Methylesters ofl-Arginine andN-Nitro-l-arginine Induce Nitric Oxide Synthase inStaphylococcus aureus

Choi, Wahn Soo; Seo, Dong Wan; Chang, Man; Han, Jeung Whan; Hong, Sung Youl; Paik, Woon Ki; Lee, Hyang Woo

doi:10.1006/bbrc.1998.8638

Cited by 17 publications

(12 citation statements)

References 18 publications

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“…The apparent contradiction between the results obtained with NOS inhibitors and NOS substrate was already stated as the L-arginine paradox and could be explained by the presence of endogenous NOS inhibitors (Tsikas et al 2000). Similar results were also described in two other reports in which known inhibitors of mammalian NOS were unable to inhibit NOS activity (Choi et al 1998;Cohen and Yamasaki 2003). However, other NO sources in Azospirillum growing under different conditions, as well as complementary pathways cannot be discarded.…”

Section: Discussionsupporting

confidence: 65%

Nitric Oxide is Involved in the Azospirillum brasilense-induced Lateral Root Formation in Tomato

Creus

Graziano

Casanovas

et al. 2005

Planta

232

121

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Azospirillum spp. is a well known plant-growth-promoting rhizobacterium. Azospirillum-inoculated plants have shown to display enhanced lateral root and root hair development. These promoting effects have been attributed mainly to the production of hormone-like substances. Nitric oxide (NO) has recently been described to act as a signal molecule in the hormonal cascade leading to root formation. However, data on the possible role of NO in free-living diazotrophs associated to plant roots, is unavailable. In this work, NO production by Azospirillum brasilense Sp245 was detected by electron paramagnetic resonance (6.4 nmol. g-1 of bacteria) and confirmed by the NO-specific fluorescent probe 4,5-diaminofluorescein diacetate (DAF-2 DA). The observed green fluorescence was significantly diminished by the addition of the specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). Azospirillum-inoculated and noninoculated tomato (Lycopersicon esculentum L.) roots were incubated with DAF-2 DA and examined by epifluorescence microscopy. Azospirillum-inoculated roots displayed higher fluorescence intensity which was located mainly at the vascular tissues and subepidermal cells of roots. The Azospirillum-mediated induction of lateral root formation (LRF) appears to be NO-dependent since it was completely blocked by treatment with cPTIO, whereas the addition of the NO donor sodium nitroprusside partially reverted the inhibitory effect of cPTIO. Overall, the results strongly support the participation of NO in the Azospirillum-promoted LRF in tomato seedlings.

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Section: Discussionsupporting

confidence: 65%

Nitric Oxide is Involved in the Azospirillum brasilense-induced Lateral Root Formation in Tomato

Creus

Graziano

Casanovas

et al. 2005

Planta

232

121

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“…A predator ingesting even a small amount of the anuran skin secretion could be seriously affected if even part of its nitric oxide messenger capability is reduced. The predator could either be large, or small (bacteria have recently been shown to contain NOS [72–75]).…”

Section: Discussionmentioning

confidence: 99%

Amphibian peptides that inhibit neuronal nitric oxide synthase

Doyle

Llewellyn

Brinkworth

et al. 2002

European Journal of Biochemistry

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Two neuropeptides have been isolated and identi®ed from the secretions of the skin glands of the Stony Creek Frog Litoria lesueuri. The ®rst of these, the known neuropeptide caerulein 1.1, is a common constituent of anuran skin secretions, and has the sequence pEQY(SO 3 )TGWMDF-NH 2 . This neuropeptide is smooth muscle active, an analgaesic more potent than morphine and is also thought to be a hormone. The second neuropeptide, a new peptide, has been named lesueurin and has the primary structure GLLDILKKVGKVA-NH 2 . Lesueurin shows no signi®-cant antibiotic or anticancer activity, but inhibits the formation of the ubiquitious chemical messenger nitric oxide from neuronal nitric oxide synthase (nNOS) at IC 50 (16.2 lM), and is the ®rst amphibian peptide reported to show inhibition of nNOS. As a consequence of this activity, we have tested other peptides previously isolated from Australian amphibians for nNOS inhibition. There are three groups of peptides that inhibit nNOS (IC 50 at lM concentrations): these are (a) the citropin/aurein type peptides (of which lesueurin is a member), e.g. citropin 1.1 (GLFDVIKKVASVIGGL-NH 2 ) (8.2 lM); (b) the frenatin type peptides, e.g. frenatin 3 (GLMSVLGHAVGNVLG GLFKPK-OH) (6.8 lM); and (c) the caerin 1 peptides, e.g. caerin 1.8 (GLFGVLGSIAKHLLPHVVPVIAEKL-NH 2 ) (1.7 lM). From Lineweaver±Burk plots, the mechanism of inhibition is revealed as noncompetitive with respect to the nNOS substrate arginine. When the nNOS inhibition tests with the three peptides outlined above were carried out in the presence of increasing concentrations of Ca 2+ calmodulin, the inhibition dropped by 50% in each case. In addition, these peptides also inhibit the activity of calcineurin, another enzyme that requires the presence of the regulatory protein Ca 2+ calmodulin. It is proposed that the amphibian peptides inhibit nNOS by interacting with Ca 2+ calmodulin, and as a consequence, blocks the attachment of this protein to the calmodulin domain of nNOS.Keywords: amphibians; Litoria lesueuri; neuropeptides; nNOS inhibition; Ca 2+ calmodulin interaction.Amphibians have rich chemical arsenals that form an integral part of their defence system, and also assist with the regulation of dermal physiological action. In response to a variety of stimuli, host defence compounds are secreted from specialized glands onto the dorsal surface and into the gut of the amphibian [1±4]. A number of different types of bio-active peptides have been identi®ed from the glandular skin secretions of Australian anurans of the Litoria genus, including (a) neuropeptides of the caerulein family [5±8], and (b) wide-spectrum antibiotics, e.g. the caerin peptides from green tree frogs of the genus Litoria [6±8], the citropins from the tree frog Litoria citropa [9,10], and the aureins from the bell frogs Litoria aurea and Litoria raniformis [11]. Amongst the most active of these are neuropeptide caerulein 1.1, and the antibiotics caerin 1.1, citropin 1.1 and aurein 1.2: caerulein 1.1 pEQGY(SO 3 )TGWMDF-NH 2 ; caerin 1.1 GLLSVLGSVAKHVL...

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“…A predator ingesting even a small amount of the nNOS inhibitor could be seriously affected if only part of its NO messenger capability is reduced. All animals produce NOS isoforms, and it has been reported that bacteria also produce NOS [29][30][31][32].…”

mentioning

confidence: 99%

nNOS inhibition, antimicrobial and anticancer activity of the amphibian skin peptide, citropin 1.1 and synthetic modifications

Doyle

Brinkworth

Wegener

et al. 2003

European Journal of Biochemistry

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A large number of bioactive peptides have been isolated from amphibian skin secretions. These peptides have a variety of actions including antibiotic and anticancer activities and the inhibition of neuronal nitric oxide synthase. We have investigated the structure-activity relationship of citropin 1.1, a broad-spectrum antibiotic and anticancer agent that also causes inhibition of neuronal nitric oxide synthase, by making a number of synthetically modified analogues. Citropin 1.1 has been shown previously to form an amphipathic a-helix in aqueous trifluoroethanol. The results of the structure-activity studies indicate the terminal residues are important for bacterial activity and increasing the overall positive charge, while maintaining an amphipathic distribution of residues, increases activity against Gram-negative organisms. Anticancer activity generally mirrors antibiotic activity suggesting a common mechanism of action. The N-terminal residues are important for inhibition of neuronal nitric oxide synthase, as is an overall positive charge greater than three. The structure of one of the more active synthetic modifications (A4K14-citropin 1.1) was determined in aqueous trifluoroethanol, showing that this peptide also forms an amphipathic a-helix.

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Methylesters ofl-Arginine andN-Nitro-l-arginine Induce Nitric Oxide Synthase inStaphylococcus aureus

Cited by 17 publications

References 18 publications

Nitric Oxide is Involved in the Azospirillum brasilense-induced Lateral Root Formation in Tomato

Nitric Oxide is Involved in the Azospirillum brasilense-induced Lateral Root Formation in Tomato

Amphibian peptides that inhibit neuronal nitric oxide synthase

nNOS inhibition, antimicrobial and anticancer activity of the amphibian skin peptide, citropin 1.1 and synthetic modifications

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