Resistance to host antimicrobial peptides mediates resilience of gut commensals during infection and aging in Drosophila

Resilience to short-term perturbations, like inflammation, is a fundamental feature of microbiota, yet the underlying mechanisms of microbiota resilience are incompletely understood. Here, we show that Lactiplantibacillus plantarum, a major Drosophila commensal, stably colonizes the fruit fly gut during infection and is resistant to Drosophila antimicrobial peptides (AMPs). By transposon screening, we identified L. plantarum mutants sensitive to AMPs. These mutants were impaired in peptidoglycan O-acetylation or teichoic acid D-alanylation, resulting in increased negative cell surface charge and higher affinity to cationic AMPs. AMP-sensitive mutants were cleared from the gut after infection and aging-induced gut inflammation in wild-type, but not in AMP-deficient flies, suggesting that resistance to host AMPs is essential for commensal resilience in an inflamed gut environment. Thus, our work reveals that in addition to the host immune tolerance to the microbiota, commensal-encoded resilience mechanisms are necessary to maintain the stable association between host and microbiota during inflammation

The endosymbiont Spiroplasma poulsonii increases Drosophila melanogaster resistance to pathogens by enhancing iron sequestration and melanization

Facultative endosymbiotic bacteria, such as Wolbachia and Spiroplasma species, are commonly found in association with insects and can dramatically alter their host physiology. Many endosymbionts are defensive and protect their hosts against parasites or pathogens. Despite the widespread nature of defensive insect symbioses and their importance for the ecology and evolution of insects, the mechanisms of symbiont-mediated host protection remain poorly characterized. Here, we utilized the fruit fly Drosophila melanogaster and its facultative endosymbiont Spiroplasma poulsonii to characterize the mechanisms underlying symbiont-mediated host protection against bacterial and fungal pathogens. Our results indicate a variable effect of S. poulsonii on infection outcome, with endosymbiont-harboring flies being more resistant to Rhyzopus oryzae, Staphylococcus aureus, and Providencia alcalifaciens but more sensitive or as sensitive as endosymbiont-free flies to the infections with Pseudomonas species. Further focusing on the protective effect, we identified Transferrin-mediated iron sequestration induced by Spiroplasma as being crucial for the defense against R. oryzae and P. alcalifaciens. In the case of S. aureus, enhanced melanization in Spiroplasma-harboring flies plays a major role in protection. Both iron sequestration and melanization induced by Spiroplasma require the host immune sensor protease Persephone, suggesting a role of proteases secreted by the symbiont in the activation of host defense reactions. Hence, our work reveals a broader defensive range of Spiroplasma than previously appreciated and adds nutritional immunity and melanization to the defensive arsenal of symbionts

MprF-mediated immune evasion is necessary for Lactiplantibacillus plantarum resilience in the Drosophila gut during inflammation

Multiple peptide resistance factor (MprF) confers resistance to cationic antimicrobial peptides (AMPs) in several pathogens, thereby enabling evasion of the host immune response. The role of MprF in commensals remains, however, uncharacterized. To close this knowledge gap, we used a common gut commensal of animals, Lactiplantibacillus plantarum, and its natural host, the fruit fly Drosophila melanogaster, as an experimental model to investigate the role of MprF in commensal-host interactions. The L. plantarum ΔmprF mutant that we generated exhibited deficiency in the synthesis of lysyl-phosphatidylglycerol (Lys-PG), resulting in increased negative cell surface charge and increased susceptibility to AMPs. Susceptibility to AMPs had no effect on ΔmprF mutant’s ability to colonize guts of uninfected flies. However, we observed significantly reduced abundance of the ΔmprF mutant after infection-induced inflammation in the guts of wild-type flies but not of flies lacking AMPs. Additionally, we found that the ΔmprF mutant compared to wild-type L. plantarum induces a stronger intestinal immune response in flies due to the increased release of immunostimulatory peptidoglycan fragments, indicating an important role of MprF in promoting host tolerance to commensals. Our further analysis suggests that MprF-mediated lipoteichoic acid modifications are involved in host immunomodulation. Overall, our results demonstrate that MprF, besides its well-characterized role in pathogen immune evasion and virulence, is also an important commensal resilience factor

Estudo de misturas binarias e terciarias de cristais liquidos colestericos no intervalo de temperatura entre "60 GRAUS C a 150 GRAUS C

Dissertação (mestrado) - Universidade Federal de Santa Catarina. Centro de Ciencias Fisicas e MatematicasNo presente trabalho apresentou-se métodos e determinou-se sistemas de cristais líquidos colestéricos, para mapeamento térmico, operando em temperaturas acima de 100°C. Estudos já feitos, encontrados nas literaturas, apresentam sistemas para mapeamento térmico operando em um intervalo de 20°C a 60°C. Partindo destes dados um estudo preliminar foi feito com os compostos; cinamato de colesterila, nonanoato de colesterila, benzoato de colesterila, 2,4-diclorobenzoato de colesterila, hidrocinamato de colesterila, miristato de colesterila, cloreto de colesterila e outros mais, verificando o comportamento destes em misturas binárias e ternárias. Deste estudo preliminar surgiram dois sistemas que apresentaram melhores resultados. O primeiro sistema foi hidrocinamato mais 2,4-diclorobenzoato de colesterila e o segundo , hidrocinamato mais benzoato de colesterila. No primeiro sistema foi estudado a adição de cioreto de colesterila, onde se obteve sistemas funcionando até 150°C. No segundo sistema, além da adição de cloreto de colesterila foram também estudadas as adições de nonanoato e miristato de colesterila, resultando em sistemas operando em temperaturas entre 60°C a 120°C

Multibeam bathymetry raw data (Kongsberg EM 122 entire dataset) of RV MARIA S. MERIAN during cruise MSM64

Multibeam bathymetry raw data using the ship's own Kongsberg EM 712 multibeam echosounder was not continuously recorded during RV MARIA S. MERIAN cruise MSM64. Data was recorded on 2 days between 2017-05-30 and 2017-05-31 to perform a Sea Acceptance Test of the system. This dataset contains a survey west of the coast of Ireland. The approximate average depth of the entire dataset is around 2900m. 44 additional sound velocity profiles derived were generated on board, however no multibeam echosounder data were acquired in the vicinity of these events. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. Ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH, thus SVP files are added to this dataset. However, also data analysis of the multibeam raw data revealed that SVP has been changed during the survey. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be expected due to the lack of proper SVP. Overall, it appears that the data quality is partially good and partially bad since the gridded hillshade data showed relatively many fuzzy artifacts at the slant beams in the northern area of the survey, however the remaining survey in the southern area is mainly clear from artifacts. Data can be processed e.g. with the open source software package MB-System (Caress, D. W., and D. N. Chayes, MB-System: Mapping the Seafloor, http://www.mbari.org/products/research-software/mb-system/, 2022)

Water column raw data (Kongsberg EM 122 entire dataset) of RV MARIA S. MERIAN during cruise MSM64

Water column raw data using the ship's own Kongsberg EM 122 multibeam echosounder was not continuously recorded during RV MARIA S. MERIAN cruise MSM64. Data was recorded on 2 days between 2017-05-30 and 2017-05-31 to perform a Sea Acceptance Test of the system. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. Ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH and added to the corresponding multibeam raw dataset https://doi.org/10.1594/PANGAEA.944239 This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM)

Transcriptional changes after <i>Pa</i> infection.

MA plot of the Drosophila transcriptome showing log2 Fold change expression in wild-type flies (w1118 iso) infected with Providencia alcalifaciens/ unchallenged, (x-axis) and (y-axis) after 6h (A) and 20h (B). Red and blue dots indicated differentially upregulated and down-regulated transcripts, respectively. (C) Venn diagram showing overlap between upregulated genes at 6h and 20h post infection. (D-F) Bar plots showing the enrichment of GO terms of global biological properties with significant gene counts upregulated at 6h (D) and 20h (E). (F) blue bar plots showing GO terms with down-regulated gene counts at 20h. P-adjusted values next to the bars.</p