The constitution of cochliobolin

Canonica, L.; Fiecchi, Alberto; Kienle, Marzia Galli; Scala, Antonio

doi:10.1016/s0040-4039(00)72395-1

Cited by 42 publications

(39 citation statements)

References 1 publication

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“…The identities of all four compounds were confirmed by 'H NMR, UV, and IR spectra, and exact mass determinations, which agree very well with published data (2,3,14 (Fig. 1).…”

Section: Materials Andsupporting

confidence: 88%

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Role of Calmodulin Inhibition in the Mode of Action of Ophiobolin A

Leung¹,

Taylor²,

Wang³

et al. 1985

Plant Physiol.

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Calmodulin has been isolated from the root of Zea mays. It activates the bovine brain calmodulin-dependent cyclic nucleotide phosphodiesterase and has electrophoretic mobility very similar to that of bovine brain calmodulin. Ophiobolin A, a fungal toxin, interacts with the maize calmodulin. The interaction is not reversed by dilution or denaturation in SDS and results in the loss of ability of the calmodulin to activate the phosphodiesterase. The inhibition is much faster in the presence than in the absence of Ca2". The electrophoretic mobility of ophiobolin A-treated calmodulin is less than that of untreated calmodulin. Several similarities are found between the inhibition of maize calmodulin by ophiobolin A in vitro and the effects of ophiobolin A on excised roots. Both are irreversible and time-dependent. The concentration of ophiobolin A for halfmaximal inhibition of calmodulin in the phosphodiesterase assay is similar to that for phytotoxicity. In both cases ophiobolin A derivatives behave similarly, i.e. 18-bromo-19-methoxyophiobolin A is as potent as ophiobolin A, while 3-anhydro-ophiobolin A and 6-epi-ophiobolin A are less potent. A smaller amount of active calmodulin was measured in the extract from ophiobolin A-treated roots than in those from untreated roots. The present study suggests that calmodulin is a target molecule in the root for the toxicity of ophiobolin A. Ophiobolin A is a non-host-specific phytotoxin first isolated from Helminthosporium oryzae, the fungus that causes brown spot disease of rice (15,17). It is one of a series of closely related sesterterpenes, whose occurrence and properties have been reviewed (2, 8). During studies of the host-specific toxin produced by race T of Helminthosporium maydis Nisikado and Miyake (Cochliobolus heterostrophus), it was found that some of the toxic effects of impure preparations of the host-specific toxin could be accounted for by ophiobolin A, which is also produced by this organism (19). Evidence has been reported for a role for ophiobolin A in the production of disease symptoms during the infection of rice by H. oryzae (6). Ophiobolin A has also been identified as an 'aversion factor' produced by Cochliobolus setariae (16). Isolation of Maize Root Calmodulin. Corn seeds were germinated and the seedlings grown in the dark for 6 d at 29°C on paper towels soaked with 0.1 mm CaC12 and 0.5 mM KCL. The roots were excised and rinsed five times with cold deionized, distilled H20 and then homogenized in a Waring Blendor in 50 mM Tris-HCl, 1 mM EDTA, 1 mM 2-mercaptoethanol, 0.6 mM PMSF (pH 7.0) (1 ml/g tissue). The homogenate was filtered through four layers of cheesecloth on ice. The filtrate was centrifuged at 10,000g for 0.5 h at 4°C. The resulting supernatant was applied to a DEAE-cellulose column pre-equilibrated with buffer A (20 mM Tris-HCl, 1 mM Mg(acetate)2, 1 mM imidazole, 1 mM EGTA, 1 mM 2-mercaptoethanol, pH 7.0). The

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“…The identities of all four compounds were confirmed by 'H NMR, UV, and IR spectra, and exact mass determinations, which agree very well with published data (2,3,14 (Fig. 1).…”

Section: Materials Andsupporting

confidence: 88%

“…Briefly, the activity of the PDE was coupled to that of the 5'-nucleotidase. The [3]) when examined by TLC in 8% (v/v) acetone in methylene chloride showed one major spot and a very small amount of material streaking up from the starting point.…”

Section: Materials Andmentioning

confidence: 99%

Role of Calmodulin Inhibition in the Mode of Action of Ophiobolin A

Leung¹,

Taylor²,

Wang³

et al. 1985

Plant Physiol.

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“…The shoots of treated rice seedlings became chlorotic within 24 hr as contrasted to wilting induced by fusicoccin under similar donditions (72). The abso.Jute structure of Ophiobolin A was deduced by X-ray crystallographic analysis by Nozoe et al (71) and confirmed by Canonica et al (20). Ophiobolin A ( Figure 3) has a basic terpenoid structure with an eight.-membered ring, making it similar in respect to fuscicoccin.…”

Section: Ophiobolinsmentioning

confidence: 80%

Phytotoxins Produced by Plant Parasites

Strobel¹

1974

Annu. Rev. Plant. Physiol.

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“…In contrast, the metabolite with structure II has been isolated and identified by CANONICA et al (8) as the oxidation product from 4-methylcatechol by Pseudomonas desmolyticum. They showed that the product, 5-formyl-2-hydroxy-2, 4-hexadienoic acid as shown in structure II gives absorption maximum at 291 m,u (E, 13500) in methanol and mp 160-165°.…”

Section: Oxidation Of 4-methylcatecholmentioning

confidence: 99%

“…Recently, CANONICA et al (8) identified a substituted muconic semialdehyde, which was an intermediary metabolite of 4-methylcatechol by Ps~udomonas desmolyticum, as 5-formyl-2-hydroxy-2, 4-hexadienoic acid.…”

mentioning

confidence: 99%

Oxidation of Phenols by Yeast

Hashimoto

1970

J. Gen. Appl. Microbiol.

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The constitution of cochliobolin

Cited by 42 publications

References 1 publication

Role of Calmodulin Inhibition in the Mode of Action of Ophiobolin A

Role of Calmodulin Inhibition in the Mode of Action of Ophiobolin A

Phytotoxins Produced by Plant Parasites

Oxidation of Phenols by Yeast

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