333 results match your criteria: "Hans Knöll Institute - HKI[Affiliation]"

The proteomic response of to amphotericin B (AmB) reveals the involvement of the RTA-like protein RtaA in AmB resistance.

Microlife

December 2024

Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Adolf-Reichwein-Str. 23, 07745 Jena, Germany.

The polyene antimycotic amphotericin B (AmB) and its liposomal formulation AmBisome belong to the treatment options of invasive aspergillosis caused by . Increasing resistance to AmB in clinical isolates of species is a growing concern, but mechanisms of AmB resistance remain unclear. In this study, we conducted a proteomic analysis of exposed to sublethal concentrations of AmB and AmBisome.

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Photosynthetic protists, named microalgae, are key players in global primary production. The green microalga Chlamydomonas reinhardtii is a well-studied model organism. In nature, it dwells in acetate-rich paddy rice soil, which is not mimicked by standard liquid laboratory conditions.

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In early 2024, the National Academies of Sciences, Engineering, and Medicine (NASEM) released a roadmap for the future of research into mapping ribonucleic acid (RNA) modifications, which underscored the importance of better defining these diverse chemical changes to the RNA macromolecule. As nearly all mature RNA molecules harbor some form of modification, we must understand RNA modifications to fully appreciate the functionality of RNA. The NASEM report calls for massive mobilization of resources and investment akin to the transformative Human Genome Project of the early 1990s.

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To sense or not to sense, Paneth cell regulation of mucosal immunity.

Cell Host Microbe

October 2024

Institute for Infectious Disease and Infection Control, Jena University Hospital, Friedrich Schiller University, 07747 Jena, Germany; Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Friedrich Schiller University, 07747 Jena, Germany; Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), 07745 Jena, Germany.

Article Synopsis
  • - Paneth cells in the intestinal crypts help support stem cells and immunity by producing growth factors and antimicrobial peptides.
  • - A study by Wallaeys et al. discusses how these Paneth cells respond to TNF (tumor necrosis factor), which affects their ability to manage stress in proteins.
  • - This disruption leads to a decrease in antimicrobial peptides, increasing the risk of bacteria moving into the bloodstream and potentially causing sepsis.
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The use of compounds produced by hosts or symbionts for defence against antagonists has been identified in many organisms, including in fungus-farming termites (Macrotermitinae). The obligate mutualistic fungus Termitomyces plays a pivotal role in plant biomass decomposition and as the primary food source for these termites. Despite the isolation of various specialized metabolites from different Termitomyces species, our grasp of their natural product repertoire remains incomplete.

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Bacteria from the Amycolatopsis genus associated with a toxic bird secrete protective secondary metabolites.

Nat Commun

October 2024

Anti-infectives from Microbiota, Helmholtz-Institut für Pharmazeutische Forschung Saarland (HIPS), Campus E8.1, 66123, Saarbrücken, Germany.

Uropygial gland secretions of birds consist of host and bacteria derived compounds and play a major sanitary and feather-protective role. Here we report on our microbiome studies of the New Guinean toxic bird Pachycephala schlegelii and the isolation of a member of the Amycolatopsis genus from the uropygial gland secretions. Bioactivity studies in combination with co-cultures, MALDI imaging and HR-MS/MS-based network analyses unveil the basis of its activity against keratinolytic bacteria and fungal skin pathogens.

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Article Synopsis
  • The study examined how often and significantly Herpes simplex virus (HSV) reactivates in patients with community-acquired pneumonia (CAP) and identified potential risk factors.
  • It analyzed data from adult CAP patients in the CAPNETZ study (2007-2017), where both sputum and blood samples were tested for HSV, focusing on demographics and clinical outcomes.
  • Results showed that HSV-1 was present in 12.2% of patients, but its presence didn’t correlate with worse outcomes, suggesting that while HSV reactivation is common, it may not complicate the disease significantly.
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Increased peritoneal B1-like cells during acute phase of human septic peritonitis.

iScience

July 2024

Department of Biochemistry, Center for Molecular Biomedicine (CMB), Friedrich Schiller University, Hans-Knöll-Str. 2, 07745 Jena, Germany.

Sepsis is a life-threatening condition caused by dysregulated host responses to infection. Myeloid cell accumulation and lymphocyte decline are widely recognized phenomena in septic patients. However, the fate of specific immune cells remains unclear.

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Variations in candidalysin amino acid sequence influence toxicity and host responses.

mBio

August 2024

Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, London, United Kingdom.

Article Synopsis
  • Candidalysin is a toxin produced by Candida species, playing a significant role in causing mucosal infections and damaging host tissues, which exacerbates diseases and immune responses.* -
  • Recent studies discovered multiple variants of candidalysin in different Candida isolates, indicating a wider genetic diversity and potential differences in how they affect host cells.* -
  • Experiments showed that these candidalysin variants cause varying levels of cellular damage and biological responses in epithelial cells, highlighting their importance in understanding fungal infections.*
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an opportunistic fungal pathogen, produces the quorum-sensing molecule farnesol, which we have shown alters the transcriptional response and phenotype of human monocyte-derived dendritic cells (DCs), including their cytokine secretion and ability to prime T cells. This is partially dependent on the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-γ), which has numerous ligands, including the sphingolipid metabolite sphingosine 1-phosphate. Sphingolipids are a vital component of membranes that affect membrane protein arrangement and phagocytosis of by DCs.

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The candidate phyla radiation (CPR) represents a distinct monophyletic clade and constitutes a major portion of the tree of life. Extensive efforts have focused on deciphering the functional diversity of its members, primarily using sequencing-based techniques. However, cultivation success remains scarce, presenting a significant challenge, particularly in CPR-dominated groundwater microbiomes characterized by low biomass.

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Invasive aspergillosis causes significant morbidity and mortality in immunocompromised patients. Natural killer (NK) cells are pivotal for antifungal defense. Thus far, CD56 is the only known pathogen recognition receptor on NK cells triggering potent antifungal activity against Aspergillus fumigatus.

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Fungi constitute the Earth's second most diverse kingdom, however only a small percentage of these have been thoroughly examined and categorized for their secondary metabolites, which still limits our understanding of the ecological chemical and pharmacological potential of fungi. In this study, we explored members of the co-evolved termite-associated fungal genus Xylaria and identified a family of highly oxygenated polyketide-terpene hybrid natural products using an MS/MS molecular networking-based dereplication approach. Overall, we isolated six no yet reported xylasporin derivatives, of which xylasporin A (1) features a rare cyclic-carbonate moiety.

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Cervimycins A-D are bis-glycosylated polyketide antibiotics produced by HKI 0179 with bactericidal activity against Gram-positive bacteria. In this study, cervimycin C (CmC) treatment caused a spaghetti-like phenotype in 168, with elongated curved cells, which stayed joined after cell division, and exhibited a chromosome segregation defect, resulting in ghost cells without DNA. Electron microscopy of CmC-treated (3 × MIC) revealed swollen cells, misshapen septa, cell wall thickening, and a rough cell wall surface.

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Introduction: Sepsis remains the major cause of death among hospitalised patients in intensive care. While targeting sepsis-causing pathogens with source control or antimicrobials has had a dramatic impact on morbidity and mortality of sepsis patients, this strategy remains insufficient for about one-third of the affected individuals who succumb. Pharmacological targeting of mechanisms that reduce sepsis-defining organ dysfunction may be beneficial.

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Genome-Driven Discovery of Hygrocins in .

J Nat Prod

May 2024

Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 221, 2800 Kgs. Lyngby, Denmark.

Article Synopsis
  • * Researchers fermented IMET 43975 to isolate five known and four new ansamycin analogues, including new compounds called hygrocins.
  • * The structural analysis of these ansamycins was conducted using advanced techniques, and a specific enzyme involved in their formation was confirmed through CRISPR base editing, enhancing our understanding of their diversity.
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Early identification of human pathogens is crucial for the effective treatment of bloodstream infections to prevent sepsis. Since pathogens that are present in small numbers are usually difficult to detect directly, we hypothesize that the behavior of the immune cells that are present in large numbers may provide indirect evidence about the causative pathogen of the infection. We previously applied time-lapse microscopy to observe that neutrophils isolated from human whole-blood samples, which had been infected with the human-pathogenic fungus or , indeed exhibited a characteristic morphodynamic behavior.

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The cosmopolitan marine Roseobacter clade is of global biogeochemical importance. Members of this clade produce sulfur-containing amino lipids (SALs) involved in biofilm formation and marine surface colonization processes. Despite their physiological relevance and abundance, SALs have only been explored through genomic mining approaches and lipidomic studies based on mass spectrometry, which left the relative and absolute structures of SALs unresolved, hindering progress in biochemical and functional investigations.

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Regulatory T (TREG) cells develop via a program orchestrated by the transcription factor forkhead box protein P3 (FOXP3). Maintenance of the TREG cell lineage relies on sustained FOXP3 transcription via a mechanism involving demethylation of cytosine-phosphate-guanine (CpG)-rich elements at conserved non-coding sequences (CNS) in the FOXP3 locus. This cytosine demethylation is catalyzed by the ten-eleven translocation (TET) family of dioxygenases, and it involves a redox reaction that uses iron (Fe) as an essential cofactor.

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Unlabelled: () is a dominant species in the human gut microbiota and considered a beneficial bacterium for producing probiotic butyrate. However, recent studies have suggested that may negatively affect the host through synthesizing fatty acid and metabolizing the anticancer drug 5-fluorouracil, indicating that the impact of is complex and unclear. Therefore, comprehensive genomic studies on need to be performed.

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The fungus Candida albicans frequently colonizes the human gastrointestinal tract, from which it can disseminate to cause systemic disease. This polymorphic species can transition between growing as single-celled yeast and as multicellular hyphae to adapt to its environment. The current dogma of C.

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The opportunistic fungal pathogen Candida albicans damages host cells via its peptide toxin, candidalysin. Before secretion, candidalysin is embedded in a precursor protein, Ece1, which consists of a signal peptide, the precursor of candidalysin and seven non-candidalysin Ece1 peptides (NCEPs), and is found to be conserved in clinical isolates. Here we show that the Ece1 polyprotein does not resemble the usual precursor structure of peptide toxins.

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Exploring phenazine electron transfer interaction with elements of the respiratory pathways of Pseudomonas putida and Pseudomonas aeruginosa.

Bioelectrochemistry

June 2024

Bio Pilot Plant, Leibniz Institute for Natural Product Research and Infection Biology - Hans-Knöll-Institute (HKI), Beutenbergstr. 11a, 07745 Jena, Germany; Faculty of Biological Sciences, Friedrich Schiller University (FSU), Fürstengraben 1, 07743 Jena, Germany. Electronic address:

Pseudomonas aeruginosa phenazines contribute to survival under microaerobic and anaerobic conditions by extracellular electron discharge to regulate cellular redox balances. This electron discharge is also attractive to be used for bioelectrochemical applications. However, elements of the respiratory pathways that interact with phenazines are not well understood.

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Sepsis remains a major cause of morbidity and mortality in both low- and high-income countries. Antibiotic therapy and supportive care have significantly improved survival following sepsis in the twentieth century, but further progress has been challenging. Immunotherapy trials for sepsis, mainly aimed at suppressing the immune response, from the 1990s and 2000s, have largely failed, in part owing to unresolved patient heterogeneity in the underlying immune disbalance.

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Inflammatory bowel disease (IBD) has become a globally prevalent chronic disease with no causal therapeutic options. Targeted drug delivery systems with selectivity for inflamed areas in the gastrointestinal tract promise to reduce severe drug-related side effects. By creating three distinct nanostructures (vesicles, spherical, and wormlike micelles) from the same amphiphilic block copolymer poly(butyl acrylate)-block-poly(ethylene oxide) (PBA-b-PEO), the effect of nanoparticle shape on human mucosal penetration is systematically identified.

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