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Biomedical subjects

A H Chagla

Publications and source records attributed to A H Chagla.

25 records · Page 2Linked to original sources
PubMed1977

The cytochromes of Acanthamoeba castellanii.

1. Low-temperature difference spectra of gradient-purified mitochondria of Acanthamoeba castellanii reveal the presence of cytochromes b-555, b-562 and c-549, with a-type cytochromes having a broad asymmetrical maximum at 602 nm; these components were also observed in specta of whole cells. 2. The a-type cytochromes are unusual in that they have split Soret absorption maxima (at 442 and 449 nm) and an uncharacteristic CO difference spectrum. 3. CO difference spectra of whole cells and 'microsomal' membranes show large amounts of cytochrome P-420 compared with cytochrome P-450. 4. Difference spectra in the presence of cyanide indicate the presence of an a-type cytochrome and two cyanide-reacting components, one of which may be cytochrome a3. 5. Whole-cell respiration in a N2/O2 (19:1) atmosphere was decreased by 50%, suggesting the presence of a low-affinity oxidase. This lowered respiration is inhibited by 50% by CO, and the inhibition is partially light-reversible; photochemical action spectra suggest that cytochrome a3 contributes to this release of inhibition. Other CO-reacting oxidases are also present. 6. The results are discussed with the view that cytochrome a3 is present in A. castellanii, but its identification in CO difference spectra is obscured by other component(s).

Amoeba↗
PubMed1975

Synchronous cultures of micro-organisms: large-scale preparation by continuous-flow size selection.

The separation of the smallest cells from an exponentially growing culture by passage through a continuous flow centrifuge rotor under controlled conditions of rotor speed and flow rate, provides a simple method for the rapid production of large-scale synchronous cultures. The effluent from the rotor, containing the smallest-sized class of organisms, still suspended in their growth medium and still growing undisturbed throughout this rapid procedure, provides a culture which goes on to exhibit synchronous cell division. Successfully applied to budding and fission yeasts and to amoeboid and ciliated protozoa, this procedure ti potentially applicable to any non-filamentous, non-aggregating, unicellular organism or to cells of higher plants or animals growing in liquid tissue-cultures.

Animals↗