A Novel MSCRAMM Subfamily in Coagulase Negative Staphylococcal Species

Coagulase negative staphylococci are important opportunistic pathogens. Staphylococcus epidermidis, a coagulase negative staphylococcus, is the third leading cause of nosocomial infections in the US. Surface proteins like Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are major virulence factors of pathogenic gram positive bacteria. Here, we identified a new chimeric protein; SesJ in S. epidermidis, which represents a prototype of a new subfamily of MSCRAMMs. Structural predictions show that SesJ has structural features characteristic of a MSCRAMM along with a N-Terminal repeat region and an Aspartic acid containing repeat region, features that have not been previously observed in staphylococcal MSCRAMMs but have been found in other surface proteins from gram positive bacteria. We identified and analyzed structural homologs of SesJ in three other coagulase negative staphylococci. These homologs of SesJ have an identical structural organization but varying sequence identities within the domains. Using flow cytometry, we also show that SesJ is expressed constitutively on the surface of a representative S. epidermidis strain, from early exponential to stationary growth phase. Thus SesJ is positioned to interact with protein targets in the environment and play a role in S. epidermidis virulence

A “dock, lock, and latch” Structural Model for a Staphylococcal Adhesin Binding to Fibrinogen

AbstractGram-positive pathogens such as staphylococci contain multiple cell wall-anchored proteins that serve as an interface between the microbe and its environment. Some of these proteins act as adhesins and mediate bacterial attachment to host tissues. SdrG is a cell wall-anchored adhesin from Staphylococcus epidermidis that binds to the Bβ chain of human fibrinogen (Fg) and is necessary and sufficient for bacterial attachment to Fg-coated biomaterials. Here, we present the crystal structures of the ligand binding region of SdrG as an apoprotein and in complex with a synthetic peptide analogous to its binding site in Fg. Analysis of the crystal structures, along with mutational studies of both the protein and of the peptide, reveals that SdrG binds to its ligand with a dynamic “dock, lock, and latch” mechanism. We propose that this mechanism represents a general mode of ligand binding for structurally related cell wall-anchored proteins of gram-positive bacteria

There is more to accommodation of the eye than simply minimizing retinal blur.

Eyes of children and young adults change their optical power to focus nearby objects at the retina. But does accommodation function by trial and error to minimize blur and maximize contrast as is generally accepted? Three experiments in monocular and monochromatic vision were performed under two conditions while aberrations were being corrected. In the first condition, feedback was available to the eye from both optical vergence and optical blur. In the second, feedback was only available from target blur. Accommodation was less precise for the second condition, suggesting that it is more than a trial-and-error function. Optical vergence itself seems to be an important cue for accommodation

Host-specialized fibrinogen-binding by a bacterial surface protein promotes biofilm formation and innate immune evasion

Fibrinogen is an essential part of the blood coagulation cascade and a major component of the extracellular matrix in mammals. The interface between fibrinogen and bacterial pathogens is an important determinant of the outcome of infection. Here, we demonstrate that a canine host-restricted skin pathogen, Staphylococcus pseudintermedius, produces a cell wall-associated protein (SpsL) that has evolved the capacity for high strength binding to canine fibrinogen, with reduced binding to fibrinogen of other mammalian species including humans. Binding occurs via the surface-expressed N2N3 subdomains, of the SpsL A-domain, to multiple sites in the fibrinogen α-chain C-domain by a mechanism analogous to the classical dock, lock, and latch binding model. Host-specific binding is dependent on a tandem repeat region of the fibrinogen α-chain, a region highly divergent between mammals. Of note, we discovered that the tandem repeat region is also polymorphic in different canine breeds suggesting a potential influence on canine host susceptibility to S. pseudintermedius infection. Importantly, the strong host-specific fibrinogen-binding interaction of SpsL to canine fibrinogen is essential for bacterial aggregation and biofilm formation, and promotes resistance to neutrophil phagocytosis, suggesting a key role for the interaction during pathogenesis. Taken together, we have dissected a bacterial surface protein-ligand interaction resulting from the co-evolution of host and pathogen that promotes host-specific innate immune evasion and may contribute to its host-restricted ecology

Pelko ja ahdistus : Nationalistinen ja rasistinen fantasian politiikka

Crises have become a new normality. This normality is turned into grounds for the politics of fear. The hegemonic principle of the politics of fear is security. This politics, which invents objects of fear, is intimately linked to the nationalist identity politics shaped by a particular nationalist essence. Racism is an elemental part of the nationalist identity politics. In the text, racism is considered in relation to, on the one hand, fear and anxiety and, on the other hand, the imaginary and symbolic orders and the structure of fantasy. This analysis shows how xenophobic images, nationalist signifiers and racist fantasies create the vicious circles of fear and hate that gives justification for the nationalist identity politics that raises security as the hegemonic organizing principle. To counter the nationalist identity politics, the nationalist and racist fantasy must be traversed. Therefore, an anti-racist politics cannot be based on any pre-given identity. It takes place only as emancipatory events that confront the racists and nationalist fantasy.Peer reviewe

Gonococcal vaccines: Public health value and preferred product characteristics; report of a WHO global stakeholder consultation, January 2019.

Renewed interest in developing vaccines against Neisseria gonorrhoeae has been sparked by the increasing threat of gonococcal antimicrobial resistance (AMR) and growing optimism that gonococcal vaccines are biologically feasible. Evidence suggests serogroup B Neisseria meningitidis vaccines might provide some cross-protection against N. gonorrhoeae, and new gonococcal vaccine candidates based on several approaches are currently in preclinical development. To further stimulate investment and accelerate development of gonococcal vaccines, greater understanding is needed regarding the overall value that gonococcal vaccines might have in addressing public health and societal goals in low-, middle-, and high-income country contexts and how future gonococcal vaccines might be accepted and used, if available. In January 2019, the World Health Organization (WHO) convened a multidisciplinary international group of experts to lay the groundwork for understanding the potential health, economic, and societal value of gonococcal vaccines and their likely acceptance and use, and for developing gonococcal vaccine preferred product characteristics (PPCs). WHO PPCs describe preferences for vaccine attributes that would help optimize vaccine value and use in meeting the global public health need. This paper describes the main discussion points and conclusions from the January 2019 meeting of experts. Participants emphasized the need for vaccines to control N. gonorrhoeae infections with the ultimate goals of preventing adverse sexual and reproductive health outcomes (e.g., infertility) and reducing the impact of gonococcal AMR. Meeting participants also discussed important PPC considerations (e.g., vaccine indications, target populations, and potential immunization strategies) and highlighted crucial research and data needs for guiding the value assessment and PPCs for gonococcal vaccines and advancing gonococcal vaccine development

Decorin binding protein compositions

Disclosed are the dbp gene and dbp-derived nucleic acid segments from Borrelia burgdorferi, the etiological agent of Lyme disease, and DNA segments encoding dbp from related borrelias. Also disclosed are decorin binding protein compositions and methods of use. The DBP protein and antigenic epitopes derived therefrom are contemplated for use in the treatment of pathological Borrelia infections, and in particular, for use in the prevention of bacterial adhesion to decorin. DNA segments encoding these proteins and anti-(decorin binding protein) antibodies will also be of use in various screening, diagnostic and therapeutic applications including active and passive immunization and methods for the prevention of Borrelia colonization in an animal. These DNA segments and the peptides derived therefrom are contemplated for use in the preparation of vaccines and, also, for use as carrier proteins in vaccine formulations, and in the formulation of compositions for use in the prevention of Lyme disease.U

Decorin binding protein compositions

Disclosed are the dbp gene and dbp-derived nucleic acid segments from Borrelia burgdorferi, the etiological agent of Lyme disease, and DNA segments encoding dbp from related borrelias. Also disclosed are decorin binding protein compositions and methods of use. The DBP protein and antigenic epitopes derived therefrom are contemplated for use in the treatment of pathological Borrelia infections, and in particular, for use in the prevention of bacterial adhesion to decorin. DNA segments encoding these proteins and anti-(decorin binding protein) antibodies will also be of use in various screening, diagnostic and therapeutic applications including active and passive immunization and methods for the prevention of Borrelia colonization in an animal. These DNA segments and the peptides derived therefrom are contemplated for use in the preparation of vaccines and, also, for use as carrier proteins in vaccine formulations, and in the formulation of compositions for use in the prevention of Lyme disease.U

Decorin binding protein compositions and methods of use

Disclosed are the dbp gene and dbp-derived nucleic acid segments from Borrelia burgdorferi, the etiological agent of Lyme disease, and DNA segments encoding dbp from related borrelias. Also disclosed are decorin binding protein compositions and methods of use. The DBP protein and antigenic epitopes derived therefrom are contemplated for use in the treatment of pathological Borrelia infections, and in particular, for use in the prevention of bacterial adhesion to decorin. DNA segments encoding these proteins and anti-(decorin binding protein) antibodies will also be of use in various screening, diagnostic and therapeutic applications including active and passive immunization and methods for the prevention of Borrelia colonization in an animal. These DNA segments and the peptides derived therefrom are contemplated for use in the preparation of vaccines and, also, for use as carrier proteins in vaccine formulations, and in the formulation of compositions for use in the prevention of Lyme disease.U