scholarly journals Dual functionality of the TasA amyloid protein inBacillusphysiology and fitness on the phylloplane

2019 ◽  
Author(s):  
Jesús Cámara-Almirón ◽  
Yurena Navarro ◽  
M. Concepción Magno-Pérez-Bryan ◽  
Carlos Molina-Santiago ◽  
John R. Pearson ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Membrane Dynamics ◽  
Fiber Formation ◽  
Membrane Microdomains ◽  
Amyloid Protein ◽  
Functional Amyloid ◽  
Functional Membrane ◽  
Bacterial Fitness ◽  
Amyloid Fiber Formation ◽  
The Individual

AbstractBacteria can form biofilms that consist of multicellular communities embedded in an extracellular matrix (ECM). Previous studies have demonstrated that genetic pathways involved in biofilm formation are activated under a variety of environmental conditions to enhance bacterial fitness; however, the functions of the individual ECM components are still poorly understood. InBacillus subtilis, the main protein component of the ECM is the functional amyloid TasA. In this study, we demonstrate that beyond their well-known defect in biofilm formation,ΔtasAcells also exhibit a range of cytological symptoms indicative of excessive cellular stress, including DNA damage accumulation, changes in membrane potential, higher susceptibility to oxidative stress, and alterations in membrane dynamics. Collectively, these events can lead to increased programmed cell death in the colony. We show that these major physiological changes inΔtasAcells are likely independent of the structural role of TasA during amyloid fiber formation in the ECM. The presence of TasA in cellular membranes, which would place it in proximity to functional membrane microdomains, and mislocalization of the flotillin-like protein FloT inΔtasAcells, led us to propose a role for TasA in the stabilization of membrane dynamics as cells enter stationary phase. We found that these alterations caused by the absence of TasA impair the survival, colonization and competition ofBacilluscells on the phylloplane. Taken together, our results allow the separation of two complementary roles of this functional amyloid protein: i) structural functions during ECM assembly and interactions with plants, and ii) a physiological function in which TasA, via its localization to the cell membrane, stabilizes membrane dynamics and supports more effective cellular adaptation to environmental cues.

scholarly journals The biofilm adhesion protein Aap from Staphylococcus epidermidis forms zinc-dependent amyloid fibers

2020 ◽  
Vol 295 (14) ◽  
pp. 4411-4427 ◽  
Author(s):  
Alexander E. Yarawsky ◽  
Stefanie L. Johns ◽  
Peter Schuck ◽  
Andrew B. Herr
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Fiber Formation ◽  
Amyloid Fibers ◽  
Adhesion Protein ◽  
Amyloid Fiber Formation ◽  
Necessary And Sufficient ◽  
Hospital Acquired ◽  
Amyloid Assembly ◽  
Accumulation Associated Protein

The skin-colonizing commensal bacterium Staphylococcus epidermidis is a leading cause of hospital-acquired and device-related infections. Its pathogenicity in humans is largely due to its propensity to form biofilms, surface-adherent bacterial accumulations that are remarkably resistant to chemical and physical stresses. Accumulation-associated protein (Aap) from S. epidermidis has been shown to be necessary and sufficient for mature biofilm formation and catheter infection. Aap contains up to 17 tandem B-repeat domains, capable of zinc-dependent assembly into twisted, rope-like intercellular filaments in the biofilm. Using microscopic and biophysical techniques, we show here that Aap B-repeat constructs assemble further into zinc-dependent functional amyloid fibers. We observed such amyloid fibers by confocal microscopy during both early and late stages of S. epidermidis biofilm formation, and we confirmed that extracellular fibrils from these biofilms contain Aap. Unlike what has been observed for amyloidogenic biofilm proteins from other bacteria, which typically use chaperones or initiator proteins to initiate amyloid assembly, our findings indicate that Aap from S. epidermidis requires Zn2+ as a catalyst that drives amyloid fiber formation, similar to many mammalian amyloid-forming proteins that require metals for assembly. This work provides detailed insights into S. epidermidis biofilm formation and architecture that improve our understanding of persistent staphylococcal infections.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

scholarly journals Chaperones mainly suppress primary nucleation during formation of functional amyloid required for bacterial biofilm formation

2022 ◽  
Author(s):  
Madhu Nagaraj ◽  
Zahra Najarzadeh ◽  
Jonathan Pansieri ◽  
Ludmilla A. Morozova-Roche ◽  
Henrik Biverstål ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Functional Amyloid ◽  
E Coli ◽  
Primary Nucleation ◽  
Functional Amyloids

Unlike misfolding in neurodegenerative diseases, aggregation of functional amyloids involved in bacterial biofilm, e.g. CsgA (E. coli) and FapC (Pseudomonas), is carefully regulated. However, it is unclear whether functional aggregation...

Bacterial Model Membranes Reshape Fibrillation of a Functional Amyloid Protein

Biochemistry ◽  
2018 ◽  
Vol 57 (35) ◽  
pp. 5230-5238 ◽  
Author(s):  
Ravit Malishev ◽  
Razan Abbasi ◽  
Raz Jelinek ◽  
Liraz Chai
Keyword(s):  
Model Membranes ◽  
Amyloid Protein ◽  
Functional Amyloid ◽  
Bacterial Model

Colloidal-like aggregation of a functional amyloid protein

2020 ◽  
Vol 22 (40) ◽  
pp. 23286-23294
Author(s):  
David N. Azulay ◽  
Mnar Ghrayeb ◽  
Ilanit Bensimhon Ktorza ◽  
Ido Nir ◽  
Rinad Nasser ◽  
...  
Keyword(s):  
Protein Aggregates ◽  
Amyloid Protein ◽  
Functional Amyloid ◽  
Acidic Conditions

TasA, a bacterial functional amyloid protein, aggregates in a colloidal – like mechanism upon exposure to acidic conditions.

scholarly journals Quorum-Sensing Mutations Affect Attachment and Stability of Burkholderia cenocepacia Biofilms

2005 ◽  
Vol 71 (9) ◽  
pp. 5208-5218 ◽  
Author(s):  
Kerry L. Tomlin ◽  
Rebecca J. Malott ◽  
Gordon Ramage ◽  
Douglas G. Storey ◽  
Pamela A. Sokol ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Cell Mass ◽  
Sodium Dodecyl ◽  
Burkholderia Cenocepacia ◽  
Structural Defects ◽  
Expression Vectors ◽  
Structural Development ◽  
The Individual

ABSTRACT Biofilm formation in Burkholderia cenocepacia has been shown to rely in part on acylhomoserine lactone-based quorum sensing. For many other bacterial species, it appears that both the initial adherence and the later stages of biofilm maturation are affected when quorum sensing pathways are inhibited. In this study, we examined the effects of mutations in the cepIR and cciIR quorum-sensing systems of Burkholderia cenocepacia K56-2 with respect to biofilm attachment and antibiotic resistance. We also examined the role of the cepIR system in biofilm stability and structural development. Using the high-throughput MBEC assay system to produce multiple equivalent biofilms, the biomasses of both the cepI and cepR mutant biofilms, measured by crystal violet staining, were less than half of the value observed for the wild-type strain. Attachment was partially restored upon providing functional gene copies via multicopy expression vectors. Surprisingly, neither the cciI mutant nor the double cciI cepI mutant was deficient in attachment, and restoration of the cciI gene resulted in less attachment than for the mutants. Meanwhile, the cciR mutant did show a significant reduction in attachment, as did the cciR cepIR mutant. While there was no change in antibiotic susceptibility with the individual cepIR and cciIR mutants, the cepI cciI mutant biofilms were more sensitive to ciprofloxacin. A significant increase in sensitivity to removal by sodium dodecyl sulfate was seen for the cepI and cepR mutants. Flow cell analysis of the individual cepIR mutant biofilms indicated that they were both structurally and temporally impaired in attachment and development. These results suggest that biofilm structural defects might be present in quorum-sensing mutants of B. cenocepacia that affect the stability and resistance of the adherent cell mass, providing a basis for future studies to design preventative measures against biofilm formation in this species, an important lung pathogen of cystic fibrosis patients.

scholarly journals Epigenetic profiling of Italian patients identified methylation sites associated with hereditary transthyretin amyloidosis

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Antonella De Lillo ◽  
Gita A. Pathak ◽  
Flavio De Angelis ◽  
Marco Di Girolamo ◽  
Marco Luigetti ◽  
...  
Keyword(s):  
Amyloid Beta ◽  
Molecular Mechanisms ◽  
Regression Coefficient ◽  
Phenotypic Variability ◽  
Interaction Network ◽  
Fiber Formation ◽  
Transthyretin Amyloidosis ◽  
Beta Secretase ◽  
Life Threatening ◽  
Amyloid Fiber Formation

AbstractHereditary transthyretin (TTR) amyloidosis (hATTR) is a rare life-threatening disorder caused by amyloidogenic coding mutations located in TTR gene. To understand the high phenotypic variability observed among carriers of TTR disease-causing mutations, we conducted an epigenome-wide association study (EWAS) assessing more than 700,000 methylation sites and testing epigenetic difference of TTR coding mutation carriers vs. non-carriers. We observed a significant methylation change at cg09097335 site located in Beta-secretase 2 (BACE2) gene (standardized regression coefficient = −0.60, p = 6.26 × 10–8). This gene is involved in a protein interaction network enriched for biological processes and molecular pathways related to amyloid-beta metabolism (Gene Ontology: 0050435, q = 0.007), amyloid fiber formation (Reactome HSA-977225, q = 0.008), and Alzheimer’s disease (KEGG hsa05010, q = 2.2 × 10–4). Additionally, TTR and BACE2 share APP (amyloid-beta precursor protein) as a validated protein interactor. Within TTR gene region, we observed that Val30Met disrupts a methylation site, cg13139646, causing a drastic hypomethylation in carriers of this amyloidogenic mutation (standardized regression coefficient = −2.18, p = 3.34 × 10–11). Cg13139646 showed co-methylation with cg19203115 (Pearson’s r2 = 0.32), which showed significant epigenetic differences between symptomatic and asymptomatic carriers of amyloidogenic mutations (standardized regression coefficient = −0.56, p = 8.6 × 10–4). In conclusion, we provide novel insights related to the molecular mechanisms involved in the complex heterogeneity of hATTR, highlighting the role of epigenetic regulation in this rare disorder.

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