Nutritive efficiencies of lactalbumin and wheat gluten at very low levels of intake in adult rats

The nutritive values of proteins in relation to their intake levels were evaluated by feeding adult male rats weighing 250 g diets containing 0%, 0.39%, 0.78%, 1.56%, 2.34%, 3.90%, 7.79% and 15.58% lactalbumin or wheat gluten for three weeks. The biological values (BV) of both proteins were high at low levels of protein intake but decreased with increase in protein intake. The BV of wheat gluten was estimated to be about 100 at a level of intake of 1.56% but only 25 at a level of 15.58%. Similarly, the BV of lactalbumin decreased with increase in the protein level, being 67 at a level of 7.79%. The BVs of both proteins at low levels of dietary protein (below 2.34% of lactalbumin or 0.78% of wheat gluten) were apparently more than 100 because urinary N excretion was less than endogenous N. The BVs also decreased with time during the three-week test period. It is concluded that BV of a protein is not a fixed value but varies with the experimental conditions especially with changes in the amount of intake, and that differences in the qualities of various proteins cannot be compared quantitatively at a single level of protein. The results were briefly discussed in relation to protein requirements.

Immunochemical studies on bacterial blood group substances. VIII. The structure of oligosaccharides from blood group H-active polysaccharide of Escherichia coli 2B-V

Blood group H-active polysaccharide has been prepared from "smooth" strain Escherichia coli 2B-V by Freeman's method, alpha-Fucosidase derived from Bacillus fluminans caused the liberation of fucose from this polysaccharide, together with concomitant loss of blood group H activity. The results of quantitative microanalysis, borohydride reduction, the Morgan-Elson reaction and enzymic hydrolysis with betagalactosidase using isolated oligosaccharides obtained by partial acid hydrolysis indicated that the O-specific side chain of the polysaccharide has a pentassaccharide unit which is beta-D-Gal-(1 leads to 3)-D-GalNAc-(1 leads to 3)-D-GalNAc-Fuc with a D-glucose residue bound at some undetermined point on this structure. It was considered that terminal non-reducing fucose of the polysaccharide was liberated by partial acid hydrolysis.

Cytochemical study of exfoliated cells of oral mucosa. I. The glycogen deposition and keratinization

Cytochemical studies of glycogen of oral mucosa cells have been made on the smears by freeze-drying and PAS staining. The specimens were obtained from different areas of oral cavity of 77 human subjects and an attempt was made to find some interrelation amoung glycogen deposition, keratinization and inflammation. The largest glycogen deposition was found in the mucosa cells from mouth floor and cheek, a little in those from gingiva and quite a small or no glycogen in those from mucosa of hard palate and tongue. In gingiva the cells showing much more keratinization were less in glycogen contents, and vice versa. In inflammation some increase in glycogen contents were found in the gingivitis and the highest glycogen content in the cases of denture irritation of the palate as far as the present observation is concerned.

Fine structural and cytochemical observations on lamellar bodies in nerve cells of the medulla oblongata of the rat

Stuctures identified as lamellar bodies have observed in neurons of the dorsal sensory nucleus of the vagus of the rat medulla oblongata. They consist of stacks of parallel, regularly spaced cisternae which either run straight or curve forming a whorl. Finely textured, electron-dense fibrils are present between adjacent cisternae which are devoid of ribosomes. Ribosomes are attached only to the outermost surface of outer cisternae which are often continous with rough endoplasmic reticulum. Cytochemical studies reveal that these intercisternal fibrils contain abundant amino and imidazole groups as well as carboxyl groups. It is suggested that lamelar bodies arise by close alignment of parallel rough surfaced cisternae with subsqent loss of ribosomes from their surface. In addition, it is inferred that polar groups of intercisternal fibrils play an important role in the regular arrangement of cisternal membranes and in the dissociation of ribosomes from cisternae.