Vergleichende Untersuchungen an HNO2-Inaktivierten und UV-Inaktivierten Bakteriophagen T4

Summary The inactivation of phage T4 by nitrous acid (HNO₂) is essentially an exponential function of time of treatment. HNO₂-inactivated T4 is able to undergo multiplicity reactivation, and genetic markers may be rescued by live phage, however, the extent of both effects is appreciably less than after UV-inactivation. Also, the survival of phenotypic function of the cistronsr II-A andr II-B is lower with HNO₂-treatment than with a UV-irradiation of a corresponding number of hits.The reduced effects are quantitatively accounted for by the assumption of lethal hits blocking early steps of infection. These early-step damages amount to approximately 1/6 of the total hit number; it is still unknown whether they occur in DNA or in protein. Some indication for the occurrence in protein comes from the result that the host-killing efficiency of HNO₂-inactivated phage is reduced at a similar rate as these early-step damages occur. However, at least 5/6 of the lethal hits are due to chemical changes within the DNA, as can be calculated from the results of multiplicity reactivation, marker rescue, and phenotypic survival of therII-cistrons.

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Influence of Inorganic Phosphorus on Oxytetracycline Formation by Streptomyces rimosus

Production of oxytetracycline by Streptomyces rimosus in several chemically defined media containing graded concentrations of inorganic phosphorus was studied in shake flasks. Although high levels of inorganic phosphate have been reported to inhibit oxytetracycline formation, this study indicated that composition of the medium is an important factor in determining whether antibiotic production will be stimulated or inhibited by specific concentrations of inorganic phosphate.     

Characterization of Clostridium perfringens (welchii) Isolated from Market Poultry

Strains of Clostridium perfringens capable of producing heat-resistant spores, characteristic of the food-poisoning types, were not recovered in a random survey of feces and livers of market poultry. Favorable growth response with a known food-poisoning strain indicated that the media and methods employed were adequate. Spores produced in vitro from this strain survived at 100 C for several hours. Animal feeding experiments with this strain showed that heat-resistant spores (surviving for 1 hr at 100 C) could be readily demonstrated 24 hr after oral instillation of vegetative cells in mouse feces, but not in chicken feces. One experiment suggests that this strain might adapt to the environment of the intestinal tract of chickens, but not all of the spores recovered were as heat resistant as those of the parent culture.     

Dimensional analysis in mathematical biology I. General discussion

Dimensional analysis is discussed from the viewpoint of its basic group properties and shown to be an algebraic Abelian group that is useful for analysis of physical measurements. The application of the method to various types of equations and the formulation of previously unclassified dimensions are discussed. Functional dimensional analysis is applied to the problems of cell size and biomass proliferation; future applications are also noted. A number of dimensionless terms have been formulated for cellular physiochemical phenomena. They apparently represent the first systematic study of biological dimensionless numbers recorded in the literature. A dimensionless proliferation law is suggested. A brief analysis of the physical dimensionality associated with information measures is carried out. Entropy and “information” are shown to be completely different in their dimensional meaning; other informational measures of possible interest in biology are proposed. The dimensional coding and computor analysis of biomathematical equations is suggested.     

An Electron Microscope Study of Intranuclear Inclusions in Mouse Liver and Hepatoma

An electron microscope study of intranuclear inclusions which occur in giant cells in a transplantable mouse hepatoma and in enlarged liver cells in mice fed a diet containing bentonite demonstrates that these inclusions are formed by invaginations of the nuclear envelope, and corroborates a previous histochemical study which revealed that the contents of the inclusions are of cytoplasmic origin. In the hepatoma cells the intranuclear inclusions are abundant, small, and situated close to the border of the nucleus, and there are wide openings from the cytoplasm into the invaginations whose contents include lipid droplets, ergastoplasm, and structurally normal mitochondria. In the enlarged liver cells the inclusions are fewer in number, generally much larger than those in the hepatoma, hence they extend deeper into the nucleus, and the interior is continuous with the cytoplasm through only a small opening. Some normal ergastoplasm is present within the inclusions but all other constituents are abnormal. Both normal and degenerating mitochondria occur in the cytoplasm but only degenerating ones are found within the inclusions. Both types of inclusions arise in greatly enlarged cells in which an attempt is made to maintain the normal nuclear surface/nuclear volume ratio by the development of the invaginations of the nuclear envelope.     

ACUTE AND CHRONIC ASTHMA—Treatment with Theophylline in Hydro-Alcoholic Solution: Clinical Evaluation and Pulmonary Function Studies

A flavored solution containing 80 mg. of theophylline and 3 cc. of ethyl alcohol per 15 cc. was given orally to 31 patients with acute asthma to terminate the attack. Thirty patients with moderate to severe chronic asthma were alternated for three or four weeks on daily multiple doses of either the theophylline solution or a placebo.In the acute cases three-second Vital Capacity increased by 33.8 per cent and Maximal Breathing Capacity by 30.2 per cent in one hour after taking 60 cc. to 75 cc. of the theophylline solution. When placebos were given, both measures of lung function declined during the first half hour.Seventy-one and a half per cent of patients with acute cases felt moderate to complete relief of symptoms. In persons with chronic asthma the regular use of the theophylline solution did not change the frequency of asthma in most cases, but it decreased the severity in 59 per cent of cases. The values for three-second Vital Capacity and Maximal Breathing Capacity rose only a little.Gastric irritation was noted in one-third of the chronic cases and one-fourth of the acute cases. This could be reduced by appropriate measures.