Rapid Characterization of Bacteria Using ClairScope™ and SpiralTOF™
In many fields such as clinical diagnosis and food inspection, there is a demand for rapid, reliable and simple-to-use methods for characterizing bacteria. This paper explores the use of two new and innovative instruments called ClairScope™ and SpiralTOF™ for this rapid characterization. The JASM-6200 ClairScope™ integrates an optical microscope (OM) with a scanning electron microscope (SEM) where it is possible to observe samples in solution, in an open system, by the SEM at atmospheric pressure. This type of sample would typically require extensive sample pretreatment that would take a day or more with conventional SEM techniques. With the recently developed ClairScope™, fine morphological observation can be performed directly in solution with simple sample pretreatment of one hour or less. The JMS-S3000 SpiralTOF™, is a matrix-assisted laser desorption/ionization mass spectrometer (MALDI-MS) with a spiral ion trajectory. With sample pretreatment as fast as a few minutes, the SpiralTOF™ can characterize ribosomal proteins and phospholipids with high accuracy. Ribosomal proteins are biomarkers for phylogenetic classification, and phospholipids are used for chemotaxonomic analysis. The combination of ClairScope™ and SpiralTOF™ are found to be powerful instruments for the characterization of bacteria.
Introduction
Rapid characterization methods are in demand for bacteria, which are simple to use and reliable, in a variety of fields such as clinical diagnosis, food inspection, and in environmental energy industries. Bacterial characterization methods can be divided into two categories: analysis of phenotype and genotype. Phenotype analysis includes a morphological study and chemotaxonomy where analysis of bacterial cell components such as proteins and lipids are analyzed. Genotype analysis includes gel electrophoresis and DNA sequencing using a sequencer.
In many cases, a skilled operator can identify the species of bacteria using an optical microscope combined with supplemental information. However, optical microscope (OM) has limited resolution and with bacterial size typically smaller than a few micrometers, detailed structural information cannot be obtained. The use of scanning electron microscope (SEM) overcomes this resolution limitation but often requires long sample pretreatment such as dehydration and fixation that can take a day or even longer.