Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Acetabularia”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1970

Intermediates of photosynthesis in Acetabularia mediterranie chloroplasts.

The chloroplast fraction isolated from Acetabularia mediterranie was exposed to (14)CO(2) as NaH(14)CO(3) in light and darkness, and soluble radioactive compounds were analyzed at frequent intervals. The behavior of Calvin cycle intermediates indicates that this cycle was responsible for much of the carbon fixation in the chloroplasts. However, a substantial part of recently fixed carbon was metabolized via glycolic and glyceric acids. Possible pathways for their metabolism are discussed. Some carboxylation of C(3) acids was suggested by the behavior of phosphoenolpyruvate and malate. A number of amino acids were formed. Small amounts of such compounds as citrate, succinate, and fumarate not usually associated with photosynthesis might have been derived from a low level of mitochondrial contamination. About one-third of the carbon fixed in light was present in acid-labile insoluble compounds other than polysaccharides or proteins. Dark fixation of CO(2) was very small compared with photosynthesis.

Autoradiography↗
PubMed1971

The Effect of pH on the Products of Photosynthesis in CO(2) by Chloroplast Preparations from Acetabularia mediterranea.

The effect of pH on the pathways of carbon in photosynthesis was examined in chloroplast preparations from Acetabularia mediterranea. The flow of carbon into a number of photosynthetic intermediates, particularly sucrose, glycine, serine, glycolate, and the insoluble fraction, was strongly influenced by pH. At higher pH a much larger portion of the (14)C entered intermediates of the glycolate pathway. Although maximal apparent photosynthesis occurred at pH 7.6 to 7.7, cytoplasmic pH was found to be 8.0 to 8.4, using indicators. The pattern of distribution of (14)C in intermediates of whole cells was closest to that in chloroplasts at the higher pH range.

Journal Article↗
PubMed1996

kurkku, a Phenotype of Acetabularia acetabulum That Is Arrested in Vegetative Growth, Can Be Rescued with Wild-Type Cytoplasm.

We isolated several spontaneous phenotypes in the giant unicell Acetabularia acetabulum that have vegetative terminal morphologies. Because they arrest in vegetative development, these cell lines are effectively immortalized. However, they had to be rescued before they could be studied via classical genetics because no heterozygotes from the original self-crosses were found, that is, the wild-type siblings yielded only wild-type progeny. We attempted to rescue these phenotypes in three ways: by amputating the cell apex, by "piggybacking" the mutant nucleus through development in a binucleate heterokaryon, and by replacing the abnormal apex with a wild-type apex. We used one of our immortal cell lines, kurkku, which has a terminal phenotype consistent with arrest early in the juvenile phase of vegetative development, as a prototype for these rescue methods. The kurkku phenotype segregated 1:3 in the original self-cross in which it arose as if it were a single, recessive Mendelian trait. Although amputation failed to rescue kurkku, we succeeded in compensating for the defect both in binucleate heterokaryons and in apical grafts to wild-type cells. kurkku was always recovered in the progeny of the self-crosses of these grafts. These unique ways of analyzing vegetative mutants, combined with the ability to then perform classical genetics, may make A. acetabulum a powerful unicellular model system for the study of vegetative phase change in plants.

Journal Article↗
PubMed1970

Acetabularia chloroplast DNA: electron microscopic visualization.

Isolated chloroplasts of Acetabularia mediterranea, lysed by osmotic shock in a protein monolayer, released large amounts of supercoiled DNA. In some cases, the DNA radiated in large loops from centers of organization. The amount of DNA per chloroplast may be similar to that of a bacterium.

Centrifugation, Density Gradient↗
PubMed1976

[Number of whorls and umbel rays in Acetabularia].

It was found in the proposed model of morphogenesis of Acetabularia that the number of whorls N (as well as the number of umbel rays) depends on the degree of mechanical instability of the deforming cell wall (the greater is instability, the higher is the value N). The genetic control of final morphogenetic processes can be realized by setting definite physical conditions and properties. The theoretical estimates of N carried out for different cases agree fairly well with the experimental data obtained.

Cell Count↗