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Zhang J, Jiang X, Shi G, Zhang H, Hu K, Wu D, Shao J, Liu T, Wang T, Wang C. Effect of the Pulsatilla decoction n-butanol extract on vulvovaginal candidiasis caused by Candida glabrata and on its virulence factors. Fitoterapia 2024; 173:105825. [PMID: 38219843 DOI: 10.1016/j.fitote.2024.105825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 01/16/2024]
Abstract
Vulvovaginal candidiasis (VVC) caused by Candida glabrata (C. glabrata) is more persistent and resistant to treatment than when caused by Candida albicans (C. albicans) and has been on the rise in recent years. The n-butanol extract of Pulsatilla Decoction (BEPD) has been shown to be effective in treating VVC caused by C. glabrata, but the underlying mechanism of action remains unclear. In this study, the experimenter conducted in vitro and in vivo experiments to explore the effects of BEPD on the virulence factors of C. glabrata, as well as its efficacy, with a focus on possible immunological mechanism in VVC caused by C. glabrata. The contents of Anemoside B4, Epiberberine, Berberine, Aesculin, Aesculetin, Phellodendrine and Jatrorrhizine in BEPD, detected by high-performance liquid chromatography, were 31,736.64, 13,529.66, 105,143.72, 19,406.20, 4952.67, 10,317.03, 2489.93 μg/g, respectively. In vitro experiments indicated that BEPD moderately inhibited the growth of C. glabrata, its adhesion, and biofilm formation, and affected the expression of efflux transporters in the biofilm state. In vivo experiments demonstrated that BEPD significantly reduced vaginal inflammatory manifestation and the release of proinflammatory cytokines and LDH in mice with VVC caused by C. glabrata. Moreover, it inhibited the Phosphorylation of EGFR, ERK, P38, P65, and C-Fos proteins. The results suggested that although BEPD moderately inhibits the growth and virulence factors of C. glabrata in vitro, it can significantly reduce vaginal inflammation by down-regulating the EGFR/MAPK signaling pathway in mice with VVC infected by C. glabrata.
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Affiliation(s)
- Jiaping Zhang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China; College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China
| | - Xiaojuan Jiang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Gaoxiang Shi
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Hao Zhang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Kaifan Hu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Daqiang Wu
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Jing Shao
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Tingting Liu
- Department of Pharmacy, The First Affiliated Hospital of Anhui Medical University, The Grade 3 Pharmaceutical Chemistry Laboratory of State Administration of Traditional Chinese Medicine, Hefei, China
| | - Tianming Wang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China; College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China.
| | - Changzhong Wang
- Department of Pathogenic Biology and Immunology, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Hefei, China; Institute of Integrated Traditional Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, China.
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Choi J, Lee S, Kim H, Park J. The role of recognition error in the stability of green-beard genes. Evol Lett 2023; 7:157-167. [PMID: 37251589 PMCID: PMC10210436 DOI: 10.1093/evlett/qrad012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 03/17/2023] [Accepted: 03/29/2023] [Indexed: 05/31/2023] Open
Abstract
The empirical examples of the green-beard genes, once a conundrum of evolutionary biology, are accumulating, while theoretical analyses of this topic are occasional compared to those concerning (narrow-sense) kin selection. In particular, the recognition error of the green-beard effect that the cooperator fails to accurately recognize the other cooperators or defectors is readily found in numerous green-beard genes. To our knowledge, however, no model up to date has taken that effect into account. In this article, we investigated the effect of recognition error on the fitness of the green-beard gene. By employing theories of evolutionary games, our mathematical model predicts that the fitness of the green-beard gene is frequency dependent (frequency of the green-beard gene), which was corroborated by experiments performed with yeast FLO1. The experiment also shows that the cells with the green-beard gene (FLO1) are sturdier under severe stress. We conclude that the low recognition error among the cooperators, the higher reward of cooperation, and the higher cost of defection confer an advantage to the green-beard gene under certain conditions, confirmed by numerical simulation as well. Interestingly, we expect that the recognition error to the defectors may promote the cooperator fitness if the cooperator frequency is low and mutual defection is detrimental. Our ternary approach of mathematical analysis, experiments, and simulation lays the groundwork of the standard model for the green-beard gene that can be generalized to other species.
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Affiliation(s)
- Jibeom Choi
- Corresponding authors: Department of Applied Mathematics, College of Applied Science, Kyung Hee University, Yongin 17104, Republic of Korea.
| | - Seoeun Lee
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyun Kim
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
- Institute of Microbiology, Seoul National University, Seoul, Republic of Korea
| | - Junpyo Park
- Department of Applied Mathematics, College of Applied Science, Kyung Hee University, Yongin 17104, Republic of Korea.
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Lindberg SK, Willsey GG, Mantis NJ. Flagellar-based motility accelerates IgA-mediated agglutination of Salmonella Typhimurium at high bacterial cell densities. Front Immunol 2023; 14:1193855. [PMID: 37275888 PMCID: PMC10232770 DOI: 10.3389/fimmu.2023.1193855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 05/03/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction Secretory IgA (SIgA) protects the intestinal epithelium from enteric pathogens such as Salmonella enterica serovar Typhimurium (STm) through a process known as immune exclusion, where invading bacteria are aggregated via antibody cross-linking, encased in mucus, and then cleared from the intestinal tract via peristalsis. At high cell densities, the STm aggregates form a tightly packed network that is reminiscent of early bacterial biofilms. However, the underlying mechanism of how SIgA mediates this transition from a motile and invasive state to an avirulent sessile state in STm is currently unknown. Methods In this report, we developed and validated a methodology known as the "snow globe" assay to enable real-time imaging and quantification of STm agglutination by the mouse monoclonal IgA Sal4. Results We observed that agglutination in the snow globe assay was dose-dependent, antigen-specific, and influenced by antibody isotype. We determined that flagellar-based motility was a prerequisite for rapid onset of agglutination, even at high cell densities where cell-cell contacts are expected to be frequent. We also investigated the roles of individual cyclic-di-GMP metabolizing enzymes previously implicated in motility and biofilm formation in Sal4 IgA-mediated agglutination. Discussion Taken together, our results demonstrate that IgA-mediated agglutination is a dynamic process influenced by bacterial motility and cell-cell collisions. We conclude that the snow globe assay is a viable platform to further decipher the molecular and genetic determinants that drive this interaction.
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Affiliation(s)
- Samantha K. Lindberg
- Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY, United States
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, United States
| | - Graham G. Willsey
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, United States
| | - Nicholas J. Mantis
- Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY, United States
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, United States
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4
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Belpaire TER, Pešek J, Lories B, Verstrepen KJ, Steenackers HP, Ramon H, Smeets B. Permissive aggregative group formation favors coexistence between cooperators and defectors in yeast. THE ISME JOURNAL 2022; 16:2305-2312. [PMID: 35778439 PMCID: PMC9477849 DOI: 10.1038/s41396-022-01275-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 06/08/2022] [Accepted: 06/16/2022] [Indexed: 06/01/2023]
Abstract
In Saccharomyces cerevisiae, the FLO1 gene encodes flocculins that lead to formation of multicellular flocs, that offer protection to the constituent cells. Flo1p was found to preferentially bind to fellow cooperators compared to defectors lacking FLO1 expression, enriching cooperators within the flocs. Given this dual function in cooperation and kin recognition, FLO1 has been termed a "green beard gene". Because of the heterophilic nature of the Flo1p bond however, we hypothesize that kin recognition is permissive and depends on the relative stability of the FLO1+/flo1- versus FLO1+/FLO1+ detachment force F. We combine single-cell measurements of adhesion, individual cell-based simulations of cluster formation, and in vitro flocculation to study the impact of relative bond stability on the evolutionary stability of cooperation. We identify a trade-off between both aspects of the green beard mechanism, with reduced relative bond stability leading to increased kin recognition at the expense of cooperative benefits. We show that the fitness of FLO1 cooperators decreases as their frequency in the population increases, arising from the observed permissive character (F+- = 0.5 F++) of the Flo1p bond. Considering the costs associated with FLO1 expression, this asymmetric selection often results in a stable coexistence between cooperators and defectors.
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Affiliation(s)
- Tom E R Belpaire
- Division of Mechatronics, Biostatistics, and Sensors, KU Leuven, 3001, Leuven, Belgium.
- Centre for Microbial and Plant Genetics, KU Leuven, 3001, Leuven, Belgium.
| | - Jiří Pešek
- Team SIMBIOTX, Inria Saclay, 91120, Palaiseau, France
| | - Bram Lories
- Centre for Microbial and Plant Genetics, KU Leuven, 3001, Leuven, Belgium
| | - Kevin J Verstrepen
- Centre for Microbial and Plant Genetics, KU Leuven, 3001, Leuven, Belgium
- Laboratory of Systems Biology, VIB-KU Leuven Center for Microbiology, 3001, Leuven, Belgium
| | - Hans P Steenackers
- Centre for Microbial and Plant Genetics, KU Leuven, 3001, Leuven, Belgium
| | - Herman Ramon
- Division of Mechatronics, Biostatistics, and Sensors, KU Leuven, 3001, Leuven, Belgium
| | - Bart Smeets
- Division of Mechatronics, Biostatistics, and Sensors, KU Leuven, 3001, Leuven, Belgium
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5
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Pan J, Kmieciak T, Liu YT, Wildenradt M, Chen YS, Zhao Y. Quantifying molecular- to cellular-level forces in living cells. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2021; 54:483001. [PMID: 34866655 PMCID: PMC8635116 DOI: 10.1088/1361-6463/ac2170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Mechanical cues have been suggested to play an important role in cell functions and cell fate determination, however, such physical quantities are challenging to directly measure in living cells with single molecule sensitivity and resolution. In this review, we focus on two main technologies that are promising in probing forces at the single molecule level. We review their theoretical fundamentals, recent technical advancements, and future directions, tailored specifically for interrogating mechanosensitive molecules in live cells.
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Affiliation(s)
- Jason Pan
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - Tommy Kmieciak
- Department of Engineering Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - Yen-Ting Liu
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - Matthew Wildenradt
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - Yun-Sheng Chen
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
| | - Yang Zhao
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States of America
- Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, 208 N. Wright Street, Urbana, IL 61801, United States of America
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6
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Wada M, Nomura T. Direct measurement of adhesion force between a yeast cell and a lactic acid bacterium cell with atomic force microscopy. J Biosci Bioeng 2021; 133:155-160. [PMID: 34863625 DOI: 10.1016/j.jbiosc.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/04/2021] [Accepted: 11/11/2021] [Indexed: 11/28/2022]
Abstract
Lactic acid bacteria (LAB) and yeast coexist by providing nutrients as substrates for each other. LAB and yeast cells aggregate via specific interactions between mannose on the yeast surface and the mannose-binding protein (MBP) on the LAB surface. In addition to specific interactions via cell surface proteins, there are also nonspecific interactions related to microbial coaggregation; the extent of their contributions is not clear. Here, microbial coaggregation of yeast and LAB cells was investigated from the view point of particle technology. DLVO theory and thermodynamic approaches predicted that thermodynamically stable coaggregates are not formed because no hydrophobic interaction acts between yeast and LAB. In contrast, optical microscopy revealed that yeast with mannose and LAB with MBP were formed submillimeter-sized coaggregates, whereas deficient strains of yeast and/or LAB were dispersed. Single-cell force spectroscopy revealed that the median adhesion forces were less than 100 pN for all combinations of yeast and LAB. However, some of the adhesion forces between yeast with mannose and LAB with MBP were greater than 400 pN. Furthermore, in the presence of a microbial coaggregation inhibitor, coaggregation of yeast with mannose and LAB with MBP was suppressed, and the adhesion forces were less than 300 pN. These results indicate that the specific interaction rather than the nonspecific interactions acted between mannose on the yeast and the MBP on the LAB formed submillimeter-sized small aggregates. Understanding the contribution of predominant cell-cell interactions may help control microbial behavior in biotechnology.
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Affiliation(s)
- Masayuki Wada
- Department of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Toshiyuki Nomura
- Department of Chemical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
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7
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Willaert RG, Kayacan Y, Devreese B. The Flo Adhesin Family. Pathogens 2021; 10:pathogens10111397. [PMID: 34832553 PMCID: PMC8621652 DOI: 10.3390/pathogens10111397] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 12/14/2022] Open
Abstract
The first step in the infection of fungal pathogens in humans is the adhesion of the pathogen to host tissue cells or abiotic surfaces such as catheters and implants. One of the main players involved in this are the expressed cell wall adhesins. Here, we review the Flo adhesin family and their involvement in the adhesion of these yeasts during human infections. Firstly, we redefined the Flo adhesin family based on the domain architectures that are present in the Flo adhesins and their functions, and set up a new classification of Flo adhesins. Next, the structure, function, and adhesion mechanisms of the Flo adhesins whose structure has been solved are discussed in detail. Finally, we identified from Pfam database datamining yeasts that could express Flo adhesins and are encountered in human infections and their adhesin architectures. These yeasts are discussed in relation to their adhesion characteristics and involvement in infections.
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Affiliation(s)
- Ronnie G. Willaert
- Research Group Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Correspondence: ; Tel.: +32-2629-1846
| | - Yeseren Kayacan
- Research Group Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Bart Devreese
- Alliance Research Group VUB-UGent NanoMicrobiology (NAMI), 1050 Brussels, Belgium;
- International Joint Research Group VUB-EPFL NanoBiotechnology & NanoMedicine (NANO), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium
- Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Laboratory for Microbiology, Gent University (UGent), 9000 Gent, Belgium
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Lipke PN, Mathelié-Guinlet M, Viljoen A, Dufrêne YF. A New Function for Amyloid-Like Interactions: Cross-Beta Aggregates of Adhesins form Cell-to-Cell Bonds. Pathogens 2021; 10:pathogens10081013. [PMID: 34451476 PMCID: PMC8398270 DOI: 10.3390/pathogens10081013] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 12/30/2022] Open
Abstract
Amyloid structures assemble through a repeating type of bonding called "cross-β", in which identical sequences in many protein molecules form β-sheets that interdigitate through side chain interactions. We review the structural characteristics of such bonds. Single cell force microscopy (SCFM) shows that yeast expressing Als5 adhesin from Candida albicans demonstrate the empirical characteristics of cross-β interactions. These properties include affinity for amyloid-binding dyes, birefringence, critical concentration dependence, repeating structure, and inhibition by anti-amyloid agents. We present a model for how cross-β bonds form in trans between two adhering cells. These characteristics also apply to other fungal adhesins, so the mechanism appears to be an example of a new type of cell-cell adhesion.
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Affiliation(s)
- Peter N. Lipke
- Biology Department, Brooklyn College of City University of New York, 2900 Bedford Avenue, Brooklyn, NY 11210, USA
- Correspondence: ; Tel.: +1-(917)-696-4862
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (M.M.-G.); (A.V.); (Y.F.D.)
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (M.M.-G.); (A.V.); (Y.F.D.)
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium; (M.M.-G.); (A.V.); (Y.F.D.)
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9
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Engineered cardiac tissue microsphere production through direct differentiation of hydrogel-encapsulated human pluripotent stem cells. Biomaterials 2021; 274:120818. [PMID: 34023620 DOI: 10.1016/j.biomaterials.2021.120818] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 03/02/2021] [Accepted: 04/07/2021] [Indexed: 02/06/2023]
Abstract
Engineered cardiac tissues that can be directly produced from human induced pluripotent stem cells (hiPSCs) in scalable, suspension culture systems are needed to meet the demands of cardiac regenerative medicine. Here, we demonstrate successful production of functional cardiac tissue microspheres through direct differentiation of hydrogel encapsulated hiPSCs. To form the microspheres, hiPSCs were suspended within the photocrosslinkable biomaterial, PEG-fibrinogen (25 million cells/mL), and encapsulated at a rate of 420,000 cells/minute using a custom microfluidic system. Even at this high cell density and rapid production rate, high intra-batch and batch-to-batch reproducibility was achieved. Following microsphere formation, hiPSCs maintained high cell viability and continued to grow within and beyond the original PEG-fibrinogen matrix. These initially soft microspheres (<250 Pa) supported efficient cardiac differentiation; spontaneous contractions initiated by differentiation day 8, and the microspheres contained >75% cardiomyocytes (CMs). CMs responded appropriately to pharmacological stimuli and exhibited 1:1 capture up to 6.0 Hz when electrically paced. Over time, cells formed cell-cell junctions and aligned myofibril fibers; engineered cardiac microspheres were maintained in culture over 3 years. The capability to rapidly generate uniform cardiac microsphere tissues is critical for advancing downstream applications including biomanufacturing, multi-well plate drug screening, and injection-based regenerative therapies.
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10
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Beaussart A, Feuillie C, El-Kirat-Chatel S. The microbial adhesive arsenal deciphered by atomic force microscopy. NANOSCALE 2020; 12:23885-23896. [PMID: 33289756 DOI: 10.1039/d0nr07492f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Microbes employ a variety of strategies to adhere to abiotic and biotic surfaces, as well as host cells. In addition to their surface physicochemical properties (e.g. charge, hydrophobic balance), microbes produce appendages (e.g. pili, fimbriae, flagella) and express adhesion proteins embedded in the cell wall or cell membrane, with adhesive domains targeting specific ligands or chemical properties. Atomic force microscopy (AFM) is perfectly suited to deciphering the adhesive properties of microbial cells. Notably, AFM imaging has revealed the cell wall topographical organization of live cells at unprecedented resolution, and AFM has a dual capability to probe adhesion at the single-cell and single-molecule levels. AFM is thus a powerful tool for unravelling the molecular mechanisms of microbial adhesion at scales ranging from individual molecular interactions to the behaviours of entire cells. In this review, we cover some of the major breakthroughs facilitated by AFM in deciphering the microbial adhesive arsenal, including the exciting development of anti-adhesive strategies.
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11
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Liu Y, Sokolov I, Dokukin ME, Xiong Y, Peng P. Can AFM be used to measure absolute values of Young's modulus of nanocomposite materials down to the nanoscale? NANOSCALE 2020; 12:12432-12443. [PMID: 32495797 DOI: 10.1039/d0nr02314k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
At present, a technique potentially capable of measuring values of Young's modulus at the nanoscale is atomic force microscopy (AFM) working in the indentation mode. However, the question if AFM indentation data can be translated into absolute values of the modulus is not well-studied as yet, in particular, for the most interesting case of stiff nanocomposite materials. Here we investigate this question. A special sample of nanocomposite material, shale rock, was used, which is relatively homogeneous at the multi-micron scale. Two AFM modes, force-volume and PeakForce QNM were used in this study. The nanoindentation technique was used as a control benchmark for the measurement of effective Young's modulus of the shale sample. The indentation rate was carefully controlled. To ensure the self-consistency of the mechanical model used to analyze AFM data, the model was modified to take into account the presence of the surface roughness. We found excellent agreement between the average values of effective Young's modulus calculated within AFM and the nanoindenter benchmark method. At the same time, the softest and hardest areas of the sample were seen only with AFM.
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Affiliation(s)
- Yuke Liu
- Department of Mechanical Engineering, Tufts University, Medford, MA, USA.
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12
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Viela F, Mathelié-Guinlet M, Viljoen A, Dufrêne YF. What makes bacterial pathogens so sticky? Mol Microbiol 2020; 113:683-690. [PMID: 31916325 DOI: 10.1111/mmi.14448] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/06/2020] [Indexed: 01/06/2023]
Abstract
Pathogenic bacteria use a variety of cell surface adhesins to promote binding to host tissues and protein-coated biomaterials, as well as cell-cell aggregation. These cellular interactions represent the first essential step that leads to host colonization and infection. Atomic force microscopy (AFM) has greatly contributed to increase our understanding of the specific interactions at play during microbial adhesion, down to the single-molecule level. A key asset of AFM is that adhesive interactions are studied under mechanical force, which is highly relevant as surface-attached pathogens are often exposed to physical stresses in the human body. These studies have identified sophisticated binding mechanisms in adhesins, which represent promising new targets for antiadhesion therapy.
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Affiliation(s)
- Felipe Viela
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Marion Mathelié-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Albertus Viljoen
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium.,Walloon Excellence in Life sciences and Biotechnology (WELBIO), Wavre, Belgium
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13
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Yumiyama S, Kato S, Konishi Y, Nomura T. Direct measurement of interaction forces between a yeast cell and a microbubble using atomic force microscopy. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.123963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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14
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Beaussart A, El-Kirat-Chatel S. Microbial adhesion and ultrastructure from the single-molecule to the single-cell levels by Atomic Force Microscopy. Cell Surf 2019; 5:100031. [PMID: 32743147 PMCID: PMC7389263 DOI: 10.1016/j.tcsw.2019.100031] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 12/29/2022] Open
Abstract
In the last decades, atomic force microscopy (AFM) has evolved towards an accurate and lasting tool to study the surface of living cells in physiological conditions. Through imaging, single-molecule force spectroscopy and single-cell force spectroscopy modes, AFM allows to decipher at multiple scales the morphology and the molecular interactions taking place at the cell surface. Applied to microbiology, these approaches have been used to elucidate biophysical properties of biomolecules and to directly link the molecular structures to their function. In this review, we describe the main methods developed for AFM-based microbial surface analysis that we illustrate with examples of molecular mechanisms unravelled with unprecedented resolution.
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15
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Sumikawa K, Kosaka T, Mayahara N, Matsutani M, Udo K, Yamada M. An Aggregation-defective Mutant of Methanothermobacter sp. CaT2 Reveals Unique Protein-dependent Aggregation. Microbes Environ 2019; 34:244-251. [PMID: 31189768 PMCID: PMC6759345 DOI: 10.1264/jsme2.me19014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The thermophilic hydrogenotrophic methanogen, Methanothermobacter sp. CaT2, which possesses an extracellular sugar layer, commonly aggregates by itself or with other microorganisms. To elucidate the molecular mechanisms responsible for this aggregation, the aggregation-defective mutant, CLA160, was isolated. Optical and electron microscopy observations revealed that the mutant exhibited a significant reduction in aggregation. Genomic sequencing showed that CLA160 has a single point mutation, causing a nonsense mutation in MTCT_1020, which encodes a hypothetical protein. Motif and domain analyses indicated that the hypothetical protein bears two membrane-spanning segments at the N- and C-terminal regions and a large middle repeat-containing region. The results of a bioinformatic analysis suggested that the first middle region (RII) of the protein or the whole structure is responsible for the function of the product of MTCT_1020 in the aggregation of CaT2. A treatment with proteinase K suppressed sedimentation in CaT2, indicating a reduction in aggregation, with almost no effect on sedimentation in CLA160. The addition of Ca2+ or Mg2+ ions enhanced sedimentation in CaT2, whereas a DNase treatment had no effect on sedimentation in either strain. These results suggest that the hypothetical protein encoded by MTCT_1020 plays a key role as a membrane-bound adhesion protein in the aggregation of CaT2, which is enhanced by the addition of Ca2+ or Mg2+ ions.
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Affiliation(s)
- Kana Sumikawa
- Applied Molecular Bioscience, Graduates School of Medicine, Yamaguchi University
| | - Tomoyuki Kosaka
- Department of Biological Chemistry, College of Agriculture, Graduates School of Science and Technology for Innovation, Yamaguchi University.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University
| | - Noriaki Mayahara
- Applied Molecular Bioscience, Graduates School of Medicine, Yamaguchi University
| | - Minenosuke Matsutani
- Department of Biological Chemistry, College of Agriculture, Graduates School of Science and Technology for Innovation, Yamaguchi University
| | - Koichi Udo
- Science Research Center, Yamaguchi University
| | - Mamoru Yamada
- Applied Molecular Bioscience, Graduates School of Medicine, Yamaguchi University.,Department of Biological Chemistry, College of Agriculture, Graduates School of Science and Technology for Innovation, Yamaguchi University.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University
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16
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Rowlands H, Shaban K, Foster B, Proteau Y, Yankulov K. Histone chaperones and the Rrm3p helicase regulate flocculation in S. cerevisiae. Epigenetics Chromatin 2019; 12:56. [PMID: 31547833 PMCID: PMC6757361 DOI: 10.1186/s13072-019-0303-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 09/03/2019] [Indexed: 12/16/2022] Open
Abstract
Background Biofilm formation or flocculation is a major phenotype in wild type budding yeasts but rarely seen in laboratory yeast strains. Here, we analysed flocculation phenotypes and the expression of FLO genes in laboratory strains with various genetic backgrounds. Results We show that mutations in histone chaperones, the helicase RRM3 and the Histone Deacetylase HDA1 de-repress the FLO genes and partially reconstitute flocculation. We demonstrate that the loss of repression correlates to elevated expression of several FLO genes, to increased acetylation of histones at the promoter of FLO1 and to variegated expression of FLO11. We show that these effects are related to the activity of CAF-1 at the replication forks. We also demonstrate that nitrogen starvation or inhibition of histone deacetylases do not produce flocculation in W303 and BY4742 strains but do so in strains compromised for chromatin maintenance. Finally, we correlate the de-repression of FLO genes to the loss of silencing at the subtelomeric and mating type gene loci. Conclusions We conclude that the deregulation of chromatin maintenance and transmission is sufficient to reconstitute flocculation in laboratory yeast strains. Consequently, we propose that a gain in epigenetic silencing is a major contributing factor for the loss of flocculation phenotypes in these strains. We suggest that flocculation in yeasts provides an excellent model for addressing the challenging issue of how epigenetic mechanisms contribute to evolution.
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Affiliation(s)
- Hollie Rowlands
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Barret Foster
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Yannic Proteau
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada.
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17
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Ogawa M, Bisson LF, García-Martínez T, Mauricio JC, Moreno-García J. New insights on yeast and filamentous fungus adhesion in a natural co-immobilization system: proposed advances and applications in wine industry. Appl Microbiol Biotechnol 2019; 103:4723-4731. [PMID: 31079167 DOI: 10.1007/s00253-019-09870-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/18/2019] [Accepted: 04/24/2019] [Indexed: 11/29/2022]
Abstract
Fungi possess extraordinary strength in attachment to biotic and abiotic surfaces. This review focuses on adhesion mechanisms of yeast and filamentous fungi and the proposed combination of the adhesive forces of both organisms in an immobilization system called yeast biocapsules, whereby Saccharomyces cerevisiae cells are attached to the hyphae of Penicillium chrysogenum. The natural adherent properties of each organism, one multicellular and another unicellular, allow yeast to be fixated securely on the filamentous fungi and complete alcoholic fermentation. Following alcoholic fermentation, the hyphae become an inert support for yeast cells while maintaining shape and integrity. Biocapsules have been used successfully in both wine and bioethanol production. Investigation of the potential genes involved in fungal-yeast fusion suggests that natural hydrophobic interactions of both organisms play a major role. Analysis of the possible mechanisms involved in fungus and yeast adhesion, future perspectives on improving yeast immobilization, and proposed applications of the biocapsules are explored.
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Affiliation(s)
- Minami Ogawa
- Department of Microbiology, University of Córdoba, Córdoba, Spain.,Department of Viticulture and Enology, University of California, Davis, Davis, CA, USA
| | - Linda F Bisson
- Department of Viticulture and Enology, University of California, Davis, Davis, CA, USA
| | | | - Juan C Mauricio
- Department of Microbiology, University of Córdoba, Córdoba, Spain
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18
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Engineered Stochastic Adhesion Between Microbes as a Protection Mechanism Against Environmental Stress. Cell Mol Bioeng 2018; 11:367-382. [PMID: 31719890 DOI: 10.1007/s12195-018-0552-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 08/29/2018] [Indexed: 01/14/2023] Open
Abstract
Introduction Microbes aggregate when they display adhesive proteins on their outer membrane surfaces, which then form bridges between microbes. Aggregation protects the inner microbes from harsh environmental conditions such as high concentrations of antibiotics, high salt conditions, and fluctuations in pH. The protective effects of microbial aggregation make it an attractive target for improving the ability of probiotic strains to persist in the gut environment. However, it remains challenging to achieve synthetic microbial aggregation using natural adhesive proteins because these proteins frequently mediate microbial virulence. Objectives Construction of synthetic proteins that mediate aggregation between microbes to enhance the survival of cells delivered to stressful environments. Methods We construct synthetic adhesins by fusing adhesive protein domains to surface display peptides. The resulting aggregated populations of bacteria are characterized using immunofluorescence, microscopy, flow cytometry, and quantification of colony forming units. Results We assemble a series of synthetic adhesins, demonstrate their display on the outer membrane of Escherichia coli, and show that they mediate bacterial aggregation. Further engineering of the size and motif composition of the adhesive domain shows that principles from natural adhesins can be applied to our synthetic adhesins. Finally, we show that aggregation allows E. coli cells to resist treatment with antimicrobial peptides and survive inside the gut of Caenorhabditis elegans. Conclusions Our results demonstrate that synthetic aggregation can allow bacteria to resist biocidal environmental conditions. Synthetic adhesins may be used to facilitate microbial colonization of previously inaccessible environmental niches, either in remote natural environments or inside living organisms.
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19
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Lipke PN. What We Do Not Know about Fungal Cell Adhesion Molecules. J Fungi (Basel) 2018; 4:jof4020059. [PMID: 29772751 PMCID: PMC6023273 DOI: 10.3390/jof4020059] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/27/2018] [Accepted: 05/10/2018] [Indexed: 12/16/2022] Open
Abstract
There has been extensive research on structure and function of fungal cell adhesion molecules, but the most of the work has been about adhesins in Candida albicans and Saccharomyces cerevisiae. These yeasts are members of a single ascomycete order, and adhesion molecules from the six other fungal phyla are only sparsely described in the literature. In these other phyla, most of the research is at the cellular level, rather than at the molecular level, so there has been little characterization of the adhesion molecules themselves. A catalog of known adhesins shows some common features: high Ser/Thr content, tandem repeats, N- and O-glycosylations, GPI anchors, dibasic sequence motifs, and potential amyloid-forming sequences. However, none of these features is universal. Known ligands include proteins and glycans on homologous cells and host cells. Existing and novel tools can exploit the availability of genome sequences to identify and characterize new fungal adhesins. These include bioinformatics tools and well-established yeast surface display models, which could be coupled with an adhesion substrate array. Thus, new knowledge could be exploited to answer key questions in fungal ecology, animal and plant pathogenesis, and roles of biofilms in infection and biomass turnover.
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Affiliation(s)
- Peter N Lipke
- Biology Department, Brooklyn College, City University of New York, Brooklyn, NY 11210, USA.
- The Graduate Center, City University of New York, New York, NY 10016, USA.
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Amyloid-Like β-Aggregates as Force-Sensitive Switches in Fungal Biofilms and Infections. Microbiol Mol Biol Rev 2017; 82:82/1/e00035-17. [PMID: 29187516 DOI: 10.1128/mmbr.00035-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cellular aggregation is an essential step in the formation of biofilms, which promote fungal survival and persistence in hosts. In many of the known yeast cell adhesion proteins, there are amino acid sequences predicted to form amyloid-like β-aggregates. These sequences mediate amyloid formation in vitro. In vivo, these sequences mediate a phase transition from a disordered state to a partially ordered state to create patches of adhesins on the cell surface. These β-aggregated protein patches are called adhesin nanodomains, and their presence greatly increases and strengthens cell-cell interactions in fungal cell aggregation. Nanodomain formation is slow (with molecular response in minutes and the consequences being evident for hours), and strong interactions lead to enhanced biofilm formation. Unique among functional amyloids, fungal adhesin β-aggregation can be triggered by the application of physical shear force, leading to cellular responses to flow-induced stress and the formation of robust biofilms that persist under flow. Bioinformatics analysis suggests that this phenomenon may be widespread. Analysis of fungal abscesses shows the presence of surface amyloids in situ, a finding which supports the idea that phase changes to an amyloid-like state occur in vivo. The amyloid-coated fungi bind the damage-associated molecular pattern receptor serum amyloid P component, and there may be a consequential modulation of innate immune responses to the fungi. Structural data now suggest mechanisms for the force-mediated induction of the phase change. We summarize and discuss evidence that the sequences function as triggers for protein aggregation and subsequent cellular aggregation, both in vitro and in vivo.
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21
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Li M, Dang D, Xi N, Wang Y, Liu L. Nanoscale imaging and force probing of biomolecular systems using atomic force microscopy: from single molecules to living cells. NANOSCALE 2017; 9:17643-17666. [PMID: 29135007 DOI: 10.1039/c7nr07023c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Due to the lack of adequate tools for observation, native molecular behaviors at the nanoscale have been poorly understood. The advent of atomic force microscopy (AFM) provides an exciting instrument for investigating physiological processes on individual living cells with molecular resolution, which attracts the attention of worldwide researchers. In the past few decades, AFM has been widely utilized to investigate molecular activities on diverse biological interfaces, and the performances and functions of AFM have also been continuously improved, greatly improving our understanding of the behaviors of single molecules in action and demonstrating the important role of AFM in addressing biological issues with unprecedented spatiotemporal resolution. In this article, we review the related techniques and recent progress about applying AFM to characterize biomolecular systems in situ from single molecules to living cells. The challenges and future directions are also discussed.
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Affiliation(s)
- Mi Li
- State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016, China.
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22
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FLO5 gene controls flocculation phenotype and adhesive properties in a Saccharomyces cerevisiae sparkling wine strain. Sci Rep 2017; 7:10786. [PMID: 28883485 PMCID: PMC5589750 DOI: 10.1038/s41598-017-09990-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/01/2017] [Indexed: 12/13/2022] Open
Abstract
Flocculation is an important feature for yeast survival in adverse conditions. The natural diversity of flocculating genes in Saccharomyces cerevisiae can also be exploited in several biotechnological applications. Flocculation is mainly regulated by the expression of genes belonging to the FLO family. These genes have a similar function, but their specific contribution to flocculation ability is still unclear. In this study, the distribution of FLO1, FLO5 and FLO8 genes in four S. cerevisiae wine strains was investigated. Subsequently, both FLO1 and FLO5 genes were separately deleted in a flocculent S. cerevisiae wine strain. After gene disruption, flocculation ability and agar adhesion were evaluated. FLO1 and FLO5 genes inheritance was also monitored. All strains presented different lengths for FLO1 and FLO5 genes. Results confirm that in S. cerevisiae strain F6789, the FLO5 gene drives flocculation and influences adhesive properties. Flocculation ability monitoring after a cross with a non-flocculent strain revealed that FLO5 is the gene responsible for flocculation development.
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23
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Xiao J, Dufrêne YF. Optical and force nanoscopy in microbiology. Nat Microbiol 2016; 1:16186. [PMID: 27782138 PMCID: PMC5839876 DOI: 10.1038/nmicrobiol.2016.186] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/01/2016] [Indexed: 12/31/2022]
Abstract
Microbial cells have developed sophisticated multicomponent structures and machineries to govern basic cellular processes, such as chromosome segregation, gene expression, cell division, mechanosensing, cell adhesion and biofilm formation. Because of the small cell sizes, subcellular structures have long been difficult to visualize using diffraction-limited light microscopy. During the last three decades, optical and force nanoscopy techniques have been developed to probe intracellular and extracellular structures with unprecedented resolutions, enabling researchers to study their organization, dynamics and interactions in individual cells, at the single-molecule level, from the inside out, and all the way up to cell-cell interactions in microbial communities. In this Review, we discuss the principles, advantages and limitations of the main optical and force nanoscopy techniques available in microbiology, and we highlight some outstanding questions that these new tools may help to answer.
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Affiliation(s)
- Jie Xiao
- Department of Biophysics &Biophysical Chemistry, The Johns Hopkins School of Medicine, 725 N. Wolfe Street, Baltimore, Maryland 21212, USA
| | - Yves F Dufrêne
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
- Walloon Excellence in Life sciences and Biotechnology (WELBIO), Belgium
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Molecular Basis for Strain Variation in the Saccharomyces cerevisiae Adhesin Flo11p. mSphere 2016; 1:mSphere00129-16. [PMID: 27547826 PMCID: PMC4989245 DOI: 10.1128/msphere.00129-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/27/2016] [Indexed: 11/20/2022] Open
Abstract
As a nonmotile organism, Saccharomyces cerevisiae employs the cell surface flocculin Flo11/Muc1 as an important means of adapting to environmental change. However, there is a great deal of strain variation in the expression of Flo11-dependent phenotypes, including flocculation. In this study, we investigated the molecular basis of this strain-specific phenotypic variability. Our data indicate that strain-specific differences in the level of flocculation result from significant sequence differences in the FLO11 alleles and do not depend on quantitative differences in FLO11 expression or on surface hydrophobicity. We further have shown that beads coated with amino-terminal domain peptide bind preferentially to homologous cells. These data show that variability in the structure of the Flo11 adhesion domain may thus be an important determinant of membership in microbial communities and hence may drive selection and evolution. FLO11 encodes a yeast cell wall flocculin that mediates a variety of adhesive phenotypes in Saccharomyces cerevisiae. Flo11p is implicated in many developmental processes, including flocculation, formation of pseudohyphae, agar invasion, and formation of microbial mats and biofilms. However, Flo11p mediates different processes in different yeast strains. To investigate the mechanisms by which FLO11 determines these differences in colony morphology, flocculation, and invasion, we studied gene structure, function, and expression levels. Nonflocculent Saccharomyces cerevisiae Σ1278b cells exhibited significantly higher FLO11 mRNA expression, especially in the stationary phase, than highly flocculent S. cerevisiae var. diastaticus. The two strains varied in cell surface hydrophobicity, and Flo11p contributed significantly to surface hydrophobicity in S. cerevisiae var. diastaticus but not in strain Σ1278b. Sequencing of the FLO11 gene in S. cerevisiae var. diastaticus revealed strain-specific differences, including a 15-amino-acid insertion in the adhesion domain. Flo11p adhesion domains from strain Σ1278b and S. cerevisiae var. diastaticus were expressed and used to coat magnetic beads. The adhesion domain from each strain bound preferentially to homologous cells, and the preferences were independent of the cells in which the adhesion domains were produced. These results are consistent with the idea that strain-specific variations in the amino acid sequences in the adhesion domains cause different Flo11p flocculation activities. The results also imply that strain-specific differences in expression levels, posttranslational modifications, and allelic differences outside the adhesion domains have little effect on flocculation. IMPORTANCE As a nonmotile organism, Saccharomyces cerevisiae employs the cell surface flocculin Flo11/Muc1 as an important means of adapting to environmental change. However, there is a great deal of strain variation in the expression of Flo11-dependent phenotypes, including flocculation. In this study, we investigated the molecular basis of this strain-specific phenotypic variability. Our data indicate that strain-specific differences in the level of flocculation result from significant sequence differences in the FLO11 alleles and do not depend on quantitative differences in FLO11 expression or on surface hydrophobicity. We further have shown that beads coated with amino-terminal domain peptide bind preferentially to homologous cells. These data show that variability in the structure of the Flo11 adhesion domain may thus be an important determinant of membership in microbial communities and hence may drive selection and evolution.
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25
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Force Sensitivity in Saccharomyces cerevisiae Flocculins. mSphere 2016; 1:mSphere00128-16. [PMID: 27547825 PMCID: PMC4989244 DOI: 10.1128/msphere.00128-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/27/2016] [Indexed: 12/28/2022] Open
Abstract
The Saccharomyces cerevisiae flocculins mediate the formation of cellular aggregates and biofilm-like mats, useful in clearing yeast from fermentations. An important property of fungal adhesion proteins, including flocculins, is the ability to form catch bonds, i.e., bonds that strengthen under tension. This strengthening is based, at least in part, on increased avidity of binding due to clustering of adhesins in cell surface nanodomains. This clustering depends on amyloid-like β-aggregation of short amino acid sequences in the adhesins. In Candida albicans adhesin Als5, shear stress from vortex mixing can unfold part of the protein to expose aggregation-prone sequences, and then adhesins aggregate into nanodomains. We therefore tested whether shear stress from mixing can increase flocculation activity by potentiating similar protein remodeling and aggregation in the flocculins. The results demonstrate the applicability of the Als adhesin model and provide a rational framework for the enhancement or inhibition of flocculation in industrial applications. Many fungal adhesins have short, β-aggregation-prone sequences that play important functional roles, and in the Candida albicans adhesin Als5p, these sequences cluster the adhesins after exposure to shear force. Here, we report that Saccharomyces cerevisiae flocculins Flo11p and Flo1p have similar β-aggregation-prone sequences and are similarly stimulated by shear force, despite being nonhomologous. Shear from vortex mixing induced the formation of small flocs in cells expressing either adhesin. After the addition of Ca2+, yeast cells from vortex-sheared populations showed greatly enhanced flocculation and displayed more pronounced thioflavin-bright surface nanodomains. At high concentrations, amyloidophilic dyes inhibited Flo1p- and Flo11p-mediated agar invasion and the shear-induced increase in flocculation. Consistent with these results, atomic force microscopy of Flo11p showed successive force-distance peaks characteristic of sequentially unfolding tandem repeat domains, like Flo1p and Als5p. Flo11p-expressing cells bound together through homophilic interactions with adhesion forces of up to 700 pN and rupture lengths of up to 600 nm. These results are consistent with the potentiation of yeast flocculation by shear-induced formation of high-avidity domains of clustered adhesins at the cell surface, similar to the activation of Candida albicans adhesin Als5p. Thus, yeast adhesins from three independent gene families use similar force-dependent interactions to drive cell adhesion. IMPORTANCE The Saccharomyces cerevisiae flocculins mediate the formation of cellular aggregates and biofilm-like mats, useful in clearing yeast from fermentations. An important property of fungal adhesion proteins, including flocculins, is the ability to form catch bonds, i.e., bonds that strengthen under tension. This strengthening is based, at least in part, on increased avidity of binding due to clustering of adhesins in cell surface nanodomains. This clustering depends on amyloid-like β-aggregation of short amino acid sequences in the adhesins. In Candida albicans adhesin Als5, shear stress from vortex mixing can unfold part of the protein to expose aggregation-prone sequences, and then adhesins aggregate into nanodomains. We therefore tested whether shear stress from mixing can increase flocculation activity by potentiating similar protein remodeling and aggregation in the flocculins. The results demonstrate the applicability of the Als adhesin model and provide a rational framework for the enhancement or inhibition of flocculation in industrial applications.
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26
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Beaussart A, Abellán-Flos M, El-Kirat-Chatel S, Vincent SP, Dufrêne YF. Force Nanoscopy as a Versatile Platform for Quantifying the Activity of Antiadhesion Compounds Targeting Bacterial Pathogens. NANO LETTERS 2016; 16:1299-1307. [PMID: 26812480 DOI: 10.1021/acs.nanolett.5b04689] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The development of bacterial strains that are resistant to multiple antibiotics has urged the need for new antibacterial therapies. An exciting approach to fight bacterial diseases is the use of antiadhesive agents capable to block the adhesion of the pathogens to host tissues, the first step of infection. We report the use of a novel atomic force microscopy (AFM) platform for quantifying the activity of antiadhesion compounds directly on living bacteria, thus without labeling or purification. Novel fullerene-based mannoconjugates bearing 10 carbohydrate ligands and a thiol bond were efficiently prepared. The thiol functionality could be exploited as a convenient handle to graft the multimeric species onto AFM tips. Using a combination of single-molecule and single-cell AFM assays, we demonstrate that, unlike mannosidic monomers, multivalent glycofullerenes strongly block the adhesion of uropathogenic Escherichia coli bacteria to their carbohydrate receptors. We expect that the nanoscopy technique developed here will help designing new antiadhesion drugs to treat microbial infections, including those caused by multidrug resistant organisms.
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Affiliation(s)
- Audrey Beaussart
- Université catholique de Louvain , Institute of Life Sciences, Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
| | - Marta Abellán-Flos
- University of Namur , Department of Chemistry, Rue de Bruxelles 61, 5000 Namur, Belgium
| | - Sofiane El-Kirat-Chatel
- Université catholique de Louvain , Institute of Life Sciences, Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
| | - Stéphane P Vincent
- University of Namur , Department of Chemistry, Rue de Bruxelles 61, 5000 Namur, Belgium
| | - Yves F Dufrêne
- Université catholique de Louvain , Institute of Life Sciences, Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
- Walloon Excellence in Life sciences and Biotechnology (WELBIO) 1300 Wavre, Belgium
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El-Kirat-Chatel S, Dufrêne YF. Nanoscale adhesion forces between the fungal pathogen Candida albicans and macrophages. NANOSCALE HORIZONS 2016; 1:69-74. [PMID: 32260605 DOI: 10.1039/c5nh00049a] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The development of fungal infections is tightly controlled by the interaction of fungal pathogens with host immune cells. While the recognition of specific fungal cell wall components by immune receptors has been widely investigated, the molecular forces involved are not known. In this Communication, we show the ability of single-cell force spectroscopy to quantify the specific adhesion forces between the fungal pathogen Candida albicans and macrophages. The Candida-macrophage adhesion force is strong, up to ∼3000 pN, and corresponds to multiple cumulative bonds between lectin receptors expressed on the macrophage membrane and mannan carbohydrates on the fungal cell surface. Adhesion force signatures show constant force plateaus, up to >100 μm long, reflecting the extraction of elongated tethers from the macrophage membrane, a phenomenon which may increase the duration of intercellular adhesion. Adhesion strengthens with time, suggesting that the macrophage membrane engulfs the pathogen quickly after initial contact, leading to its internalization. The force nanoscopy method developed here holds great promise for understanding and controlling the early stages of microbe-immune interactions.
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Affiliation(s)
- Sofiane El-Kirat-Chatel
- Institute of Life Sciences, Université catholique de Louvain, Croix du Sud 4-5, bte L7.07.06, 1348 Louvain-la-Neuve, Belgium.
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29
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Beaussart A, El-Kirat-Chatel S, Fontaine T, Latgé JP, Dufrêne YF. Nanoscale biophysical properties of the cell surface galactosaminogalactan from the fungal pathogen Aspergillus fumigatus. NANOSCALE 2015; 7:14996-15004. [PMID: 26308550 DOI: 10.1039/c5nr04399a] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Many fungal pathogens produce cell surface polysaccharides that play essential roles in host-pathogen interactions. In Aspergillus fumigatus, the newly discovered polysaccharide galactosaminogalactan (GAG) mediates adherence to a variety of substrates through molecular mechanisms that are poorly understood. Here we use atomic force microscopy to unravel the localization and adhesion of GAG on living fungal cells. Using single-molecule imaging with tips bearing anti-GAG antibodies, we found that GAG is massively exposed on wild-type (WT) germ tubes, consistent with the notion that this glycopolymer is secreted by the mycelium of A. fumigatus, while it is lacking on WT resting conidia and on germ tubes from a mutant (Δuge3) deficient in GAG. Imaging germ tubes with tips bearing anti-β-glucan antibodies shows that exposure of β-glucan is strongly increased in the Δuge3 mutant, indicating that this polysaccharide is masked by GAG during hyphal growth. Single-cell force measurements show that expression of GAG on germ tubes promotes specific adhesion to pneumocytes and non-specific adhesion to hydrophobic substrates. These results provide a molecular foundation for the multifunctional adhesion properties of GAG, thus suggesting it could be used as a potential target in anti-adhesion therapy and immunotherapy. Our methodology represents a powerful approach for characterizing the nanoscale organization and adhesion of cell wall polysaccharides during fungal morphogenesis, thereby contributing to increase our understanding of their role in biofilm formation and immune responses.
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Affiliation(s)
- Audrey Beaussart
- Université catholique de Louvain, Institute of Life Sciences, Croix du Sud, 4-5, bte L7.07.06, B-1348 Louvain-la-Neuve, Belgium.
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Dufrêne YF. Sticky microbes: forces in microbial cell adhesion. Trends Microbiol 2015; 23:376-82. [DOI: 10.1016/j.tim.2015.01.011] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/22/2015] [Accepted: 01/23/2015] [Indexed: 11/30/2022]
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