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D A Roncari

Publications and source records attributed to D A Roncari.

74 records · Page 5Linked to original sources
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Accumulation of starch in Chlamydomonas reinhardtii flagellar mutants.

Paralyzed flagellar mutants pf-1, pf-2, pf-7, and pf-18 of the green alga Chlamydomonas reinhardtii (Dangeard) were shown to store a significantly greater amount of starch than the motile wild type 137c+. The increase in starch storage was significant relative to protein, chlorophyll, and cell number. Analysis of average cell size revealed that the paralyzed mutants were larger than the wild type. This increase in storage molecule accumulation supports an inverse relationship between chemical energy storage and energy utilization for biomechanical/motile cellular functions. Chlamydomonas reinhardtii provides a useful model for studies of the role of cytoskeletal activity in the energy relationship and balance of organisms.

Animals↗
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Decreasing expression of a gene encoding a protein related to basic fibroblast growth factor during differentiation of human preadipocytes.

Pursuant to our findings that pituitary basic fibroblast growth factor (bFGF) stimulates the replication of preadipocytes and inhibits their differentiation, we have studied the changes in expression of a bFGF-related mRNA during differentiation. Human omental preadipocytes were grown in primary culture and induced to differentiate with chemically defined serum-free medium. The differentiation process was assessed by monitoring the rise of glycerophosphate dehydrogenase (GPDH) activity, while mRNA expression for a bFGF-related protein(s) and GPDH was examined by amplifying the respective target sequences by polymerase chain reaction. In the case of all cell strains, differentiated preadipocytes revealed much lower expression of bFGF-related mRNA than undifferentiated preadipocytes. Concurrently, the expression of the GPDH mRNA rose significantly. The finding that the expression of the bFGF-related protein is decreased appreciably during adipose differentiation is consonant with its proposed function to expand and maintain adipose cells in a relatively undifferentiated state.

Adipocytes↗