scholarly journals Large Scale Discovery of Microbial Fibrillar Adhesins and Identification of Novel Adhesive Domain Families

2021 ◽  
Author(s):  
Vivian Angela Monzon ◽  
Alex Bateman
Keyword(s):  
Biofilm Formation ◽  
Large Scale ◽  
Significant Contribution ◽  
Structural Similarity ◽  
Surface Proteins ◽  
Host Cells ◽  
Bacterial Host ◽  
Cell Surface Proteins ◽  
Host Interactions ◽  
Prediction Approach

Fibrillar adhesins are bacterial cell surface proteins that mediate interactions with host cells during colonisation and with other bacteria during biofilm formation. These proteins are characterised by a stalk that projects the adhesive domain closer to the binding target. Fibrillar adhesins evolve quickly and thus can be difficult to computationally identify, yet they represent an important component for understanding bacterial host interactions. To detect novel fibrillar adhesins we developed a random forest prediction approach based on common characteristics we identified for this protein class. We applied this approach to Firmicute and Actinobacterial proteomes, yielding over 4,000 confidently predicted fibrillar adhesins. To verify the approach we investigated predicted fibrillar adhesins that lacked a known adhesive domain. Based on these proteins, we identified 21 sequence clusters representing potential novel adhesive domains. We used AlphaFold to verify that 14 clusters showed structural similarity to known adhesive domains such as the TED domain. Overall our study has made a significant contribution to the number of known fibrillar adhesins and has enabled us to identify novel adhesive domain families involved in the bacterial pathogenesis.

scholarly journals Cellular Electron Cryo-Tomography to Study Virus-Host Interactions

2020 ◽  
Vol 7 (1) ◽  
pp. 239-262
Author(s):  
Emmanuelle R.J. Quemin ◽  
Emily A. Machala ◽  
Benjamin Vollmer ◽  
Vojtěch Pražák ◽  
Daven Vasishtan ◽  
...  
Keyword(s):  
Viral Entry ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Virus Assembly ◽  
Three Dimensional ◽  
Surface Proteins ◽  
Host Cells ◽  
Phase Plate ◽  
Structural Cell ◽  
Host Interactions

Viruses are obligatory intracellular parasites that reprogram host cells upon infection to produce viral progeny. Here, we review recent structural insights into virus-host interactions in bacteria, archaea, and eukaryotes unveiled by cellular electron cryo-tomography (cryoET). This advanced three-dimensional imaging technique of vitreous samples in near-native state has matured over the past two decades and proven powerful in revealing molecular mechanisms underlying viral replication. Initial studies were restricted to cell peripheries and typically focused on early infection steps, analyzing surface proteins and viral entry. Recent developments including cryo-thinning techniques, phase-plate imaging, and correlative approaches have been instrumental in also targeting rare events inside infected cells. When combined with advances in dedicated image analyses and processing methods, details of virus assembly and egress at (sub)nanometer resolution were uncovered. Altogether, we provide a historical and technical perspective and discuss future directions and impacts of cryoET for integrative structural cell biology analyses of viruses.

scholarly journals Vibriophages Differentially Influence Biofilm Formation by Vibrio anguillarum Strains

2015 ◽  
Vol 81 (13) ◽  
pp. 4489-4497 ◽  
Author(s):  
Demeng Tan ◽  
Amalie Dahl ◽  
Mathias Middelboe
Keyword(s):  
Biofilm Formation ◽  
Vibrio Anguillarum ◽  
Living Cells ◽  
Phage Infection ◽  
Host Cells ◽  
Free Living ◽  
Marine Aquaculture ◽  
Content Type ◽  
Host Interactions ◽  
Biofilm Development

ABSTRACTVibrio anguillarumis an important pathogen in marine aquaculture, responsible for vibriosis. Bacteriophages can potentially be used to control bacterial pathogens; however, successful application of phages requires a detailed understanding of phage-host interactions under both free-living and surface-associated growth conditions. In this study, we exploredin vitrophage-host interactions in two different strains ofV. anguillarum(BA35 and PF430-3) during growth in microcolonies, biofilms, and free-living cells. Two vibriophages, ΦH20 (Siphoviridae) and KVP40 (Myoviridae), had completely different effects on the biofilm development. Addition of phage ΦH20 to strain BA35 showed efficient control of biofilm formation and density of free-living cells. The interactions between BA35 and ΦH20 were thus characterized by a strong phage control of the phage-sensitive population and subsequent selection for phage-resistant mutants. Addition of phage KVP40 to strain PF430-3 resulted in increased biofilm development, especially during the early stage. Subsequent experiments in liquid cultures showed that addition of phage KVP40 stimulated the aggregation of host cells, which protected the cells against phage infection. By the formation of biofilms, strain PF430-3 created spatial refuges that protected the host from phage infection and allowed coexistence between phage-sensitive cells and lytic phage KVP40. Together, the results demonstrate highly variable phage protection mechanisms in two closely relatedV. anguillarumstrains, thus emphasizing the challenges of using phages to control vibriosis in aquaculture and adding to the complex roles of phages as drivers of prokaryotic diversity and population dynamics.

scholarly journals Extracellular DNA, cell surface proteins and c-di-GMP promote biofilm formation in Clostridioides difficile

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lisa F. Dawson ◽  
Johann Peltier ◽  
Catherine L. Hall ◽  
Mark A. Harrison ◽  
Maria Derakhshan ◽  
...  
Keyword(s):  
Cell Surface ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Surface Proteins ◽  
Extracellular Dna ◽  
Cell Surface Proteins ◽  
Secondary Messenger ◽  
Clostridioides Difficile ◽  
Antibiotic Efficacy ◽  
Biofilm Matrix

AbstractClostridioides difficile is the leading cause of nosocomial antibiotic-associated diarrhoea worldwide, yet there is little insight into intestinal tract colonisation and relapse. In many bacterial species, the secondary messenger cyclic-di-GMP mediates switching between planktonic phase, sessile growth and biofilm formation. We demonstrate that c-di-GMP promotes early biofilm formation in C. difficile and that four cell surface proteins contribute to biofilm formation, including two c-di-GMP regulated; CD2831 and CD3246, and two c-di-GMP-independent; CD3392 and CD0183. We demonstrate that C. difficile biofilms are composed of extracellular DNA (eDNA), cell surface and intracellular proteins, which form a protective matrix around C. difficile vegetative cells and spores, as shown by a protective effect against the antibiotic vancomycin. We demonstrate a positive correlation between biofilm biomass, sporulation frequency and eDNA abundance in all five C. difficile lineages. Strains 630 (RT012), CD305 (RT023) and M120 (RT078) contain significantly more eDNA in their biofilm matrix than strains R20291 (RT027) and M68 (RT017). DNase has a profound effect on biofilm integrity, resulting in complete disassembly of the biofilm matrix, inhibition of biofilm formation and reduced spore germination. The addition of exogenous DNase could be exploited in treatment of C. difficile infection and relapse, to improve antibiotic efficacy.

scholarly journals Antiandrogens Target TMPRSS2 and Reduce SARS-CoV-2 Virus Entry in Lung Cells

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A60-A61
Author(s):  
Damien A Leach ◽  
Mohr Andrea ◽  
Ralf Zwacka ◽  
Stathis Giottis ◽  
Laura Yates ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Surface ◽  
Human Lung ◽  
Surface Proteins ◽  
Host Cells ◽  
Mouse Lung ◽  
Lung Cells ◽  
Sequencing Data ◽  
Cell Surface Proteins ◽  
Human Lung Cells

Abstract The SARS-CoV-2 coronavirus is the cause of the COVID-19 pandemic. Entry of the virus into host cells, most destructively lung cells, requires two host cell surface proteins, ACE2 and TMPRSS2, downregulation of which is thus a potential therapeutic approach for COVID-19. Both of these cell surface proteins are steroid regulated: TMPRSS2 is a well-characterised androgen-regulated target in prostate cancer. Analysis of sequencing data shows co-expression of the androgen receptor (AR) and TMPRSS2 in key human lung cell types that are targeted by SARS- CoV-2. We show that treatment with antiandrogens such as enzalutamide (a well-tolerated drug widely used in advanced prostate cancer) significantly reduces TMPRSS2 levels in human lung cells and in vivo in mouse lung. We demonstrate that AR binding in the region of the TMPRSS2 gene differs between lung and prostate, identifying distinct regulatory regions. Together, the data and evidence presented supports clinical trials to assess the efficacy of antiandrogens as a treatment option for COVID-19.

scholarly journals Role of SrtA in Pathogenicity of Staphylococcus lugdunensis

2020 ◽  
Vol 8 (12) ◽  
pp. 1975
Author(s):  
Muzaffar Hussain ◽  
Christian Kohler ◽  
Karsten Becker
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Biofilm Formation ◽  
Surface Proteins ◽  
Transcription Level ◽  
Coagulase Negative Staphylococci ◽  
Staphylococcus Lugdunensis ◽  
Cell Surface Proteins ◽  
Mutant Strains

Among coagulase-negative staphylococci (CoNS), Staphylococcus lugdunensis has a special position as causative agent of aggressive courses of infectious endocarditis (IE) more reminiscent of IEs caused by Staphylococcus aureus than those by CoNS. To initiate colonization and invasion, bacterial cell surface proteins are required; however, only little is known about adhesion of S. lugdunensis to biotic surfaces. Cell surface proteins containing the LPXTG anchor motif are covalently attached to the cell wall by sortases. Here, we report the functionality of Staphylococcus lugdunensis sortase A (SrtA) to link LPXTG substrates to the cell wall. To determine the role of SrtA dependent surface proteins in biofilm formation and binding eukaryotic cells, we generated SrtA-deficient mutants (ΔsrtA). These mutants formed a smaller amount of biofilm and bound less to immobilized fibronectin, fibrinogen, and vitronectin. Furthermore, SrtA absence affected the gene expression of two different adhesins on transcription level. Surprisingly, we found no decreased adherence and invasion in human cell lines, probably caused by the upregulation of further adhesins in ΔsrtA mutant strains. In conclusion, the functionality of S. lugdunensis SrtA in anchoring LPXTG substrates to the cell wall let us define it as the pathogen’s housekeeping sortase.

scholarly journals The dynamics and pH-dependence of Ag43 adhesins’ self-association probed by atomic force spectroscopy

Nanoscale ◽  
2014 ◽  
Vol 6 (21) ◽  
pp. 12665-12681 ◽  
Author(s):  
Adrien Jacquot ◽  
Chizuko Sakamoto ◽  
Angelina Razafitianamarahavo ◽  
Céline Caillet ◽  
Jenny Merlin ◽  
...  
Keyword(s):  
Cell Surface ◽  
Biofilm Formation ◽  
Ph Dependence ◽  
Force Spectroscopy ◽  
Surface Proteins ◽  
Cell Surface Proteins ◽  
Atomic Force Spectroscopy ◽  
Atomic Force ◽  
Self Association

Self-associating auto-transporter (SAAT) adhesins are two-domain cell surface proteins involved in bacteria auto-aggregation and biofilm formation.

scholarly journals Surface Glucan Structures in Aeromonas spp.

Marine Drugs ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. 649
Author(s):  
Elena Mendoza-Barberá ◽  
Susana Merino ◽  
Juan Tomás
Keyword(s):  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Aquatic Environments ◽  
Processed Food ◽  
Opportunistic Pathogens ◽  
Bacterial Host ◽  
Proinflammatory Response ◽  
Host Interactions ◽  
Factors Associated ◽  
Pathogenic Factors

Aeromonas spp. are generally found in aquatic environments, although they have also been isolated from both fresh and processed food. These Gram-negative, rod-shaped bacteria are mostly infective to poikilothermic animals, although they are also considered opportunistic pathogens of both aquatic and terrestrial homeotherms, and some species have been associated with gastrointestinal and extraintestinal septicemic infections in humans. Among the different pathogenic factors associated with virulence, several cell-surface glucans have been shown to contribute to colonization and survival of Aeromonas pathogenic strains, in different hosts. Lipopolysaccharide (LPS), capsule and α-glucan structures, for instance, have been shown to play important roles in bacterial–host interactions related to pathogenesis, such as adherence, biofilm formation, or immune evasion. In addition, glycosylation of both polar and lateral flagella has been shown to be mandatory for flagella production and motility in different Aeromonas strains, and has also been associated with increased bacterial adhesion, biofilm formation, and induction of the host proinflammatory response. The main aspects of these structures are covered in this review.

What do nanometer molecular trajectories tell us about heterogeneous cell surface domaines?

1995 ◽  
Vol 53 ◽  
pp. 786-787
Author(s):  
Watt W. Webb
Keyword(s):  
Cell Surface ◽  
Lipid Membranes ◽  
Surface Proteins ◽  
Protein Diffusion ◽  
Coated Pits ◽  
Cell Surface Proteins ◽  
Membrane Heterogeneity ◽  
Fluorescence Photobleaching Recovery ◽  
Photobleaching Recovery ◽  
Plasma Membrane Heterogeneity

Plasma membrane heterogeneity is implicit in the existence of specialized cell surface organelles which are necessary for cellular function; coated pits, post and pre-synaptic terminals, microvillae, caveolae, tight junctions, focal contacts and endothelial polarization are examples. The persistence of these discrete molecular aggregates depends on localized restraint of the constituent molecules within specific domaines in the cell surface by strong intermolecular bonds and/or anchorage to extended cytoskeleton. The observed plasticity of many of organelles and the dynamical modulation of domaines induced by cellular signaling evidence evanescent intermolecular interactions even in conspicuous aggregates. There is also strong evidence that universal restraints on the mobility of cell surface proteins persist virtually everywhere in cell surfaces, not only in the discrete organelles. Diffusion of cell surface proteins is slowed by several orders of magnitude relative to corresponding protein diffusion coefficients in isolated lipid membranes as has been determined by various ensemble average methods of measurement such as fluorescence photobleaching recovery(FPR).

Insights into the biochemical and functional characterization of sortase E transpeptidase of Corynebacterium glutamicum

2019 ◽  
Vol 476 (24) ◽  
pp. 3835-3847 ◽  
Author(s):  
Aliyath Susmitha ◽  
Kesavan Madhavan Nampoothiri ◽  
Harsha Bajaj
Keyword(s):  
Protein Engineering ◽  
Cell Attachment ◽  
Functional Characterization ◽  
Protein Structures ◽  
Structural Similarity ◽  
Surface Proteins ◽  
Sortase A ◽  
Peptide Cleavage ◽  
New Findings

Most Gram-positive bacteria contain a membrane-bound transpeptidase known as sortase which covalently incorporates the surface proteins on to the cell wall. The sortase-displayed protein structures are involved in cell attachment, nutrient uptake and aerial hyphae formation. Among the six classes of sortase (A–F), sortase A of S. aureus is the well-characterized housekeeping enzyme considered as an ideal drug target and a valuable biochemical reagent for protein engineering. Similar to SrtA, class E sortase in GC rich bacteria plays a housekeeping role which is not studied extensively. However, C. glutamicum ATCC 13032, an industrially important organism known for amino acid production, carries a single putative sortase (NCgl2838) gene but neither in vitro peptide cleavage activity nor biochemical characterizations have been investigated. Here, we identified that the gene is having a sortase activity and analyzed its structural similarity with Cd-SrtF. The purified enzyme showed a greater affinity toward LAXTG substrate with a calculated KM of 12 ± 1 µM, one of the highest affinities reported for this class of enzyme. Moreover, site-directed mutation studies were carried to ascertain the structure functional relationship of Cg-SrtE and all these are new findings which will enable us to perceive exciting protein engineering applications with this class of enzyme from a non-pathogenic microbe.

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