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Pathogenicity and Virulence
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
The observation that some microbes affect particular hosts and selectively attach only to certain cells within these hosts suggests tha t adherence is a specific process. There are indeed distinct structural moieties on the surfaces of microbes, termed adhesins, which mediate adherence by binding specifically, much like a key in a lock, to receptors on the host cell surface. Fimbriae, outer membrane proteins, and the lipopolysaccharide (LPS) of Gram-negative bacteria, fibrillae on streptococci, flagellae, capsules, and even exotoxins may function in adherence.
Disease Prediction and Drug Development
Published in Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam, Introduction to Computational Health Informatics, 2019
Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam
The proteins characterized as common virulence-factors include: 1) adhesins – bacterial cell-surface proteins that allow the pathogen to get attached to host cells; 2) toxins – an antigenic substance produced by the pathogens toxic to the human-cells; 3) invasins – bacterial-cell proteins that penetrate and damage host human-cell and are responsible for the spread of pathogens; 4) secretion systems – protein complexes that secrete virulence-factors to invade the host cells and 5) iron uptake system – proteins involved in taking iron from the environment.
Engineering Escherichia coli to Combat Cancer
Published in Ananda M. Chakrabarty, Arsénio M. Fialho, Microbial Infections and Cancer Therapy, 2019
Carlos Piñero-Lambea, David Ruano-Gallego, Gustavo Bodelón, Beatriz Álvarez, Luis Ángel Fernández
A high variety of proteins involved in tissue and surface adhesion (referred to as adhesins) are encoded in the E. coli genome, highlighting the importance that host and surface attachment has for this microorganism [56–58]. Adhesins can be subdivided into two major classes: (i) fimbrial adhesins, which constitute a group of filamentous appendages associated to the bacterial surface, and (ii) non-fimbrial adhesins, which are surface-associated proteins, mostly nonmultimeric, that anchor in the bacterial outer membrane (OM). Frequently, fimbrial-and non-fimbrial adhesins of E. coli contain immunoglobulin (Ig)-like domains in their structure for recognition of host tissues/cells [59].
Helicobacter pylori employs a general protein glycosylation system for the modification of outer membrane adhesins
Published in Gut Microbes, 2022
Kai-Wen Teng, Kai-Siang Hsieh, Ji-Shiuan Hung, Chun-Jen Wang, En-Chi Liao, Pei-Chun Chen, Ying-Hsuan Lin, Deng-Chyang Wu, Chun-Hung Lin, Wen-Ching Wang, Hong-Lin Chan, Shau-Ku Huang, Mou-Chieh Kao
Here, our results show that the key adhesins AlpA, AlpB, BabA, and BabB are modified by glycans. The disruption of several genes involved in glycan biosynthesis and translocation of LPS O-antigen alter the electrophoretic mobility of the tested adhesins, suggesting that enzymes encoded by these genes are not only involved in LPS biosynthesis but also shared with a general protein glycosylation system identified in the present study. Disruption of adhesin glycosylation leads to significant reductions in adhesin resistance to proteases, protein stability, and adhesin binding ability. In this study, protein glycosylation was confirmed to be crucial for adhesin function. Since the disruption of protein glycosylation, as shown here for key adhesins, induces comprehensive defects in H. pylori, the enzymes involved in the protein glycosylation pathway may be suitable drug targets for preventing or treating H. pylori infection.
Reverse engineering approach: a step towards a new era of vaccinology with special reference to Salmonella
Published in Expert Review of Vaccines, 2022
Shania Vij, Reena Thakur, Praveen Rishi
A 27kDa putative outer membrane adhesion protein (T2544) of S. Typhi identified by Ghosh et al. [126] has been proposed as an ideal vaccine candidate. The study used computational approaches coupled with in vitro and in vivo experiments to identify hitherto undescribed pathogenicity-associated molecules of S. Typhi. Out of all predicted proteins, the three most hydrophobic putative adhesin proteins were selected and their role in adhesion was studied by generating isogenic mutants in S. Typhi Ty2 background (deletion of t2544, t1831, and t2769 genes). Adhesion to human cell lines was significantly impaired for only one mutant Ty2Δt2544, which was selected for further study. The T2544 was shown to play a role in bacterial adhesion through high-affinity binding to laminin, which was further validated using mutant bacteria in mice. Protein was shown to be immunogenic and protective in an animal model as well as shown to induce the generation of antibodies in humans. Although it has been believed that the vaccine efficacy of protein adhesins has been shown to be largely compromised by antigenic variability, this report altogether indicates the immunoprophylactic potential of T2544 adhesin with wide distribution and conservation in the clinical isolates of different Salmonella serovars thus making it an ideal vaccine candidate.
Anthrax prevention through vaccine and post-exposure therapy
Published in Expert Opinion on Biological Therapy, 2020
Manish Manish, Shashikala Verma, Divya Kandari, Parul Kulshreshtha, Samer Singh, Rakesh Bhatnagar
Colonization of hosts requires the presence of adhesins on the bacterial surface to facilitate its adherence to the host cells and subsequent internalization to deliver toxins and virulence factors. The most expressed adhesins in bacteria are surface lectins which also act as virulence factors. Blocking of the lectins has been suggested as a strategy for anti-adhesion therapy against bacterial pathogens. In anti-adhesion therapy, the association of bacteria to host cells is prevented. It reduces the chances of colonization and hence the disease [201]. Several targets or strategies may be pursued to compromise the bacterial adhesion, e.g., coating of target substrate or surface anchor modification, adhesin biosynthesis, glycosylation of target substrate, use of anti-adhesin antibodies and adhesin analogs to block adhesin binding, etc. The toxin-antitoxin systems of B. anthracis and quorum sensing are some of the other poorly explored areas that have the potential to revolutionize the ways to slow down the pace of disease progression.