Diversity of Neurotransmitter-Producing Human Skin Commensals.

Recent findings indicate that human microbiota can excrete trace amines, dopamine, and serotonin. These neurotransmitters (NTs) can either affect classical neurotransmitter signaling or directly trigger trace amine-associated receptors (TAARs), with still unclear consequences for host physiology. Compared to gut microbiota, less information is available on the role of skin microbiota in NT production.

SLUSH peptides of the PSMβ family enable Staphylococcus lugdunensis to use erythrocytes as a sole source of nutrient iron.

During infection, the host employs nutritional immunity to restrict access to iron. Staphylococcus lugdunensis has been recognized for its ability to utilize host-derived heme to overcome iron restriction. However, the mechanism behind this process involves the release of hemoglobin from erythrocytes, and the hemolytic factors of S.

From an Hsp90 - binding protein to a peptide drug.

The Lpl proteins represent a class of lipoproteins that was first described in the opportunistic bacterial pathogen , where they contribute to pathogenicity by enhancing F-actin levels of host epithelial cells and thereby increasing internalization. The model Lpl protein, Lpl1 was shown to interact with the human heat shock proteins Hsp90α and Hsp90ß, suggesting that this interaction may trigger all observed activities. Here we synthesized Lpl1-derived peptides of different lengths and identified two overlapping peptides, namely, L13 and L15, which interacted with Hsp90α.

Phenol-soluble modulin α and β display divergent roles in mice with staphylococcal septic arthritis.

Phenol-soluble modulin α (PSMα) is identified as potent virulence factors in Staphylococcus aureus (S. aureus) infections. Very little is known about the role of PSMβ which belongs to the same toxin family.

Depends on Eap Proteins for Preventing Degradation of Its Phenol-Soluble Modulin Toxins by Neutrophil Serine Proteases.

Neutrophil granulocytes act as a first line of defense against pathogenic staphylococci. However, has a remarkable capacity to survive neutrophil killing, which distinguishes it from the less-pathogenic Both species release phenol-soluble modulin (PSM) toxins, which activate the neutrophil formyl-peptide receptor 2 (FPR2) to promote neutrophil influx and phagocytosis, and which disrupt neutrophils or their phagosomal membranes at high concentrations. We show here that the neutrophil serine proteases (NSPs) neutrophil elastase, cathepsin G and proteinase 3, which are released into the extracellular space or the phagosome upon neutrophil FPR2 stimulation, effectively degrade PSMs thereby preventing their capacity to activate and destroy neutrophils.

New insights in the coordinated amidase and glucosaminidase activity of the major autolysin (Atl) in Staphylococcus aureus.

After bacterial cell division, the daughter cells are still covalently interlinked by the peptidoglycan network which is resolved by specific hydrolases (autolysins) to release the daughter cells. In staphylococci, the major autolysin (Atl) with its two domain enzymes, N-acetylmuramyl-L-alanine amidase (AmiA) and β-N-acetylglucosaminidase (GlcA), resolves the peptidoglycan to release the daughter cells. Internal deletions in each of the enzyme domains revealed defined morphological alterations such as cell cluster formation in ΔamiA, ΔglcA and Δatl, and asymmetric cell division in the ΔglcA.

Inactivation of Causes High Rhodomyrtone Resistance and Increased Pathogenicity in .

Rhodomyrtone (Rom) is an acylphloroglucinol antibiotic originally isolated from leaves of . Rom targets the bacterial membrane and is active against a wide range of Gram-positive bacteria but the exact mode of action remains obscure. Here we isolated and characterized a spontaneous Rom-resistant mutant from the model strain HG001 (Rom) to learn more about the resistance mechanism.

Gain-of-Function Mutations in the Phospholipid Flippase MprF Confer Specific Daptomycin Resistance.

Daptomycin, a calcium-dependent lipopeptide antibiotic whose full mode of action is still not entirely understood, has become a standard-of-care agent for treating methicillin-resistant (MRSA) infections. Daptomycin-resistant (DAP-R) mutants emerge during therapy, featuring isolates which in most cases possess point mutations in the gene. MprF is a bifunctional bacterial resistance protein that synthesizes the positively charged lipid lysyl-phosphatidylglycerol (LysPG) and translocates it subsequently from the inner membrane leaflet to the outer membrane leaflet.

The Mechanism behind Bacterial Lipoprotein Release: Phenol-Soluble Modulins Mediate Toll-Like Receptor 2 Activation via Extracellular Vesicle Release from Staphylococcus aureus.

The innate immune system uses Toll-like receptor (TLR) 2 to detect conserved bacterial lipoproteins of invading pathogens. The lipid anchor attaches lipoproteins to the cytoplasmic membrane and prevents their release from the bacterial cell envelope. How bacteria release lipoproteins and how these molecules reach TLR2 remain unknown.

Genetic Adaptation of a Mevalonate Pathway Deficient Mutant in .

In this study we addressed the question how a mevalonate (MVA)-auxotrophic Δ mutant can revert to prototrophy. This mutant couldn't grow in the absence of MVA. However, after a long lag-phase of 4-6 days the mutant adapted from auxotrophic to prototrophic phenotype.

Determinants of depression among people with epilepsy in Central Ethiopia.

Background: Depression is the most frequently and highly occurring mental disorders in epilepsy patients. When depression is comorbid with epilepsy, it leads to low employment and poor quality of life. Thus, the aim of this study was to assess the prevalence and associated factors of depression among people living with epilepsy in Central Ethiopia.

SadA-Expressing Staphylococci in the Human Gut Show Increased Cell Adherence and Internalization.

A subgroup of biogenic amines, the so-called trace amines (TAs), are produced by mammals and bacteria and can act as neuromodulators. In the genus Staphylococcus, certain species are capable of producing TAs through the activity of staphylococcal aromatic amino acid decarboxylase (SadA). SadA decarboxylates aromatic amino acids to produce TAs, as well as dihydroxy phenylalanine and 5-hydroxytryptophan to thus produce the neurotransmitters dopamine and serotonin.

Lpl Lipoproteins Delay G2/M Phase Transition in HeLa Cells.

The cell cycle is an ordered set of events, leading to cell growth and division into two daughter cells. The eukaryotic cell cycle consists of interphase (G, S, and G phases), followed by the mitotic phase and G phase. Many bacterial pathogens secrete cyclomodulins that interfere with the host cell cycle.

Excreted Cytoplasmic Proteins Contribute to Pathogenicity in Staphylococcus aureus.

Excretion of cytoplasmic proteins in pro- and eukaryotes, also referred to as "nonclassical protein export," is a well-known phenomenon. However, comparatively little is known about the role of the excreted proteins in relation to pathogenicity. Here, the impact of two excreted glycolytic enzymes, aldolase (FbaA) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), on pathogenicity was investigated in Staphylococcus aureus Both enzymes bound to certain host matrix proteins and enhanced adherence of the bacterial cells to host cells but caused a decrease in host cell invasion.

VraH Is the Third Component of the Staphylococcus aureus VraDEH System Involved in Gallidermin and Daptomycin Resistance and Pathogenicity.

In bacteria, extracellular signals are transduced into the cell predominantly by two-component systems (TCSs) comprising a regulatory unit triggered by a specific signal. Some of the TCSs control executing units such as ABC transporters involved in antibiotic resistance. For instance, inStaphylococcus aureus, activation of BraSR leads to the upregulation ofvraDEexpression that encodes an ABC transporter playing a role in bacitracin and nisin resistance.

Excretion of cytoplasmic proteins (ECP) in Staphylococcus aureus.

Excretion of cytoplasmic proteins (ECP) is a common physiological feature in bacteria and eukaryotes. However, how these proteins without a typical signal peptide are excreted in bacteria is poorly understood. We studied the excretion pattern of cytoplasmic proteins using two glycolytic model enzymes, aldolase and enolase, and show that their excretion takes place mainly during the exponential growth phase in Staphylococcus aureus very similar to that of Sbi, an IgG-binding protein, which is secreted via the Sec-pathway.

Distinct mechanisms contribute to immunity in the lantibiotic NAI-107 producer strain Microbispora ATCC PTA-5024.

The investigation of self-resistance in antibiotic producers is important to understand the emergence of antibiotic resistance in pathogens and to improve antibiotic production. Lantibiotics are ribosomally synthesized antibiotics that mostly target peptidoglycan biosynthesis. The actinomycete Microbispora ATCC PTA-5024 produces the lantibiotic NAI-107, which interferes with peptidoglycan biosynthesis by binding bactoprenol-pyrophosphate-coupled peptidoglycan precursors.

Secretome analysis revealed adaptive and non-adaptive responses of the Staphylococcus carnosus femB mutant.

FemABX peptidyl transferases are involved in non-ribosomal pentaglycine interpeptide bridge biosynthesis. Here, we characterized the phenotype of a Staphylococcus carnosus femB deletion mutant, which was affected in growth and showed pleiotropic effects such as enhanced methicillin sensitivity, lysostaphin resistance, cell clustering, and decreased peptidoglycan cross-linking. However, comparative secretome analysis revealed a most striking difference in the massive secretion or release of proteins into the culture supernatant in the femB mutant than the wild type.

Structural and functional analysis of Bacillus subtilis YisP reveals a role of its product in biofilm production.

YisP is involved in biofilm formation in Bacillus subtilis and has been predicted to produce C30 isoprenoids. We determined the structure of YisP and observed that it adopts the same fold as squalene and dehydrosqualene synthases. However, the first aspartate-rich motif found in essentially all isoprenoid synthases is aspartate poor in YisP and cannot catalyze head-to-head condensation reactions.

The role of serum proteins in Staphylococcus aureus adhesion to ethylene glycol coated surfaces.

Bacterial adhesion on implants is a first step in the development of chronic foreign body associated infections. Finding strategies to minimize bacterial adhesion may contribute to minimize such infections. It is known that surfaces with oligo-ethylene-glycol (EG3OMe) or poly-ethylene-glycol (PEG2k) terminations decrease unspecific protein adsorption and bacterial adhesion.

Structure-function analysis of Staphylococcus aureus amidase reveals the determinants of peptidoglycan recognition and cleavage.

The bifunctional major autolysin AtlA of Staphylococcus aureus cleaves the bacterium's peptidoglycan network (PGN) at two distinct sites during cell division. Deletion of the enzyme results in large cell clusters with disordered division patterns, indicating that AtlA could be a promising target for the development of new antibiotics. One of the two functions of AtlA is performed by the N-acetylmuramyl-l-alanine amidase AmiA, which cleaves the bond between the carbohydrate and the peptide moieties of PGN.

Nutrient limitation governs Staphylococcus aureus metabolism and niche adaptation in the human nose.

Colonization of the human nose by Staphylococcus aureus in one-third of the population represents a major risk factor for invasive infections. The basis for adaptation of S. aureus to this specific habitat and reasons for the human predisposition to become colonized have remained largely unknown.