Special Issue "Bacterial Adhesion"

Guest Editor
Prof. Dr. Jukka Finne
Department of Biosciences, Division of Biochemistry and Biotechnology, P. O. Box 56 (Viikinkaari 9), FI 00014 University of Helsinki, Finland
Website: http://www.helsinki.fi/biosciences/biochemistry/finne.htm
E-Mail: jukka.finne@helsinki.fi
Phone: +358 9 191 59040

Dear Collegues,

How bacteria attach themselves to surfaces, extracellular components or other cells plays a crucial role in many natural systems. Bacterial adherence has practical importance in applications in fields as varied as medicine or environmental engineering. Bacteria may bind to many types of living organisms including plants and animals, or even other bacteria. The bacteria may use special appendices, fimbriae or pili, for binding and often display specialized proteins, adhesins, to bind to their molecular targets, which are usually carbohydrates or proteins. Multivalent binding to the binding targets may often be used to overcome the dispersive forces of the environment that prevent adhesion. Biofilm formation is also an efficient strategy for bacterial persistence in diverse niches. Specific signaling may be involved in the process of bacterial adhesion.

The molecular background of bacterial adherence to their targets has been intensively studied, and some mechanisms have been elucidated in detail. Knowledge of the molecular mechanisms is of central importance for practical application such as the development of binding receptor analogues that could be used as novel antibacterial agents. This special issue will cover original research papers and reviews on the broad topic of bacterial adhesion.

Prof. Dr. Jukka Finne
Guest Editor

Submission

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• adhesins
• adhesion inhibition
• antibacterial agents
• bacterial adherence
• fimbriae
• glycoconjugates
• multivalency
• pili

Type of Paper: Review
Title: The Bacterial Flagellum as an Adhesin
Authors: Johanna Haiko and Benita Westerlund-Wikström
Affiliations: General Microbiology, Department of Biosciences, University of Helsinki, Finland; E-Mail: benita.westerlund@helsinki.fi
Abstract: The bacterial flagellum is a complex nanomachine assembled of approximately 25 different proteins. The flagellar basal body traverses the cell wall, whereas the curved hook connects the basal body to the whip-like flagellar filament that protrudes 10-15 μm from the bacterial cell. The flagellum has traditionally been regarded as a motility organelle, but more recently it has become evident that flagella have a number of other biological functions. The major subunit, flagellin/FliC, of the flagellum plays a well-documented role in innate immune response and is a dominant antigen in adaptive immunity. Importantly, flagella have also been reported to function as adhesins. Intact, whole flagella have been indicated as significant in bacterial adhesion to and invasion into host cells. In various pathogens, e.g. Clostridium difficile, Escherichia coli and Pseudomonas aeruginosa, flagellin and the flagellar cap proteins have been reported to function as adhesins and recently, FliC of Shigatoxigenic E. coli was shown to be involved in cellular invasion via lipid rafts. Here, we examine the latest and most important findings regarding flagellar adhesive and invasive properties, especially focusing on the flagellum as a potential virulence factor.

Type of Paper: Review
Title: Structural Sampling of Glycan Interaction Profiles Reveals Mucosal Receptors for Fimbrial Adhesins of Enterotoxigenic Escherichia coli
Authors: Emanuela Lonardi ¹, Kristof Moonens ^2,3, Lieven Buts ^2,3, Arjen de Boer ¹, Johan Olsson ⁴, Manfred Weiss ⁵, Yann Guérardel ⁶, Stefan Oscarson ⁴, Manfred Wuhrer ¹, and Julie Bouckaert ^2,3,6,*
Affiliations: ¹ Biomolecular Mass Spectrometry Unit, Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, P.O. Box 9600, 2300, RC Leiden, The Netherlands.
² Structural Biology Brussels, and
³ Department of Molecular and Cellular Interactions, VIB, at the Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
⁴ Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
⁵ Helmholtz-Zentrum Berlin für Materialien und Energie, Institute for Soft Matter and Functional Materials, Macromolecular Crystallography, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
⁶ Unité de Glycobiologie Structurale et Fonctionnelle, Université Lille 1, UMR CNRS 8576, 59655 Villeneuve d’Ascq, France ; E-Mail: julie.bouckaert@univ-lille1.fr
Abstract: Escherichia coli is a normal commensal of the intestinal flora of most mammal species, however can cause extra-intestinal diseases in the human bladder and can be a dominant infecting agent in the inflamed bowel. Different types of long, proteinaceous adhesion organelles can be expressed on the bacterial envelope, which is determined by the niche colonized and by the E. coli strain. Over the years, we have expressed, purified and structurally determined adhesins from different fimbrial types from enterotoxigenic E. coli (ETEC). For the characterization of their function, we screened F17G, FedF and FimH adhesins and also whole bacterial cells on natural glycan arrays that have been prepared directly from epithelial cells targeted by ETEC. The binding patterns are compared with the binding of the adhesins to glycan arrays of the core H of the Consortium for Functional Glycomics. Integration of these results together with interaction studies using the purified adhesins and with complexes of those fimbrial adhesins with glycan receptors in crystal structures gives new insights into the origin and the driving forces of bacterial fimbrial adhesion.

Type of Paper: Article
Title: Use of Tetravalent Galabiose for Inhibition of Streptococcus Suis Serotype 2 Infection in a Mouse Model
Authors: Roland J. Pieters ^1,*, Hans-Christian Slotved ², Hanne M. L. Arler ², Jukka Finne ³, Sauli Haataja ⁴, John A. F. Joosten ¹, Hilbert M. Branderhorst ¹ and Karen A. Krogfelt ^2,5
Affiliations: ¹ Department of Medicinal Chemistry and Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands; E-Mail: R.J.Pieters@uu.nl; Tel.: 17 +31620293387; Fax +31302536655
² Unit of Gastrointestinal Infections, department of Bacteriology, Mycology and Parasitology (ABMP), Statens Serum Institut, Copenhagen, Denmark
³ Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, P.O.B. 56, Helsinki FI-00014, Finland
⁴ Department of Medical Biochemistry and Genetics, University of Turku, Kiinamyllynkatu 10,Turku FI-20520, Finland
Abstract: Streptococcus suis is an important swine pathogen associated with a variety of infections such as meningitis, arthritis and septicaemia. The bacterium is zoonotic and has been found to cause meningitis especially in humans occupationally exposed to infected pigs. Since adhesion is a prerequisite for colonization and subsequent infection, anti adhesion treatment seems a natural alternative to traditional treatment with antibiotics. Anti-adhesion treatment with a sugar compound has been proposed as an alternative to the traditional treatment, and the synthetic compound tetravalent galabiose has shown promising anti-adhesion effects on S. suis in vitro. The aim of this study was to develop a peritonitis mouse model, which could be used to study S. suis type 2 infection in vivo and to evaluate the effects of tetravalent galabiose on the infection compared to the effect of treatment with penicillin. A peritonitis mouse model was developed in CFW1 mice and S. suis type 2 bacteria were isolated post mortem from liver, lungs, spleen and in a few cases the brain. The model was used to evaluate treatment of S. suis with the synthetic tetravalent galabiose compound which showed promising results.

Type of Paper: Review
Title: The Biology of Neisseria Ddhesins
Authors: Miao-Chiu Hung and Myron Christodoulides
Affiliations: Neisseria Research Group, Molecular Microbiology, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, University of Southampton Faculty of Medicine, Southampton General Hospital, Southampton, SO16 6YD, UK; E-Mails: mc4@soton.ac.uk; Mh1y11@soton.ac.uk
Abstract: Members of the genus Neisseria include pathogens causing important human diseases such as meningitis, septicaemia, gonorrhoea and pelvic inflammatory disease syndrome. Neisseriae are found on the exposed epithelia of the upper respiratory tract and the urogenital tract. Colonisation of these exposed epithelia is dependent on a repertoire of diverse bacterial molecules, extending not only from the surface of the bacteria but also found within the outer membrane. During invasive disease, pathogenic Neisseriae also interact with immune effector cells, vascular endothelia and the meninges. Neisseria adhesion involves the interplay of these multiple surface factors and in this review we discuss the structure and function of these important molecules, the nature of the host cell receptors involved in their recognition and the biological consequences of these interactions. We also describe the current status for recently-identified Neisseria adhesins. Understanding the biology of Neisseria adhesins has an impact not only on the development of new vaccines but also in revealing a great deal about human biology.

Title: Adherence of Helicobacter Pylori
Authors: Mónica Oleastro ¹ and Armelle Ménard ²
Affiliations: ¹ Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal; E-Mail: Monica.Oleastro@insa.min-saude.pt
² INSERM U853, Bordeaux, France, Université Bordeaux 2 Bordeaux Segalen, Laboratoire de Bactériologie, Bordeaux, France
Abstract: Helicobacter pylori is one of the most successful human pathogens, which colonizes the mucus layer of the gastric epithelium of more than 50% of the world's population. This curved microaerophilic gram negative bacterium induces a chronic active gastritis, often asymptomatic, in all infected individuals. In some cases, this gastritis evolves to more severe diseases such as peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Helicobacter pylori has developed a unique set of factors, actively supporting its successful survival and persistence in its natural hostile ecological niche, the human stomach, throughout the individual’s life, unless treated.
In the human stomach, the vast majority of H. pylori cells are found motile in the mucus layer lining, but a small part is found adherent to the epithelial cells surfaces. Adherence to the gastric epithelium is important for the ability of H. pylori to cause disease because this intimate attachment facilitates: 1) colonization and persistence, by preventing the bacteria from being eliminated from the stomach, by mucus turnover and gastric peristalsis; 2) evasion from the human immune system and 3) efficient delivery of proteins into the gastric cell, such as the CagA oncoprotein and the VacA cytotoxin. Therefore, bacteria with better adherence properties colonize the host at higher densities. Helicobacter pylori is one of the most genetically diverse bacterial species known and is equipped with an extraordinarily large set of outer membrane proteins, whose role in the infection and persistence process will be discussed in this chapter, as well as the different receptor structures that have been so far described for mucosal adherence.

Type of Paper: Review
Title: Bacterial Adhesion of Streptococcus Suis to Host Cells and its Inhibition by Carbohydrate Ligands
Authors: Annika Kouki 1, Roland J. Pieters 2, Ulf J. Nilsson 3, Vuokko Loimaranta 1, Jukka Finne 4 and Sauli Haataja 1,*
Affiliations: 1. Department of Medical Biochemistry and Genetics, University of Turku, Kiinamyllynkatu 10, FI-20520 Turku, Finland; E-Mails; annika.kouki@utu.fi (A.K.); vuokko.loimaranta@utu.fi (V.L.); sauli.haataja@utu.fi (S.H.)
2. Department of Medicinal Chemistry and Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands; E-Mail: r.j.pieters@uu.nl (R.J.P.)
3. Centre for Analysis and Synthesis, Department of Chemistry, Lund University, POB 124, SE-22100, Lund, Sweden; E-Mail: ulf.nilsson@organic.lu.se (U.J.N)
4. Department of Biosciences, Division of Biochemistry and Biotechnology, University of Helsinki, P.O.B. 56, FI-00014 Helsinki, Finland; E-Mail: jukka.finne@helsinki.fi
Abstract: Streptococcus suis is a gram-positive bacterium which causes sepsis and meningitis in pigs and humans. This review summarizes known S. suis virulence factors and carbohydrate-based adhesion mechanisms, as well as the inhibition of adhesion by anti-adhesion compounds. Virulence factors of S. suis include antiphagocytic polysaccharide capsules and individual protein molecules such as suilysin. Recent genomic studies have identified new cell wall proteins many of which are required for bacterial survival or are immunogenic in the host. Nevertheless their function and biological role remains elusive. Carbohydrate-binding specificities of S. suis have been identified, and these studies have shown that many strains recognize Galα1–4Gal- containing oligosaccharides present in host blood group P glycolipids. In the era of increasing antibiotic resistance new means to treat infections are needed. Since microbial adhesion to carbohydrates is important to establish disease, compounds blocking adhesion could be an alternative to antibiotics. The use of oligosaccharides as drugs is generally hampered by their relatively low affinity (micromolar) to compete with multivalent binding to host receptors. However, screening of libraries of chemically modified Galα1–4Gal derivatives has identified compounds that inhibit S. suis adhesion in nanomolar range. On the other hand design of multivalent Galα1–4Gal-containing dendrimers has resulted in a significant increase of the inhibitory potency of the disaccharide. The adhesin binding to Galα1–4Gal-oligosaccharides was recently identified to be streptococcal adhesin P (SadP). It has a Galα1–4Gal-binding N-terminal domain and a C-terminal domain containing an LPNTG-motif covalently attaching it to cell wall. The carbohydrate-binding domain has no homology to E. coli P fimbrial adhesin, which suggest that these gram-positive and negative bacterial adhesins recognizing the same receptor have evolved by convergent evolution. SadP adhesin may represent a promising target for the design of anti-adhesion ligands for the prevention and treatment of S. suis infections.

Type of Paper: Review
Title: The Effect of Salinity on the Adhesion of a Cyanobacterium, Synechocystis, as Determined by Fluid Dynamic Gauging
Authors: P. Bombelli ¹, Q. Yang ², A. Ali ², A.J. McCormick ¹, C.J. Howe ¹ and D.I. Wilson ²
Affiliations: ¹ Department of Biochemistry, University of Cambridge
² Department of Chemical Engineering and Biotechnology, University of Cambridge; E-Mail: diw11@cam.ac.uk
Abstract: Fluid dynamic gauging is a novel, non-contact measurement technique for measuring the thickness and strength of soft-solid layers and coatings immersed in their native liquid in situ and in real time. Salley et al. (2012) demonstrated its application to measure the thickness and adhesion strength of biofilms formed by a marine cyanobacterium (Synechococcus sp. WH 5701) on different substrates. A new mode of dynamic gauging measurements is reported here, wherein the volume of gauging fluid is conserved, rendering the technique suitable for aseptic studies. The technique was used to study the fresh water cyanobacterium Synechocystis sp. PCC 6803, a euryhaline species that has been shown previously to not readily adhere to substrate surfaces (McCormick et al., 2011). Here we report for the first time that Synechocystis can be induced to grow measureable biofilms on an indium tin oxide-coated polyethylene terephthalate (ITO-PET) substrate by increasing the salinity of the medium. The metabolic adjustments that might be responsible for promoting cell/substrate adhesion in response to increased salinity are discussed.

Type of Paper: Review
Title: Adhesion of Diarrheagenic Escherichia coli and Inhibition by Glycocompounds Engaged in the Mucosal Innate Immunity
Authors: Alex L. Pereira ^1,2,* and Loreny G. Giugliano ²
Affiliation: ¹ College of Ceilândia, University of Brasília, Brasília-DF, 72220-900, Brazil
² Laboratory of Microbiology, Department of Cellular Biology, University of Brasília, Brasília-DF, 70910-900, Brazil; E-Mail: giuglian@unb.br; alexpereira@unb.br
Abstract: Escherichia coli colonizes the human intestine in a short time following the birth with most of the strains engaging in a commensal relationship. However, some E. coli strains have evolved toward to acquire genetic traits associated with virulence. Nowadays, five categories of enteroadherent E. coli strains are well-recognized and are classified with regards to the expressed adhesins and the strategy adopted during the colonization. The high morbidity associated to diarrhea has incited researches focusing on E. coli adhesins, as well on factors that inhibit bacterial adherence. The breastfeeding has been proved to be the most effective strategy for preventing diarrhea in children. Putting aside the immunoglobulin content, glycocompounds and oligosaccharides in the human milk play a critical role in the innate immunity against diarrheagenic E. coli strains. This review brings a summary of the colonization factors and virulence strategies explored by diarrheagenic E. coli strains, addressing the inhibitory effects that oligosaccharides and glycocompounds, such as lactoferrin and free secretory component, exert on the adherence and virulence of these
strains. In conclusion, a collection of experimental data have proved that human milk glycocompounds may respond for the universal protective effect imputed to the breastfeeding against diarrheagenic E. coli pathotypes.