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Liu W, Shi R, Zhang Y, Li C, Zhou X, Jensen MS, Yang J, Zhao S, Liu J, Zhu J, Liu C, Sun D. ROK family regulator NagC promotes prodigiosin biosynthesis independent of N-acetylglucosamine in Serratia sp. ATCC 39006. Appl Environ Microbiol 2024:e0089124. [PMID: 38953369 DOI: 10.1128/aem.00891-24] [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: 05/10/2024] [Accepted: 06/11/2024] [Indexed: 07/04/2024] Open
Abstract
Serratia sp. ATCC 39006 is an important model strain for the study of prodigiosin production, whose prodigiosin biosynthesis genes (pigA-O) are arranged in an operon. Several transcription factors have been shown to control the transcription of the pig operon. However, since the regulation of prodigiosin biosynthesis is complex, the regulatory mechanism for this process has not been well established. In most γ-proteobacteria, the ROK family regulator NagC acts as a global transcription factor in response to N-acetylglucosamine (GlcNAc). In Serratia sp. ATCC 39006, NagC represses the transcription of two divergent operons, nagE and nagBAC, which encode proteins involved in the transport and metabolism of GlcNAc. Moreover, NagC directly binds to a 21-nt region that partially overlaps the -10 and -35 regions of the pig promoter and promotes the transcription of prodigiosin biosynthesis genes, thereby increasing prodigiosin production. Although NagC still acts as both repressor and activator in Serratia sp. ATCC 39006, its transcriptional regulatory activity is independent of GlcNAc. NagC was first found to regulate antibiotic biosynthesis in Gram-negative bacteria, and NagC-mediated regulation is not responsive to GlcNAc, which contributes to future studies on the regulation of secondary metabolism by NagC in other bacteria. IMPORTANCE The ROK family transcription factor NagC is an important global regulator in the γ-proteobacteria. A large number of genes involved in the transport and metabolism of sugars, as well as those associated with biofilm formation and pathogenicity, are regulated by NagC. In all of these regulations, the transcriptional regulatory activity of NagC responds to the supply of GlcNAc in the environment. Here, we found for the first time that NagC can regulate antibiotic biosynthesis, whose transcriptional regulatory activity is independent of GlcNAc. This suggests that NagC may respond to more signals and regulate more physiological processes in Gram-negative bacteria.
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Affiliation(s)
- Weijie Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Rui Shi
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Ying Zhang
- School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Chenchen Li
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Xuge Zhou
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Marcus Sepo Jensen
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jing Yang
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Siyi Zhao
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jiawen Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Jingrong Zhu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Cong Liu
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
| | - Di Sun
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu, China
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Escobar-Salom M, Barceló IM, Jordana-Lluch E, Torrens G, Oliver A, Juan C. Bacterial virulence regulation through soluble peptidoglycan fragments sensing and response: knowledge gaps and therapeutic potential. FEMS Microbiol Rev 2023; 47:fuad010. [PMID: 36893807 PMCID: PMC10039701 DOI: 10.1093/femsre/fuad010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 02/10/2023] [Accepted: 03/07/2023] [Indexed: 03/11/2023] Open
Abstract
Given the growing clinical-epidemiological threat posed by the phenomenon of antibiotic resistance, new therapeutic options are urgently needed, especially against top nosocomial pathogens such as those within the ESKAPE group. In this scenario, research is pushed to explore therapeutic alternatives and, among these, those oriented toward reducing bacterial pathogenic power could pose encouraging options. However, the first step in developing these antivirulence weapons is to find weak points in the bacterial biology to be attacked with the goal of dampening pathogenesis. In this regard, during the last decades some studies have directly/indirectly suggested that certain soluble peptidoglycan-derived fragments display virulence-regulatory capacities, likely through similar mechanisms to those followed to regulate the production of several β-lactamases: binding to specific transcriptional regulators and/or sensing/activation of two-component systems. These data suggest the existence of intra- and also intercellular peptidoglycan-derived signaling capable of impacting bacterial behavior, and hence likely exploitable from the therapeutic perspective. Using the well-known phenomenon of peptidoglycan metabolism-linked β-lactamase regulation as a starting point, we gather and integrate the studies connecting soluble peptidoglycan sensing with fitness/virulence regulation in Gram-negatives, dissecting the gaps in current knowledge that need filling to enable potential therapeutic strategy development, a topic which is also finally discussed.
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Affiliation(s)
- María Escobar-Salom
- Research Unit and Microbiology Department, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Crtra. Valldemossa 79, 07010 Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC). Av. Monforte de Lemos 3-5, 28029, Madrid, Spain
| | - Isabel María Barceló
- Research Unit and Microbiology Department, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Crtra. Valldemossa 79, 07010 Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC). Av. Monforte de Lemos 3-5, 28029, Madrid, Spain
| | - Elena Jordana-Lluch
- Research Unit and Microbiology Department, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Crtra. Valldemossa 79, 07010 Palma, Spain
| | - Gabriel Torrens
- Research Unit and Microbiology Department, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Crtra. Valldemossa 79, 07010 Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC). Av. Monforte de Lemos 3-5, 28029, Madrid, Spain
- Department of Molecular Biology and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University. Försörjningsvägen 2A, SE-901 87 Umeå, Sweden
| | - Antonio Oliver
- Research Unit and Microbiology Department, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Crtra. Valldemossa 79, 07010 Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC). Av. Monforte de Lemos 3-5, 28029, Madrid, Spain
| | - Carlos Juan
- Research Unit and Microbiology Department, University Hospital Son Espases-Health Research Institute of the Balearic Islands (IdISBa), Crtra. Valldemossa 79, 07010 Palma, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Infecciosas (CIBERINFEC). Av. Monforte de Lemos 3-5, 28029, Madrid, Spain
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Garimano N, Scalise ML, Gómez F, Amaral MM, Ibarra C. Intestinal mucus-derived metabolites modulate virulence of a clade 8 enterohemorrhagic Escherichia coli O157:H7. Front Cell Infect Microbiol 2022; 12:975173. [PMID: 36004327 PMCID: PMC9393340 DOI: 10.3389/fcimb.2022.975173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 07/20/2022] [Indexed: 11/24/2022] Open
Abstract
The human colonic mucus is mainly composed of mucins, which are highly glycosylated proteins. The normal commensal colonic microbiota has mucolytic activity and is capable of releasing the monosaccharides contained in mucins, which can then be used as carbon sources by pathogens such as Enterohemorrhagic Escherichia coli (EHEC). EHEC can regulate the expression of some of its virulence factors through environmental sensing of mucus-derived sugars, but its implications regarding its main virulence factor, Shiga toxin type 2 (Stx2), among others, remain unknown. In the present work, we have studied the effects of five of the most abundant mucolytic activity-derived sugars, Fucose (L-Fucose), Galactose (D-Galactose), N-Gal (N-acetyl-galactosamine), NANA (N-Acetyl-Neuraminic Acid) and NAG (N-Acetyl-D-Glucosamine) on EHEC growth, adhesion to epithelial colonic cells (HCT-8), and Stx2 production and translocation across a polarized HCT-8 monolayer. We found that bacterial growth was maximum when using NAG and NANA compared to Galactose, Fucose or N-Gal, and that EHEC adhesion was inhibited regardless of the metabolite used. On the other hand, Stx2 production was enhanced when using NAG and inhibited with the rest of the metabolites, whilst Stx2 translocation was only enhanced when using NANA, and this increase occurred only through the transcellular route. Overall, this study provides insights on the influence of the commensal microbiota on the pathogenicity of E. coli O157:H7, helping to identify favorable intestinal environments for the development of severe disease.
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Dagenais M, Gerlach JQ, Geary TG, Long T. Sugar Coating: Utilisation of Host Serum Sialoglycoproteins by Schistosoma mansoni as a Potential Immune Evasion Mechanism. Pathogens 2022; 11:pathogens11040426. [PMID: 35456101 PMCID: PMC9030049 DOI: 10.3390/pathogens11040426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/26/2022] [Accepted: 03/30/2022] [Indexed: 11/21/2022] Open
Abstract
Parasitic helminths resort to various mechanisms to evade and modulate their host’s immune response, several of which have been described for Schistosoma mansoni. We recently reported the presence of sialic acid residues on the surface of adult S. mansoni extracellular vesicles (EVs). We now report that these sialylated molecules are mammalian serum proteins. In addition, our data suggest that most sialylated EV-associated proteins do not elicit a humoral response upon injection into mice, or in sera obtained from infected animals. Sialic acids frequently terminate glycans on the surface of vertebrate cells, where they serve important functions in physiological processes such as cell adhesion and signalling. Interestingly, several pathogens have evolved ways to mimic or utilise host sialic acid beneficially by coating their own proteins, thereby facilitating cell invasion and providing protection from host immune effectors. Together, our results indicate that S. mansoni EVs are coated with host glycoproteins, which may contribute to immune evasion by masking antigenic sites, protecting EVs from removal from serum and aiding in cell adhesion and entry to exert their functions.
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Affiliation(s)
- Maude Dagenais
- Institute of Parasitology, McGill University, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada; (T.G.G.); (T.L.)
- Correspondence:
| | - Jared Q. Gerlach
- Advanced Glycoscience Research Cluster, National University of Ireland-Galway, H91 TK33 Galway, Ireland;
| | - Timothy G. Geary
- Institute of Parasitology, McGill University, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada; (T.G.G.); (T.L.)
- Microbes and Pathogen Biology, The Institute for Global Food Security, School of Biological Sciences, Queen’s University-Belfast, Belfast BT9 5DL, UK
| | - Thavy Long
- Institute of Parasitology, McGill University, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada; (T.G.G.); (T.L.)
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Arokiyaraj C, Tamilarasan K, Manikandan R, Janarthanan S. Purification and structural characterization of lectin with antibacterial and anticancer properties from grubs of hide beetle, Dermestes frischii. Int J Biol Macromol 2022; 203:312-332. [PMID: 35074334 DOI: 10.1016/j.ijbiomac.2022.01.099] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/27/2021] [Accepted: 01/14/2022] [Indexed: 12/27/2022]
Abstract
Lectins or haemagglutinins are diverse classes of non-immune proteins; they bind to carbohydrates and are abundant in nature. In the present study, a coleopteran lectin from grubs of hide beetle, Dermestes frischii called DFL, was purified by glutaraldehyde (fixative-agent) fixed hen erythrocytes and characterized further for its functional properties. The purified DFL was stable between pH range 5 to 9 and heat-stable up to 50C. It was insensitive to EDTA and did not require any divalent cations. DFL native molecular mass was approximately 69 kDa with three different polypeptide subunits of 33 (pI ~4.4), 22 (pI ~6) and 14 (pI ~4.4) kDa. Haemagglutinating activity of DFL was highly inhibited by N-acetyl-D-glucosamine. DFL partial peptide sequences obtained from peptide mass fingerprinting experiments matched with amino acid sequences of lectins from different organisms confirmed its nature. Biological properties of purified DFL namely antibacterial and bacterial agglutination experiments revealed that DFL have both the effects against laboratory cultures of Aeromonas hydrophila, Enterococcus faecalis, Escherichia coli and habitat bacterial isolates of Staphylococcus cohnii and Bacillus cereus. In addition, the DFL exhibited substantial anticancer properties against HeLa cells. These results concluded that purified DFL could serve as a potent therapeutic agent for various biomedical applications.
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Affiliation(s)
- Charles Arokiyaraj
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India
| | | | - Ramar Manikandan
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Sundaram Janarthanan
- Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, India.
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Bessaiah H, Anamalé C, Sung J, Dozois CM. What Flips the Switch? Signals and Stress Regulating Extraintestinal Pathogenic Escherichia coli Type 1 Fimbriae (Pili). Microorganisms 2021; 10:5. [PMID: 35056454 PMCID: PMC8777976 DOI: 10.3390/microorganisms10010005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/18/2022] Open
Abstract
Pathogens are exposed to a multitude of harmful conditions imposed by the environment of the host. Bacterial responses against these stresses are pivotal for successful host colonization and pathogenesis. In the case of many E. coli strains, type 1 fimbriae (pili) are an important colonization factor that can contribute to diseases such as urinary tract infections and neonatal meningitis. Production of type 1 fimbriae in E. coli is dependent on an invertible promoter element, fimS, which serves as a phase variation switch determining whether or not a bacterial cell will produce type 1 fimbriae. In this review, we present aspects of signaling and stress involved in mediating regulation of type 1 fimbriae in extraintestinal E. coli; in particular, how certain regulatory mechanisms, some of which are linked to stress response, can influence production of fimbriae and influence bacterial colonization and infection. We suggest that regulation of type 1 fimbriae is potentially linked to environmental stress responses, providing a perspective for how environmental cues in the host and bacterial stress response during infection both play an important role in regulating extraintestinal pathogenic E. coli colonization and virulence.
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Affiliation(s)
- Hicham Bessaiah
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Carole Anamalé
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
| | - Jacqueline Sung
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
- Department of Microbiology and Immunology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Charles M. Dozois
- Institut National de Recherche Scientifique (INRS)-Centre Armand-Frappier Santé Biotechnologie, Laval, QC H7V 1B7, Canada; (H.B.); (C.A.); (J.S.)
- Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Saint-Hyacinthe, QC J2S 2M2, Canada
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How far is it from infant formula to human milk? A look at the human milk oligosaccharides. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2021.09.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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8
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Lupo F, Ingersoll MA, Pineda MA. The glycobiology of uropathogenic E. coli infection: the sweet and bitter role of sugars in urinary tract immunity. Immunology 2021; 164:3-14. [PMID: 33763853 PMCID: PMC8358714 DOI: 10.1111/imm.13330] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/02/2021] [Accepted: 03/07/2021] [Indexed: 12/25/2022] Open
Abstract
Urinary tract infections (UTI) are among the most prevalent infectious diseases and the most common cause of nosocomial infections, worldwide. Uropathogenic E. coli (UPEC) are responsible for approximately 80% of all UTI, which most commonly affect the bladder. UPEC colonize the urinary tract by ascension of the urethra, followed by cell invasion, and proliferation inside and outside urothelial cells, thereby causing symptomatic infections and quiescent intracellular reservoirs that may lead to recurrence. Sugars, or glycans, are key molecules for host–pathogen interactions, and UTI are no exception. Surface glycans regulate many of the events associated with UPEC adhesion and infection, as well as induction of the host immune response. While the bacterial protein FimH binds mannose‐containing host glycoproteins to initiate infection and UPEC‐secreted polysaccharides block immune mechanisms to favour intracellular replication, host glycans on the urothelial surface and on secreted glycoproteins prevent or limit infection by inhibiting UPEC adhesion. Given the importance of glycans during UTI, here we review the glycobiology of UPEC infection to highlight fundamental sugar‐mediated processes of immunological interest for their potential clinical applications. Interdisciplinary approaches incorporating glycomics and infection biology may help to develop novel non‐antibiotic‐based therapeutic strategies for bacterial infections as the spread of antimicrobial‐resistant uropathogens is currently threatening modern healthcare systems.
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Affiliation(s)
- Federico Lupo
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | | | - Miguel A Pineda
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
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Sponge-associated sp . RM66 metabolome induction with N-acetylglucosamine: Antibacterial, antifungal and anti-trypanosomal activities. Saudi J Biol Sci 2021; 28:4691-4698. [PMID: 34354456 PMCID: PMC8324951 DOI: 10.1016/j.sjbs.2021.04.082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 11/22/2022] Open
Abstract
The marine sponge Amphimedon sp., collected from Hurghada (Egypt) was investigated for its sponge-derived actinomycetes diversity. Nineteen actinomycetes were cultivated and phylogenetically identified using 16S rDNA gene sequencing were carried out. The strains belong to genera Kocuria, Dietzia, Micrococcus, Microbacterium and Streptomyces. Many silent biosynthetic genes clusters were investigated using genome sequencing of actinomycete strains and has revealed in particular the genus Streptomyces that has indicated their exceptional capacity for the secondary metabolites production that not observed under classical cultivation conditions. In this study, the effect of N-acetylglucosamine on the metabolome of Streptomyces sp. RM66 was investigated using three actinomycetes media (ISP2, M1 and MA). In total, twelve extracts were produced using solid and liquid fermentation approaches. Liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS) data were analysed using metabolomics tools to compare natural product production across all crude extracts. Our study highlighted the elicitation effect of N-acetylglucosamine on the secondary metabolite profiles of Streptomyces sp. RM66. These results highlight the of N-acetylglucosamine application as an elicitor to induce the cryptic metabolites and for increasing the chemical diversity. All the twelve extracts were tested for their antibacterial activity was tested against Staphylococcus aureus NCTC 8325, antifungal activity against Candida albicans 5314 (ATCC 90028) and anti-trypanosomal activity against Trypanosoma brucei brucei. Extract St1 showed the most potent one with activities 2.3, 3.2 and 4.7 ug/ml as antibacterial, antifungal and anti-trypanosomal, respectively.
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10
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Fischer-Tlustos AJ, Hertogs K, van Niekerk JK, Nagorske M, Haines DM, Steele MA. Oligosaccharide concentrations in colostrum, transition milk, and mature milk of primi- and multiparous Holstein cows during the first week of lactation. J Dairy Sci 2020; 103:3683-3695. [PMID: 32037163 DOI: 10.3168/jds.2019-17357] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 12/06/2019] [Indexed: 12/25/2022]
Abstract
The objective of this study was to characterize the oligosaccharide (OS) profile of colostrum and transition milk from primiparous (Pp, n = 10) and multiparous (Mp, n = 10) Holstein cows. The experiment was conducted on a commercial dairy farm, where cows were assigned to the study at calving. Colostrum (milking 1) was collected at 5.3 ± 0.7 h after parturition, followed by collection of milkings 2 through 6, milkings 8, 10, 12, and 14 at 0500 and 1600 h each day. Samples were analyzed for OS concentrations using liquid chromatography-mass spectrometry and for IgG and milk components. Concentration of IgG was highest in colostrum and milking 2. Colostral IgG concentration was less in Pp cows than in Mp cows (82.1 ± 3.1 vs. 106.1 ± 16.2 mg/mL). Colostrum and milkings 2 and 3 had 3'-sialyllactose and 6'-sialyllactose concentrations greater than those of mature milk (milkings 8+). For colostrum and milking 2, 6'-sialyllactosamine concentrations were higher than all other milkings, while disialyllactose was only higher in colostrum. In addition, 3'-sialyllactose was the most abundant OS in colostrum and milkings 2 and 3 compared with all other OS. A parity difference was observed for 6'-sialyllactosamine, with Mp having a higher concentration over the first 7 d in milk than Pp (46.4 ± 8.7 vs. 16.9 ± 3.2 μg/mL). Similar results were observed between milkings for OS yields. Parity differences were detected for 3'-sialyllactose, 6'-sialyllactose, and 6'-sialyllactosamine yield, with Mp yield being greater than Pp over the first 7 d in milk. These findings demonstrate that colostrum and transition milk contain elevated concentrations of certain OS compared with mature milk and suggest further research should be conducted regarding the potential benefits of OS in colostrum and transition milk when fed to newborn calves.
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Affiliation(s)
- A J Fischer-Tlustos
- Department of Animal Biosciences, Animal Science and Nutrition, University of Guelph, Guelph, ON, Canada N1G 1Y2
| | - K Hertogs
- Animal Nutrition Group, Department of Animal Science, Wageningen University & Research, Wageningen 6708, the Netherlands
| | - J K van Niekerk
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5
| | - M Nagorske
- The Saskatoon Colostrum Company Ltd., Saskatoon, SK, Canada S7K 6A2
| | - D M Haines
- The Saskatoon Colostrum Company Ltd., Saskatoon, SK, Canada S7K 6A2; Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4
| | - M A Steele
- Department of Animal Biosciences, Animal Science and Nutrition, University of Guelph, Guelph, ON, Canada N1G 1Y2; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5.
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Sialic acid and biology of life: An introduction. SIALIC ACIDS AND SIALOGLYCOCONJUGATES IN THE BIOLOGY OF LIFE, HEALTH AND DISEASE 2020. [PMCID: PMC7153325 DOI: 10.1016/b978-0-12-816126-5.00001-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sialic acids are important molecule with high structural diversity. They are known to occur in higher animals such as Echinoderms, Hemichordata, Cephalochorda, and Vertebrata and also in other animals such as Platyhelminthes, Cephalopoda, and Crustaceae. Plants are known to lack sialic acid. But they are reported to occur in viruses, bacteria, protozoa, and fungi. Deaminated neuraminic acid although occurs in vertebrates and bacteria, is reported to occur in abundance in the lower vertebrates. Sialic acids are mostly located in terminal ends of glycoproteins and glycolipids, capsular and tissue polysialic acids, bacterial lipooligosaccharides/polysaccharides, and in different forms that dictate their role in biology. Sialic acid play important roles in human physiology of cell-cell interaction, communication, cell-cell signaling, carbohydrate-protein interactions, cellular aggregation, development processes, immune reactions, reproduction, and in neurobiology and human diseases in enabling the infection process by bacteria and virus, tumor growth and metastasis, microbiome biology, and pathology. It enables molecular mimicry in pathogens that allows them to escape host immune responses. Recently sialic acid has found role in therapeutics. In this chapter we have highlighted the (i) diversity of sialic acid, (ii) their occurrence in the diverse life forms, (iii) sialylation and disease, and (iv) sialic acid and therapeutics.
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Bessaiah H, Pokharel P, Habouria H, Houle S, Dozois CM. yqhG Contributes to Oxidative Stress Resistance and Virulence of Uropathogenic Escherichia coli and Identification of Other Genes Altering Expression of Type 1 Fimbriae. Front Cell Infect Microbiol 2019; 9:312. [PMID: 31555608 PMCID: PMC6727828 DOI: 10.3389/fcimb.2019.00312] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/16/2019] [Indexed: 12/15/2022] Open
Abstract
Urinary tract infections (UTIs) are common bacterial infections and the vast majority of UTIs are caused by extraintestinal pathogenic Escherichia coli (ExPEC) strains referred to as uropathogenic E. coli (UPEC). Successful colonization of the human urinary tract by UPEC is mediated by secreted or surface exposed virulence factors-toxins, iron transport systems, and adhesins, such as type 1 fimbriae (pili). To identify factors involved in the expression of type 1 fimbriae, we constructed a chromosomal transcriptional reporter consisting of lux under the control of the fimbrial promoter region, fimS and this construct was inserted into the reference UPEC strain CFT073 genome at the attTn7 site. This fimS reporter strain was used to generate a Tn10 transposon mutant library, coupled with high-throughput sequencing to identify genes that affect the expression of type 1 fimbriae. Transposon insertion sites were linked to genes involved in protein fate and synthesis, energy metabolism, adherence, transcriptional regulation, and transport. We showed that YqhG, a predicted periplasmic protein, is one of the important mediators that contribute to the decreased expression of type 1 fimbriae in UPEC strain CFT073. The ΔyqhG mutant had reduced expression of type 1 fimbriae and a decreased capacity to colonize the murine urinary tract. Reduced expression of type 1 fimbriae correlated with an increased bias for orientation of the fim switch in the OFF position. Interestingly, the ΔyqhG mutant was more motile than the WT strain and was also significantly more sensitive to hydrogen peroxide. Taken together, loss of yqhG may decrease virulence in the urinary tract due to a decrease in production of type 1 fimbriae and a greater sensitivity to oxidative stress.
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Affiliation(s)
- Hicham Bessaiah
- INRS-Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
- CRIPA-Centre de Recherche en Infectiologie Porcine et Avicole, Saint-Hyacinthe, QC, Canada
| | - Pravil Pokharel
- INRS-Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
- CRIPA-Centre de Recherche en Infectiologie Porcine et Avicole, Saint-Hyacinthe, QC, Canada
| | - Hajer Habouria
- INRS-Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
- CRIPA-Centre de Recherche en Infectiologie Porcine et Avicole, Saint-Hyacinthe, QC, Canada
| | - Sébastien Houle
- INRS-Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
- CRIPA-Centre de Recherche en Infectiologie Porcine et Avicole, Saint-Hyacinthe, QC, Canada
| | - Charles M. Dozois
- INRS-Centre Armand-Frappier Santé Biotechnologie, Laval, QC, Canada
- CRIPA-Centre de Recherche en Infectiologie Porcine et Avicole, Saint-Hyacinthe, QC, Canada
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13
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Shimada T, Ogasawara H, Ishihama A. Single-target regulators form a minor group of transcription factors in Escherichia coli K-12. Nucleic Acids Res 2019. [PMID: 29529243 PMCID: PMC5934670 DOI: 10.1093/nar/gky138] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The identification of regulatory targets of all TFs is critical for understanding the entire network of the genome regulation. The lac regulon of Escherichia coli K-12 W3110 is composed of the lacZYA operon and its repressor lacI gene, and has long been recognized as the seminal model of transcription regulation in bacteria with only one highly preferred target. After the Genomic SELEX screening in vitro of more than 200 transcription factors (TFs) from E. coli K-12, however, we found that most TFs regulate multiple target genes. With respect to the number of regulatory targets, a total of these 200 E. coli TFs form a hierarchy ranging from a single target to as many as 1000 targets. Here we focus a total of 13 single-target TFs, 9 known TFs (BetI, KdpE, LacI, MarR, NanR, RpiR, TorR, UlaR and UxuR) and 4 uncharacterized TFs (YagI, YbaO, YbiH and YeaM), altogether forming only a minor group of TFs in E. coli. These single-target TFs were classified into three groups based on their functional regulation.
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Affiliation(s)
- Tomohiro Shimada
- Meiji University, School of Agriculture, Kawasaki, Kanagawa 214-8571, Japan
| | - Hiroshi Ogasawara
- Shinshu University, Research Center for Supports to Advanced Science, Division of Gene Research, Ueda, Nagano 386-8567, Japan.,Shinshu University, Research Center for Fungal and Microbial Dynamism, Kamiina, Nagano 399-4598, Japan
| | - Akira Ishihama
- Hosei University, Micro-Nano Technology Research Center, Koganei, Tokyo 184-8584, Japan
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14
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Di Somma A, Caterino M, Soni V, Agarwal M, di Pasquale P, Zanetti S, Molicotti P, Cannas S, Nandicoori VK, Duilio A. The bifunctional protein GlmU is a key factor in biofilm formation induced by alkylating stress in Mycobacterium smegmatis. Res Microbiol 2019; 170:171-181. [DOI: 10.1016/j.resmic.2019.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 03/21/2019] [Accepted: 03/21/2019] [Indexed: 10/27/2022]
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15
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Li X, Li X, Zhu J, Wang H, Lu C. Carbamothioic S-acid derivative and kigamicins, the activated production of silent metabolites in Amycolatopsis alba DSM 44262Δ abm9 elicited by N-acetyl-D-glucosamine. Nat Prod Res 2019; 34:3514-3521. [PMID: 30784305 DOI: 10.1080/14786419.2019.1574783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
One new carbamothioic S-acid derivative (1) and five known kigamicin derivatives (2-6) were isolated from the fermentation extract of Amycolatopsis alba DSM 44262Δabm9 elicited by N-acetyl-D-glucosamine. HPLC-DAD-UV analyses indicated that the DSM 44262Δabm9 strain did not produce these metabolites originally and the production of 1-6 was induced by adding 25 mM N-acetyl-D-glucosamine in the culture medium. The structures of 1-6 were identified on the basis of NMR spectroscopic data and high-resolution ESIMS. These results highlight that addition of N-acetyl-D-glucosamine in the microbial culture medium could activate cryptic gene expression, induce and increase the production of new or known secondary metabolites.
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Affiliation(s)
- Xiaomei Li
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan, Shandong, China
| | - Xiaoman Li
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan, Shandong, China
| | - Jing Zhu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong, China
| | - Haoxin Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong, China
| | - Chunhua Lu
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan, Shandong, China
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16
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Nilsson I, Prathapam R, Grove K, Lapointe G, Six DA. The sialic acid transporter NanT is necessary and sufficient for uptake of 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) and its azido analog in Escherichia coli. Mol Microbiol 2018; 110:204-218. [PMID: 30076772 DOI: 10.1111/mmi.14098] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2018] [Indexed: 01/31/2023]
Abstract
3-Deoxy-d-manno-oct-2-ulosonic acid (Kdo) is an essential component of lipopolysaccharides (LPS) in the Gram-negative bacterial outer membrane. Metabolic labeling of Escherichia coli LPS with 8-azido-3,8-dideoxy-d-manno-oct-2-ulosonic acid (Kdo-N3 ) has been reported but is inefficient. For optimization, it is important to understand how exogenous Kdo-N3 enters the cytoplasm. Based on similarities between Kdo and sialic acids, we proposed and verified that the sialic acid transporter NanT imports exogenous Kdo-N3 into E. coli. We demonstrated that E. coli ΔnanT were not labeled with Kdo-N3 , while expression of NanT in the ΔnanT mutant restored Kdo-N3 incorporation. Induced NanT expression in a strain lacking Kdo biosynthesis led to higher exogenous Kdo incorporation and restoration of full-length core-LPS, suggesting that NanT also transports Kdo. While Kdo-N3 incorporation was observed in strains having NanT, it was not detected in Pseudomonas aeruginosa and Acinetobacter baumannii, which lack nanT. However, heterologous expression of E. coli NanT in P. aeruginosa enabled Kdo-N3 incorporation and labeling, though this led to abnormal morphology and growth arrest. NanT seems to define which bacteria can be labeled with Kdo-N3 , provides opportunities to enhance Kdo-N3 labeling efficiency and spectrum, and raises the possibility of Kdo biosynthetic bypass where exogenous Kdo is present, perhaps even in vivo.
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Affiliation(s)
- Inga Nilsson
- Department of Infectious Diseases, Novartis Institutes for BioMedical Research, Emeryville, CA, 94608, USA
| | - Ramadevi Prathapam
- Department of Infectious Diseases, Novartis Institutes for BioMedical Research, Emeryville, CA, 94608, USA
| | - Kerri Grove
- Department of Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, CA, 94608, USA
| | - Guillaume Lapointe
- Department of Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, CA, 94608, USA
| | - David A Six
- Department of Infectious Diseases, Novartis Institutes for BioMedical Research, Emeryville, CA, 94608, USA
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Sicard JF, Vogeleer P, Le Bihan G, Rodriguez Olivera Y, Beaudry F, Jacques M, Harel J. N-Acetyl-glucosamine influences the biofilm formation of Escherichia coli. Gut Pathog 2018; 10:26. [PMID: 29977346 PMCID: PMC6013987 DOI: 10.1186/s13099-018-0252-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/18/2018] [Indexed: 12/14/2022] Open
Abstract
Background The intestinal mucous layer is a physical barrier that limits the contact between bacteria and host epithelial cells. There is growing evidence that microbiota-produced metabolites can also be specifically sensed by gut pathogens as signals to induce or repress virulence genes. Many E. coli, including adherent and invasive (AIEC) strains, can form biofilm. This property can promote their intestinal colonization and resistance to immune mechanisms. We sought to evaluate the impact of mucus-derived sugars on biofilm formation of E. coli. Results We showed that the mucin sugar N-acetyl-glucosamine (NAG) can reduce biofilm formation of AIEC strain LF82. We demonstrated that the inactivation of the regulatory protein NagC, by addition of NAG or by mutation of nagC gene, reduced the biofilm formation of LF82 in static condition. Interestingly, real-time monitoring of biofilm formation of LF82 using microfluidic system showed that the mutation of nagC impairs the early process of biofilm development of LF82. Thus, NAG sensor NagC is involved in the early steps of biofilm formation of AIEC strain LF82 under both static and dynamic conditions. Its implication is partly due to the activation of type 1 fimbriae. NAG can also influence biofilm formation of other intestinal E. coli strains. Conclusions This study highlights how catabolism can be involved in biofilm formation of E. coli. Mucus-derived sugars can influence virulence properties of pathogenic E. coli and this study will help us better understand the mechanisms used to prevent colonization of the intestinal mucosa by pathogens. Electronic supplementary material The online version of this article (10.1186/s13099-018-0252-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jean-Félix Sicard
- 1Groupe de Recherche sur les Maladies Infectieuses en Production Animale, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 2M2 Canada
| | - Philippe Vogeleer
- 1Groupe de Recherche sur les Maladies Infectieuses en Production Animale, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 2M2 Canada
| | - Guillaume Le Bihan
- 1Groupe de Recherche sur les Maladies Infectieuses en Production Animale, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 2M2 Canada
| | - Yaindrys Rodriguez Olivera
- 1Groupe de Recherche sur les Maladies Infectieuses en Production Animale, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 2M2 Canada
| | - Francis Beaudry
- 1Groupe de Recherche sur les Maladies Infectieuses en Production Animale, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 2M2 Canada
| | - Mario Jacques
- 2Regroupement de Recherche Pour un Lait de Qualité Optimale (Op+Lait), Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2 Canada
| | - Josée Harel
- 1Groupe de Recherche sur les Maladies Infectieuses en Production Animale, Centre de Recherche en Infectiologie Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 2M2 Canada
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18
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GntR Family Regulator DasR Controls Acetate Assimilation by Directly Repressing the acsA Gene in Saccharopolyspora erythraea. J Bacteriol 2018; 200:JB.00685-17. [PMID: 29686136 DOI: 10.1128/jb.00685-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/16/2018] [Indexed: 01/09/2023] Open
Abstract
The GntR family regulator DasR controls the transcription of genes involved in chitin and N-acetylglucosamine (GlcNAc) metabolism in actinobacteria. GlcNAc is catabolized to ammonia, fructose-6-phosphate (Fru-6P), and acetate, which are nitrogen and carbon sources. In this work, a DasR-responsive element (dre) was observed in the upstream region of acsA1 in Saccharopolyspora erythraea This gene encodes acetyl coenzyme A (acetyl-CoA) synthetase (Acs), an enzyme that catalyzes the conversion of acetate into acetyl-CoA. We found that DasR repressed the transcription of acsA1 in response to carbon availability, especially with GlcNAc. Growth inhibition was observed in a dasR-deleted mutant (ΔdasR) in the presence of GlcNAc in minimal medium containing 10 mM acetate, a condition under which Acs activity is critical to growth. These results demonstrate that DasR controls acetate assimilation by directly repressing the transcription of the acsA1 gene and performs regulatory roles in the production of intracellular acetyl-CoA in response to GlcNAc.IMPORTANCE Our work has identified the DasR GlcNAc-sensing regulator that represses the generation of acetyl-CoA by controlling the expression of acetyl-CoA synthetase, an enzyme responsible for acetate assimilation in S. erythraea The finding provides the first insights into the importance of DasR in the regulation of acetate metabolism, which encompasses the regulatory network between nitrogen and carbon metabolism in actinobacteria, in response to environmental changes.
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19
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Rossi E, Cimdins A, Lüthje P, Brauner A, Sjöling Å, Landini P, Römling U. "It's a gut feeling" - Escherichia coli biofilm formation in the gastrointestinal tract environment. Crit Rev Microbiol 2017; 44:1-30. [PMID: 28485690 DOI: 10.1080/1040841x.2017.1303660] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Escherichia coli can commonly be found, either as a commensal, probiotic or a pathogen, in the human gastrointestinal (GI) tract. Biofilm formation and its regulation is surprisingly variable, although distinct regulatory pattern of red, dry and rough (rdar) biofilm formation arise in certain pathovars and even clones. In the GI tract, environmental conditions, signals from the host and from commensal bacteria contribute to shape E. coli biofilm formation within the multi-faceted multicellular communities in a complex and integrated fashion. Although some major regulatory networks, adhesion factors and extracellular matrix components constituting E. coli biofilms have been recognized, these processes have mainly been characterized in vitro and in the context of interaction of E. coli strains with intestinal epithelial cells. However, direct observation of E. coli cells in situ, and the vast number of genes encoding surface appendages on the core or accessory genome of E. coli suggests the complexity of the biofilm process to be far from being fully understood. In this review, we summarize biofilm formation mechanisms of commensal, probiotic and pathogenic E. coli in the context of the gastrointestinal tract.
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Affiliation(s)
- Elio Rossi
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy.,b Novo Nordisk Center for Biosustainabiliy , Technical University of Denmark , Kgs. Lyngby , Denmark
| | - Annika Cimdins
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,d Institute of Hygiene, University of Münster , Münster , Germany
| | - Petra Lüthje
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,e Division of Clinical Microbiology, Department of Laboratory Medicine , Karolinska Institutet and Karolinska University Hospital Huddinge , Stockholm , Sweden
| | - Annelie Brauner
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Åsa Sjöling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Paolo Landini
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy
| | - Ute Römling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
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20
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Douëllou T, Montel M, Thevenot Sergentet D. Invited review: Anti-adhesive properties of bovine oligosaccharides and bovine milk fat globule membrane-associated glycoconjugates against bacterial food enteropathogens. J Dairy Sci 2017; 100:3348-3359. [DOI: 10.3168/jds.2016-11611] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 12/14/2016] [Indexed: 12/11/2022]
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21
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Dashti Y, Grkovic T, Abdelmohsen UR, Hentschel U, Quinn RJ. Actinomycete Metabolome Induction/Suppression with N-Acetylglucosamine. JOURNAL OF NATURAL PRODUCTS 2017; 80:828-836. [PMID: 28355070 DOI: 10.1021/acs.jnatprod.6b00673] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The metabolite profiles of three sponge-derived actinomycetes, namely, Micromonospora sp. RV43, Rhodococcus sp. RV157, and Actinokineospora sp. EG49 were investigated after elicitation with N-acetyl-d-glucosamine. 1H NMR fingerprint methodology was utilized to study the differences in the metabolic profiles of the bacterial extracts before and after elicitation. Our study found that the addition of N-acetyl-d-glucosamine modified the secondary metabolite profiles of the three investigated actinomycete isolates. N-Acetyl-d-glucosamine induced the production of 3-formylindole (11) and guaymasol (12) in Micromonospora sp. RV43, the siderophore bacillibactin 16, and surfactin antibiotic 17 in Rhodococcus sp. RV157 and increased the production of minor metabolites actinosporins E-H (21-24) in Actinokineospora sp. EG49. These results highlight the use of NMR fingerprinting to detect changes in metabolism following addition of N-acetyl-d-glucosamine. N-Acetyl-d-glucosamine was shown to have multiple effects including suppression of metabolites, induction of new metabolites, and increased production of minor compounds.
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Affiliation(s)
- Yousef Dashti
- Eskitis Institute for Drug Discovery, Griffith University , Brisbane, QLD 4111 Australia
| | - Tanja Grkovic
- Eskitis Institute for Drug Discovery, Griffith University , Brisbane, QLD 4111 Australia
| | - Usama Ramadan Abdelmohsen
- Department of Botany II, Julius-von-Sachs Institute for Biological Sciences, University of Würzburg , Julius-von-Sachs-Platz 3, D-97082 Würzburg, Germany
| | - Ute Hentschel
- Department of Botany II, Julius-von-Sachs Institute for Biological Sciences, University of Würzburg , Julius-von-Sachs-Platz 3, D-97082 Würzburg, Germany
| | - Ronald J Quinn
- Eskitis Institute for Drug Discovery, Griffith University , Brisbane, QLD 4111 Australia
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22
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Le Bihan G, Sicard JF, Garneau P, Bernalier-Donadille A, Gobert AP, Garrivier A, Martin C, Hay AG, Beaudry F, Harel J, Jubelin G. The NAG Sensor NagC Regulates LEE Gene Expression and Contributes to Gut Colonization by Escherichia coli O157:H7. Front Cell Infect Microbiol 2017; 7:134. [PMID: 28484684 PMCID: PMC5401889 DOI: 10.3389/fcimb.2017.00134] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 03/31/2017] [Indexed: 11/16/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 are human pathogens responsible for bloody diarrhea and renal failures. EHEC employ a type 3 secretion system to attach directly to the human colonic epithelium. This structure is encoded by the locus of enterocyte effacement (LEE) whose expression is regulated in response to specific nutrients. In this study, we show that the mucin-derived sugars N-acetylglucosamine (NAG) and N-acetylneuraminic acid (NANA) inhibit EHEC adhesion to epithelial cells through down-regulation of LEE expression. The effect of NAG and NANA is dependent on NagC, a transcriptional repressor of the NAG catabolism in E. coli. We show that NagC is an activator of the LEE1 operon and a critical regulator for the colonization of mice intestine by EHEC. Finally, we demonstrate that NAG and NANA as well as the metabolic activity of Bacteroides thetaiotaomicron affect the in vivo fitness of EHEC in a NagC-dependent manner. This study highlights the role of NagC in coordinating metabolism and LEE expression in EHEC and in promoting EHEC colonization in vivo.
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Affiliation(s)
- Guillaume Le Bihan
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Jean-Félix Sicard
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Philippe Garneau
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | | | - Alain P Gobert
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
| | - Annie Garrivier
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
| | - Christine Martin
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
| | - Anthony G Hay
- Department of Microbiology, Cornell UniversityIthaca, NY, USA
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animal du Québec, Département de Biomédecine Vétérinaire, Faculté de Médecine Vétérinaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Josée Harel
- Faculté de Médecine Vétérinaire, Centre de Recherche en Infectiologie Porcine et Aviaire, Université de MontréalSaint-Hyacinthe, QC, Canada
| | - Grégory Jubelin
- INRA, Université Clermont Auvergne, MEDISClermont-Ferrand, France
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Genomewide Dam Methylation in Escherichia coli during Long-Term Stationary Phase. mSystems 2016; 1:mSystems00130-16. [PMID: 27981240 PMCID: PMC5155068 DOI: 10.1128/msystems.00130-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/04/2016] [Indexed: 11/20/2022] Open
Abstract
DNA methylation in prokaryotes is widespread. The most common modification of the genome is the methylation of adenine at the N-6 position. In Escherichia coli K-12 and many gammaproteobacteria, this modification is catalyzed by DNA adenine methyltransferase (Dam) at the GATC consensus sequence and is known to modulate cellular processes including transcriptional regulation of gene expression, initiation of chromosomal replication, and DNA mismatch repair. While studies thus far have focused on the motifs associated with methylated adenine (meA), the frequency of meA across the genome, and temporal dynamics during early periods of incubation, here we conduct the first study on the temporal dynamics of adenine methylation in E. coli by Dam throughout all five phases of the bacterial life cycle in the laboratory. Using single-molecule real-time sequencing, we show that virtually all GATC sites are significantly methylated over time; nearly complete methylation of the chromosome was confirmed by mass spectroscopy analysis. However, we also detect 66 sites whose methylation patterns change significantly over time within a population, including three sites associated with sialic acid transport and catabolism, suggesting a potential role for Dam regulation of these genes; differential expression of this subset of genes was confirmed by quantitative real-time PCR. Further, we show significant growth defects of the dam mutant during long-term stationary phase (LTSP). Together these data suggest that the cell places a high premium on fully methylating the chromosome and that alterations in methylation patterns may have significant impact on patterns of transcription, maintenance of genetic fidelity, and cell survival. IMPORTANCE While it has been shown that methylation remains relatively constant into early stationary phase of E. coli, this study goes further through death phase and long-term stationary phase, a unique time in the bacterial life cycle due to nutrient limitation and strong selection for mutants with increased fitness. The absence of methylation at GATC sites can influence the mutation frequency within a population due to aberrant mismatch repair. Therefore, it is important to investigate the methylation status of GATC sites in an environment where cells may not prioritize methylation of the chromosome. This study demonstrates that chromosome methylation remains a priority even under conditions of nutrient limitation, indicating that continuous methylation at GATC sites could be under positive selection.
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Kimyon Ö, Ulutürk ZI, Nizalapur S, Lee M, Kutty SK, Beckmann S, Kumar N, Manefield M. N-Acetylglucosamine Inhibits LuxR, LasR and CviR Based Quorum Sensing Regulated Gene Expression Levels. Front Microbiol 2016; 7:1313. [PMID: 27602027 PMCID: PMC4993992 DOI: 10.3389/fmicb.2016.01313] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/09/2016] [Indexed: 12/19/2022] Open
Abstract
N-acetyl glucosamine, the monomer of chitin, is an abundant source of carbon and nitrogen in nature as it is the main component and breakdown product of many structural polymers. Some bacteria use N-acyl-L-homoserine lactone (AHL) mediated quorum sensing (QS) to regulate chitinase production in order to catalyze the cleavage of chitin polymers into water soluble N-acetyl-D-glucosamine (NAG) monomers. In this study, the impact of NAG on QS activities of LuxR, LasR, and CviR regulated gene expression was investigated by examining the effect of NAG on QS regulated green fluorescent protein (GFP), violacein and extracellular chitinase expression. It was discovered that NAG inhibits AHL dependent gene transcription in AHL reporter strains within the range of 50-80% reduction at low millimolar concentrations (0.25-5 mM). Evidence is presented supporting a role for both competitive inhibition at the AHL binding site of LuxR type transcriptional regulators and catabolite repression. Further, this study shows that NAG down-regulates CviR induced violacein production while simultaneously up-regulating CviR dependent extracellular enzymes, suggesting that an unknown NAG dependent regulatory component influences phenotype expression. The quorum sensing inhibiting activity of NAG also adds to the list of compounds with known quorum sensing inhibiting activities.
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Affiliation(s)
- Önder Kimyon
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW, Australia
| | - Zehra I Ulutürk
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW, Australia
| | | | - Matthew Lee
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW, Australia
| | - Samuel K Kutty
- School of Chemistry, University of New South Wales, Sydney NSW, Australia
| | - Sabrina Beckmann
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW, Australia
| | - Naresh Kumar
- School of Chemistry, University of New South Wales, Sydney NSW, Australia
| | - Mike Manefield
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW, Australia
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Human milk oligosaccharides: The role in the fine-tuning of innate immune responses. Carbohydr Res 2016; 432:62-70. [PMID: 27448325 DOI: 10.1016/j.carres.2016.07.009] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/05/2016] [Accepted: 07/06/2016] [Indexed: 01/12/2023]
Abstract
In order to secure the health of newborns over the period of immune immaturity during the first months of life, a mother provides her offspring with passive protection: bioactive molecules transferred through the placenta and breast milk. It is well known that human milk contains immunoglobulins (Ig), immune cells and diverse cytokines, which affect newborn directly or indirectly and contribute to the maturation of the immune system. However, in addition to the above-stated molecules, human milk oligosaccharides (HMOs), a complex mixture of free indigestible carbohydrates with multiple functions, play exceptional roles in the functioning of the infants' immune system. These biological molecules have been studied over decades, however, interest in HMOs does not seem to have abated. Although biological activities of oligosaccharides from human milk have been explicitly reviewed, information regarding the role of HMOs in inflammation remains rather fragmented. The purpose of this review is to compile existing knowledge about the role of certain species of HMOs, including fucosylated, galactosylated and sialylated oligosaccharides, and their signaling pathways in immunity and inflammation. The advances in applying this information to the treatment of diseases in infants as well as adults were also reviewed here.
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26
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Zhao L, Huang Y, Hu J, Zhou H, Adeleye AS, Keller AA. (1)H NMR and GC-MS Based Metabolomics Reveal Defense and Detoxification Mechanism of Cucumber Plant under Nano-Cu Stress. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:2000-10. [PMID: 26751164 DOI: 10.1021/acs.est.5b05011] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Because copper nanoparticles are being increasingly used in agriculture as pesticides, it is important to assess their potential implications for agriculture. Concerns have been raised about the bioaccumulation of nano-Cu and their toxicity to crop plants. Here, the response of cucumber plants in hydroponic culture at early development stages to two concentrations of nano-Cu (10 and 20 mg/L) was evaluated by proton nuclear magnetic resonance spectroscopy ((1)H NMR) and gas chromatography-mass spectrometry (GC-MS) based metabolomics. Changes in mineral nutrient metabolism induced by nano-Cu were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Results showed that nano-Cu at both concentrations interferes with the uptake of a number of micro- and macro-nutrients, such as Na, P, S, Mo, Zn, and Fe. Metabolomics data revealed that nano-Cu at both levels triggered significant metabolic changes in cucumber leaves and root exudates. The root exudate metabolic changes revealed an active defense mechanism against nano-Cu stress: up-regulation of amino acids to sequester/exclude Cu/nano-Cu; down-regulation of citric acid to reduce the mobilization of Cu ions; ascorbic acid up-regulation to combat reactive oxygen species; and up-regulation of phenolic compounds to improve antioxidant system. Thus, we demonstrate that nontargeted (1)H NMR and GC-MS based metabolomics can successfully identify physiological responses induced by nanoparticles. Root exudates metabolomics revealed important detoxification mechanisms.
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Affiliation(s)
- Lijuan Zhao
- Bren School of Environmental Science and Management, University of California , Santa Barbara, California 93106-5131, United States
- University of California , Center for Environmental Implications of Nanotechnology, Santa Barbara, California 93106, United States
| | - Yuxiong Huang
- Bren School of Environmental Science and Management, University of California , Santa Barbara, California 93106-5131, United States
- University of California , Center for Environmental Implications of Nanotechnology, Santa Barbara, California 93106, United States
| | - Jerry Hu
- Materials Research Laboratory, University of California , Santa Barbara, California 93106-5050, United States
| | - Hongjun Zhou
- Neuroscience Research Institute and Molecular, Cellular and Developmental Biology, University of California Santa Barbara , Santa Barbara, California 93106, United States
| | - Adeyemi S Adeleye
- Bren School of Environmental Science and Management, University of California , Santa Barbara, California 93106-5131, United States
- University of California , Center for Environmental Implications of Nanotechnology, Santa Barbara, California 93106, United States
| | - Arturo A Keller
- Bren School of Environmental Science and Management, University of California , Santa Barbara, California 93106-5131, United States
- University of California , Center for Environmental Implications of Nanotechnology, Santa Barbara, California 93106, United States
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Di Pasquale P, Caterino M, Di Somma A, Squillace M, Rossi E, Landini P, Iebba V, Schippa S, Papa R, Selan L, Artini M, Palamara AT, Palamara A, Duilio A. Exposure of E. coli to DNA-Methylating Agents Impairs Biofilm Formation and Invasion of Eukaryotic Cells via Down Regulation of the N-Acetylneuraminate Lyase NanA. Front Microbiol 2016; 7:147. [PMID: 26904018 PMCID: PMC4749703 DOI: 10.3389/fmicb.2016.00147] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/26/2016] [Indexed: 12/26/2022] Open
Abstract
DNA methylation damage can be induced by endogenous and exogenous chemical agents, which has led every living organism to develop suitable response strategies. We investigated protein expression profiles of Escherichia coli upon exposure to the alkylating agent methyl-methane sulfonate (MMS) by differential proteomics. Quantitative proteomic data showed a massive downregulation of enzymes belonging to the glycolytic pathway and fatty acids degradation, strongly suggesting a decrease of energy production. A strong reduction in the expression of the N-acetylneuraminate lyases (NanA) involved in the sialic acid metabolism was also observed. Using a null NanA mutant and DANA, a substrate analog acting as competitive inhibitor, we demonstrated that down regulation of NanA affects biofilm formation and adhesion properties of E. coli MV1161. Exposure to alkylating agents also decreased biofilm formation and bacterial adhesion to Caco-2 eukaryotic cell line by the adherent invasive E. coli (AIEC) strain LF82. Our data showed that methylation stress impairs E. coli adhesion properties and suggest a possible role of NanA in biofilm formation and bacteria host interactions.
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Affiliation(s)
- Pamela Di Pasquale
- Department of Chemical Sciences, University of Naples "Federico II" Naples, Italy
| | - Marianna Caterino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II" Naples, Italy
| | - Angela Di Somma
- Department of Chemical Sciences, University of Naples "Federico II" Naples, Italy
| | - Marta Squillace
- Department of Chemical Sciences, University of Naples "Federico II" Naples, Italy
| | - Elio Rossi
- Department of Biosciences, University of Milan Milan, Italy
| | - Paolo Landini
- Department of Biosciences, University of Milan Milan, Italy
| | - Valerio Iebba
- Department of Public Health and Infectious Diseases, Pasteur Institute Cenci, Bolognetti Foundation, Sapienza University of Rome Rome, Italy
| | - Serena Schippa
- Department of Public Health and Infectious Diseases, Sapienza University of Rome Rome, Italy
| | - Rosanna Papa
- Department of Public Health and Infectious Diseases, Sapienza University of Rome Rome, Italy
| | - Laura Selan
- Department of Public Health and Infectious Diseases, Sapienza University of Rome Rome, Italy
| | - Marco Artini
- Department of Public Health and Infectious Diseases, Sapienza University of Rome Rome, Italy
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, Pasteur Institute Cenci, Bolognetti Foundation, Sapienza University of RomeRome, Italy; IRCCS, San Raffaele Pisana Telematic UniversityRome, Italy
| | | | - Angela Duilio
- Department of Chemical Sciences, University of Naples "Federico II" Naples, Italy
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Ishihama A, Shimada T, Yamazaki Y. Transcription profile of Escherichia coli: genomic SELEX search for regulatory targets of transcription factors. Nucleic Acids Res 2016; 44:2058-74. [PMID: 26843427 PMCID: PMC4797297 DOI: 10.1093/nar/gkw051] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/20/2016] [Indexed: 01/25/2023] Open
Abstract
Bacterial genomes are transcribed by DNA-dependent RNA polymerase (RNAP), which achieves gene selectivity through interaction with sigma factors that recognize promoters, and transcription factors (TFs) that control the activity and specificity of RNAP holoenzyme. To understand the molecular mechanisms of transcriptional regulation, the identification of regulatory targets is needed for all these factors. We then performed genomic SELEX screenings of targets under the control of each sigma factor and each TF. Here we describe the assembly of 156 SELEX patterns of a total of 116 TFs performed in the presence and absence of effector ligands. The results reveal several novel concepts: (i) each TF regulates more targets than hitherto recognized; (ii) each promoter is regulated by more TFs than hitherto recognized; and (iii) the binding sites of some TFs are located within operons and even inside open reading frames. The binding sites of a set of global regulators, including cAMP receptor protein, LeuO and Lrp, overlap with those of the silencer H-NS, suggesting that certain global regulators play an anti-silencing role. To facilitate sharing of these accumulated SELEX datasets with the research community, we compiled a database, ‘Transcription Profile of Escherichia coli’ (www.shigen.nig.ac.jp/ecoli/tec/).
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Affiliation(s)
- Akira Ishihama
- Micro-Nano Technology Research Center, Hosei University, Koganei, Tokyo, 184-8584, Japan
| | - Tomohiro Shimada
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuda, Yokohama 226-8503, Japan
| | - Yukiko Yamazaki
- National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
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Plumbridge J. Regulation of the Utilization of Amino Sugars by Escherichia coli and Bacillus subtilis: Same Genes, Different Control. J Mol Microbiol Biotechnol 2015; 25:154-67. [DOI: 10.1159/000369583] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Amino sugars are dual-purpose compounds in bacteria: they are essential components of the outer wall peptidoglycan (PG) and the outer membrane of Gram-negative bacteria and, in addition, when supplied exogenously their catabolism contributes valuable supplies of energy, carbon and nitrogen to the cell. The enzymes for both the synthesis and degradation of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) are highly conserved but during evolution have become subject to different regulatory regimes. <i>Escherichia coli</i> grows more rapidly using GlcNAc as a carbon source than with GlcN. On the other hand, <i>Bacillus subtilis,</i> but not other <i>Bacilli</i> tested, grows more efficiently on GlcN than GlcNAc. The more rapid growth on this sugar is associated with the presence of a second, GlcN-specific operon, which is unique to this species. A single locus is associated with the genes for catabolism of GlcNAc and GlcN in <i>E. coli,</i> although they enter the cell via different transporters. In <i>E. coli</i> the amino sugar transport and catabolic genes have also been requisitioned as part of the PG recycling process. Although PG recycling likely occurs in <i>B. subtilis,</i> it appears to have different characteristics.
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Abstract
ABSTRACT
Type 1 fimbriae of
E. coli
, a chaperon-usher bacterial adhesin, are synthesized by the majority of strains of the bacterium. Although frequently produced by commensal strains, the adhesin is nevertheless a virulence factor in Extraintestinal Pathogenic
E. coli
(ExPEC). The role of the adhesin in pathogenesis is best understood in Uropathogenic
E. coli
(UPEC). Host attachment and invasion by type 1 fimbriate bacteria activates inflammatory pathways, with TLR4 signaling playing a predominant role. In a mouse model of cystitis, type 1 fimbriation not only enhances UPEC adherence to the surface of superficial umbrella cells of the bladder urothelium, but is both necessary and sufficient for their invasion. Moreover the adhesin plays a role in the formation of transient intracellular bacterial communities (IBCs) within the cytoplasm of urothelial cells as part of UPEC cycles of invasion. The expression of type 1 fimbriation is controlled by phase variation at the transcriptional level, a mode of gene regulation in which bacteria switch reversibly between fimbriate and afimbriate phases. Phase variation has been widely considered to be a mechanism enabling immune evasion. Notwithstanding the apparently random nature of phase variation, switching of type 1 fimbrial expression is nevertheless controlled by a range of environmental signals that include the amino sugars sialic acid and N-acetylglucosamine (GlcNAc). Sialic acid plays a pivotal role in innate immunity, including signaling by the toll-like receptors. Here how sialic acid and GlcNAc control type 1 fimbriation is described and the potential significance of this regulatory response is discussed.
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Alteri CJ, Mobley HLT. Metabolism and Fitness of Urinary Tract Pathogens. Microbiol Spectr 2015; 3:10.1128/microbiolspec.MBP-0016-2015. [PMID: 26185076 PMCID: PMC4510461 DOI: 10.1128/microbiolspec.mbp-0016-2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Indexed: 12/12/2022] Open
Abstract
Among common infections, urinary tract infections (UTI) are the most frequently diagnosed urologic disease. The majority of UTIs are caused by uropathogenic Escherichia coli. The primary niche occupied by E. coli is the lower intestinal tract of mammals, where it resides as a beneficial component of the commensal microbiota. Although it is well-known that E. coli resides in the human intestine as a harmless commensal, specific strains or pathotypes have the potential to cause a wide spectrum of intestinal and diarrheal diseases. In contrast, extraintestinal E. coli pathotypes reside harmlessly in the human intestinal microenvironment but, upon access to sites outside of the intestine, become a major cause of human morbidity and mortality as a consequence of invasive UTI (pyelonephritis, bacteremia, or septicemia). Thus, extraintestinal pathotypes like uropathogenic E. coli (UPEC) possess an enhanced ability to cause infection outside of the intestinal tract and colonize the urinary tract, the bloodstream, or cerebrospinal fluid of human hosts. Due to the requirement for these E. coli to replicate in and colonize both the intestine and extraintestinal environments, we posit that physiology and metabolism of UPEC strains is paramount. Here we discuss that the ability to survive in the urinary tract depends as much on bacterial physiology and metabolism as it does on the well-considered virulence determinants.
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Affiliation(s)
- Christopher J. Alteri
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Harry L. T. Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
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Rossi E, Motta S, Mauri P, Landini P. Sulfate assimilation pathway intermediate phosphoadenosine 59-phosphosulfate acts as a signal molecule affecting production of curli fibres in Escherichia coli. MICROBIOLOGY-SGM 2015; 160:1832-1844. [PMID: 24934621 DOI: 10.1099/mic.0.079699-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The enterobacterium Escherichia coli can utilize a variety of molecules as sulfur sources, including cysteine, sulfate, thiosulfate and organosulfonates. An intermediate of the sulfate assimilation pathway, adenosine 59-phosphosulfate (APS), also acts as a signal molecule regulating the utilization of different sulfur sources. In this work, we show that inactivation of the cysH gene, leading to accumulation of phosphoadenosine 59-phosphosulfate (PAPS), also an intermediate of the sulfate assimilation pathway, results in increased surface adhesion and cell aggregation by activating the expression of the curli-encoding csgBAC operon. In contrast, curli production was unaffected by the inactivation of any other gene belonging to the sulfate assimilation pathway. Overexpression of the cysH gene downregulated csgBAC transcription, further suggesting a link between intracellular PAPS levels and curli gene expression. In addition to curli components, the Flu, OmpX and Slp proteins were also found in increased amounts in the outer membrane compartment of the cysH mutant; deletion of the corresponding genes suggested that these proteins also contribute to surface adhesion and cell surface properties in this strain. Our results indicate that, similar to APS, PAPS also acts as a signal molecule, albeit with a distinct mechanism and role: whilst APS regulates organosulfonate utilization, PAPS would couple availability of sulfur sources to remodulation of the cell surface, as part of a more global effect on cell physiology.
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Affiliation(s)
- Elio Rossi
- Department of Biosciences, Università degli Studi di Milano, Via Celoria, 26, 20133 Milan, Italy
| | - Sara Motta
- Institute of Biomedical Technologies, National Research Council, Via Fratelli Cervi 93, 20090 Segrate, Milan, Italy
| | - Pierluigi Mauri
- Institute of Biomedical Technologies, National Research Council, Via Fratelli Cervi 93, 20090 Segrate, Milan, Italy
| | - Paolo Landini
- Department of Biosciences, Università degli Studi di Milano, Via Celoria, 26, 20133 Milan, Italy
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Carvalho ADS, da Silva MV, Gomes FS, Paiva PMG, Malafaia CB, da Silva TD, Vaz AFDM, da Silva AG, Arruda IRDS, Napoleão TH, Carneiro-da-Cunha MDG, Correia MTDS. Purification, characterization and antibacterial potential of a lectin isolated from Apuleia leiocarpa seeds. Int J Biol Macromol 2015; 75:402-8. [PMID: 25668321 DOI: 10.1016/j.ijbiomac.2015.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 01/31/2015] [Accepted: 02/02/2015] [Indexed: 01/11/2023]
Abstract
Apuleia leiocarpa is a tree found in Caatinga that has great value in the timber industry. Lectins are carbohydrate-binding proteins with several biotechnological applications. This study shows the isolation, characterization, and antibacterial activity of A. leiocarpa seed lectin (ApulSL). The lectin was chromatographically isolated from a crude extract (in 150 mM NaCl) by using a chitin column. ApulSL adsorbed to the matrix and was eluted using 1.0 M acetic acid. Native ApulSL was characterized as a 55.8-kDa acidic protein. SDS-PAGE showed three polypeptide bands, whereas two-dimensional electrophoresis revealed four spots. The peptides detected by MALDI TOF/TOF did not show sufficient homology (<30%) with the database proteins. Circular dichroism spectroscopy suggested a disordered conformational structure, and fluorescence spectrum showed the presence of tyrosine residues in the hydrophobic core. The hemagglutinating activity of ApulSL was present even after heating to 100 °C, was Mn(2+)-dependent, and inhibited by N-acetylglucosamine, D(-)-arabinose, and azocasein. ApulSL demonstrated bacteriostatic and bactericide effects on gram-positive and gram-negative species, being more effective against three varieties of Xanthomonas campestris (MIC ranging from 11.2 to 22.5 μg/mL and MBC of 22.5 μg/mL). The results of this study reinforce the importance of biochemical prospecting of Caatinga by revealing the antibacterial potential of ApulSL.
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Affiliation(s)
- Aline de Souza Carvalho
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
| | - Márcia Vanusa da Silva
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
| | - Francis Soares Gomes
- Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, 57072-900 Maceió, Alagoas, Brazil
| | - Patrícia Maria Guedes Paiva
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
| | - Carolina Barbosa Malafaia
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
| | - Tulio Diego da Silva
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
| | - Antônio Fernando de Melo Vaz
- Centro de Saúde e Tecnologia Rural, Universidade Federal de Campina Grande, Jatobá, 58700-970 Patos, Paraíba, Brazil
| | - Alexandre Gomes da Silva
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
| | - Isabel Renata de Souza Arruda
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
| | - Thiago Henrique Napoleão
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil.
| | | | - Maria Tereza dos Santos Correia
- Departamento de Bioquímica-CCB, Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, Pernambuco, Brazil
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Liao C, Rigali S, Cassani CL, Marcellin E, Nielsen LK, Ye BC. Control of chitin and N-acetylglucosamine utilization in Saccharopolyspora erythraea. MICROBIOLOGY-SGM 2014; 160:1914-1928. [PMID: 25009237 DOI: 10.1099/mic.0.078261-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Chitin degradation and subsequent N-acetylglucosamine (GlcNAc) catabolism is thought to be a common trait of a large majority of actinomycetes. Utilization of aminosugars had been poorly investigated outside the model strain Streptomyces coelicolor A3(2), and we examined here the genetic setting of the erythromycin producer Saccharopolyspora erythraea for GlcNAc and chitin utilization, as well as the transcriptional control thereof. Sacch. erythraea efficiently utilize GlcNAc most likely via the phosphotransferase system (PTS(GlcNAc)); however, this strain is not able to grow when chitin or N,N'-diacetylchitobiose [(GlcNAc)2] is the sole nutrient source, despite a predicted extensive chitinolytic system (chi genes). The inability of Sacch. erythraea to utilize chitin and (GlcNAc)2 is probably because of the loss of genes encoding the DasABC transporter for (GlcNAc)2 import, and genes for intracellular degradation of (GlcNAc)2 by β-N-acetylglucosaminidases. Transcription analyses revealed that in Sacch. erythraea all putative chi and GlcNAc utilization genes are repressed by DasR, whereas in Strep. coelicolor DasR displayed either activating or repressing functions whether it targets genes involved in the polymer degradation or genes for GlcNAc dimer and monomer utilization, respectively. A transcriptomic analysis further showed that GlcNAc not only activates the transcription of GlcNAc catabolism genes but also activates chi gene expression, as opposed to the previously reported GlcNAc-mediated catabolite repression in Strep. coelicolor. Finally, synteny exploration revealed an identical genetic background for chitin utilization in other rare actinomycetes, which suggests that screening procedures that used only the chitin-based protocol for selective isolation of antibiotic-producing actinomycetes could have missed the isolation of many industrially promising strains.
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Affiliation(s)
- Chengheng Liao
- Laboratory of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, PR China
| | - Sébastien Rigali
- Centre for Protein Engineering, Institut de Chimie B6a, B-4000 Liège, Belgium
| | - Cuauhtemoc Licona Cassani
- Australian Institute for Bioengineering and Nanotechnology (AIBN), University of Queensland, Brisbane, Queensland 4072, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology (AIBN), University of Queensland, Brisbane, Queensland 4072, Australia
| | - Lars Keld Nielsen
- Australian Institute for Bioengineering and Nanotechnology (AIBN), University of Queensland, Brisbane, Queensland 4072, Australia
| | - Bang-Ce Ye
- Laboratory of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, PR China
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Evolved osmotolerant Escherichia coli mutants frequently exhibit defective N-acetylglucosamine catabolism and point mutations in cell shape-regulating protein MreB. Appl Environ Microbiol 2014; 80:3729-40. [PMID: 24727267 DOI: 10.1128/aem.00499-14] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Biocatalyst robustness toward stresses imposed during fermentation is important for efficient bio-based production. Osmotic stress, imposed by high osmolyte concentrations or dense populations, can significantly impact growth and productivity. In order to better understand the osmotic stress tolerance phenotype, we evolved sexual (capable of in situ DNA exchange) and asexual Escherichia coli strains under sodium chloride (NaCl) stress. All isolates had significantly improved growth under selection and could grow in up to 0.80 M (47 g/liter) NaCl, a concentration that completely inhibits the growth of the unevolved parental strains. Whole genome resequencing revealed frequent mutations in genes controlling N-acetylglucosamine catabolism (nagC, nagA), cell shape (mrdA, mreB), osmoprotectant uptake (proV), and motility (fimA). Possible epistatic interactions between nagC, nagA, fimA, and proV deletions were also detected when reconstructed as defined mutations. Biofilm formation under osmotic stress was found to be decreased in most mutant isolates, coupled with perturbations in indole secretion. Transcriptional analysis also revealed significant changes in ompACGL porin expression and increased transcription of sulfonate uptake systems in the evolved mutants. These findings expand our current knowledge of the osmotic stress phenotype and will be useful for the rational engineering of osmotic tolerance into industrial strains in the future.
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Abstract
Beyond fuelling cellular activities with building blocks and energy, metabolism also integrates environmental conditions into intracellular signals. The underlying regulatory network is complex and multifaceted: it ranges from slow interactions, such as changing gene expression, to rapid ones, such as the modulation of protein activity via post-translational modification or the allosteric binding of small molecules. In this Review, we outline the coordination of common metabolic tasks, including nutrient uptake, central metabolism, the generation of energy, the supply of amino acids and protein synthesis. Increasingly, a set of key metabolites is recognized to control individual regulatory circuits, which carry out specific functions of information input and regulatory output. Such a modular view of microbial metabolism facilitates an intuitive understanding of the molecular mechanisms that underlie cellular decision making.
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Abstract
Bacterial genomes are remarkably stable from one generation to the next but are plastic on an evolutionary time scale, substantially shaped by horizontal gene transfer, genome rearrangement, and the activities of mobile DNA elements. This implies the existence of a delicate balance between the maintenance of genome stability and the tolerance of genome instability. In this review, we describe the specialized genetic elements and the endogenous processes that contribute to genome instability. We then discuss the consequences of genome instability at the physiological level, where cells have harnessed instability to mediate phase and antigenic variation, and at the evolutionary level, where horizontal gene transfer has played an important role. Indeed, this ability to share DNA sequences has played a major part in the evolution of life on Earth. The evolutionary plasticity of bacterial genomes, coupled with the vast numbers of bacteria on the planet, substantially limits our ability to control disease.
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39
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Yu ZT, Chen C, Newburg DS. Utilization of major fucosylated and sialylated human milk oligosaccharides by isolated human gut microbes. Glycobiology 2013; 23:1281-92. [PMID: 24013960 PMCID: PMC3796377 DOI: 10.1093/glycob/cwt065] [Citation(s) in RCA: 255] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 08/14/2013] [Accepted: 08/14/2013] [Indexed: 12/31/2022] Open
Abstract
Human milk oligosaccharides (HMOS) are not digested in the proximal intestine. In distal intestine, HMOS collectively modify the microbiota, but the response of individual bacteria to individual components of the HMOS is not well defined. Here, each of 25 major isolates of the human intestinal microbiota was fed individual major fucosylated and sialylated HMOS in anaerobic culture. This allowed for an assessment of the influence of specific HMOS on the growth and metabolic products of individual microbiota bacteria. Most Bifidobacteria spp. and Bacteroides spp. grew, induced α-L-fucosidase activity, and produced abundant lactate or short-chain fatty acids (SCFAs) when fed 2'-fucosyllactose (2'-FL), 3-FL, and lactodifucotetraose (LDFT). Lactobacillus delbrueckii ATCC7830, Enterococcus faecalis ATCC19433, and Streptococcus thermophilus ATCC19258 exhibited slight growth, pH reduction, and lactate production when supplemented with 2'-FL or 3-FL, but not LDFT. Supplementation with 3'-sialyllactose (3'-SL) and 6'-SL promoted moderate growth of Bifidobacterium longum JCM7007, 7009, 7010, 7011, 1272, 11347, ATCC15708, Bacteroides vulgatus ATCC8482, and B. thetaiotaomicron ATCC29148; accordingly, these bacteria exhibited greater neuraminidase activity and produced copious lactate, SCFA, or both. Lactobacillus delbrueckii ATCC7830 also consumed 6'-SL. In contrast, Clostridium spp., L. rhamnosus ATCC53103, E. faecalis ATCC29200, Staphylococcus spp., Enterobacter spp., and Escherichia coli K12 did not consume milk oligosaccharides nor produce appreciable acidic fermentation products. Specific Bifidobacteria and Bacteroides differentially digest specific individual HMOS, with the major fucosylated milk oligosaccharides most strongly stimulating key species of mutualist symbionts. This suggests strategies for treating dysbiosis of the microbiota and associated inflammatory disorders.
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Affiliation(s)
| | | | - David S Newburg
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
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40
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Abstract
The phase variation (reversible on-off switching) of the type 1 fimbrial adhesin of Escherichia coli involves a DNA inversion catalyzed by FimB (switching in either direction) or FimE (on-to-off switching). Here, we demonstrate that RfaH activates expression of a FimB-LacZ protein fusion while having a modest inhibitory effect on a comparable fimB-lacZ operon construct and on a FimE-LacZ protein fusion, indicating that RfaH selectively controls fimB expression at the posttranscriptional level. Further work demonstrates that loss of RfaH enables small RNA (sRNA) MicA inhibition of fimB expression even in the absence of exogenous inducing stress. This effect is explained by induction of σ(E), and hence MicA, in the absence of RfaH. Additional work confirms that the procaine-dependent induction of micA requires OmpR, as reported previously (A. Coornaert et al., Mol. Microbiol. 76:467-479, 2010, doi:10.1111/j.1365-2958.2010.07115.x), but also demonstrates that RfaH inhibition of fimB transcription is enhanced by procaine independently of OmpR. While the effect of procaine on fimB transcription is shown to be independent of RcsB, it was found to require SlyA, another known regulator of fimB transcription. These results demonstrate a complex role for RfaH as a regulator of fimB expression.
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41
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Control of the Escherichia coli sialoregulon by transcriptional repressor NanR. J Bacteriol 2013; 195:4689-701. [PMID: 23935044 DOI: 10.1128/jb.00692-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
NanR, one of >8,500 GntR superfamily helix-turn-helix transcriptional regulators, controls expression of the genes required for catabolism of sialic acids in Escherichia coli. It is predicted to do the same in related bacteria harboring orthologs of nanR. The sialic acids are a family of over 40 naturally occurring nine-carbon keto-sugar acids found mainly in the animal lineage, which includes starfish to humans in the deuterostome lineage. Sialic acids function in development, immunity, protein localization and stability, and homeostasis. They also serve as microbial carbon and nitrogen sources and ligands for cell recognition during host colonization. The importance of microbial sialic acid metabolism for host-microbe interactions has made it a target for therapeutic development. Exploiting this target depends on understanding sialometabolic pathways in a wide range of evolutionarily distinct bacteria. Here, we show by transcriptome, genetic, and biochemical analyses that the most common sialic acid, N-acetylneuraminate, induces the nanATEK-yhcH, yjhATS (nanCMS), and yjhBC operons by directly inactivating NanR, converting the predominantly dimeric form of the repressor to an inactive monomer of approximately 30-kDa. Additionally, other results identify critical amino acid residues and nucleotides in the regulator and operator, respectively. The combined results better define how sialic acids, acting through NanR, affect the metabolic flux of an important group of host-derived metabolites. Thus, E. coli serves as a valuable model for understanding sialocatabolic pathways in bacteria.
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Guevara CP, Luiz WB, Sierra A, Cruz C, Qadri F, Kaushik RS, Ferreira LCS, Gómez-Duarte OG. Enterotoxigenic Escherichia coli CS21 pilus contributes to adhesion to intestinal cells and to pathogenesis under in vivo conditions. MICROBIOLOGY-SGM 2013; 159:1725-1735. [PMID: 23760820 DOI: 10.1099/mic.0.065532-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Colonization surface antigens (CSs) represent key virulence-associated factors of enterotoxigenic Escherichia coli (ETEC) strains. They are required for gut colonization, the first step of the diarrhoeal disease process induced by these bacteria. One of the most prevalent CSs is CS21, or longus, a type IV pili associated with bacterial self-aggregation, protection against environmental stresses, biofilm formation and adherence to epithelial cell lines. The objectives of this study were to assess the role of CS21 in adherence to primary intestinal epithelial cells and to determine if CS21 contributes to the pathogenesis of ETEC infection in vivo. We evaluated adherence of a CS21-expressing wild-type ETEC strain and an isogenic CS21-mutant strain to pig-derived intestinal cell lines. To determine the role of CS21 in pathogenesis we used the above ETEC strains in a neonatal mice challenge infection model to assess mortality. Quantitative adherence assays confirmed that ETEC adheres to primary intestinal epithelial cells lines in a CS21-dependent manner. In addition, the CS21-mediated ETEC adherence to cells was specific as purified LngA protein, the CS21 major subunit, competed for binding with the CS21-expressing ETEC while specific anti-LngA antibodies blocked adhesion to intestinal cells. Neonatal DBA/2 mice died after intra-stomach administration of CS21-expressing strains while lack of CS21 expression drastically reduced the virulence of the wild-type ETEC strain in this animal model. Collectively these results further support the role of CS21 during ETEC infection and add new evidence on its in vivo relevance in pathogenesis.
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Affiliation(s)
- C P Guevara
- Department of Pediatrics, University of Iowa College of Medicine, Iowa City, IA, USA
| | - W B Luiz
- Department of Microbiology, Biomedical Sciences Institute, University of São Paulo, 05508-000 São Paulo, Brazil
| | - A Sierra
- Internal Medicine, University of Iowa College of Medicine, Iowa City, IA, USA
| | - C Cruz
- Department of Pediatrics, University of Iowa College of Medicine, Iowa City, IA, USA
| | - F Qadri
- International Centre for Diarrheal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh
| | - R S Kaushik
- Departments of Biology and Microbiology, and Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, USA
| | - L C S Ferreira
- Department of Microbiology, Biomedical Sciences Institute, University of São Paulo, 05508-000 São Paulo, Brazil
| | - O G Gómez-Duarte
- Department of Pediatrics, University of Iowa College of Medicine, Iowa City, IA, USA
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43
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Abstract
Transcriptional regulation is at the heart of biological functions such as adaptation to a changing environment or to new carbon sources. One of the mechanisms which has been found to modulate transcription, either positively (activation) or negatively (repression), involves the formation of DNA loops. A DNA loop occurs when a protein or a complex of proteins simultaneously binds to two different sites on DNA with looping out of the intervening DNA. This simple mechanism is central to the regulation of several operons in the genome of the bacterium Escherichia coli, like the lac operon, one of the paradigms of genetic regulation. The aim of this review is to gather and discuss concepts and ideas from experimental biology and theoretical physics concerning DNA looping in genetic regulation. We first describe experimental techniques designed to show the formation of a DNA loop. We then present the benefits that can or could be derived from a mechanism involving DNA looping. Some of these are already experimentally proven, but others are theoretical predictions and merit experimental investigation. Then, we try to identify other genetic systems that could be regulated by a DNA looping mechanism in the genome of Escherichia coli. We found many operons that, according to our set of criteria, have a good chance to be regulated with a DNA loop. Finally, we discuss the proposition recently made by both biologists and physicists that this mechanism could also act at the genomic scale and play a crucial role in the spatial organization of genomes.
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Lluch-Senar M, Luong K, Lloréns-Rico V, Delgado J, Fang G, Spittle K, Clark TA, Schadt E, Turner SW, Korlach J, Serrano L. Comprehensive methylome characterization of Mycoplasma genitalium and Mycoplasma pneumoniae at single-base resolution. PLoS Genet 2013; 9:e1003191. [PMID: 23300489 PMCID: PMC3536716 DOI: 10.1371/journal.pgen.1003191] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 11/08/2012] [Indexed: 11/18/2022] Open
Abstract
In the bacterial world, methylation is most commonly associated with restriction-modification systems that provide a defense mechanism against invading foreign genomes. In addition, it is known that methylation plays functionally important roles, including timing of DNA replication, chromosome partitioning, DNA repair, and regulation of gene expression. However, full DNA methylome analyses are scarce due to a lack of a simple methodology for rapid and sensitive detection of common epigenetic marks (ie N6-methyladenine (6 mA) and N4-methylcytosine (4 mC)), in these organisms. Here, we use Single-Molecule Real-Time (SMRT) sequencing to determine the methylomes of two related human pathogen species, Mycoplasma genitalium G-37 and Mycoplasma pneumoniae M129, with single-base resolution. Our analysis identified two new methylation motifs not previously described in bacteria: a widespread 6 mA methylation motif common to both bacteria (5′-CTAT-3′), as well as a more complex Type I m6A sequence motif in M. pneumoniae (5′-GAN7TAY-3′/3′-CTN7ATR-5′). We identify the methyltransferase responsible for the common motif and suggest the one involved in M. pneumoniae only. Analysis of the distribution of methylation sites across the genome of M. pneumoniae suggests a potential role for methylation in regulating the cell cycle, as well as in regulation of gene expression. To our knowledge, this is one of the first direct methylome profiling studies with single-base resolution from a bacterial organism. DNA methylation in bacteria plays important roles in cell division, DNA repair, regulation of gene expression, and pathogenesis. Here, we use a novel sequencing technique, Single-Molecule Real-Time (SMRT) sequencing, to determine the methylomes of two related human pathogen species, Mycoplasma genitalium G-37 and Mycoplasma pneumoniae M129. Our analysis identified two novel methylation motifs, one of them present uniquely in M. pneumoniae and the other common to both bacteria. We also identify the methyltransferase responsible for the common methylation motif and suggest the one associated with the M. pneumoniae unique motif. Functional analysis of the data suggests a potential role for methylation in regulating the cell cycle of M. pneumoniae, as well as in regulation of gene expression. To our knowledge, this is one of the first genome-wide approaches to study the biological role of methylation in a bacterial organism.
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Affiliation(s)
- Maria Lluch-Senar
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), Barcelona, Spain.
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45
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Abstract
N-acetylglucosamine (GlcNAc) has long been known to play important roles in cell surface structure. Recent studies are now revealing new functions for GlcNAc in cell signaling. Exposure to GlcNAc regulates virulence functions in the human fungal pathogen Candida albicans and in pathogenic bacteria. These signaling pathways sense exogenous GlcNAc and are distinct from the O-GlcNAc signaling pathways in mammalian cells in which increased levels of intracellular GlcNAc synthesis leads to post-translational modification of proteins by attachment of O-GlcNAc. The novel roles of GlcNAc in cell signaling will be the subject of this mini-review.
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46
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Salcedo J, Barbera R, Matencio E, Alegría A, Lagarda MJ. Gangliosides and sialic acid effects upon newborn pathogenic bacteria adhesion: an in vitro study. Food Chem 2012; 136:726-34. [PMID: 23122120 DOI: 10.1016/j.foodchem.2012.08.078] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/27/2012] [Accepted: 08/30/2012] [Indexed: 12/13/2022]
Abstract
The effect of the main gangliosides (GM(1), GM(3), GD(3)) and free sialic acid (Neu5Ac) upon the adhesion of pathogenic bacteria implicated in infant diarrhoea is assessed in vitro using the Caco-2 cell line. Concentrations of the bioactive compounds found in the bioaccessible (soluble) fraction of infant formula and human milk are employed. Bacterial adhesion behaviour included enterotoxigenic Escherichia coli (ETEC), enteropathogenic E.coli (EPEC), Listeria monocytogenes, Salmonella entericaserovartyphi, Shigella sonnei, Campylobacter jejuni and Helicobacter pylori. Three different approaches were assayed: pre-incubation of bacteria and compounds before addition to cells (competition); pre-incubation of the cells with compounds (exclusion); and pre-incubation of cells with bacteria (displacement). Furthermore, the spatial localization of the most abundant gangliosides, GM(3) and GD(3), in Caco-2 cells has been determined using confocal microscopy. Results show that GM(3), GD(3), GM(1) and Neu5Ac at the assayed concentrations are able to interfere with the adhesion of several pathogenic bacteria involved in neonatal diseases-the greatest effect corresponding to Neu5Ac, followed by GD(3), GM(1) and GM(3). Gangliosides GM(3) and GD(3) are located in the apical and basolateral membranes of the Caco-2 cells.
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Affiliation(s)
- J Salcedo
- Department of Nutrition and Food Chemistry, Faculty of Pharmacy, University of Valencia, Avenida Vicente Andrés Estellés s/n, 46100-Burjassot, Valencia, Spain.
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Decreased expression of type 1 fimbriae by a pst mutant of uropathogenic Escherichia coli reduces urinary tract infection. Infect Immun 2012; 80:2802-15. [PMID: 22665376 DOI: 10.1128/iai.00162-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pstSCAB-phoU operon encodes the phosphate-specific transport system (Pst). Loss of Pst constitutively activates the Pho regulon and decreases bacterial virulence. However, specific mechanisms underlying decreased bacterial virulence through inactivation of Pst are poorly understood. In uropathogenic Escherichia coli (UPEC) strain CFT073, inactivation of pst decreased urinary tract colonization in CBA/J mice. The pst mutant was deficient in production of type 1 fimbriae and showed decreased expression of the fimA structural gene which correlated with differential expression of the fimB, fimE, ipuA, and ipbA genes, encoding recombinases, mediating inversion of the fim promoter. The role of fim downregulation in attenuation of the pst mutant was confirmed using a fim phase-locked-on derivative, which demonstrated a significant gain in virulence. In addition, the pst mutant was less able to invade human bladder epithelial cells. Since type 1 fimbriae contribute to UPEC virulence by promoting colonization and invasion of bladder cells, the reduced bladder colonization by the pst mutant is predominantly attributed to downregulation of these fimbriae. Elucidation of mechanisms mediating the control of type 1 fimbriae through activation of the Pho regulon in UPEC may open new avenues for therapeutics or prophylactics against urinary tract infections.
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48
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Weiss GA, Hennet T. The role of milk sialyllactose in intestinal bacterial colonization. Adv Nutr 2012; 3:483S-8S. [PMID: 22585928 PMCID: PMC3649486 DOI: 10.3945/an.111.001651] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Milk oligosaccharides influence the composition of intestinal microbiota and thereby mucosal inflammation. Some of the major milk oligosaccharides are α2,3-sialyllactose (3SL) and α2,6-sialyllactose, which are mainly produced by the sialyltransferases ST3GAL4 and ST6GAL1, respectively. Recently, we showed that mice fed milk deficient in 3SL were more resistant to dextran sulfate sodium-induced colitis. By contrast, the exposure to milk containing or deficient in 3SL had no impact on the development of mucosal leukocyte populations. Milk 3SL mainly affected the colonization of the intestine by clostridial cluster IV bacteria.
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Affiliation(s)
- G. Adrienne Weiss
- Institute of Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland; and,Clinical Chemistry and Biochemistry, University Children’s Hospital Zurich, Switzerland
| | - Thierry Hennet
- Institute of Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland; and,To whom correspondence should be addressed. E-mail:
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49
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Konopka JB. N-acetylglucosamine (GlcNAc) functions in cell signaling. SCIENTIFICA 2012; 2012:489208. [PMID: 23350039 PMCID: PMC3551598 DOI: 10.6064/2012/489208] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 10/23/2012] [Indexed: 05/21/2023]
Abstract
The amino sugar N-acetylglucosamine (GlcNAc) is well known for the important structural roles that it plays at the cell surface. It is a key component of bacterial cell wall peptidoglycan, fungal cell wall chitin, and the extracellular matrix of animal cells. Interestingly, recent studies have also identified new roles for GlcNAc in cell signaling. For example, GlcNAc stimulates the human fungal pathogen Candida albicans to undergo changes in morphogenesis and expression of virulence genes. Pathogenic E. coli respond to GlcNAc by altering the expression of fimbriae and CURLI fibers that promote biofilm formation and GlcNAc stimulates soil bacteria to undergo changes in morphogenesis and production of antibiotics. Studies with animal cells have revealed that GlcNAc influences cell signaling through the post-translational modification of proteins by glycosylation. O-linked attachment of GlcNAc to Ser and Thr residues regulates a variety of intracellular proteins, including transcription factors such as NFκB, c-myc and p53. In addition, the specificity of Notch family receptors for different ligands is altered by GlcNAc attachment to fucose residues in the extracellular domain. GlcNAc also impacts signal transduction by altering the degree of branching of N-linked glycans, which influences cell surface signaling proteins. These emerging roles of GlcNAc as an activator and mediator of cellular signaling in fungi, animals, and bacteria will be the focus of this review.
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Affiliation(s)
- James B. Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794-5222, USA
- *James B. Konopka:
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50
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Abstract
Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections in women, causing significant morbidity and mortality in this population. Adherence to host epithelial cells is a pivotal step in the pathogenesis of UPEC. One of the most important virulence factors involved in mediating this attachment is the type 1 pilus (type 1 fimbria) encoded by a set of fim genes arranged in an operon. The expression of type 1 pili is controlled by a phenomenon known as phase variation, which reversibly switches between the expression of type 1 pili (Phase-ON) and loss of expression (Phase-OFF). Phase-ON cells have the promoter for the fimA structural gene on an invertible DNA element called fimS, which lines up to allow transcription, whereas transcription of the structural gene is silenced in Phase-OFF cells. The orientation of the fimS invertible element is controlled by two site-specific recombinases, FimB and FimE. Environmental conditions cause transcriptional and post-transcriptional changes in UPEC cells that affect the level of regulatory proteins, which in turn play vital roles in modulating this phase switching ability. The role of fim gene regulation in UPEC pathogenesis will be discussed.
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