OsMYB108 loss-of-function enriches p-coumaroylated and tricin lignin units in rice cell walls.

Breeding approaches to enrich lignins in biomass could be beneficial to improving the biorefinery process because lignins increase biomass heating value and represent a potent source of valuable aromatic chemicals. However, despite the fact that grasses are promising lignocellulose feedstocks, limited information is yet available for molecular-breeding approaches to upregulate lignin biosynthesis in grass species. In this study, we generated lignin-enriched transgenic rice (Oryza sativa), a model grass species, via targeted mutagenesis of the transcriptional repressor OsMYB108 using CRISPR/Cas9-mediated genome editing. The OsMYB108-knockout rice mutants displayed increased expressions of lignin biosynthetic genes and enhanced lignin deposition in culm cell walls. Chemical and two-dimensional nuclear magnetic resonance (NMR) analyses revealed that the mutant cell walls were preferentially enriched in γ-p-coumaroylated and tricin lignin units, both of which are typical and unique components in grass lignins. NMR analysis also showed that the relative abundances of major lignin linkage types were altered in the OsMYB108 mutants.

Nitrogen deficiency results in changes to cell wall composition of sorghum seedlings.

Sorghum [Sorghum bicolor (L.) Moench] has been gaining attention as a feedstock for biomass energy production. While it is obvious that nitrogen (N) supply significantly affects sorghum growth and biomass accumulation, our knowledge is still limited regarding the effect of N on the biomass quality of sorghum, such as the contents and structures of lignin and other cell wall components. Therefore, in this study, we investigated the effects of N supply on the structure and composition of sorghum cell walls. The cell walls of hydroponically cultured sorghum seedlings grown under sufficient or deficient N conditions were analyzed using chemical, two-dimensional nuclear magnetic resonance, gene expression, and immunohistochemical methods. We found that the level of N supply considerably affected the cell wall structure and composition of sorghum seedlings. Limitation of N led to a decrease in the syringyl/guaiacyl lignin unit ratio and an increase in the amount and alteration of tissue distribution of several hemicelluloses, including mixed linkage (1 → 3), (1 → 4)-ß-D-glucan, and arabinoxylan. At least some of these cell wall alterations could be associated with changes in gene expression. Nitrogen status is thus one of the factors affecting the cell wall properties of sorghum seedlings.

Analysis of exposed cellulose surfaces in pretreated wood biomass using carbohydrate-binding module (CBM)-cyan fluorescent protein (CFP).

In enzymatic saccharification of lignocellulosics, the access of the enzymes to exposed cellulose surfaces is a key initial step in triggering hydrolysis. However, knowledge of the structure-hydrolyzability relationship of the pretreated biomass is still limited. Here we used fluorescent-labeled recombinant carbohydrate-binding modules (CBMs) from Clostridium josui as specific markers for crystalline cellulose (CjCBM3) and non-crystalline cellulose (CjCBM28) to analyze the complex surfaces of wood tissues pretreated with NaOH, NaOH-Na(2)S (kraft pulping), hydrothermolysis, ball-milling, and organosolvolysis. Japanese cedar wood, one of the most recalcitrant softwood species was selected for the analysis. The binding analysis clarified the linear dependency of the exposure of crystalline and non-crystalline cellulose surfaces for enzymatic saccharification yield by the organosolv and kraft delignification processes. Ball-milling for 5-30 min increased saccharification yield up to 77%, but adsorption by the CjCBM-cyan fluorescent proteins (CFPs) was below 5%. Adsorption of CjCBM-CFPs on the hydrothermolysis pulp were less than half of those for organosolvolysis pulp, in coincidence with low saccharification yields. For all the pretreated wood, crystallinity index was not directly correlated with the overall saccharification yield. Fluorescent microscopy revealed that CjCBM3-CFP and CjCBM28-CFP were site-specifically adsorbed on external fibrous structures and ruptured or distorted fiber surfaces. The assay system with CBM-CFPs is a powerful measure to estimate the initiation sites of hydrolysis and saccharification yields from chemically delignified wood pulps.

Double knockout of OsWRKY36 and OsWRKY102 boosts lignification with altering culm morphology of rice.

Breeding to enrich lignin, a major component of lignocelluloses, in plants contributes to enhanced applications of lignocellulosic biomass into solid biofuels and valuable aromatic chemicals. To collect information on enhancing lignin deposition in grass species, important lignocellulose feedstocks, we generated rice (Oryza sativa) transgenic lines deficient in OsWRKY36 and OsWRKY102, which encode putative transcriptional repressors for secondary cell wall formation. We used CRISPR/Cas9-mediated targeted mutagenesis and closely characterized their altered cell walls using chemical and nuclear magnetic resonance (NMR) methods. Both OsWRKY36 and OsWRKY102 mutations significantly increased lignin content by up to 28 % and 32 %, respectively. Additionally, OsWRKY36/OsWRKY102-double-mutant lines displayed lignin enrichment of cell walls (by up to 41 %) with substantially altered culm morphology over the single-mutant lines as well as the wild-type controls. Our chemical and NMR analyses showed that relative abundances of guaiacyl and p-coumarate units were slightly higher and lower, respectively, in the WRKY mutant lignins compared with those in the wild-type lignins. Our results provide evidence that both OsWRKY36 and OsWRKY102 are associated with repression of rice lignification.

Differential expression of mucin core proteins and keratins in apocrine carcinoma, extramammary Paget's disease and apocrine nevus.

BACKGROUND: Apocrine carcinomas are rare, the immunohistochemical characterizations that are incomplete. The purpose of this study was to determine the immunohistochemical characteristics of mucin core proteins and keratins in apocrine carcinoma, extramammary Paget's disease (EMPD) and apocrine nevus. METHODS: We report four cases of apocrine carcinomas along with immunohistochemical analyses: (i) an axillary apocrine carcinoma with an apocrine nevus, (ii) an inguinal apocrine carcinoma, (iii) a vulvar apocrine carcinoma with EMPD and (iv) an axillary apocrine carcinoma with EMPD and an apocrine nevus. RESULTS: The tumor cells of apocrine carcinomas, EMPD and apocrine nevi displayed a positive reaction to MUC-1 and CK7 and a negative reaction to CK20. Apocrine carcinomas had high molecular weight (HMW) cytokeratin(+)/CK5(+)/CK14(-)/MUC5AC(-), EMPD with underlying apocrine carcinoma had HMW cytokeratin(-)/CK5(-)/CK14(-)/MUCA5AC(-) and the apocrine nevi had HMW cytokeratin(+)/CK5(+)/CK14(+)/MUCA5AC(+). CONCLUSION: The immunohistochemical findings suggest that apocrine carcinomas, apocrine nevi and EMPD with underlying apocrine carcinomas are quite different, even though they are all derived from apocrine glands.

Two cases of primary small cell carcinoma of the stomach.

We report 2 cases of small cell carcinoma (SmCC) of the stomach with distant metastasis that were treated with the same chemotherapeutic regimens as used to treat small cell lung cancer. Although the mean survival of patients with SmCC of the stomach is reported to be only 7 months, our patients survived for 15 and 14 months, respectively. In our experience, these chemotherapeutic regimens might provide a survival benefit for patients with SmCC of the stomach, although they demonstrated no remarkable antitumor effects.

Chemometric analysis with near-infrared spectroscopy for chemically pretreated Erianthus toward efficient bioethanol production.

In this paper, we report the combination of a near-infrared (NIR) spectroscopic method with multivariate analysis in order to develop a calibration model of the saccharification ratio of chemically pretreated Erianthus. The regression models clearly depend on the NIR spectral regions, and the information of CH and aromatic framework vibrations contributed most effectively to the alkaline dataset. From interpretations of the regression coefficient, lignin and cellulose were negatively and positively correlated with the saccharification ratio, respectively, and this result was supported by the data from wet chemical analysis. A more complex dataset was obtained from varied chemical pretreatments; here, the saccharification ratio was either small or had no linear correlation with each structural monocomponent. These results enabled the successful construction of the PLS regression model. NIR spectroscopy can be a rapid screening method for the saccharification ratio, and furthermore, can provide information of the key factors influencing the realization of more efficient enzymatic accessibility.

Near-infrared chemometric approach to exhaustive analysis of rice straw pretreated for bioethanol conversion.

We report a simple analytical procedure combining near-infrared (NIR) spectroscopy with multivariate analysis to detect the saccharification efficiency of pretreated rice straw. Three types of sample preparation methods were tested to develop a powerful calibration model, with the disk sample used as the standard protocol. From the spectra dataset of NaOH-treated biomass, we obtained a good calibration for the saccharification ratio and some major structural components by partial least-squares regression. Adding dataset from hot water and dilute sulfuric acid pretreatments to NaOH sample dataset, an acceptable calibration model to predict the saccharification ratio as well as the glucose, xylose, and lignin contents was generated. NIR has a great potential for rapid screening of saccharification efficiency of pretreated biomass, which would allows us to control the quality of processing toward better bioethanol production.

Surface carbohydrate analysis and bioethanol production of sugarcane bagasse pretreated with the white rot fungus, Ceriporiopsis subvermispora and microwave hydrothermolysis.

Effects of pretreatments with a white rot fungus, Ceriporiopsis subvermispora, and microwave hydrothermolysis of bagasse on enzymatic saccharification and fermentation were evaluated. The best sugar yield, 44.9 g per 100g of bagasse was obtained by fungal treatments followed by microwave hydrothermolysis at 180°C for 20 min. Fluorescent-labeled carbohydrate-binding modules which recognize crystalline cellulose (CjCBM3-GFP), non-crystalline cellulose (CjCBM28-GFP) and xylan (CtCBM22-GFP) were applied to characterize the exposed polysaccharides. The microwave pretreatments with and without the fungal cultivation resulted in similar levels of cellulose exposure, but the combined treatment caused more defibration and thinning of the plant tissues. Simultaneous saccharification and fermentation of the pulp fractions obtained by microwave hydrothermolysis with and without fungal treatment, gave ethanol yields of 35.8% and 27.0%, respectively, based on the holocellulose content in the pulp. These results suggest that C. subvermispora pretreatment could be beneficial part of the process to produce ethanol from bagasse.

Microwave-assisted pretreatment of recalcitrant softwood in aqueous glycerol.

Microwave-assisted pretreatment of recalcitrant softwood in aqueous glycerol containing a series of organic and inorganic acids with different pK(a) values was examined. The pulp obtained by organosolvolysis with 0.1% hydrochloric acid (pK(a) -6) at 180 degrees C for 6 min gave the highest sugar yield, 53.1%, based on the weight of original biomass. The pretreatment efficiency correlated linearly with the pK(a) of the acids, with the exception of malonic and phosphoric acids. Organosolvolysis with 1.0% phosphoric acid (pK(a) 2.15) gave a saccharification yield (50.6%) higher than that expected from its pK(a), while the catalytic effect of malonic acid (pK(a) 2.83) was negligible. Extensive exposure of crystalline and non-crystalline cellulose by the glycerolysis with strong inorganic acids was demonstrated by using fluorescent-labeled recombinant carbohydrate-binding modules (CBMs). Because of the low concentration of the acid catalysts and availability of glycerol as a by-product from biodiesel and fatty acid production, organosolvolysis in glycerol is an appealing process for pretreatment of recalcitrant softwood.

Recognition of cellooligosaccharides by a family 28 carbohydrate-binding module.

The crystal structures of a carbohydrate-binding module (CBM) family 28 domain of endoglucanase Cel5A from Clostridium josui have been determined in ligand-free and complex forms with cellobiose, cellotetraose, and cellopentaose as the first complex structures of this family. In the cleft of a beta-sandwich fold, the ligands are recognized by stacking interactions and hydrogen bonds. Conformations of the bound cellooligosaccharides are similar to those in crystals and solution but clearly different from the cellulose structure. Interestingly, the glucan chain bound on CBM28 is in the opposite direction of that bound to CBM17, although these families share significant structural similarity.