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Compound-specific δ<sup>13</sup>C analyses reveal sterol metabolic constraints in an aquatic invertebrate

Compound-specific δ13C analyses reveal sterol metabolic constraints in an aquatic invertebrate

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Prüfsumme: MD5:11009704f0f9da6365438553c9daf2eb

GERGS, René, Nicole STEINBERGER, Birgit BECK, Timo BASEN, Elizabeth YOHANNES, Ralf SCHULZ, Dominik MARTIN-CREUZBURG, 2015. Compound-specific δ13C analyses reveal sterol metabolic constraints in an aquatic invertebrate. In: Rapid Communications in Mass Spectrometry. 29(19), pp. 1789-1794. ISSN 0951-4198. eISSN 1097-0231. Available under: doi: 10.1002/rcm.7279

@article{Gergs2015Compo-32061, title={Compound-specific δ13C analyses reveal sterol metabolic constraints in an aquatic invertebrate}, year={2015}, doi={10.1002/rcm.7279}, number={19}, volume={29}, issn={0951-4198}, journal={Rapid Communications in Mass Spectrometry}, pages={1789--1794}, author={Gergs, René and Steinberger, Nicole and Beck, Birgit and Basen, Timo and Yohannes, Elizabeth and Schulz, Ralf and Martin-Creuzburg, Dominik} }

RATIONALE: Dietary sterol deficiencies can have severe life history consequences for consumers. Compound-specific stable isotope analysis (CSIA) was applied to the exploration of the sterol metabolic constraints and bioconversion capacities of the amphipod Gammarus roeselii. Evaluating structural sterol requirements has great potential to improve our understanding of the ecological relevance of sterols as limiting nutrients.<br /><br />METHODS: Juvenile G. roeselii were reared on food mixtures consisting of different ratios of the two algae Scenedesmus obliquus (cultivated with <sup>13</sup>C-labeled NaHCO<sub>3</sub>) and Nannochloropsis limnetica (unlabeled), which have been shown previously to differ in food quality. We measured the sterol content and composition using a gas chromatograph equipped with a flame ionization detector and the δ<sup>13</sup>C values of sterols using compound-specific isotope ratio mass spectrometry to examine potential sterol-mediated nutritional constraints of G. roeselii.<br /><br />RESULTS: In the food mixtures, δ<sup>13</sup>C values of cholesterol, synthesized by N. limnetica, were 25‰and those of the Δ<sup>7</sup>-phytosterols, chondrillasterol and fungisterol, synthesized by S. obliquus, were 7 and 18‰, respectively. Although the cholesterol concentrations in G. roeselii decreased with increasing proportion of dietary S. obliquus, the δ<sup>13</sup>C values remained constant at 25‰. Lathosterol, which appeared in G. roeselii at high dietary proportions of S. obliquus, had a δ<sup>13</sup>C value of 35‰.<br /><br />CONCLUSIONS: We provide evidence that the the Δ<sup>7</sup>-phytosterols present in S. obliquus cannot be metabolized to cholesterol in G. roeselii, resulting in the accumulation of lathosterol in the animals and potentially in sterol-limited growth. These findings emphasize the advantage of CSIA in revealing the physiological mechanisms associated with nutritional constraints. Gergs, René Martin-Creuzburg, Dominik Schulz, Ralf Steinberger, Nicole eng Basen, Timo Martin-Creuzburg, Dominik Beck, Birgit Yohannes, Elizabeth Compound-specific δ<sup>13</sup>C analyses reveal sterol metabolic constraints in an aquatic invertebrate 2015-11-04T14:09:55Z Yohannes, Elizabeth 2015 Steinberger, Nicole Gergs, René 2015-11-04T14:09:55Z Beck, Birgit Schulz, Ralf Basen, Timo

Dateiabrufe seit 04.11.2015 (Informationen über die Zugriffsstatistik)

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