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1.
Cell ; 172(3): 632-632.e2, 2018 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-29373833

RESUMO

O-glycosylation is one of the most abundant and diverse types of post-translational modifications of proteins. O-glycans modulate the structure, stability, and function of proteins and serve generalized as well as highly specific roles in most biological processes. This ShapShot presents types of O-glycans found in different organisms and their principle biosynthetic pathways. To view this SnapShot, open or download the PDF.


Assuntos
Evolução Molecular , Processamento de Proteína Pós-Traducional , Animais , Bactérias/genética , Bactérias/metabolismo , Drosophila/genética , Drosophila/metabolismo , Fungos/genética , Fungos/metabolismo , Glicosilação , Nematoides/genética , Nematoides/metabolismo , Plantas/metabolismo , Vertebrados/genética , Vertebrados/metabolismo
2.
Chembiochem ; : e202400037, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38688858

RESUMO

Our gut microbiota directly influences human physiology in health and disease. The myriad of surface glycoconjugates in both the bacterial cell envelope and our gut cells dominate the microbiota-host interface and play a critical role in host response and microbiota homeostasis. Among these, peptidoglycan is the basic glycan polymer offering the cell rigidity and a basis on which many other glycoconjugates are anchored. To directly study peptidoglycan in gut commensals and obtain the molecular insight required to understand their functional activities we need effective techniques like chemical probes to label peptidoglycan in live bacteria. Here we report a chemically guided approach to study peptidoglycan in a key mucin-degrading gut microbiota member of the Verrucomicrobia phylum, Akkermansia muciniphila. Two novel non-toxic tetrazine click-compatible peptidoglycan probes with either a cyclopropene or isonitrile handle allowed for the detection and imaging of peptidoglycan synthesis in this intestinal species.

3.
Glycobiology ; 32(8): 712-719, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35452117

RESUMO

Akkermansia muciniphila is an intestinal symbiont known to improve the gut barrier function in mice and humans. Various cell envelope components have been identified to play a critical role in the immune signaling of A. muciniphila, but the chemical composition and role of peptidoglycan (PG) remained elusive. Here, we isolated PG fragments from A. muciniphila MucT (ATCC BAA-835), analyzed their composition and evaluated their immune signaling capacity. Structurally, the PG of A. muciniphila was found to be noteworthy due of the presence of some nonacetylated glucosamine residues, which presumably stems from deacetylation of N-acetylglucosamine. Some of the N-acetylmuramic acid (MurNAc) subunits were O-acetylated. The immunological assays revealed that muropeptides released from the A. muciniphila PG could both activate the intracellular NOD1 and NOD2 receptors to a comparable extent as muropeptides from Escherichia coli BW25113. These data challenge the hypothesis that non-N-acetylattion of PG can be used as a NOD-1 evasion mechanism. Our results provide new insights into the diversity of cell envelope structures of key gut microbiota members and their role in steering host-microbiome interactions.


Assuntos
Microbioma Gastrointestinal , Peptidoglicano , Akkermansia , Animais , Humanos , Camundongos , Verrucomicrobia/fisiologia
4.
J Hum Nutr Diet ; 35(2): 280-299, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35040200

RESUMO

Human milk oligosaccharides (HMOs) have been researched by scientists for over 100 years, driven by the substantial evidence for the nutritional and health benefits of mother's milk. Yet research has truly bloomed during the last decade, thanks to progress in biotechnology, which has allowed the production of large amounts of bona fide HMOs. The availability of HMOs has been particularly crucial for the renewed interest in HMO research because of the low abundance or even absence of HMOs in farmed animal milk. This interest is reflected in the increasing number of original research publications and reviews on HMOs. Here, we provide an overview and critical discussion on structure-function relations of HMOs that highlight why they are such interesting and important components of human milk. Clinical observations in breastfed infants backed by basic research from animal models provide guidance as to what physiological roles for HMOs are to be expected. From an evidence-based nutrition viewpoint, we discuss the current data supporting the clinical relevance of specific HMOs based on randomised placebo-controlled clinical intervention trials in formula-fed infants.


Assuntos
Leite Humano , Oligossacarídeos , Animais , Biologia , Aleitamento Materno , Feminino , Humanos , Lactente , Estado Nutricional
5.
Appl Microbiol Biotechnol ; 105(3): 1123-1131, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33417041

RESUMO

Many studies have established the functional properties of Lacticaseibacillus rhamnosus GG, previously known as Lactobacillus rhamnosus GG, marketed worldwide as a probiotic. The extraordinary capacity of L. rhamnosus GG to bind to human mucus and influence the immune system especially stand out. Earlier, we have shown the key role of its SpaCBA sortase-dependent pili encoded by the spaCBA-srtC1 gene cluster herein. These heterotrimeric pili consist of a shaft pilin SpaA, a basal pilin SpaB, and tip pilin SpaC that contains a mucus-binding domain. Here, we set out to characterize a food-grade non-GMO mutant of L. rhamnosus GG, strain PA11, which secretes its pilins, rather than coupling them to the cell surface, due to a defect in the housekeeping sortase A. The sortase-negative strain PA11 was extensively characterized using functional genomics and biochemical approaches and found to secrete the SpaCBA pili into the supernatant. Given the functional importance and uniqueness of the mucus-binding pili of L. rhamnosus GG, strain PA11 offers novel opportunities towards the characterization and further therapeutic application of SpaCBA pili and their low-cost, large-scale production. KEY POINTS: •Creation of pilus-secreting mutant (PA11) of the key probiotic LGG. •Strain PA11 is defective in a functional housekeeping sortase SrtA. •Strain PA11 opens novel biotherapeutic application avenues. Graphical abstract.


Assuntos
Lacticaseibacillus rhamnosus , Probióticos , Proteínas de Bactérias/genética , Proteínas de Fímbrias , Fímbrias Bacterianas/genética , Humanos , Lacticaseibacillus rhamnosus/genética , Muco
6.
Appl Environ Microbiol ; 82(19): 5756-62, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27422834

RESUMO

UNLABELLED: Vancomycin-resistant enterococci (VRE) have become a major nosocomial threat. Enterococcus faecium is of special concern, as it can easily acquire new antibiotic resistances and is an excellent colonizer of the human intestinal tract. Several clinical studies have explored the potential use of beneficial bacteria to weed out opportunistic pathogens. Specifically, the widely studied Lactobacillus rhamnosus strain GG has been applied successfully in the context of VRE infections. Here, we provide new insight into the molecular mechanism underlying the effects of this model probiotic on VRE decolonization. Both clinical VRE isolates and L. rhamnosus GG express pili on their cell walls, which are the key modulators of their highly efficient colonization of the intestinal mucosa. We found that one of the VRE pilus clusters shares considerable sequence similarity with the SpaCBA-SrtC1 pilus cluster of L. rhamnosus GG. Remarkable immunological and functional similarities were discovered between the mucus-binding pili of L. rhamnosus GG and those of the clinical E. faecium strain E1165, which was characterized at the genome level. Moreover, E. faecium strain E1165 bound efficiently to mucus, which may be prevented by the presence of the mucus-binding SpaC protein or antibodies against L. rhamnosus GG or SpaC. These results present experimental support for a novel probiotic mechanism, in which the mucus-binding pili of L. rhamnosus GG prevent the binding of a potential pathogen to the host. Hence, we provide a molecular basis for the further exploitation of L. rhamnosus GG and its pilins for prophylaxis and treatment of VRE infections. IMPORTANCE: Concern about vancomycin-resistant Enterococcus faecium causing nosocomial infections is rising globally. The arsenal of antibiotic strategies to treat these infections is nearly exhausted, and hence, new treatment strategies are urgently needed. Here, we provide molecular evidence to underpin reports of the successful clinical application of Lactobacillus rhamnosus GG in VRE decolonization strategies. Our results provide support for a new molecular mechanism, in which probiotics can perform competitive exclusion and possibly immune interaction. Moreover, we spur further exploration of the potential of intact L. rhamnosus GG and purified SpaC pilin as prophylactic and curative agents of the VRE carrier state.


Assuntos
Enterococcus faecium/fisiologia , Fímbrias Bacterianas/metabolismo , Lacticaseibacillus rhamnosus/fisiologia , Interações Microbianas , Muco/microbiologia , Probióticos/metabolismo , Humanos
7.
BMC Genomics ; 15: 349, 2014 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-24885406

RESUMO

BACKGROUND: Bacterial interactions with the environment- and/or host largely depend on the bacterial glycome. The specificities of a bacterial glycome are largely determined by glycosyltransferases (GTs), the enzymes involved in transferring sugar moieties from an activated donor to a specific substrate. Of these GTs their coding regions, but mainly also their substrate specificity are still largely unannotated as most sequence-based annotation flows suffer from the lack of characterized sequence motifs that can aid in the prediction of the substrate specificity. RESULTS: In this work, we developed an analysis flow that uses sequence-based strategies to predict novel GTs, but also exploits a network-based approach to infer the putative substrate classes of these predicted GTs. Our analysis flow was benchmarked with the well-documented GT-repertoire of Campylobacter jejuni NCTC 11168 and applied to the probiotic model Lactobacillus rhamnosus GG to expand our insights in the glycosylation potential of this bacterium. In L. rhamnosus GG we could predict 48 GTs of which eight were not previously reported. For at least 20 of these GTs a substrate relation was inferred. CONCLUSIONS: We confirmed through experimental validation our prediction of WelI acting upstream of WelE in the biosynthesis of exopolysaccharides. We further hypothesize to have identified in L. rhamnosus GG the yet undiscovered genes involved in the biosynthesis of glucose-rich glycans and novel GTs involved in the glycosylation of proteins. Interestingly, we also predict GTs with well-known functions in peptidoglycan synthesis to also play a role in protein glycosylation.


Assuntos
Proteínas de Bactérias/genética , Campylobacter jejuni/enzimologia , Glicosiltransferases/genética , Lacticaseibacillus rhamnosus/enzimologia , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Campylobacter jejuni/metabolismo , Redes Reguladoras de Genes/genética , Glicosilação , Glicosiltransferases/química , Glicosiltransferases/metabolismo , Lacticaseibacillus rhamnosus/metabolismo , Cadeias de Markov , Especificidade por Substrato
8.
Nat Commun ; 15(1): 4582, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38811534

RESUMO

The intestinal anaerobic bacterium Akkermansia muciniphila is specialized in the degradation of mucins, which are heavily O-glycosylated proteins that constitute the major components of the mucus lining the intestine. Despite that adhesion to mucins is considered critical for the persistence of A. muciniphila in the human intestinal tract, our knowledge of how this intestinal symbiont recognizes and binds to mucins is still limited. Here, we first show that the mucin-binding properties of A. muciniphila are independent of environmental oxygen concentrations and not abolished by pasteurization. We then dissected the mucin-binding properties of pasteurized A. muciniphila by use of a recently developed cell-based mucin array that enables display of the tandem repeats of human mucins with distinct O-glycan patterns and structures. We found that A. muciniphila recognizes the unsialylated LacNAc (Galß1-4GlcNAcß1-R) disaccharide selectively on core2 and core3 O-glycans. This disaccharide epitope is abundantly found on human colonic mucins capped by sialic acids, and we demonstrated that endogenous A. muciniphila neuraminidase activity can uncover the epitope and promote binding. In summary, our study provides insights into the mucin-binding properties important for colonization of a key mucin-foraging bacterium.


Assuntos
Akkermansia , Mucinas , Polissacarídeos , Akkermansia/metabolismo , Humanos , Mucinas/metabolismo , Polissacarídeos/metabolismo , Neuraminidase/metabolismo , Ligação Proteica , Glicosilação , Dissacarídeos/metabolismo , Verrucomicrobia/metabolismo , Epitopos/metabolismo , Aderência Bacteriana
9.
Artigo em Inglês | MEDLINE | ID: mdl-37023733

RESUMO

Human milk contains all nutritive and bioactive compounds to give infants the best possible start in life. Human milk bioactives cover a broad range of components, including immune cells, antimicrobial proteins, microbes, and human milk oligosaccharides (HMOs). Over the last decade, HMOs have gained special attention as their industrial production has allowed the study of their structure-function relation in reductionist experimental setups. This has shed light on how HMOs steer microbiome and immune system development in early life but also how HMOs affect infant health (e.g., antibiotic use, respiratory tract infections). We are on the verge of a new era where we can examine human milk as a complex biological system. This allows not only study of the mode of action and causality of individual human milk components but also investigation of synergistic effects that might exist between different bioactives. This new wave in human milk research is largely fueled by significant advances in analytical tools in the field of systems biology and network analysis. It will be exciting to explore how human milk composition is affected by different factors, how different human milk compounds work together, and how this influences healthy infant development.


Assuntos
Microbiota , Leite Humano , Oligossacarídeos , Criança , Feminino , Humanos , Lactente , Antibacterianos/análise , Antibacterianos/metabolismo , Aleitamento Materno , Saúde da Criança , Leite Humano/química , Oligossacarídeos/análise
10.
Appl Environ Microbiol ; 78(1): 185-93, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22020518

RESUMO

Lactobacillus rhamnosus GG, a probiotic with good survival capacity in the human gut, has well-documented adhesion properties and health effects. Recently, spaCBA-encoded pili that bind to human intestinal mucus were identified on its cell surface. Here, we report on the phenotypic analysis of a spaCBA pilus knockout mutant in comparison with the wild type and other adhesin mutants. The SpaCBA pilus of L. rhamnosus GG showed to be key for efficient adherence to the Caco-2 intestinal epithelial cell (IEC) line and biofilm formation. Moreover, the spaCBA mutant induces an elevated level of interleukin-8 (IL-8) mRNA in Caco-2 cells compared to the wild type, possibly involving an interaction of lipoteichoic acid with Toll-like receptor 2. In contrast, an L. rhamnosus GG mutant without exopolysaccharides but with an increased exposure of pili leads to the reduced expression of IL-8. Using Transwells to partition bacteria from Caco-2 cells, IL-8 induction is blocked completely regardless of whether wild-type or mutant L. rhamnosus GG cells are used. Taken together, our data suggest that L. rhamnosus GG SpaCBA pili, while promoting strong adhesive interactions with IECs, have a functional role in balancing IL-8 mRNA expression induced by surface molecules such as lipoteichoic acid.


Assuntos
Aderência Bacteriana , Fímbrias Bacterianas/fisiologia , Mucosa Intestinal/microbiologia , Lacticaseibacillus rhamnosus/fisiologia , Biofilmes , Células CACO-2 , Citocinas/metabolismo , Fímbrias Bacterianas/genética , Fímbrias Bacterianas/imunologia , Técnicas de Inativação de Genes , Humanos , Interleucina-8/metabolismo , Mucosa Intestinal/citologia , Mucosa Intestinal/imunologia , Lacticaseibacillus rhamnosus/citologia , Lacticaseibacillus rhamnosus/imunologia , Fenótipo , Probióticos
11.
Microb Cell Fact ; 11: 15, 2012 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-22297095

RESUMO

BACKGROUND: Although the occurrence, biosynthesis and possible functions of glycoproteins are increasingly documented for pathogens, glycoproteins are not yet widely described in probiotic bacteria. Nevertheless, knowledge of protein glycosylation holds important potential for better understanding specific glycan-mediated interactions of probiotics and for glycoengineering in food-grade microbes. RESULTS: Here, we provide evidence that the major secreted protein Msp1/p75 of the probiotic Lactobacillus rhamnosus GG is glycosylated. Msp1 was shown to stain positive with periodic-acid Schiff staining, to be susceptible to chemical deglycosylation, and to bind with the mannose-specific Concanavalin A (ConA) lectin. Recombinant expression in Escherichia coli resulted in a significant reduction in molecular mass, loss of ConA reactivity and increased sensitivity towards pronase E and proteinase K. Mass spectrometry showed that Msp1 is O-glycosylated and identified a glycopeptide TVETPSSA (amino acids 101-108) bearing hexoses presumably linked to the serine residues. Interestingly, these serine residues are not present in the homologous protein of several Lactobacillus casei strains tested, which also did not bind to ConA. The role of the glycan substitutions in known functions of Msp1 was also investigated. Glycosylation did not seem to impact significantly on the peptidoglycan hydrolase activity of Msp1. In addition, the glycan chain appeared not to be required for the activation of Akt signaling in intestinal epithelial cells by Msp1. On the other hand, examination of different cell extracts showed that Msp1 is a glycosylated protein in the supernatant, but not in the cell wall and cytosol fraction, suggesting a link between glycosylation and secretion of this protein. CONCLUSIONS: In this study we have provided the first evidence of protein O-glycosylation in the probiotic L rhamnosus GG. The major secreted protein Msp1 is glycosylated with ConA reactive sugars at the serine residues at 106 and 107. Glycosylation is not required for the peptidoglycan hydrolase activity of Msp1 nor for Akt activation capacity in epithelial cells, but appears to be important for its stability and protection against proteases.


Assuntos
Lacticaseibacillus rhamnosus/metabolismo , Proteína 1 de Superfície de Merozoito/biossíntese , Proteínas Recombinantes/biossíntese , Sequência de Aminoácidos , Células CACO-2 , Escherichia coli/metabolismo , Glicopeptídeos/análise , Glicosilação , Humanos , Lacticaseibacillus casei/metabolismo , Espectrometria de Massas , Proteína 1 de Superfície de Merozoito/genética , Proteína 1 de Superfície de Merozoito/metabolismo , Dados de Sequência Molecular , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
12.
Front Nutr ; 9: 935711, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35990340

RESUMO

Human milk oligosaccharides (HMOs) are structurally diverse oligosaccharides present in breast milk, supporting the development of the gut microbiota and immune system. Previously, 2-HMO (2'fucosyllactose, lacto-N-neotetraose) compared to control formula feeding was associated with reduced risk of lower respiratory tract infections (LRTIs), in part linked to lower acetate and higher bifidobacteria proportions. Here, our objective was to gain further insight into additional molecular pathways linking the 2-HMO formula feeding and LRTI mitigation. From the same trial, we measured the microbiota composition and 743 known biochemical species in infant stool at 3 months of age using shotgun metagenomic sequencing and untargeted mass spectrometry metabolomics. We used multivariate analysis to identify biochemicals associated to 2-HMO formula feeding and LRTI and integrated those findings with the microbiota compositional data. Three molecular pathways stood out: increased gamma-glutamylation and N-acetylation of amino acids and decreased inflammatory signaling lipids. Integration of stool metagenomic data revealed some Bifidobacterium and Bacteroides species to be implicated. These findings deepen our understanding of the infant gut/microbiome co-metabolism in early life and provide evidence for how such metabolic changes may influence immune competence at distant mucosal sites such as the airways.

13.
Microorganisms ; 10(8)2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-36014023

RESUMO

Akkermansia muciniphila is a champion of mucin degradation in the human gastrointestinal tract. Here, we report the isolation of six novel strains from healthy human donors and their genomic, proteomic and physiological characterization in comparison to the type-strains A. muciniphila MucT and A. glycaniphila PytT. Complete genome sequencing revealed that, despite their large genomic similarity (>97.6%), the novel isolates clustered into two distinct subspecies of A. muciniphila: Amuc1, which includes the type-strain MucT, and AmucU, a cluster of unassigned strains that have not yet been well characterized. CRISPR analysis showed all strains to be unique and confirmed that single healthy subjects can carry more than one A. muciniphila strain. Mucin degradation pathways were strongly conserved amongst all isolates, illustrating the exemplary niche adaptation of A. muciniphila to the mucin interface. This was confirmed by analysis of the predicted glycoside hydrolase profiles and supported by comparing the proteomes of A. muciniphila strain H2, belonging to the AmucU cluster, to MucT and A. glycaniphila PytT (including 610 and 727 proteins, respectively). While some intrinsic resistance was observed among the A. muciniphila straind, none of these seem to pose strain-specific risks in terms of their antibiotic resistance patterns nor a significant risk for the horizontal transfer of antibiotic resistance determinants, opening the way to apply the type-strain MucT or these new A. muciniphila strains as next generation beneficial microbes.

14.
Genome Biol ; 22(1): 209, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34261503

RESUMO

BACKGROUND: Akkermansia muciniphila is a human gut microbe with a key role in the physiology of the intestinal mucus layer and reported associations with decreased body mass and increased gut barrier function and health. Despite its biomedical relevance, the genomic diversity of A. muciniphila remains understudied and that of closely related species, except for A. glycaniphila, unexplored. RESULTS: We present a large-scale population genomics analysis of the Akkermansia genus using 188 isolate genomes and 2226 genomes assembled from 18,600 metagenomes from humans and other animals. While we do not detect A. glycaniphila, the Akkermansia strains in the human gut can be grouped into five distinct candidate species, including A. muciniphila, that show remarkable whole-genome divergence despite surprisingly similar 16S rRNA gene sequences. These candidate species are likely human-specific, as they are detected in mice and non-human primates almost exclusively when kept in captivity. In humans, Akkermansia candidate species display ecological co-exclusion, diversified functional capabilities, and distinct patterns of associations with host body mass. Analysis of CRISPR-Cas loci reveals new variants and spacers targeting newly discovered putative bacteriophages. Remarkably, we observe an increased relative abundance of Akkermansia when cognate predicted bacteriophages are present, suggesting ecological interactions. A. muciniphila further exhibits subspecies-level genetic stratification with associated functional differences such as a putative exo/lipopolysaccharide operon. CONCLUSIONS: We uncover a large phylogenetic and functional diversity of the Akkermansia genus in humans. This variability should be considered in the ongoing experimental and metagenomic efforts to characterize the health-associated properties of A. muciniphila and related bacteria.


Assuntos
Microbioma Gastrointestinal/genética , Genoma Bacteriano , Metagenoma , Filogenia , Akkermansia/classificação , Akkermansia/genética , Akkermansia/metabolismo , Akkermansia/virologia , Animais , Bacteriófagos/crescimento & desenvolvimento , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Variação Genética , Humanos , Camundongos , Óperon , RNA Ribossômico 16S/genética
15.
Trends Microbiol ; 28(5): 340-348, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32298612

RESUMO

Cell-surface-located proteinaceous appendages, such as flagella and fimbriae or pili, are ubiquitous in bacterial communities. Here, we focus on conserved type IV pili (T4P) produced by bacteria in the intestinal tract, one of the most densely populated human ecosystems. Computational analysis revealed that approximately 30% of known intestinal bacteria are predicted to produce T4P. To rationalize how T4P allow intestinal bacteria to interact with their environment, other microbiota members, and host cells, we review their established role in gut commensals and pathogens with respect to adherence, motility, and biofilm formation, as well as protein secretion and DNA uptake. This work indicates that T4P are widely spread among the known members of the intestinal microbiota and that their contribution to human health might be underestimated.


Assuntos
Bactérias/metabolismo , Fenômenos Fisiológicos Bacterianos , Proteínas de Fímbrias/metabolismo , Fímbrias Bacterianas/metabolismo , Microbioma Gastrointestinal/fisiologia , Aderência Bacteriana/fisiologia , Biofilmes/crescimento & desenvolvimento , Humanos , Locomoção/fisiologia
16.
Front Bioeng Biotechnol ; 8: 1024, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32974330

RESUMO

Lacticaseibacillus rhamnosus GG is one of the best studied lactic acid bacteria in the context of probiotic effects. L. rhamnosus GG has been shown to prevent diarrhea in children and adults and has been implicated to have mitigating or preventive effects in several disorders connected to microbiota dysbiosis. The probiotic effects are largely attributed to its adhesive heterotrimeric sortase-dependent pili, encoded by the spaCBA-srtC1 gene cluster. Indeed, the strain-specific SpaCBA pili have been shown to contribute to adherence, biofilm formation and host signaling. In this work we set out to generate non-GMO derivatives of L. rhamnosus GG that adhere stronger to mucus compared to the wild-type strain using chemical mutagenesis. We selected 13 derivatives that showed an increased mucus-adherent phenotype. Deep shotgun resequencing of the strains enabled division of the strains into three classes, two of which revealed SNPs (single nucleotide polymorphisms) in the spaA and spaC genes encoding the shaft and tip adhesive pilins, respectively. Strikingly, the other class derivatives demonstrated less clear genotype - phenotype relationships, illustrating that pili biogenesis and structure is also affected by other processes. Further characterization of the different classes of derivatives was performed by PacBio SMRT sequencing and RNAseq analysis, which resulted in the identification of molecular candidates driving pilin biosynthesis and functionality. In conclusion, we report on the generation and characterization of three classes of strongly adherent L. rhamnosus GG derivatives that show an increase in adhesion to mucus. These are of special interest as they provide a window on processes and genes driving piliation and its control in L. rhamnosus GG and offer a variety of non-GMO derivatives of this key probiotic strain that are applicable in food products.

17.
Trends Microbiol ; 27(1): 17-25, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30219265

RESUMO

Bacterial communities are known to impact human health and disease. Mixed species biofilms, mostly pathogenic in nature, have been observed in dental and gastric infections as well as in intestinal diseases, chronic gut wounds and colon cancer. Apart from the appendix, the presence of thick polymicrobial biofilms in the healthy gut mucosa is still debated. Polymicrobial biofilms containing potential pathogens appear to be an early-warning signal of developing disease and can be regarded as a tipping point between a healthy and a diseased state of the gut mucosa. Key biofilm-forming pathogens and associated molecules hold promise as biomarkers. Criteria to distinguish microcolonies from biofilms are crucial to provide clarity when reporting biofilm-related phenomena in health and disease in the gut.


Assuntos
Bactérias/crescimento & desenvolvimento , Infecções Bacterianas/diagnóstico , Biofilmes/crescimento & desenvolvimento , Biomarcadores/análise , Colo/microbiologia , Microbioma Gastrointestinal , Microbiota , Humanos
18.
Nat Commun ; 10(1): 5403, 2019 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-31776333

RESUMO

Glycosylation of proteins profoundly impacts their physical and biological properties. Yet our ability to engineer novel glycoprotein structures remains limited. Established bacterial glycoengineering platforms require secretion of the acceptor protein to the periplasmic space and preassembly of the oligosaccharide substrate as a lipid-linked precursor, limiting access to protein and glycan substrates respectively. Here, we circumvent these bottlenecks by developing a facile glycoengineering platform that operates in the bacterial cytoplasm. The Glycoli platform leverages a recently discovered site-specific polypeptide glycosyltransferase together with variable glycosyltransferase modules to synthesize defined glycans, of bacterial or mammalian origin, directly onto recombinant proteins in the E. coli cytoplasm. We exploit the cytoplasmic localization of this glycoengineering platform to generate a variety of multivalent glycostructures, including self-assembling nanomaterials bearing hundreds of copies of the glycan epitope. This work establishes cytoplasmic glycoengineering as a powerful platform for producing glycoprotein structures with diverse future biomedical applications.


Assuntos
Citoplasma/metabolismo , Glicoproteínas/biossíntese , Engenharia Metabólica/métodos , Benzazepinas , Epitopos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Glucose/química , Glucose/metabolismo , Glucosiltransferases/metabolismo , Glicoproteínas/genética , Glicoproteínas/imunologia , Glicosilação , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Monossacarídeos , Polissacarídeos/metabolismo , Regiões Promotoras Genéticas , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética
19.
Microbiome ; 7(1): 49, 2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30925932

RESUMO

BACKGROUND: A vaginal microbiota dominated by lactobacilli (particularly Lactobacillus crispatus) is associated with vaginal health, whereas a vaginal microbiota not dominated by lactobacilli is considered dysbiotic. Here we investigated whether L. crispatus strains isolated from the vaginal tract of women with Lactobacillus-dominated vaginal microbiota (LVM) are pheno- or genotypically distinct from L. crispatus strains isolated from vaginal samples with dysbiotic vaginal microbiota (DVM). RESULTS: We studied 33 L. crispatus strains (n = 16 from LVM; n = 17 from DVM). Comparison of these two groups of strains showed that, although strain differences existed, both groups degraded various carbohydrates, produced similar amounts of organic acids, inhibited Neisseria gonorrhoeae growth, and did not produce biofilms. Comparative genomics analyses of 28 strains (n = 12 LVM; n = 16 DVM) revealed a novel, 3-fragmented glycosyltransferase gene that was more prevalent among strains isolated from DVM. Most L. crispatus strains showed growth on glycogen-supplemented growth media. Strains that showed less-efficient (n = 6) or no (n = 1) growth on glycogen all carried N-terminal deletions (respectively, 29 and 37 amino acid deletions) in a putative pullulanase type I protein. DISCUSSION: L. crispatus strains isolated from LVM were not phenotypically distinct from L. crispatus strains isolated from DVM; however, the finding that the latter were more likely to carry a 3-fragmented glycosyltransferase gene may indicate a role for cell surface glycoconjugates, which may shape vaginal microbiota-host interactions. Furthermore, the observation that variation in the pullulanase type I gene is associated with growth on glycogen discourages previous claims that L. crispatus cannot directly utilize glycogen.


Assuntos
Disbiose/microbiologia , Genômica/métodos , Glicogênio/metabolismo , Lactobacillus crispatus/isolamento & purificação , Vagina/microbiologia , Proteínas de Bactérias/genética , Feminino , Genoma Bacteriano , Glicosilação , Glicosiltransferases/genética , Humanos , Lactobacillus crispatus/genética , Lactobacillus crispatus/metabolismo , Neisseria gonorrhoeae/crescimento & desenvolvimento , Fenótipo , Filogenia , Análise de Sequência de DNA
20.
Microb Biotechnol ; 11(4): 571-574, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29927545

RESUMO

The Human Microbiome, as well as the exploration of the microorganisms inhabiting the human body, are not only integral to the field of microbiology but represent an intrinsic part of all human beings. Consequently, along with scientists, artists have been inspired by the microbiome: transforming it in to tangible artefacts in order to critically question, reflect on and break down the barrier between humans and their microcohabitants. By artistic means, artists help us to understand how microbial research topics are inevitably affected by societal influences, including (health) politics, economics and the arts. Fifty Percent Human is a multidisciplinary artistic research project that aims to reshape our understanding of the human body and its environment as well as to explore possibilities for conscious coexistence in order to bridge the gap between science and society.


Assuntos
Arte , Microbiota , Criatividade , Ecossistema , Humanos , Filosofia
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