scholarly journals Tilted cellulose arrangement as a novel mechanism for hygroscopic coiling in the stork's bill awn

2011 ◽  
Vol 9 (69) ◽  
pp. 640-647 ◽  
Author(s):  
Yael Abraham ◽  
Carmen Tamburu ◽  
Eugenia Klein ◽  
John W. C. Dunlop ◽  
Peter Fratzl ◽  
...  
Keyword(s):  
Cell Wall ◽  
Simple Model ◽  
Single Layer ◽  
Cellulose Microfibrils ◽  
Wall Structure ◽  
Environmental Humidity ◽  
A Cell ◽  
Dispersal Unit ◽  
Bilayered Structure ◽  
Isotropic Foam

The sessile nature of plants demands the development of seed-dispersal mechanisms to establish new growing loci. Dispersal strategies of many species involve drying of the dispersal unit, which induces directed contraction and movement based on changing environmental humidity. The majority of researched hygroscopic dispersal mechanisms are based on a bilayered structure. Here, we investigate the motility of the stork's bill ( Erodium ) seeds that relies on the tightening and loosening of a helical awn to propel itself across the surface into a safe germination place. We show that this movement is based on a specialized single layer consisting of a mechanically uniform tissue. A cell wall structure with cellulose microfibrils arranged in an unusually tilted helix causes each cell to spiral. These cells generate a macroscopic coil by spiralling collectively. A simple model made from a thread embedded in an isotropic foam matrix shows that this cellulose arrangement is indeed sufficient to induce the spiralling of the cells.

The maturation of cell wall structure during germination of Bacillus polymyxa spores

1970 ◽  
Vol 16 (9) ◽  
pp. 883-887 ◽  
Author(s):  
R. G. E. Murray ◽  
Myrtle M. Hall ◽  
J. Marak
Keyword(s):  
Cell Wall ◽  
Intermediate Layer ◽  
Single Layer ◽  
Regular Structure ◽  
Wall Structure ◽  
Bacillus Polymyxa ◽  
Rectangular Array ◽  
Crack Open ◽  
Freeze Etching ◽  
Primordial Cell

Sections of germinating spores of Bacillus polymyxa show that the primordial cell wall consists of a single layer. The intermediate layer and an outer rectangular array of macromolecules found on vegetative cells do not appear until the spore coats crack open about 60 min after initiation of germination. The initial areas of the new components appear in patches under the cracks in the coats. Within 10 min the wall is completed and takes on the profile seen in the vegetative cell. Negative staining and freeze-etching techniques show the regular structure to be identical with that previously shown for mature cells, although the subunits are more readily visible in negatively stained preparations.

scholarly journals Affinity, life cycle, and intracellular complexity of organic-walled microfossils from the Mesoproterozoic of Shanxi, China

2015 ◽  
Vol 89 (1) ◽  
pp. 28-50 ◽  
Author(s):  
Heda Agić ◽  
Małgorzata Moczydłowska ◽  
Lei-Ming Yin
Keyword(s):  
Cell Wall ◽  
Life Cycle ◽  
Structural Complexity ◽  
Protective Role ◽  
Life Cycles ◽  
Wall Structure ◽  
Phenotypic Characters ◽  
Biological Affinity ◽  
New Material ◽  
A Cell

AbstractLight microscope and scanning electron microscope observations on new material of unicellular microfossilsDictyosphaera macroreticulataandShuiyousphaeridium macroreticulatum,from the Mesoproterozoic Ruyang Group in China, provide insights into the microorganisms’ biological affinity, life cycle and cellular complexity.Gigantosphaeridium fibratumn. gen. et sp., is described and is one of the largest Mesoproterozoic microfossils recorded. Phenotypic characters of vesicle ornamentation and excystment structures, properties of resistance and cell wall structure inDictyosphaeraandShuiyousphaeridiumare all diagnostic of microalgal cysts. The wide size ranges of the various morphotypes indicate growth phases compatible with the development of reproductive cysts. Conspecific biologically, each morphotype represents an asexual (resting cyst) or sexual (zygotic cyst) stage in the life cycle, respectively. We reconstruct this hypothetical life cycle and infer that the organism demonstrates a reproductive strategy of alternation of heteromorphic generations. Similarly inGigantosphaeridium,a metabolically expensive vesicle with processes suggests its protective role as a zygotic cyst. In combination with all these characters and from the resemblance to extant green algae, we propose the placement of these ancient microorganisms in the stem group of Chloroplastida (Viridiplantae). A cell wall composed of primary and secondary layers inDictyosphaeraandShuiyouisphaeridiumrequired a high cellular complexity for their synthesis and the presence of an endomembrane system and the Golgi apparatus. The plastid was also present, accepting the organism was photosynthetic. The biota reveals a high degree of morphological and cell structural complexity, and provides an insight into ongoing eukaryotic evolution and the development of complex life cycles with sexual reproduction by 1200 Ma.

scholarly journals Bundling of cellulose microfibrils in native and polyethylene glycol-containing wood cell walls revealed by small-angle neutron scattering

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Paavo A. Penttilä ◽  
Michael Altgen ◽  
Muhammad Awais ◽  
Monika Österberg ◽  
Lauri Rautkari ◽  
...  
Keyword(s):  
Cell Wall ◽  
Neutron Scattering ◽  
Plant Cell ◽  
Small Angle ◽  
Cell Walls ◽  
Small Angle Neutron Scattering ◽  
Plant Cell Wall ◽  
Raw Materials ◽  
Cellulose Microfibrils ◽  
Wall Structure

AbstractWood and other plant-based resources provide abundant, renewable raw materials for a variety of applications. Nevertheless, their utilization would greatly benefit from more efficient and accurate methods to characterize the detailed nanoscale architecture of plant cell walls. Non-invasive techniques such as neutron and X-ray scattering hold a promise for elucidating the hierarchical cell wall structure and any changes in its morphology, but their use is hindered by challenges in interpreting the experimental data. We used small-angle neutron scattering in combination with contrast variation by poly(ethylene glycol) (PEG) to identify the scattering contribution from cellulose microfibril bundles in native wood cell walls. Using this method, mean diameters for the microfibril bundles from 12 to 19 nm were determined, without the necessity of cutting, drying or freezing the cell wall. The packing distance of the individual microfibrils inside the bundles can be obtained from the same data. This finding opens up possibilities for further utilization of small-angle scattering in characterizing the plant cell wall nanostructure and its response to chemical, physical and biological modifications or even in situ treatments. Moreover, our results give new insights into the interaction between PEG and the wood nanostructure, which may be helpful for preservation of archaeological woods.

Orientation of macromolecules in the walls of elongating carrot cells

1993 ◽  
Vol 106 (4) ◽  
pp. 1347-1356
Author(s):  
M.C. McCann ◽  
N.J. Stacey ◽  
R. Wilson ◽  
K. Roberts
Keyword(s):  
Cell Wall ◽  
Single Cell ◽  
Cellulose Microfibrils ◽  
Replica Technique ◽  
Carrot Cells ◽  
Carrot Cell ◽  
A Cell ◽  
Complementary Techniques ◽  
Carrot Cell Suspension ◽  
Wall Components

When round cells from a carrot cell suspension culture are diluted into fresh medium without auxin, the cells elongate to almost 50 times their original diameter within three days. This process of elongation is accompanied by changes in both the composition and the orientation of cell wall polymers. We have obtained information on the orientation of wall polymers in elongating cells by two complementary techniques, one using microscopy and one spectroscopy. Images obtained by the fast-freeze, deep-etch, rotary-shadowed replica technique show that walls of round carrot cells have no net orientation of cellulose microfibrils, and that many thin fibres can be seen cross-linking microfibrils. Walls of elongated carrot cells, in contrast, show a marked net orientation of microfibrils at right angles to the axis of elongation. Fourier Transform Infrared (FTIR) spectra obtained from defined areas of single cell walls show that walls of round carrot cells contain more protein, esters and phenolics in a given area (10 microns × 10 microns) than walls of elongated carrot cells, that contain proportionally more carbohydrate. The orientation of particular functional groups, with respect to the direction of elongation of the cell, can be determined by inserting a polariser into the path of the infrared beam, before it passes through a cell wall sample mounted on the stage of the microscope accessory. In the walls of elongated cells, ester bands, amide bands characteristic of proteins, and stretching frequencies in the carbohydrate region of the spectrum all show a net orientation transverse to the long axis of the cells. In the walls of round carrot cells, however, there is no such net orientation of polymers. Spectra obtained from 25 microns-thick fresh sections of the etiolated stem of a carrot seedling show that different wall components are polarised in different tissue types. These techniques have therefore enabled us to define differences in both the composition and the architecture of walls of elongating cells at the level of a single cell, and to suggest that polymers not previously thought to be ordered, such as pectin and protein, are strictly oriented in some wall types.

Studies of the structure and chemical composition of the cell walls of Vaucheriaceae and Saprolegniaceae

1963 ◽  
Vol 158 (973) ◽  
pp. 435-445 ◽  
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Insoluble Fraction ◽  
Water Soluble ◽  
Hot Water ◽  
Cellulose Microfibrils ◽  
Wall Material ◽  
Native Cellulose ◽  
A Cell ◽  
Crystalline Component

The cell walls of members of the Vaucheriaceae and Saprolegniaceae have been examined by X-ray analysis and electron microscopy, and their composition determined by hydrolysis and paper partition chromatography of the hydrolysates. Both differences and similarities between the members of these two species examined are found to supplement the comparative morphological and physiological information at present available. Saprolegnia , Achlya , Brevilegnia and Dictyuchus among the Saprolegniaceae possess hot-water soluble polysaccharides containing glucose residues only. This polysaccharide is not crystallographically identical with the polysaccharide found in Vaucheria sessilis with a similar solubility. The members of the Saprolegniaceae contain large amounts of alkali-soluble polysaccharides in contrast with the negligible amount found in V. sessilis . These polysaccharides are only weakly crystalline, but the indications are that the same polysaccharides may occur through­out the Saprolegniaceae. The alkali-insoluble wall material of Vaucheria species consists of highly crystalline native cellulose with large, apparently randomly arranged, microfibrils. The hydrolysate of this material contains ribose, xylose and arabinose in addition to glucose, presumably representing strongly bound pentosans. Native cellulose also occurs in the Saprolegniaceae but only in small proportion. The bulk of the alkali-insoluble fraction in the walls of these fungi appears amorphous in the electron microscope and is only weakly crystalline. It consists of one or m ore substances containing glucose, mannose, ribose and possibly other sugars together with traces of glucosamine. These substances presumably cover the cellulose microfibrils. The total quantity of non-cellulosic polysaccharide in the Saprolegniaceae approaches 85% of the total wall weight in contrast with the situation in Vaucheria where the cellulose alone approaches 90% of the total cell wall. Dichotomosiphon is unique among the organism s studied in this paper, in possessing a cell wall entirely soluble in alkali and composed of approximately equal quantities of glucose and xylose. The crystalline component is aβ-1,3-linked xylan, as already reported for some of the Siphonales (closely related algae) by Frei & Preston.

scholarly journals The Root Cap Cuticle: A Cell Wall Structure for Seedling Establishment and Lateral Root Formation

Cell ◽  
2019 ◽  
Vol 176 (6) ◽  
pp. 1367-1378.e8 ◽  
Author(s):  
Alice Berhin ◽  
Damien de Bellis ◽  
Rochus B. Franke ◽  
Rafael A. Buono ◽  
Moritz K. Nowack ◽  
...  
Keyword(s):  
Cell Wall ◽  
Seedling Establishment ◽  
Lateral Root ◽  
Root Formation ◽  
Root Cap ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Lateral Root Formation ◽  
A Cell

scholarly journals Caldicoprobacter oshimai gen. nov., sp. nov., an anaerobic, xylanolytic, extremely thermophilic bacterium isolated from sheep faeces, and proposal of Caldicoprobacteraceae fam. nov.

2010 ◽  
Vol 60 (1) ◽  
pp. 67-71 ◽  
Author(s):  
Hiroshi Yokoyama ◽  
Isaac D. Wagner ◽  
Juergen Wiegel
Keyword(s):  
Cell Wall ◽  
Potato Starch ◽  
Single Layer ◽  
Thermophilic Bacterium ◽  
Wall Structure ◽  
Rrna Gene ◽  
Fermentation Products ◽  
University Of Georgia ◽  
Casamino Acids ◽  
The University

An obligately anaerobic, xylanolytic, extremely thermophilic bacterium, strain JW/HY-331T, was isolated from sheep faeces collected from a farm at the University of Georgia, USA. Cells of strain JW/HY-331T stained Gram-positive and were catalase-negative, non-motile rods. Single terminal endospores (0.4–0.6 μm in diameter) swelled the mother cell. Growth ranges were 44–77 °C (optimum 70 °C at pH70 °C 7.2) and pH70 °C 5.9–8.6 (optimum 7.2 at 70 °C). Salt tolerance was 0–2.0 % (w/v) NaCl. No growth was observed at or below 42 °C or at or above 79 °C or at pH70 °C 5.7 and below or 8.9 and above. In the presence of 0.3 % yeast extract and 0.1 % tryptone, strain JW/HY-331T utilized xylose, glucose, galactose, cellobiose, raffinose and xylan as carbon and energy sources, but not dextran, soluble potato starch, CM-cellulose, cellulose powder, casein or Casamino acids. Fermentation products from glucose were lactate, acetate, ethanol, CO2 and H2. The G+C content of the genomic DNA was 45.4 mol% (HPLC). Major cellular fatty acids were iso-C17 : 0, iso-C15 : 0 and anteiso-C17 : 0. No respiratory quinones were detected. The cell-wall structure was a single layer (Gram-type positive) of the peptidoglycan type A1γ; the cell-wall sugars were galactose and mannose. Based on 16S rRNA gene sequence analysis, ‘Catabacter hongkongensis’ HKU16 (85.4 % similarity), Caloramator fervidus ATCC 43204T (84.2 %) and Caloranaerobacter azorensis MV1087T (83.4 %) were the closest relatives, but they were only distantly related to strain JW/HY-331T. On the basis of physiological, chemotaxonomic and phylogenetic data, isolate JW/HY-331T (=DSM 21659T =ATCC BAA-1711T) is proposed as the type strain of Caldicoprobacter oshimai gen. nov., sp. nov., placed in Caldicoprobacteraceae fam. nov. within the order Clostridiales of the phylum Firmicutes.

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