1
|
Alodaini D, Hernandez-Rocamora V, Boelter G, Ma X, Alao MB, Doherty HM, Bryant JA, Moynihan P, Moradigaravand D, Glinkowska M, Vollmer W, Banzhaf M. Reduced peptidoglycan synthesis capacity impairs growth of E. coli at high salt concentration. mBio 2024; 15:e0032524. [PMID: 38426748 PMCID: PMC11005333 DOI: 10.1128/mbio.00325-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 02/13/2024] [Indexed: 03/02/2024] Open
Abstract
Gram-negative bacteria have a thin peptidoglycan layer between the cytoplasmic and outer membranes protecting the cell from osmotic challenges. Hydrolases of this structure are needed to cleave bonds to allow the newly synthesized peptidoglycan strands to be inserted by synthases. These enzymes need to be tightly regulated and their activities coordinated to prevent cell lysis. To better understand this process in Escherichia coli, we probed the genetic interactions of mrcA (encodes PBP1A) and mrcB (encodes PBP1B) with genes encoding peptidoglycan amidases and endopeptidases in envelope stress conditions. Our extensive genetic interaction network analysis revealed relatively few combinations of hydrolase gene deletions with reduced fitness in the absence of PBP1A or PBP1B, showing that none of the amidases or endopeptidases is strictly required for the functioning of one of the class A PBPs. This illustrates the robustness of the peptidoglycan growth mechanism. However, we discovered that the fitness of ∆mrcB cells is significantly reduced under high salt stress and in vitro activity assays suggest that this phenotype is caused by a reduced peptidoglycan synthesis activity of PBP1A at high salt concentration.IMPORTANCEEscherichia coli and many other bacteria have a surprisingly high number of peptidoglycan hydrolases. These enzymes function in concert with synthases to facilitate the expansion of the peptidoglycan sacculus under a range of growth and stress conditions. The synthases PBP1A and PBP1B both contribute to peptidoglycan expansion during cell division and growth. Our genetic interaction analysis revealed that these two penicillin-binding proteins (PBPs) do not need specific amidases, endopeptidases, or lytic transglycosylases for function. We show that PBP1A and PBP1B do not work equally well when cells encounter high salt stress and demonstrate that PBP1A alone cannot provide sufficient PG synthesis activity under this condition. These results show how the two class A PBPs and peptidoglycan hydrolases govern cell envelope integrity in E. coli in response to environmental challenges and particularly highlight the importance of PBP1B in maintaining cell fitness under high salt conditions.
Collapse
Affiliation(s)
- Dema Alodaini
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Victor Hernandez-Rocamora
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gabriela Boelter
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Xuyu Ma
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Micheal B. Alao
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Hannah M. Doherty
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Jack A. Bryant
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Patrick Moynihan
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Danesh Moradigaravand
- KAUST Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Makkah, Saudi Arabia
- Laboratory for Infectious Disease Epidemiology, KAUST Smart-Health Initiative and Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Makkah, Saudi Arabia
| | - Monika Glinkowska
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Waldemar Vollmer
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Manuel Banzhaf
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| |
Collapse
|
2
|
Karbowniczek JE, Berniak K, Knapczyk-Korczak J, Williams G, Bryant JA, Nikoi ND, Banzhaf M, de Cogan F, Stachewicz U. Strategies of nanoparticles integration in polymer fibers to achieve antibacterial effect and enhance cell proliferation with collagen production in tissue engineering scaffolds. J Colloid Interface Sci 2023; 650:1371-1381. [PMID: 37480652 DOI: 10.1016/j.jcis.2023.07.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/30/2023] [Accepted: 07/11/2023] [Indexed: 07/24/2023]
Abstract
Current design strategies for biomedical tissue scaffolds are focused on multifunctionality to provide beneficial microenvironments to support tissue growth. We have developed a simple yet effective approach to create core-shell fibers of poly(3-hydroxybuty-rate-co-3-hydroxyvalerate) (PHBV), which are homogenously covered with titanium dioxide (TiO2) nanoparticles. Unlike the blend process, co-axial electrospinning enabled the uniform distribution of nanoparticles without the formation of large aggregates. We observed 5 orders of magnitude reduction in Escherichia coli survival after contact with electrospun scaffolds compared to the non-material control. In addition, our hybrid cores-shell structure supported significantly higher osteoblast proliferation after 7 days of cell culture and profound generation of 3D networked collagen fibers after 14 days. The organic-inorganic composite scaffold produced in this study demonstrates a unique combination of antibacterial properties and increased bone regeneration properties. In summary, the multifunctionality of the presented core-shell cPHBV+sTiO2 scaffolds shows great promise for biomedical applications.
Collapse
Affiliation(s)
- J E Karbowniczek
- AGH University of Krakow, Faculty of Metals Engineering and Industrial Computer Science, Cracow, Poland
| | - K Berniak
- AGH University of Krakow, Faculty of Metals Engineering and Industrial Computer Science, Cracow, Poland
| | - J Knapczyk-Korczak
- AGH University of Krakow, Faculty of Metals Engineering and Industrial Computer Science, Cracow, Poland
| | - G Williams
- University of Birmingham, Institute for Microbiology and Infection, B15 2TT Birmingham, UK
| | - J A Bryant
- University of Birmingham, Institute for Microbiology and Infection, B15 2TT Birmingham, UK
| | - N D Nikoi
- University of Nottingham, School of Pharmacy, NG7 2RD Nottingham, UK
| | - M Banzhaf
- University of Birmingham, Institute for Microbiology and Infection, B15 2TT Birmingham, UK
| | - F de Cogan
- University of Nottingham, School of Pharmacy, NG7 2RD Nottingham, UK
| | - U Stachewicz
- AGH University of Krakow, Faculty of Metals Engineering and Industrial Computer Science, Cracow, Poland.
| |
Collapse
|
3
|
Goodall ECA, Morris FC, McKeand SA, Sullivan R, Warner IA, Sheehan E, Boelter G, Icke C, Cunningham AF, Cole JA, Banzhaf M, Bryant JA, Henderson IR. LI-Detector: a Method for Curating Ordered Gene-Replacement Libraries. Microbiol Spectr 2022; 10:e0083322. [PMID: 35856675 PMCID: PMC9431181 DOI: 10.1128/spectrum.00833-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 07/01/2022] [Indexed: 12/04/2022] Open
Abstract
In recent years the availability of genome sequence information has grown logarithmically resulting in the identification of a plethora of uncharacterized genes. To address this gap in functional annotation, many high-throughput screens have been devised to uncover novel gene functions. Gene-replacement libraries are one such tool that can be screened in a high-throughput way to link genotype and phenotype and are key community resources. However, for a phenotype to be attributed to a specific gene, there needs to be confidence in the genotype. Construction of large libraries can be laborious and occasionally errors will arise. Here, we present a rapid and accurate method for the validation of any ordered library where a gene has been replaced or disrupted by a uniform linear insertion (LI). We applied our method (LI-detector) to the well-known Keio library of Escherichia coli gene-deletion mutants. Our method identified 3,718 constructed mutants out of a total of 3,728 confirmed isolates, with a success rate of 99.7% for identifying the correct kanamycin cassette position. This data set provides a benchmark for the purity of the Keio mutants and a screening method for mapping the position of any linear insertion, such as an antibiotic resistance cassette in any ordered library. IMPORTANCE The construction of ordered gene replacement libraries requires significant investment of time and resources to create a valuable community resource. During construction, technical errors may result in a limited number of incorrect mutants being made. Such mutants may confound the output of subsequent experiments. Here, using the remarkable E. coli Keio knockout library, we describe a method to rapidly validate the construction of every mutant.
Collapse
Affiliation(s)
- Emily C. A. Goodall
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Faye C. Morris
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Samantha A. McKeand
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Rudi Sullivan
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Isabel A. Warner
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Emma Sheehan
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Gabriela Boelter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Christopher Icke
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| | - Adam F. Cunningham
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Jeffrey A. Cole
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Manuel Banzhaf
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jack A. Bryant
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Ian R. Henderson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia
| |
Collapse
|
4
|
Boelter G, Bryant JA, Doherty H, Wotherspoon P, Alodaini D, Ma X, Alao MB, Moynihan PJ, Moradigaravand D, Glinkowska M, Knowles TJ, Henderson IR, Banzhaf M. The lipoprotein DolP affects cell separation in Escherichia coli, but not as an upstream regulator of NlpD. Microbiology (Reading) 2022; 168. [PMID: 35604759 DOI: 10.1099/mic.0.001197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial amidases are essential to split the shared envelope of adjunct daughter cells to allow cell separation. Their activity needs to be precisely controlled to prevent cell lysis. In Escherichia coli, amidase activity is controlled by three regulatory proteins NlpD, EnvC and ActS. However, recent studies linked the outer membrane lipoprotein DolP (formerly YraP) as a potential upstream regulator of NlpD. In this study we explored this link in further detail. To our surprise DolP did not modulate amidase activity in vitro and was unable to interact with NlpD in pull-down and MST (MicroScale Thermophoresis) assays. Next, we excluded the hypothesis that ΔdolP phenocopied ΔnlpD in a range of envelope stresses. However, morphological analysis of double deletion mutants of amidases (AmiA, AmiB AmiC) and amidase regulators with dolP revealed that ΔamiAΔdolP and ΔenvCΔdolP mutants display longer chain length compared to their parental strains indicating a role for DolP in cell division. Overall, we present evidence that DolP does not affect NlpD function in vitro, implying that DolP is not an upstream regulator of NlpD. However, DolP may impact daughter cell separation by interacting directly with AmiA or AmiC, or by a yet undiscovered mechanism.
Collapse
Affiliation(s)
- Gabriela Boelter
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Jack A Bryant
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Hannah Doherty
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Peter Wotherspoon
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Dema Alodaini
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Xuyu Ma
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Micheal B Alao
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Patrick J Moynihan
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Danesh Moradigaravand
- Centre for Computational Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Monika Glinkowska
- Department of Bacterial Molecular Genetics, University of Gdansk, Gdańsk, Poland
| | - Timothy J Knowles
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| | - Ian R Henderson
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK.,Institute for Molecular Bioscience, University of Queensland, St. Lucia, Australia
| | - Manuel Banzhaf
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK
| |
Collapse
|
5
|
Freire CA, Silva RM, Ruiz RC, Pimenta DC, Bryant JA, Henderson IR, Barbosa AS, Elias WP. Secreted Autotransporter Toxin (Sat) Mediates Innate Immune System Evasion. Front Immunol 2022; 13:844878. [PMID: 35251044 PMCID: PMC8891578 DOI: 10.3389/fimmu.2022.844878] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
Several strategies are used by Escherichia coli to evade the host innate immune system in the blood, such as the cleavage of complement system proteins by secreted proteases. Members of the Serine Proteases Autotransporters of Enterobacteriaceae (SPATE) family have been described as presenting proteolytic effects against complement proteins. Among the SPATE-encoding genes sat (secreted autotransporter toxin) has been detected in high frequencies among strains of E. coli isolated from bacteremia. Sat has been characterized for its cytotoxic action, but the possible immunomodulatory effects of Sat have not been investigated. Therefore, this study aimed to evaluate the proteolytic effects of Sat on complement proteins and the role in pathogenesis of BSI caused by extraintestinal E. coli (ExPEC). E. coli EC071 was selected as a Sat-producing ExPEC strain. Whole-genome sequencing showed that sat sequences of EC071 and uropathogenic E. coli CFT073 present 99% identity. EC071 was shown to be resistant to the bactericidal activity of normal human serum (NHS). Purified native Sat was used in proteolytic assays with proteins of the complement system and, except for C1q, all tested substrates were cleaved by Sat in a dose and time-dependent manner. Moreover, E. coli DH5α survived in NHS pre-incubated with Sat. EC071-derivative strains harboring sat knockout and in trans complementations producing either active or non-active Sat were tested in a murine sepsis model. Lethality was reduced by 50% when mice were inoculated with the sat mutant strain. The complemented strain producing active Sat partially restored the effect caused by the wild-type strain. The results presented in this study show that Sat presents immunomodulatory effects by cleaving several proteins of the three complement system pathways. Therefore, Sat plays an important role in the establishment of bloodstream infections and sepsis.
Collapse
Affiliation(s)
- Claudia A Freire
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Rosa M Silva
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Rita C Ruiz
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Daniel C Pimenta
- Laboratório de Bioquímica, Instituto Butantan, São Paulo, Brazil
| | - Jack A Bryant
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Ian R Henderson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom.,Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, Australia
| | - Angela S Barbosa
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| |
Collapse
|
6
|
Bryant JA, Riordan L, Watson R, Nikoi ND, Trzaska W, Slope L, Tibbatts C, Alexander MR, Scurr DJ, May RC, de Cogan F. Developing Novel Biointerfaces: Using Chlorhexidine Surface Attachment as a Method for Creating Anti-Fungal Surfaces. Glob Chall 2022; 6:2100138. [PMID: 35602408 PMCID: PMC9121760 DOI: 10.1002/gch2.202100138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/10/2022] [Indexed: 06/15/2023]
Abstract
There is an increasing focus in healthcare environments on combatting antimicrobial resistant infections. While bacterial infections are well reported, infections caused by fungi receive less attention, yet have a broad impact on society and can be deadly. Fungi are eukaryotes with considerable shared biology with humans, therefore limited technologies exist to combat fungal infections and hospital infrastructure is rarely designed for reducing microbial load. In this study, a novel antimicrobial surface (AMS) that is modified with the broad-spectrum biocide chlorhexidine is reported. The surfaces are shown to kill the opportunistic fungal pathogens Candida albicans and Cryptococcus neoformans very rapidly (<15 min) and are significantly more effective than current technologies available on the commercial market, such as silver and copper.
Collapse
Affiliation(s)
- Jack A. Bryant
- Institute of Microbiology and InfectionUniversity of BirminghamBirminghamB15 2TTUK
| | - Lily Riordan
- Institute of Microbiology and InfectionUniversity of BirminghamBirminghamB15 2TTUK
| | - Rowan Watson
- Institute of Microbiology and InfectionUniversity of BirminghamBirminghamB15 2TTUK
| | - Naa Dei Nikoi
- Institute of Microbiology and InfectionUniversity of BirminghamBirminghamB15 2TTUK
| | - Wioleta Trzaska
- School of BiosciencesUniversity of BirminghamBirminghamB15 2TTUK
| | - Louise Slope
- Institute of Microbiology and InfectionUniversity of BirminghamBirminghamB15 2TTUK
| | - Callum Tibbatts
- Institute of Microbiology and InfectionUniversity of BirminghamBirminghamB15 2TTUK
| | - Morgan R. Alexander
- Advanced Materials and Healthcare Technologies DivisionSchool of PharmacyUniversity of NottinghamNottinghamNG7 2RDUK
| | - David J. Scurr
- Advanced Materials and Healthcare Technologies DivisionSchool of PharmacyUniversity of NottinghamNottinghamNG7 2RDUK
| | - Robin C. May
- School of BiosciencesUniversity of BirminghamBirminghamB15 2TTUK
| | - Felicity de Cogan
- Institute of Microbiology and InfectionUniversity of BirminghamBirminghamB15 2TTUK
| |
Collapse
|
7
|
Goodall ECA, Isom GL, Rooke JL, Pullela K, Icke C, Yang Z, Boelter G, Jones A, Warner I, Da Costa R, Zhang B, Rae J, Tan WB, Winkle M, Delhaye A, Heinz E, Collet JF, Cunningham AF, Blaskovich MA, Parton RG, Cole JA, Banzhaf M, Chng SS, Vollmer W, Bryant JA, Henderson IR. Loss of YhcB results in dysregulation of coordinated peptidoglycan, LPS and phospholipid synthesis during Escherichia coli cell growth. PLoS Genet 2021; 17:e1009586. [PMID: 34941903 PMCID: PMC8741058 DOI: 10.1371/journal.pgen.1009586] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 01/07/2022] [Accepted: 11/24/2021] [Indexed: 12/13/2022] Open
Abstract
The cell envelope is essential for viability in all domains of life. It retains enzymes and substrates within a confined space while providing a protective barrier to the external environment. Destabilising the envelope of bacterial pathogens is a common strategy employed by antimicrobial treatment. However, even in one of the best studied organisms, Escherichia coli, there remain gaps in our understanding of how the synthesis of the successive layers of the cell envelope are coordinated during growth and cell division. Here, we used a whole-genome phenotypic screen to identify mutants with a defective cell envelope. We report that loss of yhcB, a conserved gene of unknown function, results in loss of envelope stability, increased cell permeability and dysregulated control of cell size. Using whole genome transposon mutagenesis strategies, we report the comprehensive genetic interaction network of yhcB, revealing all genes with a synthetic negative and a synthetic positive relationship. These genes include those previously reported to have a role in cell envelope biogenesis. Surprisingly, we identified genes previously annotated as essential that became non-essential in a ΔyhcB background. Subsequent analyses suggest that YhcB functions at the junction of several envelope biosynthetic pathways coordinating the spatiotemporal growth of the cell, highlighting YhcB as an as yet unexplored antimicrobial target. All life depends on a cell envelope to enclose the chemical reactions that make life possible. But how do cell envelopes grow? How each component of the cell envelope is incorporated into the envelope at the correct amount, in the correct place, and at the correct time, to prevent cell death, has been a long-standing question in bacteriology. Using a unique combination of high throughput chemical genetic screens we identified yhcB, a conserved gene of unknown function, required for the maintenance of cell envelope integrity in Escherichia coli. Loss of YhcB results in aberrant cell size driven by the production of excess membrane phospholipids. Subsequent molecular and biochemical analyses suggest YhcB influences the spatiotemporal biogenesis of LPS, peptidoglycan and membrane phospholipids. Our data indicate YhcB is a key regulator of cell envelope growth in Gram-negative bacteria playing a crucial role in coordinating cell width, elongation, and division to maintain cell envelope integrity.
Collapse
Affiliation(s)
- Emily C. A. Goodall
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
- * E-mail: (ECAG); (IRH)
| | - Georgia L. Isom
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jessica L. Rooke
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Karthik Pullela
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Christopher Icke
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Zihao Yang
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Gabriela Boelter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Alun Jones
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Isabel Warner
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Rochelle Da Costa
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Bing Zhang
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - James Rae
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Wee Boon Tan
- Department of Chemistry, National University of Singapore, Singapore
| | - Matthias Winkle
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Antoine Delhaye
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Eva Heinz
- Departments of Vector Biology and Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Adam F. Cunningham
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Mark A. Blaskovich
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Australia
| | - Jeff A. Cole
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Manuel Banzhaf
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jack A. Bryant
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Ian R. Henderson
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
- * E-mail: (ECAG); (IRH)
| |
Collapse
|
8
|
Nikoi ND, Berwick M, Bryant JA, Riordan L, Slope L, Peacock AFA, de Cogan F. Stability of Cell-Penetrating Peptide anti-VEGF Formulations for the Treatment of Age-Related Macular Degeneration. Curr Eye Res 2021; 46:751-757. [PMID: 33896277 DOI: 10.1080/02713683.2020.1830117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AIM The development of a polyarginine cell-penetrating peptide (CPP) could enable the treatment of age-related macular degeneration, with drugs like bevacizumab, to be administered using eye drops instead of intravitreal injections. Topical formulations have a vast potential impact on healthcare by increasing patient compliance while reducing the financial burden. However, as the ocular preparations may contain several doses, it is essential to understand the stability of the bevacizumab+CPP conjugate produced. MATERIALS AND METHODS In this work, we examine the stability of a bevacizumab solution with and without cell-penetrating peptide using dynamic light scattering and circular dichroism to assess the physical stability. We use HPLC to assess the chemical stability and ELISA to assess its biological activity. We also examine the potential of the CPP to be used as an antimicrobial agent in place of preservatives in the eye drop. RESULTS The structural stability of bevacizumab with and without the CPP was found not to be affected by temperature: samples stored at either 20°C or 4°C were identical in behavior. However, physical instability was observed after five weeks, leading to aggregation and precipitation. Further investigation revealed that the addition of the polypeptide led to increased aggregation, as revealed through dynamic light scattering and concentration analysis of the peptide through HPLC. Complexing the bevacizumab with CPP had no effect on biological stability or degradation. CONCLUSIONS Our findings suggest that the shelf life of CPP+bevacizumab complexes is at least 38 days from its initial formulation. Currently, the mechanism for aggregation is not fully understood but does not appear to occur through chemical degradation.
Collapse
Affiliation(s)
- Naa-Dei Nikoi
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK.,Pharmacy Department, University Hospitals Coventry and Warwickshire Trust, Coventry, UK
| | - Matthew Berwick
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK.,School of Chemistry, University of Birmingham, Birmingham, UK
| | - Jack A Bryant
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Lily Riordan
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Louise Slope
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | | | - Felicity de Cogan
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| |
Collapse
|
9
|
Seabright AP, Fine NHF, Barlow JP, Lord SO, Musa I, Gray A, Bryant JA, Banzhaf M, Lavery GG, Hardie DG, Hodson DJ, Philp A, Lai YC. AMPK activation induces mitophagy and promotes mitochondrial fission while activating TBK1 in a PINK1-Parkin independent manner. FASEB J 2020; 34:6284-6301. [PMID: 32201986 PMCID: PMC7212019 DOI: 10.1096/fj.201903051r] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/13/2020] [Accepted: 02/28/2020] [Indexed: 12/14/2022]
Abstract
Mitophagy is a key process regulating mitochondrial quality control. Several mechanisms have been proposed to regulate mitophagy, but these have mostly been studied using stably expressed non‐native proteins in immortalized cell lines. In skeletal muscle, mitophagy and its molecular mechanisms require more thorough investigation. To measure mitophagy directly, we generated a stable skeletal muscle C2C12 cell line, expressing a mitophagy reporter construct (mCherry‐green fluorescence protein‐mtFIS1101-152). Here, we report that both carbonyl cyanide m‐chlorophenyl hydrazone (CCCP) treatment and adenosine monophosphate activated protein kinase (AMPK) activation by 991 promote mitochondrial fission via phosphorylation of MFF and induce mitophagy by ~20%. Upon CCCP treatment, but not 991, ubiquitin phosphorylation, a read‐out of PTEN‐induced kinase 1 (PINK1) activity, and Parkin E3 ligase activity toward CDGSH iron sulfur domain 1 (CISD1) were increased. Although the PINK1‐Parkin signaling pathway is active in response to CCCP treatment, we observed no change in markers of mitochondrial protein content. Interestingly, our data shows that TANK‐binding kinase 1 (TBK1) phosphorylation is increased after both CCCP and 991 treatments, suggesting TBK1 activation to be independent of both PINK1 and Parkin. Finally, we confirmed in non‐muscle cell lines that TBK1 phosphorylation occurs in the absence of PINK1 and is regulated by AMPK‐dependent signaling. Thus, AMPK activation promotes mitophagy by enhancing mitochondrial fission (via MFF phosphorylation) and autophagosomal engulfment (via TBK1 activation) in a PINK1‐Parkin independent manner.
Collapse
Affiliation(s)
- Alex P Seabright
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Nicholas H F Fine
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Jonathan P Barlow
- Mitochondrial Profiling Centre, University of Birmingham, Birmingham, UK
| | - Samuel O Lord
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Ibrahim Musa
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Alexander Gray
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Jack A Bryant
- Institute of Microbiology and Infection, School of Bioscience, University of Birmingham, Birmingham, UK
| | - Manuel Banzhaf
- Institute of Microbiology and Infection, School of Bioscience, University of Birmingham, Birmingham, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, UK
| | - D Grahame Hardie
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,Centre of Membrane Proteins and Receptors, University of Birmingham, Birmingham, UK
| | - Andrew Philp
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.,St Vincent's Clinical School, UNSW Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Yu-Chiang Lai
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK.,Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.,Mitochondrial Profiling Centre, University of Birmingham, Birmingham, UK.,MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, University of Birmingham, Birmingham, UK
| |
Collapse
|
10
|
Domínguez-Medina CC, Pérez-Toledo M, Schager AE, Marshall JL, Cook CN, Bobat S, Hwang H, Chun BJ, Logan E, Bryant JA, Channell WM, Morris FC, Jossi SE, Alshayea A, Rossiter AE, Barrow PA, Horsnell WG, MacLennan CA, Henderson IR, Lakey JH, Gumbart JC, López-Macías C, Bavro VN, Cunningham AF. Outer membrane protein size and LPS O-antigen define protective antibody targeting to the Salmonella surface. Nat Commun 2020; 11:851. [PMID: 32051408 PMCID: PMC7015928 DOI: 10.1038/s41467-020-14655-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 01/23/2020] [Indexed: 11/28/2022] Open
Abstract
Lipopolysaccharide (LPS) O-antigen (O-Ag) is known to limit antibody binding to surface antigens, although the relationship between antibody, O-Ag and other outer-membrane antigens is poorly understood. Here we report, immunization with the trimeric porin OmpD from Salmonella Typhimurium (STmOmpD) protects against infection. Atomistic molecular dynamics simulations indicate this is because OmpD trimers generate footprints within the O-Ag layer sufficiently sized for a single IgG Fab to access. While STmOmpD differs from its orthologue in S. Enteritidis (SEn) by a single amino-acid residue, immunization with STmOmpD confers minimal protection to SEn. This is due to the OmpD-O-Ag interplay restricting IgG binding, with the pairing of OmpD with its native O-Ag being essential for optimal protection after immunization. Thus, both the chemical and physical structure of O-Ag are key for the presentation of specific epitopes within proteinaceous surface-antigens. This enhances combinatorial antigenic diversity in Gram-negative bacteria, while reducing associated fitness costs. The O-antigen of LPS is known to limit the binding of antibody to bacterial surface antigens. Here the AUs show that the chemical and physical structure of the O-antigen are central factors in limiting the exposure of surface antigens to antibodies during Salmonella infection, thus defining their protective qualities.
Collapse
Affiliation(s)
- C Coral Domínguez-Medina
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Marisol Pérez-Toledo
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK.,Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI" Mexican Institute for Social Security, Mexico City, Mexico
| | - Anna E Schager
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jennifer L Marshall
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Charlotte N Cook
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Saeeda Bobat
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Hyea Hwang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta GA, 30332, USA
| | - Byeong Jae Chun
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta GA, 30332, USA
| | - Erin Logan
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Anzio Road, Cape Town, Western Cape, 7925, South Africa
| | - Jack A Bryant
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Will M Channell
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Faye C Morris
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Sian E Jossi
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Areej Alshayea
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Amanda E Rossiter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Paul A Barrow
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Leicestershire, LE12 5RD, UK
| | - William G Horsnell
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Anzio Road, Cape Town, Western Cape, 7925, South Africa
| | - Calman A MacLennan
- Jenner Institute, Nuffield Department of Medicine, Old Road Campus Research Building, Roosevelt Drive, University of Oxford, Oxford, OX3 7DQ, UK
| | - Ian R Henderson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, UK
| | - James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Constantino López-Macías
- Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre "Siglo XXI" Mexican Institute for Social Security, Mexico City, Mexico
| | - Vassiliy N Bavro
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
| | - Adam F Cunningham
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK. .,Institute of Microbiology and Infection, University of Birmingham, Birmingham, B15 2TT, UK.
| |
Collapse
|
11
|
Phua AIH, Tara SW, Le TT, Bryant JA, Toh DFK, Ang BWY, Su B, Cook SA, Chin CWL. P1419 Sex-related differences in cardiac remodeling in health and hypertension. Eur Heart J Cardiovasc Imaging 2020. [DOI: 10.1093/ehjci/jez319.851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Funding Acknowledgements
National Medical Research Council
OnBehalf
National Heart Centre Singapore
BACKGROUND
Adverse cardiac remodelling is associated with worse cardiovascular outcomes. Development of left ventricular hypertrophy (defined as increased myocardial mass) is a complex process mediated by myocardial wall thickening and/or ventricular dilatation. Sex-related differences in the relationship between myocardial mass and wall thickening/ventricular dilatation have not been well-described.
PURPOSE
We examine differences in determinants and patterns of cardiac remodeling between males and females.
METHODS
Comprehensive cardiovascular magnetic resonance imaging was performed in 1006 participants: 316 healthy volunteers (50% males, 46 ± 14 years) and 690 asymptomatic hypertensive patients (60% males, 57 ± 11 years). Myocardial mass, ventricular volumes and maximal myocardial wall thickness (across 16 myocardial segments) were measured using standardized contouring techniques. Clinically relevant variables (age, weight, height, and adiposity) that demonstrated significant univariate association with myocardial mass (P < 0.05) were selected in the multivariable linear regression model using the forward approach.
RESULTS
Increased body weight, lower body fat composition and higher systolic blood pressures were independently associated with increased myocardial mass in healthy volunteers (males and females) and hypertensive females. In hypertensive males, only increased body weight and elevated systolic blood pressure were independently associated with increased myocardial mass.
The association between myocardial mass and ventricular volumes was almost identical between males and females (P = 0.65 for interaction; Figure). Conversely, there was a significant gender-related difference in the association between wall thickness and myocardial mass after adjusting for potential confounders (P < 0.001 for interaction). Concentric remodeling was initially more evident in males; but further with increase, myocardial mass was associated with greater concentric remodeling in females (Figure). Similar results were observed when analyses were performed separately in healthy volunteers and hypertensive patients.
CONCLUSION
There were sex-related differences in concentric remodeling at progressive stages of myocardial hypertrophy that may explain the higher prevalence of heart failure with preserved ejection fraction reported in females.
Abstract P1419 Figure
Collapse
Affiliation(s)
- A I H Phua
- Flinders University, Adelaide, Australia
| | - S W Tara
- Flinders University, Adelaide, Australia
| | - T T Le
- National Heart Centre Singapore, Singapore, Singapore
| | - J A Bryant
- National Heart Centre Singapore, Singapore, Singapore
| | - D F K Toh
- National Heart Centre Singapore, Singapore, Singapore
| | - B W Y Ang
- National Heart Centre Singapore, Singapore, Singapore
| | - B Su
- National Heart Centre Singapore, Singapore, Singapore
| | - S A Cook
- National Heart Centre Singapore, Singapore, Singapore
| | - C W L Chin
- National Heart Centre Singapore, Singapore, Singapore
| |
Collapse
|
12
|
Santos FF, Yamamoto D, Abe CM, Bryant JA, Hernandes RT, Kitamura FC, Castro FS, Valiatti TB, Piazza RMF, Elias WP, Henderson IR, Gomes TAT. The Type III Secretion System (T3SS)-Translocon of Atypical Enteropathogenic Escherichia coli (aEPEC) Can Mediate Adherence. Front Microbiol 2019; 10:1527. [PMID: 31338081 PMCID: PMC6629874 DOI: 10.3389/fmicb.2019.01527] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 06/18/2019] [Indexed: 12/18/2022] Open
Abstract
The intimin protein is the major adhesin involved in the intimate adherence of atypical enteropathogenic Escherichia coli (aEPEC) strains to epithelial cells, but little is known about the structures involved in their early colonization process. A previous study demonstrated that the type III secretion system (T3SS) plays an additional role in the adherence of an Escherichia albertii strain. Therefore, we assumed that the T3SS could be related to the adherence efficiency of aEPEC during the first stages of contact with epithelial cells. To test this hypothesis, we examined the adherence of seven aEPEC strains and their eae (intimin) isogenic mutants in the standard HeLa adherence assay and observed that all wild-type strains were adherent while five isogenic eae mutants were not. The two eae mutant strains that remained adherent were then used to generate the eae/escN double mutants (encoding intimin and the T3SS ATPase, respectively) and after the adherence assay, we observed that one strain lost its adherence capacity. This suggested a role for the T3SS in the initial adherence steps of this strain. In addition, we demonstrated that this strain expressed the T3SS at significantly higher levels when compared to the other wild-type strains and that it produced longer translocon-filaments. Our findings reveal that the T3SS-translocon can play an additional role as an adhesin at the beginning of the colonization process of aEPEC.
Collapse
Affiliation(s)
- Fernanda F Santos
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Denise Yamamoto
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Cecilia M Abe
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Jack A Bryant
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Rodrigo T Hernandes
- Departamento de Microbiologia e Imunologia, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, Brazil
| | - Felipe C Kitamura
- Departamento de Diagnóstico por Imagem, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Felipe S Castro
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Tiago B Valiatti
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Waldir P Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Ian R Henderson
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Tânia A T Gomes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| |
Collapse
|
13
|
Hughes GW, Hall SCL, Laxton CS, Sridhar P, Mahadi AH, Hatton C, Piggot TJ, Wotherspoon PJ, Leney AC, Ward DG, Jamshad M, Spana V, Cadby IT, Harding C, Isom GL, Bryant JA, Parr RJ, Yakub Y, Jeeves M, Huber D, Henderson IR, Clifton LA, Lovering AL, Knowles TJ. Evidence for phospholipid export from the bacterial inner membrane by the Mla ABC transport system. Nat Microbiol 2019; 4:1692-1705. [DOI: 10.1038/s41564-019-0481-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 05/03/2019] [Indexed: 12/24/2022]
|
14
|
Le TT, Bryant JA, Ang BWY, Pua CJ, Su BWY, Ho PY, Lim S, Huang W, Lee PT, Tang HC, Chin CT, Tan BY, Cook SA, Chin CW. 202Discriminating between exercise induced cardiac remodeling and dilated cardiomyopathy using exercise cardiac MRI. Eur Heart J Cardiovasc Imaging 2019. [DOI: 10.1093/ehjci/jez128.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- T T Le
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - J A Bryant
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - B W Y Ang
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - C J Pua
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - B W Y Su
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - P Y Ho
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - S Lim
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - W Huang
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - P T Lee
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - H C Tang
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - C T Chin
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - B Y Tan
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - S A Cook
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| | - C W Chin
- National Heart Centre Singapore (NHCS), Singapore, Singapore
| |
Collapse
|
15
|
Yeow CES, Cai J, Le TT, Bryant JA, Su B, Chin CWL. P3696Determinants of left ventricular trabeculations in hypertensive patients. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- C E S Yeow
- Royal College of Surgeons in Ireland, Dublin, Ireland
| | - J Cai
- National Heart Centre Singapore, Singapore, Singapore
| | - T T Le
- National Heart Centre Singapore, Singapore, Singapore
| | - J A Bryant
- National Heart Centre Singapore, Singapore, Singapore
| | - B Su
- National Heart Centre Singapore, Singapore, Singapore
| | - C W L Chin
- National Heart Centre Singapore, Singapore, Singapore
| | | |
Collapse
|
16
|
Sendy B, Lee DJ, Busby SJW, Bryant JA. RNA polymerase supply and flux through the lac operon in Escherichia coli. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2016.0080. [PMID: 27672157 PMCID: PMC5052750 DOI: 10.1098/rstb.2016.0080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2016] [Indexed: 11/12/2022] Open
Abstract
Chromatin immunoprecipitation, followed by quantification of immunoprecipitated DNA, can be used to measure RNA polymerase binding to any DNA segment in Escherichia coli. By calibrating measurements against the signal from a single RNA polymerase bound at a single promoter, we can calculate both promoter occupancy levels and the flux of transcribing RNA polymerase through transcription units. Here, we have applied the methodology to the E. coli lactose operon promoter. We confirm that promoter occupancy is limited by recruitment and that the supply of RNA polymerase to the lactose operon promoter depends on its location in the E. coli chromosome. Measurements of RNA polymerase binding to DNA segments within the lactose operon show that flux of RNA polymerase through the operon is low, with, on average, over 18 s elapsing between the passage of transcribing polymerases. Similar low levels of flux were found when semi-synthetic promoters were used to drive transcript initiation, even when the promoter elements were changed to ensure full occupancy of the promoter by RNA polymerase. This article is part of the themed issue ‘The new bacteriology’.
Collapse
Affiliation(s)
- Bandar Sendy
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - David J Lee
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Stephen J W Busby
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Jack A Bryant
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| |
Collapse
|
17
|
Isom GL, Davies NJ, Chong ZS, Bryant JA, Jamshad M, Sharif M, Cunningham AF, Knowles TJ, Chng SS, Cole JA, Henderson IR. MCE domain proteins: conserved inner membrane lipid-binding proteins required for outer membrane homeostasis. Sci Rep 2017; 7:8608. [PMID: 28819315 PMCID: PMC5561183 DOI: 10.1038/s41598-017-09111-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 07/20/2017] [Indexed: 01/12/2023] Open
Abstract
Bacterial proteins with MCE domains were first described as being important for Mammalian Cell Entry. More recent evidence suggests they are components of lipid ABC transporters. In Escherichia coli, the single-domain protein MlaD is known to be part of an inner membrane transporter that is important for maintenance of outer membrane lipid asymmetry. Here we describe two multi MCE domain-containing proteins in Escherichia coli, PqiB and YebT, the latter of which is an orthologue of MAM-7 that was previously reported to be an outer membrane protein. We show that all three MCE domain-containing proteins localise to the inner membrane. Bioinformatic analyses revealed that MCE domains are widely distributed across bacterial phyla but multi MCE domain-containing proteins evolved in Proteobacteria from single-domain proteins. Mutants defective in mlaD, pqiAB and yebST were shown to have distinct but partially overlapping phenotypes, but the primary functions of PqiB and YebT differ from MlaD. Complementing our previous findings that all three proteins bind phospholipids, results presented here indicate that multi-domain proteins evolved in Proteobacteria for specific functions in maintaining cell envelope homeostasis.
Collapse
Affiliation(s)
- Georgia L Isom
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Nathaniel J Davies
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Zhi-Soon Chong
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Jack A Bryant
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Mohammed Jamshad
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Maria Sharif
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Adam F Cunningham
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Timothy J Knowles
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Jeffrey A Cole
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Ian R Henderson
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom.
| |
Collapse
|
18
|
Sellars LE, Bryant JA, Sánchez-Romero MA, Sánchez-Morán E, Busby SJW, Lee DJ. Development of a new fluorescent reporter:operator system: location of AraC regulated genes in Escherichia coli K-12. BMC Microbiol 2017; 17:170. [PMID: 28774286 PMCID: PMC5543585 DOI: 10.1186/s12866-017-1079-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/18/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In bacteria, many transcription activator and repressor proteins regulate multiple transcription units that are often distally distributed on the bacterial genome. To investigate the subcellular location of DNA bound proteins in the folded bacterial nucleoid, fluorescent reporters have been developed which can be targeted to specific DNA operator sites. Such Fluorescent Reporter-Operator System (FROS) probes consist of a fluorescent protein fused to a DNA binding protein, which binds to an array of DNA operator sites located within the genome. Here we have developed a new FROS probe using the Escherichia coli MalI transcription factor, fused to mCherry fluorescent protein. We have used this in combination with a LacI repressor::GFP protein based FROS probe to assess the cellular location of commonly regulated transcription units that are distal on the Escherichia coli genome. RESULTS We developed a new DNA binding fluorescent reporter, consisting of the Escherichia coli MalI protein fused to the mCherry fluorescent protein. This was used in combination with a Lac repressor:green fluorescent protein fusion to examine the spatial positioning and possible co-localisation of target genes, regulated by the Escherichia coli AraC protein. We report that induction of gene expression with arabinose does not result in co-localisation of AraC-regulated transcription units. However, measurable repositioning was observed when gene expression was induced at the AraC-regulated promoter controlling expression of the araFGH genes, located close to the DNA replication terminus on the chromosome. Moreover, in dividing cells, arabinose-induced expression at the araFGH locus enhanced chromosome segregation after replication. CONCLUSION Regions of the chromosome regulated by AraC do not colocalise, but transcription events can induce movement of chromosome loci in bacteria and our observations suggest a role for gene expression in chromosome segregation.
Collapse
Affiliation(s)
- Laura E. Sellars
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| | - Jack A. Bryant
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| | | | | | - Stephen J. W. Busby
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| | - David J. Lee
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
- Department of Life Sciences, Birmingham City University, Edgbaston, Birmingham, B15 3TN UK
| |
Collapse
|
19
|
Abstract
In eukaryotes, the location of a gene on the chromosome is known to affect its expression, but such position effects are poorly understood in bacteria. Here, using Escherichia coli K-12, we demonstrate that expression of a reporter gene cassette, comprised of the model E. coli lac promoter driving expression of gfp, varies by ∼300-fold depending on its precise position on the chromosome. At some positions, expression was more than 3-fold higher than at the natural lac promoter locus, whereas at several other locations, the reporter cassette was completely silenced: effectively overriding local lac promoter control. These effects were not due to differences in gene copy number, caused by partially replicated genomes. Rather, the differences in gene expression occur predominantly at the level of transcription and are mediated by several different features that are involved in chromosome organization. Taken together, our findings identify a tier of gene regulation above local promoter control and highlight the importance of chromosome position effects on gene expression profiles in bacteria.
Collapse
Affiliation(s)
- Jack A Bryant
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Laura E Sellars
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Stephen J W Busby
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - David J Lee
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| |
Collapse
|
20
|
Browning DF, Wells TJ, França FLS, Morris FC, Sevastsyanovich YR, Bryant JA, Johnson MD, Lund PA, Cunningham AF, Hobman JL, May RC, Webber MA, Henderson IR. Laboratory adapted Escherichia coli K-12 becomes a pathogen of Caenorhabditis elegans upon restoration of O antigen biosynthesis. Mol Microbiol 2013; 87:939-50. [PMID: 23350972 DOI: 10.1111/mmi.12144] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2012] [Indexed: 01/13/2023]
Abstract
Escherichia coli has been the leading model organism for many decades. It is a fundamental player in modern biology, facilitating the molecular biology revolution of the last century. The acceptance of E. coli as model organism is predicated primarily on the study of one E. coli lineage; E. coli K-12. However, the antecedents of today's laboratory strains have undergone extensive mutagenesis to create genetically tractable offspring but which resulted in loss of several genetic traits such as O antigen expression. Here we have repaired the wbbL locus, restoring the ability of E. coli K-12 strain MG1655 to express the O antigen. We demonstrate that O antigen production results in drastic alterations of many phenotypes and the density of the O antigen is critical for the observed phenotypes. Importantly, O antigen production enables laboratory strains of E. coli to enter the gut of the Caenorhabditis elegans worm and to kill C. elegans at rates similar to pathogenic bacterial species. We demonstrate C. elegans killing is a feature of other commensal E. coli. We show killing is associated with bacterial resistance to mechanical shear and persistence in the C. elegans gut. These results suggest C. elegans is not an effective model of human-pathogenic E. coli infectious disease.
Collapse
Affiliation(s)
- Douglas F Browning
- School of Immunity and Infection, University of Birmingham, Birmingham, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
|
22
|
Bryant JA. John Bryant takes a closer look at some of this month's Original Articles. Ann Bot 2009; 103:iii-iv. [PMID: 19372242 PMCID: PMC2707914 DOI: 10.1093/aob/mcp094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
|
23
|
Bryant JA. John Bryant takes a closer look at some of this month's Original Articles. Ann Bot 2009; 103:iii-iv. [PMID: 19074448 PMCID: PMC2707298 DOI: 10.1093/aob/mcn250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
|
24
|
Bryant JA, Drage NA, Richmond S. Study of the scan uniformity from an i-CAT cone beam computed tomography dental imaging system. Dentomaxillofac Radiol 2008; 37:365-74. [PMID: 18812597 DOI: 10.1259/dmfr/13227258] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVES As part of an ongoing programme to improve diagnosis and treatment planning relevant to implant placement, orthodontic treatment and dentomaxillofacial surgery, a study has been made of the spatial accuracy and density response of an i-CAT, a cone beam CT (CBCT) dental imaging system supplied by Imaging Sciences International Inc. METHODS Custom-made phantoms using acrylic sheet and water were used for measurements on spatial accuracy, density response and noise. The measurements were made over a period of several months on a clinical machine rather than on a machine dedicated to research. RESULTS Measurements on a precision grid showed the spatial accuracy to be universally within the tolerance of +/-1 pixel. The density response and the noise in the data were found to depend strongly on the mass in the slice being scanned. CONCLUSIONS The density response was subject to two effects. The first effect changes the whole slice uniformly and linearly depends on the total mass in the slice. The second effect exists when there is mass outside the field of view, dubbed the "exo-mass" effect. This effect lowers the measured CT number rapidly at the scan edge furthest from the exo-mass and raises it on the adjacent edge. The noise also depended quasi-linearly on the mass in the slice. Some general performance rules were drafted to describe these effects and a preliminary correction algorithm was constructed.
Collapse
Affiliation(s)
- J A Bryant
- Dental School, Dental Health and Biological Sciences, Cardiff University, Heath Park, Cardiff CF14 4XY, Wales, UK.
| | | | | |
Collapse
|
25
|
Bryant JA. John Bryant takes a closer look at some of this month's Original Articles. Ann Bot 2008; 102:vii-viii. [PMID: 18708449 PMCID: PMC2701805 DOI: 10.1093/aob/mcn148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
26
|
Bryant JA. John Bryant takes a closer look at some of this month's Original Articles. Ann Bot 2008; 102:v-vi. [PMID: 18628264 PMCID: PMC2712360 DOI: 10.1093/aob/mcn123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
27
|
Bryant JA. John Bryant takes a closer look at some of this month's Original Articles. Ann Bot 2008; 102:v-vi. [PMID: 18562469 PMCID: PMC2712433 DOI: 10.1093/aob/mcn098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
28
|
Bryant JA. John Bryant takes a closer look at some of this month's Original Articles. Ann Bot 2008; 101:NP. [PMID: 18426808 PMCID: PMC2710222 DOI: 10.1093/aob/mcn060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
29
|
Bryant JA, Siddiqi NJ, Loveday EJ, Irvine GH. Presurgical, ultrasound-guided anchor-wire marking of impalpable cervical lymph nodes. J Laryngol Otol 2006; 119:627-8. [PMID: 16102218 DOI: 10.1258/0022215054516241] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This case illustrates the surgical use of wire localization, a well tried technique from a different field of surgery, in the removal of an ultrasound-detected, impalpable deep lower cervical lymph node in a high-risk patient. A localization needle with an echogenic tip was placed freehand
under ultrasound guidance, immediately before surgery. The imaging and marking of the impalpable cervical lymph node resulted in a precise surgical dissection and a reduction in operating time whilst minimizing risks to the patient and staff.
Collapse
Affiliation(s)
- J A Bryant
- Department of Oral & Maxillofacial Surgery, Southmead Hospital, Bristol, UK
| | | | | | | |
Collapse
|
30
|
Hengartner MO, Bryant JA. Apoptotic cell death: from worms to wombats ... but what about the weeds? Symp Soc Exp Biol 2005; 52:1-12. [PMID: 12090000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- M O Hengartner
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York, NY 11724, USA
| | | |
Collapse
|
31
|
Anderson LE, Bryant JA, Carol AA. Both chloroplastic and cytosolic phosphoglycerate kinase isozymes are present in the pea leaf nucleus. Protoplasma 2004; 223:103-10. [PMID: 15221515 DOI: 10.1007/s00709-004-0041-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Accepted: 11/27/2003] [Indexed: 05/24/2023]
Abstract
Phosphoglycerate kinase (EC 2.7.2.3) occurs in chloroplasts, cytosol, and nuclei in higher plants. Immunocytolocalization experiments with isozyme-specific antibodies indicate that both the chloroplastic and the cytosolic forms of the enzyme are present in the pea (Pisum sativum L.) leaf nucleus.
Collapse
Affiliation(s)
- L E Anderson
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60607-7060, USA.
| | | | | |
Collapse
|
32
|
Abstract
OBJECTIVES To examine the ease with which underage smokers can purchase cigarettes online using money orders and to evaluate the effectiveness of internet filtering programs in blocking access to internet cigarette vendors (ICVs). DESIGN Four young people purchased 32 money orders using 32 different names to buy one carton of cigarettes for each named individual. Each money order was subsequently mailed to a different ICV in the USA. No age related information accompanied these online orders. Two internet filtering programs ("Bess" and filtertobacco.org) were tested for their relative efficacy in blocking access to ICV sites. RESULTS Of the 32 orders placed, four orders never reached the intended ICV. Of the remaining 28 orders, 20 (71%) were filled despite a lack of age verification. Only four (14%) of the orders received were rejected because they lacked proof of age. "Bess" blocked access to 84% and filtertobacco.org to 94% of the ICV sites. CONCLUSIONS Although underage smokers can easily purchase cigarettes online using money orders, access to these sites can be largely blocked if appropriate filtering devices are installed.
Collapse
Affiliation(s)
- J A Bryant
- School of Communication, Annenberg School for Communication, University of Southern California, Los Angeles, California 90089-0281, USA
| | | | | |
Collapse
|
33
|
Abstract
The purpose of this study was to ascertain if positioning of the feet for radiographic assessment produces significant variations in measured angles, and if measurements taken from radiographs taken on two separate occasions are reproducible. Weightbearing x-rays were taken of both feet of ten male healthy subjects in two standardized positions: 1) the angle and base of gait and 2) the feet together and straight-ahead positions. The radiographs were repeated 2 weeks later. The results failed to demonstrate significant differences of radiographic measurements between the two specific foot-positioning methods. No significant differences were found between radiographic measurements of normal feet taken on different occasions. A strong correlation of the repeated measures suggests that weightbearing foot radiographs can be reliably reproduced.
Collapse
Affiliation(s)
- J A Bryant
- Australasian College of Podiatric Surgeons, West Perth, WA, Australia
| |
Collapse
|
34
|
Bryant JA, Moore K, Aves SJ. Origins and complexes: the initiation of DNA replication. J Exp Bot 2001; 52:193-202. [PMID: 11283163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Eukaryotic DNA is organized for replication as multiple replicons. DNA synthesis in each replicon is initiated at an origin of replication. In both budding yeast, Saccharomyces cerevisiae and fission yeast, Schizosaccharomyces pombe, origins contain specific sequences that are essential for initiation, although these differ significantly between the two yeasts with those of S. pombe being more complex then those of S. cerevisiae. However, it is not yet clear whether the replication origins of plants contain specific essential sequences or whether origin sites are determined by features of chromatin structure. In all eukaryotes there are several biochemical events that must take place before initiation can occur. These are the marking of the origins by the origin recognition complex (ORC), the loading onto the origins, in a series of steps, of origin activation factors including the MCM proteins, and the initial denaturation of the double helix to form a replication "bubble". Only then can the enzymes that actually initiate replication, primase and DNA polymerase-alpha, gain access to the template. In many cells this complex series of events occurs only once per cell cycle, ensuring that DNA is not re-replicated within one cycle. However, regulated re-replication of DNA within one cell cycle (DNA endoreduplication) is relatively common in plants, indicating that the "once-per-cycle" controls can be overridden.
Collapse
Affiliation(s)
- J A Bryant
- School of Biological Sciences, University of Exeter, Washington Singer Laboratories, Perry Road, Exeter EX4 4QG, UK.
| | | | | |
Collapse
|
35
|
Bryant JA, Brice DC, Fitchett PN, Anderson LE. A novel DNA-binding protein associated with DNA polymerase-alpha in pea stimulates polymerase activity on infrequently primed templates. J Exp Bot 2000; 51:1945-1947. [PMID: 11113173 DOI: 10.1093/jexbot/51.352.1945] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A 42 kDa DNA-binding protein is associated with DNA polymerase-alpha-primase in pea (Pisum sativum). In a previous publication it was shown that the protein has strong preference for ds-ss junctions in DNA, including the cohesive termini generated by restriction endonucleases. In this paper it is shown that when the DNA-binding protein is added back to polymerase-primase, the protein stimulates the activity of the polymerase. The stimulation is particularly marked when M13 DNA, primed with a single sequencing primer or primed with oligoribonucleotides by the polymerase's associated primase activity, is used as a template. The stimulation of polymerase activity is not caused by an increase in processivity. These data lead to the suggestion that the 42 kDa DNA-binding protein is a primer-recognition protein.
Collapse
Affiliation(s)
- J A Bryant
- School of Biological Sciences, University of Exeter, Exeter EX4 4QG, UK. Department of Biological Sciences, University of Illinois, Chicago, IL 60607-7060, USA.
| | | | | | | |
Collapse
|
36
|
Abstract
We describe a new triply tuned (e(-), (1)H, and (13)C) resonance structure operating at an electron Larmor frequency of 139.5 GHz for dynamic nuclear polarization (DNP) and electron nuclear double-resonance (ENDOR) experiments. In contrast to conventional double-resonance structures, the body of the microwave cavity simultaneously acts as a NMR coil, allowing for increased efficiency of radiofrequency irradiation while maintaining a high quality factor for microwave irradiation. The resonator design is ideal for low-gamma-nuclei ENDOR, where sensitivity is limited by the fact that electron spin relaxation times are on the order of the RF pulse lengths. The performance is demonstrated with (2)H ENDOR on a standard perdeuterated bis-diphenylene-phenyl-allyl stable radical. In DNP experiments, we show that the use of this resonator, combined with a low microwave power setup (17 mW), leads to significantly higher (1)H signal enhancement (epsilon approximately 400 +/- 50) than previously achieved at 5-T fields. The results emphasize the importance of optimizing the microwave B(1) field by improving either the quality factor of the microwave resonator or the microwave power level.
Collapse
Affiliation(s)
- V Weis
- Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | | | | | |
Collapse
|
37
|
Bennati M, Farrar CT, Bryant JA, Inati SJ, Weis V, Gerfen GJ, Riggs-Gelasco P, Stubbe J, Griffin RG. Pulsed electron-nuclear double resonance (ENDOR) at 140 GHz. J Magn Reson 1999; 138:232-243. [PMID: 10341127 DOI: 10.1006/jmre.1999.1727] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We describe a spectrometer for pulsed ENDOR at 140 GHz, which is based on microwave IMPATT diode amplifiers and a probe consisting of a TE011 cavity with a high-quality resonance circuit for variable radiofrequency irradiation. For pulsed EPR we obtain an absolute sensitivity of 3x10(9) spins/Gauss at 20 K. The performance of the spectrometer is demonstrated with pulsed ENDOR spectra of a standard bis-diphenylene-phenyl-allyl (BDPA) doped into polystyrene and of the tyrosyl radical from E. coli ribonucleotide reductase (RNR). The EPR spectrum of the RNR tyrosyl radical displays substantial g-anisotropy at 5 T and is used to demonstrate orientation-selective Davies-ENDOR.
Collapse
Affiliation(s)
- M Bennati
- Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Affiliation(s)
- J A Bryant
- Flow Cytometry, Australian Red Cross Blood Service-NSW, Sydney, New South Wales, Australia.
| | | | | |
Collapse
|
39
|
|
40
|
Bryant JA. The last frontier: the road to the C. Trends Biotechnol 1998; 16:449. [PMID: 9830152 DOI: 10.1016/s0167-7799(98)91238-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
|
41
|
Abstract
DNA polymerase-alpha-primase may be isolated from pea shoot tip cells as a large (1.25 x 10(6) Da) multi-protein complex. The complex exhibits several enzyme activities and also binds to DNA. One of the DNA-binding activities has been purified as a 42 kDa polypeptide. The binding of this polypeptide to linear DNA fragments and to open circular plasmids has been studied by electron microscopy. The protein binds to restriction enzyme-generated cohesive ends of linear fragments and also exhibits some interstitial binding. Binding at the ends of linear molecules is very markedly reduced if the molecules are previously treated with S1 nuclease. The protein also binds to open circular plasmids; the number of binding sites is increased by exposing the plasmids to gamma-irradiation prior to the DNA-protein interaction. In these experiments, the number of protein units bound is directly related to the radiation dose. With both linear and open circular molecules, binding of the protein to the DNA leads to an apparent shortening of the DNA molecule. These observations, taken with the finding that the protein does not bind to completely single-stranded DNA, lead to the suggestion that the protein binds to double-stranded-single-stranded (ds-ss) junctions in DNA and that binding causes the DNA to wrap round the protein.
Collapse
Affiliation(s)
- S K Burton
- Department of Biological Sciences, University of Exeter, UK
| | | | | |
Collapse
|
42
|
Abstract
BACKGROUND Absolute counts of CD4+ T-lymphocytes are used in the management of patients with human immunodeficiency virus infection. Low absolute counts of CD3+CD4+ cells have also been observed in healthy people--a phenomenon called idiopathic CD4 lymphocytopenia. It is common practice for normal ranges for lymphocyte subsets to be derived from samples taken from blood donors. STUDY DESIGN AND METHODS A sample of EDTA blood was taken through the donation line tubing, after donation from 565 blood donors in Sydney, Australia, who were selected from a range of age groups. An additional 12 donors provided a predonation sample as well as a postdonation sample. Hematologic assays were performed on two analyzers. Samples were stained for CD3, CD4, CD8, CD19, and CD56 and analyzed on a flow cytometer. RESULTS Three donors were found to have absolute CD3+CD4+ counts < 300 cells per microL. The percentage of CD3+CD4+ cells was found to increase with age. Both the percentage and the absolute count of CD3+CD8+ cells decreased with age, which resulted in an increased CD4:CD8 ratio with age. Men had consistently higher absolute counts of CD3-CD56+ cells than women. The 12 additional donors all had greater percentages of CD3+CD4+ cells and lower absolute counts for CD3+, CD3+CD4+, CD3+CD8+, CD19+ and CD3-CD56+ cells after donation than they had before donation (p < 0.001). CONCLUSION It is not satisfactory to base normal ranges for lymphocyte subsets on donor blood, from which the blood sample has been obtained after donation.
Collapse
Affiliation(s)
- J A Bryant
- New South Wales Red Cross Blood Transfusion Service, Sydney, Australia
| | | | | | | | | | | | | |
Collapse
|
43
|
Abstract
One hundred and four IgG monoclonal antibodies with specificity within the Rh Blood Group System were evaluated by flow cytometry as part of the Third International Workshop. Standardisation of data to permit interlaboratory comparison of antibody binding was achieved by adherence to a standard red blood cell staining protocol, defined control cells and a standard FITC-labelled antibody. In addition, calibration standards were provided to permit the calculation of Molecules of Equivalent Soluble Fluorochrome (MESF) values from the mean channel fluorescence. For the majority of anti-D antibodies mean MESF values obtained with D positive cells were far higher than with the negative controls (D negative cells), with D variants having intermediate although very varied MESFs. In general MESF values obtained with non anti-D antibodies were less than for the anti-D antibodies although some of the anti-E antibodies were very strong. The highest MESF values were obtained with an anti-CD antibody.
Collapse
Affiliation(s)
- A Fletcher
- NSW Red Cross Blood Transfusion Service, Sydney, Australia
| | | | | |
Collapse
|
44
|
Abstract
The increased susceptibility to homologous complement in paroxysmal nocturnal haemoglobinuria (PNH) is known to be associated with the deficiency of the membrane complement inhibitors CD59 and CD55. Proteases have been used in this study to modify normal human RBC to complement sensitive PNH-like cells. To investigate the protective role of CD59 and CD55, the relationship between the content of CD59 and CD55 and the complement susceptibility of the PNH-like cells has been determined. The differential resistance of the enzyme-treated RBC to complement-mediated injury was measured by acidified serum lysis. Pronase-treated erythrocytes lacked both CD59 and CD55 and were very susceptible to complement-mediated lysis. Papain treatment of RBC reduced the CD55 content but did not affect CD59 and induced slight susceptibility to complement-mediated lysis. Trypsin treatment of RBC destroyed 80% of CD59, had little effect on CD55 (unless incubation was extended) and slightly increased susceptibility to lysis. Thus, partial CD55 and CD59 activity was sufficient to protect cells from complement-mediated lysis. In the reactive lysis assay, anti-CD55 and anti-CD59 induced haemolysis, anti-CD59 having the more pronounced effect. Lysis was enhanced when RBC were treated by both antibodies simultaneously.
Collapse
Affiliation(s)
- F F Yuan
- NSW Red Cross Blood Transfusion Service, Sydney, Australia
| | | | | |
Collapse
|
45
|
Bryant JA, Fletcher A, Yuan FF. Six monoclonal antibodies to the CD59 antigen. Immunohematology 1993; 9:68-73. [PMID: 15946093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
CD59 defines an N-glycosylated glycoprotein expressed on various hemopoietic cells. It is anchored to the cell membrane by a glycosylpbospbatidylinositol linkage and restricts the action of homologous complement. Monoclonal antibodies 2/24, 182, Fib75.1, BRIC 229, MEM-43, and YTH 53.1 were compared by immunoblotting against normal erythrocyte ghosts. All six stained a diffuse band of 17-25 kDa, but BRIC 229 also detected bands at 35 and 80 kDa. 2/24 reacts with all red blood cells (RBCs) tested, including Rhnull; Ob; ii; Ko; FY:-1,-2,-3; JK:-1,-2,-3; S-s-U-; p; CO:-1,-2; Yt(a-); Jr(a-); Vel-; At(a-); Cr(a-); GE:-2,-3; Wr(a+b+ MkMk; Jo(a-); and Lan-. 2-aminoethylisotbiouronium bromide treatment of erythrocytes destroyed blotting and serologic reactivity of all six antibodies. Pronase treatment reduced serologic reactivity and blotting ability of all antibodies except BRlC 229. Reactivity of all six antibodies was reduced with RBCs from paroxysmal nocturnal hemoglobinuria patients. Flow cytometric analysis was used to demonstrate that 182, Fib75.1, BRIC 229, YTH 53.1, and MEM-43 competitively inhibited the binding of 2/24 to RBCs, thus demonstrating that all six antibodies detect epitopes on the same molecule.
Collapse
Affiliation(s)
- J A Bryant
- Flow Cytometry Laboratory, New South Wales Red Cross Blood Transfusion Service, 153 Clarence Street, Sydney, NSW 2000, Australia
| | | | | |
Collapse
|
46
|
Fletcher A, Bryant JA, Gardner B, Judson PA, Spring FA, Parsons SF, Mallinson G, Anstee DJ. New monoclonal antibodies in CD59: use for the analysis of peripheral blood cells from paroxysmal nocturnal haemoglobinuria (PNH) patients and for the quantitation of CD59 on normal and decay accelerating factor (DAF)-deficient erythrocytes. Immunol Suppl 1992; 75:507-12. [PMID: 1374058 PMCID: PMC1384747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
CD59 is a widely expressed cell surface glycosylphosphatidylinositol (GPI)-linked glycoprotein which acts as an inhibitor of the assembly of the membrane attack complex of autologous complement. Four new monoclonal antibodies to CD59 (2/24, 1B2, BRIC 229, BRIC 257) are described. Competitive binding experiments using these antibodies, two known CD59 antibodies (MEM-43, YTH 53.1) and a previously described antibody LICR-LON-Fib75.1 demonstrated that all seven antibodies see related epitopes on human erythrocyte CD59. In common with other GPI-linked proteins, CD59 (as defined by antibody 2/24) was sensitive to treatment with phosphatidylinositol-specific phospholipase C (PI-PLC) on lymphocytes and monocytes but not on erythrocytes. Flow cytometric analysis using antibody 2/24 identified two populations (CD59 positive and CD59 deficient) of lymphocytes, monocytes and erythrocytes in peripheral blood from a patient with paroxysmal nocturnal haemoglobinuria (PNH). The abundance of CD59 on normal erythrocytes was determined as 21,000 copies/cell when radioiodinated BRIC 229 was used. Other CD59 antibodies gave values of 10,000 (IF5) and 15,000 (2/24) against the same target cells. Radioiodinated Fab fragments of BRIC 229 gave a value of 39,000 copies/cell. Erythrocytes from two individuals with a rare inherited deficiency of decay accelerating factor (DAF), known as the Inab phenotype, expressed normal levels of CD59.
Collapse
Affiliation(s)
- A Fletcher
- Australian Red Cross Society, New South Wales Division, Blood Transfusion Service, Sydney
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Harker CL, Mullineaux PM, Bryant JA, Maule AJ. Detection of CaMV gene I and gene VI protein products in vivo using antisera raised to COOH-terminal β-galactosidase fusion proteins. Plant Mol Biol 1987; 8:275-287. [PMID: 24301131 DOI: 10.1007/bf00015035] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/1986] [Revised: 10/15/1986] [Accepted: 12/01/1986] [Indexed: 06/02/2023]
Abstract
Specific antisera were prepared to the inclusion body protein (gene VI product) and the gene I product of cauliflower mosaic virus (CaMV). Translational fusions between the lacZ gene and gene VI or gene I were constructed by cloning the relevant DNA fragments into the expression vectors pUR290, pUR291 or pUR292. Large amounts of fusion protein were synthesized when the inserted DNA fragment was in frame with the lacZ gene of the expression vector. These fusion proteins were used to raise specific antisera to gene VI and gene I proteins of CaMV. Antiserum to the gene VI product detected a range of proteins in crude extracts and in a subcellular fraction enriched for virus inclusion bodies. This range of proteins was further shown to be related to gene VI by Staphylococcus aureus V8 partial proteolysis. Antiserum to the gene I product detected viral specific proteins of 46, 42 and 38 K in preparations of CaMV replication complexes from infected plants but not in any other subcellular fraction.
Collapse
Affiliation(s)
- C L Harker
- John Innes Institute, Colney Lane, NR4 7UH, Norwich, UK
| | | | | | | |
Collapse
|
48
|
Robinow M, Reynolds JF, FitzGerald J, Bryant JA. Hemifacial microsomia, ipsilateral facial palsy, and malformed auricle in two families: an autosomal dominant malformation. Am J Med Genet Suppl 1986; 2:129-33. [PMID: 3146282 DOI: 10.1002/ajmg.1320250616] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hemifacial microsomia, ipsilateral facial palsy and anomalies of the auricle were observed in father and son in two families. This combination of anomalies is a causally heterogeneous developmental field defect which may occur rarely as an autosomal dominant trait.
Collapse
Affiliation(s)
- M Robinow
- Department of Pediatrics, Wright State University School of Medicine, Dayton, Ohio
| | | | | | | |
Collapse
|
49
|
Thomas CM, Hull R, Bryant JA, Maule AJ. Isolation of a fraction from cauliflower mosaic virus-infected protoplasts which is active in the synthesis of (+) and (-) strand viral DNA and reverse transcription of primed RNA templates. Nucleic Acids Res 1985; 13:4557-76. [PMID: 2409536 PMCID: PMC321806 DOI: 10.1093/nar/13.12.4557] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sub-cellular fractions, isolated from cauliflower mosaic virus (CaMV)-infected turnip protoplasts, are capable of synthesising CaMV DNA in vitro on an endogenous template and of reverse transcribing oligo dT-primed cowpea mosaic virus RNA. The activity was not detected in mock-inoculated protoplasts. In vitro-labelled DNA hybridized to single-stranded M13 clones complementary to the putative origins of (-) and (+) strand CaMV DNA synthesis and to restriction endonuclease fragments encompassing more than 90% of the CaMV genome. The synthesis of (-) and (+) strand DNA appeared asymmetric. The template(s) for in vitro CaMV DNA synthesis are in a partially nuclease-resistant form. Fractions capable of in vitro CaMV DNA synthesis contained CaMV RNA both heterogeneous and as discrete species; they also contained a range of different sizes of CaMV DNA. Several lines of evidence indicate that this range of in vitro-labelled CaMV DNA, extending from 0.6kb to 8.0kb in length, represents elongating (-) strand DNA. These are discussed in relation to their role as possible replicative intermediates.
Collapse
|
50
|
Francis D, Davies ND, Bryant JA, Hughes SG, Sibson DR, Fitchett PN. Effects of psoralen on replicon size and mean rate of DNA synthesis in partially synchronized cells of Pisum sativum L. Exp Cell Res 1985; 158:500-8. [PMID: 4007063 DOI: 10.1016/0014-4827(85)90473-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have examined by fibre autoradiography the spacing of replicons in pea root meristems during synchronized entry into S phase from arrest at the G1/S boundary. Pretreatment with the DNA cross-linking agent, psoralen, produces a marked shortening of replicon spacing, suggesting that premature arrest of the replication fork results in the recruitment of additional initiation points within a given replicon family. This is discussed in relation to models for the control of DNA replication.
Collapse
|