Fungus Helminthosporium

Cytochalasin B Natural product from the fungus Helminthosporium dematioideum (58). Depolymerizes actin hlaments. 

In the course of biosynthetic studies on the antibiotic, siccanin (46), Nozoe et al. have not only isolated trans-y-monocyclofarnesol (47) from the mycelia of the fungus, Helminthosporium siccans, but they have also demonstrated that a cell-free enzymatic preparation from the fungi converts mevalonic acid lactone into (47) in high yield. A key intermediate in the synthesis of abscisic acid is (48), which... 

In 1974 Marumo and coworkers synthesized the enantiomers of JH II by microbial asymmetric hydrolysis of the epoxy ring of ( )-JH II (prepared by Mori) with a fungus Helminthosporium sativum 23 The hydrolysed diol was converted to (+)-JH II, while the epoxide remained intact was (—)-JH II. Their enantiomeric purities, however, were rather low (66-73% ee), and no definite biological data could be obtained. 

Holland et al.1181 obtained the (R)-sulfoxides from various para-substituted phenyl 3-chloropropyl and phenyl 3-hydroxypropyl sulfides by biotransformation with the fungus Mortierella isabellina with an enantiomeric excess of 82-88%. The (S)-sulfoxides were produced using the fungus Helminthosporium sp. and the bacterium Acinetobacter calcoaceticus with ee values of > 95% and 94%, respectively. 

The cis-sativenediol (118) is a metabolite that was isolated from the fungus Helminthosporium sativum [48], Its structure was independently determined by Narumo [49] and Arigoni [50]. The cis-sativenediol (118) which possesses gibberelin-like plant growth promoter activity has been synthesized by Piers [51], McMurry [52] and Matsumoto [53]. The synthesis of cis-sativenediol by McMurry [52] utilizes the Wieland-Miescher ketone (1). The synthetic route is described in "Fig (10)". 

C22H30O3, Mr 342.48, pale yellow cryst., mp. 139-140°C, [a]u -136° (CHClj), soluble in organic solvents. A metabolite from cultures of the phytopath-ogenic fungus Helminthosporium siccans. The strac-ture of S. consists of a drimane sesquiterpene linked to orcinol. S. has broad antifungal activity, especially against Trichophyton species that cause skin infections. 

Baker s yeast (Saccharomyces cerevisiae) contEiins a desaturase which is able to oxidize some almost symmetrical sulfides such as methyl thiostearate [132]. A less symmetrical sulfide. Bn—S—(CH2)t—C02Me, has been oxidized by Saccharomyces cerevisiae into an (S)-sulfoxide with 70% ee. The stereochemical course of the oxidation by 5. cerevisiae of quasisymmetrical sulfides such as methyl 9-thiastearate has been established and found highly enantioselective (>95% ee) [133]. Recently, biosulfoxidation by the fungus Helminthosporium ARRL 4671 has been applied to the synthesis of (R)-(-)-sulforaphane (54a) (Scheme 1.13) [134]. This compound has interesting biological properties. 

Secolongifolene diol is one of the metabolites of the fungus Helminthosporium sativum (725). Recently, a simple synthesis of its optical antipode (193) has been achieved by exploiting the electrophilic addition-fragmentation reaction (726) of homoallylic alcohols. The homoallylic alcohol (191), which can be obtained from longicyclene (44) by cyclo-... 

Heiminthosporal a product of the phytopatho-genic fungus Helminthosporium sativum (= Bipolaris sarokiniana, Shoemaker), which has a physiological effect on plants similar to that of gibberellins. 

Natural Products.— The idant-growth promoter cu-sativenediol, which is produced by certain fungi, has the structure (839) Structures (840) and (841) are assigned to isosativene derivatives isolated from the fungus Helminthosporium sativum. Extraction of the volatile root oil of Angelica archangelica L has yielded the new sesquiterpene alcohol cis-a-copaen-8-ol (842). An alternative synthesis of (843), a key intermediate for the preparation of (+)-sativene and (-I- )-cyclosativene, has been described. Stereoselective syntheses of the two diastereomeric bicyclo[3,2,l]-... 

Natural product HDAC inhibitor Helminthosporium carbonum (HC)-toxin (Fig. 14) is produced from filamentous fungus Cochliobolus carbonum Like chlamydocin, this compound is a cyclic peptide that contains both D- and L-amino acids to relieve ring strain. The epoxy group... 

Erosion and wax degradation also occurs in the cuticle of rice in contact with Helminthosporium oryzae germlings (AA) and the fungus produces excessive amounts of an extracellular matrix around germ tubes and appressoria. The extracellular sheath or matrix also was shown to adhere tenaciously to the cuticle and associated wax components. 

Isoindoles are not known to occur as natural products again, there is a marked contrast with the indoles. However, the cytochalasins, a group of mold metabolites having a marked effect on cell division, contain a highly substituted isoindoline nucleus (3). Cytochalasins A and B (4 and 5) have been obtained from Helminthosporium dematioideum,1 cytochalasins C and D (6 and 7) from Metarrhizium anisopliae,8 and the cytochalasins 8 and 9 from the fungus Phomopsis paspalli found on an Indian millet.9... 

The microbiological oxidation of mitragynine by a Helminthosporium fungus affords two major metabolites, identifiedas mitragynine pseudoindoxyl and hydroxymitragynine pseudoindoxyl. 

A monoprenylhydroquinone, siccayne (139 yellowish prisms extraction yeld 26 mg/ml), was identified from mycelia of the marine Basidimycotina Holocyphina villosa Kohlm. et Kohlm. (Corticiaceae). This fungus is found on mangrove roots and similar substrates in the vicinity of mussels and other marine organisms. Siccayne was formerly isolated from the terrestrial Deuteromycotina Helminthosporium siccans [140,141]. 

Thioacetals have been oxidized to their monosulfoxides by various fungal species with ee s up to 70% [130,131]. This last result was obtained in the oxidation of 2-r-butyl-13-dithiane by Helminthosporium fungus into rra 5-2-r-butyl-l,3-dithiane 1-oxide. 

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