This study describes the phosphorylatlon efficiency and ATPase activity of brown adipose mitochondria from the hibernating gland of newborn rabbits and from cold-acclimated rats. The data indicate that these mitochond...
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This study describes the phosphorylatlon efficiency and ATPase activity of brown adipose mitochondria from the hibernating gland of newborn rabbits and from cold-acclimated rats. The data indicate that these mitochondria are capable of oxidative phosphorylatlon with a P:O ratio comparable to that of other tissues. However, large amounts of defatted albumin had to be added indicating the presence of uncoupling agents in these preparations. It appears likely that the mitochondria contain long-chain fatty acids which are known to be uncouplers.
Stimulation of the binding of aminoacyl-tRNA to ribosomes was studied using ribopolynucleotide containing formycin (f). Poly (fC) stimulated the binding of [ 14 C]His-tRNA about 50% as much as poly (AC). The bindi...
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Stimulation of the binding of aminoacyl-tRNA to ribosomes was studied using ribopolynucleotide containing formycin (f). Poly (fC) stimulated the binding of [ 14 C]His-tRNA about 50% as much as poly (AC). The binding of [ 14 C]Thr-tRNA was stimulated almost equally by poly (AC) and poly (fC). In the protein synthesizing systems of Escherichia coli in vitro , poly (fC) directed the synthesis of poly (His-Thr) and poly (fG) directed poly (ArgGlu) synthesis. No mistranslation was observed. T m of poly (fU) was slightly lower than that of poly (AU).
The β-γ circular polarization correlation in the decay of 46 Sc has been measured by means offorward Compton scattering. In addition to usual corrections that are applied to the data, the effect of transmission thr...
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The β-γ circular polarization correlation in the decay of 46 Sc has been measured by means offorward Compton scattering. In addition to usual corrections that are applied to the data, the effect of transmission through the central lead stopper and scattering from coils etc. have been investigated. The effect of different source backings has also been studied. The value of the asymmetry parameter A in the β-γ circular polarization correlation was found to be A = 0.13±0.02. This implies a ratio X = −0.064±0.030 between fermi and Gamow-Teller contributions.
The antibiotic formycin (f), an adenosine anlog, was chemically phosphorylated to give formycin 5′-triphosphate (fTP). fTP was tested as a substrate in the Escherichia coli RNA polymerase system using either deoxypol...
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The antibiotic formycin (f), an adenosine anlog, was chemically phosphorylated to give formycin 5′-triphosphate (fTP). fTP was tested as a substrate in the Escherichia coli RNA polymerase system using either deoxypolynucleotides with defined nucleotide sequences or natural DNA's as template. fTP could replace ATP when DNA's from calf thymus, salmon sperm, T 2 and E. coli were used as template. However, the rate of synthesis offormycin-containing RNA was 47–68% of that of RNA from natural nucleoside triphosphates. When the deoxypolynucleotides such as poly d(A-T), poly (T-C) · d(A-G) and poly (T-G) · d(A-C) were used as templates, efficiency of synthesis of poly (f-U), poly (f-G) and poly (f-C) was 56, 94 and 67%, respectively, as compared to the synthesis of the corresponding poly (A-U), poly (A-G) and poly (A-C). This indicates that utilization offTP as an ATP analog is affected by the base sequence of the template. The fidelity of the incorporation offTP in place of ATP was confirmed by the analysis of the digest of the newly synthesized poly (f-U), poly (f-C) and poly (f-G) with bovine pancreatic or T 1 ribonuclease. f p U p , f p C p and f p G p were the sole products from the digest of poly (f-U), poly (f-C) and poly (f-G) respectively.
The chromosome-breaking ability of the monofunctional nitrogen mustard derivative of acridine, 2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamine]acridine dihydrochloride (ICR-170), on chromosomes of Vicia ...
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The chromosome-breaking ability of the monofunctional nitrogen mustard derivative of acridine, 2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamine]acridine dihydrochloride (ICR-170), on chromosomes of Vicia faba has been demonstrated. It is concluded that chromatid-type aberrations are induced in cells in G1, S and G2 and subchromatid type of aberrations in cells in prophase in the 1st mitosis (T1) after treatment, and that chromosome-type aberrations recovered after ICR-170 treatment are not from G1 cells of T1 mitosis but are products in T2 mitosis of duplication of chromatid-type aberrations of T1 mitosis. The action of the monofunctional alkylating component of the ICR-170 molecule seems to play a predominant role in aberration induction.
The bacteriocidal action of Mitomycin C has been investigated with respect to its biochemical, genetic and morphological correlates. All findings are consistent with the observation that cells treated with Mitomycin l...
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The bacteriocidal action of Mitomycin C has been investigated with respect to its biochemical, genetic and morphological correlates. All findings are consistent with the observation that cells treated with Mitomycin lose DNA, but not RNA or protein, to the surrounding medium. Substantial proportions of DNA thymine appear in acid-soluble form, largely as the free base. Mitomycin attacks growing as well as non-growing cells. It may be used for concentrating non-lysogenic cells in lysogenic populations, but not for the preferential selection of biochemical mutants.
from the wild type Escherichia coli B a radiation-resistant and a radiation-sensitive mutant were isolated. Ultraviolet light survival curves for these newly isolated strains resemble those given by other authors for ...
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from the wild type Escherichia coli B a radiation-resistant and a radiation-sensitive mutant were isolated. Ultraviolet light survival curves for these newly isolated strains resemble those given by other authors for E. coli B/r and E. coli Bs respectively. It was proved by biochemical methods that the differences among the three strains are due to two independent mutations, one leading to loss of the tendency to form filaments after various treatments and the other leading to a strong inhibition of growth, nucleic acid and protein synthesis after irradiation with ultraviolet light. X-ray, ultraviolet light, P32 decay and nitrous acid survival curves for the strains are presented. Moreover, survival curves are given for a fourth strain which bears both independent mutations. Procedures are described for screening large numbers of strains arising from conjugation experiments for both types of mutation. Conjugation experiments between f+ and f" auxotrophic mutants were performed. These suggest that both mutations are chromosomally determined.
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