The involvement of Microbial Epiphytes in Uptake Measurements with the Giant-celled Alga Chara australis

1988 ◽  
Vol 15 (4) ◽  
pp. 483
Author(s):  
MR Wilson ◽  
JM Hush ◽  
NA Walker
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Algal Cell ◽  
Pond Water ◽  
Substantial Contribution ◽  
Free Paper ◽  
Solute Uptake ◽  
Water Ph ◽  
Chara Australis ◽  
Transport Of Ions

The giant-celled algae Chara and Nitella have been used extensively in studies of the transport of ions and other solutes. Before this report, uptake measurements were made without a detailed consideration of the effects of microbial epiphytes living on the external surface of the algal cell wall. Examination of the cell walls of Chara and Nitella with the scanning electron microscope revealed the presence of an often dense microflora consisting of diatoms, many types of bacteria, and even fungi. The contribution of this microflora to uptake measurements made with radiotracers was estimated by using isolated Chara cell wall cylinders internally filled with a silicone compound. For the Chara tested by us, the microflora was shown to make a substantial contribution to the uptake of urea, uric acid and glycine measured for untreated internodes. It was shown that, by briefly soaking Chara internodes in an artificial pond water, pH 8.5, containing 3 mM EGTA and then wiping their surfaces with a Kimwipe (a lint-free paper tissue), the microbial epiphytes can be quickly and simply removed. This treatment could be very useful in radiotracer studies of giant-celled algae in which the activity of the surface microflora complicates measurements of solute uptake.

scholarly journals Ionic Relations of Cells of Chara Australis II. The Indiffusible Anions of the Cell Wall

1960 ◽  
Vol 13 (3) ◽  
pp. 267 ◽  
Author(s):  
J Dainty ◽  
AB Hope ◽  
Christine Denby
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
External Concentration ◽  
Chara Australis ◽  
The Mean ◽  
Ionic Relations ◽  
Isolated Cell

Studies of isolated cell walls from Ohara australi8 have been extended to measure the concentration of the endogenous anions of the wall and the pK of the acids which ionize to give these anions. The conce'ntration of in diffusible anions in the wall is O� 8 equiv/l when the external concentration of cations is 20 mN but may be higher when it is greater than this. The mean pK of the acids from which the wall anions are derived is 2� 2.

scholarly journals Comparative transcriptomics reveals the molecular toolkit used by an algivorous protist for cell wall perforation

2021 ◽  
Author(s):  
Jennifer V. Gerbracht ◽  
Tommy Harding ◽  
Alastair G. B. Simpson ◽  
Andrew J. Roger ◽  
Sebastian Hess
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cell Biology ◽  
Algal Cell ◽  
Feeding Strategies ◽  
Generalist Predators ◽  
Related Factors ◽  
Prey Cell ◽  
Complex Behaviour ◽  
Green Algal

Microbial eukaryotes display a stunning diversity of feeding strategies, ranging from generalist predators to highly specialised parasites. The unicellular protoplast feeders represent a fascinating mechanistic intermediate, as they penetrate other eukaryotic cells (algae, fungi) like some parasites, but then devour their cell contents by phagocytosis. Besides prey recognition and attachment, this complex behaviour involves the local, pre-phagocytotic dissolution of the prey cell wall, which results in well-defined perforations of species-specific size and structure. Yet, the molecular processes that enable protoplast feeders to overcome cell walls of diverse biochemical composition remain unknown. We used the flagellate Orciraptor agilis (Viridiraptoridae, Rhizaria) as a model protoplast feeder, and applied differential gene expression analysis to examine its penetration of green algal cell walls. Besides distinct expression changes that reflect major cellular processes (e.g. locomotion, cell division), we found lytic carbohydrate-active enzymes that are highly expressed and upregulated during the attack on the alga. A putative endocellulase (family GH5_5) with a secretion signal is most prominent, and a potential key factor for cell wall dissolution. Other candidate enzymes (e.g. lytic polysaccharide monooxygenases) belong to families that are largely uncharacterised, emphasising the potential of non-fungal micro-eukaryotes for enzyme exploration. Unexpectedly, we discovered various chitin-related factors that point to an unknown chitin metabolism in Orciraptor, potentially also involved in the feeding process. Our findings provide first molecular insights into an important microbial feeding behaviour, and new directions for cell biology research on non-model eukaryotes.

A review about brown algal cell walls and fucose-containing sulfated polysaccharides: Cell wall context, biomedical properties and key research challenges

2017 ◽  
Vol 175 ◽  
pp. 395-408 ◽  
Author(s):  
Estelle Deniaud-Bouët ◽  
Kevin Hardouin ◽  
Philippe Potin ◽  
Bernard Kloareg ◽  
Cécile Hervé
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Algal Cell ◽  
Sulfated Polysaccharides ◽  
Research Challenges

scholarly journals Insights into cell wall disintegration of Chlorella vulgaris

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262500
Author(s):  
Sophie Weber ◽  
Philipp M. Grande ◽  
Lars M. Blank ◽  
Holger Klose
Keyword(s):  
Cell Wall ◽  
Chlorella Vulgaris ◽  
Cell Walls ◽  
Algal Cell ◽  
Monosaccharide Composition ◽  
Total Biomass ◽  
Algal Cell Wall ◽  
Wall Structures ◽  
Valuable Compounds ◽  
Hydrolysis Of

With their ability of CO2 fixation using sunlight as an energy source, algae and especially microalgae are moving into the focus for the production of proteins and other valuable compounds. However, the valorization of algal biomass depends on the effective disruption of the recalcitrant microalgal cell wall. Especially cell walls of Chlorella species proved to be very robust. The wall structures that are responsible for this robustness have been studied less so far. Here, we evaluate different common methods to break up the algal cell wall effectively and measure the success by protein and carbohydrate release. Subsequently, we investigate algal cell wall features playing a role in the wall’s recalcitrance towards disruption. Using different mechanical and chemical technologies, alkali catalyzed hydrolysis of the Chlorella vulgaris cells proved to be especially effective in solubilizing up to 56 wt% protein and 14 wt% carbohydrates of the total biomass. The stepwise degradation of C. vulgaris cell walls using a series of chemicals with increasingly strong conditions revealed that each fraction released different ratios of proteins and carbohydrates. A detailed analysis of the monosaccharide composition of the cell wall extracted in each step identified possible factors for the robustness of the cell wall. In particular, the presence of chitin or chitin-like polymers was indicated by glucosamine found in strong alkali extracts. The presence of highly ordered starch or cellulose was indicated by glucose detected in strong acidic extracts. Our results might help to tailor more specific efforts to disrupt Chlorella cell walls and help to valorize microalgae biomass.

A reappraisal of thermodynamic transport coefficients in Nitella cell walls

1969 ◽  
Vol 47 (9) ◽  
pp. 1497-1503 ◽  
Author(s):  
M. T. Tyree ◽  
D. C. Spanner
Keyword(s):  
Cell Wall ◽  
Detailed Analysis ◽  
Salt Concentration ◽  
Cell Walls ◽  
Transport Coefficients ◽  
Xylem Sap ◽  
Pond Water ◽  
Thermodynamic Efficiency ◽  
Peak Efficiency ◽  
Membrane Complex

A reanalysis of the published thermodynamic transport coefficients has led to the conclusion that the contribution of Nitella cell walls to the electroosmotic efficiency of the wall – membrane complex in living Nitella cells has been incorrectly estimated. When the e-o efficiency observed in the living Nitella cell is less than 100 moles Faraday−1 the observed value is an overestimate if attributed to the membrane alone; when the e-o efficiency observed is over 100 moles Faraday−1 the value is an underestimate of the e-o in the membrane. A more detailed analysis of the salt concentration dependence of LPE (the electrokinetic coefficient) and of LPE2/LEELPP (the relative thermodynamic efficiency of electroosmosis) is given. It is found that LPE2/LEELPP reaches a peak efficiency (about 0.6) at about the saline concentration of pond water and xylem sap. It is concluded that the suggestion of Briggs that the electroosmosis observed in living Nitella cells may be a property of the cell wall alone is unlikely to be true.

Silicification of wood-cell walls

1994 ◽  
Vol 52 ◽  
pp. 428-429
Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Resin Composite ◽  
Middle Lamella ◽  
Cellulose Fibers ◽  
Complex Structures ◽  
Rich Region ◽  
Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

Histological aspects of the cryopreservation of potato

2008 ◽  
Vol 56 (3) ◽  
pp. 341-348
Author(s):  
P. Pepó ◽  
A. Kovács
Keyword(s):  
Cell Wall ◽  
Low Temperatures ◽  
Cell Walls ◽  
Cellular Level ◽  
Adaptive Mechanism ◽  
Epidermal Layer ◽  
Freezing And Thawing ◽  
Meristematic Cells ◽  
Suitable Solution ◽  
Vacuolated Cells

Cryopreservation appears to be a suitable solution for the maintenance of potato germplasms. The protocol described in this paper can be applied for the vitrification and preservation of meristems. During histo-cytological studies it is possible to observe modifications at the cellular level and to understand the adaptive mechanism to low temperatures. Control potato meristem tissue contained a number of meristematic cells with a gradient of differentiation. After freezing there were a large number of vacuolated cells, some of which exhibited broken cell walls and plasmolysis. The thickening of the cell wall, giving them a sinuous appearance, was observed after freezing and thawing the meristems, with ruptures of the cuticle and epidermal layer.

scholarly journals Plant Cell Wall Hydration and Plant Physiology: An Exploration of the Consequences of Direct Effects of Water Deficit on the Plant Cell Wall

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1263
Author(s):  
David Stuart Thompson ◽  
Azharul Islam
Keyword(s):  
Cell Wall ◽  
Water Content ◽  
Bacterial Cellulose ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Plant Cell Walls ◽  
Cell Wall Polysaccharides ◽  
Degree Of Hydration ◽  
Cellulose Composites

The extensibility of synthetic polymers is routinely modulated by the addition of lower molecular weight spacing molecules known as plasticizers, and there is some evidence that water may have similar effects on plant cell walls. Furthermore, it appears that changes in wall hydration could affect wall behavior to a degree that seems likely to have physiological consequences at water potentials that many plants would experience under field conditions. Osmotica large enough to be excluded from plant cell walls and bacterial cellulose composites with other cell wall polysaccharides were used to alter their water content and to demonstrate that the relationship between water potential and degree of hydration of these materials is affected by their composition. Additionally, it was found that expansins facilitate rehydration of bacterial cellulose and cellulose composites and cause swelling of plant cell wall fragments in suspension and that these responses are also affected by polysaccharide composition. Given these observations, it seems probable that plant environmental responses include measures to regulate cell wall water content or mitigate the consequences of changes in wall hydration and that it may be possible to exploit such mechanisms to improve crop resilience.

Sign in / Sign up

Export Citation Format

Share Document