Uplan fl n 100 1.30 oil objective

Cultures were grown in PYE and imaged in exponential phase (OD₆₆₀ of 0.3–0.4) on 1% agarose PYE pads. Microscopy images were acquired using softWoRx 6.0 (GE Healthcare) on a DeltaVision system (GE Healthcare), equipped with a pco.edge sCMOS camera, and an UPlan FL N 100×/1.30 oil objective (Olympus). DivJ-mCherry localization was analyzed using Fiji software package^{30 (link)} with the MicrobeJ plugin^{31 (link)}. Oufti^{32 (link)} was used to quantify cell length and data were analyzed in Prism 7 (GraphPad) with statistical testing using ordinary one-way ANOVA and Tukey’s multiple comparison test. SpmX-mCherry localization and stalk formation (Supplementary Fig. 1) was analysed manually.

Several cells of P. tenue were picked from a natural sample, washed in demineralized water, placed onto a coverslip, and let air-dry. The dry cells were then covered by immersion oil and imaged with a CytoViva Hyperspectral Microscope (CytoViva Inc., AL, USA) in the visible and near-infrared range (400 to 1000 nm) using the Olympus UPlanFL N 100×/1.30 oil objective (Olympus Europa SE & Co. KG, Hamburg, Germany). The microscope was based on an Olympus BX43 stand equipped with a SPECIM spectrograph (Specim, Spectral Imaging Ltd., Oulu, Finland) and the pco.pixelfly USB CCD Camera (PCO AG, Kelheim, Germany). The sample was illuminated with transmitted light of a Fiber-Lite DC-950 halogen illuminator (Dolan-Jenner Industries) coupled into the Olympus BX43 stand. Hyperspectral images were recorded and analyzed with the ENVI software (CytoViva Inc., AL, USA). Per sample type (purple bacteria and green algae), the recorded transmission spectra of four rectangular areas (defined as regions of interest; see fig. S4A) were averaged and used for analysis. First, the averaged transmittance spectra were normalized to the recorded lamp spectrum (also obtained by four averaged measurements) and then converted to relative absorbance spectra for each sample type. The exact sampling areas and absolute absorbance spectra are shown in fig. S4A.

Cultures of strain UJP505 or UJP209 carrying pQFT-mNG were grown overnight in LB-Lennox supplemented with oxytetracycline at 37°C, diluted 1:1,000 in the same medium, and grown for another 3 h at 37°. Amounts of 2 μL of cultures were spotted on LB-Lennox 1% agarose pads containing oxytetracycline with or without 600 μM cumate, and images were acquired every 5 min using a DeltaVision system with softWoRx 6.0 (GE Healthcare) on an Olympus IX71 microscope equipped with a pco.edge scientific complementary metal oxide semiconductor (sCMOS) camera and an UPlan FL N 100×/1.30 oil objective (Olympus) at 37°C. The mNeonGreen signal was recorded using standard green fluorescent protein (GFP) excitation and emission filters with 100-ms exposure time at 50% power. The ImageJ plugin MicrobeJ (58 (link)) was used for quantification of single-cell fluorescence signals on time-lapse data from three biological replicates with two fields of view each.