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Background/Aims: Preterm birth (PTB) and low birth weight (LBW) significantly influence mortality and morbidity of the offspring in early life and also have long-term consequences in later life. A better understanding of the molecular mechanisms of preterm birth could provide new insights regarding putative preventive strategies. Metabolomics provides a powerful analytic tool to readout complex interactions between genetics, environment and health and may serve to identify relevant biomarkers. In this study, the association between 163 targeted maternal blood metabolites and gestational age was investigated in order to find candidate biomarkers for PTB. Methods: Five hundred twenty-three women were included into this observational study. Maternal blood was obtained before delivery. The concentration of 163 maternal serum metabolites was measured by flow injection tandem mass spectrometry. To find putative biomarkers for preterm birth, a three-step analysis was designed: bivariate correlation analysis followed by multivariable regression analysis and a comparison of mean values among gestational age groups. Results: Bivariate correlation analysis showed that 2 acylcarnitines (C16:2, C2), 1 amino acids (xLeu), 8 diacyl-PCs (PCaaC36:4, PCaaC38:4, PCaaC38:5, PCaaC38:6, PCaaC40:4, PCaaC40:5, PCaaC40:6, PCaaC42:4), and 1 Acylalkyl-PCs (PCaeC40:5) were inversely correlated with gestational age. Multivariable regression analysis confounded for PTB history, maternal body mass index (BMI) before pregnancy, systolic blood pressure at the third trimester, and maternal body weight at the third trimester, showed that the diacyl-PC PCaaC38:6 was the only metabolite inversely correlated with gestational age. Conclusions: Maternal blood concentrations of PCaaC38:6 are independently associated with gestational age. (C) 2016 The Author(s) Published by S. Karger AG, Basel
The lakes in the Kenyan Rift Valley offer the unique opportunity to study a wide range of hydrochemical environmental conditions, ranging from freshwater to highly saline and alkaline lakes. Because little is known about the hydro- and biogeochemical conditions in the underlying lake sediments, it was the aim of this study to extend the already existing data sets with data from porewater and biomarker analyses. Additionally, reduced sulphur compounds and sulphate reduction rates in the sediment were determined. The new data was used to examine the anthropogenic and microbial influence on the lakes sediments as well as the influence of the water chemistry on the degradation and preservation of organic matter in the sediment column. The lakes discussed in this study are: Logipi, Eight (a small crater lake in the region of Kangirinyang), Baringo, Bogoria, Naivasha, Oloiden, and Sonachi.
The biomarker compositions were similar in all studied lake sediments; nevertheless, there were some differences between the saline and freshwater lakes. One of those differences is the occurrence of a molecule related to β-carotene, which was only found in the saline lakes. This molecule most likely originates from cyanobacteria, single-celled organisms which are commonly found in saline lakes. In the two freshwater lakes, stigmasterol, a sterol characteristic for freshwater algae, was found. In this study, it was shown that Lakes Bogoria and Sonachi can be used for environmental reconstructions with biomarkers, because the absence of oxygen at the lake bottoms slowed the degradation process. Other lakes, like for example Lake Naivasha, cannot be used for such reconstructions, because of the large anthropogenic influence. But the biomarkers proved to be a useful tool to study those anthropogenic influences. Additionally, it was observed that horizons with a high concentration of elemental sulphur can be used as temporal markers. Those horizons were deposited during times when the lake levels were very low. The sulphur was deposited by microorganisms which are capable of anoxygenic photosynthesis or sulphide oxidation.