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61.
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Summary Catalase induction in Rhodopseudomonas spheroides and three locally isolated strains of Rhodopseudomonas (TL-1, TL-4 and Rps. D) was studied. A correlation between the rate of excretion of porphyrin and the inducibility of the culture was observed. 8-hydroxyquinoline at 4x10-5 M had no effect on Bchl synthesis but it inhibited porphyrin excretion and catalase induction in Rhodopseudomonas spheroides. 8-OH Q at this concentration partially inhibited Bchl synthesis and catalase induction in strain TL-1. The data indicate that the amount of catalase produced is dependent on the pool size of porphyrins.Abbreviations used ALA
-amino laevulinic acid
- Bchl
Bacteriochlorophyll
- EDTA
Ethylene diamine tetra acetate
- DMSO
Dimethyl sulfoxide
- 8-OH Q
8-hydroxyquinoline
- nm
nanometer
-
Rh.
Rhodopseudomonas
This work is part of a thesis submitted by K. T. Shanmugam in partial fulfillment of the requirements for the Ph. D. degree. 相似文献
63.
The nuclei of Amphiuma contain 168 pg of DNA, 28 times that contained in human nuclei. Although many higher organisms appear to possess an excessive amount of DNA, in Amphiuma this has been carried to the extreme. Studies of this organism thus may provide some insight into how this excess DNA is used. This organism presumably evolved by numerous polyploidy and gene duplication events. Do its gene products present multiple electrophoretic forms? Are they quantitatively increased to the same degree as the DNA? Electrophoresis of Amphiuma glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, acid phosphatase, lactic dehydrogenase, and hemoglobin failed to show any evidence for multiple electrophoretic forms of these respective gene products. The amount of hemoglobin, G6PD, and 6PGD per red cell was increased to a comparable or even greater degree than the DNA. Analytical ultracentrifugation demonstrated a satellite band of DNA with a density of 1.720 corresponding to a GC content of 61%. This probably represents DNA coding for ribosomal RNA. Electron microscopy of liver nuclei showed a significant amount of condensed chromatin. The implications of these observations are discussed. 相似文献
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M. Berger O. Z. Roy J. S. Hart 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1970,66(2):190-200
Summary Investigations in 10 species showed that respiration of birds in flight is usually co-ordinated with wing beats, but the co-ordination is not obligatory. Respiration synchronous with wing beats (11 co-ordination) was found only in pigeons and crows, the other species exhibited one of 11 other types of co-ordination. Quails, ducks and pheasants, birds with relatively high wing beat frequencies (with relatively small wings) showed a 51 co-ordination. Within species, and even during a flight the type of co-ordination changed, and simultaneously there were sudden changes in the respiration frequency. For the most part, the beginning of inspiration was linked with the (end of) upstroke and the beginning of expiration with the end of downstroke.Issued as N.R.C.C. No. 11095Dedicated to Prof. Dr. Erwin Stresemann at his 80. birthday.We are grateful to Dr. D. Jensen for enabling the work on the gulls at McMaster University in Hamilton. We also wish to thank B. A. Mackenzie and R. Charbonneau for the skillful assistance in all experiments. 相似文献
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R L Berger E Antonini M Brunori J Wyman A Rossi-Fanelli 《The Journal of biological chemistry》1967,242(20):4841-4843
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These studies were designed to evaluate the ability of the zona-free hamster ova bioassay to detect differences in fertility of boar sperm. In the first study, sperm from two previously infertile boars were compared to sperm from seven previously fertile boars. The percentage of zona-free hamster ova penetrated by sperm from the previously infertile boars was significantly lower than the percentage of ova penetrated by sperm from previously fertile boars (18% of ova penetrated vs. 83%, P < .001). In the 14 ejaculates from the previously infertile boars that had ejaculate motilities of 50% or greater, the percentage of zona-free hamster ova penetrated continued to be lower than in ejaculates from the fertile boars. One of the two previously infertile boars consistently had a normal semen analysis. The only two observed manifestations of his reduced fertility were his zero conception rate and the limited ability of his sperm to penetrate zona-free hamster ova. In the second study, females were inseminated with equal numbers of sperm from two previously fertile males and the paternity of offspring determined at birth. The experiment was replicated with four combinations of six boars. A high correlation was observed between the percentage of offspring sired and the ability to penetrate zona-free hamster ova (R = .89). Neither morphology nor the ability of the sperm to undergo an acrosome reaction during in vitro incubation was correlated with fertility in the competitive mating situation. These results suggest the zona-free hamster ova bioassay can improve the in vitro fertility assessment of fresh boar semen. 相似文献