Sybr green 1 sbi

Small fragments of gypsum showing distinct signs of endolithic colonization with a green/orange layer beneath the rock surface and a green layer just above the bottom of the gypsum sample were scraped and suspended in double-distilled water. Suspensions were vortexed (2 min) and allowed to settle for 1 min before removing the supernatant, which was centrifuged for 10 min at 5000 g. The pellet was then stained with SYBR Green I (SBI) (Molecular Probes), a fluorocromes used for the specific staining of nucleic acids. Bright field images, SBI fluorescence and photosynthetic pigment autofluorescence were visualized in a Zeiss AxioImager D1 fluorescence microscope (Carl Zeiss, Jena, Germany). Detailed procedures are provided in Supplementary Section S4.

Small pieces of gypsum, colonized by pigmented endoliths were scraped and suspended in double-distilled water. The suspension was stained with SYBR Green I (SBI) (Molecular Probes), which is a fluorochrome specifically used for the staining of nucleic acids. Observations were made first in differential interference contrast (DIC) using a Zeiss AXIO Imager M2 fluorescence microscope (Carl Zeiss, Jena, Germany) plus an Apochrome x60, n = 1.4 Zeiss oil-immersion objective. A CCD Axiocam HRc Rev. 2 camera and AXIOVISION 4.7 software (Carl Zeiss, Oberkochen, Germany) were used to capture and record the DIC images. Images were acquired using a Multichannel Image Acquisition system, employing an eGFP filter set (Zeiss Filter Set 38; Ex/Em: 450–490/500–550 nm), a DAPI filter set (Zeiss Filter Set 49; Ex/Em: 365/420–470 nm), and a Rhodamine filter set (Zeiss Filter Set 20; Ex/Em: 540–552/567–647 nm).