o-Quinones formed in plant extracts. Their reactions with amino acids and peptides

1. The reactions of amino acids and peptides with the o-quinones produced by the enzymic oxidation of chlorogenic acid and caffeic acid have been studied manometrically and spectrophotometrically. 2. Amino acids, except lysine and cysteine, react primarily through their alpha-amino groups to give red or brown products. These reactions, which compete with the polymerization of the quinones, are followed by secondary reactions that may absorb oxygen and give products with other colours. 3. The in-amino group of lysine reacts with the o-quinones in a similar way. The thiol group of cysteine reacts with the quinones, without absorbing oxygen, giving colourless products. 4. Peptides containing cysteine react with the o-quinones through their thiol group. 5. Other peptides, such as glycyl-leucine and leucylglycine, react primarily through their alpha-amino group and the overall reaction resembles that of the N-terminal amino acid except that it is quicker. 6. With some peptides, the secondary reactions differ from those that occur between the o-quinones and the N-terminal amino acids. The colours produced from carnosine resemble those produced from histidine rather than those from beta-alanine, and the reactions of prolylalanine with o-quinones are more complex than those of proline.     

Ultra-violet induced mutations to growth factor requirement and penicillin resistance in a blue-green alga

Summary After exposures to UV, two mutant strains of Phormidium mucicola were isolated which are stable and inheritable:1. Strain 5/5 mL-1 is a photoheterotrophic mutant requiring addition of an organic growth factor to the basal medium which appears fulfilled by either casein hydrolysate, glucose, acetate or vitamin mixture and fails to grow heterotrophically.2. mr/p. This strain shows resistance upto 10.24 g/ml of penicillin whereas the parent does not survive beyond a penicillin dose of 0.1 g/ml.     

Ultrastructural differentiation and enzymatic localization of phosphatases in the developing duodenal epithelium of the mouse

Summary The localization of acid and alkaline phosphatase activities during the morphogenesis of the duodenum has been studied at the ultrastructural level in BALB/c mice. The present work deals with the foetal development from the 14th day till birth. It appears that acid phosphatase activity at the 14th day of foetal life, was situated in dense bodies at the base of the intestinal cells. At that moment, the flat apical membrane of the cells lining the intestinal lumen presented a faint alkaline phosphatase activity. With the maturation of the villus cells, the dense bodies migrated to a supra-nuclear zone, and on the 20th day, differentiated into a complex network of dense bodies and dense tubules showing the activity of the two phosphatases. On the other hand, the microvilli were developing from the 16th day, and active pinocytosis appeared on the 18th day. Alkaline phosphatase activity increased rapidly during this differentiation.This study was supported by a research grant no. N.D.G./27 from the Medical Research Council of Canada.The authors are indebted to Mr. Michel Couture for his assistance with the photographs.     

Virucidal Effect of Transient Electric Arcs in Aqueous Systems

Bacterial and animal viruses were inactivated by high voltage electrical discharges in water. The sensitivity of phages to the immediate component of this effect was correlated to the sensitivity to ultraviolet radiation. Transient electrical arcs in weak electrolytes also generated chemical compounds which were virucidal against phages T3, T5, and varphiX174 but were only slightly virucidal against phages T2 and T4.     

Microbiological Evaluation of Pacific Shrimp Processing

Microbiological evaluation of Pacific shrimp (Pandalus jordani) processing was made from samples obtained at five key processing points. The microbial count of raw shrimp ranged from 1.3 x 10(6) to 3.0 x 10(6). The initial microbial flora, in order of predominance, was Acinetobacter-Moraxella, Flavobacterium, Pseudomonas, gram-positive cocci, and Bacillus species. No yeasts were isolated. Differences in processing practices influenced both microbial count and the shrimp flora. The microbial load, however, always increased after peeling and sorting operations and decreased after cooking, washing, and brining steps. Significantly, the gram-positive cocci were recovered with increasing frequency after each processing step, reaching 76% of the total load in a final product. Most of them, however, were coagulase-negative.