The cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. The cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. All of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. Two basic mechanisms, cell wall sorting and targeting, have been identified. Cell well sorting is the covalent attachment of surface proteins to the peptidoglycan via a C-terminal sorting signal that contains a consensus LPXTG sequence. More than 100 proteins that possess cell wall-sorting signals, including the M proteins of Streptococcus pyogenes, protein A of Staphylococcus aureus, and several internalins of Listeria monocytogenes, have been identified. Cell wall targeting involves the noncovalent attachment of proteins to the cell surface via specialized binding domains. Several of these wall-binding domains appear to interact with secondary wall polymers that are associated with the peptidoglycan, for example teichoic acids and polysaccharides. Proteins that are targeted to the cell surface include muralytic enzymes such as autolysins, lysostaphin, and phage lytic enzymes. Other examples for targeted proteins are the surface S-layer proteins of bacilli and clostridia, as well as virulence factors required for the pathogenesis of L. monocytogenes (internalin B) and Streptococcus pneumoniae (PspA) infections. In this review we describe the mechanisms for both sorting and targeting of proteins to the envelope of gram-positive bacteria and review the functions of known surface proteins.

Surface Proteins of Gram-Positive Bacteria and Mechanisms of Their Targeting to the Cell Wall Envelope

Analysis of Sp1 in vivo reveals mutiple transcriptional domains, including a novel glutamine-rich activation motif

Rad51 protein involved in repair and recombination in S. cerevisiae is a RecA-like protein

Design and functionalization strategies for multifunctional nanocarriers (e.g., nanoparticles, micelles, polymersomes) based on biodegradable/biocompatible polymers intended to be employed for active targeting and drug delivery are reviewed. This review will focus on the nature of the polymers involved in the preparation of targeted nanocarriers, the synthesis methods to achieve the desired macromolecular architecture, the selected coupling strategy, the choice of the homing molecules (vitamins, hormones, peptides, proteins, etc.), as well as the various strategies to display them at the surface of nanocarriers. The resulting morphologies and the main colloidal features will be given as well as an overview of the biological activities, with a special focus on the main in vivo achievements.

Design, functionalization strategies and biomedical applications of targeted biodegradable/biocompatible polymer-based nanocarriers for drug delivery

The production of enzymes capable of degrading the cell walls of invading phytopathogenic fungi is an important component of the defense response of plants. The timing of this natural host defense mechanism was modified to produce fungal-resistant plants. Transgenic tobacco seedlings constitutively expressing a bean chitinase gene under control of the cauliflower mosaic virus 35S promoter showed an increased ability to survive in soil infested with the fungal pathogen Rhizoctonia solani and delayed development of disease symptoms.

https://science.sciencemag.org/content/sci/254/5035/1194.full.pdf

Transgenic Plants with Enhanced Resistance to the Fungal Pathogen Rhizoctonia solani

A rapid sensitive method for detection of alkaline phosphatase conjugated anti antibody on western blots

Effective oral delivery of insulin in animal models using vitamin B12-coated dextran nanoparticles.

A number of group B streptococcal strains of various serotypes, Ia, Ib, Ic, II, and III were examined for their ability to bind human IgG and IgA. No strains of group B streptococci were found to bind IgG, but many strains possessing the Ibc protein antigen(s) were found to bind a significant amount of IgA. The extent of IgA binding correlated with the amount of a 130,000 mol wt, detergent-extractable protein, and reactivity with the Ic typing sera. Using nitrocellulose blots, it was found that the 130,000 mol wt protein bound human IgA. A method was developed to purify the protein while retaining its ability to bind human IgA. Using solid phase radioimmunoassays, it was determined that the protein bound to the Fc region of monomeric or polymeric IgA and that it failed to bind IgM or any IgG isotype.

https://rupress.org/jem/article-pdf/160/5/1467/1094886/1467.pdf

A SURFACE RECEPTOR SPECIFIC FOR HUMAN IgA ON GROUP B STREPTOCOCCI POSSESSING THE Ibc PROTEIN ANTIGEN

Oral vaccine delivery.

The protein antigens of prototypes of five types of group B streptococcal strains were extracted with HCl or Triton X-100, separated by sodium dodecyl sulfate polyacrylamide electrophoresis, transferred to nitrocellulose, and examined by immunochemical staining. The Ibc proteins are shown to consist of at least two distinct protein antigens and their breakdown products. One antigen, the "beta" antigen, exists primarily as a 130,000 mol wt protein that is also able to bind human IgA. The "alpha" antigen, which has no known function, appears as a number of proteins of various molecular weights from 20,000 to 120,000. Another set of antigens, the R protein antigens of type III strains, has been identified as a group of acid-labile proteins varying in molecular weight from 100,000 to 130,000. In addition, two previously undescribed antigens have been found that are common to all five group B types.

/pdf/identification-of-protein-antigens-of-group-b-streptococci-27w87s10te.pdf

G J Russell-Jones

Papers

A rapid sensitive method for detection of alkaline phosphatase conjugated anti antibody on western blots

Effective oral delivery of insulin in animal models using vitamin B12-coated dextran nanoparticles.

A SURFACE RECEPTOR SPECIFIC FOR HUMAN IgA ON GROUP B STREPTOCOCCI POSSESSING THE Ibc PROTEIN ANTIGEN

Oral vaccine delivery.

Identification of protein antigens of group B streptococci, with special reference to the Ibc antigens.