Are you using microscopy to monitor phytoplankton or filamentous fungi?

07.11.2017  by  Lucyna Wlodarczyk

Cell densities measured by microscopy vs. the CytoSense. The methods give comparable results for microphytoplankton (> 20 μm; a) and nanophytoplankton (5−20 μm; b). Cell densities of picophytoplankton (< 5 μm; c) are higher when measured with the CytoSense. / Source: figure 4 in Haraguchi et al., Aquat. Microb. Ecol. 2017

Biovolume determined by microscopy vs. the CytoSub. The methods give comparable results for ciliate (A) and dinoflagellate (B). / Source: figure 4 in Pereira et al., Braz. J. Biol. 2017

We are often asked if flow cytometry gives results comparable to traditionally used microscopic analysis. Recently published research validate that results from the CytoBuoy flow cytometers are in good correlation with microscopic assays. The publications are focused on phytoplankton (Haraguchi et al., Pereira et al.) and on filamentous fungi (Ehrgartner et al.).  

Haraguchi et al. show good correlation of micro- and nanophytoplankton counts between traditional microscopy and the CytoSense. The flow cytometer analyzes also picophytoplankton cells (< 5 um), largely overlooked by microscopic assay. The authors demonstrate moreover that carbon biomass can be individually estimated by the CytoSense.

Pereira et al. describe in situ high-frequency monitoring of ciliates and dinoflagellates using submersible flow cytometer CytoSub. Biovolume obtained from the CytoSub measurements is in good agreement with results obtained with classical microscopy. The authors use the CytoSub to demonstrate how abundance and carbon biomass of ciliates and dinoflagellates change in time.

Ehgartner et al. demonstrate that the CytoSense provides morphological characterization of filamentous fungus Penicillium chryzogenum comparable to microscopic assay. The flow cytometer revealed moreover a novel morphological parameter for fungal pellets which is not accessible with the traditional microscopy. Check also previous publications on at-line determination of spore germination (Ehrgartner et al. 2016a) and spore inoculum quality (Ehrgartner et al.2016b). 

Besides giving results comparable with microscopic analyses, the CytoBuoy flow cytometry have the following advantages over this traditional method:

  • faster, automated analysis

Sample composition can be monitored with high frequency, with measurement every few minutes. 

  • measurement of fresh sample on spot

Portability of our flow cytometers means that the sample can be measure directly on the location. This prevents change of sample due to transportation conditions and fixatives. 

  • pictures suitable for taxonomic classification

Using our new camera taxonomists can save time on laborious counting cells and focus on taxonomic classification instead.

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