Increased growth capacity of cervical‐carcinoma cells over‐expressing manganous superoxide dismutase

Increases in the expression of manganese‐dependent superoxide dismutase (MnSOD) have been detected in several classes of human and experimental tumors and appear to correlate with poorer prognosis in human neuro‐epithelial, ovarian and cervical tumors. To delineate the relevance of MnSOD expression to tumor‐cell growth and survival, a human MnSOD cDNA was over‐expressed in the HeLa cervical‐carcinoma cell line. MnSOD over‐expression had marginal effects on the growth of HeLa cells in standard medium, but markedly protected the cells from growth suppression and cell death in conditions of serum deprivation. Serum starvation did not affect expression of endogenous MnSOD in wild‐type HeLa cells, but was associated with increases in cell death and in the generation of intracellular oxygen radicals. By contrast, in HT29 colon‐carcinoma cells, which are relatively resistant to growth‐factor withdrawal, serum deprivation was associated with increases in MnSOD expression and activity. Together these observations suggest that MnSOD provides a mechanism for counteracting the intracellular oxidative processes that impair cell growth and viability in the context of growth‐factor withdrawal and, in this context, may promote tumor‐cell survival in vivo in conditions normally unfavorable to cell growth. Int. J. Cancer 82:145–150, 1999. © 1999 Wiley‐Liss, Inc

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and Bayesian phylogenetic analysis to characterize Candida clinical isolates

Clinical Candida isolates from two different hospitals in Rome were identified and clustered by MALDI-TOF MS system and their origin and evolution estimated by Bayesian phylogenetic analysis. The different species of Candida were correctly identified and clustered separately, confirming the ability of these techniques to discriminate between different Candida species. Focusing MALDI-TOF analysis on a single Candida species, Candida albicans and Candida parapsilosis strains clustered differently for hospital setting as well as for period of isolation than Candida glabrata and Candida tropicalis isolates. The evolutionary rates of C. albicans and C. parapsilosis (1.93×10(-2) and 1.17×10(-2)substitutions/site/year, respectively) were in agreement with a higher rate of mutation of these species, even in a narrow period, than what was observed in C. glabrata and C. tropicalis strains (6.99×10(-4) and 7.52×10(-3)substitutions/site/year, respectively). C. albicans resulted as the species with the highest between and within clades genetic distance values in agreement with the temporal-related clustering found by MALDI-TOF and the high evolutionary rate 1.93×10(-2)substitutions/site/year