Propionibacterium acnes is regarded as a common member of the human skin microbiota, often occurring in biofilms. Little is known about the size of bacterial biofilms in hair follicles as a few ...sections of biopsy tissue are routinely evaluated. Transversal sectioning provides a better opportunity for histological analyses of hair follicles which can be followed through the different morphological levels. Direct visualization of P. acnes biofilms in hundreds of consecutive sections allowed insight into the 3D distribution in human hair follicles as well as investigating the depth of biofilm distribution within hair follicles. Four distinct colonization patterns of P. acnes biofilms were revealed. Results have shown that an individual P. acnes biofilm can spread for 1900 μm in a terminal hair follicle. This information can be of help while designing potential antibiofilm treatment.
Propionibacterium acnes is a well-known commensal of the human skin connected to acne vulgaris and joint infections. It is extensively studied in planktonic cultures in the laboratory settings but ...occurs naturally in biofilms. In this study we have developed an in vitro biofilm model of P. acnes and studied growth features, matrix composition, matrix penetration by fluorescent-labeled antibiotics as well as gene expression. Antibiotic susceptibility of biofilms was studied and could be enhanced by increased glucose concentrations. Biofilm cells were characterized by up-regulated stress-induced genes and up-regulation of genes coding for the potential virulence-associated CAMP factors. P. acnes can generate persister cells showing a reversible tolerance to 50 fold MIC of common antibiotics.
•P. acnes inhabits the skin and is found predominantly in hair follicles as biofilms.•The P. acnes biofilm matrix is penetrable for antibiotics.•Biofilm cells show same antibiotic susceptibility as free-living counterparts.•P. acnes can generate persister cells showing a reversible tolerance to 50 fold MIC of antibiotics.
Acne vulgaris is the most common dermatological disorder worldwide affecting more than 80% of adolescents and young adults with a global prevalence of 231 million cases in 2019. The involvement of ...the skin microbiome disbalance in the pathophysiology of acne is recognized, especially regarding the relative abundance and diversity of
a well-known dominant human skin commensal. Biofilms, where bacteria are embedded into a protective polymeric extracellular matrix, are the most prevalent life style for microorganisms.
and its biofilm-forming ability is believed to be a contributing factor in the development of acne vulgaris, the persistence of the opportunistic pathogen and antibiotic therapy failures. Degradation of the extracellular matrix is one of the strategies used by bacteria to disperse the biofilm of competitors. In this study, we report the identification of an endogenous extracellular nuclease, BmdE, secreted by
able to degrade
biofilm both
and
. This, to our knowledge, may represent a novel competitive mechanism between two closely related species in the skin. Antibiotics targeting
have been the mainstay in acne treatment. Extensive and long-term use of antibiotics has led to the selection and spread of resistant bacteria. The extracellular DNase BmdE may represent a new bio-therapeutical strategy to combat
biofilm in acne vulgaris.
Polyhydroxyalkanoates (PHAs) are naturally occurring organic polyesters that are of interest for industrial and biomedical applications. These polymers are synthesized by most bacteria in times of ...unbalanced nutrient availability from a variety of substrates and they are deposited intracellularly as insoluble spherical inclusions or PHA granules. The granules consist of a polyester core, surrounded by a boundary layer with embedded or attached proteins that include the PHA synthase, phasins, depolymerizing enzymes, and regulatory proteins. Apart from ongoing industrial interest in the material PHA, more recently there has also been increasing interest in applications of the PHA granules as nano-/micro-beads after it was conceived that fusions to the granule associated proteins (GAPs) provide a way to immobilize target proteins at the granule surface. This review gives an overview of PHA granules in general, including biogenesis and GAPs, and focuses on their potential use as nano-/micro-beads in biotechnological and biomedical applications.
Hidradenitis suppurativa (acne inverse) (HS) is a chronic skin disease primarily affecting hair follicles. The aetiology of HS is unknown, but infection is believed to play some role. This ...retrospective study investigated the microbial colonization directly in skin appendices in HS skin samples. Archival samples from 27 patients with HS were screened by immunofluorescence labelling with monoclonal and polyclonal antibodies against Gram‐positive bacteria, Propionibacterium acnes and Propionibacterium granulosum. Fluorescence in situ hybridization was used for further species identification of Staphylococcus spp. Overall, 17 patients (63%) were found positive for bacterial colonization. Of these, 15 showed colonization in hair follicles and/or sinus tracts. The most commonly identified bacteria were DAPI labelled coccoids that were seen in 71% of the positive patients in the form of biofilms and microcolonies. P. acnes was found as biofilms in hair follicles of two patients. Staphylococcus aureus and coagulase‐negative staphylococci were not detected in any sample. The results of this study indicate a common bacterial presence in HS skin lesions. Bacterial biofilms are not uncommon and their pathogenic role needs further evaluation.
Recent genetic studies have suggested the presence of numerous microbial species on and in the skin. We characterised microbial colonization of a large collection of skin biopsies from 194 healthy ...subjects by fluorescence assay. Forty per cent of all biopsies did not show any evidence for microbial colonization. Propionibacterium acnes was the sole predominant bacterial species in both sebaceous and non-sebaceous areas. Non- P. acnes species were present in approximately 30% of all colonized samples. . Only hair follicles and stratum corneum were colonized. Understanding of cutaneous microbiota requires validation from a variety of approaches and techniques.
•Propionibacterium acnes is a common member of the skin microbiome.•A large proportion of skin samples showed no evidence of microbial colonization.•P. acnes is the predominant bacterial species in sebaceous and non-sebaceous areas.•Direct visualization enumerates less species than recent genetic studies suggested.
Here, the class I polyhydroxyalkanoate synthase (PhaC) from Ralstonia eutropha was investigated regarding the functionality of its conserved C-terminal region and its ability to tolerate ...translational fusions to its C terminus. MalE, the maltose binding protein, and green fluorescent protein (GFP) were considered reporter proteins to be translationally fused to the C terminus. Interestingly, PhaC remained active only when a linker was inserted between PhaC and MalE, whereas MalE was not functional. However, the extension of the PhaC N terminus by 458 amino acid residues was required to achieve a functionality of MalE. These data suggested a positive interaction of the extended N terminus with the C terminus. To assess whether a linker and/or N-terminal extension is generally required for a functional C-terminal fusion, GFP was fused to the C terminus of PhaC. Both fusion partners were active without the requirement of a linker and/or N-terminal extension. A further reporter protein, the immunoglobulin G binding ZZ domain of protein A, was translationally fused to the N terminus of the fusion protein PhaC-GFP and resulted in a tripartite fusion protein mediating the production of polyester granules displaying two functional protein domains.
Summary
Proteins are often found attached to surfaces of self‐assembling biological units such as whole microbial cells or subcellular structures, e.g. intracellular inclusions. In the last two ...decades surface proteins were identified that could serve as anchors for the display of foreign protein functions. Extensive protein engineering based on structure–function data enabled efficient display of technically and/or medically relevant protein functions. Small size, diversity of the anchor protein as well as support structure, genetic manipulability and controlled cultivation of phages, bacterial cells and yeasts contributed to the establishment of designed and specifically functionalized tools for applications as sensors, catalysis, biomedicine, vaccine development and library‐based screening technologies. Traditionally, phage display is employed for library screening but applications in biomedicine and vaccine development are also perceived. For some diagnostic purposes phages are even too small in size so other carrier materials where needed and gave way for cell and yeast display. Only recently, intracellular inclusions such as magnetosomes, polyhydroxyalkanoate granules and lipid bodies were conceived as stable subcellular structures enabling the display of foreign protein functions and showing potential as specific and tailor‐made devices for medical and biotechnological applications.
Multifunctional shell−core nano/microbeads with a hydrophobic biopolymer core and a designed protein coat for selective binding of an inorganic substance and antibodies were self-assembled inside ...engineered bacteria. Hybrid genes were constructed to produce tailormade bead-coating proteins in the bacterium Escherichia coli. These fusion proteins contained a binding peptide for an inorganic material, the antibody binding ZZ domain, and a self-assembly promoting as well as biopolymer synthesizing enzyme. Production of these multidomain fusion proteins inside E. coli resulted in self-assembly of beads comprising a biopolyester core and displaying covalently bound binding sites for specific and selective binding of an inorganic substance and any antibody belonging to the immunoglobulin G class. Engineered beads were isolated and purified from the respective E. coli cells by standard cell disruption procedures. Bead morphology and the binding functionalities displayed at the bead surface were assessed by the enzyme-linked immunosorbent assay, transmission electron microscopy, elemental analysis, backscattering electron density, analytical density ultracentrifugation, and atomic force microscopy. These analyses showed that bacteria can be engineered to produce fusion proteins mediating self-assembly of spherical biopolymer beads with binding affinity to gold and/or silica and antibodies. Spherical structures of this type could conceivably serve as nano/microdevices for bioimaging in medical approaches where an antibody mediated targeted delivery of an inorganic contrast agent would be desired.
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