The aim of this study was to adapt MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay (MCA) (Wang et al., 2010) for determination of lactic acid bacteria cell count. Our study is helpful in developing protocols for measuring the viability of other lactic acid bacteria. We determined the cell concentration range which gives linear regression of CFU (colony forming units) and formazan production. In our experiment three authentic lactic acid bacteria strains were investigated: Lactobacillus rhamnosus VT1, L. plantarum 2142, and L. sakei DSM 2001. As data show beside the strain also the growth medium has influence on the MTT reduction activity, this means that for each special case separate calibration curve has to be prepared. Based on MTT reduction we also developed an improved microtiter plate assay which proved to be reliable for a rapid cell count determination. So our methods are only applicable for estimate cell number with fixed parameters, but under given circumstances they are fast and sensitive methods. With the modified methods we can rapidly measure the dehydrogenase enzyme activity of the lactic acid bacteria cells. With the microplate assay we can measure many conditions and strains at the same time.
Authors:E. Takács, A. Nagy, É. Gelencsér, and A. Székács
Reliable determination of microbial or transgenic Cry toxins is an essential issue in food and feed analyses, and enzyme-linked immunosorbent assays (ELISAs) are the method of choice for quantifying these toxins currently in food and environmental analysis. Internal Quality Control (IQC) is an indispensable method to assess accuracy, precision, and reproducibility of analytical measurements. To assess the utility of the ELISA method, IQC was performed on EnviroLogix Cry1Ab/Cry1Ac QualiPlate ELISA with manufacturer supplied analytical standards. Applicability of negative and positive controls (C− and C+) was examined by Shewhart Control Charts for bias and Control Chart of the Range of Duplicates for precision. Linear regression (up to 5 ng ml−1 Cry1Ab concentration) of the commercial ELISA kit was compared to sigmoid calibration (up to 60 ng ml−1 Cry1Ab concentration). For immunoassay optimization process, possible matrix effects in different liquid and solid vertebrate tissues were examined by determination of the limit of detection values in these matrices.
Authors:Daniel Buček, Martin Orfánus, Peter Dušička, and Peter Šulek
Information Services [ 20 ]. Map of hydraulic roughness is the result of the calibration process ( Fig. 1 ). Sediment transport models can be sensitive to hydraulic roughness, yet bed roughness does not make a good calibration parameter. Therefore, it was
Calibration of Hourly energy simulation using Hourly monitored data and monthly utility records for two case study buildings, Department of Architecture Texas A&M University , Journal Proceedings of Building Simulation , Vol. 9 , 1997 , pp. 411 – 419
Authors:Michaela Červeňanská, Dana Baroková, and Andrej Šoltész
aquifer parameters and hydrologic stresses was performed (model design). During the calibration stage, a set of values for aquifer parameters and stresses, that approximates field-measured heads and flows, was found. A sensitivity analysis, as a part of
Authors:Andrej Šoltész, Dana Baroková, Zinaw Dingetu Shenga, and Michaela Červeňanská
accuracy of groundwater simulation depends on the quality and quantity of input data [ 5 ], it was necessary to obtain different input data to develop the conceptual model. Analysis of the current situation, calibration of the model and prediction of the