Die aerobe Glykolyse der Tumorzelle

A high aerobic glycolysis (aerobic lactate production) is the most significant feature of the energy metabolism of rapidly growing tumor cells. Several mechanisms, which may be different in different cell lines, seem to be involved in this characteristic of energy metabolism of the tumor cell. Changes in the cell membrane leading to increased uptake and utilization of glucose, a high level of fetal types of isoenzymes, a decreased number of mitochondria and a reduced capacity to metabolize pyruvate are some factors which must be taken into consideration. It is not possible to favour one of them at the present time.     

Sibling species or poecilogony in the polychaete<Emphasis Type="Italic"> Scoloplos armiger</Emphasis>?

In marine invertebrates multiple modes of development, or poecilogony, may occur in a single species. However, after close examination, many of such putative cases turned out to be sibling species. A case in point may be the cosmopolitan orbiniid polychaete Scoloplos armiger, which inhabits marine shallow sediments. In addition to the well-known direct, holobenthic development from egg cocoons, pelagic larvae have also been described. Our culture experiments revealed a spatially segregated source of the two developmental modes. All females of an intertidal population produced egg cocoons and no pelagic larvae. All but 2 out of 15 females of an adjacent subtidal population produced pelagic larvae and no egg cocoons. Based on these results we performed a molecular genetic analysis (RAPD-PCR) on three intertidal and four subtidal populations in the North Sea. Selected samples from all sites were analysed also by the AFLP method. We found significantly higher genetic diversity within subtidal than within intertidal populations. This is consistent with a wider dispersal by pelagic larvae and a smaller effective population size when development is holobenthic. Total genetic divergence is not related to distance but to the intertidal/subtidal division. We suggest that S. armiger actually represents two sibling species.