ORCID Profile
0000-0003-4764-3639
Current Organisation
The University of Edinburgh
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Publisher: Proceedings of the National Academy of Sciences
Date: 13-04-2015
Abstract: In the natural environment the majority of bacteria live within the confines of a structured social community called a biofilm. The stability of biofilms arises from the extracellular matrix, which consists of proteins, polysaccharides, and extracellular DNA. One of these proteins, BslA, forms a hydrophobic “raincoat” at the surface of the biofilm. We have uncovered the mechanism that enables this protein to function, revealing a structural metamorphosis from a form that is stable in water to a structure that prefers the interface where it self-assembles with nanometer precision to form a robust film. Our findings have wide-ranging implications, from the disruption of harmful bacterial biofilms to the generation of nanoscale materials.
Publisher: Springer Science and Business Media LLC
Date: 17-12-2022
DOI: 10.1038/S41522-022-00361-5
Abstract: A hallmark of microbial biofilms is the self-production of an extracellular molecular matrix that encases the resident cells. The matrix provides protection from the environment, while spatial heterogeneity of gene expression influences the structural morphology and colony spreading dynamics. Bacillus subtilis is a model bacterial system used to uncover the regulatory pathways and key building blocks required for biofilm growth and development. In this work, we report on the emergence of a highly active population of bacteria during the early stages of biofilm formation, facilitated by the extraction of fluid from the underlying agar substrate. We trace the origin of this fluid extraction to the production of poly- γ -glutamic acid (PGA). The flagella-dependent activity develops behind a moving front of fluid that propagates from the boundary of the biofilm towards the interior. The extent of fluid proliferation is controlled by the presence of extracellular polysaccharides (EPS). We also find that PGA production is positively correlated with higher temperatures, resulting in high-temperature mature biofilm morphologies that are distinct from the rugose colony biofilm architecture typically associated with B. subtilis . Although previous reports have suggested that PGA production does not play a major role in biofilm morphology in the undomesticated isolate NCIB 3610, our results suggest that this strain produces distinct biofilm matrices in response to environmental conditions.
Publisher: Wiley
Date: 26-09-2023
DOI: 10.1002/PRO.4736
Abstract: Many proteins that self‐assemble into amyloid and amyloid‐like fibres can adopt erse polymorphic forms. These forms have been observed both in vitro and in vivo and can arise through variations in the steric‐zipper interactions between ꞵ‐sheets, variations in the arrangements between protofilaments, and differences in the number of protofilaments that make up a given fibre class. Different polymorphs arising from the same precursor molecule not only exhibit different levels of toxicity, but importantly can contribute to different disease conditions. However, the factors which contribute to formation of polymorphic forms of amyloid fibrils are not known. In this work, we show that in the presence of 1,2‐dimyristoyl‐sn‐glycero‐3‐phospho‐L‐serine, a highly abundant lipid in the plasma membrane of neurons, the aggregation of α‐synuclein is markedly accelerated and yields a ersity of polymorphic forms under identical experimental conditions. This morphological ersity includes thin and curly fibrils, helical ribbons, twisted ribbons, nanotubes, and flat sheets. Furthermore, the amyloid fibrils formed incorporate lipids into their structures, which corroborates the previous report of the presence of α‐synuclein fibrils with high lipid content in Lewy bodies. Thus, the present study demonstrates that an interface, such as that provided by a lipid membrane, can not only modulate the kinetics of α‐synuclein amyloid aggregation but also plays an important role in the formation of morphological variants by incorporating lipid molecules in the process of amyloid fibril formation. This article is protected by copyright. All rights reserved.
Publisher: American Chemical Society (ACS)
Date: 14-10-2015
DOI: 10.1021/ACS.LANGMUIR.5B02347
Abstract: BslA is an hiphilic protein that forms a highly hydrophobic coat around Bacillus subtilis biofilms, shielding the bacterial community from external aqueous solution. It has a unique structure featuring a distinct partition between hydrophilic and hydrophobic surfaces. This surface property is reminiscent of synthesized Janus colloids. By investigating the behavior of BslA variants at water-cyclohexane interfaces through a set of multiscale simulations informed by experimental data, we show that BslA indeed represents a biological ex le of an ellipsoidal Janus nanoparticle, whose surface interactions are, moreover, readily switchable. BslA contains a local conformational toggle, which controls its global affinity for, and orientation at, water-oil interfaces. This adaptability, together with single-point mutations, enables the fine-tuning of its solvent and interfacial interactions, and suggests that BslA could be a basis for biotechnological applications.
Publisher: Springer Berlin Heidelberg
Date: 2013
Publisher: Proceedings of the National Academy of Sciences
Date: 30-10-2023
Publisher: Cold Spring Harbor Laboratory
Date: 21-12-2020
DOI: 10.1101/2020.12.21.423644
Abstract: A hallmark of microbial biofilms is the self-production of extracellular matrix that encases the cells resident within the community. The matrix provides protection from the environment, while spatial heterogeneity of expression influences the structural morphology and colony spreading dynamics. Bacillus subtilis is a model bacterial system used to uncover the regulatory pathways and key building blocks required for biofilm growth and development. Previous reports have suggested that poly- γ -glutamic acid (PGA) production is suppressed during biofilm formation and does not play a major role in biofilm morphology of the undomesticated isolate NCIB 3610. In this work we report on the observation of multiple travelling fronts that develop during the early stage of B. subtilis colony biofilm formation. We find the emergence of a highly motile population of bacteria that is facilitated by the extraction of fluid from the underlying agar substrate. Motility develops behind a moving front of fluid that propagates from the boundary of the biofilm towards the interior. The extent of proliferation is strongly modulated by the presence of extracellular polysaccharides (EPS). We trace the origin of this moving front of fluid to the production of PGA. We find that PGA production is correlated with higher temperatures, resulting in a mature biofilm morphology that is distinct from the biofilm architecture typically associated with B. subtilis . Our results suggest that B. subtilis NCIB 3610 produces distinct biofilm matrices in response to environmental conditions.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5AN01253H
Abstract: Mass spectrometry shows insulin oligomers [I] n where n ranges from 1-12, and ion mobility analysis reveals ∼60 structurally distinct species across this oligomer distribution. Experimental data trains MD simulations to characterize a persistent prefibrillar protein oligomer that is a dimer enriched in β sheets.
Publisher: The Royal Society
Date: 28-07-2016
Abstract: Intrinsically interfacially active proteins have garnered considerable interest recently owing to their potential use in a range of materials applications. Notably, the fungal hydrophobins are known to form robust and well-organized surface layers with high mechanical strength. Recently, it was shown that the bacterial biofilm protein BslA also forms highly elastic surface layers at interfaces. Here we describe several self-assembled structures formed by BslA, both at interfaces and in bulk solution, over a range of length scales spanning from nanometres to millimetres. First, we observe transiently stable and highly elongated air bubbles formed in agitated BslA s les. We study their behaviour in a range of solution conditions and hypothesize that their dissipation is a consequence of the slow adsorption kinetics of BslA to an air–water interface. Second, we describe elongated tubules formed by BslA interfacial films when shear stresses are applied in both a Langmuir trough and a rheometer. These structures bear a striking resemblance, although much larger in scale, to the elongated air bubbles formed during agitation. Taken together, this knowledge will better inform the conditions and applications of how BslA can be used in the stabilization of multi-phase materials. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Ryan Morris.