Cloning and Bioimformatic Analysis of Cellulose Synthase-like Protein Gene,CICsID1 from Cunninghamia lanceolata

The protein structure of the cellulose synthase-like protein(CSL) was similar to cellulose synthase(CesA),including the conservative sequence D,D,D,QXXRW.One full-length cDNA of the cellulose synthase-like protein D(CslD) gene was cloned by reverse transcriptase(RT)-polymerase chain reaction(PCR) with 5’,3’ rapid amplification of cDNA ends(RACE) methods using degenerate primers designed from the homologous sequences of the CesA genes.A multiple comparison sequence analysis was conducted concurrently with bioinformatic methods to analyze the obtained sequence.Results of the sequence analysis showed that this cDNA was 4 150 bp in length and contained a single open reading frame encoding a protein of 1 132 amino acids.The multiple comparison sequence analysis showed that the deduced amino acid sequence shared high similarity (over 71%) with the ClCslD genes from Populus tremuloides,Oryza sativa,and Arabidopsis thaliana. This work will help lay an important foundation for further molecular studies with cellulose synthesis of plants.

Effects of protein and lignin on cellulose and xylan anaylses of lignocellulosic biomass

Interactions of lignocellulosic components during fiber analysis were investigated using the highly adopted compositional analysis procedure from the National Renewable Energy Laboratory（NREL）,USA.Synthetic feedstock samples were used to study the effects of lignin/protein,cellulose/protein,and xylan/protein interaction on carbohydrate analysis.Disregarding structural influence in the synthetic samples,lignin and protein components were the most significant（P〈0.05）factors on cellulose analysis.Measured xylan was consistent and unaffected by content variation throughout the synthetic analysis.Validation of the observed relationships from synthetic feedstocks was fulfilled using real lignocellulosic feedstocks：corn stover,poplar,and alfalfa,in which similar results have been obtained,excluding cellulose analysis of poplar under higher protein content and xylan analysis of alfalfa under higher protein content.The results elucidated that according to their protein and lignin contents of different lignocellulosic materials,accuracy of the NREL method on cellulose and xylan analyses could be improved by applying a stronger extraction step to replace water/ethanol extraction.

Predicting Levels of Crude Protein, Digestibility, Lignin and Cellulose in Temperate Pastures Using Hyperspectral Image Data

Hyperspectral sensors provide the potential for direct estimation of pasture feed quality attributes. However, remote sensing retrieval of digestibility and fibre (lignin and cellulose) content of vegetation has proven to be challenging since tissue optical properties may not be propagated to the canopy level in mixed cover types. In this study, partial least squares regression on spectra from HyMap and Hyperion imagery were used to construct predictive models for estimation of crude protein, digestibility, lignin and cellulose concentration in temperate pastures. HyMap and Hyperion imagery and field spectra were collected over four pasture sites in southern Victoria, Australia. Co-incident field samples were analyzed with wet chemistry methods for crude protein, lignin and cellulose concentration, and digestibility was calculated from fiber determinations. Spectral data were subset based on sites and time of year of collection. Reflectance spectra were extracted from the hyperspectral imagery and collated for analysis. Six different transformations including derivatives and continuum removal were applied to the spectra to enhance absorption features sensitive to the quality attributes. The transformed reflectance spectra were then subjected to partial least squares regression, with full cross-validation “leave-one-out” technique, against the quality attributes to assess effects of the spectral transformations and post-atmospheric smoothing techniques to construct predictive models. Model performance between spectrometers, subsets and attributes were assessed using a coefficient of variation (CV), —the interquantile (IQ) range of the attribute values divided by the root mean square error of prediction (RMSEP) from the models. The predictive models with the highest CVs were obtained for digestibility for all spectra types, with HyMap the highest. However, models with slightly lower CVs were obtained for crude protein, lignin and cellulose. The spectral regions for diagnostic wavelengths fell within the chlorophyll well, red edge, and 2000-2300 nm ligno-cellulose-protein regions, with some wavelengths selected between the 1600 and 1800 nm region sensitive to nitrogen, protein, lignin and cellulose. The digestibility models with the highest CV’s had confidence intervals corresponding to ±5% digestibility, which constitutes approximately 30% of the measured range. The cellulose and lignin models with the highest CV’s also had similar confidence intervals but the slopes of the prediction lines were substantially less than 1:1 indicating reduced sensitivity. The predictive relationships established here could be applied to categorizing pasture quality into range classes and to determine whether pastures are above or below for example threshold values for livestock productivity benchmarks.

Cellulose-based Polymeric Liquid Crystals as a Biomimetic Modifier for Suppressing Protein Adsorption

A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described（PLCs）. Two types of PLCs of propyl hydroxypropyl cellulose ester（PPC） and octyl hydroxypropyl cellulose ester（OPC） were prepared by esterification from hydroxypropyl cellulose, and then were mixed with polyvinyl chloride and polyurethane to obtain composite films by solution casting, respectively. The surface morphology of PLCs and their composite films were characterized by polarized optical microscopy（POM） and scanning electron microscopy（SEM）, suggesting the existence of microdomain separation with fingerprint texture in PLC composite films. Water contact angle measurement results indicated that hydrophilicity of PLC/polymer composite films was dependent on the type and content of PLC as well as the type of matrix due to their interaction. Using bovine serum albumin（BSA） as a model protein, protein adsorption results revealed that PLCs with protein-resistant property can obviously suppress protein adsorption on their composite films, probably due to their flexible LC state. Moreover, all PLCs and their composites exhibited non-toxicity by MTT assay, suggesting their safety for biomedical applications.

In vitro demonstration of interactions among zinc-binding domains of cellulose synthases in Arabidopsis and aspen

Plant cellulose synthases (CesAs) are the key enzymes necessary for cellulose biosynthesis. In Arabidopsis, two distinct groups of three CesAs each are necessary for cellulose synthesis during primary and secondary cell wall formation. It has also been suggested that such three CesAs interact with each other to form plasma-membrane bound rosette complexes that are functional during cellulose production. However, in vivo demonstration of such assemblies of three CesAs into rosettes has not been possible. We used yeast two-hybrid assays to demonstrate the possible interactions among several CesAs from Arabidopsis and aspen via their N-terminal zinc-binding domains (ZnBDs). While strong positive interactions were detected among ZnBDs from secondary wall associated CesAs of both Arabidopsis and aspen, the intergeneric interactions between Arabidopsis and aspen CesAs were weak. Moreover, in aspen, three primary wall associated CesA ZnBDs positively interacted with each other as well as with secondary CesAs. These results suggest that ZnBDs from either primary or secondary CesAs, and even from different plant species could interact but are perhaps insufficient for specificities of such interactions among CesAs. These observations suggest that some other more specific interacting regions might exist within CesAs. It is also possible that some hitherto unknown mechanism exists in plants for assembling the rosette complexes with different compositions of CesAs. Understanding how cellulose is synthesized will have a direct impact on utilization of lignocellulosic biomass for bioenergy production.

生物基水凝胶纤维的研究现状

水凝胶纤维兼具纤维的一维宏观结构和水凝胶的三维微观结构,已成为新型纤维材料领域的国内外研究热点,尤其是生物相容性好、可自然降解的生物基水凝胶纤维备受关注。为了全面系统地了解生物基水凝胶纤维的研究现状与发展趋势,文章综述了蛋白质基、纤维素基、藻酸盐基等多类生物基水凝胶纤维的国内外研究成果,总结了生物基水凝胶纤维的制备方法、主要性能特征及复合优势。其中,以丝素蛋白、胶原蛋白为代表的蛋白质基水凝胶纤维具有良好的可塑性;纤维素材料多以物理交联形式构筑水凝胶纤维并常作为增强材料;复合型藻酸盐基水凝胶纤维制备形式多样且适用范围广。此外,阐述了生物基水凝胶纤维在伤口敷料、药物输送、组织工程等生物医学领域及在应变、压力、温度和湿度传感等领域的应用,并提出了研制基于自然界生物质材料的水凝胶纤维所面临的机遇和挑战,为进一步制备高性能、多功能且绿色环保的生物基水凝胶纤维提供了参考。

羧甲基纤维素的添加对蛋清蛋白功能特性的协同效应的影响

为了提高蛋清蛋白的功能性质,分别向蛋清蛋白溶液中加入0.2‰、0.4‰、0.6‰、0.8‰、1.0‰的羧甲基纤维素(CMC),研究蛋白-多糖混合体系的流变、质构、起泡性和差示热量扫描分析的变化。结果表明:羧甲基纤维素添加到蛋清蛋白溶液提高了起泡性,0.8‰CMC-蛋清蛋白泡沫稳定性最优。对于其回复性、咀嚼性、硬度、凝聚力和弹性也呈增强趋势,0.8‰CMC-蛋清蛋白的硬度和咀嚼性最优,其他性能均与1.0‰CMC-蛋清蛋白差别不大。热性能和流变性能表明CMC的加入提高了共混体系的热稳定性,0.8‰CMC-蛋清蛋白的溶胶转变温度达到最大值。

实验教学中醋酸纤维素薄膜电泳的条件优化

醋酸纤维素薄膜电泳分离血清蛋白是生物化学实验课中的一项基础实验技术。目前,诸多医学院校基础医学及生物学专业均开设了此项实验。但是由于实验方法的不同,且实验过程中的影响因素较多,学生获得的实验结果也存在多种问题。经过多年实验教学探索,西安交通大学医学部基础医学院生物化学与分子生物系实验教学团队优化了醋酸纤维素薄膜电泳分离血清蛋白的实验方案,增强了实验教学内容的互动性,确保了实验结果的稳定性,使学生更好地掌握了水平电泳分离蛋白质的理论知识并获得了成功的实验验证。

SsdchA is a novel secretory cellobiohydrolase driving pathogenicity in Sclerotinia sclerotiorum

The necrotrophic fungus, Sclerotinia sclerotiorum, employs an array of cell wall-degrading enzymes(CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which S. sclerotiorum degrades cellulose remain elusive. Here, we unveil a novel secretory cellobiohydrolase, SsdchA, characterized by a signal peptide and a Glyco_hydro_7(GH7) domain. SsdchA exhibits a robust expression of during early infection stages. Interestingly, colony morphology and growth rates remain unaffected across the wild-type, SsdchA deletion strains and SsdchA overexpression strains on potato dextrose agar(PDA) medium. Nevertheless, the pathogenicity and cellobiohydrolase activity decreased in the SsdchA deletion strains, but enhanced in the SsdchA overexpression strains. Moreover,the heterologous expression of SsdchA in Arabidopsis thaliana leads to reduced cellulose content and heightened susceptibility to S. sclerotiorum. Collectively, our data underscore the pivotal role of the novel cellobiohydrolase SsdchA in the pathogenicity of S. sclerotiorum.

利用热重红外联用技术快速鉴别单组分纺织纤维

基于纤维在程序升温过程中热解产生逸出气的红外光谱与其结构的密切关系,文章提出利用热重红外联用技术(TG/FTIR)快速鉴别纺织纤维的新方法。检测了15种常用纺织纤维,发现合成纤维、蛋白质纤维、醋酯纤维和纤维素纤维的逸出气红外谱图有很大的差异性,而涤纶、腈纶、锦纶66、锦纶6、丙纶、丝、毛和醋酯纤维更有各自的红外特征吸收峰,可互相区别并准确鉴定。不同纤维素纤维的逸出气红外谱图比较相似,但通过特征峰强度对比和热重曲线分析,可以将棉、苎麻、亚麻与粘胶、莫代尔、莱赛尔纤维进行区分。TG/FTIR检测技术无需对样品进行前处理、操作简便、干扰因素少、谱图的特征识别性好,在纤维成分快速鉴别中具有独特的优势。

优化血清蛋白醋酸纤维素薄膜电泳实验教学

在生物化学实验项目“血清蛋白醋酸纤维素薄膜电泳”教学中发现电泳结果往往不佳,山东农业大学生物化学教学团队通过不断地教学实践和吸收总结前人经验对此进行了一系列优化处理,包括血清样品的选择、电极缓冲液的使用、增加点样练习、电泳参数的设置、染色及漂洗等方面,最后得到了分离效果较好的电泳图谱,从而提高了生化实验教学质量,学生的理论知识和实验技能掌握更扎实,科技创新能力和综合素质都得到了提升。

Cellulose synthesis in land plants

All plant cells are surrounded by a cell wall that provides cohesion,protection,and a means of directional growth to plants.Cellulose microfibrils contribute the main biomechanical scaffold for most of these walls.The biosynthesis of cellulose,which typically is the most prominent constituent of the cell wall and therefore Earth’s most abundant biopolymer,is finely attuned to developmental and environmental cues.Our understanding of the machinery that catalyzes and regulates cellulose biosynthesis has substantially improved due to recent technological advances in,for example,structural biology and microscopy.Here,we provide a comprehensive overview of the structure,function,and regulation of the cellulose synthesis machinery and its regulatory interactors.We aim to highlight important knowledge gaps in the field,and outline emerging approaches that promise a means to close those gaps.

苹果酸脱氢酶协同纤维素酶水解纤维素:理论分析与实验

纤维素分子的刚性结构被认为是限制纤维素酶与底物接触的主要障碍,通过添加纤维素降解辅助蛋白破坏纤维素结构可以有效解决酶对底物的可及性问题。基于文献报道糖苷水解酶家族4(GH_(4))成员中α-葡萄糖苷酶对纤维素酶有协同作用,以及α-葡萄糖苷酶与苹果酸脱氢酶(MDH)的蛋白同源性和蛋白结构分析,本文提出MDH也具有协同作用的功能猜想,并开展了MDH协同纤维素酶水解滤纸纤维素的理论以及实验研究。通过分子对接模拟MDH与结晶纤维素的相互作用,理论分析发现MDH可能通过氢键和疏水的作用来降低纤维素的凝聚。实验考察了MDH添加量、纤维素酶量、水解时间等条件对MDH协同纤维素酶水解纤维素的影响。结果表明,在(50±0.50)mg滤纸体系中添加0.06FPU纤维素酶、150μg苹果酸脱氢酶,50℃水浴震荡24h,测定的还原糖产量是纤维素酶单独作用时的(3.47±0.28)倍,MDH对纤维素酶的增效活性为247%±28%。利用扫描电子显微镜(SEM)、X射线衍射(XRD)以及傅里叶变换红外光谱(FTIR)等手段对MDH作用前后的滤纸进行分析,所得结果表明MDH对纤维素的结晶区域具有破坏作用,协同促进了纤维素酶对纤维素的水解。作为一种有效的纤维素降解辅助蛋白,MDH为提高纤维素的酶法水解效率提供了更多选择。

羧甲基纤维素钠对挤压豌豆蛋白素肉品质的影响

为了提高豌豆蛋白素肉的表观品质,探究挤压过程中多糖与蛋白相互作用对素肉品质的影响,本研究采用高水分挤压法,制作羧甲基纤维素钠(carboxymethylcellulose sodium,CMC)与豌豆蛋白粉混合基素肉,分析CMC添加量(0%、2%、4%、6%、8%)对豌豆蛋白素肉的质构特性、色泽、微观结构和蛋白分子作用力的影响,以及素肉蛋白二级结构、分子作用力与表观结构(质构、色差)的相关性。结果表明,维持豌豆蛋白素肉结构的主要作用力是二硫键。与未添加CMC相比,添加量4%CMC通过促进豌豆蛋白素肉中二硫键的形成,将素肉的硬度提高了95%。同时,观察到豌豆蛋白素肉具有光滑完整的表面和均匀的结构。二级结构中的无规卷曲含量增加,促进明亮度增强,CMC改善了豌豆蛋白素肉的品质。

不同浓度大豆分离蛋白对壳聚糖-纳米纤维可食膜结构及性能的影响

多糖常被用于食品可降解包装材料。壳聚糖与纤维素纳米纤维作为可食膜基质具有较好防水性能,然而在机械性能及理化性质等方面有所不足。本试验将不同(0%,0.5%,1%,1.5%,2%)的大豆分离蛋白(SPI)与壳聚糖和纤维素纳米纤维混合制备可食膜,通过傅里叶红外光谱、X射线衍射、差示扫描量热法、扫描电子显微镜等方法研究可食膜的微观结构、静电作用以及对其性能的影响。结果表明,SPI与壳聚糖和纤维素纳米纤维主要以氢键以及静电相互作用为主,SPI添加量为1%时相互作用最强,网络结构致密,横截面变得更加光滑。在SPI添加量为1%时,可食膜的拉伸强度增至6.42 MPa,断裂伸长率增至97.47%,不透明度与接触角显著变大(P<0.05),水蒸气透过率和氧气透过率分别降至0.86 g·mm·m^(-2)·h^(-1)·kPa^(-1)和10.63 g·m^(-2)·d^(-1),吸水性能和溶解性能明显减弱。结论:加入1%的SPI可使可食膜的性能达到最优,试验结果为蛋白多糖可食膜的制备及应用提供理论参考。

茶渣纳晶纤维素的制备及其对大豆分离蛋白膜性能的影响

该研究以茶渣为原料,通过碱处理、漂白处理提取茶渣纤维素,采用硫酸水解法制备茶渣纳晶纤维素(tea residue nanocrystalline cellulose,TRNC),利用显微成像技术、傅里叶变换红外光谱、X-射线衍射仪、热重分析仪等技术对TRNC的微观形貌、化学官能团、晶体结构、热稳定性等理化性质进行表征。探究TRNC对大豆分离蛋白膜机械性能、水蒸气透过率和水溶性的影响。结果表明,TRNC呈典型的针状结构,Zeta电位值为(-32.76±2.11)mV,结晶度为62.36%。经TRNC强化的大豆分离蛋白膜,拉伸强度、水蒸气阻隔性能和耐水性能均有显著提升,而断裂伸长率有所下降。TRNC有潜力用作蛋白基可食膜的结构增强剂。

The CELLULOSE-SYNTHASE LIKE C （CSLC） Family of Barley Includes Members that Are Integral Membrane Proteins Targeted to the Plasma Membrane

The CELLULOSE SYNTHASE-LIKE C （CSLC） family is an ancient lineage within the CELLULOSE SYNTHASE/CELLULOSE SYNTHASE-LIKE （CESA/CSL） polysaccharide synthase superfamily that is thought to have arisen before the divergence of mosses and vascular plants. As studies in the flowering plant Arabidopsis have suggested synthesis of the （1,4）-β-glucan backbone of xyloglucan （XyG）, a wall polysaccharide that tethers adjacent cellulose microfibrils to each other, as a probable function for the CSLCs, CSLC function was investigated in barley （Hordeum vulgate L.）, a species with low amounts of XyG in its walls. Four barley CSLCgenes were identified （designated HvCSLC1-4）. Phylogenetic analysis reveals three well supported clades of CSLCs in flowering plants, with barley having representatives in two of these clades. The four barley CSLCs were expressed in various tissues, with in situ PCR detecting transcripts in all cell types of the coleoptile and root, including cells with primary and secondary cell walls. Co-expression analysis showed that HvCSLC3 was coordinately expressed with putative XyG xylosyltransferase genes. Both immuno-EM and membrane fractionation showed that HvCSLC2 was located in the plasma membrane of barley suspension-cultured cells and was not in internal membranes such as endoplasmic reticulum or Golgi apparatus. Based on our current knowledge of the sub-cellular locations of polysaccharide synthesis, we conclude that the CSLC family probably contains more than one type of polysaccharide synthase.

不同施氮量对饲用燕麦中蛋白质和纤维素的影响

[目的]探究氮肥施用水平对饲用燕麦品质的影响,确定饲用燕麦的最适施氮量范围。[方法]选用燕麦草为供试材料,设置0(N0)、175(N175)、200(N200)、225(N225)、250(N250)、275(N275)、300(N300)kg/hm2共7个氮肥施用梯度,在苗期、分蘖期、拔节期、抽穗期分别追施氮肥用量的15%、35%、30%、20%。采用大田小区下的单因素随机区组设计,每个区组设置3个重复,分别在拔节期和抽穗期测定0~10 cm、10~20 cm和20~30 cm土层土壤碱解氮含量以及饲用燕麦的蛋白质和纤维素含量。[结果]随着施氮水平的增加,土壤碱解氮含量升高,并出现积累的现象;与不施氮肥组相比,不同施氮水平下拔节期和抽穗期各土层的土壤碱解氮含量都有不同程度的提高。饲用燕麦的品质并不会随着可利用的氮素养分含量的增加而一直提高,存在峰值;施氮水平N225时,饲用燕麦在拔节期和抽穗期的蛋白质含量均达到最大值,分别为11.55%、16.13%,增幅分别为38.15%、53.62%。饲用燕麦的分蘖数在施氮水平N175时达到最大值(分蘖中位数=8);蛋白质和纤维素含量随施氮水平的增加呈先增加后降低的变化趋势,在施氮水平N225、N175时,蛋白质和纤维素含量分别达到最大值。[结论]在施氮水平N225~N275的范围内,饲用燕麦的蛋白质和纤维素含量达到协同最适值。

高涂布率轻质抹灰石膏的研制

通过研究建筑石膏种类、轻骨料种类、纤维素醚种类的选择,纤维素醚的黏度和用量,普硅水泥用量及缓凝剂用量等对轻质抹灰石膏的涂布率、抗压强度、拉伸粘结强度等性能的影响,确定了高涂布率轻质高强抹灰石膏的配比组成为:石膏粉88%~90%,普硅水泥2.0%~4.0%,轻骨料8.0%,掺黏度为50 000 m Pa·s的EH纤维素醚0.25%~0.35%,蛋白质类缓凝剂用量为0.015%~0.020%。制备的高涂布率轻质抹灰石膏施工顺滑,物理性能符合GB/T 28627—2023的技术要求。

Dual-functional bacterial cellulose modified with phase-transitioned proteins and gold nanorods combining antifouling and photothermal bactericidal properties

Bacterial cellulose(BC)is one of the most versatile natural biopolymers with unique physical,chemical,and biological features.However,the lack of intrinsic antibacterial property of native BC limits its broad biomedical applications where such property is highly required to prevent contamination or infection caused by attached bacteria.In this work,we developed a simple and facile method to fabricate a dualfunctional BC membrane by physical incorporation of gold nanorods(GNRs)followed by deposition of a phase-transitioned bovine serum albumin(PTB)film.Due to the broad-spectrum antifouling property of the PTB film,the resulting membrane could prevent the adhesion and accumulation of bacteria.A few bacteria that broke through the protection of the PTB film could be eradicated under short-term irradiation of a near-infrared laser due to the excellent photothermal property of incorporated GNRs.The whole fabrication was conducted in a simple and environmentally friendly manner,avoiding complicated processes and toxic organic solvents.Moreover,because all the components were biocompatible,the resulting membrane showed negligible cytotoxicity in vitro and good histocompatibility in vivo.This work thus provided a reliable way to endow BC with antibacterial property,being beneficial for diverse biomedical applications.