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Comparative analyses determined the relationship between the structure of bisphenol A (BPA) as well as of seven bisphenol analogues (bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bisphenol F (BPF), bisphenol Z (BPZ), bisphenol AP (BPAP), bisphenol PH (BPPH)) and their biotransformability by the biphenyl-degrading bacterium Cupriavidus basilensis SBUG 290. All bisphenols were substrates for bacterial transformation with conversion rates ranging from 6 to 98% within 216 h and 36 different metabolites were characterized. Transformation by biphenyl-grown cells comprised four different pathways: (a) formation of ortho-hydroxylated bisphenols, hydroxylating either one or both phenols of the compounds; (b) ring fission; (c) transamination followed by acetylation or dimerization; and (d) oxidation of ring substituents, such as methyl groups and aromatic ring systems, present on the 3-position. However, the microbial attack of bisphenols by C. basilensis was limited to the phenol rings and its substituents, while substituents on the carbon bridge connecting the rings were not oxidized. All bisphenol analogues with modifications at the carbon bridge could be oxidized up to ring cleavage, while substituents at the 3-position of the phenol ring other than hydroxyl groups did not allow this reaction. Replacing one methyl group at the carbon bridge of BPA by a hydrophobic aromatic or alicyclic ring system inhibited both dimerization and transamination followed by acetylation. While most of the bisphenol analogues exhibited estrogenic activity, four biotransformation products tested were not estrogenically active. Electronic supplementary material The online version of this article (10.1007/s00253-020-10406-4) contains supplementary material, which is available to authorized users.

The use of oral contraceptives (OCs) has been associated with elevated blood cortisol concentrations. However, metabolic downstream effects of OC intake are not well described. Here, we aimed to determine if the blood metabolome is associated with the use of OCs and to estimate if these associations might be statistically mediated by serum cortisol concentrations. Plasma metabolites measured with the Biocrates AbsoluteIDQ p180 Kit and serum cortisol concentrations measured by an immunoassay were determined in 391 premenopausal women (116 OC users) participating in two independent cohorts of the Study of Health in Pomerania (SHIP). After correction for multiple testing, 27 metabolites were significantly associated with OC intake in SHIP-TREND (discovery cohort), of which 25 replicated in SHIP-2. Inter alia, associated metabolites included 12 out of 38 phosphatidylcholines with diacyl residue, 7 out of 14 lysophosphatidylcholines and 5 out of 21 amino acids. The associations with phosphatidylcholines were statistically mediated by cortisol, whereas lysophosphatidylcholines showed no mediation effect. The results represent a step toward a better understanding of the metabolic consequences of OC intake. Connecting cortisol with metabolic consequences of OC intake could help to understand the mechanisms underlying adverse effects. The blood metabolome may serve as a biomarker for identifying users at high risk for developing such adverse effects.

Comparative analyses determined the relationship between the structure of bisphenol A (BPA) as well as of seven bisphenol analogues (bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bisphenol F (BPF), bisphenol Z (BPZ), bisphenol AP (BPAP), bisphenol PH (BPPH)) and their biotransformability by the biphenyl-degrading bacterium Cupriavidus basilensis SBUG 290. All bisphenols were substrates for bacterial transformation with conversion rates ranging from 6 to 98% within 216 h and 36 different metabolites were characterized. Transformation by biphenyl-grown cells comprised four different pathways: (a) formation of ortho-hydroxylated bisphenols, hydroxylating either one or both phenols of the compounds; (b) ring fission; (c) transamination followed by acetylation or dimerization; and (d) oxidation of ring substituents, such as methyl groups and aromatic ring systems, present on the 3-position. However, the microbial attack of bisphenols by C. basilensis was limited to the phenol rings and its substituents, while substituents on the carbon bridge connecting the rings were not oxidized. All bisphenol analogues with modifications at the carbon bridge could be oxidized up to ring cleavage, while substituents at the 3-position of the phenol ring other than hydroxyl groups did not allow this reaction. Replacing one methyl group at the carbon bridge of BPA by a hydrophobic aromatic or alicyclic ring system inhibited both dimerization and transamination followed by acetylation. While most of the bisphenol analogues exhibited estrogenic activity, four biotransformation products tested were not estrogenically active.

The biphenyl-degrading Gram-negative bacterium Cupriavidus basilensis (formerly Ralstonia sp.) SBUG 290 uses various aromatic compounds as carbon and energy sources and has a high capacity to transform bisphenol A (BPA), which is a hormonally active substance structurally related to biphenyl. Biphenyl-grown cells initially hydroxylated BPA and converted it to four additional products by using three different transformation pathways: (a) formation of multiple hydroxylated BPA, (b) ring fission, and (c) transamination followed by acetylation or dimerization. Products of the ring fission pathway were non-toxic and all five products exhibited a significantly reduced estrogenic activity compared to BPA. Cell cultivation with phenol and especially in nutrient broth (NB) resulted in a reduced biotransformation rate and lower product quantities, and NB-grown cells did not produce all five products in detectable amounts. Thus, the question arose whether enzymes of the biphenyl degradation pathway are involved in the transformation of BPA and was addressed by proteomic analyses.

A bacterial strain with the ability to transform bisphenol A (BPA) and other so-called “new-generation bisphenols” like bisphenol C (BPC), bisphenol E (BPE), bisphenol F (BPF) and bisphenol Z (BPZ) was isolated from sewage sludge and identified as Bacillus amyloliquefaciens. We investigated the biotransformation of bisphenols and analyzed the toxicity and estrogenicity of the products formed compared to the parent compounds. During the incubation of this bacterial strain with different bisphenols one major metabolite was detected in each case by HPLC but its formation was partly reversible. Highest transformation rate of 77% of the initial concentration applied was determined for BPA and BPE. Mass spectrometric and nuclear magnetic resonance spectroscopic analyses as well as deconjugation experiments proofed the formation of phosphate conjugates with each bisphenol. The conjugates formed were considerably less toxic and less estrogenically active than their parent bisphenols.

Background and AimsExaggerated hepatic triglyceride accumulation (i.e., hepatic steatosis) represents a strong risk factor for type 2 diabetes mellitus and cardiovascular disease. Despite the clear association of hepatic steatosis with impaired insulin signaling, the precise molecular mechanisms involved are still under debate. We combined data from several metabolomics techniques to gain a comprehensive picture of molecular alterations related to the presence of hepatic steatosis in a diabetes-free sample (N = 769) of the population-based Study of Health in Pomerania.MethodsLiver fat content (LFC) was assessed using MRI. Metabolome measurements of plasma and urine samples were done by mass spectrometry and nuclear magnetic resonance spectroscopy. Linear regression analyses were used to detect significant associations with either LFC or markers of hepatic damage. Possible mediations through insulin resistance, hypertriglyceridemia, and inflammation were tested. A predictive molecular signature of hepatic steatosis was established using regularized logistic regression.ResultsThe LFC-associated atherogenic lipid profile, tightly connected to shifts in the phospholipid content, and a prediabetic amino acid cluster were mediated by insulin resistance. Molecular surrogates of oxidative stress and multiple associations with urine metabolites (e.g., indicating altered cortisol metabolism or phase II detoxification products) were unaffected in mediation analyses. Incorporation of urine metabolites slightly improved classification of hepatic steatosis.ConclusionsComprehensive metabolic profiling allowed us to reveal molecular patterns accompanying hepatic steatosis independent of the known hallmarks. Novel biomarkers from urine (e.g., cortisol glucuronide) are worthwhile for follow-up in patients suffering from more severe liver impairment compared with our merely healthy population-based sample.

Background Inflammation occurs as an immediate protective response of the immune system to a harmful stimulus, whether locally confined or systemic. In contrast, a persisting, i.e., chronic, inflammatory state, even at a low-grade, is a well-known risk factor in the development of common diseases like diabetes or atherosclerosis. In clinical practice, laboratory markers like high-sensitivity C-reactive protein (hsCRP), white blood cell count (WBC), and fibrinogen, are used to reveal inflammatory processes. In order to gain a deeper insight regarding inflammation-related changes in metabolism, the present study assessed the metabolic patterns associated with alterations in inflammatory markers. Methods Based on mass spectrometry and nuclear magnetic resonance spectroscopy we determined a comprehensive panel of 613 plasma and 587 urine metabolites among 925 apparently healthy individuals. Associations between inflammatory markers, namely hsCRP, WBC, and fibrinogen, and metabolite levels were tested by linear regression analyses controlling for common confounders. Additionally, we tested for a discriminative signature of an advanced inflammatory state using random forest analysis. Results HsCRP, WBC, and fibrinogen were significantly associated with 71, 20, and 19 plasma and 22, 3, and 16 urine metabolites, respectively. Identified metabolites were related to the bradykinin system, involved in oxidative stress (e.g., glutamine or pipecolate) or linked to the urea cycle (e.g., ornithine or citrulline). In particular, urine 3’-sialyllactose was found as a novel metabolite related to inflammation. Prediction of an advanced inflammatory state based solely on 10 metabolites was well feasible (median AUC: 0.83). Conclusions Comprehensive metabolic profiling confirmed the far-reaching impact of inflammatory processes on human metabolism. The identified metabolites included not only those already described as immune-modulatory but also completely novel patterns. Moreover, the observed alterations provide molecular links to inflammation-associated diseases like diabetes or cardiovascular disorders. Electronic supplementary material The online version of this article (doi:10.1186/s12916-017-0974-6) contains supplementary material, which is available to authorized users.

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Serum proteome analysis is severely hampered by the extreme dynamic range of protein concentrations, but tools for the specific depletion of highly abundant serum proteins lack for most farm and companion animals. A well-established alternative strategy to reduce the dynamic range of plasma protein concentrations, treatment with combinatorial peptide ligand libraries (CPLL), is generally applicable but requires large amounts of sample. Therefore, additional depletion/enrichment protocols for plasma and serum samples from animals are desirable. In this respect, we have tested a protein precipitate that formed after withdrawal of salt from human, bovine, or porcine serum at pH 4.2. The bovine sample was composed of over 300 proteins making it a potential source for biomarker discovery. Precipitation was highly reproducible and the concentrations of albumin and other highly abundant serum proteins were strongly reduced. In comparison to the CPLL treatment, precipitation did not introduce any selection bias based on hydrophathy or pI. However, the composition of both preparations was partially complementary. Salt withdrawal at pH 4.2 is suggested as additional depletion/enrichment strategy for serum samples. Also, we point out that the removal of precipitates from serum samples under the described conditions bears the risk of losing a valuable protein fraction.

Membrane envelopment and budding of negative strand RNA viruses (NSVs) is mainly driven by viral matrix proteins (M). In addition, several M proteins are also known to be involved in host cell manipulation. Knowledge about the cellular targets and detailed molecular mechanisms, however, is poor for many M proteins. For instance, Nipah Virus (NiV) M protein trafficking through the nucleus is essential for virus release, but nuclear targets of NiV M remain unknown. To identify cellular interactors of henipavirus M proteins, tagged Hendra Virus (HeV) M proteins were expressed and M-containing protein complexes were isolated and analysed. Presence of acidic leucine-rich nuclear phosphoprotein 32 family member B (ANP32B) in the complex suggested that this protein represents a direct or indirect interactor of the viral matrix protein. Over-expression of ANP32B led to specific nuclear accumulation of HeV M, providing a functional link between ANP32B and M protein. ANP32B-dependent nuclear accumulation was observed after plasmid-driven expression of HeV and NiV matrix proteins and also in NiV infected cells. The latter indicated that an interaction of henipavirus M protein with ANP32B also occurs in the context of virus replication. From these data we conclude that ANP32B is a nuclear target of henipavirus M that may contribute to virus replication. Potential effects of ANP32B on HeV nuclear shuttling and host cell manipulation by HeV M affecting ANP32B functions in host cell survival and gene expression regulation are discussed.

In this study, the bovine plasma proteome was analysed using a three step protocol: (1) plasma was treated with a combinatorial peptide ligand library (CPLL) to assimilate the differences in concentrations of different proteins in raw plasma; (2) CPLL-treated material was fractionated by three standard electrophoretic separation techniques, and (3) samples were analysed by nano-liquid chromatography (nLC) matrix-assisted laser desorption/ionisation (MALDI) time-of-flight tandem (TOF/TOF) mass spectrometry. The efficiencies of three fractionation protocols for plasma proteome analysis were compared. After size fractionation by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), resolution of proteins was better and yields of identified proteins were higher than after charge-based fractionation by preparative gel-free isoelectric focussing. For proteins with isoelectric points >6 and molecular weights ⩾63 kDa, the best results were obtained with a ‘shotgun’ approach, in which the CPLL-treated plasma was digested and the peptides, rather than the proteins, were fractionated by gel-free isoelectric focussing. However, the three fractionation techniques were largely complementary, since only about one-third of the proteome was identified by each approach.