TY - JOUR A1 - Wittmar, J. A1 - Meyer, Susann A1 - Sieling, T. A1 - Kunte, Hans-Jörg A1 - Smiatek, Jens A1 - Brand, Izabella T1 - What Does Ectoine Do to DNA? A Molecular-Scale Picture of Compatible Solute−Biopolymer Interactions JF - The Journal of Physical Chemistry N2 - Compatible solutes are accumulated in the cytoplasm of halophilic microorganisms. These molecules enable their survival in a high salinity environment. Ectoine is such a compatible solute. It is a zwitterionic molecule which strongly interacts with surrounding water molecules and changes the dynamics of the local hydration shell. Ectoine interacts with biomolecules such as lipids, proteins and DNA. The molecular interaction between ectoine and biomolecules in particular the interaction between ectoine and DNA is far from being understood. In this paper we describe molecular aspects of the interaction between ectoine and double stranded DNA(dsDNA). Two 20 base pairs long dsDNA fragments were immobilized on a Gold surface via a thiol-tether. The interaction between the dsDNA monolayers with diluted and concentrated ectoine solutions was examined by means of X-ray photoelectron and polarization modulation infrared reflection absorption spectroscopies (PM IRRAS). Experimental results indicate that the ability of ectoine to bind water reduces the strength of hydrogen bonds formed to the ribose-phosphate backbone in the dsDNA. In diluted (0.1 M) ectoine solution, DNA interacts predominantly with water molecules. The sugar-phosphate backbone is involved in the formation of strong hydrogen bonds to water, which with elapsing time leads to a reorientation of the planes of nucleic acid bases. This reorientation destabilizes the hydrogen bonds strength between the bases and leads to a partial dehybridizaiton of the dsDNA. In concentrated ectoine solution (2.5 M), almost all water molecules interact with ectoine. Under this condition ectoine is able to interact directly with DNA. Density functional theory (DFT) calculations demonstrate that the direct interaction involves the nitrogen atoms in ectoine and phosphate groups in the DNA molecule. The results of the quantum chemical calculations Show that rearrangements in the ribose-phosphate backbone, caused by a direct interaction with ectoine, facilitates contacts between O atom in the phosphate group and H atoms in a nucleic acid base. In the PM IRRA spectra, an increase in the number of the IR absorption modes in the base pair frequency region proves that the hydrogen bonds between bases become weaker. Thus, a sequence of reorientations caused by interaction with ectoine leads to a breakdown of hydrogen bonds between bases in the double helix. KW - Compatible solute KW - Ectoine KW - DNA KW - Self-assembled monolayer KW - IR spectroscopy KW - XPS PY - 2020 DO - https://doi.org/10.1021/acs.jpcb.0c05273 VL - 124 IS - 37 SP - 7999 EP - 8011 PB - ACS Publicatios AN - OPUS4-51182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - He, Shulin A1 - Johnston, P. R. A1 - Kuropka, B. A1 - Lokatis, S. A1 - Weise, C. A1 - Plarre, Rüdiger A1 - Kunte, Hans-Jörg A1 - McMahon, Dino Peter T1 - Termite soldiers contribute to social immunity by synthesizing potent oral secretions JF - Insect Molecular Biology N2 - The importance of soldiers to termite Society defence has long been recognized, but the contribution of soldiers to other societal functions, such as colony immunity, is less well understood. We explore this issue by examining the role of soldiers in protecting nestmates against pathogen infection. Even though they are unable to engage in grooming behaviour, we find that the presence of soldiers of the Darwin termite, Mastotermes darwiniensis, significantly improves the survival of nestmates following entomopathogenic infection. We also show that the copious exocrine oral secretions produced by Darwin termite soldiers contain a high concentration of Proteins involved in digestion, chemical biosynthesis, and immunity. The oral secretions produced by soldiers are sufficient to protect nestmates against infection, and they have potent inhibitory activity against a broad spectrum of microbes. Our findings support the view that soldiers may play an important role in colony immunity, and broaden our understanding of the possible function of soldiers during the origin of soldier-first societies. KW - External KW - Social KW - Immunity KW - Soldier KW - Antimicrobial KW - Proteome PY - 2018 DO - https://doi.org/10.1111/imb.12499 SN - 1365-2583 SN - 0962-1075 VL - 27 IS - 5 SP - 564 EP - 576 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-45726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hobmeier, K. A1 - Oppermann, M. A1 - Stasinski, N. A1 - Kremling, A. A1 - Pflüger-Grau, K. A1 - Kunte, Hans-Jörg A1 - Marin Sanguino, A. T1 - Metabolic engineering of Halomonas elongata: Ectoine secretion is increased by demand and supply driven approaches JF - Frontiers in Microbiology N2 - The application of naturally-derived biomolecules in everyday products, replacing conventional synthetic manufacturing, is an ever-increasing market. An example of this is the compatible solute ectoine, which is contained in a plethora of treatment formulations for medicinal products and cosmetics. As of today, ectoine is produced in a scale of tons each year by the natural producer Halomonas elongata. In this work, we explore two complementary approaches to obtain genetically improved producer strains for ectoine production. We explore the effect of increased precursor supply (oxaloacetate) on ectoine production, as well as an implementation of increased ectoine demand through the overexpression of a transporter. Both approaches were implemented on an already genetically modified ectoine-excreting strain H. elongata KB2.13 (ΔteaABC ΔdoeA) and both led to new strains with higher ectoine excretion. The supply driven approach led to a 45% increase in ectoine titers in two different strains. This increase was attributed to the removal of phosphoenolpyruvate carboxykinase (PEPCK), which allowed the conversion of 17.9% of the glucose substrate to ectoine. For the demand driven approach, we investigated the potential of the TeaBC transmembrane proteins from the ectoine-specific Tripartite ATP-Independent Periplasmic (TRAP) transporter as export channels to improve ectoine excretion. In the absence of the substrate-binding protein TeaA, an overexpression of both subunits TeaBC facilitated a three-fold increased excretion rate of ectoine. Individually, the large subunit TeaC showed an approximately five times higher extracellular ectoine concentration per dry weight compared to TeaBC shortly after its expression was induced. However, the detrimental effect on growth and ectoine titer at the end of the process hints toward a negative impact of TeaC overexpression on membrane integrity and possibly leads to cell lysis. By using either strategy, the ectoine synthesis and excretion in H. elongata could be boosted drastically. The inherent complementary nature of these approaches point at a coordinated implementation of both as a promising strategy for future projects in Metabolic Engineering. Moreover, a wide variation of intracelllular ectoine levels was observed between the strains, which points at a major disruption of mechanisms responsible for ectoine regulation in strain KB2.13. KW - Osmoadaptation KW - Metabolic engineering PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555644 DO - https://doi.org/10.3389/fmicb.2022.968983 SN - 1664-302X VL - 13 SP - 1 EP - 13 PB - Frontiers Media CY - Lausanne AN - OPUS4-55564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, A1 - Zheng, A1 - Zhang, A1 - Lu, A1 - Wang, A1 - Kunte, Hans-Jörg A1 - Sand, W. T1 - Long Term Temperature and Humidity Evolution Forecast in Near Field of Nuclear Waste Container JF - Zhuangbei-huanjing-gongcheng = Equipment environmental engineering N2 - The paper aims to simulate the corrosion environment of nuclear waste containers at different geological disposal periods to obtain temperature and humidity information at the interface between the container and the surrounding environment. The simulated data and calculation results of long term temperature evolution at the surface of nuclear waste (HLW) containers from some typical nuclear countries about the safety disposition were reviewed. Combining different burial patterns, this paper speculated the long term temperature evolution rule for China. According to the study about saturation variation of buffer/backfill material at home and abroad, the humidity evolution of bentonite at the surface of HLW containers was specu- lated. The study showed that the temperature of the container surface increased rapidly at the beginning, and gradually decreased after the climax. For safety reasons, the maximum temperature was designed below 100°C. The saturation of bentonite was af- fected by the mutual influences of the heat released by nuclear waste decay and the infiltration of groundwater. It was dominated by the released heat in the early stage, and later was influenced greatly by the infiltration of groundwater. It is generally believed that the water content at the surface of the container will increase obviously in about 3 years, and will be saturated in about 10 years. The prediction of long-term temperature and humidity evolution will lay a foundation for study of corrosion evolution of nuclear waste containers in China. KW - Corrosion evolution KW - Nuclear waste KW - Disposal repository KW - Temperature and humidity PY - 2018 SN - 1672-9242 VL - 15 IS - 10 SP - 109 EP - 113 PB - Zhongguo Bingqi Gongye di-wujiu Yanjiusuo CY - Chongqing AN - OPUS4-46953 LA - zho AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Q. A1 - Zheng, M. A1 - Huang, Y. A1 - Kunte, Hans-Jörg A1 - Wang, X. A1 - Liu, Y. A1 - Zheng, C. T1 - Long term corrosion estimation of carbon steel, titanium and its alloy in backfill material of compacted bentonite for nuclear waste repository JF - Scientific reports N2 - The container of high-level radioactive waste (HLRW) being in deep geological disposal, the backfill material is needed to serve as the second defense for HLRW and the highly compacted bentonite is generally selected. As the time goes, the underground water will infiltrate the backfill, causing the corrosion of materials for the building of containers in the formed electrolyte. Carbon steel, titanium and its alloy are the potential candidate materials for the fabrication of HLRW containers. The current investigation aims at assessing the safety of HLRW container in deep geological disposal for hundreds of thousands of years and facilitating the material selection for future Container fabrication by estimating their corrosion behavior in compacted bentonite with a series of moisture content at different temperatures through electrochemical methods including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements. The corrosion rates were estimated for a carbon steel, a pure titanium and a titanium alloy in compacted Gaomiaozi Bentonite infiltrated with simulated underground water in Beishan area of China over an expected disposal period up to 106 years respectively, showing that titanium and its alloy are more reliable materials for building HLRW containers than carbon steel. KW - Issues KW - Disposal KW - Performance KW - Moisture KW - Lifetime KW - Water KW - Model PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492413 DO - https://doi.org/10.1038/s41598-019-39751-9 SN - 2045-2322 VL - 9 SP - 3195 PB - Nature Publishing Group AN - OPUS4-49241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, Yong A1 - Huang, Yanliang A1 - Yang, D. A1 - Kunte, Hans-Jörg A1 - De Marco, R. A1 - Wang, X. T1 - Investigation of the calcareous deposits formation controlled by interfacial pH and its effect on the hydrogen entry into AISI 4135 steel in seawater JF - International Journal of Hydrogen Energy N2 - The influence of interfacial pH between AISI 4135 steel and seawater under different polarization potentials on the formation of calcareous deposits has been studied. An interfacial pH of 9.61 at −0.9 V vs. SCE using state of the art iridium oxide microelectrode was found to be the critical pH for the precipitation of magnesium hydroxide. Calcareous deposits with a double-layer structure comprising an inner-brucite layer and an outer-aragonite layer were found to form at potentials between −1.0 V and −1.2 V vs. SCE. Furthermore, the facilitation of hydrogen permeation into steel induced by the formation of calcareous deposits was verified using the Devanathan-Stachurski electrochemical test. The mechanism of calcareous deposits facilitates hydrogen permeation into steel is related to its inhibition on hydrogen recombination and escape processes. KW - Low alloy steel KW - Cathodic protection KW - Calcareous deposits KW - Hydrogen permeation PY - 2020 DO - https://doi.org/10.1016/j.ijhydene.2020.11.040 SN - 0360-3199 SP - 1 EP - 18 PB - Elsevier Ltd. AN - OPUS4-51730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oprzeska-Zingrebe, E. A. A1 - Meyer, Susann A1 - Roloff, Alexander A1 - Kunte, Hans-Jörg A1 - Smiatek, J. T1 - Influence of compatible solute ectoine on distinct DNA structures: thermodynamic insights into molecular binding mechanisms and destabilization effects JF - Phys.Chem.Chem.Phys. N2 - In nature, the cellular environment of DNA includes not only water and ions, but also other components and co-solutes, which can exert both stabilizing and destabilizing effects on particular oligonucleotide conformations. Among them, ectoine, known as an important osmoprotectant organic co-solute in a broad range of pharmaceutical products, turns out to be of particular relevance. In this article, we study the influence of ectoine on a short single-stranded DNA fragment and on double-stranded helical B-DNA in aqueous solution by means of atomistic molecular dynamics (MD) simulations in combination with molecular theories of solution. Our results demonstrate a conformation-dependent binding behavior of ectoine, which favors the unfolded state of DNA by a combination of electrostatic and dispersion interactions. In conjunction with the Kirkwood–Buff theory, we introduce a simple Framework to compute the influence of ectoine on the DNA melting temperature. Our findings reveal a significant linear decrease of the melting temperature with increasing ectoine concentration, which is found to be in qualitative agreement with results from denaturation experiments. The outcomes of our Computer simulations provide a detailed mechanistic rationale for the surprising destabilizing influence of ectoine on distinct DNA structures. KW - Ectoine KW - DNA KW - Thermodynamic KW - Melting temperature PY - 2018 DO - https://doi.org/10.1039/c8cp03543a SN - 1463-9076 SN - 1463-9084 VL - 20 IS - 40 SP - 25861 EP - 25874 PB - Royal Society of Chemistry AN - OPUS4-46327 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huang, Yanliang A1 - Liu, Xiangju A1 - Zhang, Qichao A1 - Xu, Yong A1 - Kunte, Hans-Jörg A1 - De Marco, Roland T1 - Hydrogen release from carbon steel in chloride solution under anodic polarization JF - International Journal of Hydrogen Energy N2 - The hydrogen permeation current increase was noticed for carbon steel in 0.5 mol/L NaCl solution under strong anodic potentials, which is contrary to the common understanding. Hydrogen permeation under cathodic potentials has been widely studied because of possible hydrogen embrittlement failures of high strength steels in seawater, but investigations of anodic polarization on hydrogen permeation are fairly rare, as the hydrogen evolution reaction shall be retarded. To corroborate the observed phenomenon, experiments were conducted using both as-received and vacuum-annealed sheet specimens. It was verified that the observed phenomena originated from the released hydrogen in traps by metal dissolution under anodic polarization. KW - Energy Engineering and Power Technology KW - Condensed Matter Physics KW - Fuel Technology KW - Renewable Energy, Sustainability and the Environment PY - 2020 DO - https://doi.org/10.1016/j.ijhydene.2019.11.218 SN - 1879-3487 VL - 45 IS - 4 SP - 3307 EP - 3315 PB - Elsevier BV CY - New York, NY AN - OPUS4-59322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Beate A1 - Pfeiffer, F. A1 - Dyall-Smith, M. A1 - Kunte, Hans-Jörg T1 - Genome Sequence of Pseudomonas veronii Strain G2, a Member of a Bacterial Consortium Capable of Polyethylene Degradation JF - Microbiology Ressource Announcements N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G2 was determined by PacBio sequencing. Using the TYGS server for taxonomic classification, strain G2 was assigned to the species Pseudomonas veronii. KW - Polyethylene KW - Next generation sequencing KW - Pseudomonas veronii PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548973 DO - https://doi.org/10.1128/mra.00365-22 SP - 1 EP - 2 PB - ASM AN - OPUS4-54897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Beate A1 - Pfeiffer, F. A1 - Dyall-Smith, M. A1 - Kunte, Hans-Jörg T1 - Genome Sequence of Micromonospora aurantiaca Strain G9, a Member of a Bacterial Consortium Capable of Polyethylene Degradation JF - Microbiology Ressource Announcements N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G9 was determined by PacBio sequencing. Using the TYGS server for taxonomic classification, strain G9 was assigned to the species Micromonospora aurantiaca. KW - Polyethylene KW - Micromonospora aurantiaca KW - Degradation KW - iChip PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547181 DO - https://doi.org/10.1128/mra.01148-21 SN - 2576-098X VL - 11 IS - 5 SP - 1 EP - 2 PB - American Society for Microbiology CY - Washington, DC AN - OPUS4-54718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -