Abstract
Live sporangiophores of Phycomyces blakesleeanus were centrifuged at 35,000 rpm. The cell contents sedimented into distinct layers, and each layer was studied with an electron microscope and with cytochemical methods. The following layers were found (their volumes and their densities are shown in Fig. 3): 1. polyphosphates; 2. polyphosphates and protein crystals; 3. glycogen; 4. yellow layer with ferritin; 5. ribosomes; 6. protein crystals; 7. mitochondria; 8. mitochondria and fibrils; 9. nuclei; 10. endoplasmic reticulum; 11. vesicles, membranes, and reticulum; 12. vacuole; 13. lipoproteins, membranes; 14. fat droplet. The densities of the various layers were determined by the injection of droplets of inert oils of known density into the sporangiosphores before centrifugation. Sedimented cell organelles could be isolated. Centrifuged nuclei of a lycopene-producing mutant were injected into the intact sporangiophore of an albino host where they induced color formation. The ensuing spores, when plated, gave a mixture of white and colored colonies. It was concluded that cell organelles, sedimented by centrifugation of living sporangiophores, remain alive and can be used for biochemical studies. Microspectrophotometric examination of the layers indicated the presence of cytochromes and flavines in the mitochondria and of cytochromes in the nuclei. No pigments corresponding to the action spectrum for the light growth response were found.
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Selected References
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- Delbrück M., Shropshire W. Action and Transmission Spectra of Phycomyces. Plant Physiol. 1960 Mar;35(2):194–204. doi: 10.1104/pp.35.2.194. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heisenberg M., Cerdá-Olmedo E. Segregation of heterokaryons in the asexual cycle of Phycomyces. Mol Gen Genet. 1968;102(3):187–195. doi: 10.1007/BF00385973. [DOI] [PubMed] [Google Scholar]
- LUCK D. J. Genesis of mitochondria in neurospora crassa. Proc Natl Acad Sci U S A. 1963 Feb 15;49:233–240. doi: 10.1073/pnas.49.2.233. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meissner G., Delbruck M. Carotenes and retinal in Phycomyces mutants. Plant Physiol. 1968 Aug;43(8):1279–1283. doi: 10.1104/pp.43.8.1279. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tamir H., Gilvarg C. Density gradient centrifugation for the separation of sporulating forms of bacteria. J Biol Chem. 1966 Mar 10;241(5):1085–1090. [PubMed] [Google Scholar]
- Thornton R. M. The fine structure of Phycomyces. 1. Autophagic vesicles. J Ultrastruct Res. 1967 Dec 12;21(3):269–280. doi: 10.1016/s0022-5320(67)80096-0. [DOI] [PubMed] [Google Scholar]
- Thornton R. M., Thimann K. V. ON A CRYSTAL-CONTAINING BODY IN CELLS OF THE OAT COLEOPTILE. J Cell Biol. 1964 Feb 1;20(2):345–350. doi: 10.1083/jcb.20.2.345. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ZALOKAR M. Sites of protein and ribonucleic acid synthesis in the cell. Exp Cell Res. 1960 Apr;19:559–576. doi: 10.1016/0014-4827(60)90064-1. [DOI] [PubMed] [Google Scholar]
- Zankel K. L., Burke P. V., Delbrück M. Absorption and screening in Phycomyces. J Gen Physiol. 1967 Aug;50(7):1893–1906. doi: 10.1085/jgp.50.7.1893. [DOI] [PMC free article] [PubMed] [Google Scholar]