Fakultät Naturwissenschaften

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Biologie, Ernährungs-wissenschaften und Lebensmittelwissenschaften sind die Schwerpunkte der Fakultät. Die Forschung befasst sich mit Schlüsselthemen der Life Sciences.

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3D chromatin maps of a brown alga reveal U/V sex chromosome spatial organization
(2024) Liu, Pengfei; Vigneau, Jeromine; Craig, Rory J.; Barrera-Redondo, Josué; Avdievich, Elena; Martinho, Claudia; Borg, Michael; Haas, Fabian B.; Liu, Chang; Coelho, Susana M.
Nuclear three dimensional (3D) folding of chromatin structure has been linked to gene expression regulation and correct developmental programs, but little is known about the 3D architecture of sex chromosomes within the nucleus, and how that impacts their role in sex determination. Here, we determine the sex-specific 3D organization of the model brown alga Ectocarpus chromosomes at 2 kb resolution, by mapping long-range chromosomal interactions using Hi-C coupled with Oxford Nanopore long reads. We report that Ectocarpus interphase chromatin exhibits a non-Rabl conformation, with strong contacts among telomeres and among centromeres, which feature centromere-specific LTR retrotransposons. The Ectocarpus chromosomes do not contain large local interactive domains that resemble TADs described in animals, but their 3D genome organization is largely shaped by post-translational modifications of histone proteins. We show that the sex determining region (SDR) within the U and V chromosomes are insulated and span the centromeres and we link sex-specific chromatin dynamics and gene expression levels to the 3D chromatin structure of the U and V chromosomes. Finally, we uncover the unique conformation of a large genomic region on chromosome 6 harboring an endogenous viral element, providing insights regarding the impact of a latent giant dsDNA virus on the host genome’s 3D chromosomal folding.
A sensitive bioassay to measure NOD1/2 ligands in human serum reveals differential postprandial NOD2 activation
(2025) Biber, Lucy; Schart, Nadine; Bosy-Westphal, Anja; Kufer, Thomas A.
Food intake is associated with the occurrence of components and metabolites from the gut microbiota in the bloodstream. Using a widely utilised cell-based assay to measure bacterial peptidoglycan via pattern-recognition receptor activation, we found that the performance of this assay is significantly influenced by the presence of other serum components. To address this challenge, an alternative luciferase-based reporter assay protocol was established to accurately measure NOD1 and NOD2 activation by serum samples with high sensitivity. Utilising postprandial human serum samples, we tested this assay and showed that the concentration of NOD2-activating ligands differed in the postprandial phase. Together, we provide a protocol to measure NOD1/2 activation by human serum samples and highlight a role for NOD2 in the postprandial response.
ACHEMA 2022: Innovationen und Trends in der Trocknungstechnik
(2023) Ruprecht, Nora Alina; Frank, Jennifer; Raiber, Tobias V.; Teichmann, Heike; Gschwind, Peter; Kohlus, Reinhard
In diesem Beitrag werden die Highlights der auf der ACHEMA 2022 ausgestellten Neuerungen zusammengefasst und es wird über die beobachteten Trends berichtet. Neben neuen Anlagen in einzelnen Trocknungsbereichen wurden die Schritte der Firmen in den Bereichen der Schwerpunktthemen Digitalisierung und Nachhaltigkeit näher betrachtet.
Acrocomia aculeata fruits from three regions in Costa Rica: An assessment of biometric parameters, oil content and oil fatty acid composition to evaluate industrial potential
(2020) Alfaro-Solís, Jose David; Montoya-Arroyo, Alexander; Jiménez, Víctor M.; Arnáez-Serrano, Elizabeth; Pérez, Jason; Vetter, Walter; Frank, Jan; Lewandowski, Iris
Due to increased global demand for vegetable oils, diversification of the supply chain with sustainable sources is necessary. Acrocomia aculeata has recently gained attention as a multi-purpose, sustainable crop for oil production. However, the information necessary for effective selection of promising varieties for agricultural production is lacking. The aim of this study was to assess variability in fruit morphology and oil composition of individual Acrocomia aculeata plants growing wild in different climatic regions of Costa Rica. Fruits at the same ripening stage were collected at three locations, and biometric features, oil content, fatty acid composition of oils from kernels and pulp, as well as fiber composition of husks were determined. Biometric parameters showed high variability among the regions assessed. Moreover, oil content and relative proportions of unsaturated fatty acids were higher at the most tropical location, whereas lauric acid content was lowest under these conditions, indicating a potential environmental effect on oil composition. Pulp oil content correlated positively with annual precipitation and relative humidity, but no clear relation to temperature was observed. The oil chemical composition was similar to that reported for Elaeis guineensis, suggesting that Acrocomia aculeata from Costa Rica may be a suitable alternative for industrial applications currently based on African palm oil. Analysis of husks as a coproduct revealed the possibility of obtaining materials with high lignin and low water and ash contents that could be used as a solid bioenergy source. In conclusion, Acrocomia aculeata oil is a promising alternative for industrial applications currently based on African palm oil and byproducts of its oil production could find additional use as a renewable energy source.
Activation of small molecules by readily accessible alkylborane‐based frustrated lewis pairs
(2025) Averdunk, Arthur; Wech, Felix; Becker, Jonathan; Gellrich, Urs
Herein, we report that sterically encumbered (thio)imidazolones react with simple aliphatic boranes, such as 9‐borabicyclo[3.3.1]nonane (H‐B‐9‐BBN) or dicyclohexylborane (HBCy2), at room temperature to form (thio)imidazolonate boranes,which function as intramolecular frustrated lewis pairs (FLPs). Although direct observation of hydrogen activation by these FLPs is not possible, alkene hydroboration occurs when they are reacted with styrene under hydrogen pressure, suggesting that hydrogen activation is kinetically feasible. In addition, these FLPs rapidly activate NH bonds, as demonstrated by the activation of ammonia and amines under mild conditions. They also cleave the CH bond of terminal alkynes. Density functional theory (DFT) calculations are used to investigate the thermodynamics and kinetics of hydrogen and ammonia activation by these FLPs.
Adaptation of Listeria monocytogenes to perturbation of c‐di‐AMP metabolism underpins its role in osmoadaptation and identifies a fosfomycin uptake system
(2022) Wang, Mengyi; Wamp, Sabrina; Gibhardt, Johannes; Holland, Gudrun; Schwedt, Inge; Schmidtke, Kai‐Uwe; Scheibner, Katrin; Halbedel, Sven; Commichau, Fabian M.
The human pathogen Listeria monocytogenes synthesizes and degrades c‐di‐AMP using the diadenylate cyclase CdaA and the phosphodiesterases PdeA and PgpH respectively. c‐di‐AMP is essential because it prevents the uncontrolled uptake of osmolytes. Here, we studied the phenotypes of cdaA, pdeA, pgpH and pdeA pgpH mutants with defects in c‐di‐AMP metabolism and characterized suppressor mutants restoring their growth defects. The characterization of the pdeA pgpH mutant revealed that the bacteria show growth defects in defined medium, a phenotype that is invariably suppressed by mutations in cdaA. The previously reported growth defect of the cdaA mutant in rich medium is suppressed by mutations that osmotically stabilize the c‐di‐AMP‐free strain. We also found that the cdaA mutant has an increased sensitivity against isoleucine. The isoleucine‐dependent growth inhibition of the cdaA mutant is suppressed by codY mutations that likely reduce the DNA‐binding activity of encoded CodY variants. Moreover, the characterization of the cdaA suppressor mutants revealed that the Opp oligopeptide transport system is involved in the uptake of the antibiotic fosfomycin. In conclusion, the suppressor analysis corroborates a key function of c‐di‐AMP in controlling osmolyte homeostasis in L. monocytogenes.
The added value of km-scale simulations to describe temperature over complex orography: the CORDEX FPS-Convection multi-model ensemble runs over the Alps
(2024) Soares, P. M. M.; Careto, J. A. M.; Cardoso, Rita M.; Goergen, Klaus; Katragkou, Eleni; Sobolowski, Stefan; Coppola, Erika; Ban, Nikolina; Belušić, Danijel; Berthou, Ségolène; Caillaud, Cécile; Dobler, Andreas; Hodnebrog, Øivind; Kartsios, Stergios; Lenderink, Geert; Lorenz, T.; Milovac, Josipa; Feldmann, Hendrik; Pichelli, Emanuela; Truhetz, Heimo; Demory, Marie Estelle; de Vries, Hylke; Warrach-Sagi, Kirsten; Keuler, Klaus; Raffa, Mario; Tölle, Merja; Sieck, Kevin; Bastin, Sophie
The increase in computational resources has enabled the emergence of multi-model ensembles of convection-permitting regional climate model (CPRCM) simulations at very high horizontal resolutions. An example is the CORDEX Flagship Pilot Study on “Convective phenomena at high resolution over Europe and the Mediterranean”, a set of kilometre-scale simulations over an extended Alpine domain. This first-of-its-kind multi-model ensemble, forced by the ERA-Interim reanalysis, can be considered a benchmark dataset. This study uses a recently proposed metric to determine the added value of all the available Flagship Pilot Study hindcast kilometre-scale simulations for maximum and minimum temperature. The analysis is performed using state-of-the-art gridded and station observations as ground truth. This approach directly assesses the added value between the high-resolution CPRCMs against their driving global simulations and coarser resolution RCM counterparts. Overall, models display some modest gains, but also considerable shortcomings are exhibited. In part, these deficiencies can be attributed to the assimilation of temperature observations into ERA-Interim. Although the gains for the use of kilometre-scale resolution for temperature are limited, the improvement of the spatial representation of local atmospheric circulations and land–atmosphere interactions can ultimately lead to gains, particularly in coastal areas.
The added value of simulated near-surface wind speed over the Alps from a km-scale multimodel ensemble
(2024) Molina, M. O.; Careto, J. M.; Gutiérrez, C.; Sánchez, E.; Goergen, K.; Sobolowski, S.; Coppola, E.; Pichelli, E.; Ban, N.; Belus̆ić, D.; Short, C.; Caillaud, C.; Dobler, A.; Hodnebrog, Ø.; Kartsios, S.; Lenderink, G.; de Vries, H.; Göktürk, O.; Milovac, Josipa; Feldmann, H.; Truhetz, H.; Demory, M. E.; Warrach-Sagi, Kirsten; Keuler, K.; Adinolfi, M.; Raffa, M.; Tölle, M.; Sieck, K.; Bastin, S.; Soares, P. M. M.
The advancement of computational resources has allowed researchers to run convection-permitting regional climate model (CPRCM) simulations. A pioneering effort promoting a multimodel ensemble of such simulations is the CORDEX Flagship Pilot Studies (FPS) on “Convective Phenomena over Europe and the Mediterranean” over an extended Alps region. In this study, the Distribution Added Value metric is used to determine the improvement of the representation of all available FPS hindcast simulations for the daily mean near-surface wind speed. The analysis is performed on normalized empirical probability distributions and considers station observation data as the reference. The use of a normalized metric allows for spatial comparison among the different regions (coast and inland), altitudes and seasons. This approach permits a direct assessment of the added value between the CPRCM simulations against their global driving reanalysis (ERA-Interim) and respective coarser resolution regional model counterparts. In general, the results show that CPRCMs add value to their global driving reanalysis or forcing regional model, due to better-resolved topography or through better representation of ocean-land contrasts. However, the nature and magnitude of the improvement in the wind speed representation vary depending on the model, the season, the altitude, or the region. Among seasons, the improvement is usually larger in summer than winter. CPRCMs generally display gains at low and medium-range altitudes. In addition, despite some shortcomings in comparison to ERA-Interim, which can be attributed to the assimilation of wind observations on the coast, the CPRCMs outperform the coarser regional climate models, both along the coast and inland.
Advancing 2D fluorescence online monitoring in microtiter plates by separating scattered light and fluorescence measurement, using a tunable emission monochromator
(2023) Berg, Christoph; Busch, Selma; Alawiyah, Muthia Dewi; Finger, Maurice; Ihling, Nina; Paquet-Durand, Olivier; Hitzmann, Bernd; Büchs, Jochen
Online fluorescence monitoring has become a key technology in modern bioprocess development, as it provides in‐depth process knowledge at comparably low costs. In particular, the technology is widely established for high‐throughput microbioreactor cultivation systems, due to its noninvasive character. For microtiter plates, previously also multi‐wavelength 2D fluorescence monitoring was developed. To overcome an observed limitation of fluorescence sensitivity, this study presents a modified spectroscopic setup, including a tunable emission monochromator. The new optical component enables the separation of the scattered and fluorescent light measurements, which allows for the adjustment of integration times of the charge‐coupled device detector. The resulting increased fluorescence sensitivity positively affected the performance of principal component analysis for spectral data of Escherichia coli batch cultivation experiments with varying sorbitol concentration supplementation. In direct comparison with spectral data recorded at short integration times, more biologically consistent signal dynamics were calculated. Furthermore, during partial least square regression for E. coli cultivation experiments with varying glucose concentrations, improved modeling performance was observed. Especially, for the growth‐uncoupled acetate concentration, a considerable improvement of the root‐mean‐square error from 0.25 to 0.17 g/L was achieved. In conclusion, the modified setup represents another important step in advancing 2D fluorescence monitoring in microtiter plates.
Almond-like aroma formation of acid whey by Ischnoderma benzoinum fermentation: potential application in novel beverage development
(2025) Hannemann, Lea; Klauss, Raphaela; Gleissle, Anne; Heinrich, Patrick; Braunbeck, Thomas; Zhang, Yanyan
To address the sourish off-aroma of acid whey and enhance its upcycling, a new basidiomycete Ischnoderma benzoinum -mediated fermentation system was developed using pure acid whey as the sole substrate. A pleasant sweetish and marzipan-like odor was perceived after fermentation within 7 d at 24 °C in darkness, which was shaped from key contributors including 4-methoxybenzaldehyde (odor activity value (OAV) 878), 3-methylbutanal (OAV 511), 3,4-dimethoxybenzaldehyde (OAV 50), and benzaldehyde (OAV 28). The typical sweetish and almond-like odor persisted well after ultrahigh-temperature processing, though its intensity decreased slightly. Concurrently, the fermentation reduced lactose from 52 to 20 g/L but increased the contents of essential amino acids like threonine, leucine, and lysine. No significant cytotoxicity or genotoxicity differences were found between fermented and unfermented whey. Overall, the study highlights the capability of I. benzoinum fermentation to enhance the flavor of acid whey, offering a promising approach for creating nutritional and flavorful acid-whey-based products.
AMP-activated protein kinase (AMPK)-dependent regulation of renal transport
(2018) Glosse, Philipp; Föller, Michael
Analysis of acrylamide in vegetable chips after derivatization with 2-mercaptobenzoic acid by liquid chromatography–mass spectrometry
(2022) Oellig, Claudia; Gottstein, Eva; Granvogl, Michael
Since many years, acrylamide (AA) is a well-known toxicologically relevant processing contaminant (“food-borne toxicant”). However, only during the recent years, high levels of acrylamide have been reported in vegetable chips. In the present study, AA was quantitated via a modified derivatization procedure with 2-mercaptobenzoic acid based on stable isotope dilution analysis and liquid chromatography–mass spectrometry. Extraction with a modified QuEChERS (quick, easy, cheap, efficient, rugged, safe) method, defatting with n -hexane, and a solid phase extraction clean-up with strong cation-exchange material were performed prior to the derivatization step. Limits of detection and quantitation (LoD and LoQ) were 12 and 41 µg of AA/kg of vegetable chips (estimated via signal-to-noise ratios of 3:1 and 10:1, respectively), and thus below the LoQ of 50 µg/kg requested by the European Food Safety Authority. Recovery rates between 92 and 101% at four spiking levels with a good precision expressed as a relative standard deviation < 7% were determined. With this method at hand, a survey of the current AA amounts in 38 vegetable chips from the worldwide market was performed, showing a remarkable variability between the different vegetables, but also between different products of the same vegetable. Thereby, the AA amounts ranged between 77.3 and 3090 µg/kg, with an average of 954 µg/kg which was distinctly higher in comparison to commercially available potato chips also analyzed in the present study (12 samples, range: 117–832 µg/kg, average: 449 µg/kg). While for sweet potato and parsnip relatively low AA amounts were found, beetroot and carrot showed rather high contents.
Analysis of highly polar anionic pesticides in food of plant and animal origin by ion chromatography and tandem mass spectrometry with emphasis on addressing adverse effects caused by matrix co-extractives
(2024) Schäfer, Ann-Kathrin; Vetter, Walter; Anastassiades, Michelangelo
Residues of various highly polar pesticides and their metabolites are commonly found in numerous food products. Some of these compounds, such as glyphosate, are not only used in large amounts in agriculture, but are also controversially discussed in public. Here, we present a method, employing ion chromatography (IC) coupled to tandem mass spectrometry (IC-MS/MS), for the analyses of glyphosate, aminomethyl phosphonic acid (AMPA), N -acetyl-glyphosate (NAGly), fosetyl, and 10 further highly polar pesticides and metabolites in various plant and animal matrices following a minimal sample preparation by means of the QuPPe method. Thorough investigations showed that an AS19 column enabled the analysis of all 14 compounds within 30 min. The best sensitivity could be obtained with the make-up solvent acetonitrile being admixed to the mobile phase at a 1:2 flow rate ratio. Matrix effects were thoroughly studied in terms of ion suppression and retention time shifts. Conductivity detection was used to monitor elution profiles of matrix co-extractives in comparison with matrix effect profiles obtained by continuous post-column infusion of a mix with 13 highly polar pesticides and metabolites. These tests indicated that a fivefold dilution of QuPPe extracts was suitable for the routine analysis of samples for MRL-conformity, as it considerably reduced matrix effects maintaining sufficient sensitivity and high recovery rates in eight different commodities. The suitability of the final method for its application in routine analysis was verified by the analysis of >130 samples containing incurred residues where the results were compared with two existing LC-MS/MS methods.
Analysis of mono-, di-, triacylglycerols, and fatty acids in food emulsifiers by high-performance liquid chromatography–mass spectrometry
(2021) Schick, Dinah; Link, Katharina; Schwack, Wolfgang; Granvogl, Michael; Oellig, Claudia
Mono- and diacylglycerols (MG/DG) of fatty acids (FA), known as emulsifiers of the type E 471, are food additives used to adjust techno-functional properties of various foodstuffs. These emulsifiers, however, are not defined single compounds but comprise, in addition to MG and DG, other constituents such as FA, triacylglycerols (TG), and glycerol. Although the emulsifiers’ compositions affect techno-functional properties of the food, knowledge of the composition is scarcely available, and the emulsifiers and their dosage are generally chosen empirically. Thus, a simple and rather inexpensive method for the simultaneous determination of FA, 1-MG, 2-MG, 1,2-DG, 1,3-DG, and TG by high-performance liquid chromatography–mass spectrometry including a straightforward quantitation strategy has been developed. Reversed-phase chromatography with gradient elution offered adequate separation of 29 considered analytes within 21 peaks, while mass-selective detection provided their unequivocal identification. The quantitation strategy based on calibration just with the C16:0 representatives of each lipid class and a corresponding response factor system has proven to provide reliable results. The determined concentrations of different mixtures comprising varying compositions and concentrations of C16:0, C18:0, and C18:1 components of each lipid class deviated < 20% (n = 351) from the respective target concentrations. Limits of decision were determined to 0.3–0.8 mg/L and limits of quantitation to 0.8–1.7 mg/L, expressed as C16:0 representatives. Application of the method to various E 471 emulsifiers provided detailed data on their chemical compositions, and calculated FA compositions matched very well those determined by common methods such as gas chromatography with flame ionization detection.
Analysis of protein-network formation of different vegetable proteins during emulsification to produce solid fat substitutes
(2021) Baune, Marie-Christin; Schroeder, Sarah; Witte, Franziska; Heinz, Volker; Bindrich, Ute; Weiss, Jochen; Terjung, Nino
Plant-based emulsion gels can be used as solid animal fat substitutes for vegan sausages. For this reason, commercially available protein isolates with different amino acid profiles from pea, soy and potato (Pea-1, Pea-2, Soy, Potato) have been tested for their ability to form shape stable emulsions gels at neutral pH and upon heating to 72 °C. In order to obtain emulsion gels that are as solid as possible, the protein concentrations in the continuous phase (CPC, 8.0–11.5% (w/w)) and the oil mass fractions (65–80%) were varied. For leguminous proteins, a positive correlation of both parameters on emulsion rigidity was shown, indicating that both, interfacial and protein–protein interactions, are involved in structure reinforcement. Firmness increased with increasing content in cysteine (Pea-1 < Pea-2 < Soy) and the interactions were of electrostatic, hydrophobic and hydrophilic nature. Potato emulsion rigidity was independent of CPC and oil content. The emulsions showed a much higher degree in crosslinking, and very low charge density. Temperature-sweep analysis and CLSM revealed that Potato protein gelled as consequence to low temperature stability. Hence, the structure reinforcement in Potato emulsions mainly contributed to the protein network, with 70% oil and CPC 11.5% forming a hybrid gel with highest firmness. However, gelling of Potato protein also resulted in interfacial adsorption of protein aggregates and reduced interfacial stability with increasing CPC. This was demonstrated in the amount of extractable fat which was 2.0 and 0.6% for Pea-1 and 2 emulsions, 6.4% for Soy and 34.4% of total fat for Potato emulsions.
Analysis of secondary inorganic aerosols over the greater Athens area using the EPISODE–CityChem source dispersion and photochemistry model
(2024) Myriokefalitakis, Stelios; Karl, Matthias; Weiss, Kim A.; Karagiannis, Dimitris; Athanasopoulou, Eleni; Kakouri, Anastasia; Bougiatioti, Aikaterini; Liakakou, Eleni; Stavroulas, Iasonas; Papangelis, Georgios; Grivas, Georgios; Paraskevopoulou, Despina; Speyer, Orestis; Mihalopoulos, Nikolaos; Gerasopoulos, Evangelos
Secondary inorganic aerosols (SIAs) are major components of fine particulate matter (PM 2.5), having substantial implications for climate and air quality in an urban environment. In this study, a state-of-the-art thermodynamic model has been coupled to the source dispersion and photochemistry city-scale chemistry transport model EPISODE–CityChem, which is able to simulate pollutants at a horizontal resolution of 100m×100m, to determine the equilibrium between the inorganic gas and aerosol phases over the greater Athens area, Greece, for the year 2019. In agreement with in situ observations, sulfate ( SO42-) is calculated to have the highest annual mean surface concentration (2.15  ± 0.88  µgm-3) among SIAs in the model domain, followed by ammonium ( NH4+; 0.58  ± 0.14  µgm-3) and fine nitrate ( NO3-; 0.24  ± 0.22  µgm-3). Simulations denote that NO3-formation strongly depends on the local nitrogen oxide emissions, along with the ambient temperature, the relative humidity, and the photochemical activity. Additionally, we show that anthropogenic combustion sources may have an important impact on the NO3-formation in an urban area. During the cold period, the combined effect of decreased temperature in the presence of non-sea-salt potassium favors the partitioning of HNO3in the aerosol phase in the model, raising the NO3-formation in the area. Overall, this work highlights the significance of atmospheric composition and the local meteorological conditions for the equilibrium distribution of nitrogen-containing semi-volatile compounds and the acidity of inorganic aerosols, especially in urban areas where atmospheric trace elements from natural and anthropogenic sources coexist.
Anemia among Syrian refugee children aged 6 to 23 months living in Greater Beirut, Lebanon, including the Voices of Mothers’ and Local Healthcare Staff: A mixed-methods study
(2023) Jeremias, Theresa; Abou-Rizk, Joana; Burgard, Leonie; Entenmann, Isa; Nasreddine, Lara; Jomaa, Lamis; Hwalla, Nahla; Frank, Jan; Scherbaum, Veronika
Globally, the prevalence of anemia among children during the period of complementary feeding is high. A cross-sectional, mixed-methods study was conducted to examine the main determinants of anemia among Syrian refugee children aged 6 to 23 months (n = 215) and to illuminate the knowledge, attitudes and perceptions of their mothers and Lebanese healthcare staff on its causes and available treatment options. 42% of the children and 20% of their mothers were anemic. Determinants of child anemia were the mother having anemia or not knowing that fish/seafood is a source of iron; the child having been acutely ill the last two weeks or receiving cow’s milk, but not consuming iron-rich infant formula, added fats/oils, or fruits in the previous 24 hours. Several Syrian mothers knew some causes of anemia and named dizziness as a leading symptom but did not mention flesh foods as a key source of heme iron. They reported financial constraints in accessing iron-rich foods and supplements. Lebanese doctors largely gave appropriate dietary advice and prescribed iron supplements as treatment. Multisectoral interventions are needed that combine medical and financial support with nutrition counseling for mothers to reduce the high burden of anemia among young children living in a multiple crises situation.
Animal‐free setup of a 3D mature adipocyte‐macrophage co‐culture to induce inflammation in vitro
(2025) Nowakowski, Sophia; Nellinger, Svenja; Albrecht, Franziska Brigitte; Kluger, Petra Juliane
Adipose tissue inflammation plays a central role in the pathogenesis of metabolic disorders. It is closely associated with immune cell infiltration, particularly macrophages, and the release of pro‐inflammatory cytokines. Reliable in vitro test systems that mimic the inflamed environment while being free of animal‐derived components are essential to explore new treatments for obesity‐related diseases. This study aims to develop a straightforward, animal‐free adipocyte‐macrophage co‐culture for investigating adipose tissue inflammation. Therefore, the human monocytic cell lines Mono Mac (MM6) and THP‐1 are co‐cultured with human primary mature adipocytes (ACs) encapsulated in gellan gum (GG) within a defined environment. Both monocytic cell lines are effectively activated by phorbol 12‐myristate 13‐acetate (PMA) and lipopolysaccharide (LPS) in the defined medium, exhibiting distinct cytokine profiles. A comparison between collagen and GG demonstrates that GG is a suitable animal‐free matrix material for ACs. PMA+LPS successfully activates the 3D adipocyte‐macrophage co‐culture to an inflammatory state for 72 h in the developed defined medium. Viability and intracellular lipid content remain high, and the functionality of ACs (perilipin A) in untreated models remains intact. This inflamed adipocyte‐macrophage co‐culture is easy to assemble and set up in a defined environment, making it a potential test system for anti‐inflammatory treatment strategies.
Anoxic cell rupture of Prevotella bryantii by high-pressure homogenization protects the Na+-translocating NADH:quinone oxidoreductase from oxidative damage
(2020) Schleicher, Lena; Fritz, Günter; Seifert, Jana; Steuber, Julia
Respiratory NADH oxidation in the rumen bacterium Prevotella bryantii is catalyzed by the Na+-translocating NADH:quinone oxidoreductase (NQR). A method for cell disruption and membrane isolation of P. bryantii under anoxic conditions using the EmulisFlex-C3 homogenizer is described. We compared NQR activity and protein yield after oxic and anoxic cell disruption by the EmulsiFlex, by ultrasonication, and by glass beads treatment. With an overall membrane protein yield of 50 mg L–1 culture and a NADH oxidation activity of 0.8 µmol min−1 mg−1, the EmulsiFlex was the most efficient method. Anoxic preparation yielded fourfold higher NQR activity compared to oxic preparation. P. bryantii lacks genes coding for superoxide dismutases and cell extracts do not exhibit superoxide dismutase activity. We propose that inactivation of NQR during oxic cell rupture is caused by superoxide, which accumulates in P. bryantii extracts exposed to air. Anoxic cell rupture is indispensable for the preparation of redox-active proteins and enzymes such as NQR from P. bryantii.
Anpassung von Modellbakterien an das Jahrhundertherbizid Glyphosat
(2024) Schwedt, Inge; Commichau, Fabian M.
Investigations on the adaptation mechanisms of well-studied model bacteria to the once in-a-century herbicide glyphosate can reveal novel functional relationships between seemingly well-studied cellular processes.

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