Respiration and Phosphorylation of Mitochondria from Normal and Crown-Gall Tissue Cultures of Tomato

On the origin of cancer metastasis

Metastasis involves the spread of cancer cells from the primary tumor to surrounding tissues and to distant organs and is the primary cause of cancer morbidity and mortality. In order to complete the metastatic cascade, cancer cells must detach from the primary tumor, intravasate into the circulatory and lymphatic systems, evade immune attack, extravasate at distant capillary beds, and invade and proliferate in distant organs. Currently, several hypotheses have been advanced to explain the origin of cancer metastasis. These involve an epithelial mesenchymal transition, an accumulation of mutations in stem cells, a macrophage facilitation process, and a macrophage origin involving either transformation or fusion hybridization with neoplastic cells. Many of the properties of metastatic cancer cells are also seen in normal macrophages. A macrophage origin of metastasis can also explain the long-standing "seed and soil" hypothesis and the absence of metastasis in plant cancers. The view of metastasis as a macrophage metabolic disease can provide novel insight for therapeutic management.

Respiratory Control: Loss in Mitochondria from Diseased Plants

Mitochondria from healthy oat seedlings oxidized succinate with good respiratory control and high ratios of adenosine diphosphate to oxygen. After treatment with victorin, the pathotoxin responsible for symptoms of Victoria blight of oats, susceptible seedlings yielded mitochondria with little respiratory control and lower ratios of adenosine diphosphate to oxygen. No such effects were obtained with victorin-treated resistant seedlings or when victorin was added directly to mitochondria from healthy susceptible or resistant plants. These data indicate that victorin-induced disease results in a reduction in efficiency of the energy-generating system of isolated mitochondria.

Use of Pectinase in Preparation of Mitochondria from Tobacco-Tissue Cultures

Mitochondrial particles were isolated from tobacco cells in tissue cultures which were disintegrated with pectinase. The pectinase treatment of the tissue cultures reduced the dry weight of the particulate preparations and eliminated glutinous material, but caused little change in oxidative and phosphorylative activities. The pectinase apparently did not affect the enzymatically active sites of the particles.