Li 190 quantum sensor

Chlorella vulgaris ESP-31 was obtained from Prof. Jo-Shu Chang, Department of Chemical Engineering, National Cheng-Kung University, Tainan, Taiwan [34 (link)]. Chlorella vulgaris ESP-31 cells were cultured in 50 mL BG-11 medium, pH 7.4 [45 ]. The cultures were normally incubated at 28 °C under continuous light conditions (approximately 50 μmol m⁻² s⁻¹, illuminated by a TL5 lamp (Philips, Singapore). The light intensity was measured by a Li-250A Light Meter with a Li-190 quantum sensor (Li-COR Inc., Lincoln, Nebraska, USA).

B. napus and Arabidopsis seeds were sown individually on compost and stratified at 4 °C in the dark for 4 days before transferring to controlled environment cabinets, where they were germinated and grown under 70 µmol m⁻² s⁻¹ white light (warm white fluorescent L36W/30 tubes; Osram, Munich, Germany) at 20 °C. Plants were grown under continuous white light to minimise the influence of circadian rhythm on transcriptional regulation. White light fluence rates were measured using a LI-250A light meter attached to a LI-190 quantum sensor (LI-COR, Lincoln, NE, USA).

For microsensor measurements, CCA specimens of approximately 10 cm² were placed into a plexiglass flow cell (19 cm x 9 cm x 9.5 cm) attached to a reservoir. Water was pumped longitudinally through the chamber at a rate of approximately 2 cm s^-1 (judged by particle movement) and passed through a perforated wall (diffusor) at the entrance and exit of the flow-chamber in order to create laminar flow at the thalli surface. The outflow water was recycled via a 1.5 L aerated reservoir. The outflow rate was maintained at approximately 0.004 L s^-1, resulting in a four-minute residence time in the flow chamber. The total volume of the flow chamber and the reservoir was 2.5 L. Seawater temperature in the flow chamber was maintained at 27°C with a Julabo warming thermostat (Julabo, Seelbach, Germany). The light source used during incubations was a fiber optic halogen lamp (Schott KL1500, Schott, Mainz, Germany) and the down-welling photosynthetically active radiation (PAR) at each light level (1–5) was measured using a LI-190 Quantum Sensor attached to an LI-COR light meter (LI-COR Biosciences, Lincoln, Nebraska, USA). The PAR intensities used during the incubation experiments consisted of five levels between 0–1400 (0, 20, 100, 280, 800, 1400) μmol photons m^-2 s^-1.

All plants were exposed to a to a PPFD of 529 ± 6 μmol m^-2 s^-1 starting when the plants were placed in the growth chamber until the FBV stage. At FBV stage the plants were randomly assigned to one of the two following light treatments. The first treatment, hereafter referred to as “high PPFD,” corresponded to exposure to a continuous PPFD of 529 ± 6 μmol m^-2 s^-1 until 14 days after the FBV stage. In the second treatment, hereafter referred to as “low PPFD,” the plants were exposed to 89 ± 1 μmol m^-2 s^-1 from the FBV stage to 14 days after the FBV stage. PPFD was measured with a horizontal cosine corrector quantum sensor (LI-190 Quantum Sensor, LI-COR, Lincoln, NE, United States).

Twelve hours post-transfection, an in-house blue LED device (465 nm, strip of LEDs glued to PCB board; Amazon) was placed 8 cm or 16 cm above the plate. Note, the constraints of the light source also had to be altered (twice the distance than our cell lines; 16 cm) due to higher sensitivity of iPSNs to the blue-light and the heat it produces, compared to N2a cell lines. The intensity of the light received by cells was measured to be to 8 W/m²; as previously reported by [46 (link)]. Verified, using the LI-190 Quantum Sensor and LI-250A light meter (LI-COR Biosciences). The LED strips were connected to SLBSTORES 3528 5050 12V DC Mini Remote Controller (Amazon) for variations of on/off patterns to best match a cycle of 20 s ‘on’ and 60 s ‘off’ as recommended per Motta-Mena et al [43 (link)]. The control plate was kept in a PCB blackout box with breathable air slots, (a shelf in the incubator, above and away from the light source shelf). For transiently transfected cells, 24 h post-transfection, samples were collected/fixed for analysis.

Anaerobic cultures of Rba. sphaeroides grown under photosynthetic conditions were exposed to 15 or 20 W MEGAMAN^® CFL bulbs to achieve the desired light intensity. Light intensity was measured in μmol photons s⁻¹ m² using a LI‐250A light meter equipped with a LI‐190 Quantum sensor (LI‐COR Biosciences, USA). One millilitre of oxygen‐limited culture was used to inoculate a full 30 ml universal of M22+ medium. A small magnetic stir bar was placed in the bottom of the bottle, and the culture was incubated at the desired light intensity, overnight with gentle agitation. This culture was used to inoculate either a 500 ml medical flat or a 1.2 l Roux culture bottle filled with M22+ medium and capped with a rubber bung. These cultures also contained a magnetic stir bar to provide gentle agitation.