Do polyamines alter the sensitivity of lichens to nitrogen stress?

Pirintsos, Stergios; Munzi, Silvana; Kotzabasis, Kiriakos

doi:10.1016/j.ecoenv.2009.03.001

Cited by 34 publications

(34 citation statements)

References 59 publications

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“…Photosynthesis activity was estimated by the F v /F m parameter (maximum quantum efficiency of PSII) (Pirintsos et al, 2009). When glycerol or glucose was utilized, the maximum quantum yield F v /F m (i.e.…”

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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Section: Photosynthesis Activitymentioning

confidence: 99%

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

et al. 2010

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“…This kind of cellular activity usually requires some time before being effective, especially if bio-synthesis is involved. Pirintsos et al (2009), testing the potential role of three kinds of polyamines on protection from N stress, observed that one was effective already 1 h after the treatment, but that 24 h were necessary to see a recovery in the Fv/Fm ratio of lichens with the other two polyamines. Sanità di Toppi et al (2008) found that phytochelatins were produced in cells of cadmiumexposed lichens 18 h after treatment, and similarly other different stress proteins were produced after 18 and 48 h. In our case, the initial decrease in the Fv/Fm ratio observed in XH could match the time necessary for activation of these potential mechanisms by ammonium excess.…”

Section: Discussionmentioning

confidence: 97%

“…Once again, XH showed less fluctuation in electrolyte concentration than XA, in agreement Planta (2011) 233:333-342 339 with the hypothesis that the latter had greater membrane damage. Chlorophyll fluorescence, assessed through the Fv/Fm ratio, is an effective indicator of the health status of the photosynthetic partner and has been widely used as indicator of lichen vitality (Pirintsos et al 2009;Pisani et al 2009). Fv/Fm ratio values in XA followed a trend similar to that observed in a N-sensitive species, namely E. prunastri (Pirintsos et al 2009), although to a different extent.…”

Section: Discussionmentioning

confidence: 99%

“…Chlorophyll fluorescence, assessed through the Fv/Fm ratio, is an effective indicator of the health status of the photosynthetic partner and has been widely used as indicator of lichen vitality (Pirintsos et al 2009;Pisani et al 2009). Fv/Fm ratio values in XA followed a trend similar to that observed in a N-sensitive species, namely E. prunastri (Pirintsos et al 2009), although to a different extent. After an initial resistance, a threshold of ammonium concentration is reached in XA above which harmful effects cannot be avoided, until total inhibition of photochemical reactions in case of prolonged exposures (Dahlman et al 2003).…”

Section: Discussionmentioning

confidence: 99%

“…Lichen tolerance to reactive N may be related with their capacity to trap N in the outer cellular space and/or specific metabolic characteristics. Pirintsos et al (2009) suggested that polyamines may play a role in the modulation of lichen tolerance to N stress and found that external supply of polyamines increased the resistance of the N-sensitive species Evernia prunastri, while inhibitors of polyamine biosynthesis reduced the tolerance of the N-tolerant species Xanthoria parietina.…”

Section: Introductionmentioning

confidence: 98%

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Do lichens have “memory” of their native nitrogen environment?

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This study aimed to deepen the knowledge about intraspecific mechanisms regulating nitrogen tolerance in lichens to wet nitrogen deposition. Thalli of the nitrophilous lichen Xanthoria parietina were collected from environments with different nitrogen availabilities and immersed in 80 mL of ammonium sulphate (NH₄)₂SO₄ solutions with distinct concentrations (0, 0.025, 0.05 and 0.25 M) for 5 h per day during 3 days in a week. After each soaking event, lichens were air dried. After each treatment, maximal PSII efficiency, localization of ammonium ions, concentrations of K+ and Mg²+ and thalli buffer capacity were determined. Our results show that lichens are marked by their native nitrogen environment, since there were important differences between the physiological responses of X. parietina thalli previously grown in an area with high nitrogen deposition (nitrogen emissions of ca. 13,000 t/year) and those previously grown in an unpolluted area (nitrogen emissions of ca. 500 t/year). Greater N availability seems to enable X. parietina to cope better with the effects of nitrogen pollution.

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Mechanisms of nitrogen deposition effects on temperate forest lichens and trees

et al. 2017

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Abstract. We review the mechanisms of deleterious nitrogen (N) deposition impacts on temperate forests, with a particular focus on trees and lichens. Elevated anthropogenic N deposition to forests has varied effects on individual organisms depending on characteristics both of the N inputs (form, timing, amount) and of the organisms (ecology, physiology) involved. Improved mechanistic knowledge of these effects can aid in developing robust predictions of how organisms respond to either increases or decreases in N deposition. Rising N levels affect forests in micro-and macroscopic ways from physiological responses at the cellular, tissue, and organism levels to influencing individual species and entire communities and ecosystems. A synthesis of these processes forms the basis for the overarching themes of this paper, which focuses on N effects at different levels of biological organization in temperate forests. For lichens, the mechanisms of direct effects of N are relatively well known at cellular, organismal, and community levels, though interactions of N with other stressors merit further research. For trees, effects of N deposition are better understood for N as an acidifying agent than as a nutrient; in both cases, the impacts can reflect direct effects on short time scales and indirect effects mediated through long-term soil and belowground changes. There are many gaps on fundamental N use and cycling in ecosystems, and we highlight the most critical gaps for understanding potential deleterious effects of N deposition. For lichens, these gaps include both how N affects specific metabolic pathways and how N is metabolized. For trees, these gaps include understanding the direct effects of N deposition onto forest canopies, the sensitivity of different tree species and mycorrhizal symbionts to N, the influence of soil properties, and the reversibility of N and acidification effects on plants and soils. Continued study of how these N response mechanisms interact with one another, and with other dimensions of global change, remains essential for predicting ongoing changes in lichen and tree populations across North American temperate forests.

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Do polyamines alter the sensitivity of lichens to nitrogen stress?

Cited by 34 publications

References 59 publications

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

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

Do lichens have “memory” of their native nitrogen environment?

Mechanisms of nitrogen deposition effects on temperate forest lichens and trees

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