Efecto del pH y la salinidad en el crecimiento y luminiscencia de una bacteria marina como biosensor ambiental

Effect of pH and salinity on the growth and luminescence of a marine bacterium as an environmental biosensor Resumen El trabajo se desarrolló en el Centro de Estudios de Proteínas de la Facultad de Biología de la Universidad de La Habana en septiembre de 2012 con el objetivo de evaluar el crecimiento y la luminiscencia de la cepa bacteriana CBM-784 en el medio LM a diferentes intervalos de pH y salinidad y determinar los rangos óptimos para sus crecimiento y luminiscencia. Los resultados demuestran que la bacteria luminiscente CBM-784 mostró su mejor crecimiento y luminiscencia a pH= 8,3 y concentraciones de NaCl entre 2,95 y 3,5%. Palabras clave: bacterias; ecología marina; luciferase; luminiscencia bacteriana; medio de cultivo. Abstract The work was developed at the Center for Protein Studies of the Faculty of Biology of the University of Havana in September 2012 with the objective of evaluating the growth and luminescence of the bacterial strain CBM-784 in the LM medium at different intervals of pH and salinity and to determine the optimal ranges for its growth and luminescence. The results demonstrate that the luminescent bacterium CBM-784 showed its best growth and luminescence at pH = 8.3 and NaCl concentrations between 2.95 and 3.5%. Keywords: bacteria; marine ecology; luciferase; bacterial luminescence; culture medium.

Modelling of the response of acoustic piezoelectric resonators in biosensor applications – Part 1: The general theoretical analysis

Acoustic piezoelectric resonators are widely used as precise analytical chemistry tools for the real-time monitoring of a negligibly small amount of surface-attached mass of biological components, in particular, in environmental biosensor measurements. The surface acoustic wave (SAW)-based sensors and the quartz crystal microbalance (QCM) compared in our work belong to the leading group due to their considerable advantages. These piezoelectric resonators are considered now as high-resolution analytical tools allowing researchers to discriminate between components due to the selective polymer coating on the resonator surface. The gravimetrical measurements performed with the SAW-based or QCM sensors provide the experimental data with high precision for the detection of surface mass for the thin adsorbed layer rigidly attached to the oscillator surface. The new challenge is the analysis of soft and biological materials, where the viscous losses of energy can essentially influence measured characteristics. Modelling is the important part of the analysis allowing researchers to quantify the results of the experiments. The present work provides a general theory of SH-SAW devices probing soft and biological materials. The results are compared with QCM-D operated in liquid media.