Oxidation of human serum albumin by polyphenol oxidase

Polyphenol oxidase (PPO) oxidizes, due to their tyrosine content, the proteins histone, casein and human serum albumin. These oxidations are inhibited by ascorbate which lowers the redox potential of the medium. Serum albumin in its native state is only moderately oxidized. If, however, prior to oxidation, the albumin is subjected to denaturation, involving unfolding of the chain, the attack by the enzyme is markedly increased. Such denaturation was effected by either the action of dodecyl sulfate or heating to 60°C. The implications of these findings to the problem of senescence are discussed.     

Interactions between Plants and Epiphytic Bacteria Regarding Their Auxin Metabolism VI. The Influence of the Epiphytic Bacteria on the Content of Extractable Auxin in the Plant

Sterile plants of maize, pea, and cucumber contain less auxin (extracted with methanol or ether) than nonsterile ones. The auxin content is restored within one day by reinfecting sterile plants (or only the shoots, with roots and culture medium remaining sterile) with epiphytic bacteria strains able to produce IAA or with soaking water of nonsterile seeds. Reinfection with bacteria, strains unable to produce IAA is ineffective. — The possibility of a bacterial auxin production during methanol extraction was excluded.     

THE KARYOTYPES OF DIPLOID CESPITOSE ZINNIAS: A METHOD AND ANALYSIS

The karyotypes of the three diploid (n = 10) species of the subg. Diplothrix (Zinnia—Compositae) were compared to determine whether there were any demonstrable differences which could then be sought in their polyploid derivatives. Because many of the chromosomes in a set were too similar to distinguish confidently between them, a method of analysis was developed which measures the similarity of whole sets of chromosomes rather than individual ones. The method consists of measuring the distances between graph-plotted vertices representing arm lengths of chromosomes of real or paper hybrids and then comparing these distances by means of U tests with those similarly derived for the “parents.” This procedure obviates the need of attempting to identify morphologues (morphologically similar chromosomes) in a somatic diploid root-tip cell and to equate corresponding pairs of chromosomes from different cells of a single plant or from different species or hybrids. No demonstrable differences in the karyotypes of diploid cespitose zinnias were found. Analysis of previously published data by this method indicated that there has been a general non-objectivity and non-operationalism in the determination of homologous chromosomes, and a general but unwarranted assumption that morphologues are in reality genologues (genetically corresponding chromosomes).     

PERFORATED PEPTIC ULCER—Selective Gastric Resection in Emergency Treatment

In a series of 240 cases of perforated peptic ulcer prior to 1952 there was a total mortality of 17 per cent. This included cases treated conservatively as a planned procedure or because of other morbid conditions and undiagnosed cases, all ending in death.In cases treated by simple suture, mortality was 2.6 per cent for patients under 50 years of age and 17 per cent for those over 50, the rate rising very steeply with each decade over 50.From 1953 through 1959 selective gastric resection was carried out, the operation being done in all cases of perforated gastric ulcers, of chronic duodenal ulcers and of perforations associated with hemorrhage.During this period 303 perforated ulcers were treated, with a mortality of 15.5 per cent. Patients with associated morbid conditions and those admitted moribund and died, or died undiagnosed were again included.In this series also the mortality increased steeply from age 50 onward.Gastric resection was carried out in 148 cases of perforated peptic ulcer with a mortality of 6 per cent. In 105 cases under 60 years of age there were no deaths but in those over 60 the mortality rate was 21.8 per cent. Results in the patients who had resection, as determined after three years of observation, compared favorably with the results in patients who were treated by suture.The mortality of perforated ulcers in females was higher than in males.Emergency gastric resection has a definite place in the treatment of perforated peptic ulcer.