REAGENTS FOR MICROBIOLOGICAL STUDIES

Modern microbial analysis utilizes not only structural parameters but also functional parameters related to cell physiology. This allows the identification of the physiological stages/forms of microbial cells, significantly enhancing the resolution of obtained results and their diagnostic value, for example, in the food industry. It enables the detection of intermediate forms known as VBNC (viable but non-culturable cells), which due to limited metabolic activity and/or partial damage to their membrane and cell wall, are not detectable by classical microbiology methods (culturing techniques) or techniques based solely on the integrity of the membrane and cell wall. This can lead to false-positive results in microbial contamination assays.

Cyto-Logic recommends the following kits (ThermoFisher Scientific) for assessing combinations of structural and functional parameters in microbial cells:

• BacLight™ RedoxSensor™ Green Vitality Kit – Cat. No. B34954

  This kit includes the DNA-impermeable dye Propidium Iodide (PI) to assess cell viability, and the RedoxSensor Green reagent to measure metabolic activity. This compound serves as a substrate for cellular oxidoreductase enzymes and acts as a precursor to a fluorochrome. The resulting fluorescent dye emits green fluorescence upon excitation, with an intensity directly proportional to the cellular redox potential. This allows for the detection of active, damaged, dormant, and inactive/dead microbial cells.

• LIVE/DEAD™ Cell Vitality Assay Kit, C₁₂ Resazurin/SYTOX™ Green – Cat. No. L34951

  This dual-color fluorescent test distinguishes metabolically active cells from damaged and dead cells. The assay is based on the reduction of C12-resazurin to red-fluorescent C12-resorufin in metabolically active cells, and the uptake of the cell membrane-impermeable, green-fluorescent nucleic acid stain SYTOX Green in cells with damaged plasma membranes (usually in late apoptotic and necrotic cells).

• FungaLight™ Yeast CFDA, AM/Propidium Iodide Vitality Kit – Cat. No. F34953

  This kit contains a membrane integrity indicator (PI) and a cell-permeable substrate for cellular esterases. Once inside the cell, the substrate’s lipophilic blocking and diacetate groups are cleaved by nonspecific esterases, leading to the formation of a fluorescent, charged form that slowly exits the cells.

• BacLight™ RedoxSensor™ CTC Vitality Kit – Cat. No. B34956

  This kit utilizes a fluorescent dye to assess membrane integrity (PI) and the CTC reagent, which is reduced to insoluble formazan by active enzymes of the electron transport chain, producing red fluorescence. Green and blue fluorescent nucleic acid dyes are included as contrast dyes to facilitate cell identification from debris and total cell count.

• LIVE/DEAD™ Yeast Viability Kit – Cat. No. C10427

  This kit combines the innovative dual-color fluorescent probe for assessing yeast viability, FUN® 1, with a fluorescent reagent that labels fungal cell walls, Calcofluor® White M2R. The integrity of the plasma membrane and metabolic activity of yeast cells are required to transform the yellow-green fluorescence of FUN® 1 into red-orange intravacuolar structures within the cell. Calcofluor White M2R stains cell wall chitin with blue fluorescence regardless of the metabolic state.

• CellEvent™ Caspase-3/7 Green Flow Cytometry Assay Kit – Cat. No. C10427

  This kit includes a cell-permeable reagent composed of a four-amino acid peptide (DEVD) linked to a nucleic acid-binding fluorescent dye. During apoptosis, cellular caspases cleave the specific sequence contained within the DEVD peptide, allowing the dye to bind to the cell’s DNA. The kit also contains the fluorescent SYTOX™ AADvanced™ Dead Cell Stain, enabling the differentiation of apoptotic cells from live and necrotic cells.

On top of that we can provide you with conventional kits and fluorescent dyes for assessing the viability of microbial cells based on structural parameters:

• LIVE/DEAD™ BacLight™ Bacterial Viability Kits – Cat. No. L7012

• SYTOX™ AADvanced™ Dead Cell Stain Kit – Cat. No. S10349

• SYTOX AADvanced™ Ready Flow™ Reagent – nr kat. R37173

• SYTOX™ Green Nucleic Acid Stain – 5 mM Solution in DMSO – Cat. No. S7020

• SYTOX™ Blue Dead Cell Stain, for flow cytometry – Cat. No. S34857

• NucGreen™ Dead 488 ReadyProbes™ Reagent (SYTOX™ Green) – Cat. No. R37109

• SYTOX™ Dead Cell Stain Sampler Kit, for flow cytometry – Cat. No. S34862

prof. dr hab. Wojciech Juzwa
aplikacje@cyto-logic.pl
+48 889 735 598