Biology subjects

Slavetinsky, C. J.

Publications and source records attributed to Slavetinsky, C. J..

4 recordsLinked to original sources

bioRxiv2023

Wall teichoic acid substitution with glucose governs phage susceptibility of Staphylococcus epidermidis

The species- and clone-specific susceptibility of Staphylococcus cells for bacteriophages is governed by the structures and glycosylation patterns of wall teichoic acid (WTA) glycopolymers. The glycocodes of phage-WTA interaction in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative staphylococci (CoNS) have remained unknown. We report a new S. epidermidis WTA glycosyltransferase TagE whose deletion confers resistance to siphoviruses such as {Phi}E72 but enables binding of otherwise unbound podoviruses. S. epidermidis glycerolphosphate WTA was found to be modified with glucose in a tagE-dependent manner. TagE is encoded together with the enzymes PgcA and GtaB providing uridine diphosphate-activated glucose. {Phi}E72 transduced several other CoNS species encoding TagE homologs suggesting that WTA glycosylation via TagE is a frequent trait among CoNS that permits inter-species horizontal gene transfer. Our study unravels a crucial mechanism of phage-Staphylococcus interaction and of horizontal gene transfer and it will help in the design of anti-staphylococcal phage therapies. ImportancePhages are highly specific for certain bacterial hosts, and some can transduce DNA even across species boundaries. How phages recognize cognate host cells remains incompletely understood. Phages infecting members of the genus Staphylococcus bind to wall teichoic acid (WTA) glycopolymers with highly variable structures and glycosylation patterns. How WTA is glycosylated in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative Staphylococcus (CoNS) species has remained unknown. We describe that S. epidermidis glycosylates its WTA backbone with glucose and we identify a cluster of three genes, responsible for glucose activation and transfer to WTA. Their inactivation strongly alters phage susceptibility patterns, yielding resistance to siphoviruses but susceptibility to podoviruses. Many different CoNS species with related glycosylation genes can exchange DNA via siphovirus {Phi}E72 suggesting that glucose-modified WTA is crucial for interspecies horizontal gene transfer. Our finding will help to develop antibacterial phage therapies and unravel routes of genetic exchange.

microbiology↗

bioRxiv2023

The capsular polysaccharide obstructs wall teichoic acid functions in Staphylococcus aureus

BackgroundThe cell envelope of Staphylococcus aureus contains two major secondary cell wall glycopolymers: capsular polysaccharide (CP) and wall teichoic acid (WTA). Both the CP and the WTA are attached to the cell wall and play distinct roles in S. aureus colonization, pathogenesis, and bacterial evasion of host immune defenses. ObjectiveWe aimed to investigate whether CP interferes with WTA-mediated properties. MethodsStrains with natural heterogeneous expression of CP, strains with homogeneous high CP expression and CP-deficient strains were compared to WTA deficient controls regarding WTA dependent phage binding, cell adhesion, IgG deposition, and virulence in vivo. ResultsWTA-mediated phage adsorption, specific antibody deposition and cell adhesion were negatively correlated with CP expression. WTA, but not CP, enhanced the bacterial burden in a mouse abscess model, while CP overexpression resulted in intermediate virulence in vivo. ConclusionsCP protects the bacteria from WTA-dependent opsonization and phage binding. This protection comes at the cost of diminished adhesion to host cells. The highly complex regulation and mostly heterogeneous expression of CP has probably evolved to ensure the survival and optimal physiological adaptation of the bacterial population as a whole.

microbiology↗

bioRxiv2022

Prokaryotic phospholipid translocation by ubiquitous PplT domain proteins

Flippase proteins exchanging phospholipids between the cytoplasmic membrane leaflets have been identified in Eukaryotes but remained largely unknown in Prokaryotes. Only MprF proteins that synthesize aminoacyl phospholipids in some bacteria have been found to contain a domain that translocates the produced lipids. We show here that this domain, which we named prokaryotic phospholipid translocator (PplT), is widespread in Bacteria and Archaea, encoded as a separate protein or fused to different types of enzymes. We also demonstrate that the Escherichia coli PplT protein interacts with many phospholipid-synthetic enzymes and deletion of pplT impaired bacterial growth, which supports its potential role in membrane lipid metabolism. PplT domain proteins may be general prokaryotic lipid flippases with critical roles in cellular homeostasis.

microbiology↗

bioRxiv2020

Decoding and blocking the bacterial lipid flippase MprF yields a novel anti-virulence strategy

The pandemic of antibiotic resistance represents a major human health threat demanding new antimicrobial strategies. MprF is the synthase and flippase of the phospholipid lysyl-phosphatidylglycerol that increases virulence and resistance of methicillin-resistant Staphylococcus aureus (MRSA) and other pathogens to cationic host defense peptides and antibiotics. With the aim to design MprF inhibitors that could sensitize MRSA to both, human antimicrobials and antibiotics and support the clearance of staphylococcal infections with minimal selection pressure, we developed MprF-targeting monoclonal antibodies, which bound and blocked the MprF flippase subunit. Antibody M-C7.1 targeted a specific loop in the flippase domain that proved to be exposed at both sides of the bacterial membrane, thereby enhancing the mechanistic understanding into bacterial lipid translocation. M-C7.1 rendered MRSA susceptible to host antimicrobial peptides and antibiotics such as daptomycin. Moreover, it impaired MRSA survival in human phagocytes, which recommends MprF inhibitors for new anti-MRSA approaches. MprF-directed monoclonal antibodies provide a proof of concept for development of precisely targeted anti-virulence approaches, which block bacterial antimicrobial resistance mechanisms.

microbiology↗