Academic literature on the topic 'Cellulose molecule'
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Journal articles on the topic "Cellulose molecule"
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Maji, Poulami, Megha Maji, Paramita Ghosh, and Prashant Shukla. "Cellulase-producing Microorganisms from Diverse Ecosystem: A Review." UTTAR PRADESH JOURNAL OF ZOOLOGY 46, no. 2 (2025): 25–38. https://doi.org/10.56557/upjoz/2025/v46i24760.
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Cellulose is the most abundant organic matter present on the planet. It is made up of glucose molecules which is the ultimate energy currency. Still, cellulose is utilized by most the animals as energy source as they lack necessary enzymes for degradation of the molecule. The animals who are able to utilize cellulose based materials as source of energy are able to do so due to cellulase producing gut microflora. Cellulases are enzymes which are used by certain organisms to breakdown the cellulose. Very small number of organisms are able to produce different types of cellulases which can break the bonds present in cellulose molecules. Only few bacteria, fungi and protozoa have necessary genes for cellulase. It has been found that certain herbivorous insects are also able to synthesize their own cellulase but again this property is very limited in few insect types. The microorganisms who are able to synthesize cellulase are present in soil and water along with certain mammalian and insect guts. In soil and water such microorganisms decompose the dead plant matter containing cellulose and help in maintaining the carbon cycle along with getting energy from the molecule. Apart from ecological activity the cellulases are utilized for various industrial purposes. In the current review we have discussed different types of microorganisms which are able to produce cellulases. The source of such microorganisms are also discussed briefly to place them in the right context.
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LIAO, RUIJIN, MENGZHAO ZHU, XIN ZHOU, et al. "MOLECULAR DYNAMICS STUDY OF THE DISRUPTION OF H-BONDS BY WATER MOLECULES AND ITS DIFFUSION BEHAVIOR IN AMORPHOUS CELLULOSE." Modern Physics Letters B 26, no. 14 (2012): 1250088. http://dx.doi.org/10.1142/s0217984912500881.
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Hydrolysis is an important component of the aging of cellulose, and it severely affects the insulating performance of cellulosic materials. The diffusion behavior of water molecules in amorphous cellulose and their destructive effect on the hydrogen bonding structure of cellulose were investigated by molecular dynamics. The change in the hydrogen bonding structure indicates that water molecules have a considerable effect on the hydrogen bonding structure within cellulose: both intermolecular and intramolecular hydrogen bonds decreased with an increase in ingressive water molecules. Moreover, the stabilities of the cellulose molecules were disrupted when the number of intermolecular hydrogen bonds declined to a certain degree. Both the free volumes of amorphous cells and water molecule-cellulose interaction affect the diffusion of water molecules. The latter, especially the hydrogen bonding interaction between water molecules and cellulose, plays a predominant role in the diffusion behavior of water molecules in the models of which the free volume rarely varies. The diffusion coefficient of water molecules has an excellent correlation with water molecule-cellulose interaction and the average hydrogen bonds between each water molecule and cellulose; however, this relationship was not apparent between the diffusion coefficient and free volume.
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Celik, Sefa, A. Demet Demirag, Aysen E. Ozel, and Sevim Akyuz. "Molecular Structure, vibrational spectra, Molecular Docking and ADMET Study of Cellulose Triacetate II-=SUP=-*-=/SUP=-." Журнал технической физики 128, no. 8 (2020): 1128. http://dx.doi.org/10.21883/os.2020.08.49709.194-19.
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People have started to look for alternative sources because of the health problems created by petrochemical products used in all areas of human life and environmental problems that remain intact in nature for years. In this study, molecular structure analysis of cellulose triacetate II (CTA II) molecule, obtained from cellulose II and acetate, was carried out. There is an important relationship between the structure and activity of molecules, so it is very important to determine the geometric structure of a molecule. Therefore, using density functional theory (DFT) the most stable molecular geometries of the cellulose triacetate II monomer (C12H18O9) as well as dimer (C24H36O18), which included intermolecular H-bonding, were calculated. The analogous calculations were carried out for the (CTA-II)2 nano-cluster (C24H34O17), which represents the local structure of CTA-II crystal, and created by binding the two most stable CTA II molecules by covalent bond. Scaled wavenumbers and potential energy distribution of the vibrational modes of CTA monomer and (CTA-II)2 nano-cluster were computed. In order to evaluate the interaction of CTA II with the Aspergillus niger cellulase enzyme,which is an important that is active in cellulose digestion and CTA II, molecular docking studies were carried out. H-binding interactions between CTA II (in monomeric, dimeric and cluster forms) and the active site of the Aspergillus niger cellulase enzyme were shown. Moreover, in silico ADMET prediction study was calculated for CTA-II monomer to predict its druglikeness properties. Keywords: Cellulose triacetate II, Density Function Theory, IR-ATR, cluster for.
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Li, Ke, Huiyu Yang, Lang Jiang, et al. "Glycerin/NaOH Aqueous Solution as a Green Solvent System for Dissolution of Cellulose." Polymers 12, no. 8 (2020): 1735. http://dx.doi.org/10.3390/polym12081735.
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Dissolving cellulose in water-based green solvent systems is highly desired for further industrial applications. The green solvent glycerin—which contains hydrogen-bonding acceptors—was used together with NaOH and water to dissolve cellulose. This mixed aqueous solution of NaOH and glycerin was employed as the new green solvent system for three celluloses with different degree of polymerization. FTIR (Fourier-transform infrared), XRD (X-ray diffractometer) and TGA (thermogravimetric analysis) were used to characterize the difference between cellulose before and after regenerated by HCl. A UbbeloHde viscometer was used to measure the molecule weight of three different kinds of cellulose with the polymerization degree of 550, 600 and 1120. This solvent system is useful to dissolve cellulose with averaged molecule weight up to 2.08 × 105 g/mol.
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Petkun, Svetlana, Sadanari Jindou, Linda J. W. Shimon, et al. "Structure of a family 3b′ carbohydrate-binding module from the Cel9V glycoside hydrolase fromClostridium thermocellum: structural diversity and implications for carbohydrate binding." Acta Crystallographica Section D Biological Crystallography 66, no. 1 (2009): 33–43. http://dx.doi.org/10.1107/s0907444909043030.
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Family 3 carbohydrate-binding modules (CBM3s) are associated with both cellulosomal scaffoldins and family 9 glycoside hydrolases (GH9s), which are multi-modular enzymes that act on cellulosic substrates. CBM3s bind cellulose. X-ray crystal structures of these modules have established an accepted cellulose-binding mechanism based on stacking interactions between the sugar rings of cellulose and a planar array of aromatic residues located on the CBM3 surface. These planar-strip residues are generally highly conserved, although some CBM3 sequences lack one or more of these residues. In particular, CBM3b′ fromClostridium thermocellumCel9V exhibits such sequence changes and fails to bind cellulosic substrates. A crystallographic investigation of CBM3b′ has been initiated in order to understand the structural reason(s) for this inability. CBM3b′ crystallized in space groupC2221(diffraction was obtained to 2.0 Å resolution in-house) with three independent molecules in the asymmetric unit and in space groupP41212 (diffraction was obtained to 1.79 Å resolution in-house and to 1.30 Å resolution at a synchrotron) with one molecule in the asymmetric unit. The molecular structure of Cel9V CBM3b′ revealed that in addition to the loss of several cellulose-binding residues in the planar strip, changes in the backbone create a surface `hump' which could interfere with the formation of cellulose–protein surface interactions and thus prevent binding to crystalline cellulose.
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Pachernegg-Mair, Lukas, Jana Bianca Schaubeder, Carina Waldner, et al. "Probing interfacial interactions: Ionic liquids and cellulose thin films." Probing interfacial interactions: Ionic liquids and cellulose thin films 356 (March 26, 2025): 123356. https://doi.org/10.1016/j.carbpol.2025.123356.
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The efficient processing of cellulosic materials with ionic liquids heavily relies on the initial contact and wetting phase, which are crucial yet poorly understood in many ionic liquid/cellulose interactions. In this study, we explore these interactions through comprehensive wetting experiments and a robust mathematical framework. By leveraging molecular-kinetic theory (MKT), we illuminate the key factors affecting these interactions, such as viscosity and ion pair volume, and identify specific cellulose chain groups involved in the process. Our findings confirm that ionic liquids selectively adsorb on active sites of cellulose, facilitating a dynamic adsorption-desorption mechanism crucial for forward movement. Notably, we have identified these adsorption sites to be approximately 5 to 20 Å apart, e.g., distances between neighboring C<sub>6</sub>-hydroxyl groups within a cellulose molecule. Furthermore, our results demonstrate that the dynamics of jump frequencies are intrinsically linked to the properties of ionic liquids, yet influenced by a complex array of parameters. This study provides significant insights into manipulating the interaction mechanisms to enhance spreading efficiency on surfaces. Our research underscores the pivotal role of cellulose's chemical structure and order, offering valuable implications for improving high-throughput processing techniques in various industrial applications.
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GARSOUX, Geneviève, Josette LAMOTTE, Charles GERDAY, and Georges FELLER. "Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis." Biochemical Journal 384, no. 2 (2004): 247–53. http://dx.doi.org/10.1042/bj20040325.
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The cold-adapted cellulase CelG has been purified from the culture supernatant of the Antarctic bacterium Pseudoalteromonas haloplanktis and the gene coding for this enzyme has been cloned, sequenced and expressed in Escherichia coli. This cellulase is composed of three structurally and functionally distinct regions: an N-terminal catalytic domain belonging to glycosidase family 5 and a C-terminal cellulose-binding domain belonging to carbohydrate-binding module family 5. The linker of 107 residues connecting both domains is one of the longest found in cellulases, and optimizes substrate accessibility to the catalytic domain by drastically increasing the surface of cellulose available to a bound enzyme molecule. The psychrophilic enzyme is closely related to the cellulase Cel5 from Erwinia chrysanthemi. Both kcat and kcat/Km values at 4 °C for the psychrophilic cellulase are similar to the values for Cel5 at 30–35 °C, suggesting temperature adaptation of the kinetic parameters. The thermodynamic parameters of activation of CelG suggest a heat-labile, relatively disordered active site with low substrate affinity, in agreement with the experimental data. The structure of CelG has been constructed by homology modelling with a molecule of cellotetraose docked into the active site. No structural alteration related to cold-activity can be found in the catalytic cleft, whereas several structural factors in the overall structure can explain the weak thermal stability, suggesting that the loss of stability provides the required active-site mobility at low temperatures.
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Jiang, Xuewei, Wei Wang, Yuanyuan Guo, and Min Dai. "Molecular Dynamics Simulation of the Effect of Low Temperature on the Properties of Lignocellulosic Amorphous Region." Forests 14, no. 6 (2023): 1208. http://dx.doi.org/10.3390/f14061208.
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In this paper, a molecular model of cellulose amorphous region-water molecule was developed using Materials Studio software by applying the molecular dynamics method. The effect of low temperature on the properties of the lignocellulosic amorphous region, the main component of wood, was investigated in an attempt to explain the macroscopic property changes from a microscopic perspective and to provide a theoretical basis for the safe use of wood and wood products in low-temperature environments and other related areas of research. Dynamic simulations were carried out at 20 °C, 0 °C, −30 °C, −70 °C, −110 °C and −150 °C for the NPT combinations to obtain the energy, volume, density, and hydrogen bonding change trends of their models, respectively. The changes in the microstructure of the water molecule–cellulose amorphous region model were analyzed, and the mechanical properties were calculated. The results showed that the interaction between the amorphous cellulose region and water molecules was enhanced as the temperature decreased, the density of the models increased, and the volume decreased. The number of total hydrogen bonds and the number of hydrogen bonds between water molecule–cellulose chains increased for each model, and the decrease in temperature made the cellulose molecular activities weaker. The values of G, E, and K increased with the decrease in temperature, and K/G decreased with the decrease in temperature. It shows that the decrease in temperature is beneficial to enhance the mechanical properties of the amorphous region of cellulose and increases the stiffness of the material. However, the toughness and plasticity decrease when the temperature is too low.
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Jung, Jaemyeong, Tiziano Gaiotto, Hau B. Nguyen, et al. "A Molecular View of Cellulase-Catalyzed Hydrolysis of Cellulose: A Single Molecule Approach." Biophysical Journal 102, no. 3 (2012): 271a—272a. http://dx.doi.org/10.1016/j.bpj.2011.11.1496.
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Divya, Supratim Mahapatra, Vinish Ranjan Srivastava, and Pranjal Chandra. "Nanobioengineered Sensing Technologies Based on Cellulose Matrices for Detection of Small Molecules, Macromolecules, and Cells." Biosensors 11, no. 6 (2021): 168. http://dx.doi.org/10.3390/bios11060168.
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Recent advancement has been accomplished in the field of biosensors through the modification of cellulose as a nano-engineered matrix material. To date, various techniques have been reported to develop cellulose-based matrices for fabricating different types of biosensors. Trends of involving cellulosic materials in paper-based multiplexing devices and microfluidic analytical technologies have increased because of their disposable, portable, biodegradable properties and cost-effectiveness. Cellulose also has potential in the development of cytosensors because of its various unique properties including biocompatibility. Such cellulose-based sensing devices are also being commercialized for various biomedical diagnostics in recent years and have also been considered as a method of choice in clinical laboratories and personalized diagnosis. In this paper, we have discussed the engineering aspects of cellulose-based sensors that have been reported where such matrices have been used to develop various analytical modules for the detection of small molecules, metal ions, macromolecules, and cells present in a diverse range of samples. Additionally, the developed cellulose-based biosensors and related analytical devices have been comprehensively described in tables with details of the sensing molecule, readout system, sensor configuration, response time, real sample, and their analytical performances.
Dissertations / Theses on the topic "Cellulose molecule"
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O'Sullivan, Antoinette C. "Modelling of cellulose-molecule interactions." Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296178.
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Liu, Jianzhao. "Studies of Macromolecule/Molecule Adsorption and Activity at Interfaces." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/104041.
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Interfaces are ubiquitous in our daily life. A good understanding of the interfacial properties between different materials, or a single material in different physical states is of critical importance for us to explore the current world and bring benefits to mankind. In this work, interfacial behavior was investigated with the help of surface analysis techniques, such as quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR) and atomic force microscopy (AFM), in order to gain better understanding on biofuel conversion, gene/drug delivery, and chemical fixation of CO2.
Biomimetic chelator-mediated Fenton (CMF) non-enzymatic degradations on cellulose and chitin thin films was studied by liquid-phase QCM-D and AFM. QCM-D is a powerful tool to monitor the kinetics of hydrolysis of regenerated cellulose and chitin model surfaces. Results from QCM-D and AFM showed that the majority of the biomass of the two model surfaces can be hydrolyzed by the CMF system. The initial degradation rates for both model surfaces by the CMF system are faster than that of the corresponding enzyme systems. The CMF system, which is a good non-enzymatic pretreatment agent for cellulose and chitin, may work on a wide variety of polysaccharide systems.
Adsorption of cationic cellulose derivatives onto self-assembled monolayer (SAM) surfaces was investigated using liquid-phase SPR. Results from SPR showed that depending upon the cellulose derivative structure, irreversible adsorption ranging from a monolayer to ~1.6 layers of cellulose derivative were formed on the SAM-COOH surface based upon a charge neutralization mechanism. At low salt concentrations, the long-range electrostatic attraction between the cationic cellulose derivatives (6-PyrCA and 6-MeIMCA) and the SAM surfaces facilitates the formation of a 2-dimensional monolayer. While, for TMACE, the energy gained through the hydrophobic interaction between adjacent long polyelectrolyte branches may afford the electrostatic repulsion and chain entropy penalties, resulting in the formation of 3-dimensional adsorbed polyelectrolyte layers.
Adsorption of 1,2-epoxybutane gas molecules onto/into VPI-100 metal–organic frameworks (MOFs) was studied by gas-phase QCM-D experiments. Results from QCM-D demonstrated that VPI-100 (Ni) MOFs have higher irreversible adsorption per unit cell (θ) and faster diffusion coefficients (D) than VPI-100 (Cu) MOFs. The presence of bound counter-balancing ions on the metallo-cyclam core was attributed as the cause of the higher θ and faster D through the Ni analogue, which suggests the MOF-epoxide interaction occurs at the metallo-cyclam. This study shed light upon tuning MOF structures for better CO2 sorption and epoxide activation to gain higher catalytic efficiency.
Finally, in operando high energy X-ray diffraction (HEXRD) was used to monitor the phase transition of the NaxNi1/3Co1/3Mn1/3O2 cathode material during the sintering process. The first charge/discharge cycle of the NaxNi1/3Co1/3Mn1/3O2 cathode materials in different phases were also studied by in operando HEXRD. It was found that the intergrowth P2/O1/O3 cathode (NCM-Q cathode) can inhibit the irreversible P2–O2 phase transition and simultaneously improve the structural stability of the O3 and O1 phases during cycling. The NCM-Q cathode with triple-phase integration demonstrates highly reversible phase evolution during high voltage cycling, possibly leading to a highly reversible capacity and good cycle stability.<br>Doctor of Philosophy<br>Interfaces and surfaces are everywhere. Many critical processes, such as molecular recognition, catalysis, and charge transfer, take place at interfaces. The surfaces of plants and animals provide barriers from pathogens, prevent damage from mechanical impacts, detect external stimuli, etc. Inside the human body, nutrition and oxygen are adsorbed through interactions between substances and cell surfaces. Investigations of interfacial behaviors may help us understand our current world better and bring benefits to mankind. In this dissertation, the interface between bio-renewable natural polymers and biomimetic chelators, the interface between a self-assembled monolayer and cationic cellulose derivatives, and the interface between metal–organic frameworks (MOF) and 1,2-epoxybutane gas molecules, were studied with a quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR) and atomic force microscopy (AFM), to gain insights into biofuel conversion, gene/drug delivery and chemical fixation of CO2, respectively. Additionally, thermally and electrochemically induced phase transitions in sodium-ion battery (SIB) cathode materials were probed via in operando high energy X-ray diffraction (HEXRD).
Biomimetic chelator-mediated Fenton (CMF) non-enzymatic degradations of cellulose and chitin thin films were studied by liquid-phase QCM-D and AFM. It was found that the majority of the biomass of the two model surfaces can be degraded by the CMF system. Adsorption of cationic cellulose derivatives onto self-assembled monolayer (SAM) surfaces was investigated using liquid-phase SPR. It was found that both the absorbed layer conformation and the absorbed amount depend upon the interplay between long-range electrostatic interactions and short-range interactions. Adsorption of 1,2-epoxybutane gas molecules onto/into VPI-100 MOFs was studied by gas-phase QCM-D experiments. Data from QCM-D revealed the irreversible gas molecule absorption onto/into MOFs and shed light upon tuning MOF structures for better CO2 sorption and epoxide activation to gain higher catalytic efficiency. Finally, the in operando high energy X-ray diffraction (HEXRD) was used to probe thermally and electrochemically induced phase transitions in sodium-ion battery (SIB) cathode materials. It was found that the NCM-Q cathode with triple-phase integration demonstrates highly reversible phase evolution during high voltage cycling, possibly leading to a highly reversible capacity and good cycle stability.
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Ferreira, Luis Manuel dos Anjos. "Molecular analysis of cellulases and xylanses from Pseudomonas fluorescens subspecies cellulosa." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316083.
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Ubhayasekera, Wimal. "Structural studies of cellulose and chitin active enzymes /." Uppsala : Dept. of Molecular Biology, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200518.pdf.
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Adams, Katherine Victoria. "Dyeing of cellulosic fibres : how the structure of cellulose and the dye molecules affect the dyeing process." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621863.
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Ihara, Yuri. "Molecular analysis of cotton cellulose synthase." Kyoto University, 2002. http://hdl.handle.net/2433/149921.
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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第9635号<br>農博第1263号<br>新制||農||845(附属図書館)<br>学位論文||H14||N3667(農学部図書室)<br>UT51-2002-G393<br>京都大学大学院農学研究科応用生命科学専攻<br>(主査)教授 酒井 富久美, 教授 關谷 次郎, 教授 島田 幹夫<br>学位規則第4条第1項該当
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Vedel, Jean. "Cellules de Langerhans humaines et molécules d'adhésion." Bordeaux 2, 1990. http://www.theses.fr/1990BOR23108.
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Prates, Erica Teixeira 1985. "Dinâmica molecular de hidrolases para sacarificação : de celulose e proteínas correlatas." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248862.
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Previous issue date: 2013<br>Resumo: A biomassa lignocelulósica proveniente do bagaço de cana-de-açúcar e de outras matérias-primas é um material altamente promissor para a geração de biocombustíveis renováveis e ambientalmente positivos. A melhor opção para a conversão dessa biomassa em açúcares solúveis fermentáveis a etanol, em termos de rendimento e de vantagens ambientais, é a catálise enzimática. Mas esta é também a etapa mais cara do processo de obtenção de etanol de segunda geração devido à baixa eficiência e alto custo dos coquetéis enzimáticos atualmente disponíveis para este fim. Para tornar estes processos mais eficientes e economicamente viáveis, é preciso aprofundar nossa compreensão dos mecanismos de hidrólise celulolítica. Grande investimento em pesquisa tem sido empregado com esta finalidade e, como parte disto, este trabalho consiste em um conjunto de pesquisas desenvolvidas na área de simulação computacional via dinâmica molecular de três enzimas celulolíticas: 1) Laminarinase de Rodhothermus marinus; 2) Endoglucanase 3 de Trichoderma harzianum e 3) b- glicosidase de Aspergillus niger. De modo geral, estes estudos visaram investigar a relação entre o arranjo estrutural e propriedades mensuráveis em laboratório interessantes na avaliação da performance destes biocatalisadores, como afinidade pelo substrato e estabilidade térmica. Como parte do Projeto Temático BioEn, financiado pela FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo), estes estudos computacionais foram realizados em estreita colaboração com grupos de biofísicos estruturais e biólogos moleculares, sendo a escolha dos três temas embasada em resultados experimentais<br>Abstract: The lignocellulosic biomass from sugar cane bagasse and from other raw materials is a highly promising material for the generation of renewable and environmentally positive fuels. In terms of performance and environmental advantages, the best option for converting this biomass into soluble sugars to produce ethanol is the enzymatic catalysis. However, this is also the most expensive step of the second-generation ethanol production due to the low efficiency and high cost of the currently available enzyme cocktails. In order to make the process more efficient and economically viable, it is necessary to deepen the understanding of the cellulolytic hydrolysis mechanisms. Great investment in research has been employed for this purpose, and as part of these efforts, this work consists on a set of molecular dynamics studies of three cellulolytic enzymes, namely: 1) laminarinase from Rodhothermus marinus; 2) Endoglucanase 3 from Trichoderma harzianum and 3) b-glucosidase from Aspergillus niger. In general, these studies aimed to investigate the relationship between the structural arrangement and experimental data that are interesting for the biocatalyst performance evaluation, such as affinity to the substrate and thermal stability. As part of the BioEn Thematic Project, funded by FAPESP (Research Foundation of the State of São Paulo), these computational studies were carried out in close collaboration with structural biophysicists and molecular biologists. The choice of the three proteins considered here was based on these experimental studies<br>Doutorado<br>Físico-Química<br>Doutora em Ciências
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Adams, K. V. "Dyeing of cellulose fibres : how the structure of cellulose and the dye molecules affect the dyeing process." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595346.
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The understanding of the dyeing of cellulosic fibres has been limited by the lack of fundamental knowledge about the structures and processes that occur on the molecular scale. The work reported in this dissertation has begun to address some of the areas where greater insight into these structures and processes is required. This information can then be used as input into existing empirical models of the dyeing process used in industry. The solid state structure of various cellulosic fibres were investigated using carbon-13 cross polarisation/magic angle spinning nuclear magnetic resonance (<SUP>13</SUP>C CP/MAS NMR) spectroscopy. The percentage crystallinities and the proportions of the different crystalline forms of cellulose, Iα, Iβ and II, in each sample were calculated from lineshape analyses of the spectra. The presence of cellulose II in mercerised cotton was confirmed and it is proposed that the degree of mercerisation is indicated by the percentage crystallinity and the proportion of cellulose II present in the sample. The pulsed-gradient spin-echo (PGSE) NMR technique has been used to characterise the self-diffusion of water within various cellulose samples. A new model, defined by a three-component diffusivity, has been proposed to describe this diffusion and it is consistent with the known structures of various cellulosic fibres, such as native cotton and Tencel. It is also proposed that some of the variations in dyeability of cellulose fibres might be partially explained by the observed differences in the self-diffusion of water within the samples. The characterisation of the self-diffusion and aggregation of acid dyes in aqueous solution has been investigated for the first time using the PGSE NMR method. The results found agree well with the literature, and the main trends, such as an increase in the average aggregation number caused by a corresponding increase in dye molecular weight, dye concentration or addition of NaCl, were observable by this method. Finally, the self-diffusion of dye molecules within cotton fibres was investigated using the PGSE NMR technique. Not all dyes could be studied using this method as it was found that an increase in the affinity of the dye for the cotton fibre surface caused the dye molecules to be associated with fast relaxation times and therefore become 'invisible' to the NMR experiment. Major variations were apparent when comparing the diffusion of dye within the unmercerised and mercerised cotton. It is proposed that this difference is found because of the increased affinity of dyes towards the surface of mercerised cotton.
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Barretto, de Menezes Alexandre. "Molecular ecology of cellulose-degrading microorganisms in freshwater lakes." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511074.
Full textBooks on the topic "Cellulose molecule"
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Kamide, Kenji. Cellulose and cellulose derivatives: Molecular characterization & its applications. Elsevier, 2005.
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Brown, R. Malcolm, and Inder M. Saxena, eds. Cellulose: Molecular and Structural Biology. Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-5380-1.
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Gough, Clare Linda. Molecular genetics of cellulase production by "Xanthomonas campestris". University of EastAnglia, 1989.
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J, Murphy Martin, and Kuter David J, eds. Thrombopoietin: From molecule to medicine. AlphaMed Press, 1998.
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Flyvbjerg, F., F. Jülicher, P. Ormos, and F. David, eds. Physics of bio-molecules and cells. Physique des biomolécules et des cellules. Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-45701-1.
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Bray, Dennis. Cell movements: From molecules to motility. 2nd ed. Garland Pub., 2001.
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Saloheimo, Anu. Yeast Saccharomyces cerevisiae as a tool in cloning and analysis of fungal genes: Applications for biomass hydrolysis and utilisation. VTT Technical Research Centre of Finland, 2004.
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Eleanor, Lawrence. A guide to modern biology: Genetics, cells, and systems. Longman Scientific & Technical, 1989.
Find full textBook chapters on the topic "Cellulose molecule"
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Liu, Yu-San, Shi-You Ding, and Michael E. Himmel. "Single-Molecule Tracking of Carbohydrate-Binding Modules on Cellulose Using Fluorescence Microscopy." In Methods in Molecular Biology. Humana Press, 2012. http://dx.doi.org/10.1007/978-1-61779-956-3_13.
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Sfiligoj Smole, Majda, Silvo Hribernik, Manja Kurečič, Andreja Urbanek Krajnc, Tatjana Kreže, and Karin Stana Kleinschek. "Cellulose Nanofibres." In SpringerBriefs in Molecular Science. Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-10407-8_5.
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Miyamoto, Hitomi, Keita Sakakibara, Isao Wataoka, Yoshinobu Tsujii, Chihiro Yamane, and Kanji Kajiwara. "Interaction of Water Molecules with Carboxyalkyl Cellulose." In Cellulose Science and Technology. John Wiley & Sons, Inc., 2018. http://dx.doi.org/10.1002/9781119217619.ch6.
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French, Alfred D., and Glenn P. Johnson. "Cellulose Shapes." In Cellulose: Molecular and Structural Biology. Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-5380-1_15.
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Zhang, Y. H. Percival, Jiong Hong, and Xinhao Ye. "Cellulase Assays." In Methods in Molecular Biology. Humana Press, 2009. http://dx.doi.org/10.1007/978-1-60761-214-8_14.
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Arioli, Tony, Joanne E. Burn, and Richard E. Williamson. "Molecular Biology of Cellulose Biosynthesis." In Molecular Biology of Woody Plants. Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-2311-4_8.
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Nishinari, K., K. Kohyama, N. Shibuya, et al. "Molecular Motions in Cellulose Derivatives." In Viscoelasticity of Biomaterials. American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0489.ch024.
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Nobles, David R., and R. Malcolm Brown. "Many Paths up the Mountain: Tracking the Evolution of Cellulose Biosynthesis." In Cellulose: Molecular and Structural Biology. Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-5380-1_1.
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Saxena, Inder M., and R. Malcolm Brown. "A Perspective on the Assembly of Cellulose-Synthesizing Complexes: Possible Role of KORRIGAN and Microtubules in Cellulose Synthesis in Plants." In Cellulose: Molecular and Structural Biology. Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-5380-1_10.
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Emons, Anne Mie, Miriam Akkerman, Michel Ebskamp, Jan Schel, and Bela Mulder. "How Cellulose Synthase Density in the Plasma Membrane may Dictate Cell Wall Texture." In Cellulose: Molecular and Structural Biology. Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-5380-1_11.
Full textConference papers on the topic "Cellulose molecule"
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Liu, Yu-San, Yonghua Luo, John O. Baker, et al. "A single molecule study of cellulase hydrolysis of crystalline cellulose." In BiOS, edited by Jörg Enderlein, Zygmunt K. Gryczynski, and Rainer Erdmann. SPIE, 2010. http://dx.doi.org/10.1117/12.840975.
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Cremer, Gilles, Vera Van Hoed, Sabine Danthine, Anne Dombree, Anne-Sophie Laveaux, and Christophe Blecker. "New Insight in the Structure-properties Relationship of Hydroxypropyl Cellulose." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/anuw8263.
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Hydroxypropyl cellulose (HPC) is a semi-synthetic polymer that results from the hydroxypropylation of hydroxyl groups of the repeating glucose units that form the cellulose backbone. The grafting of hydroxypropyl substituents provides the molecule with good surface properties. The resulting water-soluble polymer has many applications, mainly in the pharmaceutical and food industries. Due to the flexibility of its manufacturing process, HPC can be obtained in different commercial grades, each characterized by its molecular weight and viscosity. It has already been reported in the past that differences in functionality can occur even between theoretically similar products. Some research groups had already drawn attention to the fact that compendial specifications provided by suppliers were too broad to allow an accurate description of the molecular state of the HPC. This results in some cases in the impossibility to guarantee the same functionality even for products of the same grade. This work studied different HPC of the same commercial grades and provides new insights into the influence of the structure on the techno-functional properties of HPC. Surface properties, rheology, and thermal behavior have been studied. Different complementary surface tension analysis methods were used to determine the surface properties. Equilibrium surface tension of 0.2% w:w HPC aqueous solutions varied from 40-44 mN/m (20°C). Differences in viscosity and cloud point were also observed. Nuclear Magnetic Resonance allowed to determine the degree of substitution and gain information about structure, which were later related to the differences in properties. The results show that the degrees of substitution and the heterogeneity of distribution of substituents along the polymer chain have a great impact on surface-properties, rheological, and thermal behavior of the samples. These results have great significance for applications in emulsions and foams.
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Birtane, Hatice, and Aslı Beyler Çiğil. "Edible film production with aloe vera extract and its printability." In 11th International Symposium on Graphic Engineering and Design. University of Novi Sad, Faculty of technical sciences, Department of graphic engineering and design, 2022. http://dx.doi.org/10.24867/grid-2022-p47.
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The main concern with protecting fruits and vegetables from bacterial infection and growth is ensuring product quality and safety. Hydroxyethyl cellulose, with –OH in the natural cellulose molecule substituted by a hydroxyethyl group, has been widely used in oil exploitation, coating, medicine, food and polymerization process. It is nontoxic and low-cost. Aloe vera is a well-known herbal plant that is used for its therapeutic properties. The gel extracted from Aloe vera plants contains a variety of biologically active compounds, phenolic contents, and minerals. In this study, the edible films containing different proportions of aloe vera and hydroxyl ethyl cellulose were prepared. The structural and antibacterial properties of the obtained edible films were examined. The obtained films were printed with inkjet. Color and adhesion properties of printed samples were determined and it was observed that the edible films showed antibacterial properties.
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Oh, Kyudeok, Minwoo Lee, Hye Jung Youn, Dae Hong Jeong, and Hak Lae Lee. "Paper-based Chemical Detecting Sensors for Surface-enhanced Raman Scattering." In Advances in Pulp and Paper Research, Oxford 2017, edited by W. Batchelor and D. Söderberg. Fundamental Research Committee (FRC), Manchester, 2017. http://dx.doi.org/10.15376/frc.2017.2.751.
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In this study, we fabricated a paper-based molecule-detecting sensor for the surface-enhanced Raman scattering (SERS) technique. SERS phenomenon is based on the face that the low intensity of Raman scattering is dramatically increased when the molecules are adsorbed on novel metal surface. To improve the applicability of paper substrate as a base for SERS several trials were made. The smoothness of the filter paper was improved through a calendaring process. To prevent the spreading of the chemical solution on the aper the hydrophobicity of paper was increased by treating with an alkyl ketene dimer (AKD). Onto the smooth and hydrophobic filter paper a silver nanoparticle (AgNP) solution was applied with a simple drop and dry method, and analyte was treated in the same manner on the AgNP decorated area for SERS measurement. To improve the reproducibility of the SERS intensity, an area scanning method that used a dual axis galvanometric mirror was introduced. A 4-aminothiophenol molecule could be detected at the femtomolar level using the hydrophobic-treated filter paper. Coating of cellulose nanofibrils (CNF) made from pulp fibers reduced the surface pore sizes and increased the uniformity of the surface of the filter paper, which improved the reproducibility and sensitivity of the molecule-detecting sensor. The use of a high magnification objective lens for increased SERS intensity allowed for the detection of a strong SERS signal, and the application of a CNF coating to the filter paper improved the reproducibility. Pesticides were detected using the paper-based substrate as SERS substrate.
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Song, Bo, Ning Xi, Ruiguo Yang, Zhiyong Sun, and Liangliang Chen. "In situ visualization of dynamic interactions of cellulase and cellulose molecules." In 2014 IEEE 14th International Conference on Nanotechnology (IEEE-NANO). IEEE, 2014. http://dx.doi.org/10.1109/nano.2014.6968134.
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Atalla, Rajai H. "Studies of Polymorphy in Native Cellulose." In Papermaking Raw Materials, edited by V. Punton. Fundamental Research Committee (FRC), Manchester, 1985. http://dx.doi.org/10.15376/frc.1985.1.59.
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Our studies of cellulose structure based on X-ray diffractometry, Raman spectroscopy, and Solid State ¹³C-NMR have led us to a model which addresses questions of structure at two levels. The first is that of the organization of individual chains. Two stable ordered states of cellulose chains are postulated, together with a disordered state in which there is less coherence between the orientations of adjacent anhydroglucose rings. The ordered states are identified as kᵢ and kᵢᵢ based on their predominance in celluloses I and II, respectively; both conformations are based on the dimeric anhydrocellobiose as the basic repeat until in the ordered chain. The disordered state is identified as kₒ. The second level of organization is that of aggregation of chains into three-dimensionally ordered crystalline domains. At this level our model recognizes two crystalline forms within the native state. These are identified as Iα and Iß, the first found to be dominant in bacterial and algal celluloses, the second dominant in celluloses from higher plants. These two forms are found to contain chains possessing the same molecular conformation ᵏI, but the patterns of hydrogen bonding are found to be different. Cellulose II, which is derived from the native state by mercerization or regeneration at low temperatures, is found to consist predominantly of chains in the ᵏII conformation in yet a third distinct crystalline lattice.
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Isogai, Akira, та Lars A. Berglund. "Review: Preparation and Applications of Nanofibrillar Celluloses". У Advances in Pulp and Paper Research, Cambridge 2013, редактор S. J. I’ Anson. Fundamental Research Committee (FRC), Manchester, 2013. http://dx.doi.org/10.15376/frc.2013.2.737.
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Nanofibrillar celluloses are promising new bio-based nanomaterials that can be prepared from paper- grade chemical pulps and other plant celluloses by mechanical shearing in water, usually after pretreatments. For example, enzymatic hydrolysis, carboxymethylation, addition of cationic polymers, TEMPO-mediated oxidation and others have been applied as wood cellulose pretreatments to reduce the energy consumption of the mechanical shearing process and to improve nanofibrillation level. Nanofibrillated celluloses (NFCs) prepared from wood cellulose by either enzymatic hydrolysis or partial carboxymethylation and subsequent mechanical shearing in water are convertible to nanopaper films and aerogels using a filtration process like that used in papermaking, which is advantageous for efficient removal of water from the strongly swollen NFC/water dispersions. NFCs have high molecular weights and long fibrils and form fibril network structures both in aqueous dispersions and dried nanopaper films/aerogels. This makes them preferable for use as base materials for nanocomposites. Thus, various nanopaper/matrix composites have been prepared, some of which show remarkably high mechanical strength including high ductility. When TEMPO- mediated oxidation is used as the pretreatment, almost completely individualized TEMPO-oxidized cellulose nanofibrils (TOCNs) with homogeneous widths of ~3 nm dispersed in water can be prepared from oxidized wood celluloses with carboxylate contents >1.2 mmol/g by gentle mechanical disintegration treatment. Because TOCN elements form nematic-ordered structures due to their self- assembling behavior in water, TOCNs are able to be converted to dense films with plywood- like layered structures, stiff hydrogels by acid treatment, aerogels with extremely high specific surface areas, and other unique bulk materials. When TOCNs are used to make nanocomposite materials, high mechanical strengths and gas- barrier properties can be achieved even with low TOCN-loading ratios.
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Denman, Stuart, Ulla Rudsander, Henrik Aspeborg, Peter Nilsson, and Tuula T. Teeri. "MOLECULAR MODELLING SUGGESTS A MODIFIED SUBSTRATE-BINDING SITE IN CELLULASES INVOLVED IN CELLULOSE BIOSYNTHESIS." In XXIst International Carbohydrate Symposium 2002. TheScientificWorld Ltd, 2002. http://dx.doi.org/10.1100/tsw.2002.415.
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Aspler, J. S., N. Chauret, and M. B. Lyne. "Mechanism of Self-Sizing of Paper." In Papermaking Raw Materials, edited by V. Punton. Fundamental Research Committee (FRC), Manchester, 1985. http://dx.doi.org/10.15376/frc.1985.2.707.
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Investigations on the self-sizing of a pure cellulose paper show that surfactant acts to prevent self-sizing by solubilizing fatty acid molecules and forming a physical barrier to chemical bond formation between cellulose and fatty acid molecules. The acceleration of self-sizing by alum has a mechanism similar to that of conventional rosin-alum sizing: the formation and polymerization of aluminum soaps on the fibre surface. It is suggested that the reaction between cellulose hydroxyl groups and aluminum soaps, as proposed in the literature, is not likely. Instead, material that is not solvent-extractable is either extensively polymerized or reacted with residual carboxyl groups on the fibre surface.
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Wang, Ying, and Youping Chen. "An Atomic Model of Cellulose Network in Wood Cell Wall." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67603.
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Wood is composed of parallel columns of long hollow cells which are made up of layered composite of semi-crystalline cellulose fibrils embedded in an amorphous matrix of hemicellulose and lignin. The extraordinary mechanical performance of wood is believed to result from a molecular mechanism operated through hydrogen bond connection. However, the molecular interactions, the assembly method of cell-wall components, as well as the molecular mechanisms responsible for the deformation of wood, are not well understood yet. Progress in studying the superior mechanical properties of wood cell is severely hindered because of this fact. To overcome this barrier, the foremost step is to build up an atomic model of the native cellulose fibril network, which is the dominant polysaccharide in wood cell walls. Then, in this work, we proposed the atomic models to study the cellulose network which includes a single cellulose microfibril (MF), and a thin film which is built up by first secondary layers (S1) and second secondary layers (S2) composed of cellulose MF with periodic boundary conditions. Additionally, we investigated the length effect of the microfibril and compared the effect of explicit water solvent environment with the vacuum environment. Moreover, the spatial arrangements of these atomic models have been determined by molecular mechanics simulation (energy minimization). The hydrogen bond length of the crystalline part of the inner cellulose was evaluated using first principle calculation.
Reports on the topic "Cellulose molecule"
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Morrison, Mark, and Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, 2000. http://dx.doi.org/10.32747/2000.7695844.bard.
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At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.
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Walker, Larry P. ,. Bergstrom, Gary, Stephane Corgie, Harold Craighead, Donna Gibson, and David Wilson. Addressing the Recalcitrance of Cellulose Degradation through Cellulase Discovery, Nano-scale Elucidation of Molecular Mechanisms, and Kinetic Modeling. Office of Scientific and Technical Information (OSTI), 2011. http://dx.doi.org/10.2172/1016086.
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Morrison, Mark, Joshuah Miron, Edward A. Bayer, and Raphael Lamed. Molecular Analysis of Cellulosome Organization in Ruminococcus Albus and Fibrobacter Intestinalis for Optimization of Fiber Digestibility in Ruminants. United States Department of Agriculture, 2004. http://dx.doi.org/10.32747/2004.7586475.bard.
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Improving plant cell wall (fiber) degradation remains one of the highest priority research goals for all ruminant enterprises dependent on forages, hay, silage, or other fibrous byproducts as energy sources, because it governs the provision of energy-yielding nutrients to the host animal. Although the predominant species of microbes responsible for ruminal fiber degradation are culturable, the enzymology and genetics underpinning the process are poorly defined. In that context, there were two broad objectives for this proposal. The first objective was to identify the key cellulosomal components in Ruminococcus albus and to characterize their structural features as well as regulation of their expression, in response to polysaccharides and (or) P AA/PPA. The second objective was to evaluate the similarities in the structure and architecture of cellulosomal components between R. albus and other ruminal and non-ruminal cellulolytic bacteria. The cooperation among the investigators resulted in the identification of two glycoside hydrolases rate-limiting to cellulose degradation by Ruminococcus albus (Cel48A and CeI9B) and our demonstration that these enzymes possess a novel modular architecture specific to this bacterium (Devillard et al. 2004). We have now shown that the novel X-domains in Cel48A and Cel9B represent a new type of carbohydrate binding module, and the enzymes are not part of a ceiluiosome-like complex (CBM37, Xu et al. 2004). Both Cel48A and Cel9B are conditionally expressed in response to P AA/PPA, explaining why cellulose degradation in this bacterium is affected by the availability of these compounds, but additional studies have shown for the first time that neither PAA nor PPA influence xylan degradation by R. albus (Reveneau et al. 2003). Additionally, the R. albus genome sequencing project, led by the PI. Morrison, has supported our identification of many dockerin containing proteins. However, the identification of gene(s) encoding a scaffoldin has been more elusive, and recombinant proteins encoding candidate cohesin modules are now being used in Israel to verify the existence of dockerin-cohesin interactions and cellulosome production by R. albus. The Israeli partners have also conducted virtually all of the studies specific to the second Objective of the proposal. Comparative blotting studies have been conducted using specific antibodies prepare against purified recombinant cohesins and X-domains, derived from cellulosomal scaffoldins of R. flavefaciens 17, a Clostridium thermocellum mutant-preabsorbed antibody preparation, or against CbpC (fimbrial protein) of R. albus 8. The data also suggest that additional cellulolytic bacteria including Fibrobacter succinogenes S85, F. intestinalis DR7 and Butyrivibrio fibrisolvens Dl may also employ cellulosomal modules similar to those of R. flavefaciens 17. Collectively, our work during the grant period has shown that R. albus and other ruminal bacteria employ several novel mechanisms for their adhesion to plant surfaces, and produce both cellulosomal and non-cellulosomal forms of glycoside hydrolases underpinning plant fiber degradation. These improvements in our mechanistic understanding of bacterial adhesion and enzyme regulation now offers the potential to: i) optimize ruminal and hindgut conditions by dietary additives to maximize fiber degradation (e.g. by the addition of select enzymes or PAA/PPA); ii) identify plant-borne influences on adhesion and fiber-degradation, which might be overcome (or improved) by conventional breeding or transgenic plant technologies and; iii) engineer or select microbes with improved adhesion capabilities, cellulosome assembly and fiber degradation. The potential benefits associated with this research proposal are likely to be realized in the medium term (5-10 years).
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Karnchanatat, Aphichart. Fibrinolytic enzyme from Sand Warm Perinereis nuntia. Chulalongkorn University, 2013. https://doi.org/10.58837/chula.res.2013.106.
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A protease from sandworms (Perinereis nuntia) was purified by using a combination of ammonium sulfate precipitation, DEAE cellulose and Superdex-200, respectively. The enriched preparation had a specific activity of 355.74 U/mg proteins and a yield of 18.5% total protein. The molecular weight of this protease was estimated to be 37.4 kDa by SDS-15% (w/v) PAGE. The pH stability of this protease is between pH 7-8, and it is stable up to 40 °C. The activity of the enzyme was inhibited by Cu2+ and Co2+, but was enhanced by Ca2+ and Mg2+ ions. Furthermore, protease activity was potently inhibited by EDTA.
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Blanton, R. L. A molecular genetic approach to understanding eukaryotic cellulose synthesis. Final technical report, March 15, 1995--March 14, 1997. Office of Scientific and Technical Information (OSTI), 1997. http://dx.doi.org/10.2172/548677.
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Shomer, Ilan, Ruth E. Stark, Victor Gaba, and James D. Batteas. Understanding the hardening syndrome of potato (Solanum tuberosum L.) tuber tissue to eliminate textural defects in fresh and fresh-peeled/cut products. United States Department of Agriculture, 2002. http://dx.doi.org/10.32747/2002.7587238.bard.
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The project sought to understand factors and mechanisms involved in the hardening of potato tubers. This syndrome inhibits heat softening due to intercellular adhesion (ICA) strengthening, compromising the marketing of industrially processed potatoes, particularly fresh peeled-cut or frozen tubers. However, ICA strengthening occurs under conditions which are inconsistent with the current ideas that relate it to Ca-pectate following pectin methyl esterase (PME) activity or to formation of rhamnogalacturonan (RG)-II-borate. First, it was necessary to induce strengthening of the middle lamellar complex (MLX) and the ICA as a stress response in some plant parenchyma. As normally this syndrome does not occur uniformly enough to study it, we devised an efficient model in which ICA-strengthening is induced consistently under simulated stress by short-chain, linear, mono-carboxylic acid molecules (OAM), at 65 oC [appendix 1 (Shomer&Kaaber, 2006)]. This rapid strengthening was insufficient for allowing the involved agents assembly to be identifiable; but it enabled us to develop an efficient in vitro system on potato tuber parenchyma slices at 25 ºC for 7 days, whereas unified stress was reliably simulated by OAMs in all the tissue cells. Such consistent ICA-strengthening in vitro was found to be induced according to the unique physicochemical features of each OAM as related to its lipophilicity (Ko/w), pKa, protonated proportion, and carbon chain length by the following parameters: OAM dissociation constant (Kdiss), adsorption affinity constant (KA), number of adsorbed OAMs required for ICA response (cooperativity factor) and the water-induced ICA (ICAwater). Notably, ICA-strengthening is accompanied by cell sap leakage, reflecting cell membrane rupture. In vitro, stress simulation by OAMs at pH<pKa facilitated the consistent assembly of ICAstrengthening agents, which we were able to characterize for the first time at the molecular level within purified insoluble cell wall of ICA-strengthened tissue. (a) With solid-state NMR, we established the chemical structure and covalent binding to cell walls of suberin-like agents associated exclusively with ICA strengthening [appendix 3 (Yu et al., 2006)]; (b) Using proteomics, 8 isoforms of cell wall-bound patatin (a soluble vacuolar 42-kDa protein) were identified exclusively in ICA-strengthened tissue; (c) With light/electron microscopy, ultrastructural characterization, histochemistry and immunolabeling, we co-localized patatin and pectin in the primary cell wall and prominently in the MLX; (d) determination of cell wall composition (pectin, neutral sugars, Ca-pectate) yielded similar results in both controls and ICA-strengthened tissue, implicating factors other than PME activity, Ca2+ or borate ions; (e) X-ray powder diffraction experiments revealed that the cellulose crystallinity in the cell wall is masked by pectin and neutral sugars (mainly galactan), whereas heat or enzymatic pectin degradation exposed the crystalline cellulose structure. Thus, we found that exclusively in ICA-strengthened tissue, heat-resistant pectin is evident in the presence of patatin and suberinlike agents, where the cellulose crystallinity was more hidden than in fresh control tissue. Conclusions: Stress response ICA-strengthening is simulated consistently by OAMs at pH< pKa, although PME and formation of Ca-pectate and RG-II-borate are inhibited. By contrast, at pH>pKa and particularly at pH 7, ICA-strengthening is mostly inhibited, although PME activity and formation of Ca-pectate or RG-II-borate are known to be facilitated. We found that upon stress, vacuolar patatin is released with cell sap leakage, allowing the patatin to associate with the pectin in both the primary cell wall and the MLX. The stress response also includes formation of covalently bound suberin-like polyesters within the insoluble cell wall. The experiments validated the hypotheses, thus led to a novel picture of the structural and molecular alterations responsible for the textural behavior of potato tuber. These findings represent a breakthrough towards understanding of the hardening syndrome, laying the groundwork for potato-handling strategies that assure textural quality of industrially processed particularly in fresh peeled cut tubers, ready-to-prepare and frozen preserved products.
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Manulis, Shulamit, Christine D. Smart, Isaac Barash, Guido Sessa, and Harvey C. Hoch. Molecular Interactions of Clavibacter michiganensis subsp. michiganensis with Tomato. United States Department of Agriculture, 2011. http://dx.doi.org/10.32747/2011.7697113.bard.
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Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato plants are largely unknown. The goal of the project was to elucidate the molecular interactions between Cmmand tomato. The first objective was to analyze gene expression profiles of susceptible tomato plants infected with pathogenic and endophytic Cmmstrains. Microarray analysis identified 122 genes that were differentially expressed during early stages of infection. Cmm activated typical basal defense responses in the host including induction of defense-related genes, production of scavenging of free oxygen radicals, enhanced protein turnover and hormone synthesis. Proteomic investigation of the Cmm-tomato interaction was performed with Multi-Dimensional Protein Identification Technology (MudPIT) and mass spectroscopy. A wide range of enzymes secreted by Cmm382, including cell-wall degrading enzymes and a large group of serine proteases from different families were identified in the xylem sap of infected tomato. Based on proteomic results, the expression pattern of selected bacterial virulence genes and plant defense genes were examined by qRT-PCR. Expression of the plasmid-borne cellulase (celA), serine protease (pat-1) and serine proteases residing on the chp/tomA pathogenicity island (chpCandppaA), were significantly induced within 96 hr after inoculation. Transcription of chromosomal genes involved in cell wall degradation (i.e., pelA1, celB, xysA and xysB) was also induced in early infection stages. The second objective was to identify by VIGS technology host genes affecting Cmm multiplication and appearance of disease symptoms in plant. VIGS screening showed that out of 160 tomato genes, which could be involved in defense-related signaling, suppression of 14 genes led to increase host susceptibility. Noteworthy are the genes Snakin-2 (inhibitor of Cmm growth) and extensin-like protein (ELP) involved in cell wall fortification. To further test the significance of Snakin -2 and ELP in resistance towards Cmm, transgenic tomato plants over-expressing the two genes were generated. These plants showed partial resistance to Cmm resulting in a significant delay of the wilt symptoms and reduction in size of canker lesion compared to control. Furthermore, colonization of the transgenic plants was significantly lower. The third objective was to assess the involvement of ethylene (ET), jasmonate (JA) and salicylic acid (SA) in Cmm infection. Microarray and proteomic studies showed the induction of enzymes involved in ET and JA biosynthesis. Cmm promoted ET production 8 days after inoculation and SIACO, a key enzyme of ET biosynthesis, was upregulated. Inoculation of the tomato mutants Never ripe (Nr) impaired in ET perception and transgenic plants with reduced ET synthesis significantly delayed wilt symptoms as compared to the wild-type plants. The retarded wilting in Nr plants was shown to be a specific effect of ET insensitivity and was not due to altered expression of defense related genes, reduced bacterial population or decrease in ethylene biosynthesis . In contrast, infection of various tomato mutants impaired in JA biosynthesis (e.g., def1, acx1) and JA insensitive mutant (jai1) yielded unequivocal results. The fourth objective was to determine the role of cell wall degrading enzymes produced by Cmm in xylem colonization and symptoms development. A significance increase (2 to 7 fold) in expression of cellulases (CelA, CelB), pectate lyases (PelA1, PelA2), polygalacturonase and xylanases (XylA, XylB) was detected by qRT-PCR and by proteomic analysis of the xylem sap. However, with the exception of CelA, whose inactivation led to reduced wilt symptoms, inactivation of any of the other cell wall degrading enzymes did not lead to reduced virulence. Results achieved emphasized the complexity involved in Cmm-tomato interactions. Nevertheless they provide the basis for additional research which will unravel the mechanism of Cmm pathogenicity and formulating disease control measures.
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Carpita, Nicholas C., Ruth Ben-Arie, and Amnon Lers. Pectin Cross-Linking Dynamics and Wall Softening during Fruit Ripening. United States Department of Agriculture, 2002. http://dx.doi.org/10.32747/2002.7585197.bard.
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Our study was designed to elucidate the chemical determinants of pectin cross-linking in developing fruits of apple and peach and to evaluate the role of breakage cross-linkages in swelling, softening, and cell separation during the ripening. Peaches cell walls soften and swell considerably during the ripening, whereas apples fruit cells maintain wall firmness but cells separate during late stages of ripening. We used a "double-reduction" technique to show that levels of non-methyl esters of polyuronic acid molecules were constant during the development and ripening and decreased only in overripe fruit. In peach, methyl and non-methyl esters increased during the development and decreased markedly during the ripening. Non-methyl ester linkages in both fruit decreased accompanied fruit softening. The identity of the second component of the linkage and its definitive role in the fruit softening remain elusive. In preliminary examination of isolated apples cell walls, we found that phenolic compounds accumulate early in wall development but decrease markedly during ripening. Quantitative texture analysis was used to correlate with changes to wall chemistry from the fresh-picked ripe stage to the stage during storage when the cell separation occurs. Cell wall composition is similar in all cultivars, with arabinose as the principal neutral sugar. Extensive de-branching of these highly branched arabinans pre-stages softening and cell-cell separation during over-ripening of apple. The longer 5-arabinans remain attached to the major pectic polymer rhamnogalacturonan I (RG I) backbone. The degree of RG I branching, as judged from the ratios of 2-Rha:2,4-Rha, also decreases, specially after an extensive arabinan de-branching. Loss of the 4-Rham linkages correlated strongly with the softening of the fruit. Loss of the monomer or polymer linked to the RG I produce directly or indirectly the softening of the fruit. This result will help to understand the fruit softening and to have better control of the textural changes in fruit during the ripening and especially during the storage. 'Wooliness', an undesirable mealy texture that is induced during chilling of some peach cultivars, greatly reduces the fruit storage possibilities. In order to examine the hypothesis that the basis for this disorder is related to abnormality in the cell wall softening process we have carried out a comparative analysis using the resistant cultivar, Sunsnow, and a sensitive one, Hermosa. We investigated the activity of several pectin- and glycan-modifying enzymes and the expression of their genes during ripening, chilling, and subsequent shelf-life. The changes in carbohydrate status and in methyl vs. non-methyl uronate ester levels in the walls of these cultivars were examined as well to provide a basis for comparison of the relevant gene expression that may impact appearance of the wooly character. The activities of the specific polygalacturonase (PGase) and a CMC-cellulase activities are significantly elevated in walls of peaches that have become wooly. Cellulase activities correlated well with increased level of the transcript, but differential expression of PGase did not correspond with the observed pattern of mRNA accumulation. When expression of ethylene biosynthesis related genes was followed no significant differences in ACC synthase gene expression was observed in the wooly fruit while the normal activation of the ACC oxidase was partially repressed in the Hermosa wooly fruits. Normal ripening-related loss of the uronic acid-rich polymers was stalled in the wooly Hermosa inconsistent with the observed elevation in a specific PGase activity but consistent with PG gene expression. In general, analysis of the level of total esterification, degree of methyl esterification and level of non-methyl esters did not reveal any major alterations between the different fruit varieties or between normal and abnormal ripening. Some decrease in the level of uronic acids methyl esterification was observed for both Hermosa and Sunsnow undergoing ripening following storage at low temperature but not in fruits ripening after harvest. Our results support a role for imbalanced cell wall degradation as a basis for the chilling disorder. While these results do not support a role for the imbalance between PG and pectin methyl esterase (PME) activities as the basis for the disorder they suggest a possible role for imbalance between cellulose and other cell wall polymer degradation during the softening process.
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Supercomputer Provides Molecular Insight into Cellulose (Fact Sheet). Office of Scientific and Technical Information (OSTI), 2011. http://dx.doi.org/10.2172/1009253.
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