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Structure of cellulose. Three parallel chains which form the 0,1,0 face are shown, and a glucose moiety and repeating cellobiose unit are indicated. The model was built by Dr. José Tormo, based on early crystallographic data. The diagram was drawn using RasMol 2.6.
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This work increases our understanding of the effect of plant source on the mechanical and morphological properties of lignin-based polyurethanes (PUs). Lignin is a polymer that is synthesized inside the plant cell wall and can be used as a polyol to synthesize PUs. The specific aromatic structure of the lignin is heavily reliant on the plant source...
Citations
... Поскольку в основе клеточной стенки растений лежат общеизвестные полисахариды [113][114][115][116] Эволюционная нелинейная химия... Деревообработка и химическая переработка древесины выполнять свою функцию вне контакта с целлюлозой (в частности, это касается функции механических тканей), любое исследование формирования жидкокристаллических систем на основе нативной целлюлозы является частным случаем исследования жидкокристаллических свойств не только целлюлозы, но и всех полисахаридов клеточной стенки (особенно, учитывая, что без предобработки не представляется возможным отделить некоторые из них от других). Исходя из ультраструктурных механизмов, разделение исследований по «естественным жидким кристаллам» на основе целлюлозы и их лабораторным эквивалентам с точки зрения морфометрии и геометрии соответствующих структур (мезофаз, их прекурсоров и депо локализации) обусловлено наличием компартментализации в биологических источниках целлюлозы (например, так называемые «целлюлосомы» -класс внеклеточных органелл/компартментов, в которых происходит переработка и деградация полисахаридов, включая целлюлозу [120]) и их отсутствием в тех безмембранных условиях, в которых формируются жидкокристаллические и мезофазные полисахариды в лаборатории. ...
Gradov O.V. [Evolutionary nonlinear chemistry of self-organizing mesophase (liquid crystal) structures of wood: from morphogenesis to regulation of carbon formation (review)]. Lesnoy vestnik / Forestry Bulletin, 2023, vol. 27, no. 3, pp. 91–127. DOI: 10.18698/2542-1468-2023-3-91-127 - This work reconstructs the transformation stages of the mesophase (liquid crystal) wood components from their native state to the processes of coke and coal formation. The phytochemical precursors of mesophases (from lignin and polysaccharides, such as cellulose, to lipids) differing in their cell localization are considered separately. Several criteria are listed by which the similarity between the processes of mesophase formation based on the plant raw materials during carbon formation and self-organization in such systems (including the processes proceeding under the thermal pumping) is observed. The role of membrane and membrane-mimetic interfaces in regulation of the above processes is indicated. The applicability of biogeochemical redox criteria (anaerobic, subaerial, aerobic modes) in the analysis of mesophase diagenesis is considered. It is postulated that, due to the specific regulation/ feedback, the above factors can lead to the spatial heterogeneity during coal formation, «autocatalytic» effects and the emergence of redox oscillations, accompanied by the localized changes in the properties of mesophases - from those supporting combustion to practically fire retardant. Based on the dependence of the main properties of the corresponding products on the processes of their production and / or formation, as well as their (geo) chemical environment (which is characteristic of supramolecular and colloidal chemistry), it is possible to formulate supramolecular and colloidal chemical approaches to the interpretation of a number of phenomena and mechanisms of the biogenic fossil mesophase formation, which requires consideration in a separate review paper.
... Исходя из ультраструктурных механизмов, разделение исследований по «естественным жидким кристаллам» на основе целлюлозы и их лабораторным эквивалентам, с точки зрения морфо-/геометрии соответствующих структур -мезофаз, прекурсоров мезофаз и депо локализации -обусловлено наличием компартментализации в биологических источниках целлюлозы (например, т.н. «целлюлосомы» -класс внеклеточных органелл / компартментов, в которых происходит переработка и деградация полисахаридов, включая целлюлозу [120]) и их отсутствием в тех безмембранных условиях, в которых формируются жидкокристаллические и мезофазные полисахариды в лаборатории. ...
... However, the final cell biomass of FAs1 and GAs1 was still lower than that of CGs1, in contrast to the results obtained in the work of Johnson et al. [29], who found that the final H. thermocellum cell density of FAs1, GAs1 and CGs1 was comparable. As the most powerful hydrolytic machinery that has been identified in a microorganism to date, H. thermocellum cellulosomal function, composition, and regulation patterns have been a popular research topic for decades [1][2][3][4]7,12,14,17,18,25,26,28,29,43,[49][50][51][52][53][54][55][56][57]. Regarding cellulosomal enzyme activities, FAs1 cellulosomes expressed the highest exoglucanase, endoglucanase, and xylanase activities, followed by CGs1 cellulosomes ( Figure 2B). ...
Hungateiclostridium thermocellum ATCC 27405 is a promising bacterium for consolidated bioprocessing with a robust ability to degrade lignocellulosic biomass through a multienzyme cel-lulosomal complex. The bacterium uses the released cellodextrins, glucose polymers of different lengths, as its primary carbon source and energy. In contrast, the bacterium exhibits poor growth on monosaccharides such as fructose and glucose. This phenomenon raises many important questions concerning its glycolytic pathways and sugar transport systems. Until now, the detailed mechanisms of H. thermocellum adaptation to growth on hexose sugars have been relatively poorly explored. In this study, adaptive laboratory evolution was applied to train the bacterium in hexose sugars-based media, and genome resequencing was used to detect the genes that got mutated during adaptation period. RNA-seq data of the first culture growing on either fructose or glucose revealed that several glycolytic genes in the Embden-Mayerhof-Parnas pathway were expressed at lower levels in these cells than in cellobiose-grown cells. After seven consecutive transfer events on fructose and glucose (~42 generations for fructose-adapted cells and ~40 generations for glucose-adapted cells), several genes in the EMP glycolysis of the evolved strains increased the levels of mRNA expression, accompanied by a faster growth, a greater biomass yield, a higher ethanol titer than those in their parent strains. Genomic screening also revealed several mutation events in the genomes of the evolved strains, especially in those responsible for sugar transport and central carbon metabolism. Consequently, these genes could be applied as potential targets for further metabolic engineering to improve this bacterium for bio-industrial usage.
... However, the final cell biomass of FAs1 and GAs1 was still lower than that of CGs1, in contrast to the results obtained in the work of Johnson et al. [29], who found that the final H. thermocellum cell density of FAs1, GAs1 and CGs1 was comparable. As the most powerful hydrolytic machinery that has been identified in a microorganism to date, H. thermocellum cellulosomal function, composition, and regulation patterns have been a popular research topic for decades [1][2][3][4]7,12,14,17,18,25,26,28,29,43,[49][50][51][52][53][54][55][56][57]. Regarding cellulosomal enzyme activities, FAs1 cellulosomes expressed the highest exoglucanase, endoglucanase, and xylanase activities, followed by CGs1 cellulosomes ( Figure 2B). ...
Hungateiclostridium thermocellum ATCC 27405 is a promising bacterium with a robust ability to degrade lignocellulosic biomass complexes, including crystalline cellulose components, through a multienzyme cellulosomal system. In contrast, it exhibits poor growth on simple monosaccharides such as fructose and glucose. This phenomenon raises many important questions concerning its glycolytic pathways and sugar transport systems. Until now, the detailed mechanisms of H. thermocellum adaptation to growth on monosaccharides have been poorly explored. In this study, adaptive laboratory evolution was applied to train the bacterium on monosaccharides, and genome resequencing was used to detect the genes that had mutated during adaptation. RNA-seq data of the 1st-generation culture growing on either fructose or glucose revealed that several glycolytic genes in the EMP pathway were expressed at lower levels in these cells than in cellobiose-grown cells. After 8 generations of culture on fructose and glucose, the evolved H. thermocellum strains grew faster and yielded greater biomass than the nonadapted strains. Genomic screening also revealed several mutation events in the genomes of the evolved strains, especially in genes responsible for sugar transport and central carbon metabolism. Consequently, these genes could be applied as targets for further metabolic engineering to improve this bacterium for bioindustrial usage.
... In contrast, most, but not all, of the cohesin-dockerin interactions of the mesophilic clostridia appear to share the same general recognition residues, which may indicate general cross-species interaction of their scaffoldins and enzyme subunits in nature, and would imply their coexistence in the same ecological niche. In any case, evolutionary forces have not proved fit to change them during speciation processes [5,63]. Unlike the majority of the mesophilic clostridia, however, distinct alternative recognition residues are evident in C. saccharoperbutylacetonicum and C. bornimense. ...
The bacterial cellulosome is an extracellular, multi-enzyme machinery, which efficiently depolymerizes plant biomass by degrading plant cell wall polysaccharides. Several cellulolytic bacteria have evolved various elaborate modular architectures of active cellulosomes. We present here a genome-wide analysis of a dozen mesophilic clostridia species, including both well-studied and yet-undescribed cellulosome-producing bacteria. We first report here, the presence of cellulosomal elements, thus expanding our knowledge regarding the prevalence of the cellulosomal paradigm in nature. We explored the genomic organization of key cellulosome components by comparing the cellulosomal gene clusters in each bacterial species, and the conserved sequence features of the specific cellulosomal modules (cohesins and dockerins), on the background of their phylogenetic relationship. Additionally, we performed comparative analyses of the species-specific repertoire of carbohydrate-degrading enzymes for each of the clostridial species, and classified each cellulosomal enzyme into a specific CAZy family, thus indicating their putative enzymatic activity (e.g., cellulases, hemicellulases, and pectinases). Our work provides, for this large group of bacteria, a broad overview of the blueprints of their multi-component cellulosomal complexes. The high similarity of their scaffoldin clusters and dockerin-based recognition residues suggests a common ancestor, and/or extensive horizontal gene transfer, and potential cross-species recognition. In addition, the sporadic spatial organization of the numerous dockerin-containing genes in several of the genomes, suggests the importance of the cellulosome paradigm in the given bacterial species. The information gained in this work may be utilized directly or developed further by genetically engineering and optimizing designer cellulosome systems for enhanced biotechnological biomass deconstruction and biofuel production.
... In C. thermocellum, the intricacy of cellulosome assembly is further augmented by the complexity of some of its enzymes. Some of the cellulosomal enzymes are unusually large and contain numerous modules, and several contain more than one catalytic module (20,21,(93)(94)(95). The ∼180-kDa C. thermocellum CelJ, for example, contains six modules, including a GH9 and GH44 (96,97); and CelH (∼100 kDa) bears a GH5 and a GH26. ...
IntroductionPlant Cell Wall Structure and ChemistryPretreatment of BiomassEnzyme Components for Biomass DeconstructionEnzyme SystemsFuture Approaches for Agricultural Biomass DeconstructionConclusions
AcknowledgmentsReferences
... The family-9 glycoside hydrolases are cellulosomal and noncellulosomal cellulases that characterize numerous bacterial species, fungi, slime molds, plants, insects and molluscs (Coutinho & Henrissat, 1999; Henrissat & Davies, 2000; Bourne & Henrissat, 2001). The GH9s have been temporarily classified in one of four 'themes', which reflect their modular architecture (Ding et al., 1999; Bayer et al., 2000a, b; Gilad et al., 2003). One of these architectural themes (Theme B) is characterized by a GH9 catalytic module followed downstream by a family-3c carbohydrate-binding module (CBM3c). ...
We have sequenced a new gene, cel9B, encoding a family-9 cellulase from a cellulosome-producing bacterium, Acetivibrio cellulolyticus. The gene includes a signal peptide, a family-9 glycoside hydrolases (GH9) catalytic module, two family-3 carbohydrate-binding modules (CBM3c-CBM3b tandem dyad) and a C-terminal dockerin module. An identical modular arrangement exists in two putative GH9 genes from the draft sequence of the Clostridium thermocellum genome. The three homologous CBM3b modules from A. cellulolyticus and C. thermocellum were overexpressed, but, surprisingly, none bound cellulosic substrates. The results raise fundamental questions concerning the possible role(s) of the newly described CBMs. Phylogenetic analysis and preliminary site-directed mutagenesis studies suggest that the catalytic module and the CBM3 dyad are distinctive in their sequences and are proposed to constitute a new GH9 architectural theme.
... Cellulosomal components from Clostridium thermocellum. Compared to the cellulosomal Scaffoldin systems of C. cellulovorans and C. cellulolyticum, the enzymes from C. thermocellum are relatively large proteins, ranging in molecular size from about 40-180 kDa (Bayer et al., 1998;Bayer et al., 2000;Béguin and Lemaire, 1996;Felix and Ljungdahl, 1993;Lamed and Bayer, 1988;Shoham et al., 1999). Examination of Fig. 22 reveals why these enzymes are so big-many of the larger ones contain multiple types of catalytic domains as well as other functional modules as an integral part of a single polypeptide chain (see Table I in Bayer et al., 1998, for a list of relevant references). ...
Cellulose and associated polysaccharides, such as xylans, comprise the major portion of the plant cell wall as structural polymers. As the plants evolved and distributed first in the seas and then on land, following their demise, the accumulated cellulosic materials had to be assimilated and returned to nature. Thus the cellulose-degrading bacteria have evolved to complement lignin-degrading microbial systems for the purpose of restoring the tremendous quantities of organic components of the plant cell wall to the environment for continued life cycles of carbon and energy on the global scale. This chapter is a sequel to a previous chapter of the same title from the second edition of this treatise (Coughlan MP, Mayer F (1992) The cellulose-decomposing bacteria and their enzyme systems. In: Balows A, Trüper HG, Dworkin M, Harder W, Schleifer K-H (eds) The prokaryotes, vol I, 2nd edn. Springer, New York, pp 459-516.) and represents an update of our own subsequent chapter (Bayer EA, Shoham Y, Lamed R (2006) Cellulose-decomposing prokaryotes and their enzyme systems. In: Dworkin M, Falkow S, Rosenberg E, Schleifer K-H, Stackebrandt E (eds) The prokaryotes, vol 2, 3rd edn. Springer, New York, pp 578-617.) which appeared in the third edition. Although the basic elements of the previous chapters are still essentially up to date, the field of the cellulose-decomposing bacteria has since advanced greatly, owing to two major factors: (1) the advent, progression, and increasing facility of genome- and metagenome-sequencing efforts and (2) the current initiatives to utilize plant-derived biomass for the production of biofuels as an alternative to fossil fuels for an energy source. © 2013 Springer-Verlag Berlin Heidelberg. All rights are reserved.
... From these results the conclusion was drawn that the acid phosphatase of B. pseudomallei is a glycoprotein tyrosine phosphatase, located at the cell surface and that the complex nature of enzymatic activity may reflect the evolutionary stage of the enzyme (194). One of the best examples for surface-associated prokaryotic glycoproteins is the cellulosome complex of Clostridium thermocellum which contains, in addition to the major polypeptide scaffolding, a number of glycosylated and nonglycosylated enzymes (for review see196,197). Since this multimodular enzyme complex has been described in a number of recent reviews, it is not discussed here (for review see16-18, 196, 197). ...
A large number of proteins and lipids in biological systems are glycosylated. Comparisons of well characterized protein sequence data base entries indicate that more than half of all proteins in nature will eventually be identified as glycoproteins. Only recently, the importance of carbohydrates in biology has been more fully appreciated. With the introduction of molecular genetics, simplification of expression methods, and improvement of analytical techniques, a rapid expansion of the field of glycobiology has taken place, particularly in the domain of eukaryotic organisms. For an in-depth review of the structure, function and molecular biology of eukaryotic glycoproteins, the reader is referred to a number of recent reviews and monographs (1-9).
The world of gastrointestinal (GI) bacteria is one of the most complex and intricate of the microbial domain. These bacteria are confronted with a constantly changing (and often hostile) environment, including fluctuations in both physical and chemical conditions. Neighboring microorganisms not only contend for substrate but even launch complex chemical attacks with the apparent purpose of disrupting the activity of their competitors. Yet, some species not only survive, they even flourish, in the GI tract because they possess the ability to adapt to these environmental fluctuations and assaults from other microbes. Such adaptation involves sophisticated programs in the bacterial cell that enable it to monitor its environment and make necessary adjustments of physiological activity and gene expression. Among these adjustments is the ability of cell-to-cell communication, biofilm formation, regulation of cytoplasmic pH, and maintenance of genetic diversity through mutation and horizontal gene transfer. As a consequence, bacteria in the GI tract often manifest very different physiological features than are observed for the same bacteria during routine laboratory cultivation.
