Microscopic structure and distribution of various elements in the eggshell of the Black-tailed Gull, Larus crassirostris, as revealed by scanning and transmission electron microscopy and X-ray compositional microanalysis

Abstract

The present paper describes the microscopic structure and distribution of various elements in the eggshell from the Black-tailed Gull Larus crassirostris. Scanning and transmission electron microscopy (SEM and TEM) in combination with light microscopy demonstrated four major zones in the eggshell: the shell membrane (SM), the mammillary zone (MZ), the palisade region (PR), and the cuticle layer (CL). The SM was composed of a further three layers: i.e. the limiting membrane and the inner and outer SMs consisting of thin fibers. The MZ was a layer lined with conical knobs, the mammillare, each of which had a core portion characterized by a dense matrix with a few vesicles and aggregated fine fibrils. The PR showed a spongy feature depicted as numerous vesicles embedded in a calcified matrix. The CL appeared as a simple structure different from that seen in the eggshells from other birds, such as grebes, cormorants and domestic fowl. X-ray compositional microanalysis (XCM) revealed differences in the distribution patterns of certain elements (Ca, Mg, and P) in the radial face of the eggshell. The concentration of Ca was markedly high throughout the true shell (MZ and PR), whereas that of Mg was locally high in the MZ. The concentration of P was slightly higher in the surface crystal layer of the PR than elsewhere.

High activity of acid-treated quail eggshell catalysts in the transesterification of palm oil with methanol

“…The 2-h acid treatment of quail eggshell decreased the phosphorous content from 1.1% to 0.1%. Due to the relatively high phosphorous content of the cuticle layer, the acid treatment-induced decrease in the phosphorous content demonstrated the removal of the cuticle layer (Chiba, 2004). Several other inorganic materials were detected at very low levels.…”

Low-temperature ZnO atomic layer deposition on biotemplates: flexible photocatalytic ZnO structures from eggshell membranes

“…Even though the ESM is stable against the reaction byproducts of the ALD process (e.g. isopropanol), 24,25 as stated above, upon heating (around 240 1C) it undergoes pyrolysis. 44 For coating of the ISM with ZnO, the pyrolysis is not a critical issue, the highest photocatalytic efficiency and preservation of the original structures of ISM can be assured by virtue of low processing temperatures (o240 1C).…”

“…However, this is not the case. It is known that the collagen based ESM contains functional groups, such as amines, amides and carboxylates 24,25 which may interact with the ALD precursors (TIP or DEZ/water) during the deposition. During the alternating exposure/purge sequence of the ALD precursor pairs, the highly reactive precursors chemically interact with the ISM fiber surface as well as the bulk of the protein structures (results will be published elsewhere).…”

“…It prevents bacterial invasions, thus protecting the embryo. [23][24][25] We deposited TiO 2 or ZnO by ALD on this ISM, both of which show bactericidal photocatalytic effects under UV illumination (ISM/TiO 2 and ISM/ZnO). 26,27 We investigated the bactericidal properties of those membranes and characterized them quantitatively using a photocatalytic reaction which inactivated Escherichia coli (E. coli) bacteria.…”