Fabrication of a tunable photothermal actuator via in situ oxidative polymerization of polydopamine nanoparticles in hydrogel bilayers.

Photothermally triggered actuation enables the remote and local control of a material. The complex actuation can be achieved by controlling the photothermal efficiency of the material, which is crucial for the development of soft actuators. In this study, the photothermal efficiency of a hydrogel bilayer actuator consisting of a passive agarose/alginate double-network hydrogel layer and an active poly(N-isopropylacrylamide) (PNIPAm) layer was controlled via in situ oxidative polymerization of polydopamine nanoparticles (PDA NPs). Highly concentrated PDA NPs were successfully incorporated into the hydrogel bilayer without interrupting or weakening the polymer network during polymerization. The photothermal efficiency of the actuator was controlled using the number of polymerization cycles. Upon light irradiation, the heat generated by the photothermal effect of PDA NPs caused the shrinkage of the PNIPAm layer, resulting in the shape-morphing of the bilayer. The broad light absorption properties of PDA NPs allowed the bilayer to actuate under sunlight or visible light. Finally, we demonstrated controlled photothermal actuation using a pinwheel-shaped actuator consisting of four panels with different photothermal efficiencies.

Preparation and In Vitro Release Studies of Ibuprofen Loaded Nanoparticles Made from PHO and PEGMA-g-PHO.

Monoacrylate-poly(ethylene glycol) grafted poly(3-hydroxyoctanoate) (PEGMA-g-PHO) copolymer was obtained by UV irradiation and ibuprofen (IBU) loaded nanoparticles with PHO or PEGMA-g-PHO polymers were successfully prepared by a single emulsion process. Size of IBU-loaded nanoparticles was about 300 nm based on particle size measurement. Their shapes were spherical. To study drug release properties, IBU release from nanoparticles were performed with FBS buffer. Higher burst release of IBU was observed with the highest graft density of PEGMA groups and 100% drug release was found in 3, 6, and 12 days for PHO, PEGMA-g-PHO0.05, and PEGMA-g-PHO0.15, respectively. Our results suggest that hydrophobic PHO and more hydrophilic PEGMA-g-PHO could be regarded as good candidates of drug release carriers.

Identification of five novel genetic loci related to facial morphology by genome-wide association studies.

BACKGROUND: Face morphology is strongly determined by genetic factors. However, only a small number of genes related to face morphology have been identified to date. Here, we performed a two-stage genome-wide association study (GWAS) of 85 face morphological traits in 7569 Koreans (5643 in the discovery set and 1926 in the replication set). RESULTS: In this study, we analyzed 85 facial traits, including facial angles. After discovery GWAS, 128 single nucleotide polymorphisms (SNPs) showing an association of P < 5 × 10- 6 were selected to determine the replication of the associations, and meta-analysis of discovery GWAS and the replication analysis resulted in five genome-wide significant loci. The OSR1-WDR35 [rs7567283, G allele, beta (se) = -0.536 (0.096), P = 2.75 × 10- 8] locus was associated with the facial frontal contour; the HOXD1-MTX2 [rs970797, A allele, beta (se) = 0.015 (0.003), P = 3.97 × 10- 9] and WDR27 [rs3736712, C allele, beta (se) = 0.293 (0.048), P = 8.44 × 10- 10] loci were associated with eye shape; and the SOX9 [rs2193054, C allele, beta (se) (ln-transformed) = -0.007 (0.001), P = 6.17 × 10- 17] and DHX35 [rs2206437, A allele, beta (se) = -0.283 (0.047), P = 1.61 × 10- 9] loci were associated with nose shape. WDR35 and SOX9 were related to known craniofacial malformations, i.e., cranioectodermal dysplasia 2 and campomelic dysplasia, respectively. In addition, we found three independent association signals in the SOX9 locus, and six known loci for nose size and shape were replicated in this study population. Interestingly, four SNPs within these five face morphology-related loci showed discrepancies in allele frequencies among ethnic groups. CONCLUSIONS: We identified five novel face morphology loci that were associated with facial frontal contour, nose shape, and eye shape. Our findings provide useful genetic information for the determination of face morphology.

Inhibition of autophagy enhances dynamin inhibitor-induced apoptosis via promoting Bak activation and mitochondrial damage in human Jurkat T cells.

Treatment of Jurkat T cells with the dynamin inhibitor, myristyl trimethyl ammonium bromides (MiTMAB) caused cytokinesis impairment and apoptotic DNA fragmentation along with down-regulation of anti-apoptotic BAG3 and Mcl-1 levels, Bak activation, mitochondrial membrane potential (Δψm) loss, activation of caspase-9 and -3, and PARP cleavage, without accompanying necrosis. Bcl-xL overexpression completely abrogated these MiTMAB-induced mitochondrial damage and resultant caspase cascade activation, except for impaired cytokinesis and down-regulated BAG3 and Mcl-1 levels. Additionally, autophagic responses including Akt-mTOR pathway inhibition, formation of acridine orange-stainable acidic vesicular organelles, LC3-I/II conversion, and p62/SQSTM1 down-regulation were detected regardless of Bcl-xL overexpression. The autophagy inhibitors 3-methyladenine and LY294002 enhanced MiTMAB-induced apoptotic sub-G1 peak, BAG3 and Mcl-1 down-regulation, Bak activation, Δψm loss, and caspase activation. These results indicate that MiTMAB-caused cytokinesis failure leads to concomitant induction of apoptosis and cytoprotective autophagy, and suggest that inhibition of autophagy is a promising strategy to augment antitumor activity of MiTMAB.

Effects of electromagnetic field (PEMF) exposure at different frequency and duration on the peripheral nerve regeneration: in vitro and in vivo study.

PURPOSE: The purpose was to clarify the influence of frequency and exposure time of pulsed electromagnetic fields (PEMF) on the peripheral nerve regeneration. MATERIALS AND METHODS: Immortalized rat Schwann cells (iSCs) (1 × 10(2)/well) were exposed at four different conditions in 1 mT (50 Hz 1 h/d, 50 Hz 12 h/d, 150 Hz 1 h/d and 150 Hz 12h/d). Cell proliferation, mRNA expression of S100 and brain-derived neurotrophic factor (BDNF) were analyzed. Sprague-Dawley rats (200-250 g) were divided into six groups (n = 10 each): control, sham, 50 Hz 1 h/d, 50 Hz 12 h/d, 150 Hz 1 h/d and 150 Hz 12 Hr/d. Mental nerve was crush-injured and exposed at four different conditions in 1 mT (50 Hz 1 Hr/d, 50 Hz 12 Hr/d, 150 Hz 1 h/d and 150 Hz 12 h/d). Nerve regeneration was evaluated with functional test, histomorphometry and retrograde labeling of trigeminal ganglion. RESULTS: iSCs proliferation with 50 Hz, 1 h/d was increased from fourth to seventh day; mRNA expression of S100 and BDNF was significantly increased at the same condition from first week to third week (p < .05 vs. control); difference score was increased at the second and third week, and gap score was increased at the third under 50 Hz 1 h PEMF compared with control while other conditions showed no statistical meaning. Axon counts and retrograde labeled neurons were significantly increased under PEMF of four different conditions compared with control. Although there was no statistical difference, 50 Hz, 1 h PEMF showed highest regeneration ability than other conditions. CONCLUSION: PEMF enhanced peripheral nerve regeneration, and that it may be due to cell proliferation and increase in BDNF and S100 gene expression.

Nonsteroidal anti-inflammatory drug sulindac sulfide suppresses structural protein Nesprin-2 expression in colorectal cancer cells.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are well known for treating inflammatory disease and have been reported to have anti-tumorigenic effects. Their mechanisms are not fully understood, but both cyclooxygenase (COX) dependent and independent pathways are involved. Our goal was to shed further light on COX-independent activity. METHODS: Human colorectal cancer cells were observed under differential interference contrast microscopy (DICM), fluorescent microscopy, and micro-impedance measurement. Microarray analysis was performed using HCT-116 cells treated with sulindac sulfide (SS). PCR and Western blots were performed to confirm the microarray data and immunohistochemistry was performed to screen for Nesprin-2 expression. Micro-impedance was repeating including Nesprin-2 knock-down by siRNA. RESULTS: HCT-116 cells treated with SS showed dramatic morphological changes under DICM and fluorescent microscopy, as well as weakened cellular adhesion as measured by micro-impedance. Nesprin-2 was selected from two independent microarrays, based on its novelty in relation to cancer and its role in cell organization. SS diminished Nesprin-2 mRNA expression as assessed by reverse transcriptase and real time PCR. Various other NSAIDs were also tested and demonstrated that inhibition of Nesprin-2 mRNA was not unique to SS. Additionally, immunohistochemistry showed higher levels of Nesprin-2 in many tumors in comparison with normal tissues. Further micro-impedance experiments on cells with reduced Nesprin-2 expression showed a proportional loss of cellular adhesion. CONCLUSIONS: Nesprin-2 is down-regulated by NSAIDs and highly expressed in many cancers. GENERAL SIGNIFICANCE: Our data suggest that Nesprin-2 may be a potential novel oncogene in human cancer cells and NSAIDs could decrease its expression.

Biotransformation of d-Xylose-Rich Rice Husk Hydrolysate by a Rice Paddy Soil Bacterium, Priestia sp. Strain JY310, to Low Molecular Weight Poly(3-hydroxybutyrate).

Poly(3-hydroxybutyrate) (PHB) is a versatile thermoplastic with superior biodegradability and biocompatibility that is intracellularly accumulated by numerous bacterial and archaeal species. Priestia sp. strain JY310 that was able to efficiently biotransform reducing sugars in d-xylose-rich rice husk hydrolysate (reducing sugarRHH) to PHB was isolated from the soil of a rice paddy. Reducing sugarRHH including 12.5% d-glucose, 75.3% d-xylose, and 12.2% d-arabinose was simply prepared using thermochemical hydrolysis of 3% H2SO4-treated rice husk for 15 min at 121 °C. When cultured with 20 g/L reducing sugarRHH under optimized culture conditions in a batch bioreactor, Priestia sp. strain JY310 could produce PHB homopolymer up to 50.4% of cell dry weight (6.2 g/L). The melting temperature, heat of fusion, and thermal decomposition temperature of PHB were determined to be 167.9 °C, 92.1 J/g, and 268.1 °C, respectively. The number average and weight average molecular weights of PHB with a broad polydispersity index value (4.73) were estimated to be approximately 16.2 and 76.8 kg/mol, respectively. The findings of the present study suggest that Priestia sp. strain JY310 can be exploited as a good candidate for the low-cost production of low molecular weight PHB with improved biodegradability and reduced brittleness from inexpensive agricultural waste hydrolysates.

Immunolocalization of hemicelluloses in Arabidopsis thaliana stem. Part II: Mannan deposition is regulated by phase of development and its patterns of temporal and spatial distribution differ between cell types.

Microdistribution of mannans in Arabidopsis stem was examined using immunolocalization with mannan-specific monoclonal antibodies (LM21 and LM22). Mannan labeling in secondary xylem cells (except for protoxylem vessels) was initially detected in the cell wall during S(2) formation and increased gradually during development. Labeling in metaxylem vessels (vessels) was detected earlier than that in xylary fibers (fibers), but was much weaker than fibers. The S(1) layer of vessels and fibers showed much less labeling than the S(2) layer. Some strong labeling was also detected in pit membranes of vessel pits. Interfascicular fibers (If-fibers) showed more heterogeneous labeling patterns than fibers by LM21. Unlike fibers, If-fibers also revealed some strong labeling in the cell corner of the S(1) layer, indicating different mannan labeling patterns between If-fibers and fibers. Interestingly, protoxylem vessels (proto-vessels) showed strong labeling at the early stage of secondary xylem formation with more intense labeling in the outer- than inner cell wall even though fibers and vessels showed no or very low labeling at this stage. Labeling intensity of proto-vessels was also much stronger than vessels and stronger or slightly weaker than fibers by LM21 and LM22, respectively. Using pectinase and mild alkali treatment, the presence of mannans in parenchymatous cells was also confirmed. Together our observations indicate that there are temporal and spatial variations in mannan labeling between cell types in the secondary xylem of Arabidopsis stems. Some similar features of mannan labeling between Arabidopsis and poplar are also discussed.

Immunolocalization of hemicelluloses in Arabidopsis thaliana stem. Part I: temporal and spatial distribution of xylans.

We investigated the microdistribution of xylans in different cell types of Arabidopsis stem using immunolocalization methods with LM10 and LM11 antibodies. Xylan labeling in xylary fibers (fibers) was initially detected at the cell corner of the S(1) layer and increased gradually during fiber maturation, showing correlation between xylan labeling and general secondary cell wall formation processes in fibers. Metaxylem vessels (vessels) showed earlier development of secondary cell walls than fibers, but revealed almost identical labeling patterns to fibers during maturation. No difference in labeling patterns and intensity was detected in the cell wall of fibers, vessels and protoxylem vessels (proto-vessels) between LM10 and LM11, indicating that vascular bundle cells may be chemically composed of a highly homogeneous xylan type. Interestingly, interfascicular fibers (If-fibers) showed different labeling patterns between the two antibodies and also between different developmental stages. LM10 showed no labeling in primary cell walls and intercellular layers of If-fibers at the S(1) formation stage, but some labeling was detected in middle lamella cell corner regions at the S(2) formation stage. In contrast, LM11 revealed uniform labeling across the If-fiber cell wall during all developmental stages. These results suggest that If-fibers have different xylan deposition processes and patterns from vascular bundle cells. The presence of xylan was also confirmed in parenchyma cells following pectinase treatment. Together our results indicate that there are temporal and spatial differences in xylan labeling between cell types in Arabidopsis stem. Differences in xylan labeling between Arabidopsis stem and poplar are also discussed.

Distribution of glucomannans and xylans in poplar xylem and their changes under tension stress.

Present work investigated glucomannan (GM) and xylan distribution in poplar xylem cells of normal- (NW), opposite- (OW) and tension wood (TW) with immunolocalization methods. GM labeling was mostly detected in the middle- and inner S(2) (+S(3)) layer of NW and OW fibers, while xylan labeling was observed in the whole secondary cell wall. GM labeling in vessels of NW and OW was much weaker than in fibers and mostly detected in the S(2) layer, whereas slightly stronger xylan labeling than fibers was detected in the whole secondary cell wall of vessels. Ray cells in NW and OW showed no GM labeling, but strong xylan labeling. These results indicate that GMs and xylans are spatially distributed in poplar xylem cells with different concentrations present in different cell types. Surprisingly, TW showed significant decrease of GM labeling in the normal secondary cell wall of gelatinous (G) fibers compared to NW and OW, while xylan labeling was almost identical indicating that the GM and xylan synthetic pathways in fibers have different reaction mechanisms against tension stress. Unlike fibers, no notable changes in GM labeling were detected in vessels of TW, suggesting that GM synthesis in vessels may not be affected by tension stress. GM and xylan was also detected in the G-layer with slightly stronger and much weaker labeling than the normal secondary cell wall of G-fibers. Differences in GM and xylan distribution are also discussed for the same functional cells found in hardwoods and softwoods.

Spatial and temporal variability of xylan distribution in differentiating secondary xylem of hybrid aspen.

Xylans occupy approximately one-third of the cell wall components in hardwoods and their chemical structures are well understood. However, the microdistribution of xylans (O-acetyl-4-O-methylglucuronoxylans, AcGXs) in the cell wall and their correlation with functional properties of cells in hardwood xylem is poorly understood. We demonstrate here the spatial and temporal distribution of xylans in secondary xylem cells of hybrid aspen using immunolocalization with LM10 and LM11 antibodies. Xylan labeling was detected earliest in fibers at the cell corner of the S1 layer, and then later in vessels and ray cells respectively. Fibers showed a heterogeneous labeling pattern in the mature cell wall with stronger labeling of low substituted xylans (lsAcGXs) in the outer than inner cell wall. In contrast, vessels showed uniform labeling in the mature cell wall with stronger labeling of lsAcGXs than fibers. Xylan labeling in ray cells was detected much later than that in fibers and vessels, but was also detected at the beginning of secondary cell wall formation as in fibers and vessels with uniform labeling in the cell wall regardless of developmental stage. Interestingly, pit membranes including fiber-, vessel- and ray-vessel pits showed strong labeling of highly substituted xylans (hsAcGXs) during differentiation, although this labeling gradually disappeared during pit maturation. Together our observations indicate that there are temporal and spatial variations of xylan deposition and chemical structure of xylans between cells in aspen xylem. Differences in xylan localization between aspen (hardwood) and cedar (softwood) are also discussed.

Ultrastructure of the innermost surface of differentiating normal and compression wood tracheids as revealed by field emission scanning electron microscopy.

The ultrastructure of the innermost surface of Cryptomeria japonica differentiating normal wood (NW) and compression wood (CW) was comparatively investigated by field emission electron microscopy (FE-SEM) combined with enzymatic degradation of hemicelluloses. Cellulose microfibril (CMF) bundles were readily observed in NW tracheids in the early stage of secondary cell wall formation, but not in CW tracheids because of the heavy accumulation of amorphous materials composed mainly of galactans and lignin. This result suggests that the ultrastructural deposition of cell wall components in the tracheid cell wall differ between NW and CW from the early stage of secondary cell wall formation. Delignified NW and CW tracheids showed similar structural changes during differentiating stages after xylanase or ß-mannanase treatment, whereas they exhibited clear differences in ultrastructure in mature stages. Although thin CMF bundles were exposed in both delignified mature NW and CW tracheids by xylanase treatment, ultrastructural changes following ß-mannanase treatment were only observed in CW tracheids. CW tracheids also showed different degradation patterns between xylanase and ß-mannanase. CMF bundles showed a smooth surface in delignified mature CW tracheids treated with xylanase, whereas they had an uneven surface in delignified mature CW tracheids treated with ß-mannanase, indicating that the uneven surface of CMF bundles was related to xylans. The present results suggest that ultrastructural deposition and organization of lignin and hemicelluloses in CW tracheids may differ from those of NW tracheids.

Temporal and spatial diversities of the immunolabeling of mannan and xylan polysaccharides in differentiating earlywood ray cells and pits of Cryptomeria japonica.

Wood is composed of various types of cells and each type of cell has different structural and functional properties. However, the temporal and spatial diversities of cell wall components in the cell wall between different cell types are rarely understood. To extend our understanding of distributional diversities of cell wall components among cells, we investigated the immunolabeling of mannans (O-acetyl-galactoglucomannans, GGMs) and xylans (arabino-4-O-methylglucuronoxylans, AGXs) in ray cells and pits. The labeling of GGMs and AGXs was temporally different in ray cells. GGM labeling began to be detected in ray cells at early stages of S(1) formation in tracheids, whereas AGX labeling began to be detected in ray cells at the S(2) formation stage in tracheids. The occurrence of GGM and AGX labeling in ray cells was also temporally different from that of tracheids. AGX labeling began to be detected much later in ray cells than in tracheids. GGM labeling also began to be detected in ray cells either slightly earlier or later than in tracheids. In pits, GGM labeling was detected in bordered and cross-field pit membranes at early stages of pit formation, but not observed in mature pits, indicating that enzymes capable of GGM degradation may be involved in pit membrane formation. In contrast to GGMs, AGXs were not detected in pit membranes during the entire developmental process of bordered and cross-field pits. AGXs showed structural and depositional variations in pit borders depending on the developmental stage of bordered and cross-field pits.

Occurrence of xylan and mannan polysaccharides and their spatial relationship with other cell wall components in differentiating compression wood tracheids of Cryptomeria japonica.

Compression wood (CW) tracheids have different cell wall components than normal wood (NW) tracheids. However, temporal and spatial information on cell wall components in CW tracheids is poorly understood. We investigated the distribution of arabino-4-O-methylglucuronoxylans (AGXs) and O-acetyl-galactoglucomannans (GGMs) in differentiating CW tracheids. AGX labeling began to be detected in the corner of the S(1) layer at the early S(1) formation stage. Subsequently, the cell corner middle lamella (ccML) showed strong AGX labeling when intercellular spaces were not fully formed. AGX labeling was uniformly distributed in the S(1) layer, but showed uneven distribution in the S(2) layer. AGX labeling was mainly detected in the inner S(2) layer after the beginning of the helical cavity formation. The outer S(2) layer showed almost no labeling of low substituted AGXs. Only a very small amount of high substituted AGXs was distributed in the outer S(2) layer. These patterns of AGX labeling in the S(2) layer opposed the lignin and ß-1-4-galactan distribution in CW tracheids. GGM labeling patterns were almost identical to AGX labeling in the early stages of CW tracheids, and GGM labeling was detected in the entire S(2) layer from the early S(2) formation stage of CW tracheids with some spatial differences in labeling density depending on developmental stage. Compared with NW tracheids, CW tracheids showed significantly different AGX distributions in the secondary cell wall but similar GGM labeling patterns. No significant differences were observed in labeling after delignification of CW tracheids.

Thermogelling Behaviors of Aqueous Poly(N-Isopropylacrylamide-co-2-Hydroxyethyl Methacrylate) Microgel-Silica Nanoparticle Composite Dispersions.

Gelation behaviors of hydrogels have provided an outlook for the development of stimuli-responsive functional materials. Of these materials, the thermogelling behavior of poly(N-isopropylacrylamide) (p(NiPAm))-based microgels exhibits a unique, reverse sol-gel transition by bulk aggregation of microgels at the lower critical solution temperature (LCST). Despite its unique phase transition behaviors, the application of this material has been largely limited to the biomedical field, and the bulk gelation behavior of microgels in the presence of colloidal additives is still open for scrutinization. Here, we provide an in-depth investigation of the unique thermogelling behaviors of p(NiPAm)-based microgels through poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) microgel (p(NiPAm-co-HEMA))-silica nanoparticle composite to expand the application possibilities of the microgel system. Thermogelling behaviors of p(NiPAm-co-HEMA) microgel with different molar ratios of N-isopropylacrylamide (NiPAm) and 2-hydroxyethyl methacrylate (HEMA), their colloidal stability under various microgel concentrations, and the ionic strength of these aqueous solutions were investigated. In addition, sol-gel transition behaviors of various p(NiPAm-co-HEMA) microgel systems were compared by analyzing their rheological properties. Finally, we incorporated silica nanoparticles to the microgel system and investigated the thermogelling behaviors of the microgel-nanoparticle composite system. The composite system exhibited consistent thermogelling behaviors in moderate conditions, which was confirmed by an optical microscope. The composite demonstrated enhanced mechanical strength at gel state, which was confirmed by analyzing rheological properties.

Association of a common AGO1 variant with lung cancer risk: a two-stage case-control study.

Based on the important role of microRNA (miRNA) biosynthesis genes in carcinogenesis, we hypothesized that polymorphisms in the miRNA biosynthesis genes may modulate susceptibility to lung cancer. To test this hypothesis, we conducted a two-stage study to evaluate the associations between single nucleotide polymorphisms (SNPs) in the miRNA biosynthesis genes and the risk of lung cancer. In stage 1 of the study, 24 SNPs in the 11 miRNA biosynthesis genes (DROSHA, DGCR8, RAN, XPO5, DICER, AGO1, AGO2, HIWI, GEMIN3, GEMIN4, and TRBP) were genotyped in 100 lung cancer patients and 100 healthy controls using a sequenome mass spectrometry-based genotyping assay. One promising SNP (AGO1 rs636832A > G) was selected for stage 2 of the study, and genotyped by a melting-curve analysis using fluorescence-labeled hybridization probes in an independent set of 552 cases and 552 controls. The AGO1 rs636832A > G exhibited highly consistent results between the two stages of the study. In combined analysis, the 636832A > G was associated with a significantly decreased risk of lung cancer in a dose-dependent manner (P(trend) = 6.0 × 10(-4)). Individuals with at least one rs636832G allele were at a significantly decreased risk of lung cancer compared with those with the AA genotype (adjusted odds ratio = 0.67, 95% confidence interval = 0.53-0.84, P = 4.0 × 10(-4)). This finding suggests that the AGO1 rs636832A > G might be a useful marker for determining the susceptibility to lung cancer and that the AGO1 gene might be involved in the development of lung cancer.

Immunolocalization and structural variations of xylan in differentiating earlywood tracheid cell walls of Cryptomeria japonica.

We investigated the spatial and temporal distribution of xylans in the cell walls of differentiating earlywood tracheids of Cryptomeria japonica using two different types of monoclonal antibodies (LM10 and LM11) combined with immunomicroscopy. Xylans were first deposited in the corner of the S(1) layer in the early stages of S(1) formation in tracheids. Cell corner middle lamella also showed strong xylan labeling from the early stage of cell wall formation. During secondary cell wall formation, the innermost layer and the boundary between the S(1) and S(2) layers (S(1)/S(2) region) showed weaker labeling than other parts of the cell wall. However, mature tracheids had an almost uniform distribution of xylans throughout the entire cell wall. Xylan localization labeled with LM10 antibody was stronger in the outer S(2) layer than in the inner layer, whereas xylans labeled with LM11 antibody were almost uniformly distributed in the S(2) layer. In addition, the LM10 antibody showed almost no xylan labeling in the S(1)/S(2) region, whereas the LM11 antibody revealed strong xylan labeling in the S(1)/S(2) region. These findings suggest that structurally different types of xylans may be deposited in the tracheid cell wall depending on the developmental stage of, or location in, the cell wall. Our study also indicates that deposition of xylans in the early stages of tracheid cell wall formation may be spatially consistent with the early stage of lignin deposition in the tracheid cell wall.

Temporal and spatial immunolocalization of glucomannans in differentiating earlywood tracheid cell walls of Cryptomeria japonica.

We investigated the deposition of glucomannans (GMs) in differentiating earlywood tracheids of Cryptomeria japonica using immunocytochemical methods. GMs began to deposit at the corner of the cell wall at the early stages of S(1) formation and showed uneven distribution in the cell wall during S(1) formation. At the early stages of S(2) formation, limited GM labeling was observed in the S(2) layer, and then the labeling increased gradually. In mature tracheids, the boundary between the S(1) and S(2) layers and the innermost part of the cell wall showed stronger labeling than other parts of the cell wall. Deacetylation of GMs with mild alkali treatment led to a significant increase in GM labeling and a more uniform distribution of GMs in the cell wall than that observed before deacetylation, indicating that some GM epitopes may be masked by acetylation. However, the changes in GM labeling after deacetylation were not very pronounced until early stages of S(2) formation, indicating that GMs deposited in the cell wall at early stages of cell-wall formation may contain fewer acetyl groups than those deposited at later stages. Additionally, the density of GM labeling increased in the cell wall in both specimens before and after GM deacetylation, even after cell-wall formation was complete. This finding suggests that some acetyl groups may be removed from GMs after cell-wall formation is complete as part one of the tracheid cell aging processes.

Immunolocalization of beta-1-4-galactan and its relationship with lignin distribution in developing compression wood of Cryptomeria japonica.

Compression wood (CW) contains higher quantities of beta-1-4-galactan than does normal wood (NW). However, the physiological roles and ultrastructural distribution of beta-1-4-galactan during CW formation are still not well understood. The present work investigated deposition of beta-1-4-galactan in differentiating tracheids of Cryptomeria japonica during CW formation using an immunological probe (LM5) combined with immunomicroscopy. Our immunolabeling studies clearly showed that differences in the distribution of beta-1-4-galactan between NW (and opposite wood, OW) and CW are initiated during the formation of the S(1) layer. At this stage, CW was strongly labeled in the S(1) layer, whereas no label was observed in the S(1) layer of NW and OW. Immunogold labeling showed that beta-1-4-galactan in the S(1) layer of CW tracheids significantly decreased during the formation of the S(2) layer. Most beta-1-4-galactan labeling was present in the outer S(2) region in mature CW tracheids, and was absent in the inner S(2) layer that contained helical cavities in the cell wall. In addition, delignified CW tracheids showed significantly more labeling of beta-1-4-galactan in the secondary cell wall, suggesting that lignin is likely to mask beta-1-4-galactan epitopes. The study clearly showed that beta-1-4-galactan in CW was mainly deposited in the outer portion of the secondary cell wall, indicating that its distribution may be spatially consistent with lignin distribution in CW tracheids of Cryptomeria japonica.

Comparison of the Decay Behavior of Two White-Rot Fungi in Relation to Wood Type and Exposure Conditions.

Fungal wood decay strategies are influenced by several factors, such as wood species, moisture content, and temperature. This study aims to evaluate wood degradation characteristics of spruce, beech, and oak after exposure to the white-rot fungi Pleurotusostreatus and Trametesversicolor. Both fungi caused high mass losses in beech wood, while spruce and oak wood were more resistant to decay. The moisture content values of the decayed wood correlated with the mass losses for all three wood species and incubation periods. Combined microscopic and chemical studies indicated that the two fungi differed in their decay behavior. While T. versicolor produced a decay pattern (cell wall erosion) typical of white-rot fungi in all wood species, P. ostreatus caused cell wall erosion in spruce and beech and soft-rot type I (cavity formation) decay in oak wood. These observations suggest that P. ostreatus may have the capacity to produce a wider range of enzymes/radicals triggered by the chemical composition of wood cell walls and/or local compositional variability within the cell wall.