Use of an automatic cell-counting system with LED illumination for enumeration of marine bacteria

Abstract

The concentration of aquatic bacteria is basic information required to evaluate the status of environments and to assess bacterial contribution to material cycles. However, the standard direct counting method using epifluorescence microscopy (EFM) is tedious and there is variation in the counts among workers. Here an automatic counting system that consists of Bioplorer (BP) and image analysis has been applied to marine bacteria. BP is composed of a light-emitting diode (LED) illuminant, an optical unit, a driving stage and a charge-coupled device camera. In combination with fluorescent labeling and simplified membrane filtration, bacteria are enumerated automatically. The reproducibility, sensitivity and accuracy of the system were tested for natural marine bacteria, in comparison with EFM and flow cytometry (FCM). The counts obtained by BP showed good correlation with those obtained by EFM and FCM methods. The counts were significantly higher in inshore and oceanic samples, indicating high sensitivity with low background noise. Considering its reproducibility, objectivity, ease of use and compact size, BP can be used as a routine tool for counting aquatic bacteria in substitution for EFM or FCM.

Analysis of bacterial communities in Nannochloropsis sp. cultures used for larval fish production

“…cultures examined in this study ranged 7.72 ¥ 10 5 -2.39 ¥ 10 6 cells/mL (Tables 2 and 3); these values were generally in the same range of bacterial counts in coastal sea waters (from 2.78 ¥ 10 5 to 5.75 ¥ 10 6 cells/mL). 15,17,18 The proportion of DVC positive cells to total bacteria in the Nannochloropsis sp. cultures averaged 46.0%.…”

Automatic counting of FISH-labeled microbes by an LED illuminated detecting apparatus

“…Though there is evidence to demonstrate the usefulness of BP in total count of marine bacteria 15 and viable count in food, 13 little is known about its feasibility for direct detection and identification of bacteria of interest. In this present investigation, the authors examined the applicability of BP to the detection and counting of cells of both eukaryotic and prokaryotic microbes after FISH staining.…”

Rapid Enumeration of Microbial Cells in Solubilized Soymilk Using an Automatic Cell Counting System with LED Illumination

“…Bioplorer is an optical device originally designed to enumerate bacteria in cosmetics, toiletries, and food (Arai et al, 2006;Masakiyo et al, 2010;Nishimura et al, 2006;Nishimura et al, 2008;Shimakita et al, 2006;Shimakita et al, 2007). It is composed of a charge-coupled device camera, an optical unit, a light-emitting diode (LED) light source and a driving stage.…”