Metabolites from freshwater aquatic microalgae and fungi as potential natural pesticides

Abstract

Microorganisms are recognized worldwide as the major source of secondary metabolites with mega diverse structures and promissory biological activities. However, as yet many of them remain little or under-explored like the microbiota from freshwater aquatic ecosystems. In the present review, we undertook a recompilation of metabolites reported with pesticidal properties from microalgae (cyanobacteria and green algae) and fungi, specifically from freshwater aquatic habitats.

Acetophenone derivatives from a freshwater fungal isolate of recently described Lindgomyces madisonensis (G416)

“…While knowledge regarding the distribution patterns and taxonomy has increased for this ecological group of fungi due to intensive collection over the last two decades, their chemistry, particularly regarding secondary metabolites, has had limited investigation (Hosoe et al, 2010, Jiao et al, 2006, Li et al, 2003, Mudur et al, 2006, Oh et al, 1999, Reategui et al, 2005. As of 2011, approximately 127 chemical structures had been reported from about 30-40 freshwater fungal species (El-Elimat et al, 2014a, El-Elimat et al, 2014b, Hernández-Carlos and Gamboa-Angulo, 2011. To ameliorate this knowledge gap, studies were initiated on the chemical mycology of freshwater ascomycetes in North Carolina, USA (El-Elimat et al, 2014a, El-Elimat et al, 2014b, Raja et al, 2013a, Raja et al, 2013b, representing the first systematic study of freshwater ascomycetes from this region of North America.…”

An overview of the potential environmental impacts of large-scale microalgae cultivation

“…Pesticides contain organochlorine compounds which, as mentioned above, lead to ozone destruction in Downloaded by [University of Leeds] at 08:18 21 July 2014 the stratosphere [124]. However, it would be expected that the use of pest control would be lower compared with terrestrial agricultural crops [12] as some species produce metabolites that act as natural pest control mechanisms [125].…”

“…A study used seawater to cultivate N. Salina in raceways and PBRs in Brazil, and found PBRs consumed over 15 times more energy for water pumping and cooling than raceways [136]. Other cultivation systems include algal turf scrubbers (water filtering devices used to cultivate algae) which are operated at full scale for wastewater [61,121,125,126] treatment using filamentous algae, biofilm designs which aim to reduce energy and water use [141,142] and heterotrophic fermentation systems. These are emerging technologies and are beyond the scope of this review.…”

α-Pyrone derivatives, tetra/hexahydroxanthones, and cyclodepsipeptides from two freshwater fungi

“…6 Freshwater fungi represent a potentially rich, although poorly studied, source of new mycological and chemical diversity. 7,8 While working in the Lake Brandt watershed of Greensboro, NC, two related freshwater fungal species, belonging to the genus Clohesyomyces, were isolated from submerged wood and accessioned as G100 and G102. Fungal strain G102 biosynthesized 18 compounds belonging to three distinct classes of natural products.…”

“…Fungal strain G102 biosynthesized 18 compounds belonging to three distinct classes of natural products. Twelve were members of the α-pyrone class of secondary metabolites (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), of which five were known [phomopsinone A (1), phomopsinone B (2), phomopsinone C (3), pyrenocine M (4), and pyrenocine K (5)] and seven were new [6hydroxy-7-epi-phomopsinone A (6), 5-deoxy-7hyrdoxypyrenocine M (7), pyrenocine P (8), 7hyrdoxypyrenocine M (9), pyrenocine Q (10), pyrenocine R (11), 5-hydroxyphomopsinone A (12)]. Alternatively, four metabolites were tetra/hexahydroxanthones (13)(14)(15)(16), of which one was the known homodimeric tetrahydroxanthone, secalonic acid A (13), another was a new natural monomeric tetrahydroxanthone [8-hydroxyblennolide H (14)], and two were new monomeric hexahydroxanthones [cis-dihydro-8-hydroxyblennolide H (15) and trans-dihydro-8-hydroxyblennolide H (16)].…”