Possible Roles of Near-infrared Light on the Photosynthesis in &lt;i&gt;Synechocystis&lt;/i&gt; sp. PCC6803 under Solar Simulating Artificial Light

Oshita, Kota; Suzuki, Toshiharu; Kawano, Tomonori

doi:10.2525/ecb.56.17

Cited by 3 publications

(2 citation statements)

References 15 publications

(18 reference statements)

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“…We have previously confirmed that photosynthetic activities in PCC6803 cells under simulated solar light and artificial white light were shown to obey the Platt-Jasby model [32,33]. As discussed earlier [34,35], higher generality can be conferred to the mathematical model by converting the Michaelis-Menten-type equation (11) into a Hill-type equation (12).…”

Section: Photosynthetic Kinetics Behind the Upper Growth Limitsupporting

confidence: 70%

Hidden Allee effect in photosynthetic organisms

Ohkawa

Takatsuka

Kawano

2020

Communicative & Integrative Biology

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In ecology and population biology, logistic equation is widely applied for simulating the population of organisms. By combining the logistic model with the low-density effect called Allee effect, several variations of mathematical expressions have been proposed. The upper half of the work was dedicated to establish a novel equation for highly flexible density effect model with Allee threshold. Allee effect has been rarely observed in microorganisms with asexual reproduction despite of theoretical studies. According to the exploitation ecosystem hypotheses, plants are believed to be insensitive to Allee effect. Taken together, knowledge on the existence of lowdensity effect in photosynthetic microorganisms is required for redefining the ecological theories emphasizing the photosynthetic organisms as the basis for food chains. Therefore, in the lower half of the present article, we report on the possible Allee effect in photo-autotrophic organisms, namely, green paramecia, and cyanobacteria. Optically monitored growth of green paramecia was shown to be regulated by Allee-like weak low-density effect under photo-autotrophic and photoheterotrophic conditions. Insensitiveness of wild type cyanobacteria (Synechocystis sp. Strain PCC6803) to low-density effect was confirmed, as consistent with our empirical knowledge. In contrast, a mutant line of PCC6803 impaired with a photosynthesis-related pxcA gene was shown to be sensitive to typical Allee's low-density effect (i.e. this line of cells failed to propagate at low cellular density while cells start logarithmic growth at relatively higher inoculating density). This is the first observation that single-gene mutation in an autotrophic organism alters the sensitivity to Allee effect.

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Section: Photosynthetic Kinetics Behind the Upper Growth Limitsupporting

confidence: 70%

Hidden Allee effect in photosynthetic organisms

Ohkawa

Takatsuka

Kawano

2020

Communicative & Integrative Biology

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“…However, previous studies have revealed that most of bathyarchaeotal members prefer subsurface of the sediments and large numbers of Bathyarchaeota were found in deeper biosphere where visible light could barely reach [6,18,22,30], thus Bathyarchaeota may not capture visible light with rhodopsin. Infrared light has been proved to be an available energy source for some plants and bacteria [31][32][33][34][35], and rhodopsin could gain longerwavelength or even infrared sensitivity by substituting all-trans-retinal (chromophore for archaeal cells) with 3, 4-dehydroretinal [36], retinal A2, 3-methylamino-16nor-1,2,3,4-didehydroretinal, or other analogs [37].…”

Section: Light Sensingmentioning

confidence: 99%

Genomic and transcriptomic evidence of light-sensing, porphyrin biosynthesis, Calvin-Benson-Bassham cycle, and urea production in Bathyarchaeota

et al. 2020

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Background: Bathyarchaeota, a newly proposed archaeal phylum, is considered as an important driver of the global carbon cycle. However, due to the great diversity of them, there is limited genomic information that accurately encompasses the metabolic potential of the entire archaeal phylum. Results: In the current study, nine metagenome-assembled genomes of Bathyarchaeota from four subgroups were constructed from mangrove sediments, and metatranscriptomes were obtained for evaluating their in situ transcriptional activities. Comparative analyses with reference genomes and the transcripts of functional genes posit an expanded role for Bathyarchaeota in phototrophy, autotrophy, and nitrogen and sulfur cycles, respectively. Notably, the presence of genes for rhodopsins, cobalamin biosynthesis, and the oxygen-dependent metabolic pathways in some Bathyarchaeota subgroup 6 genomes suggest a light-sensing and microoxic lifestyle within this subgroup. Conclusions: The results of this study expand our knowledge of metabolic abilities and diverse lifestyles of Bathyarchaeota, highlighting the crucial role of Bathyarchaeota in geochemical cycle.

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