Limitations of the Pulse-Modulated Technique for Measuring the Fluorescence Characteristics of Algae

Ting, Claire S.; Owens, Thomas G.

doi:10.1104/pp.100.1.367

Cited by 73 publications

(46 citation statements)

References 18 publications

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“…Phaeodactylum tricornutum was grown in axenic semi-continuous cultures (2 L) in natural seawater containing "f/2" nutrients at 15OC and 100 pmol photons m-'s-' (Ting and Owens, 1992). Cultures were maintained in the early log phase of growth (c0.2 p g Chl 01 mL-') to minimize selfshading.…”

Section: Materials a N D Methodsmentioning

confidence: 99%

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Photochemical and Nonphotochemical Fluorescence Quenching Processes in the Diatom Phaeodactylum tricornutum

1993

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Nonphotochemical fluorescence quenching was found to exist in the dark-adapted state in the diatom Pbaeodactyhm tricornutum. Pretreatment of cells with the uncoupler carbonylcyanide mchlorophenylhydrazone (CCCP) or with nigericin resulted in increases in dark-adapted minimum and maximum fluorescence yields. This suggests that a pH gradient exists across the thylakoid membrane in the dark, which serves to quench fluorescence levels nonphotochemically. The physiological processes involved in establishing this proton gradient were sensitive to anaerobiosis and antimycin A. Based on these results, it is likely that this energization of the thylakoid membrane is due in part to chlororespiration, which involves oxygen-dependent electron flow through the plastoquinone pool. Chlororespiration has been shown previously to occur in diatoms. In addition, we observed that cells treated with 3-(3,4-dichlorophenyI)-l,l-dimethylurea exhibited very strong nonphotochemical quenching when illuminated with actinic light.The rate and extent of this quenching were light-intensity dependent. This quenching was reversed upon addition of CCCP or nigericin and was thus due primarily to the establishment of a pH gradient across the thylakoid membrane. Preincubation of cells with CCCP or nigericin or antimycin A completely abolished this quenching. Cyclic electron transport processes around photosystem I may be involved in establishing this proton gradient across the thylakoid membrane under conditions where linear electron transport is inhibited. At steady state under normal physiological conditions, the qualitative changes in photochemical and nonphotochemical fluorescence quenching at increasing photon flux densities were similar to those in higher plants. However, important quantitative differences existed at limiting and saturating intensities. Dissimilarities in the factors that regulate fluorescence quenching mechanisms in these organisms may account for these differences.One process that competes directly with photochemistry for deactivation of excited-state energy is fluorescence emission from Chl a molecules of the PSII antenna. Changes in the proportion of excited states utilized for photochemistry will result in changes in fluorescence intensity. In recent years, it has been shown that both photochemical and nonphotochemical processes reduce the yield of fluorescence during photosynthesis (Krause et al., 1982). However, our current knowledge of these processes is based primarily on studies with higher plants and green algae. The components involved in qP are present in the PSII reaction center, which has been found to be highly conserved throughout evolution (Thornber, 1986). It is therefore likely that the mechanism of photochemical quenching has also been conserved. In contrast, a diverse group of underlying processes controls qN, whose primary site of action is thought to be in the lightharvesting antennae. With the extensive diversity in the composition of light-harvesting complexes among the algae, it is likely that the m...

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Section: Materials a N D Methodsmentioning

confidence: 99%

“…Fluorescence data acquisition was achieved as previously described (Ting and Owens, 1992). Samples were enclosed in a Hansatech DW2 oxygen electrode chamber (1.5 mL) equipped with an adapter for the PAM fluorometer.…”

Section: Materials a N D Methodsmentioning

confidence: 99%

Photochemical and Nonphotochemical Fluorescence Quenching Processes in the Diatom Phaeodactylum tricornutum

1993

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“…3a). Although chlorophyll fluorescence estimation is not an accurate method for the determination of absolute PSII activity (Schreiber et al, 1995;Ting & Owens, 1992), we have used it in our study as a tool only to confirm active photon capture in the lightharvesting antenna complexes of PSII under both heterotrophic and mixotrophic conditions.…”

Section: Photosynthesis Activitymentioning

confidence: 99%

Mixotrophic and photoheterotrophic metabolism in Cyanothece sp. ATCC 51142 under continuous light

et al. 2010

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The unicellular diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 (Cyanothece 51142) is able to grow aerobically under nitrogen-fixing conditions with alternating light-dark cycles or continuous illumination. This study investigated the effects of carbon and nitrogen sources on Cyanothece 51142 metabolism via 13 C-assisted metabolite analysis and biochemical measurements. Under continuous light (50 mmol photons m "2 s "1 ) and nitrogen-fixing conditions, we found that glycerol addition promoted aerobic biomass growth (by twofold) and nitrogenasedependent hydrogen production [up to 25 mmol H 2 (mg chlorophyll) "1 h "1 ], but strongly reduced phototrophic CO 2 utilization. Under nitrogen-sufficient conditions, Cyanothece 51142 was able to metabolize glycerol photoheterotrophically, and the activity of light-dependent reactions (e.g. oxygen evolution) was not significantly reduced. In contrast, Synechocystis sp. PCC 6803 showed apparent mixotrophic metabolism under similar growth conditions. Isotopomer analysis also detected that Cyanothece 51142 was able to fix CO 2 via anaplerotic pathways, and to take up glucose and pyruvate for mixotrophic biomass synthesis. INTRODUCTIONRising concerns about global warming due to the greenhouse effect have renewed research focused on the biological capture of CO 2 . Cyanobacteria have versatile metabolic capabilities, which allow them to grow under autotrophic, heterotrophic and mixotrophic conditions (Bottomley & Van Baalen, 1978;Eiler, 2006;Yang et al., 2002). More importantly, some cyanobacteria can capture solar energy to fix nitrogen and generate H 2 , thereby serving as a source of biofertilizer and biofuel, while simultaneously consuming atmospheric CO 2 (Bernat et al., 2009;Dutta et al., 2005;Fay, 1992;Madamwar et al., 2000;Tamagnini et al., 2007;Tuli et al., 1996). Cyanothece sp. ATCC 51142 (Cyanothece 51142), a unicellular diazotrophic cyanobacterium, is able to grow aerobically under nitrogen-fixing conditions and has been recognized as contributing to the marine nitrogen cycle. The recent sequencing of the Cyanothece 51142 genome and its transcriptional analysis have uncovered the diurnally oscillatory metabolism of the bacterium in alternating light-dark cycles (photosynthesis during the day and nitrogen fixation at night) (Stöckel et al., 2008;Toepel et al., 2008;Welsh et al., 2008). In general, cyanobacteria use spatial or temporal separation of oxygen-sensitive nitrogen fixation and oxygen-evolving photosynthesis as a strategy for diazotrophic growth (Benemann & Weare, 1974;Fay, 1992). Interestingly, Cyanothece 51142 demonstrates simultaneous N 2 fixation and O 2 evolution under continuous-light conditions, though it appears to be unicellular (Colon-Lopez et al., 1997;Huang & Chow, 1986). For example, a recent study of the transcriptional and translational regulation of continuously illuminated Cyanothece has revealed a strong synthesis capability for nitrogenase and circadian expression of 10 % of its genes (Toepel et al., 2008). Furthermore, Cyanothece str...

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“…As has been pointed out by Ting & Owens (1992) and Buchel & Wilhelm (1993), there have been considerable limitations in the performance of available instrumentation for quenching analysis using dilute samples of unicellular algae with different antenna organization. Some of them were overcome by and Schreiber (1994), because they succeeded to measure fluorescence even in suspensions of very low chlorophyll concentrations (0.1 to 50 1-19 I-').…”

Section: Introductionmentioning

confidence: 99%

“…The PAM system has only been used for a few years in phytoplankton research. There are only a limited number of scientific studies concerned with the estimation of the photochemical efficiency of natural phytoplankton or phytoplankton cultures conducted using the PAM technique (Ting & Owens 1992, Kroon et al 1993, Hofstraat et al 1994. So far this method has not been applied to microphytobenthos communities.…”

Section: Introductionmentioning

confidence: 99%

Photosynthetic activity of natural microphytobenthos populations measured by fluorescence (PAM) and 14C-tracer methods:a comparison

Hartig¹,

Wolfstein²,

Lippemeier³

et al. 1998

Mar. Ecol. Prog. Ser.

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PAM (pulse-amplitude-modulated) fluorescence measurements of motile microphytobenthic algae were carried out in June 1996 at Sylt, Germany. Compansons between "C-based and fluorescence-based production rates were made. A very high correlation between 14C-and fluorescence-based production rates was found for maximal production rates (P, , values). I4C-based maximal production rates var~ed during the study penod between 0.65 and 1.7 mg C mg chl a-' h-', comparable to variations of P,,, measured with the fluorescence-based method. For other photosynthetic parameters [a (maximum light utilization coefficient). Ek (light saturation index), E,,, (light intensity at which P, , , , , is reached)], differences between the 2 methods were much larger. Highest carbon quantum yields ( @, , , ) (m01 C m01 quanta-' absorbed) were obtained at low irradiances. Considering the whole range of investigated carbon quantum yields, we found that initially these values decreased at low to moderate irradiances without a concomitant decline of the actual photochemical efficiency (F,' -F)/F,,' (Fand F,'. m~nimal and maximai iiuoresce~lct' signals in :he !igh!) Therefcre, e high !ine~rit)r between the actual photochemical efficiency and the carbon quantum yield could only be observed up to values of 0.018 m01 C m01 quanta-' This is different to higher plants, for which linearity can be observed up to carbon quantum yields of 0.042 m01 C m01 quanta-' It was shown that, for the calculation of the overall production rates based on the fluorescence method, it is necessary to carefully measure the mean specific absorption coefficient (a') of the algae. Unless this is achieved. PAM measurements cannot be used to calculate absolute production rates.

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Limitations of the Pulse-Modulated Technique for Measuring the Fluorescence Characteristics of Algae

Cited by 73 publications

References 18 publications

Photochemical and Nonphotochemical Fluorescence Quenching Processes in the Diatom Phaeodactylum tricornutum

Photochemical and Nonphotochemical Fluorescence Quenching Processes in the Diatom Phaeodactylum tricornutum

Mixotrophic and photoheterotrophic metabolism in Cyanothece sp. ATCC 51142 under continuous light

Photosynthetic activity of natural microphytobenthos populations measured by fluorescence (PAM) and 14C-tracer methods:a comparison

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