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Synchronized Swarmers and Sticky Stalks: Caulobacter crescentus as a Model for Bacterial Cell Biology. J Bacteriol 2023; 205:e0038422. [PMID: 36715542 PMCID: PMC9945503 DOI: 10.1128/jb.00384-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
First isolated and classified in the 1960s, Caulobacter crescentus has been instrumental in the study of bacterial cell biology and differentiation. C. crescentus is a Gram-negative alphaproteobacterium that exhibits a dimorphic life cycle composed of two distinct cell types: a motile swarmer cell and a nonmotile, division-competent stalked cell. Progression through the cell cycle is accentuated by tightly controlled biogenesis of appendages, morphological transitions, and distinct localization of developmental regulators. These features as well as the ability to synchronize populations of cells and follow their progression make C. crescentus an ideal model for answering questions relevant to how development and differentiation are achieved at the single-cell level. This review will explore the discovery and development of C. crescentus as a model organism before diving into several key features and discoveries that have made it such a powerful organism to study. Finally, we will summarize a few of the ongoing areas of research that are leveraging knowledge gained over the last century with C. crescentus to highlight its continuing role at the forefront of cell and developmental biology.
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Liu Q, Hao LF, Chen Y, Liu ZC, Xing WW, Zhang C, Fu WL, Xu DG. The Screening and Expression of Polysaccharide Deacetylase from Caulobacter crescentus and Its Function Analysis. Biotechnol Appl Biochem 2022; 70:688-696. [PMID: 35932185 DOI: 10.1002/bab.2390] [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: 08/23/2021] [Accepted: 07/12/2022] [Indexed: 11/06/2022]
Abstract
The bacterium Caulobacter crescentus secretes an adhesive polysaccharide called holdfast which is the known strongest underwater adhesive in nature. The deacetylase encoded by hfs (holdfast synthesis) H gene is a key factor affecting the adhesion of holdfast. Its structure and function are not yet clear, and whether other polysaccharide deacetylases exist in C. crescentus is still unknown. The screening of both HfsH and its structural analogue as well as their purification from the artificial expression products of E. coli. is the first step to clarify these questions. Here, we determined the conserved domains of HfsH via sequence alignment among Carbohydrate Esterase family 4 enzymes and screened out its structural analogue (CC_2574) in C. crescentus. The recombinant HfsH and CC_2574 were effectively expressed in E. coli. Both of them were purified by chromatography from their corresponding productions in E. coli., and were then functionally analyzed. The results indicated that a high deacetylase activity (61.8 U/mg) was observed in recombinant HfsH but not in CC_2574, which suggesting that HfsH might be the irreplaceable gene mediating adhesion of holdfast in C. crescentus. Moreover, the divalent metal ions Zn2+ , Mg2+ , Mn2+ could promote the activity of recombinant HfsH at the concentration from 0.05mM to 1mM, but inhibit its activity when the concentration exceeds 1mM. In sum, our study firstly realized the artificial production of polysaccharide deacetylase HfsH and its structural analogue, and further explored their functions, both of which laid the foundation for the development of new adhesive materials. Expression of polysaccharide deacetylase HfsH promoting the adhesion of holdfast The effects of various metal ions on the deacetylase activity of recombinant HfsH Functional analysis of recombinant polysaccharide deacetylase Screening of functional analogue of HfsH in Caulobacter crescentus based on ts conserved domains This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Qing Liu
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Li-Fang Hao
- College of Pharmaceutical Sciences, Hebei University, Baoding, Hebei, 071002, China
| | - Yao Chen
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Zhong-Cheng Liu
- College of Pharmaceutical Sciences, Hebei University, Baoding, Hebei, 071002, China
| | - Wei-Wei Xing
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Chao Zhang
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Wen-Liang Fu
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Dong-Gang Xu
- Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
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Xu L, Tang S, Yang H, Liang M, Ren P, Wei D, He J, Kong W, Liu P, Zhang T. Sustained delivery of gemcitabine via in situ injectable mussel-inspired hydrogel for local therapy of pancreatic cancer. J Mater Chem B 2022; 10:6338-6350. [DOI: 10.1039/d1tb02858h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The issue on pervasively enhanced drug resistance of pancreatic cancer is fundamental to better understanding of gemcitabine-based chemotherapy. Currently available treatment plans containing injectable therapeutics are mainly engineered to improve...
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Narayanan A, Dhinojwala A, Joy A. Design principles for creating synthetic underwater adhesives. Chem Soc Rev 2021; 50:13321-13345. [PMID: 34751690 DOI: 10.1039/d1cs00316j] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Water and adhesives have a conflicting relationship as demonstrated by the failure of most man-made adhesives in underwater environments. However, living creatures routinely adhere to substrates underwater. For example, sandcastle worms create protective reefs underwater by secreting a cocktail of protein glue that binds mineral particles together, and mussels attach themselves to rocks near tide-swept sea shores using byssal threads formed from their extracellular secretions. Over the past few decades, the physicochemical examination of biological underwater adhesives has begun to decipher the mysteries behind underwater adhesion. These naturally occurring adhesives have inspired the creation of several synthetic materials that can stick underwater - a task that was once thought to be "impossible". This review provides a comprehensive overview of the progress in the science of underwater adhesion over the past few decades. In this review, we introduce the basic thermodynamics processes and kinetic parameters involved in adhesion. Second, we describe the challenges brought by water when adhering underwater. Third, we explore the adhesive mechanisms showcased by mussels and sandcastle worms to overcome the challenges brought by water. We then present a detailed review of synthetic underwater adhesives that have been reported to date. Finally, we discuss some potential applications of underwater adhesives and the current challenges in the field by using a tandem analysis of the reported chemical structures and their adhesive strength. This review is aimed to inspire and facilitate the design of novel synthetic underwater adhesives, that will, in turn expand our understanding of the physical and chemical parameters that influence underwater adhesion.
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Affiliation(s)
- Amal Narayanan
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA.
| | - Ali Dhinojwala
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA.
| | - Abraham Joy
- School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH 44325, USA.
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Nyarko A, Singla S, Barton HA, Dhinojwala A. Spectroscopic Identification of Peptide Chemistry in the Caulobacter crescentus Holdfast. Biochemistry 2020; 59:3508-3516. [PMID: 32844640 DOI: 10.1021/acs.biochem.0c00625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bacterium Caulobacter crescentus is known to attach irreversibly to underwater surfaces by utilizing an adhesive structure called the holdfast, which exhibits the greatest known adhesive strength of any organism. The very small size of the holdfast (∼400 nm wide and ∼40 nm high) has made direct chemical analysis difficult, and its structure remains poorly understood. In this study, we employ spectroscopic techniques, including attenuated total reflection infrared spectroscopy (ATR-IR) and X-ray photoelectron spectroscopy, to probe holdfast chemistry. The data indicate the presence of a peptide signal within the holdfast polymer. By comparing the ATR-IR spectrum of the holdfast to peptidoglycan spectra from other bacterial species, we demonstrate the similarity of the holdfast chemistry to that of peptidoglycan, suggesting peptide cross-linking may play a role in holdfast architecture. To probe the molecular groups at the interface, surface-sensitive sum frequency generation spectroscopy was used to show that aromatic and hydroxyl groups related to this protein content at the adhesive interface could be playing a crucial role in adhesion. On the basis of these results, we propose a model of the holdfast architecture with similarities to the peptide cross-linking observed in the peptidoglycan polymer of the bacterial cell wall. These results not only provide information about the development of adhesives that could be based on holdfast chemical architecture but also reveal a potentially yet unexplored biosynthetic pathway in holdfast synthesis that has not yet been revealed by genetic approaches, thereby opening up a potentially new avenue of research in holdfast synthesis.
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Affiliation(s)
- Alex Nyarko
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Saranshu Singla
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
| | - Hazel A Barton
- Department of Biology, The University of Akron, Akron, Ohio 44325, United States
| | - Ali Dhinojwala
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States
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Cedano-Serrano FJ, Sidoli U, Synytska A, Tran Y, Hourdet D, Creton C. From Molecular Electrostatic Interactions and Hydrogel Architecture to Macroscopic Underwater Adherence. Macromolecules 2019. [DOI: 10.1021/acs.macromol.8b02696] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Francisco J. Cedano-Serrano
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL University, Sorbonne University, CNRS, F-75005 Paris, France
| | - Ugo Sidoli
- Department of Polymer Interfaces, Leibniz Institute of Polymer Research, Hohe Strasse 6, D-01069 Dresden, Germany
- Technische Universität Dresden, D-01062 Dresden, Germany
| | - Alla Synytska
- Department of Polymer Interfaces, Leibniz Institute of Polymer Research, Hohe Strasse 6, D-01069 Dresden, Germany
- Technische Universität Dresden, D-01062 Dresden, Germany
| | - Yvette Tran
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL University, Sorbonne University, CNRS, F-75005 Paris, France
| | - Dominique Hourdet
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL University, Sorbonne University, CNRS, F-75005 Paris, France
| | - Costantino Creton
- Soft Matter Sciences and Engineering, ESPCI Paris, PSL University, Sorbonne University, CNRS, F-75005 Paris, France
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Procter P, Pujari-Palmer M, Hulsart-Billström G, Wenner D, Insley G, Larsson S, Engqvist H. A biomechanical test model for evaluating osseous and osteochondral tissue adhesives. BMC Biomed Eng 2019; 1:11. [PMID: 32903290 PMCID: PMC7422571 DOI: 10.1186/s42490-019-0011-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/31/2019] [Indexed: 01/01/2023] Open
Abstract
Background Currently there are no standard models with which to evaluate the biomechanical performance of calcified tissue adhesives, in vivo. We present, herein, a pre-clinical murine distal femoral bone model for evaluating tissue adhesives intended for use in both osseous and osteochondral tissue reconstruction. Results Cylindrical cores (diameter (Ø) 2 mm (mm) × 2 mm depth), containing both cancellous and cortical bone, were fractured out from the distal femur and then reattached using one of two tissue adhesives. The adhesiveness of fibrin glue (Tisseeltm), and a novel, biocompatible, calcium phosphate-based tissue adhesive (OsStictm) were evaluated by pullout testing, in which glued cores were extracted and the peak force at failure recorded. The results show that Tisseel weakly bonded the metaphyseal bone cores, while OsStic produced > 30-fold higher mean peak forces at failure (7.64 Newtons (N) vs. 0.21 N). The failure modes were consistently disparate, with Tisseel failing gradually, while OsStic failed abruptly, as would be expected with a calcium-based material. Imaging of the bone/adhesive interface with microcomputed tomography revealed that, for OsStic, failure occurred more often within cancellous bone (75% of tested samples) rather than at the adhesive interface. Conclusions Despite the challenges associated with biomechanical testing in small rodent models the preclinical ex-vivo test model presented herein is both sensitive and accurate. It enabled differences in tissue adhesive strength to be quantified even for very small osseous fragments (<Ø4mm). Importantly, this model can easily be scaled to larger animals and adapted to fracture fragment fixation in human bone. The present model is also compatible with other long-term in vivo evaluation methods (i.e. in vivo imaging, histological analysis, etc.).
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Affiliation(s)
- Philip Procter
- Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 523, 75120 Uppsala, Sweden.,GPBio Ltd, Rathkeale, Ireland
| | - Michael Pujari-Palmer
- Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Gry Hulsart-Billström
- Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 523, 75120 Uppsala, Sweden.,Department Surgical Sciences, Orthopaedics, Uppsala University Hospital, 75185 Uppsala, Sweden
| | - David Wenner
- Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 523, 75120 Uppsala, Sweden
| | - Gerard Insley
- Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 523, 75120 Uppsala, Sweden.,GPBio Ltd, Rathkeale, Ireland
| | - Sune Larsson
- Department Surgical Sciences, Orthopaedics, Uppsala University Hospital, 75185 Uppsala, Sweden
| | - Håkan Engqvist
- Division of Applied Materials Science, Department of Engineering Sciences, Uppsala University, Box 523, 75120 Uppsala, Sweden
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Pujari-Palmer M, Guo H, Wenner D, Autefage H, Spicer CD, Stevens MM, Omar O, Thomsen P, Edén M, Insley G, Procter P, Engqvist H. A Novel Class of Injectable Bioceramics that Glue Tissues and Biomaterials. MATERIALS 2018; 11:ma11122492. [PMID: 30544596 PMCID: PMC6316977 DOI: 10.3390/ma11122492] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 01/21/2023]
Abstract
Calcium phosphate cements (CPCs) are clinically effective void fillers that are capable of bridging calcified tissue defects and facilitating regeneration. However, CPCs are completely synthetic/inorganic, unlike the calcium phosphate that is found in calcified tissues, and they lack an architectural organization, controlled assembly mechanisms, and have moderate biomechanical strength, which limits their clinical effectiveness. Herein, we describe a new class of bioinspired CPCs that can glue tissues together and bond tissues to metallic and polymeric biomaterials. Surprisingly, alpha tricalcium phosphate cements that are modified with simple phosphorylated amino acid monomers of phosphoserine (PM-CPCs) bond tissues up to 40-fold stronger (2.5–4 MPa) than commercial cyanoacrylates (0.1 MPa), and 100-fold stronger than surgical fibrin glue (0.04 MPa), when cured in wet-field conditions. In addition to adhesion, phosphoserine creates other novel properties in bioceramics, including a nanoscale organic/inorganic composite microstructure, and templating of nanoscale amorphous calcium phosphate nucleation. PM-CPCs are made of the biocompatible precursors calcium, phosphate, and amino acid, and these represent the first amorphous nano-ceramic composites that are stable in liquids.
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Affiliation(s)
- Michael Pujari-Palmer
- Applied material science, Department of Engineering, Uppsala University, Uppsala 75121, Sweden.
| | - Hua Guo
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 106 91, Sweden.
| | - David Wenner
- Applied material science, Department of Engineering, Uppsala University, Uppsala 75121, Sweden.
| | - Hélène Autefage
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm 17177, Sweden.
| | - Christopher D Spicer
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm 17177, Sweden.
| | - Molly M Stevens
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm 17177, Sweden.
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK.
| | - Omar Omar
- Department of Biomaterials, Institute of Clinical Sciences, University of Gothenburg, Gothenburg 40530, Sweden.
| | - Peter Thomsen
- Department of Biomaterials, Institute of Clinical Sciences, University of Gothenburg, Gothenburg 40530, Sweden.
| | - Mattias Edén
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm 106 91, Sweden.
| | - Gerard Insley
- Applied material science, Department of Engineering, Uppsala University, Uppsala 75121, Sweden.
| | - Philip Procter
- Applied material science, Department of Engineering, Uppsala University, Uppsala 75121, Sweden.
| | - Hakan Engqvist
- Applied material science, Department of Engineering, Uppsala University, Uppsala 75121, Sweden.
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Li X, Li W, Liu Z, Wang X, Guo H, Wang R, Guo X, Li C, Jia X. Underwater polyurethane adhesive with enhanced cohesion by postcrosslinking of glycerol monomethacrylate. J Appl Polym Sci 2018. [DOI: 10.1002/app.46579] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Xie Li
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
| | - Wei Li
- Chemistry Department; Technische Universität Dresden; Mommsenstrasse 4 Dresden 01062 Germany
| | - Zhiqing Liu
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
| | - Xiaolin Wang
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
| | - Heling Guo
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
| | - Rongjie Wang
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
| | - Xuhong Guo
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
- State Key Laboratory of Chemical Engineering; East China University of Science and Technology; Shanghai 200237 People's Republic of China
| | - Cuihua Li
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
| | - Xin Jia
- School of Chemistry and Chemical Engineering/Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan, Key Laboratory of Materials-Oriented Chemical Engineering of the Xinjiang Uygur Autonomous Region, Engineering Research Center of Materials-Oriented Chemical Engineering of Xinjiang Bingtuan; Shihezi University; Shihezi 832003 People's Republic of China
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Layered Structure and Complex Mechanochemistry Underlie Strength and Versatility in a Bacterial Adhesive. mBio 2018; 9:mBio.02359-17. [PMID: 29437925 PMCID: PMC5801468 DOI: 10.1128/mbio.02359-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
While designing synthetic adhesives that perform in aqueous environments has proven challenging, microorganisms commonly produce bioadhesives that efficiently attach to a variety of substrates, including wet surfaces. The aquatic bacterium Caulobacter crescentus uses a discrete polysaccharide complex, the holdfast, to strongly attach to surfaces and resist flow. The holdfast is extremely versatile and has impressive adhesive strength. Here, we used atomic force microscopy in conjunction with superresolution microscopy and enzymatic assays to unravel the complex structure of the holdfast and to characterize its chemical constituents and their role in adhesion. Our data support a model whereby the holdfast is a heterogeneous material organized as two layers: a stiffer nanoscopic core layer wrapped into a sparse, far-reaching, flexible brush layer. Moreover, we found that the elastic response of the holdfast evolves after surface contact from initially heterogeneous to more homogeneous. From a composition point of view, besides N-acetyl-d-glucosamine (NAG), the only component that had been identified to date, our data show that the holdfast contains peptides and DNA. We hypothesize that, while polypeptides are the most important components for adhesive force, the presence of DNA mainly impacts the brush layer and the strength of initial adhesion, with NAG playing a primarily structural role within the core. The unanticipated complexity of both the structure and composition of the holdfast likely underlies its versatility as a wet adhesive and its distinctive strength. Continued improvements in understanding of the mechanochemistry of this bioadhesive could provide new insights into how bacteria attach to surfaces and could inform the development of new adhesives.IMPORTANCE There is an urgent need for strong, biocompatible bioadhesives that perform underwater. To strongly adhere to surfaces and resist flow underwater, the bacterium Caulobacter crescentus produces an adhesive called the holdfast, the mechanochemistry of which remains undefined. We show that the holdfast is a layered structure with a stiff core layer and a polymeric brush layer and consists of polysaccharides, polypeptides, and DNA. The DNA appears to play a role in the structure of the brush layer and initial adhesion, the peptides in adhesive strength, and the polysaccharides in the structure of the core. The complex, multilayer organization and diverse chemistry described here underlie the distinctive adhesive properties of the holdfast and will provide important insights into the mechanisms of bacterial adhesion and bioadhesive applications.
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