TY - CONF A1 - Julseth, Mara Jean T1 - Chromosome evolution in Reticulitermes of europe - dynamics of chain formation N2 - Termites, the oldest eusocial insect group, display important divergent features compared to the eusocial Hymenoptera, including diploidy and an XY sex differentiation system. Termite males have frequently been shown to generate multivalent chromosome chains and rings during meiosis. This intriguing phenomenon could act on multiple evolutionary scales. Firstly, chain formation creates a higher probability of large-scale chromosomal translocations, which could play an important role in chromosome evolution across deep evolutionary time. Secondly, chains occurring in meiosis I should suppress recombination, leading to accumulation of genetic divergence in corresponding chromosomal regions, with potential consequences for speciation dynamics. Suppressed recombination may also represent a mechanism to maintain genetic heterozygosity, thereby theoretically mitigating against the negative effects of inbreeding. A high tolerance for inbreeding could have played a prominent role during the evolution of termite eusociality through its potential impact on inclusive fitness. Using newly sequenced near-chromosome-level reference genomes of native European Reticulitermes species, we will compare chromosomal translocations against other termite species as well as solitary relatives from Blattodea. Additionally, combining a large-scale population genomic data set with high resolution karyotypying across the southern European range, we aim to test the hypotheses that the occurrence and extent of chromosomal rings or chains i) are positively correlated with inbreeding, and ii) contribute to species divergence via the accumulation and fixation of genetic differences. In summary, this project seeks to identify the diverse roles that chain and ring chromosomes have played and continue to play in termite evolution. T2 - SPP Meeting Gevol CY - Frankfurt am Main, Germany DA - 30.09.2024 KW - Termites KW - Chromosomes KW - Evolution PY - 2024 AN - OPUS4-61255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Prajapati, Harshit Kumar T1 - Transmission-mediated adaptation in virulence of a major honeybee pathogen - Deformed Wing Virus N2 - The emergence of several infectious diseases in the last few decades has resulted in elevated honeybee (Apis mellifera) colony losses. Especially, (+) single-stranded RNA viruses like Deformed Wing Virus (DWV) have become prominent due to a novel vector from Asia, the ectoparasitic mite – Varroa destructor. The evolution of DWV may have been significantly affected by the establishment of a new transmission route, as represented by V. destructor. According to virulence-transmission trade-off theory, viruses found in vector-invaded hosts may evolve a level of virulence that maximizes transmission and subsequent spread in the colony. In this study, we tested this prediction by passaging DWV in white-eyed pupae by microinjection over 10 generations, to emulate the vectoring function of V. destructor, while subjecting the virus to 3 different transmission selection regimes: (i) Early: at 4 days, (ii) Optimal: at 6 days, and (iii) Late: at 8 days post-injection. The evolved viral genomes are analyzed by long-read (Oxford Nanopore) sequencing. The reconstructed viral population dynamics are compared with the inter-host transmission and viral load, to identify fixed mutations contributing to the adapted virulence. Using a site-/gene-specific test of natural selection, we explore the phenotypic effects of virulence among the evolved viruses. T2 - European IUSSI 2024 CY - Lausanne, Switzerland DA - 07.07.2024 KW - Evolution KW - Varroa destructor KW - Honeybees KW - Virus PY - 2024 AN - OPUS4-61720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - The interplay between biocides, phenotypic heterogeneity and resistance evolution N2 - An overview of the interplay between biocides, phenotypic heterogeneity and resistance evolution presented at the University Wroclaw. T2 - Invited seminar at the Department of Molecular Microbiology CY - Wroclaw, Poland DA - 08.04.2024 KW - Disinfectants KW - Biocide resistance KW - Phenotypic heterogeneity KW - Evolution PY - 2024 AN - OPUS4-61173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - EVOCIDE: Preserving disinfectant efficacy by predicting evolution: exposing the principles of disinfectant survival and adaptation in bacteria N2 - Presentation of the EVOCIDE research proposal work programme.EVOCIDE seeks to gain a systems level understanding of disinfectant survival and evolution in bacteria. T2 - Joint Group Seminar Rolff-McMahon-Armitage-Steiner CY - Berlin, Germany DA - 20.12.2023 KW - Disinfectants KW - Evolution KW - Microbiology KW - Bacteria KW - Biocides PY - 2023 AN - OPUS4-59224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - McMahon, Dino Peter T1 - Termite Immunity (a molecular perspective) N2 - In this presentation, an overview of the termite immune system is given. The presentation covers the mechanistic underpinnings of the canonical immune pathways in insects; where there are areas of conservation or divergence in termites, as well as briefly going over some key gaps in knowledge. External immune capabilities are discussed as well as the implications and consequences of sociality for the evolution of collective immune defense systems in termites. T2 - International Termite Course (ITC) 2025 CY - Davie, FL, USA DA - 10.06.2025 KW - Termite KW - Immunity KW - Molecular KW - Evolution PY - 2025 AN - OPUS4-64745 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection N2 - A presentation given at the VAAM conference 2022, summarizing our findings published in the research paper "Persistence against benzalkonium chloride promotes rapid evolution of tolerance under periodic disinfection" T2 - Annual conference of the association for general and applied microbiology (VAAM) 2022 CY - Düsseldorf, Germany DA - 21.02.2022 KW - Persistence KW - Biocides KW - Evolution KW - Cross-resistance KW - Biocide tolerance KW - Disinfection PY - 2022 AN - OPUS4-54437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - Consequences of BAC tolerance for selection and evolution in the presence of antibiotics N2 - The exposure to antimicrobial substances drives the evolution of antimicrobial resistance. Biocides are antimicrobials used as disinfectants, antiseptics and preservatives. They find application on a large scale in the industrial and medical sector, but also in private households. In terms of mass, the worldwide use of biocides exceeds that of antibiotics. Thus, despite their important role in preventing the spread of pathogens, due to their ubiquity, biocides are suspected to be drivers of the antimicrobial resistance crisis. In our work at BAM we try to understand how biocides contribute to the emergence of AMR, what the underlying adaptation principles and mechanisms are and how they compare to those found for antibiotics. Within our group, I mainly focus on the following two questions: How does phenotypic heterogeneity in bacteria affect the ability to survive treatment with biocides? And what are the consequences of phenotypic heterogeneity for the evolution of resistance to biocides and antibiotics? I will share published and unpublished results which demonstrate that phenotypic heterogeneity can enable the survival of biocide treatment and, through this, facilitate the evolution of AMR. On the other hand, we find that adaptation to a biocide can unexpectedly impair the ability to evolve resistance against an antibiotic. T2 - FEMS summer school for postdocs 2022: Microbial Evolvability Mechanisms: Resistance, Biology, and Strategies to Defeat and Detect CY - Split, Croatia DA - 27.04.2022 KW - Disinfection KW - Biocides KW - Evolution KW - Resistance KW - Biocide tolerance PY - 2022 AN - OPUS4-54846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobisch, Lydia-Yasmin T1 - Biocide resistance evolution of corrosion causing sulfate reducing bacteria N2 - SRB are environmentally and industrially important microorganisms. The disadvantage of their metabolic activity (e.g. sulfate reduction) results in the formation of toxic sulfide that leads to microbial influenced corrosion. SRB have been responsible for biocorrosion of ferrous metal. One of mitigation strategy is the use of biocides. However, it has been shown that various bacteria develop antimicrobial resistance due to excessive use of biocides. Thus, a deeper understanding of the evolution of biocide resistance of SRB is necessary. Three commonly used biocides, THPS, BAC, and GLUT were applied to investigate the susceptibility of Desulfovibrio alaskensis G20.The minimum inhibitory and bactericidal concentration and the killing kinetics of the three biocides was determined. These results will be used to conduct evolution experiments to determine the evolution of resistance towards biocides of SRBs. The outcome of this work can be helpful to improve the management of MIC treatments. T2 - Panel, Pitch & Popcorn by EUROMIC CY - Online meeting DA - 21.06.2021 KW - Biocide KW - Evolution KW - Mircobially influcenced corrosion KW - Sulfate reducing bacteria PY - 2021 AN - OPUS4-56940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nordholt, Niclas T1 - ALEE-AMC: Bacterial resistance evolution towards antimicrobial surfaces and development of a standardized test N2 - Background: Antimicrobial surfaces and coatings (AMCs) are important to protect man-made structures from biodeterioration and biodegradation. Advances in nano-structuring methods hold the promise of a new generation of AMCs. However, the evolution and selection of bacterial resistance to AMCs may threaten their efficacy in the long term. Therefore, according to the EU Biocidal Products Regulation, the risk of resistance development upon exposure to AMCs must be evaluated during product authorization. The same applies to the development of cross-resistances to other substances, for instance biocides and antibiotics. However, no standardized method exists to assess the risk of resistance and cross-resistance development upon exposure to AMCs during the authorization process. Objectives: • To develop a standardizable adaptive laboratory evolution experiment to be performed on AMCs (ALEE-AMC) • To assess performance and robustness of ALEE-AMC in a round robin test, using a copper AMC as reference • To uncover the mechanisms underlying evolution of resistance to copper AMC Materials & Methods: ALEE-AMC was developed based on an approved standard to determine the efficacy of antimicrobial surfaces (ISO 22196). ALEE-MC was performed on an antimicrobial copper surface as reference material and Escherichia coli as model organism. A round robin test was conducted with six participants to evaluate the reproducibility and applicability of ALEE-AMC. Evolved E. coli populations from the round robin partners were collected and subjected to phenotypic (antimicrobial susceptibility testing, ISO 22196) and genotypic (whole genome sequencing) characterization at BAM. Results: The results of the ALEE-AMC round robin test indicate that repeated exposure to copper can select for reduced copper susceptibility. However, failure of individual E. coli lineages to adapt to the copper surfaces was also observed. Evolved E. coli exhibited increased survival upon exposure to copper surfaces. Adaptation to copper did not induce cross-resistance to antibiotics. Whole genome sequencing of the evolved E. coli revealed high diversity of mutations among individual evolved strains, indicating the existence of multiple, underexplored evolutionary pathways towards increased survival of antimicrobial copper surfaces. Conclusion & Significance: ALEE-AMC offers a standardizable platform to assess the risk of resistance development towards novel and existing AMCs. Specifically, using ALEE-AMC in a round robin test, insights into evolvable survival mechanisms to copper AMCs have been gained. These mechanistic insights may be exploited to prevent the evolution against copper AMCs. In future steps, criteria need to be defined to provide guidelines for the authorization of AMCs based on the outcomes of ALEE-AMC T2 - International Biodeterioration and Biodegradation Symposium, Berlin, Germany CY - Berlin, Germany DA - 09.09.2024 KW - Biocides KW - Antimicrobial surfaces KW - Resistance KW - Evolution KW - Standardized test PY - 2024 AN - OPUS4-61176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -