DNA distribution pattern in intestinal carcinoid tumors.
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Adult↗
Biomedical subjects
G Cohn
Publications and source records attributed to G Cohn.
DNA metabolism during infection of Anacystis nidulans by cyanophage AS-1. VI. Effect of hydroxyurea and nalidixic acid on the development of cyanophage AS-1.
The use of the DNA inhibitors hydroxyurea (HU) and nalidixic acid (NAL) to elucidate patterns of DNA metabolism in AS-1 infected A. nidulans have led to several conclusions. First, HU and NAL at concentrations of 500 and 100 micrograms/ml, respectively, inhibited DNA synthesis in synchronized A. nidulans. Protein and chlorophyll synthesis remained essentially unchanged as did turbidity increases. Second, the complete burst size of the cyanophage AS-1 was severely affected by HU and NAL treatment and burst sizes of 8 and 2.6, respectively, were obtained. Third, inhibitor treatment of infected cultures caused a premature release of phage at 12 h instead of 16 h post infection. Finally, HU treatment of the host cell had no effect on the formation of PIL-DNA, whereas NAL pretreatment blocked its formation.
Chlorophyll↗
DNA metabolism during infection of Anacystis nidulans by cyanophage AS-1. VII. UV-induced alterations of the AS-1/A. nidulans lytic cycle.
In order to interfere specifically with either the host of phage DNA metabolism and separate the effects of new phage DNA synthesis from the effects of host cell breakdown and PIL-DNA formation, UV irradiation of either the host, A. nidulans, or intact phage AS-1, prior to infection was utilized. Several conclusions were reached. First, a photoreactivation system was present in UV-irradiated A. nidulans. Second, the complete burst size of AS-1 was severely affected by UV irradiation of cells and/or phage; third, UV treatment of cells infected with healthy phage caused an early release of phage at 12 h instead of 16 h post-infection; however, healthy cells infected with UV-irradiated phage caused a delayed release of phage as 20 h.
Cyanobacteria↗
Effect of large amounts of vitamin E during pregnancy and lactation.
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Animals↗
Electron spinal resonance analysis of the nitroxide spin label 2,2,6,6-tetramethylpipidone-N-oxyl (Tempone) in single crystals of the reduced Tempone matrix.
The nitroxide spin label Tempone (2,2,6,6-tetramethylpiperidone-N-oxyl) can be reduced with ascorbic acid to give a nonparamagnetic species. Single crystals of reduced Tempone serve as a suitable host matrix to orient trace quantities of Tempone for ESR analysis. In these crystals the majority of the Tempone molecules are well-oriented, but a smaller fraction of the molecules tumble freely to give an isotropic electron spin resonance (ESR) spectrum. ESR transitions for the oriented molecules are saturated at much lower microwave power levels than for the tumbling molecules. For the oriented molecules, an analysis of the anisotropy of the spectroscopic splitting factor (g) gives principal values of g(1) = 2.0094, g(2) = 2.0061, g(3) = 2.0021. The hyperfine coupling tensor is nearly axially symmetric, with principal values (in gauss) of A(1) = 6.5, A(2) = 6.7, A(3) = 33.0. Within experimental error, the principal axis systems for the g tensor and the hyperfine tensor are identical. Comparison of the average values of g and A with the isotropic values of these parameters for Tempone in solvents of different polarity suggests a method for choosing the most appropriate tensor elements to be used for spin label experiments in various solvent systems.
Crystallization↗