Mass spectrometry ofAlternaria mali toxins and related cyclodepsipeptides

Ueno, Tamio; Nakashima, Torahiko; Uemoto, Miyuki; Fukami, Hiroshi; Lee, Sang-Nam; Izumiya, Nobuo

doi:10.1002/bms.1200040303

Cited by 27 publications

(13 citation statements)

References 6 publications

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“…1) in the pioneering work on structural elucidation of HSTs (Okuno et al, 1974;Ueno et al, 1975Ueno et al, , 1977. 1) in the pioneering work on structural elucidation of HSTs (Okuno et al, 1974;Ueno et al, 1975Ueno et al, , 1977.…”

Section: Chemical Structures Of Alternaria Hstsmentioning

confidence: 99%

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Host-selective toxins produced by the plant pathogenic fungusAlternaria alternata

et al. 2013

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Host-selective toxins (HSTs) produced by fungal plant pathogens are generally low-molecular-weight secondary metabolites with a diverse range of structures that function as effectors controlling pathogenicity or virulence in certain plant-pathogen interactions. There are now seven known diseases caused by Alternaria alternata in which HSTs are responsible for fungal pathogenesis. The pathogens have been defined as pathotypes of A. alternata because of morphological similarity but pathological differences. Chemical structures of HSTs from six pathotypes have been determined. The role of A. alternata HSTs in pathogenesis has been studied extensively, and discovery of the release of HSTs from germinating conidia prior to penetration aids in understanding the early participation of HSTs to induce susceptibility of host cells by suppressing their defence reactions. Many attempts have been made to find the target sites of A. alternata HSTs, and four cellular components, plasma membrane, mitochondrion, chloroplast and a metabolically important enzyme, have been identified as the primary sites of each HST action, leading to elucidation of the molecular mechanisms of HST sensitivity in host plants. Studies of the molecular genetics of HST production have identified supernumerary chromosomes encoding HST gene clusters and have provided new insights into the evolution of A. alternata pathotypes.

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Section: Chemical Structures Of Alternaria Hstsmentioning

confidence: 99%

“…The apple pathotype produces cyclic peptide AM-toxins (Okuno et al, 1974;Ueno et al, 1975Ueno et al, , 1977. Cyclic peptides are generally synthesized via non-ribosomal pathways by large multifunctional enzymes called nonribosomal peptide synthetases (NRPS), which have highly conserved domains (Keller et al, 2005).…”

Section: Am-toxinmentioning

confidence: 99%

Host-selective toxins produced by the plant pathogenic fungusAlternaria alternata

et al. 2013

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“…The apple pathotype produces cyclic depsipeptide AM-toxins ( Fig. 1b) (Okuno et al 1974;Ueno et al 1977) and causes Alternaria blotch, a disease of worldwide importance, on apple cultivars susceptible to AM-toxins (Sawamura 1990;Filajdić and Sutton 1991). We found similarity in the structures of AF-toxin I and the AM-toxins.…”

Section: Introductionmentioning

confidence: 80%

“…1b), with toxin I being the predominant species with respect both to yield and to biological activity (Okuno et al 1974;Kohmoto et al 1977;Ueno et al 1977). AM-toxin I in the cultures of the single-copy mutants was quantified by reverse-phase HPLC.…”

Section: Am-toxin Production and Pathogenicity Of The Amt2 Single-copmentioning

confidence: 99%

Multiple copies of AMT2 are prerequisite for the apple pathotype of Alternaria alternata to produce enough AM-toxin for expressing pathogenicity

et al. 2008

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The apple pathotype of Alternaria alternata produces the cyclic depsipeptide AM-toxin and causes Alternaria blotch of apple. Previously, we cloned AMT2 from the apple pathotype as an orthologue of AFTS1, which is required for biosynthesis of the decatrienoic acid ester AF-toxin I of the strawberry pathotype. These genes were predicted to encode aldo-keto reductases involved in biosynthesis of a common precursor, 2-hydroxy-isovaleric acid, of AF-toxin I and AM-toxin. In this study, we analyzed the function of AMT2 in AM-toxin biosynthesis in the apple pathotype. DNA gel blot analysis of the apple pathotype strain IFO8984 with five restriction enzymes suggested that this strain has a single copy of AMT2 in the genome. However, gene disruption experiments showed that IFO8984 probably has three copies of AMT2. We made mutants having one or two copies of AMT2 disrupted. The single-copy mutants produced less AM-toxin than did the wild type and were still as pathogenic as the wild type. The two-copy mutants produced trace or undetectable amounts of AM-toxin and were markedly reduced in pathogenicity. Thus, AMT2 was verified to be required for AM-toxin biosynthesis and hence pathogenicity. The fact that the two-copy mutants have a remaining copy of AMT2 suggests that multiple copies of AMT2 are prerequisite for the pathogen to produce enough AM-toxin for full pathogenicity.

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“…2; Table 2) AM-toxin (19), a phytotoxic compound, was obtained from the apple pathotype of Alternaria alternata and gave rise to Alternaria blotch of apple [34,35]. Previous evaluation showed that the inhibitory activity of numerous AM-toxin analogues against photosynthesis is correlated with their necrosis-inducing activity [36].…”

Section: Introductionmentioning

confidence: 99%

Medicinal significance of naturally occurring cyclotetrapeptides

Abdalla

2016

J Nat Med

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Bioactive natural products are serendipitous drug candidates, which stimulate synthetic approaches for improving and supporting drug discovery and development. Therefore, the search for bioactive metabolites from different natural sources continues to play an important role in fashioning new medicinal agents. Several cyclic peptides were produced by organisms, such as b-defensins, gramicidin S, and tyrocidine A, and exhibited a wide range of bioactivities, such as antiviral activity against HIV-1, influenza A viruses, or antibacterial activity. Cyclic tetrapeptides are a class of natural products that were found to have a broad range of biological activities, promising pharmacokinetic properties, as well as interesting conformational dynamics and ability of slow inter-conversion to several different structures. Cyclooligopeptides, particularly medium ring-sized peptides, were obtained from marine microorganisms and exhibited a wide range of pharmacological properties, including antimicrobial and anti-dinoflagellate activities, cytotoxicity, and inhibitory activity against enzyme sortase B. Most of the naturally occurring cyclotetrapeptides are obtained from fungi. Some natural cyclic tetrapeptides were found to inhibit histone deacetylase (HDAC), which regulate the expression of genes. These compounds are very useful as cancer therapeutics. Various analogues of the natural cyclotetrapeptides were successfully synthesized to find novel lead compounds for pharmacological and biotechnological applications. Therefore, in this review, previously reported novel natural cyclotetrapeptides are briefly discussed, along with their important biological activities as drug candidates, together with their promising therapeutic properties. Moreover, their future perspective in drug discovery as potential therapeutic agents will be determined.

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Mass spectrometry ofAlternaria mali toxins and related cyclodepsipeptides

Cited by 27 publications

References 6 publications

Host-selective toxins produced by the plant pathogenic fungusAlternaria alternata

Host-selective toxins produced by the plant pathogenic fungusAlternaria alternata

Multiple copies of AMT2 are prerequisite for the apple pathotype of Alternaria alternata to produce enough AM-toxin for expressing pathogenicity

Medicinal significance of naturally occurring cyclotetrapeptides

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