Petrogenesis of volcanic rocks from the Quaternary Eifel volcanic fields, Germany: detailed insights from combined trace-element and Sr-Nd-Hf-Pb-Os isotope data.

Quaternary rocks from the East and West Eifel volcanic fields in western Germany are a key suite of intraplate volcanic rocks that can provide insights into volcanism of the Central European Volcanic Province (CEVP) and into continental intraplate volcanism in general. We present a comprehensive dataset for Eifel lavas including isotope as well as major and trace element data for 59 samples covering representative compositions of the different volcanic fields. In line with previous studies, the lavas are all SiO2-undersaturated, alkaline-rich and mainly comprise primitive basanites, melilitites, and nephelinites (Mg# ≥ 57). Geochemical compositions of samples from both volcanic subfields display distinct differences in their trace-element as well as radiogenic isotope compositions, largely confirming previous subdivisions. Coupled trace-element and radiogenic Sr-Nd-Hf-Pb-Os isotope compositions can now provide firm evidence for spatially heterogeneous mantle sources and compositionally distinct magmatic pulses. Within the West Eifel Field, Sr-Nd-Pb isotope compositions of the younger (≤80 ka), ONB-suite (olivine-nephelinite-basanite) are similar to FOZO (FOcal ZOne) or the EAR (European Asthenospheric Reservoir) and resemble compositions that have been previously reported from plume-sourced ocean island basalts (OIB). In marked difference, older (700 Ma to 80 ka) volcanic rocks from the F-suite (Foidite) in the West Eifel field and from the entire east Eifel Field tap a more enriched mantle component, as illustrated by more radiogenic Sr isotope (86Sr/87Sr up to 0.705408) and variable Pb isotope compositions (206Pb/204Pb = 18.61-19.70, 207Pb/204Pb = 15.62-15.67 and 208Pb/204Pb = 38.89-39.76). Combined trace-element compositions of ONB-suite samples are in good agreement with results from batch melting models suggesting a hybrid composition of Eifel magmas formed through mixing 10% of a FOZO-like melt with 90% of a DMM-like melt, similar to melts from the Tertiary HEVF. However, radiogenic Sr-Nd-Pb isotope compositions of F-suite and EEVF and some ONB lavas require the admixture of melts from lithospheric mantle sources. Elevated Nb/Ta and Lu/Hf ratios in combination with variable 187Os/188Os ratios can now demonstrate the presence of residual carbonated eclogite components, either in the lithosphere or in the asthenospheric mantle. Finally, by combining geochemical and temporal constraints of Tertiary and Quaternary volcanism it becomes evident that CEVP volcanism in central and western Germany has resulted from compositionally distinct magmatic pulses that tap separate mantle sources. Although the presence of a mantle plume can neither be fully confirmed nor excluded, plume-like melt pulses which partially tap carbonated eclogite domains that interact to variable extents with the lithosphere provide a viable explanation for the temporal and compositional cyclicity of CEVP volcanism. Supplementary Information: The online version contains supplementary material available at 10.1007/s00410-024-02137-w.

Jahn-Teller Splitting in Single Adsorbed Molecules Revealed by Isospin-Flip Excitations.

Scanning tunneling spectroscopy measurements of Mn phthalocyanine (MnPc) molecules adsorbed on (sqrt[3]×sqrt[3]) surface alloys show single inelastic steps at exclusively positive or negative bias strongly depending on the tip position. This is in contrast to conventional molecular excitation thresholds, which are independent of the current direction and therefore always occur at both positive and negative bias. This polarity selectivity is found to coincide with the spatial distribution of occupied and empty orbitals. Because of the interaction with the substrate, charge transfer into the doubly degenerate d_{π} orbitals of MnPc takes place. The resulting Jahn-Teller effect lifts the degeneracy and leads to an isospin- or pseudospin-flip excitation, the inelastic analogue of an orbital Kondo resonance.

A link between arabinose utilization and oxalotrophy in Bradyrhizobium japonicum.

Rhizobia have a versatile catabolism that allows them to compete successfully with other microorganisms for nutrients in the soil and in the rhizosphere of their respective host plants. In this study, Bradyrhizobium japonicum USDA 110 was found to be able to utilize oxalate as the sole carbon source. A proteome analysis of cells grown in minimal medium containing arabinose suggested that oxalate oxidation extends the arabinose degradation branch via glycolaldehyde. A mutant of the key pathway genes oxc (for oxalyl-coenzyme A decarboxylase) and frc (for formyl-coenzyme A transferase) was constructed and shown to be (i) impaired in growth on arabinose and (ii) unable to grow on oxalate. Oxalate was detected in roots and, at elevated levels, in root nodules of four different B. japonicum host plants. Mixed-inoculation experiments with wild-type and oxc-frc mutant cells revealed that oxalotrophy might be a beneficial trait of B. japonicum at some stage during legume root nodule colonization.

The ethylmalonyl-CoA pathway is used in place of the glyoxylate cycle by Methylobacterium extorquens AM1 during growth on acetate.

Acetyl-CoA assimilation was extensively studied in organisms harboring the glyoxylate cycle. In this study, we analyzed the metabolism of the facultative methylotroph Methylobacterium extorquens AM1, which lacks isocitrate lyase, the key enzyme in the glyoxylate cycle, during growth on acetate. MS/MS-based proteomic analysis revealed that the protein repertoire of M. extorquens AM1 grown on acetate is similar to that of cells grown on methanol and includes enzymes of the ethylmalonyl-CoA (EMC) pathway that were recently shown to operate during growth on methanol. Dynamic 13C labeling experiments indicate the presence of distinct entry points for acetate: the EMC pathway and the TCA cycle. 13C steady-state metabolic flux analysis showed that oxidation of acetyl-CoA occurs predominantly via the TCA cycle and that assimilation occurs via the EMC pathway. Furthermore, acetyl-CoA condenses with the EMC pathway product glyoxylate, resulting in malate formation. The latter, also formed by the TCA cycle, is converted to phosphoglycerate by a reaction sequence that is reversed with respect to the serine cycle. Thus, the results obtained in this study reveal the utilization of common pathways during the growth of M. extorquens AM1 on C1 and C2 compounds, but with a major redirection of flux within the central metabolism. Furthermore, our results indicate that the metabolic flux distribution is highly complex in this model methylotroph during growth on acetate and is fundamentally different from organisms using the glyoxylate cycle.

Oxalyl-coenzyme A reduction to glyoxylate is the preferred route of oxalate assimilation in Methylobacterium extorquens AM1.

Oxalate catabolism is conducted by phylogenetically diverse organisms, including Methylobacterium extorquens AM1. Here, we investigate the central metabolism of this alphaproteobacterium during growth on oxalate by using proteomics, mutant characterization, and (13)C-labeling experiments. Our results confirm that energy conservation proceeds as previously described for M. extorquens AM1 and other characterized oxalotrophic bacteria via oxalyl-coenzyme A (oxalyl-CoA) decarboxylase and formyl-CoA transferase and subsequent oxidation to carbon dioxide via formate dehydrogenase. However, in contrast to other oxalate-degrading organisms, the assimilation of this carbon compound in M. extorquens AM1 occurs via the operation of a variant of the serine cycle as follows: oxalyl-CoA reduction to glyoxylate and conversion to glycine and its condensation with methylene-tetrahydrofolate derived from formate, resulting in the formation of C3 units. The recently discovered ethylmalonyl-CoA pathway operates during growth on oxalate but is nevertheless dispensable, indicating that oxalyl-CoA reductase is sufficient to provide the glyoxylate required for biosynthesis. Analysis of an oxalyl-CoA synthetase- and oxalyl-CoA-reductase-deficient double mutant revealed an alternative, although less efficient, strategy for oxalate assimilation via one-carbon intermediates. The alternative process consists of formate assimilation via the tetrahydrofolate pathway to fuel the serine cycle, and the ethylmalonyl-CoA pathway is used for glyoxylate regeneration. Our results support the notion that M. extorquens AM1 has a plastic central metabolism featuring multiple assimilation routes for C1 and C2 substrates, which may contribute to the rapid adaptation of this organism to new substrates and the eventual coconsumption of substrates under environmental conditions.

Rhodobacter sphaeroides uses a reductive route via propionyl coenzyme A to assimilate 3-hydroxypropionate.

3-Hydroxypropionate is a product or intermediate of the carbon metabolism of organisms from all three domains of life. However, little is known about how carbon derived from 3-hydroxypropionate is assimilated by organisms that can utilize this C(3) compound as a carbon source. This work uses the model bacterium Rhodobacter sphaeroides to begin to elucidate how 3-hydroxypropionate can be incorporated into cell constituents. To this end, a quantitative assay for 3-hydroxypropionate was developed by using recombinant propionyl coenzyme A (propionyl-CoA) synthase from Chloroflexus aurantiacus. Using this assay, we demonstrate that R. sphaeroides can utilize 3-hydroxypropionate as the sole carbon source and energy source. We establish that acetyl-CoA is not the exclusive entry point for 3-hydroxypropionate into the central carbon metabolism and that the reductive conversion of 3-hydroxypropionate to propionyl-CoA is a necessary route for the assimilation of this molecule by R. sphaeroides. Our conclusion is based on the following findings: (i) crotonyl-CoA carboxylase/reductase, a key enzyme of the ethylmalonyl-CoA pathway for acetyl-CoA assimilation, was not essential for growth with 3-hydroxypropionate, as demonstrated by mutant analyses and enzyme activity measurements; (ii) the reductive conversion of 3-hydroxypropionate or acrylate to propionyl-CoA was detected in cell extracts of R. sphaeroides grown with 3-hydroxypropionate, and both activities were upregulated compared to the activities of succinate-grown cells; and (iii) the inactivation of acuI, encoding a candidate acrylyl-CoA reductase, resulted in a 3-hydroxypropionate-negative growth phenotype.

Comparative analysis of the complete genome sequence of the plant growth-promoting bacterium Bacillus amyloliquefaciens FZB42.

Bacillus amyloliquefaciens FZB42 is a Gram-positive, plant-associated bacterium, which stimulates plant growth and produces secondary metabolites that suppress soil-borne plant pathogens. Its 3,918-kb genome, containing an estimated 3,693 protein-coding sequences, lacks extended phage insertions, which occur ubiquitously in the closely related Bacillus subtilis 168 genome. The B. amyloliquefaciens FZB42 genome reveals an unexpected potential to produce secondary metabolites, including the polyketides bacillaene and difficidin. More than 8.5% of the genome is devoted to synthesizing antibiotics and siderophores by pathways not involving ribosomes. Besides five gene clusters, known from B. subtilis to mediate nonribosomal synthesis of secondary metabolites, we identified four giant gene clusters absent in B. subtilis 168. The pks2 gene cluster encodes the components to synthesize the macrolactin core skeleton.

Synthesis and evaluation of a netropsin-proximicin-hybrid library for DNA binding and cytotoxicity.

The proximicins A-C (1-3) are novel naturally occurring gamma-peptides with a hitherto unknown 2,4-disubstituted furan amino acid as a core structure. They show a moderate cytotoxic activity and induce upregulation of cell cycle regulating proteins (p53 and p21) and lead to cell cycle arrest in G0/G1-phase. Hybrid molecules combining structural motifs of the proximicins and of netropsin (4), a structurally related natural product, seem to have similar effects. Herein we describe the synthesis of a netropsin-proximicin-hybrid library and its evaluation regarding cytotoxicity and minor groove binding activity.

Lipocarbazoles, secondary metabolites from Tsukamurella pseudospumae Acta 1857 with antioxidative activity.

A family of new secondary metabolites with a carbazole moiety and an alkyl side chain was isolated from Tsukamurella pseudospumae strain Acta 1857. They were named lipocarbazoles in accordance with their chemical structures, which were determined by mass spectrometry and NMR spectroscopy. Lipocarbazoles are free radical scavengers showing antioxidative activity.

Nataxazole, a new benzoxazole derivative with antitumor activity produced by Streptomyces sp. Tü 6176.

The new benzoxazole derivative nataxazole was isolated from Streptomyces sp. (strain Tü 6176). Nataxazole is related in structure to the potent antitumor compounds UK-1 and AJI9561 and showed similar strong growth inhibitory activity against various human tumor cell lines.

Proximicin A, B and C, novel aminofuran antibiotic and anticancer compounds isolated from marine strains of the actinomycete Verrucosispora.

A family of three novel aminofuran antibiotics named as proximicins was isolated from the marine Verrucosispora strain MG-37. Proximicin A was detected in parallel in the marine abyssomicin producer "Verrucosispora maris" AB-18-032. The characteristic structural element of proximicins is 4-amino-furan-2-carboxylic acid, a hitherto unknown gamma-amino acid. Proximicins show a weak antibacterial activity but a strong cytostatic effect to various human tumor cell lines.

Bendigoles A approximately C, new steroids from Gordonia australis Acta 2299.

Bendigoles A approximately C are the first secondary metabolites to be isolated from a member of the actinomycete genus Gordonia. They were detected in a culture filtrate extract of Gordonia australis Acta 2299 by HPLC-diode array analysis and characterized as new steroids by mass spectrometry and NMR experiments. Bendigole C show binding affinity to the human progesterone and A approximately C to androgen receptor but are inactive at mineralocorticoid and estrogen receptors. In in vitro transactivation studies bendigoles A and C showed moderate and weak androgenic activities.

Elloxazinones A and B, New Aminophenoxazinones from Streptomyces griseus Acta 2871.

Two new aminophenoxazinone compounds with antitumor activity, elloxazinone A and B, were isolated from the culture filtrate of Streptomyces griseus Acta 2871. Their chemical structures were determined by mass spectrometry, NMR spectroscopy and X-ray analysis. Elloxazinones A and B showed a moderate inhibition of the proliferation of human cells from gastric adenocarcinoma in vitro but a strong inhibition of hepatocellular carcinoma cells whereas elloxazinone B strongly inhibited the proliferation of human breast carcinoma cells.

Structure elucidation of auxofuran, a metabolite involved in stimulating growth of fly agaric, produced by the mycorrhiza helper bacterium Streptomyces AcH 505.

Mycorrhiza helper bacterium Streptomyces strain AcH 505 stimulates ectomycorrhiza formation between spruce and fly agaric by supporting fungal growth whereas growth of pathogenic fungi is suppressed. A fungal growth promoting substance was isolated and the chemical structure elucidated by mass spectrometry and NMR spectroscopy. The absolute configuration of the novel fungal growth promoting compound auxofuran (1) was deduced from NMR data with the help of Mosher esters.

The structures of fluostatins C, D and E, novel members of the fluostatin family.

Three new fluostatin antibiotics have been isolated from the culture filtrate of Streptomyces strain Acta 1383. The chemical structures of these compounds were determined by mass spectrometry and NMR spectroscopy. The relative configuration has been determined by X-ray crystal structure analysis and the absolute configuration was deduced from NMR data with the help of Helmchen esters. These compounds represent the first reported epoxide fluostatins (1, 2) and underline previously found analogies to the group of kinamycin antibiotics.

Fluostatins C-E, novel members of the fluostatin family produced by Streptomyces strain Acta 1383.

Three new members of the fluostatin family, fluostatins C-E, were discovered in a culture filtrate extract of strain Acta 1383 during an HPLC screening program. The producing strain belongs to the genus Streptomyces and is closely related to type strains classified in the Streptomyces lavendulae 16S rRNA subclade. Fluostatins are named by their characteristic fluorenone chromophore. Fluostatin C shows moderate activity against selected human tumor cell lines.

A new kaempferol diglycoside from Datura suaveolens Humb. & Bonpl. ex. Willd.

A new flavonol glycoside, kaempferol 3-O-alpha-L-arabinopyranosyl-7-O-beta-D-glucopyranoside (1), has been isolated from methanol extract of leaves of Datura suaveolens (Solanaceae), along with six other known compounds, which include kaempferol 3-O-alpha-L-arabinopyranoside (2), 3-phenyl lactic acid, 3-(3-indolyl) lactic acid, and its methyl ester, physalindicanol A and physalindicanol B. The structural elucidation of 1 and characterization of the known compounds are based on detailed spectral analysis (ESI-FTICR-MS and 2D-NMR). This is the first report of isolation of these compounds from this plant.

Differential Diagnosis of Autoimmune Pancreatitis From Pancreatic Cancer by Analysis of Serum Gelatinase Levels.

OBJECTIVES: The aim of this study was to analyze serum gelatinases as part of the clinical strategy for the preoperative differentiation between autoimmune pancreatitis (AIP) and pancreatic ductal adenocarcinoma (PDAC). The finding of differential markers will prevent unnecessary surgical resection and allow optimal treatment of these diseases. METHODS: Quantitative gelatin zymography was applied to analyze all individual gelatinase forms in serum and to define proteinase alterations associated with AIP and PDAC. For this purpose, sera of 130 patients, being 29 with AIP, 33 with chronic pancreatitis, 32 with PDAC, and 36 healthy controls, were first assayed for gelatinase levels by quantitative zymography before further validation by the analysis with commercial sandwich enzyme linked immunosorbent assays. RESULTS: Serum profiling data obtained by zymography analysis revealed that gelatinase B/matrix metalloproteinase 9 (MMP-9), the neutrophil gelatinase B-associated lipocalin/MMP-9 complex, and gelatinase A/MMP-2 levels were significantly increased in patients with AIP. These proteins are promising markers to discriminate between AIP and PDAC. The best composite parameter, being the ratio of total MMP-9 over MMP-2 levels, can predict 93% of the AIP and 75% of the PDAC correctly. With enzyme linked immunosorbent assay, we confirmed the zymography results. CONCLUSIONS: Differential gelatinase serum profiles as AIP markers, together with other clinical tests, help to assure the diagnosis of PDAC or AIP.

Identification of Novel Serum Autoantibodies for Differential Diagnosis of Autoimmune Pancreatitis and Pancreatic Ductal Adenocarcinoma.

OBJECTIVES: The lack of specific biochemical markers is a major drawback for the diagnosis of autoimmune pancreatitis (AIP). The aims were to characterize the autoantibody profiles in AIP and pancreatic ductal adenocarcinoma (PDAC) and to identify circulating autoantibodies that could be diagnostic markers differentiating PDAC and the AIP subtypes. METHODS: Tissue lysates obtained from the resected pancreas of patients with AIP and patients with PDAC were separated by 2-dimensional polyacrylamide gel electrophoresis subsequently immunoblotted with autologous sera. The immunoreactive spots were subjected to nanoscale liquid chromatography-electrospray ionization tandem mass spectrometry to identify serum autoantibodies to tissue-derived autoantigens associated with AIP and PDAC. Autoantibody concentrations for selected autoantigens were assessed by enzyme-linked immunosorbent assays. RESULTS: A total of 115 immunoreactive spots were identified by 2-dimensional polyacrylamide gel electrophoresis/immunobloting. Nanoscale liquid chromatography-electrospray ionization tandem mass spectrometry-based analysis revealed 68 autoantigens in AIP, 26 in PDAC, and 21 present in both diseases. Assessment of 13 selected AIP autoantibody serum levels revealed that 7 of them had significantly higher titers in AIP versus PDAC. IgG-directed against transaldolase could significantly differentiate between the 2 AIP subtypes. CONCLUSIONS: The novel panel of AIP autoantibodies is promising to supplement the predictive tests for AIP of the currently known autoantigens and represent a basis for a combined blood test to differentiate AIP from PDAC in the future.