Conidia-based fluorescence quantification of Streptomyces

Area of Science:

• Microbiology
• Molecular Biology

Background:

• Accurate enumeration of filamentous bacteria, such as Streptomyces, is challenging due to their complex morphology and clumping in cultures.
• Existing methods may not fully capture the true cell numbers in these challenging bacterial structures.

Purpose of the Study:

• To develop a novel and reliable method for determining cell numbers in filamentous bacteria.
• To establish a conidia-based fluorescence assay for Streptomyces cell enumeration.

Main Methods:

• A conidia-based approach was developed, utilizing SYBR Green 1 DNA-binding stain.
• Fluorescence of stained conidia was correlated with the DNA content in Streptomyces.
• The conidia assay results were compared with those obtained from a quantitative polymerase chain reaction (qPCR) assay.

Main Results:

• The conidia-based assay recovered 34 to 62% of cells compared to the qPCR assay.
• The discrepancy is likely due to incomplete DNA extraction from Gram-positive bacteria, not underestimation by the conidia assay.
• The conidia-based method proved to be a rapid and dependable technique.

Conclusions:

• The developed conidia-based fluorescence assay is a fast and reliable method for counting cells in Streptomyces filaments.
• This approach has potential applicability to other filamentous bacteria, provided appropriate standard curves are established.