Algae Nitella

Mimosa pudica and insectivore type, Drosera rotundifolia, Dionaea muscipula, and the cells of algae Nitella and Char a [62,63],... 

An impressive demonstration that myosin heads do move along the actin filaments was provided by Sheetz and Spudich, who found that myosin-coated fluorescent beads 0.7 pm in diameter will move along actin filaments from cells of the alga Nitella in an ATP-dependent fashion at velocities similar to those required in muscle.149 The myosin heads literally glide along the thick cables of parallel actin filaments present in these algae. 

R Ligrone, A Carafa, JG Duckett, KS Renzagha, K Ruel. Immunocytochemical detection of hgnin-related epitopes in cell walls in hryophytes and the charalean alga Nitella. PI Syst Evol 270 257-272, 2008. 

The freshwater macrophytic alga Nitella spp. (stonewort) is capable of removing TNT from water [35], The specific first-order rate constant for TNT uptake by this organism is 2.94 x 10 3 L g FW h which is comparable to vascular freshwater... 

The spear-type glass microelectrode (Hinke-type) (2) (Figure la) has been used to determine the intracellular pH of the crab muscle fibers (3,4), cytoplasm of the giant squid axon (5), rat sartorius muscle fibers (6), rat atrial muscle fibers (7), vacuole of the algae Nitella flexilis (8), rat kidney tubular fluid (9,10), nerve cells of mollusk ganglia (11), and skeletal muscle fibers of the rat (4,12,13,14). 

Fig. 2.6. Relationship between (protoplast water potential), IPj (water potential due to protoplast solutes = osmotic potential of cell sap), We (water potential of the bathing solution with which cell is in equilibrium) and W, (turgor potential). (The data refers to cells of the alga Nitella and is derived from H. Tamuya, Cytologia Tokyo), 8 542, 1938.) Note that and Wp become less negative as the cells become more turgid while W, becomes more positive —W, more negative).

Such a study has been performed on a model plant system, the Nitella flexilis cell wall [1, 2, 3]. This freshwater alga has giant intemodal cells whose easily isolated cell walls constitute a simplified model of higher plant cell walls it has no lignin and its pectin is not methylesterified. Isolated cell walls are cut in pieces and distributed in different lots over the whole exchange isotherm to reduce variability between experimental points. 

The movement of glycosides and most of their hydrolytic products across the plasmalemma into the cell generally occurs by means of carriers associated with the plasmalemma. Without such carriers,- the plasmalemma is effectively impermeable to sugars25 but some molecules, such as methanol,250 may enter cells by simple diffusion, as described for the stoneworts (algae) Chara australis and Nitella translu-cens.26... 

The electrical potential difference across the membrane can be measured by placing appropriate electrodes on its two sides. To measure the potential across a cell membrane one electrode must be within the protoplast and preferably we should be able to ascertain whether it is in the vacuole or in the cytoplasm (since in one case it will be separated from the electrode in the external solution by tono-plast and plasmalemma and in the other only by the plasmalemma). To undertake such measurements very fine microelectrodes are needed electrodes have been used, the glass tips of which have a diameter of ca. 1 micron (/tm). Even with such electrodes large vacuolated cells rich in cytoplasm are needed, such large cells are also required to obtain adequate samples of vacuolar sap and of cytoplasm for accurate analysis of all their major ions, and for measurements of their ion fluxes. To meet these requirements experimenters have turned to the giant multinucleate cells of certain algae, notably species of Nitella, Hydrodictyon and Chora. 

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