Effect of lysogeny on transfection and transfection enhancement in Bacillus subtilis

Strains of Bacillus subtilis 168 lysogenic for bacteriophage phi105 transfer with deoxyribonucleic acid (DNA) isolated from bacteriophage SPO2 at a higher efficiency than non-lysogenic strains. This enhancement of transfection was not the result of recombination between bacteriophages SPO2 and phi105. Superinfection marker rescue increased transfection with DNA from bacteriophage phi105 occurred simultaneously with the addition of the transfecting DNA. Again, this enhancement of transfection was not the result of recombination but rather a protection of the transfecting DNA by the superinfecting bacteriophage. The ability of the superinfecting bacteriophage to protect the transfecting DNA from inactivation was maximal when the bacteria were just becoming competent. Bacteriophage phi1 cannot replicate after the transfection of competent bacteria lacking a functional DNA replication system, whereas bacteriophage phi1 was able to replicate after infection of competent bacteria grown under comparable conditions. These observations support the hypothesis that GAPase and an inducible repair system play an important role in the development of competence.     

The fall in household size and the rise of the primary individual in the United States

The long-term fall in household size in the United States is discussed within the framework of the aging of the population, continuing as the effects of fertility and mortality decline accumulate. Using distributions of households by size from U.S. census data 1790-1970 and a components of change analysis on primary individuals for 1950-1974, household changes are related to demographic change for the periods 1790-1900, 1900-1950, and 1950-1974. Fertility and mortality declines have unambiguous impact on household size until the increases in primary individuals begin. But these, too, have a theoretically interesting, if indirect relationship to population structure.     

Androgen receptor dependent and independent activities of testosterone on hepatic microsomal drug metabolism

Administration of testosterone for 6 days to intact female and castrate male BALB/cJ mice stimulated hepatic microsomal ethylmorphine N-demethylase activity and cytochrome P-450 content by 50-75%. Testosterone also stimulated hepatic microsomal NADPH-oxidase activity, but to a lesser degree. To probe the mechanism of this effect of androgens, two antiandrogens (cyproterone acetate and flutamide) were employed. Since cyproterone acetate was a potent stimulator of hepatic microsomal ethylmorphine N-demethylase activity and cytochrome P-450 content, no antiandrogenic activity of this steroid could be detected. By contrast, flutamide alone had little effect on either ethylmorphine N-demethylase activity or cytochrome P-450 content. However, this drug effectively blocked the stimulatory effects of testosterone on ethylmorphine N-demethylase activity and cytochrome P-450 content but not on NADPH-oxidase activity. This effect was not species specific, since flutamide also prevented androgen stimulation of ethylmorphine metabolism in adult castrate and prepubertal male Fisher rats. The testosterone-induced increase of hepatic weight and microsomal protein content was not affected by the administration of flutamide. The observations are consistent with the hypothesis that androgens have two distinct effects on the liver. First, testosterone may act as a general, nonspecific stimulant of liver weight and microsomal protein content which is independent of the androgen receptor. Secondly, testosterone action in the liver may be expressed via an androgen-specific or androgen receptor-dependent mechanism which controls, in part, the cytochrome P-450-dependent demethylase system.     

Large colon resection

Early motor manifestations are the main components of focal seizures involving the frontal lobe. We examined the relationship between the initial ictal motor manifestations and interictal abnormalities of cerebral glucose consumption (rCMRGlc) as assessed by PET in 48 consecutive patients with focal seizures of neocortical origin. Group data analysis revealed that patients with predominantly unilateral clonic seizures had a significant contralateral perirolandic hypometabolism and to a lesser degree a contralateral frontomesial hypometabolism. Patients with predominantly focal tonic manifestations showed a hypometabolism within the frontomesial and perirolandic regions that was unilateral in all patients with lateralized tonic seizures. Patients with versive seizures had mainly contralateral metabolic depressions without a consistent regional pattern. Patients with hypermotor seizures had metabolic depressions involving frontomesial, anterior cingulate, perirolandic, and anterior insular/frontal operculum areas. In all patient groups, bilateral and symmetric hypometabolism of the thalamus and cerebellum was observed. We propose that this pattern of distinctly abnormal metabolic brain regions demonstrates not only possible epileptogenic zones but also symptomatogenic brain regions as shown by the associations between clinical manifestations and sets of abnormal brain regions, particularly if epileptogenic zones are in a clinically silent neocortical brain region. The detection and possible differentiation of symptomatogenic and epileptogenic zones might improve the effectiveness of presurgical noninvasive studies.     

Movement and distribution of fertilizer nitrogen as affected by depth of placement in wetland rice

Experiments were conducted to monitor the movement and distribution of ammonium-N after placement of urea and ammonium sulfate supergranules at 5, 7.5, 10, and 15 cm. By varying depths of fertilizer placement, it is possible to determine the appropriate depth for placement machines. There were no significant differences in grain yields with nitrogen placed 5 and 15 cm deep. However, grain yields were significantly higher with deep placement of nitrogen than with split application of the fertilizer. The lower yields with split-applied nitrogen were due to higher nitrogen losses from the floodwater. The floodwater with split application had 78–98µg N ml^–1 and that with deep-placed nitrogen had a negligible nitrogen concentration.Movement of NH ₄ ⁺ -N in the soil was traced for various depths after fertilizer nitrogen application. The general movement after deep-placement of the ammonium sulfate supergranules was downward > lateral > upward from the placement site. Downward movement was prevalent in the dry season: fertilizer placed at 5–7.5 cm produced a peak of NH ₄ ⁺ -N concentration at 8–12 cm soil depth; with placement at 15 cm, the fertilizer moved to 12–20 cm soil depth. Fertilizer placed at 10 cm tended to be stable. In the wet season, deep-placed N fertilizer was fairly stable and downward movement was minimal.A substantially greater percentage of plant N was derived from¹⁵N-depleted fertilizer when deep-placed in the reduced soil layer than that applied in split doses. The percent N recovery with different placement depths, however, did not vary from each other. The results suggest that nitrogen placement at a 5-cm soil depth is adequate for high rice yields in a clayey soil with good water control. In farmers' fields where soil and water conditions are often less than ideal, however, it is desirable to place nitrogen fertilizer at greater depths and minimize NH ₄ ⁺ -N concentration in floodwater.