Thus, these isobaric compounds were annotated as putative isomers of a reference compound already described from fungi

Thus, these isobaric compounds were annotated as putative isomers of a reference compound already described from fungi. from the gills, intestine, and muscle tissue of the scallop from NVP-QAV-572 marine farms in Brazil [8]. Sallenave-Namont et al. reported the presence of genera NVP-QAV-572 along with Mucorales from mussel samples from marine shellfish farming areas [6]. In this way, all marine bivalves are colonized by a high diversity of microorganisms and fungi are major contributors to the microbiome of these holobionts. Various lifestyles such as symbiosis, parasitism, and mutualism have been described for fungi, depending on the species and the host [9,10]. In these ecosystems, fungi can establish numerous interactions with their hosts, mediated by secondary metabolites that serve as communication or chemical war purposes [10]. However, while the relationship between plants and endophytic fungi or between animals and fungal parasites have been the object of numerous works, almost no studies have investigated the chemical ecology of the association between mollusc bivalves and associated fungi. is one of the predominant genera in marine environments [11] and shellfish-derived strains have been demonstrated to produce a high range of metabolites. Some of these are identical to compounds from terrestrial origin such as roquefortine C [12], patulin, cladosporin, festuclavin or griseofulvin [13,14], but others have been first detected from marine strains [10]. It seems that under the very specific conditions observed in marine environments, such as pressure, salinity or tides, some chemical pathways or chemical conditions are expressed that Rabbit Polyclonal to GRK5 are not observed in terrestrial media. An conversation with marine invertebrates is usually one further condition that can be supposed to induce a dedicated chemistry. In this way, in a previous work, it was exhibited that strains isolated from shellfish produced more bioactive compounds than strains sampled from their surrounding environment [15,16]. To access metabolites involved in the chemical communication between the two species and whose expression is usually silenced under usual laboratory culture conditions, culture-based strategies such as OSMAC (One Strain Many Compounds) are mandatory [17,18]. As part of this strategy, in vitro cultivation of fungi in the presence of host-derived substrates can induce specific metabolites. For example, the cultivation of a strain on tulip agar led to the medium-dependant production and isolation of the novel metabolites corymbiferone [19] and corymbiferan lactones A-D [20]. Host-derived media have also been successfully applied to enhance the yield of fungal inocula [21,22], to stimulate the production of low abundance metabolites [23], and to promote novel extracellular enzyme production and enhance protein expression [24,25,26,27]. In the marine field, the in vitro cultivation of fungi on mussel-derived substrates has been employed to convert agricultural and marine residues into microbial metabolites [27,28,29,30,31,32], and a recent study showed that mussel-processing wastewaters were a promising nutritive medium for astaxanthin production by the basidiomycetous species [29]. However, very little information is usually available on fungal metabolome expression induced by bivalves. Only one study has shown that the use of a mussel flesh-derived culture medium enhanced the production of cytotoxic metabolites by some mussel-derived fungi [16]. During our ongoing search for new marine fungal natural products, a J.C. Gilman & E.V. Abbott strain was isolated from a mussel sample in the Loire estuary, France. Although it is usually mainly considered as a typical terrestrial ground species, it has also been sampled from seawater, corals and marine sponges [33]. isolates have been shown to produce some bioactive metabolites such as NVP-QAV-572 dehydrocarolic acid, gliotoxin [34], restricticin and its dimethyl derivative [35,36], curvularins [37], calbistrins [38,39], and the mycotoxins patulin and penicillic acid [40]. In this study, we present a metabolome investigation of a mussel-derived strain of MMS417, with a focus on environment-derived culture conditions. Alterations of culture conditions were performed following the OSMAC approach using seven culture media including a host-derived medium to evaluate the influence of mussel components around the production of specialized metabolites. In addition, the effect of salinity was also explored. Culture extracts were submitted to an untargeted metabolomics study using UPLC-IT/ToFCMS/MS-based molecular networking (MN) [41]. This resulted in highlighting some classes of metabolites overexpressed by the presence of mussel and seawater and to the MS-guided isolation of 12 pyran-2-ones including five new fungal natural products. Some of these compounds were tested for cytotoxic, antibacterial,.