513 research outputs found
The Strange Case: The Unsymmetric Cisplatin-Based Pt(IV) Prodrug [Pt(CH3COO)Cl2(NH3)2(OH)] Exhibits Higher Cytotoxic Activity with respect to Its Symmetric Congeners due to Carrier-Mediated Cellular Uptake
The biological behavior of the axially unsymmetric antitumor prodrug (OC-6-44)-acetatodiamminedichloridohydroxidoplatinum(IV), 2, was deeply investigated and compared with that of analogous symmetric Pt(IV) complexes, namely, dihydroxido 1 and diacetato 3, which have a similar structure. The complexes were tested on a panel of human tumor cell lines. Complex 2 showed an anomalous higher cytotoxicity (similar to that of cisplatin) with respect to their analogues 1 and 3. Their reduction potentials, reduction kinetics, lipophilicity, and membrane affinity are compared. Cellular uptake and DNA platination of Pt(IV) complexes were deeply investigated in the sensitive A2780 human ovarian cancer cell line and in the corresponding resistant A2780cisR subline. The unexpected activity of 2 appears to be related to its peculiar cellular accumulation and not to a different rate of reduction or a different efficacy in DNA platination and/or efficiency in apoptosis induction. Although the exact mechanism of cell uptake is not fully deciphered, a series of naive experiments indicates an energy-dependent, carrier-mediated transport: the organic cation transporters (OCTs) are the likely proteins involved
Effect of Xylanase on the Technological Behaviour of Wheat Flours
The objective of this work is to investigate the effect of enzyme xylanase on the technological behaviour of wheat flours, particularly in alveograms and bread making, using two flour qualities and two bread making methods. The enzyme used was xylanase from Bacillus subtilis which is sold for mainly for baking applications. Breads were made applying both the French and the pan bread methods. Experts scored the external and internal characteristics of breads. Increase in enzyme concentration produced a decrease in maximum pressure (P) and tensile strength/extensibility (P/L) but deformation energy (W) remained almost constant in the alveogram. This means that the water released by the hydrolysis of insoluble pentosans has reduced the tenacity of the dough. The higher the enzyme concentration, the lower the dough consistency during kneading. Besides, the greatest improvement of quality was produced when xylanase was added to low quality flour and when the French type bread making method was applied.Fil: Osella, C.. Universidad Nacional del Litoral. Facultad de IngenierĂa QuĂmica. Instituto de TecnologĂa de Los Alimentos; ArgentinaFil: de la Torre, M. A. G.. Universidad Nacional del Litoral. Facultad de IngenierĂa QuĂmica. Instituto de TecnologĂa de Los Alimentos; ArgentinaFil: Erben, Melina. Universidad Nacional del Litoral. Facultad de IngenierĂa QuĂmica. Instituto de TecnologĂa de Los Alimentos; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Santa Fe; ArgentinaFil: Gallardo, A.. Universidad Nacional del Litoral. Facultad de IngenierĂa QuĂmica. Instituto de TecnologĂa de Los Alimentos; ArgentinaFil: Sanchez, H.. Universidad Nacional del Litoral. Facultad de IngenierĂa QuĂmica. Instituto de TecnologĂa de Los Alimentos; Argentin
Concurrent processes set E. coli cell division
A cell can divide only upon completion of chromosome segregation; otherwise, its daughters would lose genetic material. However, we do not know whether the partitioning of chromosomes is the key event for the decision to divide. We show how key trends in single-cell data reject the classic idea of replication-segregation as the rate-limiting process for cell division. Instead, the data agree with a model where two concurrent processes (setting replication initiation and interdivision time) set cell division on competing time scales. During each cell cycle, division is set by the slowest process (an "AND" gate). The concept of transitions between cell cycle stages as decisional processes integrating multiple inputs instead of cascading from orchestrated steps can affect the way we think of the cell cycle in general
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