Rheology of oil-in-water emulsions stabilised by native cellulose microfibrils in primary plant cells dispersions

2021 ◽  
pp. 100239
Author(s):  
Emma M. Nomena ◽  
Micah van der Vaart ◽  
Panayiotis Voudouris ◽  
Krassimir P. Velikov
2018 ◽  
Vol 1 (5) ◽  
pp. 1440-1447 ◽  
Author(s):  
Emma M. Nomena ◽  
Caroline Remijn ◽  
Faranaaz Rogier ◽  
Micah van der Vaart ◽  
Panayiotis Voudouris ◽  
...  

Nature ◽  
1964 ◽  
Vol 204 (4964) ◽  
pp. 1155-1157 ◽  
Author(s):  
R. ST. JOHN MANLEY

1956 ◽  
Vol 4 (3) ◽  
pp. 193 ◽  
Author(s):  
AB Wardrop

Autoradiographs have been prepared from parenchyma isolated from Avena coleoptile segments grown in a medium containing labelled glucose. The autoradiographs show that there is no concentration of radioactive material at the cell tips and labelled cellulose appears to be uniformly distributed in the cell wall. Electron micrographs of similar material show that the cellulose microfibrils are almost transversely oriented on the inner surface of the cell wall but are considerably dispersed from this direction on the outer surface. From this evidence it is concluded that growth in coleoptile parenchyma is not of the "bipolar" or "mosaic" types previously suggested, but corresponds to the "multi-net growth" of Roelofsen and Houwink. In addition a study has been made of the relation of microfibril orientation to cell form in parenchyma of onion root and in roots after treatment with colchicine, from which it is concluded that the final microfibril orientation on the outer wall surface is determined by the extent and polarity of its surface growth.


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.


1993 ◽  
Vol 20 (5) ◽  
pp. 461 ◽  
Author(s):  
H Shibaoka

Gibberellins control the direction of expansion of plant cells. They change the orientation of cellulose microfibrils by changing the orientation of cortical microtubules and, hence, the direction of cell expansion. When gibberellins change the orientation of cortical microtubules, they also change their stability. If the way in which gibberellins change the orientation of microtubules is identical to the way in which they change microtubule stability, then studies on the mechanism that regulates this stability should give us some clues to the mechanism that regulates the orientation of microtubules. With this possibility in mind, we undertook a series of studies on the stability of cortical microtubules. These revealed that the association of cortical microtubules with the plasma membrane is an important part of the mechanism for their stabilisation. Gibberellins seem to change the stability of microtubules by affecting their association with the plasma membrane. To study the way in which the gibberellins affect this association, it is necessary to clarify the molecular architecture of the structure that links cortical microtubules with the plasma membrane.


The membrane system is made up of the nuclear envelopes, rough and smooth endoplasmic reticulum, Golgi apparatus and plasmalemma. Interconnexions between the various parts of the system are shown and these probably represent a flow of membrane from the endoplasmic reticulum through the Golgi apparatus to the plasmalemma. Membrane fractions have been isolated from broken cells and their function in the synthesis of polysaccharides established. It has been shown that the matrix polysaccharides of the wall (pectic substances and hemicelluloses) are formed within the membranes and that the pattern of synthesis of these polymers changes during differentiation of the cells. Cellulose microfibrils are probably synthesized at the plasmalemma which is formed by incorporation of membrane bounded vesicles from the Golgi apparatus. Thus the assembly of the polymers takes place either when the membrane is within the cytoplasm or when it is incorporated as the plasmalemma of the cell.


1963 ◽  
Vol 19 (1) ◽  
pp. 239-250 ◽  
Author(s):  
M. C. Ledbetter ◽  
K. R. Porter

This paper reports an electron microscope examination of the cortices of some plant cells engaged in wall formation. Previous studies of similar material fixed in OSO4 alone have disclosed discontinuities in the plasma membrane and other evidence of inadequate fixation. After glutaraldehyde, used as a fixative in this present study, the general preservation of cortical fine structure is greatly improved. This is shown, for example, by the first evidence of slender tubules, 230 to 270 A in diameter and of indeterminate length, in plant cells of this type. They have been found in the cortical regions of cells of two angiosperms and one gymnosperm, representing all the material so far studied following this method of fixation. The tubules are identical in morphology to those also observed here in the mitotic spindles of plant cells, except that the latter have a somewhat smaller diameter. It is noted that the cortical tubules are in a favored position to govern cytoplasmic streaming and to exert an influence over the disposition of cell wall materials. In this regard it may be of some significance that the tubules just beneath the surface of the protoplast mirror the orientation of the cellulose microfibrils of the adjacent cell walls.


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