Molecular and ultrastructural aspects of the adaptation of Chlamydomonas reinhardtii to limiting CO2

Abstract

INFORMATION TO USERSThis manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, ±ese will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book.Photographs included in the original manuscript have been reproduced xerographicaUy in this copy. Higher quality 6" x 9" black and white photographic prints are available for aiQr photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. 1994Signature was redacted for privacy.Signature was redacted for privacy.Signature was redacted for privacy.ii GENERAL INTRODUCTIONChlamydomonas reinhardtii is a unicellular green alga typically found in the thin films of water on soil particles. The Chlamydomonas life cycle lends itself easily to genetic manipulation and laboratory culture, and Chlamydomonas, therefore, has become an important research model for numerous studies on genetics and cell biology. One such area of study is a COj concentrating system which alters the alga's apparent affinity for CO2 in photosynthesis. Rubisco and the COjtOj RatioCOj concentrating systems impact on the efficiency of photosynthesis because of the interaction between the Calvin cycle of photosynthesis and photorespiration. The first step of the Calvin cycle is the carboxylation of ribulose bis-phosphate to form two 3-phosphoglycerate molecules. 3-Phosphoglycerate is then reduced to form triose phosphates, which are the building blocks for sugars and starches or can be used to regenerate ribulose bis-phosphate for the Calvin cycle. Alternatively, ribulose bis-phosphate can be oxygenated to form one 3-phosphoglycerate molecule, which feeds into the Calvin cycle, and one 2-phosphoglycolate molecule. Two 2-phosphoglycolate molecules can then produce one 3-phosphoglycerate molecule for the Calvin cycle, but in the process, one carbon dioxide molecule and one anmionium ion are lost and ATP is consumed. In addition to a direct energy cost, there is an energy cost to the cell for the loss of carbon, which had already been fixed, as well as nitrogen, which must be re-assimilated at the expense of additional ATP and fairly well understood, a third ...

Regulation of the low-CO2-inducible polypeptides in Chlamydomonas reinhardtii

“…After subcellular fractionation and isolation of intact mitochondria, Eriksson et al (1995) found that the 21-to 22-kDa polypeptide was associated with mitochondria of C. reinhardtii cells. In an independent study, Geraghty and Spalding (1995) also showed by immunogold labelling that LIP-21 is located in mitochondria. However, none of the low-CO2-inducible polypeptides have been linked to a specific function of the CCM (Spalding et al 1991).…”