Cultivation in glucose-deprived medium stimulates mitochondrial biogenesis and oxidative metabolism in HepG2 hepatoma cells.

In order to test the hypothesis that an imbalance between energy requirement and energy supply regulates mitochondrial genes and ultimately mitochondrial biogenesis, energy supply was challenged in HepG2 cells by withdrawal of glucose from the culture medium, making the cells exclusively dependent on mitochondrial ATP production. Such cells showed a 2-fold increase of cytochrome c oxidase activity, elevated levels of mitochondrial DNA, mitochondrial DNA encoded mRNAs and proteins, as well as the nuclear encoded mitochondrial transcription factor A. Lactate production was significantly reduced and glutamine was consumed as an alternative substrate for oxidative metabolism.

Excessive tumor-elaborated VEGF and its neutralization define a lethal paraneoplastic syndrome.

Vascular endothelial growth factor (VEGF) is a potent endothelial cell mitogen and key regulator of both physiologic and pathologic (e.g., tumor) angiogenesis.

Histone patterns during early embryogenesis in the euchiuroid Urechis caupo.

Histones were isolated from nuclei of Urechis caupo unfertilized eggs and embryos from early cleavage through gastrula. Polyacrylamide gel electrophoresis showed the presence of a slow migrating H1s fraction in the egg which was replaced by a faster migrating H1 during development. Radioactive labelling showed no synthesis of H1s from fertilization up to gastrula and a high rate of synthesis of H1 relative to the other histones during cleavage and blastula stages.

Ultrastructural studies on spermatogenesis in a sex-ratio-mutant strain of Drosophila simulans.

The aberrant sex-ratio mutation in D. simulans used for this study is a temperature-sensitive autosomal recessive. Homozygous males raised at 16 degrees C produce about 2% of F1, but those raised at 26 degrees C, have a normal sex ratio.