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Optimization and effects of different culture conditions on growth of Halomicronema hongdechloris - a filamentous cyanobacterium containing chlorophyll f.

Li Y, Lin Y, Loughlin PC, Chen M - Front Plant Sci (2014)

Bottom Line: High performance liquid chromatography on H. hongdechloris pigments confirmed that chlorophyll a is the major chlorophyll and chlorophyll f constitutes ~10% of the total chlorophyll from cells grown under far-red light.The total photosynthetic oxygen evolution yield per cell showed no changes under different light conditions, which confirms the involvement of chlorophyll f in oxygenic photosynthesis.The implications of the presence of chlorophyll f in H. hongdechloris and its relationship with the ambient light environment are discussed.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney Sydney, NSW, Australia.

ABSTRACT
A chlorophyll f containing cyanobacterium, Halomicronema hongdechloris (H. hongdechloris) was isolated from a stromatolite cyanobacterial community. The extremely slow growth rate of H. hongdechloris has hindered research on this newly isolated cyanobacterium and the investigation of chlorophyll f-photosynthesis. Therefore, optimizing H. hongdechloris culture conditions has become an essential requirement for future research. This work investigated the effects of various culture conditions, essential nutrients and light environments to determine the optimal growth conditions for H. hongdechloris and the biosynthetic rate of chlorophyll f. Based on the total chlorophyll concentration, an optimal growth rate of 0.22 ± 0.02 day(-1)(doubling time: 3.1 ± 0.3 days) was observed when cells were grown under continuous illumination with far-red light with an intensity of 20 μE at 32°C in modified K + ES seawater (pH 8.0) with additional nitrogen and phosphor supplements. High performance liquid chromatography on H. hongdechloris pigments confirmed that chlorophyll a is the major chlorophyll and chlorophyll f constitutes ~10% of the total chlorophyll from cells grown under far-red light. Fluorescence confocal image analysis demonstrated changes of photosynthetic membranes and the distribution of photopigments in response to different light conditions. The total photosynthetic oxygen evolution yield per cell showed no changes under different light conditions, which confirms the involvement of chlorophyll f in oxygenic photosynthesis. The implications of the presence of chlorophyll f in H. hongdechloris and its relationship with the ambient light environment are discussed.

No MeSH data available.


Related in: MedlinePlus

Effects of light conditions on the growth profile of H. hongdechloris.(A) Growth profile of H. hongdechloris under different light conditions. Optimal intensities for all red/orange LED lights were 20 μE, but 40 μE for white light. The solid gray line and equation denotes the trend line of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase under the FR/20 μE condition. A insert: Comparison of the trend lines of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase for cells grown under different light conditions. FR, far-red; OR, orange-red; RL, red light and WL, white light. Error bars represent SDs (n = 8). Effects of (B) FR and (C) WL light intensities on the growth rate of H. hongdechloris. Error bars represent SE (n = 8).
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Figure 3: Effects of light conditions on the growth profile of H. hongdechloris.(A) Growth profile of H. hongdechloris under different light conditions. Optimal intensities for all red/orange LED lights were 20 μE, but 40 μE for white light. The solid gray line and equation denotes the trend line of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase under the FR/20 μE condition. A insert: Comparison of the trend lines of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase for cells grown under different light conditions. FR, far-red; OR, orange-red; RL, red light and WL, white light. Error bars represent SDs (n = 8). Effects of (B) FR and (C) WL light intensities on the growth rate of H. hongdechloris. Error bars represent SE (n = 8).

Mentions: H. hongdechloris pigment composition has previously been reported to change in response to two light conditions: WL light/20 μE and 720 nm LED light/10–15 μE (Chen et al., 2012). H. hongdechloris cells grow under the all tested orange to red LED lights and also WL light (Figure 3A). However, no growth was observed when cells were grown under green or blue light at intensities of either 10 or 20 μE (data not shown). The growth rates under the white and red light conditions examined vary considerably with an increased growth rate observed in the following order: FR/20 μE ≥ WL/40 μE > OR/20 μE > RL/20 μE based on total chlorophyll content.


Optimization and effects of different culture conditions on growth of Halomicronema hongdechloris - a filamentous cyanobacterium containing chlorophyll f.

Li Y, Lin Y, Loughlin PC, Chen M - Front Plant Sci (2014)

Effects of light conditions on the growth profile of H. hongdechloris.(A) Growth profile of H. hongdechloris under different light conditions. Optimal intensities for all red/orange LED lights were 20 μE, but 40 μE for white light. The solid gray line and equation denotes the trend line of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase under the FR/20 μE condition. A insert: Comparison of the trend lines of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase for cells grown under different light conditions. FR, far-red; OR, orange-red; RL, red light and WL, white light. Error bars represent SDs (n = 8). Effects of (B) FR and (C) WL light intensities on the growth rate of H. hongdechloris. Error bars represent SE (n = 8).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3934312&req=5

Figure 3: Effects of light conditions on the growth profile of H. hongdechloris.(A) Growth profile of H. hongdechloris under different light conditions. Optimal intensities for all red/orange LED lights were 20 μE, but 40 μE for white light. The solid gray line and equation denotes the trend line of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase under the FR/20 μE condition. A insert: Comparison of the trend lines of linear regressions of the logarithm of total chlorophyll concentration in the exponential phase for cells grown under different light conditions. FR, far-red; OR, orange-red; RL, red light and WL, white light. Error bars represent SDs (n = 8). Effects of (B) FR and (C) WL light intensities on the growth rate of H. hongdechloris. Error bars represent SE (n = 8).
Mentions: H. hongdechloris pigment composition has previously been reported to change in response to two light conditions: WL light/20 μE and 720 nm LED light/10–15 μE (Chen et al., 2012). H. hongdechloris cells grow under the all tested orange to red LED lights and also WL light (Figure 3A). However, no growth was observed when cells were grown under green or blue light at intensities of either 10 or 20 μE (data not shown). The growth rates under the white and red light conditions examined vary considerably with an increased growth rate observed in the following order: FR/20 μE ≥ WL/40 μE > OR/20 μE > RL/20 μE based on total chlorophyll content.

Bottom Line: High performance liquid chromatography on H. hongdechloris pigments confirmed that chlorophyll a is the major chlorophyll and chlorophyll f constitutes ~10% of the total chlorophyll from cells grown under far-red light.The total photosynthetic oxygen evolution yield per cell showed no changes under different light conditions, which confirms the involvement of chlorophyll f in oxygenic photosynthesis.The implications of the presence of chlorophyll f in H. hongdechloris and its relationship with the ambient light environment are discussed.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney Sydney, NSW, Australia.

ABSTRACT
A chlorophyll f containing cyanobacterium, Halomicronema hongdechloris (H. hongdechloris) was isolated from a stromatolite cyanobacterial community. The extremely slow growth rate of H. hongdechloris has hindered research on this newly isolated cyanobacterium and the investigation of chlorophyll f-photosynthesis. Therefore, optimizing H. hongdechloris culture conditions has become an essential requirement for future research. This work investigated the effects of various culture conditions, essential nutrients and light environments to determine the optimal growth conditions for H. hongdechloris and the biosynthetic rate of chlorophyll f. Based on the total chlorophyll concentration, an optimal growth rate of 0.22 ± 0.02 day(-1)(doubling time: 3.1 ± 0.3 days) was observed when cells were grown under continuous illumination with far-red light with an intensity of 20 μE at 32°C in modified K + ES seawater (pH 8.0) with additional nitrogen and phosphor supplements. High performance liquid chromatography on H. hongdechloris pigments confirmed that chlorophyll a is the major chlorophyll and chlorophyll f constitutes ~10% of the total chlorophyll from cells grown under far-red light. Fluorescence confocal image analysis demonstrated changes of photosynthetic membranes and the distribution of photopigments in response to different light conditions. The total photosynthetic oxygen evolution yield per cell showed no changes under different light conditions, which confirms the involvement of chlorophyll f in oxygenic photosynthesis. The implications of the presence of chlorophyll f in H. hongdechloris and its relationship with the ambient light environment are discussed.

No MeSH data available.


Related in: MedlinePlus