Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

Abstract

Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures – photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for absorption, is unknown. Studying Chlorobaculum tepidum cultures with far-red to near-infrared light-emitting diodes, we found that these bacteria react to changes in energy flow by regulating the amount of light-absorbing pigments and the size of the chlorosomes. Surprisingly, our results indicate that the bacteria can survive in near-infrared lights capturing low-frequency photons by the intermediate units of the light-harvesting complex. The latter strategy may be used by the species recently found near hydrothermal vents in the Pacific Ocean.

Aerobic Anoxygenic Phototrophic Bacteria Promote the Development of Biological Soil Crusts

“…Near-infrared has been demonstrated to be able to stimulate the growth of a purple bacterial strain of Rhodopseudomonas sp., which led to an improved efficiency of wastewater treatment process ( Qi et al, 2017 ). Certain anaerobic green sulfur photosynthetic bacteria could even grow under monochromatic NIR light at a very low photo flux (<10 μmol.m −2 .s −1 , Saikin et al, 2014 ). In this study, we employed a NIR light intensity of 70 lux (about 7 μmol.m −2 .s −1 ), which led to a 9 days earlier development of BSCs in the Red + NIR treatment than that in the Red alone.…”

Unanticipated Geochemical and Microbial Community Structure under Seasonal Ice Cover in a Dilute, Dimictic Arctic Lake

“…However, both PSB and GSB carry out anoxygenic photosynthesis using reduced sulfur and are likely inhibited by elevated DO present above the oxycline, and are adapted to low light conditions ( Vila and Abella, 2001 ). GSB have been reported to grow under near-infrared light at photon fluxes <10 μmol m -2 s -1 ( Saikin et al, 2014 ).…”

A Nanophotonic Structure Containing Living Photosynthetic Bacteria

“…Scale bar is 1 µm. Note that the size and shape of the bacteria is dependent upon the light conditions during growth . b) Normalized extinction spectra of 0.4% trypan blue (TB) aqueous solution (blue line) and Cba.…”

“…We have previously suggested that the polariton branches may provide an alternative pathway for excitons to migrate through the photosynthetic system, bypassing various states . The baseplate exciton wavelength is at 790 nm, while the FMO and reaction center are positioned at 810 and 840 nm, respectively.…”