Functional genomics of wood quality and properties

Genomics promises to enrich the investigations of biology and biochemistry. Current advancements in genomics have major implications for genetic improvement in animals, plants, and microorganisms, and for our understanding of cell growth, development, differentiation, and communication. Significant progress has been made in the understanding of plant genomics in recent years, and the area continues to     

Anti-u.v. activity of lignin biopolymers on Euglena gracilis

Sulphur-free lignin biopolymer and its oxidized and reduced derivatives have been prepared and their inhibitory activity against u.v.-induced mutagenesis in Euglena gracilis was evaluated. The structure- and dose-dependent anti-u.v. activity of lignins was observed at concentrations higher than 250gml^–1. The oxidized lignin showed the most antimutagenic activity, followed by the reduced lignin and the unmodified lignin had the least antimutagenic activity.     

Residual lignin studies of laccase-delignified kraft pulps

The delignification of chemical pulps with laccase and -hydroxybenzotriazole was explored employing a pre- and post-O₂ delignified softwood draft pulp. The delignification properties of laccase were shown to be improved with -hydroxybenzotriazole was used as a mediator instead of 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid). Analysis of the structure of residual lignin before and after laccase/ -hydroxybenzotriazole treatment indicated that the biobleaching system oxidizes the phenolic component of lignin and that the residual lignin is demethylated and significantly enriched in carboxylic acid groups.     

Nutrient dynamics and lignocellulose degradation in decomposing Quercus serrata leaf litter

The litter mass loss, concentration and mass of some major nutrient elements, degradation of lignin and cellulose in decomposing Quercus serrata Murray leaf litter were monitored for 3 years using the litterbag method. The mobility of elements during the course of the study was in the order of: K > P > C > Mg > Ca > N. Three patterns of nutrient dynamics were observed: (i) concentration increased while mass decreased (N, Mg and Ca); (ii) concentration and nutrient mass decreased (K and C); and (iii) both concentration and mass had fluctuated (P). The C to element ratio tended to increase as the element was released, and decreased as the element was retained. Nitrogen mobility in relation to carbon was characterized by three phases: (i) initial release; (ii) accumulation and (iii) final release. The decay rate (k) calculated from 0–6 months period was overestimated for an average annual rate while those of 0–36 months fit the negative single exponential model (Adj. r² = 0.99) better than shorter periods. For lignin, the concentration had increased then decreased but tended to stabilize after 1 year while the lignin mass had continuously decreased throughout the study period. During the first 9 months, both the concentrations and mass of cellulose had fluctuated but declined thereafter. The amounts of N had initially increased but declined after 1 year; P had fluctuated while K, Ca, Mg and C had decreased throughout the study. N and C/N ratio exerted strong influence on mass loss during the first24 months but the influence of lignin emerged after 24 months.     

A novel aromatic alcohol dehydrogenase in higher plants: molecular cloning and expression

Cinnamyl alcohol dehydrogenase (CAD; EC 1.1.195) catalyses the conversion of p-hydroxy-cinnamaldehydes to the corresponding alcohols and is considered a key enzyme in lignin biosynthesis. In a previous study, an atypical form of CAD (CAD 1) was identified in Eucalyptus gunnii [12]. We report here the molecular cloning and characterization of the corresponding cDNA, CAD 1-5, which encodes this novel aromatic alcohol dehydrogenase. The identity of CAD 1-5 was unambiguously confirmed by sequence comparison of the cDNA with peptide sequences derived from purified CAD 1 protein and by functional expression of CAD 1 recombinant protein in Escherichia coli. Both native and recombinant CAD 1 exhibit high affinity towards lignin precursors including 4-coumaraldehyde and coniferaldehyde, but they do not accept sinapaldehyde. Moreover, recombinant CAD 1 can also utilize a wide range of aromatic substrates including unsubstituted and substituted benzaldehydes. The open reading frame of CAD 1-5 encodes a protein with a calculated molecular mass of 35790 Da and an isoelectric point of 8.1. Although sequence comparisons with proteins in databases revealed significant similarities with dihydroflavonol-4-reductases (DFR; EC 1.1.1.219) from a wide range of plant species, the most striking similarity was found with cinnamoyl-CoA reductase (CCR; EC 1.2.1.44), the enzyme which directly precedes CAD in the lignin biosynthetic pathway. RNA blot analysis and immunolocalization experiments indicated that CAD 1 is expressed in both lignified and unlignified tissues/cells. Based on the catalytic activity of CAD 1 in vitro and its localization in planta, CAD 1 may function as an alternative enzyme in the lignin biosynthetic pathway. However, additional roles in phenolic metabolism are not excluded.     

PEP-1-FK506BP inhibits alkali burn-induced corneal inflammation on the rat model of corneal alkali injury

FK506 binding protein 12 (FK506BP) is a small peptide with a single FK506BP domain that is involved in suppression of immune response and reactive oxygen species. FK506BP has emerged as a potential drug target for several inflammatory diseases. Here, we examined the protective effects of directly applied cell permeable FK506BP (PEP-1-FK506BP) on corneal alkali burn injury (CAI). In the cornea, there was a significant decrease in the number of cells expressing pro-inflammation, apoptotic, and angiogenic factors such as TNF-α, COX-2, and VEGF. Both corneal opacity and corneal neovascularization (CNV) were significantly decreased in the PEP-1-FK506BP treated group. Our results showed that PEP-1-FK506BP can significantly inhibit alkali burn-induced corneal inflammation in rats, possibly by accelerating corneal wound healing and by reducing the production of angiogenic factors and inflammatory cytokines. These results suggest that PEP-1-FK506BP may be a potential therapeutic agent for CAI. [BMB Reports 2015; 48(11): 618-623]     

An effective chemical pretreatment method for lignocellulosic biomass with substituted imidazoles

Lignocellulosic biomass is the most abundant naturally renewable organic resource for biofuel production. Because of its recalcitrance to enzymatic degradation, pretreatment is a crucial step before hydrolysis of the feedstock. A variety of pretreatment methods have been developed and intensively studied to achieve optimal yield without imposing significant adverse impact on the environment. Herein, we present a novel chemical pretreatment method using substituted heterocycles with low temperature and short residence time requirements. 1‐Methylimidazole (MI) is a precursor to some imidazolium‐based ionic liquids. In this study, its potential utilization as a biomass pretreatment agent is being investigated for the first time. At mild conditions, such as 25°C for 5 min at ambient pressure, a substantial increase in the hydrolysis rate throughout the entire course of conversion for cellulose substrate was obtained. Furthermore, the pretreatment effectiveness of MI on both untreated and steam‐exploded lignocellulosic biomass including loblolly pine, switchgrass, and sugarcane bagasse has been studied and MI was found to be an efficient delignifier. Remarkable rate enhancement was also observed for the non‐woody lignocellulosic substrates after a short period of MI pretreatment at ambient conditions. The mechanism of MI pretreatment is explored through analysis of cellulose physical properties including crystallinity index, degree of polymerization, accessibility, and lignin dissolution quantification. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 31:25–34, 2015     

木瓜籽毛油精炼条件筛选及其理化指标分析

以磷脂含量为指标对木瓜〔Chaenomeles sinensis ( Thouin) Koehne〕籽毛油水化脱胶过程中脱胶剂种类、脱胶剂添加量、脱胶时间、加水量和脱胶温度进行单因素实验,并在此基础上对脱胶时间、加水量和脱胶温度进行L9(33)正交实验;以酸价为指标对碱炼脱酸过程中的碱液(NaOH溶液)浓度、碱炼温度和超碱用量进行单因素实验和L9(33)正交实验;并比较了毛油、脱胶油、脱酸油和精炼油的主要理化指标变化。单因素实验和正交实验结果表明：在木瓜籽毛油水化脱胶过程中采用不同的脱胶剂种类(包括柠檬酸、草酸和蒸馏水)、脱胶剂添加量(质量分数0.1%~0.5%)、脱胶时间(10~70 min)、加水量(质量分数1%~6%)和脱胶温度(65℃~85℃),毛油中的磷脂含量均有明显差异;而碱炼脱酸过程中采用不同的碱液浓度(质量分数6%~14%)、碱炼温度(40℃~80℃)和超碱用量(质量分数0.15%~0.40%),毛油酸价也有明显变化。总体上看,木瓜籽毛油水化脱胶的适宜条件为添加质量分数0.2%柠檬酸为脱胶剂、脱胶温度75℃、加水量为质量分数4%、脱胶时间50 min;碱炼脱酸的适宜条件为碱液浓度为质量分数12%、碱炼温度80℃、超碱用量为质量分数0.30%。理化指标的测定结果表明：与毛油相比,脱胶油、脱酸油和精炼油的碘值略升高但差异不明显、过氧化值明显升高、磷脂含量和皂化值均明显下降,而脱酸油和精炼油的酸价也明显下降。研究结果显示：经过脱胶、脱酸、水洗干燥一系列过程后获得的木瓜籽精炼油的理化指标基本符合国家食用植物油卫生标准。