Evidence for the Non-involvement of Nitric Oxide Synthase in Nitric Oxide Production by the Green Alga Scenedesmus obliquus

Mallick, Nirupama; Mohn, Friedrich Helmuth; Rai, L.C.; Soeder, Carl J.

doi:10.1016/s0176-1617(00)80084-x

Cited by 30 publications

(22 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 and 2) is that NO acts as an antioxidant in this system. Our results with barley aleurone layers are in line with data showing, for example, that NO can delay senescence (Mallick et al, 2000), prevent ROSinduced cytotoxicity (Beligni and Lamattina, 1999), and slow chlorophyll loss resulting from pathogen infection (Laxalt et al, 1997).…”

Section: Discussionsupporting

confidence: 91%

“…Other sources of NO are likely, though controversy exists regarding the synthesis of NO in plants by NO synthase (NOS). Genes encoding NOS have not been identified in the sequenced genomes of plants (Yamasaki, 2000) or their ancestors (Mallick et al, 2000), and NOS genes appear absent from the genomes of bacteria and fungi. Yet NOS activity has been reported in plants (Ninnemann and Maier, 1996;Delledonne et al, 1998;Durner et al, 1998;Leshem et al, 1998), and inhibitors of NOS have been shown to reduce this activity (Ninnemann and Maier, 1996;Delledonne et al, 1998).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Nitric Oxide Acts as an Antioxidant and Delays Programmed Cell Death in Barley Aleurone Layers

et al. 2002

View full text Add to dashboard Cite

Nitric oxide (NO) is a freely diffusible, gaseous free radical and an important signaling molecule in animals. In plants, NO influences aspects of growth and development, and can affect plant responses to stress. In some cases, the effects of NO are the result of its interaction with reactive oxygen species (ROS). These interactions can be cytotoxic or protective. Because gibberellin (GA)-induced programmed cell death (PCD) in barley (Hordeum vulgare cv Himalaya) aleurone layers is mediated by ROS, we examined the effects of NO donors on PCD and ROS-metabolizing enzymes in this system. NO donors delay PCD in layers treated with GA, but do not inhibit metabolism in general, or the GA-induced synthesis and secretion of-amylase.-Amylase secretion is stimulated slightly by NO donors. The effects of NO donors are specific for NO, because they can be blocked completely by the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. The antioxidant butylated hydroxy toluene also slowed PCD, and these data support our hypothesis that NO is a protective antioxidant in aleurone cells. The amounts of CAT and SOD, two enzymes that metabolize ROS, are greatly reduced in aleurone layers treated with GA. Treatment with GA in the presence of NO donors delays the loss of CAT and SOD. We speculate that NO may be an endogenous modulator of PCD in barley aleurone cells.

show abstract

Section: Discussionsupporting

confidence: 91%

mentioning

confidence: 99%

Nitric Oxide Acts as an Antioxidant and Delays Programmed Cell Death in Barley Aleurone Layers

et al. 2002

View full text Add to dashboard Cite

show abstract

“…Emission of NO has been reported in green algae [22–24], cyanobacteria [22] and a variety of higher plants [25,26]. However, the source of NO in plant cells is still controversial [27].…”

Section: Discussionmentioning

confidence: 99%

Reversible inhibition of photophosphorylation in chloroplasts by nitric oxide

Takahashi¹,

Yamasaki²

2002

FEBS Letters

116

View full text Add to dashboard Cite

Nitric oxide (NO) is a bioactive molecule involved in diverse physiological functions in plants. Here we demonstrate that NO is capable of regulating the activity of photophosphorylation in chloroplasts. The electron transport activity in photosystem II determined from chlorophyll a fluorescence was inhibited by NO. NO also inhibited light-induced v vpH formation across the thylakoid membrane. High concentrations of nitrite and nitrate did not show such inhibitory effects, suggesting that the inhibition is not due to uncoupling effects of the oxidized products of NO. ATP synthesis activity upon illumination was severely inhibited by NO (IC 50 = 0.7 W WM). The inhibition was found to be temporary and the activity was completely recovered by removing NO. Bovine hemoglobin and bicarbonate were effective in preventing NO-dependent inhibition of photophosphorylation. These results indicate that NO is a reversible inhibitor of photosynthetic ATP synthesis. ß

show abstract

“…To date, a NOS homolog has been found in the green alga Ostreococcus (Foresi et al, 2010) but not in other algae nor in land plants. Furthermore L-Arg plays little role in NO production under nitrogen replete conditions, whether in C. reinhardtii (Sakihama et al, 2002) or in the closely related alga Scenedesmus obliquus (Mallick et al, 2000b). Nevertheless, the NO-dependent repression of the nitrate assimilation pathway by ammonium is partially prevented upon addition of the L-Arg analog L-NAME, a known NOS inhibitor, suggesting some NOS-like activity in C. reinhardtii (de Montaigu et al, 2010).…”

Section: Intracellular Nitrite Is the Most Likely Source Of No Producmentioning

confidence: 98%

Nitric Oxide–Triggered Remodeling of Chloroplast Bioenergetics and Thylakoid Proteins upon Nitrogen Starvation inChlamydomonas reinhardtii

et al. 2014

View full text Add to dashboard Cite

Starving microalgae for nitrogen sources is commonly used as a biotechnological tool to boost storage of reduced carbon into starch granules or lipid droplets, but the accompanying changes in bioenergetics have been little studied so far. Here, we report that the selective depletion of Rubisco and cytochrome b 6 f complex that occurs when Chlamydomonas reinhardtii is starved for nitrogen in the presence of acetate and under normoxic conditions is accompanied by a marked increase in chlororespiratory enzymes, which converts the photosynthetic thylakoid membrane into an intracellular matrix for oxidative catabolism of reductants. Cytochrome b 6 f subunits and most proteins specifically involved in their biogenesis are selectively degraded, mainly by the FtsH and Clp chloroplast proteases. This regulated degradation pathway does not require light, active photosynthesis, or state transitions but is prevented when respiration is impaired or under phototrophic conditions. We provide genetic and pharmacological evidence that NO production from intracellular nitrite governs this degradation pathway: Addition of a NO scavenger and of two distinct NO producers decrease and increase, respectively, the rate of cytochrome b 6 f degradation; NO-sensitive fluorescence probes, visualized by confocal microscopy, demonstrate that nitrogen-starved cells produce NO only when the cytochrome b 6 f degradation pathway is activated.

show abstract

Evidence for the Non-involvement of Nitric Oxide Synthase in Nitric Oxide Production by the Green Alga Scenedesmus obliquus

Cited by 30 publications

References 12 publications

Nitric Oxide Acts as an Antioxidant and Delays Programmed Cell Death in Barley Aleurone Layers

Nitric Oxide Acts as an Antioxidant and Delays Programmed Cell Death in Barley Aleurone Layers

Reversible inhibition of photophosphorylation in chloroplasts by nitric oxide

Nitric Oxide–Triggered Remodeling of Chloroplast Bioenergetics and Thylakoid Proteins upon Nitrogen Starvation inChlamydomonas reinhardtii

Contact Info

Product

Resources

About