studies have examined microbial attacks on waterlogged archaeological wood, limited information is available regarding microbial attacks in waterlogged tropical hardwoods submerged in marine environments. In this context, we explored microbial attacks in waterlogged archaeological rosewood (Dalbergia species), a tropical hardwood spe...

Bacterial decay in compression wood (CW) tracheids of waterlogged archaeological wood (WAW) was investigated using light microscopy, confocal laser scanning microscopy, transmission electron microscopy (TEM), and TEM immunogold labeling. Erosion bacteria were identified as the main degraders, and the extent of cell wall degradation differed dependi...

This review provides information on the advances made leading to an understanding of the micromorphological patterns produced during microbial degradation of lignified cell walls of buried and waterlogged archaeological woods. This knowledge not only serves as an important diagnostic signature for identifying the type(s) of microbial attacks presen...

The bacterial decay of waterlogged archeological wood (WAW, hard pine spp.) taken from Daebudo shipwreck No. 2, which was buried in the intertidal zone in the mid-west coast (Yellow sea) of South Korea approximately 800 years ago, was investigated. The maximum moisture content of the outer parts (approx. 3 cm of depth) of WAW was approximately 4.2...

Besides traditional applications wood is being increasingly used as replacement for fossil-based products. Due to its storage capacity for CO2, wood will also greatly contribute to a reduction of greenhouse gases in the atmosphere. Therefore wood experiences new attractiveness as a highly valuable and environmentally friendly natural resource. Apar...

This review presents information on the relationship of ultrastructure and composition of wood cell walls, in order to understand how wood degrading bacteria utilise cell wall components for their nutrition. A brief outline of the structure and composition of plant cell walls and the degradation patterns associated with bacterial degradation of woo...

This review presents information on the relationship of ultrastructure and composition of wood cell walls, in order to understand how wood degrading bacteria utilise cell wall components for their nutrition. A brief outline of the structure and composition of plant cell walls and the degradation patterns associated with bacterial degradation of woo...

Wood cell wall ultrastructure, particularly lignin concentration, has an effect on bacterial degradation of cell wall.

Sole pretreatment methods always have limitations in improving enzymatic hydrolysis of wood due to the multi-scale biomass recalcitrance. Herein, dilute acid pretreatment (DAP) with 2% hydrochloric acid at 160 °C and mild ionic liquid pretreatment (MILP) with 1-ethyl-3-methylimidazolium acetate at 90 °C were combined to increase cellulose accessibi...

A comprehensive understanding of the structural and chemical nature of plant cell walls is important from both the perspectives of plant biotechnology and of commercial utilization. The Raman imaging technique is a preferred solution for its ability to offer spatial and spectral information simultaneously. However, the exact spectra of hemicellulos...

Soft rot decay is characterized by the chains of bi-conical and cylindrical cavities pro- duced by Ascomycetes and Fungi Imperfecti within secondary cell walls that are aligned parallel to cellulose microfibrils. Although the term “soft rot” was first used by Savory (1954), Blanchette (1990) reported that several investigators had described these c...

The spectral contaminants are inevitable during micro-Raman measurements. A key challenge is how to remove them from the original imaging data, since they can distort further results of data analysis. Here, we propose a method named “automatic pre-processing method for Raman imaging data set (APRI)”, which includes the adaptive iteratively reweight...

Wood-degrading bacteria (WDB) are ubiquitous in nature and are present in terrestrial and aquatic environments. WDB have evolved mechanisms and adaptations that enable them to effectively utilize lignocellulosic materials without entering in direct competition with the basidiomycete white and brown-rot fungi, which can degrade wood more rapidly. WD...

Wood cultural heritage (WCH) as tangible objects can be classified into three groups: (1) moveable, (2) immoveable, and (3) underwater. WCH are in a constant state of physical and chemical transformation and can deteriorate over time. The extent of deterioration of WCH can vary with agents of deterioration, wood species, and environmental condition...

The 1–3-year-old bamboo (Phyllostachys puberscence) culms were exposed to ambient weathering conditions for 12 months. Changes in color, surface topography, and chemical features of bamboo culms by weathering were investigated. Changes in the surface color of culms increased sharply in the first 3 months weathering and then slowly decreased compare...

Secondary Xylem Biology: Origins, Functions, and Applications provides readers with many lenses from which to understand the whole scope and breadth of secondary xylem. The book builds on a basic comprehension of xylem structure and development before delving into other important issues such as fungal and bacterial degradation and biofuel conversio...

Studies on the compression wood in tropical gymnosperms are uncommon due to their limited distribution and over-exploitation. Microscopic examination of the heartwood of two tropical gymnosperms, Agathis borneensis (local name: bindang, damar minyak) and Dacrydium elatum (local name: sempilor) growing on higher elevations in Sarawak, Malaysia showe...

Main conclusion: Hydrothermal pretreatment initially removed the lignin-free xylan from the middle layer of secondary wall, followed by the lignin-bound xylan, but the cellulose-bound xylan was seldom removed by this pretreatment. An in-depth understanding of the mechanism of xylan removal during hydrothermal pretreatment (HTP) of wood is critical...

The presence of fibrillar structures (FS) in the cell corner middle lamella (CCML) regions was demonstrated in several species of plants. The FS in the CCML of bass wood, oak wood, and bamboo became clearly visible after removal of lignin by wood decay fungi. The occurrence of FS in the CCML was also confirmed by examining early stages of cell wall...

Sequential changes occurring in cell walls during expansion, secondary wall (SW) deposition and lignification have been studied in the differentiating xylem elements of Holoptelea integrifolia using transmission electron microscopy. The PATAg staining revealed that loosening of the cell wall starts at the cell corner middle lamella (CCML) and sprea...

There is little information about the ultrastructural changes taking place in the radial walls of fusiform cambial cells during differentiation into xylem derivatives. The present study reports the early events occurring in the radial walls of fusiform cambial cells (FCCs) during fiber elongation in Holoptelea integrifolia, a deciduous tropical tre...

Ten light-harvesting complex (Lhc) proteins were investigated to determine which was the most appropriate protein marker of senescence in detached rice leaves. The levels of Lhc proteins were monitored by immunoblot analysis, which was conducted using commercially available antibodies raised against each Lhc protein. Among the Lhc proteins evaluate...

By using a functional magnetic resonance imaging (fMRI) technique we assessed brain activation patterns while subjects were viewing the living environments representing natural and urban scenery. A total of 28 healthy right-handed subjects underwent an fMRI on a 3.0 Tesla MRI scanner. The stimulation paradigm consisted of three times the rest condi...

Long-term field trials of wood in ground contact give valuable data on the natural durability of the material. The European Standard EN 350 gives guidance on how to perform these durability classification, but is limited to the use of averages of in-service life of a set of specimens compared to a reference set. Starting from a database of visual a...

Little is known about the decay pattern of bamboo by wood decay fungi, and the information available on fungal degradation of wood from other plant taxa cannot form the basis for understanding wood decay in bamboo because of differences in lignin composition and distribution. The present work was undertaken to elucidate the degradation pattern of b...

The purpose of this study was to produce recombinant xylanase in transgenic plants and to test its potential application for pulp bleaching. The xynII xylanase gene from Trichoderma reesei was inserted into the Arabidopsis genome. Many transgenic plants produced biologically active XYNII and accumulated in leaves at level of 1.4-3.2% of total solub...

The decay pattern in bamboo fibers caused by a brown rot fungus, Gloeophyllum trabeum, was examined by microscopy. The inner part of the polylaminate secondary wall was degraded, while the outer part of the secondary wall remained essentially intact. Degradation in bamboo fiber walls without direct contact with the fungal hyphae was similar to wood...

Seasonal cambial activity and xylem anatomy were studied in Prosopis spicigera Linn. (Mimosaceae) growing under the influence of combined air pollutants. Cambial cell division and differentiation of secondary xy-lem began in April, reached a peak in July–August and ceased in October in trees (normal) growing in a relatively unpolluted locality. In...

The effect of a short-term low temperature on cellular characteristics of a frost ring in radiata pine (Pinus radiata) secondary xylem was investigated using various microscopic techniques. Cell walls in the frost ring, that formed in the earlywood due to an abrupt drop in the temperature one night in the Spring, were poorly developed, lacking in t...

Conifer needles exposed to ambient air pollutants were observed by a scanning electron microscope (SEM). Predominant changes on needles were the breakdown and the aggregation of wax structures on stomatal chambers. However, the mode of destruction in stomatal wax structures was dependent on the pollutants. Ginkgo biloba seemed to be resistant to ai...

This review discusses the morphological changes and biological responses of plants irradiated with gamma rays. Seedlings exposed to relatively low doses of gamma rays (1-5 Gy) developed normally, while the growth of plants irradiated with a high dose gamma ray (50 Gy) was significantly inhibited. Based on TEM observations, chloroplasts were extreme...

Peroxidases (PODs) were localized in pumpkin tissues by using an immunogold labeling technique in combination with transmission electron microcopy (TEM). Polyclonal antibodies raised in rabbits against horseradish peroxidase were utilized. The localization patterns of gold particles for peroxidases from tissues of both control and gamma-irradiated...

The heartwood of cengal (Neobalanocarpus heimii) is known to have a high degree of decay resistance by virtue of its high extractive content. After 30 years in ground contact an utility pole of this tropical hardwood was found to be degraded only in the surface layers by cavity-forming soft rot fungi. The present work was undertaken I) to character...

Information on the micro-distribution of lignin within the middle lamella is only just beginning to emerge. This paper provides evidence of marked heterogeneity in the micro-distribution of lignin, pectin, peroxidase and hydrogen peroxide in the middle lamella of alfalfa (Medicago sativa). Specimens from alfalfa stems were collected and processed f...

Rice husks were subjected to dry-grinding and steam-explosion to reduce their sizes. Subsequently, the surface of rice husk particles was modified using two different coupling agents, maleated polypropylene (MAPP) and γ-aminopropyltriethoxysilane (γ-APS, A-1100) to induce chemical reactions between the husk surface and the coupling agents used. The...

Microscopic examination showed the cell wall decay pattern produced by the brown-rot fungus Coniophora puteana to be different from the degradation pattern known to be typical for brown-rot fungi. Erosion and thinning of cell walls in patterns considered to be characteristic of white-rot decay were observed. In particular, the fungal strain COP 202...

Hydrolysis of cellulose requires two different types of cellulases: exo- and endocellulase. Here, we investigated for the hydrolysis of cellulose by two types of cellulases, an endoglucanase (Cel5) from Ruminococcus albus fused with the xylanase A cellulose binding domain II (CBM6) of Clostridium stercorarium and Thermobifidus fusca E3, an exogluca...

The Bremen Cog is a big ship built AD 1380 from oak wood. After its recovery from the river Weser, the waterlogged ships timbers were successfully stabilized using a novel twostep polyethylene glycol (PEG) treatment. An electron microscopic study of the patterns of degradation and of the distribution of PEG within the Cog wood is described. Descrip...

Agrobacterium-mediated gene transformation was used to introduce plastidic protoporphyrinogen IX oxidase (Protox) genes from Arabidopsis, with and without the transit sequence, into the rice genome. They were placed under the control of the constitutive and ubiquitous maize ubiquitin promoter, and their abilities to confer resistance to the dipheny...

We developed a method involving air-drying of a rubber suspension after fixation in glutaraldehyde-tannic acid and postfixation in osmium tetroxide for SEM observation. For TEM immunolabeling the suspension was air-dried after osmium-only fixation. Whereas conventional methods failed to satisfactorily stabilize rubber particles, the methods describ...

Rice husk is a by-product of rice milling process, and a great resource as a raw biomass material for manufacturing value-added composite products. One of the potential applications is to use rice husk as filler for manufacturing lignocellulosic fiber–thermoplastic composites. This study was conducted to examine the silica distribution in rice husk...

This study was conducted to investigate the effects of reaction pH condition and hardener type on the reactivity, chemical structure, and molecular mobility of urea–formaldehyde (UF) resins. Three different reaction pH conditions, such as alkaline (7.5), weak acid (4.5), and strong acid (1.0), were used to synthesize UF resins, which were cured by...

Rubber biosynthesis takes place on the surface of rubber particles. These particles are surrounded by a monolayer membrane in which the rubber transferase is anchored. In order to gain better insight into whether rubber particles from different plant species share common structural characteristics, the micromorphology of rubber particles from Ficus...

A study was conducted on the surface features of rubberwood high temperature thermomechanical (HTMP) fibers. The transmission electron microscopy (TEM) was used for the characterization of the surface features. The fracture behavior of the cell walls of the fibers were also studied. It was found that the outer surface of the HTMP fiber wall was com...

The micromorphological evidence of degradation of middle lamella in waterlogged archaeological wood was studied. The main reason for the survival of archaeological woods after their prolonged burial in waterlogged environments is that the microbial activity is very slow under these conditions. The results indicate that degradation of the middle lam...

A study of electron microscopic evidence for the presence of a distinct S3 layer in mild compression wood tracheids of Pinus radiata was performed. S3 layers have an important role to play in strengthening the xylem tissues in standing trees and in minimizing collapse in wood tissues. These layers are also likely to be an important factor in wood p...

Examination of root tips from cucumber (Cucumis sativus L.) seedlings grown at 8 °C for varying periods ranging from 15 min to 96 h, showed marked changes in the ultrastructure of cortical cells within only 15 min of exposure. Greater parts of the cortex were affected with longer periods of exposure, but the sequence of morphological changes in cel...

Differential scanning calorimetry (DSC) was used to investigate the influence of resin synthesis parameters on the thermal behavior of low molecular weight phenol–formaldehyde (PF) resol resins prepared with different formaldehyde/phenol (F/P) molar ratios, different sodium hydroxide/phenol (NaOH/P) molar ratios, and different catalysts. As the F/P...

Peroxidases were localized in differentiating xylem cells of Populus spp. by means of immunogold labelling in combination with transmission electron microscopy (TEM). Polyclonal antibodies raised in rabbits against horseradish peroxidase were used for these experiments. Within the cytoplasm, TEM revealed a distinct labelling of the dictyosomes, ind...

It is not definitively known whether or not the production of extracellular hydrogen peroxide (H2O2) is a universal characteristic of brown-rot fungi. Cytochemical localization of H2O2 was tested in two brown-rot fungi, Tyromyces palustris and Coniophora puteana, by staining with cerium chloride, Transmission electron microscopy (TEM) showed the de...

The ultrastructure of cell walls and the mechanisms of cell wall formation are still not fully understood. The objective of our study was therefore to obtain additional fine structural details on the deposition of cell wall components during the differentiation of xylem cells in hybrid aspen (Populus tremula L. ×P. tremuloides Michx.) we used as a...

Transmission electron microscopy of Terminalia archaeological wood from an ancient Polynesian canoe showed vestures to be intact despite extensive degradation of the secondary wall by erosion bacteria. The vesture wall consisted of a lining wall resistant to degradation and an underlying wall which was partly degraded. These observations provide ev...

This study was conducted to investigate the effects of reaction pH conditions and hardener types on the reactivity, chemical structure and adhesion performance of UF resins. Three different reaction pH conditions, such as traditional alkaline-acid (7.5 4.5), weak acid (4.5), and strong acid (1.0), were used to synthesize UF resins which were cured...

This study provides electron microscopic evidence for the presence of cellulosome-like structures on the cell surface of Ruminococcus albus F-40. Electron microscopy showed that clusters of tightly packed spherical particles were located on the cell surface of R. albus. The protuberant structures present mainly on the bacterial surface and also bou...