Fritz Berthold

Application of a new high sensitivity luminometer for industrial microbiology and molecular biology

A compact new luminometer (FB12) has been developed based on a 370-630 nm photon counter and measuring chamber that can accommodate a range of sample formats. The FB12 permits measurements as low as 1000 molecules of luciferase in reporter gene assays. Its sensitivity for ATP is limited by reagent background. If ATP assay reagents had no chemical background, 2 fg of ATP could be detected using 3 SD of instrument background as the detection limit. The FB12 has a dynamic range of six decades and operates under its own microprocessor programme or protocol-based PC software that is integrated with Microsoft(R) Excel(R). An injector port above the sample measuring position allows connection of external reagent injectors. Applications are performed using protocols provided with the FB12 or user defined protocols. Examples are presented that illustrate use of the instrument for research and industrial applications.

Luminometer development in the last four decades: recollections of two entrepreneurs

This article, written by two entrepreneurs in luminescence, traces their involvement in the major part of the interconnected innovation and development of luminometers, adenosine triphosphate (ATP) bioluminescence and other technologies from the mid-1970s to 2011 that ushered in much of the field of luminometry as we know it today. Key developments leading to current commercial applications of ATP bioluminescence, luminescence immunoassay, cellular luminescence, reporter gene and other applications are described from the first tube luminometers derived from early luminescence studies using liquid scintillation counting technology to measuring bioluminescence from crude ATP and firefly tail extracts.

Optimization of phagocyte chemiluminescence measurements using microplates and vials

In order to cope with large amounts of samples for chemiluminescence (CL), vials were replaced with microplates. Although various types of plates have been commercially available for quite some time and the free-plate mode is advocated by the producer of the counter, little is known about their impact on the outcome of CL measurements. We tested two different 24-well microplates and six different 96-well microplates in two different luminometers, and results were compared with those achieved with vials. Before these comparative tests, we attempted to optimize measurement conditions. CL sensitivity was highest with luminol concentrations of 0.8-3.3 micromol/L, PMA concentrations of 0.06-80 micromol/L, a pH value of 10 and a temperature of 20 degrees C. An indirect correlation was found between fluid volume and yield in counts: the lower the volume, the higher the counts. With regard to sensitivity and cross-talk, the 96-well Isoplatetrade mark was superior to all other plates tested. While all white plates tested gave acceptable results, usage of the black 96-well plates resulted in an extremely low sensitivity. Plates designed for cell culturing gave even lower counts and a cross-talk of up to 31%. All attempts to reduce cross-talk and improve sensitivity, such as aluminium foil or grids, irrespective of the position of the photomultiplier, did not give results comparable to the original 96-well isoplate. Our results suggest that, with the exception of black 96-well microplates and cell culture plates, all other plates tested have a sufficient sensitivity when compared to vials and acceptable cross-talk, the 96-well Isoplatetrade mark being the best. Both types of luminometers used gave reproducible results, Wallac having a somewhat higher sensitivity, Canberra Packard somewhat less cross-talk.

LUMINOMETERS FOR INDUSTRIAL APPLICATIONS OF RAPID MICROBIOLOGY

FRITZ BERTHOLD,’ KLAUS HAFNER,~ MARTIN SCHREIBERS,3 VEIKKO TARKKANEN4 Berthold Technologies GmbH & Co. KG, Calmbacher Straje 22, 75323 Bad Wildbad, Germany, Email: fritz. berthold@Berthold.com; 3 0 Engineering, Coppistraje 55, 041 57 Leipzig, Germany, Email: hafner@3dengineering.de; Celsis International B. V., Amperestraat 13, 63 72 BB Landgraaf; The Netherlands, Email: mschreibers@celsis.nl; 4503, Chemin Pied Marin 2, 84380 Mazan, France, Email: vt@lumil.com I