Antiinsectan natural products from fungal sclerotia

Abstract

It is generally accepted that many plants and animals produce and/or sequester metabolites that serve as chemical defenses. By contrast, relatively little is known about chemical defense systems that have evolved among fungi. The fungi are well-known as prolific producers of secondary metabolites,1 but most of these compounds have been discovered through random screening programs, or through studies of mycotoxins that contaminate food supplies of humans and livestock. Fungi commonly thrive in competitive environments, and it is often hypothesized that their secondary metabolic capabilities have been influenced by selection pressures exerted by other organisms. Indeed, fungal metabolites have been implicated in diseases of plants and insects, animal poisonings or intoxications, biocontrol of other fungi, and interspecies antagonism.1 Reports of compounds imparting resistance to fungivory are rare, with most of the known examples coming from basidiomycetes (e.g., mushrooms). Many documented phenomena suggesting the presence of fungal "defensive" substances have never been followed up by chemical investigations.Compelling evidence for the existence of fungal chemical defense systems has been documented and reviewed.2 Mycelia or fruiting structures of various * Phone:

Defining Paxilline Biosynthesis in Penicillium paxilli

“…Total RNA was isolated from frozen mycelium using TRIzol reagent (Invitrogen). Before RT 4 -PCR, isolated RNA was treated with DNase in 50 l reaction volume containing 5 g of RNA, 1ϫ DNase I reaction buffer (Invitrogen) and 5 units of DNase I, amplification grade (Invitrogen), following the manufacturer's instructions. DNA fragments and PCR products were purified using QIAquick gel extraction and a PCR purification kit (Qiagen).…”

“…Most of these metabolites are potent tremorgenic mammalian toxins (3) and some have anti-insect properties (4). Although much work has been done to demonstrate the origins of indole and diterpene components of these metabolites from tryptophan or a tryptophan precursor and mevalonate, respectively (5)(6)(7)(8), very little is known about their biosynthetic pathways.…”

Indoloditerpenes from an algicolous isolate of Aspergillus oryzae

“…[1][2][3]7 In our screening program for biologically active natural products from marine algae and their associated fungi, we have investigated an isolate of the fungus Aspergillus oryzae obtained from the marine red alga Heterosiphonia japonica. Two new indoloditerpene derivatives designated asporyzin A (1) and asporyzin B (2), one new indoloditerpene named asporyzin C (3), and three known indoloditerpenes JBIR-03 (4), 6 emindole SB (5), 5 and emeniveol (6) 4 were isolated and identified from the fungus (Fig.…”

A facial synthesis of quinazolino[1,4]benzodiazepine alkaloids via reductive N-heterocyclization of N-(2-nitrobenzoyl)amides: total synthesis of asperlicin C, circumdatin H, and its analogues

“…[1][2][3][4][5][6] These alkaloids, with diverse biological activities, include asperlicins, [7][8][9] circumdatins, [10][11][12][13] benzomalvins 14 and sclerotigenin. 15,16 Various methods for the synthesis of alkaloids encompassing a quinazolino [1,4]benzodiazepine moiety in their skeleton have been developed and numerous research papers and several reviews have recently appeared. 1,[17][18][19][20][21][22][23][24][25][26][27] The implementations of 2-azidobenzoylamides in aza-Wittig methodology 6,[28][29][30][31][32][33] and transition metalinduced reductive N-heterocyclization [34][35][36][37][38][39] have emerged as versatile strategies for the construction of a variety of heterocyclic compounds.…”