scholarly journals Water-accessibility of interfibrillar spaces in spruce wood cell walls

Cellulose ◽  
2021 ◽  
Author(s):  
Paavo A. Penttilä ◽  
Aleksi Zitting ◽  
Tainise Lourençon ◽  
Michael Altgen ◽  
Ralf Schweins ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Cell Walls ◽  
Cellulose Microfibrils ◽  
Plant Cell Walls ◽  
Deuterated Water ◽  
Water Accessibility ◽  
Significant Difference ◽  
Nanoscale Structure ◽  
Exchange Kinetics ◽  
Kinetics Of

Abstract Water interactions and accessibility of the nanoscale components of plant cell walls influence their properties and processability in relation to many applications. We investigated the water-accessibility of nanoscale pores within the fibrillar structures of unmodified Norway spruce cell walls by small-angle neutron scattering (SANS) and Fourier-transform infra-red (FTIR) spectroscopy. The different sensitivity of SANS to hydrogenated ($$\hbox {H}_2\hbox {O}$$ H 2 O ) and deuterated water ($$\hbox {D}_2\hbox {O}$$ D 2 O ) was utilized to follow the exchange kinetics of water among cellulose microfibrils. FTIR spectroscopy was used to study the time-dependent re-exchange of OD groups to OH in wood samples transferred from liquid $$\hbox {D}_2\hbox {O}$$ D 2 O to $$\hbox {H}_2\hbox {O}$$ H 2 O . In addition, the effects of drying on the nanoscale structure and its water-accessibility were addressed by comparing SANS results and the kinetics of water exchange between never-dried and dried/rewetted wood samples. The results of the kinetic analyses allowed to identify two processes with different timescales. The diffusion-driven exchange of water in the spaces between microfibrils, which was observed with both SANS and FTIR, takes place within minutes and rather homogeneously. The second, slower process appeared only in the OD/OH re-exchange followed by FTIR, and it still continued after several weeks of immersion in $$\hbox {H}_2\hbox {O}$$ H 2 O . SANS could not detect any significant difference between the never-dried and dried/rewetted samples, whereas FTIR revealed a small portion of OD groups that resisted the re-exchange and this portion became larger with drying. Graphic abstract

THE ABSENCE OF ELASTIC DEFORMATION IN DRIED BENT CELLULOSE MICROFIBRILS IN PLANT CELL WALLS

1965 ◽  
Vol 43 (3) ◽  
pp. 339-343
Author(s):  
J. Ross Colvin
Keyword(s):  
Elastic Deformation ◽  
Plant Cell ◽  
Cell Walls ◽  
Cold Water ◽  
Hot Water ◽  
Cellulose Microfibrils ◽  
Plant Cell Walls ◽  
Avena Coleoptile ◽  
Parenchyma Cells ◽  
Embedding Medium

A small fraction of individual cellulose microfibrils in plant cell walls show appreciable bending along a portion of their length in a plane tangential to the cell surface. Segments of such curved microfibrils from transverse sections of Avena coleoptile epidermal or parenchyma cells do not straighten when they are freed from the constraints imposed by adjacent microfibrils, amorphous cell wall constituents, or the embedding medium. The curvature of these segments is not affected by immersion in cold water for 30 minutes, in hot water for 10 minutes, or in steam at 100° for 10 minutes. The results indicate that there is no elastic deformation of bent cellulose microfibrils in dried plant cell walls. The curvature of the microfibrils in the absence of elastic deformation suggests either (a) that cellulose microfibrils may be synthesized in a bent strain-free condition or (b) that cellulose microfibrils are synthesized in a straight form, followed by elastic deformation with subsequent release of strain by recrystallization on drying.

scholarly journals Cell wall composition determines handedness reversal in helicoidal cellulose architectures of Pollia condensata fruits

2021 ◽  
Vol 118 (51) ◽  
pp. e2111723118
Author(s):  
Yin Chang ◽  
Rox Middleton ◽  
Yu Ogawa ◽  
Tom Gregory ◽  
Lisa M. Steiner ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Hierarchical Structures ◽  
Cell Wall Composition ◽  
Cellulose Microfibrils ◽  
Plant Cell Walls ◽  
Mechanical Responses ◽  
Structural Colors ◽  
Left Handed ◽  
Helicoidal Structure

Chiral asymmetry is important in a wide variety of disciplines and occurs across length scales. While several natural chiral biomolecules exist only with single handedness, they can produce complex hierarchical structures with opposite chiralities. Understanding how the handedness is transferred from molecular to the macroscopic scales is far from trivial. An intriguing example is the transfer of the handedness of helicoidal organizations of cellulose microfibrils in plant cell walls. These cellulose helicoids produce structural colors if their dimension is comparable to the wavelength of visible light. All previously reported examples of a helicoidal structure in plants are left-handed except, remarkably, in the Pollia condensata fruit; both left- and right-handed helicoidal cell walls are found in neighboring cells of the same tissue. By simultaneously studying optical and mechanical responses of cells with different handednesses, we propose that the chirality of helicoids results from differences in cell wall composition. In detail, here we showed statistical substantiation of three different observations: 1) light reflected from right-handed cells is red shifted compared to light reflected from left-handed cells, 2) right-handed cells occur more rarely than left-handed ones, and 3) right-handed cells are located mainly in regions corresponding to interlocular divisions. Finally, 4) right-handed cells have an average lower elastic modulus compared to left-handed cells of the same color. Our findings, combined with mechanical simulation, suggest that the different chiralities of helicoids in the cell wall may result from different chemical composition, which strengthens previous hypotheses that hemicellulose might mediate the rotations of cellulose microfibrils.

scholarly journals From morphogenesis to pathogenesis: A cellulose loosening protein is one of the most widely distributed tools in nature

2019 ◽  
Author(s):  
William R. Chase ◽  
Olga Zhaxybayeva ◽  
Jorge Rocha ◽  
Daniel J. Cosgrove ◽  
Lori R. Shapiro
Keyword(s):  
Cell Wall ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Cell Walls ◽  
Growth And Development ◽  
Land Plants ◽  
Cellulose Microfibrils ◽  
Plant Cell Walls ◽  
Phylogenetic Distribution ◽  
Bacteria And Fungi

AbstractPlants must rearrange the network of complex carbohydrates in their cell walls during normal growth and development. To accomplish this, all plants depend on proteins called expansins that non-enzymatically loosen hydrogen bonds between cellulose microfibrils. Because of their key role in cell wall extension during growth, expansin genes are ubiquitous, diverse, and abundant throughout all land plants. Surprisingly, expansin genes have more recently been found in some bacteria and microbial eukaryotes, where their biological functions are largely unknown. Here, we reconstruct the phylogeny of microbial expansin genes. We find these genes in all eukaryotic microorganisms that have structural cellulose in their cell walls, suggesting expansins evolved in ancient marine microorganisms long before the evolution of land plants. We also find expansins in an unexpectedly high phylogenetic diversity of bacteria and fungi that do not have cellulosic cell walls. These bacteria and fungi with expansin genes inhabit varied ecological contexts mirroring the diversity of terrestrial and aquatic niches where plant and/or algal cellulosic cell walls are present. The microbial expansin phylogeny shows evidence of multiple horizontal gene transfer events within and between bacterial and eukaryotic microbial lineages, which may in part underlie their unusually broad phylogenetic distribution. Taken together, we find expansins to be unexpectedly widespread in both bacterial and eukaryotic genetic backgrounds, and that the contribution of these genes to bacterial and fungal ecological interactions with plants and algae has likely been underappreciated.ImportanceCellulose is the most abundant biopolymer on earth. In plant cell walls, where most global cellulose biomass is found, cellulose microfibrils occur intertwined with hemicelluloses and pectins. The rigidity of this polysaccharide matrix provides plant cell walls with structural support, but this rigidity also restricts cellular growth and development. Irreversible, non-enzymatic loosening of structural carbohydrates by expansin proteins is key to successful cell wall growth in plants and green algae. Here, we find that expansin genes are distributed far more broadly throughout diverse bacterial and fungal lineages lacking cellulosic cell walls than previously known. Multiple horizontal gene transfer events are in part responsible for their unusually wide phylogenetic distribution. Together, these results suggest that in addition to being the key evolutionary innovation by which eukaryotes remodel structural cellulose in their cell walls, expansins likely have remarkably broad and under-recognized utility for microbial species that interact with plant and algal structural cellulose in diverse ecological contexts.

Dehydration-induced physical strains of cellulose microfibrils in plant cell walls

2018 ◽  
Vol 197 ◽  
pp. 337-348 ◽  
Author(s):  
Shixin Huang ◽  
Mohamadamin Makarem ◽  
Sarah N. Kiemle ◽  
Yunzhen Zheng ◽  
Xin He ◽  
...  
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cellulose Microfibrils ◽  
Plant Cell Walls

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

Functional Fractionation of Platelets: Aggregation Kinetics and Glycoprotein Labeling of Differing Platelet Populations

1982 ◽  
Vol 48 (02) ◽  
pp. 211-216 ◽  
Author(s):  
V M Haver ◽  
A R L Gear
Keyword(s):  
Galactose Oxidase ◽  
Aggregation Kinetics ◽  
Maximal Rate ◽  
Membrane Glycoproteins ◽  
Whole Cells ◽  
Reversible Aggregation ◽  
Significant Difference ◽  
Small Doses ◽  
Major Loss ◽  
Kinetics Of

SummaryPlatelet heterogeneity has been studied with a technique called functional fractionation which employs gentle centrifugation to yield subpopulations (“reactive” and “less-reactive” platelets) after exposure to small doses of aggregating agent. Aggregation kinetics of the different platelet populations were investigated by quenched-flow aggregometry. The large, “reactive” platelets were more sensitive to ADP (Ka = 1.74 μM) than the smaller “less-reactive” platelets (Ka = 4.08 μM). However, their maximal rate of aggregation (Vmax, % of platelets aggregating per sec) of 23.3 was significantly lower than the “less-reactive” platelets (Vmax = 34.7). The “reactive” platelets had a 2.2 fold higher level of cyclic AMP.Platelet glycoproteins were labeled using the neuraminidase-galactose oxidase – [H3]-NaBH4 technique. When platelets were labeled after reversible aggregation, the “reactive” platelets showed a two-fold decrease in labeling efficiency (versus control platelets). However, examination of whole cells or membrane preparations from reversibly aggregated platelets revealed no significant difference in Coomassie or PAS (Schiff) staining.These results suggest that the large, “reactive” platelets are more sensitive to ADP but are not hyperaggregable in a kinetic sense. Reversible aggregation may cause a re-orientation of membrane glycoproteins that is apparently not characterized by a major loss of glycoprotein material.

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