Biological and chemical endpoints were measured in white sucker collected downstream of Athabasca oil sands developments (AB, Canada) and compared with those at Calling Lake (AB, Canada), a reference location upstream of the Athabasca oil sands deposit. Naphthenic acid concentrations were also measured at 14 sites in the Athabasca River watershed. Concentrations of naphthenic acids were elevated in tributaries adjacent to oil sands mining developments. Tributary naphthenic acid profiles were more similar to aged oil sands process water than samples from the Athabasca River, suggesting an influence of tailings in the tributaries. White sucker showed higher energy storage in the Athabasca River as indicated by significantly higher condition and liver size. White sucker were not investing that energy into reproductive effort as measured by gonad size and fecundity, which were significantly reduced relative to the reference location. White sucker showed increased exposure to polycyclic aromatic hydrocarbons as indicated by hepatic cytochrome P4501A (CYP1A) activity and fluorescent bile metabolites, as well as higher concentrations of naphthenic acids in bile. Cadmium, copper, nickel, and selenium were also elevated in white sucker liver tissue compared with the reference location. Based on the exposure profile and response pattern observed, effects on energy storage and utilization in white sucker from the Athabasca River most likely resulted from exposure to polycyclic aromatic hydrocarbons derived from petrogenic and pyrolytic sources. Environ Toxicol Chem 2017;36:2058-2067. © 2017 SETAC.

A new lipopeptide, cystargamide (1) was isolated from the fermentation broth of the actinomycete Kitasatospora cystarginea. The bacterial strain was selected from a set of 12 Kitasatospora spp. using a secondary metabolomics approach combining liquid chromatography/high-resolution mass spectrometry (LC-HRMS) with principal component analysis (PCA). Cystargamide (1) was purified by reversed-phase HPLC, and the structure elucidation was achieved by interpreting mass spectrometry and NMR data. Cystargamide (1) contains rare structural features including a 5-hydroxy tryptophan residue and a 2,3-epoxydecanoyl fatty acid group.

Two novel β-lactone-containing natural products, cystargolides A (1) and B (2), were isolated from the actinomycete Kitasatospora cystarginea. The production of these two natural products was highlighted using a methodology associating liquid chromatography-high-resolution mass spectrometry (LC-HRMS) analysis and the statistical analysis tool principal component analysis (PCA). Their structures were elucidated by interpretation of NMR experiments and tandem mass spectrometry. The absolute configurations of the amino acid residues were determined using Marfey's method, and the relative configurations of the β-lactone substituents were determined on the basis of the vicinal (3)J(HH) coupling value. Due to the presence of the β-lactone, 1 and 2 were evaluated for their ability to inhibit the human 20S proteasome. 1 and 2 both inhibited the 20S proteasome in vitro with IC50 values of 0.35 and 0.93 μM, respectively.

Satosporins A and B, two novel glucosylated polyketides, were isolated from the actinomycete Kitasatospora griseola MF730-N6. The polyketides possess an unprecedented tricyclic ring system that was fully characterized using a combination of spectroscopic analyses and computational calculations. Satosporin A was quantitatively converted into its aglycon homologue, satosporin C, using a β-glucosidase. The determination of the absolute stereochemistry was achieved using solution TDDFT/ECD calculations and chemical derivatization methods.

We report here the draft genome sequence of Kitasatospora griseola strain MF730-N6, a known producer of bafilomycin, terpentecin, and satosporins. The current assembly comprises 8 contigs covering 7.97 Mb. Genome annotation revealed 7,225 protein coding sequences, 100 tRNAs, 40 rRNA genes, and 23 secondary metabolite biosynthetic gene clusters.

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