Valonia ventricosa

Figure 21. Immunofluorescence micrograph of perinuclear microtubules in the aplanospore of 3h post-wounding of Valonia ventricosa.

Lamellar, single crystals of ivory-nut mannan were studied by electron diffraction. The base-plane dimensions of the unit cell are a = 0.722 nm and b = 0.892 nm. The systematic absences confirmed the space group P212121. The diffraction pattern did not change with the crystallization temperature. Oriented crystallization ofD-mannan with its chain axis parallel to the microfibril substrates, Valonia ventricosa and bacterial cellulose, was discovered ( hetero-shish-kebabs ). 

In one outline, cellulose from Valonia ventricosa, an alga, was boiled in excess 1% aqueous NaOH for 6 h, with a change of alkali solution after 3 h the alkali-treated cellulose was washed with distilled water (Blackwell, et al., 1977), then immersed overnight in 0.05-N HC1 at room temperature. The... 

However, Marchessault and Sundararajan (1983) found no evidence of periodic disordered regions using dark field electron microscopy with Valonia ventricosa so they can be no larger than the limit of resolution (< 0.5 nm). Further, this hypothesis has contradictions. There is no logical reason why defects should be swept some distance along the microfibril rather than escaping laterally to the surface. 

Cellulose microcrystals extracted from valonia ventricosa are prepared according to [97] to yield cellulose suspensions. For AFM, a 5-pl drop of a 100-fold diluted (water) suspension is deposited onto freshly cleaved mica and left to dry under ambient conditions. For imaging under propanol, the samples are deposited onto 3-aminopropyltriethoxysilane-functionalized mica [98]. 

The properties of vicinal water are known frequently to change rather abruptly as a function of temperature. Figures 8 and 9 show the survival of the green macroalga Valonia ventricosa and the caridean shrimp Periclimenes as a function... 

Figure 8. Percentage survival of the alga Valonia ventricosa after 3 days of exposure to various temperatures. Note changes near 15-16 and 31-32 C. (From Thorhaug, 1976 see also Drost-Hansen, 1981).

Although one can have a broad picture of how Type A function comes about, the detailed kinetics and thermodynamics still present unsolved problems. The planar, hydrophobic, aromatic face presented by all the protein folds that have Type A function suggests that the driving force is hydrophobic and that therefore Type A CBDs should bind preferentially to hydrophobic faces of the polysaccharide crystal. Indeed, with gold-labelled CBM 1 and CBM 3 binding to cellulose lo, (triclinic) crystals of Valonia ventricosa, electron microscopy reveals just that - preferential binding to the (110) face of the crystal. 

The binding does not appear irreversible in two dimensions, however two-dimensional diffusion on the surface of a Valonia ventricosa crystal to two CBM 2as from C.fimi was demonstrated." Obviously, having a CBM which bound a catalytic domain not only irreversibly but also immovably would vitiate its biological function. 

Figure 5 CP/MAS spectra of several cellulose I samples (a) ramie, (b) cotton linters, (c) hydrocellulose from cotton llnters, (d) low-DP regenerated cellulose I, (e) Acetobacterxylinum cellulose, and (f) Valonia ventricosa cellulose. After D. L. VanderHart R. H. Atalla, Macromolecular 984, 17, 1465 and R. H. Atalla D. L. VanderHart, Science 1984, 223, 283.

Fig. 42. Dif action-contrast transmission electron microscopy of a fragment of Valonia ventricosa cell-wall cross-sectioned perpendicular to one of the main microfibrillar directions. The pictme is printed in reverse contrast, so that the cross-sectioned microfibrils appear as white squares. (See Color Plate 17.)...

R. D. Preston, E. Nicolai, R. Reed, and A. Mallard, Electron-microscopic study of cellulose in the wall of Valonia ventricosa, Nature, 162 (1948) 665-667. 

J. F. Revol and D. A. I. Goring, Directionality of the fiber c-axis of cellulose crystallites in microfibrils of Valonia ventricosa. Polymer, 24 (1983) 1547-1550. 

Revol, J.F. On the cross-sectional shape of cellulose crystallites in Valonia ventricosa. Carbohydr. Polym. 2, 123-134 (1982)... 

In particularly pure form and high crystallinity, cellulose is synthesized by certain bacteria (e.g. Acetobacter xylinus) and occurs in certain algae (e.g. Valonia ventricosa). These sources are important for basic research and are not used to produce thermoplastic cellulose material. 

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