Hen eggs

Rubidium is also incorporated into hen s eggs. Hens were found to excrete only 25% of their intake via the feces and urine (Sarudi et al. 1995). 

Age maturity Eggs/hen % Peak prod. Final Body Average Egg... 

The principal interest in photosynthetic bacteria for thek appHcabiUty to SCP production (Table 1) has been in Japan, where Jiodobacter capsulatus has been used to treat industrial wastes in sewage ponds (40,41). The product has been evaluated as a protein supplement in laying hen rations for egg production with acceptable results (40). 

The egg shell is 94% calcium carbonate [471-34-17, CaCO, 1% calcium phosphate [7758-23-8] and a small amount of magnesium carbonate [546-93-0]. A water-insoluble keratin-type protein is found within the shell and in the outer cuticle coating. The pores of the shell allow carbon dioxide and water to escape during storage. The shell is separated from the egg contents by two protein membranes. The air cell formed by separation of these membranes increases in size because of water loss. The air cell originally forms because of the contraction of the Hquid within the egg shell when the temperature changes from the body temperature of the hen at 41.6°C to a storage temperature of the egg at 7.2°C. 

R. B. Chapin, S ome Factors Affecting the EmulsiJyingProperties of Hen s Egg, Ph.D. dissertation, Iowa State College, Ames, Iowa, 1951. 

From hen egg white. Purified by solvent extraction and chromatography on alumina. Suspended in distilled water and kept frozen until used [Lee and Hunt J Am Chem Soc 106 7411 1984, Singleton et al. J Am Oil Chem Soc 42 53 7965]. For purification of commercial egg lecithin see Pangborn [J Biol Chem 188 471 7957]. 

Figure 3 Calculated X-ray diffuse scattering patterns from (a) a full molecular dynamics trajectory of orthorhombic hen egg white lysozyme and (b) a trajectory obtained by fitting to the full trajectory rigid-body side chains and segments of the backbone. A full description is given in Ref. 13.

WJ Browne, ACT North, DC Phillips, K Brew, TC Vanaman, RC Hill. A possible three-dimensional stnicture of bovine a-lactalbumin based on that of hen s egg-white lysozyme. J Mol Biol 42 65-86, 1969. 

Both attractive forces and repulsive forces are included in van der Waals interactions. The attractive forces are due primarily to instantaneous dipole-induced dipole interactions that arise because of fluctuations in the electron charge distributions of adjacent nonbonded atoms. Individual van der Waals interactions are weak ones (with stabilization energies of 4.0 to 1.2 kj/mol), but many such interactions occur in a typical protein, and, by sheer force of numbers, they can represent a significant contribution to the stability of a protein. Peter Privalov and George Makhatadze have shown that, for pancreatic ribonuclease A, hen egg white lysozyme, horse heart cytochrome c, and sperm whale myoglobin, van der Waals interactions between tightly packed groups in the interior of the protein are a major contribution to protein stability. 

Lysozyme is an enzyme that hydrolyzes polysaccharide chains. It ruptures certain bacterial cells by cleaving the polysaccharide chains that make up their cell wall. Lysozyme is found in many body fluids, but the most thoroughly studied form is from hen egg whites. The Russian scientist P. Laschtchenko first described the bacteriolytic properties of hen egg white lysozyme in 1909. In 1922, Alexander Fleming, the London bacteriologist who later discovered penicillin, gave the name lysozyme to the agent in mucus and tears that destroyed certain bacteria, because it was an enzyme that caused bacterial lysis. 

Hen egg-white lysozyme catalyzes the hydrolysis of various oligosaccharides, especially those of bacterial cell walls. The elucidation of the X-ray structure of this enzyme by David Phillips and co-workers (Ref. 1) provided the first glimpse of the structure of an enzyme-active site. The determination of the structure of this enzyme with trisaccharide competitive inhibitors and biochemical studies led to a detailed model for lysozyme and its hexa N-acetyl glucoseamine (hexa-NAG) substrate (Fig. 6.1). These studies identified the C-O bond between the D and E residues of the substrate as the bond which is being specifically cleaved by the enzyme and located the residues Glu 37 and Asp 52 as the major catalytic residues. The initial structural studies led to various proposals of how catalysis might take place. Here we consider these proposals and show how to examine their validity by computer modeling approaches. 

LD model, see Langevin dipoles model (LD) Linear free-energy relationships, see Free energy relationships, linear Linear response approximation, 92,215 London, see Heitler-London model Lysine, structure of, 110 Lysozyme, (hen egg white), 153-169,154. See also Oligosaccharide hydrolysis active site of, 157-159, 167-169, 181 calibration of EVB surfaces, 162,162-166, 166... 

Blake CC, Koeniz DF, Mair GA, North AC, Phillips DC, Sarma VR. Structure of hen egg-white lysozyme. A three-dimensional Fourier synthesis at 2 Angstrom resolution. Nature 1965 206 757-61. 

From crystal-structure analysis of hen-egg lysozyme and of its complex with the competitive inhibitor tri-Af-acetylchitotriose, the following conclusions were drawn the active site consists of a cleft containing six sub-sites, A to F, of which each could accommodate a) -( 1 — 4)-linked A-acetylglucosa-... 

Tests have been published for determining toxicity towards leucocytes. Evaluation on the infected chorioallantoic membrane of hens eggs was suggested as being a useful method of testing potential wound disinfectants. 

Viruses replicate only in living cells so the first viral vaccines were necessarily made in animals smallpox vaccine in the dermis of calves and sheep and rabies vaccines in the spinal cords of rabbits and the brains of mice. Such methods are no longer used in advanced vaccine production and the only intact animal hosts that are used are embryonated hens eggs. Almost all of the vims that is needed for viral vaccine production is obtained from cell cultures infected with vims of the appropriate strain. 

Embryonated hens eggs are still the most convenient hosts for the growth of the vimses that are needed for influenza and yellow fever vaccines. Influenza vimses accumulate in high litre in the allantoic fluid of the eggs and yellow fever vims accumulates in the nervous systems of the embryos. 

Influenza (split virion)t Allantoic fluid from embryonated hens eggs infected with influenza viruses A and B 1 Harvest of viruses 2 Disruption with surface active agent 3 Blending of components of different serotypes Assay of haemagglutinin content by immunodiffusion Inoculation of embryonated hens eggs to exclude live virus... 

HDL Hi -dcnsity lipoprotein HEL Hen egg white lysozyme HEPE Hydroxyeicosapentanoic acid HEPES N-2-... 

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